WorldWideScience

Sample records for extremely high magnetic

  1. Generation of bright circularly-polarized extreme ultraviolet high harmonics for magnetic circular dichroism spectroscopy

    CERN Document Server

    Kfir, Ofer; Turgut, Emrah; Knut, Ronny; Zusin, Dmitriy; Popmintchev, Dimitar; Popmintchev, Tenio; Nembach, Hans; Shaw, Justin M; Fleicher, Avner; Kapteyn, Henry; Murnane, Margaret; Cohen, Oren

    2014-01-01

    Circularly-polarized extreme UV and X-ray radiation provides valuable access to the structural, electronic and magnetic properties of materials. To date, such experiments have been possible only using large-scale free-electron lasers or synchrotrons. Here we demonstrate the first bright extreme UV circularly-polarized high harmonics and use this new light source for magnetic circular dichroism measurements at the M-shell absorption edges of cobalt. This work paves the way towards element-specific imaging and spectroscopy of multiple elements simultaneously in magnetic and other chiral media with very high spatio-temporal resolution, all on a tabletop.

  2. Magnetic slippery extreme icephobic surfaces

    Science.gov (United States)

    Irajizad, Peyman; Hasnain, Munib; Farokhnia, Nazanin; Sajadi, Seyed Mohammad; Ghasemi, Hadi

    2016-11-01

    Anti-icing surfaces have a critical footprint on daily lives of humans ranging from transportation systems and infrastructure to energy systems, but creation of these surfaces for low temperatures remains elusive. Non-wetting surfaces and liquid-infused surfaces have inspired routes for the development of icephobic surfaces. However, high freezing temperature, high ice adhesion strength, and high cost have restricted their practical applications. Here we report new magnetic slippery surfaces outperforming state-of-the-art icephobic surfaces with a ice formation temperature of -34 °C, 2-3 orders of magnitude higher delay time in ice formation, extremely low ice adhesion strength (~2 Pa) and stability in shear flows up to Reynolds number of 105. In these surfaces, we exploit the magnetic volumetric force to exclude the role of solid-liquid interface in ice formation. We show that these inexpensive surfaces are universal and can be applied to all types of solids (no required micro/nano structuring) with no compromise to their unprecedented properties.

  3. Gravity and Extreme Magnetism SMEX

    Science.gov (United States)

    2012-01-01

    The Gravity and Extreme Magnetism SMEX mission will be the first mission to catalogue the X-ray polarisation of many astrophysical objects including black-holes and pulsars. This first of its kind mission is enabled by the novel use of a time projection chamber as an X-ray polarimeter. The detector has been developed over the last 5 years, with the current effort charged toward a demonstration of it's technical readiness to be at level 6 prior to the preliminary design review. This talk will describe the design GEMS polarimeter and the results to date from the engineering test unit.

  4. Magnetic Reconnection in Extreme Astrophysical Environments

    CERN Document Server

    Uzdensky, Dmitri A

    2011-01-01

    Magnetic reconnection is a basic plasma process of dramatic rearrangement of magnetic topology, often leading to a violent release of magnetic energy. It is important in magnetic fusion and in space and solar physics --- areas that have so far provided the context for most of reconnection research. Importantly, these environments consist just of electrons and ions and the dissipated energy always stays with the plasma. In contrast, in this paper I introduce a new direction of research, motivated by several important problems in high-energy astrophysics --- reconnection in high energy density (HED) radiative plasmas, where radiation pressure and radiative cooling become dominant factors in the pressure and energy balance. I identify the key processes distinguishing HED reconnection: special-relativistic effects; radiative effects (radiative cooling, radiation pressure, and Compton resistivity); and, at the most extreme end, QED effects, including pair creation. I then discuss the main astrophysical application...

  5. A multireader reliability study comparing conventional high-field magnetic resonance imaging with extremity low-field MRI in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Bird, Paul; Ejbjerg, Bo; Lassere, Marissa;

    2007-01-01

    The use of extremity low-field magnetic resonance imaging (E-MRI) is increasing, but relatively few data exist on its reproducibility and accuracy in comparison with high-field MRI, especially for multiple readers. The aim of this multireader exercise of rheumatoid arthritis wrist...

  6. A multireader reliability study comparing conventional high-field magnetic resonance imaging with extremity low-field MRI in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Bird, Paul; Ejbjerg, Bo; Lassere, Marissa;

    2007-01-01

    The use of extremity low-field magnetic resonance imaging (E-MRI) is increasing, but relatively few data exist on its reproducibility and accuracy in comparison with high-field MRI, especially for multiple readers. The aim of this multireader exercise of rheumatoid arthritis wrist and metacarpoph...

  7. The design of the inelastic neutron scattering mode for the Extreme Environment Diffractometer with the 26 T High Field Magnet

    Energy Technology Data Exchange (ETDEWEB)

    Bartkowiak, Maciej, E-mail: maciej.bartkowiak@helmholtz-berlin.de; Stüßer, Norbert; Prokhnenko, Oleksandr

    2015-10-11

    The Extreme Environment Diffractometer is a neutron time-of-flight instrument, designed to work with a constant-field hybrid magnet capable of reaching fields over 26 T, unprecedented in neutron science; however, the presence of the magnet imposes both spatial and technical limitations on the surrounding instrument components. In addition to the existing diffraction and small-angle neutron scattering modes, the instrument will operate also in an inelastic scattering mode, as a direct time-of-flight spectrometer. In this paper we present the Monte Carlo ray-tracing simulations, the results of which illustrate the performance of the instrument in the inelastic-scattering mode. We describe the focussing neutron guide and the chopper system of the existing instrument and the planned design for the instrument upgrade. The neutron flux, neutron spatial distribution, divergence distribution and energy resolution are calculated for standard instrument configurations.

  8. Magnetic Logic Circuits for Extreme Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The program aims to demonstrate a new genre of all-magnetic logic circuits which are radiation-tolerant and capable of reliable operation in extreme environmental...

  9. On Destroying Extremal Magnetized Black Holes

    CERN Document Server

    Siahaan, Haryanto M

    2016-01-01

    The gedanken experiment by Wald to destroy a black hole using a test particle in the equatorial plane is adopted to the case of extremal magnetized black holes. We find that the presence of external magnetic fields resulting from the "magnetization" process using a Harrison-like transformation permits the test particle to have energies in the range which allows the destruction of black holes. However, from the corresponding effective potential we find that the test particle which may destroy the black hole can never reach the horizon.

  10. Magnetic Fields inside Extremely Fast Shock Waves

    NARCIS (Netherlands)

    Wiersma, J.

    2007-01-01

    The aim of my research on magnetic fields in extremely fast shock waves has been to predict the properties of shock waves that move almost with the speed of light. These shocks are created in the tenuous interstellar medium by catastrophic events such as the explosion of stars many times heavier

  11. Magnetic Fields inside Extremely Fast Shock Waves

    NARCIS (Netherlands)

    Wiersma, J.

    2007-01-01

    The aim of my research on magnetic fields in extremely fast shock waves has been to predict the properties of shock waves that move almost with the speed of light. These shocks are created in the tenuous interstellar medium by catastrophic events such as the explosion of stars many times heavier

  12. Possible Kondo-Lattice-Enhanced Magnetic Ordering at Anomalously High Temperature in Nd Metal under Extreme Compression

    Science.gov (United States)

    Schilling, James S.; Song, Jing; Soni, Vikas; Lim, Jinhyuk

    Most elemental lanthanides order magnetically at temperatures To well below ambient, the highest being 292 K for Gd. Sufficiently high pressure is expected to destabilize the well localized magnetic 4 f state of the heavy lanthanides, leading to increasing influence of Kondo physics on the RKKY interaction. For pressures above 80 GPa, To for Dy and Tb begins to increase dramatically, extrapolating for Dy to a record-high value near 400 K at 160 GPa. This anomalous increase may be an heretofore unrecognized feature of the Kondo lattice state; if so, one would expect To to pass through a maximum and fall rapidly at even higher pressures. A parallel is suggested to the ferromagnet CeRh3B2 where To = 115 K at ambient pressure, a temperature more than 100-times higher than anticipated from simple de Gennes scaling. Here we discuss recent experiments on Nd where anomalous behavior in To (P) is found to occur at lower pressures, perhaps reflecting the fact that Nd's 4 f wave function is less localized. Work at Washington University is supported by NSF Grant DMR-1104742 and CDAC through NNSA/DOE Grant DE-FC52-08NA28554.

  13. Magnetic-Driven Winds from Post-AGB Stars: Solutions for High Speed Winds and Extreme Collimation

    CERN Document Server

    García-Segura, G; Franco, J; Garcia-Segura, Guillermo; Lopez, Jose Alberto; Franco, Jose

    2004-01-01

    This paper explores the effects of post-AGB winds driven solely by magnetic pressure from the stellar surface. It is found that winds can reach high speeds under this assumption, and lead to the formation of highly collimated proto-planetary nebulae. Bipolar knotty jets with periodic features and constant velocity are well reproduced by the models. Several wind models with terminal velocities from a few tens of $\\kms$ up to $10^3$ $\\kms$ are calculated, yielding outflows with linear momenta in the range $10^{36}-10^{40} \\gcms$, and kinetic energies in the range $10^{42}-10^{47} $ erg. These results are in accord with recent observations of proto-planetary nebulae that have pointed out serious energy and momentum deficits if radiation pressure is considered as the only driver for these outflows. Our models strengthen the notion that the large mass-loss rates of post-AGB stars, together with the short transition times from the late AGB to the planetary nebula stage, could be directly linked with the generation ...

  14. Occurrence rate of extreme magnetic storms

    CERN Document Server

    Yermolaev, Yu I; Nikolaeva, N S; Yermolaev, M Yu

    2013-01-01

    Statistical analysis of occurrence rate of magnetic storms induced by different types of interplanetary drivers is made on the basis of OMNI data for period 1976-2000. Using our catalog of large scale types of solar wind streams we study storms induced by interplanetary coronal mass ejections (ICME) (separately magnetic clouds (MC) and Ejecta) and both types of compressed regions: corotating interaction regions (CIR) and Sheaths. For these types of drivers we calculate integral probabilities of storms with minimum Dst < -50, -70, -100, -150, and -200 nT. The highest probability in this interval of Dst is observed for MC, probabilities for other drivers are 3-10 times lower than for MC. Extrapolation of obtained results to extreme storms shows that such a magnetic storm as Carrington storm in 1859 with Dst = -1760 nT is observed on the Earth with frequency 1 event during ~500 year.

  15. Relativistic QED Plasma at Extremely High Temperature

    CERN Document Server

    Masood, Samina S

    2016-01-01

    Renormalization scheme of QED (Quantum Electrodynamics) at high temperatures is used to calculate the effective parameters of relativistic plasma in the early universe. Renormalization constants of QED play role of effective parameters of the theory and can be used to determine the collective behavior of the medium. We explicitly show that the dielectric constant, magnetic reluctivity, Debye length and the plasma frequency depend on temperature in the early universe. Propagation speed, refractive index, plasma frequency and Debye shielding length of a QED plasma are computed at extremely high temperatures in the early universe. We also found the favorable conditions for the relativistic plasma from this calculations.

  16. Extreme Transients in the High Energy Universe

    Science.gov (United States)

    Kouveliotou, Chryssa

    2013-01-01

    The High Energy Universe is rich in diverse populations of objects spanning the entire cosmological (time)scale, from our own present-day Milky Way to the re-ionization epoch. Several of these are associated with extreme conditions irreproducible in laboratories on Earth. Their study thus sheds light on the behavior of matter under extreme conditions, such as super-strong magnetic fields (in excess of 10^14 G), high gravitational potentials (e.g., Super Massive Black Holes), very energetic collimated explosions resulting in relativistic jet flows (e.g., Gamma Ray Bursts, exceeding 10^53 ergs). In the last thirty years, my work has been mostly focused on two apparently different but potentially linked populations of such transients: magnetars (highly magnetized neutron stars) and Gamma Ray Bursts (strongly beamed emission from relativistic jets), two populations that constitute unique astrophysical laboratories, while also giving us the tools to probe matter conditions in the Universe to redshifts beyond z=10, when the first stars and galaxies were assembled. I did not make this journey alone I have either led or participated in several international collaborations studying these phenomena in multi-wavelength observations; solitary perfection is not sufficient anymore in the world of High Energy Astrophysics. I will describe this journey, present crucial observational breakthroughs, discuss key results and muse on the future of this field.

  17. Dynamos at extreme magnetic Prandtl numbers

    CERN Document Server

    Verma, Mahendra K

    2015-01-01

    We present a MHD shell model suitable for the computation of various energy fluxes of magnetohydrodynamic turbulence for very small and very large magnetic Prandtl numbers $\\mathrm{Pm}$; such computations are inaccessible to direct numerical simulations. For small $\\mathrm{Pm}$, we observe that the both kinetic and magnetic energy spectra scale as $k^{-5/3}$ in the inertial range, but the dissipative magnetic energy scales as $k^{-17/3}$. Here, the kinetic energy at large length scale feeds the large-scale magnetic field that cascades to small-scale magnetic field, which gets dissipated by Joule heating. The large $\\mathrm{Pm}$ dynamo has a similar behaviour except that the dissipative kinetic energy scales as $k^{-13/3}$. For this case, the large-scale velocity field transfers energy to large-scale magnetic field, which gets transferred to small-scale velocity and magnetic fields. The energy of the small-scale magnetic field also gets transferred to the small-scale velocity field. The energy accumulated at s...

  18. Analysis of the Extremely Low Frequency Magnetic Field Emission from Laptop Computers

    Directory of Open Access Journals (Sweden)

    Brodić Darko

    2016-03-01

    Full Text Available This study addresses the problem of magnetic field emission produced by the laptop computers. Although, the magnetic field is spread over the entire frequency spectrum, the most dangerous part of it to the laptop users is the frequency range from 50 to 500 Hz, commonly called the extremely low frequency magnetic field. In this frequency region the magnetic field is characterized by high peak values. To examine the influence of laptop’s magnetic field emission in the office, a specific experiment is proposed. It includes the measurement of the magnetic field at six laptop’s positions, which are in close contact to its user. The results obtained from ten different laptop computers show the extremely high emission at some positions, which are dependent on the power dissipation or bad ergonomics. Eventually, the experiment extracts these dangerous positions of magnetic field emission and suggests possible solutions.

  19. The Gravity and Extreme Magnetism Small Explorer (GEMS)

    Science.gov (United States)

    Kallman, T. R.

    2011-01-01

    The Gravity and Extreme Magnetism Small Explorer (GEMS) was selected by NASA for flight in 2014 to make a sensitive search for X-ray polarization from a wide set of source classes, including stellar black holes, Seyfert galaxies and quasars, blazars, rotation and accretion-powered pulsars, magnetars, shell supernova remnants and pulsar wind nebulae. Among the primary scientific objectives are determining the effects of the spin of black holes and the geometry of supermassive black hole accretion, determining the configurations of the magnetic fields and the X-ray emission of magnetars, and determining the magnetic structure of the supernova shocks in which cosmic rays are accelerated. GEMS will observe 23 targets during a 16 month prime mission, in observations that will be able to reach predicted levels of polarization. The mission can be extended to provide a guest observer phase. The GEMS instrument has time projection chamber polarimeters with high 2-10 keV efficiency at the focus of thin foil mirrors. The 4.5 m focal length mirrors will be deployed on an extended boom. The spacecraft with the instrument is rotated with a period of about 10 minutes to enable measurement and correction of systematic errors. A small Bragg reflection soft X-ray experiment takes advantage of this rotation to obtain a measurement at 0.5 keV. The design of the GEMS instrument and the mission, the expected performance and the planned science program will be discussed.

  20. The impact of high-frequency magnetic stimulation of peripheral nerves: muscle hardness, venous blood flow, and motor function of upper extremity in healthy subjects.

    Science.gov (United States)

    Okudera, Yoshihiko; Matsunaga, Toshiki; Sato, Mineyoshi; Chida, Satoaki; Hatakeyama, Kazutoshi; Watanabe, Motoyuki; Shimada, Yoichi

    2015-01-01

    The purpose of this study was to investigate the impact of high-frequency peripheral nerve magnetic stimulation on the upper limb function. Twenty-five healthy adults (16 men and 9 women) participated in this study. The radial nerve of the non-dominant hand was stimulated by high-frequency magnetic stimulation device. A total of 600 impulses were applied at a frequency of 20 Hz and intensity of 1.2 resting motor threshold (rMT). At three time points (before, immediately after, and 15 min after stimulation), muscle hardness of the extensor digitorum muscle on the stimulated side was measured using a mechanical tissue hardness meter and a shear wave imaging device, cephalic venous blood flow on the stimulated side was measured using an ultrasound system, and the Box and Block test (BBT) was performed. Mechanical tissue hardness results did not show any significant differences between before, immediately after, and 15 min after stimulation. Measurements via shear wave imaging showed that muscle hardness significantly decreased both immediately and 15 min after stimulation compared to before stimulation (P nerve magnetic stimulation can achieve effects similar to electrical stimulation in a less invasive manner, and may therefore become an important element in next-generation rehabilitation.

  1. Extremely High Q-factor metamaterials due to Anapole Excitation

    CERN Document Server

    Basharin, Alexey A; Volsky, Nikita; Kafesaki, Maria; Economou, Eleftherios N

    2016-01-01

    We demonstrate that ideal anapole metamaterials have infinite Q-factor. We have designed and fabricated a metamaterial consisting of planar metamolecules which exhibit anapole behavior in the sense that the electric dipole radiation is almost cancelled by the toroidal dipole one, producing thus an extremely high Q-factor at the resonance frequency. The size of the system, at the mm range, and the parasitic magnetic quadrupole radiation are the factors limiting the size of the Q-factor. In spite of the very low radiation losses the local fields at the metamolecules are extremely high, of the order of higher than the external incoming field.

  2. Abnormalities of the upper extremities on fetal magnetic resonance imaging.

    Science.gov (United States)

    Nemec, S F; Kasprian, G; Brugger, P C; Bettelheim, D; Amann, G; Nemec, U; Rotmensch, S; Graham, J M; Rimoin, D L; Lachman, R S; Prayer, D

    2011-11-01

    In view of the increasing use of fetal magnetic resonance imaging (MRI) as an adjunct to prenatal ultrasonography, we sought to demonstrate the visualization of upper extremity abnormalities and associated defects on MRI, with regard to fetal outcomes and compared with ultrasound imaging. This retrospective study included 29 fetuses with upper extremity abnormalities visualized with fetal MRI following suspicious ultrasound findings and confirmed by postnatal assessment or autopsy. On a 1.5-Tesla unit, dedicated sequences were applied to image the extremities. Central nervous system (CNS) and extra-CNS anomalies were assessed to define extremity abnormalities as isolated or as complex, with associated defects. Fetal outcome was identified from medical records. MRI and ultrasound findings, when available, were compared. Isolated upper extremity abnormalities were found in three (10.3%) fetuses. In 26 (89.7%) fetuses complex abnormalities, including postural extremity disorders (21/26) and structural extremity abnormalities (15/26), were demonstrated. Associated defects involved: face (15/26); musculoskeletal system (14/26); thorax and cardio/pulmonary system (12/26); lower extremities (12/26); brain and skull (10/26); and abdomen (8/26). Of the 29 cases, 18 (62.1%) pregnancies were delivered and 11 (37.9%) were terminated. MRI and US findings were compared in 27/29 cases: the diagnosis was concordant in 14 (51.9%) of these cases, and additional findings were made on MRI in 13/27 (48.1%) cases. Visualization of upper extremity abnormalities on fetal MRI enables differentiation between isolated defects and complex ones, which may be related to poor fetal prognosis. MRI generally confirms the ultrasound diagnosis, and may provide additional findings in certain cases. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.

  3. Extremely low frequency magnetic fields and health risks

    Directory of Open Access Journals (Sweden)

    M.I. Buzdugan

    2009-10-01

    Full Text Available In a world abounding in artificially created electromagnetic fields, we consider that a new approach regarding their possible harmful effects on living beings becomes mandatory. The paper reviews briefly the results of some epidemiological studies, the ICNIRP (International Committee on Non-Ionizing Radiation Protection Guidelines and the latest document of the SCENIHR (an organism of the European Commission regarding extremely low frequency (ELF magnetic fields. We are convinced that the best conduct that might be adopted on this matter is the policy of the prudential avoidance. Several examples of possible harmful effects determined by extremely low frequency magnetic fields dedicated to building services engineering in residences are presented, along with several methods of mitigating them.

  4. Fault Tolerant Magnetic Bearing Testing and Conical Magnetic Bearing Development for Extreme Temperature Environments

    Science.gov (United States)

    Keith, Theo G., Jr.; Clark, Daniel

    2004-01-01

    During the six month tenure of the grant, activities included continued research of hydrostatic bearings as a viable backup-bearing solution for a magnetically levitated shaft system in extreme temperature environments (1000 F), developmental upgrades of the fault-tolerant magnetic bearing rig at the NASA Glenn Research Center, and assisting in the development of a conical magnetic bearing for extreme temperature environments, particularly turbomachinery. It leveraged work from the ongoing Smart Efficient Components (SEC) and the Turbine-Based Combined Cycle (TBCC) program at NASA Glenn Research Center. The effort was useful in providing technology for more efficient and powerful gas turbine engines.

  5. EXTREMELY LOW FREQUENCY MAGNETIC FIELD SUSCEPTIBILITY OF VISUAL DISPLAY UNITS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Extremely low frequency (ELF) magnetic field susceptibility is an index of visual display unit (VDU) quality and performance. This paper provided field measured data on the susceptibility for a large variety of VDUs. A test rig was built to study the susceptibility of VDUs to magnetic fields at fundamental and third harmonic frequencies. It was found that the susceptibility level is largely dependent on refresh rate of the VDU and the orientation of the external ELF field. It was also found that the VDU susceptibility is significantly increased in the presence of harmonic frequency magnetic fields. About 30% of the tested samples have susceptibility levels higher than that stated in IEC 1000-4-8 standard.

  6. Extremely high magnetic-field sensitivity of charge transport in the Mn/SiO2/p-Si hybrid structure

    Science.gov (United States)

    Volkov, N. V.; Tarasov, A. S.; Smolyakov, D. A.; Gustaitsev, A. O.; Rautskii, M. V.; Lukyanenko, A. V.; Volochaev, M. N.; Varnakov, S. N.; Yakovlev, I. A.; Ovchinnikov, S. G.

    2017-01-01

    We report on abrupt changes in dc resistance and impedance of a diode with the Schottky barrier based on the Mn/SiO2/p-Si structure in a magnetic field. It was observed that at low temperatures the dc and ac resistances of the device change by a factor of more than 106 with an increase in a magnetic field to 200 mT. The strong effect of the magnetic field is observed only above the threshold forward bias across the diode. The ratios between ac and dc magnetoresistances can be tuned from almost zero to 108% by varying the bias. To explain the diversity of magnetotransport phenomena observed in the Mn/SiO2/p-Si structure, it is necessary to attract several mechanisms, which possibly work in different regions of the structure. The anomalously strong magnetotransport effects are attributed to the magnetic-field-dependent impact ionization in the bulk of a Si substrate. At the same time, the conditions for this process are specified by structure composition, which, in turn, affects the current through each structure region. The effect of magnetic field attributed to suppression of impact ionization via two mechanisms leads to an increase in the carrier energy required for initiation of impact ionization. The first mechanism is related to displacement of acceptor levels toward higher energies relative to the top of the valence band and the other mechanism is associated with the Lorentz forces affecting carrier trajectories between scatterings events. The estimated contributions of these two mechanisms are similar. The proposed structure is a good candidate for application in CMOS technology-compatible magnetic- and electric-field sensors and switching devices.

  7. Extremely high magnetic-field sensitivity of charge transport in the Mn/SiO2/p-Si hybrid structure

    Directory of Open Access Journals (Sweden)

    N. V. Volkov

    2017-01-01

    Full Text Available We report on abrupt changes in dc resistance and impedance of a diode with the Schottky barrier based on the Mn/SiO2/p-Si structure in a magnetic field. It was observed that at low temperatures the dc and ac resistances of the device change by a factor of more than 106 with an increase in a magnetic field to 200 mT. The strong effect of the magnetic field is observed only above the threshold forward bias across the diode. The ratios between ac and dc magnetoresistances can be tuned from almost zero to 108% by varying the bias. To explain the diversity of magnetotransport phenomena observed in the Mn/SiO2/p-Si structure, it is necessary to attract several mechanisms, which possibly work in different regions of the structure. The anomalously strong magnetotransport effects are attributed to the magnetic-field-dependent impact ionization in the bulk of a Si substrate. At the same time, the conditions for this process are specified by structure composition, which, in turn, affects the current through each structure region. The effect of magnetic field attributed to suppression of impact ionization via two mechanisms leads to an increase in the carrier energy required for initiation of impact ionization. The first mechanism is related to displacement of acceptor levels toward higher energies relative to the top of the valence band and the other mechanism is associated with the Lorentz forces affecting carrier trajectories between scatterings events. The estimated contributions of these two mechanisms are similar. The proposed structure is a good candidate for application in CMOS technology-compatible magnetic- and electric-field sensors and switching devices.

  8. Extremely high Q-factor toroidal metamaterials

    CERN Document Server

    Basharin, Alexey A; Volsky, Nikita; Kafesaki, Maria; Economou, Eleftherios N; Ustinov, Alexey V

    2016-01-01

    We demonstrate that, owing to the unique topology of the toroidal dipolar mode, its electric/magnetic field can be spatially confined within subwavelength, externally accessible regions of the metamolecules, which makes the toroidal planar metamaterials a viable platform for high Q-factor resonators due to interfering toroidal and other dipolar modes in metamolecules.

  9. Extremely high Q -factor metamaterials due to anapole excitation

    Science.gov (United States)

    Basharin, Alexey A.; Chuguevsky, Vitaly; Volsky, Nikita; Kafesaki, Maria; Economou, Eleftherios N.

    2017-01-01

    We have designed and fabricated a metamaterial consisting of planar metamolecules which exhibit unusual, almost perfect anapole behavior in the sense that the electric dipole radiation is almost canceled by the toroidal dipole one, producing thus an extremely high Q -factor at the resonance frequency. Thus we have demonstrated theoretically and experimentally that metamaterials approaching ideal anapole behavior have very high Q -factor. The size of the system, at the millimeter range, and the parasitic magnetic quadrupole radiation are the factors limiting the size of the Q -factor. In spite of the very low radiation losses the estimated local fields at the metamolecules are extremely high, of the order of 104 higher than the external incoming field.

  10. Synchrotron Applications of High Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    This workshop aims at discussing the scientific potential of X-ray diffraction and spectroscopy in magnetic fields above 30 T. Pulsed magnetic fields in the range of 30 to 40 T have recently become available at Spring-8 and the ESRF (European synchrotron radiation facility). This document gathers the transparencies of the 6 following presentations: 1) pulsed magnetic fields at ESRF: first results; 2) X-ray spectroscopy and diffraction experiments by using mini-coils: applications to valence state transition and frustrated magnet; 3) R{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}: an ideal system to be studied in X-ray under high magnetic field?; 4) high field studies at the Advanced Photon Source: present status and future plans; 5) synchrotron X-ray diffraction studies under extreme conditions; and 6) projects for pulsed and steady high magnetic fields at the ESRF.

  11. High Performance Magnets

    Science.gov (United States)

    2000-03-29

    Our efforts in this project were focused on three different materials, namely; interstitial Sm-Fe carbides and nitrides, high energy product Nd2Fe14B ...magnets with MgO addition, and nanocomposite Nd2Fe14B /alpha-Fe consisting of a fine mixture of hard and soft phases. In the Sm-Fe carbides and

  12. Extremely high frequency RF effects on electronics.

    Energy Technology Data Exchange (ETDEWEB)

    Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

    2012-01-01

    The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

  13. Extremely compliant and highly stretchable patterned graphene

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Shuze; Huang, Yinjun; Li, Teng, E-mail: LiT@umd.edu [Department of Mechanical Engineering and Maryland NanoCenter, University of Maryland, College Park, Maryland 20742 (United States)

    2014-04-28

    Graphene is intrinsically ultra-stiff in its plane. Its huge mechanical mismatch when interfacing with ultra-compliant biological tissues and elastomers (7–9 orders of magnitude difference in stiffness) poses significant challenge in its application to functional devices such as epidermal electronics and sensing prosthesis. We offer a feasible and promising solution to this significant challenge by suitably patterning graphene into a nanomesh. Through systematic coarse-grained simulations, we show that graphene nanomesh can be made extremely compliant with nearly zero stiffness up to about 20% elongation and then remain highly compliant up to about 50% elongation.

  14. Extreme ultra-violet movie camera for imaging microsecond time scale magnetic reconnection.

    Science.gov (United States)

    Chai, Kil-Byoung; Bellan, Paul M

    2013-12-01

    An ultra-fast extreme ultra-violet (EUV) movie camera has been developed for imaging magnetic reconnection in the Caltech spheromak/astrophysical jet experiment. The camera consists of a broadband Mo:Si multilayer mirror, a fast decaying YAG:Ce scintillator, a visible light block, and a high-speed visible light CCD camera. The camera can capture EUV images as fast as 3.3 × 10(6) frames per second with 0.5 cm spatial resolution. The spectral range is from 20 eV to 60 eV. EUV images reveal strong, transient, highly localized bursts of EUV radiation when magnetic reconnection occurs.

  15. Extreme Precipitation and High-Impact Landslides

    Science.gov (United States)

    Kirschbaum, Dalia; Adler, Robert; Huffman, George; Peters-Lidard, Christa

    2012-01-01

    It is well known that extreme or prolonged rainfall is the dominant trigger of landslides; however, there remain large uncertainties in characterizing the distribution of these hazards and meteorological triggers at the global scale. Researchers have evaluated the spatiotemporal distribution of extreme rainfall and landslides at local and regional scale primarily using in situ data, yet few studies have mapped rainfall-triggered landslide distribution globally due to the dearth of landslide data and consistent precipitation information. This research uses a newly developed Global Landslide Catalog (GLC) and a 13-year satellite-based precipitation record from Tropical Rainfall Measuring Mission (TRMM) data. For the first time, these two unique products provide the foundation to quantitatively evaluate the co-occurence of precipitation and rainfall-triggered landslides globally. The GLC, available from 2007 to the present, contains information on reported rainfall-triggered landslide events around the world using online media reports, disaster databases, etc. When evaluating this database, we observed that 2010 had a large number of high-impact landslide events relative to previous years. This study considers how variations in extreme and prolonged satellite-based rainfall are related to the distribution of landslides over the same time scales for three active landslide areas: Central America, the Himalayan Arc, and central-eastern China. Several test statistics confirm that TRMM rainfall generally scales with the observed increase in landslide reports and fatal events for 2010 and previous years over each region. These findings suggest that the co-occurrence of satellite precipitation and landslide reports may serve as a valuable indicator for characterizing the spatiotemporal distribution of landslide-prone areas in order to establish a global rainfall-triggered landslide climatology. This research also considers the sources for this extreme rainfall, citing

  16. Instrumentation development for magnetic and structural studies under extremes of pressure and temperature

    OpenAIRE

    Giriat, Gaetan

    2012-01-01

    The study of the magnetic and structural properties of matter under extreme conditions is a fast developing field. With the emergence of new techniques and innovative instruments for measuring physical properties, the need for compatible pressure generating devices is constantly growing. The work described in this thesis is focused on development, construction and testing of several high pressure (HP) cells of novel design. One of the cells is intended for single crystal X-r...

  17. Instrumentation development for magnetic and structural studies under extremes of pressure and temperature

    OpenAIRE

    Giriat, Gaetan

    2012-01-01

    The study of the magnetic and structural properties of matter under extreme conditions is a fast developing field. With the emergence of new techniques and innovative instruments for measuring physical properties, the need for compatible pressure generating devices is constantly growing. The work described in this thesis is focused on development, construction and testing of several high pressure (HP) cells of novel design. One of the cells is intended for single crystal X-r...

  18. Extremely low-frequency electromagnetic fields disrupt magnetic alignment of ruminants.

    Science.gov (United States)

    Burda, Hynek; Begall, Sabine; Cervený, Jaroslav; Neef, Julia; Nemec, Pavel

    2009-04-07

    Resting and grazing cattle and deer tend to align their body axes in the geomagnetic North-South direction. The mechanism(s) that underlie this behavior remain unknown. Here, we show that extremely low-frequency magnetic fields (ELFMFs) generated by high-voltage power lines disrupt alignment of the bodies of these animals with the geomagnetic field. Body orientation of cattle and roe deer was random on pastures under or near power lines. Moreover, cattle exposed to various magnetic fields directly beneath or in the vicinity of power lines trending in various magnetic directions exhibited distinct patterns of alignment. The disturbing effect of the ELFMFs on body alignment diminished with the distance from conductors. These findings constitute evidence for magnetic sensation in large mammals as well as evidence of an overt behavioral reaction to weak ELFMFs in vertebrates. The demonstrated reaction to weak ELFMFs implies effects at the cellular and molecular levels.

  19. TRICKS Magnetic Resonance Angiography at 3-Tesla for Assessing Whole Lower Extremity Vascular Tree in Patients with High-Grade Critical Limb Ischemia: DSA and TASC II Guidelines Correlations

    Directory of Open Access Journals (Sweden)

    Sheung-Fat Ko

    2012-01-01

    Full Text Available The entire vascular tree of 58 lower extremities with high-grade critical limb ischemia (CLI was assessed with three-station time resolved imaging of contrast kinetics (TRICKS magnetic resonance angiography (T-MRA and correlated with digital subtraction angiography (DSA examinations and Trans-Atlantic Inter-Society Consensus II (TASC II guidelines. Kappa (κ statistics were utilized to evaluate the agreement of stenosis scores (5-point scale; 0 normal to 4 occlusion based on T-MRA and DSA. With DSA as the standard, significant stenosis instances (stenosis score ≥2 among vascular segments were compared. The κ-statistics of image quality (4-point scale; 1 nondiagnostic to 4 excellent of T-MRA and TASC II classification assessed by a radiologist and a vascular surgeon were also evaluated. Among 870 vascular segments, excellent agreement was observed between T-MRA and DSA (mean κ = 0.883 in revealing stenosis (mean stenosis score, 2.1  ±  1.3 versus 2.0  ±  1.3. T-MRA harbored overall high sensitivity (99.5%, specificity (93.6%, positive predictive value (95.4%, negative predictive value (99.6%, and accuracy (97.7% in depicting significant stenosis. Excellent interobserver agreement (mean κ = 0.818 of superb image quality (mean score = 3.5–3.6 of T-MRA and outstanding agreement of TASC II classification of aortoiliac and femoral-popliteal lesions (κ = 0.912–0.917 between two raters further verified the clinical feasibility of T-MRA for treatment planning.

  20. Extreme Environment High Temperature Communication Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this project is to develop and demonstrate a communications system capable of operation at extreme temperatures and pressures in hostile and corrosive...

  1. Assessment of extremely low frequency magnetic field exposure from GSM mobile phones.

    Science.gov (United States)

    Calderón, Carolina; Addison, Darren; Mee, Terry; Findlay, Richard; Maslanyj, Myron; Conil, Emmanuelle; Kromhout, Hans; Lee, Ae-kyoung; Sim, Malcolm R; Taki, Masao; Varsier, Nadège; Wiart, Joe; Cardis, Elisabeth

    2014-04-01

    Although radio frequency (RF) electromagnetic fields emitted by mobile phones have received much attention, relatively little is known about the extremely low frequency (ELF) magnetic fields emitted by phones. This paper summarises ELF magnetic flux density measurements on global system for mobile communications (GSM) mobile phones, conducted as part of the MOBI-KIDS epidemiological study. The main challenge is to identify a small number of generic phone models that can be used to classify the ELF exposure for the different phones reported in the study. Two-dimensional magnetic flux density measurements were performed on 47 GSM mobile phones at a distance of 25 mm. Maximum resultant magnetic flux density values at 217 Hz had a geometric mean of 221 (+198/-104) nT. Taking into account harmonic data, measurements suggest that mobile phones could make a substantial contribution to ELF exposure in the general population. The maximum values and easily available variables were poorly correlated. However, three groups could be defined on the basis of field pattern indicating that manufacturers and shapes of mobile phones may be the important parameters linked to the spatial characteristics of the magnetic field, and the categorization of ELF magnetic field exposure for GSM phones in the MOBI-KIDS study may be achievable on the basis of a small number of representative phones. Such categorization would result in a twofold exposure gradient between high and low exposure based on type of phone used, although there was overlap in the grouping.

  2. Conical Magnetic Bearing Development and Magnetic Bearing Testing for Extreme Temperature Environments

    Science.gov (United States)

    Keith, Theo G., Jr.; Jansen, Mark

    2004-01-01

    The main proposed research of this grant were: to design a high-temperature, conical magnetic bearing facility, to test the high-temperature, radial magnetic bearing facility to higher speeds, to investigate different backup bearing designs and materials, to retrofit the high-temperature test facility with a magnetic thrust bearing, to evaluate test bearings at various conditions, and test several lubricants using a spiral orbit tribometer. A high-temperature, conical magnetic bearing facility has been fully developed using Solidworks. The facility can reuse many of the parts of the current high-temperature, radial magnetic bearing, helping to reduce overall build costs. The facility has the ability to measure bearing force capacity in the X, Y, and Z directions through a novel bearing mounting design. The high temperature coils and laminations, a main component of the facility, are based upon the current radial design and can be fabricated at Texas A&M University. The coil design was highly successful in the radial magnetic bearing. Vendors were contacted about fabrication of the high temperature lamination stack. Stress analysis was done on the laminations. Some of the components were procured, but due to budget cuts, the facility build up was stopped.

  3. High performance soft magnetic materials

    CERN Document Server

    2017-01-01

    This book provides comprehensive coverage of the current state-of-the-art in soft magnetic materials and related applications, with particular focus on amorphous and nanocrystalline magnetic wires and ribbons and sensor applications. Expert chapters cover preparation, processing, tuning of magnetic properties, modeling, and applications. Cost-effective soft magnetic materials are required in a range of industrial sectors, such as magnetic sensors and actuators, microelectronics, cell phones, security, automobiles, medicine, health monitoring, aerospace, informatics, and electrical engineering. This book presents both fundamentals and applications to enable academic and industry researchers to pursue further developments of these key materials. This highly interdisciplinary volume represents essential reading for researchers in materials science, magnetism, electrodynamics, and modeling who are interested in working with soft magnets. Covers magnetic microwires, sensor applications, amorphous and nanocrystalli...

  4. Magnetic storms and solar flares: can be analysed within similar mathematical framework with other extreme events?

    Science.gov (United States)

    Balasis, Georgios; Potirakis, Stelios M.; Papadimitriou, Constantinos; Zitis, Pavlos I.; Eftaxias, Konstantinos

    2015-04-01

    The field of study of complex systems considers that the dynamics of complex systems are founded on universal principles that may be used to describe a great variety of scientific and technological approaches of different types of natural, artificial, and social systems. We apply concepts of the nonextensive statistical physics, on time-series data of observable manifestations of the underlying complex processes ending up to different extreme events, in order to support the suggestion that a dynamical analogy characterizes the generation of a single magnetic storm, solar flare, earthquake (in terms of pre-seismic electromagnetic signals) , epileptic seizure, and economic crisis. The analysis reveals that all the above mentioned different extreme events can be analyzed within similar mathematical framework. More precisely, we show that the populations of magnitudes of fluctuations included in all the above mentioned pulse-like-type time series follow the traditional Gutenberg-Richter law as well as a nonextensive model for earthquake dynamics, with similar nonextensive q-parameter values. Moreover, based on a multidisciplinary statistical analysis we show that the extreme events are characterized by crucial common symptoms, namely: (i) high organization, high compressibility, low complexity, high information content; (ii) strong persistency; and (iii) existence of clear preferred direction of emerged activities. These symptoms clearly discriminate the appearance of the extreme events under study from the corresponding background noise.

  5. High field superconducting magnets

    Science.gov (United States)

    Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

    2011-01-01

    A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

  6. Probing the local, electronic and magnetic structure of matter under extreme conditions of temperature and pressure

    DEFF Research Database (Denmark)

    Torchio, R.; Boccato, S.; Cerantola, V.;

    2016-01-01

    In this paper we present recent achievements in the field of investigation of the local, electronic and magnetic structure of the matter under extreme conditions of pressure and temperature. These results were obtained thanks to the coupling of a compact laser heating system to the energy......-dispersive XAS technique available on the ID24 beamline at the ESRF synchrotron. The examples chosen concern the melting and the liquid structure of 3d metals and alloys under high pressures (HPs) and the observation of temperature-induced spin crossover in FeCO3 at HP....

  7. The Gravity and Extreme Magnetism Small Expolorer Mission

    Science.gov (United States)

    Kallman, Timothy R.; Swank, J.; Jahoda, K.; GEMS Team

    2011-01-01

    Polarization is an inherently geometric quantity and provides information on source geometry inaccessible via spectroscopy or timing. To date, there have been reliable detections of X-ray polarization from only one object outside the solar system (the Crab nebula). Recent development of photoelectric polarimetry makes it possible to perform sensitive X-ray polarimetry with a modest mission. GEMS was recently selected by NASA to be the 13th Small Explorer mission with launch planned for 2014. GEMS will be 100× more sensitive than any previously flown X-ray polarimeter and should provide useful polarization measurements for dozens of sources, to lower than predicted levels. GEMS will lead to new insights into the nature of accreting black holes, highly magnetized neutron stars, and supernova remnants.

  8. Critical endpoint in the QCD phase diagram for extremely strong background magnetic fields

    CERN Document Server

    Endrodi, Gergely

    2015-01-01

    Lattice simulations have demonstrated that a background (electro)magnetic field reduces the chiral/deconfinement transition temperature of quantum chromodynamics for eB < 1 GeV^2. On the level of observables, this reduction manifests itself in an enhancement of the Polyakov loop and in a suppression of the light quark condensates (inverse magnetic catalysis) in the transition region. In this paper, we report on lattice simulations of 1+1+1-flavor QCD at an unprecedentedly high value of the magnetic field eB = 3.25 GeV^2. Based on the behavior of various observables, it is shown that even at this extremely strong field, inverse magnetic catalysis prevails and the transition, albeit becoming sharper, remains an analytic crossover. In addition, we develop an algorithm to directly simulate the asymptotically strong magnetic field limit of QCD. We find strong evidence for a first-order deconfinement phase transition in this limiting theory, implying the presence of a critical endpoint in the QCD phase diagram. ...

  9. [Mechanism of action of combined extremely weak magnetic field on aqueous solution of amino acid].

    Science.gov (United States)

    Zhadin, M N; Bakharev, B V; Bobkova, N V

    2014-01-01

    The fundamental physical mechanisms of resonance action of an extremely weak (40 nT) alternating magnetic field at the cyclotron frequency combined with a weak (40 μT) static magnetic field, on living systems are analyzed in the present work. The experimental effects of such sort of magnetic fields were described in different papers: the very narrow resonant peaks in electrical conductivity of the aqueous solutions in the in vitro experiments and the biomedical in vivo effects on living animals of magnetic fields with frequencies tuned to some amino acids. The existing experimental in vitro data had a good repeatability in different laboratories and countries. Unfortunately, for free ions such sort of effects are absolutely impossible because the dimensions of an ion rotation radius should be measured by meters at room temperature and at very low static magnetic fields used in all the above experiments. Even for bound ions these effects should be also absolutely impossible from the positions of classic physics because of rather high viscosity of biological liquid media (blood plasma, cerebrospinal liquid, cytoplasm). Only modern quantum electrodynamics of condensed media opens the new ways for solving these problems. The proposed article is devoted to analysis of quantum mechanisms of these effects.

  10. Dynamos at extreme magnetic Prandtl numbers: insights from shell models

    Science.gov (United States)

    Verma, Mahendra K.; Kumar, Rohit

    2016-12-01

    We present an MHD shell model suitable for computation of various energy fluxes of magnetohydrodynamic turbulence for very small and very large magnetic Prandtl numbers $\\mathrm{Pm}$; such computations are inaccessible to direct numerical simulations. For small $\\mathrm{Pm}$, we observe that both kinetic and magnetic energy spectra scale as $k^{-5/3}$ in the inertial range, but the dissipative magnetic energy scales as $k^{-11/3}\\exp(-k/k_\\eta)$. Here, the kinetic energy at large length scale feeds the large-scale magnetic field that cascades to small-scale magnetic field, which gets dissipated by Joule heating. The large-$\\mathrm{Pm}$ dynamo has a similar behaviour except that the dissipative kinetic energy scales as $k^{-13/3}$. For this case, the large-scale velocity field transfers energy to the large-scale magnetic field, which gets transferred to small-scale velocity and magnetic fields; the energy of the small-scale magnetic field also gets transferred to the small-scale velocity field, and the energy thus accumulated is dissipated by the viscous force.

  11. Extremal Black Holes in Strong Magnetic Fields: Near-Horizon Geometries and Meissner Effect

    CERN Document Server

    Hejda, Filip

    2016-01-01

    For extremal black holes, one can construct simpler, limiting spacetimes that describe the geometry near degenerate horizons. Since these spacetimes are known to have enhanced symmetry, the limiting objects coincide for different solutions. We show that this occurs for strongly magnetised Kerr-Newman solution, and how this is related to physical Meissner effect of expulsion of magnetic fields from extremal black holes.

  12. High temperature superconductor accelerator magnets

    NARCIS (Netherlands)

    van Nugteren, J.

    2016-01-01

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding 20T. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and dev

  13. Multiscale structures of resistive magnetic reconnection at high magnetic Reynolds numbers

    Science.gov (United States)

    Miyoshi, Takahiro; Kusano, Kanya

    Magnetic reconnection is the most important process of explosive phenomena in space plasmas. The magnetic Reynolds number for the space plasmas are extremely high in general since those plasmas are thought to be collisionless or semi-collisional. However, magnetic reconnection rate becomes low as magnetic Reynolds number increases within the framework of a stationary resistive MHD model. Thus, modern models of magnetic reconnection often include kinetic effects such as the Hall effect to explain realistic explosive magnetic reconnection. It is thought, on the other hand, that the MHD approximation is valid for the plasmas within a very wide range of scales since the scale gap between the macro-and micro-scale is quite large, e.g., in the solar corona, the ratio of the macro to micro will be more than 107 . Such multiscale structures of MHD with wide range of scales, however, have not been clarified so far. Therefore, in this paper, resistive magnetic reconnection at high magnetic Reynolds numbers are investigated using very high-resolution MHD simulations. Simulation results show that the magnetic energy at high magnetic Reynolds numbers is explosively released, while that at not-so-high magnetic Reynolds numbers is steadily dissipated. In the case of high magnetic Reynolds numbers, multiple small scale plasmoids are intermittently created and ejected via secondary tearing modes in a nonlinearly developed thin current sheet. It is revealed that a secondary plasmoid is not only accelerated up to a local magnetosonic speed toward the down-stream region but also perturbs the up-stream region. Thus, complicated multiscale structures appear around the magnetic field reversal layer. Perspective for the high-resolution simulation of extremely high magnetic Reynolds numbers will be also discussed.

  14. Assessment of extremely low frequency magnetic field exposure from GSM mobile phones

    NARCIS (Netherlands)

    Calderón, Carolina; Addison, Darren; Mee, Terry; Findlay, Richard; Maslanyj, Myron; Conil, Emmanuelle; Kromhout, Hans; Lee, Ae Kyoung; Sim, Malcolm R.; Taki, Masao; Varsier, Nadège; Wiart, Joe; Cardis, Elisabeth

    2014-01-01

    Although radio frequency (RF) electromagnetic fields emitted by mobile phones have received much attention, relatively little is known about the extremely low frequency (ELF) magnetic fields emitted by phones. This paper summarises ELF magnetic flux density measurements on global system for mobile c

  15. Common lower extremity injuries in female high school soccer ...

    African Journals Online (AJOL)

    Common lower extremity injuries in female high school soccer players in ... and fitness and not wearing shin guards are risk factors for injury in female soccer ... do not differ from the studies done in male adolescent and adult soccer players.

  16. Advanced Extremely High Frequency Satellite (AEHF)

    Science.gov (United States)

    2015-12-01

    High Frequency Satellite (AEHF) is a joint service satellite communications system that provides global , survivable, secure, protected, and jam...three satellites fully integrated into the Milstar constellation. October 2014: On October 16, 2014, the program received PEO certification for the...Combined Orbital Operation, Logistics Sustainment ( COOLS ) contract, it will be completed and coordinated in CY 2016. The AEHF system being sustained

  17. Workshop on extremely high energy density plasmas and their diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Shozo (ed.)

    2001-09-01

    Compiled are the papers presented at the workshop on 'Extremely High Energy Density Plasmas and Their Diagnostics' held at National Institute for Fusion Science. The papers cover physics and applications of extremely high-energy density plasmas such as dense z-pinch, plasma focus, and intense pulsed charged beams. Separate abstracts were presented for 7 of the papers in this report. The remaining 25 were considered outside the subject scope of INIS. (author)

  18. High-frequency magnetic components

    CERN Document Server

    Kazimierczuk, Marian K

    2009-01-01

    If you are looking for a complete study of the fundamental concepts in magnetic theory, read this book. No other textbook covers magnetic components of inductors and transformers for high-frequency applications in detail. This unique text examines design techniques of the major types of inductors and transformers used for a wide variety of high-frequency applications including switching-mode power supplies (SMPS) and resonant circuits. It describes skin effect and proximity effect in detail to provide you with a sound understanding of high-frequency phenomena. As well as this, you will disco

  19. Extremely low frequency electric and magnetic fields as risk factors in chemical industry.

    Science.gov (United States)

    Troptcheva, T; Ivanova, M; Israel, M

    1998-09-01

    The risk assessment for staff in the chemical industry is usually related to accident hazards, production emergencies, blast and fire danger, or to the adverse effects of toxic substances. The combined effect of electric and magnetic fields with other factors combined with other hazards and working conditions, has not yet been studied. In all branches of industry, the members of staff who endure the most exposure to electric and magnetic fields, are electricians. This group is considered at high risk because of the increased probability of cancer. We studied electric and magnetic fields with low frequencies in the nitrogen chemical fertilizer plant "HIMCO", Vratza. Sources of extremely low frequency fields (50 Hz) are local thermal power plants, substations, open (110 kV) and closed (6 kV and 0.4 kV) distribution devices, transformers, compressors and turbocompressors, command halls, and video display units. The methods used for assessing exposure of low frequency electric and magnetic fields were based on the separate measurement of the electric and magnetic components of the field, using spot measurements and evaluation of the real time duration of exposure for different staff groups. The measured values for the different staff groups were within the limits of national and international standards. The measured magnetic flux densities in the "HIMCO" plant exceeded 3 mG, a value which is considered by many investigations in the literature, as a possible carcinogenic factor. The prolonged exposure to low frequency electric and magnetic fields determines the place of these physical factors in the complex of hazardous environmental factors for the staff. The simultaneous performance of combined investigations of all risk factors would result in the complete risk assessment for staff in the chemical industry. Electricians are considered to be a professional group who have an increased risk of contracting cancer. Extensive measurement and assessment of exposure of the

  20. Exposure of children to extremely low frequency magnetic fields in France: Results of the EXPERS study.

    Science.gov (United States)

    Magne, Isabelle; Souques, Martine; Bureau, Isabelle; Duburcq, Anne; Remy, Emmanuel; Lambrozo, Jacques

    2017-09-01

    The assessment of magnetic field exposure in children is an important point in the context of epidemiological issues. EXPERS is the first study ever carried out measuring personal exposure to extremely low frequency magnetic fields at a national scale, involving 977 French children with 24 h personal measurements. Descriptive statistical analyses were performed for all the children, and only for children where no alarm clock was identified, as in some cases this requirement of the measurement protocol was not respected. The proportion of children with a 24 h arithmetic mean of ≥0.4 μT was 3.1% when considering all children and 0.8% when excluding alarm clocks. The alarm clocks were the main variable linked to the child exposure measurements. Magnetic field exposure increased when the home was located close to a high voltage power line. However, none of the 0.8% of children living at 0.4 μT. A multiple correspondence analysis showed the difficulty to build a statistical model predicting child exposure. The distribution of child personal exposure was significantly different from the distribution of exposure during sleep, questioning the exposure assessment in some epidemiological studies.

  1. High resolution spectroscopy of six new extreme helium stars

    Science.gov (United States)

    Heber, U.; Jones, G.; Drilling, J. S.

    1986-01-01

    High resolution spectra of six newly discovered extreme helium stars are presented. LSS 5121 is shown to be a spectroscopical twin of the hot extreme helium star HD 160641. A preliminary LTE analysis of LSS 3184 yielded an effective temperature of 22,000 K and a surface gravity of log g = 3.2. Four stars form a new subgroup, classified by sharp-lined He I spectra and pronounced O II spectra, and it is conjectured that these lie close to the Eddington limit. The whole group of extreme helium stars apparently is inhomogeneous with respect to luminosity to mass ratio and chemical composition.

  2. Extreme Particle Acceleration via Magnetic Reconnection in the Crab Nebula

    Science.gov (United States)

    Cerutti, Benoit; Uzdensky, D. A.; Begelman, M. C.

    2012-01-01

    The discovery by Agile and Fermi of intense day-long synchrotron gamma-ray flares above 100 MeV in the Crab Nebula challenges classical models of pulsar wind nebulae and particle acceleration. We argue that the flares are powered by magnetic reconnection in the nebula. Using relativistic test-particle simulations, we show that particles are naturally focused into a thin fan beam, deep inside the reconnection layer where the magnetic field is small. The particles then suffer less from synchrotron losses and pile up at the maximum energy given by the electric potential drop in the layer. Applying this model to the Crab Nebula, we find that the emerging synchrotron emission spectrum above 100 MeV is consistent with the September 2010 flare observations. No detectable emission is expected at other wavelengths. This scenario provides a viable explanation for the Crab Nebula gamma-ray flares.

  3. Magnetic Properties of Erbium Gallium Gallate under High Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    Zhang Xijuan; Cheng Haiying; Yang Cuihong; Wang Wei

    2004-01-01

    A theoretical investigation on the magnetic properties of rare-earth Er3+ in Er3 Ga5 O12 was reported. The average magnetic moments(M) for applied magnetic field H parallel to the [001 ], [ 100], [ 110], [ 111 ] direction was studied based on the quantum theory. Temperature dependence of the magnetic properties is analyzed for H applied parallel to the [ 100] and [ 111 ] crystallographic directions. The magnetization decreases with increasing temperature,showing good agreement with thermal effect. A strong anisotropy of the magnetization is found under high magnetic field, but when the magnetic field is small, M and H are proportional.

  4. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

    AUTHOR|(CDS)2079328; de Rijk, Gijs; Dhalle, Marc

    2016-11-10

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding $20T$. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and development before they can be applied in a practical accelerator magnet. In order to study HTS in detail, a five tesla demonstrator magnet named Feather-M2 is designed and constructed. The magnet is based on ReBCO coated conductor, which is assembled into a $10kA$ class Roebel cable. A new and optimized Aligned Block layout is used, which takes advantage of the anisotropy of the conductor. This is achieved by providing local alignment of the Roebel cable in the coil windings with the magnetic field lines. A new Network Model capable of analyzing transient electro-magnetic and thermal phenomena in coated conductor cables and coils is developed. This model is necessary to solve critical issues in coated conductor ac...

  5. Extreme states of matter high energy density physics

    CERN Document Server

    Fortov, Vladimir E

    2016-01-01

    With its many beautiful colour pictures, this book gives fascinating insights into the unusual forms and behaviour of matter under extremely high pressures and temperatures. These extreme states are generated, among other things, by strong shock, detonation and electric explosion waves, dense laser beams,electron and ion beams, hypersonic entry of spacecraft into dense atmospheres of planets, and in many other situations characterized by extremely high pressures and temperatures.Written by one of the world's foremost experts on the topic, this book will inform and fascinate all scientists dealing with materials properties and physics, and also serve as an excellent introduction to plasma-, shock-wave and high-energy-density physics for students and newcomers seeking an overview. This second edition is thoroughly revised and expanded, in particular with new material on high energy-density physics, nuclear explosions and other nuclear transformation processes.

  6. High-Sensitivity Magnetization Measurements

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The three most common instruments for high-sensitivity magnetization measurements (the vibrating-sample magnetometer, the alternating gradient magnetometer, and the SQUID magne tometer) are described and their limiting sensitivities are discussed. The advantages and disad vantages of each are described. Magnetometers using micro-machined force detectors are briefly mentioned.

  7. Extremely weak magnetic field exposure may inhibit hippocampal neurogenesis of Sprague Dawley rats

    Science.gov (United States)

    Zhang, B.; Tian, L.; Cai, Y.; Xu, H.; Pan, Y.

    2016-12-01

    Hippocampal neurogenesis occurs throughout life in mammals brains and can be influenced by animals' age as well as environmental factors. Lines of evidences have shown that the magnetic field is an important physics environmental factor influencing many animals' growth and development, and extremely weak magnetic field exposures have been proved having serious adverse effects on the metabolism and behaviors in some animals, but few studies have examined the response of hippocampal neurogenesis to it. In the present study, we experimentally examined the extremely weak magnetic field effects on neurogenesis of the dentate gyrus (DG) of hippocampus of adult Sprague Dawley (SD) rats. Two types of magnetic fields were used, an extremely weak magnetic field (≤ 0.5μT) and the geomagnetic fields (strength 31-58μT) as controls. Thirty-two SD rats (3-weeks old) were used in this study. New cell survival in hippocampus was assessed at 0, 14, 28, and 42 days after a 7-day intraperitoneal injections of 5-bromo-2'-deoxyuridine (BrdU). Meanwhile, the amounts of immature neurons and mature neurons which are both related to hippocampal neurogenesis, as documented by labeling with doublecortin (DCX) and neuron (NeuN), respectively, were also analyzed at 0, 14, 28, and 42 days. Compared with geomagnetic field exposure groups, numbers of BrdU-, DCX-positive cells of DG of hippocampus in tested rats reduces monotonously and more rapidly after 14 days, and NeuN-positive cells significantly decreases after 28days when exposed in the extremely weak magnetic field condition. Our data suggest that the exposure to an extremely weak magnetic field may suppress the neurogenesis in DG of SD rats.

  8. Extreme ultraviolet imaging of three-dimensional magnetic reconnection in a solar eruption.

    Science.gov (United States)

    Sun, J Q; Cheng, X; Ding, M D; Guo, Y; Priest, E R; Parnell, C E; Edwards, S J; Zhang, J; Chen, P F; Fang, C

    2015-06-26

    Magnetic reconnection, a change of magnetic field connectivity, is a fundamental physical process in which magnetic energy is released explosively, and it is responsible for various eruptive phenomena in the universe. However, this process is difficult to observe directly. Here, the magnetic topology associated with a solar reconnection event is studied in three dimensions using the combined perspectives of two spacecraft. The sequence of extreme ultraviolet images clearly shows that two groups of oppositely directed and non-coplanar magnetic loops gradually approach each other, forming a separator or quasi-separator and then reconnecting. The plasma near the reconnection site is subsequently heated from ∼1 to ≥5 MK. Shortly afterwards, warm flare loops (∼3 MK) appear underneath the hot plasma. Other observational signatures of reconnection, including plasma inflows and downflows, are unambiguously revealed and quantitatively measured. These observations provide direct evidence of magnetic reconnection in a three-dimensional configuration and reveal its origin.

  9. Extremely long-lived magnetic excitations in supported Fe chains

    Science.gov (United States)

    Gauyacq, J. P.; Lorente, N.

    2016-07-01

    We report on a theoretical study of the lifetime of the first excited state of spin chains made of an odd number of Fe atoms on C u2N /Cu (100 ) . Yan, Choi, Burgess, Rolf-Pissarczyk, and Loth [Nat. Nanotech. 10, 40 (2015), 10.1038/nnano.2014.281] recently observed very long lifetimes in the case of F e3 chains. We consider the decay of the first excited state induced by electron-hole pair creation in the substrate. For a finite magnetic field, the two lowest-lying states in the chain have a quasi-Néel state structure. Decay from one state to the other strongly depends on the degree of entanglement of the local spins in the chain. The weak entanglement in the chain accounts for the long lifetimes that increase exponentially with chain length. Despite their apparently very different properties, the behavior of odd and even chains is governed by the same kind of phenomena, in particular entanglement effects. The present results account quite well for the lifetimes recently measured by Yan et al. on F e3 .

  10. Prospects of extreme ultraviolet radiation sources based on microwave discharge for high-resolution lithography

    Science.gov (United States)

    Abramov, I. S.; Gospodchikov, E. D.; Shalashov, A. G.

    2017-07-01

    In this paper, inspired by the success of recent experiments, we discuss a new possible type of sources of extreme ultraviolet radiation for the semiconductor industry, based on the radiating plasma with multiply charged ions supported in a mirror magnetic trap by high-power microwaves. We propose a simple theory that describes the main features of such source, perform modeling for a wide range of plasma parameters and magnetic configurations, compare the results to the existing experimental data, and study the prospects of the new scheme in present technological circumstances.

  11. Extremely low-frequency magnetic field exposure, electrical shocks and risk of Parkinson's disease

    NARCIS (Netherlands)

    van der Mark, Marianne; Vermeulen, Roel; Nijssen, Peter C. G.; Mulleners, Wim M.; Sas, Antonetta M. G.; van Laar, Teus; Kromhout, Hans; Huss, Anke

    2015-01-01

    Previous studies did not provide strong evidence for an increased Parkinson's disease (PD) risk after exposure to extremely low-frequency magnetic fields (ELF-MF), but were limited in their scope to address other exposures related to the use of electricity such as electrical shocks. We evaluated the

  12. Extremely low-frequency magnetic field exposure, electrical shocks and risk of Parkinson's disease

    NARCIS (Netherlands)

    van der Mark, Marianne; Vermeulen, Roel; Nijssen, Peter C. G.; Mulleners, Wim M.; Sas, Antonetta M. G.; van Laar, Teus; Kromhout, Hans; Huss, Anke

    Previous studies did not provide strong evidence for an increased Parkinson's disease (PD) risk after exposure to extremely low-frequency magnetic fields (ELF-MF), but were limited in their scope to address other exposures related to the use of electricity such as electrical shocks. We evaluated the

  13. Extremely low-frequency magnetic field exposure, electrical shocks and risk of Parkinson's disease

    NARCIS (Netherlands)

    van der Mark, Marianne; Vermeulen, Roel; Nijssen, Peter C G; Mulleners, Wim M; Sas, Antonetta M G; van Laar, Teus; Kromhout, Hans; Huss, Anke

    2015-01-01

    PURPOSE: Previous studies did not provide strong evidence for an increased Parkinson's disease (PD) risk after exposure to extremely low-frequency magnetic fields (ELF-MF), but were limited in their scope to address other exposures related to the use of electricity such as electrical shocks. We eval

  14. Extremely low-frequency magnetic fields and survival from childhood acute lymphoblastic leukemia

    DEFF Research Database (Denmark)

    Schüz, J; Grell, K; Kinsey, S

    2012-01-01

    A previous US study reported poorer survival in children with acute lymphoblastic leukemia (ALL) exposed to extremely low-frequency magnetic fields (ELF-MF) above 0.3 μT, but based on small numbers. Data from 3073 cases of childhood ALL were pooled from prospective studies conducted in Canada...

  15. Range Detection of the Extremely Low-Frequency Magnetic Field Produced by Laptop's AC Adapter

    Science.gov (United States)

    Brodić, Darko; Amelio, Alessia

    2017-02-01

    Human exposure to extremely low frequency magnetic field represents a risk to their health. This paper takes into consideration the level of an extremely low-frequency magnetic field between 30 and 300 Hz emitted by an AC laptop adapter. The experiment consists of testing 17 different AC adapters for laptops. During the testing, laptops are operated in a normal operating conditions as well as under heavy load. The magnetic field measurement is conducted in the area around the AC adapter. Obtained data is evaluated according to the critical level of the magnetic field proposed by safety standards. Furthermore, data is classified by a K-medians method in order to determine the critical levels of the magnetic field exposure in the nearby area of the AC adapter. Obtained classifications are evaluated according to safety standards, giving a critical analysis of magnetic field areas at risk. Due to emission of a very strong magnetic field in certain areas, a recommendation for safety use of the AC adapter is proposed.

  16. Is Extremely High Life Satisfaction during Adolescence Advantageous?

    Science.gov (United States)

    Suldo, Shannon M.; Huebner, E. Scott

    2006-01-01

    This study examined whether extremely high life satisfaction was associated with adaptive functioning or maladaptive functioning. Six hundred ninety-eight secondary level students completed the Students' Life Satisfaction Scale [Huebner, 1991a, School Psychology International, 12, pp. 231-240], Youth Self-Report of the Child Behavior Checklist…

  17. common lower extremity injuries in female high school soccer ...

    African Journals Online (AJOL)

    studies on soccer concentrate on male soccer players.5-7 Although participation ... the prevalence and injury profile of lower extremity injuries in female high school ... An extended duration of skills (p=0.0001) and fitness (p=0.02) training in this .... The results (Table V) show that shin guards were associated with a reduced ...

  18. Extreme high-head portables provide more pumping options

    Energy Technology Data Exchange (ETDEWEB)

    Fiscor, S.

    2006-10-15

    Three years ago, Godwin Pumps, one of the largest manufacturers of portable pumps, introduced its Extreme Duty High Lift (HL) series of pumps and more mines are finding unique applications for these pumps. The Extreme HL series is a range single-stage Dri-Prime pumps with heads up to 600 feet and flows up to 5,000 gallons per minute. The American Coal Co.'s Galatia mine, an underground longwall mine in southern Illinois, used an HL 160 to replace a multiple-staged centrifugal pump. It provided Galatia with 1,500 gpm at 465 ft. 3 photos.

  19. Extreme Ultraviolet Imaging of Three-dimensional Magnetic Reconnection in a Solar Eruption

    CERN Document Server

    Sun, J Q; Ding, M D; Guo, Y; Priest, E R; Parnell, C E; Edwards, S J; Zhang, J; Chen, P F; Fang, C

    2015-01-01

    Magnetic reconnection, a change of magnetic field connectivity, is a fundamental physical process in which magnetic energy is released explosively. It is responsible for various eruptive phenomena in the universe. However, this process is difficult to observe directly. Here, the magnetic topology associated with a solar reconnection event is studied in three dimensions (3D) using the combined perspectives of two spacecraft. The sequence of extreme ultraviolet (EUV) images clearly shows that two groups of oppositely directed and non-coplanar magnetic loops gradually approach each other, forming a separator or quasi-separator and then reconnecting. The plasma near the reconnection site is subsequently heated from $\\sim$1 to $\\ge$5 MK. Shortly afterwards, warm flare loops ($\\sim$3 MK) appear underneath the hot plasma. Other observational signatures of reconnection, including plasma inflows and downflows, are unambiguously revealed and quantitatively measured. These observations provide direct evidence of magneti...

  20. High resolution modelling of extreme precipitation events in urban areas

    Science.gov (United States)

    Siemerink, Martijn; Volp, Nicolette; Schuurmans, Wytze; Deckers, Dave

    2015-04-01

    The present day society needs to adjust to the effects of climate change. More extreme weather conditions are expected, which can lead to longer periods of drought, but also to more extreme precipitation events. Urban water systems are not designed for such extreme events. Most sewer systems are not able to drain the excessive storm water, causing urban flooding. This leads to high economic damage. In order to take appropriate measures against extreme urban storms, detailed knowledge about the behaviour of the urban water system above and below the streets is required. To investigate the behaviour of urban water systems during extreme precipitation events new assessment tools are necessary. These tools should provide a detailed and integral description of the flow in the full domain of overland runoff, sewer flow, surface water flow and groundwater flow. We developed a new assessment tool, called 3Di, which provides detailed insight in the urban water system. This tool is based on a new numerical methodology that can accurately deal with the interaction between overland runoff, sewer flow and surface water flow. A one-dimensional model for the sewer system and open channel flow is fully coupled to a two-dimensional depth-averaged model that simulates the overland flow. The tool uses a subgrid-based approach in order to take high resolution information of the sewer system and of the terrain into account [1, 2]. The combination of using the high resolution information and the subgrid based approach results in an accurate and efficient modelling tool. It is now possible to simulate entire urban water systems using extreme high resolution (0.5m x 0.5m) terrain data in combination with a detailed sewer and surface water network representation. The new tool has been tested in several Dutch cities, such as Rotterdam, Amsterdam and The Hague. We will present the results of an extreme precipitation event in the city of Schiedam (The Netherlands). This city deals with

  1. Extreme ultraviolet emission and confinement of tin plasmas in the presence of a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Amitava, E-mail: roy@fzu.cz, E-mail: aroy@barc.gov.in [School of Nuclear Engineering and Center for Materials Under Extreme Environment(CMUXE), Purdue University, West Lafayette, Indiana 47907 (United States); HiLASE Project, Department of Diode-pumped Lasers, Institute of Physics of the ASCR, Na Slovance 2, 18221 Prague (Czech Republic); Murtaza Hassan, Syed; Harilal, Sivanandan S.; Hassanein, Ahmed [School of Nuclear Engineering and Center for Materials Under Extreme Environment(CMUXE), Purdue University, West Lafayette, Indiana 47907 (United States); Endo, Akira; Mocek, Tomas [HiLASE Project, Department of Diode-pumped Lasers, Institute of Physics of the ASCR, Na Slovance 2, 18221 Prague (Czech Republic)

    2014-05-15

    We investigated the role of a guiding magnetic field on extreme ultraviolet (EUV) and ion emission from a laser produced Sn plasma for various laser pulse duration and intensity. For producing plasmas, planar slabs of pure Sn were irradiated with 1064 nm, Nd:YAG laser pulses with varying pulse duration (5–15 ns) and intensity. A magnetic trap was fabricated with the use of two neodymium permanent magnets which provided a magnetic field strength ∼0.5 T along the plume expansion direction. Our results indicate that the EUV conversion efficiency do not depend significantly on applied axial magnetic field. Faraday Cup ion analysis of Sn plasma show that the ion flux reduces by a factor of ∼5 with the application of an axial magnetic field. It was found that the plasma plume expand in the lateral direction with peak velocity measured to be ∼1.2 cm/μs and reduced to ∼0.75 cm/μs with the application of an axial magnetic field. The plume expansion features recorded using fast photography in the presence and absence of 0.5 T axial magnetic field are simulated using particle-in-cell code. Our simulation results qualitatively predict the plasma behavior.

  2. M-H loop tracer based on digital signal processing for low frequency characterization of extremely thin magnetic wires

    Energy Technology Data Exchange (ETDEWEB)

    Butta, M.; Ripka, P. [Department of Measurement, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague 16627 (Czech Republic); Infante, G.; Badini-Confalonieri, G. A.; Vazquez, M. [Instituto de Ciencia de Materiales de Madrid (CSIC), Campus de Cantoblanco, Madrid 28049 (Spain)

    2009-08-15

    A high-sensitivity ac hysteresis loop tracer has been developed to measure the low frequency hysteresis loop of soft magnetic materials. It has been applied successfully to characterize straight pieces of amorphous glass-covered microwires with metallic nucleus down to 1.5 {mu}m thick. Based on the electromagnetic induction law, the proposed design is extremely simple and exploits the capabilities of commercially available data acquisition cards together with digital signal processing in order to achieve high-sensitivity without the need of expensive analog equipment.

  3. Assessment of daily exposure of endodontic personnel to extremely low frequency magnetic fields.

    Science.gov (United States)

    Kim, D W; Choi, J L; Kwon, M K; Nam, T J; Lee, S J

    2012-08-01

    To measure daily exposure levels to extremely low frequency magnetic fields (ELF MFs) in endodontic clinics. In total, 10 subjects (five endodontic trainees, five hygienists) participated. Each volunteer wore a 60-Hz MF measurement device on the left upper arm during working hours. Measurements were taken continuously throughout the working day except at lunch time. Separate measurements were taken for specific items of equipment at several distances. The average MF exposure for the 10 personnel was 0.03±0.04micro-Tesla (μT) (range, 0.01-6.4μT). The average MF exposure of endodontic personnel was lower than that of other hospital personnel according to the literature. Furthermore, all monitored exposure levels were well below the maximum acute exposure level, 500μT, recommended by the International Committee on Non-ionizing Radiation Protection for the protection of workers against ELF MFs. However, relatively high levels of exposure occurred in an operating room and X-ray room, presumably as a result of the use of surgical equipment such as microscopes and monitors, various motors and power cables of X-ray machines with large current flows. The total average MF exposure level of 0.03μT was lower than the typical background level at home. Although high levels of exposure were measured in an operating room and X-ray room, the MF exposure level to dental personnel was minimal during routine endodontic clinical work. © 2012 International Endodontic Journal.

  4. High-frequency magnetic components

    CERN Document Server

    Kazimierczuk, Marian K

    2013-01-01

    A unique text on the theory and design fundaments of inductors and transformers, updated with more coverage on the optimization of magnetic devices and many new design examples The first edition is popular among a very broad audience of readers in different areas of engineering and science. This book covers the theory and design techniques of the major types of high-frequency power inductors and transformers for a variety of applications, including switching-mode power supplies (SMPS) and resonant dc-to-ac power inverters and dc-to-dc power converters. It describes eddy-current phenomena (su

  5. Extremely High Current, High-Brightness Energy Recovery Linac

    CERN Document Server

    Ben-Zvi, Ilan; Beavis, Dana; Blaskiewicz, Michael; Bluem, Hans; Brennan, Joseph M; Burger, Al; Burrill, Andrew; Calaga, Rama; Cameron, Peter; Chang, Xiangyun; Cole, Michael; Connolly, Roger; Delayen, Jean R; Favale, Anthony; Gassner, David M; Grimes, Jacob T; Hahn, Harald; Hershcovitch, Ady; Holmes, Douglas; Hseuh Hsiao Chaun; Johnson, Peter; Kayran, Dmitry; Kewisch, Jorg; Kneisel, Peter; Lambiase, Robert; Litvinenko, Vladimir N; McIntyre, Gary; Meng, Wuzheng; Nehring, Thomas; Nicoletti, Tony; Oerter, Brian; Pate, David; Phillips, Larry; Preble, Joseph P; Rank, Jim; Rao, Triveni; Rathke, John; Roser, Thomas; Russo, Thomas; Scaduto, Joseph; Schultheiss, Tom; Segalov, Zvi; Smith, Kevin T; Todd, Alan M M; Warren-Funk, L; Williams, Neville; Wu, Kuo-Chen; Yakimenko, Vitaly; Yip, Kin; Zaltsman, Alex; Zhao, Yongxiang

    2005-01-01

    Next generation ERL light-sources, high-energy electron coolers, high-power Free-Electron Lasers, powerful Compton X-ray sources and many other accelerators were made possible by the emerging technology of high-power, high-brightness electron beams. In order to get the anticipated performance level of ampere-class currents, many technological barriers are yet to be broken. BNL's Collider-Accelerator Department is pursuing some of these technologies for its electron cooling of RHIC application, as well as a possible future electron-hadron collider. We will describe work on CW, high-current and high-brightness electron beams. This will include a description of a superconducting, laser-photocathode RF gun and an accelerator cavity capable of producing low emittance (about 1 micron rms normalized) one nano-Coulomb bunches at currents of the order of one ampere average.

  6. Technical aspects of exposure to magnetic fields of extremely low frequencies (ELF in biomedical research

    Directory of Open Access Journals (Sweden)

    Paweł Bieńkowski

    2015-06-01

    Full Text Available Background: Experiments on the electromagnetic field influence on organisms are an important part of biophysical studies. It is an interdisciplinary research spanning biology and medicine with the engineering in generation and measurement of electromagnetic fields. The aim of the study consists in the analysis of parameters estimations and measurements of extremely low frequency magnetic field (ELF MF as well as exposure systems parameters in biomedical research. Material and Methods: Experiments were performed on 2 most popular low magnetic field exposure systems: the solenoid and Helmholtz coils. A theoretical analysis and a measurement verification of the magnetic field distribution inside the systems were carried out to evaluate the homogeneity of the magnetic field. Additional factors, vibrations and temperature changes, affecting the assessment of the biological effects of magnetic field exposure were also examined. Results: Based on the study results, a comparative analysis of solenoids and Helmholtz coils as the magnetic field exposure systems was presented. Proposals for the description of magnetic field exposure were also formulated. Conclusions: The authors emphasize the importance of a conscious choice of exposure conditions and their explicit description. These are fundamental requirements for both the reproduction of experimental conditions and the verification of results. Med. Pr. 2015;66(2:185–197

  7. Magnetic resonance imaging of acute 'wiiitis' of the upper extremity

    Energy Technology Data Exchange (ETDEWEB)

    Nett, Michael P.; Sperling, John W. [Mayo Clinic, Department of Orthopedic Surgery, Rochester, MN (United States); Collins, Mark S. [Mayo Clinic, Department of Radiology, Rochester, MN (United States)

    2008-05-15

    We present the first reported case of acute 'wiiitis', documented clinically and by imaging, of the upper extremity, caused by prolonged participation in a physically interactive virtual video-game. Unenhanced magnetic resonance imaging (MRI) demonstrated marked T2-weighted signal abnormality within several muscles of the shoulder and upper arm, without evidence of macroscopic partial- or full-thickness tearing of the muscle or of intramuscular hematoma. (orig.)

  8. Application of Advanced Magnetic Resonance Imaging Techniques in Evaluation of the Lower Extremity

    Science.gov (United States)

    Braun, Hillary J.; Dragoo, Jason L.; Hargreaves, Brian A.; Levenston, Marc E.; Gold, Garry E.

    2012-01-01

    Synopsis This article reviews current magnetic resonance imaging techniques for imaging the lower extremity, focusing on imaging of the knee, ankle, and hip joints. Recent advancements in MRI include imaging at 7 Tesla, using multiple receiver channels, T2* imaging, and metal suppression techniques, allowing more detailed visualization of complex anatomy, evaluation of morphological changes within articular cartilage, and imaging around orthopedic hardware. PMID:23622097

  9. Magnetic hyperbolic metamaterial of high-index nanowires

    Science.gov (United States)

    Mirmoosa, M. S.; Kosulnikov, S. Yu.; Simovski, C. R.

    2016-08-01

    We show that the axial component of the magnetic permeability tensor is resonant for a wire medium consisting of high-index epsilon-positive nanowires, and its real part changes the sign at a certain frequency. At this frequency the medium experiences the topological phase transition between the elliptic and hyperbolic type of dispersion. We show that the transition regime is characterized by an extremely strong dependence of the permeability on the wave vector. This implies very high density of electromagnetic states that results in the filamentary pattern and noticeable Purcell factor for a transversely oriented magnetic dipole.

  10. Children’s Personal Exposure Measurements to Extremely Low Frequency Magnetic Fields in Italy

    Directory of Open Access Journals (Sweden)

    Ilaria Liorni

    2016-05-01

    Full Text Available Extremely low frequency magnetic fields (ELF-MFs exposure is still a topic of concern due to their possible impact on children’s health. Although epidemiological studies claimed an evidence of a possible association between ELF-MF above 0.4 μT and childhood leukemia, biological mechanisms able to support a causal relationship between ELF-MF and this disease were not found yet. To provide further knowledge about children’s ELF-MF exposure correlated to children’s daily activities, a measurement study was conducted in Milan (Italy. Eighty-six children were recruited, 52 of whom were specifically chosen with respect to the distance to power lines and built-in transformers to oversample potentially highly exposed children. Personal and bedroom measurements were performed for each child in two different seasons. The major outcomes of this study are: (1 median values over 24-h personal and bedroom measurements were <3 μT established by the Italian law as the quality target; (2 geometric mean values over 24-h bedroom measurements were mostly <0.4 μT; (3 seasonal variations did not significantly influence personal and bedroom measurements; (4 the highest average MF levels were mostly found at home during the day and outdoors; (5 no significant differences were found in the median and geometric mean values between personal and bedroom measurements, but were found in the arithmetic mean.

  11. Children's Personal Exposure Measurements to Extremely Low Frequency Magnetic Fields in Italy.

    Science.gov (United States)

    Liorni, Ilaria; Parazzini, Marta; Struchen, Benjamin; Fiocchi, Serena; Röösli, Martin; Ravazzani, Paolo

    2016-05-31

    Extremely low frequency magnetic fields (ELF-MFs) exposure is still a topic of concern due to their possible impact on children's health. Although epidemiological studies claimed an evidence of a possible association between ELF-MF above 0.4 μT and childhood leukemia, biological mechanisms able to support a causal relationship between ELF-MF and this disease were not found yet. To provide further knowledge about children's ELF-MF exposure correlated to children's daily activities, a measurement study was conducted in Milan (Italy). Eighty-six children were recruited, 52 of whom were specifically chosen with respect to the distance to power lines and built-in transformers to oversample potentially highly exposed children. Personal and bedroom measurements were performed for each child in two different seasons. The major outcomes of this study are: (1) median values over 24-h personal and bedroom measurements were values over 24-h bedroom measurements were mostly personal and bedroom measurements; (4) the highest average MF levels were mostly found at home during the day and outdoors; (5) no significant differences were found in the median and geometric mean values between personal and bedroom measurements, but were found in the arithmetic mean.

  12. Intergalactic Magnetic Fields and Gamma Ray Observations of Extreme TeV Blazars

    CERN Document Server

    Arlen, Timothy C; Weisgarber, Thomas; Wakely, Scott P; Shafi, S Yusef

    2012-01-01

    The intergalactic magnetic field (IGMF) can be indirectly probed through its effect on electromagnetic cascades initiated by a source of TeV gamma-rays, such as active galactic nuclei (AGN). AGN that are sufficiently luminous at TeV energies, extreme TeV blazars, can produce detectable levels of secondary radiation from Inverse Compton (IC) scattering of the electrons in the cascade, provided that the IGMF is not too large. We review recent work in the literature which utilizes this idea to derive constraints on the IGMF for three TeV-detected blazars-1ES 0229+200, 1ES 1218+304, and RGB J0710+591, and we also investigate four other hard-spectrum TeV blazars in the same context. Through a recently developed detailed Monte Carlo code, incorporating all major effects of QED and cosmological expansion, we research effects of major uncertainties such as the spectral properties of the source, uncertainty in the UV - far IR extragalactic background light (EBL), undersampled Very High Energy (VHE; energy > 100 GeV) c...

  13. Children’s Personal Exposure Measurements to Extremely Low Frequency Magnetic Fields in Italy

    Science.gov (United States)

    Liorni, Ilaria; Parazzini, Marta; Struchen, Benjamin; Fiocchi, Serena; Röösli, Martin; Ravazzani, Paolo

    2016-01-01

    Extremely low frequency magnetic fields (ELF-MFs) exposure is still a topic of concern due to their possible impact on children’s health. Although epidemiological studies claimed an evidence of a possible association between ELF-MF above 0.4 μT and childhood leukemia, biological mechanisms able to support a causal relationship between ELF-MF and this disease were not found yet. To provide further knowledge about children’s ELF-MF exposure correlated to children’s daily activities, a measurement study was conducted in Milan (Italy). Eighty-six children were recruited, 52 of whom were specifically chosen with respect to the distance to power lines and built-in transformers to oversample potentially highly exposed children. Personal and bedroom measurements were performed for each child in two different seasons. The major outcomes of this study are: (1) median values over 24-h personal and bedroom measurements were <3 μT established by the Italian law as the quality target; (2) geometric mean values over 24-h bedroom measurements were mostly <0.4 μT; (3) seasonal variations did not significantly influence personal and bedroom measurements; (4) the highest average MF levels were mostly found at home during the day and outdoors; (5) no significant differences were found in the median and geometric mean values between personal and bedroom measurements, but were found in the arithmetic mean. PMID:27258295

  14. Extremely low frequency magnetic field measurements in buildings with transformer stations in Switzerland.

    Science.gov (United States)

    Röösli, Martin; Jenni, Daniela; Kheifets, Leeka; Mezei, Gabor

    2011-08-15

    The aim of this study was to evaluate an exposure assessment method that classifies apartments in three exposure categories of extremely low frequency magnetic fields (ELF-MF) based on the location of the apartment relative to the transformer room. We completed measurements in 39 apartments in 18 buildings. In each room of the apartments ELF-MF was concurrently measured with 5 to 6 EMDEX II meters for 10 min. Measured arithmetic mean ELF-MF was 0.59 μT in 8 apartments that were fully adjacent to a transformer room, either directly above the transformer or touching the transformer room wall-to-wall. In apartments that only partly touched the transformer room at corners or edges, average ELF-MF level was 0.14 μT. Average exposure in the remaining apartments was 0.10 μT. Kappa coefficient for exposure classification was 0.64 (95%-CI: 0.45-0.82) if only fully adjacent apartments were considered as highly exposed (>0.4 μT). We found a distinct ELF-MF exposure gradient in buildings with transformer. Exposure classification based on the location of the apartment relative to the transformer room appears feasible. Such an approach considerably reduces effort for exposure assessment and may be used to eliminate selection bias in future epidemiologic studies.

  15. Characteristics of extreme ultraviolet emission from high-Z plasmas

    Science.gov (United States)

    Ohashi, H.; Higashiguchi, T.; Suzuki, Y.; Kawasaki, M.; Suzuki, C.; Tomita, K.; Nishikino, M.; Fujioka, S.; Endo, A.; Li, B.; Otsuka, T.; Dunne, P.; O'Sullivan, G.

    2016-03-01

    We demonstrate the extreme ultraviolet (EUV) and soft x-ray sources in the 2 to 7 nm spectral region related to the beyond EUV (BEUV) question at 6.x nm and the water window source based on laser-produced high-Z plasmas. Resonance emission from multiply charged ions merges to produce intense unresolved transition arrays (UTAs), extending below the carbon K edge (4.37 nm). An outline of a microscope design for single-shot live cell imaging is proposed based on high-Z plasma UTA source, coupled to multilayer mirror optics.

  16. Solidification at the High and Low Rate Extreme

    Energy Technology Data Exchange (ETDEWEB)

    Meco, Halim [Iowa State Univ., Ames, IA (United States)

    2004-12-19

    The microstructures formed upon solidification are strongly influenced by the imposed growth rates on an alloy system. Depending on the characteristics of the solidification process, a wide range of growth rates is accessible. The prevailing solidification mechanisms, and thus the final microstructure of the alloy, are governed by these imposed growth rates. At the high rate extreme, for instance, one can have access to novel microstructures that are unattainable at low growth rates. While the low growth rates can be utilized for the study of the intrinsic growth behavior of a certain phase growing from the melt. Although the length scales associated with certain processes, such as capillarity, and the diffusion of heat and solute, are different at low and high rate extremes, the phenomena that govern the selection of a certain microstructural length scale or a growth mode are the same. Consequently, one can analyze the solidification phenomena at both high and low rates by using the same governing principles. In this study, we examined the microstructural control at both low and high extremes. For the high rate extreme, the formation of crystalline products and factors that control the microstructure during rapid solidification by free-jet melt spinning are examined in Fe-Si-B system. Particular attention was given to the behavior of the melt pool at different quench-wheel speeds. Since the solidification process takes place within the melt-pool that forms on the rotating quench-wheel, we examined the influence of melt-pool dynamics on nucleation and growth of crystalline solidification products and glass formation. High-speed imaging of the melt-pool, analysis of ribbon microstructure, and measurement of ribbon geometry and surface character all indicate upper and lower limits for melt-spinning rates for which nucleation can be avoided, and fully amorphous ribbons can be achieved. Comparison of the relevant time scales reveals that surface-controlled melt

  17. Forecasting extreme wave events in moderate and high sea states

    Science.gov (United States)

    Magnusson, Anne Karin; Reistad, Magnar; Bitner-Gregersen, Elzbieta Maria

    2013-04-01

    Empirical studies on measurements have not yet come to conclusive relations between occurrence of rogue waves and - parameters which could be forecasted . Theoretical and tank experiments have demonstrated that high spectral peakedness and low spectral width combined (high Benjamin-Feir instability index, Onorato et al., 2006) give higher probability of rogue wave occurrence. Directional spread seems to reduce the probability of occurrence of rogue waves in these studies. Many years of experience with forecasting and discussions with people working in ocean environment indicate that rogue waves may as well occur in crossing seas. This was also indicated in a study in the Maxwave project (Toffoli et al., 2003) and the EXTREME SEAS project (Toffoli et al., 2011). We have here experimented with some indexes describing both high BFI and crossing seas and run the WAM model for some North Sea storm cases. Wave distributions measured at Ekofisk are analysed in the different cases. References • Onorato, M., Osborne, A., Serio, M., Cavaleri, L., Brandini, C., and Stansberg, C.: Extreme waves, modulational instability and second order theory: wave flume experiments on irregular waves,Europ. J. Mech. B/Fluids, 25, 586-601, 2006. • Toffoli, A., Lefevre, J.M., Monbaliu, J., Savina, H., and Bitner-Gregersen, E., "Freak Waves:Clues for Prediction in Ship Accidents?", Proc. ISOPE'2003 Conf. Hawai, USA, 2003. • Toffoli A., Bitner-Gregersen E. M., Osborne A. R., Serio M. Monbaliu J., Onorato M. (2011) Extreme Waves in Random Crossing Seas: Laboratory Experiments and Numerical Simulations. Geophys. Res. Lett., Vol. 38, L06605, 5 pp. doi: 10.1029/2011.

  18. SQUID holder with high magnetic shielding

    Science.gov (United States)

    Rigby, K. W.; Marek, D.; Chui, T. C. P.

    1990-01-01

    A SQUID holder designed for high magnetic shielding is discussed. It is shown how to estimate the attenuation of the magnetic field from the normal magnetic modes for an approximate geometry. The estimate agrees satisfactorily with the attenuation measured with a commercial RF SQUID installed in the holder. The holder attenuates external magnetic fields by more than 10 to the 9th at the SQUID input. With the SQUID input shorted, the response to external fields is 0.00001 Phi(0)/G.

  19. Extremely low-frequency magnetic fields of transformers and possible biological and health effects.

    Science.gov (United States)

    Sirav, Bahriye; Sezgin, Gaye; Seyhan, Nesrin

    2014-12-01

    Physiological processes in organisms can be influenced by extremely low-frequency (ELF) electromagnetic energy. Biological effect studies have great importance; as well as measurement studies since they provide information on the real exposure situations. In this study, the leakage magnetic fields around a transformer were measured in an apartment building in Küçükçekmece, Istanbul, and the measurement results were evaluated with respect to the international exposure standards. The transformer station was on the bottom floor of a three-floor building. It was found that people living and working in the building were exposed to ELF magnetic fields higher than the threshold magnetic field value of the International Agency for Research on Cancer (IARC). Many people living in this building reported health complaints such as immunological problems of their children. There were child-workers working in the textile factories located in the building. Safe distances or areas for these people should be recommended. Protective measures could be implemented to minimize these exposures. Further residential exposure studies are needed to demonstrate the exposure levels of ELF magnetic fields. Precautions should, therefore, be taken either to reduce leakage or minimize the exposed fields. Shielding techniques should be used to minimize the leakage magnetic fields in such cases.

  20. Selected studies of magnetism at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Hearne, G.R. [University of the Witwatersrand, Johannesburg (South Africa). Dept. of Physics; Pasternak, M.P. [Tel-Aviv Univ. (Israel). School of Physics and Astronomy; Taylor, R.D. [Los Alamos National Lab., NM (United States)

    1995-09-01

    Most previous studies of magnetism in various compounds under extreme conditions have been conducted over a wide pressure range at room temperature or over a wide range of cryogenic temperatures at pressures below 20 GPa (200 kbar). We present some of the most recent studies of magnetism over an extended range of temperatures and pressures far beyond 20 GPa, i.e., in regions of pressure-temperature (P-T) where magnetism has been largely unexplored. Recent techniques have permitted investigations of magnetism in selected 3d transition metal compounds in regions of P-T where physical properties may be drastically modified; related effects have often been seen in selected doping studies at ambient pressures.

  1. Magnetic properties of zero-magnetostrictive nanocrystalline Fe-Zr-Nb-B soft magnetic alloys with high magnetic induction

    Energy Technology Data Exchange (ETDEWEB)

    Makino, A.; Bitoh, T. E-mail: teruo_bitoh@akita-pu.ac.jp; Kojima, A.; Inoue, A.; Masumoto, T

    2000-06-02

    The soft magnetic properties of the nanocrystalline Fe-Zr-Nb-B alloys have been investigated. The best soft magnetic properties have been obtained for the Fe{sub 85.5}Zr{sub 2}Nb{sub 4}B{sub 8.5} alloy. The alloy shows a high permeability of 60,000 at 1 kHz, a high magnetic induction of 1.64 T and zero magnetostriction, simultaneously. The alloy also exhibits a very low core loss of 0.09 W/kg at 1.4 T and 50 Hz, which is extremely lower than that of Fe-Si-B amorphous. The nanocrystalline Fe-Zr-Nb-B alloy is therefore suitable for a core material for pole transformers.

  2. The effects of extremely low frequency magnetic fields on mutation induction in mice

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, James W. [Department of Genetics, University of Leicester, Leicester LE1 7RH (United Kingdom); Haines, Jackie; Sienkiewicz, Zenon [Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 0RQ (United Kingdom); Dubrova, Yuri E., E-mail: yed2@le.ac.uk [Department of Genetics, University of Leicester, Leicester LE1 7RH (United Kingdom)

    2015-03-15

    Highlights: • The effects of 50 Hz magnetic fields on mutation induction in mice were analyzed. • The frequency of ESTR mutation was established in sperm and blood. • Exposure to 10–300 μT for 2 and 15 h did not result in mutation induction. • Mutagenic effects of 50 Hz magnetic fields are likely to be negligible. - Abstract: The growing human exposure to extremely low frequency (ELF) magnetic fields has raised a considerable concern regarding their genotoxic effects. The aim of this study was to evaluate the in vivo effects of ELF magnetic fields irradiation on mutation induction in the germline and somatic tissues of male mice. Seven week old BALB/c × CBA/Ca F{sub 1} hybrid males were exposed to 10, 100 or 300 μT of 50 Hz magnetic fields for 2 or 15 h. Using single-molecule PCR, the frequency of mutation at the mouse Expanded Simple Tandem Repeat (ESTR) locus Ms6-hm was established in sperm and blood samples of exposed and matched sham-treated males. ESTR mutation frequency was also established in sperm and blood samples taken from male mice exposed to 1 Gy of acute X-rays. The frequency of ESTR mutation in DNA samples extracted from blood of mice exposed to magnetic fields did not significantly differ from that in sham-treated controls. However, there was a marginally significant increase in mutation frequency in sperm but this was not dose-dependent. In contrast, acute exposure X-rays led to significant increases in mutation frequency in sperm and blood of exposed males. The results of our study suggest that, within the range of doses analyzed here, the in vivo mutagenic effects of ELF magnetic fields are likely to be minor if not negligible.

  3. Magnetic resonance imaging of soft-tissue tumors of the extremities: A practical approach

    Institute of Scientific and Technical Information of China (English)

    Wing; P; Chan

    2013-01-01

    Diagnosis of extremity soft-tissue tumors can be challenging.Characteristics of tumor margins can help precisely identify locally aggressive or non-aggressive behavior for surgical planning,but cannot differentiate benign from malignant lesions.Most malignant tumors can have inhomogeneous signals on T2-weighted images.Although a uniform signal on T2-weighted images can be a reliable indication of a benign lesion,a well-defined mass with homogeneous internal signal intensity does not definitively identify a benign lesion.Some common and distinctive soft-tissue lesions can have specific clinical and imaging features allowing a diagnosis without biopsy.These are known as determinate lesions.This illustrative report presents a diagnostic guide for extremity soft-tissue tumors based on tissue signal and morphological characteristics on magnetic resonance images.It is important for clinicians to be familiar with the imaging characteristics of common determinate lesions.

  4. Quench in high temperature superconductor magnets

    CERN Document Server

    Schwartz, J

    2013-01-01

    High field superconducting magnets using high temperature superconductors are being developed for high energy physics, nuclear magnetic resonance and energy storage applications. Although the conductor technology has progressed to the point where such large magnets can be readily envisioned, quench protection remains a key challenge. It is well-established that quench propagation in HTS magnets is very slow and this brings new challenges that must be addressed. In this paper, these challenges are discussed and potential solutions, driven by new technologies such as optical fiber based sensors and thermally conducting electrical insulators, are reviewed.

  5. High magnetic fields science and technology

    CERN Document Server

    Miura, Noboru

    2003-01-01

    This three-volume book provides a comprehensive review of experiments in very strong magnetic fields that can only be generated with very special magnets. The first volume is entirely devoted to the technology of laboratory magnets: permanent, superconducting, high-power water-cooled and hybrid; pulsed magnets, both nondestructive and destructive (megagauss fields). Volumes 2 and 3 contain reviews of the different areas of research where strong magnetic fields are an essential research tool. These volumes deal primarily with solid-state physics; other research areas covered are biological syst

  6. Occupational exposure to extremely low-frequency magnetic fields and risk for central nervous system disease

    DEFF Research Database (Denmark)

    Pedersen, Camilla; Poulsen, Aslak Harbo; Rod, Naja Hulvej

    2017-01-01

    Purpose: Evidence of whether exposure to extremely low-frequency magnetic fields (ELF-MF) is related to central nervous system diseases is inconsistent. This study updates a previous study of the incidence of such diseases in a large cohort of Danish utility workers by almost doubling the period...... of exposure (≥1.0 µT), IRRs of 1.44, 1.78, 1.40 and 1.34 were observed for dementia, motor neurone disease, multiple sclerosis and epilepsy, respectively. Conclusions: We observed elevated risks of dementia, motor neurone disease, multiple sclerosis and epilepsy and lower risks of Parkinson disease...

  7. Treatment algorithms for high-energy traumas of lower extremities

    Directory of Open Access Journals (Sweden)

    Jovanović Mladen

    2002-01-01

    Full Text Available Introduction High-energy traumas are open or closed injuries caused by force (missile, traffic injuries, crush or blust injuries, falling from heights, affecting the body surface and transferring high amount of kinetic energy inducing great damage to the tissue. Management of such lower extremity injuries has evolved over past several decades, but still remains a difficult task for every surgical team. Specific anatomic and functional characteristics combined with extensive injuries demands specific treatment protocols. Multiple injuries In a multiple injured patient the first priority is management of life-threatening trauma. Despite other injuries, surgical treatment of limb-threatening injuries must start as soon as life-threatening condition has been managed. Treatment algorithms Algorithms are especially beneficial in management of severely injured, but salvageable extremities and in making decision on amputation. Insight into mechanisms of injury, as well as systematic examination of the affected limb, should help us understand the extensiveness of trauma and make an adequate management plan. Prevention of infection and surgical approach Prevention of wound infection and surgical approach to high- energy limb trauma, which includes wound extension, wound excision, skeletal stabilization and if necessary muscle compartment release, should be done in the first 6 hours after injury. Methods of soft tissue reconstruction Commonly used methods for soft tissue defects must provide wound coverage in less than five days following injury. Rehabilitation Early passive and active mobilization and verticalization of patients is very important for successful treatment. Conclusion Good and timely evaluation of the injured and collaboration between plastic and orthopedic surgeons from the beginning of treatment, are crucial for final outcome.

  8. Relay transport of relativistic flows in extreme magnetic fields of stars

    Science.gov (United States)

    Yao, W. P.; Qiao, B.; Xu, Z.; Zhang, H.; Chang, H. X.; Zhou, C. T.; Zhu, S. P.; Wang, X. G.; He, X. T.

    2017-08-01

    We find that the transport of relativistic flows in extreme magnetic fields can be achieved in a relay manner by considering the quantum electromagnetic cascade process, where photons play a key role as a medium. During the transport, the flow emits particle energy into photons via quantum synchrotron radiation, and then gains particles back by magnetic pair creation, forming a "particle-photon-particle" relay. Particle-in-cell simulations demonstrate that forward transport of the flow density is realized by a self-replenishment process with photon-pair cascades, while that of the flow energy is accomplished due to a new coupling path through radiation of photons. This novel transport mechanism is closely associated with jet generation and disk accretion around the neutron star of X-Ray Binaries, offering a potential explanation for the powerful jets observed there.

  9. Effects of Extremely Low Frequency Magnetic Field on the Lens of the Rats

    Directory of Open Access Journals (Sweden)

    Uğur Keklikçi

    2008-12-01

    Full Text Available The present aim of the study is to evaluate the effects of extremely low frequency magnetic field (ELF MF on lens epithelial cells. Twenty adult female Spraque Dawley rats were divided into two groups, each containing 10 rats. The experimental group received magnetic field 2 hours/day for 7 days. The second group receiving standard laboratory care, was used as a control. The specimens were evaluated for cataractogenesis alteretion of lens and histological changes in lens epithelial cells.On biomicroscopic examination, no pathological damage to the lens was detected. In addition, on microscopic examination of materials in the controls, there were also no changes in lens fibrils and lens epithelial cells. In experimental group, however, only a slight pleomorphism was determined at the surface of epithelial cells.In the study, it is cocluded that ELF MF exposure do might not lead to histopathological alterations of the lens fibrils and lens epithelial cells.

  10. Highly Efficient Freestyle Magnetic Nanoswimmer.

    Science.gov (United States)

    Li, Tianlong; Li, Jinxing; Morozov, Konstantin I; Wu, Zhiguang; Xu, Tailin; Rozen, Isaac; Leshansky, Alexander M; Li, Longqiu; Wang, Joseph

    2017-08-09

    The unique swimming strategies of natural microorganisms have inspired recent development of magnetic micro/nanorobots powered by artificial helical or flexible flagella. However, as artificial nanoswimmers with unique geometries are being developed, it is critical to explore new potential modes for kinetic optimization. For example, the freestyle stroke is the most efficient of the competitive swimming strokes for humans. Here we report a new type of magnetic nanorobot, a symmetric multilinked two-arm nanoswimmer, capable of efficient "freestyle" swimming at low Reynolds numbers. Excellent agreement between the experimental observations and theoretical predictions indicates that the powerful "freestyle" propulsion of the two-arm nanorobot is attributed to synchronized oscillatory deformations of the nanorobot under the combined action of magnetic field and viscous forces. It is demonstrated for the first time that the nonplanar propulsion gait due to the cooperative "freestyle" stroke of the two magnetic arms can be powered by a plane oscillatory magnetic field. These two-arm nanorobots are capable of a powerful propulsion up to 12 body lengths per second, along with on-demand speed regulation and remote navigation. Furthermore, the nonplanar propulsion gait powered by the consecutive swinging of the achiral magnetic arms is more efficient than that of common chiral nanohelical swimmers. This new swimming mechanism and its attractive performance opens new possibilities in designing remotely actuated nanorobots for biomedical operation at the nanoscale.

  11. Magnetic resonance angiographic assessment of upper extremity vessels prior to vascular access surgery: feasibility and accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Planken, Nils R. [Maastricht University Hospital, Department of Vascular Surgery, Maastricht (Netherlands); Maastricht University Hospital, Department of Radiology, Maastricht (Netherlands); Maastricht University Medical School, Cardiovascular Research Institute Maastricht, Maastricht (Netherlands); Tordoir, Jan H. [Maastricht University Hospital, Department of Vascular Surgery, Maastricht (Netherlands); Maastricht University Medical School, Cardiovascular Research Institute Maastricht, Maastricht (Netherlands); Duijm, Lucien E.; Bosch, Harrie C. van den [Catharina Hospital, Department of Radiology, Eindhoven (Netherlands); Sande, Frank M. van der; Kooman, Jeroen P. [Maastricht University Hospital, Department of Nephrology, Maastricht (Netherlands); Maastricht University Medical School, Cardiovascular Research Institute Maastricht, Maastricht (Netherlands); Haan, Michiel W. de; Leiner, Tim [Maastricht University Hospital, Department of Radiology, Maastricht (Netherlands); Maastricht University Medical School, Cardiovascular Research Institute Maastricht, Maastricht (Netherlands)

    2008-01-15

    A contrast-enhanced magnetic resonance angiography (CE-MRA) protocol for selective imaging of the entire upper extremity arterial and venous tree in a single exam has been developed. Twenty-five end-stage renal disease (ESRD) patients underwent CE-MRA and duplex ultrasonography (DUS) of the upper extremity prior to hemodialysis vascular access creation. Accuracy of CE-MRA arterial and venous diameter measurements were compared with DUS and intraoperative (IO) diameter measurements, the standard of reference. Upper extremity vasculature depiction was feasible with CE-MRA. CE-MRA forearm and upper arm arterial diameters were 2.94 {+-} 0.67 mm and 4.05 {+-} 0.84 mm, respectively. DUS arterial diameters were 2.80 {+-} 0.48 mm and 4.38 {+-} 1.24 mm; IO diameters were 3.00 {+-} 0.35 mm and 3.55 {+-} 0.51 mm. Forearm arterial diameters were accurately determined with both techniques. Both techniques overestimated upper arm arterial diameters significantly. Venous diameters were accurately determined with CE-MRA but not with DUS (forearm: CE-MRA: 2.64 {+-} 0.61 mm; DUS: 2.50 {+-} 0.44 mm, and IO: 3.40 {+-} 0.22 mm; upper arm: CE-MRA: 4.09 {+-} 0.71 mm; DUS: 3.02 {+-} 1.65 mm, and IO: 4.30 {+-} 0.78 mm). CE-MRA enables selective imaging of upper extremity vasculature in patients requiring hemodialysis access. Forearm arterial diameters can be assessed accurately by CE-MRA. Both CE-MRA and DUS slightly overestimate upper arm arterial diameters. In comparison to DUS, CE-MRA enables a more accurate determination of upper extremity venous diameters. (orig.)

  12. Experimental studies on extremely low frequency pulsed magnetic field inhibiting sarcoma and enhancing cellular immune functions

    Institute of Scientific and Technical Information of China (English)

    张沪生; 叶晖; 张传清; 曾繁清; 黄兴鼎; 张晴川; 李宗山; 杜碧

    1997-01-01

    The previous observation with an electron microscope showed that extremely low frequency (ELF) pulsed magnetic field (PMF) (with the maximum intensity of 0. 6-2. 0 T, gradient of 10-100 T. M-1, pulse width of 20-200 ms and frequency of 0. 16-1. 34 Hz) inhibited the growth of S-180 sarcoma in mice and enhanced the ability of immune cell’s dissolving sarcoma cells. In this study, the DNA contents of nuclei were assayed by using Faulgen Staining method. With an electron microscope and cell stereoscopy technology it was observed that magnetic field affected the sarcoma cell’s metabolism, lowered its malignancy, and restrained its rapid and heteromorphic growth. The magnetic field enhanced the cellular immune ability and the reaction of lymphocytes and plasma. Since ELF pulsed magnetic fields can inhibit the growth of sarcomas and enhance the cellular immune ability, it is possible to use it as a new method to treat cancer.

  13. Ptychographic hyperspectral spectromicroscopy with an extreme ultraviolet high harmonic comb

    CERN Document Server

    Zhang, Bosheng; Seaberg, Matthew H; Shanblatt, Elisabeth R; Porter, Christina L; Karl,, Robert; Mancuso, Christopher A; Kapteyn, Henry C; Murnane, Margaret M; Adams, Daniel E

    2016-01-01

    We demonstrate a new scheme of spectromicroscopy in the extreme ultraviolet (EUV) spectral range, where the spectral response of the sample at different wavelengths is imaged simultaneously. It is enabled by applying ptychographical information multiplexing (PIM) to a tabletop EUV source based on high harmonic generation, where four spectrally narrow harmonics near 30 nm form a spectral comb structure. Extending PIM from previously demonstrated visible wavelengths to the EUV/X-ray wavelengths promises much higher spatial resolution and more powerful spectral contrast mechanism, making PIM an attractive spectromicroscopy method in both the microscopy and the spectroscopy aspects. Besides the sample, the multicolor EUV beam is also imaged in situ, making our method a powerful beam characterization technique. No hardware is used to separate or narrow down the wavelengths, leading to efficient use of the EUV radiation.

  14. Magnetic microstructure and coercivity mechanism of high performance Nd-Fe-B magnets

    Institute of Scientific and Technical Information of China (English)

    ZHU Minggang; LIU Xingmin; FANG Yikun; LI Zhengbang; LI Wei

    2006-01-01

    Magnetic microstructure of high performance Nd-Fe-B magnets was investigated by using magnetic force microscopy. The correlation between magnetic microstructure and coercivity for high performance Nd-Fe-B magnets was studied. It is found that the magnets with different coercivity mechanism take on different microstructures and magnetism. Moreover, the magnetic microstructures of high performance permanent magnets can be explained by the starting field theory model.

  15. High-temperature superconductors in high-field magnets

    NARCIS (Netherlands)

    Weijers, Hubertus Wilhelmus

    2009-01-01

    The properties of both BSCCO conductors and YBCO coated conductors and coils are studied to assess their applicability in high-field magnets. First, the magnetic field dependence of the critical current density in these HTS conductors is measured at 4.2 K in magnetic field conditions ranging from s

  16. Occupational Exposure Assessment of Tehran Metro Drivers to Extremely Low Frequency Magnetic Fields

    Directory of Open Access Journals (Sweden)

    mohammad reza Monazzam

    2016-03-01

    Full Text Available Introduction: Occupational exposure to Extremely Low Frequency Magnetic Fields (ELF-MFs in train drivers is an integral part of the driving task and creates concern about driving jobs. The present study was designed to investigate the occupational exposure of Tehran train drivers to extremely low frequency magnetic fields. Methods: In order to measure the driver’s exposure, from each line, a random sample in AC and DC type trains was selected and measurements were done according to the IEEE std 644-1994 using a triple axis TES-394 device. Train drivers were then compared with national occupational exposure limit guidelines. Results: The maximum and minimum mean exposure was found in AC external city trains (1.2±1.5 μT and DC internal city trains (0.31±0.2 μT, respectively. The maximum and minimum exposure was 9 μT and 0.08 μT in AC trains of line 5, respectively. In the internal train line, maximum and minimum values were 5.4 μT and 0.08 μT in AC trains. Conclusions: In none of the exposure scenarios in different trains, the exposure exceeded the national or international occupational exposure limit guidelines. However, this should not be the basis of safety in these fields

  17. High Field Pulse Magnets with New Materials

    Science.gov (United States)

    Li, L.; Lesch, B.; Cochran, V. G.; Eyssa, Y.; Tozer, S.; Mielke, C. H.; Rickel, D.; van Sciver, S. W.; Schneider-Muntau, H. J.

    2004-11-01

    High performance pulse magnets using the combination of CuNb conductor and Zylon fiber composite reinforcement with bore sizes of 24, 15 and 10 mm have been designed, manufactured and tested to destruction. The magnets successfully reached the peak fields of 64, 70 and 77.8 T respectively with no destruction. Failures occurred near the end flanges at the layer. The magnet design, manufacturing and testing, and the mode of the failure are described and analyzed.

  18. Magnetic field topology and chemical spot distributions in the extreme Ap star HD 75049

    CERN Document Server

    Kochukhov, O; Valenti, J A; Stempels, H C; Snik, F; Rodenhuis, M; Piskunov, N; Makaganiuk, V; Keller, C U; Johns-Krull, C M

    2014-01-01

    Intermediate-mass, magnetic chemically peculiar (Ap) stars provide a unique opportunity to study the topology of stellar magnetic fields in detail and to investigate magnetically driven processes of spot formation. Here we aim to derive the surface magnetic field geometry and chemical abundance distributions for the extraordinary Ap star HD 75049. This object hosts a surface field of ~30 kG, one of the strongest known for any non-degenerate star. We used time-series of high-resolution HARPS intensity and circular polarisation observations. These data were interpreted with the help of magnetic Doppler imaging and model atmospheres incorporating effects of a non-solar chemical composition and a strong magnetic field. We refined the rotational period of HD 75049 to Prot=4.048267+/-0.000036 d. We also derived basic stellar parameters, Teff=10250+/-250 K and logg=4.3+/-0.1. Magnetic Doppler imaging revealed that the field topology of HD 75049 is poloidal and dominated by a dipolar contribution with a peak surface ...

  19. High photon flux table-top coherent extreme ultraviolet source

    CERN Document Server

    Hädrich, Steffen; Rothhardt, Jan; Krebs, Manuel; Hoffmann, Armin; Pronin, Oleg; Pervak, Vladimir; Limpert, Jens; Tünnermann, Andreas

    2014-01-01

    High harmonic generation (HHG) enables extreme ultraviolet radiation with table-top setups. Its exceptional properties, such as coherence and (sub)-femtosecond pulse durations, have led to a diversity of applications. Some of these require a high photon flux and megahertz repetition rates, e.g. to avoid space charge effects in photoelectron spectroscopy. To date this has only been achieved with enhancement cavities. Here, we establish a novel route towards powerful HHG sources. By achieving phase-matched HHG of a megahertz fibre laser we generate a broad plateau (25 eV - 40 eV) of strong harmonics, each containing more than $10^{12}$ photons/s, which constitutes an increase by more than one order of magnitude in that wavelength range. The strongest harmonic (H25, 30 eV) has an average power of 143 $\\mu$W ($3\\cdot10^{13}$ photons/s). This concept will greatly advance and facilitate applications in photoelectron or coincidence spectroscopy, coherent diffractive imaging or (multidimensional) surface science.

  20. Small-scale characteristics of extremely high latitude aurora

    Directory of Open Access Journals (Sweden)

    J. A. Cumnock

    2009-09-01

    Full Text Available We examine 14 cases of an interesting type of extremely high latitude aurora as identified in the precipitating particles measured by the DMSP F13 satellite. In particular we investigate structures within large-scale arcs for which the particle signatures are made up of a group of multiple distinct thin arcs. These cases are chosen without regard to IMF orientation and are part of a group of 87 events where DMSP F13 SSJ/4 measures emissions which occur near the noon-midnight meridian and are spatially separated from both the dawnside and duskside auroral ovals by wide regions with precipitating particles typical of the polar cap. For 73 of these events the high-latitude aurora consists of a continuous region of precipitating particles. We focus on the remaining 14 of these events where the particle signatures show multiple distinct thin arcs. These events occur during northward or weakly southward IMF conditions and follow a change in IMF By. Correlations are seen between the field-aligned currents and plasma flows associated with the arcs, implying local closure of the FACs. Strong correlations are seen only in the sunlit hemisphere. The convection associated with the multiple thin arcs is localized and has little influence on the large-scale convection. This also implies that the sunward flow along the arcs is unrelated to the overall ionospheric convection.

  1. Extremely high-frequency micro-Doppler measurements of humans

    Science.gov (United States)

    Hedden, Abigail S.; Silvious, Jerry L.; Dietlein, Charles R.; Green, Jeremy A.; Wikner, David A.

    2014-05-01

    The development of sensors that are capable of penetrating smoke, dust, fog, clouds, and rain is critical for maintaining situational awareness in degraded visual environments and for providing support to the Warfighter. Atmospheric penetration properties, the ability to form high-resolution imagery with modest apertures, and available source power make the extremely high-frequency (EHF) portion of the spectrum promising for the development of radio frequency (RF) sensors capable of penetrating visual obscurants. Comprehensive phenomenology studies including polarization and backscatter properties of relevant targets are lacking at these frequencies. The Army Research Laboratory (ARL) is developing a fully-polarimetric frequency-modulated continuous-wave (FMCW) instrumentation radar to explore polarization and backscatter properties of in-situ rain, scattering from natural and man-made surfaces, and the radar cross section and micro-Doppler signatures of humans at EHF frequencies, specifically, around the 220 GHz atmospheric window. This work presents an overview of the design and construction of the radar system, hardware performance, data acquisition software, and initial results including an analysis of human micro-Doppler signatures.

  2. ELF electric and magnetic fields: Pacific Northwest Laboratory studies. [Extremely Low Frequency (ELF)

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, L.E.

    1992-06-01

    Studies have been conducted at Battelle, Pacific Northwest Laboratory, to examine extremely-low-frequency (ELF) electromagnetic fields for possible biological effects in animals. Three areas of investigation are reported here: (1) studies on the nervous system, including behavior and neuroendocrine function, (2) experiments on cancer development in animals, and (3) measurements of currents and electric fields induced in animal models by exposure to external magnetic fields. In behavioral experiments, rats have been shown to be responsive to ELF electric field exposure. Furthermore, experimental data indicate that short-term memory may be affected in albino rats exposed to combined ELF and static magnetic fields. Neuroendocrine studies have been conducted to demonstrate an apparent stress-related response in rats exposed to 60-Hz electric fields. Nighttime pineal melatonin levels have been shown to be significantly depressed in animals exposed to either electric or magnetic fields. A number of animal tumor models are currently under investigation to examine possible relationships between ELF exposure and carcinogenesis. Finally, theoretical and experimental measurements have been performed which form the basis for animals and human exposure comparisons.

  3. The Extreme Ultraviolet Deficit and Magnetically Arrested Accretion in Radio Loud Quasars

    CERN Document Server

    Punsly, Brian

    2014-01-01

    The Hubble Space Telescope composite quasar spectra presented in Telfer et al. show a significant deficit of emission in the extreme ultraviolet (EUV) for the radio loud component of the quasar population (RLQs), compared to the radio quiet component of the quasar population (RQQs). The composite quasar continuum emission between 1100 \\AA\\, and $\\sim$580 \\AA\\, is generally considered to be associated with the innermost regions of the accretion flow onto the central black hole. The deficit between 1100 \\AA\\, and 580 \\AA\\, in RLQs has a straightforward interpretation as a missing or a suppressed innermost region of local energy dissipation in the accretion flow. It is proposed that this can be the result of islands of large scale magnetic flux in RLQs that are located close to the central black hole that remove energy from the accretion flow as Poynting flux (sometimes called magnetically arrested accretion). These magnetic islands are natural sites for launching relativistic jets. Based on the Telfer et al. da...

  4. Homogenous BSCCO-2212 Round Wires for Very High Field Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Scott Campbell

    2012-06-30

    The performance demands on modern particle accelerators generate a relentless push towards higher field magnets. In turn, advanced high field magnet development places increased demands on superconducting materials. Nb3Sn conductors have been used to achieve 16 T in a prototype dipole magnet and are thought to have the capability for {approx}18 T for accelerator magnets (primarily dipoles but also higher order multipole magnets). However there have been suggestions and proposals for such magnets higher than 20 T. The High Energy Physics Community (HEP) has identified important new physics opportunities that are enabled by extremely high field magnets: 20 to 50 T solenoids for muon cooling in a muon collider (impact: understanding of neutrinos and dark matter); and 20+ T dipoles and quadrupoles for high energy hadron colliders (impact: discovery reach far beyond present). This proposal addresses the latest SBIR solicitation that calls for grant applications that seek to develop new or improved superconducting wire technologies for magnets that operate at a minimum of 12 Tesla (T) field, with increases up to 15 to 20 T sought in the near future (three to five years). The long-term development of accelerator magnets with fields greater than 20 T will require superconducting wires having significantly better high-field properties than those possessed by current Nb{sub 3}Sn or other A15 based wires. Given the existing materials science base for Bi-2212 wire processing, we believe that Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} (Bi-2212) round wires can be produced in km-long piece lengths with properties suitable to meet both the near term and long term needs of the HEP community. The key advance will be the translation of this materials science base into a robust, high-yield wire technology. While the processing and application of A15 materials have advanced to a much higher level than those of the copper oxide-based, high T{sub c} (HTS) counterparts, the HTS materials have

  5. Extreme particle acceleration in magnetic reconnection layers. Application to the gamma-ray flares in the Crab Nebula

    CERN Document Server

    Cerutti, Benoit; Begelman, Mitchell C

    2011-01-01

    The gamma-ray space telescopes AGILE and Fermi detected short and bright synchrotron gamma-ray flares at photon energies above 100 MeV in the Crab Nebula. This discovery suggests that electron-positron pairs in the nebula are accelerated to PeV energies in a mG magnetic field within a few days, which is difficult to explain with classical models of particle acceleration and pulsar wind nebulae. In this article, we investigate whether particle acceleration in a magnetic reconnection layer can account for the puzzling properties of the flares. We numerically integrate relativistic test-particle orbits in the vicinity of the layer, including the radiation reaction force, and using simple analytical expressions for the large-scale electromagnetic fields. As they get accelerated by the reconnection electric field, the particles are trapped and focused deep inside the current layer where the magnetic field is small. The electrons suffer less from synchrotron losses and are accelerated to extremely high energies. Po...

  6. NON-POTENTIAL FIELDS IN THE QUIET SUN NETWORK: EXTREME-ULTRAVIOLET AND MAGNETIC FOOTPOINT OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Chesny, D. L.; Oluseyi, H. M.; Orange, N. B. [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 (United States)

    2013-11-20

    The quiet Sun (QS) magnetic network is known to contain dynamics which are indicative of non-potential fields. Non-potential magnetic fields forming ''S-shaped'' loop arcades can lead to the breakdown of static activity and have only been observed in high temperature X-ray coronal structures—some of which show eruptive behavior. Thus, analysis of this type of atmospheric structuring has been restricted to large-scale coronal fields. Here we provide the first identification of non-potential loop arcades exclusive to the QS supergranulation network. High-resolution Atmospheric Imaging Assembly data from the Solar Dynamics Observatory have allowed for the first observations of fine-scale ''S-shaped'' loop arcades spanning the network. We have investigated the magnetic footpoint flux evolution of these arcades from Heliospheric and Magnetic Imager data and find evidence of evolving footpoint flux imbalances accompanying the formation of these non-potential fields. The existence of such non-potentiality confirms that magnetic field dynamics leading to the build up of helicity exist at small scales. QS non-potentiality also suggests a self-similar formation process between the QS network and high temperature corona and the existence of self-organized criticality (SOC) in the form of loop-pair reconnection and helicity dissipation. We argue that this type of behavior could lead to eruptive forms of SOC as seen in active region (AR) and X-ray sigmoids if sufficient free magnetic energy is available. QS magnetic network dynamics may be considered as a coronal proxy at supergranular scales, and events confined to the network can even mimic those in coronal ARs.

  7. CO2-Philic polymer membrane with extremely high separation performance

    KAUST Repository

    Yave, Wilfredo

    2010-01-12

    Polymeric membranes are attractive for CO2 separation and concentration from different gas streams because of their versatility and energy efficiency; they can compete with, and they may even replace, traditional absorption processes. Here we describe a simple and powerful method for developing nanostructured and CO2-philic polymer membranes for CO2 separation. A poly(ethylene oxide)-poly(butylene terephthalate) multiblock copolymer is used as membrane material. Smart additives such as polyethylene glycol dibutyl ether are incorporated as spacers or fillers for producing nanostructured materials. The addition of these specific additives produces CO2-philic membranes and increases the CO2 permeability (750 barrer) up to five-fold without the loss of selectivity. The membranes present outstanding performance for CO2 separation, and the measured CO2 flux is extremely high ( > 2 m3 m -2 h-1 bar-1) with selectivity over H2 and N2 of 10 and 40, respectively, making them attractive for CO 2 capture. © 2009 American Chemical Society.

  8. Synoptic conditions leading to extremely high temperatures in Madrid

    Directory of Open Access Journals (Sweden)

    R. García

    Full Text Available Extremely hot days (EHD in Madrid have been analysed to determine the synoptic patterns that produce EHDs during the period of 1955–1998. An EHD is defined as a day with maximum temperature higher than 36.5°C, a value which is the threshold for the intense effects on mortatility and it coincides with the 95 percentile of the series. Two different situations have been detected as being responsible for an EHD occurrence, one more dynamical, produced by southern fluxes, and another associated with a stagnation situation over Iberia of a longer duration. Both account for 92% of the total number of days, thus providing an efficient classification framework. A circulation index has been derived to characterise and forecast an EHD occurrence. This paper shows that EHD occur in Madrid during short duration events, and no long heat waves, like those recorded in other cities, are present. Additionally, no clear pattern can be detected in the EHD frequency; the occurrence is tied to changes in the summer location of the Azores high.

    Key words. Meteorology and atmospheric dynamics (Climatology; synoptic-scale meteorology; general or miscellaneous

  9. Extremely high-intensity laser interactions with fundamental quantum systems

    CERN Document Server

    Di Piazza, A; Hatsagortsyan, K Z; Keitel, C H

    2011-01-01

    The field of laser-matter interaction traditionally deals with the response of atoms, molecules and plasmas to an external light wave. However, the recent sustained technological progress is opening the possibility of employing intense laser radiation to prompt or substantially influence physical processes beyond atomic-physics energy scales. Available optical laser intensities exceeding $10^{22}\\;\\text{W/cm$^2$}$ can push the fundamental light-electron interaction to the extreme limit where radiation-reaction effects dominate the electron dynamics, can shed light on the structure of the quantum vacuum and can prime the creation of particles like electrons, muons and pions and the corresponding antiparticles. Also, novel sources of intense coherent high-energy photons and laser-based particle colliders can pave the way to nuclear quantum optics and can even allow for potential discovery of new particles beyond the Standard Model. These are the main topics of the present article, which is devoted to a review o...

  10. Synoptic conditions leading to extremely high temperatures in Madrid

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, R.; Prieto, L.; Hernandez, E.; Teso, T. del [Dept. Fisica de la Tierra II, Fac. CC. Fisicas, Univ. Camplutense de Madrid (Spain); Diaz, J. [Centro Universitario de Salud Publica, Univ. Autonoma de Madrid (Spain)

    2002-02-01

    Extremely hot days (EHD) in Madrid have been analysed to determine the synoptic patterns that produce EHDs during the period of 1955-1998. An EHD is defined as a day with maximum temperature higher than 36.5 C, a value which is the threshold for the intense effects on mortatility and it coincides with the 95 percentile of the series. Two different situations have been detected as being responsible for an EHD occurrence, one more dynamical, produced by southern fluxes, and another associated with a stagnation situation over Iberia of a longer duration. Both account for 92% of the total number of days, thus providing an efficient classification framework. A circulation index has been derived to characterise and forecast an EHD occurrence. This paper shows that EHD occur in Madrid during short duration events, and no long heat waves, like those recorded in other cities, are present. Additionally, no clear pattern can be detected in the EHD frequency; the occurrence is tied to changes in the summer location of the Azores high. (orig.)

  11. Construction of high magnetic field facilities approved

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ On 25 January, the National Development and Reform Commission gave the green light to a proposal to construct high magnetic field facilities for experimental use. The suggestion was jointly submitted by the Ministry of Education and CAS.

  12. Low-cost, low-field dedicated extremity magnetic resonance imaging in early rheumatoid arthritis

    DEFF Research Database (Denmark)

    Lindegaard, Hanne Merete; Valloe, J.; Hørslev-Petersen, K.

    2006-01-01

    with rheumatoid arthritis with joint symptoms for hands and wrists, and E-MRI of the dominant wrist and MCP joints. RESULTS: At baseline, all......OBJECTIVE: To study the ability of low-cost low-field dedicated extremity magnetic resonance imaging (E-MRI) to assess and predict erosive joint damage in the wrist and metacarpophalangeal (MCP) joints of patients with early rheumatoid arthritis. METHODS: 24 previously untreated patients...... were excluded, the relative risk was 5.2. In patients with baseline MRI bone erosion or oedema, the relative risk of having x ray erosions at 1 year was 4.0, compared with patients without these signs at baseline (patient-centred analysis). CONCLUSION: In this group of patients with early rheumatoid...

  13. Exposure to extremely low-frequency magnetic field affects biofilm formation by cystic fibrosis pathogens.

    Science.gov (United States)

    Di Bonaventura, Giovanni; Pompilio, Arianna; Crocetta, Valentina; De Nicola, Serena; Barbaro, Filippo; Giuliani, Livio; D'Emilia, Enrico; Fiscarelli, Ersilia; Bellomo, Rosa Grazia; Saggini, Raoul

    2014-01-01

    To evaluate the in vitro effects of extremely low-frequency magnetic field (ELF-MF) on growth and biofilm formation by Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia and Stenotrophomonas maltophilia strains from cystic fibrosis patients. The motion of selected ions (Fe, Ca, Cu, Zn, Mg, K, Na) was stimulated by the ion resonance effect, then influence on growth and biofilm formation/viability was assessed by spectrophotometry or viability count. Generally, exposure to ELF-MF significantly increased bacterial growth and affected both biofilm formation and viability, although with differences with regard to ions and species considered. Exposure to ELF-MF represents a possible new approach for treatment of biofilm-associated cystic fibrosis lung infections.

  14. Studies on Magnetization Technique of High Temperature Superconductors

    OpenAIRE

    大橋, 忠巌; 荻原, 宏康

    1999-01-01

    It is known that permanent magnets produce magnetic fields up to 1T. On the other hand, magnetized high temperature superconductors can be used as "super"-permanent magnets which produce magnetic fields higher than 1T, because superconductors can trap higher magnetic fluxes than usual permanent magnets. In order to magnetize a YBCO bulk superconductor, there are two ways; a field cooling (FC) method and a zero field cooling (ZFC) method. FC is the way of magnetizing the superconductor by appl...

  15. Dynamical instability of white dwarfs and breaking of spherical symmetry under the presence of extreme magnetic fields

    CERN Document Server

    Coelho, J G; Malheiro, M; Negreiros, R; Rueda, J A; Ruffini, R

    2013-01-01

    In this letter we discuss some basic properties of the equilibrium of magnetized white dwarfs, in particular the condition for dynamical instability of the star in the presence of an extremely large magnetic field. This will be done in the context of the virial theorem extended to include a magnetic term. We show, following the work of Chandrasekhar & Fermi of 1953, that when the star magnetic energy $W_B$ exceeds its gravitational potential energy $\\lvert W_G\\lvert$ ($W_B>\\lvert W_G\\lvert$), the system becomes dynamically unstable. In that seminal work it was shown that for extreme magnetic fields, a sphere is not the equilibrium configuration, and the star will become an oblate spheroid contracted along the symmetry axis. In light of this, the new mass limit for very magnetized and spherical white dwarf of 2.58$M_\\odot$, recently calculated, should be considered carefully, since these objects are unstable and unbound, and also because the extreme magnetic fields violate the spherical symmetry assumed to...

  16. The effect of extremely low frequency magnetic field on heart tissue iron density

    Directory of Open Access Journals (Sweden)

    Yusuf Nergiz

    2011-06-01

    Full Text Available The aim of this histological study was to investigate the effects of extremely low frequency, low intensity magnetic field on the heart muscle ıron density.Materials and methods: In this study, 45 male Spraque Dawley rats were introduced and were divided into three groups as sham, control and experiment group. The experimental group was exposed to a 0.25 mT to Extremely Low Frequency Magnetic Field (ELF-MF for 14 days, 3h a day in metacrylate boxes. The sham group was treated like the experimental group, except for ELF-MF exposure. For control, nothing applied to rats in this group and they completed their life cycle in the cage during the study period. After exposure period, the rats were sacrificed under ketalar anesthesia (50 mg / kg, intramuscularly. Heart tissues were immediately fixed in 10% neutral formaldehyde and embedded in paraffin blocks. Histological sections from cardiac tissue stained by hematoxylin-eosin, Perls’ Prussian blue for iron pigments. Histological slides were photographed under a Nikon DS-2MV photomicroscope.Results: The architecture and histology of the control, sham and experimental group were observed as normal. No differences were observed between the control, sham and experimental rat groups in the iron stain of heart tissues.Conclusion: As a result of our study, we did not observe differences between the control and ELF-MF (experimental group. In this investigation we demonstrated that the exposure of cardiac tissue of rats to the ELF-MF did not change in the iron stain study. J Clin Exp Invest 2011;2(2:144-8

  17. Extremely Low Frequency Magnetic Fields Induce Spermatogenic Germ Cell Apoptosis: Possible Mechanism

    Directory of Open Access Journals (Sweden)

    Sang-Kon Lee

    2014-01-01

    Full Text Available The energy generated by an extremely low frequency electromagnetic field (ELF-EMF is too weak to directly induce genotoxicity. However, it is reported that an extremely low frequency magnetic field (ELF-MF is related to DNA strand breakage and apoptosis. The testes that conduct spermatogenesis through a dynamic cellular process involving meiosis and mitosis seem vulnerable to external stress such as heat, MF exposure, and chemical or physical agents. Nevertheless the results regarding adverse effects of ELF-EMF on human or animal reproductive functions are inconclusive. According to the guideline of the International Commission on Non-Ionizing Radiation Protection (ICNIRP; 2010 for limiting exposure to time-varying MF (1 Hz to 100 kHz, overall conclusion of epidemiologic studies has not consistently shown an association between human adverse reproductive outcomes and maternal or paternal exposure to low frequency fields. In animal studies there is no compelling evidence of causal relationship between prenatal development and ELF-MF exposure. However there is increasing evidence that EL-EMF exposure is involved with germ cell apoptosis in testes. Biophysical mechanism by which ELF-MF induces germ cell apoptosis has not been established. This review proposes the possible mechanism of germ cell apoptosis in testes induced by ELF-MF.

  18. Anomalous dynamics of the extremely compressed magnetosphere during 21 January 2005 magnetic storm

    CERN Document Server

    Dmitriev, A V; Chao, J -K; Wang, C B; Rastaetter, L; Panasyuk, M I; Lazutin, L L; Kovtyukh, A S; Veselovsky, I S; Myagkova, I N

    2014-01-01

    Dynamics of the dayside magnetosphere and proton radiation belt was analyzed during unusual magnetic storm on 21 January 2005. We have found that during the storm from 1712 to 2400 UT, the subsolar magnetopause was continuously located inside geosynchronous orbit due to strong compression. The compression was found to be extremely strong from 1846 to 2035 UT when the dense plasma of fast erupting filament produced the solar wind dynamic pressure Pd peaked up to >100 nPa and, in the first time, the upstream solar wind was observed at geosynchronous orbit during almost 2 hours. Under the extreme compression, the outer magnetosphere at L > 5 was pushed inward and the outer radiation belt particles with energies of several tens of keV moved earthward, became adiabatically accelerated and accumulated in the inner magnetosphere at L 20%, which is well appropriate for erupting filaments and which is in agreement with the upper 27% threshold for the He/H ratio obtained from Cluster measurements.

  19. Credible occurrence probabilities for extreme geophysical events: earthquakes, volcanic eruptions, magnetic storms

    Science.gov (United States)

    Love, Jeffrey J.

    2012-01-01

    Statistical analysis is made of rare, extreme geophysical events recorded in historical data -- counting the number of events $k$ with sizes that exceed chosen thresholds during specific durations of time $\\tau$. Under transformations that stabilize data and model-parameter variances, the most likely Poisson-event occurrence rate, $k/\\tau$, applies for frequentist inference and, also, for Bayesian inference with a Jeffreys prior that ensures posterior invariance under changes of variables. Frequentist confidence intervals and Bayesian (Jeffreys) credibility intervals are approximately the same and easy to calculate: $(1/\\tau)[(\\sqrt{k} - z/2)^{2},(\\sqrt{k} + z/2)^{2}]$, where $z$ is a parameter that specifies the width, $z=1$ ($z=2$) corresponding to $1\\sigma$, $68.3\\%$ ($2\\sigma$, $95.4\\%$). If only a few events have been observed, as is usually the case for extreme events, then these "error-bar" intervals might be considered to be relatively wide. From historical records, we estimate most likely long-term occurrence rates, 10-yr occurrence probabilities, and intervals of frequentist confidence and Bayesian credibility for large earthquakes, explosive volcanic eruptions, and magnetic storms.

  20. Magnetic iron particles with high magnetization useful for immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Tokoro, Hisato [Hitachi Metals, Ltd., Advanced Electronics Research Laboratory, 5200 Mikajiri, Kumagaya, Saitama 360-0843 (Japan)], E-mail: hisato_tokoro@hitachi-metals.co.jp; Nakabayashi, Takashi; Fujii, Shigeo [Hitachi Metals, Ltd., Advanced Electronics Research Laboratory, 5200 Mikajiri, Kumagaya, Saitama 360-0843 (Japan); Zhao Hong; Haefeli, Urs O. [Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC V6T 1Z3 (Canada)

    2009-05-15

    TiO{sub 2}-encapsulated metallic Fe particles (Ti-O/Fe) were synthesized through a solid phase reaction. The Ti-O/Fe particles were non-toxic to tumor cells in a cell viability assay. After silica coating using a sol-gel method, streptavidin was covalently bound onto the Ti-O/Fe particles. Thus produced HMMI particles showed higher magnetization (114 Am{sup 2}/kg) and a larger specific surface area (15 m{sup 2}/g) than conventional streptavidin-immobilized magnetite particles. The high magnetization allowed for rapid magnetic separation, while the additional large specific surface area improved the detection of the adiponectin antigen both in terms of extended detection range and higher assay speed.

  1. High magnetic field magnetization of a new triangular lattice antiferromagnet

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, H. D. [Univ. of Tennessee, Knoxville, TN (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States). National High Magnetic Field Lab. (MagLab); Stritzinger, Laurel Elaine Winter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Harrison, Neil [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-23

    In CsV(MoO4)2, the magnetic V3+ ions with octahedral oxygen-coordination form a geometrically frustrated triangular lattice. So fare, there is no magnetic properties reported on it. Recently, we successfully grew single crystals of CsV(MoO4)2 by using flux method. The susceptibility shows a sharp drop around 24 K, representing a long range magnetic ordering. To understand the physical properties of this new triangular lattice antiferromagnet (TLAF), we pursued high field magnetization measurements to answer two questions: (i) what is the saturation field, which will be very useful to calculate the exchange interaction of the system? (ii) Will it exhibit spin state transition, such as the up up down phase with 1/3-saturation moment as other TLAFs? Recently, we performed VSM measurements in Cell 8, Tallahassee, NHMFL, the results show that the magnetization reaches 0.38 MuB at 34 T, which is just 19% of the full moment of 2 MuB for V3+ (3d2) ions. Apparently we need higher field to reach 1/3 value or full moment.

  2. Rydberg EIT in High Magnetic Field

    Science.gov (United States)

    Ma, Lu; Anderson, David; Miller, Stephanie; Raithel, Georg

    2016-05-01

    We present progress towards an all-optical approach for measurements of strong magnetic fields using electromagnetically induced transparency (EIT) with Rydberg atoms in an atomic vapor. Rydberg EIT spectroscopy is a promising technique for the development of atom-based, calibration- and drift-free technology for high magnetic field sensing. In this effort, Rydberg EIT is employed to spectroscopically investigate the response of Rydberg atoms exposed to strong magnetic fields, in which Rydberg atoms are in the strong-field regime. In our setup, two neodymium block magnets are used to generate fields of about 0.8 Tesla, which strongly perturb the atoms. Information on the field strength and direction is obtained by a comparison of experimental spectra with calculated spectral maps. Investigations of magnetic-field inhomogeneities and other decoherence sources will be discussed.

  3. Magnetic and Superconducting Materials at High Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Struzhkin, Viktor V. [Carnegie Inst. of Washington, Washington, DC (United States)

    2015-03-24

    The work concentrates on few important tasks in enabling techniques for search of superconducting compressed hydrogen compounds and pure hydrogen, investigation of mechanisms of high-Tc superconductivity, and exploring new superconducting materials. Along that route we performed several challenging tasks, including discovery of new forms of polyhydrides of alkali metal Na at very high pressures. These experiments help us to establish the experimental environment that will provide important information on the high-pressure properties of hydrogen-rich compounds. Our recent progress in RIXS measurements opens a whole field of strongly correlated 3d materials. We have developed a systematic approach to measure major electronic parameters, like Hubbard energy U, and charge transfer energy Δ, as function of pressure. This technique will enable also RIXS studies of magnetic excitations in iridates and other 5d materials at the L edge, which attract a lot of interest recently. We have developed new magnetic sensing technique based on optically detected magnetic resonance from NV centers in diamond. The technique can be applied to study superconductivity in high-TC materials, to search for magnetic transitions in strongly correlated and itinerant magnetic materials under pressure. Summary of Project Activities; development of high-pressure experimentation platform for exploration of new potential superconductors, metal polyhydrides (including newly discovered alkali metal polyhydrides), and already known superconductors at the limit of static high-pressure techniques; investigation of special classes of superconducting compounds (high-Tc superconductors, new superconducting materials), that may provide new fundamental knowledge and may prove important for application as high-temperature/high-critical parameter superconductors; investigation of the pressure dependence of superconductivity and magnetic/phase transformations in 3d transition metal compounds, including

  4. An extremely high altitude plume seen at Mars morning terminator

    Science.gov (United States)

    Sanchez-Lavega, Agustin; Garcia-Muñoz, Antonio; Garcia-Melendo, Enrique; Perez-Hoyos, Santiago; Gomez-Forrellad, Josep M.; Pellier, Christophe; Delcroix, Marc; Lopez-Valverde, Miguel Angel; Gonzalez-Galindo, Francisco; Jaeschke, Wayne; Parker, Donald C.; Phillips, James H.; Peach, Damian

    2014-11-01

    We report the occurrence in March and April 2012 of two bright very high altitude plumes at the Martian terminator at 250 km or more above the surface, thus well into the ionosphere and bordering on the exosphere. They were located at about 195 deg West longitude and -45 deg latitude (at Terra Cimmeria) and lasted for about 10 days. The features showed day-to-day variability, and were seen at the morning terminator but not at the evening limb, which indicates rapid evolution in less than 10 hours and a cyclic behavior. Photometric measurements are used to explore two possible scenarios to explain their nature. If the phenomenon is due to suspended particles (dust, CO2 or H2O ice clouds) reflecting solar radiation, the mean size is about 0.1 microns with a nadir optical depth > 0.06. Alternatively, the plume could be auroral emission above a region with a strong magnetic anomaly and where aurora has previously been detected. Importantly, both explanations defy our current understanding of the Mars upper atmosphere.AcknowledgementsThis work was supported by the Spanish MINECO projects AYA2012-36666 with FEDER support, CONSOLIDER program ASTROMOL CSD2009-00038 and AYA2011-30613-CO2-1. Grupos Gobierno Vasco IT765-13 and UPV/EHU UFI11/55.

  5. High-resolution Sonographic Measurements of Lower Extremity Bursae in Chinese Healthy Young Men

    Directory of Open Access Journals (Sweden)

    Yong-Yan Gao

    2016-01-01

    Conclusions: Using HR-US imaging, we were able to analyze lower extremity bursae with high detection rates in healthy young men. The normal ranges of lower extremity bursa dimensions in healthy young men measured by HR-US in this study could be used as reference values for evaluation of bursa abnormalities in the lower extremity.

  6. High resolution simulations of extreme weather event in south Sardinia

    Science.gov (United States)

    Dessy, C.

    2010-05-01

    In the last decade, like most region of Mediterranean Europe, Sardinia has experienced severe precipitation events generating flash floods resulting in loss of lives and large economic damage. A numerical meteorological operational set-up is applied in the local weather service with the aim to improve the operational short range weather forecast of the Service with particular attention to intense, mostly rare and potentially severe, events. On the early hours of 22 October 2008 an intense and almost stationary mesoscale convective system interested particularly the south of Sardinia, heavy precipitation caused a flash flood with fatalities and numerous property damages. The event was particularly intense: about 400 mm of rain in 12 hours (a peak of 150 mm in an hour) were misured by the regional network of weather stations and these values appear extremely meaningfulls since those are about seven times the climatological monthly rainfall for that area and nearly the climatological annual rainfall. With the aim to improve significantly quantitative precipitation forecasting, it was evaluated a different set-up of a high resolution convection resolving model (MM5) initialised with different initial and boundary conditions (ECMWF and NCAR). In this paper it is discussed the meteorological system related to the mentioned event by using different numerical weather models (GCM and LAM) combined with conventional data, radar Doppler and Meteosat images. Preliminary results say that a different set-up of a non hydrostatic model can forecast severe convection events in advance of about one day and produce more realistic rainfall than that current operational and also improve the weather forecasts to respect the ECMWF-GCM. So it could drive an operational alert system in order to limit the risks associated with heavy precipitation events.

  7. Force-Free Magnetic Fields on AN Extreme Reissner-Nordström Spacetime and the Meissner Effect

    Science.gov (United States)

    Takamori, Yousuke; Ken-Ichi, Nakao; Hideki, Ishihara; Masashi, Kimura; Chul-Moon, Yoo

    It is known that the Meissner effect of black holes is seen in the vacuum solutions of blackhole magnetosphere: no non-monopole component of magnetic flux penetrates the event horizon if the black hole is extreme. In this article, in order to see the effects of charge currents, we study the force-free magnetic field on the extreme Reissner-Nordström background. In this case, we should solve one elliptic differential equation called the Grad-Shafranov equation which has singular points called light surfaces. In order to see the Meissner effect, we consider the region near the event horizon and try to solve the equation by Taylor expansion about the event horizon. Moreover, we assume that the small rotational velocity of the magnetic field, and then, we construct a perturbative method to solve the Grad-Shafranov equation considering the efftect of the inner light surface and study the behavior of the magnetic field near the event horizon.

  8. Effects of extremely low frequency magnetic field on anxiety level and spatial memory of adult rats

    Institute of Scientific and Technical Information of China (English)

    HE Li-hua; SHI Hong-mei; LIU Tong-tong; XUYing-chun; YE Kang-ping; WANG Sheng

    2011-01-01

    Background As the widespread use of electric devices in modern life,human are exposed to extremely low frequency magnetic fields (ELF MF) much more frequently than ever.Over the past decades,a substantial number of epidemiological and experimental studies have demonstrated that ELF MF (50 Hz) exposure is associated with increased risk of various health effects.The present study examined the effects of chronic exposure to ELF MF on anxiety level and spatial memory of adult rats.Methods The 50-Hz ELF MF was used during the whole experimental procedures and the value of magnetic field (MF)was set to 2 mT.Adult rats were divided randomly to control,MF 1 hour and MF 4 hours group.Anxiety-related behaviors were examined in the open field test and the elevated plus maze; changes in spatial learning and memory were determined in Morris water maze after 4 weeks of daily exposure.Results Rats in MF 4 hours group had increased anxiety-like behaviors with unaltered locomotor activity.In the Morris water maze test,rats had reduced latency to find the hidden platform and improved long-term memory of former location of platform without changes in short-term memory and locomotor activity.Conclusion Chronic ELF MF exposure has anxiogenic effect on rats,and the promoting effects on spatial learning and long-term retention of spatial memory.

  9. Investigation of exposure to Extremely Low Frequency (ELF) magnetic and electric fields: Ongoing animal studies

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, L.E.

    1994-03-01

    There is now convincing evidence from a large number of laboratories, that exposure to extremely low frequency (ELF) magnetic and electric fields produces biological responses in animals. Many of the observed effects appear to be directly or indirectly associated with the neural or neuroendocrine systems. Such effects include increased neuronal excitability, chemical and hormonal changes in the nervous system, altered behavioral responses, some of which are related to sensing the presence of the field, and changes in endogenous biological rhythms. Additional indices of general physiological status appear relatively unaffected by exposure, although effects have occasionally been described in bone growth and fracture repair, reproduction and development, and immune system function. A major current emphasis in laboratory research is to determine whether or not the reported epidemiological studies that suggest an association between EMF exposure and risk of cancer are supported in studies using animal models. Three major challenges exist for ongoing research: (1) knowledge about the mechanisms underlying observed bioeffects is incomplete, (2) researchers do not as yet understand what physical aspects of exposure produce biological responses, and (3) health consequences resulting from ELF exposure are unknown. Although no animal studies clearly demonstrate deleterious effects of ELF fields, several are suggestive of potential health impacts. From the perspective of laboratory animal studies, this paper will discuss biological responses to ELF magnetic and/or electric field exposures.

  10. Effects of extremely low frequency magnetic field on production of mannatide by α-hemolytic Streptococcus.

    Science.gov (United States)

    Zhang, Jialan; Xu, Cui; Wan, Yunlei; Gao, Mengxiang

    2016-07-01

    The effect of the extremely low frequency magnetic field (ELF-MF) on biomass and mannatide production by α-hemolytic Streptococcus in liquid-state fermentation culture medium was studied during shake flask culture. Magnetic field (MF) inductions, exposure times, and exposure periods varied in a range of 0-1.5 mT, 0-16 h, and six periods of incubation time, respectively. Results showed both biomass and mannatide production increased significantly at MF induction 0.4, 0.6, and 0.9 mT and decreased at both 1.2 and 1.5 mT. Biomass increased by exposure for initial and middle stages of fermentation. Mannatide production increased significantly at 4-8, 8-12, and 17-21 h. Peak yield of biomass and mannatide production increased by 10.7% and 14.0% at 25 and 27 h of incubation at 0.6 mT MF induction and exposure to 8-12 h of incubation time, compared with the control experiment, respectively. ELF-MF could also enhance the growth rate and mannatide production rate of α-hemolytic Streptococcus. However, ELF-MF did not alter α-hemolytic Streptococcus cell growth and mannatide metabolizing regulation or fermentation pattern. Mannatide production was not associated with cellular growth but rather only partially associated. Bioelectromagnetics. 37:331-337, 2016. © 2016 Wiley Periodicals, Inc.

  11. Homogenous BSCCO-2212 Round Wires for Very High Field Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Scott Campbell

    2012-06-30

    The performance demands on modern particle accelerators generate a relentless push towards higher field magnets. In turn, advanced high field magnet development places increased demands on superconducting materials. Nb3Sn conductors have been used to achieve 16 T in a prototype dipole magnet and are thought to have the capability for {approx}18 T for accelerator magnets (primarily dipoles but also higher order multipole magnets). However there have been suggestions and proposals for such magnets higher than 20 T. The High Energy Physics Community (HEP) has identified important new physics opportunities that are enabled by extremely high field magnets: 20 to 50 T solenoids for muon cooling in a muon collider (impact: understanding of neutrinos and dark matter); and 20+ T dipoles and quadrupoles for high energy hadron colliders (impact: discovery reach far beyond present). This proposal addresses the latest SBIR solicitation that calls for grant applications that seek to develop new or improved superconducting wire technologies for magnets that operate at a minimum of 12 Tesla (T) field, with increases up to 15 to 20 T sought in the near future (three to five years). The long-term development of accelerator magnets with fields greater than 20 T will require superconducting wires having significantly better high-field properties than those possessed by current Nb{sub 3}Sn or other A15 based wires. Given the existing materials science base for Bi-2212 wire processing, we believe that Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} (Bi-2212) round wires can be produced in km-long piece lengths with properties suitable to meet both the near term and long term needs of the HEP community. The key advance will be the translation of this materials science base into a robust, high-yield wire technology. While the processing and application of A15 materials have advanced to a much higher level than those of the copper oxide-based, high T{sub c} (HTS) counterparts, the HTS materials have

  12. High Magnetization FeCo/Pd multilayers

    Science.gov (United States)

    Walock, Michael; Klose, Frank; Chshiev, Mairbek; Mankey, Gary; Butler, William

    2007-03-01

    A high saturation magnetization is advantageous in magnetic recording. Currently, the peak of the Slater-Pauling curve is the BCC FeCo system with a saturation magnetization of 2.45 T. Recently, a magnetization of 2.57 T in the FeCo layers of a [40 nm Fe30Co70 /1.7 nm Pd]x25 superlattice has been reported [1, 2]. This behavior may be attributed to an enhanced Fe moment in the expanded FCC matrix, and an accompanying induced moment in the Pd. Our theoretical calculations show an atomic moment enhancement, but this is not great enough to overcome the overall magnetization density reduction caused by the incorporation of Pd in the matrix. The overall effect is a reduced magnetization. Through variation of the FeCo composition and Pd layer thickness, and the combinatorial methods of structural and magnetic characterization, we will gain insight into the magnetic structure of this tertiary thin film system. [1] K. Noma, M. Matsuoka, H. Kanai, Y. Uehara, K. Nomura, and N. Awaji. IEEE Trans. Magn. 42, 140 (2006). [2] ibid. 41, 2920 (2005).

  13. Magnetic Field Gradiometer with Sub-Micron Spatial Resolution Based on Caesium Vapour in an Extremely Thin Cell

    Directory of Open Access Journals (Sweden)

    Auzinsh M.

    2015-06-01

    Full Text Available In this paper we present a device for measuring the magnetic field and its gradient with a spatial resolution of several hundred nanometres. This device is based on caesium metal vapour confined to an extremely thin cell (ETC. To measure magnetic signals, we use absorption and very low laser powers, which might be appealing for modern fabrication techniques. A portable, fully automated device was constructed.

  14. High speed digital phonoscopy of selected extreme vocalization (Conference Presentation)

    Science.gov (United States)

    Izdebski, Krzysztof; Blanco, Matthew; Di Lorenzo, Enrico; Yan, Yuling

    2017-02-01

    We used HSDP (KayPENTAX Model 9710, NJ, USA) to capture the kinematics of vocal folds in the production of extreme vocalization used by heavy metal performers. The vibrations of the VF were captured at 4000 f/s using transoral rigid scope. Growl, scream and inhalatory phonations were recoded. Results showed that these extreme sounds are produced predominantly by supraglottic tissues rather than by the true vocal folds, which explains while these sounds do not injure the mucosa of the true vocal folds. In addition, the HSDI were processed using custom software (Vocalizer®) that clearly demonstrated the contribution of each vocal fold to the generation of the sound.

  15. High Current Planar Magnetics for High Efficiency Bidirectional DC-DC Converters for Fuel Cell Applications

    DEFF Research Database (Denmark)

    Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

    2014-01-01

    Efficiency is one of the main concerns during the design phase of switch mode power supply. Planar magnetics based on PCB windings have the potential to reduce the magnetic manufacturing cost however, one of their main drawbacks comes from their low filling factor and high stray capacitance....... This paper presents an analysis of different planar windings configurations focusing on dc and ac resistances in order to achieve highly efficiency in dc-dc converters. The analysis considers different copper thicknesses form 70 μm up to 1500 μm (extreme copper PCB) taking into account manufacturing...... complexity and challenges. The analysis is focused on a high current inductor for a dc-dc converter for fuel cell applications and it is based on FEM simulations. Analysis and results are verified on a 6 kW dc-dc isolated full bridge boost converter prototype based on fully planar magnetics achieving a peak...

  16. Gap Filling Ceramic Insulating Putty for High Field Magnets

    Science.gov (United States)

    Rice, J. A.; Rice, H. M.

    2008-03-01

    Gaps between the A15 superconducting cable and its supports can sometimes occur requiring expensive rework of the support or filling with a non-optimal material. Recently, a new ceramic putty has been developed that can fill these gaps to fully support the superconducting cable. This ceramic material can withstand the extreme temperature differences between the high temperature heat treatment and the cryogenic operation. Significant performance improvements have been made that will enable the insulating putty to be used in some accelerator magnet systems. Processing methods will be discussed as well as strength and thermal data.

  17. Novel High Temperature Magnetic Bearings for Space Vehicle Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Previous high temperature magnetic bearings employed electromagnets only. The work proposed in this SBIR program seeks to utilize High Temperature Permanent Magnets...

  18. Novel High Temperature Magnetic Bearings for Space Vehicle Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Previous high temperature magnetic bearings employed only electromagnets. The work proposed in this SBIR program seeks to utilize High Temperature Permanent Magnets...

  19. Wuhan pulsed high magnetic field center

    OpenAIRE

    Li, Liang; Peng, Tao; Ding, Honfa; Han, Xiaotao; Ding, Tonghai; Chen, Jin; Wang, Junfeng; Xie, Jianfeng; Wang, Shaoliang; Duan, Xianzhong; Wang, Cheng; Herlach, Fritz; Vanacken, Johan; Pan, Yuan

    2008-01-01

    Wuhan pulsed high magnetic field facility is under development. Magnets of bore sizes from 12 to 34 mm with the peak field in the range of 50 to 80 T have been designed. The pulsed power supplies consists of a 12 MJ, 25 kV capacitor bank and a 100 MVA/100 MJ flywheel pulse generator. A prototype 1 MJ, 25 kV capacitor bank is under construction. Five magnets wound with CuNb wire and copper wire reinforced internally with Zylon fiber composites and externally with stainless steel shells have be...

  20. Tunable high-gradient permanent magnet quadrupoles

    CERN Document Server

    Shepherd, B J A; Marks, N; Collomb, N A; Stokes, D G; Modena, M; Struik, M; Bartalesi, A

    2014-01-01

    A novel type of highly tunable permanent magnet (PM) based quadrupole has been designed by the ZEPTO collaboration. A prototype of the design (ZEPTO-Q1), intended to match the specification for the CLIC Drive Beam Decelerator, was built and magnetically measured at Daresbury Laboratory and CERN. The prototype utilises two pairs of PMs which move in opposite directions along a single vertical axis to produce a quadrupole gradient variable between 15 and 60 T/m. The prototype meets CLIC's challenging specification in terms of the strength and tunability of the magnet.

  1. Wuhan pulsed high magnetic field center

    OpenAIRE

    Li, Liang; Peng, Tao; Ding, Honfa; Han, Xiaotao; Ding, Tonghai; Chen, Jin; Wang, Junfeng; Xie, Jianfeng; Wang, Shaoliang; DUAN, Xianzhong; Wang, Cheng; Herlach, Fritz; Vanacken, Johan; Pan, Yuan

    2008-01-01

    Wuhan pulsed high magnetic field facility is under development. Magnets of bore sizes from 12 to 34 mm with the peak field in the range of 50 to 80 T have been designed. The pulsed power supplies consists of a 12 MJ, 25 kV capacitor bank and a 100 MVA/100 MJ flywheel pulse generator. A prototype 1 MJ, 25 kV capacitor bank is under construction. Five magnets wound with CuNb wire and copper wire reinforced internally with Zylon fiber composites and externally with stainless steel shells have be...

  2. Inelastic X-ray scattering experiments at extreme conditions: high temperatures and high pressures

    Directory of Open Access Journals (Sweden)

    S.Hosokawa

    2008-03-01

    Full Text Available In this article, we review the present status of experimental techniques under extreme conditions of high temperature and high pressure used for inelastic X-ray scattering (IXS experiments of liquid metals, semiconductors, molten salts, molecular liquids, and supercritical water and methanol. For high temperature experiments, some types of single-crystal sapphire cells were designed depending on the temperature of interest and the sample thickness for the X-ray transmission. Single-crystal diamond X-ray windows attached to the externally heated high-pressure vessel were used for the IXS experiment of supercritical water and methanol. Some typical experimental results are also given, and the perspective of IXS technique under extreme conditions is discussed.

  3. Defective iron-oxide nanoparticles synthesised by high temperature plasma processing: a magnetic characterisation versus temperature

    Science.gov (United States)

    Balasubramanian, C.; Joseph, B.; Orpe, PB; Saini, NL; Mukherjee, S.; Dziedzic-Kocurek, K.; Stanek, J.; Di Gioacchino, D.; Marcelli, A.

    2016-11-01

    Magnetic properties and phase compositions of iron-oxide nanoparticles synthesised by a high temperature arc plasma route have been investigated by Mössbauer spectroscopy and high harmonic magnetic AC susceptibility measurements, and correlated with morphological and structural properties for different synthesis conditions. The Mössbauer spectra precisely determined the presence of different iron-oxide fractions in the investigated nanoparticles, while the high harmonic magnetic susceptibility measurements revealed the occurrence of metastable magnetic phases evolving in temperature and time. This study illustrates magnetic properties and dynamics of the magnetic configurations of iron-oxide nanoparticles grown by high temperature plasma, a process less explored so far but extremely useful for synthesising large numbers of nanoparticles for industrial applications.

  4. Occupational extremely low-frequency magnetic field exposure and selected cancer outcomes in a prospective Dutch cohort

    NARCIS (Netherlands)

    Koeman, T.; Brandt, P.A. van den; Slottje, P.; Schouten, L.J.; Goldbohm, R.A.; Kromhout, H.; Vermeulen, R.

    2014-01-01

    Purpose: To investigate the association between exposure to occupational extremely low-frequency magnetic fields (ELF-MF) and the risk of a priori selected cancer outcomes within the prospective Netherlands Cohort Study. Methods: 120,852 men and women aged 55-69 years at time of enrollment in 1986

  5. Occupational exposure to extremely low-frequency magnetic fields and cardiovascular disease mortality in a prospective cohort study

    NARCIS (Netherlands)

    Slottje, Pauline; Kromhout, Hans; Schouten, Leo J.; Goldbohm, R. Alexandra; van den Brandt, Piet A.; Vermeulen, Roel; Koeman, T.

    2013-01-01

    Objectives Although a study among utility workers found an increased risk for acute myocardial infarction and arrhythmia-related deaths associated with occupational extremely low-frequency magnetic fields (ELF-MF) exposure, later studies largely failed to replicate these findings. This study investi

  6. A multicenter reliability study of extremity-magnetic resonance imaging in the longitudinal evaluation of rheumatoid arthritis

    DEFF Research Database (Denmark)

    Conaghan, Philip G; Ejbjerg, Bo; Lassere, Marissa;

    2007-01-01

    There are limited data on the reliability of extremity magnetic resonance imaging (E-MRI) in the longitudinal evaluation of rheumatoid arthritis (RA). Our aim was to assess the interreader reliability of the OMERACT RA MRI score in the assessment of change in disease activity and bone erosion sco...

  7. High-field magnetization in transuranium compound

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, K. [Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan) and KYOKUGEN, Osaka University, Osaka 560-8531 (Japan)]. E-mail: sugiyama@phys.sci.osaka-u.ac.jp; Nakashima, H. [Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Aoki, D. [Institute of Material Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Ikeda, S. [Institute of Material Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Haga, Y. [Advanced Science and Research Centerer, JAEA, Tokai, Ibaraki 319-1195 (Japan); Yamamoto, E. [Advanced Science and Research Centerer, JAEA, Tokai, Ibaraki 319-1195 (Japan); Nakamura, A. [Advanced Science and Research Centerer, JAEA, Tokai, Ibaraki 319-1195 (Japan); Homma, Y. [Institute of Material Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Shiokawa, Y. [Institute of Material Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Kindo, K. [Institite of Solid State Physics, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8581 (Japan); Hagiwara, M. [KYOKUGEN, Osaka University, Osaka 560-8531 (Japan); Onuki, Y. [Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Advanced Science and Research Centerer, JAEA, Tokai, Ibaraki 319-1195 (Japan)

    2007-03-15

    We measured the high-field magnetization up to 55T and constructed a magnetic phase diagram for a transuranium antiferromagnet NpRhGa{sub 5} with the tetragonal structure. The magnetization at 4.2K for H(parallel) [100] indicates a sharp metamagnetic transition with a step at H{sub c}=26T and saturates above H{sub s}=38T, reaching 0.43{mu}{sub B}/Np. An ordered moment of 0.96{mu}{sub B}/Np at zero field, which was determined from the neutron scattering experiment, is found to be reduced to 0.43{mu}{sub B}/Np at H{sub s}, together with an orientation of the magnetic moment from the (001) plane to the (100) plane.

  8. Supine spinal magnetic resonance imaging with straightened lower extremities in spondylolisthesis: A comparison with the conventional technique

    Energy Technology Data Exchange (ETDEWEB)

    Daghighi, Mohammad Hossein; Poureisa, Masoud; Arablou, Farid [Department of Radiology, Imam Reza Teaching Center, Tabriz University of Medical Sciences, Tabriz (Iran, Islamic Republic of); Fouladi, Daniel F., E-mail: medicorelax@yahoo.com [Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz (Iran, Islamic Republic of)

    2015-05-15

    Highlights: • MR imaging with straightened lower extremities was tested in spondylolisthesis. • This technique is more accurate than conventional MR imaging in detecting slip. • Level of spondylolisthesis is the only independent predictor of severity of slip. - Abstract: Objectives: To compare the degree of slip in spondylolisthesis on supine magnetic resonance (MR) images obtained with flexed and straightened lower extremities. Methods: Supine spinal MR studies were performed in 100 cases of symptomatic spondylolisthesis with flexed and then straightened lower extremities. The angle of lumbar lordosis (by Cobb's method) and the degree of slip (by Taillard's method) were compared between the two sets of images. Results: The mean angle of lumbar lordosis increased from 51.65 ± 8.57° on MR images with flexed lower limbs to 57.39 ± 9.05° on MR images with straightened lower limbs (p < 0.001; mean percent increase: 11.51%). Similar change was also observed for the mean degree of slip (from 25.80 ± 7.74% to 28.68 ± 7.93%, p < 0.001; mean percent increase: 12.60%). After MR imaging with straightened lower extremities 22 out of 54 initially grade I cases had grade II disease (p < 0.001). Conclusions: Supine magnetic resonance imaging with straightened lower extremities detects higher degree of slippage in symptomatic patients with spondylolisthesis compared to conventional MRI with flexed lower extremities.

  9. Extremely High Resolution Spectroscopy of Oxide Electronic Systems

    Science.gov (United States)

    2013-01-29

    interfaces. Using torque magnetometry, we have discovered a strong paramagnetism (or soft ferromagnetism ) that coexists with the superconducting ...magnetism is quite large, around 0.3 Bohr magnetons per unit cell. If the ferromagnetism and superconductive both occur at the interface (as our...range RKKY coupling between spins in the interfacial layer that produces ferromagnetism in the interfacial layer. MPL describe the superconductivity

  10. Extreme Particle Acceleration in Magnetic Reconnection Layers: Application to the Gamma-Ray Flares in the Crab Nebula

    Science.gov (United States)

    Cerutti, Benoît; Uzdensky, Dmitri A.; Begelman, Mitchell C.

    2012-02-01

    The gamma-ray space telescopes AGILE and Fermi detected short and bright synchrotron gamma-ray flares at photon energies above 100 MeV in the Crab Nebula. This discovery suggests that electron-positron pairs in the nebula are accelerated to PeV energies in a milligauss magnetic field, which is difficult to explain with classical models of particle acceleration and pulsar wind nebulae. We investigate whether particle acceleration in a magnetic reconnection layer can account for the puzzling properties of the flares. We numerically integrate relativistic test-particle orbits in the vicinity of the layer, including the radiation reaction force, and using analytical expressions for the large-scale electromagnetic fields. As they get accelerated by the reconnection electric field, the particles are focused deep inside the current layer where the magnetic field is small. The electrons suffer less from synchrotron losses and are accelerated to extremely high energies. Population studies show that, at the end of the layer, the particle distribution piles up at the maximum energy given by the electric potential drop and is focused into a thin fan beam. Applying this model to the Crab Nebula, we find that the emerging synchrotron emission spectrum peaks above 100 MeV and is close to the spectral shape of a single electron. The flare inverse Compton emission is negligible and no detectable emission is expected at other wavelengths. This mechanism provides a plausible explanation for the gamma-ray flares in the Crab Nebula and could be at work in other astrophysical objects such as relativistic jets in active galactic nuclei.

  11. Characterization of Extremely Low Frequency Magnetic Fields from Diesel, Gasoline and Hybrid Cars under Controlled Conditions

    Directory of Open Access Journals (Sweden)

    Ronen Hareuveny

    2015-01-01

    Full Text Available This study characterizes extremely low frequency (ELF magnetic field (MF levels in 10 car models. Extensive measurements were conducted in three diesel, four gasoline, and three hybrid cars, under similar controlled conditions and negligible background fields. Averaged over all four seats under various driving scenarios the fields were lowest in diesel cars (0.02 μT, higher for gasoline (0.04–0.05 μT and highest in hybrids (0.06–0.09 μT, but all were in-line with daily exposures from other sources. Hybrid cars had the highest mean and 95th percentile MF levels, and an especially large percentage of measurements above 0.2 μT. These parameters were also higher for moving conditions compared to standing while idling or revving at 2500 RPM and higher still at 80 km/h compared to 40 km/h. Fields in non-hybrid cars were higher at the front seats, while in hybrid cars they were higher at the back seats, particularly the back right seat where 16%–69% of measurements were greater than 0.2 μT. As our results do not include low frequency fields (below 30 Hz that might be generated by tire rotation, we suggest that net currents flowing through the cars’ metallic chassis may be a possible source of MF. Larger surveys in standardized and well-described settings should be conducted with different types of vehicles and with spectral analysis of fields including lower frequencies due to magnetization of tires.

  12. Weak Static and Extremely Low Frequency Magnetic Fields Affect In Vitro Pollen Germination

    Directory of Open Access Journals (Sweden)

    Lucietta Betti

    2011-01-01

    Full Text Available This study concerns the effects of a weak static magnetic field (MF at 10 μT oriented downward, combined with a 16-Hz sinusoidal MF (10 μT, on in vitro pollen germination of kiwifruit (Actinidia deliciosa. Extremely low frequency magnetic field (ELF-MF exposure was carried out by a signal generator unit connected to a copper wire solenoid, inside which samples where placed. Two different kinds of treatment were performed: direct and indirect. In the direct treatment, pollen samples were directly exposed during rehydration, germination, or both. In the indirect treatment, the pollen growth medium was prepared with water aliquots (at standard temperature of 20°C and pH = 6.74 that were exposed before use for 8 or 24 h. The main purpose of our research was to identify a biological marker (in vitro pollen germination in a stressing growth medium without Ca2+ susceptible to the effects of direct or indirect ELF-MF exposure. The working variable was the pollen germination rate, as detected blind after 3 h 30 min by an Axioplan microscope. A directionally consistent recovery of germination percentage was observed both for direct exposure (during germination and both rehydration and germination phases and water-mediated exposure (with water exposed for 24 h and immediately used. Our results suggest that the ELF-MF treatment might partially remove the inhibitory effect caused by the lack of Ca2+ in the culture medium, inducing a release of internal Ca2+ stored in the secretory vesicles of pollen plasma membrane. Although preliminary, findings seem to indicate the in vitro pollen performance as adequate to study the effects of ELF-MFs on living matter.

  13. Reliability of High I/O High Density CCGA Interconnect Electronic Packages under Extreme Thermal Environment

    Science.gov (United States)

    Ramesham, Rajeshuni

    2012-01-01

    This paper provides the experimental test results of advanced CCGA packages tested in extreme temperature thermal environments. Standard optical inspection and x-ray non-destructive inspection tools were used to assess the reliability of high density CCGA packages for deep space extreme temperature missions. Ceramic column grid array (CCGA) packages have been increasing in use based on their advantages such as high interconnect density, very good thermal and electrical performances, compatibility with standard surface-mount packaging assembly processes, and so on. CCGA packages are used in space applications such as in logic and microprocessor functions, telecommunications, payload electronics, and flight avionics. As these packages tend to have less solder joint strain relief than leaded packages or more strain relief over lead-less chip carrier packages, the reliability of CCGA packages is very important for short-term and long-term deep space missions. We have employed high density CCGA 1152 and 1272 daisy chained electronic packages in this preliminary reliability study. Each package is divided into several daisy-chained sections. The physical dimensions of CCGA1152 package is 35 mm x 35 mm with a 34 x 34 array of columns with a 1 mm pitch. The dimension of the CCGA1272 package is 37.5 mm x 37.5 mm with a 36 x 36 array with a 1 mm pitch. The columns are made up of 80% Pb/20%Sn material. CCGA interconnect electronic package printed wiring polyimide boards have been assembled and inspected using non-destructive x-ray imaging techniques. The assembled CCGA boards were subjected to extreme temperature thermal atmospheric cycling to assess their reliability for future deep space missions. The resistance of daisy-chained interconnect sections were monitored continuously during thermal cycling. This paper provides the experimental test results of advanced CCGA packages tested in extreme temperature thermal environments. Standard optical inspection and x-ray non

  14. Reliability of High I/O High Density CCGA Interconnect Electronic Packages under Extreme Thermal Environment

    Science.gov (United States)

    Ramesham, Rajeshuni

    2012-01-01

    This paper provides the experimental test results of advanced CCGA packages tested in extreme temperature thermal environments. Standard optical inspection and x-ray non-destructive inspection tools were used to assess the reliability of high density CCGA packages for deep space extreme temperature missions. Ceramic column grid array (CCGA) packages have been increasing in use based on their advantages such as high interconnect density, very good thermal and electrical performances, compatibility with standard surface-mount packaging assembly processes, and so on. CCGA packages are used in space applications such as in logic and microprocessor functions, telecommunications, payload electronics, and flight avionics. As these packages tend to have less solder joint strain relief than leaded packages or more strain relief over lead-less chip carrier packages, the reliability of CCGA packages is very important for short-term and long-term deep space missions. We have employed high density CCGA 1152 and 1272 daisy chained electronic packages in this preliminary reliability study. Each package is divided into several daisy-chained sections. The physical dimensions of CCGA1152 package is 35 mm x 35 mm with a 34 x 34 array of columns with a 1 mm pitch. The dimension of the CCGA1272 package is 37.5 mm x 37.5 mm with a 36 x 36 array with a 1 mm pitch. The columns are made up of 80% Pb/20%Sn material. CCGA interconnect electronic package printed wiring polyimide boards have been assembled and inspected using non-destructive x-ray imaging techniques. The assembled CCGA boards were subjected to extreme temperature thermal atmospheric cycling to assess their reliability for future deep space missions. The resistance of daisy-chained interconnect sections were monitored continuously during thermal cycling. This paper provides the experimental test results of advanced CCGA packages tested in extreme temperature thermal environments. Standard optical inspection and x-ray non

  15. High-Field Magnetization of Some Mn Alloys(Magnetism)

    OpenAIRE

    Tomiei, Hori; Hiroshi, Shiraishi; Hiroshi, Niida; Hiroaki, Kato; Giyuu, Kido; Yasuo, Yamaguchi; Yasuaki, Nakagawa; Shibaura Institute of Technology; Institute for Materials Research, Tohoku University

    1993-01-01

    We have made high-field magnetization measurements for some Mn alloys : ε-Mn_Ga with δ= -0.30, ε-(Mn_Fe_x)_3Sn with x=0.1 and 0.3, Fe_3Mn_4Ge_ and γ-(Mn_Fe_x)_Ga_y with x=0.44 and y=0.27. The ε-Mn_Ga has the hexagonal D0_ type structure and a distorted triangular antiferromagnetic spin structure. The hexagonal lattice is slightly distorted to an orthorhombic lattice at T_d of about 290 K with large magnetization. Pseudo-binary ε-(Mn_Fe_x)_3Sn has also the D0_ type structure, and the alloys wi...

  16. Study of flow fractionation characteristics of magnetic chromatography utilizing high-temperature superconducting bulk magnet

    Directory of Open Access Journals (Sweden)

    Satoshi Fukui, Yoshihiro Shoji, Jun Ogawa, Tetsuo Oka, Mitsugi Yamaguchi, Takao Sato, Manabu Ooizumi, Hiroshi Imaizumi and Takeshi Ohara

    2009-01-01

    Full Text Available We present numerical simulation of separating magnetic particles with different magnetic susceptibilities by magnetic chromatography using a high-temperature superconducting bulk magnet. The transient transport is numerically simulated for two kinds of particles having different magnetic susceptibilities. The time evolutions were calculated for the particle concentration in the narrow channel of the spiral arrangement placed in the magnetic field. The field is produced by the highly magnetized high-temperature superconducting bulk magnet. The numerical results show the flow velocity difference of the particle transport corresponding to the difference in the magnetic susceptibility, as well as the possible separation of paramagnetic particles of 20 nm diameter.

  17. Further Evidence on the "Costs of Privilege": Perfectionism in High-Achieving Youth at Socioeconomic Extremes

    Science.gov (United States)

    Lyman, Emily L.; Luthar, Suniya S.

    2014-01-01

    This study involved two academically-gifted samples of 11th and 12th grade youth at the socioeconomic status (SES) extremes; one from an exclusive private, affluent school, and the other from a magnet school with low-income students. Negative and positive adjustment outcomes were examined in relation to multiple dimensions of perfectionism…

  18. Two Rare Magnetic Cataclysmic Variables with Extreme Cyclotron Features Identified in the Sloan Digital Sky Survey

    CERN Document Server

    Szkody, P; Schmidt, G; Hall, P B; Margon, B; Miceli, A; Subba-Rao, M; Frith, W J; Harris, H; Szkody, Paula; Anderson, Scott F.; Schmidt, Gary; Hall, Patrick B.; Margon, Bruce; Miceli, Antonino; Rao, Mark Subba; Frith, James; Harris, Hugh

    2003-01-01

    Two newly identified magnetic cataclysmic variables discovered in the Sloan Digital Sky Survey (SDSS), SDSSJ155331.12+551614.5 and SDSSJ132411.57+032050.5, have spectra showing highly prominent, narrow, strongly polarized cyclotron humps with amplitudes that vary on orbital periods of 4.39 and 2.6 hrs, respectively. In the former, the spacing of the humps indicates the 3rd and 4th harmonics in a magnetic field of ~60 MG. The narrowness of the cyclotron features and the lack of strong emission lines imply very low temperature plasmas and very low accretion rates, so that the accreting area is heated by particle collisions rather than accretion shocks. The detection of rare systems like these exemplifies the ability of the SDSS to find the lowest accretion rate close binaries.

  19. Performance Verification of the Gravity and Extreme Magnetism Small Explorer GEMS X-Ray Polarimeter

    Science.gov (United States)

    Enoto, Teruaki; Black, J. Kevin; Kitaguchi, Takao; Hayato, Asami; Hill, Joanne E.; Jahoda, Keith; Tamagawa, Toru; Kanako, Kenta; Takeuchi, Yoko; Yoshikawa, Akifumi; Kenward, David

    2014-01-01

    olarimetry is a powerful tool for astrophysical observations that has yet to be exploited in the X-ray band. For satellite-borne and sounding rocket experiments, we have developed a photoelectric gas polarimeter to measure X-ray polarization in the 2-10 keV range utilizing a time projection chamber (TPC) and advanced micro-pattern gas electron multiplier (GEM) techniques. We carried out performance verification of a flight equivalent unit (1/4 model) which was planned to be launched on the NASA Gravity and Extreme Magnetism Small Explorer (GEMS) satellite. The test was performed at Brookhaven National Laboratory, National Synchrotron Light Source (NSLS) facility in April 2013. The polarimeter was irradiated with linearly-polarized monochromatic X-rays between 2.3 and 10.0 keV and scanned with a collimated beam at 5 different detector positions. After a systematic investigation of the detector response, a modulation factor greater than or equal to 35% above 4 keV was obtained with the expected polarization angle. At energies below 4 keV where the photoelectron track becomes short, diffusion in the region between the GEM and readout strips leaves an asymmetric photoelectron image. A correction method retrieves an expected modulation angle, and the expected modulation factor, approximately 20% at 2.7 keV. Folding the measured values of modulation through an instrument model gives sensitivity, parameterized by minimum detectable polarization (MDP), nearly identical to that assumed at the preliminary design review (PDR).

  20. Extremely low-frequency magnetic field exposure, electrical shocks and risk of Parkinson's disease.

    Science.gov (United States)

    van der Mark, Marianne; Vermeulen, Roel; Nijssen, Peter C G; Mulleners, Wim M; Sas, Antonetta M G; van Laar, Teus; Kromhout, Hans; Huss, Anke

    2015-02-01

    Previous studies did not provide strong evidence for an increased Parkinson's disease (PD) risk after exposure to extremely low-frequency magnetic fields (ELF-MF), but were limited in their scope to address other exposures related to the use of electricity such as electrical shocks. We evaluated the associations of PD with exposure to ELF-MF, electrical shocks and having worked in "electrical occupations." We conducted a hospital-based case-control study, including 444 PD patients and 876 age- and sex-matched controls. Occupational histories were collected in telephone interviews and were linked to job-exposure matrices on ELF-MF exposure and on electrical shocks. In addition, questions on use of household appliances involving ELF-MF exposure, experienced electrical shocks and potential confounders were asked. No association of PD risk with any of the evaluated exposures related to electricity was observed. We did, however, observe quite consistently reduced risk estimates across the majority of the exposure categories explored. Given the results of the previous studies and the absence of any postulated mechanism, this is unlikely to represent a true protective effect of ELF-MF or electrical shocks on the occurrence of PD. The results of this study suggest that no association exists between PD and exposure to ELF-MF, electrical shocks or having worked in "electrical occupations."

  1. Extremely low frequency magnetic fields induce oxidative stress in rat brain.

    Science.gov (United States)

    Manikonda, Pavan K; Rajendra, Pilankatta; Devendranath, D; Gunasekaran, B; Channakeshava; Aradhya, Shivakumara R S; Sashidhar, Rao B; Subramanyam, Chivukula

    2014-01-01

    The present investigation was conducted to understand the influence of long-term exposure of rats to extremely low frequency magnetic fields (ELF-MF), focusing on oxidative stress (OS) on different regions of rat's brain. Male Wistar rats (21-day-old) were exposed to ELF-MF (50 Hz; 50 and 100 µT) for 90 days continuously; hippocampal, cerebellar and cortical regions from rats were analyzed for (i) reactive oxygen species (ROS), (ii) metabolites indicative of OS and (iii) antioxidant enzymes. In comparison to control group rats, the rats that were continuously exposed to ELF-MF caused OS and altered glutathione (GSH/GSSG) levels in dose-dependent manner in all the regions of the brain. Accumulation of ROS, lipid peroxidation end products and activity of superoxide dismutase in different regions was in the descending order of cerebellum glutathione peroxidase activity were in the descending order of hippocampus 50 µT. Varied influences observed in different regions of the brain, as documented in this study, may contribute to altered metabolic patterns in its related regions of the central nervous system, leading to aberrant neuronal functions.

  2. High temperature superconductors for magnetic suspension applications

    Science.gov (United States)

    Mcmichael, C. K.; Cooley, R. S.; Chen, Q. Y.; Ma, K. B.; Lamb, M. A.; Meng, R. L.; Chu, C. W.; Chu, W. K.

    1994-01-01

    High temperature superconductors (HTS) hold the promise for applications in magnetic levitation bearings, vibration damping, and torque coupling. Traditional magnetic suspension systems require active feedback and vibration controls in which power consumption and low frequency vibration are among the major engineering concerns. HTS materials have been demonstrated to be an enabling approach towards such problems due to their flux trapping properties. In our laboratory at TCSUH, we have been conducting a series of experiments to explore various mechanical applications using HTS. We have constructed a 30 lb. model flywheel levitated by a hybrid superconducting magnetic bearing (HSMB). We are also developing a levitated and vibration-dampled platform for high precision instrumentation. These applications would be ideal for space usages where ambient temperature is adequate for HTS to operate properly under greatly reduced cryogenic requirements. We will give a general overview of these potential applications and discuss the operating principles of the HTS devices we have developed.

  3. Magnetic fields during high redshift structure formation

    CERN Document Server

    Schleicher, Dominik R G; Schober, Jennifer; Schmidt, Wolfram; Bovino, Stefano; Federrath, Christoph; Niemeyer, Jens; Banerjee, Robi; Klessen, Ralf S

    2012-01-01

    We explore the amplification of magnetic fields in the high-redshift Universe. For this purpose, we perform high-resolution cosmological simulations following the formation of primordial halos with \\sim10^7 M_solar, revealing the presence of turbulent structures and complex morphologies at resolutions of at least 32 cells per Jeans length. Employing a turbulence subgrid-scale model, we quantify the amount of unresolved turbulence and show that the resulting turbulent viscosity has a significant impact on the gas morphology, suppressing the formation of low-mass clumps. We further demonstrate that such turbulence implies the efficient amplification of magnetic fields via the small-scale dynamo. We discuss the properties of the dynamo in the kinematic and non-linear regime, and explore the resulting magnetic field amplification during primordial star formation. We show that field strengths of \\sim10^{-5} G can be expected at number densities of \\sim5 cm^{-3}.

  4. Physics of semiconductors in high magnetic fields

    CERN Document Server

    Miura, Noboru

    2008-01-01

    This book summarizes most of the fundamental physical phenomena which semiconductors and their modulated structures exhibit in high magnetic fields. Readers can learn not only the basic theoretical background but also the present state of the art from the most advanced data in this rapidly growing research area.

  5. In situ observation of magnetic orientation process of feeble magnetic materials under high magnetic fields

    Directory of Open Access Journals (Sweden)

    Noriyuki Hirota et al

    2008-01-01

    Full Text Available An in situ microscopic observation of the magnetic orientation process of feeble magnetic fibers was carried out under high magnetic fields of up to 10 T using a scanning laser microscope. In the experiment, carbon fibers and needle-like titania fibers with a length of 1 to 20 μm were used. The fibers were observed to gradually orient their axes parallel to the direction of the magnetic field. The orientation behavior of the sample fibers was evaluated on the basis of the measured duration required for a certain angular variation. As predicted from the theoretical consideration, it was confirmed that the duration required for a certain angular variation normalized by the viscosity of the fluid is described as a function of the fiber length. The results obtained here appear useful for the consideration of the magnetic orientation of materials suspended in a static fluid.

  6. A Compact High Gradient Pulsed Magnetic Quadrupole

    CERN Document Server

    Shuman, Derek; Kireeff Covo, Michel; Ritchie, Gary; Seidl, Peter

    2005-01-01

    A design for a high gradient, low inductance pulsed quadrupole magnet is presented. The magnet is a circular current dominated design with a circular iron return yoke. Features include a five turn eddy current compensated solid conductor coil design which theoretically eliminates the first four higher order multipole field components, a single layer "non-spiral bedstead" coil design which both minimizes utilization of radial space and maximizes utilization of axial space, and allows incorporation of steering and correction coils within existing radial space. The coils are wound and stretched straight in a special winder, then bent in simple fixtures to form the upturned ends, simplifying fabrication and assembly.

  7. Biological systems in high magnetic field

    Science.gov (United States)

    Yamagishi, A.

    1990-12-01

    Diamagnetic orientation of biological systems have been investigated theoretically and experimentally. Fibrinogen, one of blood proteins, were polymerized in static high magnetic fields up to 8 T. Clotted gels composed of oriented fibrin fibers were obtained even in a field as low as 1 T. Red blood cells (RBC) show full orientation with their plane parallel to the applied field of 4 T. It is confirmed experimentally that the magnetic orientation of RBC is caused by diamagnetic anisotropy. Full orientation is also obtained with blood platelet in a field of 3 T.

  8. High-field Magnet Development toward the High Luminosity LHC

    Energy Technology Data Exchange (ETDEWEB)

    Apollinari, Giorgio [Fermilab

    2014-07-01

    The upcoming Luminosity upgrade of the LHC (HL-LHC) will rely on the use of Accelerator Quality Nb3Sn Magnets which have been the focus of an intense R&D effort in the last decade. This contribution will describe the R&D and results of Nb3Sn Accelerator Quality High Field Magnets development efforts, with emphasis on the activities considered for the HL-LHC upgrades.

  9. Creep strength of iridium at extremely high temperatures; Zeitstandfestigkeit von Iridium bei extrem hohen Temperaturen

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, B. [Fachhochschule Jena (Germany). Fachbereich Werkstofftechnik; Lupton, D. [Heraeus (W.C.) GmbH, Hanau (Germany). Produktbereich Materialtechnik; Braun, F. [Heraeus (W.C.) GmbH, Hanau (Germany). Produktbereich Materialtechnik; Merker, J. [Jena Univ. (Germany). Technisches Inst.; Helmich, R. [Jena Univ. (Germany). Technisches Inst.

    1994-12-31

    On iridium in the initial state and after carrying out creep tests, apart from metallographic and fractographic work, investigations on the distribution of trace impurities were done by means of secondary ion mass spectroscopy and investigations of the crystal structure were carried out with the aid of Kossel technique, a special field of X-ray bending. Although iridium of high purity was used for the investigations, enrichment of hydrogen, carbon, sodium, potassium, calcium, magnesium, silicon, iron, nickel and chromium was proved by means of secondary ion mass spectroscopy at the grain boundaries, where the average contents in iridium were only about 1 {mu}g/g. In the creep test, creep fracture lines were found in the range of 1800 to 2300 C and about 0.5 to 12 hours on iridium samples with a square cross section of 1 mm. It follows from the results that this noble metal has a considerable resistance to heat at these temperatures, which makes its use up to 2300 C possible. (orig./RHM) [Deutsch] Es erfolgten am Iridium im Ausgangszustand und nach Durchfuehrung der Zeitstandversuche neben metallographischen und fraktographischen Arbeiten Untersuchungen zur Verteilung der Spurenverunreinigungen mittels Sekundaerionen-Massenspektroskopie sowie Untersuchungen der Kristallstruktur mit Hilfe der Kossel-Technik, einem Spezialgebiet der Roentgenbeugung. Obwohl fuer die Untersuchungen hochreines Iridium verwendet wurde, konnten mittels Sekundaerionen-Massenspektroskopie in den Korngrenzen Anreicherungen von Wasserstoff, Kohlenstoff, Natrium, Kalium, Calcium, Magnesium, Silizium, Eisen, Nickel und Chrom nachgewiesen werden, wobei die durchschnittlichen Gehalte in Iridium nur um 1 {mu}g/g lagen. Im Zeitstandversuch wurden an Iridiumproben mit 1 mm Vierkantquerschnitt Zeitbruchlinien im Bereich von 1800 bis 2300 C und etwa 0,5 bis 12 Stunden aufgenommen. Aus den Ergebnissen folgt, dass das Edelmetall bei diesen Temperaturen noch eine beachtliche Warmfestigkeit besitzt, die

  10. Permanent magnets composed of high temperature superconductors

    Science.gov (United States)

    Weinstein, Roy; Chen, In-Gann; Liu, Jay; Lau, Kwong

    1991-01-01

    A study of persistent, trapped magnetic field has been pursued with high-temperature superconducting (HTS) materials. The main effort is to study the feasibility of utilization of HTS to fabricate magnets for various devices. The trapped field, when not in saturation, is proportional to the applied field. Thus, it should be possible to replicate complicated field configurations with melt-textured YBa2Cu3O7 (MT-Y123) material, bypassing the need for HTS wires. Presently, materials have been developed from which magnets of 1.5 T, at 77 K, can be fabricated. Much higher field is available at lower operating temperature. Stability of a few percent per year is readily attainable. Results of studies on prototype motors and minimagnets are reported.

  11. High magnetic fields in the USA

    Science.gov (United States)

    Campbell, Laurence J.; Parkin, Don E.; Crow, Jack E.; Schneider-Muntau, Hans J.; Sullivan, Neil S.

    During the past thirty years research using high magnetic fields has technically evolved in the manner, but not the magnitude, of the so-called big science areas of particle physics, plasma physics, neutron scattering, synchrotron light scattering, and astronomy. Starting from the laboratories of individual researchers it moved to a few larger universities, then to centralized national facilities with research and maintenance staffs, and, finally, to joint international ventures to build unique facilities, as illustrated by the subject of this conference. To better understand the nature of this type of research and its societal justification it is helpful to compare it, in general terms, with the aforementioned big-science fields. High magnetic field research differs from particle physics, plasma physics, and astronomy in three respects: (1) it is generic research that cuts across a wide range of scientific disciplines in physics, chemistry, biology, medicine, and engineering; (2) it studies materials and processes that are relevant for a variety of technological applications and it gives insight into biological processes; (3) it has produced, at least, comparably significant results with incomparably smaller resources. Unlike neutron and synchrotron light scattering, which probe matter, high magnetic fields change the thermodynamic state of matter. This change of state is fundamental and independent of other state variables, such as pressure and temperature. After the magnetic field is applied, various techniques are then used to study the new state.

  12. Two-dimensional resonant magnetic soft X-ray scattering set-up for extreme sample environment.

    Science.gov (United States)

    Stanescu, Stefan; Mocuta, Cristian; Merlet, Frederic; Barbier, Antoine

    2013-01-01

    The newly built MagSAXS (magnetic small-angle X-ray scattering) set-up dedicated to the direct two-dimensional measurement of magnetic scattering using polarized synchrotron radiation in extreme sample environments is presented. Pure optical transport of the image is used to record the magnetic scattering with a two-dimensional CCD visible-light camera. The set-up is able to probe magnetic correlation lengths from the micrometer down to the nanometer scale. A detailed layout is presented along with preliminary results obtained at several beamlines at Synchrotron SOLEIL. The presented examples underline the wide range of possible applications spanning from correlation lengths determination to Fourier transform holography.

  13. Improving Magnet Designs With High and Low Field Regions

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Bahl, Christian Robert Haffenden; Smith, Anders

    2011-01-01

    to low field regions. Also, a general way to replace magnet material with a high permeability soft magnetic material where appropriate is discussed. As an example, these schemes are applied to a two dimensional concentric Halbach cylinder design resulting in a reduction of the amount of magnet material......A general scheme for increasing the difference in magnetic flux density between a high and a low magnetic field region by removing unnecessary magnet material is presented. This is important in, e.g., magnetic refrigeration where magnet arrays have to deliver high field regions in close proximity...

  14. Pocket atlas of sectional anatomy: computed tomography and magnetic resonance imaging. Vol. 3. Spine, extremities, joints

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, T.B.; Reif, E. [Caritas Hospital, Dillingen (Germany). Dept. of Radiology

    2007-07-01

    Magnetic resonance imaging (MRI) of the musculoskeletal system is an established and important component in the diagnosis of diseases of the joints, soft tissues, bones, and bone marrow. We are therefore pleased to collect together images of the joints and the spinal column in a separate volume on the musculoskeletal system. Demonstrating the growing importance of new developments in MRI in recent years, with ever-increasing resolution, many images were acquired with 3-tesla units. We are deeply grateful to the manufacturers, Siemens and Philips, for making this possible. We believe that colored atlases are the ideal medium to represent the highly detailed images achieved nowadays with improved resolution techniques. Volume 3 of the Pocket Atlas of Sectional Anatomay provides a color illustration facing each magnetic resonance image, as in the preceding volumes on the skull, thorax, and abdomen. To ensure the greatest possible precision in details, we still produce these illustrations ourselves. Each is accompanied by a sectional image and an orientation aid. Uniform color schemes ensure optimal clarity, as similar structures, such as arteries, veins, nerves, tendons, etc., are consistently represented in the same color. Individual muscle groups are represented uniformly, but differentiated from other muscle groups, so that classification is possible even when numerous groups of muscles are shown in the same image. Maximal lucidity prevails even in highly detailed representations. This is made possible by the high quality of the production and printing process that are characteristic of Thieme International. (orig.)

  15. Extremely short duration high intensity interval training substantially improves insulin action in young healthy males

    DEFF Research Database (Denmark)

    Babraj, John A; Vollaard, Niels B J; Keast, Cameron

    2009-01-01

    BACKGROUND: Traditional high volume aerobic exercise training reduces cardiovascular and metabolic disease risk but involves a substantial time commitment. Extremely low volume high-intensity interval training (HIT) has recently been demonstrated to produce improvements to aerobic function, but i...

  16. Fail Safe, High Temperature Magnetic Bearings

    Science.gov (United States)

    Minihan, Thomas; Palazzolo, Alan; Kim, Yeonkyu; Lei, Shu-Liang; Kenny, Andrew; Na, Uhn Joo; Tucker, Randy; Preuss, Jason; Hunt, Andrew; Carter, Bart; hide

    2002-01-01

    This paper contributes to the magnetic bearing literature in two distinct areas: high temperature and redundant actuation. Design considerations and test results are given for the first published combined 538 C (1000 F) high speed rotating test performance of a magnetic bearing. Secondly, a significant extension of the flux isolation based, redundant actuator control algorithm is proposed to eliminate the prior deficiency of changing position stiffness after failure. The benefit of the novel extension was not experimentally demonstrated due to a high active stiffness requirement. In addition, test results are given for actuator failure tests at 399 C (750 F), 12,500 rpm. Finally, simulation results are presented confirming the experimental data and validating the redundant control algorithm.

  17. Inhibition of angiogenesis mediated by extremely low-frequency magnetic fields (ELF-MFs.

    Directory of Open Access Journals (Sweden)

    Simona Delle Monache

    Full Text Available The formation of new blood vessels is an essential therapeutic target in many diseases such as cancer, ischemic diseases, and chronic inflammation. In this regard, extremely low-frequency (ELF electromagnetic fields (EMFs seem able to inhibit vessel growth when used in a specific window of amplitude. To investigate the mechanism of anti-angiogenic action of ELF-EMFs we tested the effect of a sinusoidal magnetic field (MF of 2 mT intensity and frequency of 50 Hz on endothelial cell models HUVEC and MS-1 measuring cell status and proliferation, motility and tubule formation ability. MS-1 cells when injected in mice determined a rapid tumor-like growth that was significantly reduced in mice inoculated with MF-exposed cells. In particular, histological analysis of tumors derived from mice inoculated with MF-exposed MS-1 cells indicated a reduction of hemangioma size, of blood-filled spaces, and in hemorrhage. In parallel, in vitro proliferation of MS-1 treated with MF was significantly inhibited. We also found that the MF-exposure down-regulated the process of proliferation, migration and formation of tubule-like structures in HUVECs. Using western blotting and immunofluorescence analysis, we collected data about the possible influence of MF on the signalling pathway activated by the vascular endothelial growth factor (VEGF. In particular, MF exposure significantly reduced the expression and activation levels of VEGFR2, suggesting a direct or indirect influence of MF on VEGF receptors placed on cellular membrane. In conclusion MF reduced, in vitro and in vivo, the ability of endothelial cells to form new vessels, most probably affecting VEGF signal transduction pathway that was less responsive to activation. These findings could not only explain the mechanism of anti-angiogenic action exerted by MFs, but also promote the possible development of new therapeutic applications for treatment of those diseases where excessive angiogenesis is involved.

  18. Inhibition of Angiogenesis Mediated by Extremely Low-Frequency Magnetic Fields (ELF-MFs)

    Science.gov (United States)

    Delle Monache, Simona; Angelucci, Adriano; Sanità, Patrizia; Iorio, Roberto; Bennato, Francesca; Mancini, Fabrizio; Gualtieri, Giancaterino; Colonna, Rosella Cardigno

    2013-01-01

    The formation of new blood vessels is an essential therapeutic target in many diseases such as cancer, ischemic diseases, and chronic inflammation. In this regard, extremely low-frequency (ELF) electromagnetic fields (EMFs) seem able to inhibit vessel growth when used in a specific window of amplitude. To investigate the mechanism of anti-angiogenic action of ELF-EMFs we tested the effect of a sinusoidal magnetic field (MF) of 2 mT intensity and frequency of 50 Hz on endothelial cell models HUVEC and MS-1 measuring cell status and proliferation, motility and tubule formation ability. MS-1 cells when injected in mice determined a rapid tumor-like growth that was significantly reduced in mice inoculated with MF-exposed cells. In particular, histological analysis of tumors derived from mice inoculated with MF-exposed MS-1 cells indicated a reduction of hemangioma size, of blood-filled spaces, and in hemorrhage. In parallel, in vitro proliferation of MS-1 treated with MF was significantly inhibited. We also found that the MF-exposure down-regulated the process of proliferation, migration and formation of tubule-like structures in HUVECs. Using western blotting and immunofluorescence analysis, we collected data about the possible influence of MF on the signalling pathway activated by the vascular endothelial growth factor (VEGF). In particular, MF exposure significantly reduced the expression and activation levels of VEGFR2, suggesting a direct or indirect influence of MF on VEGF receptors placed on cellular membrane. In conclusion MF reduced, in vitro and in vivo, the ability of endothelial cells to form new vessels, most probably affecting VEGF signal transduction pathway that was less responsive to activation. These findings could not only explain the mechanism of anti-angiogenic action exerted by MFs, but also promote the possible development of new therapeutic applications for treatment of those diseases where excessive angiogenesis is involved. PMID:24244477

  19. Parasitic slow extraction of extremely weak beam from a high-intensity proton rapid cycling synchrotron

    Science.gov (United States)

    Zou, Ye; Tang, Jingyu; Yang, Zheng; Jing, Hantao

    2014-02-01

    This paper proposes a novel method to extract extremely weak beam from a high-intensity proton rapid cycling synchrotron (RCS) in the parasitic mode, while maintaining the normal fast extraction. The usual slow extraction method from a synchrotron by employing third-order resonance cannot be applied in a high-intensity RCS due to a very short flat-top at the extraction energy and the strict control on beam loss. The proposed parasitic slow extraction method moves the beam to scrape a scattering foil prior to the fast beam extraction by employing either a local orbit bump or momentum deviation or their combination, so that the halo part of the beam will be scattered. A part of the scattered particles will be extracted from the RCS and guided to the experimental area. The slow extraction process can last about a few milliseconds before the beam is extracted by the fast extraction system. The method has been applied to the RCS of China Spallation Neutron Source. With 1.6 GeV in the extraction energy, 62.5 μA in the average current and 25 Hz in the repetition rate for the RCS, the proton intensity by the slow extraction method can be up to 2×104 protons per cycle or 5×105 protons per second. The extracted beam has also a good time structure of approximately uniform in a spill which is required for many applications such as detector tests. Detailed studies including the scattering effect in the foil, the local orbit bump by the bump magnets and dispersive orbit bump by modifying the RF pattern, the multi-particle simulations by ORBIT and TURTLE codes, and some technical features for the extraction magnets are presented.

  20. High magnetic field ohmically decoupled non-contact technology

    Science.gov (United States)

    Wilgen, John [Oak Ridge, TN; Kisner, Roger [Knoxville, TN; Ludtka, Gerard [Oak Ridge, TN; Ludtka, Gail [Oak Ridge, TN; Jaramillo, Roger [Knoxville, TN

    2009-05-19

    Methods and apparatus are described for high magnetic field ohmically decoupled non-contact treatment of conductive materials in a high magnetic field. A method includes applying a high magnetic field to at least a portion of a conductive material; and applying an inductive magnetic field to at least a fraction of the conductive material to induce a surface current within the fraction of the conductive material, the surface current generating a substantially bi-directional force that defines a vibration. The high magnetic field and the inductive magnetic field are substantially confocal, the fraction of the conductive material is located within the portion of the conductive material and ohmic heating from the surface current is ohmically decoupled from the vibration. An apparatus includes a high magnetic field coil defining an applied high magnetic field; an inductive magnetic field coil coupled to the high magnetic field coil, the inductive magnetic field coil defining an applied inductive magnetic field; and a processing zone located within both the applied high magnetic field and the applied inductive magnetic field. The high magnetic field and the inductive magnetic field are substantially confocal, and ohmic heating of a conductive material located in the processing zone is ohmically decoupled from a vibration of the conductive material.

  1. Influence of Exposure to Extremely Low Frequency Magnetic Field on Neuroendocrine Cells and Hormones in Stomach of Rats

    OpenAIRE

    Hong, Min Eui; Yoon, Kyu Hyun; Jung, Yoon Yang; Lee, Tae Jin; Park, Eon Sub; Sohn, Uy Dong; Jeong, Ji Hoon

    2011-01-01

    Extremely low frequency magnetic fields (ELF-MF) have the ability to produce a variety of behavioral and physiological changes in animals. The stomach, as the most sensitive part of the neuroendocrine organ of the gastrointestinal tract, is crucial for the initiation of a full stress response against all harmful stress. Thus, the purpose of this study was to examine whether ELF-MF stimuli induce changes in the activity of neuroendocrine cells, considering their involvement in endocrine or par...

  2. Application of high magnetic fields in advanced materials processing

    Institute of Scientific and Technical Information of China (English)

    MA Yanwei; XIAO Liye; YAN Luguang

    2006-01-01

    Recently, steady magnetic fields available from cryogen-free superconducting magnets open up new ways to process materials. In this paper,the main results obtained by using a high magnetic field to process several advanced materials are reviewed. These processed objects primarily include superconducting, magnetic, metallic and nanometer-scaled materials. It has been found that a high magnetic field can effectively align grains when fabricating the magnetic and non-magnetic materials and make inclusions migrate in a molten metal. The mechanism is discussed from the theoretical viewpoint of magnetization energy.

  3. Highly-Magnetized Pulsars and Integral

    CERN Document Server

    Baring, M G; Baring, Matthew G.; Harding, Alice K.

    1998-01-01

    The complete absence of radio pulsars with periods exceeding a few seconds has lead to the popular notion of the existence of a high period death line. We have recently postulated the existence of another radio quiescence boundary at high magnetic fields ($B\\gtrsim 4\\times 10^{13}$G) in the upper portion of the period-period derivative diagram, a domain where no radio pulsars are observed. The origin of this high B boundary is also due to the suppression of magnetic pair creation, $\\gamma\\to e^{\\pm}$, but mainly because of competition with the exotic QED process of magnetic photon splitting, $\\gamma\\to\\gamma\\gamma$, coupled with ground state pair creation. This mechanism could also explain the low spectral cutoff energy of the gamma-ray pulsar PSR1509-58, which lies near the high B death-line. In this paper, we summarize the hypothesis of this new ``death line,'' and discuss some subtleties of pair suppression that relate to photon polarization and positronium formation. We identify several ways in which Inte...

  4. Permanent magnet design for high-speed superconducting bearings

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. (5519 S. Bruner, Hinsdale, IL 60521); Uherka, Kenneth L. (830 Ironwood, Frankfort, IL 60423); Abdoud, Robert G. (13 Country Oaks La., Barrington Hills, IL 60010)

    1996-01-01

    A high temperature superconducting bearing including a permanent magnet rotor levitated by a high temperature superconducting structure. The rotor preferably includes one or more concentric permanent magnet rings coupled to permanent magnet ring structures having substantially triangular and quadrangular cross-sections. Both alternating and single direction polarity magnet structures can be used in the bearing.

  5. Fifty hertz extremely low-frequency magnetic field exposure elicits redox and trophic response in rat-cortical neurons.

    Science.gov (United States)

    Di Loreto, Silvia; Falone, Stefano; Caracciolo, Valentina; Sebastiani, Pierluigi; D'Alessandro, Antonella; Mirabilio, Alessandro; Zimmitti, Vincenzo; Amicarelli, Fernanda

    2009-05-01

    Large research activity has raised around the mechanisms of interaction between extremely low-frequency magnetic fields (ELF-MFs) and biological systems. ELF-MFs may interfere with chemical reactions involving reactive oxygen species (ROS), thus facilitating oxidative damages in living cells. Cortical neurons are particularly susceptible to oxidative stressors and are also highly dependent on the specific factors and proteins governing neuronal development, activity and survival. The aim of the present work was to investigate the effects of exposures to two different 50 Hz sinusoidal ELF-MFs intensities (0.1 and 1 mT) in maturing rat cortical neurons' major anti-oxidative enzymatic and non-enzymatic cellular protection systems, membrane peroxidative damage, as well as growth factor, and cytokine expression pattern. Briefly, our results showed that ELF-MFs affected positively the cell viability and concomitantly reduced the levels of apoptotic death in rat neuronal primary cultures, with no significant effects on the main anti-oxidative defences. Interestingly, linear regression analysis suggested a positive correlation between reduced glutathione (GSH) and ROS levels in 1 mT MF-exposed cells. On this basis, our hypothesis is that GSH could play an important role in the antioxidant defence towards the ELF-MF-induced redox challenge. Moreover, the GSH-based cellular response was achieved together with a brain-derived neurotrophic factor over-expression as well as with the interleukin 1beta-dependent regulation of pro-survival signaling pathways after ELF-MF exposure.

  6. Magnetic resonance venography in consecutive patients with suspected deep vein thrombosis of the upper extremity: initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Baarslag, H.J.; Reekers, J.A. [Academic Medical Centre, Amsterdam (Netherlands). Dept. of Radiology; Beek, E.J. van [Royal Hallamshire Hospital, Sheffield (United Kingdom). Unit of Academic Radiology

    2004-02-01

    To assess the feasibility and accuracy of two magnetic resonance (MR) venography methods in a consecutive series of patients with suspected deep vein thrombosis of the upper extremity (DVTUE). Consecutive in- and outpatients who were referred for imaging of suspected DVTUE in a large teaching hospital during the period April 2001 to October 2002 were eligible for inclusion. All patients were scheduled to undergo contrast venography with the intention to perform additional MR venography. Both time-of-flight and gadolinium-enhanced 3D MR venography were scheduled. All MR imaging were interpreted independently by consensus of two experienced radiologists, who were blinded for contrast venography outcome. Patients were managed based on contrast venography only. A total of 44 patients were eligible for inclusion. Thirteen patients were excluded (5 refused consent, 2 inability to gain venous access, 2 renal failure, 4 logistic reasons). Contrast venography was performed in 31 patients, and demonstrated DVTUE in 11 patients. MR imaging was not feasible in 10 patients (4 unable to lie flat, 3 claustrophobia, 1 too large for MR scanner, 1 osteosynthesis of shoulder, 1 pacemaker). The sensitivity and specificity of TOF MRV versus Gadolinium 3D MRV was 71% and 89% versus 50% and 80%, respectively. A high number of patients were unable to undergo MR venography in this setting. Contrast-enhanced MRV did not improve diagnostic accuracy. The clinical utility of MR venography in the setting of suspected DVTUE seems disappointing.

  7. High speed functional magnetic resonance imaging

    CERN Document Server

    Gibson, A M

    2002-01-01

    The work in this thesis has been undertaken by the except where indicated by reference, within the Magnetic Resonance Centre at the University of Nottingham during the period from October 1998 to October 2001. This thesis documents the implementation and application of a novel high-speed imaging technique, the multi-slice, echo shifted, echo planar imaging technique. This was implemented on the Nottingham 3 T imaging system, for functional magnetic resonance imaging. The technique uses echo shifting over the slices in a multi-slice echo planar imaging acquisition scheme, making the echo time longer than the repetition time per slice. This allows for rapid volumar sampling of the blood oxygen level dependent effect in the human brain. The new high-speed technique was used to investigate the variability of measuring the timing differences between haemodynamic responses, at the same cortical location, to simple cued motor tasks. The technique was also used in an investigation into motor cortex functional connect...

  8. Complex magnetic susceptibility setup for spectroscopy in the extremely low-frequency range

    NARCIS (Netherlands)

    Kuipers, B.W.M.; Bakelaar, I.A.; Klokkenburg, M.; Erne, B.H.

    2008-01-01

    A sensitive balanced differential transformer was built to measure complex initial parallel magnetic susceptibility spectra in the 0.01–1000 Hz range. The alternating magnetic field can be chosen sufficiently weak that the magnetic structure of the samples is only slightly perturbed and the low freq

  9. Effect of extremely low frequency electromagnetic field exposure on sleep quality in high voltage substations.

    Science.gov (United States)

    Barsam, Tayebeh; Monazzam, Mohammad Reza; Haghdoost, Ali Akbar; Ghotbi, Mohammad Reza; Dehghan, Somayeh Farhang

    2012-11-30

    This study aims to investigate the effect of extremely low frequency electromagnetic fields exposure on sleep quality in high voltage substations (132, 230 and 400 KV) in Kerman city and the suburbs. For this purpose, the electric field intensity and magnetic flux density were measured in different parts of substations, and then the occupational exposure was estimated by averaging electric field intensity and magnetic flux density in a shift work. The cases comprised 67 workers who had been exposed to electromagnetic fields in age range of 24-57 and the controls were 110 persons the age ranged 24-50 years. Sleep quality of both groups was evaluated by the Pittsburgh Sleep Quality Index questionnaire (PSQI). Finally, these data were subjected to statistical analysis. The results indicated that 90.5% of cases and 85.3% of controls had the poor quality sleep according to PSQI (P-value=0.615). Total sleep quality score mean for the case and control groups were 10.22 ± 3.4 and 9.74 ± 3.62 (P-value=0.415) ,respectively. Meantime to fall asleep for cases(35.68 ± 26.25 min) was significantly higher than for controls (28.89 ± 20.18 min) (P-value=0.002). Cases had average sleep duration of 5.49 ± 1.31 hours, which was lower ascompared with control subjects (5.90 ± 1.67hours). Although there was a higher percentage for the case group with poor sleep quality than the control group, but no statistically significant difference was observed.

  10. Effect of extremely low frequency electromagnetic field exposure on sleep quality in high voltage substations

    Directory of Open Access Journals (Sweden)

    Barsam Tayebeh

    2012-11-01

    Full Text Available Abstract This study aims to investigate the effect of extremely low frequency electromagnetic fields exposure on sleep quality in high voltage substations (132, 230 and 400 KV in Kerman city and the suburbs. For this purpose, the electric field intensity and magnetic flux density were measured in different parts of substations, and then the occupational exposure was estimated by averaging electric field intensity and magnetic flux density in a shift work. The cases comprised 67 workers who had been exposed to electromagnetic fields in age range of 24–57 and the controls were 110 persons the age ranged 24–50 years. Sleep quality of both groups was evaluated by the Pittsburgh Sleep Quality Index questionnaire (PSQI. Finally, these data were subjected to statistical analysis. The results indicated that 90.5% of cases and 85.3% of controls had the poor quality sleep according to PSQI (P-value=0.615. Total sleep quality score mean for the case and control groups were 10.22 ± 3.4 and 9.74 ± 3.62 (P-value=0.415 ,respectively. Meantime to fall asleep for cases(35.68 ± 26.25 min was significantly higher than for controls (28.89 ± 20.18 min (P-value=0.002. Cases had average sleep duration of 5.49 ± 1.31 hours, which was lower ascompared with control subjects (5.90 ± 1.67hours. Although there was a higher percentage for the case group with poor sleep quality than the control group, but no statistically significant difference was observed.

  11. Extremely High Suction Performance Inducers for Space Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced pump inducer design technology that uses high inlet diffusion blades, operates at a very low flow coefficient, and employs a cavitation control and...

  12. The world's smallest capacitive dilatometer, for high-resolution thermal expansion and magnetostriction in high magnetic fields

    Science.gov (United States)

    Küchler, R.; Wörl, A.; Gegenwart, P.; Berben, M.; Bryant, B.; Wiedmann, S.

    2017-08-01

    For the characterization of novel quantum phases of matter, it is often required to study materials under multi-extreme conditions, in particular down to very low temperatures and in very high magnetic fields. We developed the world's smallest high-resolution capacitive dilatometer suitable for temperatures down to 10 mK and usage in high magnetic fields up to 37.5 T. Despite the extreme miniaturization, the capacitive dilatometer can resolve length changes down to 0.01 Å. This is an unprecedented resolution in a capacitive dilatometer of this compact size. Many cryogenic devices have limited space. Due to the extremely reduced cell size (3 cm3, 12 g), implementation or new applications in many of these sample space lacking devices are now possible. As an important example, the minute device can now be rotated in any standard cryostat, including dilution refrigerators or the commercial physical property measurement system. The present super compact design provides also for high resolution thermal expansion and magnetostriction measurements in a 15.2 mm diameter tube, enabling its use in the 32 mm bore, 37.5 T Bitter magnet at the High Field Magnet Laboratory in Nijmegen down to a temperature of 300 mK.

  13. High-Temperature, High-Load-Capacity Radial Magnetic Bearing

    Science.gov (United States)

    Provenza, Andrew; Montague, Gerald; Kascak, Albert; Palazzolo, Alan; Jansen, Ralph; Jansen, Mark; Ebihara, Ben

    2005-01-01

    A radial heteropolar magnetic bearing capable of operating at a temperature as high as 1,000 F (=540 C) has been developed. This is a prototype of bearings for use in gas turbine engines operating at temperatures and speeds much higher than can be withstood by lubricated rolling-element bearings. It is possible to increase the maximum allowable operating temperatures and speeds of rolling-element bearings by use of cooling-air systems, sophisticated lubrication systems, and rotor-vibration- damping systems that are subsystems of the lubrication systems, but such systems and subsystems are troublesome. In contrast, a properly designed radial magnetic bearing can suspend a rotor without contact, and, hence, without need for lubrication or for cooling. Moreover, a magnetic bearing eliminates the need for a separate damping system, inasmuch as a damping function is typically an integral part of the design of the control system of a magnetic bearing. The present high-temperature radial heteropolar magnetic bearing has a unique combination of four features that contribute to its suitability for the intended application: 1. The wires in its electromagnet coils are covered with an insulating material that does not undergo dielectric breakdown at high temperature and is pliable enough to enable the winding of the wires to small radii. 2. The processes used in winding and potting of the coils yields a packing factor close to 0.7 . a relatively high value that helps in maximizing the magnetic fields generated by the coils for a given supplied current. These processes also make the coils structurally robust. 3. The electromagnets are of a modular C-core design that enables replacement of components and semiautomated winding of coils. 4. The stator is mounted in such a manner as to provide stable support under radial and axial thermal expansion and under a load as large as 1,000 lb (.4.4 kN).

  14. Technical issues of a high-Tc superconducting bulk magnet

    Science.gov (United States)

    Fujimoto, Hiroyuki

    2000-06-01

    Superconducting magnets made of high-Tc superconductors are promising for industrial applications. It is well known that REBa2Cu3O7-x superconductors prepared by melt processes have a high critical current density, Jc, at 77 K and high magnetic fields. The materials are very promising for high magnetic field applications as a superconducting permanent/bulk magnet with liquid-nitrogen refrigeration. Light rare-earth (LRE) BaCuO bulks, compared with REBaCuO bulks, exhibit a larger Jc in high magnetic fields and a much improved irreversibility field, Hirr, at 77 K. In this study, we discuss technical issues of a high-Tc superconducting bulk magnet, namely the aspects of the melt processing for bulk superconductors, their characteristic superconducting properties and mechanical properties, and trapped field properties of a superconducting bulk magnet. One of the possible applications is a superconducting bulk magnet for the magnetically levitated (Maglev) train in the future.

  15. Effect of low-intensity extremely high frequency radiation on reproductive function in wistar rats.

    Science.gov (United States)

    Subbotina, T I; Tereshkina, O V; Khadartsev, A A; Yashin, A A

    2006-08-01

    The exposure to low-intensity extremely high frequency electromagnetic radiation during spermatogenesis was accompanied by pathological changes, which resulted in degeneration and polymorphism of spermatozoa. The number of newborn rats increased in the progeny of irradiated animals.

  16. Extreme Environment Circuit Blocks for Spacecraft Power & Propulsion System & Other High Reliability Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Chronos Technology (DIv of FMI, Inc.) proposes to design, fabricate, and deliver a performance proven, and commercially available set of extreme high operating...

  17. Identification and Plasma Diagnostics Study of Extreme Ultraviolet Transitions in Highly Charged Yttrium

    Directory of Open Access Journals (Sweden)

    Roshani Silwal

    2017-09-01

    Full Text Available Extreme ultraviolet spectra of the L-shell ions of highly charged yttrium (Y 26 + –Y 36 + were observed in the electron beam ion trap of the National Institute of Standards and Technology using a flat-field grazing-incidence spectrometer in the wavelength range of 4 nm-20 nm. The electron beam energy was systematically varied from 2.3 keV–6.0 keV to selectively produce different ionization stages. Fifty-nine spectral lines corresponding to Δ n = 0 transitions within the n = 2 and n = 3 shells have been identified using detailed collisional-radiative (CR modeling of the non-Maxwellian plasma. The uncertainties of the wavelength determinations ranged between 0.0004 nm and 0.0020 nm. Li-like resonance lines, 2s– 2 p 1 / 2 and 2s–2 p 3 / 2 , and the Na-like D lines, 3s– 3 p 1 / 2 and 3s– 3 p 3 / 2 , have been measured and compared with previous measurements and calculations. Forbidden magnetic dipole (M1 transitions were identified and analyzed for their potential applicability in plasma diagnostics using large-scale CR calculations including approximately 1.5 million transitions. Several line ratios were found to show strong dependence on electron density and, hence, may be implemented in the diagnostics of hot plasmas, in particular in fusion devices.

  18. Extremely high-power tongue projection in plethodontid salamanders

    NARCIS (Netherlands)

    Deban, S.M.; O'Reilly, J.C.; Dicke, U.; Leeuwen, van J.L.

    2007-01-01

    Many plethodontid salamanders project their tongues ballistically at high speed and for relatively great distances. Capturing evasive prey relies on the tongue reaching the target in minimum time, therefore it is expected that power production, or the rate of energy release, is maximized during tong

  19. Spontaneous magnetization in high-density quark matter

    DEFF Research Database (Denmark)

    Tsue, Yasuhiko; da Providência, João; Providência, Constanca;

    2015-01-01

    It is shown that spontaneous magnetization occurs due to the anomalous magnetic moments of quarks in high-density quark matter under the tensor-type four-point interaction. The spin polarized condensate for each flavor of quark appears at high baryon density, which leads to the spontaneous...... magnetization due to the anomalous magnetic moments of quarks. The implications for the strong magnetic field in compact stars is discussed....

  20. High-Gain Magnetized Inertial Fusion

    Science.gov (United States)

    Slutz, Stephen A.; Vesey, Roger A.

    2012-01-01

    Magnetized inertial fusion (MIF) could substantially ease the difficulty of reaching plasma conditions required for significant fusion yields, but it has been widely accepted that the gain is not sufficient for fusion energy. Numerical simulations are presented showing that high-gain MIF is possible in cylindrical liner implosions based on the MagLIF concept [S. A. Slutz et al Phys. Plasmas 17, 056303 (2010)PHPAEN1070-664X10.1063/1.3333505] with the addition of a cryogenic layer of deuterium-tritium (DT). These simulations show that a burn wave propagates radially from the magnetized hot spot into the surrounding much denser cold DT given sufficient hot-spot areal density. For a drive current of 60 MA the simulated gain exceeds 100, which is more than adequate for fusion energy applications. The simulated gain exceeds 1000 for a drive current of 70 MA.

  1. High Radiation Environment Nuclear Fragment Separator Magnet

    Energy Technology Data Exchange (ETDEWEB)

    Kahn, Stephen [Muons, Inc., Batavia, IL (United States); Gupta, Ramesh [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-01-31

    Superconducting coils wound with HTS conductor can be used in magnets located in a high radiation environment. NbTi and Nb3Sn superconductors must operate at 4.5 K or below where removal of heat is less efficient. The HTS conductor can carry significant current at higher temperatures where the Carnot efficiency is significantly more favorable and where the coolant heat capacity is much larger. Using the HTS conductor the magnet can be operated at 40 K. This project examines the use of HTS conductor for the Michigan State University Facility For Rare Isotope Beams (FRIB) fragment separator dipole magnet which bends the beam by 30° and is located in a high radiation region that will not be easily accessible. Two of these magnets are needed to select the chosen isotope. There are a number of technical challenges to be addressed in the design of this magnet. The separator dipole is 2 m long and subtends a large angle. The magnet should keep a constant transverse field profile along its beam reference path. Winding coils with a curved inner segment is difficult as the conductor will tend to unwind during the process. In the Phase I project two approaches to winding the conductor were examined. The first was to wind the coils with curved sections on the inner and outer segments with the inner segment wound with negative curvature. The alternate approach was to use a straight segment on the inner segment to avoid negative curvature. In Phase I coils with a limited number of turns were successfully wound and tested at 77 K for both coil configurations. The Phase II program concentrated on the design, coil winding procedures, structural analysis, prototyping and testing of an HTS curved dipole coil at 40 K with a heat load representative of the radiation environment. One of the key criteria of the design of this magnet is to avoid the use of organic materials that would degrade rapidly in radiation. The Lorentz forces expected from the coils interacting with the

  2. High performance magnetic bearing systems using high temperature superconductors

    Science.gov (United States)

    Abboud, Robert G.

    1998-01-01

    A magnetic bearing apparatus and a method for providing at least one stabilizing force in a magnetic bearing structure with a superconducting magnetic assembly and a magnetic assembly, by providing a superconducting magnetic member in the superconducting magnetic assembly with a plurality of domains and arranging said superconducting magnetic member such that at least one domain has a domain C-axis vector alignment angularly disposed relative to a reference axis of the magnetic member in the magnetic assembly.

  3. High Energy Ion Acceleration by Extreme Laser Radiation Pressure

    Science.gov (United States)

    2017-03-14

    was used instead. This code makes the assumption that the background ion and electron behaviour can be approximated with a fluid model whilst...electron behaviour occurring from this aperture was also published in High Power Laser Science and Engineering [4]. A significant breakthrough was also...acceleration to transparency. This was published in Physics of Plasmas [12]. Through one- dimensional modelling of the interaction, it was also

  4. The extremely high stability of carbofuran pesticide in acidic media

    Directory of Open Access Journals (Sweden)

    Tomašević Anđelka V.

    2007-01-01

    Full Text Available Environment friendly iron catalysts were applied in the decomposition reactions of some toxic compounds like phenol, methomyl and corbofuran pesticide. The applied catalytic processes belong to photo-Fenton reactions. Heterogeneous iron catalysts showed significant activity in phenol and methomyl conversion, however, these catalysts were completely inactive in destruction of carbofuran molecule, even in the catalytic reaction promoted with UV light at high temperature.

  5. Adaptation potential of naturally ventilated barns to high temperature extremes: The OptiBarn project

    Science.gov (United States)

    Menz, Christoph

    2016-04-01

    Climate change interferes with various aspects of the socio-economic system. One important aspect is its influence on animal husbandry, especially dairy faming. Dairy cows are usually kept in naturally ventilated barns (NVBs) which are particular vulnerable to extreme events due to their low adaptation capabilities. An effective adaptation to high outdoor temperatures for example, is only possible under certain wind and humidity conditions. High temperature extremes are expected to increase in number and strength under climate change. To assess the impact of this change on NVBs and dairy cows also the changes in wind and humidity needs to be considered. Hence we need to consider the multivariate structure of future temperature extremes. The OptiBarn project aims to develop sustainable adaptation strategies for dairy housings under climate change for Europe, by considering the multivariate structure of high temperature extremes. In a first step we identify various multivariate high temperature extremes for three core regions in Europe. With respect to dairy cows in NVBs we will focus on the wind and humidity field during high temperature events. In a second step we will use the CORDEX-EUR-11 ensemble to evaluate the capability of the RCMs to model such events and assess their future change potential. By transferring the outdoor conditions to indoor climate and animal wellbeing the results of this assessment can be used to develop technical, architectural and animal specific adaptation strategies for high temperature extremes.

  6. Occupational exposure to intermediate frequency and extremely low frequency magnetic fields among personnel working near electronic article surveillance systems.

    Science.gov (United States)

    Roivainen, Päivi; Eskelinen, Tuomo; Jokela, Kari; Juutilainen, Jukka

    2014-05-01

    Cashiers are potentially exposed to intermediate frequency (IF) magnetic fields at their workplaces because of the electronic article surveillance (EAS) systems used in stores to protect merchandise against theft. This study aimed at investigating occupational exposure of cashiers to IF magnetic fields in Finnish stores. Exposure to extremely low frequency (ELF) magnetic fields was also evaluated because cashiers work near various devices operating with 50 Hz electric power. The peak magnetic flux density was measured for IF magnetic fields, and was found to vary from 0.2 to 4 µT at the cashier's seat. ELF magnetic fields from 0.03 to 4.5 µT were found at the cashier's seat. These values are much lower than exposure limits. However, according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) occupational reference levels for IF magnetic fields (141 µT for the peak field) were exceeded in some cases (maximum 189 µT) for short periods of time when cashiers walked through the EAS gates. As the ICNIRP reference levels do not define any minimum time for exposure, additional investigations are recommended to determine compliance with basic restrictions. Even if the basic restrictions are not exceeded, persons working near EAS devices represent an exceptional group of workers with respect to exposure to electromagnetic fields. This group could serve as a basis for epidemiological studies addressing possible health effects of IF magnetic fields. Compliance with the reference levels for IF fields was evaluated using both broadband measurement of peak fields and the ICNIRP summation rule for multiple frequencies. The latter was generally more conservative, and the difference between the two methods was large (>10-fold) for EAS systems using a 58 kHz signal with complex waveform. This indicates that the ICNIRP multiple frequency rule can be unnecessarily conservative when measuring complex waveforms.

  7. High Performance Multivariate Visual Data Exploration for Extremely Large Data

    Energy Technology Data Exchange (ETDEWEB)

    Rubel, Oliver; Wu, Kesheng; Childs, Hank; Meredith, Jeremy; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Ahern, Sean; Weber, Gunther H.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes; Prabhat,

    2008-08-22

    One of the central challenges in modern science is the need to quickly derive knowledge and understanding from large, complex collections of data. We present a new approach that deals with this challenge by combining and extending techniques from high performance visual data analysis and scientific data management. This approach is demonstrated within the context of gaining insight from complex, time-varying datasets produced by a laser wakefield accelerator simulation. Our approach leverages histogram-based parallel coordinates for both visual information display as well as a vehicle for guiding a data mining operation. Data extraction and subsetting are implemented with state-of-the-art index/query technology. This approach, while applied here to accelerator science, is generally applicable to a broad set of science applications, and is implemented in a production-quality visual data analysis infrastructure. We conduct a detailed performance analysis and demonstrate good scalability on a distributed memory Cray XT4 system.

  8. High-temperature superconducting undulator magnets

    Science.gov (United States)

    Kesgin, Ibrahim; Kasa, Matthew; Ivanyushenkov, Yury; Welp, Ulrich

    2017-04-01

    This paper presents test results on a prototype superconducting undulator magnet fabricated using 15% Zr-doped rare-earth barium copper oxide high temperature superconducting (HTS) tapes. On an 11-pole magnet we demonstrate an engineering current density, J e, of more than 2.1 kA mm‑2 at 4.2 K, a value that is 40% higher than reached in comparable devices wound with NbTi-wire, which is used in all currently operating superconducting undulators. A novel winding scheme enabling the continuous winding of tape-shaped conductors into the intricate undulator magnets as well as a partial interlayer insulation procedure were essential in reaching this advance in performance. Currently, there are rapid advances in the performance of HTS; therefore, achieving even higher current densities in an undulator structure or/and operating it at temperatures higher than 4.2 K will be possible, which would substantially simplify the cryogenic design and reduce overall costs.

  9. Hybrid Superconducting Magnetic Bearing (HSMB) for high load devices

    Science.gov (United States)

    McMichael, C. K.; Ma, K. B.; Lamb, M. A.; Lin, M. W.; Chow, L.; Meng, R. L.; Hor, P. H.; Chu, W. K.

    1992-05-01

    Lifting capacities greater than 41 N/cm(exp 2) (60 psi) at 77 K have been achieved with a new type of levitation (hybrid) using a combination of permanent magnets and high quality melt-mixtured YBa2Cu3O(7-delta) (YBCO). The key concept of the hybrid superconducting magnetic bearing (HSMB) is the use of strong magnetic repulsion and attraction from permanent magnets for high levitation or suspension forces in conjunction with a superconductor's flux pinning characteristics to counteract the inherent instabilities in a system consisting of magnets only. To illustrate this concept, radial and axial forces between magnet/superconductor, magnet/magnet, and magnet/superconductor/magnet, were measured and compared for the thrust bearing configuration

  10. Spin-resolved photoelectron spectroscopy using femtosecond extreme ultraviolet light pulses from high-order harmonic generation

    Science.gov (United States)

    Plötzing, M.; Adam, R.; Weier, C.; Plucinski, L.; Eich, S.; Emmerich, S.; Rollinger, M.; Aeschlimann, M.; Mathias, S.; Schneider, C. M.

    2016-04-01

    The fundamental mechanism responsible for optically induced magnetization dynamics in ferromagnetic thin films has been under intense debate since almost two decades. Currently, numerous competing theoretical models are in strong need for a decisive experimental confirmation such as monitoring the triggered changes in the spin-dependent band structure on ultrashort time scales. Our approach explores the possibility of observing femtosecond band structure dynamics by giving access to extended parts of the Brillouin zone in a simultaneously time-, energy- and spin-resolved photoemission experiment. For this purpose, our setup uses a state-of-the-art, highly efficient spin detector and ultrashort, extreme ultraviolet light pulses created by laser-based high-order harmonic generation. In this paper, we present the setup and first spin-resolved spectra obtained with our experiment within an acquisition time short enough to allow pump-probe studies. Further, we characterize the influence of the excitation with femtosecond extreme ultraviolet pulses by comparing the results with data acquired using a continuous wave light source with similar photon energy. In addition, changes in the spectra induced by vacuum space-charge effects due to both the extreme ultraviolet probe- and near-infrared pump-pulses are studied by analyzing the resulting spectral distortions. The combination of energy resolution and electron count rate achieved in our setup confirms its suitability for spin-resolved studies of the band structure on ultrashort time scales.

  11. Hazard zoning around electric substations of petrochemical industries by stimulation of extremely low-frequency magnetic fields.

    Science.gov (United States)

    Hosseini, Monireh; Monazzam, Mohammad Reza; Farhang Matin, Laleh; Khosroabadi, Hossein

    2015-05-01

    Electromagnetic fields in recent years have been discussed as one of the occupational hazards at workplaces. Hence, control and assessment of these physical factors is very important to protect and promote the health of employees. The present study was conducted to determine hazard zones based on assessment of extremely low-frequency magnetic fields at electric substations of a petrochemical complex in southern Iran, using the single-axis HI-3604 device. In measurement of electromagnetic fields by the single-axis HI-3604 device, the sensor screen should be oriented in a way to be perpendicular to the field lines. Therefore, in places where power lines are located in different directions, it is required to keep the device towards three axes of x, y, and z. For further precision, the measurements should be repeated along each of the three axes. In this research, magnetic field was measured, for the first time, in three axes of x, y, and z whose resultant value was considered as the value of magnetic field. Measurements were done based on IEEE std 644-1994. Further, the spatial changes of the magnetic field surrounding electric substations were stimulated using MATLAB software. The obtained results indicated that the maximum magnetic flux density was 49.90 μT recorded from boiler substation, while the minimum magnetic flux density of 0.02 μT was measured at the control room of the complex. As the stimulation results suggest, the spaces around incoming panels, transformers, and cables were recognized as hazardous zones of indoor electric substations. Considering the health effects of chronic exposure to magnetic fields, it would be possible to minimize exposure to these contaminants at workplaces by identification of risky zones and observation of protective considerations.

  12. A multicenter reliability study of extremity-magnetic resonance imaging in the longitudinal evaluation of rheumatoid arthritis

    DEFF Research Database (Denmark)

    Conaghan, Philip G; Ejbjerg, Bo; Lassere, Marissa

    2007-01-01

    There are limited data on the reliability of extremity magnetic resonance imaging (E-MRI) in the longitudinal evaluation of rheumatoid arthritis (RA). Our aim was to assess the interreader reliability of the OMERACT RA MRI score in the assessment of change in disease activity and bone erosion...... scores using 0.2 T E-MRI hand and wrist images from 2 timepoints, evaluated by 3 readers at different international centers. The intraclass correlation coefficients and smallest detectable difference results for the change scores were generally good for erosions and synovitis, but were not acceptable...

  13. The effects of exposure to extremely low-frequency magnetic field and amphetamine on the reduced glutathione in the brain.

    Science.gov (United States)

    Jelenković, Ankica; Janać, Branka; Pesić, Vesna; Jovanović, Marina D; Vasiljević, Ivana; Prolić, Zlatko

    2005-06-01

    Continuous exposure to extremely low-frequency magnetic field (ELF-MF, 50 Hz, 0.5 mT) alone and combined with D-amphetamine (1.5 mg/kg) affected the reduced glutathione content in brain regions of rats. Compared to sham-exposed rats, the glutathione content in the forebrain cortex of the ELF-MF-exposed rats decreased (P glutathione content was increased in the brain stem and cerebellum (P glutathione changes observed. The changes are not uniform in the brain regions examined.

  14. Prospects of hydroacoustic detection of ultra-high and extremely high energy cosmic neutrinos

    Science.gov (United States)

    Dedenko, L. G.; Karlik, Ya. S.; Learned, J. G.; Svet, V. D.; Zheleznykh, I. M.

    2001-07-01

    The prospects of construction of deep underwater neutrino telescopes in the world's oceans for the goals of ultra-high and super-high energy neutrino astrophysics (astronomy) using acoustic technologies are reviewed. The effective detection volume of the acoustic neutrino telescopes can be far greater than a cubic kilometer for extreme energies. In recent years, it was proposed that an existing hydroacoustic array of 2400 hydrophones in the Pacific Ocean near Kamchatka Peninsula could be used as a test base for an acoustic neutrino telescope SADCO (Sea-based Acoustic Detector of Cosmic Objects) which should be capable of detecting acoustic signals produced in water by the cosmic neutrinos with energies 1019-21 eV (e.g., topological defect neutrinos). We report on simulations of super-high energy electron-hadron and electron-photon cascades with the Landau-Pomeranchuk-Migdal effect taken into account. Acoustic signals emitted by neutrino-induced cascades with energies 1020-21 eV were calculated. The possibilities of using a converted hydroacoustic station MG-10 (MG-10M) of 132 hydrophones as a basic module for a deep water acoustic neutrino detector with the threshold detection energy 1015 eV in the Mediterranean Sea are analyzed (with the aim of searching for neutrinos with energies 1015-16 eV from Active Galactic Nuclei). .

  15. Influence of extremely low frequency magnetic fields on Ca2+ signaling and NMDA receptor functions in rat hippocampus.

    Science.gov (United States)

    Manikonda, Pavan K; Rajendra, P; Devendranath, D; Gunasekaran, B; Channakeshava; Aradhya, R S S; Sashidhar, R B; Subramanyam, C

    2007-02-14

    Extremely low frequency (ELFelectromagnetic fields affect several neuronal activities including memory. Because ELF magnetic fields cause altered Ca(2+) homeostasis in neural tissues, we examined their influence on Ca(2+) signaling enzymes in hippocampus and related them with NMDA receptor functions. Hippocampal regions were obtained from brains of 21-day-old rats that were exposed for 90 days to 50Hz magnetic fields at 50 and 100 microT intensities. In comparison to controls, ELF exposure caused increased intracellular Ca(2+) levels concomitant with increased activities of Ca(2+)-dependent protein kinase C (PKC), cAMP-dependent protein kinase and calcineurin as well as decreased activity of Ca(2+)-calmodulin-dependent protein kinase in hippocampal regions. Simultaneous ligand-binding studies revealed decreased binding to N-methyl-D-aspartic acid (NMDA) receptors. The combined results suggest that perturbed neuronal functions caused by ELF exposure may involve altered Ca(2+) signaling events contributing to aberrant NMDA receptor activities.

  16. Three-dimensional extremely-short optical pulses in carbon nanotube arrays in the presence of an external magnetic field

    Science.gov (United States)

    Zhukov, Alexander V.; Bouffanais, Roland; Belonenko, Mikhail B.; Galkina, Elena N.

    2016-12-01

    In this paper, we study the behavior of three-dimensional extremely-short optical pulses propagating in a system made of carbon nanotubes in the presence of an external magnetic field applied perpendicular both to the nanotube axis and to the direction of propagation of the pulse. The evolution of the electromagnetic field is classically derived on the basis of the Maxwell’s equations. The electronic system of carbon nanotubes is considered in the low-temperature approximation. Our analysis reveals the novel and unique ability of controlling the shape of propagating short optical pulses by tuning the intensity of the applied magnetic field. This effect paves the way for the possible development of innovative applications in optoelectronics.

  17. High performance hybrid magnetic structure for biotechnology applications

    Science.gov (United States)

    Humphries, David E [El Cerrito, CA; Pollard, Martin J [El Cerrito, CA; Elkin, Christopher J [San Ramon, CA

    2009-02-03

    The present disclosure provides a high performance hybrid magnetic structure made from a combination of permanent magnets and ferromagnetic pole materials which are assembled in a predetermined array. The hybrid magnetic structure provides means for separation and other biotechnology applications involving holding, manipulation, or separation of magnetic or magnetizable molecular structures and targets. Also disclosed are further improvements to aspects of the hybrid magnetic structure, including additional elements and for adapting the use of the hybrid magnetic structure for use in biotechnology and high throughput processes.

  18. Improving magnet designs with high and low field regions

    CERN Document Server

    Bjørk, R; Smith, A; Pryds, N

    2014-01-01

    A general scheme for increasing the difference in magnetic flux density between a high and a low magnetic field region by removing unnecessary magnet material is presented. This is important in, e.g., magnetic refrigeration where magnet arrays has to deliver high field regions in close proximity to low field regions. Also, a general way to replace magnet material with a high permeability soft magnetic material where appropriate is discussed. As an example these schemes are applied to a two dimensional concentric Halbach cylinder design resulting in a reduction of the amount of magnet material used by 42% while increasing the difference in flux density between a high and a low field region by 45%.

  19. Clinical Implications of Diffuse Excessive High Signal Intensity (DEHSI on Neonatal MRI in School Age Children Born Extremely Preterm.

    Directory of Open Access Journals (Sweden)

    Lina Broström

    Full Text Available Magnetic resonance imaging (MRI of the brain carried out during the neonatal period shows that 55-80% of extremely preterm infants display white matter diffuse excessive high signal intensity (DEHSI. Our aim was to study differences in developmental outcome at the age of 6.5 years in children born extremely preterm with and without DEHSI.This was a prospective cohort study of 83 children who were born in Stockholm, Sweden, between 2004 and 2007, born at gestational age of < 27 weeks + 0 days and who underwent an MRI scan of their brain at term equivalent age. The outcome measures at 6.5 years included testing 66 children with the modified Touwen neurology examination, the Movement Assessment Battery for Children 2, the Wechsler Intelligence Scale for Children-Fourth Edition, Beery Visual-motor Integration test-Sixth Edition, and the Strengths and Difficulties Questionnaire. Group-wise comparisons were done between children with and without DEHSI using Student t-test, Mann Whitney U test, Chi square test and regression analysis.DEHSI was detected in 39 (59% of the 66 children who were assessed at 6.5 years. The presence of DEHSI was not associated with mild neurological dysfunction, scores on M-ABC assessment, cognition, visual-motor integration, or behavior at 6.5 years.The presence of qualitatively defined DEHSI on neonatal MRI did not prove to be a useful predictor of long-term impairment in children born extremely preterm.

  20. Enhanced Energy Density in Permanent Magnets using Controlled High Magnetic Field during Processing

    Energy Technology Data Exchange (ETDEWEB)

    Rios, Orlando [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carter, Bill [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Constantinides, Steve [Arnold Magnetic Technologies, Rochester, NY (United States)

    2016-05-05

    This ORNL Manufacturing Demonstraction Facility (MDF) technical collaboration focused on the use of high magnetic field processing (>2Tesla) using energy efficient large bore superconducting magnet technology and high frequency electromagnetics to improve magnet performance and reduce the energy budget associated with Alnico thermal processing. Alnico, alloys containing Al, Ni, Co and Fe, represent a class of functional nanostructured alloys, and show the greatest potential for supplementing or replacing commercial Nd-based rare-earth alloy magnets.

  1. Influence of extremely low frequency magnetic field on total protein and –SH groups concentrations in liver homogenates

    Directory of Open Access Journals (Sweden)

    Elżbieta Ciejka

    2014-10-01

    Full Text Available Background: Free radicals are atoms, molecules or their fragments, whose excess leads to the development of oxidative stress, the cause of many neoplastic, neurodegenerative and inflammatory diseases, as well as aging of organisms. Industrial pollution, tobacco smoke, ionizing radiation, ultrasound and magnetic fields are the major exogenous sources of free radicals. The low frequency magnetic field is commonly applied in physiotherapy. The aim of the present study was to evaluate the effect of extremely low frequency magnetic field (ELF-MF on the concentration of sulfhydryl groups (–SH and proteins in liver tissues of experimental animals depending on the time of exposure to the field. Material and Methods: Twenty one Sprague-Dawley male rats, aged 3–4 months were randomly divided into 3 experimental groups (each containing 7 animals: controls (group I, the rats exposed to ELF-MF of 40 Hz, 7 mT (this kind of the ELF-MF is mostly used in magnetotherapy, 30 min/day for 2 weeks (group II and the rats exposed to 40 Hz, 7 mT for 60 min/day for 2 weeks (group III. The concentrations of proteins and sulfhydryl groups in the liver tissues were determined after exposure to magnetic fields. Results: Exposure to low magnetic field: 40 Hz, 7 mT for 30 min/day and 60 min/day for 2 weeks caused a significant increase in the concentration of –SH groups and total protein levels in the liver tissues. Conclusions: The study results suggest that exposure to magnetic fields leads to the development of adaptive mechanisms to maintain the balance in the body oxidation-reduction and in the case of the studied parameters does not depend on the time of exposure. Med Pr 2014;65(5:639–644

  2. Effect of extremely weak pulsed magnetic field type Bemer 3000 on ratings of perceived exertion

    Directory of Open Access Journals (Sweden)

    D Gazurek

    2008-06-01

    Full Text Available The aim of this study was to examine whether is an influence of the exposition on different inductions of magnetic fields on rating of perceived exertion during 10 min long standardised physical cycloergometer exercise. The investigation was performed in 40 healthy, non-smoking, fit men, mean age 202. The participants were randomly attributed to 4 groups, each including 10 subjects. The first one (group E18 consisted of subjects exposed to the magnetic field with the intensity of 18 μT, the second one (group E64 exposed to the magnetic field with the intensity of 64 μT. Two control groups were formed to accompany these exposed to the magnetic field. In these placebo groups (S-T subjects were not exposed to the magnetic field (so called false therapy, „sham treatment”. The study consisted of 4 steps: pilot study, the first endurance test, exposure to the magnetic field, the second endurance test. The aim of the pilot study was to define subjective feelings of the participant during the effort, his reaction to the effort and also practical familiarization with the character and rules of the endurance test and Borg scale interpretation during 10 min of endurance cycloergometer test. The first endurance test was performed two days after the pilot study with the same rules and its goal was to measure the level of tiredness according to the Borg scale during 10 min long standardised physical effort. The second endurance test was performed according to the same rules as the first one and its goal was to analyse the effect of 20 exposures to the magnetic field with the intensity of 18 and 64 μT repeated daily on the perception of tiredness increase as expressed in the Borg scale when performing 10 min long standardised physical effort. In subjects exposed to 18 μT magnetic field neither changes in the perception of fatigue nor changes in the heart rate at particular levels of the Borg scale have been observed. When compared with both control

  3. Magnetic and magnetothermal properties and the magnetic phase diagram of high purity single crystalline terbium along the easy magnetization direction.

    Science.gov (United States)

    Zverev, V I; Tishin, A M; Chernyshov, A S; Mudryk, Ya; Gschneidner, K A; Pecharsky, V K

    2014-02-12

    The magnetic and magnetothermal properties of a high purity terbium single crystal have been re-investigated from 1.5 to 350 K in magnetic fields ranging from 0 to 75 kOe using magnetization, ac magnetic susceptibility and heat capacity measurements. The magnetic phase diagram has been refined by establishing a region of the fan-like phase broader than reported in the past, by locating a tricritical point at 226 K, and by a more accurate definition of the critical fields and temperatures associated with the magnetic phases observed in Tb.

  4. Magnetic resonance imaging of peripheral nerve tumours in the upper extremity

    DEFF Research Database (Denmark)

    Nilsson, Jessica; Sandberg, Kristina; Søe Nielsen, Niels;

    2009-01-01

    extremity. Medical records of 19 patients (20 MRI examinations) with 29 histopathologically verified benign nerve tumours were examined retrospectively. In 12/20 cases MRI suggested a correct diagnosis of the type of nerve tumour. An additional 3/20 cases had an uncertain diagnosis, but nerve relations...

  5. Functionally interpretable local coordinate systems for the upper extremity using inertial & magnetic measurement systems.

    Science.gov (United States)

    de Vries, W H K; Veeger, H E J; Cutti, A G; Baten, C; van der Helm, F C T

    2010-07-20

    Inertial Magnetic Measurement Systems (IMMS) are becoming increasingly popular by allowing for measurements outside the motion laboratory. The latest models enable long term, accurate measurement of segment motion in terms of joint angles, if initial segment orientations can accurately be determined. The standard procedure for definition of segmental orientation is based on the measurement of positions of bony landmarks (BLM). However, IMMS do not deliver position information, so an alternative method to establish IMMS based, anatomically understandable segment orientations is proposed. For five subjects, IMMS recordings were collected in a standard anatomical position for definition of static axes, and during a series of standardized motions for the estimation of kinematic axes of rotation. For all axes, the intra- and inter-individual dispersion was estimated. Subsequently, local coordinate systems (LCS) were constructed on the basis of the combination of IMMS axes with the lowest dispersion and compared with BLM based LCS. The repeatability of the method appeared to be high; for every segment at least two axes could be determined with a dispersion of at most 3.8 degrees. Comparison of IMMS based with BLM based LCS yielded compatible results for the thorax, but less compatible results for the humerus, forearm and hand, where differences in orientation rose to 17.2 degrees. Although different from the 'gold standard' BLM based LCS, IMMS based LCS can be constructed repeatable, enabling the estimation of segment orientations outside the laboratory. A procedure for the definition of local reference frames using IMMS is proposed. 2010 Elsevier Ltd. All rights reserved.

  6. Calculating magnetic shielding effectiveness for high-power dc comparator by magnetic circuit method

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-wei; REN Shi-yan

    2007-01-01

    Magnetic shielding is very important in the design of a high-power dc comparator. This paper addressed the application of magnetic circuit method to calculate the magnetic shielding effectiveness of high-power dc comparators when an external radial magnetic field is added. The mathematical relationship between the magnetic shielding effectiveness and the parameters of the magnetic shielding body were obtained. To verify the validity of the calculation method, we developped a procedure to measure the magnetic shielding effectiveness of the magnetic body by measuring the induction voltage of the detection winding instead of the magnetic intensity at a point in the magnetic shielding body, making the manipulation much easier. The result calculated with the magnetic circuit method turns out to be closer to the measured one compared with that calculated with a conventional algorithm proposed by Ren, suggesting that the magnetic circuit method is an applicable tool for estimating the toroidal cavity magnetic shielding effectiveness of a heavy current comparator when a radial magnetic field is added.

  7. Levitation performance of the magnetized bulk high- Tc superconducting magnet with different trapped fields

    Science.gov (United States)

    Liu, W.; Wang, J. S.; Liao, X. L.; Zheng, S. J.; Ma, G. T.; Zheng, J.; Wang, S. Y.

    2011-03-01

    To a high- Tc superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high- Tc superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets.

  8. Wide Temperature Magnetization Characteristics of Transverse Magnetically Annealed Amorphous Tapes for High Frequency Aerospace Magnetics

    Science.gov (United States)

    Niedra, Janis M.; Schwarze, Gene E.

    1999-01-01

    100 kHz magnetization properties of sample transverse magnetically annealed, cobalt-based amorphous and iron-based nanocrystalline tape wound magnetic cores are presented over the temperature range of -150 C to 150 C, at selected values of B(sub peak). Frequency resolved characteristics are given over the range of 50 kHz to 1 MHz, but at B(sub peak) = 0.1 T and 50 C only. Basic exciting winding current and induced voltage data were taken on bare toroidal cores, in a standard type measurement setup. A linear permeability model, which represents the core by a parallel L-R circuit, is used to interpret and present the magnetization characteristics and several figures of merit applicable to inductor materials are reviewed. The 100 kHz permeability thus derived decreases with increasing temperature for the Fe-based, nanocrystalline material, but increases roughly linearly with temperature for the two Co-based materials, as long as B(sub peak) is sufficiently low to avoid saturation effects. Due to the high permeabilities, rather low values of the 'quality factor' Q, from about 20 to below unity, were obtained over the frequency range of 50 kHz to 1 MHz (50 C, B(sub peak) = 0.1 T). Therefore these cores must be gapped in order to make up high Q or high current inductors. However, being rugged, low core loss materials with flat B-H loop characteristics, they may provide new solutions to specialty inductor applications.

  9. How extreme are extremes?

    Science.gov (United States)

    Cucchi, Marco; Petitta, Marcello; Calmanti, Sandro

    2016-04-01

    High temperatures have an impact on the energy balance of any living organism and on the operational capabilities of critical infrastructures. Heat-wave indicators have been mainly developed with the aim of capturing the potential impacts on specific sectors (agriculture, health, wildfires, transport, power generation and distribution). However, the ability to capture the occurrence of extreme temperature events is an essential property of a multi-hazard extreme climate indicator. Aim of this study is to develop a standardized heat-wave indicator, that can be combined with other indices in order to describe multiple hazards in a single indicator. The proposed approach can be used in order to have a quantified indicator of the strenght of a certain extreme. As a matter of fact, extremes are usually distributed in exponential or exponential-exponential functions and it is difficult to quickly asses how strong was an extreme events considering only its magnitude. The proposed approach simplify the quantitative and qualitative communication of extreme magnitude

  10. Advances in high-resolution nuclear magnetic resonance methods in inhomogeneous magnetic fields using intermolecular multiple quantum coherences

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Strong and extremely homogeneous static magnetic field is usually required for high-resolution nu-clear magnetic resonance (NMR). However, in the cases of in vivo and so on, the magnetic field inho-mogeneity owing to magnetic susceptibility variation in samples is unavoidable and hard to eliminate by conventional methods such as shimming. Recently, intermolecular multiple quantum coherences (iMQCs) have been employed to eliminate inhomogeneous broadening and obtain high-resolution NMR spectra, especially for in vivo samples. Compared to other high-resolution NMR methods, iMQC method exhibits its unique feature and advantage. It simultaneously holds information of chemical shifts, multiplet structures, coupling constants, and relative peak areas. All the information is often used to analyze and characterize molecular structures in conventional one-dimensional NMR spec-troscopy. In this work, recent technical developments including our results in this field are summarized; the high-resolution mechanism is analyzed and comparison with other methods based on interactions between spins is made; comments on the current situation and outlook on the research directions are also made.

  11. Electromagnet configurations for extreme attitude testing in magnetic suspension and balance systems

    Science.gov (United States)

    Britcher, C. P.

    1980-01-01

    The inclusion of adequate versatility into the electromagnet array configuration requires sizing the electromagnets to satisfy particular absolute force and moment requirements. Magnetic performance of a permanent magnet model core, air cored electromagnet may easily and reliably be computed by using the FORCE program which calculates model forces and moments via representations of the model as an assembly of dipoles and the electromagnets as an assembly of line currents. Some aspects of the performance of an ellipsoidal iron cored model may be inferred from the above under certain circumstances.

  12. Probing High Temperature Superconductors with Magnetometry in Ultrahigh Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lu [Univ. of Michigan, Ann Arbor, MI (United States)

    2017-07-26

    The objective of this research is to investigate the high-field magnetic properties of high temperature superconductors, materials that conduct electricity without loss. A technique known as high-resolution torque magnetometry that was developed to directly measure the magnetization of high temperature superconductors. This technique was implemented using the 65 Tesla pulsed magnetic field facility that is part of the National High Magnetic Field Laboratory at Los Alamos National Laboratory. This research addressed unanswered questions about the interplay between magnetism and superconductivity, determine the electronic structure of high temperature superconductors, and shed light on the mechanism of high temperature superconductivity and on potential applications of these materials in areas such as energy generation and power transmission. Further applications of the technology resolve the novel physical phenomena such as correlated topological insulators, and spin liquid state in quantum magnets.

  13. Magnetization and magnetostriction in highly magnetostrictive materials

    Energy Technology Data Exchange (ETDEWEB)

    Thoelke, Jennifer Beth [Iowa State Univ., Ames, IA (United States)

    1993-05-26

    The majority of this research has been in developing a model to describe the magnetostrictive properties of Terfenol-D, Tbsub>1-xDyxFey (x = 0.7-0.75 and y = 1.8--2.0), a rare earth-iron alloy which displays much promise for use in device applications. In the first chapter an introduction is given to the phenomena of magnetization and magnetostriction. The magnetic processes responsible for the observed magnetic properties of materials are explained. An overview is presented of the magnetic properties of rare earths, and more specifically the magnetic properties of Terfenol-D. In the second chapter, experimental results are presented on three composition of Tb< with x = 0.7, y= 1.9, 1.95, and x= 0.73, y= 1.95. The data were taken for various levels of prestress to show the effects of composition and microstructure on the magnetic and magnetostrictive properties of Terfenol-D. In the third chapter, a theoretical model is developed based on the rotation of magnetic domains. The model is used to explain the magnetic and magnetostrictive properties of Terfenol-D, including the observed negative strictions and large change in strain. The fourth chapter goes on to examine the magnetic properties of Terfenol-D along different crystallographic orientations. In the fifth chapter initial data are presented on the time dependence of magnetization in nickel.

  14. Magnetic and Magneto-Optical Properties in Paramagnetic NdF3 Under High Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; LIU Gong-Qiang

    2005-01-01

    In this paper, we first theoretically report the magnetic and magneto-optical properties in paramagnetic media under high external magnetic field. Considering the action of the external magnetic field He and indirect exchange interaction Hv, the characteristic of the magnetic saturation and the property of the Faraday rotation to be nonlinear with external magnetic field are presented in paramagnetic NdF3. In terms of our theory, the indirect exchange interaction plays an important role in the magnetization M and the Faraday rotation θ in NdF3 under high external magnetic field. The theory is in good agreement with experimental results. On the other hand, a reasonable explanation for the temperature dependence of the ratio of the Verdet constant to the magnetic susceptibility V/x is obtained.

  15. High aspect ratio tungsten grating on ultrathin Si membranes for extreme UV lithography

    Science.gov (United States)

    Peng, Xinsheng; Ying, Yulong

    2016-09-01

    Extreme ultraviolet lithography is one of the modern lithography tools for high-volume manufacturing with 22 nm resolution and beyond. But critical challenges exist to the design and fabrication of large-scale and highly efficient diffraction transmission gratings, significantly reducing the feature sizes down to 22 nm and beyond. To achieve such a grating, the surface flatness, the line edge roughness, the transmission efficiency and aspect ratio should be improved significantly. Delachat et al (2015 Nanotechnology 26 108262) develop a full process to fabricate a tungsten diffraction grating on an ultrathin silicon membrane with higher aspect ratio up to 8.75 that met all the aforementioned requirements for extreme ultraviolet lithography. This process is fully compatible with standard industrial extreme ultraviolet lithography.

  16. High aspect ratio tungsten grating on ultrathin Si membranes for extreme UV lithography.

    Science.gov (United States)

    Peng, Xinsheng; Ying, Yulong

    2016-09-02

    Extreme ultraviolet lithography is one of the modern lithography tools for high-volume manufacturing with 22 nm resolution and beyond. But critical challenges exist to the design and fabrication of large-scale and highly efficient diffraction transmission gratings, significantly reducing the feature sizes down to 22 nm and beyond. To achieve such a grating, the surface flatness, the line edge roughness, the transmission efficiency and aspect ratio should be improved significantly. Delachat et al (2015 Nanotechnology 26 108262) develop a full process to fabricate a tungsten diffraction grating on an ultrathin silicon membrane with higher aspect ratio up to 8.75 that met all the aforementioned requirements for extreme ultraviolet lithography. This process is fully compatible with standard industrial extreme ultraviolet lithography.

  17. Extremely large bandwidth and ultralow-dispersion slow light in photonic crystal waveguides with magnetically controllability

    DEFF Research Database (Denmark)

    Pu, Shengli; Wang, Haotian; Wang, Ning;

    2013-01-01

    A line-defect waveguide within a two-dimensional magnetic-fluid-based photonic crystal with 45o-rotated square lattice is presented to have excellent slow light properties. The bandwidth centered at $$ \\lambda_{0} $$ = 1,550 nm of our designed W1 waveguide is around 66 nm, which is very large tha...

  18. Probability modeling of high flow extremes in Yingluoxia watershed, the upper reaches of Heihe River basin

    Science.gov (United States)

    Li, Zhanling; Li, Zhanjie; Li, Chengcheng

    2014-05-01

    Probability modeling of hydrological extremes is one of the major research areas in hydrological science. Most basins in humid and semi-humid south and east of China are concerned for probability modeling analysis of high flow extremes. While, for the inland river basin which occupies about 35% of the country area, there is a limited presence of such studies partly due to the limited data availability and a relatively low mean annual flow. The objective of this study is to carry out probability modeling of high flow extremes in the upper reach of Heihe River basin, the second largest inland river basin in China, by using the peak over threshold (POT) method and Generalized Pareto Distribution (GPD), in which the selection of threshold and inherent assumptions for POT series are elaborated in details. For comparison, other widely used probability distributions including generalized extreme value (GEV), Lognormal, Log-logistic and Gamma are employed as well. Maximum likelihood estimate is used for parameter estimations. Daily flow data at Yingluoxia station from 1978 to 2008 are used. Results show that, synthesizing the approaches of mean excess plot, stability features of model parameters, return level plot and the inherent independence assumption of POT series, an optimum threshold of 340m3/s is finally determined for high flow extremes in Yingluoxia watershed. The resulting POT series is proved to be stationary and independent based on Mann-Kendall test, Pettitt test and autocorrelation test. In terms of Kolmogorov-Smirnov test, Anderson-Darling test and several graphical diagnostics such as quantile and cumulative density function plots, GPD provides the best fit to high flow extremes in the study area. The estimated high flows for long return periods demonstrate that, as the return period increasing, the return level estimates are probably more uncertain. The frequency of high flow extremes exhibits a very slight but not significant decreasing trend from 1978 to

  19. A genome-wide analysis of putative functional and exonic variation associated with extremely high intelligence.

    Science.gov (United States)

    Spain, S L; Pedroso, I; Kadeva, N; Miller, M B; Iacono, W G; McGue, M; Stergiakouli, E; Smith, G D; Putallaz, M; Lubinski, D; Meaburn, E L; Plomin, R; Simpson, M A

    2016-08-01

    Although individual differences in intelligence (general cognitive ability) are highly heritable, molecular genetic analyses to date have had limited success in identifying specific loci responsible for its heritability. This study is the first to investigate exome variation in individuals of extremely high intelligence. Under the quantitative genetic model, sampling from the high extreme of the distribution should provide increased power to detect associations. We therefore performed a case-control association analysis with 1409 individuals drawn from the top 0.0003 (IQ >170) of the population distribution of intelligence and 3253 unselected population-based controls. Our analysis focused on putative functional exonic variants assayed on the Illumina HumanExome BeadChip. We did not observe any individual protein-altering variants that are reproducibly associated with extremely high intelligence and within the entire distribution of intelligence. Moreover, no significant associations were found for multiple rare alleles within individual genes. However, analyses using genome-wide similarity between unrelated individuals (genome-wide complex trait analysis) indicate that the genotyped functional protein-altering variation yields a heritability estimate of 17.4% (s.e. 1.7%) based on a liability model. In addition, investigation of nominally significant associations revealed fewer rare alleles associated with extremely high intelligence than would be expected under the null hypothesis. This observation is consistent with the hypothesis that rare functional alleles are more frequently detrimental than beneficial to intelligence.

  20. Cryocooler applications for high-temperature superconductor magnetic bearings.

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, R. C.

    1998-05-22

    The efficiency and stability of rotational magnetic suspension systems are enhanced by the use of high-temperature superconductor (HTS) magnetic bearings. Fundamental aspects of the HTS magnetic bearings and rotational magnetic suspension are presented. HTS cooling can be by liquid cryogen bath immersion or by direct conduction, and thus there are various applications and integration issues for cryocoolers. Among the numerous cryocooler aspects to be considered are installation; operating temperature; losses; and vacuum pumping.

  1. Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs

    CERN Document Server

    Mukhopadhyay, Banibrata

    2016-01-01

    We explore the possibility that soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are powered by highly magnetized white dwarfs (B-WDs). We take a sample of SGRs and AXPs and provide the possible parameter space in mass, radius, and surface magnetic field based on their observed properties (period and its derivative) and the assumption that these sources obey the mass-radius relation derived for the B-WDs. The radius and magnetic field of B-WDs are adequate to explain energies in SGRs/AXPs as the rotationally powered energy. In addition, B-WDs also adequately explain the perplexing radio transient GCRT J1745-3009 as a white dwarf pulsar. Note that the radius and magnetic fields of B-WDs are neither extreme (unlike of highly magnetized neutron stars) nor ordinary (unlike of magnetized white dwarfs, yet following the Chandrasekhar's mass-radius relation (C-WDs)). In order to explain SGRs/AXPs, while the highly magnetized neutron stars require an extra, observationally not well established yet, ...

  2. Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs

    Science.gov (United States)

    Mukhopadhyay, Banibrata; Rao, A. R.

    2016-05-01

    We explore the possibility that soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are powered by highly magnetized white dwarfs (B-WDs). We take a sample of SGRs and AXPs and provide the possible parameter space in mass, radius, and surface magnetic field based on their observed properties (period and its derivative) and the assumption that these sources obey the mass-radius relation derived for the B-WDs. The radius and magnetic field of B-WDs are adequate to explain energies in SGRs/AXPs as the rotationally powered energy. In addition, B-WDs also adequately explain the perplexing radio transient GCRT J1745-3009 as a white dwarf pulsar. Note that the radius and magnetic fields of B-WDs are neither extreme (unlike of highly magnetized neutron stars) nor ordinary (unlike of magnetized white dwarfs, yet following the Chandrasekhar's mass-radius relation (C-WDs)). In order to explain SGRs/AXPs, while the highly magnetized neutron stars require an extra, observationally not well established yet, source of energy, the C-WDs predict large ultra-violet luminosity which is observationally constrained from a strict upper limit. Finally, we provide a set of basic differences between the magnetar and B-WD hypotheses for SGRs/AXPs.

  3. High-resolution analysis of 1 day extreme precipitation in Sicily

    Science.gov (United States)

    Maugeri, M.; Brunetti, M.; Garzoglio, M.; Simolo, C.

    2015-04-01

    Sicily, the major Mediterranean island, experienced several exceptional precipitation episodes and floods during the last century, with dramatic consequences on human life and environment. A long term, rational planning of urban development is mandatory for protecting population and avoiding huge economic losses in the future. This requires a deep knowledge of the distributional features of extreme precipitation over the complex territory of Sicily. In the present study, we address this issue, and attempt a detailed investigation of observed 1-day precipitation extremes and their frequency distribution, based on a dense data-set of high-quality, homogenized station records in 1921-2005. We extrapolate very high quantiles (return levels) corresponding to 10-, 50- and 100-year return periods, as predicted by a generalized extreme value distribution. Return level estimates are produced on a regular high-resolution grid (30 arcsec) using a variant of regional frequency analysis combined with regression techniques. Results clearly reflect the complexity of this region, and make evident the high vulnerability of its eastern and northeastern parts as those prone to the most intense and potentially damaging events. This analysis thus provides an operational tool for extreme precipitation risk assessment and, at the same time, is an useful basis for validation and downscaling of regional climate models.

  4. Complex Systems Theory to understand extremely low frequency magnetic fields interaction with immune cells

    Science.gov (United States)

    Vázquez-Coutiño, G. A.; Serrano-Luna, G.; Cañedo-Dorantes, L.; Godina-Nava, J. J.; Rodríguez-Segura, M. A.

    2003-09-01

    Well-documented studies about the interaction of extremely low frequency electromagnetic fields (ELF) with lymphocytes provide elements for the development of non-linear theoretical models. The Eichwald-Kaiser model of calcium oscillations was tested with a rectified cosine function at a frequency of 120 Hz. A change in dynamical behavior of calcium oscillations, from periodic in the normal case (without perturbation, what corresponds to a limit cycle) to the existence of very small micro-oscillations and a strange attractor in the perturbed case was found. It is concluded that the ELF configuration used in this model, alters the dynamical behavior of calcium oscillations in lymphocytes.

  5. Effects of extremely low frequency magnetic fields on gap junctional intercellular communication and its mechanism

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The study on biological effect of electromagnetic fields has been paid close attention in recent years. Gap junctional intercellular communication (GJIC) plays an important role in the maintenance of cell proliferation and differentiation, and in the multistage process of carcinogenesis. A series of researches showed that xtremely low frequency (ELF) magnetic fields not only enhance the inhibition of GJIC induced by 12-O-tetradecanoylphorbol-13-acetate, but also inhibit GJIC directly when the intensity is equal to or more than 0.4  mT, and that the mechanisms of GJIC inhibition by ELF magnetic fields are due to hyperphosphorylation of connexin 43, which is mediated by protein kinase C-activated signal transduction, and the internalization of connexin 43 from plasma membrane to cytoplasm.

  6. Optical Signatures from Magnetic 2-D Electron Gases in High Magnetic Fields to 60 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Crooker, S.A.; Kikkawa, J.M.; Awschalom, D.D.; Smorchikova, I.P.; Samarth, N.

    1998-11-08

    We present experiments in the 60 Tesla Long-Pulse magnet at the Los Alamos National High Magnetic Field Lab (NHMFL) focusing on the high-field, low temperature photoluminescence (PL) from modulation-doped ZnSe/Zn(Cd,Mn)Se single quantum wells. High-speed charge-coupled array detectors and the long (2 second) duration of the magnet pulse permit continuous acquisition of optical spectra throughout a single magnet shot. High-field PL studies of the magnetic 2D electron gases at temperatures down to 350mK reveal clear intensity oscillations corresponding to integer quantum Hall filling factors, from which we determine the density of the electron gas. At very high magnetic fields, steps in the PL energy are observed which correspond to the partial unlocking of antiferromagnetically bound pairs of Mn2+ spins.

  7. Magnetization of High Density Hadronic Fluid

    DEFF Research Database (Denmark)

    Bohr, Henrik; Providencia, Constanca; da Providencia, João

    2012-01-01

    of the magnetization is derived by first considering and solving the Dirac equation of a fermion in interaction with a magnetic field and with a chiral sigma-pion pair. The solution provides the energies of single-particle states. The energy of the system is found by summing up contributions from all particles...

  8. High Field Magnetization of Tb Single Crystals

    DEFF Research Database (Denmark)

    Roeland, L. W.; Cock, G. J.; Lindgård, Per-Anker

    1975-01-01

    The magnetization of Tb single crystals was measured in magnetic fields to 34T along the hard direction at temperature of 1.8, 4.2, 65.5 and 77K, and along with easy direction at 4.2 and 77K. The data are compared with the results of a self-consistent spin wave calculation using a phenomenological...

  9. Particle flocculation and filtration by high-gradient magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Tsouris, C. [Oak Ridge National Lab., TN (United States); Yiacoumi, S. [Georgie Inst. of Technology, Atlanta, GA (United States)

    1997-01-01

    Flocculation and filtration of micrometer-sized particles in a high-gradient magnetic field (HGMF) were investigated. Experiments were conducted using a cryogenic magnet of 6 Tesla maximum strength. Hematite particles were used for flocculation and filtration experiments. A new approach of using magnetic fields to enhance separation of weakly magnetic particles was also investigated. This approach is based on magnetic seeding which involves flocculation of existing non-magnetic particles with injected paramagnetic particles. A particle-flocculation model was developed based on trajectory analysis. External forces due to gravity and magnetism, and interparticle forces such as electrostatic, hydrodynamic, magnetic dipole, and van der Waals forces, were taken into consideration in these models.

  10. Torsional oscillations of neutron stars with highly tangled magnetic fields

    CERN Document Server

    Sotani, Hajime

    2015-01-01

    To determine the frequencies of magnetic oscillations in the neutron stars with highly tangled magnetic fields, we derive the perturbation equations. We assume that the field strength of the global magnetic structure is so small that such fields are negligible compared with the tangled fields, which may still be far from a realistic configuration. Then, we systematically examine the spectra of the magnetic oscillations, as varying the magnetic field strength and stellar mass. The frequencies without crust elasticity are completely proportional to the strength of magnetic field, whose proportionality constant depends strongly on the stellar mass. On the other hand, the oscillation spectra with crust elasticity become more complicated, where the frequencies even for weak magnetic fields are different from the crustal torsional oscillations without magnetic fields. For discussing the spectra, the critical field strength can play an important role, which is determined in such a way that the shear velocity is equi...

  11. Extreme deformations and clusterization at high spin in the A ~ 40 mass region

    Science.gov (United States)

    Ray, Debisree; Afanasjev, Anatoli

    2015-10-01

    Recent revival of the interest to the study of superdeformation and clusterization in light nuclei has motivated us to undertake the study of extreme deformations in the A ~ 32 - 50 N ~ Z nuclei. Unfortunately, at spin zero the predicted structures with extreme deformation are located at high excitation energies which prevents their experimental observation. On the other hand, the rotation brings such structures closer to the yrast line and, in principle, makes their observation possible with future generation of facilities such as GRETA. Thus, the systematic study of the extremely deformed structures and clusterization has been performed in the framework of cranked relativistic mean field theory. The major features of such structures, the spins at which they become yrast and the possiblities of their experimental observation will be discussed in this presentation. This work has been supported by the U.S. Department of Energy under the Grant DE-FG02-07ER41459.

  12. Applications of high dielectric materials in high field magnetic resonance

    Science.gov (United States)

    Haines, Kristina Noel

    At high magnetic fields, radiation losses, wavelength effects, self-resonance, and the high resistance of components all contribute to losses in conventional RF MRI coil designs. The hypothesis tested here is that these problems can be combated by the use of high permittivity ceramic materials at high fields. High permittivity ceramic dielectric resonators create strong uniform magnetic fields in compact structures at high frequencies and can potentially solve some of the challenges of high field coil design. In this study NMR probes were constructed for operation at 600 MHz (14.1 Tesla) and 900 MHz (21.1 Tesla) using inductively fed CaTiO3 (relative permittivity of 156-166) cylindrical hollow bore dielectric resonators. The designs showed the electric field is largely confined to the dielectric itself, with near zero values in the hollow bore, which accommodates the sample. The 600 MHz probe has an unmatched Q value greater than 2000. Experimental and simulation mapping of the RF field show good agreement, with the ceramic resonator giving a pulse width approximately 25% less than a loop gap resonator of similar inner dimensions. High resolution images, with voxel dimensions less than 50 microm3, have been acquired from fixed zebrafish samples, showing excellent delineation of several fine structures. The 900 MHz probe has an unmatched Q value of 940 and shows Q performance five times better than Alderman-Grant and loop-gap resonators of similar dimensions. High resolution images were acquired of an excised mouse spinal cord (25 microm 3) and an excised rat soleus muscle (20 microm3). The spatial distribution of electromagnetic fields within the human body can be tailored using external dielectric materials. Here, a new material is introduced with high dielectric constant and low background MRI signal. The material is based upon metal titanates, which can be made into geometrically formable suspensions in de-ionized water. The suspension's material properties are

  13. 极低频磁场与癌症%Extremely low-frequency magnetic fields and cancers

    Institute of Scientific and Technical Information of China (English)

    王学斌; 刘凤莲

    2007-01-01

    OBJECTIVE: All the people in modern world are exposed to the industrial frequency magnetism (extremeiy low-frequency magnetic fields, ELFMF). There are important academic and practical significance to understand the influence of ELFMF on human diseases.DATA SOURCES: A computer-based online search was conducted in HighWire database for English literatures about the relation between ELFMF and human cancers from January 1991 to March 2006 by using the key words of "extremely low frequency magnetic fields, cancer".STUDY SELECTION: All the collected literatures were screened. Inclusion criteria: ① To browse the abstracts of the literatures to examine primitively, and select the articles experimented with the cytological, molecular biological and epidemiological methods. ② Choosing the separate articles by studying with different animals but having got the same results.③ Comparing and analyzing the original and reviewed articles about the relations between ELFMF and cancers.DATA EXTRACTION: A total 90 original and 4 reviewed literatures about ELFMF and cancers were collected and 29 and 4 papers were accordance with the criteria, respectively. In the 47 eliminated articles, 32 of them were unrelated or repetitive to our topic, 5 of them were published earlier or the conclusions were ambiguous, and other 10 of them used only the epidemiological methods.DATA SYNTHESIS : ① For a long time, the question whether 50/60 Hz ELFMF has the carcinogenic effects has been disputed in epidemiology and cytology. ② Majority statistical results in epidemiology showed that the crowds exposed to ELFMF for long or frequent time had an higher ratios suffering cancers than the normal, thereinto, the dangerousness such as leucocythemia, brain cancer and breast cancer is especially high. ③ However, the observation in cytology indicated that the normal cultural cells exposed to ELFMF had not increased the cell divisions or appeared cancer signals, and even in some reports, ELFMF may

  14. Reducing Magnetic Noise of an Unmanned Aerial Vehicle for High-Quality Magnetic Surveys

    Directory of Open Access Journals (Sweden)

    Boris Sterligov

    2016-01-01

    Full Text Available The use of light and ultralight unmanned aerial vehicles (UAVs for magnetic data acquisition can be efficient for resolving multiple geological and engineering tasks including geological mapping, ore deposits’ prospecting, and pipelines’ monitoring. The accuracy of the aeromagnetic data acquired using UAV depends mainly on deviation noise of electric devices (engine, servos, etc.. The goal of this research is to develop a nonmagnetic unmanned aerial platform (NUAP for high-quality magnetic surveys. Considering parameters of regional and local magnetic survey, a fixed-wing UAV suits geological tasks better for plain area and copter type for hills and mountains. Analysis of the experimental magnetic anomalies produced by a serial light fixed-wing UAV and subsequent magnetic and aerodynamic modeling demonstrates a capacity of NUAP with internal combustion engine carrying an atomic magnetic sensor mounted on the UAV wings to facilitate a high-quality magnetic survey.

  15. Influence of High Harmonics of Magnetic Fields on Trapped Magnetic Fluxes in HTS Bulk

    Science.gov (United States)

    Yamagishi, K.; Miyagi, D.; Tsukamoto, O.

    Various kinds of HTS bulk motors are proposed and have been developed. Generally, those motors are driven by semiconductor inverters and currents fed to the armature windings contain high harmonics. Therefore, the bulks are exposed to high harmonics magnetic fields and AC losses are produced in the bulks. The AC losses deteriorate the efficiency of the motors and cause temperature rise of the bulks which decrease the trapped magnetic fluxes of the bulks. Usually, electro-magnetic shielding devices are inserted between the bulks and armature windings. However, the shielding devices degrade compactness of the motors. Therefore, it is important to have knowledge of the influence of the high harmonics magnetic fields on the AC losses and trapped magnetic fluxes of the bulk for optimum design of the shielding devices. In this work, the authors experimentally study the influence of high harmonics magnetic fields.

  16. Characteristics of Magnetic Tribology on High Flux Pair of Magnetic Driving Mechanism

    Institute of Scientific and Technical Information of China (English)

    ZHOUQiang; XURui-qing; XUHong-qiu

    2004-01-01

    The rectangle-like pulsed magnetic field acted on the rubbing pair was presents through analyzing the exciting property in the reciprocationg travel the test of wear in NG-x tester shows that the wear between the electromagnetic core and down magnetic board distributes in the high veloctity slip region of reciprocating travel,an the adhesive wear in the low velocity slip region nearby up and down dead points is depressed owing to the presence of high flux magnetic field.the lubrication by magnetic fluid with high permeability effectively reduces the friction and wear of high flux rubbing pair and mproves the conductiong property of magnetic circuit constructed by the rubbing pair which is beneficial to increase the operation performance of magnetic driving mechanism.

  17. Extremely high thermal conductivity anisotropy of double-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Zhaoji Ma

    2017-06-01

    Full Text Available Based on molecular dynamics simulations, we reveal that double-walled carbon nanotubes can possess an extremely high anisotropy ratio of radial to axial thermal conductivities. The mechanism is basically the same as that for the high thermal conductivity anisotropy of graphene layers - the in-plane strong sp2 bonds lead to a very high intralayer thermal conductivity while the weak van der Waals interactions to a very low interlayer thermal conductivity. However, different from flat graphene layers, the tubular structures of carbon nanotubes result in a diameter dependent thermal conductivity. The smaller the diameter, the larger the axial thermal conductivity but the smaller the radial thermal conductivity. As a result, a DWCNT with a small diameter may have an anisotropy ratio of thermal conductivity significantly higher than that for graphene layers. The extremely high thermal conductivity anisotropy allows DWCNTs to be a promising candidate for thermal management materials.

  18. Extremely high thermal conductivity anisotropy of double-walled carbon nanotubes

    Science.gov (United States)

    Ma, Zhaoji; Guo, Zhengrong; Zhang, Hongwei; Chang, Tienchong

    2017-06-01

    Based on molecular dynamics simulations, we reveal that double-walled carbon nanotubes can possess an extremely high anisotropy ratio of radial to axial thermal conductivities. The mechanism is basically the same as that for the high thermal conductivity anisotropy of graphene layers - the in-plane strong sp2 bonds lead to a very high intralayer thermal conductivity while the weak van der Waals interactions to a very low interlayer thermal conductivity. However, different from flat graphene layers, the tubular structures of carbon nanotubes result in a diameter dependent thermal conductivity. The smaller the diameter, the larger the axial thermal conductivity but the smaller the radial thermal conductivity. As a result, a DWCNT with a small diameter may have an anisotropy ratio of thermal conductivity significantly higher than that for graphene layers. The extremely high thermal conductivity anisotropy allows DWCNTs to be a promising candidate for thermal management materials.

  19. Spontaneous radiation emission from short, high field strength magnetic devices

    Directory of Open Access Journals (Sweden)

    G. A. Krafft

    2006-01-01

    Full Text Available Since the earliest papers on undulators were published, it has been known how to calculate the spontaneous emission spectrum from short undulators when the magnetic field strength parameter is small compared to unity, or in “single” frequency sinusoidal undulators where the magnetic field strength parameter is comparable to or larger than unity, but where the magnetic field amplitude is constant throughout the undulator. Fewer general results have been obtained in the case where the magnetic device is both short, i.e., the magnetic field strength parameter changes appreciably throughout the device, and the magnetic field strength is high enough that ponderomotive effects, radiation retardation, and harmonic generation are important physical phenomena. In this paper a general method is presented for calculating the radiation spectrum for short, high-field magnetic devices. It is used to calculate the emission from some designs of recent interest.

  20. High temperature superconductivity induced by incipient magnetism

    Science.gov (United States)

    Weger, M.; Pereg, Y.

    1990-10-01

    We consider the BCS gap equation, with an attractive interaction λ with an upper cutoff ω 0 and lower cutoff ω 1, and a repulsive interaction μ with cutoffΓ. We consider parameters such that a superconducting solution does not exist. We add a repulsive interaction ν eith cutoff ω1 ( ω1 < ω0), and show that this repulsive interaction (that we attribute to incipient magnetism) induces a superconducting state possessing a high transition temperature. In this state, the gap function Δ(ɛ) oscillates as function of ɛ, with a period of order ω 0. We also find solutions antisymmetric in energy [ Δ( ɛ) = - Δ(- ɛ) ], which turn out to be almost degenerate with the normal, symmetric ones. We discuss the physical implications of this model. Our model thus combines a low frequency repulsion due to antiferromagnetic interactions, with excitonic attraction at intermediate frequencies, and ordinary Coulomb repulsion above that. All frequency ranges, and coupling strengths, are comparable with the bandwidth.

  1. High spin rate magnetic controller for nanosatellites

    Science.gov (United States)

    Slavinskis, A.; Kvell, U.; Kulu, E.; Sünter, I.; Kuuste, H.; Lätt, S.; Voormansik, K.; Noorma, M.

    2014-02-01

    This paper presents a study of a high rate closed-loop spin controller that uses only electromagnetic coils as actuators. The controller is able to perform spin rate control and simultaneously align the spin axis with the Earth's inertial reference frame. It is implemented, optimised and simulated for a 1-unit CubeSat ESTCube-1 to fulfil its mission requirements: spin the satellite up to 360 deg s-1 around the z-axis and align its spin axis with the Earth's polar axis with a pointing error of less than 3°. The attitude of the satellite is determined using a magnetic field vector, a Sun vector and angular velocity. It is estimated using an Unscented Kalman Filter and controlled using three electromagnetic coils. The algorithm is tested in a simulation environment that includes models of space environment and environmental disturbances, sensor and actuator emulation, attitude estimation, and a model to simulate the time delay caused by on-board calculations. In addition to the normal operation mode, analyses of reduced satellite functionality are performed: significant errors of attitude estimation due to non-operational Sun sensors; and limited actuator functionality due to two non-operational coils. A hardware-in-the-loop test is also performed to verify on-board software.

  2. High-Field Superconducting Magnets Supporting PTOLEMY

    Science.gov (United States)

    Hopkins, Ann; Luo, Audrey; Osherson, Benjamin; Gentile, Charles; Tully, Chris; Cohen, Adam

    2013-10-01

    The Princeton Tritium Observatory for Light, Early Universe, Massive Neutrino Yield (PTOLEMY) is an experiment planned to collect data on Big Bang relic neutrinos, which are predicted to be amongst the oldest and smallest particles in the universe. Currently, a proof-of-principle prototype is being developed at Princeton Plasma Physics Laboratory to test key technologies associated with the experiment. A prominent technology in the experiment is the Magnetic Adiabatic Collimation with an Electrostatic Filter (MAC-E filter), which guides tritium betas along magnetic field lines generated by superconducting magnets while deflecting those of lower energies. B field mapping is performed to ensure the magnets produce a minimum field at the midpoint of the configuration of the magnets and to verify accuracy of existing models. Preliminary tests indicate the required rapid decrease in B field strength from the bore of the more powerful 3.35 T magnet, with the field dropping to 0.18 T approximately 0.5 feet from the outermost surface of the magnet.

  3. Magnetic Moment and Spin of the Extremely Proton-Rich Nucleus {sup 23}Al

    Energy Technology Data Exchange (ETDEWEB)

    Matsuta, K., E-mail: matsuta@vg.phys.sci.osaka-u.ac.jp; Nakashima, Y.; Nagatomo, T.; Mihara, M.; Kumashiro, S.; Fujiwara, H.; Ogura, M.; Fukuda, M.; Minamisono, T. [Osaka University, Department of Physics (Japan); Sumikama, T. [RIKEN (Japan); Ozawa, A. [University of Tsukuba, Institute of Physics (Japan); Yamada, K. [Rikkyo University, College of Science (Japan); Momota, S.; Nojiri, Y. [Tosayamada, Kochi University of Technology (Japan); Ota, M.; Ohtsubo, T.; Izumikawa, T. [Niigata University, Department of Physics (Japan); Yoshida, K. [RIKEN (Japan); Minamisono, K. [TRIUMF (Canada); Suzuki, T. [Saitama University, Department of Physics (Japan)

    2004-12-15

    The g-factor of the exteremely proton-rich nucleus {sup 23}Al(T{sub 1/2} 0.47 s) has been measured for the first time, applying {beta}-NMR technique on this nucleus implanted in Si. The obtained vertical bar g vertical bar (1.58 {+-} 0.2) suggests that the spin of the ground state of {sup 23}Al is 5 / 2. The magnetic moment is determined as vertical bar {mu} vertical bar (3.95 {+-} 0.55) {mu}{sub N}.

  4. Navigated Transcranial Magnetic Stimulation: A Biologically Based Assay of Lower Extremity Impairment and Gait Velocity

    Science.gov (United States)

    Dunning, Kari; Ying, Jun; Laine, Jarmo; Page, Stephen J.

    2017-01-01

    Objectives. (a) To determine associations among motor evoked potential (MEP) amplitude, MEP latency, lower extremity (LE) impairment, and gait velocity and (b) determine the association between the presence of a detectable MEP signal with LE impairment and with gait velocity. Method. 35 subjects with chronic, stable LE hemiparesis were undergone TMS, the LE section of the Fugl-Meyer Impairment Scale (LE FM), and 10-meter walk test. We recorded presence, amplitude, and latency of MEPs in the affected tibialis anterior (TA) and soleus (SO). Results. MEP presence was associated with higher LEFM scores in both the TA and SO. MEP latency was larger in subjects with lower LEFM and difficulty walking. Conclusion. MEP latency appears to be an indicator of LE impairment and gait. Significance. Our results support the precept of using TMS, particularly MEP latency, as an adjunctive LE outcome measurement and prognostic technique. PMID:28243474

  5. High temperature superconductor cable concepts for fusion magnets

    CERN Document Server

    AUTHOR|(CDS)2078397

    2013-01-01

    Three concepts of high temperature superconductor cables carrying kA currents (RACC, CORC and TSTC) are investigated, optimized and evaluated in the scope of their applicability as conductor in fusion magnets. The magnetic field and temperature dependence of the cables is measured; the thermal expansion and conductivity of structure, insulation and filling materials are investigated. High temperature superconductor winding packs for fusion magnets are calculated and compared with corresponding low temperature superconductor cases.

  6. Review- Numerical simulation of chainlike cluster movement of feeble magnetic particles by induced magnetic dipole moment under high magnetic fields

    Directory of Open Access Journals (Sweden)

    Tsutomu Ando, Noriyuki Hirota and Hitoshi Wada

    2009-01-01

    Full Text Available In this paper, the motion of a chainlike cluster of feeble magnetic particles induced by high magnetic field is discussed on the basis of the results of numerical simulations. The simulations were performed on glass particles with a diameter of 0.8 mm; and the viscosity, applied magnetic field and magnetic properties of the surrounding medium were changed. In addition to the magnetic field and the difference in magnetic susceptibility between the particles and the surrounding medium, the obtained results indicate that the viscosity is an essential factor for the formation of the chainlike alignment of feeble magnetic particles. We also carried out simulations using glass particles with a smaller diameter of 0.1 mm. Chainlike clusters were produced similar to those of ferromagnetic particles formed in a ferromagnetic fluid.

  7. Role of magnetic resonance imaging in entrapment and compressive neuropathy - what, where, and how to see the peripheral nerves on the musculoskeletal magnetic resonance image: part 1. Overview and lower extremity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sungjun [Yonsei University, Department of Diagnostic Radiology, College of Medicine, Seoul (Korea); Hanyang University, Kuri Hospital, Department of Diagnostic Radiology, College of Medicine, Kuri City, Kyunggi-do (Korea); Choi, Jin-Young; Huh, Yong-Min; Song, Ho-Taek; Lee, Sung-Ah [Yonsei University, Department of Diagnostic Radiology, College of Medicine, Seoul (Korea); Kim, Seung Min [Yonsei University, Department of Neurology, College of Medicine, Seoul (Korea); Suh, Jin-Suck [Yonsei University, Department of Diagnostic Radiology, College of Medicine, Seoul (Korea); Yonsei University, Research Institute of Radiological Science, College of Medicine, Seoul (Korea)

    2007-01-15

    The diagnosis of nerve entrapment and compressive neuropathy has been traditionally based on the clinical and electrodiagnostic examinations. As a result of improvements in the magnetic resonance (MR) imaging modality, it plays not only a fundamental role in the detection of space-occupying lesions but also a compensatory role in clinically and electrodiagnostically inconclusive cases. Although ultrasound has undergone further development in the past decades and shows high resolution capabilities, it has inherent limitations due to its operator dependency. We review the general concepts that should be known to evaluate the entrapment and compressive neuropathy in MR imaging. We also review the course of normal peripheral nerves, as well as various clinical demonstrations and pathological features of compressed and entrapped nerves in the lower extremities on MR imaging, according to the nerves involved. The common sites of nerve entrapment of the lower extremity are as follows: sciatic nerve around the piriformis muscle; tibial nerve at the popliteal fossa and tarsal tunnel, common peroneal nerve around the fibular neck, and digital nerve near the metatarsal head. Although MR imaging can depict the peripheral nerves in the extremities effectively, radiologists should be familiar with nerve pathways, common sites of nerve compression, and common space-occupying lesions resulting in nerve compression in MR imaging. (orig.)

  8. Role of magnetic resonance imaging in entrapment and compressive neuropathy - what, where, and how to see the peripheral nerves on the musculoskeletal magnetic resonance image: Part 2. Upper extremity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sungjun [Yonsei University, Department of Diagnostic Radiology, College of Medicine, Seoul (Korea); Hanyang University, Kuri Hospital, Department of Diagnostic Radiology, College of Medicine, Kuri City, Kyunggi-do (Korea); Choi, Jin-Young; Huh, Yong-Min; Song, Ho-Taek; Lee, Sung-Ah [Yonsei University, Department of Diagnostic Radiology, College of Medicine, Seoul (Korea); Kim, Seung Min [Yonsei University, Department of Neurology, College of Medicine, Seoul (Korea); Suh, Jin-Suck [Yonsei University, Department of Diagnostic Radiology, College of Medicine, Seoul (Korea); Yonsei University, Research Institute of Radiological Science, College of Medicine, Seoul (Korea)

    2007-02-15

    The diagnosis of nerve entrapment and compressive neuropathy has been traditionally based on the clinical and electrodiagnostic examinations. As a result of improvements in the magnetic resonance (MR) imaging modality, it plays not only a fundamental role in the detection of space-occupying lesions, but also a compensatory role in clinically and electrodiagnostically inconclusive cases. Although ultrasound has undergone further development in the past decades and shows high resolution capabilities, it has inherent limitations due to its operator dependency. We review the course of normal peripheral nerves, as well as various clinical demonstrations and pathological features of compressed and entrapped nerves in the upper extremities on MR imaging, according to the nerves involved. The common sites of nerve entrapment of the upper extremity are as follows: the brachial plexus of the thoracic outlet; axillary nerve of the quadrilateral space; radial nerve of the radial tunnel; ulnar nerve of the cubital tunnel and Guyon's canal; median nerve of the pronator syndrome, anterior interosseous nerve syndrome, and carpal tunnel syndrome. Although MR imaging can depict the peripheral nerves in the extremities effectively, radiologists should be familiar with nerve pathways, common sites of nerve compression, and common space-occupying lesions resulting in nerve compression in MR imaging. (orig.)

  9. Cryocooled superconducting magnets for high magnetic fields at the HFLSM and future collaboration with the TML

    Science.gov (United States)

    Watanabe, K.; Nishijima, G.; Awaji, S.; Koyama, K.; Takahashi, K.; Kobayashi, N.; Kiyoshi, T.

    2006-11-01

    A hybrid magnet needs a large amount of liquid helium for operation. In order to make an easy-to-operate hybrid magnet system, we constructed a cryocooled 28 T hybrid magnet, consisting of an outer cryocooled 10 T superconducting magnet and an inner traditional water-cooled 19 T resistive magnet. As a performance test, the cryocooled hybrid magnet generated 27.5 T in a 32 mm room temperature experimental bore. As long as Nb3Sn superconducting wires are employed, the expected maximum high field generation in the cryocooled superconducting magnet will be 17 T at 5 K. We adopted the high temperature superconducting insert coil, employing Ag-sheathed Bi2Sr2Ca2Cu3O10superconducting tape. In combination with the low temperature 16.5 T back-up coil with a 174 mm cold bore, the cryocooled high temperature superconducting magnet successfully generated the total central field of 18.1 T in a 52 mm room temperature bore. As a next step, we start the collaboration with the National Institute for Materials Science for the new developmental works of a 30 T high temperature superconducting magnet and a 50 T-class hybrid magnet.

  10. Solar cosmic rays during the extremely high ground level enhancement on 23 February 1956

    Directory of Open Access Journals (Sweden)

    A. Belov

    2005-09-01

    Full Text Available The 23 February 1956 ground level enhancement of the solar cosmic ray intensity (GLE05 is the most famous among the proton events observed since 1942. But we do not have a great deal of information on this event due to the absence of solar wind and interplanetary magnetic field measurements at that time. Furthermore, there were no X-Ray or gamma observations and the information on the associated flare is limited. Cosmic ray data was obtained exclusively by ground level detectors of small size and in some cases of a non-standard design. In the present work all available data from neutron monitors operating in 1956 were analyzed, in order to develop a model of the solar cosmic ray behavior during the event. The time-dependent characteristics of the cosmic ray energy spectrum, cosmic ray anisotropy, and differential and integral fluxes have been evaluated utilizing different isotropic and anisotropic models. It is shown that the most outstanding features of this proton enhancement were a narrow and extremely intense beam of ultra-relativistic particles arriving at Earth just after the onset and the unusually high maximum solar particle energy. However, the contribution of this beam to the overall solar particle density and fluency was not significant because of its very short duration and small width. Our estimate of the integral flux for particles with energies over 100 MeV places this event above all subsequent. Perhaps the number of accelerated low energy particles was closer to a record value, but these particles passed mainly to the west of Earth.

    Many features of this GLE are apparently explained by the peculiarity of the particle interplanetary propagation from a remote (near the limb source. The quality of the available neutron monitor data does not allow us to be certain of some details; these may be cleared up by the incorporation into the analysis of data from muonic telescopes and ionization chambers

  11. Kerr/CFT correspondence in a 4D extremal rotating regular black hole with a non-linear magnetic monopole

    Directory of Open Access Journals (Sweden)

    Shingo Takeuchi

    2017-08-01

    Full Text Available We carry out the Kerr/CFT correspondence in a four-dimensional extremal rotating regular black hole with a non-linear magnetic monopole (NLMM. One problem in this study would be whether our geometry can be a solution or not. We search for the way making our rotating geometry into a solution based on the fact that the Schwarzschild regular geometry can be a solution. However, in the attempt to extend the Schwarzschild case that we can naturally consider, it turns out that it is impossible to construct a model in which our geometry can be a exact solution. We manage this problem by making use of the fact that our geometry can be a solution approximately in the whole space-time except for the black hole's core region. As a next problem, it turns out that the equation to obtain the horizon radii is given by a fifth-order equation due to the regularization effect. We overcome this problem by treating the regularization effect perturbatively. As a result, we can obtain the near-horizon extremal Kerr (NHEK geometry with the correction of the regularization effect. Once obtaining the NHEK geometry, we can obtain the central charge and the Frolov–Thorne temperature in the dual CFT. Using these, we compute its entropy through the Cardy formula, which agrees with the one computed from the Bekenstein–Hawking entropy.

  12. Detection and Attribution of Simulated Climatic Extreme Events and Impacts: High Sensitivity to Bias Correction

    Science.gov (United States)

    Sippel, S.; Otto, F. E. L.; Forkel, M.; Allen, M. R.; Guillod, B. P.; Heimann, M.; Reichstein, M.; Seneviratne, S. I.; Kirsten, T.; Mahecha, M. D.

    2015-12-01

    Understanding, quantifying and attributing the impacts of climatic extreme events and variability is crucial for societal adaptation in a changing climate. However, climate model simulations generated for this purpose typically exhibit pronounced biases in their output that hinders any straightforward assessment of impacts. To overcome this issue, various bias correction strategies are routinely used to alleviate climate model deficiencies most of which have been criticized for physical inconsistency and the non-preservation of the multivariate correlation structure. We assess how biases and their correction affect the quantification and attribution of simulated extremes and variability in i) climatological variables and ii) impacts on ecosystem functioning as simulated by a terrestrial biosphere model. Our study demonstrates that assessments of simulated climatic extreme events and impacts in the terrestrial biosphere are highly sensitive to bias correction schemes with major implications for the detection and attribution of these events. We introduce a novel ensemble-based resampling scheme based on a large regional climate model ensemble generated by the distributed weather@home setup[1], which fully preserves the physical consistency and multivariate correlation structure of the model output. We use extreme value statistics to show that this procedure considerably improves the representation of climatic extremes and variability. Subsequently, biosphere-atmosphere carbon fluxes are simulated using a terrestrial ecosystem model (LPJ-GSI) to further demonstrate the sensitivity of ecosystem impacts to the methodology of bias correcting climate model output. We find that uncertainties arising from bias correction schemes are comparable in magnitude to model structural and parameter uncertainties. The present study consists of a first attempt to alleviate climate model biases in a physically consistent way and demonstrates that this yields improved simulations of

  13. Iridate compound produces extraordinarily high coercive magnetic field

    Science.gov (United States)

    Zapf, Vivien; Topping, Craig; Kim, Jae-Wook; Mun, Eun-Deok; Goddard, Paul; Ghannadzadeh, Saman; Luo, Xuan; Cheong, Sang-Wook; Singleton, John

    2014-03-01

    We present a data on an iridate compound that shows an extraordinarily large magnetic hysteresis loop. The coercive magnetic field exceeds 40 Tesla in single-crystal samples. The hysteresis coexists with a linear background, and the total remanent magnetization is about half a Bohr magneton. We will discuss the emergence of these properties from the interplay of spin-orbit coupling, magnetic exchange and possible frustration. The single crystalline material exhibits a magnetic hysteresis loop for one orientation of the magnetic field and a smooth linear increase in the magnetization with field for the other. Measurements were conducted in 65 T short-pulse magnets and the 60 Tesla shaped-pulse magnet at the National High Magnetic Field Lab in Los Alamos. We do not observe any dependence of the magnetic hysteresis on magnetic field sweep rate. Compounds containing Ir4 + have attracted attention recently due to strong spin-orbit coupling that competes with crystal-electric field and exchange interactions. This competition can result in non-Hund's-rule ground states with unusual properties.

  14. Hybrid high gradient permanent magnet quadrupole

    Science.gov (United States)

    N'gotta, P.; Le Bec, G.; Chavanne, J.

    2016-12-01

    This paper presents an innovative compact permanent magnet quadrupole with a strong gradient for potential use in future light source lattices. Its magnetic structure includes simple mechanical parts, rectangular permanent magnet blocks and soft iron poles. It has a wide aperture in the horizontal plane to accommodate an x-ray beam port, a common constraint in storage ring-based light sources. This specificity introduces field quality deterioration because of the resulting truncation of the poles; a suitable field quality can be restored with an optimized pole shape. A 82 T /m prototype with a bore radius of 12 mm and a 10 mm vertical gap between poles has been constructed and magnetically characterized. Gradient inhomogeneities better than 10-3 in the good field region were obtained after the installation of special shims.

  15. High-Field Accelerator Magnets Beyond LHC

    CERN Document Server

    Devred, Arnaud

    2003-01-01

    The LHC magnet R&D Program has shown that the limit of NbTi technology at 1.8 K was in the range 10 to 10.5 T. Hence, to go beyond the 10-T threshold, it is necessary to change of superconducting material. Given the state of the art in HTS, the only serious candidate is Nb3Sn. A series of dipole magnet models built at Twente University and LBNL and a vigorous program underway at FNAL have demonstrated the feasibility of Nb3Sn magnet technology. The next step is to bring this technology to maturity, which requires further conductor and conductor insulation development and a simplification of manufacturing processes. After outlining a roadmap to address outstanding issues, we evoke the US proposal for a second generation of LHC Insertion Region (IR) magnets and the Next European Dipole (NED) initiative promoted by the European Steering Group on Accelerator R&D (ESGARD).

  16. Physical Exam Risk Factors for Lower Extremity Injury in High School Athletes: A Systematic Review.

    Science.gov (United States)

    Onate, James A; Everhart, Joshua S; Clifton, Daniel R; Best, Thomas M; Borchers, James R; Chaudhari, Ajit M W

    2016-11-01

    A stated goal of the preparticipation physical evaluation (PPE) is to reduce musculoskeletal injury, yet the musculoskeletal portion of the PPE is reportedly of questionable use in assessing lower extremity injury risk in high school-aged athletes. The objectives of this study are: (1) identify clinical assessment tools demonstrated to effectively determine lower extremity injury risk in a prospective setting, and (2) critically assess the methodological quality of prospective lower extremity risk assessment studies that use these tools. A systematic search was performed in PubMed, CINAHL, UptoDate, Google Scholar, Cochrane Reviews, and SportDiscus. Inclusion criteria were prospective injury risk assessment studies involving athletes primarily ages 13 to 19 that used screening methods that did not require highly specialized equipment. Methodological quality was evaluated with a modified physiotherapy evidence database (PEDro) scale. Nine studies were included. The mean modified PEDro score was 6.0/10 (SD, 1.5). Multidirectional balance (odds ratio [OR], 3.0; CI, 1.5-6.1; P < 0.05) and physical maturation status (P < 0.05) were predictive of overall injury risk, knee hyperextension was predictive of anterior cruciate ligament injury (OR, 5.0; CI, 1.2-18.4; P < 0.05), hip external:internal rotator strength ratio of patellofemoral pain syndrome (P = 0.02), and foot posture index of ankle sprain (r = -0.339, P = 0.008). Minimal prospective evidence supports or refutes the use of the functional musculoskeletal exam portion of the current PPE to assess lower extremity injury risk in high school athletes. Limited evidence does support inclusion of multidirectional balance assessment and physical maturation status in a musculoskeletal exam as both are generalizable risk factors for lower extremity injury.

  17. Physical Exam Risk Factors for Lower Extremity Injury in High School Athletes: A Systematic Review

    Science.gov (United States)

    Onate, James A.; Everhart, Joshua S.; Clifton, Daniel R.; Best, Thomas M.; Borchers, James R.; Chaudhari, Ajit M.W.

    2016-01-01

    Objective A stated goal of the preparticipation physical evaluation (PPE) is to reduce musculoskeletal injury, yet the musculoskeletal portion of the PPE is reportedly of questionable use in assessing lower extremity injury risk in high school-aged athletes. The objectives of this study are: (1) identify clinical assessment tools demonstrated to effectively determine lower extremity injury risk in a prospective setting, and (2) critically assess the methodological quality of prospective lower extremity risk assessment studies that use these tools. Data Sources A systematic search was performed in PubMed, CINAHL, UptoDate, Google Scholar, Cochrane Reviews, and SportDiscus. Inclusion criteria were prospective injury risk assessment studies involving athletes primarily ages 13 to 19 that used screening methods that did not require highly specialized equipment. Methodological quality was evaluated with a modified physiotherapy evidence database (PEDro) scale. Main Results Nine studies were included. The mean modified PEDro score was 6.0/10 (SD, 1.5). Multidirectional balance (odds ratio [OR], 3.0; CI, 1.5–6.1; P anterior cruciate ligament injury (OR, 5.0; CI, 1.2–18.4; P < 0.05), hip external: internal rotator strength ratio of patellofemoral pain syndrome (P = 0.02), and foot posture index of ankle sprain (r = −0.339, P = 0.008). Conclusions Minimal prospective evidence supports or refutes the use of the functional musculoskeletal exam portion of the current PPE to assess lower extremity injury risk in high school athletes. Limited evidence does support inclusion of multidirectional balance assessment and physical maturation status in a musculoskeletal exam as both are generalizable risk factors for lower extremity injury. PMID:26978166

  18. L10-MnGa based magnetic tunnel junction for high magnetic field sensor

    Science.gov (United States)

    Zhao, X. P.; Lu, J.; Mao, S. W.; Yu, Z. F.; Wang, H. L.; Wang, X. L.; Wei, D. H.; Zhao, J. H.

    2017-07-01

    We report on the investigation of the magnetic tunnel junction structure designed for high magnetic field sensors with a perpendicularly magnetized L10-MnGa reference layer and an in-plane magnetized Fe sensing layer. A large linear tunneling magnetoresistance ratio up to 27.4% and huge dynamic range up to 5600 Oe have been observed at 300 K, with a low nonlinearity of 0.23% in the optimized magnetic tunnel junction (MTJ). The field response of tunneling magnetoresistance is discussed to explain the field sensing properties in the dynamic range. These results indicate that L10-MnGa based orthogonal MTJ is a promising candidate for a high performance magnetic field sensor with a large dynamic range, high endurance and low power consumption.

  19. Establishing resolution-improved NMR spectroscopy in high magnetic fields with unknown spatiotemporal variations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhiyong; Cai, Shuhui; Zheng, Zhenyao; Lin, Yulan, E-mail: chenz@xmu.edu.cn, E-mail: lylfj2005@xmu.edu.cn; Chen, Zhong, E-mail: chenz@xmu.edu.cn, E-mail: lylfj2005@xmu.edu.cn [Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen (China); Smith, Pieter E. S. [Chemical Physics Department, Weizmann Institute of Science, Rehovot (Israel)

    2015-12-28

    A half-century quest for higher magnetic fields has been an integral part of the progress undergone in the Nuclear Magnetic Resonance (NMR) study of materials’ structure and dynamics. Because 2D NMR relies on systematic changes in coherences’ phases as a function of an encoding time varied over a series of independent experiments, it generally cannot be applied in temporally unstable fields. This precludes most NMR methods from being used to characterize samples situated in hybrid or resistive magnets that are capable of achieving extremely high magnetic field strength. Recently, “ultrafast” NMR has been developed into an effective and widely applicable methodology enabling the acquisition of a multidimensional NMR spectrum in a single scan; it can therefore be used to partially mitigate the effects of temporally varying magnetic fields. Nevertheless, the strong interference of fluctuating fields with the spatial encoding of ultrafast NMR still severely restricts measurement sensitivity and resolution. Here, we introduce a strategy for obtaining high resolution NMR spectra that exploits the immunity of intermolecular zero-quantum coherences (iZQCs) to field instabilities and inhomogeneities. The spatial encoding of iZQCs is combined with a J-modulated detection scheme that removes the influence of arbitrary field inhomogeneities during acquisition. This new method can acquire high-resolution one-dimensional NMR spectra in large inhomogeneous and fluctuating fields, and it is tested with fields experimentally modeled to mimic those of resistive and resistive-superconducting hybrid magnets.

  20. Extreme changes in the dayside ionosphere during a Carrington-type magnetic storm

    Directory of Open Access Journals (Sweden)

    Mannucci Anthony J.

    2012-06-01

    Full Text Available It is shown that during the 30 October 2003 superstorm, dayside O+ ions were uplifted to DMSP altitudes (~850 km. Peak densities were ~9 × 105 cm−3 during the magnetic storm main phase (peak Dst = −390 nT. By comparison the 1–2 September 1859 Carrington magnetic storm (peak Dst estimated at −1760 nT was considerably stronger. We investigate the impact of this storm on the low- to mid-latitude ionosphere using a modified version of the NRL SAMI2 ionospheric code. It is found that the equatorial region (LAT = 0° ± 15° is swept free of plasma within 15 min (or less of storm onset. The plasma is swept to higher altitudes and higher latitudes due to E × B convection associated with the prompt penetration electric field. Equatorial Ionization Anomaly (EIA O+ density enhancements are found to be located within the broad range of latitudes ~ ± (25°–40° at ~500–900 km altitudes. Densities within these peaks are ~6 × 106 oxygen ions-cm−3 at ~700 km altitude, approximately +600% quiet time values. The oxygen ions at the top portions (850–1000 km of uplifted EIAs will cause strong low-altitude satellite drag. Calculations are currently being performed on possible uplift of oxygen neutrals by ion-neutral coupling to understand if there might be further significant satellite drag forces present.

  1. Investigation of EEG changes during exposure to extremely low-frequency magnetic field to conduct brain signals.

    Science.gov (United States)

    Shafiei, S A; Firoozabadi, S M; Tabatabaie, K Rasoulzadeh; Ghabaee, M

    2014-11-01

    There are evidences that confirm the effect of magnetic fields (MFs) on brain signals and some psychological disorders such as headache, migraine and depression. The aim of the present study was to investigate changes in EEG power spectrum due to localized exposure in different parts of the brain by extremely low-frequency magnetic fields (ELF-MFs) to extract some protocols for treatment of some psychological disorders. In addition, regular effects were investigated by increasing intensity of ELF-MF. Therefore, EEG relative power spectrum was evaluated at T4, T3, F3, F4, and Cz points, when all the points were exposed to MFs with 45, 17, 10, 5, and 3 Hz frequencies, separately. Intensity of MF was 0, 100, 240, or 360 μT in four sessions. Significant changes were observed in different EEG bands caused by locally exposing to ELF-MF in different points of brain (P conduct the brain signals that is necessary to evaluate clinically.

  2. 3T3 cell motility and morphology before, during, and after exposure to extremely-low-frequency magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Spadinger, I.; Palcic, B. [British Columbia Cancer Research Centre, Vancouver, British Columbia (Canada). Cancer Imaging; Agnew, D. [Ontario Hydro, Whitby, Ontario (Canada). Health and Safety Div.

    1995-08-01

    Automated image cytometry techniques were used to measure motility and morphology in 3T3 fibro-blasts exposed to extremely-low-frequency (ELF) magnetic fields. Cell motility and morphology were measured as a function of time before, during, and after 3--4 hour exposures to vertically oriented, 100 {mu}T{sub RMS} sinusoidal magnetic fields at various frequencies in the 10--63 Hz range. Sham exposures were also carried out. No static DC fields were applied, but the geomagnetic field was almost vertical and, therefore, had a large component (28.3 {mu}T) parallel to the applied AC field. The morphology and motile behavior of the cells were characterized by mathematically defined descriptors, which were calculated and averaged for the exposure period as well as for control periods that preceded and followed the exposure period. Each experiment involved the tracking of 100 cells that were subjected to one of the test frequencies (unless a sham exposure was being conducted). Statistical analysis of the results showed that even small changes of 10--20% could be significant at the P < .05 level. Changes on this order were measured in a significant proportion of the experiments. However, because such results were seen for both the sham-exposed and the ELF-exposed cells, and because the range of values that was obtained for the sham exposures was the same as that obtained for the ELF exposures, the authors concluded that there was no evidence to show that any of the measured changes were attributable to the applied ELF magnetic field.

  3. Destroying a near-extremal Kerr black hole with a charged particle: Can a test magnetic field serve as a cosmic censor?

    CERN Document Server

    Shaymatov, Sanjar; Ahmedov, Bobomurat; Joshi, Pankaj S

    2014-01-01

    We investigate effect of a test magnetic field on the process of destroying near-extremal Kerr black hole with a charged test particle. It has been shown that it would be possible to throw a charged test particle into the near extremal rotating black hole and make it go past the extremality i.e. turn Kerr black hole into the Kerr-Newmann naked singularity. Typically in an astrophysical scenario black holes are believed to be surrounded by a magnetic field. Magnetic field although small, affects motion of charged particles drastically due to the large Lorentz force, as the electromagnetic force is much stronger that the gravity. Thus a test magnetic field can affect the process of destroying black holes and restore the cosmic censorship in the astrophysical context. We show that a test magnetic field would act as a cosmic censor beyond a certain threshold value. We try to gauge the magnitude of the magnetic field by comparing its energy density with that of the change in the curvature induced by the test parti...

  4. Controllable preparation of high-yield magnetic polymer latex.

    Science.gov (United States)

    Wu, Chun-Chao; Kong, Xiang-Ming; Yang, Hai-Long

    2011-09-01

    In order to overcome the low conversion and complex post-treatment, four different polymerization procedures were adopted to prepare the magnetic polymer latexes. The results clearly show that the strategy using magnetic emulsion template-dosage is the most effective and feasible. Based on the optimized procedure, various factors including the type of initiators such as oil soluble initiator, water soluble initiator, redox initiator system, crosslinking agent, functional monomers etc. were systematically studied. Magnetic polymer latex with high monomer conversion of 83% and high magnet content of 31.8% was successfully obtained. Besides, core-shell structured magnetic polymer latex with good film forming property was also prepared, which is promising for potential applications such as magnetic coatings and modification of cementitious materials with controlled polymer location.

  5. High-aspect ratio magnetic nanocomposite polymer cilium

    Science.gov (United States)

    Rahbar, M.; Tseng, H. Y.; Gray, B. L.

    2014-03-01

    This paper presents a new fabrication technique to achieve ultra high-aspect ratio artificial cilia micro-patterned from flexible highly magnetic rare earth nanoparticle-doped polymers. We have developed a simple, inexpensive and scalable fabrication method to create cilia structures that can be actuated by miniature electromagnets, that are suitable to be used for lab-on-a chip (LOC) and micro-total-analysis-system (μ-TAS) applications such as mixers and flow-control elements. The magnetic cilia are fabricated and magnetically polarized directly in microfluidic channels or reaction chambers, allowing for easy integration with complex microfluidic systems. These cilia structures can be combined on a single chip with other microfluidic components employing the same permanently magnetic nano-composite polymer (MNCP), such as valves or pumps. Rare earth permanent magnetic powder, (Nd0.7Ce0.3)10.5Fe83.9B5.6, is used to dope polydimethylsiloxane (PDMS), resulting in a highly flexible M-NCP of much higher magnetization and remanence [1] than ferromagnetic polymers typically employed in magnetic microfluidics. Sacrificial poly(ethylene-glycol) (PEG) is used to mold the highly magnetic polymer into ultra high-aspect ratio artificial cilia. Cilia structures with aspect ratio exceeding 8:0.13 can be easily fabricated using this technique and are actuated using miniature electromagnets to achieve a high range of motion/vibration.

  6. High Performance Magnetic Bearings for Aero Applications

    Science.gov (United States)

    Allaire, P. E.; Knospe, C. R.; Williams, R. D.; Lewis, D. W.; Barrett, L. E.; Maslen, E. H.; Humphris, R. R.

    1997-01-01

    Several previous annual reports were written and numerous papers published on the topics for this grant. That work is not repeated here in this final report. Only the work completed in the final year of the grant is presented in this final report. This final year effort concentrated on power loss measurements in magnetic bearing rotors. The effect of rotor power losses in magnetic bearings are very important for many applications. In some cases, these losses must be minimized to maximize the length of time the rotating machine can operate on a fixed energy or power supply. Examples include aircraft gas turbine engines, space devices, or energy storage flywheels. In other applications, the heating caused by the magnetic bearing must be removed. Excessive heating can be a significant problem in machines as diverse as large compressors, electric motors, textile spindles, and artificial heart pumps.

  7. High Temperature, Permanent Magnet Biased, Fault Tolerant, Homopolar Magnetic Bearing Development

    Science.gov (United States)

    Palazzolo, Alan; Tucker, Randall; Kenny, Andrew; Kang, Kyung-Dae; Ghandi, Varun; Liu, Jinfang; Choi, Heeju; Provenza, Andrew

    2008-01-01

    This paper summarizes the development of a magnetic bearing designed to operate at 1,000 F. A novel feature of this high temperature magnetic bearing is its homopolar construction which incorporates state of the art high temperature, 1,000 F, permanent magnets. A second feature is its fault tolerance capability which provides the desired control forces with over one-half of the coils failed. The construction and design methodology of the bearing is outlined and test results are shown. The agreement between a 3D finite element, magnetic field based prediction for force is shown to be in good agreement with predictions at room and high temperature. A 5 axis test rig will be complete soon to provide a means to test the magnetic bearings at high temperature and speed.

  8. Large Differences in Bacterial Community Composition among Three Nearby Extreme Waterbodies of the High Andean Plateau.

    Science.gov (United States)

    Aguilar, Pablo; Acosta, Eduardo; Dorador, Cristina; Sommaruga, Ruben

    2016-01-01

    The high Andean plateau or Altiplano contains different waterbodies that are subjected to extreme fluctuations in abiotic conditions on a daily and an annual scale. The bacterial diversity and community composition of those shallow waterbodies is largely unexplored, particularly, of the ponds embedded within the peatland landscape (i.e., Bofedales). Here we compare the small-scale spatial variability (Altiplano peatland ponds represent a hitherto unknown source of microbial diversity.

  9. B-2 Extremely High Frequency SATCOM and Computer Increment 1 (B-2 EHF Inc 1)

    Science.gov (United States)

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-224 B-2 Extremely High Frequency SATCOM and Computer Increment 1 (B-2 EHF Inc 1) As of FY...10 Track to Budget 11 Cost and Funding 13 Low Rate Initial Production 19 Foreign Military Sales 20 Nuclear Costs 20 Unit Cost...Document CLIN - Contract Line Item Number CPD - Capability Production Document CY - Calendar Year DAB - Defense Acquisition Board DAE - Defense

  10. Environmental Assessment for the Advanced Extremely High Frequency Satellite Beddown and Deployment Program

    Science.gov (United States)

    2010-07-01

    Fish and Wildlife Service Advanced Extremely High Frequency Satellite Final Environmental Assessment v VIF Vehicle Integration Facility WMO World...Vehicle Mate Operations Upon arrival on CCAFS, the transporter would take the encapsulated payload to the Vehicle Integration Facility ( VIF ), which...is located just south of LC-41 (Figure 2-2). At the VIF , the encapsulated payload would be mated to the Atlas V Launch Vehicle (LV) using a mobile

  11. Liquid Droplet Dynamics in Gravity Compensating High Magnetic Field

    Science.gov (United States)

    Bojarevics, V.; Easter, S.; Pericleous, K.

    2012-01-01

    Numerical models are used to investigate behavior of liquid droplets suspended in high DC magnetic fields of various configurations providing microgravity-like conditions. Using a DC field it is possible to create conditions with laminar viscosity and heat transfer to measure viscosity, surface tension, electrical and thermal conductivities, and heat capacity of a liquid sample. The oscillations in a high DC magnetic field are quite different for an electrically conducting droplet, like liquid silicon or metal. The droplet behavior in a high magnetic field is the subject of investigation in this paper. At the high values of magnetic field some oscillation modes are damped quickly, while others are modified with a considerable shift of the oscillating droplet frequencies and the damping constants from the non-magnetic case.

  12. Ultrastructure and calcium balance in meristem cells of pea roots exposed to extremely low magnetic fields

    Science.gov (United States)

    Belyavskaya, N. A.

    2001-01-01

    Investigations of low magnetic field (LMF) effects on biological systems have attracted attention of biologists due to planned space flights to other planets where the field intensity does not exceed 10 -5 Oe. Pea ( Pisum sativum L.) seeds were grown in an environment of LMF 3 days. In meristem cells of roots exposed to LMF, one could observe such ultrastructural peculiarities as a noticeable accumulation of lipid bodies, development of a lytic compartment (vacuoles, cytosegresomes and paramural bodies), and reduction of phytoferritin in plastids. Mitochondria were the most sensitive organelle to LMF application. Their size and relative volume in cells increased, matrix was electron-transparent, and cristae reduced. Because of the significant role of calcium signalling in plant responses to different environmental factors, calcium participation in LMF effects was investigated using a pyroantimonate method to identify the localization of free calcium ions. The intensity of cytochemical reaction in root cells after LMF application was strong. The Ca 2+ pyroantimonate deposits were observed both in all organelles and in a hyaloplasm of the cells. Data obtained suggest that the observed LMF effects on ultrastructure of root cells were due to disruptions in different metabolic systems including effects on Ca 2+ homeostasis.

  13. Highly Sensitive Flexible Magnetic Sensor Based on Anisotropic Magnetoresistance Effect.

    Science.gov (United States)

    Wang, Zhiguang; Wang, Xinjun; Li, Menghui; Gao, Yuan; Hu, Zhongqiang; Nan, Tianxiang; Liang, Xianfeng; Chen, Huaihao; Yang, Jia; Cash, Syd; Sun, Nian-Xiang

    2016-11-01

    A highly sensitive flexible magnetic sensor based on the anisotropic magnetoresistance effect is fabricated. A limit of detection of 150 nT is observed and excellent deformation stability is achieved after wrapping of the flexible sensor, with bending radii down to 5 mm. The flexible AMR sensor is used to read a magnetic pattern with a thickness of 10 μm that is formed by ferrite magnetic inks.

  14. Limits to the thermal tolerance of corals adapted to a highly fluctuating, naturally extreme temperature environment

    Science.gov (United States)

    Schoepf, Verena; Stat, Michael; Falter, James L.; McCulloch, Malcolm T.

    2015-12-01

    Naturally extreme temperature environments can provide important insights into the processes underlying coral thermal tolerance. We determined the bleaching resistance of Acropora aspera and Dipsastraea sp. from both intertidal and subtidal environments of the naturally extreme Kimberley region in northwest Australia. Here tides of up to 10 m can cause aerial exposure of corals and temperatures as high as 37 °C that fluctuate daily by up to 7 °C. Control corals were maintained at ambient nearshore temperatures which varied diurnally by 4-5 °C, while treatment corals were exposed to similar diurnal variations and heat stress corresponding to ~20 degree heating days. All corals hosted Symbiodinium clade C independent of treatment or origin. Detailed physiological measurements showed that these corals were nevertheless highly sensitive to daily average temperatures exceeding their maximum monthly mean of ~31 °C by 1 °C for only a few days. Generally, Acropora was much more susceptible to bleaching than Dipsastraea and experienced up to 75% mortality, whereas all Dipsastraea survived. Furthermore, subtidal corals, which originated from a more thermally stable environment compared to intertidal corals, were more susceptible to bleaching. This demonstrates that while highly fluctuating temperatures enhance coral resilience to thermal stress, they do not provide immunity to extreme heat stress events.

  15. [Membranotropic effects of electromagnetic radiation of extremely high frequency on Escherichia coli].

    Science.gov (United States)

    Trchunian, A; Ogandzhanian, E; Sarkisian, E; Gonian, S; Oganesian, A; Oganesian, S

    2001-01-01

    It was found that "sound" electromagnetic radiations of extremely high frequencies (53.5-68 GHz) or millimeter waves (wavelength range of 4.2-5.6 mm) of low intensity (power density 0.01 mW) have a bactericidal effect on Escherichia coli bacteria. It was shown that exposure to irradiation of extremely high frequencies increases the electrokinetic potential and surface change density of bacteria and decreases of membrane potential. The total secretion of hydrogen ions was suppressed, the H+ flux from the cytoplasm to medium decreased, and the flux of N,N'-dicyclohexylcarbodiimide-sensitive potassium ions increased, which was accompanied by changes in the stoichiometry of these fluxes and an increase in the sensitivity of H+ ions to N,N'-dicyclohexylcarbodiimide. The effects depended on duration of exposure: as the time of exposure increased, the bactericidal effect increased, whereas the membranotropic effects decreased. The effects also depended on growth phase of bacteria: the irradiation affected the cells in the stationary but not in the logarithmic phase. It is assumed that the H(+)-ATPase complex F0F1 is involved in membranotropic effects of electromagnetic radiation of extremely high frequencies. Presumably, there are some compensatory mechanisms that eliminate the membranotropic effects.

  16. Limits to the thermal tolerance of corals adapted to a highly fluctuating, naturally extreme temperature environment.

    Science.gov (United States)

    Schoepf, Verena; Stat, Michael; Falter, James L; McCulloch, Malcolm T

    2015-12-02

    Naturally extreme temperature environments can provide important insights into the processes underlying coral thermal tolerance. We determined the bleaching resistance of Acropora aspera and Dipsastraea sp. from both intertidal and subtidal environments of the naturally extreme Kimberley region in northwest Australia. Here tides of up to 10 m can cause aerial exposure of corals and temperatures as high as 37 °C that fluctuate daily by up to 7 °C. Control corals were maintained at ambient nearshore temperatures which varied diurnally by 4-5 °C, while treatment corals were exposed to similar diurnal variations and heat stress corresponding to ~20 degree heating days. All corals hosted Symbiodinium clade C independent of treatment or origin. Detailed physiological measurements showed that these corals were nevertheless highly sensitive to daily average temperatures exceeding their maximum monthly mean of ~31 °C by 1 °C for only a few days. Generally, Acropora was much more susceptible to bleaching than Dipsastraea and experienced up to 75% mortality, whereas all Dipsastraea survived. Furthermore, subtidal corals, which originated from a more thermally stable environment compared to intertidal corals, were more susceptible to bleaching. This demonstrates that while highly fluctuating temperatures enhance coral resilience to thermal stress, they do not provide immunity to extreme heat stress events.

  17. Nitrogen accumulation and partitioning in a High Arctic tundra ecosystem from extreme atmospheric N deposition events.

    Science.gov (United States)

    Choudhary, Sonal; Blaud, Aimeric; Osborn, A Mark; Press, Malcolm C; Phoenix, Gareth K

    2016-06-01

    Arctic ecosystems are threatened by pollution from recently detected extreme atmospheric nitrogen (N) deposition events in which up to 90% of the annual N deposition can occur in just a few days. We undertook the first assessment of the fate of N from extreme deposition in High Arctic tundra and are presenting the results from the whole ecosystem (15)N labelling experiment. In 2010, we simulated N depositions at rates of 0, 0.04, 0.4 and 1.2 g Nm(-2)yr(-1), applied as (15)NH4(15)NO3 in Svalbard (79(°)N), during the summer. Separate applications of (15)NO3(-) and (15)NH4(+) were also made to determine the importance of N form in their retention. More than 95% of the total (15)N applied was recovered after one growing season (~90% after two), demonstrating a considerable capacity of Arctic tundra to retain N from these deposition events. Important sinks for the deposited N, regardless of its application rate or form, were non-vascular plants>vascular plants>organic soil>litter>mineral soil, suggesting that non-vascular plants could be the primary component of this ecosystem to undergo measurable changes due to N enrichment from extreme deposition events. Substantial retention of N by soil microbial biomass (70% and 39% of (15)N in organic and mineral horizon, respectively) during the initial partitioning demonstrated their capacity to act as effective buffers for N leaching. Between the two N forms, vascular plants (Salix polaris) in particular showed difference in their N recovery, incorporating four times greater (15)NO3(-) than (15)NH4(+), suggesting deposition rich in nitrate will impact them more. Overall, these findings show that despite the deposition rates being extreme in statistical terms, biologically they do not exceed the capacity of tundra to sequester pollutant N during the growing season. Therefore, current and future extreme events may represent a major source of eutrophication.

  18. Nitrogen accumulation and partitioning in a High Arctic tundra ecosystem from extreme atmospheric N deposition events

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, Sonal, E-mail: S.Choudhary@sheffield.ac.uk [Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Management School, University of Sheffield, Conduit Road, Sheffield S10 1FL (United Kingdom); Blaud, Aimeric [Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Osborn, A. Mark [Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); School of Applied Sciences, RMIT University, PO Box 71, Bundoora, VIC 3083 (Australia); Press, Malcolm C. [School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Manchester Metropolitan University, Manchester, M15 6BH (United Kingdom); Phoenix, Gareth K. [Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom)

    2016-06-01

    Arctic ecosystems are threatened by pollution from recently detected extreme atmospheric nitrogen (N) deposition events in which up to 90% of the annual N deposition can occur in just a few days. We undertook the first assessment of the fate of N from extreme deposition in High Arctic tundra and are presenting the results from the whole ecosystem {sup 15}N labelling experiment. In 2010, we simulated N depositions at rates of 0, 0.04, 0.4 and 1.2 g N m{sup −2} yr{sup −1}, applied as {sup 15}NH{sub 4}{sup 15}NO{sub 3} in Svalbard (79{sup °}N), during the summer. Separate applications of {sup 15}NO{sub 3}{sup −} and {sup 15}NH{sub 4}{sup +} were also made to determine the importance of N form in their retention. More than 95% of the total {sup 15}N applied was recovered after one growing season (~ 90% after two), demonstrating a considerable capacity of Arctic tundra to retain N from these deposition events. Important sinks for the deposited N, regardless of its application rate or form, were non-vascular plants > vascular plants > organic soil > litter > mineral soil, suggesting that non-vascular plants could be the primary component of this ecosystem to undergo measurable changes due to N enrichment from extreme deposition events. Substantial retention of N by soil microbial biomass (70% and 39% of {sup 15}N in organic and mineral horizon, respectively) during the initial partitioning demonstrated their capacity to act as effective buffers for N leaching. Between the two N forms, vascular plants (Salix polaris) in particular showed difference in their N recovery, incorporating four times greater {sup 15}NO{sub 3}{sup −} than {sup 15}NH{sub 4}{sup +}, suggesting deposition rich in nitrate will impact them more. Overall, these findings show that despite the deposition rates being extreme in statistical terms, biologically they do not exceed the capacity of tundra to sequester pollutant N during the growing season. Therefore, current and future extreme events

  19. High-resolution projections of mean and extreme precipitations over China through PRECIS under RCPs

    Science.gov (United States)

    Zhu, Jinxin; Huang, Gordon; Wang, Xiuquan; Cheng, Guanhui; Wu, Yinghui

    2017-08-01

    The impact of global warming on the characteristics of mean and extreme precipitations over China is investigated by using the Providing REgional Climate Impacts for Studies (PRECIS) model. The PRECIS model was driven by the Hadley Centre Global Environment Model version 2 with Earth System components and coupling (HadGEM2-ES). The results of both models are analyzed in terms of mean precipitation and indices of precipitation extremes (R95p, R99p, SDII, WDF, and CWD) over China at the resolution of 25 km under the Representative Concentration Pathways 4.5 and 8.5 (RCP4.5 and RCP8.5) scenarios for the baseline period (1976-2005) and two future periods (2036-2065 and 2070-2099). With improved resolution, the PRECIS model is able to better represent the fine-scale physical process than HadGEM2-ES. It can provide reliable spatial patterns of precipitation and its related extremes with high correlations to observations. Moreover, there is a notable improvement in temporal patterns simulation through the PRECIS model. The PRECIS model better reproduces the regional annual cycle and frequencies of daily precipitation intensity than its driving GCM. Under RCP4.5 and RCP8.5, both the HadGEM2-ES and the precis project increasing annual precipitation over the entire country for two future periods. Precipitation increase in winter is greater than the increase in summer. The results suggest that increased radiative forcing from RCP4.5 to RCP8.5 would further intensify the magnitude of projected precipitation changes by both PRECIS and HadGEM2-ES. For example, some parts of south China with decreased precipitation under RCP4.5 would expect even less precipitation under RCP8.5; regions (northwest, northcentral and northeast China) with increased precipitation under RCP4.5 would expect more precipitation under RCP8.5. Apart from the projected increase in annual total precipitation, the results also suggest that there will be an increase in the days with precipitation higher than

  20. Multiplex APLP System for High-Resolution Haplogrouping of Extremely Degraded East-Asian Mitochondrial DNAs

    Science.gov (United States)

    Kakuda, Tsuneo; Shojo, Hideki; Tanaka, Mayumi; Nambiar, Phrabhakaran; Minaguchi, Kiyoshi; Umetsu, Kazuo; Adachi, Noboru

    2016-01-01

    Mitochondrial DNA (mtDNA) serves as a powerful tool for exploring matrilineal phylogeographic ancestry, as well as for analyzing highly degraded samples, because of its polymorphic nature and high copy numbers per cell. The recent advent of complete mitochondrial genome sequencing has led to improved techniques for phylogenetic analyses based on mtDNA, and many multiplex genotyping methods have been developed for the hierarchical analysis of phylogenetically important mutations. However, few high-resolution multiplex genotyping systems for analyzing East-Asian mtDNA can be applied to extremely degraded samples. Here, we present a multiplex system for analyzing mitochondrial single nucleotide polymorphisms (mtSNPs), which relies on a novel amplified product-length polymorphisms (APLP) method that uses inosine-flapped primers and is specifically designed for the detailed haplogrouping of extremely degraded East-Asian mtDNAs. We used fourteen 6-plex polymerase chain reactions (PCRs) and subsequent electrophoresis to examine 81 haplogroup-defining SNPs and 3 insertion/deletion sites, and we were able to securely assign the studied mtDNAs to relevant haplogroups. Our system requires only 1×10−13 g (100 fg) of crude DNA to obtain a full profile. Owing to its small amplicon size (<110 bp), this new APLP system was successfully applied to extremely degraded samples for which direct sequencing of hypervariable segments using mini-primer sets was unsuccessful, and proved to be more robust than conventional APLP analysis. Thus, our new APLP system is effective for retrieving reliable data from extremely degraded East-Asian mtDNAs. PMID:27355212

  1. Ultra-high-field superconducting magnets

    Energy Technology Data Exchange (ETDEWEB)

    Hoard, R.W.; Cornish, D.N.; Scanlan, R.M.; Zbasnik, J.P.; Leber, R.L.; Hickman, R.B.; Lee, J.D.

    1983-08-01

    The following topics are considered: (1) superfluid helium for advanced magnets, (2) conductor reinforcement, (3) designing a 20-T, 2-m bore solenoidal coil, (4) coil size and conductor properties, (5) axial forces on the coil, (6) effect of radiation on the coil systems, and (7) helium-II transient heat transfer and coil protection. (MOW)

  2. High performance magnetocaloric perovskites for magnetic refrigeration

    DEFF Research Database (Denmark)

    Bahl, Christian R. H.; Velazquez, David; Nielsen, Kaspar K.

    2012-01-01

    We have applied mixed valance manganite perovskites as magnetocaloric materials in a magnetic refrigeration device. Relying on exact control of the composition and a technique to process the materials into single adjoined pieces, we have observed temperature spans above 9 K with two materials. Re...

  3. Impact of the extreme 2009 wildfire Victoria the wettability of naturally highly water repellent soils

    Science.gov (United States)

    Doerr, Stefan H.; Shakesby, Richard A.; Sheridan, Gary J.; Lane, Patrick Nj; Smith, Hugh G.; Bell, Tina; Blake, William H.

    2010-05-01

    The recent catastrophic wildfires near Melbourne, which peaked on Feb. 7 2009, burned ca 400,000 ha and caused the tragic loss of 173 people. They occurred during unprecedented extreme fire weather where dry northerly winds gusting up to 100 km/h coincided with the highest temperatures ever recorded in this region. These conditions, combined with the very high biomass of mature eucalypt forests, very low fuel moisture conditions and steep slopes, generated extreme burning conditions. A rapid response project was launched under the NERC Urgency Scheme aimed at determining the effects of this extreme event on soil properties. Three replicate sites each were sampled for extremely high burn severity, high burn severity and unburnt control terrain, within mature mixed-species eucalypt forests near Marysville in April 2009. Ash and surface soil (0-2.5 cm and 2.5-5 cm) were collected at 20 sample grid points at each site. Here we report on outcomes from Water Drop Penetration Time (WDPT) tests carried out on soil samples to determine the impact of this extreme event on the wettability of a naturally highly water repellent soil. Field assessment suggested that the impact of this extreme wildfire on the soil was less than might be supposed given the extreme burn severity (indicated by the complete elimination of the ground vegetation). This was confirmed by the laboratory results. No major difference in WDPT was detected between (i) burned and control samples, and (ii) between surface and subsurface WDPT patterns, indicating that soil temperatures in the top 0-2.5 cm did not exceed ~200° C. Seedling germination in burned soil was reduced by at least 2/3 compared to the control samples, however, this reduction is indicative an only modest heat input into the soil. The limited heat input into the soil stands in stark contrast to the extreme burn severity (based on vegetation destruction parameters). We speculate that limited soil heating resulted perhaps from the unusually

  4. Rotating sample magnetometer for cryogenic temperatures and high magnetic fields.

    Science.gov (United States)

    Eisterer, M; Hengstberger, F; Voutsinas, C S; Hörhager, N; Sorta, S; Hecher, J; Weber, H W

    2011-06-01

    We report on the design and implementation of a rotating sample magnetometer (RSM) operating in the variable temperature insert (VTI) of a cryostat equipped with a high-field magnet. The limited space and the cryogenic temperatures impose the most critical design parameters: the small bore size of the magnet requires a very compact pick-up coil system and the low temperatures demand a very careful design of the bearings. Despite these difficulties the RSM achieves excellent resolution at high magnetic field sweep rates, exceeding that of a typical vibrating sample magnetometer by about a factor of ten. In addition the gas-flow cryostat and the high-field superconducting magnet provide a temperature and magnetic field range unprecedented for this type of magnetometer.

  5. High magnetic field test of bismuth Hall sensors for ITER steady state magnetic diagnostic

    Science.gov (United States)

    Duran, I.; Entler, S.; Kohout, M.; Kočan, M.; Vayakis, G.

    2016-11-01

    Performance of bismuth Hall sensors developed for the ITER steady state magnetic diagnostic was investigated for high magnetic fields in the range ±7 T. Response of the sensors to the magnetic field was found to be nonlinear particularly within the range ±1 T. Significant contribution of the planar Hall effect to the sensors output voltage causing undesirable cross field sensitivity was identified. It was demonstrated that this effect can be minimized by the optimization of the sensor geometry and alignment with the magnetic field and by the application of "current-spinning technique."

  6. Counting Extra Dimensions Magnetic Cherenkov Radiation from High Energy Neutrinos

    CERN Document Server

    Domokos, Gabor K; Kövesi-Domokos, S; Erdas, Andrea

    2003-01-01

    In theories which require a space of dimension d > 4, there is a natural mechanism of suppressing neutrino masses: while Standard Model fields are confined to a 3-brane, right handed neutrinos live in the bulk. Due to Kaluza-Klein excitations, the effective magnetic moments of neutrinos are enhanced. The effective magnetic moment is a monotonically growing function of the energy of the neutrino: consequently, high energy neutrinos can emit observable amounts of magnetic Cherenkov radiation. By observing the energy dependence of the magnetic Cherenkov radiation, one may be able to determine the number of compactified dimensions.

  7. A High-Throughput SU-8Microfluidic Magnetic Bead Separator

    DEFF Research Database (Denmark)

    Bu, Minqiang; Christensen, T. B.; Smistrup, Kristian

    2007-01-01

    We present a novel microfluidic magnetic bead separator based on SU-8 fabrication technique for high through-put applications. The experimental results show that magnetic beads can be captured at an efficiency of 91 % and 54 % at flow rates of 1 mL/min and 4 mL/min, respectively. Integration...... of soft magnetic elements in the chip leads to a slightly higher capturing efficiency and a more uniform distribution of captured beads over the separation chamber than the system without soft magnetic elements....

  8. Magnetic-flux dynamics of high-Tc superconductors in weak magnetic fields

    DEFF Research Database (Denmark)

    Il’ichev, E. V.; Jacobsen, Claus Schelde

    1994-01-01

    Aspects of magnetic-flux dynamics in different types of samples of the high-temperature superconductor YBa2Cu3Ox have been investigated in magnetic fields below 1 Oe and at 77 K. The experiments were carried out in an arrangement including a field coil, a flat sample perpendicular to the field...

  9. Extreme risk taker who wants to continue taking part in high risk sports after serious injury.

    Science.gov (United States)

    Pain, M; Kerr, J H

    2004-06-01

    The case is reported of a 40 year old male high risk sport athlete who had seriously injured himself several times and as a result was partially physically disabled and had trouble with mental tasks requiring concentration such as spelling, reading numbers, and writing. The athlete was referred to a sports psychologist. In consultations, it became clear that he was having difficulty reconciling the difference between his life as it used to be and as it would be in the future. Part of his difficulty was dealing with the frustration and anger "outbursts" which resulted from not being able to perform straightforward everyday motor skills. In spite of his injuries and disability, the patient badly wanted to continue participating in extreme sports. Reversal theory is used in the discussion to provide theoretical explanations of the motivation for his extreme risk taking behaviour.

  10. Carbon coatings for extreme-ultraviolet high-order laser harmonics

    Energy Technology Data Exchange (ETDEWEB)

    Coraggia, S.; Frassetto, F. [CNR-Institute of Photonics and Nanotechnologies, Laboratory for UV and X-Ray Optical Research, via Trasea 7, 35131 Padova (Italy); Aznarez, J.A.; Larruquert, J.I.; Mendez, J.A. [GOLD-Instituto de Optica-Consejo Superior de Investigaciones Cientificas, Serrano 144, 28006 Madrid (Spain); Negro, M.; Stagira, S.; Vozzi, C. [Department of Physics-Politecnico of Milano and CNR-Institute of Photonics and Nanotechnologies, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy); Poletto, L., E-mail: poletto@dei.unipd.i [CNR-Institute of Photonics and Nanotechnologies, Laboratory for UV and X-Ray Optical Research, via Trasea 7, 35131 Padova (Italy)

    2011-04-11

    The experimental study of the optical properties of thin carbon films to be used as grazing-incidence coatings for extreme-ultraviolet high-order harmonics is presented. The carbon samples were deposited on plane glass substrates by the electron beam evaporation technique. The optical constants (real and imaginary parts of the refraction index) have been calculated through reflectivity measurements. The results are in good agreement with what reported in the literature, and confirm that carbon-coated optics operated at grazing incidence have a remarkable gain over conventional metallic coatings in the extreme ultraviolet. Since the harmonics co-propagate with the intense infrared laser generating beam, the carbon damage threshold when exposed to ultrashort infrared laser pulses has been measured.

  11. Phase Quantization Study of Spatial Light Modulator for Extreme High contrast Imaging

    CERN Document Server

    Dou, Jiangpei

    2016-01-01

    Direct imaging of exoplanets by reflected starlight is extremely challenging due to the large luminosity ratio to the primary star. Wave front control is a critical technique to attenuate the speckle noise in order to achieve an extreme high contrast. We present the phase quantization study of spatial light modulator for wave front control to meet the contrast requirement of detection of a terrestrial planet in the habitable zone of a solar-type star. We perform the numerical simulation by employing the SLM with different phase accuracy and actuator numbers, which are related to the achievable contrast. We use an optimization algorithm to solve the quantization problems that is matched to the controllable phase step of the SLM. Two optical configurations are discussed with the SLM located before and after the coronagraph focal plane mask, respectively. The simulation result has constrained the specification for phase accuracy of SLM in above two optical configurations. Finally, we have demonstrated that the S...

  12. Hard magnetization direction and its relation with magnetic permeability of highly grain-oriented electrical steel

    Institute of Scientific and Technical Information of China (English)

    Hao Wang; Chang-sheng Li; Tao Zhu

    2014-01-01

    The magnetic properties of highly grain-oriented electrical steel vary along different directions. In order to investigate these prop-erties, standard Epstein samples were cut at different angles to the rolling direction. The hard magnetization direction was found at an angle of 60° to the rolling direction. To compare the measured and fitting curves, when the magnetic field intensity is higher than 7000 A/m, it is appropriate to simulate the relation of magnetic permeability and magnetization angle using the conventional elliptical model. When the magnetic field intensity is less than 3000 A/m, parabolic fitting models should be used; but when the magnetic field intensity is between 3000 and 7000 A/m, hybrid models with high accuracy, as proposed in this paper, should be applied. Piecewise relation models of magnetic per-meability and magnetization angle are significant for improving the accuracy of electromagnetic engineering calculations of electrical steel, and these new models could be applied in further industrial applications.

  13. Highly sensitive detection of protein biomarkers via nuclear magnetic resonance biosensor with magnetically engineered nanoferrite particles.

    Science.gov (United States)

    Jeun, Minhong; Park, Sungwook; Lee, Hakho; Lee, Kwan Hyi

    Magnetic-based biosensors are attractive for on-site detection of biomarkers due to the low magnetic susceptibility of biological samples. Here, we report a highly sensitive magnetic-based biosensing system that is composed of a miniaturized nuclear magnetic resonance (NMR) device and magnetically engineered nanoferrite particles (NFPs). The sensing performance, also identified as the transverse relaxation (R2) rate, of the NMR device is directly related to the magnetic properties of the NFPs. Therefore, we developed magnetically engineered NFPs (MnMg-NFP) and used them as NMR agents to exhibit a significantly improved R2 rate. The magnetization of the MnMg-NFPs was increased by controlling the Mn and Mg cation concentration and distribution during the synthesis process. This modification of the Mn and Mg cation directly contributed to improving the R2 rate. The miniaturized NMR system, combined with the magnetically engineered MnMg-NFPs, successfully detected a small amount of infectious influenza A H1N1 nucleoprotein with high sensitivity and stability.

  14. Warmer and wetter winters: characteristics and implications of an extreme weather event in the High Arctic

    Science.gov (United States)

    Hansen, Brage B.; Isaksen, Ketil; Benestad, Rasmus E.; Kohler, Jack; Pedersen, Åshild Ø.; Loe, Leif E.; Coulson, Stephen J.; Larsen, Jan Otto; Varpe, Øystein

    2014-11-01

    One predicted consequence of global warming is an increased frequency of extreme weather events, such as heat waves, droughts, or heavy rainfalls. In parts of the Arctic, extreme warm spells and heavy rain-on-snow (ROS) events in winter are already more frequent. How these weather events impact snow-pack and permafrost characteristics is rarely documented empirically, and the implications for wildlife and society are hence far from understood. Here we characterize and document the effects of an extreme warm spell and ROS event that occurred in High Arctic Svalbard in January-February 2012, during the polar night. In this normally cold semi-desert environment, we recorded above-zero temperatures (up to 7 °C) across the entire archipelago and record-breaking precipitation, with up to 98 mm rainfall in one day (return period of >500 years prior to this event) and 272 mm over the two-week long warm spell. These precipitation amounts are equivalent to 25 and 70% respectively of the mean annual total precipitation. The extreme event caused significant increase in permafrost temperatures down to at least 5 m depth, induced slush avalanches with resultant damage to infrastructure, and left a significant ground-ice cover (˜5-20 cm thick basal ice). The ground-ice not only affected inhabitants by closing roads and airports as well as reducing mobility and thereby tourism income, but it also led to high starvation-induced mortality in all monitored populations of the wild reindeer by blocking access to the winter food source. Based on empirical-statistical downscaling of global climate models run under the moderate RCP4.5 emission scenario, we predict strong future warming with average mid-winter temperatures even approaching 0 °C, suggesting increased frequency of ROS. This will have far-reaching implications for Arctic ecosystems and societies through the changes in snow-pack and permafrost properties.

  15. High performance magnetocaloric perovskites for magnetic refrigeration

    OpenAIRE

    Velázquez, David

    2012-01-01

    We have applied mixed valance manganite perovskites as magnetocaloric materials in a magnetic refrigeration device. Relying on exact control of the composition and a technique to process the materials into single adjoined pieces, we have observed temperature spans above 9 K with two materials. Reasonable correspondence is found between experiments and a 2D numerical model, using the measured magnetocaloric properties of the two materials as input. © 2012 American Institute of Physics.

  16. Anomalous magnetic behaviour of NdCu 2 in high magnetic fields

    Science.gov (United States)

    Doerr, M.; Kramp, S.; Loewenhaupt, M.; Rotter, M.; Kratz, R.; Krug, H.; Eckert, D.; Siegel, H.; Verges, P.

    2001-01-01

    Some of the RCu 2 compounds (R=Ce,Pr,Tb,Dy) with easy a-axis show an irreversible change of the easy axis into the c-direction in high magnetic fields. This metamagnetic “axis conversion” is caused by a strong magneto-elastic coupling in the ac-plane. With NdCu 2 a similar magnetic behaviour was found for the first time in a system with an easy axis perpendicular to the ac-plane. We present results of magnetization in static magnetic fields up to 14 T. The minimum conversion field is μ0Hcrit=12.5 T which is higher than in the other compounds. At low temperatures the magnetic axis conversion coincides with the transition into the induced ferromagnetic state. Magnetization measurements were also carried out in pulsed fields up to 50 T. They show an almost linear increase of the conversion fields with temperature which gives a strong evidence that the conversion is caused by an effective quadrupolar coupling. In addition, comparing the results of static and pulsed field experiments, an influence of field duration on the conversion process was found. The high-precision pulsed field magnetization experiments were done in the Dresden high magnetic field facility (HLD).

  17. Extremely low-frequency magnetic fields and risk of childhood leukemia: A risk assessment by the ARIMMORA consortium.

    Science.gov (United States)

    Schüz, Joachim; Dasenbrock, Clemens; Ravazzani, Paolo; Röösli, Martin; Schär, Primo; Bounds, Patricia L; Erdmann, Friederike; Borkhardt, Arndt; Cobaleda, César; Fedrowitz, Maren; Hamnerius, Yngve; Sanchez-Garcia, Isidro; Seger, Rony; Schmiegelow, Kjeld; Ziegelberger, Gunde; Capstick, Myles; Manser, Melissa; Müller, Meike; Schmid, Christoph D; Schürmann, David; Struchen, Benjamin; Kuster, Niels

    2016-03-15

    Exposure to extremely low-frequency magnetic fields (ELF-MF) was evaluated in an International Agency for Research on Cancer (IARC) Monographs as "possibly carcinogenic to humans" in 2001, based on increased childhood leukemia risk observed in epidemiological studies. We conducted a hazard assessment using available scientific evidence published before March 2015, with inclusion of new research findings from the Advanced Research on Interaction Mechanisms of electroMagnetic exposures with Organisms for Risk Assessment (ARIMMORA) project. The IARC Monograph evaluation scheme was applied to hazard identification. In ARIMMORA for the first time, a transgenic mouse model was used to mimic the most common childhood leukemia: new pathogenic mechanisms were indicated, but more data are needed to draw definitive conclusions. Although experiments in different animal strains showed exposure-related decreases of CD8+ T-cells, a role in carcinogenesis must be further established. No direct damage of DNA by exposure was observed. Overall in the literature, there is limited evidence of carcinogenicity in humans and inadequate evidence of carcinogenicity in experimental animals, with only weak supporting evidence from mechanistic studies. New exposure data from ARIMMORA confirmed that if the association is nevertheless causal, up to 2% of childhood leukemias in Europe, as previously estimated, may be attributable to ELF-MF. In summary, ARIMMORA concludes that the relationship between ELF-MF and childhood leukemia remains consistent with possible carcinogenicity in humans. While this scientific uncertainty is dissatisfactory for science and public health, new mechanistic insight from ARIMMORA experiments points to future research that could provide a step-change in future assessments. Bioelectromagnetics. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. MAGNETIC FIELDS IN HIGH-MASS INFRARED DARK CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Pillai, T.; Kauffmann, J. [California Institute of Technology, Cahill Center for Astronomy and Astrophysics, Pasadena, CA 91125 (United States); Tan, J. C. [University of Florida, Gainesville, FL 32611 (United States); Goldsmith, P. F. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Carey, S. J. [Spitzer Science Center, California Institute of Technology, 1200 East California Boulevard, MC 314-6, Pasadena, CA 91125 (United States); Menten, K. M., E-mail: tpillai.astro@gmail.com [Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)

    2015-01-20

    High-mass stars are cosmic engines known to dominate the energetics in the Milky Way and other galaxies. However, their formation is still not well understood. Massive, cold, dense clouds, often appearing as infrared dark clouds (IRDCs), are the nurseries of massive stars. No measurements of magnetic fields in IRDCs in a state prior to the onset of high-mass star formation (HMSF) have previously been available, and prevailing HMSF theories do not consider strong magnetic fields. Here, we report observations of magnetic fields in two of the most massive IRDCs in the Milky Way. We show that IRDCs G11.11–0.12 and G0.253+0.016 are strongly magnetized and that the strong magnetic field is as important as turbulence and gravity for HMSF. The main dense filament in G11.11–0.12 is perpendicular to the magnetic field, while the lower density filament merging onto the main filament is parallel to the magnetic field. The implied magnetic field is strong enough to suppress fragmentation sufficiently to allow HMSF. Other mechanisms reducing fragmentation, such as the entrapment of heating from young stars via high-mass surface densities, are not required to facilitate HMSF.

  19. Lower Extremity Function following Partial Calcanectomy in High-Risk Limb Salvage Patients

    Directory of Open Access Journals (Sweden)

    Noah G. Oliver

    2015-01-01

    Full Text Available Partial calcanectomy (PC is an established limb salvage procedure for treatment of deep heel ulceration with concomitant calcaneal osteomyelitis. The purpose of this study is to determine if a relationship exists between the amount of calcaneus removed during PC and the resulting lower extremity function and limb salvage outcomes. Consecutive PC patients were retrospectively divided into two cohorts defined by the amount of calcaneus resected before wound closure: patients in cohort 1 retained = 50% of calcaneus, while patients in cohort 2 underwent resection of >50% of the calcaneus. The Lower Extremity Function Scale (LEFS was used to assess postoperative lower extremity function. The average amount of calcaneus resected was 13% ± 9.2 (1–39% and 74% ± 19.5 (51–100 in cohorts 1 and 2, respectively (P<0.0001. Below knee amputation was performed in 7 (28% and 5 (29% of subjects in cohorts 1 and 2, respectively (P=1.0. The average LEFS score was 33.9 ± 15.0 for subjects in cohort 1 and 36.2 ± 19.9 for the subjects cohort 2 (P=0.8257 which correlates to “moderate to quite a bit of difficulty.” Our study suggests that regardless of the amount of calcaneus resected, PC provides a viable treatment option for high-risk patients with calcaneal osteomyelitis.

  20. Performance of High Temperature Operational Amplifier, Type LM2904WH, under Extreme Temperatures

    Science.gov (United States)

    Patterson, Richard; Hammoud, Ahmad; Elbuluk, Malik

    2008-01-01

    Operation of electronic parts and circuits under extreme temperatures is anticipated in NASA space exploration missions as well as terrestrial applications. Exposure of electronics to extreme temperatures and wide-range thermal swings greatly affects their performance via induced changes in the semiconductor material properties, packaging and interconnects, or due to incompatibility issues between interfaces that result from thermal expansion/contraction mismatch. Electronics that are designed to withstand operation and perform efficiently in extreme temperatures would mitigate risks for failure due to thermal stresses and, therefore, improve system reliability. In addition, they contribute to reducing system size and weight, simplifying its design, and reducing development cost through the elimination of otherwise required thermal control elements for proper ambient operation. A large DC voltage gain (100 dB) operational amplifier with a maximum junction temperature of 150 C was recently introduced by STMicroelectronics [1]. This LM2904WH chip comes in a plastic package and is designed specifically for automotive and industrial control systems. It operates from a single power supply over a wide range of voltages, and it consists of two independent, high gain, internally frequency compensated operational amplifiers. Table I shows some of the device manufacturer s specifications.

  1. Probing deep photospheric layers of the quiet Sun with high magnetic sensitivity

    Science.gov (United States)

    Lagg, A.; Solanki, S. K.; Doerr, H.-P.; Martínez González, M. J.; Riethmüller, T.; Collados Vera, M.; Schlichenmaier, R.; Orozco Suárez, D.; Franz, M.; Feller, A.; Kuckein, C.; Schmidt, W.; Asensio Ramos, A.; Pastor Yabar, A.; von der Lühe, O.; Denker, C.; Balthasar, H.; Volkmer, R.; Staude, J.; Hofmann, A.; Strassmeier, K.; Kneer, F.; Waldmann, T.; Borrero, J. M.; Sobotka, M.; Verma, M.; Louis, R. E.; Rezaei, R.; Soltau, D.; Berkefeld, T.; Sigwarth, M.; Schmidt, D.; Kiess, C.; Nicklas, H.

    2016-11-01

    Context. Investigations of the magnetism of the quiet Sun are hindered by extremely weak polarization signals in Fraunhofer spectral lines. Photon noise, straylight, and the systematically different sensitivity of the Zeeman effect to longitudinal and transversal magnetic fields result in controversial results in terms of the strength and angular distribution of the magnetic field vector. Aims: The information content of Stokes measurements close to the diffraction limit of the 1.5 m GREGOR telescope is analyzed. We took the effects of spatial straylight and photon noise into account. Methods: Highly sensitive full Stokes measurements of a quiet-Sun region at disk center in the deep photospheric Fe i lines in the 1.56 μm region were obtained with the infrared spectropolarimeter GRIS at the GREGOR telescope. Noise statistics and Stokes V asymmetries were analyzed and compared to a similar data set of the Hinode spectropolarimeter (SOT/SP). Simple diagnostics based directly on the shape and strength of the profiles were applied to the GRIS data. We made use of the magnetic line ratio technique, which was tested against realistic magneto-hydrodynamic simulations (MURaM). Results: About 80% of the GRIS spectra of a very quiet solar region show polarimetric signals above a 3σ level. Area and amplitude asymmetries agree well with small-scale surface dynamo-magneto hydrodynamic simulations. The magnetic line ratio analysis reveals ubiquitous magnetic regions in the ten to hundred Gauss range with some concentrations of kilo-Gauss fields. Conclusions: The GRIS spectropolarimetric data at a spatial resolution of ≈0.̋4 are so far unique in the combination of high spatial resolution scans and high magnetic field sensitivity. Nevertheless, the unavoidable effect of spatial straylight and the resulting dilution of the weak Stokes profiles means that inversion techniques still bear a high risk of misinterpretating the data.

  2. A Stable, Extreme Temperature, High Radiation, Compact. Low Power Clock Oscillator for Space, Geothermal, Down-Hole & other High Reliability Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Efficient and stable clock signal generation requirements at extreme temperatures and high radiation are not met with the current solutions. Chronos Technology...

  3. Tuning magnetic disorder in diluted magnetic semiconductors using high fields to 89 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Crooker, Scott A [Los Alamos National Laboratory; Samarth, Nitin [PENN STATE U

    2008-01-01

    We describe recent and ongoing studies at the National High Magnetic Field Laboratory at Los Alamos using the new '100 Tesla Multi-Shot Magnet', which is presently delivering fields up to {approx}89 T during its commissioning. We discuss the first experiments performed in this magnet system, wherein the linewidth of low-temperature photoluminescence spectra was used to directly reveal the degree of magnetic alloy disorder 'seen' by excitons in single Zn{sub 0.80}Cd{sub 0.22}Mn{sub 0.08}Se quantum wells. The magnetic potential landscape in II-VI diluted magnetic semiconductors (DMS) is typically smoothed when the embedded Mn{sup 2+} spins align in an applied field. However, an important (but heretofore untested) prediction of current models of compositional disorder is that magnetic alloy fluctuations in many DMS compounds should increase again in very large magnetic fields approaching 100 T. We observed precisely this increase above {approx}70 T, in agreement with a simple model of magnetic alloy disorder.

  4. Magnetic reconnection in high-energy-density plasmas in the presence of an external magnetic field

    Science.gov (United States)

    Fox, W.; Bhattacharjee, A.; Fiksel, G.; Nilson, P.; Hu, S.; Chang, P.-Y.; Barnak, D.; Betti, R.

    2012-10-01

    Magnetic reconnection has recently been observed and studied in high-energy-density, laser-produced plasmas. These experiments are interesting both for obtaining fundamental data on reconnection, and may also be relevant for inertial fusion, as this magnetic reconnection geometry, with multiple, colliding, magnetized plasma bubbles, occurs naturally inside ICF hohlraums. We present initial results of experiments conducted on the OMEGA EP facility on magnetic reconnection between colliding, magnetized blowoff plasmas. While in previous experiments the magnetic fields were self-generated in the plasma by the Biermann battery effect, in these experiments the seed magnetic field is generated by pulsing current through a pair of external foils using the MIFEDS current generator (Magneto-Inertial Fusion Electrical Discharge System) developed at LLE. Time-resolved images of the magnetic fields and plasma dynamics are obtained from proton radiography and x-ray self-emission, respectively. We present initial results of the experiments, including comparison to ``null'' experiments with zero MIFEDS magnetic field, and associated modeling using the radiation-hydro code DRACO and the particle-in-cell code PSC.

  5. Survey of Processing Methods for High Strength High Conductivity Wires for High Field Magnet Applications

    Energy Technology Data Exchange (ETDEWEB)

    Han, K.; Embury, J.D.

    1998-10-01

    This paper will deal with the basic concepts of attaining combination of high strength and high conductivity in pure materials, in-situ composites and macrocomposites. It will survey current attainments, and outline where some future developments may lie in developing wire products that are close to the theoretical strength of future magnet applications.

  6. High magnetic field pulsars and magnetars a unified picture

    CERN Document Server

    Zhang, B; Zhang, Bing; Harding, Alice K.

    2000-01-01

    We propose a unified picture of high magnetic field radio pulsars and magnetars by arguing that they are all rotating high-field neutron stars, but have different orientations of their magnetic axes with respective to their rotation axes. In strong magnetic fields where photon splitting suppresses pair creation near the surface, the high-field pulsars can have active inner accelerators while the anomalous X-ray pulsars cannot. This can account for the very different observed emission characteristics of the anomalous X-ray pulsar 1E 2259+586 and the high field radio pulsar PSR J1814-1744. A predicted consequence of this picture is that radio pulsars having surface magnetic field greater than about $2\\times 10^{14}$ G should not exist.

  7. Inorganic Nanostructured High-Temperature Magnet Wires Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop a high-temperature tolerant electrically-insulating coating for magnet wires. The Phase I program will result in a flexible, inorganic...

  8. Radiation Shielding Utilizing A High Temperature Superconducting Magnet Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project aims to leverage near-term high-temperature superconducting technologies to assess applicability of magnetic shielding for protecting against exposure...

  9. Oxidative effects of extremely low frequency magnetic field and radio frequency radiation on testes tissues of diabetic and healthy rats.

    Science.gov (United States)

    Kuzay, D; Ozer, C; Sirav, B; Canseven, A G; Seyhan, N

    2017-01-01

    With the development of technology, people are increasingly under the exposure of electromagnetic fields. Individuals with chronic diseases such as diabetes are now long-term exposed to Radio Frequency-RF radiation and extremely low frequency (ELF) magnetic fields (MFs). The purpose of this present study is to investigate oxidative effects and antioxidant parameters of ELF MFs and RF radiation on testis tissue in diabetic and healthy rats. Wistar male rats were divided into 10 groups. Intraperitoneal single dose STZ (65 mg/kg) dissolved in citrate buffer (0.1M (pH 4.5)) was injected to diabetes groups. ELF MFs and RF radiation were used as an electromagnetic exposure for 20 min/day, 5 days/week for one month. Testis tissue oxidant malondialdehyde (MDA), and antioxidants glutathione (GSH), and total nitric oxide (NOx) levels were determined. The results of ANOVA and Mann-Whitney tests were compared; p radiation resulted in an increase in testicular tissue MDA and NOX levels (p radiation practices increased the oxidative stress in testis tissue while causing a decrease in antioxidant level which was more distinctive in diabetic rats (Tab. 1, Fig. 3, Ref. 30).

  10. Fabrication of surfaces with extremely high contact angle hysteresis from polyelectrolyte multilayer.

    Science.gov (United States)

    Wang, Liming; Wei, Jingjing; Su, Zhaohui

    2011-12-20

    High contact angle hysteresis on polyelectrolyte multilayers (PEMs) ion-paired with hydrophobic perfluorooctanoate anions is reported. Both the bilayer number of PEMs and the ionic strength of deposition solutions have significant influence on contact angle hysteresis: higher ionic strength and greater bilayer number cause increased contact angle hysteresis values. The hysteresis values of ~100° were observed on smooth PEMs and pinning of the receding contact line on hydrophilic defects is implicated as the cause of hysteresis. Surface roughness can be used to further tune the contact angle hysteresis on the PEMs. A surface with extremely high contact angle hysteresis of 156° was fabricated when a PEM was deposited on a rough substrate coated with submicrometer scale silica spheres. It was demonstrated that this extremely high value of contact angle hysteresis resulted from the penetration of water into the rough asperities on the substrate. The same substrate hydrophobized by chemical vapor deposition of 1H,1H,2H,2H-perfluorooctyltriethoxysilane exhibits high advancing contact angle and low hysteresis.

  11. Magnetic properties of sintered high energy sm-co and nd-fe-b magnets

    Directory of Open Access Journals (Sweden)

    Talijan Nadežda M.

    2006-01-01

    Full Text Available Magnetic properties of permanent magnetic materials based on intermetallic compounds of Sm-Co and Nd-Fe-B are in direct dependence on the microstructure. In the first part of this paper, having in mind the importance of the regime of sintering and heat treatment to obtain the optimal magnetic structure, yet another approach in defining the most adequate technological parameters of the sintering process for applied heat treatment conditions was made. The goal of these investigations was to use the correlation that exists between sintering conditions (temperature and time and intensity of the diffraction peak of the (111 plane of the SmCo5 phase to optimize. In the second part a brief overview of high energy magnetic materials based on Nd-Fe-B is presented with special emphasis to the current research and development of high remanent nanocomposite magnetic materials based on Nd-Fe-B alloys with a reduced Nd content. Part of experimental results gained during research of the sintering process of SmCo5 magnetic materials were realized and published earlier. The scientific meeting devoted to the 60th anniversary of Frankel’s theory of sintering was an opportunity to show once more the importance and role of sintering in optimization of the magnetic microstructure of sintered Sm Co5 magnetic materials.

  12. Makeup and uses of a basic magnet laboratory for characterizing high-temperature permanent magnets

    Science.gov (United States)

    Niedra, Janis M.; Schwarze, Gene E.

    1991-01-01

    A set of instrumentation for making basic magnetic measurements was assembled in order to characterize high intrinsic coercivity, rare earth permanent magnets with respect to short term demagnetization resistance and long term aging at temperatures up to 300 C. The major specialized components of this set consist of a 13 T peak field, capacitor discharge pulse magnetizer; a 10 in. pole size, variable gap electromagnet; a temperature controlled oven equipped with iron cobalt pole piece extensions and a removable paddle that carries the magnetization and field sensing coils; associated electronic integrators; and sensor standards for field intensity H and magnetic moment M calibration. A 1 cm cubic magnet sample, carried by the paddle, fits snugly between the pole piece extensions within the electrically heated aluminum oven, where fields up to 3.2 T can be applied by the electromagnet at temperatures up to 300 C. A sample set of demagnetization data for the high energy Sm2Co17 type of magnet is given for temperatures up to 300 C. These data are reduced to the temperature dependence of the M-H knee field and of the field for a given magnetic induction swing, and they are interpreted to show the limits of safe operation.

  13. Conceptual Design of the 45 T Hybrid Magnet at the Nijmegen High Field Magnet Laboratory

    CERN Document Server

    Wiegers, SAJ; Bird, M D; Rook, J; Perenboom, J A A J; Wiegers, S A J; Bonito-Oliva, A; den Ouden, A

    2010-01-01

    A 45 T Hybrid Magnet System is being developed at the Nijmegen High Field Magnet Laboratory as part of the Nijmegen Center for Advanced Spectroscopy. The 45 T Hybrid Magnet System will be used in combination with far-infra-red light produced by a Free Electron Laser under construction directly adjacent to the High Field Magnet Laboratory. The superconducting outsert magnet will consist of three CICC coils wound on a single coil form, using Nb3Sn strands. A test program for strand and cable qualification is underway. The CICC will carry 13 kA and the coils will produce 12 T on axis field in a 600 mm warm bore. The nominal operating temperature will be 4.5 K maintained with forced-flow supercritical helium. The insert magnet will produce 33 T at 40 kA in a 32 mm bore consuming 20 MW, and will consist of four coils. The insert magnet will be galvanically and mechanically isolated from the outsert magnet. Complete system availability for users is expected in 2014. In this paper we will report on the conceptual de...

  14. High-temperature molecular magnets based on cyanovanadate building blocks: spontaneous magnetization at 230 k.

    Science.gov (United States)

    Entley, W R; Girolami, G S

    1995-04-21

    The molecular-based magnetic materials Cs(2)Mn(||)[V(||)(CN)(6)] (1) and (Et(4)N)(0.5)Mn(l.25)- [V(CN)(5)].2H(2)O (2) (where Et is ethyl) were prepared by the addition of manganese(II) triflate to aqueous solutions of the hexacyanovanadate(II) ion at 0 degrees C. Whereas 1 crystallizes in a face-centered cubic lattice, 2 crystallizes in a noncubic space group. The cesium salt (1) has features characteristic of a three-dimensional ferrimagnet with a Néel transition at 125 kelvin. The tetraethylammonium salt (2) also behaves as a three-dimensional ferrimagnet with a Néel temperature of 230 kelvin; only two other molecular magnets have higher magnetic ordering temperatures. Saturation magnetization measurements indicate that in both compounds the V(II) and high-spin Mn(II) centers are antiferromagnetically coupled. Both 1 and 2 exhibit hysteresis loops characteristic of soft magnets below their magnetic phase-transition temperatures. The high magnetic ordering temperatures of these cyano-bridged solids confirm that the incorporation of early transition elements into the lattice promotes stronger magnetic coupling by enhancing the backbonding into the cyanide pi* orbitals.

  15. Study of HTS Wires at High Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Turrioni, D.; Barzi, E.; Lamm, M.J.; Yamada, R.; Zlobin, A.V.; Kikuchi, A.; /Fermilab

    2009-01-01

    Fermilab is working on the development of high field magnet systems for ionization cooling of muon beams. The use of high temperature superconducting (HTS) materials is being considered for these magnets using Helium refrigeration. Critical current (I{sub c}) measurements of HTS conductors were performed at FNAL and at NIMS up to 28 T under magnetic fields at zero to 90 degree with respect to the sample face. A description of the test setups and results on a BSCCO-2223 tape and second generation (2G) coated conductors are presented.

  16. Magnetic Fields in High-Mass Infrared Dark Clouds

    CERN Document Server

    Pillai, Thushara; Tan, Jonathan; Goldsmith, Paul; Carey, Sean; Menten, Karl

    2014-01-01

    High-mass Stars are cosmic engines known to dominate the energetics in the Milky Way and other galaxies. However, their formation is still not well understood. Massive, cold, dense clouds, often appearing as Infrared Dark Clouds (IRDCs), are the nurseries of massive stars. No measurements of magnetic fields in IRDCs in a state prior to the onset of high-mass star formation (HMSF) have previously been available, and prevailing HMSF theories do not consider strong magnetic fields. Here, we report observations of magnetic fields in two of the most massive IRDCs in the Milky Way. We show that IRDCs G11.11-0.12 and G0.253+0.016 are strongly magnetized and that the strong magnetic field is as important as turbulence and gravity for HMSF. The main dense filament in G11.11-0.12 is perpendicular to the magnetic field, while the lower density filament merging onto the main filament is parallel to the magnetic field. The implied magnetic field is strong enough to suppress fragmentation sufficiently to allow HMSF. Other ...

  17. In situ observation and measurement of composites subjected to extremely high temperature

    Science.gov (United States)

    Fang, Xufei; Yu, Helong; Zhang, Guobing; Su, Hengqiang; Tang, Hongxiang; Feng, Xue

    2014-03-01

    In this work, we develop an instrument to study the ablation and oxidation process of materials such as C/SiC (carbon fiber reinforced silicon carbide composites) and ultra-high temperature ceramic in extremely high temperature environment. The instrument is integrated with high speed cameras with filtering lens, infrared thermometers and water vapor generator for image capture, temperature measurement, and humid atmosphere, respectively. The ablation process and thermal shock as well as the temperature on both sides of the specimen can be in situ monitored. The results show clearly the dynamic ablation and liquid oxide flowing. In addition, we develop an algorithm for the post-processing of the captured images to obtain the deformation of the specimens, in order to better understand the behavior of the specimen subjected to high temperature.

  18. Foundations of high-energy-density physics physical processes of matter at extreme conditions

    CERN Document Server

    Larsen, Jon

    2017-01-01

    High-energy-density physics explores the dynamics of matter at extreme conditions. This encompasses temperatures and densities far greater than we experience on Earth. It applies to normal stars, exploding stars, active galaxies, and planetary interiors. High-energy-density matter is found on Earth in the explosion of nuclear weapons and in laboratories with high-powered lasers or pulsed-power machines. The physics explored in this book is the basis for large-scale simulation codes needed to interpret experimental results whether from astrophysical observations or laboratory-scale experiments. The key elements of high-energy-density physics covered are gas dynamics, ionization, thermal energy transport, and radiation transfer, intense electromagnetic waves, and their dynamical coupling. Implicit in this is a fundamental understanding of hydrodynamics, plasma physics, atomic physics, quantum mechanics, and electromagnetic theory. Beginning with a summary of the topics and exploring the major ones in depth, thi...

  19. Poly(acrylamide-MWNTs hybrid hydrogel with extremely high mechanical strength

    Directory of Open Access Journals (Sweden)

    Feng Huanhuan

    2016-01-01

    Full Text Available Poly(acrylamide-multiwalled carbon nanotubes (PAAm-MWNTs hybrid hydrogels were prepared through the radiation-induced polymerization and crosslinking of the aqueous solution of acrylamide and well-dispersed MWNTs for the first time. The PAAm gels obtained by the radiation-induced polymerization and cosslinking showed very high mechanical strengths, and the PAAm-MWNTs hybrid hydrogels had improved mechanical properties compared with the PAAm gels, and hence the PAAm-MWNTs hybrid hydrogels showed extremely high compressive and tensile strengths. The hybrid hydrogels with water contents more than 80 wt.% usually did not fracture even at compressive strengths close to or even more than 60 MPa and strains more than 97%. And the hybrid hydrogels had very high elongations (more than 2000% in some cases, especially when the water content was high. The tensile strengths were in sub-MPa. The hybrid PAAm-MWNTs hydrogel is one of the strongest hydrogel even made.

  20. Table-Top Milliwatt-Class Extreme Ultraviolet High Harmonic Light Source

    CERN Document Server

    Klas, Robert; Tschernajew, Maxim; Hädrich, Steffen; Shamir, Yariv; Tünnermann, Andreas; Rothhardt, Jan; Limpert, Jens

    2016-01-01

    Extreme ultraviolet (XUV) lasers are essential for the investigation of fundamental physics. Especially high repetition rate, high photon flux sources are of major interest for reducing acquisition times and improving signal to noise ratios in a plethora of applications. Here, an XUV source based on cascaded frequency conversion is presented, which delivers due to the drastic better single atom response for short wavelength drivers, an average output power of (832 +- 204) {\\mu}W at 21.7 eV. This is the highest average power produced by any HHG source in this spectral range surpassing precious demonstrations by more than a factor of four. Furthermore, a narrow-band harmonic at 26.6 eV with a relative energy bandwidth of only {\\Delta}E/E= 1.8 x 10E-3 has been generated, which is of high interest for high precision spectroscopy experiments.

  1. EEE - Extreme Energy Events: an astroparticle physics experiment in Italian High Schools

    Science.gov (United States)

    Abbrescia, M.; Avanzini, C.; Baldini, L.; Baldini Ferroli, R.; Batignani, G.; Bencivenni, G.; Bossini, E.; Bressan, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccia, E.; Corvaglia, A.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D'Incecco, M.; Dreucci, M.; Fabbri, F. L.; Fattibene, E.; Ferrarov, A.; Forster, R.; Frolov, V.; Galeotti, P.; Garbini, M.; Gemme, G.; Gnesi, I.; Grazzi, S.; Gustavino, C.; Hatzifotiadou, D.; La Rocca, P.; Maggiora, A.; Maron, G.; Mazziotta, M. N.; Miozzi, S.; Noferini, F.; Nozzoli, F.; Panareo, M.; Panetta, M. P.; Paoletti, R.; Perasso, L.; Pilo, F.; Piragino, G.; Riggi, F.; Righini, G. C.; Rodriguez Rodriguez, A.; Sartorelli, G.; Scapparone, E.; Schioppa, M.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Squarcia, S.; Taiuti, M.; Terreni, G.; Vistoli, M. C.; Votano, L.; Williams, M. C. S.; Zani, S.; Zichichi, A.; Zuyeuski, R.

    2016-05-01

    The Extreme Energy Events project (EEE) is aimed to study Extensive Air Showers (EAS) from primary cosmic rays of more than 1018 eV energy detecting the ground secondary muon component using an array of telescopes with high spatial and time resolution. The second goal of the EEE project is to involve High School teachers and students in this advanced research work and to initiate them in scientific culture: to reach both purposes the telescopes are located inside High School buildings and the detector construction, assembling and monitoring - together with data taking and analysis - are done by researchers from scientific institutions in close collaboration with them. At present there are 42 telescopes in just as many High Schools scattered all over Italy, islands included, plus two at CERN and three in INFN units. We report here some preliminary physics results from the first two common data taking periods together with the outreach impact of the project.

  2. Image-based motion compensation for high-resolution extremities cone-beam CT

    Science.gov (United States)

    Sisniega, A.; Stayman, J. W.; Cao, Q.; Yorkston, J.; Siewerdsen, J. H.; Zbijewski, W.

    2016-03-01

    Purpose: Cone-beam CT (CBCT) of the extremities provides high spatial resolution, but its quantitative accuracy may be challenged by involuntary sub-mm patient motion that cannot be eliminated with simple means of external immobilization. We investigate a two-step iterative motion compensation based on a multi-component metric of image sharpness. Methods: Motion is considered with respect to locally rigid motion within a particular region of interest, and the method supports application to multiple locally rigid regions. Motion is estimated by maximizing a cost function with three components: a gradient metric encouraging image sharpness, an entropy term that favors high contrast and penalizes streaks, and a penalty term encouraging smooth motion. Motion compensation involved initial coarse estimation of gross motion followed by estimation of fine-scale displacements using high resolution reconstructions. The method was evaluated in simulations with synthetic motion (1-4 mm) applied to a wrist volume obtained on a CMOS-based CBCT testbench. Structural similarity index (SSIM) quantified the agreement between motion-compensated and static data. The algorithm was also tested on a motion contaminated patient scan from dedicated extremities CBCT. Results: Excellent correction was achieved for the investigated range of displacements, indicated by good visual agreement with the static data. 10-15% improvement in SSIM was attained for 2-4 mm motions. The compensation was robust against increasing motion (4% decrease in SSIM across the investigated range, compared to 14% with no compensation). Consistent performance was achieved across a range of noise levels. Significant mitigation of artifacts was shown in patient data. Conclusion: The results indicate feasibility of image-based motion correction in extremities CBCT without the need for a priori motion models, external trackers, or fiducials.

  3. High yield simultaneous hydrogen and ethanol production under extreme-thermophilic (70 C) mixed culture environment

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chenxi [Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China); Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby (Denmark); O-Thong, Sompong [Department of Biology, Faculty of Science, Thaksin University, Patthalung 93110 (Thailand); Karakashev, Dimitar; Angelidaki, Irini [Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby (Denmark); Lu, Wenjing; Wang, Hongtao [Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2009-07-15

    The effect of pH and medium composition on extreme-thermophilic (70 C) dark fermentative simultaneous hydrogen and ethanol production (process performance and microbial ecology) was investigated. Hydrogen and ethanol yields were optimized with respect to glucose, peptone, FeSO{sub 4}, NaHCO{sub 3}, yeast extract, trace mineral salts, vitamins, and phosphate buffer concentrations as well as initial pH as independent variables. A combination of low levels of both glucose ({<=}2 g/L) and vitamin solutions ({<=}1 mL/L) and high levels of initial pH ({>=}7), mineral salts solution ({>=}5 mL/L) and FeSO{sub 4} ({>=}100 mg/L) stimulated the hydrogen production, while high level of glucose ({>=}5 g/L) and low levels of both initial pH ({<=}5.5) and mineral salts solution ({<=}1 mL/L) enhanced the ethanol production. High yield of simultaneous hydrogen and ethanol production (1.58 mol H{sub 2}/mol glucose combined with an ethanol yield of 0.90 mol ethanol/mol glucose) was achieved under extreme-thermophilic mixed culture environment. Results obtained showed that the shift of the metabolic pathways favouring either hydrogen or ethanol production was affected by the change in cultivation conditions (pH and medium composition). The mixed culture in this study demonstrated flexible ability for simultaneous hydrogen and ethanol production, depending on pH and nutrients formulation. The microorganisms involved could be regarded as simultaneous hydrogen/ethanol producers, as hydrogen and ethanol fermentation under all conditions was carried out by a group of extreme-thermophilic bacterial species related to Thermoanaerobacter, Thermoanaerobacterium and Caldanaerobacter. (author)

  4. Magnetic Refrigeration Technology for High Efficiency Air Conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Boeder, A; Zimm, C

    2006-09-30

    Magnetic refrigeration was investigated as an efficient, environmentally friendly, flexible alternative to conventional residential vapor compression central air conditioning systems. Finite element analysis (FEA) models of advanced geometry active magnetic regenerator (AMR) beds were developed to minimize bed size and thus magnet mass by optimizing geometry for fluid flow and heat transfer and other losses. Conventional and magnetocaloric material (MCM) regenerator fabrication and assembly techniques were developed and advanced geometry passive regenerators were built and tested. A subscale engineering prototype (SEP) magnetic air conditioner was designed, constructed and tested. A model of the AMR cycle, combined with knowledge from passive regenerator experiments and FEA results, was used to design the regenerator beds. A 1.5 Tesla permanent magnet assembly was designed using FEA and the bed structure and plenum design was extensively optimized using FEA. The SEP is a flexible magnetic refrigeration platform, with individually instrumented beds and high flow rate and high frequency capability, although the current advanced regenerator geometry beds do not meet performance expectations, probably due to manufacturing and assembly tolerances. A model of the AMR cycle was used to optimize the design of a 3 ton capacity magnetic air conditioner, and the system design was iterated to minimize external parasitic losses such as heat exchanger pressure drop and fan power. The manufacturing cost for the entire air conditioning system was estimated, and while the estimated SEER efficiency is high, the magnetic air conditioning system is not cost competitive as currently configured. The 3 ton study results indicate that there are other applications where magnetic refrigeration is anticipated to have cost advantages over conventional systems, especially applications where magnetic refrigeration, through the use of its aqueous heat transfer fluid, could eliminate intermediate

  5. High performance magnet power supply optimization

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, L.T.

    1988-01-01

    The power supply system for the joint LBL--SLAC proposed accelerator PEP provides the opportunity to take a fresh look at the current techniques employed for controlling large amounts of dc power and the possibility of using a new one. A basic requirement of +- 100 ppM regulation is placed on the guide field of the bending magnets and quadrupoles placed around the 2200 meter circumference of the accelerator. The optimization questions to be answered by this paper are threefold: Can a firing circuit be designed to reduce the combined effects of the harmonics and line voltage combined effects of the harmonics and line voltage unbalance to less than 100 ppM in the magnet field. Given the ambiguity of the previous statement, is the addition of a transistor bank to a nominal SCR controlled system the way to go or should one opt for an SCR chopper system running at 1 KHz where multiple supplies are fed from one large dc bus and the cost--performance evaluation of the three possible systems.

  6. Spin dynamics in highly frustrated pyrochlore magnets

    Science.gov (United States)

    Petit, Sylvain; Guitteny, Solène; Robert, Julien; Bonville, Pierre; Decorse, Claudia; Ollivier, Jacques; Mutka, Hannu; Mirebeau, Isabelle

    2015-01-01

    This paper aims at showing the complementarity between time-of-flight and triple-axis neutron scattering experiments, on the basis of two topical examples in the field of geometrical magnetic frustration. Rare earth pyrochlore magnets R2Ti2O7 (R is a rare earth) play a prominent role in this field, as they form model systems showing a rich variety of ground states, depending on the balance between dipolar, exchange interactions and crystal field. We first review the case of the XY antiferromagnet Er2 Ti2 O7. Here a transition towards a Néel state is observed, possibly induced by an order-by-disorder mechanism. Effective exchange parameters can be extracted from S(Q,ω). We then examine the case of the spin liquid Tb2 Ti2 O7. Recent experiments reveal a complex ground state characterized by "pinch points" and supporting a low energy excitation. These studies demonstrate the existence of a coupling between crystal field transitions and a transverse acoustic phonon mode.

  7. Extremely high reflection of solar wind protons as neutral hydrogen atoms from regolith in space

    CERN Document Server

    Wieser, Martin; Futaana, Yoshifumi; Holmström, Mats; Bhardwaj, Anil; Sridharan, R; Dhanya, MB; Wurz, Peter; Schaufelberger, Audrey; Asamura, Kazushi; 10.1016/j.pss.2009.09.012

    2010-01-01

    We report on measurements of extremely high reflection rates of solar wind particles from regolith-covered lunar surfaces. Measurements by the Sub-keV Atom Reflecting Analyzer (SARA) instrument on the Indian Chandrayaan-1 spacecraft in orbit around the Moon show that up to 20% of the impinging solar wind protons are reflected from the lunar surface back to space as neutral hydrogen atoms. This finding, generally applicable to regolith-covered atmosphereless bodies, invalidates the widely accepted assumption that regolith almost completely absorbs the impinging solar wind.

  8. FURTHER EVIDENCE ON THE “COSTS OF PRIVILEGE”: PERFECTIONISM IN HIGH-ACHIEVING YOUTH AT SOCIOECONOMIC EXTREMES

    Science.gov (United States)

    LYMAN, EMILY L.; LUTHAR, SUNIYA S.

    2015-01-01

    This study involved two academically-gifted samples of 11th and 12th grade youth at the socioeconomic status (SES) extremes; one from an exclusive private, affluent school, and the other from a magnet school with low-income students. Negative and positive adjustment outcomes were examined in relation to multiple dimensions of perfectionism including perceived parental pressures to be perfect, personal perfectionistic self-presentation, and envy of peers. The low-income students showed some areas of relative vulnerability, but when large group differences were found, it was the affluent youth who were at a disadvantage, with substantially higher substance use and peer envy. Affluent girls seemed particularly vulnerable, with pronounced elevations in perfectionistic tendencies, peer envy, as well as body dissatisfaction. Examination of risk and protective processes showed that relationships with mothers were associated with students’ distress as well as positive adjustment. Additionally, findings showed links between (a) envy of peers and multiple outcomes (among high SES girls in particular), (b) dimensions of perfectionism in relation to internalizing symptoms, and (c) high extrinsic versus intrinsic values in relation to externalizing symptoms. PMID:26345229

  9. Improved Electrical Insulation of Rare Earth Permanent Magnetic Materials With High Magnetic Properties

    Institute of Scientific and Technical Information of China (English)

    CHANG Ying; WANG Da-peng; LI Wei; PAN Wei; YU Xiao-jun; QI Min

    2009-01-01

    Rare earth permanent magnetic materials are typical electrical conductor, and their magnetic properties will decrease because of the eddy current effect, so it is difficult to keep them stable for a long enough time under a high frequency AC field. In the present study, as far as rare earth permanent magnets are concerned, for the first time, rare earth permanent magnets with strong electrical insulation and high magnetic performance have been obtained through experiments, and their properties are as follows:(1) Sm2TM17: Br=0.62 T, jHc=803.7 kA/m, (BH)m= The magnetic properties of Sm2TM17 and NdFeB are obviously higher than those of ferrite permanent magnet, and the electric insulating characteristics of Sm2TM17 and NdFeB applied have in fact been approximately the same as those of ferrite. Therefore, Sm2TM17 and NdFeB will possess the ability to take the place of ferrite under a certain high frequency AC electric field.

  10. CLASH: Extreme Emission Line Galaxies and Their Implication on Selection of High-Redshift Galaxies

    CERN Document Server

    Huang, Xingxing; Wang, Junxian; Ford, Holland; Lemze, Doron; Moustakas, John; Shu, Xinwen; Van der Wel, Arjen; Zitrin, Adi; Frye, Brenda L; Postman, Marc; Bartelmann, Matthias; Benitez, Narciso; Bradley, Larry; Broadhurst, Tom; Coe, Dan; Donahue, Megan; Infante, Leopoldo; Kelson, Daniel; Koekemoer, Anton; Lahav, Ofer; Medezinski, Elinor; Moustakas, Leonidas; Rosati, Piero; Seitz, Stella; Umetsu, Keiichi

    2014-01-01

    We utilize the CLASH (Cluster Lensing And Supernova survey with Hubble) observations of 25 clusters to search for extreme emission-line galaxies (EELGs). The selections are carried out in two central bands: F105W (Y105) and F125W (J125), as the flux of the central bands could be enhanced by the presence of [O III] 4959, 5007 at redshift of about 0.93-1.14 and 1.57-1.79, respectively. The multi-band observations help to constrain the equivalent widths of emission lines. Thanks to cluster lensing, we are able to identify 52 candidates down to an intrinsic limiting magnitude of 28.5 and to a rest-frame [O III] 4959,5007 equivalent width of about 3737 angstrom. Our samples include a number of EELGs at lower luminosities that are missed in other surveys, and the extremely high equivalent width can be only found in such faint galaxies. These EELGs can mimic the dropout feature similar to that of high redshift galaxies and contaminate the color-color selection of high redshift galaxies when the S/N ratio is limited ...

  11. CLASH: EXTREME EMISSION-LINE GALAXIES AND THEIR IMPLICATION ON SELECTION OF HIGH-REDSHIFT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xingxing; Wang, Junxian; Shu, Xinwen [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zheng, Wei; Ford, Holland; Lemze, Doron [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Moustakas, John [Department of Physics and Astronomy, Siena College, 515 Loudon Road, Loudonville, NY 12211 (United States); Van der Wel, Arjen [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg (Germany); Zitrin, Adi [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Frye, Brenda L. [Steward Observatory/Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Postman, Marc; Bradley, Larry; Coe, Dan [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21208 (United States); Bartelmann, Matthias [Leiden Observatory, Leiden University, P. O. Box 9513, 2300 RA Leiden (Netherlands); Benítez, Narciso [Instituto de Astrofísica de Andalucía (CSIC), C/Camino Bajo de Huétor 24, Granada E-18008 (Spain); Broadhurst, Tom [Department of Theoretical Physics, University of Basque Country UPV/EHU E-Bilbao (Spain); Donahue, Megan [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Infante, Leopoldo, E-mail: hxx@mail.ustc.edu.cn [Departamento de Astronoía y Astrofísica, Pontificia Universidad Católica de Chile, V. Mackenna 4860 Santiago 22 (Chile); and others

    2015-03-01

    We utilize the Cluster Lensing And Supernova survey with Hubble observations of 25 clusters to search for extreme emission-line galaxies (EELGs). The selections are carried out in two central bands: F105W (Y {sub 105}) and F125W (J {sub 125}), as the flux of the central bands could be enhanced by the presence of [O III] λλ4959, 5007 at redshifts of ∼0.93-1.14 and 1.57-1.79, respectively. The multiband observations help to constrain the equivalent widths (EWs) of emission lines. Thanks to cluster lensing, we are able to identify 52 candidates down to an intrinsic limiting magnitude of 28.5 and to a rest-frame [O III] λλ4959, 5007 EW of ≅ 3700 Å. Our samples include a number of EELGs at lower luminosities that are missed in other surveys, and the extremely high EW can only be found in such faint galaxies. These EELGs can mimic a dropout feature similar to that of high-redshift galaxies and contaminate the color-color selection of high-redshift galaxies when the signal-to-noise ratio is limited or the band coverage is incomplete.

  12. Experimental Contribution to High-Precision Characterization of Magnetic Forces in Active Magnetic Bearings

    DEFF Research Database (Denmark)

    Kjølhede, Klaus; Santos, Ilmar

    2007-01-01

    Parameter identification procedures and model validation are major steps toward intelligent machines supported by active magnetic bearings (AMB). The ability of measuring the electromagnetic bearing forces, or deriving them from measuring the magnetic flux, strongly contributes to the model...... of the magnetic forces is conducted using different experimental tests: (i) by using hall sensors mounted directly on the poles (precise measurements of the magnetic flux) and by an auxiliary system, composed of strain gages and flexible beams attached to the rotor (ii) by measuring the input current and bearing...... gap variations, monitoring the bearing input signals. Advantages and drawbacks of the different methodologies are critically discussed. The linearity ranges are experimentally determined and the characterization of magnetic forces with a high accuracy of

  13. Experimental Contribution to High Precision Characterization of Magnetic Forces in Active Magnetic Bearings

    DEFF Research Database (Denmark)

    Kjølhede, Klaus; Santos, Ilmar

    2006-01-01

    Parameter identification procedures and model validation are major steps towards intelligent machines supported by active magnetic bearings (AMB). The ability of measuring the electromagnetic bearing forces, or deriving them from measuring the magnetic flux, strongly contributes to the model...... of the magnetic forces is conducted using different experimental tests: (a) by using hall sensors mounted directly on the poles (precise measurements of the magnetic flux) and by an auxiliary system, composed of strain gages and flexible beams attached to the rotor, (b) by measuring the input current and bearing...... gap variations, monitoring the bearing input signals. Advantages and drawbacks of the different methodologies are critically discussed. The linearity ranges are experimentally determined and the characterization of magnetic forces with a high accuracy of less than 1% is achieved. (%error is normalized...

  14. Laboratory measurements of materials in extreme conditions; The use of high energy radiation sources for high pressure studies

    Energy Technology Data Exchange (ETDEWEB)

    Cauble, R.; Remington, B.A.

    1998-06-01

    High energy lasers can be used to study material conditions that are appropriate fort inertial confinement fusion: that is, materials at high densities, temperatures, and pressures. Pulsed power devices can offer similar opportunities. The National Ignition Facility (NIF) will be a high energy multi-beam laser designed to achieve the thermonuclear ignition of a mm-scale DT-filled target in the laboratory. At the same time, NE will provide the physics community with a unique tool for the study of high energy density matter at states unreachable by any other laboratory technique. Here we describe how these lasers and pulsed power tools can contribute to investigations of high energy density matter in the areas of material properties and equations of state, extend present laboratory shock techniques such as high-speed jets to new regimes, and allow study of extreme conditions found in astrophysical phenomena.

  15. Polarization of radiation of electrons in highly turbulent magnetic fields

    Science.gov (United States)

    Prosekin, A. Yu.; Kelner, S. R.; Aharonian, F. A.

    2016-09-01

    We study the polarization properties of the jitter and synchrotron radiation produced by electrons in highly turbulent anisotropic magnetic fields. The net polarization is provided by the geometry of the magnetic field the directions of which are parallel to a certain plane. Such conditions may appear in the relativistic shocks during the amplification of the magnetic field through the so-called Weibel instability. While the polarization properties of the jitter radiation allows extraction of direct information on the turbulence spectrum as well as the geometry of magnetic field, the polarization of the synchrotron radiation reflects the distribution of the magnetic field over its strength. For the isotropic distribution of monoenergetic electrons, we found that the degree of polarization of the synchrotron radiation is larger than the polarization of the jitter radiation. For the power-law energy distribution of electrons the relation between the degree of polarization of synchrotron and jitter radiation depends on the spectral index of the distribution.

  16. Polarization of radiation of electrons in highly turbulent magnetic fields

    CERN Document Server

    Prosekin, A Yu; Aharonian, F A

    2016-01-01

    We study the polarization properties of the jitter and synchrotron radiation produced by electrons in highly turbulent anisotropic magnetic fields. The net polarization is provided by the geometry of the magnetic field the directions of which are parallel to a certain plane. Such conditions may appear in the relativistic shocks during the amplification of the magnetic field through the so-called Weibel instability. While the polarization properties of the jitter radiation allows extraction of direct information on the turbulence spectrum as well as the geometry of magnetic field, the polarization of the synchrotron radiation reflects the distribution of the magnetic field over its strength. For the isotropic distribution of monoenergetic electrons, we found that the degree of polarization of the synchrotron radiation is larger than the polarization of the jitter radiation. For the power-law energy distribution of electrons the relation between the degree of polarization of synchrotron and jitter radiation dep...

  17. Si:P as a laboratory analogue for hydrogen on high magnetic field white dwarf stars.

    Science.gov (United States)

    Murdin, B N; Li, Juerong; Pang, M L Y; Bowyer, E T; Litvinenko, K L; Clowes, S K; Engelkamp, H; Pidgeon, C R; Galbraith, I; Abrosimov, N V; Riemann, H; Pavlov, S G; Hübers, H-W; Murdin, P G

    2013-01-01

    Laboratory spectroscopy of atomic hydrogen in a magnetic flux density of 10(5) T (1 gigagauss), the maximum observed on high-field magnetic white dwarfs, is impossible because practically available fields are about a thousand times less. In this regime, the cyclotron and binding energies become equal. Here we demonstrate Lyman series spectra for phosphorus impurities in silicon up to the equivalent field, which is scaled to 32.8 T by the effective mass and dielectric constant. The spectra reproduce the high-field theory for free hydrogen, with quadratic Zeeman splitting and strong mixing of spherical harmonics. They show the way for experiments on He and H(2) analogues, and for investigation of He(2), a bound molecule predicted under extreme field conditions.

  18. Generation of Bright Phase-matched Circularly-polarized Extreme Ultraviolet High Harmonics

    Science.gov (United States)

    2014-12-08

    relation to local moments. Phys. Scr . 1993, 302 (1993). 7. Stöhr, J. et al. Element-specific magnetic microscopy with circularly polarized X-rays...Becker, W. & Kopold, R. Generation of circularly polarized high-order harmonics by two-color coplanar field mixing . Phys. Rev. A 61, 063403 (2000). 38...1995). 42. Eichmann, H. et al. Polarization-dependent high-order two-color mixing . Phys. Rev. A 51, R3414–R3417 (1995). 43. Fleischer, A., Kfir, O

  19. Ultra-high field magnets for whole-body MRI

    Science.gov (United States)

    Warner, Rory

    2016-09-01

    For whole-body MRI, an ultra-high field (UHF) magnet is currently defined as a system operating at 7 T or above. Over 70 UHF magnets have been built, all with the same technical approach originally developed by Magnex Scientific Ltd. The preferred coil configuration is a compensated solenoid. In this case, the majority of the field is generated by a simple long solenoid that stretches the entire length of the magnet. Additional coils are wound on a separate former outside the main windings with the purpose of balancing the homogeneity. Most of the magnets currently in operation are passively shielded systems where the magnet is surrounded by a steel box of 200-870 tonnes of carbon steel. More recently actively shielded magnets have been built for operation at 7 T; in this case the stray field is controlled by with reverse turns wound on a separate former outside the primary coils. Protection against quench damage is much more complex with an actively shielded magnet design due to the requirement to prevent the stray field from increasing during a quench. In the case of the 7 T 900 magnet this controlled by combining some of the screening coils into each section of the protection circuit. Correction of the field variations caused by manufacturing tolerances and environmental effects are made with a combination of superconducting shims and passive shims. Modern UHF magnets operate in zero boil-off mode with the use of cryocoolers with cooling capacity at 4.2 K. Although there are no cryogen costs associated with normal operation UHF magnets require a significant volume (10 000-20 000 l) of liquid helium for the cool-down. Liquid helium is expensive therefore new methods of cool-down using high-power cryocoolers are being implemented to reduce the requirement.

  20. Bringing Earth Magnetism Research into the High School Physics Classroom

    Science.gov (United States)

    Smirnov, A. V.; Bluth, G.; Engel, E.; Kurpier, K.; Foucher, M. S.; Anderson, K. L.

    2015-12-01

    We present our work in progress from an NSF CAREER project that aims to integrate paleomagnetic research and secondary school physics education. The research project is aimed at quantifying the strength and geometry of the Precambrian geomagnetic field. Investigation of the geomagnetic field behavior is crucial for understanding the mechanisms of field generation, and the development of the Earth's atmosphere and biosphere, and can serve as a focus for connecting high-level Earth science research with a standard physics curriculum. High school science teachers have participated in each summer field and research component of the project, gaining field and laboratory research experience, sets of rock and mineral samples, and classroom-tested laboratory magnetism activities for secondary school physics and earth science courses. We report on three field seasons of teacher field experiences and two years of classroom testing of paleomagnetic research materials merged into physics instruction on magnetism. Students were surveyed before and after dedicated instruction for both perceptions and attitude towards earth science in general, then more specifically on earth history and earth magnetism. Students were also surveyed before and after instruction on major earth system and magnetic concepts and processes, particularly as they relate to paleomagnetic research. Most students surveyed had a strongly positive viewpoint towards the study of Earth history and the importance of studying Earth Sciences in general, but were significantly less drawn towards more specific topics such as mineralogy and magnetism. Students demonstrated understanding of Earth model and the basics of magnetism, as well as the general timing of life, atmospheric development, and magnetic field development. However, detailed knowledge such as the magnetic dynamo, how the magnetic field has changed over time, and connections between earth magnetism and the development of an atmosphere remained largely

  1. A detailed ethological analysis of the mouse open field test: effects of diazepam, chlordiazepoxide and an extremely low frequency pulsed magnetic field.

    Science.gov (United States)

    Choleris, E; Thomas, A W; Kavaliers, M; Prato, F S

    2001-05-01

    The open field test (OFT) is a widely used procedure for examining the behavioral effects of drugs and anxiety. Detailed ethological assessments of animal behavior are lacking. Here we present a detailed ethological assessment of the effects of acute treatment with the benzodiazepines, diazepam (DZ, 1.5mg/kg) and chlordiazepoxide (CDP, 5.0 and 10.0mg/kg), as well as exposure to a non-pharmacological agent, a specific pulsed extremely low frequency magnetic field (MAG) on open field behavior. We examined the duration, frequency and time course of various behaviors (i.e. exploration, walk, rear, stretch attend, return, groom, sit, spin turn, jump and sleep) exhibited by male mice in different regions of a novel open field. Both DZ and CDP consistently reduced the typical anxiety-like behaviors of stretch attend and wall-following (thigmotaxis), along with that of an additional new measure: 'returns', without producing any overall effects on total locomotion. The drugs also differed in their effects. CDP elicited a shift in the locomotor pattern from a 'high explore' to a 'high walk', while DZ mainly elicited alterations in sit and groom. The MAG treatment was repeated twice with both exposures reducing horizontal and vertical (rearing) activity and increasing grooming and spin turns. However, the anxiety-like behaviors of stretch attend and return were marginally reduced by only the first exposure. We conclude that a detailed ethological analysis of the OFT allows not only the detection of specific effects of drugs and non-pharmacological agents (i.e. pulsed magnetic field) on anxiety-like behaviors, but also permits the examination of non-specific effects, in particular those on general activity.

  2. Silicon-Carbide Power MOSFET Performance in High Efficiency Boost Power Processing Unit for Extreme Environments

    Science.gov (United States)

    Ikpe, Stanley A.; Lauenstein, Jean-Marie; Carr, Gregory A.; Hunter, Don; Ludwig, Lawrence L.; Wood, William; Del Castillo, Linda Y.; Fitzpatrick, Fred; Chen, Yuan

    2016-01-01

    Silicon-Carbide device technology has generated much interest in recent years. With superior thermal performance, power ratings and potential switching frequencies over its Silicon counterpart, Silicon-Carbide offers a greater possibility for high powered switching applications in extreme environment. In particular, Silicon-Carbide Metal-Oxide- Semiconductor Field-Effect Transistors' (MOSFETs) maturing process technology has produced a plethora of commercially available power dense, low on-state resistance devices capable of switching at high frequencies. A novel hard-switched power processing unit (PPU) is implemented utilizing Silicon-Carbide power devices. Accelerated life data is captured and assessed in conjunction with a damage accumulation model of gate oxide and drain-source junction lifetime to evaluate potential system performance at high temperature environments.

  3. Strongly Driven Magnetic Reconnection in a Magnetized High-Energy-Density Plasma

    Science.gov (United States)

    Fiksel, G.; Barnak, D. H.; Chang, P.-Y.; Haberberger, D.; Hu, S. X.; Ivancic, S.; Nilson, P. M.; Fox, W.; Deng, W.; Bhattacharjee, A.; Germaschewski, K.

    2014-10-01

    Magnetic reconnection in a magnetized high-energy-density plasma is characterized by measuring the dynamics of the plasma density and magnetic field between two counter-propagating and colliding plasma flows. The density and magnetic field were profiled using the 4 ω angular filter refractometry and fast proton deflectometry diagnostics, respectively. The plasma flows are created by irradiating oppositely placed plastic targets with 1.8-kJ, 2-ns laser beams on the OMEGA EP Laser System. The two plumes are magnetized by an externally controlled magnetic field with an x-type null point geometry with B = 0 at the midplane and B = 8 T at the targets. The interaction region is pre-filled with a low-density background plasma. The counterflowing super-Alfvénic plasma plumes sweep up and compress the magnetic field and the background plasma into a pair of magnetized ribbons, which collide, stagnate, and reconnect at the midplane, allowing for the first detailed observation of a stretched current sheet in laser-driven reconnection experiments. The measurements are in good agreement with first-principles particle-in-cell simulations. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and NLUF Grant DE-SC0008655.

  4. Extreme ultraviolet and soft x-ray diagnostics of high-temperature plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Moos, W.

    1986-10-02

    This report describes recent progress and plans for calendar year 1987 in the Johns Hopkins University program to develop and improve spectroscopic diagnostics for the high temperature plasmas used in magnetic fusion research. An EUV spectrograph which provides time resolved spectra along fifteen chords of a plasma device has been completed and evaluation on DIII-D will began in late 1986. Other instrumentation work includes the evaluation of a sensitive detector for ion temperature/velocity distribution determinations and a feasibility study of Zeeman polarimetry for determining magnetic fields. A comprehensive data set taken on the TEXT tokamak is undergoing analysis as a means of improving the ionic parameters used in diagnostic studies and to expand the capabilities of existing instruments. Potential new advanced in spectroscopic technology are being monitored to determine if they provide advantages for fusion research.

  5. Extreme ultraviolet and soft x-ray diagnostics of high-temperature plasmas. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Moos, W.

    1986-10-02

    This report describes recent progress and plans for calendar year 1987 in the Johns Hopkins University program to develop and improve spectroscopic diagnostics for the high temperature plasmas used in magnetic fusion research. An EUV spectrograph which provides time resolved spectra along fifteen chords of a plasma device has been completed and evaluation on DIII-D will began in late 1986. Other instrumentation work includes the evaluation of a sensitive detector for ion temperature/velocity distribution determinations and a feasibility study of Zeeman polarimetry for determining magnetic fields. A comprehensive data set taken on the TEXT tokamak is undergoing analysis as a means of improving the ionic parameters used in diagnostic studies and to expand the capabilities of existing instruments. Potential new advanced in spectroscopic technology are being monitored to determine if they provide advantages for fusion research.

  6. Brain Tumour Segmentation based on Extremely Randomized Forest with high-level features.

    Science.gov (United States)

    Pinto, Adriano; Pereira, Sergio; Correia, Higino; Oliveira, J; Rasteiro, Deolinda M L D; Silva, Carlos A

    2015-08-01

    Gliomas are among the most common and aggressive brain tumours. Segmentation of these tumours is important for surgery and treatment planning, but also for follow-up evaluations. However, it is a difficult task, given that its size and locations are variable, and the delineation of all tumour tissue is not trivial, even with all the different modalities of the Magnetic Resonance Imaging (MRI). We propose a discriminative and fully automatic method for the segmentation of gliomas, using appearance- and context-based features to feed an Extremely Randomized Forest (Extra-Trees). Some of these features are computed over a non-linear transformation of the image. The proposed method was evaluated using the publicly available Challenge database from BraTS 2013, having obtained a Dice score of 0.83, 0.78 and 0.73 for the complete tumour, and the core and the enhanced regions, respectively. Our results are competitive, when compared against other results reported using the same database.

  7. τ-MnAl with high coercivity and saturation magnetization

    Directory of Open Access Journals (Sweden)

    J. Z. Wei

    2014-12-01

    Full Text Available In this paper, high purity τ-Mn54Al46 and Mn54−xAl46Cxalloys were successfully prepared using conventional arc-melting, melt-spinning, and heat treatment process. The magnetic and the structural properties were examined using x-ray diffraction (XRD, powder neutron diffraction and magnetic measurements. A room temperature saturation magnetization of 650.5 kAm-1, coercivity of 0.5 T, and a maximum energy product of (BHmax = 24.7 kJm-3 were achieved for the pure Mn54Al46 powders without carbon doping. The carbon substituted Mn54−xAl46Cx, however, reveals a lower Curie temperature but similar saturation magnetization as compared to the carbon-free sample. The electronic structure of MnAl shows that the Mn atom possesses a magnetic moment of 2.454 μB which results from strong hybridization between Mn-Al and Mn-Mn. We also investigated the volume and c/a ratio dependence of the magnetic moments of Mn and Al. The results indicate that an increase in the intra-atomic exchange splitting due to the cell volume expansion, leads to a large magnetic moment for the Mn atom. The Mn magnetic moment can reach a value of 2.9 μB at a volume expansion rate of ΔV/V ≈ 20%.

  8. Design, performance, and early results from extremely high Doppler precision instruments in a global network

    Science.gov (United States)

    Ge, Jian; Zhao, Bo; Groot, John; Chang, Liang; Varosi, Frank; Wan, Xiaoke; Powell, Scott; Jiang, Peng; Hanna, Kevin; Wang, Ji; Pais, Rohan; Liu, Jian; Dou, Liming; Schofield, Sidney; McDowell, Shaun; Costello, Erin; Delgado-Navarro, Adriana; Fleming, Scott; Lee, Brian; Bollampally, Sandeep R.; Bosman, Troy; Jakeman, Hali; Fletcher, Adam; Marquez, Gabriel

    2010-07-01

    We report design, performance and early results from two of the Extremely High Precision Extrasolar Planet Tracker Instruments (EXPERT) as part of a global network for hunting for low mass planets in the next decade. EXPERT is a combination of a thermally compensated monolithic Michelson interferometer and a cross-dispersed echelle spectrograph for extremely high precision Doppler measurements for nearby bright stars (e.g., 1m/s for a V=8 solar type star in 15 min exposure). It has R=18,000 with a 72 micron slit and a simultaneous coverage of 390-694 nm. The commissioning results show that the instrument has already produced a Doppler precision of about 1 m/s for a solar type star with S/N~100 per pixel. The instrument has reached ~4 mK (P-V) temperature stability, ~1 mpsi pressure stability over a week and a total instrument throughput of ~30% at 550 nm from the fiber input to the detector. EXPERT also has a direct cross-dispersed echelle spectroscopy mode fed with 50 micron fibers. It has spectral resolution of R=27,000 and a simultaneous wavelength coverage of 390-1000 nm.

  9. Highly Efficient Domain Walls Injection in Perpendicular Magnetic Anisotropy Nanowire.

    Science.gov (United States)

    Zhang, S F; Gan, W L; Kwon, J; Luo, F L; Lim, G J; Wang, J B; Lew, W S

    2016-04-21

    Electrical injection of magnetic domain walls in perpendicular magnetic anisotropy nanowire is crucial for data bit writing in domain wall-based magnetic memory and logic devices. Conventionally, the current pulse required to nucleate a domain wall is approximately ~10(12) A/m(2). Here, we demonstrate an energy efficient structure to inject domain walls. Under an applied electric potential, our proposed Π-shaped stripline generates a highly concentrated current distribution. This creates a highly localized magnetic field that quickly initiates the nucleation of a magnetic domain. The formation and motion of the resulting domain walls can then be electrically detected by means of Ta Hall bars across the nanowire. Our measurements show that the Π-shaped stripline can deterministically write a magnetic data bit in 15 ns even with a relatively low current density of 5.34 × 10(11) A/m(2). Micromagnetic simulations reveal the evolution of the domain nucleation - first, by the formation of a pair of magnetic bubbles, then followed by their rapid expansion into a single domain. Finally, we also demonstrate experimentally that our injection geometry can perform bit writing using only about 30% of the electrical energy as compared to a conventional injection line.

  10. Highly Efficient Domain Walls Injection in Perpendicular Magnetic Anisotropy Nanowire

    Science.gov (United States)

    Zhang, S. F.; Gan, W. L.; Kwon, J.; Luo, F. L.; Lim, G. J.; Wang, J. B.; Lew, W. S.

    2016-04-01

    Electrical injection of magnetic domain walls in perpendicular magnetic anisotropy nanowire is crucial for data bit writing in domain wall-based magnetic memory and logic devices. Conventionally, the current pulse required to nucleate a domain wall is approximately ~1012 A/m2. Here, we demonstrate an energy efficient structure to inject domain walls. Under an applied electric potential, our proposed Π-shaped stripline generates a highly concentrated current distribution. This creates a highly localized magnetic field that quickly initiates the nucleation of a magnetic domain. The formation and motion of the resulting domain walls can then be electrically detected by means of Ta Hall bars across the nanowire. Our measurements show that the Π-shaped stripline can deterministically write a magnetic data bit in 15 ns even with a relatively low current density of 5.34 × 1011 A/m2. Micromagnetic simulations reveal the evolution of the domain nucleation – first, by the formation of a pair of magnetic bubbles, then followed by their rapid expansion into a single domain. Finally, we also demonstrate experimentally that our injection geometry can perform bit writing using only about 30% of the electrical energy as compared to a conventional injection line.

  11. Induction heating of rotating nonmagnetic billet in magnetic field produced by high-parameter permanent magnets

    Directory of Open Access Journals (Sweden)

    Ivo Doležel

    2014-04-01

    Full Text Available An advanced way of induction heating of nonmagnetic billets is discussed and modeled. The billet rotates in a stationary magnetic field produced by unmoving high-parameter permanent magnets fixed on magnetic circuit of an appropriate shape. The mathematical model of the problem consisting of two coupled partial differential equations is solved numerically, in the monolithic formulation. Computations are carried out using our own code Agros2D based on a fully adaptive higher-order finite element method. The most important results are verified experimentally on our own laboratory device.

  12. Magnetic Bearing Controller Improvements for High Speed Flywheel System

    Science.gov (United States)

    Dever, Timothy P.; Brown, Gerald V.; Jansen, Ralph H.; Kascak, Peter E.; Provenza, Andrew J.

    2003-01-01

    A magnetic bearing control system for a high-speed flywheel system is described. The flywheel utilizes a five axis active magnetic bearing system, using eddy current sensors for position feedback to the bearing controller. Magnetic bearing controller features designed to improve flywheel operation and testing are described. Operational improvements include feed forward control to compensate for rotor imbalance, moving notch filtering to compensate for synchronous and harmonic rotational noise, and fixed notching to prevent rotor bending mode excitation. Testing improvements include adding safe gain, bearing current hold, bearing current zero, and excitation input features. Performance and testing improvements provided by these features are measured and discussed.

  13. NANO-MULTILAYERS WITH HIGH PERPENDICULAR ANISOTROPY FOR MAGNETIC RECORDING

    Institute of Scientific and Technical Information of China (English)

    T. Yang; B.H. Li; K. Kang; T. Suzuki

    2003-01-01

    (FePt/Ag)n nano-multilayers were deposited on MgO (100) single crystal with laser ablation and then subjected to annealing. FePt L1o grains with (001) texture and thus a large perpendicular magnetic anisotropy constant Ku of the order of 106J/m3 were formed. A thick Ag layer is found to be favorable for decreasing the dispersion of the easy axis for magnetization. The measurement of time decay of magnetization gave rise to a small activation volume of the order of 10-25 m3, showing the promising of being the recording medium for future high density perpendicular recording.

  14. High Energy Electron Confinement in a Magnetic Cusp Configuration

    CERN Document Server

    Park, Jaeyoung; Sieck, Paul E; Offermann, Dustin T; Skillicorn, Michael; Sanchez, Andrew; Davis, Kevin; Alderson, Eric; Lapenta, Giovanni

    2014-01-01

    We report experimental results validating the concept that plasma confinement is enhanced in a magnetic cusp configuration when beta (plasma pressure/magnetic field pressure) is order of unity. This enhancement is required for a fusion power reactor based on cusp confinement to be feasible. The magnetic cusp configuration possesses a critical advantage: the plasma is stable to large scale perturbations. However, early work indicated that plasma loss rates in a reactor based on a cusp configuration were too large for net power production. Grad and others theorized that at high beta a sharp boundary would form between the plasma and the magnetic field, leading to substantially smaller loss rates. The current experiment validates this theoretical conjecture for the first time and represents critical progress toward the Polywell fusion concept which combines a high beta cusp configuration with an electrostatic fusion for a compact, economical, power-producing nuclear fusion reactor.

  15. On the origin of high-field magnetic white dwarfs

    CERN Document Server

    García-Berro, E; Lorén-Aguilar, P; Aznar-Siguán, G; Camacho, J; Külebi, B; Isern, J; Althaus, L G; Córsico, A H

    2012-01-01

    High-field magnetic white dwarfs have been long suspected to be the result of stellar mergers. However, the nature of the coalescing stars and the precise mechanism that produces the magnetic field are still unknown. Here we show that the hot, convective, differentially rotating corona present in the outer layers of the remnant of the merger of two degenerate cores is able to produce magnetic fields of the required strength that do not decay for long timescales. We also show, using an state-of-the-art Monte Carlo simulator, that the expected number of high-field magnetic white dwarfs produced in this way is consistent with that found in the solar neighborhood.

  16. Superconductor Requirements and Characterization for High Field Accelerator Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Barzi, E.; Zlobin, A. V.

    2015-05-01

    The 2014 Particle Physics Project Prioritization Panel (P5) strategic plan for U.S. High Energy Physics (HEP) endorses a continued world leadership role in superconducting magnet technology for future Energy Frontier Programs. This includes 10 to 15 T Nb3Sn accelerator magnets for LHC upgrades and a future 100 TeV scale pp collider, and as ultimate goal that of developing magnet technologies above 20 T based on both High Temperature Superconductors (HTS) and Low Temperature Superconductors (LTS) for accelerator magnets. To achieve these objectives, a sound conductor development and characterization program is needed and is herein described. This program is intended to be conducted in close collaboration with U.S. and International labs, Universities and Industry.

  17. High magnetic field {mu}SR instrument scientific case

    Energy Technology Data Exchange (ETDEWEB)

    Amato, A

    2005-10-15

    In order to gain more insight into the specific behavior of materials, it is often necessary to perform measurements as a function of different external parameters. Despite its high sensitivity to internal fields, this simple observation also applies for the {mu}SR technique. The most common parameter which can be tuned during an experiment is the sample temperature. By using a range of cryostats, temperatures between 0.02 and 900 K can be covered at the PSI {mu}SR Facility. On the other hand, and by using high-energy muons, pressures as high as 10'000 bars can nowadays be reached during {mu}SR experiments. As will be demonstrated in the following Sections, the magnetic field is an additional external parameter playing a fundamental role when studying the ground state properties of materials in condensed matter physics and chemistry. However, the availability of high magnetic fields for {mu}SR experiments is still rather limited. Hence, if on one hand the high value of the gyromagnetic ratio of the muon provides the high magnetic sensitivity of the method, on the other hand it can lead to very high muon-spin precession frequencies when performing measurements in applied fields (the muon-spin precession frequency in a field of 1 Tesla s 135.5 MHz). Consequently, the use of ultra-fast detectors and electronics is mandatory when measuring in magnetic fields exceeding 1 Tesla. If such fields are very intense when compared to the Earth magnetic field < 10{sup -4} Tesla), the energy associated with them is still modest in view of the thermal energy. Hence, the Zeeman energy splitting of a free electron in a magnetic field of 1 Tesla corresponds to a thermal energy as low as 0.67 Kelvin. It is worth mentioning that nowadays magnetic fields of the order of 10 to 15 Tesla are quite common in condensed matter laboratories and have opened up vast new exciting experimental possibilities. (author)

  18. Structure and magnetism of cobalt at high pressure and low temperature

    Science.gov (United States)

    Torchio, R.; Marini, C.; Kvashnin, Y. O.; Kantor, I.; Mathon, O.; Garbarino, G.; Meneghini, C.; Anzellini, S.; Occelli, F.; Bruno, P.; Dewaele, A.; Pascarelli, S.

    2016-07-01

    The magnetic and structural properties of cobalt were investigated under high pressure (160 GPa) and low temperature (50 K), by synchrotron K-edge x-ray magnetic circular dichroism and x-ray diffraction. A quasihydrostatic equation of state was measured up to 160 GPa. We found that uniaxial stress plays a role in the hexagonal close packed-face centered cubic (hcp-fcc) structural transition pressure. Also, our data provide the first experimental evidence that changes of the c /a ratio pressure derivative are related to the magnetic behavior. The complete extinction of ferromagnetism is observed above 130 GPa in a mixed hcp-fcc phase with no recovery upon cooling to 50 K, indicating that cobalt at 150 GPa is very likely nonmagnetic, i.e., characterized by zero local spin polarization. Density functional theory calculations point out that the K-edge x-ray magnetic circular dichroism (XMCD) signal is related to the 4 p orbital moment rather than to the total spin moment and allow us to get a deeper insight into the K-edge XMCD measurements interpretation. The combination of novel theoretical results and experimental outputs provides a detailed scenario of the structural and magnetic properties of cobalt at these extreme conditions answering some previously unsolved issues.

  19. Investigation of recurrent EUV jets from highly dynamic magnetic field region

    Science.gov (United States)

    Joshi, Navin Chandra; Chandra, Ramesh; Guo, Yang; Magara, Tetsuya; Zhelyazkov, Ivan; Moon, Young-Jae; Uddin, Wahab

    2017-01-01

    In this work, we present observations and interpretations of recurrent extreme ultraviolet (EUV) jets that occurred between 2012 July 1 21:00 UT and 2012 July 2 10:00 UT from the western edge of the NOAA active region 11513. Solar Dynamics Observatory/Atmospheric Imaging Assembly ( SDO/AIA), SDO/Helioseismic and Magnetic Imager ( SDO/HMI) and Reuven Ramaty High Energy Solar Spectroscopic Imager ( RHESSI) observations have been used for the present study. Observations as well as potential-field source-surface (PFSS) extrapolation suggest an open field configuration in the vicinity of the jet activity area. 18 EUV jets were observed from the western edge of the active region along the open field channel. All the jet events appeared to be non-homologous and show different morphological properties and evolution. Some of the jets were small and narrow in size while the others were huge and wide. The average speed of these jets ranges from {˜}47 to {˜}308 km s^{-1}. SDO/AIA 171 Å intensity profiles at the base of these jets show bumps corresponding to each jet, which is an evidence of recurrent magnetic reconnections. The magnetic field observation at the foot points of the jets revealed a very complex and dynamic magnetic activity which includes flux emergence, flux cancellation, dynamic motions, merging, separation, etc. We suggest that the recurrent jets are the result of recurrent magnetic reconnections among the various emerging bipolar fields themselves as well as with the open fields.

  20. The Behavior Of Asymmetric Frontal Couplings With Permanent Magnets In Magnetic Powder And High Temperature Environments

    Directory of Open Access Journals (Sweden)

    Ion DOBROTA

    2002-12-01

    Full Text Available The main purpose of this paper is the comparative analysis of the behavior of frontal couplings with Nd-Fe-B permanent magnets in difficult environments, specific to metallurgy – such as environments with magnetic powders and high temperature – in two constructive variants: symmetric couplings and asymmetric couplings (with divided poles. The results show the superior performance of asymmetric couplings under the given conditions

  1. Global Distribution of Extreme Precipitation and High-Impact Landslides in 2010 Relative to Previous Years

    Science.gov (United States)

    Kirschbaum, Dalia; Adler, Robert; Adler, David; Peters-Lidard, Christa; Huffman, George

    2012-01-01

    It is well known that extreme or prolonged rainfall is the dominant trigger of landslides worldwide. While research has evaluated the spatiotemporal distribution of extreme rainfall and landslides at local or regional scales using in situ data, few studies have mapped rainfall-triggered landslide distribution globally due to the dearth of landslide data and consistent precipitation information. This study uses a newly developed Global Landslide Catalog (GLC) and a 13-year satellite-based precipitation record from TRMM data. For the first time, these two unique products provide the foundation to quantitatively evaluate the co-occurrence of precipitation and landslides globally. Evaluation of the GLC indicates that 2010 had a large number of high-impact landslide events relative to previous years. This study considers how variations in extreme and prolonged satellite-based rainfall are related to the distribution of landslides over the same time scales for three active landslide areas: Central America, the Himalayan Arc, and central-eastern China. Several test statistics confirm that TRMM rainfall generally scales with the observed increase in landslide reports and fatal events for 2010 and previous years over each region. These findings suggest that the co-occurrence of satellite precipitation and landslide reports may serve as a valuable indicator for characterizing the spatiotemporal distribution of landslide-prone areas in order to establish a global rainfall-triggered landslide climatology. This study characterizes the variability of satellite precipitation data and reported landslide activity at the globally scale in order to improve landslide cataloging, forecasting and quantify potential triggering sources at daily, monthly and yearly time scales.

  2. High-Sensitivity Measurement of Density by Magnetic Levitation.

    Science.gov (United States)

    Nemiroski, Alex; Kumar, A A; Soh, Siowling; Harburg, Daniel V; Yu, Hai-Dong; Whitesides, George M

    2016-03-01

    This paper presents methods that use Magnetic Levitation (MagLev) to measure very small differences in density of solid diamagnetic objects suspended in a paramagnetic medium. Previous work in this field has shown that, while it is a convenient method, standard MagLev (i.e., where the direction of magnetization and gravitational force are parallel) cannot resolve differences in density mm) because (i) objects close in density prevent each other from reaching an equilibrium height due to hard contact and excluded volume, and (ii) using weaker magnets or reducing the magnetic susceptibility of the medium destabilizes the magnetic trap. The present work investigates the use of weak magnetic gradients parallel to the faces of the magnets as a means of increasing the sensitivity of MagLev without destabilization. Configuring the MagLev device in a rotated state (i.e., where the direction of magnetization and gravitational force are perpendicular) relative to the standard configuration enables simple measurements along the axes with the highest sensitivity to changes in density. Manipulating the distance of separation between the magnets or the lengths of the magnets (along the axis of measurement) enables the sensitivity to be tuned. These modifications enable an improvement in the resolution up to 100-fold over the standard configuration, and measurements with resolution down to 10(-6) g/cm(3). Three examples of characterizing the small differences in density among samples of materials having ostensibly indistinguishable densities-Nylon spheres, PMMA spheres, and drug spheres-demonstrate the applicability of rotated Maglev to measuring the density of small (0.1-1 mm) objects with high sensitivity. This capability will be useful in materials science, separations, and quality control of manufactured objects.

  3. High-field magnetization of dilute rare earths in yttrium

    DEFF Research Database (Denmark)

    Touborg, P.; Høg, J.; Cock, G. J.;

    1974-01-01

    Magnetization measurements have been performed on single crystals of Y containing small amounts of Tb, Dy, or Er at 4.2 K in fields up to 295 × 105 A/m (370 kOe). Crystal-field and molecular-field parameters obtained from measurements of the initial susceptibility versus temperature give...... a satisfactory quantitative account of the high-field magnetization. This includes characteristic features due to the crossing and mixing of crystal-field levels....

  4. Experimental evidence for Froehlich superconductivity in high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, N. [National High Magnetic Field Laboratory, LANL, MS-E536, Los Alamos, NM (United States)]. E-mail: nharrison@lanl.gov; Mielke, C.H.; Singleton, J. [National High Magnetic Field Laboratory, LANL, MS-E536, Los Alamos, NM (United States); Brooks, J.S. [National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL (United States); Tokumoto, M. [Electrotechnical Laboratory, Tsukuba, Ibaraki (Japan)

    2001-05-14

    Resistivity and irreversible magnetization data taken within the high magnetic field CDW{sub x} phase of the quasi-two-dimensional organic metal {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} are shown to be consistent with a field-induced inhomogeneous superconducting phase. In-plane skin depth measurements show that the resistive transition on entering the CDW{sub x} phase is both isotropic and representative of the bulk. (author). Letter-to-the-editor.

  5. Extreme Learning Machines on High Dimensional and Large Data Applications: A Survey

    Directory of Open Access Journals (Sweden)

    Jiuwen Cao

    2015-01-01

    Full Text Available Extreme learning machine (ELM has been developed for single hidden layer feedforward neural networks (SLFNs. In ELM algorithm, the connections between the input layer and the hidden neurons are randomly assigned and remain unchanged during the learning process. The output connections are then tuned via minimizing the cost function through a linear system. The computational burden of ELM has been significantly reduced as the only cost is solving a linear system. The low computational complexity attracted a great deal of attention from the research community, especially for high dimensional and large data applications. This paper provides an up-to-date survey on the recent developments of ELM and its applications in high dimensional and large data. Comprehensive reviews on image processing, video processing, medical signal processing, and other popular large data applications with ELM are presented in the paper.

  6. Extreme ultraviolet spectroscopy and atomic models of highly charged heavy ions in the Large Helical Device

    Science.gov (United States)

    Suzuki, C.; Murakami, I.; Koike, F.; Tamura, N.; Sakaue, H. A.; Morita, S.; Goto, M.; Kato, D.; Ohashi, H.; Higashiguchi, T.; Sudo, S.; O'Sullivan, G.

    2017-01-01

    We report recent results of extreme ultraviolet (EUV) spectroscopy of highly charged heavy ions in plasmas produced in the Large Helical Device (LHD). The LHD is an ideal source of experimental databases of EUV spectra because of high brightness and low opacity, combined with the availability of pellet injection systems and reliable diagnostic tools. The measured heavy elements include tungsten, tin, lanthanides and bismuth, which are motivated by ITER as well as a variety of plasma applications such as EUV lithography and biological microscopy. The observed spectral features drastically change between quasicontinuum and discrete depending on the plasma temperature, which leads to some new experimental identifications of spectral lines. We have developed collisional-radiative models for some of these ions based on the measurements. The atomic number dependence of the spectral feature is also discussed.

  7. Extreme Energy Events Project: Construction of the detectors and installation in Italian High Schools

    CERN Document Server

    Abbrescia, M; An, S; Antolini, R; Badalà, A; Baldini Ferroli, R; Bencivenni, G; Blanco, F; Bressan, E; Chiavassa, A; Chiri, C; Cifarelli, L; Cindolo, F; Coccia, E; De Pasquale, S; Di Giovanni, A; D’Incecco, M; Fabbri, F L; Frolov, V; Garbini, M; Gustavino, C; Hatzifotiadou, D; Imponente, G; Kim, J; La Rocca, P; Librizzi, F; Maggiora, A; Menghetti, H; Miozzi, S; Moro, R; Panareo, M; Pappalardo, G S; Piragino, G; Riggi, F; Romano, F; Sartorelli, G; Sbarra, C; Selvi, M; Serci, S; Williams, C; Zuyeuski, R

    2008-01-01

    The EEE Project, conceived by its leader Antonino Zichichi, aims to detect Extreme Energy Events of cosmic rays with an array of muon telescopes distributed over the Italian territory. The Project involves Italian High Schools in order to introduce young people to Physics, also countervailing the recent crisis of university scientific classes inscriptions. The detectors for the EEE telescopes are Multigap Resistive Plate Chambers (MRPC) and have been constructed by teams of High School students who went in shift at the CERN laboratories. The mechanics and the electronics were developed by groups of researchers from CERN, the Italian Centro Fermi and INFN. The first group of schools of the EEE Project has inaugurated their telescopes recently. A status report of the Project and the preliminary results are presented.

  8. The physiology of extremes: Ancel Keys and the International High Altitude Expedition of 1935.

    Science.gov (United States)

    Tracy, Sarah W

    2012-01-01

    This article examines the International High Altitude Expedition of 1935 and its significance in the life and science of Ancel Keys. Both the expedition and Keys's story afford excellent opportunities to explore the growing reach of interwar physiology into extreme climates-whether built or natural. As IHAE scientists assessed human performance and adaptation to hypoxia, low barometric pressure, and cold, they not only illuminated the physiological and psychological processes of high altitude acclimatization, but they also drew borderlines between the normal and the pathological, paved the way for the neocolonial exploitation of natural and human resources in Latin America, and pioneered field methods in physiology that were adapted and adopted by the Allied Forces during the Second World War. This case study in the physiology of place reveals the power and persistence of environmental determinism within biomedicine well into the twentieth century.

  9. Feasibility of High-Repetition, Task-Specific Training for Individuals With Upper-Extremity Paresis

    Science.gov (United States)

    Waddell, Kimberly J.; Birkenmeier, Rebecca L.; Moore, Jennifer L.; Hornby, T. George

    2014-01-01

    OBJECTIVE. We investigated the feasibility of delivering an individualized, progressive, high-repetition upper-extremity (UE) task-specific training protocol for people with stroke in the inpatient rehabilitation setting. METHOD. Fifteen patients with UE paresis participated in this study. Task-specific UE training was scheduled for 60 min/day, 4 days/wk, during occupational therapy for the duration of a participant’s inpatient stay. During each session, participants were challenged to complete ≥300 repetitions of various tasks. RESULTS. Participants averaged 289 repetitions/session, spending 47 of 60 min in active training. Participants improved on impairment and activity level outcome measures. CONCLUSION. People with stroke in an inpatient setting can achieve hundreds of repetitions of task-specific training in 1-hr sessions. As expected, all participants improved on functional outcome measures. Future studies are needed to determine whether this high-repetition training program results in better outcomes than current UE interventions. PMID:25005508

  10. Beyond Extreme Ultra Violet (BEUV) Radiation from Spherically symmetrical High-Z plasmas

    Science.gov (United States)

    Yoshida, Kensuke; Fujioka, Shinsuke; Higashiguchi, Takeshi; Ugomori, Teruyuki; Tanaka, Nozomi; Kawasaki, Masato; Suzuki, Yuhei; Suzuki, Chihiro; Tomita, Kentaro; Hirose, Ryouichi; Eshima, Takeo; Ohashi, Hayato; Nishikino, Masaharu; Scally, Enda; Nshimura, Hiroaki; Azechi, Hiroshi; O'Sullivan, Gerard

    2016-03-01

    Photo-lithography is a key technology for volume manufacture of high performance and compact semiconductor devices. Smaller and more complex structures can be fabricated by using shorter wavelength light in the photolithography. One of the most critical issues in development of the next generation photo-lithography is to increase energy conversion efficiency (CE) from laser to shorter wavelength light. Experimental database of beyond extreme ultraviolet (BEUV) radiation was obtained by using spherically symmetrical high-Z plasmas generated with spherically allocated laser beams. Absolute energy and spectra of BEUV light emitted from Tb, Gd, and Mo plasmas were measured with a absolutely calibrated BEUV calorimeter and a transmission grating spectrometer. 1.0 x 1012 W/cm2 is the optimal laser intensity to produced efficient BEUV light source plasmas with Tb and Gd targets. Maximum CE is achieved at 0.8% that is two times higher than the published CEs obtained with planar targets.

  11. Improvement of neurofeedback therapy for improved attention through facilitation of brain activity using local sinusoidal extremely low frequency magnetic field exposure.

    Science.gov (United States)

    Zandi Mehran, Yasaman; Firoozabadi, Mohammad; Rostami, Reza

    2015-04-01

    Traditional neurofeedback (NF) is a training approach aimed at altering brain activity using electroencephalography (EEG) rhythms as feedback. In NF training, external factors such as the subjects' intelligence can have an effect. In contrast, a low-energy NF system (LENS) does not require conscious effort from the subject, which results in fewer attendance sessions. However, eliminating the subject role seems to eliminate an important part of the NF system. This study investigated the facilitating effect on the theta-to-beta ratio from NF training, using a local sinusoidal extremely low frequency magnetic field (LSELF-MF) versus traditional NF. Twenty-four healthy, intelligent subjects underwent 10 training sessions to enhance beta (15-18 Hz), and simultaneously inhibit theta (4-7 Hz) and high beta (22-30 Hz) activity, at the Cz point in a 3-boat-race video game. Each session consisted of 3 statuses, PRE, DURING, and POST. In the DURING status, the NF training procedure lasted 10 minutes. Subjects were led to believe that they would be exposed to a magnetic field during NF training; however, 16 of the subjects who were assigned to the experimental group were really exposed to 45 Hz-360 µT LSELF-MF at Cz. For the 8 other subjects, only the coil was located at the Cz point with no exposure. The duty cycle of exposure was 40% (2-second exposure and 3-second pause). The results show that the theta-to-beta ratio in the DURING status of each group differs significantly from the PRE and POST statuses. Between-group analysis shows that the theta-to-beta ratio in the DURING status of the experimental group is significantly (P < .001) lower than in the sham group. The result shows the effect of LSELF-MF on NF training.

  12. Light-dependent and -independent behavioral effects of extremely low frequency magnetic fields in a land snail are consistent with a parametric resonance mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Prato, F.S.; Thomas, A.W. [Univ. of Western Ontario, London, Ontario (Canada)]|[St. Joseph`s Health Centre, London, Ontario (Canada); Kavaliers, M. [Univ. of Western Ontario, London, Ontario (Canada); Cullen, A.P. [Univ. of Waterloo, Ontario (Canada). School of Optometry

    1997-05-01

    Exposure to extremely low frequency (ELF) magnetic fields has been shown to attenuate endogenous opioid peptide mediated antinociception or analgesia in the terrestrial pulmonate snail, Cepaea nemoralis. Here the authors examine the roles of light in determining this effect and address the mechanisms associated with mediating the effects of the ELF magnetic fields in both the presence and absence of light. Specifically, they consider whether the magnetic field effects involve an indirect induced electric current mechanism or a direct effect such as a parametric resonance mechanism (PRM). They exposed snails in both the presence and absence of light at three different frequencies (30, 60, and 120 Hz) with static field values (B{sub DC}) and ELF magnetic field amplitude (peak) and direction (B{sub AC}) set according to the predictions of the PRM for Ca{sup 2+}. Analgesia was induced in snails by injecting them with an enkephalinase inhibitor, which augments endogenous opioid (enkephalin) activity. They found that the magnetic field exposure reduced this opioid-induced analgesia significantly more if the exposure occurred in the presence rather than the absence of light. However, the percentage reduction in analgesia in both the presence and absence of light was not dependent on the ELF frequency. This finding suggests that in both the presence and the absence of light the effect of the ELF magnetic field was mediated by a direct magnetic field detection mechanism such as the PRM rather than an induced current mechanism.

  13. Towards Integrated Design and Modeling of High Field Accelerator Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Caspi, S.; Ferracin, P.

    2006-06-01

    The next generation of superconducting accelerator magnets will most likely use a brittle conductor (such as Nb{sub 3}Sn), generate fields around 18 T, handle forces that are 3-4 times higher than in the present LHC dipoles, and store energy that starts to make accelerator magnets look like fusion magnets. To meet the challenge and reduce the complexity, magnet design will have to be more innovative and better integrated. The recent design of several high field superconducting magnets have now benefited from the integration between CAD (e.g. ProE), magnetic analysis tools (e.g. TOSCA) and structural analysis tools (e.g. ANSYS). Not only it is now possible to address complex issues such as stress in magnet ends, but the analysis can be better detailed an extended into new areas previously too difficult to address. Integrated thermal, electrical and structural analysis can be followed from assembly and cool-down through excitation and quench propagation. In this paper we report on the integrated design approach, discuss analysis results and point out areas of future interest.

  14. Phthalocyanine dye as an extremely photostable and highly fluorescent near-infrared labeling reagent

    Science.gov (United States)

    Peng, Xinzhan; Draney, Daniel R.; Volcheck, William M.; Bashford, Gregory R.; Lamb, Donald T.; Grone, Daniel L.; Zhang, Yonghong; Johnson, Craig M.

    2006-02-01

    Current organic fluorophores used as labeling reagents for biomolecule conjugation have significant limitations in photostability. This compromises their performance in applications that require a photostable fluorescent reporting group. For example, in molecular imaging and single molecule microscopy, photostable fluorescent labels are important for observing and tracking individual molecular events over extended period of time. We report in this paper an extremely photostable and highly fluorescent phthalocyanine dye, IRDye TM 700DX, as a near-infrared fluorescence labeling reagent to conjugate with biomolecules. This novel water-soluble silicon phthalocyanine dye has an isomericly pure chemical structure. The dye is about 45 to 128 times more photostable than current near-IR fluorophores, e.g. Alexa Fluor"R"680, Cy TM 5.5, Cy TM 7 and IRDye TM 800CW dyes; and about 27 times more photostable than tetramethylrhodamine (TMR), one of the most photostable organic dyes. This dye also meets all the other stringent requirements as an ideal fluorophore for biomolecules labeling such as excellent water solubility, no aggregation in high ionic strength buffer, large extinction coefficient and high fluorescent quantum yield. Antibodies conjugated with IRDye TM 700DX at high D/P ratio exist as monomeric species in high ionic buffer and have bright fluorescence. The IRDye TM 700DX conjugated antibodies generate sensitive, highly specific detection with very low background in Western blot and cytoblot assays.

  15. Fast calculation of magnetic field distribution in magnetic gear for high torque application

    DEFF Research Database (Denmark)

    Zhang, Xiaoxu; Liu, Xiao; Song, Zhanfeng

    2016-01-01

    For applications demanding high torque and high reliability transmission, coaxial magnetic gear (CMG) may be a promising substitute of the mechanical gearbox. However, with the increasing of unit capacity, CMG tends to have a big size with large pole number, which would lead to heavy computation...

  16. Environmental extremes versus ecological extremes: impact of a massive iceberg on the population dynamics of a high-level Antarctic marine predator†

    Science.gov (United States)

    Chambert, Thierry; Rotella, Jay J.; Garrott, Robert A.

    2012-01-01

    Extreme events have been suggested to play a disproportionate role in shaping ecological processes, but our understanding of the types of environmental conditions that elicit extreme consequences in natural ecosystems is limited. Here, we investigated the impact of a massive iceberg on the dynamics of a population of Weddell seals. Reproductive rates of females were reduced, but survival appeared unaffected. We also found suggestive evidence for a prolonged shift towards higher variability in reproductive rates. The annual number of females attending colonies showed unusual swings during the iceberg period, a pattern that was apparently the consequence of changes in sea-ice conditions. In contrast to the dramatic effects that were recorded in nearby populations of emperor penguins, our results suggest that this unusual environmental event did not have an extreme impact on the population of seals in the short-term, as they managed to avoid survival costs and were able to rapidly re-achieve high levels of reproduction by the end of the perturbation. Nevertheless, population projections suggest that even this modest impact on reproductive rates could negatively affect the population in the long run if such events were to occur more frequently, as is predicted by models of climate change. PMID:23015628

  17. Radiofrequency solutions in clinical high field magnetic resonance

    NARCIS (Netherlands)

    Andreychenko, A.|info:eu-repo/dai/nl/341697672

    2013-01-01

    Magnetic resonance imaging (MRI) and spectroscopy (MRS) benefit from the sensitivity gain at high field (≥7T). However, high field brings also certain challenges associated with growing frequency and spectral dispersion. Frequency growth results in degraded performance of large volume radiofrequency

  18. Magnetic Field Structure in a High-mass System

    NARCIS (Netherlands)

    Beuther, H.; Vlemmings, W. H. T.; Rao, R.; van der Tak, F. F. S.

    2010-01-01

    To characterize the magnetic field structure of the outflow and core region within a prototypical high-mass star-forming region, we analyzed polarized CO(3-2)-for the first time observed with the Submillimeter Array-as well as 880 mu m submillimeter continuum emission from the high-mass outflow/disk

  19. High-Speed Photo-Polarimetry of Magnetic Cataclysmic Variables

    Directory of Open Access Journals (Sweden)

    S. B. Potter

    2015-02-01

    Full Text Available I review recent highlights of the SAAO High-speed Photo-POlarimeter (HIPPO on the study of magnetic Cataclysmic Variables. Its high-speed capabilities are demonstrated with example observations made of the intermediate polar NY Lup and the polar IGRJ14536-5522.

  20. Magnetic Resonance Imaging of Phosphocreatine and Determination of BOLD Kinetics in Lower Extremity Muscles using a Dual-Frequency Coil Array.

    Science.gov (United States)

    Brown, Ryan; Khegai, Oleksandr; Parasoglou, Prodromos

    2016-07-28

    Magnetic resonance imaging (MRI) provides the unique ability to study metabolic and microvasculature functions in skeletal muscle using phosphorus and proton measurements. However, the low sensitivity of these techniques can make it difficult to capture dynamic muscle activity due to the temporal resolution required for kinetic measurements during and after exercise tasks. Here, we report the design of a dual-nuclei coil array that enables proton and phosphorus MRI of the human lower extremities with high spatial and temporal resolution. We developed an array with whole-volume coverage of the calf and a phosphorus signal-to-noise ratio of more than double that of a birdcage coil in the gastrocnemius muscles. This enabled the local assessment of phosphocreatine recovery kinetics following a plantar flexion exercise using an efficient sampling scheme with a 6 s temporal resolution. The integrated proton array demonstrated image quality approximately equal to that of a clinical state-of-the-art knee coil, which enabled fat quantification and dynamic blood oxygen level-dependent measurements that reflect microvasculature function. The developed array and time-efficient pulse sequences were combined to create a localized assessment of calf metabolism using phosphorus measurements and vasculature function using proton measurements, which could provide new insights into muscle function.

  1. Magnetic Resonance Imaging of Phosphocreatine and Determination of BOLD Kinetics in Lower Extremity Muscles using a Dual-Frequency Coil Array

    Science.gov (United States)

    Brown, Ryan; Khegai, Oleksandr; Parasoglou, Prodromos

    2016-07-01

    Magnetic resonance imaging (MRI) provides the unique ability to study metabolic and microvasculature functions in skeletal muscle using phosphorus and proton measurements. However, the low sensitivity of these techniques can make it difficult to capture dynamic muscle activity due to the temporal resolution required for kinetic measurements during and after exercise tasks. Here, we report the design of a dual-nuclei coil array that enables proton and phosphorus MRI of the human lower extremities with high spatial and temporal resolution. We developed an array with whole-volume coverage of the calf and a phosphorus signal-to-noise ratio of more than double that of a birdcage coil in the gastrocnemius muscles. This enabled the local assessment of phosphocreatine recovery kinetics following a plantar flexion exercise using an efficient sampling scheme with a 6 s temporal resolution. The integrated proton array demonstrated image quality approximately equal to that of a clinical state-of-the-art knee coil, which enabled fat quantification and dynamic blood oxygen level-dependent measurements that reflect microvasculature function. The developed array and time-efficient pulse sequences were combined to create a localized assessment of calf metabolism using phosphorus measurements and vasculature function using proton measurements, which could provide new insights into muscle function.

  2. Metastable cobalt nitride structures with high magnetic anisotropy for rare-earth free magnets.

    Science.gov (United States)

    Zhao, Xin; Ke, Liqin; Wang, Cai-Zhuang; Ho, Kai-Ming

    2016-11-23

    Metastable structures of cobalt nitrides and Fe-substituted cobalt nitrides are explored as possible candidates for rare-earth free permanent magnets. Through crystal structure searches using an adaptive genetic algorithm, new structures of ConN (n = 3…8) are found to have lower energies than those previously discovered by experiments. Some structures exhibit large magnetic anisotropy energy, reaching as high as 200 μeV per Co atom (or 2.45 MJ m(-3)) based on first-principles density functional calculation. Substituting a fraction of Co with Fe helps in stabilizing new structures and at the same time further improves the magnetic properties. Our theoretical predictions provide useful insights into a promising system for the discovery of new rare-earth free magnets by experiment.

  3. Strong and moldable cellulose magnets with high ferrite nanoparticle content.

    Science.gov (United States)

    Galland, Sylvain; Andersson, Richard L; Ström, Valter; Olsson, Richard T; Berglund, Lars A

    2014-11-26

    A major limitation in the development of highly functional hybrid nanocomposites is brittleness and low tensile strength at high inorganic nanoparticle content. Herein, cellulose nanofibers were extracted from wood and individually decorated with cobalt-ferrite nanoparticles and then for the first time molded at low temperature (ferrite and cellulose material. A nanocomposite with 70 wt % ferrite, 20 wt % cellulose nanofibers, and 10 wt % epoxy showed a modulus of 12.6 GPa, a tensile strength of 97 MPa, and a strain at failure of ca. 4%. Magnetic characterization was performed in a vibrating sample magnetometer, which showed that the coercivity was unaffected and that the saturation magnetization was in proportion with the ferrite content. The used ferrite, CoFe2O4, is a magnetically hard material, demonstrated by that the composite material behaved as a traditional permanent magnet. The presented processing route is easily adaptable to prepare millimeter-thick and moldable magnetic objects. This suggests that the processing method has the potential to be scaled-up for industrial use for the preparation of a new subcategory of magnetic, low-cost, and moldable objects based on cellulose nanofibers.

  4. Micromagnetic simulation for high field sensors with perpendicular magnetizations

    Institute of Scientific and Technical Information of China (English)

    Jin Wei; Liu Yao-Wen

    2007-01-01

    In this paper, we present a micromagnetic design for high field sensors. The hard layer of the sensors is L10-FePt which is magnetized perpendicularly to film plane and the sense layer is NiFe which is magnetized in the film plane. The magnetization configurations of the hard and sense layers at different external magnetic fields have been simulated. In micromagnetic simulation, the sense field up to one tesla can be reached by using this sensor. We find that whether the sensor has a symmetric or an asymmetric field-sensing window is determined by the coercive field of the hard layer and the demagnetizing field of the sense layer.

  5. Functionalized magnetic mesoporous silica nanoparticles for U removal from low and high pH groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dien, E-mail: dien.li@srs.gov [Savannah River National Laboratory, Aiken, SC 29808 (United States); Egodawatte, Shani [Department of Chemistry, University of Iowa, Iowa City, IA 52242 (United States); Kaplan, Daniel I. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Larsen, Sarah C. [Department of Chemistry, University of Iowa, Iowa City, IA 52242 (United States); Serkiz, Steven M. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Seaman, John C. [Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802 (United States)

    2016-11-05

    Highlights: • Magnetic mesoporous silica nanoparticles were functionalized with organic molecules. • The functionalized nanoparticles had high surface areas and consistent pore sizes. • The functionalized nanoparticles were easily separated due to their magnetism. • They exhibited high capacity for uranium removal from low- or high-pH groundwater. - Abstract: U(VI) species display limited adsorption onto sediment minerals and synthetic sorbents in pH <4 or pH >8 groundwater. In this work, magnetic mesoporous silica nanoparticles (MMSNs) with magnetite nanoparticle cores were functionalized with various organic molecules using post-synthetic methods. The functionalized MMSNs were characterized using N{sub 2} adsorption-desorption isotherms, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), {sup 13}C cross polarization and magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectroscopy, and powder X-ray diffraction (XRD), which indicated that mesoporous silica (MCM-41) particles of 100–200 nm formed around a core of magnetic iron oxide, and the functional groups were primarily grafted into the mesopores of ∼3.0 nm in size. The functionalized MMSNs were effective for U removal from pH 3.5 and 9.6 artificial groundwater (AGW). Functionalized MMSNs removed U from the pH 3.5 AGW by as much as 6 orders of magnitude more than unfunctionalized nanoparticles or silica and had adsorption capacities as high as 38 mg/g. They removed U from the pH 9.6 AGW as much as 4 orders of magnitude greater than silica and 2 orders of magnitude greater than the unfunctionalized nanoparticles with adsorption capacities as high as 133 mg/g. These results provide an applied solution for treating U contamination that occurs at extreme pH environments and a scientific foundation for solving critical industrial issues related to environmental stewardship and nuclear power production.

  6. Retears of postoperative knee meniscus: findings on magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) by using low and high field magnets

    Energy Technology Data Exchange (ETDEWEB)

    Cardello, Paolo; Pofi, Enrico [Belcolle Hospital, Department of Radiodiagnostic, Viterbo (Italy); Gigli, Carlo; Voglino, Nicola [Belcolle Hospital, Division of Knee Surgery and Arthroscopy, Department of Orthopedics and Traumatology, Viterbo (Italy); Ricci, Alessandra; Chiatti, Leonardo [Belcolle Hospital, Department of Medical Physics, Viterbo (Italy)

    2009-02-15

    The purpose of this study was to determine the diagnostic performance of magnetic resonance (MR) obtained with intra-articular contrast medium in the evaluation of recurrent meniscal tears using low-field extremity-only and high-field whole-body magnets. Postoperative standard MR examinations and MR arthrographies of 95 knees were reviewed. Patients experiencing pain and disability after meniscal repair underwent standard MR and MR arthrography (Gadoterate meglumine 0.0025 mmol/ml) on both a 0.2-T and 1.5-T magnet. In 52 of 95 patients, second-look arthroscopy was performed; in the remaining 43 of 95 patients, clinical follow-up was used as the standard of reference. Sensitivity, specificity, positive and negative predictive values as well as accuracy of MRI/MR arthrographic signs as meniscal morphologic changes and the presence of contrast medium tracking into the tear at T1- and T2-weighted sequences in the detection of recurrent meniscal tears were determined. All MR and MR arthrograpic signs were sensitive in the detection of recurrent tears (range 80-91%). Abnormal meniscal morphology had low specificity [26% (13/50)] for both the 0.2-T and 1.5-T scanner, whereas accuracy was 55% (52/95) and 57% (54/95), respectively. The presence of contrast medium within the meniscus substance on T2-weighted images had higher value of specificity [84% (42/50)] and accuracy [84% (80/95)] by using low field strength magnet than by using high field strength magnet [74% (37/50) and 81% (77/95), respectively]. Whereas, the increased intrameniscal signal intensity extending to the meniscal surface at T1-weighted sequences after intra-articular contrast medium administration had lower specificity and accuracy on 0.2-T images [84% (42/50) and 82% (78/95), respectively] than on 1.5-T images [90% (45/50) and 88% (84/95), respectively]. A diagnosis of recurrent meniscal tear in a previously arthroscopically repaired meniscus can be made both on 0.2-T and 1.5-T magnets on the basis of

  7. Radio spectrum evolution and magnetic field in extreme GPS radio sources. The case of RXJ1459+3337

    CERN Document Server

    Orienti, M

    2007-01-01

    Aims: The knowledge of the properties of the youngest radio sources is very important in order to trace the earliest phase of the evolution of the radio emission. RXJ1459+3337, with its high turnover frequency (~25 GHz) provides a unique opportunity to study this class of extreme objects. Methods: High-sensitivity multi-frequency VLA observations have been carried out to measure the flux-density with high accuracy, while multi-frequency VLBA observations were performed, aimed at determining the pc-scale structure. Archival ROSAT data have been used to infer the X-ray luminosity. Results: The comparison between our new VLA data and those available in the literature shows a steady increment of the flux-density in the optically-thick part of the spectrum and a decrement of the turnover frequency. In the optically-thin regime, the source flux density has already started to decrease. Such a variability can be explained in terms of an adiabatically-expanding homogeneous radio component. The frequency range spanned ...

  8. Developments at the High Field Magnet Laboratory in Nijmegen

    Science.gov (United States)

    Perenboom, J. A. A. J.; Maan, J. C.; van Breukelen, M. R.; Wiegers, S. A. J.; den Ouden, A.; Wulffers, C. A.; van der Zande, W. J.; Jongma, R. T.; van der Meer, A. F. G.; Redlich, B.

    2013-03-01

    The High Field Magnet Laboratory at the Radboud University Nijmegen is rapidly expanding its capabilities. The developments encompass both organizational changes and new possibilities for research. The organization of the HFML was strengthened as a consequence of stronger participation of the Foundation for Fundamental Research on Matter (FOM), and an increase of the core-funding. This change makes that HFML is now considered on a national level as large research facility that operates at an international scale. At the same time work is underway to build new and powerful magnets, and provide electromagnetic radiation for magneto-spectroscopic studies. Electromagnetic radiation in the infrared and far-infrared spectrum will soon be available in the HFML with wavelengths between 3 μm and 1.5 mm, produced by the `FELIX' facility, comprising the long-wavelength free electron laser `FLARE' that in September 2011 produced its first light and the free electron lasers that have been moved from Rijnhuizen to Nijmegen. In magnet technology great strides are made to make magnets available for the user community with unprecedented performance: late in 2012 we hope to commission a new all-resistive magnet system that will generate a steady magnetic field as high as 38 T, by fully exploiting the maximum power of the installation, i.e. 20 MW, and using all available improvements in the design and construction of `Florida-Bitter' resistive magnets. We are also well underway with the design of a 45 T hybrid magnet system, using Nb3Sn superconductors and wind-and-react Cable-in-Conduit technology.

  9. Photon Attenuation and Pair Creation in Highly-Magnetized Pulsars

    CERN Document Server

    Baring, M G; Baring, Matthew G.; Harding, Alice K.

    1999-01-01

    Developments over the last couple of years have supported the interpretation that anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs) possess unusually high magnetic fields, and furthermore may represent a class or classes of neutron stars distinct from the population of conventional radio pulsars. We have recently suggested that such a dichotomization of the pulsar population may naturally arise due to the inherently different conditions in subcritical and supercritical magnetic fields. In this paper, we summarize, within the polar gap model, expectations for observable properties of highly magnetized pulsars, conventional or anomalous. This includes a discussion of the potential suppression of pair production and cascade generation in very strong fields by photon splitting and by threshold pair creation, which might explain radio quiescence in AXPs and SGRs. X-ray and hard gamma-ray spectral properties and trends are identified, with a view to establishing goals for future high energy experimenta...

  10. LDRD ER Final Report: Recreating Planetary Cores in the Laboratory: New Techniques to Extremely High Density States

    Energy Technology Data Exchange (ETDEWEB)

    Collins, G; Celliers, P; Hicks, D; Cauble, R; Bradley, D; MacKinnon, A; Moon, S; Young, D; Chau, R; Eggert, J; Willi, P; Pasley, J; Jeanloz, R; Lee, K; Bennedetti, R; Koenig, M; Benuzzi-Mounaix, A; Batani, D; Loubeyre, P; Hubbard, W

    2003-02-07

    An accurate equation of state (EOS) for planetary constituents at extreme conditions is the key to any credible model of planets or low mass stars. However, very few materials have their high pressure (>few Mbar) EOS experimentally validated, and even then, only on the principal Hugoniot. For planetary and stellar interiors, compression occurs from gravitational force so that material states follow a line of isotropic compression (ignoring phase separation) to ultra-high densities. An example of the hydrogen phase space composing Jupiter and one particular Brown Dwarf is shown. At extreme densities, material states are predicted to have quite unearthly properties such as high temperature superconductivity and low temperature fusion. High density experiments on Earth are achieved with either static compression techniques (i.e. diamond anvil cells) or dynamic compression techniques using large laser facilities, gas guns, or explosives. The ultimate goal of this multi-directorate and multi-institutional proposal was to develop techniques that will enable us to understand material states that previously only existed at the core of giant planets, stars, or speculative theories. Our effort was a complete success, meeting all of the objectives set out in our proposals. First we focused on developing accurate Hugoniot techniques to be used for constraining the equation of state at high pressure/temperature. We mapped out an accurate water EOS and measured that the ionic->electronic conduction transition occurs at lower pressures than models predict. These data and their impact are fully described in the first enclosed paper ''The Equation of State and Optical Properties of Water Compressed by Strong Shock Waves.'' Currently models used to construct planetary isentropes are constrained by only the planet radius, outer atmospheric spectroscopy, and space probe gravitational moment and magnetic field data. Thus these data, which provide rigid constraints

  11. Measurements and identifications of extreme ultraviolet spectra of highly-charged Sm and Er

    CERN Document Server

    Podpaly, Y A; Reader, J; Ralchenko, Yu

    2014-01-01

    We report spectroscopic measurements of highly charged samarium and erbium performed at the National Institute of Standards and Technology (NIST) Electron Beam Ion Trap (EBIT). These measurements are in the extreme ultraviolet (EUV) range, and span electron beam energies from 0.98 keV to 3.00 keV. We observed 71 lines from Kr-like Sm$^{26+}$ to Ni-like Sm$^{34+}$, connecting 83 energy levels, and 64 lines from Rb-like Er$^{32+}$ to Ni-like Er$^{40+}$, connecting 78 energy levels. Of these lines, 64 in Sm and 60 in Er are new. Line identifications are performed using collisional-radiative modeling of the EBIT plasma. All spectral lines are assigned individual uncertainties, most in the $\\sim$0.001 nm range. Energy levels are derived from the wavelength measurements.

  12. High-Resolution Spectroscopy of G191-B2B in the Extreme Ultraviolet

    CERN Document Server

    Cruddace, R G; Yentis, D J; Brown, C M; Gursky, H; Barstow, M A; Bannister, N P; Fraser, G W; Spragg, J E; Lapington, J S; Tandy, J A; Sanderson, B; Culhane, J L; Barbee, T W; Kordas, J F; Goldstein, W H; Fritz, G G

    2001-01-01

    We report a high-resolution (R=3000-4000) spectroscopic observation of the DA white dwarf G191-B2B in the extreme ultraviolet band 220-245 A. A low- density ionised He component is clearly present along the line-of-sight, which if completely interstellar implies a He ionisation fraction considerably higher than is typical of the local interstellar medium. However, some of this material may be associated with circumstellar gas, which has been detected by analysis of the C IV absorption line doublet in an HST STIS spectrum. A stellar atmosphere model assuming a uniform element distribution yields a best fit to the data which includes a significant abundance of photospheric He. The 99-percent confidence contour for the fit parameters excludes solutions in which photospheric He is absent, but this result needs to be tested using models allowing abundance gradients.

  13. Nano-materials for adhesive-free adsorbers for bakable extreme high vacuum cryopump surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Stutzman, Marcy; Jordan, Kevin; Whitney, Roy R.

    2016-10-11

    A cryosorber panel having nanomaterials used for the cryosorption material, with nanomaterial either grown directly on the cryopanel or freestanding nanomaterials attached to the cryopanel mechanically without the use of adhesives. Such nanomaterial cryosorber materials can be used in place of conventional charcoals that are attached to cryosorber panels with special low outgassing, low temperature capable adhesives. Carbon nanotubes and other nanomaterials could serve the same purpose as conventional charcoal cryosorbers, providing a large surface area for cryosorption without the need for adhesive since the nanomaterials can be grown directly on a metallic substrate or mechanically attached. The nanomaterials would be capable of being fully baked by heating above 100.degree. C., thereby eliminating water vapor from the system, eliminating adhesives from the system, and allowing a full bake of the system to reduce hydrogen outgassing, with the goal of obtaining extreme high vacuum where the pump can produce pressures below 1.times.10.sup.-12 Torr.

  14. First search for extremely high energy cosmogenic neutrinos with the IceCube Neutrino Observatory

    Science.gov (United States)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Böser, S.; Botner, O.; Bradley, L.; Braun, J.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; Davis, J. C.; de Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kemming, N.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Knops, S.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Krings, T.; Kroll, G.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Lauer, R.; Lehmann, R.; Lennarz, D.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; Matusik, M.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Schatto, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; van Santen, J.; Voigt, B.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, C.; Xu, X. W.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; IceCube Collaboration

    2010-10-01

    We report on the results of the search for extremely-high energy neutrinos with energies above 107GeV obtained with the partially (˜30%) constructed IceCube in 2007. From the absence of signal events in the sample of 242.1 days of effective live time, we derive a 90% C.L. model independent differential upper limit based on the number of signal events per energy decade at E2ϕνe+νμ+ντ≃1.4×10-6GeVcm-2sec⁡-1sr-1 for neutrinos in the energy range from 3×107 to 3×109GeV.

  15. Acclimation to extremely high ammonia levels in continuous biomethanation process and the associated microbial community dynamics

    DEFF Research Database (Denmark)

    Tian, Hailin; Fotidis, Ioannis; Mancini, Enrico

    2017-01-01

    Acclimatized anaerobic communities to high ammonia levels can offer a solution to the ammonia toxicity problem in biogas reactors. In the current study, a stepwise acclimation strategy up to 10 g NH4+-N L−1, was performed in mesophilic (37 ± 1 °C) continuously stirred tank reactors. The reactors...... were co-digesting (20/80 based on volatile solid) cattle slurry and microalgae, a protein-rich, 3rd generation biomass. Throughout the acclimation period, methane production was stable with more than 95% of the uninhibited yield. Next generation 16S rRNA gene sequencing revealed a dramatic microbiome...... change throughout the ammonia acclimation process. Clostridium ultunense, a syntrophic acetate oxidizing bacteria, increased significantly alongside with hydrogenotrophic methanogen Methanoculleus spp., indicating strong hydrogenotrophic methanogenic activity at extreme ammonia levels (>7 g NH4+-N L−1...

  16. High-Temperature Magnetic Bearings for Gas Turbine Engines

    Science.gov (United States)

    1996-01-01

    Magnetic bearings are the subject of a new NASA Lewis Research Center and U.S. Army thrust with significant industry participation, and coordination with other Government agencies. The NASA/Army emphasis is on high-temperature applications for future gas turbine engines. Magnetic bearings could increase the reliability and reduce the weight of these engines by eliminating the lubrication system. They could also increase the DN (diameter of the bearing times rpm) limit on engine speed and allow active vibration cancellation systems to be used--resulting in a more efficient, "more electric" engine. Finally, the Integrated High-Performance Turbine Engine Technology (IHPTET) Program, a joint Department of Defense/industry program, identified a need for a hightemperature (as high as 1200 F) magnetic bearing that could be demonstrated in a phase III engine. This magnetic bearing is similar to an electric motor. It has a laminated rotor and stator made of cobalt steel. Wound around the stator are a series of electrical wire coils that form a series of electric magnets around the circumference. The magnets exert a force on the rotor. A probe senses the position of the rotor, and a feedback controller keeps it in the center of the cavity. The engine rotor, bearings, and case form a flexible structure that contains a large number of modes. The bearing feedback controller, which could cause some of these modes to become unstable, could be adapted to varying flight conditions to minimize seal clearances and monitor the health of the system. Cobalt steel has a curie point greater than 1700 F, and copper wire has a melting point beyond that. Therefore, practical limitations associated with the maximum magnetic field strength in the cobalt steel and the stress in the rotating components limit the temperature to about 1200 F. The objective of this effort is to determine the limits in temperature and speed of a magnetic bearing operating in an engine. Our approach is to use our in

  17. High current density ion beam obtained by a transition to a highly focused state in extremely low-energy region.

    Science.gov (United States)

    Hirano, Y; Kiyama, S; Fujiwara, Y; Koguchi, H; Sakakita, H

    2015-11-01

    A high current density (≈3 mA/cm(2)) hydrogen ion beam source operating in an extremely low-energy region (E(ib) ≈ 150-200 eV) has been realized by using a transition to a highly focused state, where the beam is extracted from the ion source chamber through three concave electrodes with nominal focal lengths of ≈350 mm. The transition occurs when the beam energy exceeds a threshold value between 145 and 170 eV. Low-level hysteresis is observed in the transition when E(ib) is being reduced. The radial profiles of the ion beam current density and the low temperature ion current density can be obtained separately using a Faraday cup with a grid in front. The measured profiles confirm that more than a half of the extracted beam ions reaches the target plate with a good focusing profile with a full width at half maximum of ≈3 cm. Estimation of the particle balances in beam ions, the slow ions, and the electrons indicates the possibility that the secondary electron emission from the target plate and electron impact ionization of hydrogen may play roles as particle sources in this extremely low-energy beam after the compensation of beam ion space charge.

  18. Multiresolution iterative reconstruction in high-resolution extremity cone-beam CT

    Science.gov (United States)

    Cao, Qian; Zbijewski, Wojciech; Sisniega, Alejandro; Yorkston, John; Siewerdsen, Jeffrey H.; Webster Stayman, J.

    2016-10-01

    Application of model-based iterative reconstruction (MBIR) to high resolution cone-beam CT (CBCT) is computationally challenging because of the very fine discretization (voxel size  <100 µm) of the reconstructed volume. Moreover, standard MBIR techniques require that the complete transaxial support for the acquired projections is reconstructed, thus precluding acceleration by restricting the reconstruction to a region-of-interest. To reduce the computational burden of high resolution MBIR, we propose a multiresolution penalized-weighted least squares (PWLS) algorithm, where the volume is parameterized as a union of fine and coarse voxel grids as well as selective binning of detector pixels. We introduce a penalty function designed to regularize across the boundaries between the two grids. The algorithm was evaluated in simulation studies emulating an extremity CBCT system and in a physical study on a test-bench. Artifacts arising from the mismatched discretization of the fine and coarse sub-volumes were investigated. The fine grid region was parameterized using 0.15 mm voxels and the voxel size in the coarse grid region was varied by changing a downsampling factor. No significant artifacts were found in either of the regions for downsampling factors of up to 4×. For a typical extremities CBCT volume size, this downsampling corresponds to an acceleration of the reconstruction that is more than five times faster than a brute force solution that applies fine voxel parameterization to the entire volume. For certain configurations of the coarse and fine grid regions, in particular when the boundary between the regions does not cross high attenuation gradients, downsampling factors as high as 10×  can be used without introducing artifacts, yielding a ~50×  speedup in PWLS. The proposed multiresolution algorithm significantly reduces the computational burden of high resolution iterative CBCT reconstruction and can be extended to other applications of

  19. High Temperature Magnetics for Power Conversion

    Science.gov (United States)

    2005-06-01

    complex zig zag cutout shown earlier. On the secondary, 3 layers at a time were folded. Folds alternated in direction to even out overall foil...ingredients were mixed in a high-shear blender, calcined at 900°C in air, and ground in a stirred ball mill for 2 hours to an average particle size of...approximately 1 micron. Various organic binders and dispersants were added at the milling step to enhance particle size reduction and improve pressing

  20. Safe epoxy encapsulant for high voltage magnetics

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, R.O.; Archer, W.E.

    1998-01-01

    This paper describes the use of Formula 456, an aliphatic amine cured epoxy for impregnating coils and high voltage transformers. Sandia has evaluated a number of MDA-free epoxy encapsulants which relied on either anhydride or other aromatic amine curing agents. The use of aliphatic amine curing agents was more recently evaluated and has resulted in the definition of Formula 456 resin. Methylene dianiline (MDA) has been used for more than 20 years as the curing agent for various epoxy formulations throughout the Department of Energy and much of industry. Sandia National Laboratories began the process of replacing MDA with other formulations because of regulations imposed by OSHA on the use of MDA. OSHA has regulated MDA because it is a suspect carcinogen. Typically the elimination of OSHA-regulated materials provides a rare opportunity to qualify new formulations in a range of demanding applications. It was important to take full advantage of that opportunity, although the associated materials qualification effort was costly. Small high voltage transformers are one of those demanding applications. The successful implementation of the new formulation for high reliability transformers will be described. The test results that demonstrate the parts are qualified for use in DOE weapon systems will be presented.

  1. Methods of high current magnetic field generator for transcranial magnetic stimulation application

    Science.gov (United States)

    Bouda, N. R.; Pritchard, J.; Weber, R. J.; Mina, M.

    2015-05-01

    This paper describes the design procedures and underlying concepts of a novel High Current Magnetic Field Generator (HCMFG) with adjustable pulse width for transcranial magnetic stimulation applications. This is achieved by utilizing two different switching devices, the MOSFET and insulated gate bipolar transistor (IGBT). Results indicate that currents as high as ±1200 A can be generated with inputs of +/-20 V. Special attention to tradeoffs between field generators utilizing IGBT circuits (HCMFG1) and MOSFET circuits (HCMFG2) was considered. The theory of operation, design, experimental results, and electronic setup are presented and analyzed.

  2. Methods of high current magnetic field generator for transcranial magnetic stimulation application

    Energy Technology Data Exchange (ETDEWEB)

    Bouda, N. R., E-mail: nybouda@iastate.edu; Pritchard, J.; Weber, R. J.; Mina, M. [Department of Electrical and Computer engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2015-05-07

    This paper describes the design procedures and underlying concepts of a novel High Current Magnetic Field Generator (HCMFG) with adjustable pulse width for transcranial magnetic stimulation applications. This is achieved by utilizing two different switching devices, the MOSFET and insulated gate bipolar transistor (IGBT). Results indicate that currents as high as ±1200 A can be generated with inputs of +/−20 V. Special attention to tradeoffs between field generators utilizing IGBT circuits (HCMFG{sub 1}) and MOSFET circuits (HCMFG{sub 2}) was considered. The theory of operation, design, experimental results, and electronic setup are presented and analyzed.

  3. Miniature high speed compressor having embedded permanent magnet motor

    Science.gov (United States)

    Zhou, Lei (Inventor); Zheng, Liping (Inventor); Chow, Louis (Inventor); Kapat, Jayanta S. (Inventor); Wu, Thomas X. (Inventor); Kota, Krishna M. (Inventor); Li, Xiaoyi (Inventor); Acharya, Dipjyoti (Inventor)

    2011-01-01

    A high speed centrifugal compressor for compressing fluids includes a permanent magnet synchronous motor (PMSM) having a hollow shaft, the being supported on its ends by ball bearing supports. A permanent magnet core is embedded inside the shaft. A stator with a winding is located radially outward of the shaft. The PMSM includes a rotor including at least one impeller secured to the shaft or integrated with the shaft as a single piece. The rotor is a high rigidity rotor providing a bending mode speed of at least 100,000 RPM which advantageously permits implementation of relatively low-cost ball bearing supports.

  4. Quasi permanent superconducting magnet of very high field

    Science.gov (United States)

    Ren, Y.; Liu, J.; Weinstein, R.; Chen, I. G.; Parks, D.; Xu, J.; Obot, V.; Foster, C.

    1993-01-01

    We report on persistent field in a quasi-permanent magnet made of high temperature superconductor. The material has an average of 40 percent molar excess of Y, relative to Y1Ba2Cu3O7 and has been irradiated with high energy light ions at 200 MeV. The magnet, which traps 1.52 T at 77.3 K, traps nearly 4 T at 64.5 K. No evidence of giant flux jump or sample cracking was observed.

  5. Droplet-based, high-brightness extreme ultraviolet laser plasma source for metrology

    Science.gov (United States)

    Vinokhodov, A. Yu.; Krivokorytov, M. S.; Sidelnikov, Yu. V.; Krivtsun, V. M.; Medvedev, V. V.; Koshelev, K. N.

    2016-10-01

    We report on the development of a high brightness source of extreme ultraviolet radiation (EUV) with a working wavelength of 13.5 nm. The source is based on a laser-produced plasma driven by pulsed radiation of a Nd:YAG laser system. Liquid droplets of Sn-In eutectic alloy were used as the source fuel. The droplets were created by a droplet generator operating in the jet break-up regime. The EUV emission properties of the plasma, including the emission spectrum, time profile, and conversion efficiency of laser radiation into useful 13.5 nm photons, have been characterized. Using the shadowgraphy technique, we demonstrated the production of corpuscular debris by the plasma source and the influence of the plasma on the neighboring droplet targets. The high-frequency laser operation was simulated by usage of the dual pulse regime. Based on the experimental results, we discuss the physical phenomena that could affect the source operation at high repetition rates. Finally, we estimate that an average source brightness of 1.2 kW/mm2 sr is feasible at a high repetition rate.

  6. Benchmark analysis on diabetics at high risk for lower extremity amputation.

    Science.gov (United States)

    Pinzur, M S; Stuck, R; Sage, R; Pocius, L; Trout, B; Wolf, B; Vrbos, L

    1996-11-01

    After the 1990 establishment of a multidisciplinary foot salvage clinic, 1346 diabetic patients, at high risk for the development of foot ulcers and eventual lower limb amputation, were followed for 4 years. Of the 224 high-risk patients admitted to the hospital, 74 amputations (5.5%) of all or part of a lower limb were performed. Patients undergoing amputation were younger, more severely ill, and required more frequent hospitalizations because of greater organ system involvement. They were also more likely to be institutionalized after discharge. Overall, patients with long-standing adult-onset diabetes, identified as at high risk for foot ulcer development, have a substantially increased risk for lower limb amputation, multiple organ system failure, hospitalization, and institutionalization than do diabetic patients as a whole. Clinical benchmarking facilitates the identification and reduction of unnecessary variations in patient care practices. Here, a formal benchmark analysis provides the current outcome expectations for amputation rates and co-morbidities in patients with diabetes who are classified as at high risk for lower extremity amputation. Management of these patients in a structured, multidisciplinary foot salvage clinic, augmentation of baseline services, and preliminary benchmark data may provide a standard for the measurement of therapeutic interventions that improve patient care.

  7. High-Performance Permanent Magnets for Energy-Efficient Devices

    Science.gov (United States)

    Hadjipanayis, George

    2012-02-01

    Permanent magnets (PMs) are indispensable for many commercial applications including the electric, electronic and automobile industries, communications, information technologies and automatic control engineering. In most of these applications, an increase in the magnetic energy density of the PM, usually presented via the maximum energy product (BH)max, immediately increases the efficiency of the whole device and makes it smaller and lighter. Worldwide demand for high performance permanent magnets has increased dramatically in the past few years driven by hybrid and electric cars, wind turbines and other power generation systems. New energy challenges in the world require devices with higher energy efficiency and minimum environmental impact. The potential of 3d-4f compounds which revolutionized the PM science and technology is almost fully utilized, and the supply of 4f rare earth elements does not seem to be much longer assured. This talk will address the major principles guiding the development of PMs and overview state-of-the-art theoretical and experimental research. Recent progress in the development of nanocomposite PMs, consisting of a fine (at the scale of the magnetic exchange length) mixture of phases with high magnetization and large magnetic hardness will be discussed. Fabrication of such PMs is currently the most promising way to boost the (BH)max, while simultaneously decreasing, at least partially, the reliance on the rare earth elements. Special attention will be paid to the impact which the next-generation high-(BH)max magnets is expected to have on existing and proposed energy-saving technologies.

  8. Micro-Hall magnetic sensors with high magnetic sensitivity based on III-V heterostructures

    Science.gov (United States)

    Del Medico, S.; Benyattou, Taha; Guillot, Gerard; Venet, T.; Gendry, Michel; Tardy, Jacques; Chovet, Alain

    1996-04-01

    In this work, we propose solutions based on engineering of III-V heterostructures to develop new types of semiconductor magnetic sensors. These micro-Hall sensors use the properties of a 2D electron gas and the benefit of pseudomorphic material, in which both the alloy composition and the built-in strain offer additional degrees of freedom for band structure tailoring, to exhibit high magnetic sensitivity, good linearity, low temperature coefficient and high resolution. With the growth optimization which is described, two pseudomorphic In0.75Ga0.25As/In0.52Al0.48As heterostructures were grown on a semi- insulating InP substrate by molecular beam epitaxy. To understand better the influence of the heterostructure design on its electronic properties, a model involving the self-consistent solution of the Poisson and Schrodinger equations using the Fermi-Dirac statistics has been developed. These results have been used to optimize the structure design. A magnetic sensitivity of 346 V/AT with a temperature coefficient of -230 ppm/ degree(s)C between -80 degree(s)C and 85 degree(s)C has been obtained. The device show good linearity against magnetic field and also against the supply current. High signal-to-noise ratios corresponding to minimal magnetic field of 350 nT/Hz1/2 at 100 Hz and 120 nT/Hz1/2 at 1 kHz have been measured.

  9. Simultaneous measurement of magnetization and magnetostriction in 50 T pulsed high magnetic fields.

    Science.gov (United States)

    Doerr, M; Lorenz, W; Neupert, T; Loewenhaupt, M; Kozlova, N V; Freudenberger, J; Bartkowiak, M; Kampert, E; Rotter, M

    2008-06-01

    To simultaneously perform magnetization and magnetostriction measurements in high magnetic fields, a miniaturized device was developed that combines an inductive magnetometer with a capacitive dilatometer and, therefore, it is called "dilamagmeter." This combination of magnetic and magnetoelastic investigations is a new step to a complex understanding of solid state properties. The whole system can be mounted in a 12 mm clear bore of any cryostat usually used in nondestructive pulsed high field magnets. The sensitivity of both methods is about 10(-5) A m(2) for magnetization and 10(-5) relative changes in length for striction measurements. Measurements on a GdSi single crystal, which are corrected by the background signal of the experimental setup, agree well with the results of steady field experiments. All test measurements, which are up until now performed in the temperature range of 4-100 K, confirm the perfect usability and high stability in pulsed fields up to 50 T with a pulse duration of 10 ms.

  10. Magnetic separation using high-T sub c superconductors

    CERN Document Server

    Bolt, L

    2001-01-01

    sensitivity of the high-T sub c material to magnetic fields. Finite elements modelling of the system has provided the framework for the quantitative analysis of the magnetic field distributions on the coil windings and the optimisation of the system configuration. The performance of the separator has been tested at 77 K with liquid nitrogen at atmospheric pressure, and at a temperature approx = 67 K by pumping liquid nitrogen at a pressure around 100 Torr. The highest field obtained in the air gap at 67 K was of 340 mT. Magnetic separators with an iron circuit have been in operation for many years in mineral industry, and there appear to be an opportunity of building machines with high-T sub c coils or retrofitting existing machines with high-T sub c coils to run them closer to saturation in a cheap and effective way. Superconductivity has found in magnetic separation one of its major industrial applications second only to magnetic resonance imaging. Low-T sub c superconducting coils have been employed in Hig...

  11. High performance of low cost soft magnetic materials

    Indian Academy of Sciences (India)

    Josefina M Silveyra; Emília Illeková; Marco Coïsson; Federica Celegato; Franco Vinai; Paola Tiberto; Javier A Moya; Victoria J Cremaschi

    2011-12-01

    The consistent interest in supporting research and development of magnetic materials during the last century is revealed in their steadily increasing market. In this work, the soft magnetic nanocrystalline FINEMET alloy was prepared with commercial purity raw materials and compared for the first time with the generally studied high purity one. The exhaustive characterization covers several diverse techniques: X-ray diffraction, Mössbauer spectroscopy, differential scanning calorimetry, differential thermal analysis and magnetic properties. In addition, a brief economic analysis is presented. For the alloys annealed at 813 K, the value of the grain size was 16 nm with 19.5% of Si, the coercivity was 0.30 A m-1 while the saturation was 1.2 T. These results prove that structural, magnetic and thermal properties of this material are very close to the expensive high purity FINEMET alloy, while a cost reduction of almost 98% seems highly attractive for laboratories and industry. The analysis should be useful not only for the production of FINEMETs, but for other type of systems with similar constitutive elements as well, including soft and hard magnetic materials.

  12. High Speed Operation and Testing of a Fault Tolerant Magnetic Bearing

    Science.gov (United States)

    DeWitt, Kenneth; Clark, Daniel

    2004-01-01

    Research activities undertaken to upgrade the fault-tolerant facility, continue testing high-speed fault-tolerant operation, and assist in the commission of the high temperature (1000 degrees F) thrust magnetic bearing as described. The fault-tolerant magnetic bearing test facility was upgraded to operate to 40,000 RPM. The necessary upgrades included new state-of-the art position sensors with high frequency modulation and new power edge filtering of amplifier outputs. A comparison study of the new sensors and the previous system was done as well as a noise assessment of the sensor-to-controller signals. Also a comparison study of power edge filtering for amplifier-to-actuator signals was done; this information is valuable for all position sensing and motor actuation applications. After these facility upgrades were completed, the rig is believed to have capabilities for 40,000 RPM operation, though this has yet to be demonstrated. Other upgrades included verification and upgrading of safety shielding, and upgrading control algorithms. The rig will now also be used to demonstrate motoring capabilities and control algorithms are in the process of being created. Recently an extreme temperature thrust magnetic bearing was designed from the ground up. The thrust bearing was designed to fit within the existing high temperature facility. The retrofit began near the end of the summer, 04, and continues currently. Contract staff authored a NASA-TM entitled "An Overview of Magnetic Bearing Technology for Gas Turbine Engines", containing a compilation of bearing data as it pertains to operation in the regime of the gas turbine engine and a presentation of how magnetic bearings can become a viable candidate for use in future engine technology.

  13. Use of High Magnetic Field to Control Microstructural Evolution in Metallic and Magnetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ludtka, G.M.; Mackiewicz- Ludtka, G.; Wilgen, J.B.; Kisner, R.A.

    2010-06-27

    The Amendment 1, referred to as Phase 2, to the original CRADA NFE-06-00414 added tasks 3 through 7 to the original statement of work that had two main tasks that were successfully accomplished in Phase 1 of this project. In this Phase 2 CRADA extension, extensive research and development activities were conducted using high magnetic field processing effects for the purpose of manipulating microstructure in the SAE 5160 steel to refine grain size isothermally and to develop nanocrystalline spacing pearlite during continuous cooling, and to enhance the formability/forgability of the non-ferrous precipitation hardening magnesium alloy AZ90 by applying a high magnetic field during deformation processing to investigate potential magnetoplasticity in this material. Significant experimental issues (especially non-isothermal conditions evolving upon insertion of an isothermal sample in the high magnetic field) were encountered in the isothermal phase transformation reversal experiments (Task 4) that later were determined to be due to various condensed matter physics phenomenon such as the magnetocaloric (MCE) effect that occurs in the vicinity of a materials Curie temperature. Similarly the experimental deformation rig had components for monitoring deformation/strain (Task 3) that were susceptible to the high magnetic field of the ORNL Thermomagnetic Processing facility 9-T superconducting magnet that caused electronic components to fail or record erroneous (very noisy) signals. Limited experiments on developing nanocrystalline spacing pearlite were not sufficient to elucidate the impact of high magnetic field processing on the final pearlite spacing since significant statistical evaluation of many pearlite colonies would need to be done to be conclusive. Since extensive effort was devoted to resolving issues for Tasks 3 and 7, only results for these focused activities are included in this final CRADA report along with those for Task 7 (described in the Objectives Section

  14. High-throughput search for new permanent magnet materials.

    Science.gov (United States)

    Goll, D; Loeffler, R; Herbst, J; Karimi, R; Schneider, G

    2014-02-12

    The currently highest-performance Fe-Nd-B magnets show limited cost-effectiveness and lifetime due to their rare-earth (RE) content. The demand for novel hard magnetic phases with more widely available RE metals, reduced RE content or, even better, completely free of RE metals is therefore tremendous. The chances are that such materials still exist given the large number of as yet unexplored alloy systems. To discover such phases, an elaborate concept is necessary which can restrict and prioritize the search field while making use of efficient synthesis and analysis methods. It is shown that an efficient synthesis of new phases using heterogeneous non-equilibrium diffusion couples and reaction sintering is possible. Quantitative microstructure analysis of the domain pattern of the hard magnetic phases can be used to estimate the intrinsic magnetic parameters (saturation polarization from the domain contrast, anisotropy constant from the domain width, Curie temperature from the temperature dependence of the domain contrast). The probability of detecting TM-rich phases for a given system is high, therefore the approach enables one to scan through even higher component systems with one single sample. The visualization of newly occurring hard magnetic phases via their typical domain structure and the correlation existing between domain structure and intrinsic magnetic properties allows an evaluation of the industrial relevance of these novel phases.

  15. High gradient magnetic field microstructures for magnetophoretic cell separation.

    Science.gov (United States)

    Abdel Fattah, Abdel Rahman; Ghosh, Suvojit; Puri, Ishwar K

    2016-08-01

    Microfluidics has advanced magnetic blood fractionation by making integrated miniature devices possible. A ferromagnetic microstructure array that is integrated with a microfluidic channel rearranges an applied magnetic field to create a high gradient magnetic field (HGMF). By leveraging the differential magnetic susceptibilities of cell types contained in a host medium, such as paramagnetic red blood cells (RBCs) and diamagnetic white blood cells (WBCs), the resulting HGMF can be used to continuously separate them without attaching additional labels, such as magnetic beads, to them. We describe the effect of these ferromagnetic microstructure geometries have on the blood separation efficacy by numerically simulating the influence of microstructure height and pitch on the HGMF characteristics and resulting RBC separation. Visualizations of RBC trajectories provide insight into how arrays can be optimized to best separate these cells from a host fluid. Periodic microstructures are shown to moderate the applied field due to magnetic interference between the adjacent teeth of an array. Since continuous microstructures do not similarly weaken the resultant HGMF, they facilitate significantly higher RBC separation. Nevertheless, periodic arrays are more appropriate for relatively deep microchannels since, unlike continuous microstructures, their separation effectiveness is independent of depth. The results are relevant to the design of microfluidic devices that leverage HGMFs to fractionate blood by separating RBCs and WBCs.

  16. Exposure assessment of arc welders to extremely low frequency magnetic field: its relationship with the secretion of paratormone hormone and mood states

    Directory of Open Access Journals (Sweden)

    Roohalah Hajizadeh

    2016-09-01

    Full Text Available Introduction: Nowadays, exposure to extremely low frequency (ELF magnetic field has been interested in many studies due to possible effects on human physical-mental health. Therefore, this study aimed to assess arc welders’ exposure to extremely low frequency magnetic field and to determine its relationship with the secretion of paratormone (PTH hormone and mood states. Material and Method: The present study has been conducted among 35 healthy production workers (as exposed group and 35 healthy administrative personnel (as unexposed group. After checking the work activities of participants according to the guide recommended by the National Institute for Occupational Safety and Health (NIOSH, ELF magnetic fields were measured using an ELF measurement device in the regions including trunk, head, and neck. The plasma levels of PTH hormone of both groups were evaluated by the Electrochemiluminescence method. Stress-Arousal Checklist (SACL was used to assess the mode states of subjects in both groups. The collected data were analyzed by SPSS software version 16. Result: There was a significant difference between the exposed and unexposed groups with respect to the exposure level to ELF magnetic fields (P-value<0.0001. Mean PTH hormone level in exposed group (34.54 pg/ml was lower than unexposed ones (37 pg/ml, however these mean values weren’t significantly different (P-value=0.67. Score of “stress” subscale related to the “pleasure” and score of “arousal” subscale  related to the “activities and alertness” in the unexposed group were significantly higher than those in exposed group (p<0.0001. Regarding the relationship between exposure level to ELF electromagnetic field and scores of  stress, arousal, and PTH hormone level in the two groups, it should be stated that only a significant and positive association was found between the average exposure to ELF magnetic fields and PTH levels in the exposed group (P-value<0.009, r=0

  17. High diversity and suggested endemicity of culturable Actinobacteria in an extremely oligotrophic desert oasis

    Directory of Open Access Journals (Sweden)

    Hector Fernando Arocha-Garza

    2017-05-01

    shows that our isolation effort produced 38 unique OTUs in six new monophyletic clades. This high biodiversity and uniqueness of Actinobacteria in an extreme oligotrophic environment, which has previously been reported for its diversity and endemicity, is a suggestive sign of microbial biogeography of Actinobacteria and it also represents an invaluable source of biological material for future ecological and bioprospecting studies.

  18. High diversity and suggested endemicity of culturable Actinobacteria in an extremely oligotrophic desert oasis.

    Science.gov (United States)

    Arocha-Garza, Hector Fernando; Canales-Del Castillo, Ricardo; Eguiarte, Luis E; Souza, Valeria; De la Torre-Zavala, Susana

    2017-01-01

    isolation effort produced 38 unique OTUs in six new monophyletic clades. This high biodiversity and uniqueness of Actinobacteria in an extreme oligotrophic environment, which has previously been reported for its diversity and endemicity, is a suggestive sign of microbial biogeography of Actinobacteria and it also represents an invaluable source of biological material for future ecological and bioprospecting studies.

  19. Quantifying imaging performance bounds of extreme dipole illumination in high NA optical lithography

    Science.gov (United States)

    Lee, Myungjun; Smith, Mark D.; Biafore, John; Graves, Trey; Levy, Ady

    2016-10-01

    We present a framework to analyze the performance of optical imaging in a hyper numerical aperture (NA) immersion lithography scanner. We investigate the method to quantify imaging performance by computing upperand lower-bounds on the threshold normalized image log-slope (NILS) and the depth of focus (DOF) in conjunction with the traditional image quality metrics such as the mask error enhancement factor (MEEF) and the linearity for various different pitches and line to space (LS) duty cycles. The effects of the interaction between the light illumination and the feature size are extensively characterized based on the aerial image (AI) behavior in particular for the extreme dipole illumination that is one of the commonly used off-axis illuminations for sub-100nm logic and memory devices, providing resolution near the physical limit of an optical single patterning step. The proposed aerial imaging-based DOF bounds are compared to the results obtained from an experimentally calibrated resist model, and we observed good agreement. In general, the extreme dipole illumination is only optimal for a single particular pitch, therefore understanding the through-pitch imaging performance bound, which depends on the illumination shape, pattern size, and process conditions, is critically important. We find that overall imaging performance varies depending upon the number of diffracted beams passing through the scanner optics. An even number of beams provides very different trends compared to the results from an odd-number of beams. This significant non-linear behavior occurs in certain pitch regions corresponding to 3 beam interference imaging. In this region the imaging performance and the pattern printability become extremely sensitive to the LS duty cycle. In addition, there is a notable tradeoff between the DOF and the NILS that is observed in the problematic 3-beam region and this tradeoff eventually affects the achievable process window (PW). Given the practical real

  20. Special-Purpose High-Torque Permanent-Magnet Motors

    Science.gov (United States)

    Doane, George B., III

    1995-01-01

    Permanent-magnet brushless motors that must provide high commanded torques and satisfy unusual heat-removal requirement are developed. Intended for use as thrust-vector-control actuators in large rocket engines. Techniques and concepts used to design improved motors for special terrestrial applications. Conceptual motor design calls for use of rotor containing latest high-energy-product rare-earth permanent magnets so that motor produces required torque while drawing smallest possible currents from power supply. Torque generated by electromagnetic interaction between stator and permanent magnets in rotor when associated electronic circuits applied appropriately temporally and spatially phased currents to stator windings. Phase relationships needed to produce commanded torque computed in response to torque command and to electronically sensed angular position of rotor relative to stator.

  1. High-Energy Electron Confinement in a Magnetic Cusp Configuration

    Science.gov (United States)

    Park, Jaeyoung; Krall, Nicholas A.; Sieck, Paul E.; Offermann, Dustin T.; Skillicorn, Michael; Sanchez, Andrew; Davis, Kevin; Alderson, Eric; Lapenta, Giovanni

    2015-04-01

    We report experimental results validating the concept that plasma confinement is enhanced in a magnetic cusp configuration when β (plasma pressure/magnetic field pressure) is of order unity. This enhancement is required for a fusion power reactor based on cusp confinement to be feasible. The magnetic cusp configuration possesses a critical advantage: the plasma is stable to large scale perturbations. However, early work indicated that plasma loss rates in a reactor based on a cusp configuration were too large for net power production. Grad and others theorized that at high β a sharp boundary would form between the plasma and the magnetic field, leading to substantially smaller loss rates. While not able to confirm the details of Grad's work, the current experiment does validate, for the first time, the conjecture that confinement is substantially improved at high β . This represents critical progress toward an understanding of the plasma dynamics in a high-β cusp system. We hope that these results will stimulate a renewed interest in the cusp configuration as a fusion confinement candidate. In addition, the enhanced high-energy electron confinement resolves a key impediment to progress of the Polywell fusion concept, which combines a high-β cusp configuration with electrostatic fusion for a compact, power-producing nuclear fusion reactor.

  2. High-Energy Electron Confinement in a Magnetic Cusp Configuration

    Directory of Open Access Journals (Sweden)

    Jaeyoung Park

    2015-06-01

    Full Text Available We report experimental results validating the concept that plasma confinement is enhanced in a magnetic cusp configuration when β (plasma pressure/magnetic field pressure is of order unity. This enhancement is required for a fusion power reactor based on cusp confinement to be feasible. The magnetic cusp configuration possesses a critical advantage: the plasma is stable to large scale perturbations. However, early work indicated that plasma loss rates in a reactor based on a cusp configuration were too large for net power production. Grad and others theorized that at high β a sharp boundary would form between the plasma and the magnetic field, leading to substantially smaller loss rates. While not able to confirm the details of Grad’s work, the current experiment does validate, for the first time, the conjecture that confinement is substantially improved at high β. This represents critical progress toward an understanding of the plasma dynamics in a high-β cusp system. We hope that these results will stimulate a renewed interest in the cusp configuration as a fusion confinement candidate. In addition, the enhanced high-energy electron confinement resolves a key impediment to progress of the Polywell fusion concept, which combines a high-β cusp configuration with electrostatic fusion for a compact, power-producing nuclear fusion reactor.

  3. The paradox of extreme high-altitude migration in bar-headed geese Anser indicus

    Science.gov (United States)

    Hawkes, L.A.; Balachandran, S.; Batbayar, N.; Butler, P.J.; Chua, B.; Douglas, D.C.; Frappell, P.B.; Hou, Y.; Milsom, W.K.; Newman, S.H.; Prosser, D.J.; Sathiyaselvam, P.; Scott, G.R.; Takekawa, John Y.; Natsagdorj, T.; Wikelski, M.; Witt, M.J.; Yan, B.; Bishop, C.M.

    2012-01-01

    Bar-headed geese are renowned for migratory flights at extremely high altitudes over the world's tallest mountains, the Himalayas, where partial pressure of oxygen is dramatically reduced while flight costs, in terms of rate of oxygen consumption, are greatly increased. Such a mismatch is paradoxical, and it is not clear why geese might fly higher than is absolutely necessary. In addition, direct empirical measurements of high-altitude flight are lacking. We test whether migrating bar-headed geese actually minimize flight altitude and make use of favourable winds to reduce flight costs. By tracking 91 geese, we show that these birds typically travel through the valleys of the Himalayas and not over the summits. We report maximum flight altitudes of 7290 m and 6540 m for southbound and northbound geese, respectively, but with 95 per cent of locations received from less than 5489 m. Geese travelled along a route that was 112 km longer than the great circle (shortest distance) route, with transit ground speeds suggesting that they rarely profited from tailwinds. Bar-headed geese from these eastern populations generally travel only as high as the terrain beneath them dictates and rarely in profitable winds. Nevertheless, their migration represents an enormous challenge in conditions where humans and other mammals are only able to operate at levels well below their sea-level maxima.

  4. The Sedentary Survey of Extreme High Energy Peaked BL Lacs. II. The Catalog and Spectral Properties

    CERN Document Server

    Giommi, P; Perri, M; Padovani, P

    2004-01-01

    The multi-frequency `Sedentary Survey' is a deep, statistically complete, radio flux limited sample comprising 150 BL Lacertae objects distinguished by their extremely high X-ray to radio flux ratio, ranging from five hundred to over five thousand times that of typical BL Lacs discovered in radio surveys. This paper presents the final, 100% identified, catalog together with the optical, X-ray and broad-band SEDs constructed combining literature multi-frequency data with non-simultaneous optical observations and BeppoSAX X-ray data, when available. The SEDs confirm that the peak of the synchrotron power in these objects is located at very high energies. BeppoSAX wide band X-ray observations show that, in most cases, the X-ray spectra are convex and well described by a logarithmic parabola model peaking (in a E f(E) vs E representation) between 0.02 to several keV. Owing to the high synchrotron energies involved most of the sources in the catalog are likely to be TeV emitters, with the closest and brightest one...

  5. Atmospheric and Fog Effects on Ultra-Wide Band Radar Operating at Extremely High Frequencies.

    Science.gov (United States)

    Balal, Nezah; Pinhasi, Gad A; Pinhasi, Yosef

    2016-05-23

    The wide band at extremely high frequencies (EHF) above 30 GHz is applicable for high resolution directive radars, resolving the lack of free frequency bands within the lower part of the electromagnetic spectrum. Utilization of ultra-wideband signals in this EHF band is of interest, since it covers a relatively large spectrum, which is free of users, resulting in better resolution in both the longitudinal and transverse dimensions. Noting that frequencies in the millimeter band are subjected to high atmospheric attenuation and dispersion effects, a study of the degradation in the accuracy and resolution is presented. The fact that solid-state millimeter and sub-millimeter radiation sources are producing low power, the method of continuous-wave wideband frequency modulation becomes the natural technique for remote sensing and detection. Millimeter wave radars are used as complementary sensors for the detection of small radar cross-section objects under bad weather conditions, when small objects cannot be seen by optical cameras and infrared detectors. Theoretical analysis for the propagation of a wide "chirped" Frequency-Modulated Continuous-Wave (FMCW) radar signal in a dielectric medium is presented. It is shown that the frequency-dependent (complex) refractivity of the atmospheric medium causes distortions in the phase of the reflected signal, introducing noticeable errors in the longitudinal distance estimations, and at some frequencies may also degrade the resolution.

  6. A method of batch-purifying microalgae with multiple antibiotics at extremely high concentrations

    Science.gov (United States)

    Han, Jichang; Wang, Song; Zhang, Lin; Yang, Guanpin; Zhao, Lu; Pan, Kehou

    2016-01-01

    Axenic microalgal strains are highly valued in diverse microalgal studies and applications. Antibiotics, alone or in combination, are often used to avoid bacterial contamination during microalgal isolation and culture. In our preliminary trials, we found that many microalgae ceased growing in antibiotics at extremely high concentrations but could resume growth quickly when returned to an antibiotics-free liquid medium and formed colonies when spread on a solid medium. We developed a simple and highly efficient method of obtaining axenic microalgal cultures based on this observation. First, microalgal strains of different species or strains were treated with a mixture of ampicillin, gentamycin sulfate, kanamycin, neomycin and streptomycin (each at a concentration of 600 mg/L) for 3 days; they were then transferred to antibiotics-free medium for 5 days; and finally they were spread on solid f/2 media to allow algal colonies to form. With this method, five strains of Nannochloropsis sp. (Eustigmatophyceae), two strains of Cylindrotheca sp. (Bacillariophyceae), two strains of Tetraselmis sp. (Chlorodendrophyceae) and one strain of Amphikrikos sp. (Trebouxiophyceae) were purified successfully. The method shows promise for batch-purifying microalgal cultures.

  7. A Novel Gravity Compensation Method for High Precision Free-INS Based on "Extreme Learning Machine".

    Science.gov (United States)

    Zhou, Xiao; Yang, Gongliu; Cai, Qingzhong; Wang, Jing

    2016-11-29

    In recent years, with the emergency of high precision inertial sensors (accelerometers and gyros), gravity compensation has become a major source influencing the navigation accuracy in inertial navigation systems (INS), especially for high-precision INS. This paper presents preliminary results concerning the effect of gravity disturbance on INS. Meanwhile, this paper proposes a novel gravity compensation method for high-precision INS, which estimates the gravity disturbance on the track using the extreme learning machine (ELM) method based on measured gravity data on the geoid and processes the gravity disturbance to the height where INS has an upward continuation, then compensates the obtained gravity disturbance into the error equations of INS to restrain the INS error propagation. The estimation accuracy of the gravity disturbance data is verified by numerical tests. The root mean square error (RMSE) of the ELM estimation method can be improved by 23% and 44% compared with the bilinear interpolation method in plain and mountain areas, respectively. To further validate the proposed gravity compensation method, field experiments with an experimental vehicle were carried out in two regions. Test 1 was carried out in a plain area and Test 2 in a mountain area. The field experiment results also prove that the proposed gravity compensation method can significantly improve the positioning accuracy. During the 2-h field experiments, the positioning accuracy can be improved by 13% and 29% respectively, in Tests 1 and 2, when the navigation scheme is compensated by the proposed gravity compensation method.

  8. Development of high temperature superconductors for magnetic field applications

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, D.C.

    1991-12-31

    The key requirement for magnetic field applications of high temperature superconductor (HTS) materials is to have conductors with high transport critical current density available for magnet builders. After 3 or 4 years of being without any such object, conductor makers have had recent success in producing simple conductor prototypes. These have permitted the construction of simple HTS magnets having self fields exceeding 1 tesla at 4K. Thus the scientific feasibility of making powerful HTS magnets has been demonstrated. Attention to the technological aspects of making HTS conductors for magnets with strong flux pinning and reduced superconducting granularity is now sensible and attractive. However, extrinsic defects such as filament sausaging, cracking, misaligned grains and other perturbation to long range current flow must be controlled at a low level if the benefit of intrinsic improvements to the critical current density is to be maintained in the conductor form. Due to the great complexity of the HTS materials, there is sometimes confusion as to whether a given sample has an intrinsically or extrinsically limited critical current density. Systematic microstructure variation experiments and resistive transition analysis are shown to be particularly helpful in this phase of conductor development.

  9. Development of high temperature superconductors for magnetic field applications

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, D.C.

    1991-01-01

    The key requirement for magnetic field applications of high temperature superconductor (HTS) materials is to have conductors with high transport critical current density available for magnet builders. After 3 or 4 years of being without any such object, conductor makers have had recent success in producing simple conductor prototypes. These have permitted the construction of simple HTS magnets having self fields exceeding 1 tesla at 4K. Thus the scientific feasibility of making powerful HTS magnets has been demonstrated. Attention to the technological aspects of making HTS conductors for magnets with strong flux pinning and reduced superconducting granularity is now sensible and attractive. However, extrinsic defects such as filament sausaging, cracking, misaligned grains and other perturbation to long range current flow must be controlled at a low level if the benefit of intrinsic improvements to the critical current density is to be maintained in the conductor form. Due to the great complexity of the HTS materials, there is sometimes confusion as to whether a given sample has an intrinsically or extrinsically limited critical current density. Systematic microstructure variation experiments and resistive transition analysis are shown to be particularly helpful in this phase of conductor development.

  10. Scaling and Intensification of Extreme Precipitation in High-Resolution Climate Change Simulations

    Science.gov (United States)

    Ban, Nikolina; Leutwyler, David; Lüthi, Daniel; Schär, Christoph

    2017-04-01

    Climate change projections of extreme precipitation are of great interest due to hydrological impacts such as droughts, floods, erosion, landslides and debris flows. Despite the trend towards dryer conditions over Europe, many climate simulations project increases of heavy precipitation events, while some theoretical studies have raised the possibility of dramatic increases in hourly events (by up to 14% per degree warming). However, conventional climate models are not suited to assess short-term heavy events due to the need to parameterize deep convection. High-resolution climate models with kilometer-scale grid spacing at which parameterization of convection can be switched off, significantly improve the simulation of heavy precipitation and can alter the climate change signal (e.g., Ban et al., 2015). Here we present decade-long high-resolution climate change simulations at horizontal resolution of 2.2 km over Europe on a computational domain with 1536x1536x60 grid points. These simulations have become feasible with a new version of the COSMO model that runs entirely on Graphics Processing Units. We compare a present-day climate simulation, driven by ERA-Interim reanalysis (Leutwyler at al., 2016), with a Pseudo-Global Warming (PGW) simulation The PGW simulation is driven by the slowly evolving mean seasonal cycle of the climate changes (derived from the CMIP5 model), superimposed on the ERA-Interim reanalysis. With this approach, the resulting changes are due to large scale warming of the atmosphere and due to slow-varying circulation changes. We will present the differences in climate change signal between conventional and high-resolution climate models, and discuss the thermodynamic effects on intensification of extreme precipitation. Ban N., J. Schmidli and C. Schär, 2015: Heavy precipitation in a changing climate: Does short-term summer precipitation increase faster? Geophys. Res. Lett., 42 (4), 1165-1172 Leutwyler, D., D. Lüthi, N. Ban, O. Fuhrer and C

  11. Magnetic flux annihilation waves in inhomogeneous high-temperature superconductors

    NARCIS (Netherlands)

    Rudnev, IA; Khodot, AE; Eremin, AV; Mikhailov, BP

    2004-01-01

    The process of magnetic field penetration into polycrystalline high-T-c superconductors of the YBa2Cu3O7 - x and Bi2Sr2Ca2Cu3O10 - x systems has been studied using traditional magnetooptical methods and scanning Hall probe microscopy. It is established that remagnetization of a sample is accompanied

  12. Survey of high field superconducting material for accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Scahlan, R.; Greene, A.F.; Suenaga, M.

    1986-05-01

    The high field superconductors which could be used in accelerator dipole magnets are surveyed, ranking these candidates with respect to ease of fabrication and cost as well as superconducting properties. Emphasis is on Nb/sub 3/Sn and NbTi. 27 refs., 2 figs. (LEW)

  13. Interaction effects in high density magnetic particulate media

    Energy Technology Data Exchange (ETDEWEB)

    Cerchez, Mihai; Stoleriu, Laurentiu; Stancu, Alexandru

    2004-01-01

    The paper presents a micromagnetic study of the particulate high density recording media. The main difference in the behavior of such a system is the appearance of magnetic clusters which lead to a different behavior of the system. New hypotheses for interpreting such systems are presented.

  14. Characterizing the Chemical Stability of High Temperature Materials for Application in Extreme Environments

    Science.gov (United States)

    Opila, Elizabeth

    2005-01-01

    The chemical stability of high temperature materials must be known for use in the extreme environments of combustion applications. The characterization techniques available at NASA Glenn Research Center vary from fundamental thermodynamic property determination to material durability testing in actual engine environments. In this paper some of the unique techniques and facilities available at NASA Glenn will be reviewed. Multiple cell Knudsen effusion mass spectrometry is used to determine thermodynamic data by sampling gas species formed by reaction or equilibration in a Knudsen cell held in a vacuum. The transpiration technique can also be used to determine thermodynamic data of volatile species but at atmospheric pressures. Thermodynamic data in the Si-O-H(g) system were determined with this technique. Free Jet Sampling Mass Spectrometry can be used to study gas-solid interactions at a pressure of one atmosphere. Volatile Si(OH)4(g) was identified by this mass spectrometry technique. A High Pressure Burner Rig is used to expose high temperature materials in hydrocarbon-fueled combustion environments. Silicon carbide (SiC) volatility rates were measured in the burner rig as a function of total pressure, gas velocity and temperature. Finally, the Research Combustion Lab Rocket Test Cell is used to expose high temperature materials in hydrogen/oxygen rocket engine environments to assess material durability. SiC recession due to rocket engine exposures was measured as a function of oxidant/fuel ratio, temperature, and total pressure. The emphasis of the discussion for all techniques will be placed on experimental factors that must be controlled for accurate acquisition of results and reliable prediction of high temperature material chemical stability.

  15. Quantification of climate change effects on extreme precipitation used for high resolution hydrologic design

    DEFF Research Database (Denmark)

    Arnbjerg-Nielsen, Karsten

    2012-01-01

    Design of urban drainage structures should include the climatic changes anticipated over the technical lifetime of the system. In Northern Europe climate changes implies increasing occurrences of extreme rainfall. Three approaches to quantify the impact of climate changes on extreme rainfall are ...

  16. The change of electric potentials in the oral cavity after application of extremely low frequency pulsed magnetic field

    Directory of Open Access Journals (Sweden)

    Piotr Skomro

    2012-12-01

    Full Text Available Electric potentials occurring in the oral cavity deserve attention as they may cause various diseases and subjective feelings, which are very difficult to treat. The aim of this study was to evaluate the electric potentials within the oral cavity in patients with metal fillings and metal prosthetic restorations, after using a pulsed electromagnetic field. The study was carried out on 84 patients. The Viofor JPS Classic device was used in the treatment. It generates a pulsed electromagnetic field with low induction of the extremely low frequency (ELF range. Average values of electric potentials in the preliminary test were about the same in both groups; they were 148.8 mV and 145.5 mV. After another appliance of ELF fields there was found a steady decline in the average value of electric potentials in the study group. This decrease was statistically highly significant, while mean values of electric potentials in the control group were characterized by a slightly upward tendency. The obtained statistically significant reduction of electric potentials in the oral cavity of patients having metal fillings and metal prosthetic restorations, after application of the Viofor JPS Classic device, implies a huge impact of ELF pulsed electromagnetic field on inhibition of electrochemical processes, as well as on inhibition of dental alloy corrosion. 

  17. The change of electric potentials in the oral cavity after application of extremely low frequency pulsed magnetic field.

    Science.gov (United States)

    Skomro, Piotr; Lietz-Kijak, Danuta; Kijak, Edward; Bogdziewicz-Wałęsa, Olga; Opalko, Krystyna

    2012-12-11

    Electric potentials occurring in the oral cavity deserve attention as they may cause various diseases and subjective feelings, which are very difficult to treat. The aim of this study was to evaluate the electric potentials within the oral cavity in patients with metal fillings and metal prosthetic restorations, after using a pulsed electromagnetic field. The study was carried out on 84 patients. The Viofor JPS Classic device was used in the treatment. It generates a pulsed electromagnetic field with low induction of the extremely low frequency (ELF) range. Average values of electric potentials in the preliminary test were about the same in both groups; they were 148.8 mV and 145.5 mV. After another appliance of ELF fields there was found a steady decline in the average value of electric potentials in the study group. This decrease was statistically highly significant, while mean values of electric potentials in the control group were characterized by a slightly upward tendency. The obtained statistically significant reduction of electric potentials in the oral cavity of patients having metal fillings and metal prosthetic restorations, after application of the Viofor JPS Classic device, implies a huge impact of ELF pulsed electromagnetic field on inhibition of electrochemical processes, as well as on inhibition of dental alloy corrosion. 

  18. Observing Ultra High Energy Cosmic Particles from Space: SEUSO, the Super Extreme Universe Space Observatory Mission

    CERN Document Server

    Santangelo, Andrea

    2009-01-01

    The experimental search for ultra high energy cosmic messengers, from $E\\sim 10^{19}$ eV to beyond $E\\sim 10^{20}$ eV, at the very end of the known energy spectrum, constitutes an extraordinary opportunity to explore a largely unknown aspect of our universe. Key scientific goals are the identification of the sources of ultra high energy particles, the measurement of their spectra and the study of galactic and local intergalactic magnetic fields. Ultra high energy particles might, also, carry evidence of unknown physics or of exotic particles relics of the early universe. To meet this challenge a significant increase in the integrated exposure is required. This implies a new class of experiments with larger acceptances and good understanding of the systematic uncertainties. Space based observatories can reach the instantaneous aperture and the integrated exposure necessary to systematically explore the ultra high energy universe. In this paper, after briefly summarising the science case of the mission, we desc...

  19. The age of extremely red and massive galaxies at very high redshift

    CERN Document Server

    Castro-Rodriguez, N

    2011-01-01

    Aims. We present a determination of the intrinsic colors and ages of galaxies at very high redshift, in particular old galaxies (OGs) within extremely red objects (EROs). To date, the definition of EROs has been restricted to objects with z2.5). We therefore, refer to these objects as very high-redshift EROs (Z-EROS, herein). Methods. We analyze 63,550 galaxies selected in the XMM-LSS field. To obtain a reasonably sized sample of EROs, it is essential to consider a very wide area surveys. We identify targets within an area of 0.77 square degrees for which optical to mid-infrared data are available from SUBARU, UKIDSS, and Spitzer. We select Z-EROs based on their colors, and then perform a selection of only OGs. One of our novel innovations is to adapt the traditional method of EROs selection based on the filters I and K, to higher redshifts. Using our method, we identify 20 objects that satisfy the conditions required to be Z-EROs/OGs at redshifts 2.5~4.7. After including additional galaxies with z<2.5 ana...

  20. The use of bone allografts for limb salvage in high-grade extremity osteosarcoma.

    Science.gov (United States)

    Gebhardt, M C; Flugstad, D I; Springfield, D S; Mankin, H J

    1991-09-01

    Limb preservation is increasingly being employed in the local treatment of high-grade extremity osteosarcoma. Bone allografts used to reconstruct the bony defects following tumor resection offer many advantages, including joint reconstruction and incorporation of the graft to the host bone in these relatively young patients. The results of 53 patients 30 years of age or younger were assessed to determine functional outcome. Fresh-frozen allografts were employed as osteoarticular grafts, allograft-arthrodeses, allograft-prosthesis composites, or intercalary grafts. Follow-up intervals averaged 25 months (range, two to 63 months). Life-table analysis showed that the probability of a satisfactory functional result was 73% if local tumor recurrences were excluded. Complications included 16 infections, six fractures, 12 nonunions, and six unstable joints. There were five local recurrences. Eighteen grafts ultimately failed, and in six patients, this resulted in an above-knee amputation. An additional five received a second graft. The functional "end results" of the 38 patients with two or more years of follow-up examinations were 70% satisfactory in those without a local recurrence. There was no statistically significant difference in functional outcome or local or distant relapse in those patients receiving preoperative chemotherapy. The authors conclude that allografts can be used for limb reconstruction in patients with high-grade osteosarcoma who receive aggressive adjuvant chemotherapy. The functional results are comparable to other methods of reconstruction, and once incorporated by the host, offer the advantage of longevity, compared with metallic implants.

  1. Microsystem for remote sensing of high energy radiation with associated extremely low photon flux densities

    Science.gov (United States)

    Otten, A.; Jain, V. K.

    2015-08-01

    This paper presents a microsystem for remote sensing of high energy radiation in extremely low flux density conditions. With wide deployment in mind, potential applications range from nuclear non-proliferation, to hospital radiation-safety. The daunting challenge is the low level of photon flux densities - emerging from a Scintillation Crystal (SC) on to a ~1 mm-square detector, which are a factor of 10000 or so lower than those acceptable to recently reported photonic chips (including `single-photon detection' chips), due to a combination of low Lux, small detector size, and short duration SC output pulses - on the order of 1 μs. These challenges are attempted to be overcome by the design of an innovative `System on a Chip' type microchip, with high detector sensitivity, and effective coupling from the SC to the photodetector. The microchip houses a tiny n+ diff p-epi photodiode (PD) as well as the associated analog amplification and other related circuitry, all fabricated in 0.5micron, 3-metal 2-poly CMOS technology. The amplification, together with pulse-shaping of the photocurrent-induced voltage signal, is achieved through a tandem of two capacitively coupled, double-cascode amplifiers. Included in the paper are theoretical estimates and experimental results.

  2. Significant mobility enhancement in extremely thin highly doped ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Look, David C., E-mail: david.look@wright.edu [Semiconductor Research Center, Wright State University, 3640 Colonel Glenn Hwy., Dayton, Ohio 45435 (United States); Wyle Laboratories, Inc., 2601 Mission Point Blvd., Dayton, Ohio 45431 (United States); Air Force Research Laboratory Sensors Directorate, 2241 Avionics Circle, Wright-Patterson AFB, Ohio 45433 (United States); Heller, Eric R. [Air Force Research Laboratory Materials and Manufacturing Directorate, 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433 (United States); Yao, Yu-Feng; Yang, C. C., E-mail: ccycc@ntu.edu.tw [Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan (China)

    2015-04-13

    Highly Ga-doped ZnO (GZO) films of thicknesses d = 5, 25, 50, and 300 nm, grown on 160-nm ZnO buffer layers by molecular beam epitaxy, had 294-K Hall-effect mobilities μ{sub H} of 64.1, 43.4, 37.0, and 34.2 cm{sup 2}/V-s, respectively. This extremely unusual ordering of μ{sub H} vs d is explained by the existence of a very high-mobility Debye tail in the ZnO, arising from the large Fermi-level mismatch between the GZO and the ZnO. Scattering theory in conjunction with Poisson analysis predicts a Debye-tail mobility of 206 cm{sup 2}/V-s at the interface (z = d), falling to 58 cm{sup 2}/V-s at z = d + 2 nm. Excellent fits to μ{sub H} vs d and sheet concentration n{sub s} vs d are obtained with no adjustable parameters.

  3. Potential therapeutic mechanism of extremely low-frequency high-voltage electric fields in cells.

    Science.gov (United States)

    Kim, Ka-Eun; Park, Soon-Kwon; Nam, Sang-Yun; Han, Tae-Jong; Cho, Il-Young

    2016-05-18

    The aim of this survey was to provide background theory based on previous research to elucidate the potential pathway by which medical devices using extremely low-frequency high-voltage electric fields (ELF-HVEF) exert therapeutic effects on the human body, and to increase understanding of the AC high-voltage electrotherapeutic apparatus for consumers and suppliers of the relevant devices. Our review revealed that an ELF field as weak as 1-10 μ V/m can induce diverse alterations of membrane proteins such as transporters and channel proteins, including changes in Ca + + binding to a specific site of the cell surface, changes in ion (e.g., Ca + + ) influx or efflux, and alterations in the ligand-receptor interaction. These alterations then induce cytoplasmic responses within cells (Ca + + , cAMP, kinases, etc.) that can have impacts on cell growth, differentiation, and other functional properties by promoting the synthesis of macromolecules. Moreover, increased cytoplasmic Ca + + involves calmodulin-dependent signaling and consequent Ca + + /calmodulin-dependent stimulation of nitric oxide synthesis. This event in turn induces the nitric oxide-cGMP-protein kinase G pathway, which may be an essential factor in the observed physiological and therapeutic responses.

  4. User characteristics and effect profile of Butane Hash Oil: An extremely high-potency cannabis concentrate.

    Science.gov (United States)

    Chan, Gary C K; Hall, Wayne; Freeman, Tom P; Ferris, Jason; Kelly, Adrian B; Winstock, Adam

    2017-09-01

    Recent reports suggest an increase in use of extremely potent cannabis concentrates such as Butane Hash Oil (BHO) in some developed countries. The aims of this study were to examine the characteristics of BHO users and the effect profiles of BHO. Anonymous online survey in over 20 countries in 2014 and 2015. Participants aged 18 years or older were recruited through onward promotion and online social networks. The overall sample size was 181,870. In this sample, 46% (N=83,867) reported using some form of cannabis in the past year, and 3% reported BHO use (n=5922). Participants reported their use of 7 types of cannabis in the past 12 months, the source of their cannabis, reasons for use, use of other illegal substances, and lifetime diagnosis for depression, anxiety and psychosis. Participants were asked to rate subjective effects of BHO and high potency herbal cannabis. Participants who reported a lifetime diagnosis of depression (OR=1.15, p=0.003), anxiety (OR=1.72, pcannabis. BHO users also reported stronger negative effects and less positive effects when using BHO than high potency herbal cannabis (pcannabis. Copyright © 2017. Published by Elsevier B.V.

  5. Levitation performance of the magnetized bulk high-T{sub c} superconducting magnet with different trapped fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W. [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China); Wang, J.S., E-mail: tonny@mars.swjtu.edu.c [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China); Liao, X.L.; Zheng, S.J.; Ma, G.T.; Zheng, J. [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China); Wang, S.Y. [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China)

    2011-03-15

    Research highlights: {yields} The different trapped fields bring entirely different levitation performance. {yields} The force relaxation characters is directly bound up with the trapped field. {yields} The higher trapped field not means better levitation performance. {yields} An profitable internal induced current configuration will benefit to suppress flux motion. - Abstract: To a high-T{sub c} superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high-T{sub c} superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets.

  6. The Bi-2212 conductor and magnet program at the National High Magnetic Field Laboratory

    CERN Document Server

    Larbalestier, D; Jiang, J; Kametani, F; LoSchiavo, M; Myers, D; Schwartz, J; Shen, T; Trociewitz, U

    2009-01-01

    The NHMFL has had a long running program to develop Bi2Sr2CaCu2Ox (Bi2212) for high field magnets. The recent development of round wire Bi2212 (RW2212) has strengthened the effort to develop solenoid magnets with fields substantially greater than can be achieved with Nb3Sn. The present paper briefly summarizes some of the results obtained at the NHMFL in the past 12 months. It summarizes the talk given by David Larbalestier at WAMSDO on May 24, 2008. Much of the work is ongoing and will be reported in the normal peer reviewed literature in late 2008.

  7. High gradient magnetic filtration and separation. Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, D.

    1986-12-01

    This paper reviews the developing role of high gradient magnetic filtration (HGMF), and separation (HGMS). If discusses the relative position of this technique within the context of the general field of magnetic separation. Its future potential and the basic theory behind it is also reviewed. The two processes; HGMF and HGMS are well known and well established fuels used frequently in mineral processing, for example iron ore. Using different techniques and machines a whole host of uses is possible and the paper concludes by outlining the theory behind this whole area. 11 refs.

  8. High-frequency electric field amplification in a magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, Aleksandr V [Russian Research Centre ' Kurchatov Institute' , Moscow (Russian Federation)

    2006-11-30

    In the investigation of cyclotron ion heating in systems designed for plasma isotope separation, the high-frequency (HF) electric field amplification effect was found to occur in equilibrium plasma. In the present article this effect is treated as a result of the interaction of the plasma placed in a constant external magnetic field with the HF modes of the vacuum chamber. Consistent elaboration of this approach allowed obtaining a clear interpretation of the HF electric field amplification effect and constructing a simple model of HF field excitation in a plasma column embedded in the external magnetic field. (methodological notes)

  9. Yolk-shelled cathode materials with extremely high electrochemical performances prepared by spray pyrolysis

    Science.gov (United States)

    Choi, Seung Ho; Hong, Young Jun; Kang, Yun Chan

    2013-08-01

    A facile, continuous preparation process of yolk-shell-structured lithium-metal oxide powders without a template for use as cathode materials in lithium ion batteries is introduced for the first time. Single and double-shelled LiNi0.5Mn1.5O4 yolk-shell powders as the first target materials are prepared directly by spray pyrolysis from a spray solution with sucrose, at a short residence time of 4 s. Fast combustion and contraction of a carbon-mixed oxide composite intermediate, formed from a micro-sized droplet inside a hot wall reactor maintained at 700 °C, produces the yolk-shell powders. The yolk-shell structure of the precursor powders directly prepared by spray pyrolysis is well maintained even at a high post-treatment temperature of 750 °C. The yolk-shell LiNi0.5Mn1.5O4 powders delivered a 1000th high discharge capacity of 108 mA h g-1 at 10 C. The discharge capacities are as high as 103, 95, and 91 mA h g-1 at extremely high discharge rates of 100, 200, and 300 C and the corresponding specific energy densities are 420, 370, and 328 W h kg-1. The capacity retention at a constant discharge rate of 200 C is 90% after 500 cycles.A facile, continuous preparation process of yolk-shell-structured lithium-metal oxide powders without a template for use as cathode materials in lithium ion batteries is introduced for the first time. Single and double-shelled LiNi0.5Mn1.5O4 yolk-shell powders as the first target materials are prepared directly by spray pyrolysis from a spray solution with sucrose, at a short residence time of 4 s. Fast combustion and contraction of a carbon-mixed oxide composite intermediate, formed from a micro-sized droplet inside a hot wall reactor maintained at 700 °C, produces the yolk-shell powders. The yolk-shell structure of the precursor powders directly prepared by spray pyrolysis is well maintained even at a high post-treatment temperature of 750 °C. The yolk-shell LiNi0.5Mn1.5O4 powders delivered a 1000th high discharge capacity of 108 m

  10. QCD matter in extreme environments

    CERN Document Server

    Fukushima, Kenji

    2011-01-01

    We review various theoretical approaches to the states of QCD matter out of quarks and gluons in extreme environments such as the high-temperature states at zero and finite baryon density and the dimensionally reduced state under an intense magnetic field. The topics at high temperature include the Polyakov loop and the 't Hooft loop in the perturbative regime, the Polyakov loop behaviour and the phase transition in some of non-perturbative methods; the strong-coupling expansion, the large-Nc limit and the holographic QCD models. These analyses are extended to hot and dense matter with a finite baryon chemical potential. We point out that the difficulty in the finite-density problem has similarity to that under a strong magnetic field. We make a brief summary of results related to the topological contents probed by the magnetic field and the Chiral Magnetic Effect. We also address the close connection to the (1+1) dimensional system.

  11. High speed electric motors based on high performance novel soft magnets

    Science.gov (United States)

    Silveyra, J. M.; Leary, A. M.; DeGeorge, V.; Simizu, S.; McHenry, M. E.

    2014-05-01

    Novel Co-based soft magnetic materials are presented as a potential substitute for electrical steels in high speed motors for current industry applications. The low losses, high permeabilities, and good mechanical strength of these materials enable application in high rotational speed induction machines. Here, we present a finite element analysis of Parallel Path Magnetic Technology rotating motors constructed with both silicon steel and Co-based nanocomposite. The later achieved a 70% size reduction and an 83% reduction on NdFeB magnet volume with respect to a similar Si-steel design.

  12. Plasmoid Instability in High-Lundquist-Number Magnetic Reconnection

    CERN Document Server

    Huang, Yi-Min

    2013-01-01

    Our understanding of magnetic reconnection in resistive magnetohydrodynamics has gone through a fundamental change in recent years. The conventional wisdom is that magnetic reconnection mediated by resistivity is slow in laminar high Lundquist ($S$) plasmas, constrained by the scaling of the reconnection rate predicted by Sweet-Parker theory. However, recent studies have shown that when $S$ exceeds a critical value $\\sim10^{4}$, the Sweet-Parker current sheet is unstable to a super-Alfv\\'enic plasmoid instability, with a linear growth rate that scales as $S^{1/4}$. In the fully developed statistical steady state of two-dimensional resistive magnetohydrodynamic simulations, the normalized average reconnection rate is approximately 0.01, nearly independent of $S$, and the distribution function $f(\\psi)$ of plasmoid magnetic flux $\\psi$ follows a power law $f(\\psi)\\sim\\psi^{-1}$. When Hall effects are included, the plasmoid instability may trigger onset of Hall reconnection even when the conventional criterion f...

  13. Very high coercivity magnetic stripes produced by particle rotation

    Energy Technology Data Exchange (ETDEWEB)

    Naylor, R.B.

    1992-12-01

    This paper describes a current research program at Sandia National Laboratories whereby magnetic stripes are produced through the use of a new particle rotation technology. This new process allows the stripes to be produced in bulk and then held in a latent state so that they may be encoded at a later date. Since particle rotation is less dependent on the type of magnetic particle used, very high coercivity particles could provide a way to increase both magnetic tamper-resistance and accidental erasure protection. This research was initially funded by the Department of Energy, Office of Safeguard and Security as a portion of their Science and Technology Base Development, Advanced Security Concepts program. Current program funding is being provided by Sandia National Laboratories as part of their Laboratory Directed Research and Development program.

  14. High voltage magnetic pulse generation using capacitor discharge technique

    Directory of Open Access Journals (Sweden)

    M. Rezal

    2014-12-01

    Full Text Available A high voltage magnetic pulse is designed by applying an electrical pulse to the coil. Capacitor banks are developed to generate the pulse current. Switching circuit consisting of Double Pole Double Throw (DPDT switches, thyristor, and triggering circuit is developed and tested. The coil current is measured using a Hall-effect current sensor. The magnetic pulse generated is measured and tabulated in a graph. Simulation using Finite Element Method Magnetics (FEMM is done to compare the results obtained between experiment and simulation. Results show that increasing the capacitance of the capacitor bank will increase the output voltage. This technology can be applied to areas such as medical equipment, measurement instrument, and military equipment.

  15. Diffusion bonded matrix of high gradient magnetic filter

    Energy Technology Data Exchange (ETDEWEB)

    Soda, F.; Ishibe, H.; Yukawa, T.

    1985-03-01

    For improving the performance of high gradient magnetic filter (HGMF) used in steel mill process waste water treatment, a new filtering medium of diffusion bonded matrix has been developed. This new matrix has an excellent high filtering efficiency for feebly paramagnetic particles, and also has strong structural stiffness that prevents the matrix from compaction and the flow-out of fine wool fractions, which are serious defects in the conventional stainless wool matrix.

  16. High temperature superconducting axial field magnetic coupler: realization and test

    Science.gov (United States)

    Belguerras, L.; Mezani, S.; Lubin, T.; Lévêque, J.; Rezzoug, A.

    2015-09-01

    Contactless torque transmission through a large airgap is required in some industrial applications in which hermetic isolation is necessary. This torque transmission usually uses magnetic couplers, whose dimension strongly depends on the airgap flux density. The use of high temperature superconducting (HTS) coils to create a strong magnetic field may constitute a solution to reduce the size of the coupler. It is also possible to use this coupler to replace a torque tube in transmitting the torque produced by a HTS motor to its load. This paper presents the detailed construction and tests of an axial field HTS magnetic coupler. Pancake coils have been manufactured from BSCCO tape and used in one rotor of the coupler. The second rotor is mainly composed of NdFeB permanent magnets. Several tests have been carried out showing that the constructed coupler is working properly. A 3D finite element (FE) model of the studied coupler has been developed. Airgap magnetic field and torque measurements have been carried out and compared to the FE results. It has been shown that the measured and the computed quantities are in satisfactory agreement.

  17. Exploring Earth's Magnetism and Northern lights in High School Classroom

    Science.gov (United States)

    Prakash, M.; Peticolas, L.

    2008-05-01

    Present studies are being conducted as a part of the outreach project entitled Geomagnetic Event Observation Network by Students (GEONS) to share excitement of the THEMIS (Time History of Events and Macro scale Interactions during Substorm) mission launched during February, 2007. The goal of this mission is to investigate the causality of events that lead to the explosive release of energy (derived from the Sun) stored in the Earth's magnetic field. The visible manifestation of the energy release is Aurora Borealis observed in the Northern hemisphere of the Earth. Inherent to understanding the root-cause of formation of spectacular aurora is the interaction between the Earth's magnetic field and the solar wind charged particles. To achieve this ambitious objective in a high school classroom, students conducted activities using the magnetic field of bar magnets, electromagnets, electromagnetic induction, and Lenz's Law. Following the fundamental understanding of these concepts, students acquired the necessary vocabulary and explored the various components of the interaction between the Earth's magnetic field and the solar wind charged particles. They were also familiarized with the general format in which THEMIS spacecraft data is displayed. In this presentation, we will address student's misconceptions, their struggle to make connections before they can appreciate "Big Idea" in terms of its components. Discussion will highlight the relationship between student understanding of new ideas and how these ideas connect with their prior knowledge.

  18. Low-cost, low-field dedicated extremity magnetic resonance imaging in early rheumatoid arthritis: a 1-year follow-up study

    DEFF Research Database (Denmark)

    Lindegaard, H.M.; Vallø, J.; Hørslev-Petersen, K.;

    2006-01-01

    OBJECTIVE: To study the ability of low-cost low-field dedicated extremity magnetic resonance imaging (E-MRI) to assess and predict erosive joint damage in the wrist and metacarpophalangeal (MCP) joints of patients with early rheumatoid arthritis. METHODS: 24 previously untreated patients with rhe......OBJECTIVE: To study the ability of low-cost low-field dedicated extremity magnetic resonance imaging (E-MRI) to assess and predict erosive joint damage in the wrist and metacarpophalangeal (MCP) joints of patients with early rheumatoid arthritis. METHODS: 24 previously untreated patients...... with rheumatoid arthritis with joint symptoms for treatment with conventional clinical or biochemical examinations, x rays of both hands and wrists, and E-MRI of the dominant wrist and MCP joints. RESULTS: At baseline, all...... patients showed magnetic resonance imaging (MRI) synovitis, and MRI erosions were detected in 21 bones (10 patients). 6 (29%) of these, distributed among two patients, were seen on x ray. One x ray erosion was not detected by MRI. At 1 year, MRI and x ray detected 15 and 8 new erosions, respectively...

  19. Synchrotron Radiation and High Pressure: New Light on Materials Under Extreme Conditions

    Science.gov (United States)

    Hemley, Russell

    2005-03-01

    Current technological advances now make it possible to perform experiments on materials subjected to static or sustained conditions up to multimegabar pressures (>300 GPa) and from cryogenic temperatures to several thousand degrees (˜0.5 eV range). With these techniques, densities of condensed matter can be increased over an order of magnitude, causing numerous transformations and new physical and chemical phenomena to occur. Growth in this area largely been made possible by accelerating developments in diamond-anvil cell methods coupled with new synchrotron radiation techniques. Significant advances have occurred in x-ray diffraction, spectroscopy, inelastic scattering, radiography, and infrared spectroscopy. With recent developments, structure refinements based on polycrystalline data up to multimegabar pressures have been possible. Single-crystal methods have been extended to megabar pressure, with the prospect of full crystallographic refinements. `Three- dimensional' diffraction data can be collected for determining strength, deformation, and elastic tensors at high P-T conditions. Studies carried out during the past three years provide numerous breakthroughs in high-pressure x-ray spectroscopy and a broad range of inelastic scattering methods. Other experiments have exploited the use of x-ray radiography over a range of pressures. Finally, synchrotron infrared measurements have revealed a wealth of high-pressure phenomena, particularly for molecular systems. Examples to be discussed include investigations of dense hydrogen; transformations in molecular materials; novel ceramics; new types of superconductors, electronic, and magnetic materials; and liquids and amorphous materials.

  20. Perpendicular patterned media for high density magnetic storage

    Science.gov (United States)

    Wong, Joyce Y.

    2000-11-01

    Current longitudinal thin-film media in magnetic hard- disk drives are facing an oncoming limit caused by the superparamagnetic effect, in which the individual grains in the medium become so small that they are no longer stable against thermal fluctuation. This situation is undesirable as the stored information may be lost within an unexpectedly short time frame. There have been several proposed solutions in addressing the superparamagnetic limit, and one of them is perpendicular patterned media. In this approach, a periodic array of magnetic pillars is defined lithographically on a non-magnetic substrate. Binary data of ``1'' or ``0'' can be stored in each of these elements, which have two possible magnetization directions perpendicular to the plane of the medium. In our perpendicular patterned media design, Ni columns of 150-230nm diameter with a 6:1 aspect ratio are embedded in an (AlGa)2O 3/GaAs substrate. The fabrication procedure uses a combination of high resolution electron beam lithography, dry etching, and electroplating. The high aspect ratio in the column is achieved by taking advantage of the high etching rate and selectivity of AlGaAs/GaAs over (AlGa)2O 3 in the Cl2 chemically assisted ion beam etching process. In addition to being a robust etching mask, the (AlGa)2O3 layer also plays an important role in the chemical mechanical polishing procedure to remove the overplated Ni mushrooms. Once the Ni columns are fabricated, magnetic characterization is performed using magnetic force microscopy and scanning magnetoresistance microscopy. The former measurement confirms that the electroplated Ni columns are magnetic while the latter determines whether the individual columns are stable enough to retain the recorded information. We have successfully demonstrated recording in our 170nm diameter Ni column array arranged in a square format using a commercial read/write head. This is the first demonstration of single magnetic column per bit data storage in a