Science.gov

Sample records for axial-vector currents

  1. An Unbroken Axial-Vector Current Conservation Law

    NASA Astrophysics Data System (ADS)

    Sharafiddinov, Rasulkhozha S.

    2016-03-01

    The mass, energy and momentum of the neutrino of a true flavor have an axial-vector nature. As a consequence, the left-handed truly neutral neutrino in an axial-vector field of emission can be converted into a right-handed one and vice versa. This predicts the unidenticality of masses, energies and momenta of neutrinos of the different components. Recognizing such a difference in masses, energies, momenta and accepting that the left-handed axial-vector neutrino and the right-handed antineutrino of true neutrality refer to long-lived C-odd leptons, and the right-handed truly neutral neutrino and the left-handed axial-vector antineutrino are of short-lived fermions of C-oddity, we would write a new CP-even Dirac equation taking into account the flavor symmetrical axial-vector mass, energy and momentum matrices. Their presence explains the spontaneous mirror symmetry violation, confirming that an axial-vector current conservation law has never violated. They reflect the availability of a mirror Minkowski space in which a neutrino is characterized by left as well as by right space-time coordinates. Therefore, it is not surprising that whatever the main purposes experiments about a quasielastic axial-vector mass say in favor of an axial-vector mirror Minkowski space-time.

  2. An Unbroken Axial-Vector Current Conservation Law

    NASA Astrophysics Data System (ADS)

    Sharafiddinov, Rasulkhozha S.

    2016-04-01

    The mass, energy and momentum of the neutrino of a true flavor have an axial-vector nature. As a consequence, the left-handed truly neutral neutrino in an axial-vector field of emission can be converted into a right-handed one and vice versa. This predicts the unidenticality of masses, energies and momenta of neutrinos of the different components. Recognizing such a difference in masses, energies, momenta and accepting that the left-handed axial-vector neutrino and the right-handed antineutrino of true neutrality refer to long-lived C-odd leptons, and the right-handed truly neutral neutrino and the left-handed axial-vector antineutrino are of short-lived fermions of C-oddity, we would write a new CP-even Dirac equation taking into account the flavor symmetrical axial-vector mass, energy and momentum matrices. Their presence explains the spontaneous mirror symmetry violation, confirming that an axial-vector current conservation law has never violated. They reflect the availability of a mirror Minkowski space in which a neutrino is characterized by left as well as by right space-time coordinates. Therefore, it is not surprising that whatever the main purposes experiments about a quasielastic axial-vector mass say in favor of an axial-vector mirror Minkowski space-time.

  3. Path-integral solution for a two-dimensional model with axial-vector-current--pseudoscalar derivative interaction

    SciTech Connect

    Botelho, L.C.L.

    1985-03-15

    We study a two-dimensional quantum field model with axial-vector-current--pseudoscalar derivative interaction using path-integral methods. We construct an effective Lagrangian by performing a chiral change in the fermionic variables leading to an exact solution of the model.

  4. An Axial-Vector Photon in a Mirror World

    NASA Astrophysics Data System (ADS)

    Sharafiddinov, Rasulkhozha S.

    2016-03-01

    The unity of symmetry laws emphasizes, in the case of a mirror CP-even Dirac Lagrangian, the ideas of the left- and right-handed axial-vector photons referring to long- and short-lived bosons of true neutrality, respectively. Such a difference in lifetimes expresses the unidenticality of masses, energies and momenta of axial-vector photons of the different components. They define the unified field theory equation of C-odd particles with an integral spin. Together with a new equation of a theory of truly neutral particles with the half-integral spin, the latter reflects the availability in their nature of the second type of the local axial-vector gauge transformation responsible for origination in the Lagrangian of C-oddity of an interaction Newton component giving an axial-vector mass to all the interacting particles and fields. The mirror axial-vector mass, energy and momentum operators constitute a CP-invariant equation of quantum mechanics, confirming that each of them can individually influence on matter field. Thereby, findings suggest at the level of the mass-charge structure of gauge invariance a new equation for the C-noninvariant Lagrangian.

  5. Charmless Hadronic B Decays into Vector, Axial Vector and Tensor Final States at BaBar

    SciTech Connect

    Gandini, Paolo; /Milan U. /INFN, Milan

    2012-04-06

    We present experimental measurements of branching fraction and longitudinal polarization fraction in charmless hadronic B decays into vector, axial vector and tensor final states with the final dataset of BABAR. Measurements of such kind of decays are a powerful tool both to test the Standard Model and search possible sources of new physics. In this document we present a short review of the last experimental results at BABAR concerning charmless quasi two-body decays in final states containing particles with spin 1 or spin 2 and different parities. This kind of decays has received considerable theoretical interest in the last few years and this particular attention has led to interesting experimental results at the current b-factories. In fact, the study of longitudinal polarization fraction f{sub L} in charmless B decays to vector vector (VV), vector axial-vector (VA) and axial-vector axial-vector (AA) mesons provides information on the underlying helicity structure of the decay mechanism. Naive helicity conservation arguments predict a dominant longitudinal polarization fraction f{sub L} {approx} 1 for both tree and penguin dominated decays and this pattern seems to be confirmed by tree-dominated B {yields} {rho}{rho} and B{sup +} {yields} {Omega}{rho}{sup +} decays. Other penguin dominated decays, instead, show a different behavior: the measured value of f{sub L} {approx} 0.5 in B {yields} {phi}K* decays is in contrast with naive Standard Model (SM) calculations. Several solutions have been proposed such as the introduction of non-factorizable terms and penguin-annihilation amplitudes, while other explanations invoke new physics. New modes have been investigated to shed more light on the problem.

  6. Axial-vector dominance predictions in quasielastic neutrino-nucleus scattering

    NASA Astrophysics Data System (ADS)

    Amaro, J. E.; Ruiz Arriola, E.

    2016-03-01

    The axial form factor plays a crucial role in quasielastic neutrino-nucleus scattering, but the error of the theoretical cross section due to uncertainties of GA remains to be established. Conversely, the extraction of GA from the neutrino nucleus cross section suffers from large systematic errors due to nuclear model dependencies, while the use of single-parameter dipole fits underestimates the errors and prevents an identification of the relevant kinematics for this determination. We propose to use a generalized axial-vector-meson dominance in conjunction with large-Nc and high-energy QCD constraints to model the nucleon axial form factor, as well as the half-width rule as an a priori uncertainty estimate. The minimal hadronic ansatz comprises the sum of two monopoles corresponding to the lightest axial-vector mesons being coupled to the axial current. The parameters of the resulting axial form factor are the masses and widths of the two axial mesons as obtained from the averaged Particle Data Group values. By applying the half-width rule in a Monte Carlo simulation, a distribution of theoretical predictions can then be generated for the neutrino-nucleus quasielastic cross section. We test the model by applying it to the (νμ,μ ) quasielastic cross section from 12 for the kinematics of the MiniBooNE experiment. The resulting predictions have no free parameters. We find that the relativistic Fermi gas model globally reproduces the experimental data, giving χ2/# bins=0.81 . A Q2-dependent error analysis of the neutrino data shows that the uncertainties in the axial form factor GA(Q2) are comparable to the ones induced by the a priori half-width rule. We identify the most sensitive region to be in the range 0.2 ≲Q2≲0.6 GeV2 .

  7. Clean measurements of the nucleon axial-vector and free-neutron magnetic form factors

    SciTech Connect

    Deur, Alexandre P.

    2013-11-01

    We discuss the feasibility of a weak charged current experiment using a low energy electron beam. A first goal is to measure the Q^2 dependence of the axial-vector form factor g_a(Q^2). It can be measured model-independently and as robustly as for electromagnetic form factors from typical electron scattering experiments, in contrast to the methods used so far to measure g_a(Q^2). If g_a(Q^2) follows a dipole form, the axial mass can be extracted with a better accuracy than the world data altogether. The most important detection equipment would be a segmented neutron detector with good momentum and angular resolution that is symmetric about the beam direction, and covers a moderate angular range. A high intensity beam (100 uA) is necessary. Beam polarization is highly desirable as it provides a clean measurement of the backgrounds. Beam energies between 70 and 110 MeV are ideal. This range would provide a Q^2 mapping of g_a between 0.01

  8. Heavy vector and axial-vector mesons in hot and dense asymmetric strange hadronic matter

    NASA Astrophysics Data System (ADS)

    Kumar, Arvind; Chhabra, Rahul

    2015-09-01

    We calculate the effects of finite density and temperature of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector (D*,Ds*,B*,Bs*) and axial-vector (D1,D1 s,B1,B1 s) mesons, using the chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift in decay constant of above vector and axial-vector mesons. In the quantum chromodynamics sum rule approach, the properties, e.g., the masses and decay constants of vector and axial-vector mesons are written in terms of quark and gluon condensates. These quark and gluon condensates are evaluated in the present work within the chiral SU(3) model, through the medium modification of scalar-isoscalar fields σ and ζ , the scalar-isovector field δ , and the scalar dilaton field χ , in the strange hadronic medium which includes both nucleons as well as hyperons. As we shall see in detail, the masses and decay constants of heavy vector and axial-vector mesons are affected significantly from isospin asymmetry and the strangeness fraction of the medium, and these modifications may influence the experimental observables produced in heavy-ion collision experiments. The results of present investigations of in-medium properties of vector and axial-vector mesons at finite density and temperature of strange hadronic medium may be helpful for understanding the experimental data from heavy-ion collision experiments in particular for the compressed baryonic matter (CBM) experiment of the FAIR facility at GSI, Germany.

  9. Radiative corrections to the nucleon axial vector coupling constant in the chiral soliton quark model

    SciTech Connect

    Duck, I. )

    1993-04-01

    Second-order radiative corrections to the nucleon axial vector coupling constant from gluon, pion, and sigma meson exchange are calculated in the chiral soliton quark model. Many apparent processes are found not to contribute. The soliton is elastically decoupled from meson radiative corrections which are dominated by a gluon exchange contribution equivalent to a gluonic hybrid component of the nucleon. A 30% radiative reduction of the axial coupling strength is indicated.

  10. Scalar mesons in a linear sigma model with (axial-)vector mesons

    SciTech Connect

    Parganlija, D.; Kovacs, P.; Wolf, Gy.; Giacosa, F.; Rischke, D. H.

    2013-03-25

    The structure of the scalar mesons has been a subject of debate for many decades. In this work we look for qq states among the physical resonances using an extended Linear Sigma Model that contains scalar, pseudoscalar, vector, and axial-vector mesons both in the non-strange and strange sectors. We perform global fits of meson masses, decay widths and amplitudes in order to ascertain whether the scalar qq states are below or above 1 GeV. We find the scalar states above 1 GeV to be preferred as qq states.

  11. Parity-Violating Electron Deuteron Scattering and the Proton's Neutral Weak Axial Vector Form Factor

    SciTech Connect

    Ito, Takeyasu; Averett, Todd; Barkhuff, David; Batigne, Guillaume; Beck, Douglas; Beise, Elizabeth; Blake, A.; Breuer, Herbert; Carr, Robert; Clasie, Benjamin; Covrig, Silviu; Danagoulian, Areg; Dodson, George; Dow, Karen; Dutta, Dipangkar; Farkhondeh, Manouchehr; Filippone, Bradley; FRANKLIN, W.; Furget, Christophe; Gao, Haiyan; Gao, Juncai; Gustafsson, Kenneth; Hannelius, Lars; Hasty, R.; Allen, Alice; Herda, M.C.; Jones, CE; King, Paul; Korsch, Wolfgang; Kowalski, Stanley; Kox, Serge; Kramer, Kevin; Lee, P.; Liu, Jinghua; Martin, Jeffery; McKeown, Robert; Mueller, B.; Pitt, Mark; Plaster, Bradley; Quemener, Gilles; Real, Jean-Sebastien; Ritter, J.; Roche, Julie; Savu, V.; Schiavilla, Rocco; Seely, Charles; Spayde, Damon; Suleiman, Riad; Taylor, S.; Tieulent, Raphael; Tipton, Bryan; Tsentalovich, E.; Wells, Steven; Yang, Bin; Yuan, Jing; Yun, Junho; Zwart, Townsend

    2004-03-01

    We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from the deuteron at backward angles at Q2 = 0.038 (GeV/c)2. This quantity provides a determination of the neutral weak axial vector form factor of the nucleon, which can potentially receive large electroweak corrections. The measured asymmetry A = z3.51±0.57 (stat)±0.58 (syst) ppm is consistent with theoretical predictions. We also report on updated results of the previous experiment at Q2 = 0.091 (GeV/c)2, which are also consistent with theoretical predictions.

  12. Determination of the axial-vector weak coupling constant with ultracold neutrons.

    PubMed

    Liu, J; Mendenhall, M P; Holley, A T; Back, H O; Bowles, T J; Broussard, L J; Carr, R; Clayton, S; Currie, S; Filippone, B W; García, A; Geltenbort, P; Hickerson, K P; Hoagland, J; Hogan, G E; Hona, B; Ito, T M; Liu, C-Y; Makela, M; Mammei, R R; Martin, J W; Melconian, D; Morris, C L; Pattie, R W; Pérez Galván, A; Pitt, M L; Plaster, B; Ramsey, J C; Rios, R; Russell, R; Saunders, A; Seestrom, S J; Sondheim, W E; Tatar, E; Vogelaar, R B; VornDick, B; Wrede, C; Yan, H; Young, A R

    2010-10-29

    A precise measurement of the neutron decay β asymmetry A₀ has been carried out using polarized ultracold neutrons from the pulsed spallation ultracold neutron source at the Los Alamos Neutron Science Center. Combining data obtained in 2008 and 2009, we report A₀ = -0.119 66±0.000 89{-0.001 40}{+0.001 23}, from which we determine the ratio of the axial-vector to vector weak coupling of the nucleon g{A}/g{V}=-1.275 90{-0.004 45}{+0.004 09}. PMID:21231098

  13. Massive Yang-Mills for vector and axial-vector spectral functions at finite temperature

    NASA Astrophysics Data System (ADS)

    Hohler, Paul M.; Rapp, Ralf

    2016-05-01

    The hadronic mechanism which leads to chiral symmetry restoration is explored in the context of the ρπa1 system using Massive Yang-Mills, a hadronic effective theory which governs their microscopic interactions. In this approach, vector and axial-vector mesons are implemented as gauge bosons of a local chiral gauge group. We have previously shown that this model can describe the experimentally measured vector and axial-vector spectral functions in vacuum. Here, we carry the analysis to finite temperatures by evaluating medium effects in a pion gas and calculating thermal spectral functions. We find that the spectral peaks in both channels broaden along with a noticeable downward mass shift in the a1 spectral peak and negligible movement of the ρ peak. The approach toward spectral function degeneracy is accompanied by a reduction of chiral order parameters, i.e., the pion decay constant and scalar condensate. Our findings suggest a mechanism where the chiral mass splitting induced in vacuum is burned off. We explore this mechanism and identify future investigations which can further test it.

  14. Vacuum effects in magnetic field with with account for fermion anomalous magnetic moment and axial-vector interaction

    NASA Astrophysics Data System (ADS)

    Bubnov, Andrey; Gubina, Nadezda; Zhukovsky, Vladimir

    2016-05-01

    We study vacuum polarization effects in the model of Dirac fermions with additional interaction of an anomalous magnetic moment with an external magnetic field and fermion interaction with an axial-vector condensate. The proper time method is used to calculate the one-loop vacuum corrections with consideration for different configurations of the characteristic parameters of these interactions.

  15. 77 FR 4853 - In the Matter of Airbee Wireless, Inc., Axial Vector Engine Corp. (n/k/a Avec Corporation), and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-31

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION In the Matter of Airbee Wireless, Inc., Axial Vector Engine Corp. (n/k/a Avec Corporation), and... accurate information concerning the securities of Axial Vector Engine Corp. (n/k/a Avec...

  16. Invited Parallel Talk: Photoproduction of the Θ+ and its vector and axial-vector structure

    NASA Astrophysics Data System (ADS)

    Kim, H.-Ch.; Goeke, K.; Ledwig, T.; Nam, S. I.

    2009-12-01

    We present recent investigations on the vector and axial-vector transitions of the baryon antide-cuplet within the framework of the self-consistent SU(3) chiral quark-soliton model, taking into account the 1/Nc rotational and linear ms corrections. The main contribution to the electric-like transition form factor comes from the wave-function corrections. This is a consequence of the generalized Ademollo-Gatto theorem. It is also found that in general the leading-order contributions are almost canceled by the rotational 1/Nc corrections. The results are summarized as follows: the vector and tensor K*NΘ coupling constants, gK*NΘ = 0.74-0.87 and fK*NΘ = 0.53-1.16, respectively, and ΓΘ→KN = 0.71 MeV, based on the result of the KNΘ coupling constant gK*NΘ = 0.83. We also show the differential cross sections and beam asymmetries, based on the present results. We also discuss the connection of present results with the original work by Diakonov, Petrov, and Polyakov.

  17. Strong coupling constants of bottom and charmed mesons with scalar, pseudoscalar, and axial vector kaons

    SciTech Connect

    Sundu, H.; Suengue, J. Y.; Sahin, S.; Yinelek, N.; Azizi, K.

    2011-06-01

    The strong coupling constants, g{sub D{sub sDK{sub 0}{sup *}, g{sub B{sub sBK{sub 0}{sup *}, g{sub D{sub s}{sup *}{sub DK}}}}}}, g{sub B{sub s}{sup *}{sub BK}}, g{sub D{sub s}{sup *}{sub DK{sub 1}}} and g{sub B{sub s}{sup *}{sub BK{sub 1}}}, where K{sub 0}{sup *}, K and K{sub 1} are scalar, pseudoscalar, and axial-vector kaon mesons, respectively, are calculated in the framework of three-point QCD sum rules. In particular, the correlation functions of the considered vertices when both B(D) and K{sub 0}{sup *}(K)(K{sub 1}) mesons are off shell are evaluated. In the case of K{sub 1}, which is either K{sub 1}(1270) or K{sub 1}(1400), the mixing between these two states are also taken into account. A comparison of the obtained result with the existing prediction on g{sub D{sub s}{sup *}{sub DK}} as the only coupling constant among the considered vertices, previously calculated in the literature, is also made.

  18. Probing light pseudoscalar, axial vector states through {eta}{sub b}{yields}{tau}{sup +}{tau}{sup -}

    SciTech Connect

    Rashed, Ahmed; Duraisamy, Murugeswaran; Datta, Alakabha

    2010-09-01

    In this paper, we explore the decay {eta}{sub b}{yields}{tau}{sup +}{tau}{sup -} as a probe for a light pseudoscalar or a light axial vector state. We estimate the standard model branching ratio for this decay to be {approx}4x10{sup -9}. We show that considerably larger branching ratios, up to the present experimental limit of {approx}8%, are possible in models with a light pseudoscalar or a light axial vector state. As we do not include possible mixing effects between the light pseudoscalar and the {eta}{sub b}, our results should be reliable when the pseudoscalar mass is away from the {eta}{sub b} mass.

  19. Nucleon and Delta axial-vector couplings in 1/N{sub c}-Baryon Chiral Perturbation Theory

    SciTech Connect

    Goity, Jose Luis; Calle Cordon, Alvaro

    2013-08-01

    In this contribution, baryon axial-vector couplings are studied in the framework of the combined 1/N{sub c} and chiral expansions. This framework is implemented on the basis of the emergent spin-flavor symmetry in baryons at large N{sub c} and HBChPT, and linking both expansions ({xi}-expansion), where 1/N{sub c} is taken to be a quantity order p. The study is carried out including one-loop contributions, which corresponds to order xi to the third for baryon masses and order {xi} square for the axial couplings.

  20. Observation of Pseudoscalar and Axial Vector Resonances in pi- p -> K+ K- pi0 n at 18 GeV

    SciTech Connect

    G.S. Adams; T. Adams; Z. Bar-Yam; J.M. Bishop; V.A. Bodyagin; D.S. Brown; N.M. Cason; S.U. Chung; J.P. Cummings; K. Danyo; A.I. Demianov; S. Denisov; V. Dorofeev; J.P. Dowd; P. Eugenio; X.L. Fan; A.M. Gribushin; R.W. Hackenburg; M. Hayek; J. Hu; E.I. Ivanov; D. Joffe; I. Kachaev; W. Kern; E. King; O.L. Kodolova; V.L. Korotkikh; M.A. Kostin; Joachim Kuhn; V. Lipaev; J.M. Losecco; M. Lu; J.J. Manak; J. Napolitano; M. Nozar; C. Olchanski; A.I. Ostrovidov; T.K. Pedlar; A. Popov; D. Ryabchikov; A.H. Sanjari; L.I. Sarycheva; K.K. Seth; N. Shenhav; X. Shen; W.D. Shephard; N.B. Sinev; D.L. Stienike; S.A. Taegar; D.R. Thompson; A. Tomaradze; I.N. Vardanyan; D.P. Weygand; D. White; H.J. Willutzki; A.A. Yershov

    2001-09-01

    The number of pseudoscalar mesons in the mass range from 1400 to 1500 MeV/c{sup 2} has been a subject of considerable interest for many years, with several experiments having presented evidence for two closely spaced states. A new measurement of the reaction {pi}{sup -} p {yields} K{sup +} K{sup -} {pi}{sup 0}n has been made at a beam energy of 18 GeV. A partial wave analysis of the K{sup +} K{sup -} {pi}{sup 0} system shows evidence for three pseudoscalar resonances, {eta}(1295), {eta}(1416), and {eta}(1485), as well as two axial vectors, f{sub 1}(1285), and f{sub 1}(1420). Their observed masses, widths and decay properties are reported. No signal was observed for C(1480), an I{sub G} J{sup PC} = 1{sup +} 1{sup --} state previously reported in {phi}{pi}{sup 0} decay.

  1. Axial-vector transitions and strong decays of the baryon antidecuplet in the self-consistent SU(3) chiral quark-soliton model

    SciTech Connect

    Ledwig, Tim; Kim, Hyun-Chul; Goeke, Klaus

    2008-09-01

    We investigate the axial-vector transition constants of the baryon antidecuplet to the octet and decuplet within the framework of the self-consistent SU(3) chiral quark-soliton model. Taking into account rotational 1/N{sub c} and linear m{sub s} corrections and using the symmetry-conserving quantization, we calculate the axial-vector transition constants. It is found that the leading-order contributions are generally almost canceled by the rotational 1/N{sub c} corrections. Thus, the m{sub s} corrections turn out to be essential contributions to the axial-vector constants. The decay width of the {theta}{sup +}{yields}NK transition is determined to be {gamma}({theta}{yields}NK)=0.71 MeV, based on the result of the axial-vector transition constant g{sub A}*({theta}{yields}NK)=0.05. In addition, other strong decays of the baryon antidecuplet are investigated. The forbidden decays from the baryon antidecuplet to the decuplet are also studied.

  2. On the Partical Conservation of the U(1) Current

    NASA Astrophysics Data System (ADS)

    Kawarabayashi, K.; Ohta, N.

    1981-11-01

    Recently proposed partial conservation of the U(1) current(PCU1C) is applied to estimate the decay rates of various OZIforbidden processes. The results obtained are in good agreement withexperiments and thus indicate the important role played by the U(1)axial-vector anomaly in these decay processes. Octet Jp = (1/2)+ baryons are next introduced into this scheme and low energy theorems related to the θ dependence of the matrix elements are investigated. Physical consequences of non-zero θ (strong CP-violation) are also discussed with the help of the PCU1C. The results are used to give the bound on θ.

  3. Aspects of QCD current algebra on a null plane

    NASA Astrophysics Data System (ADS)

    Beane, S. R.; Hobbs, T. J.

    2016-09-01

    Consequences of QCD current algebra formulated on a light-like hyperplane are derived for the forward scattering of vector and axial-vector currents on an arbitrary hadronic target. It is shown that current algebra gives rise to a special class of sum rules that are direct consequences of the independent chiral symmetry that exists at every point on the two-dimensional transverse plane orthogonal to the lightlike direction. These sum rules are obtained by exploiting the closed, infinite-dimensional algebra satisfied by the transverse moments of null-plane axial-vector and vector charge distributions. In the special case of a nucleon target, this procedure leads to the Adler-Weisberger, Gerasimov-Drell-Hearn, Cabibbo-Radicati and Fubini-Furlan-Rossetti sum rules. Matching to the dispersion-theoretic language which is usually invoked in deriving these sum rules, the moment sum rules are shown to be equivalent to algebraic constraints on forward S-matrix elements in the Regge limit.

  4. Wess-Zumino current and the structure of the decay tau- -->K- pi- K+ nu tau.

    PubMed

    Coan, T E; Gao, Y S; Liu, F; Stroynowski, R; Artuso, M; Boulahouache, C; Blusk, S; Butt, J; Dambasuren, E; Dorjkhaidav, O; Haynes, J; Menaa, N; Mountain, R; Muramatsu, H; Nandakumar, R; Redjimi, R; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Zhang, Kevin; Mahmood, A H; Csorna, S E; Bonvicini, G; Cinabro, D; Dubrovin, M; Bornheim, A; Lipeles, E; Pappas, S P; Shapiro, A; Weinstein, A J; Briere, R A; Chen, G P; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Adam, N E; Alexander, J P; Berkelman, K; Boisvert, V; Cassel, D G; Duboscq, J E; Ecklund, K M; Ehrlich, R; Galik, R S; Gibbons, L; Gittelman, B; Gray, S W; Hartill, D L; Heltsley, B K; Hsu, L; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Magerkurth, A; Mahlke-Krüger, H; Meyer, T O; Patterson, J R; Pedlar, T K; Peterson, D; Pivarski, J; Riley, D; Sadoff, A J; Schwarthoff, H; Shepherd, M R; Sun, W M; Thayer, J G; Urner, D; Wilksen, T; Weinberger, M; Athar, S B; Avery, P; Breva-Newell, L; Potlia, V; Stoeck, H; Yelton, J; Eisenstein, B I; Gollin, G D; Karliner, I; Lowrey, N; Naik, P; Sedlack, C; Selen, M; Thaler, J J; Williams, J; Edwards, K W; Besson, D; Gao, K Y; Gong, D T; Kubota, Y; Li, S Z; Poling, R; Scott, A W; Smith, A; Stepaniak, C J; Urheim, J; Metreveli, Z; Seth, K K; Tomaradze, A; Zweber, P; Arms, K; Eckhart, E; Gan, K K; Gwon, C; Severini, H; Skubic, P; Asner, D M; Dytman, S A; Mehrabyan, S; Mueller, J A; Nam, S; Savinov, V; Huang, G S; Miller, D H; Pavlunin, V; Sanghi, B; Shibata, E I; Shipsey, I P J; Adams, G S; Chasse, M; Cummings, J P; Danko, I; Napolitano, J; Cronin-Hennessy, D; Park, C S; Park, W; Thayer, J B; Thorndike, E H

    2004-06-11

    We present the first study of the vector (Wess-Zumino) current in tau(-)-->K-pi-K+nu(tau) decay using data collected with the CLEO III detector at the Cornell Electron Storage Ring. We determine the quantitative contributions to the decay width from the vector and axial vector currents. Within the framework of a model by Kühn and Mirkes, we identify the quantitative contributions to the total decay rate from the intermediate states omegapi, rho(')pi, and K*K. PMID:15245150

  5. Study of quasielastic scattering using charged-current νμ-iron interactions in the MINOS near detector

    DOE PAGESBeta

    Adamson, P.

    2015-01-08

    Kinematic distributions from an inclusive sample of 1.41×106 charged-current νμ interactions on iron, obtained using the MINOS near detector exposed to a wide-band beam with peak flux at 3 GeV, are compared to a conventional treatment of neutrino scattering within a Fermi gas nucleus. Results are also used to guide the selection of a subsample enriched in quasielastic νμFe interactions, containing an estimated 123,000 quasielastic events of incident energies 1 < Eν < 8 GeV, with < Eν > = 2.79 GeV. Four additional subsamples representing topological and kinematic sideband regions to quasielastic scattering are also selected for the purposemore » of evaluating backgrounds. Comparisons using subsample distributions in four-momentum transfer Q2 show the Monte Carlo model to be inadequate at low Q2. Its shortcomings are remedied via inclusion of a Q2-dependent suppression function for baryon resonance production, developed from the data. A chi-square fit of the resulting Monte Carlo simulation to the shape of the Q2 distribution for the quasielastic-enriched sample is carried out with the axial-vector mass MA of the dipole axial-vector form factor of the neutron as a free parameter. Furthermore, the effective MA which best describes the data is 1.23+0.13-0.09(fit)+0.12-0.15(syst) GeV.« less

  6. First Measurement of the Muon Neutrino Charged Current Quasielastic Double Differential Cross Section

    SciTech Connect

    Aguilar-Arevalo, A.A.; Anderson, C.E.; Bazarko, A.O.; Brice, S.J.; Brown, B.C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J.M.; Cox, D.C.; Curioni, A.; /Yale U. /Columbia U.

    2010-02-01

    A high-statistics sample of charged-current muon neutrino scattering events collected with the MiniBooNE experiment is analyzed to extract the first measurement of the double differential cross section (d{sup 2}{sigma}/dT{sub {mu}}d cos {theta}{sub {mu}}) for charged-current quasielastic (CCQE) scattering on carbon. This result features minimal model dependence and provides the most complete information on this process to date. With the assumption of CCQE scattering, the absolute cross section as a function of neutrino energy ({sigma}[E{sub {nu}}]) and the single differential cross section (d{sigma}/dQ{sup 2}) are extracted to facilitate comparison with previous measurements. These quantities may be used to characterize an effective axial-vector form factor of the nucleon and to improve the modeling of low-energy neutrino interactions on nuclear targets. The results are relevant for experiments searching for neutrino oscillations.

  7. First measurement of the muon neutrino charged current quasielastic double differential cross section

    SciTech Connect

    Aguilar-Arevalo, A. A.; Anderson, C. E.; Curioni, A.; Fleming, B. T.; Linden, S. K.; Soderberg, M.; Spitz, J.; Bazarko, A. O.; Laird, E. M.; Meyers, P. D.; Patterson, R. B.; Shoemaker, F. C.; Tanaka, H. A.; Brice, S. J.; Brown, B. C.; Finley, D. A.; Ford, R.; Garcia, F. G.; Kasper, P.; Kobilarcik, T.

    2010-05-01

    A high-statistics sample of charged-current muon neutrino scattering events collected with the MiniBooNE experiment is analyzed to extract the first measurement of the double differential cross section ((d{sup 2{sigma}}/dT{sub {mu}d}cos{theta}{sub {mu}})) for charged-current quasielastic (CCQE) scattering on carbon. This result features minimal model dependence and provides the most complete information on this process to date. With the assumption of CCQE scattering, the absolute cross section as a function of neutrino energy ({sigma}[E{sub {nu}}]) and the single differential cross section ((d{sigma}/dQ{sup 2})) are extracted to facilitate comparison with previous measurements. These quantities may be used to characterize an effective axial-vector form factor of the nucleon and to improve the modeling of low-energy neutrino interactions on nuclear targets. The results are relevant for experiments searching for neutrino oscillations.

  8. First Measurement of Muon Neutrino Charged Current Quasielastic (CCQE) Double Differential Cross Section

    SciTech Connect

    Katori, Teppei; /MIT, LNS

    2009-09-01

    Using a high statistics sample of muon neutrino charged current quasielastic (CCQE) events, we report the first measurement of the double differential cross section (d{sup 2}{sigma}/dT{sub {mu}}d cos {theta}{sub {mu}}) for this process. The result features reduced model dependence and supplies the most complete information on neutrino CCQE scattering to date. Measurements of the absolute cross section as a function of neutrino energy ({sigma}[E{sub v}{sup QE,RFG}]) and the single differential cross section (d{sigma}/dQ{sub QE}{sup 2}) are also provided, largely to facilitate comparison with prior measurements. This data is of particular use for understanding the axial-vector form factor of the nucleon as well as improving the simulation of low energy neutrino interactions on nuclear targets, which is of particular relevance for experiments searching for neutrino oscillations.

  9. Study of quasielastic scattering using charged-current νμ-iron interactions in the MINOS near detector

    SciTech Connect

    Adamson, P.

    2015-01-08

    Kinematic distributions from an inclusive sample of 1.41×106 charged-current νμ interactions on iron, obtained using the MINOS near detector exposed to a wide-band beam with peak flux at 3 GeV, are compared to a conventional treatment of neutrino scattering within a Fermi gas nucleus. Results are also used to guide the selection of a subsample enriched in quasielastic νμFe interactions, containing an estimated 123,000 quasielastic events of incident energies 1 < Eν < 8 GeV, with < Eν > = 2.79 GeV. Four additional subsamples representing topological and kinematic sideband regions to quasielastic scattering are also selected for the purpose of evaluating backgrounds. Comparisons using subsample distributions in four-momentum transfer Q2 show the Monte Carlo model to be inadequate at low Q2. Its shortcomings are remedied via inclusion of a Q2-dependent suppression function for baryon resonance production, developed from the data. A chi-square fit of the resulting Monte Carlo simulation to the shape of the Q2 distribution for the quasielastic-enriched sample is carried out with the axial-vector mass MA of the dipole axial-vector form factor of the neutron as a free parameter. Furthermore, the effective MA which best describes the data is 1.23+0.13-0.09(fit)+0.12-0.15(syst) GeV.

  10. Nonperturbative renormalization of the axial current in Nf=3 lattice QCD with Wilson fermions and a tree-level improved gauge action

    NASA Astrophysics Data System (ADS)

    Bulava, John; Della Morte, Michele; Heitger, Jochen; Wittemeier, Christian

    2016-06-01

    We nonperturbatively determine the renormalization factor of the axial vector current in lattice QCD with Nf=3 flavors of Wilson-clover fermions and the tree-level Symanzik-improved gauge action. The (by now standard) renormalization condition is derived from the massive axial Ward identity, and it is imposed among Schrödinger functional states with large overlap on the lowest lying hadronic state in the pseudoscalar channel, in order to reduce kinematically enhanced cutoff effects. We explore a range of couplings relevant for simulations at lattice spacings of ≈0.09 fm and below. An interpolation formula for ZA(g02) , smoothly connecting the nonperturbative values to the 1-loop expression, is provided together with our final results.

  11. Limit on Tensor Currents from ^{8}Li β Decay.

    PubMed

    Sternberg, M G; Segel, R; Scielzo, N D; Savard, G; Clark, J A; Bertone, P F; Buchinger, F; Burkey, M; Caldwell, S; Chaudhuri, A; Crawford, J E; Deibel, C M; Greene, J; Gulick, S; Lascar, D; Levand, A F; Li, G; Pérez Galván, A; Sharma, K S; Van Schelt, J; Yee, R M; Zabransky, B J

    2015-10-30

    In the standard model, the weak interaction is formulated with a purely vector-axial-vector (V-A) structure. Without restriction on the chirality of the neutrino, the most general limits on tensor currents from nuclear β decay are dominated by a single measurement of the β-ν[over ¯] correlation in ^{6}He β decay dating back over a half century. In the present work, the β-ν[over ¯]-α correlation in the β decay of ^{8}Li and subsequent α-particle breakup of the ^{8}Be^{*} daughter was measured. The results are consistent with a purely V-A interaction and in the case of couplings to right-handed neutrinos (C_{T}=-C_{T}^{'}) limits the tensor fraction to |C_{T}/C_{A}|^{2}<0.011 (95.5% C.L.). The measurement confirms the ^{6}He result using a different nuclear system and employing modern ion-trapping techniques subject to different systematic uncertainties. PMID:26565463

  12. Observation of a New Narrow Axial-Vector Meson a1(1420).

    PubMed

    Adolph, C; Akhunzyanov, R; Alexeev, M G; Alexeev, G D; Amoroso, A; Andrieux, V; Anosov, V; Austregesilo, A; Azevedo, C; Badełek, B; Balestra, F; Barth, J; Beck, R; Bedfer, Y; Bernhard, J; Bicker, K; Bielert, E R; Birsa, R; Bisplinghoff, J; Bodlak, M; Boer, M; Bordalo, P; Bradamante, F; Braun, C; Bressan, A; Büchele, M; Burtin, E; Chang, W-C; Chiosso, M; Choi, I; Chung, S U; Cicuttin, A; Crespo, M L; Curiel, Q; Dalla Torre, S; Dasgupta, S S; Dasgupta, S; Denisov, O Yu; Dhara, L; Donskov, S V; Doshita, N; Dünnweber, W; Duic, V; Dziewiecki, M; Efremov, A; Eversheim, P D; Eyrich, W; Faessler, M; Ferrero, A; Finger, M; Finger, M; Fischer, H; Franco, C; du Fresne von Hohenesche, N; Friedrich, J M; Frolov, V; Gautheron, F; Gavrichtchouk, O P; Gerassimov, S; Gnesi, I; Gorzellik, M; Grabmüller, S; Grasso, A; Grosse-Perdekamp, M; Grube, B; Grussenmeyer, T; Guskov, A; Haas, F; Hahne, D; von Harrach, D; Hashimoto, R; Heinsius, F H; Herrmann, F; Hinterberger, F; Horikawa, N; d'Hose, N; Hsieh, C-Yu; Huber, S; Ishimoto, S; Ivanov, A; Ivanshin, Yu; Iwata, T; Jahn, R; Jary, V; Jörg, P; Joosten, R; Kabuß, E; Ketzer, B; Khaustov, G V; Khokhlov, Yu A; Kisselev, Yu; Klein, F; Klimaszewski, K; Koivuniemi, J H; Kolosov, V N; Kondo, K; Königsmann, K; Konorov, I; Konstantinov, V F; Kotzinian, A M; Kouznetsov, O; Krämer, M; Kremser, P; Krinner, F; Kroumchtein, Z V; Kuchinski, N; Kunne, F; Kurek, K; Kurjata, R P; Lednev, A A; Lehmann, A; Levillain, M; Levorato, S; Lichtenstadt, J; Maggiora, A; Magnon, A; Makins, N; Makke, N; Mallot, G K; Marchand, C; Martin, A; Marzec, J; Matousek, J; Matsuda, H; Matsuda, T; Meshcheryakov, G; Meyer, W; Michigami, T; Mikhailov, Yu V; Miyachi, Y; Nagaytsev, A; Nagel, T; Nerling, F; Neyret, D; Nikolaenko, V I; Novy, J; Nowak, W-D; Nunes, A S; Olshevsky, A G; Orlov, I; Ostrick, M; Panzieri, D; Parsamyan, B; Paul, S; Peng, J-C; Pereira, F; Pesek, M; Peshekhonov, D V; Platchkov, S; Pochodzalla, J; Polyakov, V A; Pretz, J; Quaresma, M; Quintans, C; Ramos, S; Regali, C; Reicherz, G; Riedl, C; Rocco, E; Rossiyskaya, N S; Ryabchikov, D I; Rychter, A; Samoylenko, V D; Sandacz, A; Santos, C; Sarkar, S; Savin, I A; Sbrizzai, G; Schiavon, P; Schmeing, S; Schmidt, K; Schmieden, H; Schönning, K; Schopferer, S; Schlüter, T; Selyunin, A; Shevchenko, O Yu; Silva, L; Sinha, L; Sirtl, S; Slunecka, M; Sozzi, F; Srnka, A; Stolarski, M; Sulc, M; Suzuki, H; Szabelski, A; Szameitat, T; Sznajder, P; Takekawa, S; Ter Wolbeek, J; Tessaro, S; Tessarotto, F; Thibaud, F; Tskhay, V; Uhl, S; Veloso, J; Virius, M; Wallner, S; Weisrock, T; Wilfert, M; Zaremba, K; Zavertyaev, M; Zemlyanichkina, E; Ziembicki, M; Zink, A

    2015-08-21

    The COMPASS Collaboration at CERN has measured diffractive dissociation of 190  GeV/c pions into the π(-)π(-)π(+) final state using a stationary hydrogen target. A partial-wave analysis (PWA) was performed in bins of 3π mass and four-momentum transfer using the isobar model and the so far largest PWA model consisting of 88 waves. A narrow peak is observed in the f0(980)π channel with spin, parity and C-parity quantum numbers J(PC)=1(++). We present a resonance-model study of a subset of the spin-density matrix selecting 3π states with J(PC)=2(++) and 4(++) decaying into ρ(770)π and with J(PC)=1(++) decaying into f0(980)π. We identify a new a1 meson with mass (1414(-13)(+15))  MeV/c2 and width (153(-23)(+8))  MeV/c2. Within the final states investigated in our analysis, we observe the new a1(1420) decaying only into f0(980)π, suggesting its exotic nature. PMID:26340182

  13. Measurement of the Neutrino Neutral-Current Elastic Differential Cross Section

    SciTech Connect

    Aguilar-Arevalo, A.A.; Anderson, C.E.; Bazarko, A.O.; Brice, S.J.; Brown, B.C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J.M.; Cox, D.C.; Curioni, A.; /Yale U. /Argonne

    2010-07-01

    We report a measurement of the flux-averaged neutral-current elastic differential cross section for neutrinos scattering on mineral oil (CH{sub 2}) as a function of four-momentum transferred squared, Q{sup 2}. It is obtained by measuring the kinematics of recoiling nucleons with kinetic energy greater than 50 MeV which are readily detected in MiniBooNE. This differential cross-section distribution is fit with fixed nucleon form factors apart from an axial mass, M{sub A}, that provides a best fit for M{sub A} = 1.39 {+-} 0.11 GeV. Using the data from the charged-current neutrino interaction sample, a ratio of neutral-current to charged-current quasi-elastic cross sections as a function of Q{sup 2} has been measured. Additionally, single protons with kinetic energies above 350 MeV can be distinguished from neutrons and multiple nucleon events. Using this marker, the strange quark contribution to the neutral-current axial vector form factor at Q{sup 2} = 0, {Delta}s, is found to be {Delta}s = 0.08{+-} 0.26.

  14. a Measurement of the Asymmetry Parameter for Argon -35 Beta-Decay as a Test of the Conserved Vector Current Hypothesis

    NASA Astrophysics Data System (ADS)

    Converse, Alexander Milovan

    The spatial asymmetry of positrons emitted parallel and antiparallel to the spin axis of a polarized sample of ^{35}Ar has been measured. The measured asymmetry parameter for the mixed Fermi--Gamow - Teller decay ^{35}Ar( beta^+)^{35}Cl is A_0 = 0.427(23). This agrees with the value predicted by the Standard Model, A _0^{rm theory} = 0.4302(86). The Standard Model prediction assumes vector-axial vector couplings and the validity of the conserved vector current hypothesis; the vector coupling strength is derived from comparative half-lives of pure Fermi 0^+to0^+ transitions, and the ratio of axial vector to vector coupling strengths is calculated using the ^ {35}Ar comparative half-life. In the measurement, polarized ^{35}Ar was created by bombarding a Cl_2 target with 68% polarized 9.2 MeV protons. Positrons emitted at 0^circ and 180 ^circ with respect to the ^{35}Ar polarization axis were observed with DeltaE-E plastic scintillator detectors. The ^{35}Ar polarization was determined from the asymmetry of positrons emitted in the decays ^{35}Ar( beta^+)^{35}Cl ^*, which were identified by the observation of coincident gamma - rays in pure Ge detectors. The decay to the first excited state of ^{35}Cl is pure Gamow - Teller, so its asymmetry parameter may be derived from angular momentum coupling arguments without reference to the Standard Model. The relative uncertainty in this measurement, DeltaA_0 /A_0 = 5.4%, is the quadratic sum of the statistical error, 5.4%, and systematic errors, 0.5%. In light of published measurements of the neutron asymmetry parameter, which are accurate to 1.5% and disagree with the Standard Model prediction by more than 2 sigma, it might be worthwhile to repeat the measurement of the ^{35}Ar ground state asymmetry parameter to obtain statistical precision of <2%.

  15. Uncertainty Quantification for Nuclear Currents: A Bayesian χ-EFT view of the Triton and β- Decay

    NASA Astrophysics Data System (ADS)

    Wendt, Kyle

    2014-09-01

    Chiral Effective Field Theory (χ-EFT) provides a framework for the generation and systematic improvement of model independent inter-nucleon interaction Hamiltonians and nuclear current operators. Within χ-EFT, short and mid distance physics is encoded through a gradient expansion and multiple pion exchange parameterized by a set of low energy constants (LECs). The LECs are often constrained via non-linear least squares using nuclear bound state and scattering observables. This has produced reasonable low-energy descriptions in the past, but has been plagued by LECs that are unnaturally large. Additional issues manifest in medium mass nuclei where the χ-EFT Hamiltonians fail to adequately describe saturation properties. It has been suggested that Bayesian approaches may remedy the unnaturally large LECs using carefully selected priors. Other analyses have suggested that the inclusion and feedback of nuclear currents into the constraints of the LECs may improve saturation properties. We combine these approaches using Markov chain Monte Carlo (MCMC) to study and quantify uncertainties in the Triton and the χ-EFT axial-vector current, with the aim of providing a foundation for quantifying χ-EFT uncertainties for weak processes in nuclei. Chiral Effective Field Theory (χ-EFT) provides a framework for the generation and systematic improvement of model independent inter-nucleon interaction Hamiltonians and nuclear current operators. Within χ-EFT, short and mid distance physics is encoded through a gradient expansion and multiple pion exchange parameterized by a set of low energy constants (LECs). The LECs are often constrained via non-linear least squares using nuclear bound state and scattering observables. This has produced reasonable low-energy descriptions in the past, but has been plagued by LECs that are unnaturally large. Additional issues manifest in medium mass nuclei where the χ-EFT Hamiltonians fail to adequately describe saturation properties. It has

  16. Coherent production of pions and rho mesons in neutrino charged current interactions on neon nuclei at the Fermilab Tevatron

    SciTech Connect

    Willocq, S.

    1992-05-01

    The coherent production of single pions and and {rho} mesons in charged current interactions of neutrinos and antineutrinos on neon nuclei has been studied. The data were obtained using the Fermilab 15-foot Bubble Chamber, filled with a heavy Ne-H{sub 2} mixture and exposed to the Quadrupole Triplet neutrino beam produced by 800 GeV protons from the Tevatron. The average beam energy was 86 GeV. In a sample of 330000 frames, 1032 two-prong {nu}{sub {mu}} + {bar {nu}}{sub {mu}} charged current interactions were selected. The goal of this study was to investigate the low Q{sup 2} high {nu} region where the hadron dominance model can be tested. In this model, the vector and axial-vector parts of the weak hadronic current are dominated by the {rho} and a{sub 1} mesons respectively. Moreover, the Partially Conserved Axial Current (PCAC) hypothesis can be tested by studying the coherent production of single pions.

  17. Measurement of the neutrino neutral-current elastic differential cross section on mineral oil at E{sub {nu}{approx}1} GeV

    SciTech Connect

    Aguilar-Arevalo, A. A.; Cao, J.; Anderson, C. E.; Curioni, A.; Fleming, B. T.; Linden, S. K.; Soderberg, M.; Spitz, J.; Bazarko, A. O.; Laird, E. M.; Meyers, P. D.; Patterson, R. B.; Shoemaker, F. C.; Tanaka, H. A.; Brice, S. J.; Brown, B. C.; Finley, D. A.; Ford, R.; Garcia, F. G.; Kasper, P.

    2010-11-01

    We report a measurement of the flux-averaged neutral-current elastic differential cross section for neutrinos scattering on mineral oil (CH{sub 2}) as a function of four-momentum transferred squared, Q{sup 2}. It is obtained by measuring the kinematics of recoiling nucleons with kinetic energy greater than 50 MeV which are readily detected in MiniBooNE. This differential cross-section distribution is fit with fixed nucleon form factors apart from an axial mass M{sub A} that provides a best fit for M{sub A}=1.39{+-}0.11 GeV. Using the data from the charged-current neutrino interaction sample, a ratio of neutral-current to charged-current quasielastic cross sections as a function of Q{sup 2} has been measured. Additionally, single protons with kinetic energies above 350 MeV can be distinguished from neutrons and multiple nucleon events. Using this marker, the strange quark contribution to the neutral-current axial vector form factor at Q{sup 2}=0, {Delta}s, is found to be {Delta}s=0.08{+-}0.26.

  18. Measurement of the neutrino neutral-current elastic differential cross section on mineral oil at Eν˜1GeV

    NASA Astrophysics Data System (ADS)

    Aguilar-Arevalo, A. A.; Anderson, C. E.; Bazarko, A. O.; Brice, S. J.; Brown, B. C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J. M.; Cox, D. C.; Curioni, A.; Dharmapalan, R.; Djurcic, Z.; Finley, D. A.; Fleming, B. T.; Ford, R.; Garcia, F. G.; Garvey, G. T.; Grange, J.; Green, C.; Green, J. A.; Hart, T. L.; Hawker, E.; Imlay, R.; Johnson, R. A.; Karagiorgi, G.; Kasper, P.; Katori, T.; Kobilarcik, T.; Kourbanis, I.; Koutsoliotas, S.; Laird, E. M.; Linden, S. K.; Link, J. M.; Liu, Y.; Liu, Y.; Louis, W. C.; Mahn, K. B. M.; Marsh, W.; Mauger, C.; McGary, V. T.; McGregor, G.; Metcalf, W.; Meyers, P. D.; Mills, F.; Mills, G. B.; Monroe, J.; Moore, C. D.; Mousseau, J.; Nelson, R. H.; Nienaber, P.; Nowak, J. A.; Osmanov, B.; Ouedraogo, S.; Patterson, R. B.; Pavlovic, Z.; Perevalov, D.; Polly, C. C.; Prebys, E.; Raaf, J. L.; Ray, H.; Roe, B. P.; Russell, A. D.; Sandberg, V.; Schirato, R.; Schmitz, D.; Shaevitz, M. H.; Shoemaker, F. C.; Smith, D.; Soderberg, M.; Sorel, M.; Spentzouris, P.; Spitz, J.; Stancu, I.; Stefanski, R. J.; Sung, M.; Tanaka, H. A.; Tayloe, R.; Tzanov, M.; van de Water, R. G.; Wascko, M. O.; White, D. H.; Wilking, M. J.; Yang, H. J.; Zeller, G. P.; Zimmerman, E. D.

    2010-11-01

    We report a measurement of the flux-averaged neutral-current elastic differential cross section for neutrinos scattering on mineral oil (CH2) as a function of four-momentum transferred squared, Q2. It is obtained by measuring the kinematics of recoiling nucleons with kinetic energy greater than 50 MeV which are readily detected in MiniBooNE. This differential cross-section distribution is fit with fixed nucleon form factors apart from an axial mass MA that provides a best fit for MA=1.39±0.11GeV. Using the data from the charged-current neutrino interaction sample, a ratio of neutral-current to charged-current quasielastic cross sections as a function of Q2 has been measured. Additionally, single protons with kinetic energies above 350 MeV can be distinguished from neutrons and multiple nucleon events. Using this marker, the strange quark contribution to the neutral-current axial vector form factor at Q2=0, Δs, is found to be Δs=0.08±0.26.

  19. Four Momentum Transfer Discrepancy in the Charged Current pi+ Production in the MiniBooNE: Data versus Theory

    SciTech Connect

    Nowak, Jaroslaw A.; /Louisiana State U.

    2009-09-01

    The MiniBooNE experiment has collected what is currently the world's largest sample of {nu}{sub {mu}} charged current single charged pion (CCl{pi}{sup +}) interactions, roughly 46,000 events. The purity of the CCl{pi}{sup +} sample is 87% making this the purest event sample observed in the MiniBooNE detector. The average energy of neutrinos producing CC{pi}{sup +} interactions in MiniBooNE is about 1 GeV, therefore the study of these events can provide insight into both resonant and coherent pion production processes. In this talk, we will discuss the long-standing discrepancy in four-momentum transfer observed between CC{pi}{sup +} data and existing predictions. Several attempts to address this problem will be presented. Specifically, the Rein-Sehgal model has been extended to include muon mass terms for both resonant and coherent production. Using calculations from, an updated form for the vector form factor has also been adopted. The results of this improved description of CC{pi}{sup +} production will be compared to the high statistics MiniBooNE CC{pi}{sup +} data and several existing parametrizations of the axial vector form factor.

  20. Current sensor

    DOEpatents

    Yakymyshyn, Christopher Paul; Brubaker, Michael Allen; Yakymyshyn, Pamela Jane

    2007-01-16

    A current sensor is described that uses a plurality of magnetic field sensors positioned around a current carrying conductor. The sensor can be hinged to allow clamping to a conductor. The current sensor provides high measurement accuracy for both DC and AC currents, and is substantially immune to the effects of temperature, conductor position, nearby current carrying conductors and aging.

  1. Current limiters

    SciTech Connect

    Loescher, D.H.; Noren, K.

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  2. Gravity Currents

    NASA Astrophysics Data System (ADS)

    Simpson, John E.

    1997-03-01

    This book comprehensively describes all aspects of gravity flow, a physical process in the environment that is covered by many disciplines including meteorology, oceanography, the earth sciences and industrial processes. The first edition was very well received, and the author has brought the new edition completely up to date, with much new material. Simpson describes gravity currents with a variety of laboratory experiments, many from his own work. Gravity Currents is a valuable supplementary textbook for undergraduates and a reference work for research workers. The general reader will also find much of interest, since the author clearly describes the physics of flows involved without advanced mathematics, and with numerous photographs and illustrations.

  3. Gravity Currents

    NASA Astrophysics Data System (ADS)

    Simpson, John E.

    1999-11-01

    This book comprehensively describes all aspects of gravity flow, a physical process in the environment that is covered by many disciplines including meteorology, oceanography, the earth sciences and industrial processes. The first edition was very well received, and the author has brought the new edition completely up to date, with much new material. Simpson describes gravity currents with a variety of laboratory experiments, many from his own work. Gravity Currents is a valuable supplementary textbook for undergraduates and a reference work for research workers. The general reader will also find much of interest, since the author clearly describes the physics of flows involved without advanced mathematics, and with numerous photographs and illustrations.

  4. Current Titles

    SciTech Connect

    Various

    2006-06-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Jane Cavlina, Administrator, at 510/486-6036.

  5. Current titles

    SciTech Connect

    1995-07-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Gretchen Hermes at (510) 486-5006 or address below for a User`s Guide. Copies of available papers can be ordered from: Theda Crawford National Center for Electron Microscopy, Lawrence Berkeley Laboratory, One Cyclotron Rd., MS72, Berkeley, California, USA 94720.

  6. Current awareness

    PubMed

    Green; Feher; Catalan

    2000-07-01

    In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of diabetes/metabolism. Each bibliography is divided into 17 sections: 1 Books, Reviews & Symposia; 2 General; 3 Genetics; 4 Epidemiology; 5 Immunology; 6 Prediction; 7 Prevention; 8 Intervention: a&rpar General; b&rpar Pharmacology; 9 Pathology: a&rpar General; b&rpar Cardiovascular; c&rpar Neurological; d&rpar Renal; 10 Endocrinology & Metabolism; 11 Nutrition; 12 Animal Studies; 13 Techniques. Within each section, articles are listed in alphabetical order with respect to author (8 Weeks journals - Search completed at 19th Apr. 2000) PMID:10934459

  7. Measurement of the β-asymmetry parameter of Cu67 in search for tensor-type currents in the weak interaction

    NASA Astrophysics Data System (ADS)

    Soti, G.; Wauters, F.; Breitenfeldt, M.; Finlay, P.; Herzog, P.; Knecht, A.; Köster, U.; Kraev, I. S.; Porobic, T.; Prashanth, P. N.; Towner, I. S.; Tramm, C.; Zákoucký, D.; Severijns, N.

    2014-09-01

    Background: Precision measurements at low energy search for physics beyond the standard model in a way complementary to searches for new particles at colliders. In the weak sector the most general β-decay Hamiltonian contains, besides vector and axial-vector terms, also scalar, tensor, and pseudoscalar terms. Current limits on the scalar and tensor coupling constants from neutron and nuclear β decay are on the level of several percent. Purpose: Extracting new information on tensor coupling constants by measuring the β-asymmetry parameter in the pure Gamow-Teller decay of Cu67, thereby testing the V-A structure of the weak interaction. Method: An iron sample foil into which the radioactive nuclei were implanted was cooled down to mK temperatures in a 3He-4He dilution refrigerator. An external magnetic field of 0.1 T, in combination with the internal hyperfine magnetic field, oriented the nuclei. The anisotropic β radiation was observed with planar high-purity germanium detectors operating at a temperature of about 10 K. An on-line measurement of the β asymmetry of Cu68 was performed as well for normalization purposes. Systematic effects were investigated using geant4 simulations. Results: The experimental value, Ã=0.587(14), is in agreement with the standard model value of 0.5991(2) and is interpreted in terms of physics beyond the standard model. The limits obtained on possible tensor-type charged currents in the weak interaction Hamiltonian are -0.045<(CT+CT')/CA<0.159 (90% C.L.). Conclusions: The obtained limits are comparable to limits from other correlation measurements in nuclear β decay and contribute to further constraining tensor coupling constants.

  8. Flavor-spin symmetry estimate of the nucleon tensor charge.

    PubMed

    Gamberg, L; Goldstein, G R

    2001-12-10

    The axial vector and tensor charge, defined as the first moments of the forward nucleon matrix elements of corresponding quark currents, are essential for characterizing the spin structure of the nucleon. There are no definitive theoretical predictions for the tensor charge, aside from several model-dependent calculations. We present a new approach that exploits the approximate mass degeneracy of the light axial vector mesons [ a1(1260), b1(1235), and h1(1170)] and uses pole dominance to calculate the tensor charge. The result is simple in form. It depends on the decay constants of the axial vector mesons and their couplings to the nucleons. PMID:11736495

  9. Superconducting fault current controller/current controller

    DOEpatents

    Cha, Yung S.

    2004-06-15

    A superconducting fault current controller/current controller employs a superconducting-shielded core reactor (SSCR) with a variable impedance in a secondary circuit to control current in a primary circuit such as an electrical distribution system. In a second embodiment, a variable current source is employed in a secondary circuit of an SSCR to control current in the primary circuit. In a third embodiment, both a variable impedance in one secondary circuit and a variable current source in a second circuit of an SSCR are employed for separate and independent control of current in the primary circuit.

  10. Axial, induced pseudoscalar, and pion-nucleon form factors in manifestly Lorentz-invariant chiral perturbation theory

    SciTech Connect

    Schindler, M. R.; Fuchs, T.; Scherer, S.; Gegelia, J.

    2007-02-15

    We calculate the nucleon form factors G{sub A} and G{sub P} of the isovector axial-vector current and the pion-nucleon form factor G{sub {pi}}{sub N} in manifestly Lorentz-invariant baryon chiral perturbation theory up to and including order O(p{sup 4}). In addition to the standard treatment including the nucleon and pions, we also consider the axial-vector meson a{sub 1} as an explicit degree of freedom. This is achieved by using the reformulated infrared renormalization scheme. We find that the inclusion of the axial-vector meson effectively results in one additional low-energy coupling constant that we determine by a fit to the data for G{sub A}. The inclusion of the axial-vector meson results in an improved description of the experimental data for G{sub A}, while the contribution to G{sub P} is small.

  11. Weak neutral-current effects in e/sup +/e/sup -/. -->. mu. /sup +/. mu. /sup -/ at 29 GeV

    SciTech Connect

    Fernandez, E.; Ford, W.T.; Read, A.L. Jr.; Smith, J.G.; De Sangro, R.; Marini, A.; Peruzzi, I.; Piccolo, M.; Ronga, F.; Blume, H.T.

    1983-07-01

    We present a measurement of the cross section for production of collinear muon pairs based upon a sample of more than 10,000 events observed in the MAC detector at PEP. From the asymmetry A/sub ..mu mu.. = -0.058 +- 0.010 we find the axial vector weak neutral coupling to be given by g/sub A//sup e/g/sub A//sup ..mu../ = 0.24 +- 0.04.

  12. The current catalog--how current?

    PubMed

    Sargent, C W

    1968-07-01

    NLM's Current Catalog has recently come in for some criticism. To be useful as a tool in acquisition and cataloging, currency in receipt of the Current Catalog is necessary. A survey of 263 titles with 1967 imprints, which were received by the Library of the Medical Sciences, University of New Mexico School of Medicine, was made to determine the correlation between the receipt of these books in the library and their appearance in the Current Catalog. PMID:5695111

  13. Current measuring system

    DOEpatents

    Dahl, David A.; Appelhans, Anthony D.; Olson, John E.

    1997-01-01

    A current measuring system comprising a current measuring device having a first electrode at ground potential, and a second electrode; a current source having an offset potential of at least three hundred volts, the current source having an output electrode; and a capacitor having a first electrode electrically connected to the output electrode of the current source and having a second electrode electrically connected to the second electrode of the current measuring device.

  14. Current measuring system

    DOEpatents

    Dahl, D.A.; Appelhans, A.D.; Olson, J.E.

    1997-09-09

    A current measuring system is disclosed comprising a current measuring device having a first electrode at ground potential, and a second electrode; a current source having an offset potential of at least three hundred volts, the current source having an output electrode; and a capacitor having a first electrode electrically connected to the output electrode of the current source and having a second electrode electrically connected to the second electrode of the current measuring device. 4 figs.

  15. Welding-Current Indicator

    NASA Technical Reports Server (NTRS)

    Hensley, Milton C.; Huston, Steven W.; Kroy, Ralph E.

    1990-01-01

    Light flashes on to indicate high current. Simple, inexpensive display circuit indicates when 3,000-A welding current flows in welding gun. Onset of welding current induces voltage and current in 1,000-turn, 28-gauge copper-wire coil. Single-transistor amplifier amplifies induced current, energizing light-emitting diode (LED) connected to collector of transistor. Light from LED gives simple, direct indication of welding current.

  16. Current measurement apparatus

    DOEpatents

    Umans, Stephen D.

    2008-11-11

    Apparatus and methods are provided for a system for measurement of a current in a conductor such that the conductor current may be momentarily directed to a current measurement element in order to maintain proper current without significantly increasing an amount of power dissipation attributable to the current measurement element or adding resistance to assist in current measurement. The apparatus and methods described herein are useful in superconducting circuits where it is necessary to monitor current carried by the superconducting elements while minimizing the effects of power dissipation attributable to the current measurement element.

  17. A Study of Charged Current Single Charged Pion Productions on Carbon in a Few-GeV Neutrino Beam

    SciTech Connect

    Hiraide, Katsuki

    2009-01-01

    Understanding single charged pion production via neutrino-nucleus charged current interaction in the neutrino energy region of a few GeV is essential for future neutrino oscillation experiments since this process is a dominant background for vμ → vx oscillation measurements. There are two contributions to this process: single pion production via baryonic resonance (vμN → μ-+) and coherent pion production interacting with the entire nucleus (vμA → μ-+), where N is nucleon in the nucleus and A is the nucleus. The purpose of the study presented in this thesis is a precise measurement of charged current single charged pion productions, resonant and coherent pion productions, with a good final state separation in the neutrino energy region of a few GeV. In this thesis, we focus on the study of charged current coherent pion production from muon neutrinos scattering on carbon, vμ 12C → μ-12+, in the SciBooNE experiment. This is motivated by the fact that without measuring this component first, the precise determination of resonant pion production cross section can not be achieved since the contribution of coherent pion production in the region of small muon scattering angle is not small. Furthermore, the coherent process is particularly interesting because it is deeply rooted in fundamental physics via Adler's partially conserved axial-vector current theorem. We took data from June 2007 until August 2008, in both the neutrino and antineutrino beam. In total, 2.52 x 1020 protons on target were collected. We have performed a search for charged current coherent pion production by using SciBooNE's full neutrino data set, corresponding to 0.99 x 1020 protons on target. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio of charged

  18. LANSCE beam current limiter

    SciTech Connect

    Gallegos, F.R.

    1996-06-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described.

  19. LANSCE beam current limiter

    SciTech Connect

    Gallegos, F.R.

    1997-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the beam current limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beamline below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described. {copyright} {ital 1997 American Institute of Physics.}

  20. Anomalous - viscosity current drive

    DOEpatents

    Stix, Thomas H.; Ono, Masayuki

    1988-01-01

    An apparatus and method for maintaining a steady-state current in a toroidal magnetically confined plasma. An electric current is generated in an edge region at or near the outermost good magnetic surface of the toroidal plasma. The edge current is generated in a direction parallel to the flow of current in the main plasma and such that its current density is greater than the average density of the main plasma current. The current flow in the edge region is maintained in a direction parallel to the main current for a period of one or two of its characteristic decay times. Current from the edge region will penetrate radially into the plasma and augment the main plasma current through the mechanism of anomalous viscosity. In another aspect of the invention, current flow driven between a cathode and an anode is used to establish a start-up plasma current. The plasma-current channel is magnetically detached from the electrodes, leaving a plasma magnetically insulated from contact with any material obstructions including the cathode and anode.

  1. Magnetic current sensor

    NASA Technical Reports Server (NTRS)

    Black, Jr., William C. (Inventor); Hermann, Theodore M. (Inventor)

    1998-01-01

    A current determiner having an output at which representations of input currents are provided having an input conductor for the input current and a current sensor supported on a substrate electrically isolated from one another but with the sensor positioned in the magnetic fields arising about the input conductor due to any input currents. The sensor extends along the substrate in a direction primarily perpendicular to the extent of the input conductor and is formed of at least a pair of thin-film ferromagnetic layers separated by a non-magnetic conductive layer. The sensor can be electrically connected to a electronic circuitry formed in the substrate including a nonlinearity adaptation circuit to provide representations of the input currents of increased accuracy despite nonlinearities in the current sensor, and can include further current sensors in bridge circuits.

  2. Current focusing and steering

    PubMed Central

    Bonham, Ben H.; Litvak, Leonid M.

    2008-01-01

    Current steering and current focusing are stimulation techniques designed to increase the number of distinct perceptual channels available to cochlear implant (CI) users by adjusting currents applied simultaneously to multiple CI electrodes. Previous studies exploring current steering and current focusing stimulation strategies are reviewed, including results of research using computational models, animal neurophysiology, and human psychophysics. Preliminary results of additional neurophysiological and human psychophysical studies are presented that demonstrate the success of current steering strategies in stimulating auditory nerve regions lying between physical CI electrodes, as well as current focusing strategies that excite regions narrower than those stimulated using monopolar configurations. These results are interpreted in the context of perception and speech reception by CI users. Disparities between results of physiological and psychophysical studies are discussed. The differences in stimulation used for physiological and psychophysical studies are hypothesized to contribute to these disparities. Finally, application of current steering and focusing strategies to other types of auditory prostheses is also discussed. PMID:18501539

  3. DC current monitor

    NASA Technical Reports Server (NTRS)

    Canter, Stanley (Inventor)

    1991-01-01

    A non-intrusive DC current monitor is presented which emulates the theoretical operation of an AC transformer. A conductor, carrying the current to be measured, acts as the primary of a DC current transformer. This current is passed through the center of a secondary coil, and core positioned thereabout, and produces a magnetic flux which induces a current in the secondary proportional to the current flowing in the primary. Means are provided to periodically reset the transformer core such that the measurement inaccuracies associated with core saturation are obviated. A reset current is caused to periodically flow through the secondary coil which produces a magnetic flux oppositely polarized to the flux created by the current in the primary, thus allowing ongoing measurements to be made.

  4. 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…

  5. CIRCUITS FOR CURRENT MEASUREMENTS

    DOEpatents

    Cox, R.J.

    1958-11-01

    Circuits are presented for measurement of a logarithmic scale of current flowing in a high impedance. In one form of the invention the disclosed circuit is in combination with an ionization chamber to measure lonization current. The particular circuit arrangement lncludes a vacuum tube having at least one grid, an ionization chamber connected in series with a high voltage source and the grid of the vacuum tube, and a d-c amplifier feedback circuit. As the ionization chamber current passes between the grid and cathode of the tube, the feedback circuit acts to stabilize the anode current, and the feedback voltage is a measure of the logaritbm of the ionization current.

  6. Current enhancement update

    SciTech Connect

    Chambers, F.W.; Clark, J.C.; Struve, K.W.; Yu, S.S.

    1984-06-14

    Net current enhancement to levels in excess of the beam current has been observed in gases at pressures excess of 50 torr. We delineate the regimes where enhancement is observed. The experimental results fall into two very distinct classes; current enhancement at injection where the beam is only slightly displaced and current enhancement clearly associated with the high amplitude hose instability. A careful theoretical and experimental study of the diagnostics revealed no fundamental flaws although there are several complex and unlikely scenarios which could introduce fictitious current enhancement. Theoretical efforts indicate several mechanisms for generating enhancement but none of the theories can account for the detailed observations. 4 references, 4 figures.

  7. Inrush Current Control Circuit

    NASA Technical Reports Server (NTRS)

    Cole, Steven W. (Inventor)

    2002-01-01

    An inrush current control circuit having an input terminal connected to a DC power supply and an output terminal connected to a load capacitor limits the inrush current that charges up the load capacitor during power up of a system. When the DC power supply applies a DC voltage to the input terminal, the inrush current control circuit produces a voltage ramp at the load capacitor instead of an abrupt DC voltage. The voltage ramp results in a constant low level current to charge up the load capacitor, greatly reducing the current drain on the DC power supply.

  8. The plasma current multiplier

    NASA Astrophysics Data System (ADS)

    Shmayda, W. T.

    1981-11-01

    The Plasma Current Multiplier (PCM) is a well-stabilized low pressure arc discharge with the capability of multiplying the initial electron current injected into the device. Experimentally the PCM gain per unit length (g) was found to decrease with increasing arc current at very low arc current densities, to remain constant at moderate arc current densities, and to decrease asymptotically towards unity at extremely high current densities. Theoretically, sheath thickening and neutral rarefaction due to local gas heating have been identified as the phenomena responsible for the PCM gain behavior at the very low and high arc current densities respectively. Experimental confirmation of the gain dependence on mass and tube radius originally predicted by the Stangeby and Allen theory was extended to several atomic species. An emissionless source of electrons was constructed and tested, thus expanding the operating capacity of this device to reactive gases.

  9. Tsunami currents in ports.

    PubMed

    Borrero, Jose C; Lynett, Patrick J; Kalligeris, Nikos

    2015-10-28

    Tsunami-induced currents present an obvious hazard to maritime activities and ports in particular. The historical record is replete with accounts from ship captains and harbour masters describing their fateful encounters with currents and surges caused by these destructive waves. Despite the well-known hazard, only since the trans-oceanic tsunamis of the early twenty-first century (2004, 2010 and 2011) have coastal and port engineering practitioners begun to develop port-specific warning and response products that accurately assess the effects of tsunami-induced currents in addition to overland flooding and inundation. The hazard from strong currents induced by far-field tsunami remains an underappreciated risk in the port and maritime community. In this paper, we will discuss the history of tsunami current observations in ports, look into the current state of the art in port tsunami hazard assessment and discuss future research trends. PMID:26392622

  10. Electric current locator

    DOEpatents

    King, Paul E.; Woodside, Charles Rigel

    2012-02-07

    The disclosure herein provides an apparatus for location of a quantity of current vectors in an electrical device, where the current vector has a known direction and a known relative magnitude to an input current supplied to the electrical device. Mathematical constants used in Biot-Savart superposition equations are determined for the electrical device, the orientation of the apparatus, and relative magnitude of the current vector and the input current, and the apparatus utilizes magnetic field sensors oriented to a sensing plane to provide current vector location based on the solution of the Biot-Savart superposition equations. Description of required orientations between the apparatus and the electrical device are disclosed and various methods of determining the mathematical constants are presented.

  11. Measurement of Neutrino-Nucleon Neutral-Current Elastic Scattering Cross-section at SciBooNE

    SciTech Connect

    Takei, Hideyuki; /Tokyo Inst. Tech.

    2009-02-01

    In this thesis, results of neutrino-nucleon neutral current (NC) elastic scattering analysis are presented. Neutrinos interact with other particles only with weak force. Measurement of cross-section for neutrino-nucleon reactions at various neutrino energy are important for the study of nucleon structure. It also provides data to be used for beam flux monitor in neutrino oscillation experiments. The cross-section for neutrino-nucleon NC elastic scattering contains the axial vector form factor G{sub A}(Q{sup 2}) as well as electromagnetic form factors unlike electromagnetic interaction. G{sub A} is propotional to strange part of nucleon spin ({Delta}s) in Q{sup 2} {yields} 0 limit. Measurement of NC elastic cross-section with smaller Q{sup 2} enables us to access {Delta}s. NC elastic cross-sections of neutrino-nucleon and antineutrino-nucleon were measured earlier by E734 experiment at Brookheaven National Laboratory (BNL) in 1987. In this experiment, cross-sections were measured in Q{sup 2} > 0.4 GeV{sup 2} region. Result from this experiment was the only published data for NC elastic scattering cross-section published before our experiment. SciBooNE is an experiment for the measurement of neutrino-nucleon scattering cross-secitons using Booster Neutrino Beam (BNB) at FNAL. BNB has energy peak at 0.7 GeV. In this energy region, NC elastic scattering, charged current elastic scattering, charged current pion production, and neutral current pion production are the major reaction branches. SciBar, electromagnetic calorimeter, and Muon Range Detector are the detectors for SciBooNE. The SciBar consists of finely segmented scintillators and 14336 channels of PMTs. It has a capability to reconstruct particle track longer than 8 cm and separate proton from muons and pions using energy deposit information. Signal of NC elastic scattering is a single proton track. In {nu}p {yields} {nu}p process, the recoil proton is detected. On the other hand, most of {nu}n {yields} {nu

  12. Electric current solves mazes

    NASA Astrophysics Data System (ADS)

    Ayrinhac, Simon

    2014-07-01

    We present in this work a demonstration of the maze-solving problem with electricity. Electric current flowing in a maze as a printed circuit produces Joule heating and the right way is instantaneously revealed with infrared thermal imaging. The basic properties of electric current can be discussed in this context, with this challenging question: how can the electric current choose the right way and avoid dead ends?

  13. RF current sensor

    DOEpatents

    Moore, James A.; Sparks, Dennis O.

    1998-11-10

    An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

  14. Tokamak halo currents

    SciTech Connect

    Boozer, Allen H.

    2013-08-15

    A halo current flows for part of its path through the plasma edge and for part through the chamber walls and can be as large as tenths of the plasma current. The primary interest in halo currents is the large force that they can exert on machine components. Two discordant constraints are central to the theory: (1) Halo currents must produce the magnetic field distribution required to maintain plasma force balance—a distribution that depends on the two angular coordinates of a torus. (2) Halo currents must flow along the magnetic field lines in the plasma, which implies a dependence on a linear combination of the two angular coordinates—only one angular coordinate is free. The physics basis of these two constraints is explained as is their application to the calculation of the properties of halo currents, such as their broad toroidal spectrum. Existing codes could be used to (1) provide detailed comparisons with experiments to validate that the critical elements of physics are adequately included, (2) allow more complete predictions for future machines such as ITER, and (3) design shunts and resistive elements to ensure halo currents follow paths that are the least damaging to the machine. The physics of halo currents implies that it may be possible to feedback stabilize resistive wall modes beyond the ideal-wall limit.

  15. MISR Current Project Quality

    Atmospheric Science Data Center

    2014-10-01

    ... by older software versions may be of different quality than current products. It is important, therefore, to note that dates on quality ... Links to older quality statements are available from the current Quality Statement pages. For a thorough description of MISR software ...

  16. Electric Current Solves Mazes

    ERIC Educational Resources Information Center

    Ayrinhac, Simon

    2014-01-01

    We present in this work a demonstration of the maze-solving problem with electricity. Electric current flowing in a maze as a printed circuit produces Joule heating and the right way is instantaneously revealed with infrared thermal imaging. The basic properties of electric current can be discussed in this context, with this challenging question:…

  17. Ultracapacitor current collector

    DOEpatents

    Jerabek, Elihu Calfin; Mikkor, Mati

    2001-10-16

    An ultracapacitor having two solid, nonporous current collectors, two porous electrodes separating the collectors, a porous separator between the electrodes and an electrolyte occupying the pores in the electrodes and separator. At least one of the current collectors comprises a conductive metal substrate coated with a metal nitride, carbide or boride coating.

  18. Current level detector

    DOEpatents

    Kerns, Cordon R.

    1977-01-01

    A device is provided for detecting the current level of a DC signal. It includes an even harmonic modulator to which a reference AC signal is applied. The unknown DC signal acts on the reference AC signal so that the output of the modulator includes an even harmonic whose amplitude is proportional to the unknown DC current.

  19. Direct current transformer

    NASA Technical Reports Server (NTRS)

    Khanna, S. M.; Urban, E. W. (Inventor)

    1979-01-01

    A direct current transformer in which the primary consists of an elongated strip of superconductive material, across the ends of which is direct current potential is described. Parallel and closely spaced to the primary is positioned a transformer secondary consisting of a thin strip of magnetoresistive material.

  20. Voltage controlled current source

    DOEpatents

    Casne, Gregory M.

    1992-01-01

    A seven decade, voltage controlled current source is described for use in testing intermediate range nuclear instruments that covers the entire test current range of from 10 picoamperes to 100 microamperes. High accuracy is obtained throughout the entire seven decades of output current with circuitry that includes a coordinated switching scheme responsive to the input signal from a hybrid computer to control the input voltage to an antilog amplifier, and to selectively connect a resistance to the antilog amplifier output to provide a continuous output current source as a function of a preset range of input voltage. An operator controlled switch provides current adjustment for operation in either a real-time simulation test mode or a time response test mode.

  1. Pulsed eddy current testing

    NASA Astrophysics Data System (ADS)

    Workman, G. L.

    1980-10-01

    Since a large number of the procedures used for inspecting the external tank are concerned with determining flaws in welds, there is a need to develop an inspection technique, which can be automated, to determine flaws in welds and structures with complex geometries. Techniques whereby an eddy current is generated in a metallic material and the changes in the circuit parameters due to material differences are observed, were chosen as one possible approach. Pulsed eddy current and its relationship to multifrequency techniques is discussed as well as some preliminary results obtained from observing pulsed waveforms with apparatus and algorithms currently in use for ultrasonic testing of welds. It can be shown the pulsed eddy current techniques can provide similar results, can eliminate some of the noncritical parameters affecting the eddy current signals, and can facilitate in the detection of critical parameter such as flaws, subsurface voids, and corrosion.

  2. Bound charges and currents

    NASA Astrophysics Data System (ADS)

    Herczyński, Andrzej

    2013-03-01

    Bound charges and currents are among the conceptually challenging topics in advanced courses on electricity and magnetism. It may be tempting for students to believe that they are merely computational tools for calculating electric and magnetic fields in matter, particularly because they are usually introduced through abstract manipulation of integral identities, with the physical interpretation provided a posteriori. Yet these charges and currents are no less real than free charges and currents and can be measured experimentally. A simpler and more direct approach to introducing this topic, suggested by the ideas in the classic book by Purcell and emphasizing the physical origin of these phenomena, is proposed.

  3. Wave - current interactions

    NASA Astrophysics Data System (ADS)

    Shugan, I.; Hwung, Hwung-Hweng; Yang, Ray-Yeng

    2012-04-01

    The problem of wave interaction with current is still a big challenge in physical oceanography. In spite of numerous numbers of papers devoting to the analysis of the phenomenon some very strong effects are still waiting for its clear description. One of the problems here is the Benjamin-Feir instability in the presence of variable current. Modulation instability is one of the most ubiquitous types of instabilities in nature. In modern nonlinear physics, it is considered as a basic process that classifies the qualitative behavior of modulated waves (``envelope waves'') and may initialize the formation of stable entities such as envelope solitons. We theoretically describe the explosion instability of waves on the adverse blocking current and corresponding frequency downshifting. Waves can be blocked only partly and overpass the opposite current barrier at the lower side band resonance frequency. Theoretical results are compared with available experiments.

  4. Current control circuitry

    DOEpatents

    Taubman, Matthew S.

    2005-03-15

    Among the embodiments of the present invention is an apparatus that includes a transistor (30), a servo device (40), and a current source (50). The servo device (40) is operable to provide a common base mode of operation of the transistor (30) by maintaining an approximately constant voltage level at the transistor base (32b). The current source (150) is operable to provide a bias current to the transistor (30). A first device (24) provides an input signal to an electrical node (70) positioned between the emitter (32e) of the transistor (30) and the current source (50). A second device (26) receives an output signal from the collector (32c) of the transistor (30).

  5. CURRENT TRANSFER SYSTEMS

    DOEpatents

    Watt, D.A.

    1956-07-01

    A current transfer system is described for transferring current between a rotating member and a co-axial stationary member. The particular area of application for the invention is in connection with homopolar generators where a low voltage and high current are generated. The current tramsfer system of the invention comprises a rotor member and a co-axial stator member wherein one of the members is shaped to provide a circumferential surface concave in section and the other member is shaped to have a peripheral portion in close proximity to the surface, whereby a liquid metal can be stably supported between the two members when they are moving relative to one another to establish an electrical conducting path between the members.

  6. Rossby rip currents

    NASA Astrophysics Data System (ADS)

    Marshall, David P.; Vogel, Bendix; Zhai, Xiaoming

    2013-08-01

    Oceanic Rossby waves and eddies flux energy and fluid westward, the latter through the Stokes drift or bolus transport. While the wave energy is largely dissipated at the western boundary, mass conservation requires that the fluid be returned offshore through Rossby rip currents. The form and magnitude of these rip currents are investigated through linear Rossby wave theory, a nonlinear numerical model, and analysis of sea surface height satellite observations. The net eastward volume transport by Rossby rip currents over the global ocean is estimated to be of order 10 Sv (1 Sv ≡106 m3 s-1). In an eddying ocean, both the westward Stokes drift and eastward rip currents can assume the form of banded quasi-zonal jets.

  7. [Current pharmacotherapy in migraine].

    PubMed

    Csépány, Éva; Magyar, Máté; Gyüre, Tamás; Bozsik, György; Ertsey, Csaba

    2015-12-01

    The exact pathomechanism of migraine is still unknown, currently there are no biomarkers for migraine diagnosis, and current animal models reflect only one aspect of migraine, therefore future migraine studies are necessary. The current treatment of migraine (both acute and preventive) is suboptimal. There are no specific preventive drugs for migraine, and current preventatives may become inefficient during long-term use. Triptans are useful abortive drugs, but not effective in some of the patients; severe cardio-or cerebrovascular side effects may occur. Triptans and ergot alkaloids (and also non-specific abortive agents) can cause medication overuse headache. A number of newly synthesized experimental drugs seem to be effective and promising for migraine therapy, but at present our experience with these is limited, therefore further studies are essential. PMID:26727720

  8. Eddy-current testing

    NASA Technical Reports Server (NTRS)

    Pasley, R. L.; Birdwell, J. A.

    1973-01-01

    Eddy-current inspection is discussed as a method for locating subsurface flaws in electrically conductive materials. The physical principles and electrical circuitry are described along with the test equipment.

  9. Geothermal Energy: Current abstracts

    SciTech Connect

    Ringe, A.C.

    1988-02-01

    This bulletin announces the current worldwide information available on the technologies required for economic recovery of geothermal energy and its use as direct heat or for electric power production. (ACR)

  10. Beam current sensor

    DOEpatents

    Kuchnir, Moyses; Mills, Frederick E.

    1987-01-01

    A current sensor for measuring the DC component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivites in the nano-ampere range.

  11. Beam current sensor

    DOEpatents

    Kuchnir, M.; Mills, F.E.

    1984-09-28

    A current sensor for measuring the dc component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivities in the nano-ampere range.

  12. Superconducting current transducer

    SciTech Connect

    Kuchnir, M.; Ozelis, J.P.

    1990-10-01

    The construction and performance of an electric current meter that operates in liquid He and mechanically splits apart to permit replacement of the current carrying conductor is described. It permits the measurement of currents induced in a loop of superconducting cable and expeditious exchange of such loops. It is a key component for a short sample cable testing facility that requires no high current power supplies nor high current leads. Its superconducting pickup circuit involves a non-magnetic core toroidal split-coil that surrounds the conductor and a solenoid whose field is sensed by a Hall probe. This toroidal split-coil is potted inside another compensating toroidal split-coil. The C shaped half toroids can be separated and brought precisely together from outside the cryostat. The Hall probe is energized and sensed by a lock-in amplifier whose output drives a bipolar power supply which feeds the compensating coil. The output is the voltage across a resistor in this feedback circuit. Currents of up to 10 kA can be measured with a precision of 150 mA. 3 refs., 4 figs.

  13. Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment.

    SciTech Connect

    D. Androic, D. S. Armstrong, J. Arvieux†, S. L. Bailey, D. H. Beck, E. J. Beise, J. Benesch,; F. Benmokhtar, L. Bimbot, J. Birchall, P. Bosted, H. Breuer, C. L. Capuano, Y.-C. Chao, A. Coppens,; C. A. Davis, C. Ellis, G. Flores, G. Franklin, C. Furget, D. Gaskell, M. T. W. Gericke, J. Grames,; G. Guillard, J. Hansknecht, T. Horn, M. Jones, P. M. King, W. Korsch, S. Kox, L. Lee, J. Liu,; A. Lung, J. Mammei, J. W. Martin, R. D. McKeown, M. Mihovilovic, A. Micherdzinska, H. Mkrtchyan, M. Muether, S. A. Page, V. Papavassiliou, S. F. Pate, S. K. Phillips, P. Pillot, M. L. Pitt, M. Poelker, B. Quinn, W. D. Ramsay, J.-S. Real, J. Roche, P. Roos, J. Schaub, T. Seva, N. Simicevic, G. R. Smith, D. T. Spayde, M. Stutzman, R. Suleiman, V. Tadevosyan, W. T. H. van Oers, M. Versteegen, E. Voutier, W. Vulcan, S. P. Wells, S. E. Williamson, S.A. Wood

    2010-01-01

    We have measured parity-violating asymmetries in elastic electron-proton and quasielastic electron-deuteron scattering at Q2=0.22 and 0.63 GeV2. They are sensitive to strange quark contributions to currents in the nucleon and the nucleon axial-vector current. The results indicate strange quark contributions of ≲10% of the charge and magnetic nucleon form factors at these four-momentum transfers. We also present the first measurement of anapole moment effects in the axial-vector current at these four-momentum transfers.

  14. Adjustable direct current and pulsed circuit fault current limiter

    DOEpatents

    Boenig, Heinrich J.; Schillig, Josef B.

    2003-09-23

    A fault current limiting system for direct current circuits and for pulsed power circuit. In the circuits, a current source biases a diode that is in series with the circuits' transmission line. If fault current in a circuit exceeds current from the current source biasing the diode open, the diode will cease conducting and route the fault current through the current source and an inductor. This limits the rate of rise and the peak value of the fault current.

  15. Micromagnetics with eddy currents

    NASA Astrophysics Data System (ADS)

    Iyer, R.; Millhollon, J.; Long, K.

    2011-01-01

    In this paper, we study the modified Landau-Lifshitz-Gilbert (LLG) equation for of a conducting, magnetic body. The modified LLG equations include the magnetic field due to eddy currents in the total effective magnetic field. We derive an expression for the magnetic field due to eddy current losses and show that it is well defined. We then show that the work done by the eddy currents in opposing the change of magnetization is a Rayleigh type dissipation function, and derive the modified LLG equations using the calculus of variations. Finally, we show that the modified LLG equations lead to a decrease in the Gibbs energy. This implies that the LLG equations describes a dynamic process proceeding spontaneously forward in time.

  16. FAST ACTING CURRENT SWITCH

    DOEpatents

    Batzer, T.H.; Cummings, D.B.; Ryan, J.F.

    1962-05-22

    A high-current, fast-acting switch is designed for utilization as a crowbar switch in a high-current circuit such as used to generate the magnetic confinement field of a plasma-confining and heat device, e.g., Pyrotron. The device particularly comprises a cylindrical housing containing two stationary, cylindrical contacts between which a movable contact is bridged to close the switch. The movable contact is actuated by a differential-pressure, airdriven piston assembly also within the housing. To absorb the acceleration (and the shock imparted to the device by the rapidly driven, movable contact), an adjustable air buffer assembly is provided, integrally connected to the movable contact and piston assembly. Various safety locks and circuit-synchronizing means are also provided to permit proper cooperation of the invention and the high-current circuit in which it is installed. (AEC)

  17. Eddy current damper

    NASA Technical Reports Server (NTRS)

    Ellis, R. C.; Fink, R. A.; Rich, R. W.

    1989-01-01

    A high torque capacity eddy current damper used as a rate limiting device for a large solar array deployment mechanism is discussed. The eddy current damper eliminates the problems associated with the outgassing or leaking of damping fluids. It also provides performance advantages such as damping torque rates, which are truly linear with respect to input speed, continuous 360 degree operation in both directions of rotation, wide operating temperature range, and the capability of convenient adjustment of damping rates by the user without disassembly or special tools.

  18. Current signature sensor

    NASA Technical Reports Server (NTRS)

    Perotti, Jose M. (Inventor); Lucena, Angel (Inventor); Ihlefeld, Curtis (Inventor); Burns, Bradley (Inventor); Bassignani, Karin E. (Inventor)

    2005-01-01

    A solenoid health monitoring system uses a signal conditioner and controller assembly in one embodiment that includes analog circuitry and a DSP controller. The analog circuitry provides signal conditioning to the low-level raw signal coming from a signal acquisition assembly. Software running in a DSP analyzes the incoming data (recorded current signature) and determines the state of the solenoid whether it is energized, de-energized, or in a transitioning state. In one embodiment, the software identifies key features in the current signature during the transition phase and is able to determine the health of the solenoid.

  19. Lightning current detector

    NASA Technical Reports Server (NTRS)

    Livermore, S. F. (Inventor)

    1978-01-01

    An apparatus for measuring the intensity of current produced in an elongated electrical conductive member by a lightning strike for determining the intensity of the lightning strike is presented. The apparatus includes an elongated strip of magnetic material that is carried within an elongated tubular housing. A predetermined electrical signal is recorded along the length of said elongated strip of magnetic material. One end of the magnetic material is positioned closely adjacent to the electrically conductive member so that the magnetic field produced by current flowing through said electrically conductive member disturbs a portion of the recorded electrical signal directly proportional to the intensity of the lightning strike.

  20. Current Signature Sensor

    NASA Technical Reports Server (NTRS)

    Perotti, Jose M. (Inventor); Lucena, Angel (Inventor); Ihlefeld, Curtis (Inventor); Burns, Bradley (Inventor); Bassignani, Mario (Inventor); Bassignani, Karin E. (Inventor)

    2005-01-01

    A solenoid health monitoring system uses a signal conditioner and controller assembly in one embodiment that includes analog circuitry and a DSP controller. The analog circuitry provides signal conditioning to the low-level raw signal coming from a signal acquisition assembly. Software running in a DSP analyzes the incoming data (recorded current signature) and determines the state of the solenoid whether it is energized, de-energized, or in a transitioning state. In one embodiment, the software identifies key features in the current signature during the transition phase and is able to determine the health of the solenoid.

  1. Fault current limiter

    DOEpatents

    Darmann, Francis Anthony

    2013-10-08

    A fault current limiter (FCL) includes a series of high permeability posts for collectively define a core for the FCL. A DC coil, for the purposes of saturating a portion of the high permeability posts, surrounds the complete structure outside of an enclosure in the form of a vessel. The vessel contains a dielectric insulation medium. AC coils, for transporting AC current, are wound on insulating formers and electrically interconnected to each other in a manner such that the senses of the magnetic field produced by each AC coil in the corresponding high permeability core are opposing. There are insulation barriers between phases to improve dielectric withstand properties of the dielectric medium.

  2. Feedback cooling of currents

    NASA Astrophysics Data System (ADS)

    Washburn, Sean

    1989-02-01

    Just as feedback can be used to correct errors in the output voltages of amplifiers, it can also be used to remove noise from the current through a resistor. Such a feedback amplifier behaves as a refrigerator cooling the electrons in a resistor connnected to it. This principle has been recognized since the 1940s but has been largely ignored because the cooling power available from such refrigerators is miniscule. It is pointed out here that the method might be practical for cooling the currents in the microscopic circuits that are typical of modern electrical engineering and recent studies in transport physics.

  3. Weak quark couplings induced by gluon corrections

    NASA Astrophysics Data System (ADS)

    Gavela, M. B.; Le Yaouanc, A.; Oliver, L.; Pène, O.; Raynal, J. C.

    1980-12-01

    We compute the quark couplings in flavor-changing semileptonic transitions induced by lowest-order gluon corrections. We investigate the consequences of these radiative corrections for the quark axial-vector coupling, the deviations from Cabibbo universality for the axial-vector relative to the vector current, and the induced couplings (first-class pseudoscalar and anomalous magnetic moment, and second-class scalar and pseudotensor). The correction lowers the axial-vector coupling and increases the magnetic moment. We study the dependence of the couplings on the quark mass difference. Some of these results, true to all orders in αs, generalize the theorem of Ademollo and Gatto. The effective current is pure V-A to a very good approximation for transitions of heavy quarks (m>~5 GeV).

  4. Current Issues in Dyslexia.

    ERIC Educational Resources Information Center

    Ansara, Alice, Ed.

    1979-01-01

    This bulletin is published annually in the interest of children with learning disabilities, language disabilities, or dyslexia. The 22 articles discuss the following topics: current issues in dyslexia, language disorders, subgroups in dyslexia, specificity and parameters in defining dyslexia, strategies for recognition and management of reading…

  5. Keeping Science Current.

    ERIC Educational Resources Information Center

    Timmerman, Barbara

    2002-01-01

    Points out old-dated information provided in textbooks and recommends using current events to close the knowledge gap between the real world and textbooks. Uses year-long journal writings in which students choose a science article and analyze it. Provides an example of the activity sheet. (YDS)

  6. Reading Current Events Items.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    People who live in a democracy should be well informed of local, state, national, and international happenings. Students should become curious about news items and relate current happenings to the personal self. They must possess skills in word recognition and in diverse kinds of comprehension since reading is an important way to glean current…

  7. HIV Disease: Current Concepts.

    ERIC Educational Resources Information Center

    Keeling, Richard P.

    1993-01-01

    Describes human immunodeficiency virus (HIV), newly characterized human retrovirus which causes chronic, progressive, immune deficiency disease, the most severe phase of which is Acquired Immune Deficiency Syndrome (AIDS). Reviews most important current epidemiologic, clinical, and virologic information about HIV and HIV disease and provides…

  8. Hyperemesis gravidarum: current perspectives

    PubMed Central

    McCarthy, Fergus P; Lutomski, Jennifer E; Greene, Richard A

    2014-01-01

    Hyperemesis gravidarum is a complex condition with a multifactorial etiology characterized by severe intractable nausea and vomiting. Despite a high prevalence, studies exploring underlying etiology and treatments are limited. We performed a literature review, focusing on articles published over the last 10 years, to examine current perspectives and recent developments in hyperemesis gravidarum. PMID:25125986

  9. Marijuana: Current Concepts†

    PubMed Central

    Greydanus, Donald E.; Hawver, Elizabeth K.; Greydanus, Megan M.; Merrick, Joav

    2013-01-01

    Marijuana (cannabis) remains a controversial drug in the twenty-first century. This paper considers current research on use of Cannabis sativa and its constituents such as the cannabinoids. Topics reviewed include prevalence of cannabis (pot) use, other drugs consumed with pot, the endocannabinoid system, use of medicinal marijuana, medical adverse effects of cannabis, and psychiatric adverse effects of cannabis use. Treatment of cannabis withdrawal and dependence is difficult and remains mainly based on psychological therapy; current research on pharmacologic management of problems related to cannabis consumption is also considered. The potential role of specific cannabinoids for medical benefit will be revealed as the twenty-first century matures. However, potential dangerous adverse effects from smoking marijuana are well known and should be clearly taught to a public that is often confused by a media-driven, though false message and promise of benign pot consumption. PMID:24350211

  10. The NLM current catalog.

    PubMed

    Wiggins, E V

    1969-01-01

    When the National Library of Medicine acquired a computer to augment its publication program, the intent was to present in one medium an index to journal articles and a catalog of books and new serial titles. The computer programs designed for indexing were unsatisfactory for cataloging, however; so two publications were issued, the Index Medicus and the NLM Current Catalog. The Current Catalog features separate name and subject sections, added volumes, and technical reports. The Express Cataloging Service was one of the first attempts to increase the speed and coverage of the Catalog. Shared cataloging with the Library of Congress, the Countway Library at Harvard, and the Upstate Medical Library in Syracuse, New York, have also contributed to the efforts toward improving this library service. An additional shared cataloging program, this time with the National Medical Audiovisual Center, is expected to be implemented shortly. PMID:5782262

  11. Currents in Saturn's magnetosphere

    NASA Technical Reports Server (NTRS)

    Connerney, J. E. P.; Acuna, M. H.; Ness, N. F.

    1983-01-01

    A model of Saturn's magnetospheric magnetic field is obtained from the Voyager 1 and 2 observations. A representation consisting of the Z sub 3 zonal harmonic model of Saturn's planetary magnetic field together with an explicit model of Saturn's planetary magnetic field and a model of the equatorial ring current fits the observations well within r 20 R sub S, with the exception of data obtained during the Voyager 2 inbound pass.

  12. Neonatal resuscitation: Current issues

    PubMed Central

    Chadha, Indu A

    2010-01-01

    The following guidelines are intended for practitioners responsible for resuscitating neonates. They apply primarily to neonates undergoing transition from intrauterine to extrauterine life. The updated guidelines on Neonatal Resuscitation have assimilated the latest evidence in neonatal resuscitation. Important changes with regard to the old guidelines and recommendations for daily practice are provided. Current controversial issues concerning neonatal resuscitation are reviewed and argued in the context of the ILCOR 2005 consensus. PMID:21189881

  13. Current oscillations in nanopores

    NASA Astrophysics Data System (ADS)

    Hyland, Brittany

    We develop a simple phenomenological model to describe current oscillations in single, conically shaped nanopores. The model utilizes aspects of reaction rate theory, electrochemical oscillators, and nonlinear dynamical systems. Time series of experimental data were analyzed and compared to time series simulated using the model equations. There is good qualitative agreement between experiment and simulation, though the model needs to be improved in order to obtain better quantitative agreement.

  14. Current sheet model

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The model of a rectenna based on the current sheet equivalency of a large planar array is described. The model is mathematically characterized by expression for the fraction of the incident plane wave that is reflected from the sheet. The model is conceptually justified for normal incidence by comparing it to the waveguide model in which evanescent modes, present as beyond and cutoff, correspond to the near field components which become negligible at any significant distance from the antenna array.

  15. Fuel cell current collector

    DOEpatents

    Katz, Murray; Bonk, Stanley P.; Maricle, Donald L.; Abrams, Martin

    1991-01-01

    A fuel cell has a current collector plate (22) located between an electrode (20) and a separate plate (25). The collector plate has a plurality of arches (26, 28) deformed from a single flat plate in a checkerboard pattern. The arches are of sufficient height (30) to provide sufficient reactant flow area. Each arch is formed with sufficient stiffness to accept compressive load and sufficient resiliently to distribute the load and maintain electrical contact.

  16. Turbidity Current Head Mixing

    NASA Astrophysics Data System (ADS)

    Hernandez, David; Sanchez, Miguel Angel; Medina, Pablo

    2010-05-01

    A laboratory experimental set - up for studying the behaviour of sediment in presence of a turbulent field with zero mean flow is compared with the behaviour of turbidity currents [1] . Particular interest is shown on the initiation of sediment motion and in the sediment lift - off. The behaviour of the turbidity current in a flat ground is compared with the zero mean flow oscilating grid generated turbulence as when wave flow lifts off suspended sediments [2,3]. Some examples of the results obtained with this set-up relating the height of the head of the turbidity current to the equilibrium level of stirred lutoclines are shown. A turbulent velocity u' lower than that estimated by the Shield diagram is required to start sediment motion. The minimum u' required to start sediment lift - off, is a function of sediment size, cohesivity and resting time. The lutocline height depends on u', and the vorticity at the lutocline seems constant for a fixed sediment size [1,3]. Combining grid stirring and turbidty current head shapes analyzed by means of advanced image analysis, sediment vertical fluxes and settling speeds can be measured [4,5]. [1] D. Hernandez Turbulent structure of turbidity currents and sediment transport Ms Thesis ETSECCPB, UPC. Barcelona 2009. [2] A. Sánchez-Arcilla; A. Rodríguez; J.C. Santás; J.M. Redondo; V. Gracia; R. K'Osyan; S. Kuznetsov; C. Mösso. Delta'96 Surf-zone and nearshore measurements at the Ebro Delta. A: International Conference on Coastal Research through large Scale Experiments (Coastal Dynamics '97). University of Plymouth, 1997, p. 186-187. [3] P. Medina, M. A. Sánchez and J. M. Redondo. Grid stirred turbulence: applications to the initiation of sediment motion and lift-off studies Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere. 26, Issue 4, 2001, Pages 299-304 [4] M.O. Bezerra, M. Diez, C. Medeiros, A. Rodriguez, E. Bahia., A. Sanchez-Arcilla and J.M. Redondo. Study on the influence of waves on

  17. Hadron structure in {tau}{yields}KK{pi}{nu}{sub {tau}}decays

    SciTech Connect

    Gomez Dumm, D.; Roig, P.; Pich, A.; Portoles, J.

    2010-02-01

    We analyze the hadronization structure of both vector and axial-vector currents leading to {tau}{yields}KK{pi}{nu}{sub {tau}}decays. At leading order in the 1/N{sub C} expansion, and considering only the contribution of the lightest resonances, we work out, within the framework of the resonance chiral Lagrangian, the structure of the local vertices involved in those processes. The couplings in the resonance theory are constrained by imposing the asymptotic behavior of vector and axial-vector spectral functions ruled by QCD. In this way we predict the hadron spectra and conclude that, contrary to previous assertions, the vector contribution dominates by far over the axial-vector one in all KK{pi} charge channels.

  18. Current concepts in osteoarthritis

    PubMed Central

    de Rezende, Márcia Uchôa; de Campos, Gustavo Constantino; Pailo, Alexandre Felício

    2013-01-01

    Osteoarthritis (OA), the most common form of joint disease, affects mainly the hips, knees, hands and feet, leading to severe disability and loss of quality of life, particularly in the elderly population. Its importance grows every year with the aging of the population, with a large increase in the elderly population compared to younger patients. The progressive understanding of the pathophysiology of OA, the perception that the process is not purely mechanical and / or aging, and clarification of the inflammatory pathways involved led recently to the clinical application of various drugs and other measures. This update aims to expose the current concepts on the pathophysiology and treatment of OA. PMID:24453655

  19. Current collector for AMTEC

    NASA Technical Reports Server (NTRS)

    Williams, Roger M. (Inventor)

    1989-01-01

    An electrode having higher power output is formed of an open mesh current collector such as expanded nickel covering an electrode film applied to a tube of beta-alumina solid electrolyte (BASE). A plurality of cross-members such as spaced, parallel loops of molybdenum metal wire surround the BASE tube. The loops are electrically connected by a bus wire. As the AMTEC cell is heated, the grid of expanded nickel expands more than the BASE tube and the surrounding loop of wire and become diffusion welded to the electrode film and to the wire loops.

  20. Spin Currents in Silicon

    NASA Astrophysics Data System (ADS)

    Appelbaum, Ian

    2011-03-01

    I will discuss the results of our recent spin injection experiments using long-distance non-degenerate undoped (and n-type doped) Si devices. We have a unique capability to recover the details of electron transport on a sub-ns timescale through a ``Larmor clock'' transformation of spin precession data, despite using only quasistatic current measurements. I suggest that this is potentially a new tool for probing non-equilibrium phenomena in semiconductors, revealing both intrinsic and extrinsic materials properties through sensitivity to subtleties of the bandstructure and impurity spectrum. Supported by ONR and NSF.

  1. Waterborne cryptosporidiosis: current status.

    PubMed

    Smith, H V; Rose, J B

    1998-01-01

    In the past ten years Cryptosporidium oocysts have been shown to be common contaminants of water, causing at least 19 waterborne outbreaks of cryptosporidiosis which have affected more than 427 000 individuals. Recommended methods for oocyst isolation and enumeration are time-consuming and inefficient and experts state that the absence of Cryptosporidium oocysts in drinking water can never be guaranteed. In the UK alone, a National Research Programme costing pound3 million has been undertaken. Here, Huw Smith and Joan Rose review the current status of knowledge and identify approaches taken by UK and USA Government regulatory bodies in order to reduce the likelihood of waterborne transmission. PMID:17040684

  2. Low Current Magnet

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Because Goddard Space Flight Center needed a way to cool sensors aboard the AXAF, a low current superconducting magnet was developed under contract by Cryomagnetics, Inc. The magnet, now commercially available, reduced the rate of helium consumption, extending the lifetime of the AXAF's x-ray spectrometer. On Earth, it offers a way to reduce operating costs through smaller, less expensive power supplies and reduced use of coolant. The magnet has particular advantages for MRI systems, as it is safer and has lower maintenance requirements.

  3. Saturn's Other Ring Current

    NASA Astrophysics Data System (ADS)

    Crary, F. J.

    2014-04-01

    Saturn's main rings orbit the planet within an atmosphere and ionosphere of water, oxygen and hydrogen, produced by meteoritic impacts on and ultraviolet photodesorbtion of the ring particles [Johnson et al., 2006; Luhmann et al., 2006; Tseng et al., 2010]. The neutral atmosphere itself has only been tentatively detected through ultraviolet fluorescents of OH [Hall et al., 1996] while the ionosphere was observed in situ by the Cassini spacecraft shortly after orbital insertion [Coates et al.,2005; Tokar et al. 2005, Waite et al. 2005]. Although the plasma flow velocity of this ionosphere is not well-constrained, but the close association with the rings suggests that its speed would be couppled to the keplarian velocity of the rings themselves. As a result, the motion of the plasma through Saturn's magnetic field would produce an induced voltage, oriented away from the planet outside synchronous orbit and towards the planet inside synchronous orbit. Such a potential could result in currents flowing across the ring plane and closeing along magnetic field lines and through Saturn's ionosphere at latitudes between 36o and 48o. Cassini observations of whistler-mode plasma wave emissions [Xin et al.,2006] centered on synchronous orbit (1.76 Rs, mapping to 41o latitude) have been interpreted as a product of field-aligned electron beams associated with such a current. This presentation will investigate the magnitude of these currents and the resulting Joule heating of the ionosphere. An important constraint is that no auroral ultraviolet emissions have been observed at the relevant latitudes. In contrast, Joule heating could affect infrared emissions from H3+. Variations in H3+ emission associated with Saturn's rings have been reported by O'Donoghue et al., 2013, and interpreted as a result of ring "rain", i.e. precipitating water group species from the rings which alter ionosphereic chemistry and H3+ densities. As noted by O'Donoghue et al., this interpretation may be

  4. Optical Fibre Current Measurement

    NASA Astrophysics Data System (ADS)

    Rogers, A. J.

    1983-08-01

    Passive optical devices offer valuable technical and economic advantages for power-system current and voltage measurement. Such devices can also be used to measure a variety of other power-system parameters (e.g. temperature, pressure, strain, etc.). The main advantages of all such devices may be summarized as follows: (i) No powering is required at high voltage points. (ii) There is freedom from saturation effects. (iii) They have large measurement bandwith. (iv) The measurement sensitivity is high. (v) The costs are low and are not strongly dependent on system voltages. (vi) They are readily interfaced with interference-immune communications links.

  5. Aternating current photovoltaic building block

    DOEpatents

    Bower, Ward Issac; Thomas, Michael G.; Ruby, Douglas S.

    2004-06-15

    A modular apparatus for and method of alternating current photovoltaic power generation comprising via a photovoltaic module, generating power in the form of direct current; and converting direct current to alternating current and exporting power via one or more power conversion and transfer units attached to the module, each unit comprising a unitary housing extending a length or width of the module, which housing comprises: contact means for receiving direct current from the module; one or more direct current-to-alternating current inverters; an alternating current bus; and contact means for receiving alternating current from the one or more inverters.

  6. Misophonia: current perspectives

    PubMed Central

    Cavanna, Andrea E; Seri, Stefano

    2015-01-01

    Misophonia is characterized by a negative reaction to a sound with a specific pattern and meaning to a given individual. In this paper, we review the clinical features of this relatively common yet underinvestigated condition, with focus on co-occurring neurodevelopmental disorders. Currently available data on the putative pathophysiology of the condition can inform our understanding and guide the diagnostic process and treatment approach. Tinnitus retraining therapy and cognitive behavior therapy have been proposed as the most effective treatment strategies for reducing symptoms; however, current treatment algorithms should be validated in large population studies. At the present stage, competing paradigms see misophonia as a physiological state potentially inducible in any subject, an idiopathic condition (which can present with comorbid psychiatric disorders), or a symptomatic manifestation of an underlying psychiatric disorder. Agreement on the use of standardized diagnostic criteria would be an important step forward in terms of both clinical practice and scientific inquiry. Areas for future research include phenomenology, epidemiology, modulating factors, neurophysiological underpinnings, and treatment trials. PMID:26316758

  7. Ocular tuberculosis: current perspectives

    PubMed Central

    Shakarchi, Faiz I

    2015-01-01

    The World Health Organization currently estimates that nearly two billion people, or one-third of the world’s population, are infected by tuberculosis, and that roughly 10% of the infected people are symptomatic. Tuberculosis affects the lungs in 80% of patients, while in the remaining 20% the disease may affect other organs, including the eye. Uveitis can be seen concurrently with tuberculosis, but a direct association is difficult to prove. Ocular tuberculosis is usually not associated with clinical evidence of pulmonary tuberculosis, as up to 60% of extrapulmonary tuberculosis patients may not have pulmonary disease. The diagnosis of tuberculous uveitis is often problematic and in nearly all reported cases, the diagnosis was only presumptive. Tuberculous uveitis is a great mimicker of various uveitis entities and it can be considered in the differential diagnosis of any type of intraocular inflammation. It is still unknown if ocular manifestations result from a direct mycobacterium infection or hypersensitivity reaction and this is reflected on the management of tuberculous uveitis. Prevalence of tuberculosis as an etiology of uveitis may reach up to 10% in endemic areas. Tuberculous uveitis is a vision-threatening disease that inevitably leads to blindness if not properly diagnosed and treated. The aim of this review is to illustrate the various clinical features and management of presumed tuberculous uveitis. The current review focuses on the diagnostic criteria, significance of tuberculin skin test, and use of systemic corticosteroids in the management of tuberculous uveitis as recommended in recent publications. PMID:26648690

  8. [Malabsorption: current diagnosis trends].

    PubMed

    Valentini, G; Capristo, E; De Vitis, I; Gasbarrini, G

    2000-03-01

    The aim of this study was to review the problem of malabsorption, listing the main causes and the methods currently used to evaluate the gravity of the syndrome. The study was based primarily on data reported in the literature and on our personal experience at the Institute of Internal Medicine and Geriatrics at UCSC. Malabsorption is the term used to describe the defective passage through the intestinal mucosa of normal digestive products (this definition excludes the major chapter of maldigestion). Among the various methods currently used to study this problem, the authors list the most commonly used, highlighting two widely available instruments that are regarded as essential: anamnesis and objective examination. We have noticed that endless tests are often requested for a condition of malabsorption, which are not only expensive but also poorly tolerated by the patient, owing to the lack of a correct diagnostic approach based on a correct anamnesis and thorough objective examination. Lastly, we have put forward a number of guidelines based on personal experience to be followed when examining a patient with suspected malabsorption. PMID:16498348

  9. Current Climate Variability & Change

    NASA Astrophysics Data System (ADS)

    Diem, J.; Criswell, B.; Elliott, W. C.

    2013-12-01

    Current Climate Variability & Change is the ninth among a suite of ten interconnected, sequential labs that address all 39 climate-literacy concepts in the U.S. Global Change Research Program's Climate Literacy: The Essential Principles of Climate Sciences. The labs are as follows: Solar Radiation & Seasons, Stratospheric Ozone, The Troposphere, The Carbon Cycle, Global Surface Temperature, Glacial-Interglacial Cycles, Temperature Changes over the Past Millennium, Climates & Ecosystems, Current Climate Variability & Change, and Future Climate Change. All are inquiry-based, on-line products designed in a way that enables students to construct their own knowledge of a topic. Questions representative of various levels of Webb's depth of knowledge are embedded in each lab. In addition to the embedded questions, each lab has three or four essential questions related to the driving questions for the lab suite. These essential questions are presented as statements at the beginning of the material to represent the lab objectives, and then are asked at the end as questions to function as a summative assessment. For example, the Current Climate Variability & Change is built around these essential questions: (1) What has happened to the global temperature at the Earth's surface, in the middle troposphere, and in the lower stratosphere over the past several decades?; (2) What is the most likely cause of the changes in global temperature over the past several decades and what evidence is there that this is the cause?; and (3) What have been some of the clearly defined effects of the change in global temperature on the atmosphere and other spheres of the Earth system? An introductory Prezi allows the instructor to assess students' prior knowledge in relation to these questions, while also providing 'hooks' to pique their interest related to the topic. The lab begins by presenting examples of and key differences between climate variability (e.g., Mt. Pinatubo eruption) and

  10. Current Opinions on Tendinopathy

    PubMed Central

    Kaux, Jean-François; Forthomme, Bénédicte; Goff, Caroline Le; Crielaard, Jean-Michel; Croisier, Jean-Louis

    2011-01-01

    Tendinopathy is characterized by pain in the tendon and impaired performance sometimes associated with swelling of the tendon. Its diagnosis is usually clinical but ultrasonography and magnetic resonance imaging can refine the diagnosis. Tendinopathy is highly prevalent and is one of the most frequently self reported musculoskeletal diseases in physical workers and sports people. Nevertheless, it is very difficult to carry out general epidemiologic studies on tendinopathy because of the varying sports cultures and sports habits in different countries. The aetiology of tendinopathy seems to be multi-factorial, involving intrinsic and extrinsic factors. The role of inflammation is still debated but the absence of inflammatory cells does not mean that inflammatory mediators are not implicated. Different theories have been advanced to explain pain and chronicity mechanisms, but these mechanisms remain largely unknown. “Conventional ”treatments are generally employed empirically to fight pain and inflammation but they do not modify the histological structure of the tendon. However, these treatments are not completely satisfactory and the recurrence of symptoms is common. Currently, eccentric training remains the treatment of choice for tendinopathy, even though some studies are contradictory. Moreover, many interesting new treatments are now being developed to treat tendinopathy, but there is little evidence to support their use in clinical practice. Key points The word “tendinopathy ”is the correct term for the clinical diagnosis of pain accompanied by impaired performance, and sometimes swelling in the tendon. The aetiology of tendinopathy seems to be a multi-factorial process, involving promoting factors that are intrinsic or extrinsic, working either alone or in combination. US (with color Doppler) and MRI are usually prescribed when tendinopathy is unresponsive to treatment and entails lingering symptoms. Eccentric training is currently considered to be the

  11. Transungual permeation: current insights.

    PubMed

    Bhuptani, Ronak S; Deshpande, Ketaki M; Patravale, Vandana B

    2016-08-01

    Nail disorders are beyond cosmetic concern; besides discomfort in the performance of daily chores, they disturb patients psychologically and affect their quality of life. Fungal nail infection (onychomycosis) is the most prevalent nail-related disorder affecting a major population worldwide. Overcoming the impenetrable nail barrier is the toughest challenge for the development of efficacious topical ungual formulation. Sophisticated techniques such as iontophoresis and photodynamic therapy have been proven to improve transungual permeation. This article provides an updated and concise discussion regarding the conventional approach and upcoming novel approaches focused to alter the nail barrier. A comprehensive description regarding preformulation screening techniques for the identification of potential ungual enhancers is also described in this review while highlighting the current pitfalls for the development of ungual delivery. PMID:26419676

  12. Currently available antitussives.

    PubMed

    Dicpinigaitis, Peter V

    2009-04-01

    Cough is among the most common complaints for which patients seek medical attention. Acute cough, usually due to a viral upper respiratory tract infection, generates a huge expenditure on prescription and over-the-counter cough and cold preparations worldwide. Most of these agents, however, have not been shown to be more effective than placebo in adequately performed clinical trials. The goal of management in chronic cough is treatment of its underlying cause. However, certain situations will necessitate cough suppressant therapy for symptomatic relief. Unfortunately, currently available antitussives, such as the opioids, are not consistently effective, or achieve therapeutic effect at the expense of unpleasant or intolerable side effects. Safer and more effective cough suppressants are desperately needed. Potential novel antitussives will need to be evaluated in properly formulated clinical trials, measuring relevant subjective and objective end points in appropriate subject populations. PMID:18771744

  13. Cancer biomarkers - current perspectives.

    PubMed

    Bhatt, Anant Narayan; Mathur, Rohit; Farooque, Abdullah; Verma, Amit; Dwarakanath, B S

    2010-08-01

    In the recent years, knowledge about cancer biomarkers has increased tremendously providing great opportunities for improving the management of cancer patients by enhancing the efficiency of detection and efficacy of treatment. Recent technological advancement has enabled the examination of many potential biomarkers and renewed interest in developing new biomarkers. Biomarkers of cancer could include a broad range of biochemical entities, such as nucleic acids, proteins, sugars, lipids, and small metabolites, cytogenetic and cytokinetic parameters as well as whole tumour cells found in the body fluid. A comprehensive understanding of the relevance of each biomarker will be very important not only for diagnosing the disease reliably, but also help in the choice of multiple therapeutic alternatives currently available that is likely to benefit the patients. This review provides a brief account on various biomarkers for diagnosis, prognosis and therapeutic purposes, which include markers already in clinical practice as well as various upcoming biomarkers. PMID:20716813

  14. Introducing Current Technologies

    NASA Technical Reports Server (NTRS)

    Mitchell, Tiffany

    1995-01-01

    The objective of the study was a continuation of the 'technology push' activities that the Technology Transfer Team conducts at this time. It was my responsibility to research current technologies at Langley Research Center and find a commercial market for these technologies in the private industry. After locating a market for the technologies, a mailing package was put together which informed the companies of the benefits of NASA Langley's technologies. The mailing package included articles written about the technology, patent material, abstracts from technical papers, and one-pagers which were used at the Technology Opportunities Showcase (TOPS) exhibitions. The companies were encouraged to consult key team members for further information on the technologies.

  15. Synthetic ligaments. Current status.

    PubMed

    Funk, F J

    1987-06-01

    Many techniques for ligamentous reconstruction have been developed in recent years. In the United States, injuries of the knee have been increasingly treated with innovative methods of surgical reconstruction, most of which have used normal structures. There are obvious theoretic advantages in using synthetic materials that might simplify surgery, spare normal tissues, and possibly facilitate stronger repairs. To these ends, several synthetic substances have been used experimentally and clinically. This is a brief summary of eight of the materials that have been or are being investigated in the United States. Some are no longer in use, others are currently being used in clinical trials. As of this writing, only the Gortex ligament has received a general device release from the Food and Drug Administration (FDA). PMID:3034461

  16. Current LISA Spacecraft Design

    NASA Technical Reports Server (NTRS)

    Merkowitz, Stephen

    2008-01-01

    The Laser Interferometer Space Antenna (LISA) mission, a space based gravitational wave detector, uses laser metrology to measure distance fluctuations between proof masses aboard three spacecraft. LISA is unique from a mission design perspective in that three spacecraft and their associated operations form one distributed science instrument, unlike more conventional missions where an instrument is a component of an individual spacecraft. The design of the LiSA spacecraft is also tightly coupled to the design and requirements of the scientific payload; for this reason it is often referred to as a "sciencecraft." A detailed discussion will be presented that describes the current spacecraft design and mission architecture needed to meet the LISA science requirements.

  17. Achalasia: current treatment options.

    PubMed

    Familiari, Pietro; Greco, Santi; Volkanovska, Ance; Gigante, Giovanni; Cali, Anna; Boškoski, Ivo; Costamagna, Guido

    2015-01-01

    Achalasia is a rare esophageal motility disorder, characterized by impaired swallow-induced, lower esophageal sphincter (LES) relaxation and defective esophageal peristalsis. Unfortunately, there are no etiological therapies for achalasia. Patients present with dysphagia, chest pain and regurgitation of undigested food, often leading to weight loss. The currently available treatments have the common aim of relieving symptoms by decreasing the pressure of the LES. This can be achieved with some medications, by inhibiting the cholinergic innervation (botulinum toxin), by stretching (endoscopic dilation) or cutting (surgery) the LES. Recently, other therapeutic options, including per-oral endoscopic myotomy have been developed and are gaining international consensus. The authors report on the benefits and weaknesses of the different therapies and provide an updated approach to the management of achalasia. PMID:26186641

  18. Current Management of NAFLD

    PubMed Central

    MUNTEANU, MIHAI ALEXANDRU; NAGY, GEORGIANA ANCA; MIRCEA, PETRU ADRIAN

    2016-01-01

    Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in Western countries. It affects about 1 billion individuals worldwide. While people with simple steatosis have no higher risk of death than the general population, people with non-alcoholic steatohepatitis are at increased risk of death compared to general population. Current management for NAFLD includes diet and lifestyle changes, management of underlying metabolic risk factors and pharmacological therapies. The objective of therapy is to prevent the complications. The problem with dietary and lifestyle interventions is that they are hard to implement. Compliance is the key. Until now, there is still no approved drug for the treatment of NAFLD. Insulin resistance is the main target of pharmacological therapy, but the question that we ask ourselves as physicians is who should receive medical treatment among NAFLD patients and for how long. PMID:27004021

  19. Brain abscess: Current management

    PubMed Central

    Alvis Miranda, Hernando; Castellar-Leones, Sandra Milena; Elzain, Mohammed Awad; Moscote-Salazar, Luis Rafael

    2013-01-01

    Brain abscess (BA) is defined as a focal infection within the brain parenchyma, which starts as a localized area of cerebritis, which is subsequently converted into a collection of pus within a well-vascularized capsule. BA must be differentiated from parameningeal infections, including epidural abscess and subdural empyema. The BA is a challenge for the neurosurgeon because it is needed good clinical, pharmacological, and surgical skills for providing good clinical outcomes and prognosis to BA patients. Considered an infrequent brain infection, BA could be a devastator entity that easily left the patient into dead. The aim of this work is to review the current concepts regarding epidemiology, pathophysiology, etiology, clinical presentation, diagnosis, and management of BA. PMID:24174804

  20. Football injuries: current concepts.

    PubMed

    Olson, David E; Sikka, Robby Singh; Hamilton, Abigail; Krohn, Austin

    2011-01-01

    Football is one of the most popular sports in the United States and is the leading cause of sports-related injury. A large focus in recent years has been on concussions, sudden cardiac death, and heat illness, all thought to be largely preventable health issues in the young athlete. Injury prevention through better understanding of injury mechanisms, education, proper equipment, and practice techniques and preseason screening may aid in reducing the number of injuries. Proper management of on-field injuries and health emergencies can reduce the morbidity associated with these injuries and may lead to faster return to play and reduced risk of future injury. This article reviews current concepts surrounding frequently seen football-related injuries. PMID:23531977

  1. Brain abscess: Current management.

    PubMed

    Alvis Miranda, Hernando; Castellar-Leones, Sandra Milena; Elzain, Mohammed Awad; Moscote-Salazar, Luis Rafael

    2013-08-01

    Brain abscess (BA) is defined as a focal infection within the brain parenchyma, which starts as a localized area of cerebritis, which is subsequently converted into a collection of pus within a well-vascularized capsule. BA must be differentiated from parameningeal infections, including epidural abscess and subdural empyema. The BA is a challenge for the neurosurgeon because it is needed good clinical, pharmacological, and surgical skills for providing good clinical outcomes and prognosis to BA patients. Considered an infrequent brain infection, BA could be a devastator entity that easily left the patient into dead. The aim of this work is to review the current concepts regarding epidemiology, pathophysiology, etiology, clinical presentation, diagnosis, and management of BA. PMID:24174804

  2. Bone strength: current concepts.

    PubMed

    Turner, Charles H

    2006-04-01

    Bones serve several mechanical functions, including acoustic amplification in the middle ear, shielding vital organs from trauma, and serving as levers for muscles to contract against. Bone is a multiphase material made up of a tough collagenous matrix intermingled with rigid mineral crystals. The mineral gives bone its stiffness. Without sufficient mineralization, bones will plastically deform under load. Collagen provides toughness to bone making it less brittle so that it better resists fracture. Bone adapts to mechanical stresses largely by changing its size and shape, which are major determinants of its resistance to fracture. Tissue is added in regions of high mechanical stress providing an efficient means for improving bone strength. Experiments have shown that small additions of bone mineral density (BMD) (5-8%) caused by mechanical loading can improve bone strength by over 60% and extend bone fatigue life by 100-fold. Consequently, it is clear that bone tissue possesses a mechanosensing apparatus that directs osteogenesis to where it is most needed for improving bone strength. The biological processes involved in bone mechanotransduction are poorly understood and further investigation of the molecular mechanisms involved might uncover drug targets for osteoporosis. Several pathways are emerging from current research, including membrane ion channels, ATP signaling, second messengers, such as prostaglandins and nitric oxide, insulin-like growth factors, and Wnt signaling. PMID:16831941

  3. Current Intelligence Bulletins: summaries

    SciTech Connect

    Not Available

    1986-07-24

    Summaries are provided for the 47 Current Intelligence Bulletins issued to date by NIOSH; any revisions in NIOSH policy made after a bulletin was issued are included. Subjects of the bulletins include the following: chloroprene; trichloroethylene; ethylene-dibromide; chrome pigment; asbestos exposure; hexamethylphosphoric-triamide; polychlorinated biphenyls; 4,4'-diaminodipheylmethane; chloroform; radon daughters; dimethylcarbamoyl-chloride; diethylcarbamoyl-chloride; explosive azide hazard; inorganic arsenic; nitrosamines; metabolic precursors of beta-naphtylamine; 2-nitropropane; acryonitrile; 2,4-diaminoanisole; tetrachloroethylene; trimellitic-anhydride; ethylene-thiourea; ethylene-dibromide and disulfiram, toxic interaction; direct blue 6, direct black 38, direct brown 95, benzidine derived dyes; ethylene-dichloride; NIAX catalyst ESN; chloroethanes, review of toxicity; vinyl halides, carcinogenicity; glycidyl ethers; epichlorohydrin; smoking and the occupational environment; arsine poisoning in the workplace; radiofrequency sealers and heaters; formaldehyde; ethylene-oxide; silica flour; ethylene-dibromide; vibration syndrome; glycol ethers; 2,3,7,8-tetrachlorodibenzo-p-dioxin; 1,3-butadiene; cadmium; monohalomethanes; dinitrotoluenes; polychlorinated biphenyls in electrical equipment fires or failures; methylene-chloride; and 4,4' methylenedianiline.

  4. Brief Psychotherapy: Current Status

    PubMed Central

    Castelnuovo-Tedesco, Pietro

    1967-01-01

    In the past decade, stimulated by public concern with issues of mental health, there has been a new spurt of interest in techniques of brief treatment with circumscribed goals. These are applicable to groups as well as to the single patient. There are still differences of opinion about the effectiveness of brief psychotherapy, particularly the lastingness and depth of the results obtained, yet it is often highly beneficial, especially to previously well-functioning individuals who are involved in a situational crisis. Although probably the best results of brief psychotherapy are with disturbances of moderate severity and recent onset, in practice, it is often tried with a wide spectrum of patients. Brief psychotherapy aims at relief of the patient's major current conflicts rather than at change of his personality structure, which generally requires long-term treatment. Brief psychotherapy is of special relevance for the general physician because the patients whom he sees in large numbers are precisely those best suited for this form of treatment. PMID:6075465

  5. NONDESTRUCTIVE EDDY CURRENT TESTING

    DOEpatents

    Renken, C.J. Jr.

    1961-05-23

    An eddy current testing device is described for measuring metal continuity independent of probe-to-sample spacing. An inductance would test probe is made a leg of a variable impedance bridge and the bridge is balanced with the probe away from the sample. An a-c signal is applied across the input terminals of the bridge circuit. As the probe is brought into proximity with the metal sample, the resulting impedance change in the probe gives an output signal from the bridge whose phase angle is proportional to the sample continuity and amplitude is proportional to the probe-tosample spacing. The output signal from the bridge is applied to a compensating network where, responsive to amplitude changes from the bridge output signal, a constant phased voltage output is maintained when the sample is continuous regardless of probe-to-sample spacing. A phase meter calibrated to read changes in resistivity of the metal sample measures the phase shift between the output of the compensating network and the original a-c signal applied to the bridge.

  6. [Current contact allergens].

    PubMed

    Geier, J; Uter, W; Lessmann, H; Schnuch, A

    2011-10-01

    Ever-changing exposure to contact allergens, partly due to statutory directives (e.g. nickel, chromate, methyldibromo glutaronitrile) or recommendations from industrial associations (e.g. hydroxyisohexyl 3-cyclohexene carboxaldehyde), requires on-going epidemiologic surveillance of contact allergy. In this paper, the current state with special focus in fragrances and preservatives is described on the basis of data of the Information Network of Departments of Dermatology (IVDK) of the year 2010. In 2010, 12,574 patients were patch tested in the dermatology departments belonging to the IVDK. Nickel is still the most frequent contact allergen. However the continuously improved EU nickel directive already has some beneficial effect; sensitization frequency in young women is dropping. In Germany, chromate-reduced cement has been in use now for several years, leading to a decline in chromate sensitization in brick-layers. Two fragrance mixes are part of the German baseline series; they are still relevant. The most important fragrances in these mixes still are oak moss absolute and hydroxyisohexyl 3-cyclohexene carboxaldehyde. However, in relation to these leading allergens, sensitization frequency to other fragrances contained in the mixes seems to be increasing. Among the preservatives, MCI/MI has not lost its importance as contact allergen, in contrast to MDBGN. Sources of MCI/MI sensitization obviously are increasingly found in occupational context. Methylisothiazolinone is a significant allergen in occupational settings, and less frequently in body care products. PMID:21901563

  7. Diabetic glomerulosclerosis: current status.

    PubMed Central

    Kalant, N.

    1978-01-01

    Current information on the nature, pathogenesis and treatment of diabetic glomerulosclerosis is reviewed. The fundamental lesion is one of the glomerular basement membrane, a complex layer of collage-like and other peptides; thickening of this membrane, seen microscopically, is due to the presence of an increased amount of membrane material of normal composition. There is little reliable evidence relating the frequency of glomerulosclerosis to the quality of control of the diabetic state, but indirect evidence from patients with secondary diabetes and from a variety of studies in animals indicates strongly that the glomerular lesion is a consequence of the abnormal metabolic state and can be prevented by adequate treatment of the diabetes. A concept of the pathogenesis of the glomerular lesions and renal failure is presented, but there remain large gaps in knowledge of the mechanisms involved. Treatment of chronic renal failure by maintenance renal dialysis and renal transplantation is not as successful in persons with diabetes as in those without this condition; however, the results appear to be improving, and transplantation particularly holds much promise. PMID:354765

  8. Integrated Current Limiter

    NASA Astrophysics Data System (ADS)

    Pappalardo, S.; Alfonso, M. M.; Mirabella, I. B.

    2011-10-01

    The LCL has been extensively used in ESA scientific satellites and since a few years ago is being also the baseline device for earth observation satellites such as CRYOSAT 1 and 2, SENTINAL 1, 2 and 3, EARTWATCH, etc. It seems that the use of this LCL is also being considered as an alternative to fuse approach for commercial telecommunication satellites. Scope of this document is to provide a technical description of the Integrated Current Limiter device (shortly ICL later on) developed inside the domain of ESTECContract22049-09-NL-A Twith STMicroelectronics s.r.l. (ref. Invitation to Tender AO/1-5784/08/NL/A T). The design of the ICL device takes into account both ESA and power electronics designer's experience. This experience is more than 25 years long in Europe. The ICL design has been leaded in order to be fully compliant with the applicable specification issued by ESA and the major European power electronics manufacturers that have participated in its edition.

  9. Circulating current battery heater

    DOEpatents

    Ashtiani, Cyrus N.; Stuart, Thomas A.

    2001-01-01

    A circuit for heating energy storage devices such as batteries is provided. The circuit includes a pair of switches connected in a half-bridge configuration. Unidirectional current conduction devices are connected in parallel with each switch. A series resonant element for storing energy is connected from the energy storage device to the pair of switches. An energy storage device for intermediate storage of energy is connected in a loop with the series resonant element and one of the switches. The energy storage device which is being heated is connected in a loop with the series resonant element and the other switch. Energy from the heated energy storage device is transferred to the switched network and then recirculated back to the battery. The flow of energy through the battery causes internal power dissipation due to electrical to chemical conversion inefficiencies. The dissipated power causes the internal temperature of the battery to increase. Higher internal temperatures expand the cold temperature operating range and energy capacity utilization of the battery. As disclosed, either fixed frequency or variable frequency modulation schemes may be used to control the network.

  10. [Current management of epilepsy].

    PubMed

    Mizobuchi, Masahiro

    2013-09-01

    Epilepsy is one of the most common neurological disorders. Global neurological knowledge is essential for differential diagnosis of epileptic syndromes due to the diversity of ictal semiology, causes and syndromes. Neurologists play an important role in planning the medical care for patients with epilepsy, as medication is the most fundamental therapeutic strategy. Some patients with early-onset epilepsy require joint care by pediatric neurologists, those with intractable epilepsy by neurosurgeons, and those with psychological comorbidity by psychiatrists, and neurologists should play a coordinating role. While there is a great need for neurologists to participate in epilepsy care, neurologists in Japan currently do not participate substantially in the epilepsy management system. It is necessary to train more neurologists who can provide epilepsy care and conduct basic and clinical research on epilepsy by providing continuous education on epilepsy for general neurologists as well as pre- and post-graduate medical students. Most of the patients who require long-term treatment experience many medical problems and social handicaps, such as adverse effects of medication, social stigma, educational disadvantages and difficulties in obtaining driver's license. To improve the quality of life of patients with epilepsy, it is desirable to build broad medical-social networks participated by patients, doctors, neurological nurses, psychologists, social workers, school teachers, managers of employment support facilities and care givers. PMID:24018740

  11. Theme: Staying Current--Horticulture.

    ERIC Educational Resources Information Center

    Shry, Carroll L., Jr.; And Others

    1986-01-01

    This theme issue on staying current in horticulture includes articles on sex equity in horticulture, Future Farmers of America, career opportunities in horticulture, staying current with your school district's needs, staying current in horticulture instruction, staying current with landscape trade associations, emphasizing the basics in vocational…

  12. Muscle dysmorphia: current insights.

    PubMed

    Tod, David; Edwards, Christian; Cranswick, Ieuan

    2016-01-01

    Since 1997, there has been increasing research focusing on muscle dysmorphia, a condition underpinned by people's beliefs that they have insufficient muscularity, in both the Western and non-Western medical and scientific communities. Much of this empirical interest has surveyed nonclinical samples, and there is limited understanding of people with the condition beyond knowledge about their characteristics. Much of the existing knowledge about people with the condition is unsurprising and inherent in the definition of the disorder, such as dissatisfaction with muscularity and adherence to muscle-building activities. Only recently have investigators started to explore questions beyond these limited tautological findings that may give rise to substantial knowledge advances, such as the examination of masculine and feminine norms. There is limited understanding of additional topics such as etiology, prevalence, nosology, prognosis, and treatment. Further, the evidence is largely based on a small number of unstandardized case reports and descriptive studies (involving small samples), which are largely confined to Western (North American, British, and Australian) males. Although much research has been undertaken since the term "muscle dysmorphia" entered the psychiatric lexicon in 1997, there remains tremendous scope for knowledge advancement. A primary task in the short term is for investigators to examine the extent to which the condition exists among well-defined populations to help determine the justification for research funding relative to other public health issues. A greater variety of research questions and designs may contribute to a broader and more robust knowledge base than currently exists. Future work will help clinicians assist a group of people whose quality of life and health are placed at risk by their muscular preoccupation. PMID:27536165

  13. Muscle dysmorphia: current insights

    PubMed Central

    Tod, David; Edwards, Christian; Cranswick, Ieuan

    2016-01-01

    Since 1997, there has been increasing research focusing on muscle dysmorphia, a condition underpinned by people’s beliefs that they have insufficient muscularity, in both the Western and non-Western medical and scientific communities. Much of this empirical interest has surveyed nonclinical samples, and there is limited understanding of people with the condition beyond knowledge about their characteristics. Much of the existing knowledge about people with the condition is unsurprising and inherent in the definition of the disorder, such as dissatisfaction with muscularity and adherence to muscle-building activities. Only recently have investigators started to explore questions beyond these limited tautological findings that may give rise to substantial knowledge advances, such as the examination of masculine and feminine norms. There is limited understanding of additional topics such as etiology, prevalence, nosology, prognosis, and treatment. Further, the evidence is largely based on a small number of unstandardized case reports and descriptive studies (involving small samples), which are largely confined to Western (North American, British, and Australian) males. Although much research has been undertaken since the term “muscle dysmorphia” entered the psychiatric lexicon in 1997, there remains tremendous scope for knowledge advancement. A primary task in the short term is for investigators to examine the extent to which the condition exists among well-defined populations to help determine the justification for research funding relative to other public health issues. A greater variety of research questions and designs may contribute to a broader and more robust knowledge base than currently exists. Future work will help clinicians assist a group of people whose quality of life and health are placed at risk by their muscular preoccupation. PMID:27536165

  14. Lead toxicity: Current concerns

    SciTech Connect

    Goyer, R.A. )

    1993-04-01

    Over the 20-year period since the first issue of Environmental Health Perspectives was published, there has been considerable progress in the understanding of the potential toxicity of exposure to lead. Many of these advances have been reviewed in published symposia, conferences, and review papers in EHP. This brief review identifies major advances as well as a number of current concerns that present opportunities for prevention and intervention strategies. The major scientific advance has been the demonstration that blood lead (PbB) levels of 10-15 micrograms/dL in newborn and very young infants result in cognitive and behavioral deficits. Further support for this observation is being obtained by prospective or longitudinal studies presently in progress. The mechanism(s) for the central nervous system effects of lead is unclear but involve lead interactions within calcium-mediated intracellular messenger systems and neurotransmission. Effects of low-level lead exposure on blood pressure, particularly in adult men, may be related to the effect of lead on calcium-mediated control of vascular smooth muscle contraction and on the renin-angiotensin system. Reproductive effects of lead have long been suspected, but low-level effects have not been well studied. Whether lead is a carcinogen or its association with renal adenocarcinoma is a consequence of cystic nephropathy is uncertain. Major risk factors for lead toxicity in children in the United States include nutrition, particularly deficiencies of essential metals, calcium, iron, and zinc, and housing and socioeconomic status. A goal for the year 2000 is to reduce prevalence of blood lead levels exceeding 15 micrograms/dL. 97 refs.

  15. High temperature current mirror amplifier

    DOEpatents

    Patterson, III, Raymond B.

    1984-05-22

    A high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is provided with a biasing means and current means on the input leg.

  16. Oscillatory nonhmic current drive for maintaining a plasma current

    DOEpatents

    Fisch, Nathaniel J.

    1986-01-01

    Apparatus and method of the invention maintain a plasma current with an oscillatory nonohmic current drive. Each cycle of operation has a generation period in which current driving energy is applied to the plasma, and a relaxation period in which current driving energy is removed. Plasma parameters, such as plasma temperature or plasma average ionic charge state, are modified during the generation period so as to oscillate plasma resistivity in synchronism with the application of current driving energy. The invention improves overall current drive efficiencies.

  17. Oscillatory nonohomic current drive for maintaining a plasma current

    DOEpatents

    Fisch, N.J.

    1984-01-01

    Apparatus and methods are described for maintaining a plasma current with an oscillatory nonohmic current drive. Each cycle of operation has a generation period in which current driving energy is applied to the plasma, and a relaxation period in which current driving energy is removed. Plasma parameters, such as plasma temperature or plasma average ionic charge state, are modified during the generation period so as to oscillate plasma resistivity in synchronism with the application of current driving energy. The invention improves overall current drive efficiencies.

  18. Magnesium Diboride Current Leads

    NASA Technical Reports Server (NTRS)

    Panek, John

    2010-01-01

    A recently discovered superconductor, magnesium diboride (MgB2), can be used to fabricate conducting leads used in cryogenic applications. Dis covered to be superconducting in 2001, MgB2 has the advantage of remaining superconducting at higher temperatures than the previously used material, NbTi. The purpose of these leads is to provide 2 A of electricity to motors located in a 1.3 K environment. The providing environment is a relatively warm 17 K. Requirements for these leads are to survive temperature fluctuations in the 5 K and 11 K heat sinks, and not conduct excessive heat into the 1.3 K environment. Test data showed that each lead in the assembly could conduct 5 A at 4 K, which, when scaled to 17 K, still provided more than the required 2 A. The lead assembly consists of 12 steelclad MgB2 wires, a tensioned Kevlar support, a thermal heat sink interface at 4 K, and base plates. The wires are soldered to heavy copper leads at the 17 K end, and to thin copper-clad NbTi leads at the 1.3 K end. The leads were designed, fabricated, and tested at the Forschungszentrum Karlsruhe - Institut foer Technische Physik before inclusion in Goddard's XRS (X-Ray Spectrometer) instrument onboard the Astro-E2 spacecraft. A key factor is that MgB2 remains superconducting up to 30 K, which means that it does not introduce joule heating as a resistive wire would. Because the required temperature ranges are 1.3-17 K, this provides a large margin of safety. Previous designs lost superconductivity at around 8 K. The disadvantage to MgB2 is that it is a brittle ceramic, and making thin wires from it is challenging. The solution was to encase the leads in thin steel tubes for strength. Previous designs were so brittle as to risk instrument survival. MgB2 leads can be used in any cryogenic application where small currents need to be conducted at below 30 K. Because previous designs would superconduct only at up to 8 K, this new design would be ideal for the 8-30 K range.

  19. 60. VIEW OF THE CURRENT TRANSFORMER VAULT. THIS CURRENT TRANSFORMER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    60. VIEW OF THE CURRENT TRANSFORMER VAULT. THIS CURRENT TRANSFORMER WAS USED TO SENSE HIGH CURRENT BEING GENERATED ON GENERATOR NUMBER 3 AND REDUCE IT TO A LOWER, EXACT ANALOG VALUE THAT COULD BE SAFELY HANDLED AND MONITORED WITH THE CONTROL CIRCUITRY. THE CURRENT TRANSFORMER IS LOCATED IN THE CENTER OF THE PHOTOGRAPH. THE CONNECTING BUS ABOVE THE TRANSFORMER WAS REMOVED FOR SALVAGE. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  20. Conformal symmetry limit of QED and QCD and identities between perturbative contributions to deep-inelastic scattering sum rules

    NASA Astrophysics Data System (ADS)

    Kataev, A. L.

    2014-02-01

    Conformal symmetry-based relations between concrete perturbative QED and QCD approximations for the Bjorken , the Ellis-Jaffe sum rules of polarized lepton- nucleon deep-inelastic scattering (DIS), the Gross-Llewellyn Smith sum rules of neutrino-nucleon DIS, and for the Adler functions of axial-vector and vector channels are derived. They result from the application of the operator product expansion to three triangle Green functions, constructed from the non-singlet axial-vector, and two vector currents, the singlet axial-vector and two non-singlet vector currents and the non-singlet axial-vector, vector and singlet vector currents in the limit, when the conformal symmetry of the gauge models with fermions is considered unbroken. We specify the perturbative conditions for this symmetry to be valid in the case of the U(1) and SU( N c) models. The all-order perturbative identity following from the conformal invariant limit between the concrete contributions to the Bjorken, the Ellis-Jaffe and the Gross-Llewellyn Smith sum rules is proved. The analytical and numerical O( α 4) and conformal symmetry based approximations for these sum rules and for the Adler function of the non-singlet vector currents are summarized. Possible theoretical applications of the results presented are discussed.

  1. On transport-driven currents

    SciTech Connect

    Ma, S.; Dawson, J.M. )

    1994-08-01

    An empirical electron viscosity is incorporated into Ohm's law to examine the effect of current diffusion on bootstrap currents. It is shown that for sufficiently large viscosity, no seed current is needed for steady state operation of tokamaks. This is expressed by the scaling law [Gamma][ital R][sup 2][sub [ital m

  2. Study of eddy current probes

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Wang, Morgan

    1992-01-01

    The recognition of materials properties still presents a number of problems for nondestructive testing in aerospace systems. This project attempts to utilize current capabilities in eddy current instrumentation, artificial intelligence, and robotics in order to provide insight into defining geometrical aspects of flaws in composite materials which are capable of being evaluated using eddy current inspection techniques.

  3. High temperature current mirror amplifier

    DOEpatents

    Patterson, R.B. III.

    1984-05-22

    Disclosed is a high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is provided with a biasing means and current means on the input leg. 2 figs.

  4. Magnetospheric electric fields and currents

    NASA Technical Reports Server (NTRS)

    Mauk, B. H.; Zanetti, L. J.

    1987-01-01

    The progress made in the years 1983-1986 in understanding the character and operation of magnetospheric electric fields and electric currents is discussed, with emphasis placed on the connection with the interior regions. Special attention is given to determinations of global electric-field configurations, measurements of the response of magnetospheric particle populations to the electric-field configurations, and observations of the magnetospheric currents at high altitude and during northward IMF. Global simulations of current distributions are discussed, and the sources of global electric fields and currents are examined. The topics discussed in the area of impulsive and small-scale phenomena include substorm current systems, impulsive electric fields and associated currents, and field-aligned electrodynamics. A key finding of these studies is that the electric fields and currents are interrelated and cannot be viewed as separate entities.

  5. Current-driven atomic waterwheels

    NASA Astrophysics Data System (ADS)

    Dundas, Daniel; McEniry, Eunan J.; Todorov, Tchavdar N.

    2009-02-01

    A current induces forces on atoms inside the conductor that carries it. It is now possible to compute these forces from scratch, and to perform dynamical simulations of the atomic motion under current. One reason for this interest is that current can be a destructive force-it can cause atoms to migrate, resulting in damage and in the eventual failure of the conductor. But one can also ask, can current be made to do useful work on atoms? In particular, can an atomic-scale motor be driven by electrical current, as it can be by other mechanisms? For this to be possible, the current-induced forces on a suitable rotor must be non-conservative, so that net work can be done per revolution. Here we show that current-induced forces in atomic wires are not conservative and that they can be used, in principle, to drive an atomic-scale waterwheel.

  6. Current-driven atomic waterwheels.

    PubMed

    Dundas, Daniel; McEniry, Eunan J; Todorov, Tchavdar N

    2009-02-01

    A current induces forces on atoms inside the conductor that carries it. It is now possible to compute these forces from scratch, and to perform dynamical simulations of the atomic motion under current. One reason for this interest is that current can be a destructive force--it can cause atoms to migrate, resulting in damage and in the eventual failure of the conductor. But one can also ask, can current be made to do useful work on atoms? In particular, can an atomic-scale motor be driven by electrical current, as it can be by other mechanisms? For this to be possible, the current-induced forces on a suitable rotor must be non-conservative, so that net work can be done per revolution. Here we show that current-induced forces in atomic wires are not conservative and that they can be used, in principle, to drive an atomic-scale waterwheel. PMID:19197311

  7. Fault current limiter and alternating current circuit breaker

    DOEpatents

    Boenig, H.J.

    1998-03-10

    A solid-state circuit breaker and current limiter are disclosed for a load served by an alternating current source having a source impedance, the solid-state circuit breaker and current limiter comprising a thyristor bridge interposed between the alternating current source and the load, the thyristor bridge having four thyristor legs and four nodes, with a first node connected to the alternating current source, and a second node connected to the load. A coil is connected from a third node to a fourth node, the coil having an impedance of a value calculated to limit the current flowing therethrough to a predetermined value. Control means are connected to the thyristor legs for limiting the alternating current flow to the load under fault conditions to a predetermined level, and for gating the thyristor bridge under fault conditions to quickly reduce alternating current flowing therethrough to zero and thereafter to maintain the thyristor bridge in an electrically open condition preventing the alternating current from flowing therethrough for a predetermined period of time. 9 figs.

  8. Fault current limiter and alternating current circuit breaker

    DOEpatents

    Boenig, Heinrich J.

    1998-01-01

    A solid-state circuit breaker and current limiter for a load served by an alternating current source having a source impedance, the solid-state circuit breaker and current limiter comprising a thyristor bridge interposed between the alternating current source and the load, the thyristor bridge having four thyristor legs and four nodes, with a first node connected to the alternating current source, and a second node connected to the load. A coil is connected from a third node to a fourth node, the coil having an impedance of a value calculated to limit the current flowing therethrough to a predetermined value. Control means are connected to the thyristor legs for limiting the alternating current flow to the load under fault conditions to a predetermined level, and for gating the thyristor bridge under fault conditions to quickly reduce alternating current flowing therethrough to zero and thereafter to maintain the thyristor bridge in an electrically open condition preventing the alternating current from flowing therethrough for a predetermined period of time.

  9. TOKAMAK EQUILIBRIA WITH CENTRAL CURRENT HOLES AND NEGATIVE CURRENT DRIVE

    SciTech Connect

    CHU, M.S.; PARKS, P.B.

    2002-06-01

    OAK B202 TOKAMAK EQUILIBRIA WITH CENTRAL CURRENT HOLES AND NEGATIVE CURRENT DRIVE. Several tokamak experiments have reported the development of a central region with vanishing currents (the current hole). Straightforward application of results from the work of Greene, Johnson and Weimer [Phys. Fluids, 3, 67 (1971)] on tokamak equilibrium to these plasmas leads to apparent singularities in several physical quantities including the Shafranov shift and casts doubts on the existence of this type of equilibria. In this paper, the above quoted equilibrium theory is re-examined and extended to include equilibria with a current hole. It is shown that singularities can be circumvented and that equilibria with a central current hole do satisfy the magnetohydrodynamic equilibrium condition with regular behavior for all the physical quantities and do not lead to infinitely large Shafranov shifts. Isolated equilibria with negative current in the central region could exist. But equilibria with negative currents in general do not have neighboring equilibria and thus cannot have experimental realization, i.e. no negative currents can be driven in the central region.

  10. ITER equilibrium with bootstrap currents, lower hybrid current drive and fast wave current drive

    SciTech Connect

    Ehst, D.A.

    1989-03-01

    A current drive system is proposed for the technology phase of ITER which relies on rf power and bootstrap currents. The rf/bootstrap system permits operation at high safety factor, and we consider the axial value to be q/sub a/ approx. = 1.9, which minimizes the need for seed current near the magnetic axis. Lower hybrid power (/approximately/30 MW) provides current density near the surface, ICRF (/approximately/65 MHz, /approximately/30 MW) fast waves generate current near the axis, and high frequency fast waves (/approximately/250 MHz, /approximately/74 MW) supply the remaining current density. The system is not yet optimized but appears to offer great flexibility (ion heating for ignition, current rampup, etc.) with relatively inexpensive and well developed technology. 29 refs., 16 figs., 1 tab.

  11. Ionization tube simmer current circuit

    DOEpatents

    Steinkraus, Jr., Robert F.

    1994-01-01

    A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current.

  12. Ionization tube simmer current circuit

    DOEpatents

    Steinkraus, R.F. Jr.

    1994-12-13

    A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current. 6 figures.

  13. Inductance due to spin current

    SciTech Connect

    Chen, Wei

    2014-03-21

    The inductance of spintronic devices that transport charge neutral spin currents is discussed. It is known that in a media that contains charge neutral spins, a time-varying electric field induces a spin current. We show that since the spin current itself produces an electric field, this implies existence of inductance and electromotive force when the spin current changes with time. The relations between the electromotive force and the corresponding flux, which is a vector calculated by the cross product of electric field and the trajectory of the device, are clarified. The relativistic origin generally renders an extremely small inductance, which indicates the advantage of spin current in building low inductance devices. The same argument also explains the inductance due to electric dipole current and applies to physical dipoles consist of polarized bound charges.

  14. DEEP WATER ISOTOPIC CURRENT ANALYZER

    DOEpatents

    Johnston, W.H.

    1964-04-21

    A deepwater isotopic current analyzer, which employs radioactive isotopes for measurement of ocean currents at various levels beneath the sea, is described. The apparatus, which can determine the direction and velocity of liquid currents, comprises a shaft having a plurality of radiation detectors extending equidistant radially therefrom, means for releasing radioactive isotopes from the shaft, and means for determining the time required for the isotope to reach a particular detector. (AEC)

  15. Current Collection from Space Plasmas

    NASA Technical Reports Server (NTRS)

    Singh, Nagendra (Editor); Wright, K. H., Jr. (Editor); Stone, Nobie H. (Editor)

    1990-01-01

    The First Workshop on Current Collection from Space Plasmas was held at the Tom Bevil Center on the campus of The University of Alabama in Huntsville on April 24 to 25, 1989. The intent of the workshop was to assemble experts on various topics related to the problem of current collection for deliberations that would elucidate the present understanding of the overall current collection problem. Papers presented at the workshop are presented.

  16. The current-voltage relationship in auroral current sheets

    NASA Technical Reports Server (NTRS)

    Weimer, D. R.; Gurnett, D. A.; Goertz, C. K.; Menietti, J. D.; Burch, J. L.

    1987-01-01

    The current-voltage relation within narrow auroral current sheets is examined through the use of high-resolution data from the high altitude Dynamics Explorer 1 satellite. The north-south perpendicular electric field and the east-west magnetic field are shown for three cases in which there are large amplitude, oppositely directed paired electric fields and narrow current sheets. These data are shown to indicate that there is a linear Ohm's law relationship between the current density and the parallel potential drop within the narrow current sheets. This linear relationship had previously been verified for large-scale auroral formations greater than 20 km wide at the ionosphere. The evidence shown here extends our knowledge down to the scale size of discrete auroral arcs.

  17. High current, high bandwidth laser diode current driver

    NASA Technical Reports Server (NTRS)

    Copeland, David J.; Zimmerman, Robert K., Jr.

    1991-01-01

    A laser diode current driver has been developed for free space laser communications. The driver provides 300 mA peak modulation current and exhibits an optical risetime of less than 400 ps. The current and optical pulses are well behaved and show minimal ringing. The driver is well suited for QPPM modulation at data rates up to 440 Mbit/s. Much previous work has championed current steering circuits; in contrast, the present driver is a single-ended on/off switch. This results in twice the power efficiency as a current steering driver. The driver electrical efficiency for QPPM data is 34 percent. The high speed switch is realized with a Ku-band GaAsFET transistor, with a suitable pre-drive circuit, on a hybrid microcircuit adjacent to the laser diode.

  18. DC-Compensated Current Transformer.

    PubMed

    Ripka, Pavel; Draxler, Karel; Styblíková, Renata

    2016-01-01

    Instrument current transformers (CTs) measure AC currents. The DC component in the measured current can saturate the transformer and cause gross error. We use fluxgate detection and digital feedback compensation of the DC flux to suppress the overall error to 0.15%. This concept can be used not only for high-end CTs with a nanocrystalline core, but it also works for low-cost CTs with FeSi cores. The method described here allows simultaneous measurements of the DC current component. PMID:26805830

  19. Currents in the cometary atmosphere

    NASA Technical Reports Server (NTRS)

    Ip, W.-H.

    1979-01-01

    If the structure of the magnetic field and electric current in the cometary type I tail can be represented by an electric current circuit, disruption of the cross-tail current system may lead to a current discharging through the cometary ionosphere, and the dissipation of the magnetic energy stored in the tail. From the point of view of energy budget, a tail-aligned magnetic field on the order of 10 gamma will be sufficient to produce a strong ionization effect of the cometary atmosphere.

  20. Mean currents and current variability in the iceland basin

    NASA Astrophysics Data System (ADS)

    Van Aken, Hendrik M.

    Long-term (>6 months) current measurements from five moorings in the Iceland Basin have been analysed for the mean currents and the structure of the variable current components. The time-averaged flow at all five moorings had a strong baroclinic character. The mean circulation in the upper layers with relatively warm Sub-Polar Mode Water appears to have a general north-eastward direction with maximum mean velocities of 6 to 7 cm·s -1. In the bottom layer south of Iceland, where the cold Iceland-Scotland Overflow Water flows westwards along the topography in a Deep Northern Boundary Current, mean velocities of the order of 10 to 20 cm·s -1 have been observed. Over the deep slope of the Hatton Bank, water enters the Iceland Basin in a branch of the Deep Northern Boundary Current which has a cyclonic rotation sense in the Iceland Basin. The variable part of the current has been analysed by means of principal-component analysis. The current variations in the central Iceland Basin appear to have a mainly barotropic character while variations in the baroclinic flow of Iceland-Scotland Overflow Water contributed 10% or less to the total energy of the variable deep flow. Over the slope of the Hatton Bank the variable currents had a mainly baroclinic character with shear in both current speed and direction. Comparison of the geostrophic velocity with the mean Eulerian velocity has revealed that the σθ=27.725 kg·m -3 surface can be used adequately as level of non-motion for the geostrophic modelling of the flow along the Iceland and Hatton slopes. The mean westward geostrophic transport of ISOW south of Iceland relative to this reference surface amounted to 3.5 Sv, in agreement with existing independent estimates.

  1. Current North American Indian Periodicals.

    ERIC Educational Resources Information Center

    Blew, Carol Van Antwerp Holliday; And Others

    Approximately 150 newsletters, newspapers, and other periodicals are cited in this bibliography of current sources of information about or directed toward North American Indians. One-sentence descriptions of content, ordering information, and frequency of publication are provided. The majority of the periodicals cited emphasize current events of…

  2. Anomalous-viscosity current drive

    DOEpatents

    Stix, T.H.; Ono, M.

    1986-04-25

    The present invention relates to a method and apparatus for maintaining a steady-state current for magnetically confining the plasma in a toroidal magnetic confinement device using anomalous viscosity current drive. A second aspect of this invention relates to an apparatus and method for the start-up of a magnetically confined toroidal plasma.

  3. Method for critical current testing

    SciTech Connect

    Siddall, M.B.; Smathers, D.B.

    1989-03-01

    Superconducting critical current testing software was developed with four important features not feasible with analog test equipment. First, quasi-steady-state sample current conditions are achieved by incrementing sample current, followed by holding some milliseconds until the transient voltage decays before voltage sampling. Then the self-field correction from a helically wound sample is computed and subtracted from each sampled field reading. A copper wire inductively wound shunt which is used for quench protection has a constant measured resistance from which the shunt leakage current is computed and subtracted from the sample current by measuring the shunt voltage after each sample current reading. Finally, the critical current is recomputed from a least squares curve fit to the power law: E=A*In when the correlation coefficient for the fit is high enough to ensure a better result than the raw datum. Comparison with NBS Standard Reference Material (NbTi) and current round robin Nb/sub 3/Sn testing is examined.

  4. Current in wave driven plasmas

    SciTech Connect

    Karney, C.F.F.; Fisch, N.J.

    1985-06-01

    A theory for the generation of current in a toroidal plasma by radio-frequency waves is presented. The effect of an opposing electric field is included, allowing the case of time varying currents to be studied. The key quantities that characterize this regime are identified and numerically calculated. Circuit equations suitable for use in ray-tracing and transport codes are given.

  5. Nonsinusoidal current and current reversals in a gating ratchet

    NASA Astrophysics Data System (ADS)

    Dinis, Luis; Quintero, Niurka R.

    2015-03-01

    In this work, the ratchet dynamics of Brownian particles driven by an external sinusoidal (harmonic) force is investigated. The gating ratchet effect is observed when another harmonic is used to modulate the spatially symmetric potential in which the particles move. For small amplitudes of the harmonics, it is shown that the current (average velocity) of particles exhibits a sinusoidal shape as a function of a precise combination of the phases of both harmonics. By increasing the amplitudes of the harmonics beyond the small-limit regime, departures from the sinusoidal behavior are observed and current reversals can also be induced. These current reversals persist even for the overdamped dynamics of the particles.

  6. Equatorial potassium currents in lenses.

    PubMed

    Wind, B E; Walsh, S; Patterson, J W

    1988-02-01

    Earlier work with the vibrating probe demonstrated the existence of outward potassium currents at the equator and inward sodium currents at the optical poles of the lens. By adding microelectrodes to the system, it is possible to relate steady currents (J) to the potential difference (PD) measured with a microelectrode. By injecting an outward current (I), it is possible to determine resistances and also the PD at which the steady outward potassium current becomes zero (PDJ = 0). At this PD the concentration gradient for potassium efflux and the electrical gradient for potassium influx are balanced so that there is no net flow of potassium across the membranes associated with the production of J. The PDJ = 0 for 18 rat lenses was 86 mV and that for 12 frogs lenses was -95 mV. This agrees with the potassium equilibrium potential and provides strong evidence to support the view that the outward equatorial current, J, is a potassium current. With the injection of outward current, I, the PD becomes more negative, the outward equatorial current, J, decreases, and the inward current at the optical poles increases. This suggests that there are separate electrical loops for K+ and Na+ that are partially linked by the Na, K-pump. Using Ohm's law, it is possible to calculate the input resistance (R = delta PD/I), the resistance related to the production of J (RJ = delta PD/delta J), and the effect of the combined resistances (delta J/I). The driving force for J can be estimated (PDJ = 0-PD). The relationships among currents, voltages and resistance can be used to determine the characteristics of the membranes that are associated with the outward potassium current observed at the equator. The effects of graded deformation of the lens were determined. The effects were reversible. The sites of inward and outward currents were not altered. Following deformation, the equatorial current, J, increased, and the PD became less negative. The PDJ = 0 remains the same so the ratio of K

  7. METHOD OF PEAK CURRENT MEASUREMENT

    DOEpatents

    Baker, G.E.

    1959-01-20

    The measurement and recording of peak electrical currents are described, and a method for utilizing the magnetic field of the current to erase a portion of an alternating constant frequency and amplitude signal from a magnetic mediums such as a magnetic tapes is presented. A portion of the flux from the current carrying conductor is concentrated into a magnetic path of defined area on the tape. After the current has been recorded, the tape is played back. The amplitude of the signal from the portion of the tape immediately adjacent the defined flux area and the amplitude of the signal from the portion of the tape within the area are compared with the amplitude of the signal from an unerased portion of the tape to determine the percentage of signal erasure, and thereby obtain the peak value of currents flowing in the conductor.

  8. Current Drive in Recombining Plasma

    SciTech Connect

    P.F. Schmit and N.J. Fisch

    2012-05-15

    The Langevin equations describing the average collisional dynamics of suprathermal particles in nonstationary plasma remarkably admit an exact analytical solution in the case of recombining plasma. The current density produced by arbitrary particle fluxes is derived including the effect of charge recombination. Since recombination has the effect of lowering the charge density of the plasma, thus reducing the charged particle collisional frequencies, the evolution of the current density can be modified substantially compared to plasma with fixed charge density. The current drive efficiency is derived and optimized for discrete and continuous pulses of current, leading to the discovery of a nonzero "residual" current density that persists indefinitely under certain conditions, a feature not present in stationary plasmas.

  9. Relationships between the Birkeland currents, ionospheric currents, and electric fields

    NASA Technical Reports Server (NTRS)

    Bleuler, E.; Li, C. H.; Nisbet, J. S.

    1982-01-01

    Currents and electric fields in the ionosphere are calculated using a global model of the electron density including conjugate coupling along field lines. Incoherent scatter and rocket measurements of high-latitude electron densities are used to derive realistic variations of the polar conductivities as a function of magnetic activity. The Birkeland currents are specified in terms of three indices, and the relationship between these parameters and the auroral electrojets indices is examined along with the polar cap potential and the electric field at lower latitudes. A mathematical model of the currents, electric fields, and energy inputs produced by field aligned currents is developed, which is consistent with and specifiable in terms of measured geophysical indices.

  10. Current-Produced Magnetic Field Effects on Current Collection

    NASA Technical Reports Server (NTRS)

    Khazanov, George V.; Stone, N. H.; Whitaker, Ann F. (Technical Monitor)

    2002-01-01

    Current collection by an infinitely long, conducting cylinder in a magnetized plasma, taking into account the magnetic field of the collected current, is discussed. A region of closed magnetic surfaces disconnects the cylinder from infinity. Due to this, the collected current depends on the ratio between this region and the plasma sheath region and, under some conditions, current reduction arises. The current collection along a realistic "bare wire" space tether is considered. A number of factors are taken into account, including the resistance of the wire and shielding resulting from the current-induced magnetic field produced by current flow in the tether. The plasma density, tether length and radius, the geomagnetic field strength and angle to the orbital velocity vector were all used as parameters in the study. It is shown that magnetic shielding for certain tether system configurations, when combined with particular values of the governing parameters, significantly reduces the collected current. Specifically, it is shown that an electrodynamic tether in the "thruster" mode suffers greater reduction from magnetic shielding than a tether with the same characteristics deployed in the "generator" mode. We find that, for both modes, current-induced magnetic shielding becomes more significant as plasma density and wire radius increase. The same is true for the dependence on the angle of the geomagnetic field to the orbital velocity vector and the motion-induced electric field for the generator mode For the thruster mode, the effect is larger for smaller angles. In both operating modes, the shielding is more important for smaller angles between the tether and magnetic field. In addition to the above dependencies, the effect for the thruster mode essentially depends on the tether length. In general, any parametric change that increases tether current, relative to the strength of the electric field between the tether and the ambient plasma, will increase the shielding

  11. Passive fault current limiting device

    DOEpatents

    Evans, D.J.; Cha, Y.S.

    1999-04-06

    A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment. 6 figs.

  12. Passive fault current limiting device

    DOEpatents

    Evans, Daniel J.; Cha, Yung S.

    1999-01-01

    A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment.

  13. Lightning current waveform measuring system

    NASA Technical Reports Server (NTRS)

    Wojtasinski, R. J.; Fuchs, J. C.; Grove, C. H. (Inventor)

    1978-01-01

    An apparatus is described for monitoring current waveforms produced by lightning strikes which generate currents in an elongated cable. These currents are converted to voltages and to light waves for being transmitted over an optical cable to a remote location. At the remote location, the waves are reconstructed back into electrical waves for being stored into a memory. The information is stored within the memory with a timing signal so that only different signals need be stored in order to reconstruct the wave form.

  14. On transport-driven currents

    NASA Astrophysics Data System (ADS)

    Ma, Sifeng; Dawson, John M.

    1994-08-01

    An empirical electron viscosity is incorporated into Ohm's law to examine the effect of current diffusion on bootstrap currents. It is shown that for sufficiently large viscosity, no seed current is needed for steady state operation of tokamaks. This is expressed by the scaling law ΓR2m=4/27 where Rm is the magnetic Reynolds number and Γ is viscosity normalized to νeia2 (νei is the electron-ion collision frequency and a is the system size).

  15. Currents in monterey submarine canyon

    USGS Publications Warehouse

    Xu, J. P.; Noble, M.A.

    2009-01-01

    Flow fields of mean, subtidal, and tidal frequencies between 250 and 3300 m water depths in Monterey Submarine Canyon are examined using current measurements obtained in three yearlong field experiments. Spatial variations in flow fields are mainly controlled by the topography (shape and width) of the canyon. The mean currents flow upcanyon in the offshore reaches (>1000 m) and downcanyon in the shallow reaches (100-m amplitude isotherm oscillations and associated high-speed rectilinear currents. The 15-day spring-neap cycle and a ???3-day??? band are the two prominent frequencies in subtidal flow field. Neither of them seems directly correlated with the spring-neap cycle of the sea level.

  16. Rugged Direct-Current Transducer

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1991-01-01

    Direct-current transducer withstands thermal and mechanical shocks. Operates from single, nominally 15-V power supply and nearly insensitive to both large variations in temperature and variations of as much as plus or minus 5 V in supply voltage. Its output voltage highly linear function of sensed current, with full-scale value of about 3 Vdc and offset of about 0.1 Vdc at 0 sensed current. Ruggedness of transducer due in large part to novel magnetic core, machined from solid block of nickel/iron high-permeability, low-hysteresis alloy.

  17. Current balancing for battery strings

    DOEpatents

    Galloway, James H.

    1985-01-01

    A battery plant is described which features magnetic circuit means for balancing the electrical current flow through a pluraliircuitbattery strings which are connected electrically in parallel. The magnetic circuit means is associated with the battery strings such that the conductors carrying the electrical current flow through each of the battery strings pass through the magnetic circuit means in directions which cause the electromagnetic fields of at least one predetermined pair of the conductors to oppose each other. In an alternative embodiment, a low voltage converter is associated with each of the battery strings for balancing the electrical current flow through the battery strings.

  18. Current in open quantum systems.

    PubMed

    Gebauer, Ralph; Car, Roberto

    2004-10-15

    We show that a dissipative current component is present in the dynamics generated by a Liouville-master equation, in addition to the usual component associated with Hamiltonian evolution. The dissipative component originates from coarse graining in time, implicit in a master equation, and needs to be included to preserve current continuity. We derive an explicit expression for the dissipative current in the context of the Markov approximation. Finally, we illustrate our approach with a simple numerical example, in which a quantum particle is coupled to a harmonic phonon bath and dissipation is described by the Pauli master equation. PMID:15524960

  19. Surface currents on ideal plasmas

    SciTech Connect

    Webster, Anthony J.

    2010-11-15

    The surface (or 'skin') current that can flow at a perturbed interface between plasma and vacuum is considered in the approximation where a surface marks a sharp transition from plasma to vacuum. A short magnetohydrodynamic calculation gives an exact and general expression for the component perpendicular to the average of the magnetic field either side of the surface, finding it proportional to the edge plasma pressure. A consequence is that for all plasmas with zero surface current at equilibrium, the surface current associated with any linear instability will flow parallel to the magnetic field. The surface current is calculated for a simple but realistic model of a cylindrical plasma, and found to depend on the type of instability, and consequently on the particular plasma equilibrium. This is illustrated for two well known cases.

  20. Geomagnetically Induced Currents From Reconnection

    NASA Video Gallery

    This animations shows a coronal mass ejections collide with Earth's magnetic fields and the fields change shape and strength. Reconnection in the magnetotail causes currents to follow the field lin...

  1. Magneto-optic current sensor

    DOEpatents

    Lanagan, Michael T.; Valsko-Vlasov, Vitalii K.; Fisher, Brandon L.; Welp, Ulrich

    2003-10-07

    An optical current transducer configured to sense current in the conductor is disclosed. The optical current transducer includes a light source and a polarizer that generates linearly polarized light received from a the light source. The light is communicated to a magneto-optic garnet that includes, among other elements, bismuth, iron and oxygen and is coupled to the conductor. The magneto-optic garnet is configured to rotate the polarization of the linearly polarized light received from the polarizer. The optical current transducer also includes an analyzer in optical communication with the magneto-optic garnet. The analyzer detects the rotation of the linearly polarized light caused by the magneto-optic garnet.

  2. Current projects in Fuzzy Control

    NASA Technical Reports Server (NTRS)

    Sugeno, Michio

    1990-01-01

    Viewgraphs on current projects in fuzzy control are presented. Three projects on helicopter flight control are discussed. The projects are (1) radio control by oral instructions; (2) automatic autorotation entry in engine failure; and (3) unmanned helicopter for sea rescue.

  3. High current gain transistor laser.

    PubMed

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-01-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge. PMID:27282466

  4. LANSCE Beam Current Limiter (XL)

    SciTech Connect

    Gallegos, F.R.; Hall, M.J.

    1997-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) is an engineered safety system that provides personnel protection from prompt radiation due to accelerated proton beams. The Beam Current Limiter (XL), as an active component of the RSS, limits the maximum average current in a beamline, thus the current available for a beam spill accident. Exceeding the pre-set limit initiates action by the RSS to mitigate the hazard (insertion of beam stoppers in the low energy beam transport). The beam limiter is an electrically isolated, toroidal transformer and associated electronics. The device was designed to continuously monitor beamline currents independent of any external timing. Fail-safe operation was a prime consideration in its development. Fail-safe operation is defined as functioning as intended (due to redundant circuitry), functioning with a more sensitive fault threshold, or generating a fault condition. This report describes the design philosophy, hardware, implementation, operation, and limitations of the device.

  5. Optimal Current Transfer in Dendrites

    PubMed Central

    Bird, Alex D.

    2016-01-01

    Integration of synaptic currents across an extensive dendritic tree is a prerequisite for computation in the brain. Dendritic tapering away from the soma has been suggested to both equalise contributions from synapses at different locations and maximise the current transfer to the soma. To find out how this is achieved precisely, an analytical solution for the current transfer in dendrites with arbitrary taper is required. We derive here an asymptotic approximation that accurately matches results from numerical simulations. From this we then determine the diameter profile that maximises the current transfer to the soma. We find a simple quadratic form that matches diameters obtained experimentally, indicating a fundamental architectural principle of the brain that links dendritic diameters to signal transmission. PMID:27145441

  6. Remote sensing of ocean currents

    NASA Technical Reports Server (NTRS)

    Goldstein, R. M.; Zebker, H. A.; Barnett, T. P.

    1989-01-01

    A method of remotely measuring near-surface ocean currents with a synthetic aperture radar (SAR) is described. The apparatus consists of a single SAR transmitter and two receiving antennas. The phase difference between SAR image scenes obtained from the antennas forms an interferogram that is directly proportional to the surface current. The first field test of this technique against conventional measurements gives estimates of mean currents accurate to order 20 percent, that is, root-mean-square errors of 5 to 10 centimeters per second in mean flows of 27 to 56 centimeters per second. If the full potential of the method could be realized with spacecraft, then it might be possible to routinely monitor the surface currents of the world's oceans.

  7. High current gain transistor laser

    NASA Astrophysics Data System (ADS)

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-06-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge.

  8. Magnetic tape lightning current detectors

    NASA Technical Reports Server (NTRS)

    Crouch, K. E.; Jafferis, W.

    1980-01-01

    Development and application tests of a low cost, passive, peak lightning current detector (LCD) found it to provide measurements with accuracies of + or - 5 percent to + or - 10 percent depending on the readout method employed. The LCD uses magnetic audio recording tape to sense the magnitude of the peak magnetic field around a conductor carrying lightning currents. The test results showed that the length of audio tape erased was linearly related to the peak simulated lightning currents in a round conductor. Accuracies of + or - 10 percent were shown for measurements made using a stopwatch readout technique to determine the amount of tape erased by the lightning current. Where more accurate data are desired, the tape is played and the output recorded on a strip chart, oscilloscope, or some other means so that measurements can be made on that recording. Conductor dimensions, tape holder dimensions, and tape formulation must also be considered to obtain a more accurate result.

  9. Electric current abroad, 1991 edition

    NASA Astrophysics Data System (ADS)

    1991-07-01

    The characteristics are listed, for the information of U.S. manufacturers and exporters and individuals living or traveling abroad, of electric current available and the type of attachment plugs used in principal cities throughout the world. The characteristics of electric current-type (alternating or direct current), number of phases, frequency (hertz), and voltage found in major foreign cities are listed. In addition, the stability of the frequency and the number of wires to a commercial or residential installation are given where available. The current characteristics and other data furnished relate to domestic and commercial service only. It does not include special commercial installations involving relatively high voltage requirements nor does it refer to any industrial installations.

  10. Current Fat Guidelines and Recommendations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current dietary guidelines, including those of the US government [Dietary Guidelines (USDA/DHHS, 2005), Dietary Reference Intakes [reference DRI macronutrient book], National Cholesterol Education Program (NCEP, 2001)], American Heart Association (AHA, 2206), American Diabetes Association (2006) and...

  11. High current gain transistor laser

    PubMed Central

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-01-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge. PMID:27282466

  12. Ozone - Current Air Quality Index

    MedlinePlus

    ... reducing exposure to extremely high levels of particle pollution is available here . Fires: Current Conditions Click to ... Air Quality Basics Air Quality Index | Ozone | Particle Pollution | Smoke from fires | What You Can Do Health ...

  13. Surface Electromigration and Current Crowding

    NASA Astrophysics Data System (ADS)

    Yongsunthon, R.; Tao, C.; Rous, P.; Williams, E. D.

    Steps on macroscopic surfaces provide a useful model system for quantifying electron scattering at defects in nanostructures, where the large surface/volume ratio will cause surface effects to dominate. Here, the effects of electron scattering at surface steps are quantified using thin silver films with (111) surface orientation. Using real-time scanning tunneling microscopy (STM) measurements while large current densities are applied to the films, changes in step fluctuations and island motion are observed and quantified. Applying the tools of the continuum step model, the observations are analyzed in terms of step free energies and kinetics, yielding quantitative values of the electromigration force driving the observed mass displacements. The derived magnitudes are surprisingly large in comparison with classical calculations of the force due to electron scattering at the internal surface of a conductor. This result indicates that the specific atomistic characteristics of the scattering sites, in this case kinks at the step edge, may greatly enhance the electromigration force. Within the classical ballistic picture of ballistic momentum transfer, specific mechanisms for such enhancement include enhanced geometric "blocking" at the kinked step edges, changes in carrier density near kinks, and current crowding. Quantum transmission effects at atomic-scale defect sites may also be responsible for the observed enhancement. The nature of classical current crowding as a function of the shape and size of defect was characterized using magnetic force microscopy (MFM) of fabricated micron-scale model structures. Techniques were developed to remove the effects of instrumental broadening using deconvolution, so that full three-dimensional maps of the magnetic fields above the current line are determined. A Green function inversion technique is then used to invert the field distribution to determine the spatial variations in the current density in the sample. Current

  14. Ohmic currents and predecoupling magnetism

    SciTech Connect

    Giovannini, Massimo; Nguyen Quynh Lan

    2009-07-15

    Ohmic currents induced prior to decoupling are investigated in a standard transport model accounting both for the expansion of the background geometry as well as of its relativistic inhomogeneities. The relative balance of the Ohmic electric fields in comparison with the Hall and thermoelectric contributions is specifically addressed. The impact of the Ohmic currents on the evolution of curvature perturbations is discussed numerically and it is shown to depend explicitly upon the evolution of the conductivity.

  15. electromagnetics, eddy current, computer codes

    Energy Science and Technology Software Center (ESTSC)

    2002-03-12

    TORO Version 4 is designed for finite element analysis of steady, transient and time-harmonic, multi-dimensional, quasi-static problems in electromagnetics. The code allows simulation of electrostatic fields, steady current flows, magnetostatics and eddy current problems in plane or axisymmetric, two-dimensional geometries. TORO is easily coupled to heat conduction and solid mechanics codes to allow multi-physics simulations to be performed.

  16. Spheromak Impedance and Current Amplification

    SciTech Connect

    Fowler, T K; Hua, D D; Stallard, B W

    2002-01-31

    It is shown that high current amplification can be achieved only by injecting helicity on the timescale for reconnection, {tau}{sub REC}, which determines the effective impedance of the spheromak. An approximate equation for current amplification is: dI{sub TOR}{sup 2}/dt {approx} I{sup 2}/{tau}{sub REC} - I{sub TOR}{sup 2}/{tau}{sub closed} where I is the gun current, I{sub TOR} is the spheromak toroidal current and {tau}{sub CLOSED} is the ohmic decay time of the spheromak. Achieving high current amplification, I{sub TOR} >> I, requires {tau}{sub REC} <<{tau}{sub CLOSED}. For resistive reconnection, this requires reconnection in a cold zone feeding helicity into a hot zone. Here we propose an impedance model based on these ideas in a form that can be implemented in the Corsica-based helicity transport code. The most important feature of the model is the possibility that {tau}{sub REC} actually increases as the spheromak temperature increases, perhaps accounting for the ''voltage sag'' observed in some experiments, and a tendency toward a constant ratio of field to current, B {proportional_to} I, or I{sub TOR} {approx} I. Program implications are discussed.

  17. Multispacecraft current estimates at swarm

    NASA Astrophysics Data System (ADS)

    Dunlop, M. W.; Yang, Y.-Y.; Yang, J.-Y.; Lühr, H.; Shen, C.; Olsen, N.; Ritter, P.; Zhang, Q.-H.; Cao, J.-B.; Fu, H.-S.; Haagmans, R.

    2015-10-01

    During the first several months of the three-spacecraft Swarm mission all three spacecraft came repeatedly into close alignment, providing an ideal opportunity for validating the proposed dual-spacecraft method for estimating current density from the Swarm magnetic field data. Two of the Swarm spacecraft regularly fly side-by-side in closely similar orbits, while the third at times approaches the other two. This provides a data set which under certain assumptions of stationarity of the magnetic field can produce 2, 3, 4, 5 (or more) point measurements, which can be cross compared. We find that at low Earth orbit the use of time-shifted positions allow stable estimates of current density to be made and can verify temporal effects as well as validating the interpretation of the current components as arising predominantly from field-aligned currents. In the case of four-spacecraft configurations we can resolve the full vector current and therefore can check the perpendicular as well as parallel current density components directly, together with the quality factor for the estimates directly (for the first time in situ at low Earth orbit).

  18. BOOK REVIEW: The Current Comparator

    NASA Astrophysics Data System (ADS)

    Petersons, Oskars

    1989-01-01

    This 120-page book is a concise, yet comprehensive, clearly-written and well-illustrated monograph that covers the subject matter from basic principles through design, construction and calibration details to the principal applications. The book will be useful, as a primer, to the uninitiated and, as a reference book to the practitioner involved with transformer-type ratio devices. The length of the book and the style of presentation will not overburden any informed reader. The described techniques and the cited references are primarily from the work at the National Research Council, Canada (NRC). Any omissions, however, are not serious with respect to coverage of the subject matter, since most of the development work has been done at NRC. The role of transformers and transformer-like devices for establishing accurate voltage and current ratios has been recognized for over half a century. Transformer techniques were much explored and developed in the fifties and sixties for accuracy levels suitable for standards laboratories. Three-winding voltage transformers were developed for scaling of impedances in connection with the calculable Thompson Lampard capacitor; three-winding current transformers or current comparators were initially explored for the calibration of current transformers and later for specialized impedance measurements. Extensive development of the current comparator and its applications has been and is still being conducted at the NRC by a team that was started and, until his retirement, led by N L Kusters. The team is now led by W J M Moore. He and P N Miljanic, the authors of this book, have had the principal roles in the development of the current comparator. It is fortunate for the field of metrology that considerabe resources and a talented group of researchers were available to do this development along with mechanisms that were available to transfer this technology to a private sector instrument manufacturer and, thus, disseminate it world wide

  19. Efficient and lightweight current leads

    NASA Astrophysics Data System (ADS)

    Bromberg, L.; Dietz, A. J.; Michael, P. C.; Gold, C.; Cheadle, M.

    2014-01-01

    Current leads generate substantial cryogenic heat loads in short length High Temperature Superconductor (HTS) distribution systems. Thermal conduction, as well as Joule losses (I2R) along the current leads, comprises the largest cryogenic loads for short distribution systems. Current leads with two temperature stages have been designed, constructed and tested, with the goal of minimizing the electrical power consumption, and to provide thermal margin for the cable. We present the design of a two-stage current lead system, operating at 140 K and 55 K. This design is very attractive when implemented with a turbo-Brayton cycle refrigerator (two-stage), with substantial power and weight reduction. A heat exchanger is used at each temperature station, with conduction-cooled stages in-between. Compact, efficient heat exchangers are challenging, because of the gaseous coolant. Design, optimization and performance of the heat exchangers used for the current leads will be presented. We have made extensive use of CFD models for optimizing hydraulic and thermal performance of the heat exchangers. The methodology and the results of the optimization process will be discussed. The use of demountable connections between the cable and the terminations allows for ease of assembly, but require means of aggressively cooling the region of the joint. We will also discuss the cooling of the joint. We have fabricated a 7 m, 5 kA cable with second generation HTS tapes. The performance of the system will be described.

  20. Current drive by helicon waves

    SciTech Connect

    Paul, Manash Kumar; Bora, Dhiraj

    2009-01-01

    Helicity in the dynamo field components of helicon wave is examined during the novel study of wave induced helicity current drive. Strong poloidal asymmetry in the wave magnetic field components is observed during helicon discharges formed in a toroidal vacuum chamber of small aspect ratio. High frequency regime is chosen to increase the phase velocity of helicon waves which in turn minimizes the resonant wave-particle interactions and enhances the contribution of the nonresonant current drive mechanisms. Owing to the strong poloidal asymmetry in the wave magnetic field structures, plasma current is driven mostly by the dynamo-electric-field, which arise due to the wave helicity injection by helicon waves. Small, yet finite contribution from the suppressed wave-particle resonance cannot be ruled out in the operational regime examined. A brief discussion on the parametric dependence of plasma current along with numerical estimations of nonresonant components is presented. A close agreement between the numerical estimation and measured plasma current magnitude is obtained during the present investigation.

  1. Variable current speed controller for eddy current motors

    DOEpatents

    Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.

    1982-03-12

    A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

  2. Current pulse shaping of the load current on PTS

    NASA Astrophysics Data System (ADS)

    Xia, Minghe; Li, Fengping; Ji, Ce; Wei, Bing; Feng, Shuping; Wang, Meng; Xie, Weiping

    2016-02-01

    The typical rise time of PTS machine is ˜110 ns with about 10 MA peak current under short pulse mode when all 24 modules discharge simultaneously. By distributing the trigger times of 12 laser beams logically and adjusting the statues of the pulse output switches, longer rise-time pulse can be obtained on the PTS facility. Based on the required pulse shape, whole circuit simulations will be used to calculate the trigger times of each laser triggering gas switch and the status of the pulse output switches. The rise time of the current is determined by the time difference between the first and last trigged laser triggering gas switches. In order to trigger the laser triggering gas switch, sufficient laser power is needed to be sent into the gap of the gas switches. The gas pressure and voltage difference on the two electrodes of the gas switches also affect the triggering of the gas switches, and the voltage added on the gas switch is determined by its transition time. Traditionally the trigger time difference should be less than the transition time of the two neighboring modules. A new simulation model of PTS shows one can break this transition time limits. Series of current pulse shaping experiments have been investigated on the PTS (Primary Test Stand). As results, more than 5 MA peak current were successfully achieved on the load with a rise time of 600 ns. This study and experiments of the pulse shaping on PTS demonstrate the adaptable ability of the PTS for offering different waveform of mega ampere current pulse for different research purpose.

  3. Eddy current scanning at Fermilab

    SciTech Connect

    Boffo, C.; Bauer, P.; Foley, M.; Brinkmann, A.; Ozelis, J.; /Jefferson Lab

    2005-07-01

    In the framework of SRF cavity development, Fermilab is creating the infrastructure needed for the characterization of the material used in the cavity fabrication. An important step in the characterization of ''as received'' niobium sheets is the eddy current scanning. Eddy current scanning is a non-destructive technique first adopted and further developed by DESY with the purpose of checking the cavity material for sub-surface defects and inclusions. Fermilab has received and further upgraded a commercial eddy current scanner previously used for the SNS project. The upgrading process included developing new filtering software. This scanner is now used daily to scan the niobium sheets for the Fermilab third harmonic and transverse deflecting cavities. This paper gives a status report on the scanning results obtained so far, including a discussion of the typology of signals being detected. We also report on the efforts to calibrate this scanner, a work conducted in collaboration with DESY.

  4. Ion currents in embryo development.

    PubMed

    Tosti, Elisabetta; Boni, Raffaele; Gallo, Alessandra

    2016-03-01

    Ion channels are proteins expressed in the plasma membrane of electrogenic cells. In the zygote and blastomeres of the developing embryo, electrical modifications result from ion currents that flow through these channels. This phenomenon implies that ion current activity exerts a specific developmental function, and plays a crucial role in signal transduction and the control of embryogenesis, from the early cleavage stages and during growth and development of the embryo. This review describes the involvement of ion currents in early embryo development, from marine invertebrates to human, focusing on the occurrence, modulation, and dynamic role of ion fluxes taking place on the zygote and blastomere plasma membrane, and at the intercellular communication between embryo cell stages. Birth Defects Research (Part C) 108:6-18, 2016. © 2016 Wiley Periodicals, Inc. PMID:26989869

  5. Modeling photoelectron currents through gases

    NASA Astrophysics Data System (ADS)

    Wyatt, A. F. G.

    2007-06-01

    We reexamine the processes involved in a current flowing from a photocathode, through a gas, to a collector at a positive voltage. The current is determined by the electrons being scattered back to the photocathode as well as by the transport through the gas. We find that the current, as a function of gas pressure and applied electric field, is reasonably well described by Thomson’s equation if the velocities of the electrons are correctly defined and the measured scattering cross sections are used. At low pressures, the relevant electron energy is the emitted energy from the photocathode, as suggested by Loeb [The Kinetic Theory of Gases (McGraw-Hill, New York, 1934), p. 625]. At high pressures, the electrons that return to the photocathode are thermalized; while in the gas, the electrons have an extra energy from the electric field.

  6. Magnetoelectric control of spin currents

    NASA Astrophysics Data System (ADS)

    Gómez, J. E.; Vargas, J. M.; Avilés-Félix, L.; Butera, A.

    2016-06-01

    The ability to control the spin current injection has been explored on a hybrid magnetoelectric system consisting of a (011)-cut ferroelectric lead magnesium niobate-lead titanate (PMNT) single crystal, a ferromagnetic FePt alloy, and a metallic Pt. With this PMNT/FePt/Pt structure we have been able to control the magnetic field position or the microwave excitation frequency at which the spin pumping phenomenon between FePt and Pt occurs. We demonstrate that the magnetoelectric heterostructure operating in the L-T (longitudinal magnetized-transverse polarized) mode couples the PMNT crystal to the magnetostrictive FePt/Pt bilayer, displaying a strong magnetoelectric coefficient of ˜140 Oe cm kV-1. Our results show that this mechanism can be effectively exploited as a tunable spin current intensity emitter and open the possibility to create an oscillating or a bistable switch to effectively manipulate spin currents.

  7. Electric currents in cosmic plasmas

    NASA Technical Reports Server (NTRS)

    Alfven, H.

    1977-01-01

    It is suggested that dualism is essential for the physics of cosmic plasmas, that is, that some phenomena should be described by a magnetic field formalism, and others by an electric current formalism. While in earlier work the magnetic field aspect has dominated, at present there is a systematic exploration of the particle (or current) aspect. A number of phenomena which can be understood only from the particle aspect are surveyed. Topics include the formation of electric double layers, the origin of 'explosive' events like magnetic substorms and solar flares, and the transfer of energy from one region to another. A method for exploring many of these phenomena is to draw the electric circuit in which the current flows and then study its properties. A number of simple circuits are analyzed in this way.

  8. Transungual drug delivery: current status.

    PubMed

    Elkeeb, Rania; AliKhan, Ali; Elkeeb, Laila; Hui, Xiaoying; Maibach, Howard I

    2010-01-15

    Topical therapy is highly desirable in treating nail disorders due to its localized effects, which results in minimal adverse systemic events and possibly improved adherence. However, the effectiveness of topical therapies is limited by minimal drug permeability through the nail plate. Current research on nail permeation that focuses on altering the nail plate barrier by means of chemical treatments, penetration enhancers as well as physical and mechanical methods is reviewed. A new method of nail sampling is examined. Finally limitations of current ungual drug permeability studies are briefly discussed. PMID:19819318

  9. Current issues with research support

    SciTech Connect

    Russell, W.T.

    1996-03-01

    It would be difficult to condense current issues in nuclear reactor regulation to just a few minutes. So, let me start off by saying that I have not tried to give a comprehensive listing of issues that are currently facing the reactor program, but rather to select those that I thought were relevant as they relate to research activities. Use of probabilistic risk assessment in regulatory decisions; materials aging issues concerning steam generators and reactor vessels; high burnup fuels; accident management; and digital instrumentation and control, are just a sampling of the important issues that I want to talk about.

  10. Current Evidence for Osteoarthritis Treatments

    PubMed Central

    Anandacoomarasamy, Ananthila; March, Lyn

    2010-01-01

    Osteoarthritis (OA) is the most common form of arthritis and the leading cause of chronic disability among older people. The burden of the disease is expected to rise with an aging population and the increasing prevalence of obesity. Despite this, there is as yet no cure for OA. However, in recent years, a number of potential therapeutic advances have been made, in part due to improved understanding of the underlying pathophysiology. This review provides the current evidence for symptomatic management of OA including nonpharmacological, pharmacological and surgical approaches. The current state of evidence for disease-modifying therapy in OA is also reviewed. PMID:22870434

  11. Current therapies for premature ejaculation.

    PubMed

    Gur, Serap; Kadowitz, Philip J; Sikka, Suresh C

    2016-07-01

    Premature ejaculation (PE) subjectively affects 20-30% of men globally. Until recently, understanding of PE was hampered by the absence of a widely accepted definition, paucity of evidence-based clinical studies, and the absence of an appropriate animal model. Here, we elaborate on the current definition of PE, its pathogenesis, currently available therapies, and future treatment prospects. Most treatments for PE are 'off-label' and include selective serotonin reuptake inhibitors (SSRIs), topical anesthetics, tramadol, and phosphodiesterase type 5 (PDE5) inhibitors. Such knowledge of the benefit and limitations of each treatment will help to direct future drug design and formulations. PMID:27179987

  12. Nondestructive synchronous beam current monitor

    SciTech Connect

    Covo, Michel Kireeff

    2014-12-15

    A fast current transformer is mounted after the deflectors of the Berkeley 88-Inch Cyclotron. The measured signal is amplified and connected to the input of a lock-in amplifier. The lock-in amplifier performs a synchronous detection of the signal at the cyclotron second harmonic frequency. The magnitude of the signal detected is calibrated against a Faraday cup and corresponds to the beam intensity. It has exceptional resolution, long term stability, and can measure the beam current leaving the cyclotron as low as 1 nA.

  13. Tevatron Resistive Wall Current Monitor

    SciTech Connect

    Crisp, J.; Fellenz, B.; /Fermilab

    2011-01-01

    Resistive Wall Current Monitors (RWCM) were designed and built for the Fermilab Tevatron (Tev) project. These devices measure longitudinal beam current from 3 KHz to 6 GHz with 1.34 ohm gap impedance. There are two RWCM's installed a few feet apart in the Tevatron, upstream RWCM is used for general purpose use, downstream RWCM is dedicated for longitudinal parameters of coalesced beam bunches and bunch intensities. The design provides a calibration or test port for injecting test signals. Microwave absorber material is used to reduce interference from spurious electromagnetic waves traveling inside the beam pipe. This paper will do an overview how the RWCM was designed and its test results.

  14. Current Endoscopic Treatment of Dysphonia

    PubMed Central

    Ossoff, Robert H.

    2000-01-01

    Benign laryngeal disorders result in dysphonia because of effects on glottic closure and the vibratory characteristics of the true vocal fold. Treatment is initially directed at reversing medical conditions and patterns of abuse with surgery reserved for unresolving lesions resulting in troublesome dysphonia. Benign lesions that require surgery are excised as precisely as possible sparing overlying mucosa and the underlying vocal ligament. Vocal fold scarring is currently best treated by augmentation procedures, and atrophy may be compensated for by medialization thyroplasty or by adding bulk to the affected folds. Application of current knowledge of laryngeal histology and physiology is prerequisite to endoscopic surgical intervention. PMID:18493531

  15. Force As A Momentum Current

    SciTech Connect

    Munera, Hector A.

    2010-07-28

    Advantages of a neo-Cartesian approach to classical mechanics are noted. If conservation of linear momentum is the fundamental principle, Newton's three laws become theorems. A minor paradox in static Newtonian mechanics is identified, and solved by reinterpreting force as a current of momentum. Contact force plays the role of a mere midwife in the exchange of momentum; however, force cannot be eliminated from physics because it provides the numerical value for momentum current. In this sense, in a neo-Cartesian formulation of mechanics the concept of force becomes strengthened rather than weakened.

  16. Eddy current thickness measurement apparatus

    DOEpatents

    Rosen, Gary J.; Sinclair, Frank; Soskov, Alexander; Buff, James S.

    2015-06-16

    A sheet of a material is disposed in a melt of the material. The sheet is formed using a cooling plate in one instance. An exciting coil and sensing coil are positioned downstream of the cooling plate. The exciting coil and sensing coil use eddy currents to determine a thickness of the solid sheet on top of the melt.

  17. Current Status of Laboratory Studies.

    ERIC Educational Resources Information Center

    Liberty, Paul; And Others

    General information on the studies currently underway by the Southwestern Cooperative Educational Laboratory (SECEL) is presented in this report. Module A is concerned with investigating the relationships between a variety of cultural-psychological factors and language development in grade 1. Testing and home interviews play a major part in this…

  18. Current Perspectives in Distributive Education.

    ERIC Educational Resources Information Center

    Klaurens, Mary K., Ed.; Trapnell, Gail, Ed.

    The volume on current perspectives in distributive education contains 29 individually authored articles organized into three sections. The first section on program conceptualization deals with the following subjects: the evolution of distributive education, program planning, advisory committees, placement services, postsecondary distributive…

  19. Cutaneous melanoma: A current overview.

    PubMed

    Wick, Mark R

    2016-07-01

    Cutaneous melanoma continues to increase in frequency, for unknown reasons, and it can pose considerable diagnostic challenges to clinician and pathologists alike. This review considers current concepts pertaining to that tumor, including those concerning epidemiology, clinical diagnosis, histologic findings, adjunctive diagnostic studies, and prognosis. PMID:27229301

  20. Current Mode Logic Fan Out

    Energy Science and Technology Software Center (ESTSC)

    2011-05-07

    Current mode logic is used in high speed timing systems for particle accelerators due to the fast rise time of the electrical signal. This software provides the necessary documentation to produce multiple copies of a single input for distribution to multiple devices. This software supports the DOE mission by providing a method for producing high speed signals in accelerator timing systems.

  1. The Current in a Wire

    ERIC Educational Resources Information Center

    Thompson, Keith

    2009-01-01

    This little problem arose because I was frustrated with the standard electromagnetism texts, which show the magnetic field due to a current-bearing wire outside the wire [proportional to] 1/r and inside [proportional to] r. However, they never point out that the moving electrons must be influenced by the magnetic field created by the other moving…

  2. Intelligence Current in Creative Activities

    ERIC Educational Resources Information Center

    Shi, Jiannong

    2004-01-01

    In this paper, the term 'intelligence current' is further explained and the problems found in relationships between (among) creativity, intelligence, attitude and environmental factors are discussed, according to the systematic model of creativity previously developed by the author. In this model, the performance of an individual's creativity is…

  3. Current Issues Survey Report, 2007

    ERIC Educational Resources Information Center

    Camp, John S.; DeBlois, Peter B.

    2007-01-01

    The Eighth Annual EDUCAUSE Current Issues Survey asked campus information technology leaders to rate the most critical IT challenges facing them, their campuses, and/or their systems. Four findings associated with all respondents to this year's survey merit special mention. First, for the 2007 survey, the CIC decided to split a key issue choice…

  4. Inexpensive Eddy-Current Standard

    NASA Technical Reports Server (NTRS)

    Berry, Robert F., Jr.

    1985-01-01

    Radial crack replicas serve as evaluation standards. Technique entails intimately joining two pieces of appropriate aluminum alloy stock and centering drilled hole through and along interface. Bore surface of hole presents two vertical stock interface lines 180 degrees apart. These lines serve as radial crack defect replicas during eddy-current technique setup and verification.

  5. Low power consumption current transducer

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T. (Inventor)

    1989-01-01

    A low power consumption current transducer utilizes a saturable core reactor which includes a pair of opposed gate windings and a control winding. The control winding of the saturable reactor is arranged to receive the current to be measured. A square wave generator is connected to the gate winding of the transformer connected across the square wave generator and the secondary connected in series with the gate windings of the reactor. A full wave rectifier is connected to the gate windings and a resistor is connected across the rectifier to provide a DC voltage to cross it representative of the current flow through the control winding. A DC power supply is provided to supply power to the square wave voltage source. A diode is connected between each end of the primary winding of the transformer and one polarity of the DC power supply to commutate the reactive current resulting from the counter emf generated in the reactor back to the DC supply to eliminate potentially damaging reactive voltage spikes which would otherwise appear at the output of the square wave generator and conserve energy.

  6. Teen Addiction. Current Controversies Series.

    ERIC Educational Resources Information Center

    Winters, Paul A., Ed.

    The Current Controversies series explores social, political, and economic controversies that dominate the national and international scenes today from a variety of perspectives. Recent surveys have shown that, after years of decline, drug use among teenagers has increased during the 1990s, and that alcohol and tobacco use have remained…

  7. Current Research in Affective Development.

    ERIC Educational Resources Information Center

    Strayer, Janet

    1985-01-01

    Current research concerning affective development in infants and children is selectively reviewed. The focus of findings and discussion is on three general and related topics: (1) expression of emotion and affective interaction in infancy; (2) socialization and regulation of emotion; (3) comprehension of emotions and empathy with others by…

  8. Biodiesel: Current Trends and Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel, an alternative to petroleum-derived diesel fuel, is defined as the mono-alkyl esters of vegetable oils and animal fats. Several current issues affecting biodiesel that are briefly discussed include the role of new feedstocks in meeting increased demand for biodiesel and circumventing the...

  9. CURRENT POPULATION SURVEY NATIVITY SUPPLEMENT

    EPA Science Inventory

    The Current Population Survey (CPS) is a cross-sectional survey conducted with about 57,000 households every month, primarily to measure changes in the labor force. It is conducted by the U.S. Bureau of the Census and administered to panels of respondents, which revolve into the ...

  10. Universal bounds on current fluctuations

    NASA Astrophysics Data System (ADS)

    Pietzonka, Patrick; Barato, Andre C.; Seifert, Udo

    2016-05-01

    For current fluctuations in nonequilibrium steady states of Markovian processes, we derive four different universal bounds valid beyond the Gaussian regime. Different variants of these bounds apply to either the entropy change or any individual current, e.g., the rate of substrate consumption in a chemical reaction or the electron current in an electronic device. The bounds vary with respect to their degree of universality and tightness. A universal parabolic bound on the generating function of an arbitrary current depends solely on the average entropy production. A second, stronger bound requires knowledge both of the thermodynamic forces that drive the system and of the topology of the network of states. These two bounds are conjectures based on extensive numerics. An exponential bound that depends only on the average entropy production and the average number of transitions per time is rigorously proved. This bound has no obvious relation to the parabolic bound but it is typically tighter further away from equilibrium. An asymptotic bound that depends on the specific transition rates and becomes tight for large fluctuations is also derived. This bound allows for the prediction of the asymptotic growth of the generating function. Even though our results are restricted to networks with a finite number of states, we show that the parabolic bound is also valid for three paradigmatic examples of driven diffusive systems for which the generating function can be calculated using the additivity principle. Our bounds provide a general class of constraints for nonequilibrium systems.

  11. Physical origin of pickup currents

    NASA Astrophysics Data System (ADS)

    Vasyliūnas, V. M.

    2016-02-01

    So-called pickup electric currents, associated with the ionization of neutral particles in the presence of a flowing plasma, are conventionally described as produced directly by differential displacement of ions and electrons as the result of acceleration and gyromotion under the action of the electric field E = -V × B/c. This is not the appropriate physical description for the case when the electron inertial length of the background plasma is small in comparison with the spatial scale of the system. The pickup process in this case does not directly produce a current, except for a small transient on the electron-gyroperiod timescale, which then decays exponentially at the ionization (momentum-loading) rate, as can be shown by an explicit solution of the equations. Rather, the plasma is first slowed down by the momentum loading; the spatially inhomogeneous velocity change then leads to a perturbation of the magnetic field, and the curl of the perturbed field is the current. The timescale for the development of the pickup current is not the ion gyroperiod (as the conventional description might suggest) but rather the Alfvén wave travel time over the spatial scale of the inhomogeneity.

  12. Current Trends in Language Teaching

    ERIC Educational Resources Information Center

    Revue des Langues Vivantes, 1975

    1975-01-01

    Examines the effects of Chomsky's theories of linguistics and language acquisition on language teaching methodology, specifically on the use of the audio-lingual method. Current trends in methodology move in two basic directions: 1) towards relaxation of the tighter restrictions of the audio-lingual method, and 2) towards development of techniques…

  13. Current Physics Research. Part II.

    ERIC Educational Resources Information Center

    Schewe, Phillip F.

    1980-01-01

    Discussed are two current physics research areas. Solar cell efficiencies are discussed relating to present and future conversion efficiencies. Topics discussed in Astrophysics include the observation of astronomical bodies at different wavelengths, in terms of electromagnetic spectrum, tools of astronomy, compact stars, pulsars X-ray binaries,…

  14. On tridimensional rip current modeling

    NASA Astrophysics Data System (ADS)

    Marchesiello, Patrick; Benshila, Rachid; Almar, Rafael; Uchiyama, Yusuke; McWilliams, James C.; Shchepetkin, Alexander

    2015-12-01

    Do lateral shear instabilities of nearshore circulation account for a substantial part of Very Low-Frequency (VLF) variability? If yes, it would promote stirring and mixing of coastal waters and surf-shelf exchanges. Another question is whether tridimensional transient processes are important for instability generation. An innovative modeling system with tridimensional wave-current interactions was designed to investigate transient nearshore currents and interactions between nearshore and innershelf circulations. We present here some validation of rip current modeling for the Aquitanian coast of France, using in-situ and remote video sensing. We then proceed to show the benefits of 3D versus 2D (depth-mean flow) modeling of rip currents and their low-frequency variability. It appears that a large part of VLF motions is due to intrinsic variability of the tridimensional flow. 3D models may thus provide a valuable, only marginally more expensive alternative to conventional 2D approaches that miss the vertical flow structure and its nonlinear interaction with the depth-averaged flow.

  15. High critical current superconducting tapes

    DOEpatents

    Holesinger, Terry G.; Jia, Quanxi; Foltyn, Stephen R.

    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.

  16. The Current Conjuncture in Theory.

    ERIC Educational Resources Information Center

    Sprinker, Michael

    1989-01-01

    Describes the current debate in literary study between the humanist/historicist and the anti-humanist/anti-historicist perspectives. Examines the political dimensions of this debate, including its relationship to Marxist theory and deconstruction. Asserts that literary texts are productions of ideology and that literary study should inquire into…

  17. Power voltage current convertor using quasi complementary MOSFET current mirrors.

    PubMed

    Maclachlan, R A; Riviere, C N

    2011-10-13

    A voltage current convertor is described having a quasi complementary class AB architecture that is particularly suited to implementation using discrete power MOSFETs. High-voltage mirror designs are presented, enabling the construction of sources with kilovolt compliance range, tens of watts of output power and greater than 100 kHz bandwidth. GΩ output impedance and distortion below 1% can be obtained with no trimming or transistor matching. PMID:22312182

  18. Power voltage current convertor using quasi complementary MOSFET current mirrors

    PubMed Central

    MacLachlan, R. A.; Riviere, C. N.

    2011-01-01

    A voltage current convertor is described having a quasi complementary class AB architecture that is particularly suited to implementation using discrete power MOSFETs. High-voltage mirror designs are presented, enabling the construction of sources with kilovolt compliance range, tens of watts of output power and greater than 100 kHz bandwidth. GΩ output impedance and distortion below 1% can be obtained with no trimming or transistor matching. PMID:22312182

  19. Rotation of tokamak halo currents

    SciTech Connect

    Boozer, Allen H.

    2012-05-15

    During tokamak disruptions, halo currents, which can be tenths of the total plasma current, can flow at the plasma edge along the magnetic field lines that intercept the chamber walls. Non-axisymmetric halo currents are required to maintain force balance as the plasma kinks when the edge safety factor drops to about two in a vertical displacement event. The plasma quickly assumes a definite toroidal velocity v{sub a}(r) with respect to that of the magnetic kink, v{sub k}, where v{sub a}(r) is set by the radial electric field required for ambipolarity. The plasma velocity, v{sub pl}=v{sub a}+v{sub k}, near the edge is influenced by the interaction with neutrals and with the potential in the halo required for quasi-neutrality on open magnetic field lines, and the plasma velocity in the core is influenced by external error fields. When plasma effects dominate magnetic locking, the magnetic kink should rotate at a diamagnetic speed of either the edge or the core. If the magnetic field lines of the halo plasma intercept the wall at locations of very different electrical conductivity, the toroidal rotation of the halo currents can intermittently stall at wall locations of high conductivity. Such stalling is seen in experiments. The toroidal phase difference between the stalled halo currents and the kink, which is expected to rotate smoothly, must satisfy {delta}{phi}<{+-}{pi}/2. A concern cited by ITER engineers is that the time varying force of the rotating halo could substantially increase the disruption loads on in-vessel components.

  20. Current collection in a magnetoplasma

    NASA Technical Reports Server (NTRS)

    Laframboise, Jim G.; Sonmor, L. J.

    1990-01-01

    The authors present a survey of a very incomplete subject, current collection in a magnetoplasma. The best-developed and simplest theories for current collection are steady-state collisionless theories, and these must be understood before departures from them can be analyzed usefully. Thus, the authors begin with a review of them. The authors include some recent numerical results which indicate that steady-state collisionless Laplace-limit currents remain substantially below the Parker-Murphy (1967) canonical upper bound out to very large electrode potentials, and approach it as a limit only very slowly if at all. Attempts to correct this theory for space-charge effects lead to potential disturbances which extend to infinite distance along the electrode's magnetic shadow, unless collisional effects are also taken into account. However, even a small amount of relative plasma drift motion, such as that involved in a typical rocket experiment, can change this conclusion fundamentally. It is widely believed that time-averaged current collection may be increased by effects of plasma turbulence, and the authors review the available evidence for and against this contention. Steady-state collisionless particle dynamics predicts the existence of a toroidal region of trapped orbits which surrounds the electrode. Light emissions from this region have been photographed, indicating that collisional ionization may also occur there, and this, and/or scattering by collisions or possibly turbulent fluctuations in this region, may also increase current collection by the electrode. The authors also discuss effects on particle motions near the electrode, associated with breakdown of magnetic insulation in the region of large electric fields near it.

  1. Rotation of tokamak halo currents

    NASA Astrophysics Data System (ADS)

    Boozer, Allen H.

    2012-05-01

    During tokamak disruptions, halo currents, which can be tenths of the total plasma current, can flow at the plasma edge along the magnetic field lines that intercept the chamber walls. Non-axisymmetric halo currents are required to maintain force balance as the plasma kinks when the edge safety factor drops to about two in a vertical displacement event. The plasma quickly assumes a definite toroidal velocity va(r) with respect to that of the magnetic kink, vk, where va(r) is set by the radial electric field required for ambipolarity. The plasma velocity, vpl=va+vk, near the edge is influenced by the interaction with neutrals and with the potential in the halo required for quasi-neutrality on open magnetic field lines, and the plasma velocity in the core is influenced by external error fields. When plasma effects dominate magnetic locking, the magnetic kink should rotate at a diamagnetic speed of either the edge or the core. If the magnetic field lines of the halo plasma intercept the wall at locations of very different electrical conductivity, the toroidal rotation of the halo currents can intermittently stall at wall locations of high conductivity. Such stalling is seen in experiments. The toroidal phase difference between the stalled halo currents and the kink, which is expected to rotate smoothly, must satisfy δϕ <±π/2. A concern cited by ITER engineers is that the time varying force of the rotating halo could substantially increase the disruption loads on in-vessel components.

  2. The current-voltage relationship in auroral current sheets

    SciTech Connect

    Weimer, D.R. ); Gurnett, D.A.; Goertz, C.K. ); Menietti, J.D.; Burch, J.L. ); Sugiura, M. )

    1987-01-01

    The current-voltage relation within narrow auroral current sheets is examined through the use of high-resolution data from the high-altitude Dynamics Explorer 1 satellite. The north-south perpendicular electric field and the east-west magnetic field are shown for three cases in which there are large amplitude, oppositely directed paired electric fields which are confined to a region less than 20 km wide. The magnetic field variations are found to be proportional to the second integral of the high-altitude perpendicular electric field. It is shown that at the small-scale limit, this relationship between {Delta}B and E is consistent with a linear Ohm's law relationship between the current density and the parallel potential drop along the magnetic field line. This linear relationship had previously been verified for large-scale auroral formations greater than 20 km wide at the ionosphere. The evidence shown here extends the knowledge down to the scale size of discrete auroral arcs.

  3. Current responsive devices for synchronous generators

    DOEpatents

    Karlicek, Robert F.

    1983-01-01

    A device for detecting current imbalance between phases of a polyphase alternating current generator. A detector responds to the maximum peak current in the generator, and detecting means generates an output for each phase proportional to the peak current of each phase. Comparing means generates an output when the maximum peak current exceeds the phase peak current.

  4. Current responsive devices for synchronous generators

    DOEpatents

    Karlicek, R.F.

    1983-09-27

    A device for detecting current imbalance between phases of a polyphase alternating current generator. A detector responds to the maximum peak current in the generator, and detecting means generates an output for each phase proportional to the peak current of each phase. Comparing means generates an output when the maximum peak current exceeds the phase peak current. 11 figs.

  5. Current issues in atmospheric change

    NASA Technical Reports Server (NTRS)

    1987-01-01

    In response to questions about the effects of long-term, global-scale changes in the atmosphere raised in congressional hearings, a group of leading experts held a two-day workshop to survey the state of current knowledge about atmospheric changes and their implications. The review focuses on the sources, concentrations, and changes of those gases most directly linked to human activities, i.e., carbon dioxide, ozone, and the chlorofluorocarbons; the direct physical effects of rising concentrations of trace gases. The review discusses the uncertainties associated with the knowledge of current trends and possible future changes, including ozone trends and the Antarctic ozone hole, and the impacts of rising concentrations of trace gases.

  6. Hobetron current regulating switch tube

    SciTech Connect

    True, R.B.; Hansen, R.J.; Deb, D.N.; Good, G.R.; Reass, W.A.

    1999-07-01

    This paper describes a novel high power electron tube that can hold off voltages up to hundreds of kilovolts, and switch hundreds of amps of current. They call the divide the Hobertron since it utilizes a hollow electron beam. Unlike magnetron injection gun (MIG) switch tubes, it does not require a magnet. Further, it uses nonintercepting control laments, and a dispenser cathode for long life and reliability. Finally, it features a double walled Faraday cage collector for high power dissipation capability. Current is very tightly controlled against changes in voltage across the switch (it is an almost perfect pentode), thus this tube is ideally suited for direct series switching applications. In the paper, various Hobertron designs, and the computer codes and methods used to create them, will be described.

  7. Current Concept of Geometrical Accuracy

    NASA Astrophysics Data System (ADS)

    Görög, Augustín; Görögová, Ingrid

    2014-06-01

    Within the solving VEGA 1/0615/12 research project "Influence of 5-axis grinding parameters on the shank cutteŕs geometric accuracy", the research team will measure and evaluate geometrical accuracy of the produced parts. They will use the contemporary measurement technology (for example the optical 3D scanners). During the past few years, significant changes have occurred in the field of geometrical accuracy. The objective of this contribution is to analyse the current standards in the field of geometric tolerance. It is necessary to bring an overview of the basic concepts and definitions in the field. It will prevent the use of outdated and invalidated terms and definitions in the field. The knowledge presented in the contribution will provide the new perspective of the measurement that will be evaluated according to the current standards.

  8. Solid-state current transformer

    NASA Technical Reports Server (NTRS)

    Farnsworth, D. L. (Inventor)

    1976-01-01

    A signal transformation network which is uniquely characterized to exhibit a very low input impedance while maintaining a linear transfer characteristic when driven from a voltage source and when quiescently biased in the low microampere current range is described. In its simplest form, it consists of a tightly coupled two transistor network in which a common emitter input stage is interconnected directly with an emitter follower stage to provide virtually 100 percent negative feedback to the base input of the common emitter stage. Bias to the network is supplied via the common tie point of the common emitter stage collector terminal and the emitter follower base stage terminal by a regulated constant current source, and the output of the circuit is taken from the collector of the emitter follower stage.

  9. Current status of viroid taxonomy.

    PubMed

    Di Serio, F; Flores, R; Verhoeven, J Th J; Li, S-F; Pallás, V; Randles, J W; Sano, T; Vidalakis, G; Owens, R A

    2014-12-01

    Viroids are the smallest autonomous infectious nucleic acids known so far. With a small circular RNA genome of about 250-400 nt, which apparently does not code for any protein, viroids replicate and move systemically in host plants. Since the discovery of the first viroid almost forty-five years ago, many different viroids have been isolated, characterized and, frequently, identified as the causal agents of plant diseases. The first viroid classification scheme was proposed in the early 1990s and adopted by the International Committee on Taxonomy of Viruses (ICTV) a few years later. Here, the current viroid taxonomy scheme and the criteria for viroid species demarcation are discussed, highlighting the main taxonomic questions currently under consideration by the ICTV Viroid Study Group. The impact of correct taxonomic annotation of viroid sequence variants is also addressed, taking into consideration the increasing application of next-generation sequencing and bioinformatics for known and previously unrecognized viroids. PMID:25216773

  10. Current strategies in dentin remineralization.

    PubMed

    Hernández, Marcela; Cobb, Deborah; Swift, Edward J

    2014-01-01

    Partial caries removal procedures are used clinically in an attempt to conserve tooth structure and prevent pulp damage. Within this approach, the caries-infected dentin is removed, and the partially demineralized caries-affected dentin is preserved and sealed with materials that enhance remineralization. Fluoride-releasing glass ionomers have been commonly used for this purpose. Recent studies have shown potential for other cements and bioactive adhesive materials to promote dentin repair through various strategies. These strategies include ion releasing of Ca-P and the guided tissue remineralization or biomimetic remineralization of dentin. The latter is potentially useful in the remineralization of the demineralized acid-etched dentin that is incompletely infiltrated by adhesives in dentin bonding. The purpose of this Critical Appraisal is to provide the clinician with a summary of current literature that clarifies understanding of the process of dentin remineralization and to describe current strategies in this area. PMID:24612484

  11. Current concepts of severe asthma.

    PubMed

    Ray, Anuradha; Raundhal, Mahesh; Oriss, Timothy B; Ray, Prabir; Wenzel, Sally E

    2016-07-01

    The term asthma encompasses a disease spectrum with mild to very severe disease phenotypes whose traditional common characteristic is reversible airflow limitation. Unlike milder disease, severe asthma is poorly controlled by the current standard of care. Ongoing studies using advanced molecular and immunological tools along with improved clinical classification show that severe asthma does not identify a specific patient phenotype, but rather includes patients with constant medical needs, whose pathobiologic and clinical characteristics vary widely. Accordingly, in recent clinical trials, therapies guided by specific patient characteristics have had better outcomes than previous therapies directed to any subject with a diagnosis of severe asthma. However, there are still significant gaps in our understanding of the full scope of this disease that hinder the development of effective treatments for all severe asthmatics. In this Review, we discuss our current state of knowledge regarding severe asthma, highlighting different molecular and immunological pathways that can be targeted for future therapeutic development. PMID:27367183

  12. Current status of transarterial radioembolization

    PubMed Central

    Mahnken, Andreas H

    2016-01-01

    Unresectable primary and secondary liver malignancies present a major problem in the treatment of solid tumors. Transarterial radioembolization (TARE) is an increasingly used technique for treating various types of malignant liver tumors. This approach is appealing, as the mechanism of action is independent from other loco-regional treatments and potentially complementary to systemic therapies. There are two commercially available products in use for TARE: 90Y-resin and 90Y-glass microspheres. Currently available data indicates TARE so be safe and effective in hepatocellular carcinoma (HCC) and metastatic liver disease. In HCC the results compare well with chemoembolization, while the role of TARE in combination with kinase inhibitors has yet to be established. Current data on TARE in metastatic liver disease is promising, but there is a strong need for prospective randomized trials comparing TARE and modern chemotherapeutic regimen to support the growing role of TARE in metastatic liver disease. PMID:27247711

  13. Leakage currents in SOI MOSFETS

    SciTech Connect

    Annamala, N.K.; Biwer, M.C.

    1988-12-01

    Total dose response of both NMOS and PMOS FETs fabricated on SOI substrates was studied. Two types of back-channel leakage currents were identified. A back-channel leakage due to MOSFET action uses the substrate bias as the gate bias. The other component is due to soft reverse characteristics of the body-drain junction. The back-channel leakage due to MOSFET action varies with the substrate bias and hence varies with irradiation due to threshold voltage shift. The soft reverse characteristics are a function of drain-body voltage and hence vary with substrate bias and irradiation. I-V characteristics and subthreshold currents of both front and back channels as a function of total dose were obtained.

  14. Current status of transarterial radioembolization.

    PubMed

    Mahnken, Andreas H

    2016-05-28

    Unresectable primary and secondary liver malignancies present a major problem in the treatment of solid tumors. Transarterial radioembolization (TARE) is an increasingly used technique for treating various types of malignant liver tumors. This approach is appealing, as the mechanism of action is independent from other loco-regional treatments and potentially complementary to systemic therapies. There are two commercially available products in use for TARE: (90)Y-resin and (90)Y-glass microspheres. Currently available data indicates TARE so be safe and effective in hepatocellular carcinoma (HCC) and metastatic liver disease. In HCC the results compare well with chemoembolization, while the role of TARE in combination with kinase inhibitors has yet to be established. Current data on TARE in metastatic liver disease is promising, but there is a strong need for prospective randomized trials comparing TARE and modern chemotherapeutic regimen to support the growing role of TARE in metastatic liver disease. PMID:27247711

  15. Remote field eddy current inspection

    SciTech Connect

    Atherton, D.L.

    1995-11-01

    The Remote Field Eddy Current (RFEC) technique uses an internal probe to inspect conducting tubes nondestructively. A coaxial solenoidal exciter, energized with low frequency AC, and detector coils near the inside of the pipe wall are separated by about two pipe diameters to obtain through wall transmission and equal sensitivity to defects on the outside or inside of the pipe wall. Calculation methods are outlined and the voltage plane polar plot signal representation for defect measurement is described. Slit defect interactions in ferromagnetic and non-ferromagnetic tubes are discussed. Defect-induced anomalous fields are interpreted in terms of anomalous source eddy current and missing magnetization defect models. The use of computer animations to represent the time variations of high resolution field measurements and calculations is described.

  16. Submesoscale currents in the ocean

    PubMed Central

    2016-01-01

    This article is a perspective on the recently discovered realm of submesoscale currents in the ocean. They are intermediate-scale flow structures in the form of density fronts and filaments, topographic wakes and persistent coherent vortices at the surface and throughout the interior. They are created from mesoscale eddies and strong currents, and they provide a dynamical conduit for energy transfer towards microscale dissipation and diapycnal mixing. Consideration is given to their generation mechanisms, instabilities, life cycles, disruption of approximately diagnostic force balance (e.g. geostrophy), turbulent cascades, internal-wave interactions, and transport and dispersion of materials. At a fundamental level, more questions remain than answers, implicating a programme for further research. PMID:27279778

  17. Current trends in oxysterol research.

    PubMed

    Griffiths, William J; Abdel-Khalik, Jonas; Hearn, Thomas; Yutuc, Eylan; Morgan, Alwena H; Wang, Yuqin

    2016-04-15

    In this short review we provide a synopsis of recent developments in oxysterol research highlighting topics of current interest to the community. These include the involvement of oxysterols in neuronal development and survival, their participation in the immune system, particularly with respect to bacterial and viral infection and to Th17-cell development, and the role of oxysterols in breast cancer. We also discuss the value of oxysterol analysis in the diagnosis of disease. PMID:27068984

  18. Current trends in oxysterol research

    PubMed Central

    Griffiths, William J.; Abdel-Khalik, Jonas; Hearn, Thomas; Yutuc, Eylan; Morgan, Alwena H.; Wang, Yuqin

    2016-01-01

    In this short review we provide a synopsis of recent developments in oxysterol research highlighting topics of current interest to the community. These include the involvement of oxysterols in neuronal development and survival, their participation in the immune system, particularly with respect to bacterial and viral infection and to Th17-cell development, and the role of oxysterols in breast cancer. We also discuss the value of oxysterol analysis in the diagnosis of disease. PMID:27068984

  19. Current Directions in Mediation Analysis

    PubMed Central

    MacKinnon, David P.; Fairchild, Amanda J.

    2010-01-01

    Mediating variables continue to play an important role in psychological theory and research. A mediating variable transmits the effect of an antecedent variable on to a dependent variable, thereby providing more detailed understanding of relations among variables. Methods to assess mediation have been an active area of research for the last two decades. This paper describes the current state of methods to investigate mediating variables. PMID:20157637

  20. High PRF high current switch

    DOEpatents

    Moran, Stuart L.; Hutcherson, R. Kenneth

    1990-03-27

    A triggerable, high voltage, high current, spark gap switch for use in pu power systems. The device comprises a pair of electrodes in a high pressure hydrogen environment that is triggered by introducing an arc between one electrode and a trigger pin. Unusually high repetition rates may be obtained by undervolting the switch, i.e., operating the trigger at voltages much below the self-breakdown voltage of the device.

  1. Current Epidemiology of Genitourinary Trauma

    PubMed Central

    McGeady, James B.; Breyer, Benjamin N.

    2013-01-01

    Synopsis This article reviews recent publications evaluating the current epidemiology of urologic trauma. It begins by providing a brief explanation of databases that have been recently used to study this patient population, then proceeds to discuss each genitourinary organ individually, discussing the most relevant and up to date information published for each one. The conclusion of the article briefly discusses possible future research and development areas pertaining to the topic. PMID:23905930

  2. For current viewing resistor loads

    DOEpatents

    Lyons, Gregory R.; Hass, Jay B.

    2011-04-19

    The invention comprises a terminal unit for a flat cable comprising a BNC-PCB connector having a pin for electrically contacting one or more conducting elements of a flat cable, and a current viewing resistor having an opening through which the pin extends and having a resistor face that abuts a connector face of the BNC-PCB connector, wherein the device is a terminal unit for the flat cable.

  3. Cervical arterial dissection: current concepts .

    PubMed

    Menon, Ranjith K; Norris, John W

    2008-10-01

    The increasing use and safety of noninvasive imaging in recent years has revealed the surprising frequency of dissection of the carotid and vertebral arteries (cervical arterial dissection [CAD]) as a cause of ischemic and hemorrhagic stroke. This review is an overview of current concepts and practice of patients with CAD, but our ideas are constantly evolving with new discoveries from neurovascular imaging and medical and surgical management in this area. PMID:18990128

  4. Supply Current Diagnosis in VLSI

    NASA Technical Reports Server (NTRS)

    Frenzel, J. F.; Marinos, P. N.

    1990-01-01

    This paper presents a technique based upon the power supply current signature (cd) which allows for the testing of mixed-signal systems, in situ. Through experiments with a microprocessor, the cd is shown to contain important information concerning the operational status of the system which may be easily extracted using approaches based on statistical signal detection theory. The fault-detection performance of these techniques is compared to that achieved through auto-regressive modeling of the cd.

  5. [Current therapy of multiple sclerosis].

    PubMed

    Antonio García Merino, J

    2014-12-01

    Since the introduction of interferon beta 1 b for the treatment of multiple sclerosis, there has been a progressive increase in the number of drugs available for this disease. Currently, 11 drugs have been approved in Spain, and their indications depend on specific clinical characteristics. The present article reviews these indications and also discusses other medications without official approval that have also been used in multiple sclerosis. PMID:25732945

  6. Current-Induced Membrane Discharge

    NASA Astrophysics Data System (ADS)

    Andersen, M. B.; van Soestbergen, M.; Mani, A.; Bruus, H.; Biesheuvel, P. M.; Bazant, M. Z.

    2012-09-01

    Possible mechanisms for overlimiting current (OLC) through aqueous ion-exchange membranes (exceeding diffusion limitation) have been debated for half a century. Flows consistent with electro-osmotic instability have recently been observed in microfluidic experiments, but the existing theory neglects chemical effects and remains to be quantitatively tested. Here, we show that charge regulation and water self-ionization can lead to OLC by “current-induced membrane discharge” (CIMD), even in the absence of fluid flow, in ion-exchange membranes much thicker than the local Debye screening length. Salt depletion leads to a large electric field resulting in a local pH shift within the membrane with the effect that the membrane discharges and loses its ion selectivity. Since salt co-ions, H+ ions, and OH- ions contribute to OLC, CIMD interferes with electrodialysis (salt counterion removal) but could be exploited for current-assisted ion exchange and pH control. CIMD also suppresses the extended space charge that leads to electro-osmotic instability, so it should be reconsidered in both models and experiments on OLC.

  7. Current-induced membrane discharge.

    PubMed

    Andersen, M B; van Soestbergen, M; Mani, A; Bruus, H; Biesheuvel, P M; Bazant, M Z

    2012-09-01

    Possible mechanisms for overlimiting current (OLC) through aqueous ion-exchange membranes (exceeding diffusion limitation) have been debated for half a century. Flows consistent with electro-osmotic instability have recently been observed in microfluidic experiments, but the existing theory neglects chemical effects and remains to be quantitatively tested. Here, we show that charge regulation and water self-ionization can lead to OLC by "current-induced membrane discharge" (CIMD), even in the absence of fluid flow, in ion-exchange membranes much thicker than the local Debye screening length. Salt depletion leads to a large electric field resulting in a local pH shift within the membrane with the effect that the membrane discharges and loses its ion selectivity. Since salt co-ions, H(+) ions, and OH(-) ions contribute to OLC, CIMD interferes with electrodialysis (salt counterion removal) but could be exploited for current-assisted ion exchange and pH control. CIMD also suppresses the extended space charge that leads to electro-osmotic instability, so it should be reconsidered in both models and experiments on OLC. PMID:23005334

  8. The Arctic Circumpolar Boundary Current

    NASA Astrophysics Data System (ADS)

    Aksenov, Yevgeny; Ivanov, Vladimir V.; Nurser, A. J. George; Bacon, Sheldon; Polyakov, Igor V.; Coward, Andrew C.; Naveira-Garabato, Alberto C.; Beszczynska-Moeller, Agnieszka

    2011-09-01

    We present high-resolution simulations and observational data as evidence of a fast current flowing along the shelf break of the Siberian and Alaskan shelves in the Arctic Ocean. Thus far, the Arctic Circumpolar Boundary Current (ACBC) has been seen as comprising two branches: the Fram Strait and Barents Sea Branches (FSB and BSB, respectively). Here we describe a new third branch, the Arctic Shelf Break Branch (ASBB). We show that the forcing mechanism for the ASBB is a combination of buoyancy loss and non-local wind, creating high pressure upstream in the Barents Sea. The potential vorticity influx through the St. Anna Trough dictates the cyclonic direction of flow of the ASBB, which is the most energetic large-scale circulation structure in the Arctic Ocean. It plays a substantial role in transporting Arctic halocline waters and exhibits a robust seasonal cycle with a summer minimum and winter maximum. The simulations show the continuity of the FSB all the way around the Arctic shelves and the uninterrupted ASBB between the St. Anna Trough and the western Fram Strait. The BSB flows continuously along the Siberian shelf as far as the Chukchi Plateau, where it partly diverges from the continental slope into the ocean interior. The Alaskan Shelf break Current (ASC) is the analog of the ASBB in the Canadian Arctic. The ASC is forced by the local winds and high upstream pressure in Bering Strait, caused by the drop in sea surface height between the Pacific and Arctic Oceans.

  9. Reconnection in thin current sheets

    NASA Astrophysics Data System (ADS)

    Tenerani, Anna; Velli, Marco; Pucci, Fulvia; Rappazzo, A. F.

    2016-05-01

    It has been widely believed that reconnection is the underlying mechanism of many explosive processes observed both in nature and laboratory, but the question of reconnection speed and initial trigger have remained mysterious. How is fast magnetic energy release triggered in high Lundquist (S) and Reynolds (R) number plasmas?It has been shown that a tearing mode instability can grow on an ideal timescale, i.e., independent from the the Lundquist number, once the current sheet thickness becomes thin enough, or rather the inverse aspect ratio a/L reaches a scale a/L~S-1/3. As such, the latter provides a natural, critical threshold for current sheets that can be formed in nature before they disrupt in a few Alfvén time units. Here we discuss the transition to fast reconnection extended to simple viscous and kinetic models and we propose a possible scenario for the transition to explosive reconnection in high-Lundquist number plasmas, that we support with fully nonlinear numerical MHD simulations of a collapsing current sheet.

  10. Female pattern alopecia: current perspectives

    PubMed Central

    Levy, Lauren L; Emer, Jason J

    2013-01-01

    Hair loss is a commonly encountered problem in clinical practice, with men presenting with a distinctive pattern involving hairline recession and vertex balding (Norwood-Hamilton classification) and women exhibiting diffuse hair thinning over the crown (increased part width) and sparing of the frontal hairline (Ludwig classification). Female pattern hair loss has a strikingly overwhelming psychological effect; thus, successful treatments are necessary. Difficulty lies in successful treatment interventions, as only two medications – minoxidil and finasteride – are approved for the treatment of androgenetic alopecia, and these medications offer mediocre results, lack of a permanent cure, and potential complications. Hair transplantation is the only current successful permanent option, and it requires surgical procedures. Several other medical options, such as antiandrogens (eg, spironolactone, oral contraceptives, cyproterone, flutamide, dutasteride), prostaglandin analogs (eg, bimatoprost, latanoprost), and ketoconazole are reported to be beneficial. Laser and light therapies have also become popular despite the lack of a profound benefit. Management of expectations is crucial, and the aim of therapy, given the current therapeutic options, is to slow or stop disease progression with contentment despite patient expectations of permanent hair regrowth. This article reviews current perspectives on therapeutic options for female pattern hair loss. PMID:24039457

  11. Female pattern alopecia: current perspectives.

    PubMed

    Levy, Lauren L; Emer, Jason J

    2013-01-01

    Hair loss is a commonly encountered problem in clinical practice, with men presenting with a distinctive pattern involving hairline recession and vertex balding (Norwood-Hamilton classification) and women exhibiting diffuse hair thinning over the crown (increased part width) and sparing of the frontal hairline (Ludwig classification). Female pattern hair loss has a strikingly overwhelming psychological effect; thus, successful treatments are necessary. Difficulty lies in successful treatment interventions, as only two medications - minoxidil and finasteride - are approved for the treatment of androgenetic alopecia, and these medications offer mediocre results, lack of a permanent cure, and potential complications. Hair transplantation is the only current successful permanent option, and it requires surgical procedures. Several other medical options, such as antiandrogens (eg, spironolactone, oral contraceptives, cyproterone, flutamide, dutasteride), prostaglandin analogs (eg, bimatoprost, latanoprost), and ketoconazole are reported to be beneficial. Laser and light therapies have also become popular despite the lack of a profound benefit. Management of expectations is crucial, and the aim of therapy, given the current therapeutic options, is to slow or stop disease progression with contentment despite patient expectations of permanent hair regrowth. This article reviews current perspectives on therapeutic options for female pattern hair loss. PMID:24039457

  12. The current management of cholangiocarcinoma: A comparison of current guidelines.

    PubMed

    Cai, Yulong; Cheng, Nansheng; Ye, Hui; Li, Fuyu; Song, Peipei; Tang, Wei

    2016-05-23

    Cholangiocarcinoma (CC) accounts for about 3% of all gastrointestinal tumors and is the second most common primary liver tumor. Quality guidelines on CC are needed to guide hepatobiliary surgeons. Here, current guidelines on CC were reviewed to provide useful information and suggestions to help institutes and organizations all around the world to draft better guidelines on CC. Literature databases were electronically searched to identify guidelines or consensus statements regarding CC published from 2002-2016. Nine guidelines were included in this review. Comparison of the current guidelines revealed several inconsistencies. Signs of conflicting views indicated a lack of high level evidence. More studies need to be conducted in areas of contention to help update the guidelines. Organizations and medical societies need to be encouraged to use standard evaluation measures, to restrict tumors to CC or iCC, pCC, or dCC specifically, to give recommendations in accordance with the equipment that is available for diagnosis and treatment in different counties, and to use an appropriate and consistent structure when establishing and drafting guidelines for CC. PMID:27026485

  13. Magnetorotational instability, current relaxation, and current-vortex sheet

    SciTech Connect

    Silveira, F. E. M.; Galvão, R. M. O.

    2013-08-15

    The conjugate effect of current relaxation and of current-vortex sheet formation on the magnetorotational instability is explored in a conducting fluid. It is found that the relative amplification of the magnetic viscosity from marginal stability to the instability determined by the maximum growth rate is around 924% when resistive effects dominate, while the corresponding quantity is around 220% in the ideal limit. This shows that the conjugate influence is much more efficient to amplify the magnetic viscosity than just the effect due to the standard magnetic tension. It is also found that the magnitude of the magnetic viscosity is effectively enhanced by the conjugate influence. The results presented here may contribute to the understanding of the various processes that play a significant role in the mechanism of anomalous viscosity observed in Keplerian disks. It is argued that the new effect shall be relevant in thin accretion disks. It is also mentioned that the proposed formulation may be of interest for some theories of magnetic reconnection. Possible extensions of this work are suggested.

  14. Current Topics in Epilepsy Surgery.

    PubMed

    Usui, Naotaka

    2016-05-15

    This article reviews the current topics in the field of epilepsy surgery. Each type of epilepsy is associated with a different set of questions and goals. In mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis (HS), postoperative seizure outcome is satisfactory. A recent meta-analysis revealed superior seizure outcome after anterior temporal lobectomy compared with selective amygdalohippocampectomy; in terms of cognitive outcome; however, amygdalohippocampectomy may be beneficial. In temporal lobe epilepsy with normal magnetic resonance imaging (MRI), postoperative seizure outcome is not as favorable as it is in MTLE with HS; further improvement of seizure outcome in these cases is necessary. Focal cortical dysplasia is the most common substrate in intractable neocortical epilepsy, especially in children, as well as in MRI-invisible neocortical epilepsy. Postoperative seizure-free outcome is approximately 60-70%; further diagnostic and therapeutic improvement is required. Regarding diagnostic methodology, an important topic currently under discussion is wideband electroencephalogram (EEG) analysis. Although high-frequency oscillations and ictal direct current shifts are considered important markers of epileptogenic zones, the clinical significance of these findings should be clarified further. Regarding alternatives to surgery, neuromodulation therapy can be an option for patients who are not amenable to resective surgery. In addition to vagus nerve stimulation, intracranial stimulation such as responsive neurostimulation or anterior thalamic stimulation is reported to have a modest seizure suppression effect. Postoperative management such as rehabilitation and antiepileptic drug (AED) management is important. It has been reported that postoperative rehabilitation improves postoperative employment status. Pre- and post-operative comprehensive care is mandatory for postoperative improvement of quality of life. PMID:26984452

  15. Internet gaming addiction: current perspectives.

    PubMed

    Kuss, Daria J

    2013-01-01

    In the 2000s, online games became popular, while studies of Internet gaming addiction emerged, outlining the negative consequences of excessive gaming, its prevalence, and associated risk factors. The establishment of specialized treatment centers in South-East Asia, the US, and Europe reflects the growing need for professional help. It is argued that only by understanding the appeal of Internet gaming, its context, and neurobiologic correlates can the phenomenon of Internet gaming addiction be understood comprehensively. The aim of this review is to provide an insight into current perspectives on Internet gaming addiction using a holistic approach, taking into consideration the mass appeal of online games, the context of Internet gaming addiction, and associated neuroimaging findings, as well as the current diagnostic framework adopted by the American Psychiatric Association. The cited research indicates that the individual's context is a significant factor that marks the dividing line between excessive gaming and gaming addiction, and the game context can gain particular importance for players, depending on their life situation and gaming preferences. Moreover, the cultural context is significant because it embeds the gamer in a community with shared beliefs and practices, endowing their gaming with particular meaning. The cited neuroimaging studies indicate that Internet gaming addiction shares similarities with other addictions, including substance dependence, at the molecular, neurocircuitry, and behavioral levels. The findings provide support for the current perspective of understanding Internet gaming addiction from a disease framework. The benefits of an Internet gaming addiction diagnosis include reliability across research, destigmatization of individuals, development of efficacious treatments, and the creation of an incentive for public health care and insurance providers. The holistic approach adopted here not only highlights empirical research that

  16. Internet gaming addiction: current perspectives

    PubMed Central

    Kuss, Daria J

    2013-01-01

    In the 2000s, online games became popular, while studies of Internet gaming addiction emerged, outlining the negative consequences of excessive gaming, its prevalence, and associated risk factors. The establishment of specialized treatment centers in South-East Asia, the US, and Europe reflects the growing need for professional help. It is argued that only by understanding the appeal of Internet gaming, its context, and neurobiologic correlates can the phenomenon of Internet gaming addiction be understood comprehensively. The aim of this review is to provide an insight into current perspectives on Internet gaming addiction using a holistic approach, taking into consideration the mass appeal of online games, the context of Internet gaming addiction, and associated neuroimaging findings, as well as the current diagnostic framework adopted by the American Psychiatric Association. The cited research indicates that the individual’s context is a significant factor that marks the dividing line between excessive gaming and gaming addiction, and the game context can gain particular importance for players, depending on their life situation and gaming preferences. Moreover, the cultural context is significant because it embeds the gamer in a community with shared beliefs and practices, endowing their gaming with particular meaning. The cited neuroimaging studies indicate that Internet gaming addiction shares similarities with other addictions, including substance dependence, at the molecular, neurocircuitry, and behavioral levels. The findings provide support for the current perspective of understanding Internet gaming addiction from a disease framework. The benefits of an Internet gaming addiction diagnosis include reliability across research, destigmatization of individuals, development of efficacious treatments, and the creation of an incentive for public health care and insurance providers. The holistic approach adopted here not only highlights empirical research that

  17. Current Topics in Epilepsy Surgery

    PubMed Central

    USUI, Naotaka

    2016-01-01

    This article reviews the current topics in the field of epilepsy surgery. Each type of epilepsy is associated with a different set of questions and goals. In mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis (HS), postoperative seizure outcome is satisfactory. A recent meta-analysis revealed superior seizure outcome after anterior temporal lobectomy compared with selective amygdalohippocampectomy; in terms of cognitive outcome; however, amygdalohippocampectomy may be beneficial. In temporal lobe epilepsy with normal magnetic resonance imaging (MRI), postoperative seizure outcome is not as favorable as it is in MTLE with HS; further improvement of seizure outcome in these cases is necessary. Focal cortical dysplasia is the most common substrate in intractable neocortical epilepsy, especially in children, as well as in MRI-invisible neocortical epilepsy. Postoperative seizure-free outcome is approximately 60–70%; further diagnostic and therapeutic improvement is required. Regarding diagnostic methodology, an important topic currently under discussion is wideband electroencephalogram (EEG) analysis. Although high-frequency oscillations and ictal direct current shifts are considered important markers of epileptogenic zones, the clinical significance of these findings should be clarified further. Regarding alternatives to surgery, neuromodulation therapy can be an option for patients who are not amenable to resective surgery. In addition to vagus nerve stimulation, intracranial stimulation such as responsive neurostimulation or anterior thalamic stimulation is reported to have a modest seizure suppression effect. Postoperative management such as rehabilitation and antiepileptic drug (AED) management is important. It has been reported that postoperative rehabilitation improves postoperative employment status. Pre- and post-operative comprehensive care is mandatory for postoperative improvement of quality of life. PMID:26984452

  18. Displacement current and surface flashover

    NASA Astrophysics Data System (ADS)

    Harris, J. R.; Caporaso, G. J.; Blackfield, D.; Chen, Y.-J.

    2007-09-01

    High-voltage vacuum insulator failure is generally due to surface flashover rather than insulator bulk breakdown. Vacuum surface flashover is widely believed to be initiated by a secondary electron emission avalanche along the vacuum-insulator interface. This process requires a physical mechanism to cause secondary electrons emitted from the insulator surface to return to that surface. Here, it is shown that when an insulator is subjected to a fast high-voltage pulse, the magnetic field due to displacement current through the insulator can provide this mechanism. This indicates the importance of the voltage pulse shape, especially the rise time, in the flashover initiation process.

  19. Remote sensing of ocean currents

    NASA Technical Reports Server (NTRS)

    Maul, G. A. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Monthly field experiments in support of the NOAA investigation of ocean color boundary determination using ERTS-1 data have been conducted since June 1972. The boundary between coastal waters and the Loop Current has been detected by ERTS-1 as a result of sea state changes as well as color differences. Ocean information is contained in all 24 channels of the Bendix MSS flown on the C-130 in June 1972; this includes UV, visible, reflected IR, and emitted IR. Computer enhancement of MSS data is revealing many features not shown in the NDPF product.

  20. Current status of NGL masks

    NASA Astrophysics Data System (ADS)

    Walker, David M.

    2000-07-01

    The manufacture of Next Generation Lithography reticles presents many challenges. Extremely small critical dimension and image placement error budgets; novel substrates including membranes and multi-layer reflective coatings; and inspection, detection and repair of subresolution defects will force revolutionary change in the infrastructure of mask technology. This paper surveys current NGL mask designs, structures, materials and manufacturing capabilities. Results from mask fabrication, physical modeling, error budget analysis and extensive experience in building X-Ray membrane masks are presented to develop process learning plans to meet future product specifications.

  1. Xerostomia: current streams of investigation.

    PubMed

    Quock, Ryan L

    2016-07-01

    Xerostomia is the subjective feeling of dry mouth, and it is often related to salivary hypofunction. Besides medication-related salivary hypofunction, Sjögren syndrome and head-and-neck radiation are two common etiologies that have garnered considerable attention. Approaches to treating and/or preventing salivary hypofunction in patients with these conditions will likely incorporate gene therapy, stem cell therapy, and tissue engineering. Advances in these disciplines are central to current research in the cure for xerostomia and will be key to eventual treatment. PMID:27189896

  2. Current Perspectives on Gastric Cancer.

    PubMed

    Marqués-Lespier, Juan M; González-Pons, María; Cruz-Correa, Marcia

    2016-09-01

    Gastric cancer (GC) is third leading cause of cancer-related death. Only 28.3% of new GC cases survive more than 5 years. Although incidence has declined in the United States, an increase is estimated for 2016. Risk factors include sex (risk is higher in men), Helicobacter pylori infection, heredity, and lifestyle. GC is usually diagnosed between the ages of 60-80 years. Prognosis of GC is largely dependent on the tumor stage at diagnosis and classification as intestinal or diffuse type; diffuse-type GC has worse prognosis. Chemoprevention has been shown to decrease risk, but is currently not used clinically. PMID:27546840

  3. Transient eddy current flow metering

    NASA Astrophysics Data System (ADS)

    Forbriger, J.; Stefani, F.

    2015-10-01

    Measuring local velocities or entire flow rates in liquid metals or semiconductor melts is a notorious problem in many industrial applications, including metal casting and silicon crystal growth. We present a new variant of an old technique which relies on the continuous tracking of a flow-advected transient eddy current that is induced by a pulsed external magnetic field. This calibration-free method is validated by applying it to the velocity of a spinning disk made of aluminum. First tests at a rig with a flow of liquid GaInSn are also presented.

  4. [Current description of multiple sclerosis].

    PubMed

    Río, Jordi; Montalbán, Xavier

    2014-12-01

    Multiple sclerosis is a multifocal demyelinating disease leading to progressive neurodegeneration caused by an autoimmune response in genetically predisposed individuals. In the last few years, the knowledge and management of this disease has been revolutionized by a series of findings. The present article reviews pathological features of the disease, in which cortical involvement is increasingly implicated, and aspects related to novel pathogenic mechanisms, such as the role of the microbiota in the genesis of multiple sclerosis, as well as recent contributions from the fields of epidemiology and genetics. Also reviewed are the latest diagnostic criteria, which currently allow a much earlier diagnosis, with clear therapeutic implications. PMID:25732942

  5. Current management of hepatocellular carcinoma

    PubMed Central

    Tabrizian, Parissa; Roayaie, Sasan; Schwartz, Myron E

    2014-01-01

    Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and leading cause of death among patients with cirrhosis. Treatment guidelines are based according to the Barcelona Clinic Liver Cancer staging system. The choice among therapeutic options that include liver resection, liver transplantation, locoregional, and systemic treatments must be individualized for each patient. The aim of this paper is to review the outcomes that can be achieved in the treatment of HCC with the heterogeneous therapeutic options currently available in clinical practice. PMID:25132740

  6. Nerve lesioning with direct current

    NASA Astrophysics Data System (ADS)

    Ravid, E. Natalie; Shi Gan, Liu; Todd, Kathryn; Prochazka, Arthur

    2011-02-01

    Spastic hypertonus (muscle over-activity due to exaggerated stretch reflexes) often develops in people with stroke, cerebral palsy, multiple sclerosis and spinal cord injury. Lesioning of nerves, e.g. with phenol or botulinum toxin is widely performed to reduce spastic hypertonus. We have explored the use of direct electrical current (DC) to lesion peripheral nerves. In a series of animal experiments, DC reduced muscle force by controlled amounts and the reduction could last several months. We conclude that in some cases controlled DC lesioning may provide an effective alternative to the less controllable molecular treatments available today.

  7. Ultrasound modulates ion channel currents.

    PubMed

    Kubanek, Jan; Shi, Jingyi; Marsh, Jon; Chen, Di; Deng, Cheri; Cui, Jianmin

    2016-01-01

    Transcranial focused ultrasound (US) has been demonstrated to stimulate neurons in animals and humans, but the mechanism of this effect is unknown. It has been hypothesized that US, a mechanical stimulus, may mediate cellular discharge by activating mechanosensitive ion channels embedded within cellular membranes. To test this hypothesis, we expressed potassium and sodium mechanosensitive ion channels (channels of the two-pore-domain potassium family (K2P) including TREK-1, TREK-2, TRAAK; NaV1.5) in the Xenopus oocyte system. Focused US (10 MHz, 0.3-4.9 W/cm(2)) modulated the currents flowing through the ion channels on average by up to 23%, depending on channel and stimulus intensity. The effects were reversible upon repeated stimulation and were abolished when a channel blocker (ranolazine to block NaV1.5, BaCl2 to block K2P channels) was applied to the solution. These data reveal at the single cell level that focused US modulates the activity of specific ion channels to mediate transmembrane currents. These findings open doors to investigations of the effects of  US on ion channels expressed in neurons, retinal cells, or cardiac cells, which may lead to important medical applications. The findings may also pave the way to the development of sonogenetics: a non-invasive, US-based analogue of optogenetics. PMID:27112990

  8. Sinoprobe Datacenter Development: Current Status

    NASA Astrophysics Data System (ADS)

    Guan, Y.; Dong, S.; Chen, Z.; Chen, G.; Cheng, M.

    2011-12-01

    The project of the Sinoprobe datacenter development is to build new IT infrastructures needed to store, visualize and manage all the data acquired by SinoProbe program.The SinoProbe data center is designed using service-oriented architecture (SOA) principles. More specifically, service component architecture (SCA) is used to implement sinoprobe data services. It also uses various advanced technologies such as Java/JEE for the platform, PostgresSQL/PostGIS for the data storage, ApacheDS for LDAP, CoachDB for the medadata storage, GeoServer for the GIS services, ExtJs and OpenLayer for the Ajax framework, and Apache Shiro for the security framework. Through the integration and development of various technologies used, the major services of the datacenter system are implemented including the security infrastructure services (user authentication and authorization), metadata services, data warehouse stores, data services, GIS services, and web portal. There are also visualization components including the development of a virtual globe to replace the currently used Google Earth. This poster presents the current status of the SinoProbe data center development, and the detailed discussion of the system.

  9. Current Practice of Duodenoscope Reprocessing.

    PubMed

    Kim, Stephen; Muthusamy, V Raman

    2016-10-01

    Numerous outbreaks of duodenoscope-associated transmission of multi-drug resistant bacteria have recently been reported. Unlike prior episodes of endoscope-transmitted infections, the latest outbreaks have occurred despite strict adherence to duodenoscope reprocessing guidelines. The current standard for all flexible endoscope reprocessing includes pre-cleaning, leak testing, an additional manual cleaning step, and high-level disinfection. When these steps are strictly followed, the risk of infection transmission during endoscopy is exceedingly rare. However, due to its complex design, the duodenoscope may not be able to be adequately disinfected using the current reprocessing standards. Supplemental measures to enhance scope reprocessing have subsequently been recommended to reduce the infection risk in patients undergoing endoscopic retrograde cholangiopancreatography. These methods are likely short-term solutions that have yet to be validated regarded their effectiveness. Additional approaches to monitor the quality of duodenoscope reprocessing may also be useful. Ultimately, a definitive, yet logistically feasible, method of duodenoscope reprocessing is required to ensure the safety of our patients. PMID:27595583

  10. The magnetohydrodynamics of current sheets

    NASA Technical Reports Server (NTRS)

    Priest, E. R.

    1985-01-01

    Examples of current sheets are summarized and their formation is described. A universal phenomenon in cosmic plasmas is the creation of sheets off intense current near X-type neutral points (where the magnetic field vanishes). These sheets are important as sites where the magnetic-field energy is converted efficiently into heat and bulk kinetic energy and where particles can be accelerated to high energies. Examples include disruptions in laboratory tokamaks, substorms in the earth's magnetosphere, and flares on the sun. The basic behavior of a one-dimensional sheet is presented, together with an account of the linear tearing-mode instability that can cause the field lines in such a sheet to reconnect. Such reconnection may develop in different ways: it may arise from a spontaneous instability or it may be driven, either from outside by motions or locally by a resistivity enhancement. Various processes are described that may occur during the nonlinear development of tearing, along with the many numerical and laboratory experiments that are aiding our understanding of this intriguing cosmical process.

  11. The current status of psychotherapy.

    PubMed

    Gureje, Oye

    2004-01-01

    Psychotherapy has a long history but its practice has always been strewn with controversy. In this review, the current status of psychotherapy is examined by setting its development in historical perspective. While previous practice was often based on the pronouncements of "masters", current approaches are almost always embedded in both rigorous theoretical formulations and frequently also in empirically derived data on efficacy. A fundamental understanding about the mechanisms of action of psychotherapy is a promising new development that is emanating from modern techniques of neurosciences and neuroimaging. Whether such understanding will lead to a renaissance in the clinical utility of psychotherapy is still early to say. However, there is little doubt that the provision of a holistic care for patients with psychological and mental disorders in particular, and most physical conditions in general, should be informed by an appreciation of the bi-directional nature of the relationship between the mind and the body and should therefore include the provision of appropriate psychotherapeutic interventions. PMID:15287283

  12. Current research on fatigue cracks

    SciTech Connect

    Tanaka, T.; Jono, M.; Komai, K.

    1987-01-01

    This first volume of CJMR (Current Japanese Materials Research), contains thirteen chapters concerning the above three themes of fatigue cracks. Each chapter is not a single paper as appearing in many academic journals and transactions, but a systematic review of the current achievement by each author with the emphasis on important points. The common feature is that the elaborated experimental techniques and theoretical approaches, some of which are quite unique, are introduced by respective authors to make clear the difficulty arising in the observation of small cracks and analysis of data. Theoretical models are proposed from the viewpoint of fracture mechanics to link the two thresholds of fatigue limit and crack growth, and intensive discussions are made for further development of the theory. Threshold stress intensity factors and the growth rate of medium and long sized cracks are also discussed, together with their opening behavior. The influencing factors are plastic zone size, the stress ratio and residual stress distribution occurring in welded joints. Mode II crack growth is of great significance since the initial fatigue cracks propagate mainly in shear mode. The problems of fatigue crack growth in corrosive environment is highly important since its retardation and enhancement take place in structural steels affected by the variety of factors. Life prediction in such environments poses another important problem. These are systematically discussed in this book.

  13. Past and Current Climate Change

    NASA Astrophysics Data System (ADS)

    Mercedes Rodríguez Ruibal, Ma

    2014-05-01

    In 1837 the Swiss geologist and palaeontologist Louis Agassiz was the first scientist to propose the existence of an ice age in the Earth's past. Nearly two centuries after discussing global glacial periods... while the average global temperature is rising very quickly because of our economic and industrial model. In tribute to these pioneers, we have selected a major climate change of the past as the Snowball Earth and, through various activities in the classroom, compared to the current anthropogenic climate change. First, we include multiple geological processes that led to a global glaciation 750 million years ago as the decrease in the atmospheric concentration of greenhouse gases such as CO2 and CH4, the effect of climate variations in solar radiation due to emissions of volcanic dust and orbital changes (Milankovitch cycles), being an essential part of this model the feedback mechanism of the albedo of the ice on a geological scale. Moreover, from simple experiments and studies in the classroom this time we can compare the past with the current anthropogenic global warming we are experiencing and some of its consequences, highlighting that affect sea level rise, increased extreme and effects on health and the biosphere weather.

  14. Wave/current interaction model

    NASA Technical Reports Server (NTRS)

    Liu, A. K.

    1988-01-01

    The wave-current interaction for the application to remote sensing data via numerical simulations and data comparison is modelled. Using the field data of surface current shear, wind condition and ambient wave spectrum, the numerical simulations of directional wave spectrum evolution were used to interpret and to compare with the aircraft data from Radar Ocean Wave Spectrometer (ROWS) and Surface Contour Radar (SCR) across the front during Frontal Air Sea Interaction Experiment (FASINEX). The wave-ice interaction was inspired by the observation of large amplitude waves hundreds of kms inside the ice pack in the Weddell Sea, resulting in breakup of the ice pack. The developed analysis of processes includes the refraction of waves at the pack edge, the effects of pack compression on wave propagation, wave train stability and buckling stability in the ice pack. Sources of pack compression and interaction between wave momentum and pack compression are investigated. Viscous camping of propagating waves in the marginal ice zone are also studied. The analysis suggests an explanation for the change in wave dispersion observed from the ship and the sequence of processes that cause ice pack breakup, pressure ridge formation and the formation of open bands of water.

  15. Current procedural terminology; a primer.

    PubMed

    Hirsch, Joshua A; Leslie-Mazwi, Thabele M; Nicola, Gregory N; Barr, Robert M; Bello, Jacqueline A; Donovan, William D; Tu, Raymond; Alson, Mark D; Manchikanti, Laxmaiah

    2015-04-01

    In 1966, The American Medical Association (AMA) working with multiple major medical specialty societies developed an iterative coding system for describing medical procedures and services using uniform language, the Current Procedural Terminology (CPT) system. The current code set, CPT IV, forms the basis of reporting most of the services performed by healthcare providers, physicians and non-physicians as well as facilities allowing effective, reliable communication among physician and other providers, third parties and patients. This coding system and its maintenance has evolved significantly since its inception, and now goes well beyond its readily perceived role in reimbursement. Additional roles include administrative management, tracking new and investigational procedures, and evolving aspects of 'pay for performance'. The system also allows for local, regional and national utilization comparisons for medical education and research. Neurointerventional specialists use CPT category I codes regularly--for example, 36,215 for first-order cerebrovascular angiography, 36,216 for second-order vessels, and 37,184 for acute stroke treatment by mechanical means. Additionally, physicians add relevant modifiers to the CPT codes, such as '-26' to indicate 'professional charge only,' or '-59' to indicate a distinct procedural service performed on the same day. PMID:24589819

  16. Ultrasound modulates ion channel currents

    PubMed Central

    Kubanek, Jan; Shi, Jingyi; Marsh, Jon; Chen, Di; Deng, Cheri; Cui, Jianmin

    2016-01-01

    Transcranial focused ultrasound (US) has been demonstrated to stimulate neurons in animals and humans, but the mechanism of this effect is unknown. It has been hypothesized that US, a mechanical stimulus, may mediate cellular discharge by activating mechanosensitive ion channels embedded within cellular membranes. To test this hypothesis, we expressed potassium and sodium mechanosensitive ion channels (channels of the two-pore-domain potassium family (K2P) including TREK-1, TREK-2, TRAAK; NaV1.5) in the Xenopus oocyte system. Focused US (10 MHz, 0.3–4.9 W/cm2) modulated the currents flowing through the ion channels on average by up to 23%, depending on channel and stimulus intensity. The effects were reversible upon repeated stimulation and were abolished when a channel blocker (ranolazine to block NaV1.5, BaCl2 to block K2P channels) was applied to the solution. These data reveal at the single cell level that focused US modulates the activity of specific ion channels to mediate transmembrane currents. These findings open doors to investigations of the effects of  US on ion channels expressed in neurons, retinal cells, or cardiac cells, which may lead to important medical applications. The findings may also pave the way to the development of sonogenetics: a non-invasive, US-based analogue of optogenetics. PMID:27112990

  17. Current Ideas about Prebiological Compartmentalization

    PubMed Central

    Monnard, Pierre-Alain; Walde, Peter

    2015-01-01

    Contemporary biological cells are highly sophisticated dynamic compartment systems which separate an internal volume from the external medium through a boundary, which controls, in complex ways, the exchange of matter and energy between the cell’s interior and the environment. Since such compartmentalization is a fundamental principle of all forms of life, scenarios have been elaborated about the emergence of prebiological compartments on early Earth, in particular about their likely structural characteristics and dynamic features. Chemical systems that consist of potentially prebiological compartments and chemical reaction networks have been designed to model pre-cellular systems. These systems are often referred to as “protocells”. Past and current protocell model systems are presented and compared. Since the prebiotic formation of cell-like compartments is directly linked to the prebiotic availability of compartment building blocks, a few aspects on the likely chemical inventory on the early Earth are also summarized. PMID:25867709

  18. Current management of antenatal hydronephrosis.

    PubMed

    Yamaçake, Kleiton G R; Nguyen, Hiep T

    2013-02-01

    The strategy for the management of children with urinary tract anomalies has changed considerably as a result of the development of ultrasound equipment and techniques that allow for detailed fetal evaluation. Hydronephrosis is the most common urogenital anomaly detected, suggesting that an obstructive process may be potentially present. The goal of postnatal management is to identify and treat those patients whose renal function is at risk, while leaving alone the high percentage of patients who are at no risk of renal damage. This management involves a spectrum of radiological, medical, and surgical interventions for diagnosis, surveillance, and treatment. In this article, we review our current understanding of the natural history of antenatal hydronephrosis and its management. PMID:22836304

  19. Teaching of leprosy: current challenges*

    PubMed Central

    Alves, Cynthia Rossetti Portela; Ribeiro, Maria Mônica Freitas; Melo, Elza Machado; Araújo, Marcelo Grossi

    2014-01-01

    In the context of declining leprosy endemicity worldwide, keeping the interest in knowledge and expertise in leprosy alive has been a matter of concern. Approaching the problem only in primary care, without the proper integration with other levels of care in the health system fails to account for the complexity of the disease. Training professionals to work at different levels of health care is a current challenge. The objective of this review was to look for experiences related to the teaching of leprosy both in undergraduate courses in the field of health sciences and in training programs for professionals who work in patient care. We highlight the role of the dermatologist in the management of control programs, diagnosis and treatment of the disease, as well as in the continuous education of other health professionals. PMID:24937820

  20. NIOSH current intelligence bulletins: summaries

    SciTech Connect

    Not Available

    1988-09-01

    Summaries were offered of the current intelligence bulletins issued from January 20, 1975 to August of 1988. They include information on the following topics: chloroprene, trichloroethylene, ethylene dibromide, chrome pigment, asbestos, hexamethylphosphoric triamide, polychlorinated biphenyls, 4,4'-diaminodiphenylmethane, chloroform, radon daughters, dimethylcarbamoyl chloride, diethylcarbamoyl-chloride, explosive azide hazard, inorganic arsenic, nitrosamines in cutting fluids, metabolic precursors of beta-naphthylamine, 2-nitropropane, acrylonitrile, 2,4-diaminoanisole, tetrachloroethylene, trimellitic anhydride, ethylene thiourea, disulfiram, direct-blue-6, direct-black-38, direct-brown-95, benzidine derived dyes, ethylene dichloride, NIAX catalyst ESN, chloroethanes, vinyl halides, glycidyl ethers, epichlorohydrin, smoking, arsine poisoning, radiofrequency sealers and heaters, formaldehyde, ethylene oxide, silica flour, vibration syndrome, glycol ethers, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 1,3-butadiene, cadmium, monohalomethanes, dinitrotoluenes, methylene chloride, 4,4'-methylenedianiline, organic solvent neurotoxicity, mechanical power press injuries, and the carcinogenic effects of diesel exhaust.

  1. High current capacity electrical connector

    DOEpatents

    Bettis, Edward S.; Watts, Harry L.

    1976-01-13

    An electrical connector is provided for coupling high current capacity electrical conductors such as copper busses or the like. The connector is arranged in a "sandwiched" configuration in which a conductor plate contacts the busses along major surfaces thereof clamped between two stainless steel backing plates. The conductor plate is provided with a plurality of contact buttons affixed therein in a spaced array such that the caps of the buttons extend above the conductor plate surface to contact the busses. When clamping bolts provided through openings in the sandwiched arrangement are tightened, Belleville springs provided under the rim of each button cap are compressed and resiliently force the caps into contact with the busses' contacting surfaces to maintain a predetermined electrical contact area provided by the button cap tops. The contact area does not change with changing thermal or mechanical stresses applied to the coupled conductors.

  2. Rosacea: current state of epidemiology.

    PubMed

    Tan, Jerry; Berg, Mats

    2013-12-01

    Case definitions are critical in epidemiologic research. However, modern disease indicators must now consider complex data from gene-based research along with traditional clinical parameters. Rosacea is a skin disorder with multiple signs and symptoms. In individuals, these features may be multiple or one may predominate. While studies on the epidemiology of rosacea have previously been sparse, there has been a recent increase in research activity. A broader body of epidemiological information that includes a greater variety of countries beyond Northern Europe and general population-based demographics is needed. As there are operational issues in current case definitions of rosacea subtypes--rationalization and standardization--universal consistent applications in future research is also imperative. Further improvement in disease definition combining new research information along with clinical pragmatism should increase the accuracy of rosacea case ascertainment and facilitate further epidemiological research. PMID:24229634

  3. Conformable eddy current array delivery

    NASA Astrophysics Data System (ADS)

    Summan, Rahul; Pierce, Gareth; Macleod, Charles; Mineo, Carmelo; Riise, Jonathan; Morozov, Maxim; Dobie, Gordon; Bolton, Gary; Raude, Angélique; Dalpé, Colombe; Braumann, Johannes

    2016-02-01

    The external surface of stainless steel containers used for the interim storage of nuclear material may be subject to Atmospherically Induced Stress Corrosion Cracking (AISCC). The inspection of such containers poses a significant challenge due to the large quantities involved; therefore, automating the inspection process is of considerable interest. This paper reports upon a proof-of-concept project concerning the automated NDT of a set of test containers containing artificially generated AISCCs. An Eddy current array probe with a conformable padded surface from Eddyfi was used as the NDT sensor and end effector on a KUKA KR5 arc HW robot. A kinematically valid cylindrical raster scan path was designed using the KUKA|PRC path planning software. Custom software was then written to interface measurement acquisition from the Eddyfi hardware with the motion control of the robot. Preliminary results and analysis are presented from scanning two canisters.

  4. Current trends in cardiac rehabilitation

    PubMed Central

    Dafoe, W; Huston, P

    1997-01-01

    Cardiac rehabilitation can reduce mortality and morbidity for patients with many types of cardiac disease cost-effectively, yet is generally underutilized. Rehabilitation is helpful not only for patients who have had a myocardial infarction but also for those with stable angina or congestive heart failure or those who have undergone myocardial revascularization procedures, a heart transplant or heart valve surgery. The beneficial effects of rehabilitation include a reduction in the rate of death from cardiovascular disease, improved exercise tolerance, fewer cardiac symptoms, improved lipid levels, decreased cigarette smoking, improvement in psychosocial well-being and increased likelihood of return to work. Rehabilitation involves a multidisciplinary team that focuses on education, individually tailored exercise, risk-factor modification and the optimization of functional status and mental health. Current research trends in this area include the evaluation of new secondary-prevention modalities and alternative program options, such as home-based rehabilitation. PMID:9054823

  5. [Current immunotherapy of multiple sclerosis].

    PubMed

    Paul, F; Ruprecht, K

    2015-08-01

    Following the introduction of interferon beta 1b as the first immunomodulatory therapy for multiple sclerosis (MS) in 1993, there are currently nine substances or substance classes approved for the treatment of MS (i.e. alemtuzumab, azathioprine, dimethyl fumarate, fingolimod, glatiramer acetate, interferon beta, mitoxantrone, natalizumab and teriflunomide). Major developments during the last 5 years include the approval of orally administered medications (i.e. fingolimod, teriflunomide and dimethyl fumarate), a monoclonal antibody (alemtuzumab), as well as glatiramer acetate with an administration frequency three times a week and a pegylated formulation of interferon beta 1a. The broadened therapeutic options enable a more differentiated and individualized therapy of MS; however, evidence-based data for therapeutic decision-making relevant in clinical practice are not always available. Rare but potentially severe and even life-threatening side effects of immunotherapies for MS require continuous pharmacovigilance and adherence to risk management plans. PMID:26253589

  6. Current Management of Urethral Stricture

    PubMed Central

    Lee, Young Ju

    2013-01-01

    The surgical treatment of urethral stricture diseases is continually evolving. Although various surgical techniques are available for the treatment of anterior urethral stricture, no one technique has been identified as the method of choice. This article provides a brief updated review of the surgical options for the management of different sites and different types of anterior urethral stricture. This review also covers present controversies in urethral reconstruction. Among the various procedures available for treating urethral stricture, one-stage buccal mucosal graft urethroplasty is currently widely used. The choice of technique for urethroplasty for an individual case largely depends on the expertise of the surgeon. Therefore, urologists working in this field should keep themselves updated on the numerous surgical techniques to deal with any condition of the urethra that might surface at the time of surgery. PMID:24044088

  7. Current Ideas about Prebiological Compartmentalization.

    PubMed

    Monnard, Pierre-Alain; Walde, Peter

    2015-01-01

    Contemporary biological cells are highly sophisticated dynamic compartment systems which separate an internal volume from the external medium through a boundary, which controls, in complex ways, the exchange of matter and energy between the cell's interior and the environment. Since such compartmentalization is a fundamental principle of all forms of life, scenarios have been elaborated about the emergence of prebiological compartments on early Earth, in particular about their likely structural characteristics and dynamic features. Chemical systems that consist of potentially prebiological compartments and chemical reaction networks have been designed to model pre-cellular systems. These systems are often referred to as "protocells". Past and current protocell model systems are presented and compared. Since the prebiotic formation of cell-like compartments is directly linked to the prebiotic availability of compartment building blocks, a few aspects on the likely chemical inventory on the early Earth are also summarized. PMID:25867709

  8. HIGH CURRENT COAXIAL PHOTOMULTIPLIER TUBE

    DOEpatents

    Glass, N.W.

    1960-01-19

    A medium-gain photomultiplier tube having high current output, fast rise- time, and matched output impedance was developed. The photomultiplier tube comprises an elongated cylindrical envelope, a cylindrical anode supported at the axis of the envelope, a plurality of elongated spaced opaque areas on the envelope, and a plurality of light admitting windows. A photo-cathode is supported adjacent to each of the windows, and a plurality of secondary emissive dynodes are arranged in two types of radial arrays which are alternately positioned to fill the annular space between the anode and the envelope. The dynodes are in an array being radially staggered with respect to the dynodes in the adjacent array, the dynodes each having a portion arranged at an angle with respect to the electron path, such that electrons emitted by each cathode undergo multiplication upon impingement on a dynode and redirected flight to the next adjacent dynode.

  9. Biofield Science: Current Physics Perspectives.

    PubMed

    Kafatos, Menas C; Chevalier, Gaétan; Chopra, Deepak; Hubacher, John; Kak, Subhash; Theise, Neil D

    2015-11-01

    This article briefly reviews the biofield hypothesis and its scientific literature. Evidence for the existence of the biofield now exists, and current theoretical foundations are now being developed. A review of the biofield and related topics from the perspective of physical science is needed to identify a common body of knowledge and evaluate possible underlying principles of origin of the biofield. The properties of such a field could be based on electromagnetic fields, coherent states, biophotons, quantum and quantum-like processes, and ultimately the quantum vacuum. Given this evidence, we intend to inquire and discuss how the existence of the biofield challenges reductionist approaches and presents its own challenges regarding the origin and source of the biofield, the specific evidence for its existence, its relation to biology, and last but not least, how it may inform an integrated understanding of consciousness and the living universe. PMID:26665039

  10. Finnish geomagnetically induced currents project

    SciTech Connect

    Vilianen, A.; Pirjola, R. . Dept. of Geophysics)

    1995-01-01

    This article is a summary of Results of the Finnish Project on Geomagnetically Induced Currents,'' published in Surveys in Geophysics 15:383-408, Kluwer Academic Publishers, Netherlands, 1994. IVO and FMI carried out a 1-year GIC project from June 1991 to May 1992. The time of the project was a little after the sunspot maximum, and the geomagnetic activity was high; there were 34 major or severe magnetic storm days (A[sub k] index at least 50). The main aim was to derive reliable statistics of the occurrences of GICs at different sites of the Finnish 400 and 220 kV power systems. Besides the practical engineering purpose, the project is also geophysically relevant by providing a GIC data set usable for large-scale investigations of auroral ionospheric-magnetospheric processes and of the earth's structure.

  11. Chronic Lymphocytic Leukemia: Current Concepts.

    PubMed

    Yu, Eun-Mi; Kittai, Adam; Tabbara, Imad A

    2015-10-01

    Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in adults, and while in early, asymptomatic stages treatment is not indicated, the threat to the quality of life and increased mortality of patients posed by more advanced-stage disease necessitate therapeutic intervention. Guidelines of when and how to treat are not well-established because CLL is a disease of the elderly and it is important to balance preservation of functional status and control of the disease. Advances in molecular and genetic profiling has led to the ability to identify sub-groups of patients with CLL whose disease may respond to selected therapy. This review discusses current standard therapies in the major sub-groups of CLL based on age and functional status, in both the front-line and relapsed/refractory settings. It also provides a concise review of novel agents that have shown considerable efficacy in CLL. PMID:26408673

  12. Current trends in dental implants

    PubMed Central

    Gaviria, Laura; Salcido, John Paul; Guda, Teja

    2014-01-01

    Tooth loss is very a very common problem; therefore, the use of dental implants is also a common practice. Although research on dental implant designs, materials and techniques has increased in the past few years and is expected to expand in the future, there is still a lot of work involved in the use of better biomaterials, implant design, surface modification and functionalization of surfaces to improve the long-term outcomes of the treatment. This paper provides a brief history and evolution of dental implants. It also describes the types of implants that have been developed, and the parameters that are presently used in the design of dental implants. Finally, it describes the trends that are employed to improve dental implant surfaces, and current technologies used for the analysis and design of the implants. PMID:24868501

  13. Myasthenia Gravis—Current Concepts

    PubMed Central

    Herrmann, Christian; Lindstrom, Jon M.; Keesey, John C.; Mulder, Donald G.

    1985-01-01

    An edited summary of an Interdepartmental Conference arranged by the Department of Medicine of the UCLA School of Medicine, Los Angeles. The Director of Conferences is William M. Pardridge, MD, Associate Professor of Medicine. Current findings indicate that autoimmune myasthenia gravis is an acquired immune complex disorder of neuromuscular transmission in voluntary striated muscle. There is a break in immunologic tolerance leading to blocking and degradation of acetylcholine receptors, together with widening of the synaptic cleft associated with partial destruction, simplification and shortening of the postjunctional membrane. Thymic hyperplasia and thymoma may be present. A decremental response to nerve-muscle stimulation, blocking and jitter on single-fiber electromyography and circulating antibodies to acetylcholine receptor are detectable in most patients with generalized weakness. Although the cause of this abnormal immunologic mechanism remains to be discovered, anticholinesterases, corticosteroids, immunosuppressants, plasmapheresis or thymectomy (individually or in combination) provide control and better prognosis in most patients. ImagesFigure 1. PMID:3895751

  14. Current methods of labor induction.

    PubMed

    Swamy, Geeta K

    2012-10-01

    In 2009, approximately 23% of all pregnant women in the United States underwent induction of labor, which is more than double the incidence of 9.5% in 1990. The ultimate goal of labor induction is to achieve vaginal delivery by stimulating uterine contractions before the spontaneous onset of labor. Labor induction is clearly indicated when the benefits outweigh the maternal and fetal risks of continued gestation, as well as potential risks associated with the procedure. Many women undergoing labor induction require cervical ripening--a method to facilitate softening, thinning, and dilation of an unfavorable cervix--because it reduces the time to delivery and incidence of failed induction. This article summarizes currently available methods for labor induction and cervical ripening, advantages and disadvantages of various methods, and the safety and effectiveness of each method based on well-conducted clinical trials. PMID:23009967

  15. Underwater slow current turbo generator

    SciTech Connect

    Wracsaricht, L.J.

    1981-12-15

    A self-contained electrical generating device for placement in a naturally flowing stream. The generating device converts the kinetic energy generated by fluid flow or gravity contained within the flowing stream whether river or ocean current into useful electric energy using blade configuration and placement to maximize the usable energy. The present invention also using auxiliary means to increase the rate of flow of the fluid by the blades of the generator thus increasing the energy capable of conversion. The rotor and the stator are located radially outwardly from the rotating hub of the generating system and are supported by spoke like legs thus greatly reducing any resistance to water flow, minimizing the disturbance to the flowing stream and maximizing the relative linear velocity between the rotor and the stator.

  16. Current Knowledge on Pancreatic Cancer

    PubMed Central

    Iovanna, Juan; Mallmann, Maria Cecilia; Gonçalves, Anthony; Turrini, Olivier; Dagorn, Jean-Charles

    2012-01-01

    Pancreatic cancer is the fourth leading cause of cancer death with a median survival of 6 months and a dismal 5-year survival rate of 3–5%. The development and progression of pancreatic cancer are caused by the activation of oncogenes, the inactivation of tumor suppressor genes, and the deregulation of many signaling pathways. Therefore, the strategies targeting these molecules as well as their downstream signaling could be promising for the prevention and treatment of pancreatic cancer. However, although targeted therapies for pancreatic cancer have yielded encouraging results in vitro and in animal models, these findings have not been translated into improved outcomes in clinical trials. This failure is due to an incomplete understanding of the biology of pancreatic cancer and to the selection of poorly efficient or imperfectly targeted agents. In this review, we will critically present the current knowledge regarding the molecular, biochemical, clinical, and therapeutic aspects of pancreatic cancer. PMID:22655256

  17. Limitations of bootstrap current models

    NASA Astrophysics Data System (ADS)

    Belli, E. A.; Candy, J.; Meneghini, O.; Osborne, T. H.

    2014-04-01

    We assess the accuracy and limitations of two analytic models of the tokamak bootstrap current: (1) the well-known Sauter model (1999 Phys. Plasmas 6 2834, 2002 Phys. Plasmas 9 5140) and (2) a recent modification of the Sauter model by Koh et al (2012 Phys. Plasmas 19 072505). For this study, we use simulations from the first-principles kinetic code NEO as the baseline to which the models are compared. Tests are performed using both theoretical parameter scans as well as core-to-edge scans of real DIII-D and NSTX plasma profiles. The effects of extreme aspect ratio, large impurity fraction, energetic particles, and high collisionality are studied. In particular, the error in neglecting cross-species collisional coupling—an approximation inherent to both analytic models—is quantified. Furthermore, the implications of the corrections from kinetic NEO simulations on MHD equilibrium reconstructions is studied via integrated modeling with kinetic EFIT.

  18. Familial Mediterranean fever: current perspectives

    PubMed Central

    Sönmez, Hafize Emine; Batu, Ezgi Deniz; Özen, Seza

    2016-01-01

    Familial Mediterranean fever (FMF) is the most frequent monogenic autoinflammatory disease, and it is characterized by recurrent attacks of fever and polyserositis. The disease is associated with mutations in the MEFV gene encoding pyrin, which causes exaggerated inflammatory response through uncontrolled production of interleukin 1. The major long-term complication of FMF is amyloidosis. Colchicine remains the principle therapy, and the aim of treatment is to prevent acute attacks and the consequences of chronic inflammation. With the evolution in the concepts about the etiopathogenesis and genetics of the disease, we have understood that FMF is more complicated than an ordinary autosomal recessive monogenic disorder. Recently, recommendation sets have been generated for interpretation of genetic testing and genetic diagnosis of FMF. Here, we have reviewed the current perspectives in FMF in light of recent recommendations. PMID:27051312

  19. Current puzzles and future possibilities

    SciTech Connect

    Nagamiya, S.

    1982-02-01

    Four current puzzles and several future experimental possibilities in high-energy nuclear collision research are discussed. These puzzles are (1) entropy, (2) hydrodynamic flow, (3) anomalon, and (4) particle emission at backward angles in proton-nucleus collisions. The last one seems not to be directly related to the subject of the present school. But it is, because particle emission into the region far beyond the nucleon-nucleon kinematical limit is an interesting subject common for both proton-nucleus and nucleus-nucleus collisions, and the basic mechanism involved is strongly related in these two cases. Future experimental possibilities are described which include: (1) possibilities of studying multibaryonic excited states, (2) applications of neutron-rich isotopes, and (3) other needed experimental tasks. 72 references.

  20. Anorectal Human Papillomavirus: Current Concepts

    PubMed Central

    Assi, Roland; Reddy, Vikram; Einarsdottir, Hulda; Longo, Walter E.

    2014-01-01

    Increased anorectal human papillomavirus (HPV) infection is related to the recent trends in sexual behavior in both homosexual and heterosexual groups and prevalence of infection with human immunodeficiency virus (HIV). Clinical presentation and natural history depend on the serotype involved. HPV 6 and 11 are found in the benign wart. Local control can be achieved with a wide selection of surgical and topical techniques. HPV 16, 18, and 31 are found in dysplastic lesions and have the potential to progress to invasive anal squamous cell carcinoma. Recognition and early management of dysplastic lesions is crucial to prevent the morbidity and mortality associated with anal cancer. While low-grade lesions can be closely observed, high-grade lesions should be eradicated. Different strategies can be used to eradicate the disease while preserving anorectal function. Studies on the efficacy of vaccination on anorectal HPV showed promising results in select population groups and led to the recent expansion of current vaccination recommendations. PMID:25506286

  1. Rotating concave eddy current probe

    DOEpatents

    Roach, Dennis P.; Walkington, Phil; Rackow, Kirk A.; Hohman, Ed

    2008-04-01

    A rotating concave eddy current probe for detecting fatigue cracks hidden from view underneath the head of a raised head fastener, such as a buttonhead-type rivet, used to join together structural skins, such as aluminum aircraft skins. The probe has a recessed concave dimple in its bottom surface that closely conforms to the shape of the raised head. The concave dimple holds the probe in good alignment on top of the rivet while the probe is rotated around the rivet's centerline. One or more magnetic coils are rigidly embedded within the probe's cylindrical body, which is made of a non-conducting material. This design overcomes the inspection impediment associated with widely varying conductivity in fastened joints.

  2. NASA's Current Earth Science Program

    NASA Technical Reports Server (NTRS)

    Charles, Leslie Bermann

    1998-01-01

    NASA's Earth science program is a scientific endeavor whose goal is to provide long-term understanding of the Earth as an integrated system of land, water, air and life. A highly developed scientific knowledge of the Earth system is necessary to understand how the environment affects humanity, and how humanity may be affecting the environment. The remote sensing technologies used to gather the global environmental data used in such research also have numerous practical applications. Current applications of remote sensing data demonstrate their practical benefits in areas such as the monitoring of crop conditions and yields, natural disasters and forest fires; hazardous waste clean up; and tracking of vector-borne diseases. The long-term availability of environmental data is essential for the continuity of important research and applications efforts. NASA's Earth observation program has undergone many changes in the recent past.

  3. Biofield Science: Current Physics Perspectives

    PubMed Central

    Chevalier, Gaétan; Chopra, Deepak; Hubacher, John; Kak, Subhash; Theise, Neil D.

    2015-01-01

    This article briefly reviews the biofield hypothesis and its scientific literature. Evidence for the existence of the biofield now exists, and current theoretical foundations are now being developed. A review of the biofield and related topics from the perspective of physical science is needed to identify a common body of knowledge and evaluate possible underlying principles of origin of the biofield. The properties of such a field could be based on electromagnetic fields, coherent states, biophotons, quantum and quantum-like processes, and ultimately the quantum vacuum. Given this evidence, we intend to inquire and discuss how the existence of the biofield challenges reductionist approaches and presents its own challenges regarding the origin and source of the biofield, the specific evidence for its existence, its relation to biology, and last but not least, how it may inform an integrated understanding of consciousness and the living universe. PMID:26665039

  4. Fiber-optic currents measurements

    SciTech Connect

    Forman, P.R.; Looney, L.D.; Tabaka, L.J.

    1993-03-01

    Polarization maintaining pigtailed laser diodes have greatly increased the ease with which fiber-optic sensors for Faraday current measurements on large pulsed experiments can be deployed. 670, 830, and 1300 nm units are readily available. Such diode lasers can easily be mounted in an RF shielded box along with the simple electronics and batteries to power them. Our units measure 16.5 {times} 8 {times} 6 cm. and have a single external control; an on off switch. They use two 1.5 volt ``C`` cell batteries. By using an LT1073 chip in the electronics the batteries are an energy source rather than a voltage source. These units can provide 100 mA drive to a LT015MD laser diode so that 1 mW of 830 nm fight exits the fiber pigtail for up to 23 hours with no detectable droop in power. For the sensor element twisted single mode low birefringence fibers are wrapped around the region of interest. The fiber pigtail is fused to the sensor section so changes in alignment are avoided. The light exiting the fiber sensor section is immediately analyzed by a compact, 3 {times} 3.5 {times} 5 cm, bulk optical unit which outputs quadrature optical signals into two multimode fibers leading to detectors in a screen room. The system is thus completely free of ground loops and is as immune to noise as the screen room. These sensors have the usual advantages claimed for them and the all dielectric feature was the original reason for their use on our experiments. The ease of deployment however is not usually cited. On our Pegasus II experiment the need arose for a total current measurement at the main header of the capacitor banks. A single turn of optical fiber was easily strung in a 6.4 m diameter circle and attached to laser and analyzer in a few hours.

  5. Fiber-optic currents measurements

    SciTech Connect

    Forman, P.R.; Looney, L.D.; Tabaka, L.J.

    1993-01-01

    Polarization maintaining pigtailed laser diodes have greatly increased the ease with which fiber-optic sensors for Faraday current measurements on large pulsed experiments can be deployed. 670, 830, and 1300 nm units are readily available. Such diode lasers can easily be mounted in an RF shielded box along with the simple electronics and batteries to power them. Our units measure 16.5 [times] 8 [times] 6 cm. and have a single external control; an on off switch. They use two 1.5 volt C'' cell batteries. By using an LT1073 chip in the electronics the batteries are an energy source rather than a voltage source. These units can provide 100 mA drive to a LT015MD laser diode so that 1 mW of 830 nm fight exits the fiber pigtail for up to 23 hours with no detectable droop in power. For the sensor element twisted single mode low birefringence fibers are wrapped around the region of interest. The fiber pigtail is fused to the sensor section so changes in alignment are avoided. The light exiting the fiber sensor section is immediately analyzed by a compact, 3 [times] 3.5 [times] 5 cm, bulk optical unit which outputs quadrature optical signals into two multimode fibers leading to detectors in a screen room. The system is thus completely free of ground loops and is as immune to noise as the screen room. These sensors have the usual advantages claimed for them and the all dielectric feature was the original reason for their use on our experiments. The ease of deployment however is not usually cited. On our Pegasus II experiment the need arose for a total current measurement at the main header of the capacitor banks. A single turn of optical fiber was easily strung in a 6.4 m diameter circle and attached to laser and analyzer in a few hours.

  6. TOPICAL REVIEW: Electric current sensors: a review

    NASA Astrophysics Data System (ADS)

    Ripka, Pavel

    2010-11-01

    The review makes a brief overview of traditional methods of measurement of electric current and shows in more detail relatively new types of current sensors. These include Hall sensors with field concentrators, AMR current sensors, magneto-optical and superconducting current sensors. The influence of the magnetic core properties on the error of the current transformer shows why nanocrystalline materials are so advantageous for this application. Built-in CMOS current sensors are important tools for monitoring the health of integrated circuits. Of special industrial value are current clamps which can be installed without breaking the measured conductor. Parameters of current sensors are also discussed, including geometrical selectivity. This parameter specific for current sensors means the ability to suppress the influence of currents external to the sensor (including the position of the return conductor) and also suppress the influence on the position of the measured conductor with respect to the current.

  7. Current status of zirconia restoration.

    PubMed

    Miyazaki, Takashi; Nakamura, Takashi; Matsumura, Hideo; Ban, Seiji; Kobayashi, Taira

    2013-10-01

    During the past decade, zirconia-based ceramics have been successfully introduced into the clinic to fabricate fixed dental prostheses (FDPs), along with a dental computer-aided/computer-aided manufacturing (CAD/CAM) system. In this article (1) development of dental ceramics, (2) the current status of dental CAD/CAM systems, (3) CAD/CAM and zirconia restoration, (4) bond between zirconia and veneering ceramics, (5) bond of zirconia with resin-based luting agents, (6) surface finish of zirconia restoration and antagonist enamel wear, and (7) clinical evaluation of zirconia restoration are reviewed. Yttria partially stabilized tetragonal zirconia polycrystalline (Y-TZP) showed better mechanical properties and superior resistance to fracture than other conventional dental ceramics. Furthermore, ceria-stabilized tetragonal zirconia polycrystalline and alumina nanocomposites (Ce-TZP/A) had the highest fracture toughness and had resistance to low-temperature aging degradation. Both zirconia-based ceramics have been clinically available as an alternative to the metal framework for fixed dental prostheses (FDPs). Marginal adaptation of zirconia-based FDPs is acceptable for clinical application. The most frequent clinical complication with zirconia-based FDPs was chipping of the veneering porcelain that was affected by many factors. The mechanism for the bonding between zirconia and veneering ceramics remains unknown. There was no clear evidence of chemical bonding and the bond strength between zirconia and porcelain was lower than that between metal and porcelain. There were two alternatives proposed that might avoid chipping of veneering porcelains. One was hybrid-structured FDPs comprising CAD/CAM-fabricated porcelain parts adhering to a CAD/CAM fabricated zirconia framework. Another option was full-contour zirconia FDPs using high translucent zirconia. Combined application of silica coating and/or silane coupler, and 10-methacryloyloxydecyl dihydrogen phosphate is

  8. Current Status of GRAPE Project

    NASA Astrophysics Data System (ADS)

    Makino, J.

    2008-05-01

    I'll summarize the current status of GRAPE project. GRAPE-6, completed in 2002, has been used by a number of people, for a wide variety of problems such as planet formation, star cluster dynamics, galactic nuclei, and cosmology. In 2004, we started the development of the next-generation machine, GRAPE-DR. GRAPE-DR has a architecture radically different from that of previous GRAPEs. It does not have hardwired pipeline for gravitational force calculation but a large number of small and simple programmable processors. This change made it possible to apply GRAPE-DR to a wide range of problems to which GRAPE was not efficient, and at the same time it helps us to explore new algorithms for N-body simulations. The GRAPE-DR chip was completed in 2006, and second prototype board was completed in May 2007. We hope to have full production-level board commercially available by the end of year 2007. A single board will offer the theoretical peak speed of 2 Tflops, about 20 times as that of a single PCI card version of GRAPE-6.

  9. Burning mouth syndrome: Current concepts.

    PubMed

    Nasri-Heir, Cibele; Zagury, Julyana Gomes; Thomas, Davis; Ananthan, Sowmya

    2015-01-01

    Burning mouth syndrome (BMS) is a chronic pain condition. It has been described by the International Headache Society as "an intra-oral burning or dysesthetic sensation, recurring daily for more than 2 h/day for more than 3 months, without clinically evident causative lesions." BMS is frequently seen in women in the peri-menopausal and menopausal age group in an average female/male ratio of 7:1. The site most commonly affected is the anterior two-thirds of the tongue. The patient may also report taste alterations and oral dryness along with the burning. The etiopathogenesis is complex and is not well-comprehended. The more accepted theories point toward a neuropathic etiology, but the gustatory system has also been implicated in this condition. BMS is frequently mismanaged, partly because it is not well-known among healthcare providers. Diagnosis of BMS is made after other local and systemic causes of burning have been ruled out as then; the oral burning is the disease itself. The management of BMS still remains a challenge. Benzodiazepines have been used in clinical practice as the first-line medication in the pharmacological management of BMS. Nonpharmacological management includes cognitive behavioral therapy and complementary and alternative medicine (CAM). The aim of this review is to familiarize healthcare providers with the diagnosis, pathogenesis, and general characteristics of primary BMS while updating them with the current treatment options to better manage this group of patients. PMID:26929531

  10. Mevalonate kinase deficiency: current perspectives

    PubMed Central

    Favier, Leslie A; Schulert, Grant S

    2016-01-01

    Mevalonate kinase deficiency (MKD) is a recessively inherited autoinflammatory disorder with a spectrum of manifestations, including the well-defined clinical phenotypes of hyperimmunoglobulinemia D and periodic fever syndrome and mevalonic aciduria. Patients with MKD have recurrent attacks of hyperinflammation associated with fever, abdominal pain, arthralgias, and mucocutaneous lesions, and more severely affected patients also have dysmorphisms and central nervous system anomalies. MKD is caused by mutations in the gene encoding mevalonate kinase, with the degree of residual enzyme activity largely determining disease severity. Mevalonate kinase is essential for the biosynthesis of nonsterol isoprenoids, which mediate protein prenylation. Although the precise pathogenesis of MKD remains unclear, increasing evidence suggests that deficiency in protein prenylation leads to innate immune activation and systemic hyperinflammation. Given the emerging understanding of MKD as an autoinflammatory disorder, recent treatment approaches have largely focused on cytokine-directed biologic therapy. Herein, we review the current genetic and pathologic understanding of MKD, its various clinical phenotypes, and the evolving treatment approach for this multifaceted disorder. PMID:27499643

  11. Current understanding of auditory neuropathy.

    PubMed

    Boo, Nem-Yun

    2008-12-01

    Auditory neuropathy is defined by the presence of normal evoked otoacoustic emissions (OAE) and absent or abnormal auditory brainstem responses (ABR). The sites of lesion could be at the cochlear inner hair cells, spiral ganglion cells of the cochlea, synapse between the inner hair cells and auditory nerve, or the auditory nerve itself. Genetic, infectious or neonatal/perinatal insults are the 3 most commonly identified underlying causes. Children usually present with delay in speech and language development while adult patients present with hearing loss and disproportionately poor speech discrimination for the degree of hearing loss. Although cochlear implant is the treatment of choice, current evidence show that it benefits only those patients with endocochlear lesions, but not those with cochlear nerve deficiency or central nervous system disorders. As auditory neuropathy is a disorder with potential long-term impact on a child's development, early hearing screen using both OAE and ABR should be carried out on all newborns and infants to allow early detection and intervention. PMID:19904452

  12. Current status of renal transplantation.

    PubMed Central

    Suranyi, M. G.; Hall, B. M.

    1990-01-01

    The success rate of renal transplantation has improved considerably during the past decade, with substantial improvements in both graft and patient survival. The quality of graft function, however, and not graft survival alone is increasingly determining the standards by which transplantation outcome is being judged. As the demand for kidney transplants continues to rise and transplants are being offered to an ever-increasing number of patients, organs are being sought from new supply pools and efforts are being made to use current resources more efficiently. Improvements in clinical management have allowed short-term complications such as infection and rejection to be better prevented or better diagnosed and treated. Fundamental advances in the understanding of the immunologic processes underlying both allograft rejection and acceptance and the introduction of new immunosuppressive agents have allowed a better use of drug therapy and have moved the goal of acquired transplant tolerance closer to attainment. With improved initial transplant success rates, the long-term transplantation outcome is becoming more important. The role of tissue matching in preventing chronic rejection is becoming more appreciated, and the long-term risks of malignancy, arteriosclerosis, and chronic rejection are being better recognized and managed. PMID:2191502

  13. Nanodosimetry: Principle and Current Status

    NASA Astrophysics Data System (ADS)

    Schulte, Reinhard W.

    2011-05-01

    Due to the success of theoretical track structure Monte Carlo simulations, showing that features of ionization patterns on the nanometer level are important for the biological effectiveness of ionizing radiation, several new methods for experimental track structure investigations have been developed in recent years. These methods all use the principle of density scaling in low-pressure gas to probe track structure in macroscopic dimensions, ideally with single-ionization resolution. The new field of experimental track structure investigation, which has been called nanodosimetry, can be approached in two ways: (1) the number of ionizations in a defined, ideally wall-less, sensitive volume is registered per single primary particle and cluster size distributions are obtained, or (2) the full track structure of an ion track segment is "imaged". Existing nanodosimetric methods are based on the first approach, but a track structure imaging detector is currently under development at Loma Linda University. This contribution will review the principle and existing technical approaches to nanodosimetry and will give an outlook on future developments and applications.

  14. Current Legislative Initiatives and Geophysics

    NASA Astrophysics Data System (ADS)

    Stephan, S. G.

    2002-05-01

    Geophysical research will be most effective in the fight against terrorism if it is done in cooperation with the expectations of local, state and federal policy makers. New tools to prevent, prepare for, and respond to acts of terrorism are coming from all fields, including geoscience. Globally, monitoring the land, oceans, atmosphere, and space for unusual and suspicious activities can help prevent terrorist acts. Closer to home, geoscience research is used to plan emergency transportation routes and identify infrastructure vulnerabilities. As important as it is for Congress and other policy makers to appreciate the promises and limitations of geophysical research, scientists need to be aware of legislative priorities and expectations. What does Congress expect from the geoscience community in the fight against terrorism and how well does reality meet these expectations? What tools do the 44 different federal agencies with stated Homeland Security missions need from geoscientists? I will address these questions with an overview of current legislative antiterrorism initiatives and policies that relate to the geoscience community.

  15. Current perspectives on glycopeptide resistance.

    PubMed Central

    Woodford, N; Johnson, A P; Morrison, D; Speller, D C

    1995-01-01

    In the last 5 years, clinical isolates of gram-positive bacteria with intrinsic or acquired resistance to glycopeptide antibiotics have been encountered increasingly. In many of these isolates, resistance arises from an alteration of the antibiotic target site, with the terminal D-alanyl-D-alanine moiety of peptidoglycan precursors being replaced by groups that do not bind glycopeptides. Although the criteria for defining resistance have been revised frequently, the reliable detection of low-level glycopeptide resistance remains problematic and is influenced by the method chosen. Glycopeptide-resistant enterococci have emerged as a particular problem in hospitals, where in addition to sporadic cases, clusters of infections with evidence of interpatient spread have occurred. Studies using molecular typing methods have implicated colonization of patients, staff carriage, and environmental contamination in the dissemination of these bacteria. Choice of antimicrobial therapy for infections caused by glycopeptide-resistant bacteria may be complicated by resistance to other antibiotics. Severe therapeutic difficulties are being encountered among patients infected with enterococci, with some infections being untreatable with currently available antibiotics. PMID:8665471

  16. Flux focusing eddy current probe

    NASA Technical Reports Server (NTRS)

    Simpson, John W. (Inventor); Clendenin, C. Gerald (Inventor); Fulton, James P. (Inventor); Wincheski, Russell A. (Inventor); Todhunter, Ronald G. (Inventor); Namkung, Min (Inventor); Nath, Shridhar C. (Inventor)

    1997-01-01

    A flux-focusing electromagnetic sensor which uses a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks and material loss in high conductivity material. The unique feature of the device is the ferrous shield isolating a high-turn pick-up coil from an excitation coil. The use of the magnetic shield is shown to produce a null voltage output across the receiving coil in the presence of an unflawed sample. A redistribution of the current flow in the sample caused by the presence of flaws, however, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal. The maximum sensor output is obtained when positioned symmetrically above the crack. Hence, by obtaining the position of the maximum sensor output, it is possible to track the fault and locate the area surrounding its tip. The accuracy of tip location is enhanced by two unique features of the sensor; a very high signal-to-noise ratio of the probe's output which results in an extremely smooth signal peak across the fault, and a rapidly decaying sensor output outside a small area surrounding the crack tip which enables the region for searching to be clearly defined. Under low frequency operation, material thinning due to corrosion damage causes an incomplete shielding of the pick-up coil. The low frequency output voltage of the probe is therefore a direct indicator of the thickness of the test sample.

  17. Current Treatments for Alopecia Areata.

    PubMed

    Hordinsky, Maria K

    2015-11-01

    Selection of a therapy for a patient with alopecia areata (AA) is frequently based on the age of the patient, disease extent, perhaps disease duration, patient expectations, cost of therapy in terms of time commitment, and financial resources, as well as the results of screening laboratory studies that rule out the presence of other co-morbidities such as anemia, low iron stores, thyroid abnormalities, low vitamin D, or other autoimmune diseases. Although there is currently no cure for AA and no universally proven therapy that induces and sustains remission, many therapies are available which can be of benefit to both affected children and adults. Before selecting a treatment for patients with extensive long-standing AA, a scalp biopsy may provide useful information about the degree of inflammation and follicle differentiation. Recent clinical and translational research observations with the systemic Janus kinase (JAK) inhibitors and interleukin-2 (IL-2) have excited the clinical and AA patient communities and have led to clinical trials, as well as to the off-label use of these more expensive and targeted systemic therapies. PMID:26551946

  18. Current Treatments in Familial Dysautonomia

    PubMed Central

    Palma, Jose-Alberto; Kaufmann, Lucy; Fuente, Cristina; Percival, Leila; Mendoza, Carlos; Kaufmann, Horacio

    2014-01-01

    Introduction Familial dysautonomia (FD) is a rare hereditary sensory and autonomic neuropathy (type III). The disease is caused by a point mutation in the IKBKAP gene that affects the splicing of the elongator-1 protein (also known as IKAP). Patients have dramatic blood pressure instability due to baroreflex failure, chronic kidney disease, and impaired swallowing leading to recurrent aspiration pneumonia, which results in chronic lung disease. Diminished pain and temperature perception results in neuropathic joints and thermal injuries. Impaired proprioception leads to gait ataxia. Optic neuropathy and corneal opacities lead to progressive visual loss. Areas covered This article reviews current therapeutic strategies for the symptomatic treatment of FD, as well as the potential of new gene modifying agents. Expert opinion Therapeutic focus on FD is centered on reducing the catecholamine surges caused by baroreflex failure. Managing neurogenic dysphagia with effective protection of the airway passages and prompt treatment of aspiration pneumonias is necessary to prevent respiratory failure. Sedative medications should be used cautiously due to risk of respiratory depression. Non-invasive ventilation during sleep effectively manages apneas and prevents hypercapnia. Clinical trials of compounds that increase levels of IKAP (ELP-1) are underway and will determine whether they can reverse or slow disease progression. PMID:25323828

  19. Classification of current scoring functions.

    PubMed

    Liu, Jie; Wang, Renxiao

    2015-03-23

    Scoring functions are a class of computational methods widely applied in structure-based drug design for evaluating protein-ligand interactions. Dozens of scoring functions have been published since the early 1990s. In literature, scoring functions are typically classified as force-field-based, empirical, and knowledge-based. This classification scheme has been quoted for more than a decade and is still repeatedly quoted by some recent publications. Unfortunately, it does not reflect the recent progress in this field. Besides, the naming convention used for describing different types of scoring functions has been somewhat jumbled in literature, which could be confusing for newcomers to this field. Here, we express our viewpoint on an up-to-date classification scheme and appropriate naming convention for current scoring functions. We propose that they can be classified into physics-based methods, empirical scoring functions, knowledge-based potentials, and descriptor-based scoring functions. We also outline the major difference and connections between different categories of scoring functions. PMID:25647463

  20. Current work in energy analysis

    SciTech Connect

    1998-03-01

    This report describes the work performed at Berkeley Lab most recently. One of the Labs accomplishments is the publication of Scenarios of US Carbon Reductions, an analysis of the potential of energy technologies to reduce carbon emissions in the US. This analysis is described and played a key role in shaping the US position on climate change in the Kyoto Protocol negotiations. The Labs participation in the fundamental characterization of the climate change issue by the IPCC is described. Described also is a study of leaking electricity, which is stimulating an international campaign for a one-watt ceiling for standby electricity losses from appliances. This ceiling has the potential to save two-thirds of the 5% of US residential electricity currently expended on standby losses. The 54 vignettes contained in the report summarize results of research activities ranging in scale from calculating the efficacy of individual lamp ballasts to estimating the cost-effectiveness of the national Energy Star{reg_sign} labeling program, and ranging in location from a scoping study of energy-efficiency market transformation in California to development of an energy-efficiency project in the auto parts industry in Shandong Province, China.

  1. Current advances in orthodontic pain

    PubMed Central

    Long, Hu; Wang, Yan; Jian, Fan; Liao, Li-Na; Yang, Xin; Lai, Wen-Li

    2016-01-01

    Orthodontic pain is an inflammatory pain that is initiated by orthodontic force-induced vascular occlusion followed by a cascade of inflammatory responses, including vascular changes, the recruitment of inflammatory and immune cells, and the release of neurogenic and pro-inflammatory mediators. Ultimately, endogenous analgesic mechanisms check the inflammatory response and the sensation of pain subsides. The orthodontic pain signal, once received by periodontal sensory endings, reaches the sensory cortex for pain perception through three-order neurons: the trigeminal neuron at the trigeminal ganglia, the trigeminal nucleus caudalis at the medulla oblongata and the ventroposterior nucleus at the thalamus. Many brain areas participate in the emotion, cognition and memory of orthodontic pain, including the insular cortex, amygdala, hippocampus, locus coeruleus and hypothalamus. A built-in analgesic neural pathway—periaqueductal grey and dorsal raphe—has an important role in alleviating orthodontic pain. Currently, several treatment modalities have been applied for the relief of orthodontic pain, including pharmacological, mechanical and behavioural approaches and low-level laser therapy. The effectiveness of nonsteroidal anti-inflammatory drugs for pain relief has been validated, but its effects on tooth movement are controversial. However, more studies are needed to verify the effectiveness of other modalities. Furthermore, gene therapy is a novel, viable and promising modality for alleviating orthodontic pain in the future. PMID:27341389

  2. The status of neutral currents

    SciTech Connect

    Zwirner, F.

    1987-11-01

    The situation of particle physics today is quite puzzling. On the one hand, the Standard Model (SM) of strong and electroweak interactions is consistent with all confirmed experimental data but theoretically rather unsatisfactory. On the other hand, none of the many theoretical speculations which try to go beyond the SM has (yet) received the slightest experimental support. The solution to this dilemma can only come from new data: either from the detection of a new particle threshold at high energy colliders, or from the appearance of some small discrepancy in high-precision experiments. A crucial sector for testing the SM and its extensions is that of neutral currents (NC), where an impressive amount of data has been collected in recent years. While waiting for the next generation of experiments, it is certainly useful to take stock of our knowledge, determining the NC parameters as precisely as we can and putting limits on possible deviations from the SM. The present talk contains the results of a recent analysis along these lines: the first part illustrates how a set of 'model-independent' parameters can be extracted from the available NC data, the second part particularizes the analysis to the SM and to some superstring-inspired models with an additional Z' in their low-energy spectrum. 27 refs., 3 figs., 1 tab.

  3. Current aspects of vitiligo genetics

    PubMed Central

    Męcińska-Jundziłł, Kaja

    2014-01-01

    Vitiligo is a common acquired depigmentation disorder of the skin manifested by the presence of white macules. The disease occurs at a frequency of approximately 1–4% of the world population. Currently, the most popular theory of vitiligo development is a multifactorial hypothesis according to which genetic conditions predispose vitiligo macules to occur as a result of specific environmental factors. According to the genetic hypothesis, vitiligo inheritance is multigenic. Genetic studies conducted so far concern patients with non-segmental vitiligo. There are three basic techniques of genetic studies: candidate gene association studies, genomewide linkage studies and genome-wide association studies (GWAS). The GWAS are the “gold standard” for detecting susceptibility genes. Up to now, approximately 36 convincing non-segmental vitiligo susceptibility loci have been identified. Approximately 90% of them encode immunoregulatory proteins, while approximately 10% encode melanocyte proteins. The existence of various associations between vitiligo and other autoimmune diseases may provide new knowledge on the causes of many disorders. Examples include the inverse relationship between vitiligo and melanoma and association of vitiligo with other autoimmune diseases. The main goal of all researches is to find new, optimal therapeutic strategies for vitiligo and other autoimmune diseases. PMID:25254010

  4. Nanodosimetry: Principle and Current Status

    SciTech Connect

    Schulte, Reinhard W.

    2011-05-05

    Due to the success of theoretical track structure Monte Carlo simulations, showing that features of ionization patterns on the nanometer level are important for the biological effectiveness of ionizing radiation, several new methods for experimental track structure investigations have been developed in recent years. These methods all use the principle of density scaling in low-pressure gas to probe track structure in macroscopic dimensions, ideally with single-ionization resolution. The new field of experimental track structure investigation, which has been called nanodosimetry, can be approached in two ways: (1) the number of ionizations in a defined, ideally wall-less, sensitive volume is registered per single primary particle and cluster size distributions are obtained, or (2) the full track structure of an ion track segment is 'imaged'. Existing nanodosimetric methods are based on the first approach, but a track structure imaging detector is currently under development at Loma Linda University. This contribution will review the principle and existing technical approaches to nanodosimetry and will give an outlook on future developments and applications.

  5. Current advances in orthodontic pain.

    PubMed

    Long, Hu; Wang, Yan; Jian, Fan; Liao, Li-Na; Yang, Xin; Lai, Wen-Li

    2016-01-01

    Orthodontic pain is an inflammatory pain that is initiated by orthodontic force-induced vascular occlusion followed by a cascade of inflammatory responses, including vascular changes, the recruitment of inflammatory and immune cells, and the release of neurogenic and pro-inflammatory mediators. Ultimately, endogenous analgesic mechanisms check the inflammatory response and the sensation of pain subsides. The orthodontic pain signal, once received by periodontal sensory endings, reaches the sensory cortex for pain perception through three-order neurons: the trigeminal neuron at the trigeminal ganglia, the trigeminal nucleus caudalis at the medulla oblongata and the ventroposterior nucleus at the thalamus. Many brain areas participate in the emotion, cognition and memory of orthodontic pain, including the insular cortex, amygdala, hippocampus, locus coeruleus and hypothalamus. A built-in analgesic neural pathway-periaqueductal grey and dorsal raphe-has an important role in alleviating orthodontic pain. Currently, several treatment modalities have been applied for the relief of orthodontic pain, including pharmacological, mechanical and behavioural approaches and low-level laser therapy. The effectiveness of nonsteroidal anti-inflammatory drugs for pain relief has been validated, but its effects on tooth movement are controversial. However, more studies are needed to verify the effectiveness of other modalities. Furthermore, gene therapy is a novel, viable and promising modality for alleviating orthodontic pain in the future. PMID:27341389

  6. Laser ultrasonics: Current research needs

    SciTech Connect

    Wagner, J.W. . Center for Nondestructive Evaluation)

    1990-09-26

    Laser-ultrasonics refers to a range of technologies involving the use of laser electrooptical systems both to generate and to detect ultrasonic signals in and on materials and structures. Such systems have been developed to permit classical ultrasonic measurements for materials characterization and defect identification and measurement. From the point of view of one concerned with practical applications of ultrasonic inspection and measurement methods, laser-ultrasonic systems offer the flexibility which, in principle, should permit remote ultrasonic measurements to be performed on objects at elevated temperatures or in hostile environments. Laser-ultrasonic systems can be designed and constructed with extremely wide and flat detection bandwidth so that ultrasonic vibrational displacements can be recorded with high fidelity. In addition, there is no mechanical loading of the surface to damp, absorb, or otherwise distort the propagating acoustic energy. This feature has been used to great advantage in performing ultrasonic measurements in thin plates and films. In spite of the great advantages offered by laser-ultrasonics, there are severe limitations which restrict its application. In fact, based upon the performance of current state-of-the-art laser-ultrasonic systems, it is almost always more advantageous to use conventional ultrasonic transduction methods, if possible for a given application, than it is to apply laser-ultrasonics. In short, the main reason leading to this conclusion is the poor system detection sensitivity of laser-ultrasonic systems compared with piezoelectric transducer systems. The ramifications of this limited sensitivity are many.

  7. Measurement of the Strange Quark Contribution to Nucleon Structure Through Parity-Violating Electron Scattering

    SciTech Connect

    Ellis, Colleen

    2010-01-01

    The G0 backward angle experiment, completed in Hall C of the Thomas Jefferson National Accelerator Facility (TJNAF), measured parity-violating asymmetries in elastic electron-proton and quasielastic electron-deuteron scattering at Q2 = 0.22 and 0.63 (GeV/c)2. The asymmetries are sensitive to strange quark contributions to currents in the nucleon and the nucleon axial-vector current. The results indicate strange quark contributions of ≤ 10% of the charge and magnetic nucleon form factors at these four-momentum transfers. This was also the first measurement of the anapole moment effects in the axial-vector current at these four-momentum transfers.

  8. 48 CFR 53.102 - Current editions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Current editions. 53.102... AND FORMS FORMS General 53.102 Current editions. The form prescriptions in subpart 53.2 and the illustrations in subpart 53.3 contain current edition dates. Contracting officers shall use the current...

  9. 48 CFR 53.102 - Current editions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 2 2014-10-01 2014-10-01 false Current editions. 53.102... AND FORMS FORMS General 53.102 Current editions. The form prescriptions in subpart 53.2 and the illustrations in subpart 53.3 contain current edition dates. Contracting officers shall use the current...

  10. 48 CFR 53.102 - Current editions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Current editions. 53.102... AND FORMS FORMS General 53.102 Current editions. The form prescriptions in subpart 53.2 and the illustrations in subpart 53.3 contain current edition dates. Contracting officers shall use the current...

  11. 48 CFR 53.102 - Current editions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 2 2013-10-01 2013-10-01 false Current editions. 53.102... AND FORMS FORMS General 53.102 Current editions. The form prescriptions in subpart 53.2 and the illustrations in subpart 53.3 contain current edition dates. Contracting officers shall use the current...

  12. 48 CFR 53.102 - Current editions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 2 2011-10-01 2011-10-01 false Current editions. 53.102... AND FORMS FORMS General 53.102 Current editions. The form prescriptions in subpart 53.2 and the illustrations in subpart 53.3 contain current edition dates. Contracting officers shall use the current...

  13. Defining and resolving current systems in geospace

    NASA Astrophysics Data System (ADS)

    Ganushkina, N. Y.; Liemohn, M. W.; Dubyagin, S.; Daglis, I. A.; Dandouras, I.; De Zeeuw, D. L.; Ebihara, Y.; Ilie, R.; Katus, R.; Kubyshkina, M.; Milan, S. E.; Ohtani, S.; Ostgaard, N.; Reistad, J. P.; Tenfjord, P.; Toffoletto, F.; Zaharia, S.; Amariutei, O.

    2015-11-01

    Electric currents flowing through near-Earth space (R ≤ 12 RE) can support a highly distorted magnetic field topology, changing particle drift paths and therefore having a nonlinear feedback on the currents themselves. A number of current systems exist in the magnetosphere, most commonly defined as (1) the dayside magnetopause Chapman-Ferraro currents, (2) the Birkeland field-aligned currents with high-latitude "region 1" and lower-latitude "region 2" currents connected to the partial ring current, (3) the magnetotail currents, and (4) the symmetric ring current. In the near-Earth nightside region, however, several of these current systems flow in close proximity to each other. Moreover, the existence of other temporal current systems, such as the substorm current wedge or "banana" current, has been reported. It is very difficult to identify a local measurement as belonging to a specific system. Such identification is important, however, because how the current closes and how these loops change in space and time governs the magnetic topology of the magnetosphere and therefore controls the physical processes of geospace. Furthermore, many methods exist for identifying the regions of near-Earth space carrying each type of current. This study presents a robust collection of these definitions of current systems in geospace, particularly in the near-Earth nightside magnetosphere, as viewed from a variety of observational and computational analysis techniques. The influence of definitional choice on the resulting interpretation of physical processes governing geospace dynamics is presented and discussed.

  14. Steady State Tokamak Equilibria without Current Drive

    SciTech Connect

    Shaing, K.C.; Aydemir, A.Y.; Lin-Liu, Y.R.; Miller, R.L.

    1997-11-01

    Steady state tokamak equilibria without current drive are found. This is made possible by including the potato bootstrap current close to the magnetic axis. Tokamaks with this class of equilibria do not need seed current or current drive, and are intrinsically steady state. {copyright} {ital 1997} {ital The American Physical Society}

  15. Observations of Birkeland currents. [effects on auroras

    NASA Technical Reports Server (NTRS)

    Cloutier, P. A.; Anderson, H. R.

    1975-01-01

    Recent measurements of precipitating energetic particles and vector magnetic fields from satellites and sounding rockets have verified the existence of geomagnetically-aligned electric currents at high latitudes in the ionosphere and magnetosphere. The spatial and temporal configuration of such currents, now commonly called Birkeland currents, has delineated their role in providing ionospheric closure of magnetospheric current systems, and gross features of these current systems may be understood in terms of theoretical models of magnetospheric convection. The association of Birkeland currents with auroral features on a very small scale suggests that auroral acceleration may result from the current flow.

  16. Thinning of current sheets and magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Singh, N.; Deverapalli, C.

    Using three-dimensional particle-in-cell (3DPIC) simulations, we study the formation of a thin current sheet. The processes associated with thin current sheets reported here include its thinning, associated potential well in its central part, ion acceleration into the well, current-driven ion mode instabilities, electron and ion heating, current sheet re- broadening, current disruption in the central part of the current sheet and magnetic reconnection. It is shown that current driven instabilities become explosive when the preferential heating of electrons by the ions make electron temperature higher than that of the ions. This explosive stage is associated with high plasma resistivity, current disruption and bifurcated current sheets. The current disruption is linked to the magnetic reconnection.

  17. Bootstrapped tokamak with oscillating field current drive

    SciTech Connect

    Weening, R.H. )

    1993-07-01

    A magnetic helicity conserving mean-field Ohm's law is used to study bootstrapped tokamaks with oscillating field current drive. The Ohm's law leads to the conclusion that the tokamak bootstrap effect can convert the largely alternating current of oscillating field current drive into a direct toroidal plasma current. This plasma current rectification is due to the intrinsically nonlinear nature of the tokamak bootstrap effect, and suggests that it may be possible to maintain the toroidal current of a tokamak reactor by supplementing the bootstrap current with oscillating field current drive. Steady-state tokamak fusion reactors operating with oscillating field current drive could provide an alternative to tokamak reactors operating with external current drive.

  18. Current trends in geomorphological mapping

    NASA Astrophysics Data System (ADS)

    Seijmonsbergen, A. C.

    2012-04-01

    Geomorphological mapping is a world currently in motion, driven by technological advances and the availability of new high resolution data. As a consequence, classic (paper) geomorphological maps which were the standard for more than 50 years are rapidly being replaced by digital geomorphological information layers. This is witnessed by the following developments: 1. the conversion of classic paper maps into digital information layers, mainly performed in a digital mapping environment such as a Geographical Information System, 2. updating the location precision and the content of the converted maps, by adding more geomorphological details, taken from high resolution elevation data and/or high resolution image data, 3. (semi) automated extraction and classification of geomorphological features from digital elevation models, broadly separated into unsupervised and supervised classification techniques and 4. New digital visualization / cartographic techniques and reading interfaces. Newly digital geomorphological information layers can be based on manual digitization of polygons using DEMs and/or aerial photographs, or prepared through (semi) automated extraction and delineation of geomorphological features. DEMs are often used as basis to derive Land Surface Parameter information which is used as input for (un) supervised classification techniques. Especially when using high-res data, object-based classification is used as an alternative to traditional pixel-based classifications, to cluster grid cells into homogeneous objects, which can be classified as geomorphological features. Classic map content can also be used as training material for the supervised classification of geomorphological features. In the classification process, rule-based protocols, including expert-knowledge input, are used to map specific geomorphological features or entire landscapes. Current (semi) automated classification techniques are increasingly able to extract morphometric, hydrological

  19. Current status of mold immunotherapy.

    PubMed

    Dhillon, M

    1991-05-01

    There is evidence to suggest that molds can cause IgE-mediated upper respiratory tract disorders and immunotherapy is efficacious in a select group. The environmental sampling studies show a remarkably small numbers of molds accounting for a majority of the mold load in various diverse locations. These are Cladosporium, Basidiospores, Aspergillus, and Alternaria-Penicillin families. Basidiospores have been underreported in the older studies because of difficulties in their identification. Whether the absolute mold level is the most important factor leading to IgE formation and induction of upper respiratory tract symptoms is uncertain. Certainly, the majority of the studies are based on the assumption that the absolute level of mold in the environment is the most important factor leading to the development of symptoms, but this is not based on strong evidence. A major problem in the majority of the studies is a lack of standardization of extracts which may lead to false negatives on skin testing and thus produce variable data in population evaluations comparing the prevalence of mold to its ability to induce IgE production and symptoms. The best current trials to document the efficacy of mold immunotherapy have been with the standardized Cladosporium extract. Unfortunately, these results cannot be extrapolated to the commercially available mold extracts available in the United States either for immunotherapy or for skin testing. These extracts are highly variable in their potency, prone to high false negative rates, and at best serve as poor skin testing reagents and possibly even worse immunotherapy reagents. Adequately standardized mold reagents are urgently needed to determine whether the Cladosporium data can be extrapolated to them in any meaningful way. PMID:2035901

  20. Current Knowledge on Hepatitis E.

    PubMed

    Pérez-Gracia, María Teresa; García, Mario; Suay, Beatriz; Mateos-Lindemann, María Luisa

    2015-06-28

    Although only a single serotype of hepatitis E virus (HEV), the causative agent of hepatitis E, has been identified, there is great genetic variation among the different HEV isolates reported. There are at least four major recognized genotypes of HEV: genotypes 1 and 2 are mainly restricted to humans and linked to epidemic outbreaks in nonindustrialized countries, whereas genotypes 3 and 4 are zoonotic in both developing and industrialized countries. Besides human strains, genotype 3 and 4 strains of HEV have been genetically characterized from swine, sika deer, mongooses, sheep, and rabbits. Currently, there are approximately 11,000 human and animal sequences of HEV available at the International Nucleotide Sequence Database Collaboration. HEV is the major cause of waterborne outbreaks of hepatitis in areas of poor sanitation. Additionally, it is responsible for sporadic cases of viral hepatitis in not only endemic but industrialized countries as well. Transmission of HEV occurs predominantly by the fecal-oral route, although parenteral and perinatal routes have been reported. HEV infection develops in most individuals as a self-limiting, acute, icteric hepatitis; with mortality rates around 1%. However, some affected individuals will develop fulminant hepatic failure, a serious condition that is frequently fatal without a liver transplant. This complication is particularly common when the infection occurs in pregnant women, where mortality rates rise dramatically to up to 25%. Among the preventive measures available to avoid HEV infection, two separate subunit vaccines containing recombinant truncated capsid proteins of HEV have been shown to be highly effective in the prevention of disease. One of them, HEV 239, was approved in China, and its commercialization by Innovax began in November 2012 under the name Hecolin(®). PMID:26355220

  1. Current Knowledge on Hepatitis E

    PubMed Central

    Pérez-Gracia, María Teresa; García, Mario; Suay, Beatriz; Mateos-Lindemann, María Luisa

    2015-01-01

    Although only a single serotype of hepatitis E virus (HEV), the causative agent of hepatitis E, has been identified, there is great genetic variation among the different HEV isolates reported. There are at least four major recognized genotypes of HEV: genotypes 1 and 2 are mainly restricted to humans and linked to epidemic outbreaks in nonindustrialized countries, whereas genotypes 3 and 4 are zoonotic in both developing and industrialized countries. Besides human strains, genotype 3 and 4 strains of HEV have been genetically characterized from swine, sika deer, mongooses, sheep, and rabbits. Currently, there are approximately 11,000 human and animal sequences of HEV available at the International Nucleotide Sequence Database Collaboration. HEV is the major cause of waterborne outbreaks of hepatitis in areas of poor sanitation. Additionally, it is responsible for sporadic cases of viral hepatitis in not only endemic but industrialized countries as well. Transmission of HEV occurs predominantly by the fecal-oral route, although parenteral and perinatal routes have been reported. HEV infection develops in most individuals as a self-limiting, acute, icteric hepatitis; with mortality rates around 1%. However, some affected individuals will develop fulminant hepatic failure, a serious condition that is frequently fatal without a liver transplant. This complication is particularly common when the infection occurs in pregnant women, where mortality rates rise dramatically to up to 25%. Among the preventive measures available to avoid HEV infection, two separate subunit vaccines containing recombinant truncated capsid proteins of HEV have been shown to be highly effective in the prevention of disease. One of them, HEV 239, was approved in China, and its commercialization by Innovax began in November 2012 under the name Hecolin®. PMID:26355220

  2. Frontotemporal lobar degeneration: current perspectives

    PubMed Central

    Riedl, Lina; Mackenzie, Ian R; Förstl, Hans; Kurz, Alexander; Diehl-Schmid, Janine

    2014-01-01

    The term frontotemporal lobar degeneration (FTLD) refers to a group of progressive brain diseases, which preferentially involve the frontal and temporal lobes. Depending on the primary site of atrophy, the clinical manifestation is dominated by behavior alterations or impairment of language. The onset of symptoms usually occurs before the age of 60 years, and the mean survival from diagnosis varies between 3 and 10 years. The prevalence is estimated at 15 per 100,000 in the population aged between 45 and 65 years, which is similar to the prevalence of Alzheimer’s disease in this age group. There are two major clinical subtypes, behavioral-variant frontotemporal dementia and primary progressive aphasia. The neuropathology underlying the clinical syndromes is also heterogeneous. A common feature is the accumulation of certain neuronal proteins. Of these, the microtubule-associated protein tau (MAPT), the transactive response DNA-binding protein, and the fused in sarcoma protein are most important. Approximately 10% to 30% of FTLD shows an autosomal dominant pattern of inheritance, with mutations in the genes for MAPT, progranulin (GRN), and in the chromosome 9 open reading frame 72 (C9orf72) accounting for more than 80% of familial cases. Although significant advances have been made in recent years regarding diagnostic criteria, clinical assessment instruments, neuropsychological tests, cerebrospinal fluid biomarkers, and brain imaging techniques, the clinical diagnosis remains a challenge. To date, there is no specific pharmacological treatment for FTLD. Some evidence has been provided for serotonin reuptake inhibitors to reduce behavioral disturbances. No large-scale or high-quality studies have been conducted to determine the efficacy of non-pharmacological treatment approaches in FTLD. In view of the limited treatment options, caregiver education and support is currently the most important component of the clinical management. PMID:24600223

  3. Attention deficit disorder: current perspectives.

    PubMed

    Shaywitz, S E; Shaywitz, B A

    1987-01-01

    This review focuses on selected issues in the rapidly proliferating scientific literature on attention deficit disorder (ADD). It encompasses a brief overview of ADD, including a review of the historical trends, causation, and a description of the clinical characteristics. Critical issues fundamental to understanding of ADD are addressed next. Evidence is presented to suggest that there are several groups of children with ADD who are currently under-identified and therefore, underserved (girls with ADD; ADD without hyperactivity). The concept is introduced of uncomplicated ADD and ADD-Plus (ADD-P), a term used to designate ADD associated with other complicating features such as conduct disorder. Specific methodologic issues and their relationship to the under-identification of these groups of children follows. This discussion encompasses the reasons for diagnostic imprecision and inconsistency, emphasizing the problem of selective referral patterns and how it results in an inaccurate portrait of ADD. We then present new approaches to the definition and diagnosis of ADD based on empiric studies designed to circumvent some of these problems. We conclude with a summary of the implications of these findings, and recommendations for public policy in ADD, particularly the need to recognize that ADD may occur even in the most intellectually gifted individuals and even in students in select colleges. Often these children with the highest potential are penalized most, not because of conceptual limitations or because they do not understand, but because educators often fail to recognize the symptom complex. Many of these children are succeeding through intelligence and great effort, but many more could succeed with proper identification. PMID:3334012

  4. Apparatus for measuring high frequency currents

    NASA Technical Reports Server (NTRS)

    Hagmann, Mark J. (Inventor); Sutton, John F. (Inventor)

    2003-01-01

    An apparatus for measuring high frequency currents includes a non-ferrous core current probe that is coupled to a wide-band transimpedance amplifier. The current probe has a secondary winding with a winding resistance that is substantially smaller than the reactance of the winding. The sensitivity of the current probe is substantially flat over a wide band of frequencies. The apparatus is particularly useful for measuring exposure of humans to radio frequency currents.

  5. [Current status of autism studies].

    PubMed

    Kurita, H

    2001-01-01

    The current status of autism studies was reviewed based on English articles published during the 1990s. Although the concepts of autism and pervasive developmental disorders (PDD) are established, diagnostic criteria of PDDNOS or atypical autism, which is frequently difficult to differentiate from autism, need to be established. The prevalence of autism has been estimated as about 0.05% in the U.S and many European countries, while it was reported to be 0.1% or higher in Japan and some European countries, though the reasons for this difference are unclear. High-functioning (IQ > or = 70) autism may not be as rare a condition as previously thought and both its difference from and similarity to Asperger's syndrome, the highest functioning PDD subtype, need clarification. About 20 to 40% of children with autism lose meaningful words by the age of 2 years and display autistic symptoms thereafter. Such autism, called the setback type in Japan, has been demonstrated to have a poorer adolescent/adult outcome compared to autism without setback and its relationship with childhood disintegrative disorder, which displays a clearer regression after normal development for at least the first 2 years of life, needs to be addressed. The etiology of autism is now considered mostly genetic for reasons, such as the significantly higher concordance rate of autism in identical twin pairs (60-80%) than in fraternal twin pairs (0-10%) and an 3-5% incidence of autism among sibs of an autism proband, 30 to 100 times higher than that in the general population. The involvement of several genes is implicated to create susceptibility for autism, yet the responsible genes have not been identified. Although there is no medication to cure autism, some psychotropic drugs, such as antipsychotics and SSRIs, seem effective for behavior problems in autism patients. Psychosocial treatments are the main therapeutic approach to autism, though they are yet to be well systematized. It is important to

  6. Current COIL research in Samara

    NASA Astrophysics Data System (ADS)

    Nikolaev, Valeri D.

    1996-02-01

    Development of the high pressure singlet oxygen generator (SOG) is a very important aspect for chemical oxygen-iodine laser (COIL). Increasing of oxygen pressure up to 30 torr and more at conserving high O2(1(Delta) ) yield and maintaining BHP temperature at minus (10 divided by 20) degrees Celsius permits us to decrease ration [H2O]/[O2] to 5% and less. In this case COIL can operate successfully without a water vapor trap. With raising the total pressure Reynolds number increases too, diminishing boundary layers in supersonic nozzles and improving pressure recovery. The weight and dimensions of the SOG and laser become reduced for the same gas flow rate. For solving these problems the jet SOG has been suggested and developed in Lebedev Physical Institute, Samara Branch. The advantages of the jet SOG consist of the following: (1) Large and controlled specific surface of contact liquid-gas provides for high mass transfer efficiency. (2) High jets velocity guarantees fast basic hydrogen peroxide (BHP) surface renovation. (3) High gas velocity in the reaction zone diminishes O2(1(Delta) ) quenching. (4) Efficient gas-liquid heat exchange eliminates the gas heating and generation water vapor due O2(1(Delta) ) quenching. (5) Counterflowing design of the jet SOG produces the best conditions for self-cleaning gas flow of droplets in the reaction zone and gives the possibility of COIL operation without droplets separator. High pressure jet SOG has some features connected with intrachannel jet formation, free space jets reconstruction, interaction jets ensemble with counter moving gas flow and drag part of gas by jets, disintegrating jets, generation and separation of droplets, heat effects, surface renovation, impoverishment BHP surface by HO2- ions, moving solution film on the reaction zone walls, etc. In this communication our current understanding of the major processes in the jet SOG is set forth. The complex gas and hydrodynamic processes with heat and mass transfer

  7. rasdaman Array Database: current status

    NASA Astrophysics Data System (ADS)

    Merticariu, George; Toader, Alexandru

    2015-04-01

    rasdaman (Raster Data Manager) is a Free Open Source Array Database Management System which provides functionality for storing and processing massive amounts of raster data in the form of multidimensional arrays. The user can access, process and delete the data using SQL. The key features of rasdaman are: flexibility (datasets of any dimensionality can be processed with the help of SQL queries), scalability (rasdaman's distributed architecture enables it to seamlessly run on cloud infrastructures while offering an increase in performance with the increase of computation resources), performance (real-time access, processing, mixing and filtering of arrays of any dimensionality) and reliability (legacy communication protocol replaced with a new one based on cutting edge technology - Google Protocol Buffers and ZeroMQ). Among the data with which the system works, we can count 1D time series, 2D remote sensing imagery, 3D image time series, 3D geophysical data, and 4D atmospheric and climate data. Most of these representations cannot be stored only in the form of raw arrays, as the location information of the contents is also important for having a correct geoposition on Earth. This is defined by ISO 19123 as coverage data. rasdaman provides coverage data support through the Petascope service. Extensions were added on top of rasdaman in order to provide support for the Geoscience community. The following OGC standards are currently supported: Web Map Service (WMS), Web Coverage Service (WCS), and Web Coverage Processing Service (WCPS). The Web Map Service is an extension which provides zoom and pan navigation over images provided by a map server. Starting with version 9.1, rasdaman supports WMS version 1.3. The Web Coverage Service provides capabilities for downloading multi-dimensional coverage data. Support is also provided for several extensions of this service: Subsetting Extension, Scaling Extension, and, starting with version 9.1, Transaction Extension, which

  8. Current Concepts of Maternal Nutrition

    PubMed Central

    Lowensohn, Richard I.; Stadler, Diane D.; Naze, Christie

    2016-01-01

    Background A nutrient-rich maternal diet before and during pregnancy is associated with improved fetal health, more appropriate birth weight, and increased rates of maternal and infant survival. Physicians need a better understanding of the role of diet in shaping fetal outcomes. Given this background, we reviewed and summarized articles on maternal nutrition found in MEDLINE since 1981, written in English, and limited to human subjects. For the Offspring Maternal diets high in sugar and fat lead to an increased incidence of metabolic syndrome, diabetes, and cardiovascular disease later in life. Folic acid should be supplemented prior to conception and continued through at least the first 28 days of fetal life to prevent neural tube defects, and vitamin C should be given to women who smoke to lower the incidence of asthma and wheezing in the children. Iodine deficiency is increasing, and iodine should be included in prenatal supplements. If the maternal hemoglobin is 7 g/dL or more, there is no evidence that iron supplementation is needed. Fish intake during pregnancy is protective against atopic outcomes, whereas high-meat diets contribute to elevated adult blood pressure and hypersecretion of cortisol. For the Mother Calcium supplementation lowers the risk of preeclampsia and hypertensive disease in pregnancy. Conclusions Given the limits of our current knowledge, a diet rich in whole grains, fruits, vegetables, and selected fish is desirable for the best outcomes. Diets high in sugar and fat lead to higher rates of diabetes, metabolic syndrome, and cardiovascular disease. Folic acid, iodine, and calcium in all pregnant women and vitamin C in smokers are the only supplements so far shown to be of value for routine use. The physician treating a pregnant woman should be ready to advise a healthy diet for the benefit of the fetus. Target Audience Obstetricians and gynecologists, family physicians Learning Objectives After participating in this activity, the

  9. Dark current behavior in DSLR cameras

    NASA Astrophysics Data System (ADS)

    Dunlap, Justin C.; Sostin, Oleg; Widenhorn, Ralf; Bodegom, Erik

    2009-02-01

    Digital single-lens reflex (DSLR) cameras are examined and their dark current behavior is presented. We examine the influence of varying temperature, exposure time, and gain setting on dark current. Dark current behavior unique to sensors within such cameras is observed. In particular, heat is trapped within the camera body resulting in higher internal temperatures and an increase in dark current after successive images. We look at the possibility of correcting for the dark current, based on previous work done for scientific grade imagers, where hot pixels are used as indicators for the entire chip's dark current behavior. Standard methods of dark current correction are compared to computed dark frames. Dark current is a concern for DSLR cameras as optimum conditions for limiting dark current, such as cooling the imager, are not easily obtained in the typical use of such imagers.

  10. Current trends in breast reduction.

    PubMed

    Roje, Zdravko; Roje, Zeljka; Milosević, Milan; Varvodić, Josip; Mance, Marko

    2012-06-01

    Results of our study describe the long term effects of reduction mammaplasty. Many women with excessively small or large breasts have an altered personal self-image and often suffer from low self-esteem and other psychological stresses. This procedure is designed to reduce and reshape large breasts, and since the size, shape, and symmetry of a woman's breasts can have a profound effect on her mental and physical well-being it is important to observe the patient's long-term outcome. Currently, breast reduction surgery is safe, effective and beneficial to the patient. In Croatia, reduction mammoplasty is often excluded from the general health care plan. The distinction between "reconstructive" versus "cosmetic" breast surgery is very well defined by the American Society of Plastic Surgeons Board of Directors. Unfortunately, the Croatian Health Society has yet to standardize such a distinction. There is an imperative need for evidence-based selection criteria. We retrospectively analyzed data of 59 female patients suffering from symptomatic macromastia who underwent reduction mammaplasty over a 16 year period (1995 until 2011). Our aim was to compare and contrast the various techniques available for reduction mammaplasty and to determine, based on patient outcome and satisfaction, which technique is most suited for each patient. The results of our study generally reinforce the observation that reduction mammaplasty significantly provides improvements in health status, long-term quality of life, postsurgical breast appearance and significantly decrease physical symptoms of pain. A number of 59 consecutive cases were initially treated with the four different breast reduction techniques: inverted-T scat or Wisa pattern breast reduction, vertical reduction mammaplasty, simplified vertical reduction mammaplasty, inferior pedicle and free nipple graft techniques. The average clinical follow-up period was 6-months, and included 48 patients. The statistical analysis of the

  11. Tokamak Equilibria with Reversed Current Density

    NASA Astrophysics Data System (ADS)

    Martynov, A. A.; Medvedev, S. Yu.; Villard, L.

    2003-08-01

    Observations of nearly zero toroidal current in the central region of tokamaks (the “current hole”) raises the question of the existence of toroidal equilibria with very low or reversed current in the core. The solutions of the Grad-Shafranov equilibrium equation with hollow toroidal current density profile including negative current density in the plasma center are investigated. Solutions of the corresponding eigenvalue problem provide simple examples of such equilibrium configurations. More realistic equilibria with toroidal current density reversal are computed using a new equilibrium problem formu­lation and computational algorithm which do not assume nested magnetic surfaces.

  12. ELECTROMIGRATION ISSUES IN HIGH CURRENT HORN.

    SciTech Connect

    ZHANG, S.Y.; BELLAVIA, S.; SANDBERG, J.; ET AL.

    2005-05-16

    The secondary particle focusing horn for the AGS neutrino experiment proposal is a high current and high current density device. The peak current of horn is 300 kA. At the smallest area of horn, the current density is near 8 kA/mm{sup 2}. At very high current density, a few kA/mm{sup 2}, the electromigration phenomena will occur. Momentum transfer between electrons and metal atoms at high current density causes electromigration. The reliability and lifetime of focusing horn can be severely reduced by electromigration. In this paper, we discuss issues such as device reliability model, incubation time of electromigration, and lifetime of horn.

  13. Thermoelectric converters for alternating current standards

    NASA Astrophysics Data System (ADS)

    Anatychuk, L. I.; Taschuk, D. D.

    2012-06-01

    Thermoelectric converters of alternating current remain priority instruments when creating standard equipment. This work presents the results of design and manufacture of alternating current converter for a military standard of alternating current in Ukraine. Results of simulation of temperature distribution in converter elements, ways of optimization to improve the accuracy of alternating current signal reproduction are presented. Results of metrological trials are given. The quality of thermoelectric material specially created for alternating current metrology is verified. The converter was used in alternating current standard for the frequency range from 10 Hz to 30 MHz. The efficiency of using thermoelectric signal converters in measuring instruments is confirmed.

  14. Defining and Resolving Current Systems in Geospace

    NASA Astrophysics Data System (ADS)

    Liemohn, Michael; Ganushkina, Natalia; Amariutei, Olga; Daglis, Yannis; Dandouras, Iannis; De Zeeuw, Darren; Dubyagin, Stepan; Ebihara, Yusuke; Ilie, Raluca; Katus, Roxanne; Kubyshkina, Marina; Milan, Steve; Ohtani, Shin; Ostgaard, Nikolai; Reistad, Jone; Toffoletto, Frank; Zaharia, Sorin

    2013-04-01

    Electric currents flowing through geospace support a highly nondipolar magnetic field topology, and their time-varying dynamics change particle drift paths and create a nonlinear feedback on the currents themselves. A number of current systems exist in the magnetosphere, most commonly the dayside magnetopause Chapman-Ferraro currents, high latitude "region 1" field-aligned Birkeland currents, lower-latitude "region 2" field-aligned currents connected to the partial ring current, magnetotail currents, and the symmetric ring current. In the near-Earth nightside, however, several of these current systems flow in close proximity to each other and it is very difficult to identify a local measurement as belonging to a specific system. Such identification is important, however, because how the current closes and how these loops change in space and time governs the magnetic topology of the magnetosphere and therefore controls the physical processes of geospace. Furthermore, many methods exist for identifying the regions of near-Earth space carrying each type of current. This study presents a robust collection of these definitions of current systems in geospace, particularly in the near-Earth nightside magnetosphere, as viewed from a variety of observational and computational analysis techniques. The influence of definitional choice on the resulting interpretation of physical processes governing geospace dynamics is presented and discussed.

  15. A Current Perspective on Photocatalysis

    SciTech Connect

    Fujita, E.; Muckerman, J.T.; Domen, K.

    2011-02-18

    The efficient conversion of solar photons into solar electricity and solar fuels is one of the most important scientific challenges of this century owing to dwindling fossil fuel reserves and the need for clean energy. While research in the direct conversion of solar energy to electricity in the areas of low-cost photovoltaic (PV) systems based on all-inorganic semiconductors, dye-sensitized solar cells, organic, and molecular PV is more technically advanced than its direct conversion to fuels, electricity may not be the ultimate primary solar energy conversion choice owing to the intermittence of solar radiation, the considerable energy loss during transmission, the availability of cost-effective storage media for electricity, and the continuing need for liquid transportation fuels. On the other hand, the direct conversion of solar photons to fuels such as H{sub 2}, CO, alcohols, and hydrocarbons using H{sub 2}O and CO{sub 2} as feedstocks offers a solution for the storage and distribution of solar energy in the form of stable chemical bonds that can be activated to provide energy at arbitrary times and locations. The latter approach to photocatalysis is generally called artificial photosynthesis, and has received renewed interest over the past five or so years. While 'photocatalysis' has not traditionally been restricted to the generation of 'solar fuels,' and has included the production of other useful chemicals, polymerization, and environmental remediation applications, the recent upsurge of interest has been driven mostly by renewable energy issues. It was the pioneering work on photo-electrochemical splitting of water to H{sub 2} and O{sub 2} by n-type TiO{sub 2} using ultraviolet light, by Fujishima and Honda in 1972, that ushered in the area of research that has come to be known as 'solar fuels,' and that has led to the terms 'photocatalysis' and 'solar fuels' becoming almost synonymous. This special issue of ChemSusChem is devoted to providing a current

  16. Dual current readout for precision plating

    NASA Technical Reports Server (NTRS)

    Iceland, W. F.

    1970-01-01

    Bistable amplifier prevents damage in the low range circuitry of a dual scale ammeter. It senses the current and switches automatically to the high range circuitry as the current rises above a preset level.

  17. The Fluid Mechanics of Pyroclastic Density Currents

    NASA Astrophysics Data System (ADS)

    Dufek, Josef

    2016-01-01

    Pyroclastic density currents are generated in explosive volcanic eruptions when gas and particle mixtures remain denser than the surrounding atmosphere. These mobile currents have a diversity of flow regimes, from energetic granular flows to turbulent suspensions. Given their hazardous nature, much of our understanding of the internal dynamics of these currents has been explored through mathematical and computational models. This review discusses the anatomy of these currents and their phenomenology and places these observations in the context of forces driving the currents. All aspects of the current dynamics are influenced by multiphase interactions, and the study of these currents offers insight into a high-energy end-member of multiphase flow. At low concentration, momentum transfer is dominated by particle-gas drag. At higher concentration, particle collisions, friction, and gas pore pressure act to redistribute momentum. This review examines end-member theoretical models for dilute and concentrated flow and then considers insight gained from multiphase simulations of pyroclastic density currents.

  18. Modeling Harris Current Sheets with Themis Observations

    NASA Technical Reports Server (NTRS)

    Kepko, L.; Angelopoulos, V.; McPherron, R. L.; Apatenkov, S.; Glassmeier, K.-H.

    2010-01-01

    Current sheets are ubiquitous in nature. occurring in such varied locations as the solar atmosphere. the heliosphere, and the Earth's magnetosphere. The simplest current sheet is the one-dimensional Harris neutral sheet, with the lobe field strength and scale-height the only free parameters. Despite its simplicity, confirmation of the Harris sheet as a reasonable description of the Earth's current sheet has remained elusive. In early 2009 the orbits of the 5 THEMIS probes fortuitously aligned such that profiles of the Earth's current sheet could be modeled in a time dependent manner. For the few hours of alignment we have calculated the time history of the current sheet parameters (scale height and current) in the near-Earth region. during both quiet and active times. For one particular substorm. we further demonstrate good quantitative agreement with the diversion of cross tail current inferred from the Harris modeling with the ionospheric current inferred from ground magnetometer data.

  19. Neutral-current x-distributions

    DOE R&D Accomplishments Database

    Friedman, J. I.; Kendall, H. W.; Bogert, D.; Burnstein, R.; Fisk, R.; Fuess, S.; Bofill, J.; Busza, W.; Eldridge, T.; Abolins, M.; Brock, R.; et al.

    1984-06-01

    The role of the semi leptonic neutral current interaction as a probe of nucleon structure is examined. Previous measurements of neutral current x-distributions are reviewed, and new results from the Fermilab - MIT - MSU collaboration are presented.

  20. High voltage compliance constant current ballast

    NASA Technical Reports Server (NTRS)

    Rosenthal, L. A.

    1976-01-01

    A ballast circuit employing a constant current diode and a vacuum tube that can provide a constant current over a voltage range of 1000 volts. The simple circuit can prove useful in studying voltage breakdown characteristics.

  1. Three-dimensional observations of Birkeland currents

    NASA Technical Reports Server (NTRS)

    Barfield, J. N.; Saflekos, N. A.; Sheehan, R. E.; Carovillano, R. L.; Potemra, T. A.

    1986-01-01

    The dominant coupling between the ionosphere and magnetosphere is now understood to be Birkeland currents. During substorms the Birkeland current system in the midnight sector is generally interpreted as a cross-tail current interruption and diversion along magnetic field lines to the conducting ionosphere, which carries the intensified auroral electrojet. In the present study, the equatorial current diversion, the Birkeland current intensification, and the auroral electrojet increase in activity were observed to be initiated simultaneously at the onset of substorms. The principal finding is that the field-aligned currents of the components of the current wedge have been observed simultaneously on the ground, at low-altitude satellite orbits, and at geosynchronous satellite orbits. Recent dynamic modeling work by Chen et al. (1982) appears to support our findings. These observations contribute significantly toward the confirmation of the substorm current wedge model and complement and extend the results obtained by Nagai (1982).

  2. Improving Current Balance In Parallel MOSFET's

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    1992-01-01

    Simple circuit makes currents more nearly equal. Addition of diodes and adjustable-tap resistor increases operating range over which drain currents in two unmatched power MOSFET's brought more nearly into balance.

  3. [Current malaria situation in Turkmenistan].

    PubMed

    Amangel'diev, K A

    2001-01-01

    Malaria is one of the main health problems facing most developing countries having a hot climate. It is a problem in Turkmenistan. The country is situated in Central Asia, north of the Kopetdag mountains, between the Caspian Sea to the west and the Amu-Darya river to the east. Turkmenistan stretches for a distance of 1,100 km from west to east and 650 km from north to south. It borders Kazakhstan in the north, Uzbekistan in the east and north-east, Iran in the south, and Afghanistan in the south-east. Seven malaria vector species are found in Turkmenistan, the main ones being Anopheles superpictus, An. pulcherrimus, and An. martinius. The potentially endemic area consists of the floodplains of the Tejen and Murgab rivers, with a long chain of reservoirs built along them. In 1980 most cases of imported malaria were recorded in military personnel who had returned from service in Afghanistan. In the past years, only tertian (Plasmodium vivax) malaria has been recorded and there have been no death from malaria over that period. In the Serkhetabad (Gushgi) district there are currently 5 active foci of malaria infection, with a population of 22,000 people. In 1999, forty nine cases of P. vivax malaria were recorded in Turkmenistan. Of them, 36 cases, including 4 children under 14 years were diagnosed for the first time while 13 were relapses. There were 88 fewer cases than those in the previous year (by a factor of 2.8). There were 17 more cases of imported malaria than those in 1998 (by a factor of 1.7), most of which occurred in the foci of malaria infection (Serkhetabad, Tagtabazar, and Kerki districts), in the city of Ashkhabat and in Lebap, Dashkhovuz and Akhal Regions. The emergence of indigenous malaria in the border areas was due to the importation of the disease at intervals by infected mosquitoes flying in from neighbouring countries (e.g. Afghanistan), the lack of drugs to treat the first cases and the lack of alternative insecticides. Most patients suffer

  4. WORLD SURFACE CURRENTS FROM SHIP'S DRIFT OBSERVATIONS

    SciTech Connect

    Duncan, C.P.; Schladow, S.G.

    1980-11-01

    Over 4 million observations of ship's drift are on file at the U.S. National Oceanographic Data Centre, in Washington, D. C., representing a vast amount of information on ocean surface currents. The observed drift speeds are dependent on the frequency of occurence of the particular current speeds and the frequency of observation. By comparing frequency of observation with the drift speeds observed it is possible to confirm known current patterns and detect singularities in surface currents.

  5. Simple constant-current-regulated power supply

    NASA Technical Reports Server (NTRS)

    Priebe, D. H. E.; Sturman, J. C.

    1977-01-01

    Supply incorporates soft-start circuit that slowly ramps current up to set point at turn-on. Supply consists of full-wave rectifier, regulating pass transistor, current feedback circuit, and quad single-supply operational-amplifier circuit providing control. Technique is applicable to any system requiring constant dc current, such as vacuum tube equipment, heaters, or battery charges; it has been used to supply constant current for instrument calibration.

  6. Electropneumatic transducer automatically limits motor current

    NASA Technical Reports Server (NTRS)

    Lovitt, T. F.

    1966-01-01

    Pneumatic controller regulates the load on a centrifugal freon compressor in a water cooling system, thus limiting the current input to an electric motor driving it. An electromechanical transducer monitoring the motor input current sends out air signals which indicate changes in the current to the pneumatic controller.

  7. 45 CFR 1100.4 - Current index.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Current index. 1100.4 Section 1100.4 Public... INFORMATION § 1100.4 Current index. Each agency shall maintain and make available for public inspection and copying a current index providing identifying information for the public as to any matter which is...

  8. 12 CFR 1402.11 - Current index.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Current index. 1402.11 Section 1402.11 Banks... the Farm Credit System Insurance Corporation § 1402.11 Current index. The Farm Credit System Insurance Corporation will make available for public inspection and copying a current index to provide...

  9. 49 CFR 193.2633 - Interference currents.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Interference currents. 193.2633 Section 193.2633...: FEDERAL SAFETY STANDARDS Maintenance § 193.2633 Interference currents. (a) Each component that is subject to electrical current interference must be protected by a continuing program to minimize...

  10. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Current, leakage. A stray electric current of relatively small value which flows through or across...

  11. 22 CFR 212.23 - Current index.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Current index. 212.23 Section 212.23 Foreign... Inspection and Copying § 212.23 Current index. USAID maintains and makes available for public inspection and copying a current index providing identifying information for the public as to any matter which has...

  12. 45 CFR 502.6 - Current index.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Current index. 502.6 Section 502.6 Public Welfare..., DEPARTMENT OF JUSTICE RULES OF PRACTICE PUBLIC INFORMATION-FREEDOM OF INFORMATION ACT § 502.6 Current index. The Commission will maintain and make available for public inspection and copying, current...

  13. 45 CFR 502.6 - Current index.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 3 2013-10-01 2013-10-01 false Current index. 502.6 Section 502.6 Public Welfare..., DEPARTMENT OF JUSTICE RULES OF PRACTICE PUBLIC INFORMATION-FREEDOM OF INFORMATION ACT § 502.6 Current index. The Commission will maintain and make available for public inspection and copying, current...

  14. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Current, leakage. A stray electric current of relatively small value which flows through or across...

  15. 49 CFR 236.733 - Current, foreign.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Current, foreign. 236.733 Section 236.733 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Current, foreign. A term applied to stray electric currents which may affect a signaling system, but...

  16. 12 CFR 1402.11 - Current index.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Current index. 1402.11 Section 1402.11 Banks... the Farm Credit System Insurance Corporation § 1402.11 Current index. The Farm Credit System Insurance Corporation will make available for public inspection and copying a current index to provide...

  17. 49 CFR 236.733 - Current, foreign.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Current, foreign. 236.733 Section 236.733 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Current, foreign. A term applied to stray electric currents which may affect a signaling system, but...

  18. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Current, leakage. A stray electric current of relatively small value which flows through or across...

  19. 12 CFR 1402.11 - Current index.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Current index. 1402.11 Section 1402.11 Banks... the Farm Credit System Insurance Corporation § 1402.11 Current index. The Farm Credit System Insurance Corporation will make available for public inspection and copying a current index to provide...

  20. 49 CFR 193.2633 - Interference currents.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Interference currents. 193.2633 Section 193.2633...: FEDERAL SAFETY STANDARDS Maintenance § 193.2633 Interference currents. (a) Each component that is subject to electrical current interference must be protected by a continuing program to minimize...

  1. 14 CFR 21.493 - Current records.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Current records. 21.493 Section 21.493... PROCEDURES FOR PRODUCTS AND PARTS Designated Alteration Station Authorization Procedures § 21.493 Current records. (a) The DAS shall maintain, at its facility, current records containing— (1) For each product...

  2. 14 CFR 21.293 - Current records.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Current records. 21.293 Section 21.293... PROCEDURES FOR PRODUCTS AND PARTS Delegation Option Authorization Procedures § 21.293 Current records. Link... certificated under a delegation option authorization, current records containing the following: (1) For...

  3. 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.

  4. 49 CFR 236.733 - Current, foreign.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Current, foreign. 236.733 Section 236.733 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Current, foreign. A term applied to stray electric currents which may affect a signaling system, but...

  5. 49 CFR 236.733 - Current, foreign.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Current, foreign. 236.733 Section 236.733 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Current, foreign. A term applied to stray electric currents which may affect a signaling system, but...

  6. 22 CFR 212.23 - Current index.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Current index. 212.23 Section 212.23 Foreign... Inspection and Copying § 212.23 Current index. USAID maintains and makes available for public inspection and copying a current index providing identifying information for the public as to any matter which has...

  7. Expert system for analyzing eddy current measurements

    DOEpatents

    Levy, Arthur J.; Oppenlander, Jane E.; Brudnoy, David M.; Englund, James M.; Loomis, Kent C.

    1994-01-01

    A method and apparatus (called DODGER) analyzes eddy current data for heat exchanger tubes or any other metallic object. DODGER uses an expert system to analyze eddy current data by reasoning with uncertainty and pattern recognition. The expert system permits DODGER to analyze eddy current data intelligently, and obviate operator uncertainty by analyzing the data in a uniform and consistent manner.

  8. 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).

  9. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Current, leakage. A stray electric current of relatively small value which flows through or across...

  10. 14 CFR 21.493 - Current records.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Current records. 21.493 Section 21.493... PROCEDURES FOR PRODUCTS AND PARTS Designated Alteration Station Authorization Procedures § 21.493 Current records. (a) The DAS shall maintain, at its facility, current records containing— (1) For each product...

  11. 49 CFR 193.2633 - Interference currents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Interference currents. 193.2633 Section 193.2633...: FEDERAL SAFETY STANDARDS Maintenance § 193.2633 Interference currents. (a) Each component that is subject to electrical current interference must be protected by a continuing program to minimize...

  12. 45 CFR 1100.4 - Current index.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 3 2012-10-01 2012-10-01 false Current index. 1100.4 Section 1100.4 Public... INFORMATION § 1100.4 Current index. Each agency shall maintain and make available for public inspection and copying a current index providing identifying information for the public as to any matter which is...

  13. 22 CFR 212.23 - Current index.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Current index. 212.23 Section 212.23 Foreign... Inspection and Copying § 212.23 Current index. USAID maintains and makes available for public inspection and copying a current index providing identifying information for the public as to any matter which has...

  14. 45 CFR 1100.4 - Current index.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 3 2011-10-01 2011-10-01 false Current index. 1100.4 Section 1100.4 Public... INFORMATION § 1100.4 Current index. Each agency shall maintain and make available for public inspection and copying a current index providing identifying information for the public as to any matter which is...

  15. 45 CFR 502.6 - Current index.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 3 2012-10-01 2012-10-01 false Current index. 502.6 Section 502.6 Public Welfare..., DEPARTMENT OF JUSTICE RULES OF PRACTICE PUBLIC INFORMATION-FREEDOM OF INFORMATION ACT § 502.6 Current index. The Commission will maintain and make available for public inspection and copying, current...

  16. 12 CFR 1402.11 - Current index.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Current index. 1402.11 Section 1402.11 Banks... the Farm Credit System Insurance Corporation § 1402.11 Current index. The Farm Credit System Insurance Corporation will make available for public inspection and copying a current index to provide...

  17. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Current, leakage. A stray electric current of relatively small value which flows through or across...

  18. 45 CFR 1100.4 - Current index.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 3 2014-10-01 2014-10-01 false Current index. 1100.4 Section 1100.4 Public... INFORMATION § 1100.4 Current index. The National Endowment for the Arts shall maintain and make available for public inspection and copying a current index providing identifying information for the public as to...

  19. 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.

  20. 49 CFR 236.733 - Current, foreign.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Current, foreign. 236.733 Section 236.733 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Current, foreign. A term applied to stray electric currents which may affect a signaling system, but...

  1. 22 CFR 212.23 - Current index.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Current index. 212.23 Section 212.23 Foreign... Inspection and Copying § 212.23 Current index. USAID maintains and makes available for public inspection and copying a current index providing identifying information for the public as to any matter which has...

  2. 45 CFR 1100.4 - Current index.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 3 2013-10-01 2013-10-01 false Current index. 1100.4 Section 1100.4 Public... INFORMATION § 1100.4 Current index. Each agency shall maintain and make available for public inspection and copying a current index providing identifying information for the public as to any matter which is...

  3. 12 CFR 1402.11 - Current index.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Current index. 1402.11 Section 1402.11 Banks... the Farm Credit System Insurance Corporation § 1402.11 Current index. The Farm Credit System Insurance Corporation will make available for public inspection and copying a current index to provide...

  4. 49 CFR 193.2633 - Interference currents.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Interference currents. 193.2633 Section 193.2633...: FEDERAL SAFETY STANDARDS Maintenance § 193.2633 Interference currents. (a) Each component that is subject to electrical current interference must be protected by a continuing program to minimize...

  5. 49 CFR 193.2633 - Interference currents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Interference currents. 193.2633 Section 193.2633...: FEDERAL SAFETY STANDARDS Maintenance § 193.2633 Interference currents. (a) Each component that is subject to electrical current interference must be protected by a continuing program to minimize...

  6. 45 CFR 502.6 - Current index.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 3 2014-10-01 2014-10-01 false Current index. 502.6 Section 502.6 Public Welfare..., DEPARTMENT OF JUSTICE RULES OF PRACTICE PUBLIC INFORMATION-FREEDOM OF INFORMATION ACT § 502.6 Current index. The Commission will maintain and make available for public inspection and copying, current...

  7. 45 CFR 502.6 - Current index.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 3 2011-10-01 2011-10-01 false Current index. 502.6 Section 502.6 Public Welfare..., DEPARTMENT OF JUSTICE RULES OF PRACTICE PUBLIC INFORMATION-FREEDOM OF INFORMATION ACT § 502.6 Current index. The Commission will maintain and make available for public inspection and copying, current...

  8. 22 CFR 212.23 - Current index.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Current index. 212.23 Section 212.23 Foreign... Inspection and Copying § 212.23 Current index. USAID maintains and makes available for public inspection and copying a current index providing identifying information for the public as to any matter which has...

  9. Expert system for analyzing eddy current measurements

    SciTech Connect

    Levy, A.J.; Oppenlander, J.E.; Brudnoy, D.M.; Englund, J.M.; Loomis, K.C.

    1994-08-16

    A method and apparatus (called DODGER) analyzes eddy current data for heat exchanger tubes or any other metallic object. DODGER uses an expert system to analyze eddy current data by reasoning with uncertainty and pattern recognition. The expert system permits DODGER to analyze eddy current data intelligently, and obviate operator uncertainty by analyzing the data in a uniform and consistent manner. 21 figs.

  10. Aquantis Ocean Current Turbine Development Project Report

    SciTech Connect

    Fleming, Alex J.

    2014-08-23

    The Aquantis® Current Plane (“C-Plane”) technology developed by Dehlsen Associates, LLC (DA) and Aquantis, Inc. is an ocean current turbine designed to extract kinetic energy from ocean currents. The technology is capable of achieving competitively priced base-load, continuous, and reliable power generation from a source of renewable energy not before possible in this scale or form.

  11. In-line beam current monitor

    NASA Astrophysics Data System (ADS)

    Ekdahl, C. A., Jr.; Frost, C. A.

    1984-11-01

    An intense relativistic electron beam current monitor for a gas neutralized beam transport line includes a first foil for conducting plasma current to the wall where it is measured as it traverses an inductive loop formed by a cavity in the wall. An insulator foil separates the first foil from a second conducting foil which returns the current to the plasma environment.

  12. Toward Superconducting Critical Current by Design.

    PubMed

    Sadovskyy, Ivan A; Jia, Ying; Leroux, Maxime; Kwon, Jihwan; Hu, Hefei; Fang, Lei; Chaparro, Carlos; Zhu, Shaofei; Welp, Ulrich; Zuo, Jian-Min; Zhang, Yifei; Nakasaki, Ryusuke; Selvamanickam, Venkat; Crabtree, George W; Koshelev, Alexei E; Glatz, Andreas; Kwok, Wai-Kwong

    2016-06-01

    A new critical-current-by-design paradigm is presented. It aims at predicting the optimal defect landscape in superconductors for targeted applications by elucidating the vortex dynamics responsible for the bulk critical current. To this end, critical current measurements on commercial high-temperature superconductors are combined with large-scale time-dependent Ginzburg-Landau simulations of vortex dynamics. PMID:27030115

  13. The Current Status of STEM Education Research

    ERIC Educational Resources Information Center

    Brown, Josh

    2012-01-01

    This paper explores the current Science, Technology, Engineering and Mathematics (STEM) education research base through an analysis of articles from eight journals focused on the STEM disciplines. Analyzed are both practitioner and research publications to determine the current scope of STEM education research, where current STEM education…

  14. In-line beam current monitor

    DOEpatents

    Ekdahl, Jr., Carl A.; Frost, Charles A.

    1986-01-01

    An intense relativistic electron beam current monitor for a gas neutralized beam transport line includes a first foil for conducting plasma current to the wall where it is measured as it traverses an inductive loop formed by a cavity in the wall. An insulator foil separates the first foil from a second conducting foil which returns the current to the plasma environment.

  15. In-line beam current monitor

    DOEpatents

    Ekdahl, C.A. Jr.; Frost, C.A.

    1984-11-13

    An intense relativistic electron beam current monitor for a gas neutralized beam transport line includes a first foil for conducting plasma current to the wall where it is measured as it traverses an inductive loop formed by a cavity in the wall. An insulator foil separates the first foil from a second conducting foil which returns the current to the plasma environment.

  16. Circuit Controls Turn-On Current

    NASA Technical Reports Server (NTRS)

    Holmes, K. G.

    1972-01-01

    Single choke used in primary circuit with diode arrangement, maintaining dc current flow through choke and setting up a unidirectional magnetic field, limits turn-on current of transformer-rectifier power supply. Technique reduces number and weight of components and minimizes effect of initial inrush surge current on source.

  17. Ohm's law for a current sheet

    NASA Technical Reports Server (NTRS)

    Lyons, L. R.; Speiser, T. W.

    1985-01-01

    The paper derives an Ohm's law for single-particle motion in a current sheet, where the magnetic field reverses in direction across the sheet. The result is considerably different from the resistive Ohm's law often used in MHD studies of the geomagnetic tail. Single-particle analysis is extended to obtain a self-consistency relation for a current sheet which agrees with previous results. The results are applicable to the concept of reconnection in that the electric field parallel to the current is obtained for a one-dimensional current sheet with constant normal magnetic field. Dissipated energy goes directly into accelerating particles within the current sheet.

  18. The universal definition of spin current.

    PubMed

    An, Z; Liu, F Q; Lin, Y; Liu, C

    2012-01-01

    The spin current, orbit angular momentum current and total angular momentum current in a tensor form have been universally defined according to the quantum electrodynamics. Their conservation quantities and the continuity equations have been discussed in different cases. Non-relativistic approximation forms are deduced in order to explain their physical meanings, and to analyze some experimental results. The spin current of helical edge states in HgTe/CdTe quantum wells is calculated to demonstrate the properties of the spin current of the two dimensional quantum spin-Hall system. A generalized spin-orbit coupling term in the semiconducting media is deduced based on the theory of the electrodynamics in the moving media. It is recommended to use the effective total angular momentum current instead of the pure spin current to describe the distribution of polarization and the transport properties in spintronics. PMID:22563522

  19. The universal definition of spin current

    NASA Astrophysics Data System (ADS)

    An, Z.; Liu, F. Q.; Lin, Y.; Liu, C.

    2012-05-01

    The spin current, orbit angular momentum current and total angular momentum current in a tensor form have been universally defined according to the quantum electrodynamics. Their conservation quantities and the continuity equations have been discussed in different cases. Non-relativistic approximation forms are deduced in order to explain their physical meanings, and to analyze some experimental results. The spin current of helical edge states in HgTe/CdTe quantum wells is calculated to demonstrate the properties of the spin current of the two dimensional quantum spin-Hall system. A generalized spin-orbit coupling term in the semiconducting media is deduced based on the theory of the electrodynamics in the moving media. It is recommended to use the effective total angular momentum current instead of the pure spin current to describe the distribution of polarization and the transport properties in spintronics.

  20. The universal definition of spin current

    PubMed Central

    An, Z.; Liu, F. Q.; Lin, Y.; Liu, C.

    2012-01-01

    The spin current, orbit angular momentum current and total angular momentum current in a tensor form have been universally defined according to the quantum electrodynamics. Their conservation quantities and the continuity equations have been discussed in different cases. Non-relativistic approximation forms are deduced in order to explain their physical meanings, and to analyze some experimental results. The spin current of helical edge states in HgTe/CdTe quantum wells is calculated to demonstrate the properties of the spin current of the two dimensional quantum spin-Hall system. A generalized spin-orbit coupling term in the semiconducting media is deduced based on the theory of the electrodynamics in the moving media. It is recommended to use the effective total angular momentum current instead of the pure spin current to describe the distribution of polarization and the transport properties in spintronics. PMID:22563522

  1. Observation of non-classical radial current diffusion in a fully bootstrap current driven tokamak

    SciTech Connect

    Hwang, Y.S.; Forest, C.B.; Ono, M.

    1996-02-01

    Reconstruction and modeling of the plasma current profiles in a fully pressure-driven tokamak have been performed in the Current Drive Experiment-Upgrade (CDX-U). The reconstructed experimental current profile has a significant deviation from that of the calculated neoclassical currents. Satisfactory agreement between the measured and calculated model profiles was obtained by including a helicity conserving current diffusion term in the modeling which created the required self-generated `seed` current.

  2. Toroidal current asymmetry in tokamak disruptions

    SciTech Connect

    Strauss, H. R.

    2014-10-15

    It was discovered on JET that disruptions were accompanied by toroidal asymmetry of the toroidal plasma current I{sub ϕ}. It was found that the toroidal current asymmetry was proportional to the vertical current moment asymmetry with positive sign for an upward vertical displacement event (VDE) and negative sign for a downward VDE. It was observed that greater displacement leads to greater measured I{sub ϕ} asymmetry. Here, it is shown that this is essentially a kinematic effect produced by a VDE interacting with three dimensional MHD perturbations. The relation of toroidal current asymmetry and vertical current moment is calculated analytically and is verified by numerical simulations. It is shown analytically that the toroidal variation of the toroidal plasma current is accompanied by an equal and opposite variation of the toroidal current flowing in a thin wall surrounding the plasma. These currents are connected by 3D halo current, which is π/2 radians out of phase with the n = 1 toroidal current variations.

  3. Topology and Stability of EMHD Current Sheets

    NASA Astrophysics Data System (ADS)

    Urrutia, J. M.; Stenzel, R. L.

    1997-11-01

    Thin current sheets (c/ω_pe < d < r_ci) are governed by electron MHD effects. Their width, stability, and current limitations are important to the magnetic reconnection problem.(J. F. Drake et al, Phys. Rev. Lett. 73), 1251 (1994); S. V. Bulanov et al, Phys. Fluids B 4, 36 (1992). Using a large laboratory plasma we generate thin current sheets by drawing pulsed currents to a sheet electrode. The space-time evolution of the current sheet is obtained from three-dimensional magnetic probe measurements and J = nabla × B / μ_0. The current sheet is guided by a uniform axial magnetic field B_0. Time variations in the current sheet, accompanied by induced return currents, propagate in the whistler mode along B_0. While force-free EMHD fields usually produce stable current sheets, on longer time scales the ion motion can lead to current disruptions.(J. M. Urrutia and R. L. Stenzel, Phys. Plasmas 4), 36 (1997). Electron compressibility (d < c/ω_ce) and the role of B0 are investigated.

  4. Structure of the Magnetotail Current Sheet

    NASA Technical Reports Server (NTRS)

    Larson, Douglas J.; Kaufmann, Richard L.

    1996-01-01

    An orbit tracing technique was used to generate current sheets for three magnetotail models. Groups of ions were followed to calculate the resulting cross-tail current. Several groups then were combined to produce a current sheet. The goal is a model in which the ions and associated electrons carry the electric current distribution needed to generate the magnetic field B in which ion orbits were traced. The region -20 R(E) less than x less than -14 R(E) in geocentric solar magnetospheric coordinates was studied. Emphasis was placed on identifying the categories of ion orbits which contribute most to the cross-tail current and on gaining physical insight into the manner by which the ions carry the observed current distribution. Ions that were trapped near z = 0, ions that magnetically mirrored throughout the current sheet, and ions that mirrored near the Earth all were needed. The current sheet structure was determined primarily by ion magnetization currents. Electrons of the observed energies carried relatively little cross-tail current in these quiet time current sheets. Distribution functions were generated and integrated to evaluate fluid parameters. An earlier model in which B depended only on z produced a consistent current sheet, but it did not provide a realistic representation of the Earth's middle magnetotail. In the present study, B changed substantially in the x and z directions but only weakly in the y direction within our region of interest. Plasmas with three characteristic particle energies were used with each of the magnetic field models. A plasma was found for each model in which the density, average energy, cross-tail current, and bulk flow velocity agreed well with satellite observations.

  5. Substorm currents in the equatorial magnetotail

    SciTech Connect

    Iijima, T.; Watanabe, M.; Potemra, T.A.; Zanetti, L.J.; Kan, J.R.; Akasofu, S.I.

    1993-10-01

    The authors have determined characteristics of magnetospheric equatorial currents during substorms from the vector magnetic field data acquired with the GOES 5 and GOES 6 satellites, separated about 1.9 hours in MLT in geosynchronous orbit. These data have been used to determine the local time (azimuthal) and radial variation of the equatorial current. The divergence of the equatorial current was computed from these variations, and systems of field-aligned currents were deduced. During the growth phase to the maximum phase of the taillike reconfiguration of the near-Earth magnetic field, a positive divergence (away from the equatorial plane) of the westward equatorial current occurs in the late evening to premidnight MLT sector, and a negative divergence (away from the equatorial plane) occurs in the late evening to premidnight MLT sector, and a negative divergence (away from the equatorial plane) occurs in the premidnight to early morning MLT sector. This flow direction pattern is the same as that of the region 2 field-aligned current system. The authors have also determined the presence of a radial current that flows toward the earth in the late evening to premidnight sector and flows away from the Earth in the midnight to morning sector. The intensity of the radial currents increases before the expansion phase. Consequently, the patterns of field-aligned currents associated with various substorm phases are the superposition of currents driven by multiple sources with different temporal variations. They have identified at least three different but related sources of field-aligned currents during the growth and expansion phases. These sources are related to the divergence of the westward flowing equatorial current and to distributions of pressure and magnetic field gradients that evolve in the magnetotail. When combined, these complicated systems support the basic region 1 to region 2 field-aligned current flow pattern. 22 refs., 12 figs., 1 tab.

  6. Structure of the Magnetotail Current Sheet

    NASA Technical Reports Server (NTRS)

    Larson, Douglas J.; Kaufmann, Richard L.

    1996-01-01

    An orbit tracing technique was used to generate current sheets for three magnetotail models. Groups of ions were followed to calculate the resulting cross-tail current. Several groups then were combined to produce a current sheet. The goal is a model in which the ions and associated electrons carry the electric current distribution needed to generate the magnetic field B in which ion orbits were traced. The region -20 R(sub E) less than x less than - 14 R(sub E) in geocentric solar magnetospheric coordinates was studied. Emphasis was placed on identifying the categories of ion orbits which contribute most to the cross-tail current and on gaining physical insight into the manner by which the ions carry the observed current distribution. Ions that were trapped near z = 0, ions that magnetically mirrored throughout the current sheet, and ions that mirrored near the Earth all were needed. The current sheet structure was determined primarily by ion magnetization currents. Electrons of the observed energies carried relatively little cross-tail current in these quiet time current sheets. Distribution functions were generated and integrated to evaluate fluid parameters. An earlier model in which B depended only on z produced a consistent current sheet, but it did not provide a realistic representation of the Earth's middle magnetotail. In the present study, B changed substantially in the x and z directions but only weakly in the y direction within our region of interest. Plasmas with three characteristic particle energies were used with each of the magnetic field models. A plasma was found for each model in which the density, average energy, cross-tail current, and bulk flow velocity agreed well with satellite observations.

  7. Upper-ocean currents around Taiwan

    NASA Astrophysics Data System (ADS)

    Liang, W.-D.; Tang, T. Y.; Yang, Y. J.; Ko, M. T.; Chuang, W.-S.

    2003-03-01

    Current velocity, measured by Shipboard Acoustic Doppler Current Profiler (Sb-ADCP) during 1991-2000, was used to study the upper-ocean (<300 m) currents around Taiwan. The collected data were debugged, calibrated, grid, and averaged to compose a three-dimensional current-velocity distribution. The validity of the composite current velocity was supported by 12 sets of moored current-velocity time series. Qualitative agreement was obtained. The moored time series also indicated that the seasonal variation of current around Taiwan was generally weak except for the shallow-water regimes. The composite and moored currents revealed a branch of the Kuroshio that intruded steadily and persistently into the South China Sea. Part of the intruded Kuroshio flowed out of the South China Sea through the northern Luzon Strait and re-united with the main stream Kuroshio. The Kuroshio had two velocity maximum cores southeast of Taiwan, but gradually combined into one as the Kuroshio flowed north. The Kuroshio was deflected by the I-Lan Ridge east of Taiwan and the zonal-running shelf break northeast of Taiwan. At the shelf break, the Kuroshio split, with one branch intruding onto the shelf. West of the Luzon Strait, the Kuroshio intruded into the South China Sea. Some water flowed northward into the Taiwan Strait and re-joined the Kuroshio. Currents in the Taiwan Strait flowed primarily in a northward direction, except for the southward current near the coast of Mainland China. North of the Taiwan Strait, a branch of the northward flow followed the northern coast of Taiwan to join the Kuroshio. The composite current varied consistently from season to season. There was generally poor correlation between currents and local winds, especially in the deep-water regime. Remote forces were important in the currents around Taiwan.

  8. Transverse current on strip dipole antenna

    NASA Astrophysics Data System (ADS)

    Wunsch, A. D.

    1982-07-01

    Analyses of the current of thin wire dipole antennas presuppose that the current is parallel to the antenna axis. It is pointed out that a component of current transverse to the antenna axis can exist for antennas having a noncircular cross section, such as the strip dipole. The present investigation is concerned with a perfectly conducting strip antenna which is center driven by a delta function generator, taking into account the surface current-density components Kx(x,z) and Kz(x,z). In the solution of the resulting integral equations, it is assumed that Kz is considerably stronger than the transverse surface current density Kx. After obtaining an approximation to Kz, the second integral equation is solved for Kx. Results for the normalized transverse surface current density are presented in graphs.

  9. PUMPS FOR LIQUID CURRENT-CONDUCTING MATERIAL

    DOEpatents

    Watt, D.A.

    1958-12-23

    An induction-type liquid conductor pump is described wherein the induced current flow is substantially tnansverse to the flow of the liquid in the duct, thus eliminating parallel current flow that tends to cause unwanted pressures resulting in turbulence, eddy-flow, heating losses, and reduced pumping efficiency. This improvement is achieved by offering the parallel current a path of lower impedance along the duct than that offered by the liquid so that the induced currents remaining in the liquid flow in a substantially transverse directlon. Thick copper bars are brazed to the liquid duct parallel to the flow, and additional induced currents are created in the copper bars of appropriate magnitude to balance the ohmic drop ln the current paths outside of the liquid metal.

  10. Absolute geostrophic currents in global tropical oceans

    NASA Astrophysics Data System (ADS)

    Yang, Lina; Yuan, Dongliang

    2016-03-01

    A set of absolute geostrophic current (AGC) data for the period January 2004 to December 2012 are calculated using the P-vector method based on monthly gridded Argo profiles in the world tropical oceans. The AGCs agree well with altimeter geostrophic currents, Ocean Surface Current Analysis-Real time currents, and moored current-meter measurements at 10-m depth, based on which the classical Sverdrup circulation theory is evaluated. Calculations have shown that errors of wind stress calculation, AGC transport, and depth ranges of vertical integration cannot explain non-Sverdrup transport, which is mainly in the subtropical western ocean basins and equatorial currents near the Equator in each ocean basin (except the North Indian Ocean, where the circulation is dominated by monsoons). The identified non-Sverdrup transport is thereby robust and attributed to the joint effect of baroclinicity and relief of the bottom (JEBAR) and mesoscale eddy nonlinearity.

  11. A review of the quantum current standard

    NASA Astrophysics Data System (ADS)

    Kaneko, Nobu-Hisa; Nakamura, Shuji; Okazaki, Yuma

    2016-03-01

    The electric current, voltage, and resistance standards are the most important standards related to electricity and magnetism. Of these three standards, only the ampere, which is the unit of electric current, is an International System of Units (SI) base unit. However, even with modern technology, relatively large uncertainty exists regarding the generation and measurement of current. As a result of various innovative techniques based on nanotechnology and novel materials, new types of junctions for quantum current generation and single-electron current sources have recently been proposed. These newly developed methods are also being used to investigate the consistency of the three quantum electrical effects, i.e. the Josephson, quantum Hall, and single-electron tunneling effects, which are also known as ‘the quantum metrology triangle’. This article describes recent research and related developments regarding current standards and quantum-metrology-triangle experiments.

  12. Towards quantized current arbitrary waveform synthesis

    NASA Astrophysics Data System (ADS)

    Mirovsky, P.; Fricke, L.; Hohls, F.; Kaestner, B.; Leicht, Ch.; Pierz, K.; Melcher, J.; Schumacher, H. W.

    2013-06-01

    The generation of ac modulated quantized current waveforms using a semiconductor non-adiabatic single electron pump is demonstrated. In standard operation, the single electron pump generates a quantized output current of I = ef, where e is the charge of the electron and f is the pumping frequency. Suitable frequency modulation of f allows the generation of ac modulated output currents with different characteristics. By sinusoidal and saw tooth like modulation of f accordingly modulated quantized current waveforms with kHz modulation frequencies and peak currents up to 100 pA are obtained. Such ac quantized current sources could find applications ranging from precision ac metrology to on-chip signal generation.

  13. Conserved currents of double field theory

    NASA Astrophysics Data System (ADS)

    Blair, Chris D. A.

    2016-04-01

    We find the conserved current associated to invariance under generalised diffeomorphisms in double field theory. This can be used to define a generalised Komar integral. We comment on its applications to solutions, in particular to the fundamental string/pp-wave. We also discuss the current in the context of Scherk-Schwarz compactifications. We calculate the current for both the original double field theory action, corresponding to the NSNS sector alone, and for the RR sector.

  14. Pulsed current cathodic protection of well casings

    SciTech Connect

    Bich, N.N.; Bauman, J.

    1995-04-01

    Electric pulses of several hundred volts, applied for very brief periods of time, several thousand times per second, are more effective and economical than conventional steady-state DC currents in protecting deep and/or close-spaced well casings against external corrosion. More uniform current distribution, greater depth of protection, reduced stray current interference, and small anode bed requirements are the main benefits of pulsed technology. Operating principles, equivalent electrical circuits, design considerations, and field cathodic protection logging experience is reviewed.

  15. Eddy currents in a conducting sphere

    NASA Technical Reports Server (NTRS)

    Bergman, John; Hestenes, David

    1986-01-01

    This report analyzes the eddy current induced in a solid conducting sphere by a sinusoidal current in a circular loop. Analytical expressions for the eddy currents are derived as a power series in the vectorial displacement of the center of the sphere from the axis of the loop. These are used for first order calculations of the power dissipated in the sphere and the force and torque exerted on the sphere by the electromagnetic field of the loop.

  16. DC-Compensated Current Transformer †

    PubMed Central

    Ripka, Pavel; Draxler, Karel; Styblíková, Renata

    2016-01-01

    Instrument current transformers (CTs) measure AC currents. The DC component in the measured current can saturate the transformer and cause gross error. We use fluxgate detection and digital feedback compensation of the DC flux to suppress the overall error to 0.15%. This concept can be used not only for high-end CTs with a nanocrystalline core, but it also works for low-cost CTs with FeSi cores. The method described here allows simultaneous measurements of the DC current component. PMID:26805830

  17. Eddy current inspection of graphite fiber components

    NASA Technical Reports Server (NTRS)

    Workman, G. L.; Bryson, C. C.

    1990-01-01

    The recognition of defects in materials properties still presents a number of problems for nondestructive testing in aerospace systems. This project attempts to utilize current capabilities in eddy current instrumentation, artificial intelligence, and robotics in order to provide insight into defining geometrical aspects of flaws in composite materials which are capable of being evaluated using eddy current inspection techniques. The unique capabilities of E-probes and horseshoe probes for inspecting probes for inspecting graphite fiber materials were evaluated and appear to hold great promise once the technology development matures. The initial results are described of modeling eddy current interactions with certain flaws in graphite fiber samples.

  18. Theory of current-drive in plasmas

    SciTech Connect

    Fisch, N.J.

    1986-12-01

    The continuous operation of a tokamak fusion reactor requires, among other things, a means of providing continuous toroidal current. Such operation is preferred to the conventional pulsed operation, where the plasma current is induced by a time-varying magnetic field. A variety of methods has been proposed to provide continuous current, including methods which utilize particle beams or radio frequency waves in any of several frequency regimes. Currents as large as half a mega-amp have now been produced in the laboratory by such means, and experimentation in these techniques has now involved major tokamak facilities worldwide.

  19. Current drag in two leg quantum ladders

    NASA Astrophysics Data System (ADS)

    Giamarchi, Thierry

    2016-03-01

    A two-leg ladder of either interacting bosons or tightly bound cooper pairs is investigated when a supercurrent is forced in one of the legs of the ladder. The two legs of the ladder are connected by a tunneling term. Using a bosonization representation of such an interacting ladder we show that up to a certain critical current the current in the first wire induces an identical supercurrent in the second wire. When this threshold is exceeded vortices are formed in the system and the current in the second wire reduces even if the driving current increases. Potential applications to condensed matter or cold atomic systems are discussed.

  20. Tubular solid oxide fuel cell current collector

    DOEpatents

    Bischoff, Brian L.; Sutton, Theodore G.; Armstrong, Timothy R.

    2010-07-20

    An internal current collector for use inside a tubular solid oxide fuel cell (TSOFC) electrode comprises a tubular coil spring disposed concentrically within a TSOFC electrode and in firm uniform tangential electrical contact with the electrode inner surface. The current collector maximizes the contact area between the current collector and the electrode. The current collector is made of a metal that is electrically conductive and able to survive under the operational conditions of the fuel cell, i.e., the cathode in air, and the anode in fuel such as hydrogen, CO, CO.sub.2, H.sub.2O or H.sub.2S.

  1. Electron currents associated with an auroral band

    NASA Technical Reports Server (NTRS)

    Spiger, R. J.; Anderson, H. R.

    1975-01-01

    Measurements of electron pitch angle distributions and energy spectra over a broad auroral band were used to calculate net electric current carried by auroral electrons in the vicinity of the band. The particle energy spectrometers were carried by a Nike-Tomahawk rocket launched from Poker Flat, Alaska, at 0722 UT on February 25, 1972. Data are presented which indicate the existence of upward field-aligned currents of electrons in the energy range 0.5-20 keV. The spatial relationship of these currents to visual structure of the auroral arc and the characteristics of the electrons carrying the currents are discussed.

  2. Spin-current noise from fluctuation relations

    SciTech Connect

    Lim, Jong Soo; Sánchez, David; López, Rosa

    2013-12-04

    We present fluctuation relations that connect spin-polarized current and noise in mesoscopic conductors. In linear response, these relations are equivalent to the fluctuation-dissipation theorem that relates equilibrium current-current correlations to the linear conductance. More interestingly, in the weakly nonlinear regime of transport, these relations establish a connection between the leading-order rectification spin conductance, the spin noise susceptibility and the third cumulant of spin current fluctuations at equilibrium. Our results are valid even for systems in the presence of magnetic fields and coupled to ferromagnetic electrodes.

  3. Charged particle beam current monitoring tutorial

    SciTech Connect

    Webber, R.C.

    1994-10-01

    A tutorial presentation is made on topics related to the measurement of charged particle beam currents. The fundamental physics of electricity and magnetism pertinent to the problem is reviewed. The physics is presented with a stress on its interpretation from an electrical circuit theory point of view. The operation of devices including video pulse current transformers, direct current transformers, and gigahertz bandwidth wall current style transformers is described. Design examples are given for each of these types of devices. Sensitivity, frequency response, and physical environment are typical parameters which influence the design of these instruments in any particular application. Practical engineering considerations, potential pitfalls, and performance limitations are discussed.

  4. Uniqueness of conserved currents in quantum mechanics

    NASA Astrophysics Data System (ADS)

    Holland, P.

    2003-10-01

    It is proved by a functional method that the conventional expression for the Dirac current is the only conserved 4-vector implied by the Dirac equation that is a function of just the quantum state. The demonstration is extended to derive the unique conserved currents implied by the coupled Maxwell-Dirac equations and the Klein-Gordon equation. The uniqueness of the usual Pauli and Schrödinger currents follows by regarding these as the non-relativistic limits of the Dirac and Klein-Gordon currents, respectively. The existence and properties of further conserved vectors that are not functions of just the state is examined.

  5. Disruption of Helmet Streamers by Current Emergence

    NASA Technical Reports Server (NTRS)

    Guo, W. P.; Wu, S. T.; Tandberg-Hanssen, E.

    1996-01-01

    We have investigated the dynamic response of a coronal helmet streamer to the emergence from below of a current with its magnetic field in a direction opposite to the overlying streamer field. Once the emerging current moves into the closed region of the streamer, a current sheet forms between the emerging field and the streamer field, because the preexisting field and the newly emerging field have opposite polarities. Thus magnetic reconnection will occur at the flanks of the emerged structure where the current density is maximum. If the emerging current is large enough, the energy contained in the current and the reconnection will promptly disrupt the streamer. If the emerging current is small, the streamer will experience a stage of slow evolution. In this stage, slow magnetic reconnection occurring at the flanks of the emerged structure leads to the degeneration of the emerged current to a neutral point. Above this point, a new magnetic bubble will form. The resulting configuration resembles an inverse-polarity prominence. Depending on the initial input energy of the current, the resulting structure will either remain in situ, forming a quasi-static structure, or move upward, forming a coronal transient similar to coronal jets. The numerical method used in this paper can be used to construct helmet streamers containing a detached magnetic structure in their closed field region. The quasi-static solution may serve as a preevent corona for studying coronal mass ejection initiation.

  6. A constant current source for extracellular microiontophoresis.

    PubMed

    Walker, T; Dillman, N; Weiss, M L

    1995-12-01

    A sophisticated constant-current source suitable for extracellular microiontophoresis of tract-tracing substances, such as Phaseolus vulgaris leucoagglutinin, Biocytin or Fluoro-Gold, is described. This design uses a flyback switched-mode power supply to generate controllable high-voltage and operational amplifier circuitry to regulate current and provide instrumentation. Design features include a fast rise time, +/- 2000 V supply (stable output in < 250 ms), simultaneous load current and voltage monitoring, and separate pumping and holding current settings. Three features of this constant-current source make it especially useful for extracellular microiontophoresis. First, the output voltage monitor permits one to follow changes in the microelectrode resistance during current injection. Second, the voltage-limit (or out-of-compliance) indicator circuitry will sound an alarm when the iontophoretic pump is unable to generate the desired current, such as when the micropipette is blocked. Third, the high-compliance voltage power supply insures up to +/- 20 microA of current through 100 M omega resistance. This device has proven itself to be a reliable constant-current source for extracellular microiontophoresis in the laboratory. PMID:8788057

  7. Interhemispheric Field-Aligned Currents: Simulation Results

    NASA Astrophysics Data System (ADS)

    Lyatsky, Sonya

    2016-04-01

    We present simulation results of the 3-D magnetosphere-ionosphere current system including the Region 1, Region 2, and interhemispheric (IHC) field-aligned currents flowing between the Northern and Southern conjugate ionospheres in the case of asymmetry in ionospheric conductivities in two hemispheres (observed, for instance, during the summer-winter seasons). We also computed the maps of ionospheric and equivalent ionospheric currents in two hemispheres. The IHCs are an important part of the global 3-D current system in high-latitude ionospheres. These currents are especially significant during summer and winter months. In the winter ionosphere, they may be comparable and even exceed both Region 1 and Region 2 field-aligned currents. An important feature of these interhemispheric currents is that they link together processes in two hemispheres, so that the currents observed in one hemisphere can provide us with information about the currents in the opposite hemisphere. Despite the significant role of these IHCs in the global 3-D current system, they have not been sufficiently studied yet. The main results of our research may be summarized as follows: 1) In winter hemisphere, the IHCs may significantly exceed and be a substitute for the local Region 1 and Region 2 currents; 2) The IHCs may strongly affect the magnitude, location, and direction of the ionospheric and equivalent ionospheric currents (especially in the nightside winter auroral ionosphere). 3) The IHCs in winter hemisphere may be, in fact, an important (and sometimes even major) source of the Westward Auroral Electrojet, observed in both hemispheres during substorm activity. The study of the contribution from the IHCs into the total global 3-D current system allows us to improve the understanding and forecasting of geomagnetic, auroral, and ionospheric disturbances in two hemispheres. The results of our studies of the Interhemispheric currents are presented in papers: (note: for publications my last

  8. Josephson current in parallel SFS junctions

    NASA Astrophysics Data System (ADS)

    Ioselevich, Pavel; Ostrovsky, Pavel; Fominov, Yakov; Feigelman, Mikhail

    We study a Josephson junction between superconductors connected by two parallel ferromagnetic arms. If the ferromagnets are fully polarised, supercurrent can only flow via Cooper pair splitting between the differently polarised arms. The disorder-average current is suppressed, but mesoscopic fluctuations lead to a significant typical current. We extract the typical current from a current-current correlator. The current is proportional to sin2 α / 2 , where α is the angle between the polarisations of the two arms, revealing the spin dependence of crossed Andreev reflection. Compared to an SNS device of the same geometry, the typical SFS current is small by a factor determined by the properties of the superconducting leads alone. The current is insensitive to the flux threading the area between the ferromagnetic arms of the junction. However, if the ferromagnetic arms are replaced by metal with magnetic impurities, or partially polarised ferromagnets, the Josephson current starts depending on the flux with a period of h / e , i.e. twice the superconducting flux quantum.

  9. How current loops and solenoids curve spacetime

    NASA Astrophysics Data System (ADS)

    Füzfa, André

    2016-01-01

    The curved spacetime around current loops and solenoids carrying arbitrarily large steady electric currents is obtained from the numerical resolution of the coupled Einstein-Maxwell equations in cylindrical symmetry. The artificial gravitational field associated to the generation of a magnetic field produces gravitational redshift of photons and deviation of light. Null geodesics in the curved spacetime of current loops and solenoids are also presented. We finally propose an experimental setup achievable with current technology of superconducting coils, that produces a phase shift of light of the same order of magnitude as astrophysical signals in ground-based gravitational wave observatories.

  10. Hybrid Current Lead Design of HTS SMES

    NASA Astrophysics Data System (ADS)

    Ge, T.; Ren, L.; He, Q.; Jiao, F.; Dong, H.; Jin, T.; Zhou, S.

    In application of Superconducting magnetic energy storage device (SMES), current lead represents a key development component. This paper will focus on parameters and structure design of hybrid high-temperature superconductor (HTS) current lead in a SMES with 100 kJ/100 kW class. Based on the theoretical analysis, finite element simulation (FEA) has been used. It studies the thermal influence of variable cross-sectional area, HTS material and the connection between current lead and cryocooler. Some improvements have been proposed to reduce heat losses. At the end of this paper, a whole procedure about hybrid current lead design is given.

  11. Hybrid high direct current circuit interrupter

    DOEpatents

    Rockot, Joseph H.; Mikesell, Harvey E.; Jha, Kamal N.

    1998-01-01

    A device and a method for interrupting very high direct currents (greater than 100,000 amperes) and simultaneously blocking high voltages (greater than 600 volts). The device utilizes a mechanical switch to carry very high currents continuously with low loss and a silicon controlled rectifier (SCR) to bypass the current around the mechanical switch while its contacts are separating. A commutation circuit, connected in parallel with the SCR, turns off the SCR by utilizing a resonant circuit to divert the SCR current after the switch opens.

  12. Hybrid high direct current circuit interrupter

    DOEpatents

    Rockot, J.H.; Mikesell, H.E.; Jha, K.N.

    1998-08-11

    A device and a method are disclosed for interrupting very high direct currents (greater than 100,000 amperes) and simultaneously blocking high voltages (greater than 600 volts). The device utilizes a mechanical switch to carry very high currents continuously with low loss and a silicon controlled rectifier (SCR) to bypass the current around the mechanical switch while its contacts are separating. A commutation circuit, connected in parallel with the SCR, turns off the SCR by utilizing a resonant circuit to divert the SCR current after the switch opens. 7 figs.

  13. Leakage-current properties of encapsulants

    NASA Technical Reports Server (NTRS)

    Wen, L. C.

    1986-01-01

    A theoretical modeling of leakage current in ethylene vinyl acetate (EVA) and polyvinyl butyral (PVB) modules is being developed and is described. The modeling effort derives mathematical relationships for the bulk and surface conductivites of EVA and PVB, the surface conductivities of glass and polymeric films, and the EVA and PVB pottants, all as functions of environmental parameters. Results from the modeling indicate that for glass/EVA, the glass surface controls the interfacial conductivity, although EVA bulk conductivity controls total leakage current. For PVB/glass, the interface conductivity controls leakage currents for relative humidity (RH) less than 40 to 50%, but PVB bulk conductivity controls leakage current above 50% RH.

  14. Alternating current driven instability in magnetic junctions.

    PubMed

    Epshtein, E M; Zilberman, P E

    2009-04-01

    An effect is considered of alternating (high-frequency) current on the spin-valve-type magnetic junction configuration. The stability with respect to small fluctuations is investigated in the macrospin approximation. When the current frequency is close to the eigenfrequency (precession frequency) of the free layer, parametric resonance occurs. Both collinear configurations, antiparallel and parallel, can become unstable under resonance conditions. The antiparallel configuration can also become unstable under non-resonant conditions. The threshold current density amplitude is of the order of the dc current density for switching of the magnetic junction. PMID:21825350

  15. Equatorial ionospheric currents derived from MAGSAT data

    NASA Technical Reports Server (NTRS)

    Roy, M. (Principal Investigator)

    1983-01-01

    The MAGSAT data on the three component's of the geomagnetic field are subjected to ring current correction and crustal anomaly elimination near the dip equator. The evidence of a strong west east electrojet current below the satellite height (approximately 350 km) is confirmed. Strong evidence of east-west component of the field suggests the existence of a vertical current originating at the jet level and extending upwards. A model calculation shows that such a current system can explain the satellite data as well as the ground data.

  16. Temperature compensated and self-calibrated current sensor using reference current

    DOEpatents

    Yakymyshyn, Christopher Paul; Brubaker, Michael Allen; Yakymyshyn, Pamela Jane

    2008-01-22

    A method is described to provide temperature compensation and self-calibration of a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. A reference electrical current carried by a conductor positioned within the sensing window of the current sensor is used to correct variations in the output signal due to temperature variations and aging.

  17. Enhancing critical current density of cuprate superconductors

    DOEpatents

    Chaudhari, Praveen

    2015-06-16

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

  18. Optical effects of spin currents in semiconductors

    NASA Astrophysics Data System (ADS)

    Wang, Jing

    2011-03-01

    BANG-FEN ZHU, Department of Physics and Institute of Advanced Study, Tsinghua University, REN-BAO LIU, Department of Physics, The Chinese University of Hong Kong -- We predict the linear and second-order nonlinear optical effects of spin currents in semiconductors, based on systematic symmetry analysis and microscopic calculations with realistic models [1, 2]. By an analogue to the Ampere effect and Oersted effect, we conceived and verified that a spin current can be coupled to a ``photon spin curren'' carried by a polarized light beam, which causes sizeable Faraday rotation without involving net magnetization. Furthermore, a spin current can have a strong second-order nonlinear optical effect with unique polarization-dependence due to the special symmetry properties of the spin current. In particular, for a longitudinal spin current, in which the spins point parallel or anti-parallel to the current direction is a chiral quantity, a chiral sum-frequency effect will be induced. The second-order optical effects of spin currents have been experimentally verified immediately after the theoretical prediction. These discoveries represent new phenomena in magneto-optics, with potential spin-photonic applications. They bring new opportunities to research of spintronics and may also facilitate research of topological insulators where the edge states form pure spin currents. This work was supported by the NSFC Grant Nos.10574076, 10774086, and the Basic Research Program of China Grant 2006CB921500, Hong Kong RGC HKU 10/CRF/08 and Hong Kong GRF CUHK 402207.

  19. Runaway electrons in plasma current sheets

    SciTech Connect

    Gurevich, A.V.; Sudan, R.N. )

    1994-01-31

    It is shown that a runaway electron population accelerates along the main magnetic field in a Sweet-Parker current sheet. After a characteristic distance the entire current is carried by runaways. The thickness of this runaway sheet is much smaller than the original Ohmic sheet. The influence of microinstabilities is discussed.

  20. 49 CFR 229.77 - Current collectors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Current collectors. 229.77 Section 229.77 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....77 Current collectors. (a) Pantographs shall be so arranged that they can be operated from...