WorldWideScience

Sample records for macroscopic magnetization measurements

  1. Macroscopic Quantum Coherence in Antiferromagnetic Molecular Magnets

    Institute of Scientific and Technical Information of China (English)

    HU Hui; LO Rong; ZHU Jia-Lin; XIONG Jia-Jiong

    2001-01-01

    The macroscopic quantum coherence in a biaxial antiferromagnetic molecular magnet in the presence of magnetic field acting parallel to its hard anisotropy axis is studied within the two-sublattice model. On the basis of instanton technique in the spin-coherent-state path-integral representation, both the rigorous Wentzel-Kramers-Brillouin exponent and pre-exponential factor for the ground-state tunnel splitting are obtained. We find that the quantum fluctuations around the classical paths can not only induce a new quantum phase previously reported by Chiolero and Loss (Phys. Rev. Lett. 80 (1998) 169), but also have great influence on the intensity of the ground-state tunnel splitting. Those features clearly have no analogue in the ferromagnetic molecular magnets. We suggest that they may be the universal behaviors in all antiferromagnetic molecular magnets. The analytical results are complemented by exact diagonalization calculation.

  2. Macroscopic Quantum Coherence in Antiferromagnetic Molecular Magnets

    Institute of Scientific and Technical Information of China (English)

    HUHui; LURong; 等

    2001-01-01

    The macroscopic quantum coherence in a biaxial antiferromagnetic molecular magnet in the presence of magnetic field acting parallel to its hard anisotropy axis is studied within the two-sublattice model.On the basis of instanton technique in the spin-coherent-state path-integral representation,both the rigorous Wentzel-Kramers-Brillouin exponent and pre-exponential factor for the ground-state tunnel splitting are obtained.We find that the quantum fluctuations around the classical paths can not only induce a new quantum phase previously reported by Chiolero and Loss (Phys.Rev.Lett.80(1998)169),but also have great influence on the intensity of the ground-state tunnel splitting.Those features clearly have no analogue in the ferromagnetic molecular magnets.We suggest that they may be the universal behaviors in all antiferromagnetic molecular magnets.The analytical results are complemented by exact diagonalization calculation.

  3. Macroscopic Simulation of Isotropic Permanent Magnets

    CERN Document Server

    Bruckner, Florian; Vogler, Christoph; Heinrichs, Frank; Satz, Armin; Ausserlechner, Udo; Binder, Gernot; Koeck, Helmut; Suess, Dieter

    2015-01-01

    Accurate simulations of isotropic permanent magnets require to take the magnetization process into account and consider the anisotropic, nonlinear, and hysteretic material behaviour near the saturation configuration. An efficient method for the solution of the magnetostatic Maxwell equations including the description of isotropic permanent magnets is presented. The algorithm can easily be implemented on top of existing finite element methods and does not require a full characterization of the hysteresis of the magnetic material. Strayfield measurements of an isotropic permanent magnet and simulation results are in good agreement and highlight the importance of a proper description of the isotropic material.

  4. Macroscopic simulation of isotropic permanent magnets

    Science.gov (United States)

    Bruckner, Florian; Abert, Claas; Vogler, Christoph; Heinrichs, Frank; Satz, Armin; Ausserlechner, Udo; Binder, Gernot; Koeck, Helmut; Suess, Dieter

    2016-03-01

    Accurate simulations of isotropic permanent magnets require to take the magnetization process into account and consider the anisotropic, nonlinear, and hysteretic material behaviour near the saturation configuration. An efficient method for the solution of the magnetostatic Maxwell equations including the description of isotropic permanent magnets is presented. The algorithm can easily be implemented on top of existing finite element methods and does not require a full characterization of the hysteresis of the magnetic material. Strayfield measurements of an isotropic permanent magnet and simulation results are in good agreement and highlight the importance of a proper description of the isotropic material.

  5. Macroscopic Simulation of Isotropic Permanent Magnets

    OpenAIRE

    Bruckner, Florian; Abert, Claas; Vogler, Christoph; Heinrichs, Frank; Satz, Armin; Ausserlechner, Udo; Binder, Gernot; Koeck, Helmut; Suess, Dieter

    2015-01-01

    Accurate simulations of isotropic permanent magnets require to take the magnetization process into account and consider the anisotropic, nonlinear, and hysteretic material behaviour near the saturation configuration. An efficient method for the solution of the magnetostatic Maxwell equations including the description of isotropic permanent magnets is presented. The algorithm can easily be implemented on top of existing finite element methods and does not require a full characterization of the...

  6. Macroscopic Quantum Coherence in Magnetic Molecular Clusters

    Institute of Scientific and Technical Information of China (English)

    JIN Yan-Hong; NIE Yi-Hang; LIANG Jiu-Qing; PU Fu-Cho

    2001-01-01

    The oscillation of tunnel splitting in Fes molecular clusters is obtained as a function of magnetic field applied along the hard axis by means of the instanton method with both semiclassical treatment and the effective potential field description of the quantum spin system. The theoretical splittings of the instanton method are compared with the numerical result by diagonalization of spin Hamiltonian operators and experimental observations. By taking the appropriate parameters, our theoretical formula yields a result the same as the experimental observation.

  7. Self-Feeding Turbulent Magnetic Reconnection on Macroscopic Scales

    CERN Document Server

    Lapenta, Giovanni

    2008-01-01

    Within a MHD approach we find magnetic reconnection to progress in two entirely different ways. The first is well-known: the laminar Sweet-Parker process. But a second, completely different and chaotic reconnection process is possible. This regime has properties of immediate practical relevance: i) it is much faster, developing on scales of the order of the Alfv\\'en time, and ii) the areas of reconnection become distributed chaotically over a macroscopic region. The onset of the faster process is the formation of closed circulation patterns where the jets going out of the reconnection regions turn around and forces their way back in, carrying along copious amounts of magnetic flux.

  8. Witnessing Macroscopic Entanglement in a Staggered Magnetic Field

    CERN Document Server

    Hide, J; Son, W; Vedral, V; Hide, Jenny; Lawrie, Ian; Son, Wonmin; Vedral, Vlatko

    2007-01-01

    We investigate macroscopic entanglement in an infinite XX spin-1/2 chain with staggered magnetic field, $B_l=B+e^{-i\\pi l}b$. Using single-site entropy and by constructing an entanglement witness, we search for the existence of entanglement when the system is at absolute zero, as well as in thermal equilibrium. Although the role of the alternating magnetic field $b$ is, in general, to suppress entanglement as do $B$ and $T$, we find that when T=0, introducing $b$ allows the existence of entanglement even when the uniform magnetic field $B$ is arbitrarily large. We find that the region and the amount of entanglement in the spin chain can be enhanced by a staggered magnetic field.

  9. New Tests of Macroscopic Local Realism using Continuous Variable Measurements

    CERN Document Server

    Reid, M D

    2001-01-01

    We show that quantum mechanics predicts an Einstein-Podolsky-Rosen paradox (EPR), and also a contradiction with local hidden variable theories, for photon number measurements which have limited resolving power, to the point of imposing an uncertainty in the photon number result which is macroscopic in absolute terms. We show how this can be interpreted as a failure of a new, very strong premise, called macroscopic local realism. We link this premise to the Schrodinger-cat paradox. Our proposed experiments ensure all fields incident on each measurement apparatus are macroscopic. We show that an alternative measurement scheme corresponds to balanced homodyne detection of quadrature phase amplitudes. The implication is that where either EPR correlations or failure of local realism is predicted for continuous variable (quadrature phase amplitude) measurements, one can perform a modified experiment which would lead to conclusions about the much stronger premise of macroscopic local realism.

  10. Nuclear magnetic resonance studies of macroscopic morphology and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Barrall, Geoffrey Alden [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1995-09-01

    Nuclear magnetic resonance techniques are traditionally used to study molecular level structure and dynamics with a noted exception in medically applied NMR imaging (MRI). In this work, new experimental methods and theory are presented relevant to the study of macroscopic morphology and dynamics using NMR field gradient techniques and solid state two-dimensional exchange NMR. The goal in this work is not to take some particular system and study it in great detail, rather it is to show the utility of a number of new and novel techniques using ideal systems primarily as a proof of principle. By taking advantage of the analogy between NMR imaging and diffraction, one may simplify the experiments necessary for characterizing the statistical properties of the sample morphology. For a sample composed of many small features, e.g. a porous medium, the NMR diffraction techniques take advantage of both the narrow spatial range and spatial isotropy of the sample`s density autocorrelation function to obtain high resolution structural information in considerably less time than that required by conventional NMR imaging approaches. The time savings of the technique indicates that NMR diffraction is capable of finer spatial resolution than conventional NMR imaging techniques. Radio frequency NMR imaging with a coaxial resonator represents the first use of cylindrically symmetric field gradients in imaging. The apparatus as built has achieved resolution at the micron level for water samples, and has the potential to be very useful in the imaging of circularly symmetric systems. The study of displacement probability densities in flow through a random porous medium has revealed the presence of features related to the interconnectedness of the void volumes. The pulsed gradient techniques used have proven successful at measuring flow properties for time and length scales considerably shorter than those studied by more conventional techniques.

  11. Self-feeding turbulent magnetic reconnection on macroscopic scales.

    Science.gov (United States)

    Lapenta, Giovanni

    2008-06-13

    Within a MHD approach we find magnetic reconnection to progress in two entirely different ways. The first is well known: the laminar Sweet-Parker process. But a second, completely different and chaotic reconnection process is possible. This regime has properties of immediate practical relevance: (i) it is much faster, developing on scales of the order of the Alfvén time, and (ii) the areas of reconnection become distributed chaotically over a macroscopic region. The onset of the faster process is the formation of closed-circulation patterns where the jets going out of the reconnection regions turn around and force their way back in, carrying along copious amounts of magnetic flux.

  12. Macroscopic behavior and microscopic magnetic properties of nanocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Lähderanta, E., E-mail: Erkki.Lahderanta@lut.fi [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Ryzhov, V.A. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Petersburg Nuclear Physics Institute, NRC “Kurchatov Institute”, Orlova Coppice, Gatchina, Leningrad province 188300 (Russian Federation); Lashkul, A.V. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Galimov, D.M. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); South Ural State University, 454080 Chelyabinsk (Russian Federation); Titkov, A.N. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); A. F. Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation); Matveev, V.V. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Saint-Petersburg State University, Saint-Petersburg 198504 (Russian Federation); Mokeev, M.V. [Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg (Russian Federation); Kurbakov, A.I. [Petersburg Nuclear Physics Institute, NRC “Kurchatov Institute”, Orlova Coppice, Gatchina, Leningrad province 188300 (Russian Federation); Lisunov, K.G. [Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Institute of Applied Physics ASM, Academiei Str., 5, MD 2028 Kishinev (Moldova, Republic of)

    2015-06-01

    Here are presented investigations of powder and glass-like samples containing carbon nanoparticles, not intentionally doped and doped with Ag, Au and Co. The neutron diffraction study reveals an amorphous structure of the samples doped with Au and Co, as well as the magnetic scattering due to a long-range FM order in the Co-doped sample. The composition and molecular structure of the sample doped with Au is clarified with the NMR investigations. The temperature dependence of the magnetization, M (T), exhibits large irreversibility in low fields of B=1–7 mT. M (B) saturates already above 2 T at high temperatures, but deviates from the saturation behavior below ~50 (150 K). Magnetic hysteresis is observed already at 300 K and exhibits a power-law temperature decay of the coercive field, B{sub c} (T). The macroscopic behavior above is typical of an assembly of partially blocked magnetic nanoparticles. The values of the saturation magnetization, M{sub s}, and the blocking temperature, T{sub b}, are obtained as well. However, the hysteresis loop in the Co-doped sample differs from that in other samples, and the values of B{sub c} and M{sub s} are noticeably increased. - Highlights: • We have investigated powder and glassy samples with carbon nanoparticles. • They include an undoped sample and those doped with Ag, Au and Co. • Neutron diffraction study reveals amorphous structure of Au- and Co-doped samples. • Composition and molecular structure of Au-doped sample was investigated with NMR. • Magnetic behavior is typical of an assembly of partially blocked magnetic nanoparticles.

  13. Measurement-Induced Macroscopic Superposition States in Cavity Optomechanics

    Science.gov (United States)

    Hoff, Ulrich B.; Kollath-Bönig, Johann; Neergaard-Nielsen, Jonas S.; Andersen, Ulrik L.

    2016-09-01

    A novel protocol for generating quantum superpositions of macroscopically distinct states of a bulk mechanical oscillator is proposed, compatible with existing optomechanical devices operating in the bad-cavity limit. By combining a pulsed optomechanical quantum nondemolition (QND) interaction with nonclassical optical resources and measurement-induced feedback, the need for strong single-photon coupling is avoided. We outline a three-pulse sequence of QND interactions encompassing squeezing-enhanced cooling by measurement, state preparation, and tomography.

  14. Magnetic studies of colossal magnetoresistance perovskites on macroscopic, mesoscopic and microscopic length scales

    Indian Academy of Sciences (India)

    S M Yusuf

    2004-07-01

    We have investigated magnetic correlations in various CMR manganites on macroscopic, mesoscopic and microscopic length scales by carrying out DC magnetization, neutron depolarization, and neutron diffraction measurements. We present here the effect of substituting Mn with Fe and La with Dy in the ferromagnetic La0.7- CaMnO3 ( ∼ 0.3 - 0.33) compounds. Neutron diffraction has been used in order to characterize the long-range magnetic order and its gradual suppression by the substitution. Neutron depolarization study has been carried out in order to bridge the gap in our understanding regarding the nature of magnetic correlation obtained from the macroscopic and microscopic measurements. In particular, our study on La0.67Ca0.33Mn0.9Fe0.1O3 has established the fact that a true double exchange mediated spin-glass is insulating. In another study of La-site ionic size effect and its disorder in (La1-Dy)0.7Ca0.3MnO3, we have investigated the evolution of the length scale of magnetic ordering with a possible microscopic explanation and the results have been compared with that for the light rare earth substituted compounds.

  15. Indirect measurement of interfacial melting from macroscopic ice observations.

    Science.gov (United States)

    Saruya, Tomotaka; Kurita, Kei; Rempel, Alan W

    2014-06-01

    Premelted water that is adsorbed to particle surfaces and confined to capillary regions remains in the liquid state well below the bulk melting temperature and can supply the segregated growth of ice lenses. Using macroscopic measurements of ice-lens initiation position in step-freezing experiments, we infer how the nanometer-scale thicknesses of premelted films depend on temperature depression below bulk melting. The interfacial interactions between ice, liquid, and soda-lime glass particles exhibit a power-law behavior that suggests premelting in our system is dominated by short-range electrostatic forces. Using our inferred film thicknesses as inputs to a simple force-balance model with no adjustable parameters, we obtain good quantitative agreement between numerical predictions and observed ice-lens thickness. Macroscopic observations of lensing behavior have the potential as probes of premelting behavior in other systems.

  16. Measurement-induced macroscopic superposition states in cavity optomechanics

    CERN Document Server

    Hoff, Ulrich B; Neergaard-Nielsen, Jonas S; Andersen, Ulrik L

    2016-01-01

    We present a novel proposal for generating quantum superpositions of macroscopically distinct states of a bulk mechanical oscillator, compatible with existing optomechanical devices operating in the readily achievable bad-cavity limit. The scheme is based on a pulsed cavity optomechanical quantum non-demolition (QND) interaction, driven by displaced non-Gaussian states, and measurement-induced feedback, avoiding the need for strong single-photon optomechanical coupling. Furthermore, we show that single-quadrature cooling of the mechanical oscillator is sufficient for efficient state preparation, and we outline a three-pulse protocol comprising a sequence of QND interactions for squeezing-enhanced cooling, state preparation, and tomography.

  17. Macroscopic motion of sheath-connected blobs in magnetic fields with arbitrary topology

    Science.gov (United States)

    Stepanenko, A. A.; Lee, W.; Krasheninnikov, S. I.

    2017-01-01

    In this study, macroscopic motion of sheath-connected blobs in magnetic fields, having arbitrary topology of the field lines and unfrozen in plasma, is analyzed within the electrostatic limit. Two distinct cases of magnetic configurations, with small and large curvature of the field lines, are considered and the criterion to discern them is deduced. For magnetic configurations with small curvature of the field lines, it is demonstrated that asymmetry of plasma distribution at the blob ends can drive macroscopic motion of a filament due to formation of unequal sheath potentials and establishing the effective Boltzmann potential. For a specific case of magnetic fields with small curvature of the field lines and identical metrics at the sheaths, we show that macroscopic motion of a plasma filament is determined by an effective electrostatic potential, which remains constant in time. For magnetic configurations with large curvature of the field lines, it is shown that motion of sufficiently large blobs is governed by integral distribution of plasma and magnetic field parameters along the field lines leading to blob adjusting its shape and position to the lead of the magnetic field lines in the course of its motion, whereas propagation of small and medium sized blobs can be represented as mutually independent motion of filament transverse cross-sections across the magnetic field lines. The qualitative conclusions on regularities of filament motion are supplied with numerical simulations of blob dynamics in two cases of tokamak-like magnetic fields with sheared and non-sheared field lines.

  18. Macroscopic Quantum Phenomena and Topological Phase Interference Effects in Single-Domain Magnets

    Institute of Scientific and Technical Information of China (English)

    L(U) Rong; ZHU Jialin

    2001-01-01

    The tunneling of macroscopic object is one of the most fascinating phenomena in condensed matter physics.During the last decade,the problem of quantum tunneling of magnetization in nanometer-scale magnets has attracted a great deal of theoretical and experimental interest.A review of recent theoretical research of the macroscopic quantum phenomena in nanometer-scale single-domain magnets is presented in this paper.It includes macroscopic quantum tunneling (MQT) and coherence (MQC) in single-domain magnetic particles,the topological phase interference or spin-parity effects,and tunneling of magnetization in an arbitrarily directed magnetic field.The general formulas are shown to evaluate the tunneling rate and the tunneling level splitting for single-domain AFM particles.A nontrivial generalization of Kramers degeneracy for double-well system is provided to coherently spin tunneling for spin systems with m-fold rotational symmetry.The effects induced by the external magnetic field have been studied,where the field is along the easy,medium,hard axis,or arbitrary direction.

  19. A macroscopic description of coherent geo-magnetic radiation from cosmic-ray air showers

    NARCIS (Netherlands)

    Scholten, O.; Werner, K.; Rusydi, F.

    2008-01-01

    We have developed a macroscopic description of coherent electromagnetic radiation from air showers initiated by ultra-high-energy cosmic rays due to the presence of the geo-magnetic field. This description offers it simple and direct insight in the relation between the properties of the air shower a

  20. Quantification of synovistis by MRI: correlation between dynamic and static gadolinium-enhanced magnetic resonance imaging and microscopic and macroscopic signs of synovial inflammation

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Stoltenberg, M; Løvgreen-Nielsen, P;

    1998-01-01

    Dynamic and static gadolinium-diethylenetriaminepentaacetic acid(Gd-DTPA)-enhanced magnetic resonance imaging (MRI) were evaluated as measures of joint inflammation in arthritis, by a comparison with macroscopic and microscopic signs of synovitis. Furthermore, the importance of the size of the ev......Dynamic and static gadolinium-diethylenetriaminepentaacetic acid(Gd-DTPA)-enhanced magnetic resonance imaging (MRI) were evaluated as measures of joint inflammation in arthritis, by a comparison with macroscopic and microscopic signs of synovitis. Furthermore, the importance of the size...

  1. Quantum dynamics of a macroscopic magnet operating as an environment of a mechanical oscillator

    Science.gov (United States)

    Foti, C.; Cuccoli, A.; Verrucchi, P.

    2016-12-01

    We study the dynamics of a bipartite quantum system in a way such that its formal description keeps holding even if one of its parts becomes macroscopic; the problem is related to the analysis of the quantum-to-classical crossover, but our approach implies that the whole system stays genuinely quantum. The aim of the work is to understand (1) if, (2) to what extent, and possibly (3) how the evolution of a macroscopic environment testifies to the coupling with its microscopic quantum companion. To this purpose we consider a magnetic environment made of a large number of spin-1/2 particles, coupled with a quantum mechanical oscillator, possibly in the presence of an external magnetic field. We take the value of the total environmental spin S constant and large, which allows us to consider the environment as one single macroscopic system, and further deal with the hurdles of the spin-algebra via approximations that are valid in the large-S limit. We find an insightful expression for the propagator of the whole system, where we identify an effective "back-action" term, i.e., an operator acting on the magnetic environment only, and yet missing in the absence of the quantum principal system. This operator emerges as a time-dependent magnetic anisotropy whose character, whether uniaxial or planar, also depends on the detuning between the frequency of the oscillator and the level splitting in the spectrum of the free magnetic system, induced by the possible presence of the external field. The time dependence of the anisotropy is analyzed, and its effects on the dynamics of the magnet, as well as its relation to the entangling evolution of the overall system, are discussed.

  2. Macroscopic characterization of cell electroporation in biological tissue based on electrical measurements

    Science.gov (United States)

    Cima, Lionel F.; Mir, Lluis M.

    2004-11-01

    A method is described to experimentally determine the temporal evolution of state variables involved in the electroporation of biological tissue, i.e., the transmembrane voltage and the macroscopic current flowing in the electropores. Indeed, the electrical parameters of the extracellular, intracellular, and unaltered membrane contributions as well as the electropores electrical characteristics can be deduced from the measurement of the tissue bioimpedance and from the variations of both the macroscopic voltage applied to the tissue and the delivered current.

  3. Dynamic Chiral Magnetic Effect and Faraday Rotation in Macroscopically Disordered Helical Metals

    Science.gov (United States)

    Ma, J.; Pesin, D. A.

    2017-03-01

    We develop an effective medium theory for electromagnetic wave propagation through gapless nonuniform systems with a dynamic chiral magnetic effect. The theory allows us to calculate macroscopic-disorder-induced corrections to the values of optical, as well as chiral magnetic conductivities. In particular, we show that spatial fluctuations of the optical conductivity induce corrections to the effective value of the chiral magnetic conductivity. The absolute value of the effect varies strongly depending on the system parameters, but yields the leading frequency dependence of the polarization rotation and circular dichroism signals. Experimentally, these corrections can be observed as features in the Faraday rotation angle near frequencies that correspond to the bulk plasmon resonances of a material. Such features are not expected to be present in single-crystal samples.

  4. Studies of Dynamic, Radiative Macroscopic Magnetized HED Plasmas with Closed B-Field Lines

    Energy Technology Data Exchange (ETDEWEB)

    Frese, Michael H. [NumerEx, LLC, Albuquerque, NM (United States); Frese, Sherry D. [NumerEx, LLC, Albuquerque, NM (United States)

    2013-11-01

    The purpose of this research has been to study the physics of macroscopic magnetized high-energy-density laboratory plasmas (HEDLPs) created through the compression of a high-beta compact toroid (CT) plasma having closed magnetic field lines. The high-beta CT chosen for this work is a field-reversed configuration (FRC). The basic approach is to investigate CT plasmas as they are compressed to a HED state by the electromagnetic implosion of a surrounding metallic shell or solid liner (Figure 1). The shell provides an axisymmetric, electrically-conducting boundary around the plasma and its supporting magnetic field and is imploded by means of the magnetic pressure force arising from axial current flow in the liner interacting with its associated azimuthal magnetic field. Compression of the CT will bring the plasma to fusion temperatures at higher densities and magnetic fields (multi-MegaGauss [MG]) than have previously been present in conventional magnetic fusion approaches. The resulting energy densities will be ~1 Mbar or greater and thus will place the plasma in a parameter space intermediate to MFE and IFE. This work has been a collaboration between the Air Force Research Laboratory, Los Alamos National Laboratory, and NumerEx, LLC.

  5. The association between histological, macroscopic and magnetic resonance imaging assessed synovitis in end-stage knee osteoarthritis

    DEFF Research Database (Denmark)

    Riis, Robert Gabriel Coumine; Gudbergsen, Henrik; Simonsen, Ole

    2017-01-01

    OBJECTIVES: To investigate the association between magnetic resonance imaging (MRI), macroscopic and histological assessments of synovitis in end-stage knee osteoarthritis (KOA). METHODS: Synovitis of end-stage osteoarthritic knees was assessed using non-contrast-enhanced (CE), contrast-enhanced ......OBJECTIVES: To investigate the association between magnetic resonance imaging (MRI), macroscopic and histological assessments of synovitis in end-stage knee osteoarthritis (KOA). METHODS: Synovitis of end-stage osteoarthritic knees was assessed using non-contrast-enhanced (CE), contrast......-enhanced magnetic resonance imaging (CE-MRI) and dynamic contrast-enhanced (DCE)-MRI prior to (TKR) and correlated with microscopic and macroscopic assessments of synovitis obtained intraoperatively. Multiple bivariate correlations were used with a pre-specified threshold of 0.70 for significance. Also, multiple...

  6. Strain-induced macroscopic magnetic anisotropy from smectic liquid-crystalline elastomer-maghemite nanoparticle hybrid nanocomposites.

    Science.gov (United States)

    Haberl, Johannes M; Sánchez-Ferrer, Antoni; Mihut, Adriana M; Dietsch, Hervé; Hirt, Ann M; Mezzenga, Raffaele

    2013-06-21

    We combine tensile strength analysis and X-ray scattering experiments to establish a detailed understanding of the microstructural coupling between liquid-crystalline elastomer (LCE) networks and embedded magnetic core-shell ellipsoidal nanoparticles (NPs). We study the structural and magnetic re-organization at different deformations and NP loadings, and the associated shape and magnetic memory features. In the quantitative analysis of a stretching process, the effect of the incorporated NPs on the smectic LCE is found to be prominent during the reorientation of the smectic domains and the softening of the nanocomposite. Under deformation, the soft response of the nanocomposite material allows the organization of the nanoparticles to yield a permanent macroscopically anisotropic magnetic material. Independent of the particle loading, the shape-memory properties and the smectic phase of the LCEs are preserved. Detailed studies on the magnetic properties demonstrate that the collective ensemble of individual particles is responsible for the macroscopic magnetic features of the nanocomposite.

  7. Materials with low DC magnetic susceptibility for sensitive magnetic measurements

    CERN Document Server

    Khatiwada, Rakshya; Kendrick, Rachel; Khosravi, Marjan; Peters, Michael; Smith, Erick; Snow, Mike

    2015-01-01

    Materials with very low DC magnetic susceptibility have many scientific applications. To our knowledge however, relatively little research has been conducted with the goal to produce a totally nonmagnetic material. This phrase in our case means after spatially averaging over macroscopic volumes, it possesses an average zero DC magnetic susceptibility. We report measurements of the DC magnetic susceptibility of three different types of nonmagnetic materials at room temperature: (I) solutions of paramagnetic salts and diamagnetic liquids, (II) liquid gallium-indium alloys and (III) pressed powder mixtures of tungsten and bismuth. The lowest measured magnetic susceptibility among these candidate materials is in the order of 10^-9 cgs volume susceptibility units, about two orders of magnitude smaller than distilled water. In all cases, the measured concentration dependence of the magnetic susceptibility is consistent with that expected for the weighted sum of the susceptibilities of the separate components within...

  8. Enhancement of magnetic coercivity and macroscopic quantum tunneling in monodispersed Co/CoO cluster assemblies

    OpenAIRE

    Peng, D. L.; Sumiyama, Kenji; Hihara, Takehiko; Yamamuro, S.; ヒハラ, タケヒコ; スミヤマ, ケンジ; 日原, 岳彦; 隅山, 兼治; Hihara, T.; Sumiyama, K.

    1999-01-01

    Magnetic properties have been measured for monodisperse-sized Co/CoO cluster assemblies prepared by a plasma-gas-condensation-type cluster beam deposition technique. The clear correlation obtained between exchange bias field and coercivity suggests the enhancement of uniaxial anisotropy owing to the exchange coupling between the ferromagnetic Co core and antiferromagnetic CoO shell, and magnetic disorder at the core-shell interface. A nonthermal magnetic relaxation observed below 8 K, being r...

  9. Basic Characteristics of a Macroscopic Measure for Detecting Abnormal Changes in a Multiagent System

    Directory of Open Access Journals (Sweden)

    Tetsuo Kinoshita

    2015-04-01

    Full Text Available Multiagent application systems must deal with various changes in both the system and the system environment at runtime. Generally, such changes have undesirable negative effects on the system. To manage and control the system, it is important to observe and detect negative effects using an appropriate observation function of the system’s behavior. This paper focuses on the design of this function and proposes a new macroscopic measure with which to observe behavioral characteristics of a runtime multiagent system. The proposed measure is designed as the variance of fluctuation of a macroscopic activity factor of the whole system, based on theoretical analysis of the macroscopic behavioral model of a multiagent system. Experiments are conducted to investigate basic characteristics of the proposed measure, using a test bed system. The results of experiments show that the proposed measure reacts quickly and increases drastically in response to abnormal changes in the system. Hence, the proposed measure is considered a measure that can be used to detect undesirable changes in a multiagent system.

  10. Basic Characteristics of a Macroscopic Measure for Detecting Abnormal Changes in a Multiagent System

    Science.gov (United States)

    Kinoshita, Tetsuo

    2015-01-01

    Multiagent application systems must deal with various changes in both the system and the system environment at runtime. Generally, such changes have undesirable negative effects on the system. To manage and control the system, it is important to observe and detect negative effects using an appropriate observation function of the system’s behavior. This paper focuses on the design of this function and proposes a new macroscopic measure with which to observe behavioral characteristics of a runtime multiagent system. The proposed measure is designed as the variance of fluctuation of a macroscopic activity factor of the whole system, based on theoretical analysis of the macroscopic behavioral model of a multiagent system. Experiments are conducted to investigate basic characteristics of the proposed measure, using a test bed system. The results of experiments show that the proposed measure reacts quickly and increases drastically in response to abnormal changes in the system. Hence, the proposed measure is considered a measure that can be used to detect undesirable changes in a multiagent system. PMID:25897499

  11. Measurements of effective total macroscopic cross sections and effective energy of continuum beam

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Hisao [Rikkyo Univ., Yokosuka, Kanagawa (Japan). Inst. for Atomic Energy

    1998-03-01

    Two practically useful quantities are introduced in this study to characterize a continuum neutron beam and to describe transmission phenomena of the beam in field of quantitative neutron radiography: an effective energy instead of a peak energy or a mean energy of the spectrum and an effective total macroscopic (ETM) cross section instead of a total macroscopic (TM) cross section defined at the monochromatic energy. The effective energy was evaluated by means of energy dependence of ETM cross section. To realize the method a beam quality indicator (BQI) has been proposed recently. Several effective energies were measured for non-filtered, filtered neutron beams, and outputs of neutron guide tubes in world by the BQI. A thermal neutron beam and three beams modulated by Pb filters with different thicknesses are studied to measure ETM cross sections for various materials and summarized in a table. Validity of the effective energy determined by the BQI is discussed relating with ETM cross sections of materials. (author)

  12. 3D shape measurement of macroscopic objects in digital off-axis holography using structured illumination.

    Science.gov (United States)

    Grosse, Marcus; Buehl, Johannes; Babovsky, Holger; Kiessling, Armin; Kowarschik, Richard

    2010-04-15

    We propose what we believe to be a novel approach to measure the 3D shape of arbitrary diffuse-reflecting macroscopic objects in holographic setups. Using a standard holographic setup, a second CCD and a liquid-crystal-on-silicon spatial light modulator to modulate the object wave, the method yields a dense 3D point cloud of an object or a scene. The calibration process is presented, and first quantitative results of a shape measurement are shown and discussed. Furthermore, a shape measurement of a complex object is displayed to demonstrate its universal use.

  13. Ghost Cell Suspensions as Blood Analogue Fluid for Macroscopic Particle Image Velocimetry Measurements.

    Science.gov (United States)

    Jansen, Sebastian V; Müller, Indra; Nachtsheim, Max; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2016-02-01

    Spatially resolved measurement of blood flow is of great interest in the development of artificial blood-carrying devices such as blood pumps, heart valve prostheses, and oxygenators. Particle image velocimetry (PIV) is able to measure instantaneous velocity fields in a plane with high accuracy and is being used more frequently for the development of such devices. However, as this measurement technique is based on optical access, blood flow at physiological hematocrit values is difficult to measure due to its low transparency and multiscattering properties. So far, only very small dimensions (in the range of 400 μm) can be measured using PIV. A suspension of ghost cells (GCs) offers a higher optical transparency than blood while having a similar rheological behavior. In this study, a procedure for the production of GC suspensions containing a very low intracellular hemoglobin concentration is presented. With the help of multiple rounds of controlled cell lysis, the intracellular hemoglobin concentration could be decreased to a point where a standard macroscopic PIV measurement was possible. A velocity profile of a 44% GC suspension in a circular channel with a diameter of 9.5 mm was measured with high spatial resolution. Meanwhile, the rheological behavior was found to be comparable with blood.

  14. Pass-through Mach-Zehnder topologies for macroscopic quantum measurements

    CERN Document Server

    Khalili, F Ya

    2011-01-01

    Several relatively small-scale experimental setups aimed on prototyping of future laser gravitational-wave detectors and testing of new methods of quantum measurements with macroscopic mechanical objects, are under development now. In these devices, not devoted directly to the gravitational-wave detection, Mach-Zehnder interferometer with pass-through Fabry-Perot cavities in the arms can be used instead of the standard Michelson/Fabry-Perot one. The advantage of this topology is that it does not contain high-reflectivity end mirrors with multilayer coatings, which Brownian noise could constitute the major part of the noise budget of the Michelson/Fabry-Perot interferometers. We consider here two variants of this topology: the "ordinary" position meter scheme, and a new variant of the quantum speed meter.

  15. Signatures of granular superconductivity and Josephson effects in macroscopic measurements: the case of new superconductors

    Directory of Open Access Journals (Sweden)

    S Senoussi

    2006-09-01

    Full Text Available   We report systematic investigations of the magnetic superconducting properties of the new superconducting materials (NS: New high temperature superconductors (HTS, Organic superconductors (OS, fullerenes, carbon nanotubes, MgB2 etc. We show that, contrary to conventional superconductors where the superconducting state can be coherent over several tenths of km, the macroscopic coherence range lc of the NS is often as short as 0.1 to 10 µm typically. As a consequence, the magnetic properties are dominated by granular-like effects as well as Josephson coupling between grains. Here, we concentrate on HTS ceramics and organic superconductors exclusively. In the first case we observe three distinct regimes: (i At very low field (H < 5 Oe to say all the grains are coupled via Josephson effect and lc can be considered as infinite. (2 At intermediate field (5 < H < 50 Oe, typically the grains are gradually decoupled by H and/or T. (iii At higher fields all the grains are decoupled and lc roughly coincides with the diameter of the metallurgical grains. The case of OS is more subtle and is connected with a kind of order-disorder transition that occurs in most of them. For instance, in this study, we exploit quenched disorder (after crossing such a transition in the -(BEDT-TTF2Cu[N(CN2]Br layered organic superconductor to get new insights on both the superconducting state (T £ 11.6 K and the glassy transition at Tg, by studying the superconducting properties as functions of annealing time and annealing temperature around the glassy transition. Our main result is that the data can be described by a percolation molecular cluster model in which the topology and the growth of the molecular clusters obey an Ising spin-glass-like model with Tg ≈ 80 K for the hydrogenated compound and Tg ≈ 55 K for the fully deuterated one.

  16. Aharonov-Casher-effect suppression of macroscopic tunneling of magnetic flux.

    Science.gov (United States)

    Friedman, Jonathan R; Averin, D V

    2002-02-04

    We suggest a system in which the amplitude of macroscopic flux tunneling can be modulated via the Aharonov-Casher effect. The system is an rf SQUID with the Josephson junction replaced by a Bloch transistor--two junctions separated by a small superconducting island on which the charge can be induced by an external gate voltage. When the Josephson coupling energies of the junctions are equal and the induced charge is q = e, destructive interference between tunneling paths brings the flux tunneling rate to zero. The device may also be useful as a qubit for quantum computation.

  17. Sub-Kelvin Cooling of a Macroscopic Oscillator and femto-Newton Force Measurement

    CERN Document Server

    Müller, F; Wang, L J

    2007-01-01

    Measuring very small forces, particularly those of a gravitational nature, has always been of great interest, as fundamental tests of our understanding of the physical laws. Ultra-long period mechanical oscillators, typically used in such measurements, will have kT/2 of thermal energy associated with each degree of freedom, owing to the equal-partition of energy. Moreover, additional seismic fluctuations in the low frequency band can raise this equivalent temperature significantly to 10^5 K. Recently, various methods using opto-mechanical forces have been reported to decrease this thermal energy for MHz, micro-cantilever oscillators, effectively cooling them. Here we show the direct, dynamical cooling of a gram-size, macroscopic oscillator to 300 mK in equivalent temperature - noise reduction by a factor of 10^6. By precisely measuring the torsional oscillator's position, we dynamically provide an external 'viscous' damping force. Such an added, dissipative force is essentially free of noise, resulting in rap...

  18. Improving the specificity of R2' to the deoxyhaemoglobin content of brain tissue: Prospective correction of macroscopic magnetic field gradients.

    Science.gov (United States)

    Blockley, Nicholas P; Stone, Alan J

    2016-07-15

    The reversible transverse relaxation rate, R2', is sensitive to the deoxyhaemoglobin content of brain tissue, enabling information about the oxygen extraction fraction to be obtained. However, R2' is also sensitive to macroscopic magnetic field gradients, particularly at air-tissue interfaces where a large susceptibility difference is present. It is important that this latter effect is minimised in order to produce meaningful estimates of blood oxygenation. Therefore, the aim of this study was to implement a technique to prospectively correct for the effect of susceptibility induced magnetic field gradients on R2' weighted data. This was achieved by combining the Gradient-Echo Slice Excitation Profile Imaging (GESEPI) technique with an Asymmetric Spin Echo (ASE) pulse sequence. The main advantages of this approach are (i) shorter acquisition times, since a separately acquired magnetic field map is not required and (ii) simpler analysis, since retrospective correction for the effects of magnetic field gradients in postprocessing is not required. In these experiments we show that with this newly developed technique it is possible to correct the majority of grey matter voxels for the expected distribution of through-slice magnetic field gradients to produce maps of R2' in a short scan duration.

  19. Macroscopic fields in thin ferromagnetic sheets taking into account eddy currents and Landau-Lifshitz magnetization

    Science.gov (United States)

    Dupré, Luc; Olyslager, Frank; Melkebeek, Jan

    2004-05-01

    The paper deals with a numerical model for the evaluation of the electromagnetic behavior in thin magnetic sheets. Therefore, we consider Maxwell's equations together with a nonlinear magnetic constitutive law described by the Landau-Lifshitz equation. We present a suitable numerical approximation based upon a finite element-finite difference method. At each time step in the numerical scheme, the magnetization dynamics is calculated analytically by introducing for each finite element node a transformation towards a local coordinate system.

  20. Particle velocity measurements with macroscopic fluorescence imaging in lymph tissue mimicking microfluidic phantoms

    Science.gov (United States)

    Hennessy, Ricky; Koo, Chiwan; Ton, Phuc; Han, Arum; Righetti, Raffaella; Maitland, Kristen C.

    2011-03-01

    Ultrasound poroelastography can quantify structural and mechanical properties of tissues such as stiffness, compressibility, and fluid flow rate. This novel ultrasound technique is being explored to detect tissue changes associated with lymphatic disease. We have constructed a macroscopic fluorescence imaging system to validate ultrasonic fluid flow measurements and to provide high resolution imaging of microfluidic phantoms. The optical imaging system is composed of a white light source, excitation and emission filters, and a camera with a zoom lens. The field of view can be adjusted from 100 mm x 75 mm to 10 mm x 7.5 mm. The microfluidic device is made of polydimethylsiloxane (PDMS) and has 9 channels, each 40 μm deep with widths ranging from 30 μm to 200 μm. A syringe pump was used to propel water containing 15 μm diameter fluorescent microspheres through the microchannels, with flow rates ranging from 0.5 μl/min to 10 μl/min. Video was captured at a rate of 25 frames/sec. The velocity of the microspheres in the microchannels was calculated using an algorithm that tracked the movement of the fluorescent microspheres. The imaging system was able to measure particle velocities ranging from 0.2 mm/sec to 10 mm/sec. The range of flow velocities of interest in lymph vessels is between 1 mm/sec to 10 mm/sec; therefore our imaging system is sufficient to measure particle velocity in phantoms modeling lymphatic flow.

  1. MACROSCOPIC RIVERS

    NARCIS (Netherlands)

    VANDENBERG, IP

    1991-01-01

    We present a mathematical model for the ''river-phenomenon'': striking concentrations of trajectories of ordinary differential equations. This model of ''macroscopic rivers'' is formulated within nonstandard analysis, and stated in terms of macroscopes and singular perturbations. For a subclass, the

  2. Interference of macroscopic superpositions

    CERN Document Server

    Vecchi, I

    2000-01-01

    We propose a simple experimental procedure based on the Elitzur-Vaidman scheme to implement a quantum nondemolition measurement testing the persistence of macroscopic superpositions. We conjecture that its implementation will reveal the persistence of superpositions of macroscopic objects in the absence of a direct act of observation.

  3. DC Magnetics Measurement System Design

    Science.gov (United States)

    Mastny, Timothy

    2012-01-01

    This report will detail the updates to the magnetics measurement system design and testing procedures that are required for performing static (DC) magnetics testing of future flight hardware. An older magnetics testing system had to be integrated with new procedures and hardware to meet the demands of future testing programs and accommodate an upcoming magnetics tests. The next test will be for the Geostationary Operational Environmental Satellite R-Series (GOES-R), which will verify that the SAFT Battery component meets its specifications for magnetic cleanliness. The satellite is scheduled to launch in 2015 with magnetics testing to be completed on the battery in November 2012.

  4. A Study of the Relationship between Macroscopic Measures and Physical Processes Occurring during N00014-89-J-1708.

    Science.gov (United States)

    1991-01-01

    The following personnel have worked on the project A. Principal Investigators 1. Stephen D. Antolovich Fracture Mechanics analytical studies...Physical Processes of Crack Closure of Al-Li Alloy 2090," T.M. Breunig, S.R. Stock, S.D. Antolovich , J.H. Kinney, W.N. Massey and M.C. Nichols, to appear in...Relating Macroscopic Measures and Physical Processes of Crack Closure of Al-Li Alloy 2090," T.M. Breunig, S.R. Stock, S.D. Antolovich , J.H. Kinney, W.N

  5. Measuring Earth's Magnetic Field Simply.

    Science.gov (United States)

    Stewart, Gay B.

    2000-01-01

    Describes a method for measuring the earth's magnetic field using an empty toilet paper tube, copper wire, clear tape, a battery, a linear variable resistor, a small compass, cardboard, a protractor, and an ammeter. (WRM)

  6. AA magnet measurement team

    CERN Multimedia

    1978-01-01

    Quickly improvised measurement equipment for the AA (Antiproton Accumulator) was all the tight schedule permitted, but the high motivation of the team made up for the lack of convenience. From left to right: Roy Billinge (Joint AA Project Leader, the other one was Simon van der Meer); Bruno Autin, Brian Pincott, Colin Johnson.

  7. Mu2e Magnetic Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Buehler, Marc [Fermilab; Tartaglia, Michael [Fermilab; Tompkins, John [Fermilab; Orozco, Charles [Illinois U., Urbana (main)

    2014-07-01

    The Mu2e experiment at Fermilab is designed to explore charged lepton flavor violation by searching for muon-to-electron conversion. The magnetic field generated by a system of solenoids is crucial for Mu2e and requires accurate characterization to detect any flaws and to produce a detailed field map. Stringent physics goals are driving magnetic field specifications for the Mu2e solenoids. A field mapper is being designed, which will produce detailed magnetic field maps. The uniform field region of the spectrometer volume requires the highest level of precision (1 Gauss per 1 Tesla). During commissioning, multiple magnetic field maps will be generated to verify proper alignment of all magnet coils, and to create the final magnetic field map. In order to design and build a precise field mapping system consisting of Hall and NRM probes, tolerances and precision for such a system need to be evaluated. In this paper we present a design for the Mu2e field mapping hardware, and discuss results from OPERA-3D simulations to specify parameters for Hall and NMR probes. We also present a fitting procedure for the analytical treatment of our expected magnetic measurements.

  8. Magnetic Cluster States in Nanostructured Materials

    Energy Technology Data Exchange (ETDEWEB)

    Diandra Leslie-Pelecky

    2008-06-13

    The goal of this work is to fabricate model nanomaterials with different types of disorder and use atomic-scale characterization and macroscopic magnetization measurements to understand better how specific types of disorder affects macroscopic magnetic behavior. This information can be used to produce magnetic nanomaterials with specific properties for applications such as permanent magnets, soft magnetic material for motors and biomedical applications.

  9. Hyaline cartilage thickness in radiographically normal cadaveric hips: comparison of spiral CT arthrographic and macroscopic measurements.

    Science.gov (United States)

    Wyler, Annabelle; Bousson, Valérie; Bergot, Catherine; Polivka, Marc; Leveque, Eric; Vicaut, Eric; Laredo, Jean-Denis

    2007-02-01

    To assess spiral multidetector computed tomographic (CT) arthrography for the depiction of cartilage thickness in hips without cartilage loss, with evaluation of anatomic slices as the reference standard. Permission to perform imaging studies in cadaveric specimens of individuals who had willed their bodies to science was obtained from the institutional review board. Two independent observers measured the femoral and acetabular hyaline cartilage thickness of 12 radiographically normal cadaveric hips (from six women and five men; age range at death, 52-98 years; mean, 76.5 years) on spiral multidetector CT arthrographic reformations and on coronal anatomic slices. Regions of cartilage loss at gross or histologic examination were excluded. CT arthrographic and anatomic measurements in the coronal plane were compared by using Bland-Altman representation and a paired t test. Differences between mean cartilage thicknesses at the points of measurement were tested by means of analysis of variance. Interobserver and intraobserver reproducibilities were determined. At CT arthrography, mean cartilage thickness ranged from 0.32 to 2.53 mm on the femoral head and from 0.95 to 3.13 mm on the acetabulum. Observers underestimated cartilage thickness in the coronal plane by 0.30 mm +/- 0.52 (mean +/- standard error) at CT arthrography (P cartilage thicknesses at the different measurement points was significant for coronal spiral multidetector CT arthrography and anatomic measurement of the femoral head and acetabulum and for sagittal and transverse CT arthrography of the femoral head (P cartilage thickness from the periphery to the center of the joint ("gradients") were found by means of spiral multidetector CT arthrography and anatomic measurement. Spiral multidetector CT arthrography depicts cartilage thickness gradients in radiographically normal cadaveric hips. (c) RSNA, 2007.

  10. 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.

  11. Transport in lymphatic capillaries. I. Macroscopic measurements using residence time distribution theory.

    Science.gov (United States)

    Swartz, M A; Berk, D A; Jain, R K

    1996-01-01

    We present a novel integrative method for characterizing transport in the lymphatic capillaries in the tail of the anesthetized mouse, which is both sensitive and reproducible for quantifying uptake and flow. Interstitially injected, fluorescently labeled macromolecules were used to visualize and quantify these processes. Residence time distribution (RTD) theory was employed to measure net flow velocity in the lymphatic network as well as to provide a relative measure of lymphatic uptake of macromolecules from the interstitium. The effects of particle size and injection pressure were determined. The uptake rate was found to be independent of particle size in the range of a 6- to 18-nm radius; beyond this size, the interstitial matrix seemed to pose a greater barrier. A comparison of 10 vs. 40 cmH2O injection pressure showed a significant influence on the relative uptake rate but not on the net velocity within the network (3.3 +/- 0.8 vs. 3.8 +/- 1.0 micron/s). This suggested the presence of a systemic driving force for baseline lymph propulsion that is independent of the local pressure gradients driving the uptake. This model can be used to examine various aspects of transport physiology of the initial lymphatics.

  12. Proposal for a macroscopic test of local realism with phase-space measurements

    Science.gov (United States)

    Arora, Atul S.; Asadian, Ali

    2015-12-01

    We propose a test of local realism based on correlation measurements of continuum valued functions of positions and momenta, known as modular variables. The Wigner representations of these observables are bounded in phase space and, therefore, the associated inequality holds for any state described by a non-negative Wigner function. This agrees with Bell's remark that positive Wigner functions, serving as a valid probability distribution over local (hidden) phase-space coordinates, do not reveal nonlocality. We construct a class of entangled states resulting in a violation of the inequality and thus truly demonstrate nonlocality in phase space. The states can be realized through grating techniques in spacelike separated interferometric setups. The nonlocality is verified from the spatial correlation data that is collected from the screens.

  13. Temperature Measurements in the Magnetic Measurement Facility

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, Zachary

    2010-12-13

    Several key LCLS undulator parameter values depend strongly on temperature primarily because of the permanent magnet material the undulators are constructed with. The undulators will be tuned to have specific parameter values in the Magnetic Measurement Facility (MMF). Consequently, it is necessary for the temperature of the MMF to remain fairly constant. Requirements on undulator temperature have been established. When in use, the undulator temperature will be in the range 20.0 {+-} 0.2 C. In the MMF, the undulator tuning will be done at 20.0 {+-} 0.1 C. For special studies, the MMF temperature set point can be changed to a value between 18 C and 23 C with stability of {+-}0.1 C. In order to ensure that the MMF temperature requirements are met, the MMF must have a system to measure temperatures. The accuracy of the MMF temperature measurement system must be better than the {+-}0.1 C undulator tuning temperature tolerance, and is taken to be {+-}0.01 C. The temperature measurement system for the MMF is under construction. It is similar to a prototype system we built two years ago in the Sector 10 alignment lab at SLAC. At that time, our goal was to measure the lab temperature to {+-}0.1 C. The system has worked well for two years and has maintained its accuracy. For the MMF system, we propose better sensors and a more extensive calibration program to achieve the factor of 10 increase in accuracy. In this note we describe the measurement system under construction. We motivate our choice of system components and give an overview of the system. Most of the software for the system has been written and will be discussed. We discuss error sources in temperature measurements and show how these errors have been dealt with. The calibration system is described in detail. All the LCLS undulators must be tuned in the Magnetic Measurement Facility at the same temperature to within {+-}0.1 C. In order to ensure this, we are building a system to measure the temperature of the

  14. Diagnosis of bladder tumours in patients with macroscopic haematuria: a prospective comparison of split-bolus computed tomography urography, magnetic resonance urography and flexible cystoscopy.

    Science.gov (United States)

    Gandrup, Karen L; Løgager, Vibeke B; Bretlau, Thomas; Nordling, Jørgen; Thomsen, Henrik S

    2015-06-01

    The aim of this study was to compare split-bolus computed tomography urography (CTU), magnetic resonance urography (MRU) and flexible cystoscopy in patients with macroscopic haematuria regarding the diagnosis of bladder tumours. In this prospective study, 150 patients underwent CTU, MRU and flexible cystoscopy. Two uroradiologists individually reviewed the images without any clinical information, using a questionnaire. Patient records and pathology reports were also reviewed. At flexible cystoscopy, MRU and CTU, 32, 19 and 15 bladder lesions were identified, respectively. Histopathology showed that 13 of the 29 biopsied lesions were transitional cell carcinomas. Compared with the histopathology, the sensitivity and specificity for detection of tumours by CTU and MRU were 61.5% and 94.9%, and 79.9% and 93.4%, respectively. False-positive detection of bladder tumours, compared with histopathology, was reported in seven CTUs and nine MRUs, whereas the number of false-negative findings was five for CTUs and three for MRUs. Split-bolus CTU or MRU cannot replace cystoscopy in cases of macroscopic haematuria. MRU has a higher sensitivity than split-bolus CTU, and is a potential alternative to flexible cystoscopy. Patients with a low risk of bladder cancer may forgo flexible cystoscopy if a bladder tumour is identified by either CTU or MRU, and proceed straight to transuretheral resection of the bladder.

  15. Magnetic measurements inside the Omicron magnet.

    CERN Multimedia

    1977-01-01

    The multipurpose detection system (Omicron) built at the SC in the late seventies in the Proton Hall made use of the large aperture magnet (on loan from Rutherford Lab, 85 cm gap height, 1 m width, 1.8 m length, 1 Tesla peak field). See CERN Courier 17 (1977) p. 61.

  16. Quantum equilibria for macroscopic systems

    Energy Technology Data Exchange (ETDEWEB)

    Grib, A [Department of Theoretical Physics and Astronomy, Russian State Pedagogical University, St. Petersburg (Russian Federation); Khrennikov, A [Centre for Mathematical Modelling in Physics and Cognitive Sciences Vaexjoe University (Sweden); Parfionov, G [Department of Mathematics, St. Petersburg State University of Economics and Finances (Russian Federation); Starkov, K [Department of Mathematics, St. Petersburg State University of Economics and Finances (Russian Federation)

    2006-06-30

    Nash equilibria are found for some quantum games with particles with spin-1/2 for which two spin projections on different directions in space are measured. Examples of macroscopic games with the same equilibria are given. Mixed strategies for participants of these games are calculated using probability amplitudes according to the rules of quantum mechanics in spite of the macroscopic nature of the game and absence of Planck's constant. A possible role of quantum logical lattices for the existence of macroscopic quantum equilibria is discussed. Some examples for spin-1 cases are also considered.

  17. Measurement system for SSRF pulsed magnets

    Institute of Scientific and Technical Information of China (English)

    PENG Chengcheng; GU Ming; LIU Bo; OUYANG Lianhua

    2007-01-01

    This paper describes the magnetic field measurement system for pulsed magnets in SSRF.The system consists of magnetic probes,analog active integrator,oscilloscope,stepper motor and a controller.An application program based on LabVIEW has been developed as main control unit.After the magnetic field mapping of a septum magnet prototype,it is verified that the test results accord with the results of theoretical calculation and computer simuladon.

  18. Estimation of strain from piezoelectric effect and domain switching in morphotropic PZT by combined analysis of macroscopic strain measurements and synchrotron X-ray data

    Energy Technology Data Exchange (ETDEWEB)

    Kungl, Hans [Institute of Ceramics in Mechanical Engineering, University of Karlsruhe, Haid-und-Neu-Str. 7, 76131 Karlsruhe (Germany)]. E-mail: hans.kungl@ikm.uni-karlsruhe.de; Theissmann, Ralf [Materials Science, Darmstadt University of Technology (Germany); Knapp, Michael [Materials Science, Darmstadt University of Technology (Germany); Baehtz, Carsten [Materials Science, Darmstadt University of Technology (Germany); Fuess, Hartmut [Materials Science, Darmstadt University of Technology (Germany); Wagner, Susanne [Institute of Ceramics in Mechanical Engineering, University of Karlsruhe, Haid-und-Neu-Str. 7, 76131 Karlsruhe (Germany); Fett, Theo [Institute of Ceramics in Mechanical Engineering, University of Karlsruhe, Haid-und-Neu-Str. 7, 76131 Karlsruhe (Germany); Hoffmann, Michael J. [Institute of Ceramics in Mechanical Engineering, University of Karlsruhe, Haid-und-Neu-Str. 7, 76131 Karlsruhe (Germany)

    2007-04-15

    Morphotropic PZT ceramics are State of the art materials for ferroelectric actuators. Essential performance parameters for these materials are strain and hysteresis. On a microscopic scale the strain provided by an electric field is due to two different mechanisms. The piezoelectric effect causes an elongation of the unit cells, whereas domain switching changes their crystallographic orientation by aligning the polarization axis towards the field direction. A method is outlined to estimate the contribution of the two mechanisms to total strain by combining macroscopic strain measurements and X-ray diffraction (XRD) data. Results from macroscopic measurements of remanent and unipolar strain with the corresponding data on texture, derived from in situ synchrotron radiation XRD patterns, are analyzed and evaluated by a semi-empirical approach. The method was applied to six morphotropic, LaSr doped PZT materials of different Zr/Ti ratios. Results are discussed with respect to the differences between the materials.

  19. Granular superconductivity and magnetic-field-driven recovery of macroscopic coherence in a cuprate/manganite multilayer

    OpenAIRE

    Mallett, B. P. P.; Khmaladze, J.; Marsik, P.; Perret, E.; Cerreta, A.; Orlita, M.; Biškup, N.; Varela, M.; Bernhard, C.

    2015-01-01

    We show that in Pr$ _{0.5} $La$ _{0.2} $Ca$ _{0.3} $MnO$ _{3} $/YBa$ _{2} $Cu$ _{3} $O$ _{7} $ (PLCMO/YBCO) multilayers the low temperature state of YBCO is very resistive and resembles the one of a granular superconductor or a frustrated Josephson-junction network. Notably, a coherent superconducting response can be restored with a large magnetic field which also suppresses the charge-orbital order in PLCMO. This coincidence suggests that the granular superconducting state of YBCO is induced...

  20. Granular superconductivity and magnetic-field-driven recovery of macroscopic coherence in a cuprate/manganite multilayer

    Science.gov (United States)

    Mallett, B. P. P.; Khmaladze, J.; Marsik, P.; Perret, E.; Cerreta, A.; Orlita, M.; Biškup, N.; Varela, M.; Bernhard, C.

    2016-11-01

    We show that in Pr0.5La0.2Ca0.3MnO3 /YBa2Cu3O7 (PLCMO/YBCO) multilayers the low temperature state of YBCO is very resistive and resembles that of a granular superconductor or a frustrated Josephson-junction network. Notably, a coherent superconducting response can be restored with a large magnetic field which also suppresses the charge-orbital order in PLCMO. This coincidence suggests that the granular superconducting state of YBCO is induced by the charge-orbital order of PLCMO. The coupling mechanism and the nature of the induced inhomogeneous state in YBCO remain to be understood.

  1. Magnet measuring equipment of SC2

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    Checking the positioning of the magnet measuring equipment installed between the poles of SC2. The steel structure in front of the magnet is designed to house the rotary condenser and to shield it from the stray magnetic field of the accelerator.

  2. Magnet measuring equipment of SC2

    CERN Multimedia

    1974-01-01

    Checking the positioning of the magnet measuring equipment installed between the poles of SC2. The steel structure in front of the magnet is designed to house the rotary condenser and to shield it from the stray magnetic field of the accelerator. On the left, Marinus van Gulik. (See Photo Archive 7402005 and Annual Report 1974, p. 44.)

  3. Automatic magnetic flux measurement of micro plastic-magnetic rotors

    Science.gov (United States)

    Wang, Qingdong; Lin, Mingxing; Song, Aiwei

    2015-07-01

    Micro plastic-magnetic rotors of various sizes and shapes are widely used in industry, their magnetic flux measurement is one of the most important links in the production process, and therefore some technologies should be adopted to improve the measurement precision and efficiency. In this paper, the automatic measurement principle of micro plastic-magnetic rotors is proposed and the integration time constant and the integrator drift’s suppression and compensation in the measurement circuit are analyzed. Two other factors influencing the measurement precision are also analyzed, including the relative angles between the rotor magnetic poles and the measurement coil, and the starting point of the rotors in the coil where the measurement begins. An instrument is designed to measure the magnetic flux of the rotors. Measurement results show that the measurement error is within  ±1%, which meets the basic requirements in industry application, and the measurement efficiency is increased by 10 times, which can cut down labor cost and management cost when compared with manual measurement.

  4. Real time measurement of plasma macroscopic parameters on RFX-mod using a limited set of sensors

    Science.gov (United States)

    Kudlacek, Ondrej; Zanca, Paolo; Finotti, Claudio; Marchiori, Giuseppe; Cavazzana, Roberto; Marrelli, Lionello

    2015-10-01

    A method to estimate the plasma boundary and global parameters such as βp+li/2 and the edge safety factor q95 is described. The method is based on poloidal flux extrapolation in the vacuum region between the plasma and the magnetic measurements, and it is efficient and accurate even if a limited set of sensors is used. The discrepancy between the plasma boundary provided by this method and the boundary computed by the Grad-Shafranov solver MAXFEA is lower than 8 mm in all the considered cases. Moreover, the method is robust against the noise level present in the RFX-mod measurements. The difference between the estimated global parameters and the MAXFEA simulation results is lower than 4%. The method was finally implemented in the RFX-mod shape control system, working at 5 kHz cycle frequency, to provide a reliable set of plasma-wall distances (gaps) used as feedback signals. Experimental results obtained in one year of RFX-mod operation are shown.

  5. HELMHOLTZ COILS FOR MEASURING MAGNETIC MOMENTS

    Directory of Open Access Journals (Sweden)

    P. N. Dobrodeyev

    2013-01-01

    Full Text Available The optimal configuration of the double Helmholtz coils for measuring of the magnetic dipole moments was defined. It was determined that measuring coils should have round shape and compensative coils – the square one. Analytically confirmed the feasibility of the proposed configuration of these coils as primary transmitters of magnetic dipole moments.

  6. Measuring magnetic correlations in nanoparticle assemblies

    DEFF Research Database (Denmark)

    Beleggia, Marco; Frandsen, Cathrine

    2014-01-01

    We illustrate how to extract correlations between magnetic moments in assemblies of nanoparticles from, e.g., electron holography data providing the combined knowledge of particle size distribution, inter-particle distances, and magnitude and orientation of each magnetic moment within...... a nanoparticle superstructure, We show, based on simulated data, how to build a radial/angular pair distribution function f(r,θ) encoding the spatial and angular difference between every pair of magnetic moments. A scatter-plot of f(r,θ) reveals the degree of structural and magnetic order present, and hence...... provides a measure of the strength and range of magnetic correlations....

  7. Direct measurements of the magnetic entropy change

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein; Neves Bez, Henrique; von Moos, Lars

    2015-01-01

    An experimental device that can accurately measure the magnetic entropy change, Δs, as a function of temperature, T, and magnetic field, H, is presented. The magnetic field source is in this case a set of counter-rotating concentric Halbach-type magnets, which produce a highly homogeneous applied...... to the ambient are negligible in terms of the calorimetric determination of the magnetic entropy change, while the losses cannot be ignored when correcting for the actual sample temperature. We apply the device to two different types of samples; one is commercial grade Gd, i.e., a pure second-order phase...

  8. A Flexible Framework for Magnetic Measurements

    CERN Document Server

    Inglese, V; Buzio, M

    2009-01-01

    The work presented in this Ph.D. thesis covers the specification, design, prototyping, and validation of a new version of a magnetic measurement control, acquisition, and data analysis software package: the Flexible Framework for Magnetic Measurements (FFMM). FFMM constitutes the software part of the new platform for magnetic measurements, including also new high-performance hardware, developed at the European Organization for Nuclear Research (CERN) in cooperation with the Department of Engineering of the University of Sannio. FFMM is conceived as a unified solution to drive all the existing and future park of measurement systems (mainly magnetic but also optical, mechanical, etc.). The effort for the series test of the LHC superconducting magnets highlighted limitations in the measurement control and acquisition programs, mainly associated with the relatively long time needed for a development iteration (the cycle of specification-programming-debugging-validation). Moreover, the software capabilities needed...

  9. Measurement of magnetic moment via optical transmission

    Energy Technology Data Exchange (ETDEWEB)

    Heidsieck, Alexandra, E-mail: aheidsieck@tum.de; Schmid, Daniel; Gleich, Bernhard

    2016-03-01

    The magnetic moment of nanoparticles is an important property for drug targeting and related applications as well as for the simulation thereof. However, the measurement of the magnetic moment of nanoparticles, nanoparticle–virus-complexes or microspheres in solution can be difficult and often yields unsatisfying or incomparable results. To measure the magnetic moment, we designed a custom measurement device including a magnetic set-up to observe nanoparticles indirectly via light transmission in solution. We present a simple, cheap device of manageable size, which can be used in any laboratory as well as a novel evaluation method to determine the magnetic moment of nanoparticles via the change of the optical density of the particle suspension in a well-defined magnetic gradient field. In contrast to many of the established measurement methods, we are able to observe and measure the nanoparticle complexes in their natural state in the respective medium. The nanoparticles move along the magnetic gradient and thereby away from the observation point. Due to this movement, the optical density of the fluid decreases and the transmission increases over time at the measurement location. By comparing the measurement with parametric simulations, we can deduce the magnetic moment from the observed behavior. - Highlights: • Performance of a direct detection camera in the context of off-axis electron holography has been evaluated. • A measurement device to indirectly observe magnetic nanoparticles (MNPs) is described. • MNPs can be observed in the respective medium via light transmission. • An evaluation method to determine the magnetic moment of the MNPs is presented. • The magnetic moment can be deduced from the observed change in optical density.

  10. Magnetic induction measurements in distribution transformer cores

    Energy Technology Data Exchange (ETDEWEB)

    Paraskevopoulos, A.A.P.; Bourkas, P.D. [National Technical Univ. of Athens, Athens (Greece). Computer Engineering, High Voltage, and Electrical Measurements Laboratory; Paparigas, D. [Schneider ELVIM Electric Transformer Factory, Athens (Greece)

    2005-07-01

    Transformers need high magnetic field rates in order to operate efficiently. In this study, magnetic induction measurements of distribution transformer cores with power levels of 630 kVA were used to assess the performance of transformers in a city in Greece. A 630 kVA transformer was used to investigate whether magnetic induction measurements of the iron core arcs of the transformer were similar to the rest of the transformer's magnetic rate. Potential load losses were also investigated. Eight cores of 4 different sizes were measured in the study. Voltage transmissions were varied in order to measure the different cores. The voltage transmitted into the coil was calculated in order to compare the transformer's magnetic field with the cores. Average values for the measured cores were then calculated. Leakages were measured using a Gauss meter. Results of the study indicated that the measured values were lower than established safety limits for transformers. It was concluded that the magnetic induction measurements of transformer cores can be used to measure the overall performance of transformers. 18 refs., 8 tabs., 5 figs.

  11. The macroscopic pancake bounce

    Science.gov (United States)

    Andersen Bro, Jonas; Sternberg Brogaard Jensen, Kasper; Nygaard Larsen, Alex; Yeomans, Julia M.; Hecksher, Tina

    2017-01-01

    We demonstrate that the so-called pancake bounce of millimetric water droplets on surfaces patterned with hydrophobic posts (Liu et al 2014 Nat. Phys. 10 515) can be reproduced on larger scales. In our experiment, a bed of nails plays the role of the structured surface and a water balloon models the water droplet. The macroscopic version largely reproduces the features of the microscopic experiment, including the Weber number dependence and the reduced contact time for pancake bouncing. The scalability of the experiment confirms the mechanisms of pancake bouncing, and allows us to measure the force exerted on the surface during the bounce. The experiment is simple and inexpensive and is an example where front-line research is accessible to student projects.

  12. Usefulness of combining gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging and contrast-enhanced ultrasound for diagnosing the macroscopic classification of small hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Tomoki; Aikata, Hiroshi; Hatooka, Masahiro; Morio, Kei; Morio, Reona; Kan, Hiromi; Fujino, Hatsue; Fukuhara, Takayuki; Masaki, Keiichi; Ohno, Atsushi; Naeshiro, Noriaki; Nakahara, Takashi; Honda, Yohji; Murakami, Eisuke; Kawaoka, Tomokazu; Tsuge, Masataka; Hiramatsu, Akira; Imamura, Michio; Kawakami, Yoshiiku; Hyogo, Hideyuki; Takahashi, Shoichi [Hiroshima University Hospital, Department of Gastroenterology and Metabolism, Hiroshima (Japan); Chayama, Kazuaki [Hiroshima University Hospital, Department of Gastroenterology and Metabolism, Hiroshima (Japan); Hiroshima University, Liver Research Project Center, Hiroshima (Japan)

    2015-11-15

    Non-simple nodules in hepatocellular carcinoma (HCC) correlate with poor prognosis. Therefore, we examined the diagnostic ability of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) and contrast-enhanced ultrasound (CEUS) for diagnosing the macroscopic classification of small HCCs. A total of 85 surgically resected nodules (≤30 mm) were analyzed. HCCs were pathologically classified as simple nodular (SN) and non-SN. By evaluating hepatobiliary phase (HBP) of EOB-MRI and Kupffer phase of CEUS, the diagnostic abilities of both modalities to correctly distinguish between SN and non-SN were compared. Forty-six nodules were diagnosed as SN and the remaining 39 nodules as non-SN. The area under the ROC curve (AUROCs, 95 % confidence interval) for the diagnosis of non-SN were EOB-MRI, 0.786 (0.682-0.890): CEUS, 0.784 (0.679-0.889), in combination, 0.876 (0.792-0.959). The sensitivity, specificity, and accuracy were 64.1 %, 95.7 %, and 81.2 % in EOB-MRI, 56.4 %, 97.8 %, and 78.8 % in CEUS, and 84.6 %, 95.7 %, and 90.6 % in combination, respectively. High diagnostic ability was obtained when diagnosed in both modalities combined. The sensitivity was especially statistically significant compared to CEUS. Combined diagnosis by EOB-MRI and CEUS can provide high-quality imaging assessment for determining non-SN in small HCCs. (orig.)

  13. Magnetic Linear Birefringence Measurements Using Pulsed Fields

    CERN Document Server

    Berceau, Paul; Battesti, Remy; Rizzo, Carlo

    2011-01-01

    In this paper we present the accomplishment of the further step towards the vacuum magnetic birefringence measurement based on pulsed fields. After describing our BMV experiment, we report the calibration of our apparatus with nitrogen gas and we discuss the precision of our measurement giving a detailed error budget. Our best present vacuum sensitivity is 2.1x 10^-19 T^-2 per 5 ms magnetic pulse. We finally discuss the perspectives to reach our final goal.

  14. Accuracy of magnetic resonance based susceptibility measurements

    Science.gov (United States)

    Erdevig, Hannah E.; Russek, Stephen E.; Carnicka, Slavka; Stupic, Karl F.; Keenan, Kathryn E.

    2017-05-01

    Magnetic Resonance Imaging (MRI) is increasingly used to map the magnetic susceptibility of tissue to identify cerebral microbleeds associated with traumatic brain injury and pathological iron deposits associated with neurodegenerative diseases such as Parkinson's and Alzheimer's disease. Accurate measurements of susceptibility are important for determining oxygen and iron content in blood vessels and brain tissue for use in noninvasive clinical diagnosis and treatment assessments. Induced magnetic fields with amplitude on the order of 100 nT, can be detected using MRI phase images. The induced field distributions can then be inverted to obtain quantitative susceptibility maps. The focus of this research was to determine the accuracy of MRI-based susceptibility measurements using simple phantom geometries and to compare the susceptibility measurements with magnetometry measurements where SI-traceable standards are available. The susceptibilities of paramagnetic salt solutions in cylindrical containers were measured as a function of orientation relative to the static MRI field. The observed induced fields as a function of orientation of the cylinder were in good agreement with simple models. The MRI susceptibility measurements were compared with SQUID magnetometry using NIST-traceable standards. MRI can accurately measure relative magnetic susceptibilities while SQUID magnetometry measures absolute magnetic susceptibility. Given the accuracy of moment measurements of tissue mimicking samples, and the need to look at small differences in tissue properties, the use of existing NIST standard reference materials to calibrate MRI reference structures is problematic and better reference materials are required.

  15. Magnetic Signals of High-Temperature Superconductor Bulk During the Levitation Force Measurement Process

    Science.gov (United States)

    Huang, Huan; Zheng, Jun; Qian, Nan; Che, Tong; Zheng, Botian; Jin, Liwei; Deng, Zigang

    2017-05-01

    In order to study the commonly neglected magnetic field information in the course of levitation force measurement process in a superconducting maglev system, a multipoint magnetic field measurement platform was employed to acquire magnetic signals of a bulk high-Tc superconductor on both the top and the bottom surface. Working conditions including field cooling (FC) and zero field cooling were investigated for these vertical down and up motions above a permanent magnet guideway performed on a HTS maglev measurement system. We have discussed the magnetic flux variation process based on the Bean model. A magnetic hysteresis effect similar to the levitation force hysteresis loop of the bulk superconductor was displayed and analyzed in this paper. What is more valuable, there exists some available magnetic flux on the top surface of the bulk superconductor, and the proportion is as high as 62.42% in the FC condition, which provides an experimental hint to design the superconductor bulk and the applied field for practical use in a more efficient way. In particular, this work reveals real-time magnetic flux variation of the bulk superconductor in the levitation application, which is the other important information in contrast to the macroscopic levitation and guidance force investigations in previous studies, and it enriches the existing research methods. The results are significant for understanding the magnetic characteristic of superconductors, and they can contribute to optimize the present HTS maglev system design.

  16. Magnetic Signals of High-Temperature Superconductor Bulk During the Levitation Force Measurement Process

    Science.gov (United States)

    Huang, Huan; Zheng, Jun; Qian, Nan; Che, Tong; Zheng, Botian; Jin, Liwei; Deng, Zigang

    2017-02-01

    In order to study the commonly neglected magnetic field information in the course of levitation force measurement process in a superconducting maglev system, a multipoint magnetic field measurement platform was employed to acquire magnetic signals of a bulk high-Tc superconductor on both the top and the bottom surface. Working conditions including field cooling (FC) and zero field cooling were investigated for these vertical down and up motions above a permanent magnet guideway performed on a HTS maglev measurement system. We have discussed the magnetic flux variation process based on the Bean model. A magnetic hysteresis effect similar to the levitation force hysteresis loop of the bulk superconductor was displayed and analyzed in this paper. What is more valuable, there exists some available magnetic flux on the top surface of the bulk superconductor, and the proportion is as high as 62.42% in the FC condition, which provides an experimental hint to design the superconductor bulk and the applied field for practical use in a more efficient way. In particular, this work reveals real-time magnetic flux variation of the bulk superconductor in the levitation application, which is the other important information in contrast to the macroscopic levitation and guidance force investigations in previous studies, and it enriches the existing research methods. The results are significant for understanding the magnetic characteristic of superconductors, and they can contribute to optimize the present HTS maglev system design.

  17. Measurement of anomalous resistance induced by chaotic motion of electrons in a magnetic null point

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Keita; Yoshida, Zensho; Himura, Haruhiko; Morikawa, Junji; Nakashima, Chihiro; Saitoh, Haruhiko; Tahara, Shigeru; Fukao, Masayuki [Tokyo Univ., Graduate School of Frontier Sciences, Tokyo (Japan); Uchida, Taijiro [ULVAC Japan, Ltd. Hagisono, Chigasaki, Kanagawa (Japan)

    2001-07-01

    Chaotic motion of particle in magnetic null regions can produce a large collisionless resistivity. In order to measure the macroscopic resistivity, a new instrument using a Pockels crystal has been developed. This measurement can detect a high frequency electric field in plasmas. The Pockels probe satisfies the frequency response with 13.56 MHz and the sensitivity as low as 3x10{sup 2} V/m, which proves the capability of measuring the local electric fields in a plasma discharged by a radio-frequency method. (author)

  18. Magnet Fiducialization with Coordinate Measuring Machines

    Energy Technology Data Exchange (ETDEWEB)

    Friedsam, H.; Oren, W.; Pietryka, M.; /SLAC

    2005-08-12

    One of the fundamental alignment problems encountered when building a particle accelerator is the transfer of a component's magnetic centerline position to external fiducials. This operation, dubbed fiducialization, is critical because it can contribute significantly to the alignment error budget. The fiducialization process requires two measurements: (1) from magnetic centerline to mechanical centerline, and (2) from mechanical centerline to external fiducials. This paper will focus on methods for observing the second measurement. Two Stanford Linear Collider (SLC) examples are presented. The object of magnet fiducialization is to relate the magnet-defined beamline position to exterior reference surfaces. To be useful for later component alignment, this relationship must be established in a manner consistent with overall positioning tolerances. The error budget for the SLC's {+-} 100 {micro}m component to component alignment tolerance is as follows: magnetic centerline to mechanical centerline--{sigma} = {+-}30 {micro}m; mechanical centerline to fiducial marks--{sigma} = {+-}50 {micro}m; and fiducial marks to adjacent components--{sigma} = {+-}80 {micro}m; the TOTAL {sigma} = {+-}100 {micro}m. The offset between the mechanical and magnetic centerlines of well-known magnets is generally smaller than the {+-}30 {micro}m measurement tolerance. It is commonly assumed to be zero without measurement. When this tiny value must be measured, extreme care is necessary to avoid obscuring the offset with measurement tool registration errors. In contrast, the mechanical centerline to fiducial measurement must be performed on every magnet. The 50 {micro}m tolerance for this operation is only slightly larger and pushes conventional surveying technology to its limit.

  19. Pressure measurements in magnetic-fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Dylla, H.F.

    1981-11-01

    Accurate pressure measurements are important in magnetic fusion devices for: (1) plasma diagnostic measurements of particle balance and ion temperature; (2) discharge cleaning optimization; (3) vacuum system performance; and (4) tritium accountability. This paper reviews the application, required accuracy, and suitable instrumentation for these measurements. Demonstrated uses of ionization-type and capacitance-diaphragm gauges for various pressure and gas-flow measurements in tokamaks are presented, with specific reference to the effects of magnetic fields on gauge performance and the problems associated with gauge calibration.

  20. Magnetization measurements reveal the local shear stiffness of hydrogels probed by ferromagnetic nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Bender, P., E-mail: nano@p-bender.de; Tschöpe, A., E-mail: antsch@mx.uni-saarland.de; Birringer, R., E-mail: r.birringer@nano.uni-saarland.de

    2014-12-15

    The local mechanical coupling of ferromagnetic nanorods in hydrogels was characterized by magnetization measurements. Nickel nanorods were synthesized by the AAO-template method and embedded in gelatine hydrogels with mechanically soft or hard matrix properties determined by the gelatine weight fraction. By applying a homogeneous magnetic field during gelation the nanorods were aligned along the field resulting in uniaxially textured ferrogels. The magnetization curves of the soft ferrogel exhibited not only important similarities but also characteristic differences as compared to the hard ferrogel. The hystereses measured in a field parallel to the texture axis were almost identical for both samples indicating effective coupling of the nanorods with the polymer network. By contrast, measurements in a magnetic field perpendicular to the texture axis revealed a much higher initial susceptibility of the soft as compared to the hard ferrogel. This difference was attributed to the additional rotation of the nanorods allowed by the reduced shear modulus in the soft ferrogel matrix. Two methods for data analysis were presented which enabled us to determine the shear modulus of the gelatine matrix which was interpreted as a local rather than macroscopic quantity in consideration of the nanoscale of the probe particles. - Highlights: • Nanorods are embedded as magnetic probes in gelatine gels. • Elastic rotation of the rods can be induced by applying a homogeneous magnetic field. • Rod rotation has significant influence on the magnetization curves. • Two methods are presented to estimate the shear modulus of the matrix from the magnetization curves.

  1. Magnetization measurements on LHC superconducting strands

    CERN Document Server

    Le Naour, S; Wolf, R; Puzniak, R; Szewczyk, A; Wisniewski, A; Fikis, H; Foitl, M; Kirchmayr, H

    1999-01-01

    When using superconducting magnets in particle accelerators like the LHC, persistent currents in the superconductor often determine the field quality at injection, where the magnetic field is low. This paper describes magnetization measurements made on LHC cable strands at the Technical University of Vienna and the Institute of Physics of the Polish Academy of Sciences in collaboration with CERN. Measurements were performed at T=2 K and T=4.2 K on more than 50 strands of 7 different manufacturers with NbTi filament diameter between 5 and 7 micrometer. Two different measurement set-ups were used: vibrating sample magnetometer, with a sample length of about 8 mm, and an integrating coil magnetometer, with sample length of about 1 m. The two methods were compared by measuring the same sample. Low field evidence of proximity effect is discussed. Statistics like ratio of the width of the magnetization loop at 4.2 K 2 K, and the initial slope dM/dB after cooldown are presented. Decrease of the magnetization with ti...

  2. Warm Magnetic Field Measurements of LARP HQ Magnet

    Energy Technology Data Exchange (ETDEWEB)

    Caspi, S; Cheng, D; Deitderich, D; Felice, H; Ferracin, P; Hafalia, R; Joseph, J; Lizarazo, J; Martchevskii, M; Nash, C; Sabbi, G L; Vu, C; Schmalzle, J; Ambrosio, G; Bossert, R; Chlachidze, G; DiMarco, J; Kashikhin, V

    2011-03-28

    The US-LHC Accelerator Research Program is developing and testing a high-gradient quadrupole (HQ) magnet, aiming at demonstrating the feasibility of Nb{sub 3}Sn technologies for the LHC luminosity upgrade. The 1 m long HQ magnet has a 120 mm bore with a conductor-limited gradient of 219 T/m at 1.9 K and a peak field of 15 T. HQ includes accelerator features such as alignment and field quality. Here we present the magnetic measurement results obtained at LBNL with a constant current of 30 A. A 100 mm long circuit-board rotating coil developed by FNAL was used and the induced voltage and flux increment were acquired. The measured b{sub 6} ranges from 0.3 to 0.5 units in the magnet straight section at a reference radius of 21.55 mm. The data reduced from the numerical integration of the raw voltage agree with those from the fast digital integrators.

  3. Magnetic Field Measurement on a Refined Kicker

    CERN Document Server

    Fan, Tai-Ching; Lin, Fu-Yuan

    2005-01-01

    To prepare for the operation of top-up mode and increase the efficiency of injection at storage ring, National Synchrotron Radiation Research Center (NSRRC) has upgraded the kicker magnets and power supply. We have built up a new magnetic field measurement system to test the kicker. This system, including a search coil and a coil loop, can map the field and take the first integral of field automatically. We also simulate the trajectory of electron beam by pulsed wire method of field measurement. We analyze the performance of the kicker system in this paper.

  4. Temperature dependent nonlinear Hall effect in macroscopic Si-MOS antidot array

    OpenAIRE

    Kuntsevich, A. Yu.; Shupltetsov, A. V.; Nunuparov, M. S.

    2015-01-01

    By measuring magnetoresistance and Hall effect in classically moderate perpendicular magnetic field in Si-MOSFET-type macroscopic antidot array we found a novel effect: nonlinear with field, temperature- and density-dependent Hall resistivity. We discuss qualitative explanation of the phenomenon and suggest that it might originate from strong temperature dependence of the resistivity and mobility in the shells of the antidots.

  5. Measurements of Photospheric and Chromospheric Magnetic Fields

    Science.gov (United States)

    Lagg, Andreas; Lites, Bruce; Harvey, Jack; Gosain, Sanjay; Centeno, Rebecca

    2017-09-01

    The Sun is replete with magnetic fields, with sunspots, pores and plage regions being their most prominent representatives on the solar surface. But even far away from these active regions, magnetic fields are ubiquitous. To a large extent, their importance for the thermodynamics in the solar photosphere is determined by the total magnetic flux. Whereas in low-flux quiet Sun regions, magnetic structures are shuffled around by the motion of granules, the high-flux areas like sunspots or pores effectively suppress convection, leading to a temperature decrease of up to 3000 K. The importance of magnetic fields to the conditions in higher atmospheric layers, the chromosphere and corona, is indisputable. Magnetic fields in both active and quiet regions are the main coupling agent between the outer layers of the solar atmosphere, and are therefore not only involved in the structuring of these layers, but also for the transport of energy from the solar surface through the corona to the interplanetary space. Consequently, inference of magnetic fields in the photosphere, and especially in the chromosphere, is crucial to deepen our understanding not only for solar phenomena such as chromospheric and coronal heating, flares or coronal mass ejections, but also for fundamental physical topics like dynamo theory or atomic physics. In this review, we present an overview of significant advances during the last decades in measurement techniques, analysis methods, and the availability of observatories, together with some selected results. We discuss the problems of determining magnetic fields at smallest spatial scales, connected with increasing demands on polarimetric sensitivity and temporal resolution, and highlight some promising future developments for their solution.

  6. Summary of HQ01e magnetic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Caspi, S.; Cheng, D. W.; Dietderich, D. R.; Felice, H.; Ferracin, P.; Godeke, A.; Hafalia, A.R.; Joseph, J. M.; Lizarazo, J.; Marchevsky, M.; Sabbi, G. L.; Ghosh, A.; Schmalzle, J.; Wanderer, P.; Ambrosio, G.; Bossert, R.; Chlachidze, G.; DiMarco, J.; Zlobin, A.V.; Milanese, A.; Todesco, E.

    2011-11-28

    The magnetic measurements of HQ01e, a 1 m long LHC Accelerator Research Program (LARP) high-gradient quadrupole model, were performed at 4.4 K and above 40 K at the magnet test facility of LBNL in July 2011. The 120 mm aperture cos2θ Nb{sub 3}Sn magnet was designed with accelerator magnet features including alignment and field quality. Conductor-limited gradient was 195 T/m at 4.4 K. During the measurement, a ramp rate of 10 A/s was used and measurements at the nominal current of 14.2 kA (82% of short-sample limit with a gradient of 160 T/m) were performed using the 250 mm long printed-circuit board rotating probe developed by FNAL. At 14.2 kA, 2.7 units of b{sub 6} and 0.7 units of b{sub 10} were measured. Large persistent current contribution and strong dynamic effects were observed. We analyzed the allowed and non-allowed harmonics obtained during the measurements above 40 K and at the nominal current. Significant change of the skew sextupole occurred between 50 K and 95 K. The allowed multipole and the low-order non-allowed multipoles at the straight section were explained through the rigid displacement of coil blocks with an amplitude less than 100 μm. We also attempted to correlate the coil asymmetry (a{sub 3} and b{sub 3}) with the measured coil pole azimuthal strain. The dynamic multipole measured at the magnetic straight section varied linearly with the ramp rate of magnet current ranging from 10 A/s to 60 A/s. It was attributed to the inter-strand coupling currents with low crossover resistance. The crossover resistance of the cables at the inner layer of the magnet was estimated to range between 0.2 μΩ to 0.7 μΩ.

  7. Gravimetric Measurement of Magnetic Field Gradient Spatial Distribution

    CERN Document Server

    Arutunian, S G; Egiazarian, S L; Mailian, M R; Sinenko, I G; Sinjavski, A V; Vasiniuk, I E

    1999-01-01

    Magnetic interaction between a weighing sample and an external magnetic field allows to measure characteristics of magnetic field (a sample with known magnetic characteristics), as well as the magnetic properties of a sample (a known magnetic field). Measurement of materials magnetic permeability is a well known application of this method. In this paper we restrict ourselves to the measurement of magnetic field spatial distribution, which was achieved by scanning of samples from known materials along the vertical axis. Field measurements by Hall detector were done to calibrate obtained data. Such measurements are of great interest in some branches of physics, in particular, in accelerator physics, where the quality of magnetic system parts eventually determine the quality of accelerated bunches. Development of a simple and cheep device for measurement of magnetic field spatial distribution is an urgent problem. The developed system for gravimetric measurement of magnetic field gradients partially solves this ...

  8. Macroscopic quantum resonators (MAQRO)

    CERN Document Server

    Kaltenbaek, Rainer; Kiesel, Nikolai; Romero-Isart, Oriol; Johann, Ulrich; Aspelmeyer, Markus

    2012-01-01

    Quantum physics challenges our understanding of the nature of physical reality and of space-time and suggests the necessity of radical revisions of their underlying concepts. Experimental tests of quantum phenomena involving massive macroscopic objects would provide novel insights into these fundamental questions. Making use of the unique environment provided by space, MAQRO aims at investigating this largely unexplored realm of macroscopic quantum physics. MAQRO has originally been proposed as a medium-sized fundamental-science space mission for the 2010 call of Cosmic Vision. MAQRO unites two experiments: DECIDE (DECoherence In Double-Slit Experiments) and CASE (Comparative Acceleration Sensing Experiment). The main scientific objective of MAQRO, which is addressed by the experiment DECIDE, is to test the predictions of quantum theory for quantum superpositions of macroscopic objects containing more than 10e8 atoms. Under these conditions, deviations due to various suggested alternative models to quantum th...

  9. Space-resolved diffusing wave spectroscopy measurements of the macroscopic deformation and the microscopic dynamics in tensile strain tests

    Science.gov (United States)

    Nagazi, Med-Yassine; Brambilla, Giovanni; Meunier, Gérard; Marguerès, Philippe; Périé, Jean-Noël; Cipelletti, Luca

    2017-01-01

    We couple a laser-based, space-resolved dynamic light scattering apparatus to a universal traction machine for mechanical extensional tests. We perform simultaneous optical and mechanical measurements on polyether ether ketone, a semi-crystalline polymer widely used in the industry. Due to the high turbidity of the sample, light is multiply scattered by the sample and the diffusing wave spectroscopy (DWS) formalism is used to interpret the data. Space-resolved DWS yields spatial maps of the sample strain and of the microscopic dynamics. An excellent agreement is found between the strain maps thus obtained and those measured by a conventional stereo-digital image correlation technique. The microscopic dynamics reveals both affine motion and plastic rearrangements. Thanks to the extreme sensitivity of DWS to displacements as small as 1 nm, plastic activity and its spatial localization can be detected at an early stage of the sample strain, making the technique presented here a valuable complement to existing material characterization methods.

  10. Lightning Magnetic Field Measurements around Langmuir Laboratory

    Science.gov (United States)

    Stock, M.; Krehbiel, P. R.; Rison, W.; Aulich, G. D.; Edens, H. E.; Sonnenfeld, R. G.

    2010-12-01

    In the absence of artificial conductors, underground lightning transients are produced by diffusion of the horizontal surface magnetic field of a return stroke vertically downward into the conducting earth. The changing magnetic flux produces an orthogonal horizontal electric field, generating a dispersive, lossy transverse electromagnetic wave that penetrates a hundred meters or more into the ground according to the skin depth of the medium. In turn, the electric field produces currents that flow toward or away from the channel to ground depending on the stroke polarity. The underground transients can produce large radial horizontal potential gradients depending on the distance from the discharge and depth below the surface. In this study we focus on the surface excitation field. The goal of the work is to compare measurements of surface magnetic field waveforms B(t) at different distances from natural lightning discharges with simple and detailed models of the return stroke fields. In addition to providing input to the diffusion mechanism, the results should aid in further understanding return stroke field generation processes. The observational data are to be obtained using orthogonal sets of straightened Rogowski coils to measure magnetic field waveforms in N-S and E-W directions. The waveforms are sampled at 500 kS/s over 1.024 second time intervals and recorded directly onto secure digital cards. The instrument operates off of battery power for several days or weeks at a time in remote, unattended locations and measures magnetic field strengths of up to several tens of amperes/meter. The observations are being made in conjunction with collocated slow electric field change measurements and under good 3-D lightning mapping array (LMA) and fast electric field change coverage.

  11. A Magnetic Resonance Measurement Technique for Rapidly Switched Gradient Magnetic Fields in a Magnetic Resonance Tomograph

    Directory of Open Access Journals (Sweden)

    K. Bartušek

    2003-01-01

    Full Text Available This paper describes a method for measuring of the gradient magnetic field in Nuclear Magnetic Resonance (NMR tomography, which is one of the modern medical diagnostic methods. A very important prerequisite for high quality imaging is a gradient magnetic field in the instrument with exactly defined properties. Nuclear magnetic resonance enables us to measure the pulse gradient magnetic field characteristics with high accuracy. These interesting precise methods were designed, realised, and tested at the Institute of Scientific Instruments (ISI of the Academy of Sciences of the Czech Republic. The first of them was the Instantaneous Frequency (IF method, which was developed into the Instantaneous Frequency of Spin Echo (IFSE and the Instantaneous Frequency of Spin Echo Series (IFSES methods. The above named methods are described in this paper and their a comparison is also presented.

  12. Measurement of myocardial perfusion using magnetic resonance

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Jensen, L.T.; Larsson, H.B.;

    2008-01-01

    Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper review...... myocardial perfusion imaging with MR contrast agents: methods, validation and experiences from clinical studies. Unresolved issues still restrict the use of these techniques to research although clinical applications are within reach Udgivelsesdato: 2008/12/8......Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper reviews...

  13. Measurement of myocardial perfusion using magnetic resonance

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Jensen, L.T.; Larsson, H.B.

    2008-01-01

    Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper reviews...... myocardial perfusion imaging with MR contrast agents: methods, validation and experiences from clinical studies. Unresolved issues still restrict the use of these techniques to research although clinical applications are within reach Udgivelsesdato: 2008/12/8...

  14. A Fast Digital Integrator for Magnetic Measurements

    CERN Document Server

    Spiezia, G

    2008-01-01

    In this work, the Fast Digitial Integrator (FDI), conceived for characterizing dynamic features of superconducting magnets and measuring fast transients of magnetic fields at the European Organization for Nuclear Research (CERN) and other high-energy physics research centres, is presented. FDI development was carried out inside a framework of cooperation between the group of Magnet Tests and Measurements of CERN and the Department of Engineering of the University of Sannio. Drawbacks related to measurement time decrease of main high-performance analog-to-digital architectures, such as Delta-Sigma and integrators, are overcome by founding the design on (i) a new generation of successive approximation converters, for high resolution (18-bit) at high rate (500 kS/s), (ii) a digital signal processor, for on-line down-sampling by integrating the input signal, (iii) a custom time base, based on a Universal Time Counter, for reducing time-domain uncertainty, and (iv) a PXI board, for high bus transfer rate, as well ...

  15. Measurement of magnetic properties at cryogenic temperatures

    CERN Multimedia

    1977-01-01

    This picture shows part of the low-mu permeameter to measure permeability of stainless steels and other low-mu materials used in superconducting magnets. The sample, a 5 mm diam., 45 mm long rod, is suspended to long leads before being inserted in the test cryostat. For the measurement the sample is surrounded by a flux- measuring coil and placed in the field of a superconducting solenoid. At a given field the sample is removed.During the removal, the voltage induced in the flux-measuring coil is time integrated giving the flux variation. This equipment was developed to select stainless steels and other low-mu materials used in the ISR Prototype Superconducting Qaudrupole. The person is W.Ansorge.

  16. Macroscopic superpositions and gravimetry with quantum magnetomechanics

    Science.gov (United States)

    Johnsson, Mattias T.; Brennen, Gavin K.; Twamley, Jason

    2016-11-01

    Precision measurements of gravity can provide tests of fundamental physics and are of broad practical interest for metrology. We propose a scheme for absolute gravimetry using a quantum magnetomechanical system consisting of a magnetically trapped superconducting resonator whose motion is controlled and measured by a nearby RF-SQUID or flux qubit. By driving the mechanical massive resonator to be in a macroscopic superposition of two different heights our we predict that our interferometry protocol could, subject to systematic errors, achieve a gravimetric sensitivity of Δg/g ~ 2.2 × 10-10 Hz-1/2, with a spatial resolution of a few nanometres. This sensitivity and spatial resolution exceeds the precision of current state of the art atom-interferometric and corner-cube gravimeters by more than an order of magnitude, and unlike classical superconducting interferometers produces an absolute rather than relative measurement of gravity. In addition, our scheme takes measurements at ~10 kHz, a region where the ambient vibrational noise spectrum is heavily suppressed compared the ~10 Hz region relevant for current cold atom gravimeters.

  17. A portable magnetic induction measurement system (PIMS).

    Science.gov (United States)

    Cordes, Axel; Foussier, Jérôme; Pollig, Daniel; Leonhardt, Steffen

    2012-02-22

    For contactless monitoring of ventilation and heart activity, magnetic induction measurements are applicable. As the technique is harmless for the human body, it is well suited for long-term monitoring solutions, e.g., bedside monitoring, monitoring of home care patients, and the monitoring of persons in critical occupations. For such settings, a two-channel portable magnetic induction system has been developed, which is small and light enough to be fitted in a chair or bed. Because demodulation, control, and filtering are implemented on a front-end digital signal processor, a PC is not required (except for visualization/data storage during research and development). The system can be connected to a local area network (LAN) or wireless network (WiFi), allowing to connect several devices to a large monitoring system, e.g., for a residential home for the elderly or a hospital with low-risk patients not requiring standard ECG monitoring. To visualize data streams, a Qt-based (Qt-framework by Nokia, Espoo, Finland) monitoring application has been developed, which runs on Netbook computers, laptops, or standard PCs. To induce and measure the magnetic fields, external coils and amplifiers are required. This article describes the system and presents results for monitoring respiration and heart activity in a (divan) bed and for respiration monitoring in a chair. Planar configurations and orthogonal coil setups were examined during the measurement procedures. The measurement data were streamed over a LAN to a monitoring PC running Matlab (The MathWorks Inc, Natick, MA, USA).

  18. Improved Reconstruction of Dipole Directions from Spherical Magnetic Field Measurements

    CERN Document Server

    Gerhards, Christian

    2016-01-01

    Reconstructing magnetizations from measurements of the generated magnetic potential is highly non-unique. The matter of uniqueness can be improved, but not entirely resolved, by the assumption that the magnetization is locally supported. Here, we focus on the case that the magnetization is additionally assumed to be induced by an ambient magnetic dipole field, i.e., the task is to reconstruct the dipole direction as well as the susceptibility of the magnetic material. We investigate uniqueness issues and provide a reconstruction procedure from given magnetic potential measurements on a spherical surface.

  19. Measuring the Earth's Magnetic Field in a Laboratory

    Science.gov (United States)

    Cartacci, A.; Straulino, S.

    2008-01-01

    Two methods for measuring the Earth's magnetic field are described. In the former, according to Gauss, the Earth's magnetic field is compared with that of a permanent magnet; in the latter, a well-known method, the comparison is made with the magnetic field generated by a current. As all the used instruments are available off the shelf, both…

  20. Observability of relative phases of macroscopic quantum states

    CERN Document Server

    Pati, A K

    1998-01-01

    After a measurement, to observe the relative phases of macroscopically distinguishable states we have to ``undo'' a quantum measurement. We generalise an earlier model of Peres from two state to N-state quantum system undergoing measurement process and discuss the issue of observing relative phases of different branches. We derive an inequality which is satisfied by the relative phases of macroscopically distinguishable states and consequently any desired relative phases can not be observed in interference setups. The principle of macroscopic complementarity is invoked that might be at ease with the macroscopic world. We illustrate the idea of limit on phase observability in Stern-Gerlach measurements and the implications are discussed.

  1. A modified Rogowski coil for measurements of hybrid permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Bertsche, K.

    1996-08-01

    For large permanent magnets, as proposed for the Fermilab Recycler Ring, it may be important to quickly verify that the magnet`s strength is correct. This may be important, for example, if a magnet is suspected of having changed due to some sort of accident. The field strength of a pure dipole can be readily measured with a Hall probe, but for indexed dipoles and for quadrupoles a Hall probe will not give very accurate results without precise positioning. We have investigated a different approach, the use of a modified Rogowski coil to measure the magnetic potential of each pole. As long as magnet geometry is fixed and known, measurement of the magnetic potential at each pole gives a good measurement of field strength even for magnets with large quadrupole components. The construction and use of such a coil and the precision of measurements made with it will be discussed. 4 refs., 5 figs.

  2. Magnetic Measurements of Storage Ring Magnets for the APS Upgrade Project

    Energy Technology Data Exchange (ETDEWEB)

    Doose, C.; Dejus, R.; Jaski, M.; Jansma, W.; Collins, J.; Donnelly, A.; Liu, J.; Cease, H.; Decker, G.; Jain, A.; DiMarco, J.

    2017-06-01

    Extensive prototyping of storage ring magnets is ongoing at the Advanced Photon Source (APS) in support of the APS Multi-Bend Achromat (MBA) upgrade project (APS-U) [1]. As part of the R&D activities four quadrupole magnets with slightly different geometries and pole tip materials, and one sextupole magnet with vanadium permendur (VP) pole tips were designed, built and tested. Magnets were measured individually using a rotating coil and a Hall probe for detailed mapping of the magnetic field. Magnets were then assembled and aligned relative to each other on a steel support plate and concrete plinth using precision machined surfaces to gain experience with the alignment method chosen for the APS-U storage ring magnets. The required alignment of magnets on a common support structure is 30 μm rms. Measurements of magnetic field quality, strength and magnet alignment after subjecting the magnets and assemblies to different tests are presented.

  3. Classifying, archiving and digitalizing documents related to normal conducting magnets & preparing graphs of magnetic measurement results

    CERN Document Server

    Bayramoglu, Gultug

    2016-01-01

    The main project aims to classify and digitalize documents related to normal conducting magnets. These documents include magnetic measurement results and their graphs, inspection reports, manufacturing reports and so on. The archive of Normal Conducting Magnets Section consists lots of different types of normal conducting magnets documents. Besides these magnet varieties, there are still documents from the times of first accelerator at CERN. In that moment, my project involves to identify, classify and digitalize documents and make them ready to be uploaded in NORMA - database of normal conducting magnets. In addition part of my time I’ve spent on second project, which was preparing graphs of magnetic measurement results of magnets such as current and magnetic field. The aim of these graphs is to compare parameters of magnets the same type and check measurement results’ consistency according to reference points. All of these graphs are on time basis.

  4. submitter Generalized Harmonic Analysis of Computed and Measured Magnetic Fields

    CERN Document Server

    Auchmann, B; Petrone, C; Russenschuck, S

    2016-01-01

    In this paper, we present a generalized approach for the harmonic analysis of the magnetic field in accelerator magnets. This analysis is based on the covariant components of the computed or measured magnetic flux density. The multipole coefficients obtained in this way can be used for magnet optimization and field reconstruction in the interior of circular and elliptical boundaries in the bore of straight magnets.

  5. PHASE GRADIENT METHOD OF MAGNETIC FIELD MEASUREMENTS IN ELECTRIC VEHICLES

    Directory of Open Access Journals (Sweden)

    N. G. Ptitsyna

    2013-01-01

    Full Text Available Operation of electric and hybrid vehicles demands real time magnetic field control, for instance, for fire and electromagnetic safety. The article deals with a method of magnetic field measurements onboard electric cars taking into account peculiar features of these fields. The method is based on differential methods of measurements, and minimizes the quantity of magnetic sensors.

  6. Macroscopic spin and charge transport theory

    Institute of Scientific and Technical Information of China (English)

    Li Da-Fang; Shi Jun-Ren

    2009-01-01

    According to the general principle of non-equilibrium thermodynamics, we propose a set of macroscopic transport equations for the spin transport and the charge transport. In particular, the spin torque is introduced as a generalized 'current density' to describe the phenomena associated with the spin non-conservation in a unified framework. The Einstein relations and the Onsager relations between different transport phenomena are established. Specifically, the spin transport properties of the isotropic non-magnetic and the isotropic magnetic two-dimensional electron gases are fully described by using this theory, in which only the macroscopic-spin-related transport phenomena allowed by the symmetry of the system are taken into account.

  7. Modified methods of stellar magnetic field measurements

    CERN Document Server

    Kholtygin, A F

    2013-01-01

    The standard methods of the magnetic field measurement, based on an analysis of the relation between the Stokes $V$-parameter and the first derivative of the total line profile intensity, were modified by applying a linear integral operator $\\hat{L}$ to the both sides of this relation. As the operator $\\hat{L}$, the operator of the wavelet transform with DOG-wavelets is used. The key advantage of the proposed method is an effective suppression of the noise contribution to the line profile and the Stokes parameter $V$. The efficiency of the method has been studied using the model line profiles with various noise contributions. To test the proposed method, the spectropolarimetric observations of the A0-type star $\\alpha^2\\,$ CVn, young O-type star $\\theta^1$ Ori C and A0 supergiant HD 92207 were used. The longitudinal magnetic field strengths for these stars calculated by our method appeared to be in a good agreement with those determined by other methods.

  8. Measuring the Magnetic Force on a Current-Carrying Conductor.

    Science.gov (United States)

    Herreman, W.; Huysentruyt, R.

    1995-01-01

    Describes a fast and simple method for measuring the magnetic force acting on a current-carrying conductor using a digital balance. Discusses the influence of current intensity and wire length on the magnetic force on the conductor. (JRH)

  9. Ultrathin magnetic structures II measurement techniques and novel magnetic properties

    CERN Document Server

    Heinrich, Bretislav

    2006-01-01

    The ability to understand and control the unique properties of interfaces has created an entirely new field of magnetism, with profound impact in technology and serving as the basis for a revolution in electronics. Our understanding of the physics of magnetic nanostructures has also advanced significantly. This rapid development has generated a need for a comprehensive treatment that can serve as an introduction to the field for those entering it from diverse fields, but which will also serve as a timely overview for those already working in this area. The four-volume work Ultra-Thin Magnetic

  10. Covariant Macroscopic Quantum Geometry

    CERN Document Server

    Hogan, Craig J

    2012-01-01

    A covariant noncommutative algebra of position operators is presented, and interpreted as the macroscopic limit of a geometry that describes a collective quantum behavior of the positions of massive bodies in a flat emergent space-time. The commutator defines a quantum-geometrical relationship between world lines that depends on their separation and relative velocity, but on no other property of the bodies, and leads to a transverse uncertainty of the geometrical wave function that increases with separation. The number of geometrical degrees of freedom in a space-time volume scales holographically, as the surface area in Planck units. Ongoing branching of the wave function causes fluctuations in transverse position, shared coherently among bodies with similar trajectories. The theory can be tested using appropriately configured Michelson interferometers.

  11. Field quality measurements of a 2-Tesla transmission line magnet

    Energy Technology Data Exchange (ETDEWEB)

    Velev, G.V.; Foster, W.; Kashikhin, V.; Mazur, P.; Oleck, A.; Piekarz, H.; Schlabach, P.; Sylvester, C.; /Fermilab; Wake, M.; /KEK, Tsukuba

    2005-09-01

    A prototype 2-Tesla superconducting transmission line magnet for future hadron colliders was designed, built and tested at Fermilab. The 1.5 m long, combined-function gradient-dipole magnet has a vertical pole aperture of 20 mm. To measure the magnetic field quality in such a small magnet aperture, a specialized rotating coil of 15.2 mm diameter, 0.69 m long was fabricated. Using this probe, a program of magnetic field quality measurements was successfully performed. Results of the measurements are presented and discussed.

  12. Microscopic Faraday rotation measurement system using pulsed magnetic fields.

    Science.gov (United States)

    Egami, Shigeki; Watarai, Hitoshi

    2009-09-01

    Microscopic Faraday rotation measurement system using a pulsed magnetic field has been constructed, which can be applied to micron sized diamagnetic and paramagnetic materials. A pulsed magnetic coil could generate a maximum magnetic flux density of about 12 T. The performance of the microscopic Faraday rotation apparatus was demonstrated by the measurement of the Verdet constant V of a polystyrene particle, after the calibration of the pulsed magnetic flux density using a glass plate as a standard material. Also, the magneto-optical rotation dispersion of some diamagnetic substances have been measured and analyzed with V=alambda(-2)+b. The values of a and b were compared to their magnetic susceptibilities.

  13. Anisotropic magnetothermopower in ferromagnetic thin films grown on macroscopic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Jayathilaka, P.B. [Department of Physical Sciences, Faculty of Applied Sciences, Rajarata University of Sri Lanka, Mihintale (Sri Lanka); Belyea, D.D. [Department of Physics, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620 (United States); Fawcett, T.J. [College of Engineering, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620 (United States); Miller, Casey W. [School of Chemistry and Materials Science, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2015-05-15

    We report observing the anisotropic magnetothermopower in a variety of ferromagnetic thin films grown on macroscopic substrates. These measurements were enabled by eliminating spurious signals related to the Anomalous Nernst Effect by butt-mounting the sample to the heat source and sink, and appropriate positioning of electrical contacts to avoid unwanted thermal gradients. This protocol enabled detailed measurements of the magnetothermopower in the transverse and longitudinal configurations. This may enable Spin Seebeck Effect studies in the in-plane geometry. - Highlights: • Unintentional thermal gradients along surface normal mitigated via butt-mounting. • Longitudinal/transverse magnetothermopower measured on many systems. • Anomalous Nernst Effect reduced. • Importance of magnetic anisotropy identified with angle-dependent measurements.

  14. Physics and measurements of magnetic materials

    CERN Document Server

    Sgobba, S

    2010-01-01

    Magnetic materials, both hard and soft, are used extensively in several components of particle accelerators. Magnetically soft iron-nickel alloys are used as shields for the vacuum chambers of accelerator injection and extraction septa; Fe-based material is widely employed for cores of accelerator and experiment magnets; soft spinel ferrites are used in collimators to damp trapped modes; innovative materials such as amorphous or nanocrystalline core materials are envisaged in transformers for high-frequency polyphase resonant convertors for application to the International Linear Collider (ILC). In the field of fusion, for induction cores of the linac of heavy-ion inertial fusion energy accelerators, based on induction accelerators requiring some 107 kg of magnetic materials, nanocrystalline materials would show the best performance in terms of core losses for magnetization rates as high as 105 T/s to 107 T/s. After a review of the magnetic properties of materials and the different types of magnetic behaviour...

  15. Canonical quantization of macroscopic electromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Philbin, T G, E-mail: tgp3@st-andrews.ac.u [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom)

    2010-12-15

    Application of the standard canonical quantization rules of quantum field theory to macroscopic electromagnetism has encountered obstacles due to material dispersion and absorption. This has led to a phenomenological approach to macroscopic quantum electrodynamics where no canonical formulation is attempted. In this paper macroscopic electromagnetism is canonically quantized. The results apply to any linear, inhomogeneous, magnetodielectric medium with dielectric functions that obey the Kramers-Kronig relations. The prescriptions of the phenomenological approach are derived from the canonical theory.

  16. Canonical quantization of macroscopic electromagnetism

    CERN Document Server

    Philbin, T G

    2010-01-01

    Application of the standard canonical quantization rules of quantum field theory to macroscopic electromagnetism has encountered obstacles due to material dispersion and absorption. This has led to a phenomenological approach to macroscopic quantum electrodynamics where no canonical formulation is attempted. In this paper macroscopic electromagnetism is canonically quantized. The results apply to any linear, inhomogeneous, magnetoelectric medium with dielectric functions that obey the Kramers-Kronig relations. The prescriptions of the phenomenological approach are derived from the canonical theory.

  17. Requirements for the Construction of the LCLS Magnetic Measurements Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, Z.

    2005-01-31

    The LCLS will require very demanding magnetic measurements. At present, SLAC does not have a magnetic measurements laboratory capable of performing the LCLS measurements. Therefore, a new magnetic measurement facility will be built at SLAC. Final tuning of the undulators and all .ducializations will be done right before installation. Having the facility at SLAC also allows rapid checks of any components which are not operating properly. In addition, periodic checks of components can be made to look for ageing. This note gives specifications for constructing the new laboratory so that all magnetic measurement accuracy requirements can be met.

  18. Searching for the nanoscopic–macroscopic boundary

    Energy Technology Data Exchange (ETDEWEB)

    Velásquez, E.A. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Grupo de Investigación en Modelamiento y Simulación Computacional, Universidad de San Buenaventura Sec. Medellín, A.A. 5222, Medellín (Colombia); Altbir, D. [Departamento de Física, Universidad de Santiago de Chile (USACH), CEDENNA, Santiago (Chile); Mazo-Zuluaga, J. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Duque, L.F. [GICM and GES Groups, Instituto de Física-FCEN, Universidad de Antioquia UdeA, Calle 70 No. 52-21 Medellín (Colombia); Grupo de Física Teórica, Aplicada y Didáctica, Facultad de Ciencias Exactas y Aplicadas Instituto Tecnológico Metropolitano, Medellín (Colombia); Mejía-López, J., E-mail: jmejia@puc.cl [Facultad de Física, Pontificia Universidad Católica de Chile, CEDENNA, Santiago (Chile)

    2013-12-15

    Several studies have focused on the size-dependent properties of elements, looking for a unique definition of the nanoscopic–macroscopic boundary. By using a novel approach consisting of an energy variational method combined with a quantum Heisenberg model, here we address the size at which the ordering temperature of a magnetic nanoparticle reaches its bulk value. We consider samples with sizes in the range 1–500 nm, as well as several geometries and crystalline lattices and observe that, contrarily to what is commonly argued, the nanoscopic-microscopic boundary depends on both factors: shape and crystalline structure. This suggests that the surface-to-volume ratio is not the unique parameter that defines the behavior of a nanometric sample whenever its size increases reaching the bulk dimension. Comparisons reveal very good agreement with experimental evidence with differences less than 2%. Our results have broad implications for practical issues in measurements on systems at the nanometric scale. - Highlights: • A novel quantum-Heisenberg variational energy method is implemented. • The asymptotic behavior toward the thermodynamic limit is explored. • An important dependence of the nano-bulk boundary on the geometry is found. • And also an important dependence on the crystalline lattice. • We obtain a very good agreement with experimental evidence with differences <2%.

  19. System for controllable magnetic measurement with direct field determination

    Science.gov (United States)

    Stupakov, O.

    2012-02-01

    This work describes a specially designed setup for magnetic hysteresis and Barkhausen noise measurements. The setup combines two main elements: an improved fast algorithm to control the waveform of magnetic induction and simultaneous direct determination of the magnetic field. The digital feedback algorithm uses only the previous measurement cycle to correct the magnetization voltage without any additional correlation parameter; it usually converges after several tens of cycles. The magnetic field is measured at the sample surface using a vertically mounted array of sensitive Hall sensors. Linear extrapolation of the tangential field profile to the sample surface determines the true waveform of the magnetic field. This unique combination of physically based control for both parameters of the magnetization process provides stable and reliable results, which are independent of a specified experimental configuration. This is illustrated for the industrially attractive measurements of non-oriented electrical steels with a 50 Hz sinusoidal induction waveform.

  20. Permanent magnets including undulators and wigglers

    OpenAIRE

    Bahrdt, J.

    2011-01-01

    After a few historic remarks on magnetic materials we introduce the basic definitions related to permanent magnets. The magnetic properties of the most common materials are reviewed and the production processes are described. Measurement techniques for the characterization of macroscopic and microscopic properties of permanent magnets are presented. Field simulation techniques for permanent magnet devices are discussed. Today, permanent magnets are used in many fields. This article concentrat...

  1. Measurement of the magnetic field-dependent refractive index of magnetic fluids in bulk

    Institute of Scientific and Technical Information of China (English)

    Ting Liu; Xianfeng Chen; Ziyun Di; Junfeng Zhang; Xinwan Li; Jianping Chen

    2008-01-01

    An optical alignment-free and highly accurate method is employed to measure the magnetic field-dependent refractive index of magnetic fluid(MF) in bulk.The measured refractive index decreases significantly with the increasing magnetic strength and then tends to saturate in the high intensity range.By applying a tunable magnetic field ranging between 0 and 1661 Oe,the maximum shift of the refractive index of MF in bulk iS found to be 0.0231.

  2. Measurement of the magnetic-field parameters of the NICA Booster dipole magnet

    Science.gov (United States)

    Kostromin, S. A.; Borisov, V. V.; Bichkov, A. V.; Golubitsky, O. M.; Donyagin, A. N.; Morozov, N. A.; Samsonov, E. V.; Omelyanenko, M. M.; Khodzhibagiyan, H. G.; Shemchuk, A. V.

    2016-12-01

    Serial assembly and tests of dipole and quadrupole magnets of the NICA Booster have started at the Laboratory of High Energy Physics of the Joint Institute for Nuclear Research (JINR). The accelerator is fitted with Nuclotron-type magnets with a superconducting winding and an iron yoke for shaping the needed magnetic field. The design of magnets for NICA was optimized (based on the experience gained in constructing and operating the JINR Nuclotron) for the production of magnetic fields of the required configuration in terms of the beam dynamics in the accelerator and the collider. Measurements of parameters of the field of each magnet are expected to be performed in the process of assembly and testing of each module of the magnet-cryostat system of the NICA Booster and Collider. The results of magnetic measurements for the NICA Booster dipole magnet are presented.

  3. A macroscopic challenge for quantum spacetime

    CERN Document Server

    Amelino-Camelia, Giovanni

    2013-01-01

    Over the last decade a growing number of quantum-gravity researchers has been looking for opportunities for the first ever experimental evidence of a Planck-length quantum property of spacetime. These studies are usually based on the analysis of some candidate indirect implications of spacetime quantization, such as a possible curvature of momentum space. Some recent proposals have raised hope that we might also gain direct experimental access to quantum properties of spacetime, by finding evidence of limitations to the measurability of the center-of-mass coordinates of some macroscopic bodies. However I here observe that the arguments that originally lead to speculating about spacetime quantization do not apply to the localization of the center of mass of a macroscopic body. And I also analyze some popular formalizations of the notion of quantum spacetime, finding that when the quantization of spacetime is Planckian for the constituent particles then for the composite macroscopic body the quantization of spa...

  4. On Macroscopic Complexity and Perceptual Coding

    CERN Document Server

    Scoville, John

    2010-01-01

    While Shannon information establishes limits to the universal data compression of binary data, no existing theory provides an equivalent characterization of the lossy data compression algorithms prevalent in audiovisual media. The current paper proposes a mathematical framework for perceptual coding and inference which quantifies the complexity of objects indistinguishable to a particular observer. A definition of the complexity is presented and related to a generalization of Boltzmann entropy for these equivalence classes. When the classes are partitions of phase space, corresponding to classical observations, this is the proper Boltzmann entropy and the macroscopic complexity agrees with the Algorithmic Entropy. For general classes, the macroscopic complexity measure determines the optimal lossy compression of the data. Conversely, perceptual coding algorithms may be used to construct upper bounds on certain macroscopic complexities. Knowledge of these complexities, in turn, allows perceptual inference whic...

  5. Zero-Field Magnetism of a Two-Dimensional Antiferromagnet, κ-(BEDT-TTF)2Cu[N(CN)2]Cl, Determined by Muon Spin Rotation and Magnetization Measurements

    Science.gov (United States)

    Ito, Miho; Uehara, Tomotaka; Taniguchi, Hiromi; Satoh, Kazuhiko; Ishii, Yasuyuki; Watanabe, Isao

    2015-05-01

    The zero-field magnetism of a two-dimensional noncollinear antiferromagnet, κ-(BEDT-TTF)2Cu[N(CN)2]Cl, has been investigated by magnetization and zero-field muon spin rotation (μSR) measurements. Low-field magnetization measurements enabled us to determine the magnetic transition temperature TN as 22.80 ± 0.02 K. Distinct muon spin precession signals appeared below 21.4 K. μSR spectra below 21.4 K were well described by two types of precession components and a relaxation one. The temperature dependence of internal field converted by μSR data was in good agreement with that of macroscopic residual magnetism. These results suggest that the tiny interlayer interaction, which has been suggested to be almost 106 times less than the intralayer exchange interaction, spontaneously causes the three-dimensional long-range order.

  6. Electrical, Magnetic, and Optical Measurement Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides tools necessary for electrical, magnetic, and optical characterization of bulk and thin-film materials. This includes the ability to determine the...

  7. Nanosecond-resolved temperature measurements using magnetic nanoparticles

    Science.gov (United States)

    Xu, Wenbiao; Liu, Wenzhong; Zhang, Pu

    2016-05-01

    Instantaneous and noninvasive temperature measurements are important when laser thermotherapy or welding is performed. A noninvasive nanosecond-resolved magnetic nanoparticle (MNP) temperature measurement system is described in which a transient change in temperature causes an instantaneous change in the magnetic susceptibilities of the MNPs. These transient changes in the magnetic susceptibilities are rapidly recorded using a wideband magnetic measurement system with an upper frequency limit of 0.5 GHz. The Langevin function (the thermodynamic model characterizing the MNP magnetization process) is used to obtain the temperature information. Experiments showed that the MNP DC magnetization temperature-measurement system can detect a 14.4 ns laser pulse at least. This method of measuring temperature is likely to be useful for acquiring the internal temperatures of materials irradiated with lasers, as well as in other areas of research.

  8. Measurement of the ATLAS solenoid magnetic field

    CERN Document Server

    Aleksa, M; Giudici, P-A; Kehrli, A; Losasso, M; Pons, X; Sandaker, H; Miyagawa, P S; Snow, S W; Hart, J C; Chevalier, L

    2008-01-01

    ATLAS is a general purpose detector designed to explore a wide range of physics at the Large Hadron Collider. At the centre of ATLAS is a tracking detector in a 2 T solenoidal magnetic field. This paper describes the machine built to map the field, the data analysis methods, the final results, and their estimated uncertainties. The remotely controlled mapping machine used pneumatic motors with feedback from optical encoders to scan an array of Hall probes over the field volume and log data at more than 20 000 points in a few hours. The data were analysed, making full use of the physical constraints on the field and of our knowledge of the solenoid coil geometry. After a series of small corrections derived from the data itself, the resulting maps were fitted with a function obeying Maxwell's equations. The fit residuals had an r.m.s. less than 0.5 mT and the systematic error on the measurement of track sagitta due to the field uncertainty was estimated to be in the range 0.02 % to 0.12 % depending on the track...

  9. Assessing magnetic nanoparticle aggregation in polymer melts by dynamic magnetic susceptibility measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sierra-Bermúdez, Sergio [Department of Chemical Engineering, University of Puerto Rico, P.O. Box 9000 Mayaguez, PR 00681 PR (United States); Maldonado-Camargo, Lorena P. [Department of Chemical Engineering, University of Florida, 1006 Center Drive, Gainesville, FL 32603 (United States); Orange, François [Department of Physics and Nanoscopy Facility, College of Natural Sciences, University of Puerto Rico, PO Box 70377, San Juan, PR 00936-8377 (United States); Guinel, Maxime J.-F. [Department of Physics and Nanoscopy Facility, College of Natural Sciences, University of Puerto Rico, PO Box 70377, San Juan, PR 00936-8377 (United States); Department of Chemistry, College of Natural Sciences, University of Puerto Rico, PO Box 70377, San Juan, PR 00936-8377 (United States); Rinaldi, Carlos, E-mail: carlos.rinaldi@bme.ufl.edu [J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, PO Box 116131, Gainesville, FL 32611-6131 (United States)

    2015-03-15

    Aggregation of magnetic nanoparticles in polymer melts was assessed using dynamic magnetic susceptibility measurements. Magnetic nanocomposites consisting of polybutadiene/CoFe{sub 2}O{sub 4} and polystyrene/CoFe{sub 2}O{sub 4} mixtures were prepared using different techniques and characterized using dynamic magnetic susceptibility measurements. The presence of nanoparticle aggregates determined using magnetic measurements was confirmed with transmission electron microscopy examinations. The results were in good agreement with predictions from the Flory–Huggins interaction parameters. - Highlights: • Oleic acid coated magnetic nanoparticles (MNPs) were dispersed in polymer melts. • MNPs dispersed well in polybutadiene but not in polystyrene. • Dynamic magnetic susceptibility (DMS) measurements assessed presence of aggregates. • DMS predictions were confirmed by transmission electron microscopy. • The Flory-Huggins interaction parameter correlated with MNP dispersion.

  10. Rotational dynamics of magnetic silica spheres studied by measuring the complex magnetic susceptibility

    NARCIS (Netherlands)

    Claesson, E.M.; Erne, B.H.; Philipse, A.P.

    2007-01-01

    The weak permanent magnetic dipole moment of cobalt ferrite-doped colloidal silica spheres was increased by exposure to a saturating magnetic field. The resulting change of the rotational dynamics of the magnetic microspheres in a weak alternating field was measured from low to high volume fraction

  11. Magnetic susceptibility and magnetic resonance measurements of the moisture content and hydration condition of a magnetic mixture material

    Science.gov (United States)

    Tsukada, K.; Kusaka, T.; Saari, M. M.; Takagi, R.; Sakai, K.; Kiwa, T.; Bito, Y.

    2014-05-01

    We developed a magnetic measurement method to measure the moisture content and hydration condition of mortar as a magnetic mixture material. Mortar is a mixture of Portland cement, sand, and water, and these materials exhibit different magnetic properties. The magnetization-magnetic field curves of these components and of mortars with different moisture contents were measured, using a specially developed high-temperature-superconductor superconducting quantum interference device. Using the differences in magnetic characteristics, the moisture content of mortar was measured at the ferromagnetic saturation region over 250 mT. A correlation between magnetic susceptibility and moisture content was successfully established. After Portland cement and water are mixed, hydration begins. At the early stage of the hydration/gel, magnetization strength increased over time. To investigate the magnetization change, we measured the distribution between bound and free water in the mortar in the early stage by magnetic resonance imaging (MRI). The MRI results suggest that the amount of free water in mortar correlates with the change in magnetic susceptibility.

  12. Optical fibre bragg gratings based magnetic force measurement of magnetic bearings

    Science.gov (United States)

    Ding, Guoping; Zhou, Zude; Hu, Yefa; Zhou, Jianhua

    2008-12-01

    Magnetic bearings are typical electromechanical systems of high performance. Current-displacement-force relationship between stator and rotor is an important research topic of magnetic bearings. The critical issue is to realize magnetic force online dynamic measurement. This paper presents a novel method on magnetic force measurement of magnetic bearings with optical fibre bragg gratings (FBG), which realizes a non-contact and online force measurement with simple configuration, good noise immunity even when the rotor is running. A novel micro force transducer is designed and fabricated, which is mounted within the stator magnetic pole. To obtain current-displacement-force relationship a FBG based magnetic force measurement test rig is setup to simulate magnetic bearing working states as the stator coils currents, air gap between stator and rotor, rotor speed is adjustable. Magnetic force is measured under three classifications of test conditions and test results are presented. The measurement data show good consistency with the theory analysis and calculation, which means that the FBG based magnetic force measurement is available and of good accuracy.

  13. Characterization of the magnetic micro- and nanostructure in unalloyed steels by magnetic force microscopy

    Science.gov (United States)

    Batista, L.; Rabe, U.; Hirsekorn, S.

    2013-01-01

    The formation of a cementite phase influences significantly the macroscopic mechanical and magnetic properties of steels. Based on a correlation between mechanical and magnetic properties, mechanical properties as well as the morphology and content of the cementite phase can be inspected by electromagnetic non-destructive testing methods. The influence of the carbon content on bulk magnetic properties of unalloyed steels is studied on a macroscopic scale by hysteresis loop and Barkhausen noise measurements. The micro- and nanostructure is investigated by atomic force microscopy and magnetic force microscopy. Surface topography images and magnetic images of globular cementite precipitates embedded in a ferrite matrix are presented. The size, shape, and orientation of the precipitates influence the domain configuration. Applied external magnetic fields cause magnetization processes mainly in the ferrite matrix: Bloch walls move and are pinned by the cementite precipitates. The correlation between the microscopic observations and macroscopic magnetic properties of the material is discussed.

  14. Method and apparatus for measuring weak magnetic fields

    DEFF Research Database (Denmark)

    1995-01-01

    When measuring weak magnetic fields, a container containing a medium, such as a solution containing a stable radical, is placed in a polarising magnetic field, which is essentially at right angles to the field to be measured. The polarising field is interrupted rapidly, the interruption being...

  15. Very simple torque magnetometer for measuring magnetic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tejedor, M.; Fernandez, A.; Hernando, B.; Carrizo, J.

    1985-11-01

    A new torque magnetometer has been developed and built in order to measure magnetization saturation and perpendicular anisotropy of magnetic thin films. Its main characteristic is that it employs for counteraction the torque exerted on the sample in the same field used for exciting it. This gives rise to a great simplicity and sensitivity of the measuring system.

  16. Effect of permanent-magnet irregularities in levitation force measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Hull, J. R.

    1999-10-14

    In the measurement of the levitation force between a vertically magnetized permanent magnet (PM) and a bulk high-temperature superconductor (HTS), PM domains with horizontal components of magnetization are shown to produce a nonnegligible contribution to the levitation force in most systems. Such domains are typically found in all PMs, even in those that exhibit zero net horizontal magnetic moment. Extension of this analysis leads to an HTS analog of Earnshaw's theorem, in which at the field-cooling position the vertical stiffness is equal to the sum of the horizontal stiffnesses, independent of angular distribution of magnetic moments within the PM.

  17. Effect of permanent-magnet irregularities in levitation force measurements

    Science.gov (United States)

    Hull, John R.

    2000-06-01

    In the measurement of the levitation force between a vertically magnetized permanent magnet (PM) and a bulk high-temperature superconductor (HTS), PM domains with horizontal components of magnetization are shown to produce a non-negligible contribution to the levitation force in most systems. Such domains are typically found in all PMs, even in those that exhibit zero net horizontal magnetic moment. Extension of this analysis leads to an HTS analogue of Earnshaw's theorem, in which the vertical stiffness is equal to the sum of the horizontal stiffness at the field-cooling position, independent of the angular distribution of magnetic moments within the PM.

  18. Effect of permanent-magnet irregularities in levitation force measurements

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. [Energy Technology Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2000-06-01

    In the measurement of the levitation force between a vertically magnetized permanent magnet (PM) and a bulk high-temperature superconductor (HTS), PM domains with horizontal components of magnetization are shown to produce a non-negligible contribution to the levitation force in most systems. Such domains are typically found in all PMs, even in those that exhibit zero net horizontal magnetic moment. Extension of this analysis leads to an HTS analogue of Earnshaw's theorem, in which the vertical stiffness is equal to the sum of the horizontal stiffness at the field-cooling position, independent of the angular distribution of magnetic moments within the PM. (author)

  19. Lozenge Tilings, Glauber Dynamics and Macroscopic Shape

    Science.gov (United States)

    Laslier, Benoît; Toninelli, Fabio Lucio

    2015-09-01

    We study the Glauber dynamics on the set of tilings of a finite domain of the plane with lozenges of side 1/ L. Under the invariant measure of the process (the uniform measure over all tilings), it is well known (Cohn et al. J Am Math Soc 14:297-346, 2001) that the random height function associated to the tiling converges in probability, in the scaling limit , to a non-trivial macroscopic shape minimizing a certain surface tension functional. According to the boundary conditions, the macroscopic shape can be either analytic or contain "frozen regions" (Arctic Circle phenomenon Cohn et al. N Y J Math 4:137-165, 1998; Jockusch et al. Random domino tilings and the arctic circle theorem, arXiv:math/9801068, 1998). It is widely conjectured, on the basis of theoretical considerations (Henley J Statist Phys 89:483-507, 1997; Spohn J Stat Phys 71:1081-1132, 1993), partial mathematical results (Caputo et al. Commun Math Phys 311:157-189, 2012; Wilson Ann Appl Probab 14:274-325, 2004) and numerical simulations for similar models (Destainville Phys Rev Lett 88:030601, 2002; cf. also the bibliography in Henley (J Statist Phys 89:483-507, 1997) and Wilson (Ann Appl Probab 14:274-325, 2004), that the Glauber dynamics approaches the equilibrium macroscopic shape in a time of order L 2+ o(1). In this work we prove this conjecture, under the assumption that the macroscopic equilibrium shape contains no "frozen region".

  20. Magnetic susceptibility and magnetic resonance measurements of the moisture content and hydration condition of a magnetic mixture material

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, K., E-mail: tsukada@cc.okayama-u.ac.jp; Kusaka, T.; Saari, M. M.; Takagi, R.; Sakai, K.; Kiwa, T. [The Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530 (Japan); Bito, Y. [Central Research Lab., Hitachi. Ltd., 1-280 Higashi-Koigakubo, Kokubunji, Tokyo 185-8601 (Japan)

    2014-05-07

    We developed a magnetic measurement method to measure the moisture content and hydration condition of mortar as a magnetic mixture material. Mortar is a mixture of Portland cement, sand, and water, and these materials exhibit different magnetic properties. The magnetization–magnetic field curves of these components and of mortars with different moisture contents were measured, using a specially developed high-temperature-superconductor superconducting quantum interference device. Using the differences in magnetic characteristics, the moisture content of mortar was measured at the ferromagnetic saturation region over 250 mT. A correlation between magnetic susceptibility and moisture content was successfully established. After Portland cement and water are mixed, hydration begins. At the early stage of the hydration/gel, magnetization strength increased over time. To investigate the magnetization change, we measured the distribution between bound and free water in the mortar in the early stage by magnetic resonance imaging (MRI). The MRI results suggest that the amount of free water in mortar correlates with the change in magnetic susceptibility.

  1. Magnetic properties measurement of soft magnetic composite material (SOMALOY 700) by using 3-D tester

    Science.gov (United States)

    Asari, Ashraf; Guo, Youguang; Zhu, Jianguo

    2017-08-01

    Core losses of rotating electrical machine can be predicted by identifying the magnetic properties of the magnetic material. The magnetic properties should be properly measured since there are some variations of vector flux density in the rotating machine. In this paper, the SOMALOY 700 material has been measured under x, y and z- axes flux density penetration by using the 3-D tester. The calibrated sensing coils are used in detecting the flux densities which have been generated by the Labview software. The measured sensing voltages are used in obtaining the magnetic properties of the sample such as magnetic flux density B, magnetic field strength H, hysteresis loop which can be used to calculate the total core loss of the sample. The results of the measurement are analyzed by using the Mathcad software before being compared to another material.

  2. MEASUREMENTS OF STELLAR MAGNETIC FIELDS USING AUTOCORRELATION OF SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Borra, E. F.; Deschatelets, D. [Département de physique, de génie physique et d’optique. Université Laval (Canada)

    2015-11-15

    We present a novel technique that uses the autocorrelation of the spectrum of a star to measure the line broadening caused by the modulus of its average surface magnetic field. The advantage of the autocorrelation comes from the fact that it can detect very small spectral line broadening effects because it averages over many spectral lines and therefore gives an average with a very high signal-to-noise ratio. We validate the technique with the spectra of known magnetic stars and obtain autocorrelation curves that are in full agreement with published magnetic curves obtained with Zeeman splitting. The autocorrelation also gives less noisy curves so that it can be used to obtain very accurate curves. We degrade the resolution of the spectra of these magnetic stars to lower spectral resolutions where the Zeeman splitting is undetectable. At these resolutions, the autocorrelation still gives good quality curves, thereby showing that it can be used to measure magnetic fields in spectra where the Zeeman splitting is significantly smaller than the width of the spectral line. This would therefore allow observing magnetic fields in very faint Ap stars with low-resolution spectrographs, thereby greatly increasing the number of known magnetic stars. It also demonstrates that the autocorrelation can measure magnetic fields in rapidly rotating stars as well as weak magnetic fields that give a Zeeman splitting smaller than the intrinsic width of the spectral lines. Finally, it shows that the autocorrelation can be used to find unknown magnetic stars in low-resolution spectroscopic surveys.

  3. Laboratory Measurements of Astrophysical Magnetic Fields

    Science.gov (United States)

    Murphy, C. D.; Miniati, F.; Edwards, M.; Mithen, J.; Bell, A. R.; Constantin, C.; Everson, E.; Schaeffer, D.; Niemann, C.; Ravasio, A.; Brambrink, E.; Benuzzi-Mounaix, A.; Koenig, M.; Gregory, C.; Woolsey, N.; Park, H.-S.; Remington, B.; Ryutov, D.; Bingham, R.; Gargate, L.; Spitkovsky, A.; Gregori, G.

    2010-11-01

    It has been proposed that high Mach number collisionless shocks propagating in an initially unmagnetized plasma play a major role in the magnetization of large scale structures in the Universe. A detailed study of the experimental configuration necessary to scale such environments down to laboratory dimensions will be presented. We will show initial results from preliminary experiments conducted at the Phoenix laser (UCLA) and the LULI laser (Ecole Polytechnique) where collisionless shocks are generated by the expansion of exploding foils driven by energetic laser beams. The time evolution of the magnetic field is probed with induction coils placed at 10 cm from the laser focus. We will discuss various mechanisms of magnetic field generation and compare them with the experimental results.

  4. Measuring vector magnetic fields in solar prominences

    CERN Document Server

    Suárez, D Orozco; Bueno, J Trujillo

    2012-01-01

    We present spectropolarimetric observations in the He I 1083.0 nm multiplet of a quiescent, hedgerow solar prominence. The data were taken with the Tenerife Infrared Polarimeter attached to the German Vacuum Tower Telescope at the Observatorio del Teide (Tenerife; Canary Islands; Spain). The observed He I circular and linear polarization signals are dominated by the Zeeman effect and by atomic level polarization and the Hanle effect, respectively. These observables are sensitive to the strength and orientation of the magnetic field vector at each spatial point of the field of view. We determine the magnetic field vector of the prominence by applying the HAZEL inversion code to the observed Stokes profiles. We briefly discuss the retrieved magnetic field vector configuration.

  5. Measurement of dynamic magnetization induced by a pulsed field: Proposal for a new rock magnetism method

    Science.gov (United States)

    Kodama, Kazuto

    2015-02-01

    This study proposes a new method for measuring transient magnetization of natural samples induced by a pulsed field with duration of 11 ms using a pulse magnetizer. An experimental system was constructed, consisting of a pair of differential sensing coils connected with a high-speed digital oscilloscope for data acquisition. The data were transferred to a computer to obtain an initial magnetization curve and a descending branch of a hysteresis loop in a rapidly changing positive field. This system was tested with synthetic samples (permalloy ribbon, aluminum plate, and nickel powder) as well as two volcanic rock samples. Results from the synthetic samples showed considerable differences from those measured by a quasi-static method using a vibrating sample magnetometer (VSM). These differences were principally due to the time-dependent magnetic properties or to electromagnetic effects, such as magnetic viscosity, eddy current loss, or magnetic relaxation. Results from the natural samples showed that the transient magnetization-field curves were largely comparable to the corresponding portions of the hysteresis loops. However, the relative magnetization (scaled to the saturation magnetization) at the end of a pulse was greater than that measured by a VSM. This discrepancy, together with the occurrence of rapid exponential decay after a pulse, indicates magnetic relaxations that could be interpreted in terms of domain wall displacement. These results suggest that with further developments, the proposed technique can become a useful tool for characterizing magnetic particles contained in a variety of natural materials.

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

    Science.gov (United States)

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

    1996-03-01

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

  7. Magnetic properties of cobalt microwires measured by piezoresistive cantilever magnetometry

    Directory of Open Access Journals (Sweden)

    Tosolini G.

    2014-09-01

    Full Text Available We present the magnetic characterization of cobalt wires grown by focused electron beam-induced deposition (FEBID and studied using static piezoresistive cantilever magnetometry. We have used previously developed high force sensitive submicron-thick silicon piezoresistive cantilevers. High quality polycrystalline cobalt microwires have been grown by FEBID onto the free end of the cantilevers using dual beam equipment. In the presence of an external magnetic field, the magnetic cobalt wires become magnetized, which leads to the magnetic field dependent static deflection of the cantilevers. We show that the piezoresistive signal from the cantilevers, corresponding to a maximum force of about 1 nN, can be measured as a function of the applied magnetic field with a good signal to noise ratio at room temperature. The results highlight the flexibility of the FEBID technique for the growth of magnetic structures on specific substrates, in this case piezoresistive cantilevers.

  8. Ocean tidal signals in observatory and satellite magnetic measurements

    DEFF Research Database (Denmark)

    Maus, S.; Kuvshinov, A.

    2004-01-01

    Ocean flow moves sea water through the Earth's magnetic field, inducing electric fields, currents and secondary magnetic fields. These motionally induced magnetic fields have a potential for the remote sensing of ocean flow variability. A first goal must be to gain a better understanding...... of magnetic field generation by tidal ocean flow. We predict the motionally induced magnetic fields for the six major tidal constituents and compare their amplitudes with the spectra of night time observatory and satellite magnetic measurements for the Indian Ocean. The magnetic variations at the solar S2, K1......, and P1 periods turn out to be dominated by unrelated external fields. In contrast, observed lunar M2 and N2 tidal signals are in fair agreement with predictions from motional induction. The lunar diurnal O1 signal, visible at some observatories, could be caused by ocean flow but disagrees in amplitude...

  9. Precision measurements of the SLC reference magnets

    Energy Technology Data Exchange (ETDEWEB)

    Watson, S.; Levi, M.; Nash, J.

    1989-03-01

    Two spectrometers, one on each extraction line of the SLC, have been installed to momentum analyse each SLC beam pulse and determine the electron and positron beam energies. A method of determining and monitoring the absolute magnetic field strength for these dipoles has been developed. A total error on the magnetic field integral of {delta}{integral}Bdl/{integral}Bdl = 1 {times} 10{sup {minus}4} has been achieved. The field integral can be monitored continuously during SLC beam operation using radiation hardened equipment. The laboratory field mapping techniques and the field monitoring methods are described. 6 refs., 4 figs., 5 tabs.

  10. Electron-scale measurements of magnetic reconnection in space.

    Science.gov (United States)

    Burch, J L; Torbert, R B; Phan, T D; Chen, L-J; Moore, T E; Ergun, R E; Eastwood, J P; Gershman, D J; Cassak, P A; Argall, M R; Wang, S; Hesse, M; Pollock, C J; Giles, B L; Nakamura, R; Mauk, B H; Fuselier, S A; Russell, C T; Strangeway, R J; Drake, J F; Shay, M A; Khotyaintsev, Yu V; Lindqvist, P-A; Marklund, G; Wilder, F D; Young, D T; Torkar, K; Goldstein, J; Dorelli, J C; Avanov, L A; Oka, M; Baker, D N; Jaynes, A N; Goodrich, K A; Cohen, I J; Turner, D L; Fennell, J F; Blake, J B; Clemmons, J; Goldman, M; Newman, D; Petrinec, S M; Trattner, K J; Lavraud, B; Reiff, P H; Baumjohann, W; Magnes, W; Steller, M; Lewis, W; Saito, Y; Coffey, V; Chandler, M

    2016-06-03

    Magnetic reconnection is a fundamental physical process in plasmas whereby stored magnetic energy is converted into heat and kinetic energy of charged particles. Reconnection occurs in many astrophysical plasma environments and in laboratory plasmas. Using measurements with very high time resolution, NASA's Magnetospheric Multiscale (MMS) mission has found direct evidence for electron demagnetization and acceleration at sites along the sunward boundary of Earth's magnetosphere where the interplanetary magnetic field reconnects with the terrestrial magnetic field. We have (i) observed the conversion of magnetic energy to particle energy; (ii) measured the electric field and current, which together cause the dissipation of magnetic energy; and (iii) identified the electron population that carries the current as a result of demagnetization and acceleration within the reconnection diffusion/dissipation region.

  11. PIV MEASUREMENTS FOR GAS FLOW UNDER GRADIENT MAGNETIC FIELDS

    Institute of Scientific and Technical Information of China (English)

    RUAN Xiaodong; WU Feng; F.YAMAMOTO

    2004-01-01

    Particle Image Velocimetry (PIV) techniques were developed to measure the convective N2-air flow under gradient magnetic fields. The velocity fields were calculated by the Minimum Quadratic Difference (MQD) algorithm and spurious vectors were eliminated by Delaunay Tessellation.The N2-air flow was measured as the magnetic flux density varying from 0 ~ 1.5 T. A strengthened vortex flow of air was observed under the condition that the magnetic field was applied, and the velocity of N2 jet rose with the increase of the magnetic density. The experimental results show that the magnetic force will induce a vortex flow and cause a convection flow of the air mixture when both gradients of the O2 concentration and the magnetic field intensity exist.

  12. Fifth generation lithospheric magnetic field model from CHAMP satellite measurements

    OpenAIRE

    Maus, S.; Hermann Lühr; Martin Rother; Hemant, K.; Balasis, G.; Patricia Ritter; Claudia Stolle

    2007-01-01

    Six years of low-orbit CHAMP satellite magnetic measurements have provided an exceptionally high-quality data resource for lithospheric magnetic field modeling and interpretation. Here we describe the fifth-generation satellite-only magnetic field model MF5. The model extends to spherical harmonic degree 100. As a result of careful data selection, extensive corrections, filtering, and line leveling, the model has low noise levels, even if evaluated at the Earth's surface. The model is particu...

  13. Proceedings of Pulsed Magnet Design and Measurement Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Shaftan, T.; Heese, R.; Ozaki,S.

    2010-01-19

    The goals of the Workshop are to assess the design of pulsed system at the NSLS-II and establish mitigation strategies for critical issues during development. The focus of the Workshop is on resolving questions related to the set-up of the pulsed magnet laboratory, on measuring the pulsed magnet's current waveforms and fields, and on achieving tight tolerances on the magnet's alignment and field quality.

  14. Measurement of the SC magnetic field

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

    The 3.5-metre-arm carrying 100 Hall plates used for the measurmeent of the SC magnetic field. The arm rotates in a horizontal plane, its positioning and the data read-out are controlled by an on-line computer.

  15. Therapeutic magnetic microcarriers characterization by measuring magnetophoretic attributes

    Science.gov (United States)

    Vidal Ibacache, Guillermo

    Micro/nano robots are considered a promising approach to conduct minimally invasive interventions. We have proposed to embed magnetic nanoparticles in therapeutic or diagnostic agents in order to magnetically control them. A modified clinical Magnetic Resonance Imaging (MRI) scanner is used to provide the driving force that allows these magnetically embedded microcarriers to navigate the vascular human network. By using specific Magnetic Resonance (MR) gradient sequences this method has been validated in previous research works. Magnetophoresis is the term used to describe the fact that a magnetic particle changes its trajectory under the influence of a magnetic force while being carried by a fluid flow. This movement depends on the particle's magnetic characteristics, the particle's geometric shape, the fluid flow's attributes and other factors. In our proposed method, magnetic microcarriers can be produced in several different ways, and so their response will differ to the same magnetic force and fluid flow conditions. The outcome of the therapeutic treatment using our method depends on the adequate selection of the therapeutic and/or diagnosis agents to be used. The selected therapeutic and/or diagnosis magnetic microcarrier also influences the selection of the MR gradient sequence that best fit for a given treatment. This master's thesis presents the design of a device intended to assess the magnetophoretic properties of magnetic therapeutic microcarriers and/or diagnostic agents. Such characterization is essential for determining the optimal sequences of magnetic gradients to deflect their trajectory through relatively complex vascular networks in order to reach a pre-defined target. A microfluidic device was fabricated to validate the design. Magnetophoretic velocities are measured and a simple tracking method is proposed. The preliminary experimental results indicate that, despite some limitations, the proposed technique has the potential to be appropriate

  16. Magnetic field measurements of JT-60SA CS model coil

    Energy Technology Data Exchange (ETDEWEB)

    Obana, Tetsuhiro, E-mail: obana.tetsuhiro@LHD.nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Takahata, Kazuya; Hamaguchi, Shinji; Chikaraishi, Hirotaka; Mito, Toshiyuki; Imagawa, Shinsaku [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Kizu, Kaname; Murakami, Haruyuki; Natsume, Kyohei; Yoshida, Kiyoshi [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)

    2015-01-15

    Highlights: • Magnetic fields of the JT-60SA CS model coil were measured. • While the coil current was held constant at 20 kA, magnetic fields varied slightly with several different long time constants. • We investigated coils consisting of CIC conductors and having long time constants. - Abstract: In a cold test of the JT-60SA CS model coil, which has a quad-pancake configuration consisting of a Nb{sub 3}Sn cable-in-conduit (CIC) conductor, magnetic fields were measured using Hall sensors. For a holding coil current of 20 kA, measured magnetic fields varied slightly with long time constants in the range 17–571 s, which was much longer than the time constant derived from a measurement using a short straight sample. To validate the measurements, the magnetic fields of the model coil were calculated using a computational model representing the positions of Nb{sub 3}Sn strands inside the CIC conductor. The calculated results were in good agreement with the measurements. Consequently, the validity of the magnetic field measurements was confirmed. Next, we investigated other coils consisting of CIC conductors and having long time constants. The only commonality among the coils was the use of CIC conductors. At present, there is no obvious way to prevent generation of such magnetic-field variations with long time constants.

  17. A Steel Wire Stress Measuring Sensor Based on the Static Magnetization by Permanent Magnets.

    Science.gov (United States)

    Deng, Dongge; Wu, Xinjun; Zuo, Su

    2016-10-06

    A new stress measuring sensor is proposed to evaluate the axial stress in steel wires. Without using excitation and induction coils, the sensor mainly consists of a static magnetization unit made of permanent magnets and a magnetic field measurement unit containing Hall element arrays. Firstly, the principle is illustrated in detail. Under the excitation of the magnetization unit, a spatially varying magnetized region in the steel wire is utilized as the measurement region. Radial and axial magnetic flux densities at different lift-offs in this region are measured by the measurement unit to calculate the differential permeability curve and magnetization curve. Feature parameters extracted from the curves are used to evaluate the axial stress. Secondly, the special stress sensor for Φ5 and Φ7 steel wires is developed accordingly. At last, the performance of the sensor is tested experimentally. Experimental results show that the sensor can measure the magnetization curve accurately with the error in the range of ±6%. Furthermore, the obtained differential permeability at working points 1200 A/m and 10000 A/m change almost linearly with the stress in steel wires, the goodness of linear fits are all higher than 0.987. Thus, the proposed steel wire stress measuring sensor is feasible.

  18. A Steel Wire Stress Measuring Sensor Based on the Static Magnetization by Permanent Magnets

    Directory of Open Access Journals (Sweden)

    Dongge Deng

    2016-10-01

    Full Text Available A new stress measuring sensor is proposed to evaluate the axial stress in steel wires. Without using excitation and induction coils, the sensor mainly consists of a static magnetization unit made of permanent magnets and a magnetic field measurement unit containing Hall element arrays. Firstly, the principle is illustrated in detail. Under the excitation of the magnetization unit, a spatially varying magnetized region in the steel wire is utilized as the measurement region. Radial and axial magnetic flux densities at different lift-offs in this region are measured by the measurement unit to calculate the differential permeability curve and magnetization curve. Feature parameters extracted from the curves are used to evaluate the axial stress. Secondly, the special stress sensor for Φ5 and Φ7 steel wires is developed accordingly. At last, the performance of the sensor is tested experimentally. Experimental results show that the sensor can measure the magnetization curve accurately with the error in the range of ±6%. Furthermore, the obtained differential permeability at working points 1200 A/m and 10000 A/m change almost linearly with the stress in steel wires, the goodness of linear fits are all higher than 0.987. Thus, the proposed steel wire stress measuring sensor is feasible.

  19. Measurement of dynamic magnetization induced by a pulsed field: Proposal for a new rock magnetism method

    Directory of Open Access Journals (Sweden)

    Kazuto eKodama

    2015-02-01

    Full Text Available This study proposes a new method for measuring transient magnetization of natural samples induced by a pulsed field with duration of 11 ms using a pulse magnetizer. An experimental system was constructed, consisting of a pair of differential sensing coils connected with a high-speed digital oscilloscope for data acquisition. The data were transferred to a computer to obtain an initial magnetization curve and a descending branch of a hysteresis loop in a rapidly changing positive field. This system was tested with synthetic samples (permalloy ribbon, aluminum plate, and nickel powder as well as two volcanic rock samples. Results from the synthetic samples showed considerable differences from those measured by a quasi-static method using a vibrating sample magnetometer (VSM. These differences were principally due to the time-dependent magnetic properties or to electromagnetic effects, such as magnetic viscosity, eddy current loss, or magnetic relaxation. Results from the natural samples showed that the transient magnetization–field curves were largely comparable to the corresponding portions of the hysteresis loops. However, the relative magnetization (scaled to the saturation magnetization at the end of a pulse was greater than that measured by a VSM. This discrepancy, together with the occurrence of rapid exponential decay after a pulse, indicates magnetic relaxations that could be interpreted in terms of domain wall displacement. These results suggest that with further developments, the proposed technique can become a useful tool for characterizing magnetic particles contained in a variety of natural materials.

  20. Terahertz Science and Technology of Macroscopically Aligned Carbon Nanotube Films

    Science.gov (United States)

    Kono, Junichiro

    One of the outstanding challenges in nanotechnology is how to assemble individual nano-objects into macroscopic architectures while preserving their extraordinary properties. For example, the one-dimensional character of electrons in individual carbon nanotubes leads to extremely anisotropic transport, optical, and magnetic phenomena, but their macroscopic manifestations have been limited. Here, we describe methods for preparing macroscopic films, sheets, and fibers of highly aligned carbon nanotubes and their applications to basic and applied terahertz studies. Sufficiently thick films act as ideal terahertz polarizers, and appropriately doped films operate as polarization-sensitive, flexible, powerless, and ultra-broadband detectors. Together with recently developed chirality enrichment methods, these developments will ultimately allow us to study dynamic conductivities of interacting one-dimensional electrons in macroscopic single crystals of single-chirality single-wall carbon nanotubes.

  1. Stochastic magnetic measurement model for relative position and orientation estimation

    NARCIS (Netherlands)

    Schepers, H.M.; Veltink, P.H.

    2010-01-01

    This study presents a stochastic magnetic measurement model that can be used to estimate relative position and orientation. The model predicts the magnetic field generated by a single source coil at the location of the sensor. The model was used in a fusion filter that predicts the change of positio

  2. Stochastic magnetic measurement model for relative position and orientation estimation

    NARCIS (Netherlands)

    Schepers, H. Martin; Veltink, Petrus H.

    2010-01-01

    This study presents a stochastic magnetic measurement model that can be used to estimate relative position and orientation. The model predicts the magnetic field generated by a single source coil at the location of the sensor. The model was used in a fusion filter that predicts the change of positio

  3. Characterisation of Dynabeads (R) by magnetization measurements and Mossbauer spectroscopy

    DEFF Research Database (Denmark)

    Fonnum, G.; Johansson, C.; Molteberg, A.;

    2005-01-01

    X-ray diffraction, SEM analysis, Mossbauer spectroscopy and magnetic measurements were used to characterize three different magnetic beads (Dynabeads((R))). Maghemite (gamma-Fe2O3) is the predominant crystalline phase. The nanoparticles were evenly spread in the beads, and the crystal sizes were...

  4. A precise measurement of the muon magnetic anomaly

    NARCIS (Netherlands)

    Jungmann, KP

    2003-01-01

    At the Brookhaven National Laboratory (BNL) a precision experiment of the muon magnetic anomaly a(mu) in a magnetic storage ring is on its way. Measurements carried out on positive muons in 1999 have resulted in a(mu+) = 11,659,202(14)(6) x 10(-10) (1.3 ppm). A difference between this value and the

  5. The application of control theory to magnetic measurement

    CERN Document Server

    Chen Ying; Sun De Min; Xue Mei Sheng; Yao Cheng Gui

    2002-01-01

    In order to improve the efficiency of measurement, the authors introduced the control theory to the magnetic measurement system in NSRL. The authors succeeded in building a closed loop system, and performed measurement on the fly. While keeping the same accuracy as before, the efficiency has been greatly improved. It can be concluded that feedback is an effective method to advance measure system

  6. Measurement of the nonmagnetic coating thickness of core-shell magnetic nanoparticles by controlled magnetization magnetic force microscopy

    Science.gov (United States)

    Angeloni, L.; Passeri, D.; Scaramuzzo, F. A.; Di Iorio, D.; Barteri, M.; Mantovani, D.; Rossi, M.

    2016-06-01

    Magnetic nanoparticles (MNPs) represent an interesting tool for several biomedical applications. In order to improve the dispersion stability, the biocompatibility and bio-functionality, MNPs need to be coated with non-magnetic films. The optimization of these systems requires the deep characterization not only of the magnetic core, but also of the coating features. Beside the chemical and physical properties of the coating, its thickness is another important property which can influence the size, the shape and the overall magnetic behavior of the NPs system. In this work we propose a possible method to measure the thickness of the non-magnetic coating of core-shell MNPs through the use of controlled magnetization-magnetic force microscopy (CM-MFM). A preliminary study on the applicability of the proposed method has been performed on Fe3O4 NPs coated with a Cu film.

  7. Advanced Active-Magnetic-Bearing Thrust-Measurement System

    Science.gov (United States)

    Imlach, Joseph; Kasarda, Mary; Blumber, Eric

    2008-01-01

    An advanced thrust-measurement system utilizes active magnetic bearings to both (1) levitate a floating frame in all six degrees of freedom and (2) measure the levitation forces between the floating frame and a grounded frame. This system was developed for original use in measuring the thrust exerted by a rocket engine mounted on the floating frame, but can just as well be used in other force-measurement applications. This system offers several advantages over prior thrust-measurement systems based on mechanical support by flexures and/or load cells: The system includes multiple active magnetic bearings for each degree of freedom, so that by selective use of one, some, or all of these bearings, it is possible to test a given article over a wide force range in the same fixture, eliminating the need to transfer the article to different test fixtures to obtain the benefit of full-scale accuracy of different force-measurement devices for different force ranges. Like other active magnetic bearings, the active magnetic bearings of this system include closed-loop control subsystems, through which the stiffness and damping characteristics of the magnetic bearings can be modified electronically. The design of the system minimizes or eliminates cross-axis force-measurement errors. The active magnetic bearings are configured to provide support against movement along all three orthogonal Cartesian axes, and such that the support along a given axis does not produce force along any other axis. Moreover, by eliminating the need for such mechanical connections as flexures used in prior thrust-measurement systems, magnetic levitation of the floating frame eliminates what would otherwise be major sources of cross-axis forces and the associated measurement errors. Overall, relative to prior mechanical-support thrust-measurement systems, this system offers greater versatility for adaptation to a variety of test conditions and requirements. The basic idea of most prior active-magnetic

  8. Magnetic Fluctuation Measurement in Sino United Spherical Tokamak Plasma

    Institute of Scientific and Technical Information of China (English)

    LIU Fei; WANG Wen-Hao; HE Ye-Xi; LIU Jun; TAN Yi; XIE Li-Feng; ZENG Long

    2007-01-01

    To investigate the magnetic fluctuations and for further transport study, the poloidal and radial magnetic field measurement is conducted on the Sino United Spherical Tokamak (SUNIST). Auto-power spectral density indicates that the magnetic fluctuation energy mainly concentrates in the frequency region lower than 10kHz. The magnetic field oscillations, which are characterized by harmonic frequencies of 40 kHz, are observed in the scrapeoff layer; by contrast, in the plasma core, the magnetic fluctuations are of Gaussian type. The time-frequency profiles show that the poloidal magnetic fluctuations are temporally intermittent. The autocorrelation calculation indicates that the fluctuations in decorrelation time vary between the core and the edge.

  9. 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.

  10. Quasi-static magnetic measurements to predict specific absorption rates in magnetic fluid hyperthermia experiments

    OpenAIRE

    Coral, DF; Zelis, PM; de Sousa, ME; Muraca, D.; Lassalle, V.; Nicolas, P.; Ferreira,ML.; van Raap, MBF

    2014-01-01

    In this work, the issue on whether dynamic magnetic properties of polydispersed magnetic colloids modeled using physical magnitudes derived from quasi-static magnetic measurement can be extrapolated to analyze specific absorption rate data acquired at high amplitudes and frequencies of excitation fields is addressed. To this end, we have analyzed two colloids of magnetite nanoparticles coated with oleic acid and chitosan in water displaying, under a radiofrequency field, high and low specific...

  11. Field Measurement for Superconducting Magnets of ADS Injector I

    CERN Document Server

    Yang, Xiangchen

    2013-01-01

    The superconducting solenoid magnet prototype for ADS injection-I had been fabricated in Beijing Qihuan Mechanical and Electric Engineer Company and tested in Haerbin Institute of Technology (HIT) in Nov, 2012. Batch magnet production was processed after some major revision from the magnet prototype, they include: removing off the perm-alloy shield, extending the iron yoke, using thin superconducting cable, etc. The first one of the batch magnets was tested in the vertical Dewar in HIT in Sept. 2013. Field measurement was carried out at the same time by the measurement platform that seated on the top of the vertical Dewar. This paper will present the field measurement system design, measurement results and discussion on the residual field from the persistent current effect.

  12. Nanoscale Measurements of Magnetism & Spin Coherence in Semiconductors

    Science.gov (United States)

    2016-06-14

    2015 Approved for Public Release; Distribution Unlimited Final Report: Nanoscale Measurements of Magnetism & Spin Coherence in Semiconductors The...floor Princeton, NJ 08544 -2020 31-Jul-2015 ABSTRACT Final Report: Nanoscale Measurements of Magnetism & Spin Coherence in Semiconductors Report Title...Si-on-insultor devices. These SOI devices will provide the samples required for study of spin coherence at a single spin level in a semiconductor

  13. Magnetic Barkhausen Noise Measurements Using Tetrapole Probe Designs

    Science.gov (United States)

    McNairnay, Paul

    A magnetic Barkhausen noise (MBN) testing system was developed for Defence Research and Development Canada (DRDC) to perform MBN measurements on the Royal Canadian Navy's Victoria class submarine hulls that can be correlated with material properties, including residual stress. The DRDC system was based on the design of a MBN system developed by Steven White at Queen's University, which was capable of performing rapid angular dependent measurements through the implementation of a flux controlled tetrapole probe. In tetrapole probe designs, the magnetic excitation field is rotated in the surface plane of the sample under the assumption of linear superposition of two orthogonal magnetic fields. During the course of this work, however, the validity of flux superposition in ferromagnetic materials, for the purpose of measuring MBN, was brought into question. Consequently, a study of MBN anisotropy using tetrapole probes was performed. Results indicate that MBN anisotropy measured under flux superposition does not simulate MBN anisotropy data obtained through manual rotation of a single dipole excitation field. It is inferred that MBN anisotropy data obtained with tetrapole probes is the result of the magnetic domain structure's response to an orthogonal magnetization condition and not necessarily to any bulk superposition magnetization in the sample. A qualitative model for the domain configuration under two orthogonal magnetic fields is proposed to describe the results. An empirically derived fitting equation, that describes tetrapole MBN anisotropy data, is presented. The equation describes results in terms of two largely independent orthogonal fields, and includes interaction terms arising due to competing orthogonally magnetized domain structures and interactions with the sample's magnetic easy axis. The equation is used to fit results obtained from a number of samples and tetrapole orientations and in each case correctly identifies the samples' magnetic easy axis.

  14. A New Measurement of the Muon Magnetic Anomaly

    CERN Document Server

    Jungmann, Klaus; Bunce, G M; Carey, R M; Cushman, P B; Danby, G T; Debevec, P T; Deng, H; Denninger, W; Dhawan, S K; Druzhinin, V P; Duong, L; Earle, W; Efstathiadis, E F; Farley, Francis J M; Fedotovich, G V; Giron, S; Gray, F; Grosse-Perdekamp, M; Grossmann, A; Haeberlen, U; Hazen, E S; Hertzog, D W; Hughes, V W; Iwasaki, M; Kawall, D; Kawamura, M; Khazin, B I; Kindem, J; Krienen, F; Kronkvist, I J; Larsen, R; Lee, Y Y; Logashenko, I B; McNabb, R; Meng, W; Mi, J L; Miller, J P; Morse, W M; Nikas, D; Onderwater, Gerco; Orlov, Yu F; Ozben, C; Pai, C; Paley, J M; Polly, C; Pretz, J; Prigl, R; zu Putlitz, Gisbert; Redin, S I; Rind, O; Roberts, B L; Ryskulov, N M; Sedykh, S N; Semertzidis, Y K; Shatunov, Yu M; Solodov, E P; Sossong, M; Steinmetz, A; Sulak, Lawrence R; Timmermans, C; Trofimov, A V; Urner, D; Walter, P V; Warburton, D; Winn, D; Yamamoto, A; Zimmerman, D

    2000-01-01

    The muon magnetic anomaly may contain contributions from physics beyond thestandard model. At the Brookhaven National Laboratory (BNL) a precisionexperiment aims for a measurement of the muon magnetic anomaly $a_{\\mu}$ to0.35 ppm, where conclusions about various theoretical approaches beyondstandard theory can be expected. The difference between the spin precession andcyclotron frequencies is measured in a magnetic storage ring with highlyhomogeneous field. Data taking is in progress and part of all recorded data hasbeen analyzed. Combining all experimental results to date yields preliminarily$a_{\\mu}(expt)=1~165~921(5) \\cdot 10^{-9}$ (4 ppm) in agreement with standardtheory.

  15. Macroscopic theory for capillary-pressure hysteresis.

    Science.gov (United States)

    Athukorallage, Bhagya; Aulisa, Eugenio; Iyer, Ram; Zhang, Larry

    2015-03-03

    In this article, we present a theory of macroscopic contact angle hysteresis by considering the minimization of the Helmholtz free energy of a solid-liquid-gas system over a convex set, subject to a constant volume constraint. The liquid and solid surfaces in contact are assumed to adhere weakly to each other, causing the interfacial energy to be set-valued. A simple calculus of variations argument for the minimization of the Helmholtz energy leads to the Young-Laplace equation for the drop surface in contact with the gas and a variational inequality that yields contact angle hysteresis for advancing/receding flow. We also show that the Young-Laplace equation with a Dirichlet boundary condition together with the variational inequality yields a basic hysteresis operator that describes the relationship between capillary pressure and volume. We validate the theory using results from the experiment for a sessile macroscopic drop. Although the capillary effect is a complex phenomenon even for a droplet as various points along the contact line might be pinned, the capillary pressure and volume of the drop are scalar variables that encapsulate the global quasistatic energy information for the entire droplet. Studying the capillary pressure versus volume relationship greatly simplifies the understanding and modeling of the phenomenon just as scalar magnetic hysteresis graphs greatly aided the modeling of devices with magnetic materials.

  16. Magnetometer for measuring planetary magnetic fields

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Brauer, Peter

    The investigation of the magnetism of the Solar system planets is became one of the important issues for understanding their evolution and history. This has special relevance at Mars after the NASA MGS mission unexpectedly detected higher crustal magnetic anomalies than those existing on Earth...... satellite, the instrument (including hardness) weights less than 1 kg and the electronics unit (featuring redundancy) of the instrument and the sensor has dimensions of 100x100x40 mm and 54x46x33 mm. For a lander, station and/or aerial platform, the instrument can be delivered for direct assembly in a board....... In this case the weight is less than 0.25 kg. And the electronics unit and the sensor have dimensions of 100x70x12 mm and 45x28x30 mm, respectively. In order to determine the orientation of the magnetometer, a star tracker providing high precision attitude can be used for an orbiting satellite. For lander...

  17. Measurement of interaction force between small distances sandwiched with magnetic fluid under magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Miyazaki, T.; Shibayama, A.; Sato, T.; Fujita, T. E-mail: fujita@ipc.akita-u.ac.jp

    2002-11-01

    In this contribution, the interactive force measurement between 10 nm distance under magnetic field is carried out. Previous measurement of the interactive force is reported by Israelachivili et al. However, its measurement under magnetic field has not been performed. The methodology described in this paper is easier as the distance between two surfaces is not measured optically but dynamically. Therefore, it is different from the previous reported studies. Based on the results of the measurement of the interactive force, the diameter of the particle suspended in a solution under magnetic field is also estimated. Moreover, it may be predictable how the clusters have been formed. The method described will be very useful for new productions based on magnetic fluid.

  18. Prospects for x-ray polarimetry measurements of magnetic fields in magnetized liner inertial fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Lynn, Alan G., E-mail: lynn@ece.unm.edu; Gilmore, Mark [Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2014-11-15

    Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compress a magnetized seed plasma may generate peak magnetic fields ∼10{sup 4} T (100 Megagauss) over small volumes (∼10{sup −10}m{sup 3}) at high plasma densities (∼10{sup 28}m{sup −3}) on 100 ns time scales. Such conditions are extremely challenging to diagnose. We discuss the possibility of, and issues involved in, using polarimetry techniques at x-ray wavelengths to measure magnetic fields under these extreme conditions.

  19. Prospects for x-ray polarimetry measurements of magnetic fields in magnetized liner inertial fusion plasmas

    Science.gov (United States)

    Lynn, Alan G.; Gilmore, Mark

    2014-11-01

    Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compress a magnetized seed plasma may generate peak magnetic fields ˜104 T (100 Megagauss) over small volumes (˜10-10m3) at high plasma densities (˜1028m-3) on 100 ns time scales. Such conditions are extremely challenging to diagnose. We discuss the possibility of, and issues involved in, using polarimetry techniques at x-ray wavelengths to measure magnetic fields under these extreme conditions.

  20. Prospects for x-ray polarimetry measurements of magnetic fields in magnetized liner inertial fusion plasmas.

    Science.gov (United States)

    Lynn, Alan G; Gilmore, Mark

    2014-11-01

    Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compress a magnetized seed plasma may generate peak magnetic fields ∼10(4) T (100 Megagauss) over small volumes (∼10(-10)m(3)) at high plasma densities (∼10(28)m(-3)) on 100 ns time scales. Such conditions are extremely challenging to diagnose. We discuss the possibility of, and issues involved in, using polarimetry techniques at x-ray wavelengths to measure magnetic fields under these extreme conditions.

  1. Magnetic hysteresis and magnetic flux patterns measured by acoustically stimulated electromagnetic response in a steel plate

    Science.gov (United States)

    Yamada, Hisato; Watanabe, Kakeru; Ikushima, Kenji

    2015-08-01

    Magnetic hysteresis loops are measured by ultrasonic techniques and used in visualizing the magnetic-flux distribution in a steel plate. The piezomagnetic coefficient determines the amplitude of acoustically stimulated electromagnetic (ASEM) fields, yielding the hysteresis behavior of the intensity of the ASEM response. By utilizing the high correspondence of the ASEM response to the magnetic-flux density, we image the specific spatial patterns of the flux density formed by an artificial defect in a steel plate specimen. Magnetic-flux probing by ultrasonic waves is thus shown to be a viable method of nondestructive material inspection.

  2. Measurement of clottability of fibrin polymers using magnetic orientation

    Science.gov (United States)

    Iwasaka, M.; Ueno, S.; Tsuda, H.

    1996-04-01

    Fibrin polymers, as a kind of diamagnetic material, are oriented parallel to the direction of magnetic fields. We investigated the polymerization of partially digested fibrinogens in an 8 T magnetic field in order to observe the clotting ability of various sizes of fibrinogen fractions using a magnetic orientation technique. We purified high-molecular weight fraction (F1) and low-molecular weight fraction from human fibrinogen (F2). Fibrin gels were formed in an 8 T magnetic field for 9 h, and transmittancies were measured to evaluate the degree of magnetic orientation. The results show that a lack at the C-terminal half of one Aα chain did not affect the magnetic orientation of fibrin. We also investigated the effect of the digestion of fibrinogen by plasmin on the magnetic orientation of fibrin. The result shows that partially digested fibrin molecules also orient in an 8 T magnetic field. However, the degree of magnetic orientation significantly decreases when fragment X and fragment Y appear.

  3. Design, manufacture and measurements of permanent dipole magnets for DIRAC

    CERN Document Server

    Vorozhtsov, A; Kasaei, S; Solodko, E; Thonet, P A; Tommasini, D

    2013-01-01

    The one of the aim of the DIRAC experiment is the observation of the long-lived π+π- atoms, using the proton beam of the CERN Proton Synchrotron [1]. Two dipole magnets are needed for the for the DIRAC experiment as high resolution spectrometers. The dipole magnet will be used to identify the long-lived atoms on the high level background of π+π- pairs produced simultaneously with π+π- atoms. The proposed design is a permanent magnet dipole with a mechanical aperture of 60 mm. The magnet, of a total physical length of 66 mm, is based on Sm2Co17 blocks and provides an integrated field strength of 24·10-3 T×m. The Sm2Co17 was chosen as a material for the permanent magnet blocks due to its radiation hardness and weaker temperature dependence. The magnetic field quality is determined by 2 ferromagnetic poles, aligned together with the permanent magnets blocks. The paper describes the design, manufacture and magnetic measurements of the magnets.

  4. Macroscopic-microscopic mass models

    CERN Document Server

    Nix, J R; Nix, J Rayford; Moller, Peter

    1995-01-01

    We discuss recent developments in macroscopic-microscopic mass models, including the 1992 finite-range droplet model, the 1992 extended-Thomas-Fermi Strutinsky-integral model, and the 1994 Thomas-Fermi model, with particular emphasis on how well they extrapolate to new regions of nuclei. We also address what recent developments in macroscopic-microscopic mass models are teaching us about such physically relevant issues as the nuclear curvature energy, a new congruence energy arising from a greater-than-average overlap of neutron and proton wave functions, the nuclear incompressibility coefficient, and the Coulomb redistribution energy arising from a central density depression. We conclude with a brief discussion of the recently discovered rock of metastable superheavy nuclei near 272:110 that had been correctly predicted by macroscopic-microscopic models, along with a possible new tack for reaching an island near 290:110 beyond our present horizon.

  5. Detecting low concentrations of plutonium hydride with magnetization measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Wook; Mun, E. D.; Baiardo, J. P.; Zapf, V. S.; Mielke, C. H. [National High Magnetic Field Laboratory, MPA-CMMS, Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545 (United States); Smith, A. I.; Richmond, S.; Mitchell, J.; Schwartz, D. [Nuclear Material Science Group, MST-16, LANL, Los Alamos, New Mexico 87545 (United States)

    2015-02-07

    We report the formation of plutonium hydride in 2 at. % Ga-stabilized δ-Pu, with 1 at. % H charging. We show that magnetization measurements are a sensitive, quantitative measure of ferromagnetic plutonium hydride against the nonmagnetic background of plutonium. It was previously shown that at low hydrogen concentrations, hydrogen forms super-abundant vacancy complexes with plutonium, resulting in a bulk lattice contraction. Here, we use magnetization, X-ray, and neutron diffraction measurements to show that in addition to forming vacancy complexes, at least 30% of the H atoms bond with Pu to precipitate PuH{sub x} on the surface of the sample with x ∼ 1.9. We observe magnetic hysteresis loops below 40 K with magnetic remanence, consistent with ferromagnetic PuH{sub 1.9}.

  6. Adsorption modeling for macroscopic contaminant dispersal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Axley, J.W.

    1990-05-01

    Two families of macroscopic adsorption models are formulated, based on fundamental principles of adsorption science and technology, that may be used for macroscopic (such as whole-building) contaminant dispersal analysis. The first family of adsorption models - the Equilibrium Adsorption (EA) Models - are based upon the simple requirement of equilibrium between adsorbent and room air. The second family - the Boundary Layer Diffusion Controlled Adsorption (BLDC) Models - add to the equilibrium requirement a boundary layer model for diffusion of the adsorbate from the room air to the adsorbent surface. Two members of each of these families are explicitly discussed, one based on the linear adsorption isotherm model and the other on the Langmuir model. The linear variants of each family are applied to model the adsorption dynamics of formaldehyde in gypsum wall board and compared to measured data.

  7. Pressure and Magnetics Measurements of Single and Merged Jets

    Science.gov (United States)

    Messer, S.; Case, A.; Brockington, S.; Bomgardner, R.; Witherspoon, F. D.

    2010-11-01

    We present pressure and magnetic data from both a single full scale coaxial gun and from the merging of jets from several minirailguns. The magnetic probes measure all three components of field, and include an array of probes inside the coaxial gun. Magnetic measurements beyond the muzzle of the gun show the scale of currents trapped in the plasma plume. The pressure probe measures adiabatic stagnation pressure and shows how this quantity decreases with distance from the gun as well as the changes in stagnation pressure through the merge process. Stagnation pressure is influenced by density, temperature, and velocity, and serves as a check on spectroscopic and interferometer measurements. Unlike optical measurements, stagnation pressure is taken at a definite location. These guns are early prototypes of guns to be installed on the Plasma Liner eXperiment at LANL. The jet-merging results are reviewed in the context of what is expected for PLX.

  8. Calculated and measured fields in superferric wiggler magnets

    Energy Technology Data Exchange (ETDEWEB)

    Blum, E.B.; Solomon, L. [Brookhaven National Lab., Upton, NY (United States)

    1995-02-01

    Although Klaus Halbach is widely known and appreciated as the originator of the computer program POISSON for electromagnetic field calculation, Klaus has always believed that analytical methods can give much more insight into the performance of a magnet than numerical simulation. Analytical approximations readily show how the different aspects of a magnet`s design such as pole dimensions, current, and coil configuration contribute to the performance. These methods yield accuracies of better than 10%. Analytical methods should therefore be used when conceptualizing a magnet design. Computer analysis can then be used for refinement. A simple model is presented for the peak on-axis field of an electro-magnetic wiggler with iron poles and superconducting coils. The model is applied to the radiator section of the superconducting wiggler for the BNL Harmonic Generation Free Electron Laser. The predictions of the model are compared to the measured field and the results from POISSON.

  9. Scaling macroscopic aquatic locomotion

    Science.gov (United States)

    Gazzola, Mattia; Argentina, Mederic; Mahadevan, Lakshminarayanan

    2014-11-01

    Inertial aquatic swimmers that use undulatory gaits range in length L from a few millimeters to 30 meters, across a wide array of biological taxa. Using elementary hydrodynamic arguments, we uncover a unifying mechanistic principle characterizing their locomotion by deriving a scaling relation that links swimming speed U to body kinematics (tail beat amplitude A and frequency ω) and fluid properties (kinematic viscosity ν). This principle can be simply couched as the power law Re ~ Swα , where Re = UL / ν >> 1 and Sw = ωAL / ν , with α = 4 / 3 for laminar flows, and α = 1 for turbulent flows. Existing data from over 1000 measurements on fish, amphibians, larvae, reptiles, mammals and birds, as well as direct numerical simulations are consistent with our scaling. We interpret our results as the consequence of the convergence of aquatic gaits to the performance limits imposed by hydrodynamics.

  10. A Macroscopic Analogue of the Nuclear Pairing Potential

    Science.gov (United States)

    Dunlap, Richard A.

    2013-01-01

    A macroscopic system involving permanent magnets is used as an analogue to nucleons in a nucleus to illustrate the significance of the pairing interaction. This illustrates that the view of the total nuclear energy based only on the nucleon occupancy of the energy levels can yield erroneous results and it is only when the pairing interaction is…

  11. Diagnosis of bladder tumours in patients with macroscopic haematuria

    DEFF Research Database (Denmark)

    Gandrup, Karen L; Løgager, Vibeke B; Bretlau, Thomas

    2015-01-01

    OBJECTIVE: The aim of this study was to compare split-bolus computed tomography urography (CTU), magnetic resonance urography (MRU) and flexible cystoscopy in patients with macroscopic haematuria regarding the diagnosis of bladder tumours. MATERIALS AND METHODS: In this prospective study, 150...

  12. Magnetic-Field-Response Measurement-Acquisition System

    Science.gov (United States)

    Woodward, Stanley E.; Shams, Qamar A.; Fox, Robert L.; Taylor, Bryant D.

    2006-01-01

    A measurement-acquisition system uses magnetic fields to power sensors and to acquire measurements from sensors. The system alleviates many shortcomings of traditional measurement-acquisition systems, which include a finite number of measurement channels, weight penalty associated with wires, use limited to a single type of measurement, wire degradation due to wear or chemical decay, and the logistics needed to add new sensors. Eliminating wiring for acquiring measurements can alleviate potential hazards associated with wires, such as damaged wires becoming ignition sources due to arcing. The sensors are designed as electrically passive inductive-capacitive or passive inductive-capacitive-resistive circuits that produce magnetic-field-responses. One or more electrical parameters (inductance, capacitance, and resistance) of each sensor can be variable and corresponds to a measured physical state of interest. The magnetic-field- response attributes (frequency, amplitude, and bandwidth) of the inductor correspond to the states of physical properties for which each sensor measures. For each sensor, the measurement-acquisition system produces a series of increasing magnetic-field harmonics within a frequency range dedicated to that sensor. For each harmonic, an antenna electrically coupled to an oscillating current (the frequency of which is that of the harmonic) produces an oscillating magnetic field. Faraday induction via the harmonic magnetic fields produces an electromotive force and therefore a current in the sensor. Once electrically active, the sensor produces its own harmonic magnetic field as the inductor stores and releases magnetic energy. The antenna of the measurement- acquisition system is switched from a transmitting to a receiving mode to acquire the magnetic-field response of the sensor. The rectified amplitude of the received response is compared to previous responses to prior transmitted harmonics, to ascertain if the measurement system has detected a

  13. Ultrafast Magnetism Dynamics Measure Using Tabletop Ultrafast EUV Sources

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Thomas J. [NIST; Murnane, Margaret [University of Colorado

    2013-08-21

    In our work to date, we made two significant advances. First we demonstrated element-selective demagnetization dynamics for the first time, with a record time resolution for x-ray probing of 55 fs. Second, in new work, we were able to probe the timescale of the exchange interaction in magnetic materials, also for the first time. Our measurements were made using the transverse magneto-optic Kerr effect (T-MOKE) geometry, since the reflectivity of a magnetic material changes with the direction of the magnetization vector of a surface. In our experiment, we periodically reversed the magnetization direction of a grating structure made of Permalloy (Ni80Fe20) using an external magnetic field. To achieve maximum contrast, we used HHG light spanning the M-shell (3p) absorption edges of Fe and Ni. Our characterization of the static magnetization of a Permalloy sample shows high magnetic asymmetry at photon energies just above and below the absorption edges at 55 eV and 65 eV, respectively. This result is in excellent agreement with measurements done on the same using a synchrotron source.

  14. Satellite measurements of the earth's crustal magnetic field

    Science.gov (United States)

    Schnetzler, C. C.

    1989-01-01

    The literature associated with the Magsat mission has evaluated the capabilities and limitations of satellite measurements of the earth's crustal magnetic field, and demonstrated that there exists a 300-3000 km magnetic field, related to major features in the earth's crust, which is primarily caused by induction. Due to its scale and sensitivity, satellite data have been useful in the development of models for such large crustal features as subduction zones, submarine platforms, continental accretion boundaries, and rifts. Attention is presently given to the lack of agreement between laboratory and satellite estimates of lower crustal magnetization.

  15. Complex susceptibility measurements of a suspension of magnetic beads

    Energy Technology Data Exchange (ETDEWEB)

    Fannin, P.C. [Department of Electronic and Electrical Engineering, Trinity College, Dublin 2 (Ireland)]. E-mail: pfannin@tcd.ie; Mac Oireachtaigh, C. [Department of Electronic and Electrical Engineering, Trinity College, Dublin 2 (Ireland); Cohen-Tannoudji, L. [Laboratoire Colloides et Materiaux Divises, CNRS UMR7612, ESPCI, 10 Rue Vauquelin, F-75005 Paris (France); Bertrand, E. [Laboratoire Colloides et Materiaux Divises, CNRS UMR7612, ESPCI, 10 Rue Vauquelin, F-75005 Paris (France); Bibette, J. [Laboratoire Colloides et Materiaux Divises, CNRS UMR7612, ESPCI, 10 Rue Vauquelin, F-75005 Paris (France)

    2006-05-15

    Measurements of the frequency and field dependence of the complex magnetic susceptibility, {chi}{sub s}({omega},H)={chi}{sub s}{sup '}({omega},H)-i{chi}{sub s}{sup '}'({omega},H), of a suspension of magnetic beads in water over the frequency range 200Hz to 1MHz are presented. The magnetic polarizing field, H, is applied to the sample, first in a forward direction and then in a reverse direction and from a plot of the static susceptibility, {chi}{sub 0S}, against polarizing field H, the existence of a hysteresis effect is demonstrated.

  16. A magnetic suspension system for measuring liquid density

    Directory of Open Access Journals (Sweden)

    Luz María Centeno González

    2013-04-01

    Full Text Available Density is a derived quantity of mass and length; it is defined as mass per volume unit and its SI unit is kg/m3. National metrology institutes have been designing and building their own magnetic suspension systems during the last 5 decades for making fluid density measurements; this has allowed them to carry out research into liquids and gases’ physical characteristics. This paper was aimed at designing and developing a magnetic suspension system for a magnetic balance used in determining liquid density to be used in CENAM’s metrology density laboratories.

  17. Magnetic field, closed orbit, and energy measurement in the Bevatron

    Energy Technology Data Exchange (ETDEWEB)

    Crebbin, K.C.

    1981-11-01

    This report provides the information necessary for a better evaluation of particle energy in the Bevatron. Previously, the nominal magnetic field value and radius were used to calculate the value for the kinetic energy of the particle. This value was good to a few percent. Today, more and more experimenters would like to know the energy to a more precise value. To this end, corrections to the measured magnetic field values and the radial closed orbit are provided.

  18. Magnetic rotation imaging method to measure the geomagnetic field

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A new imaging method for measuring the geomagnetic field based on the magnetic rotation effect is put forward. With the help of polarization property of the sunlight reflected from the ground and the magnetic rotation of the atmosphere, the geomagnetic field can be measured by an optical system installed on a satellite. According to its principle, the three-dimensional image of the geomagnetic field can be obtained. The measuring speed of this method is very high, and there is no blind spot and distortion. In this paper, the principle of this method is presented, and some key problems are discussed.

  19. The new magnetic measurement system at the Advanced Photon Source.

    Energy Technology Data Exchange (ETDEWEB)

    Eidelman, Y.; Deriy, B.; Makarov, O.; Vasserman, I.

    2002-03-15

    A new system for precise measurements of the field integrals and multipole components of the APS magnetic insertion devices is described. A stretched coil is used to measure magnetic field characteristics. The hardware includes a number of servomotors to move (translate or rotate) the coil and a fast data acquisition board to measure the coil signal. A PC under Linux is used as a control workstation. The user interface is written as a Tcl/tk script; the hardware is accessed from the script through a shared C-library. A description of the hardware system and the control program is given.

  20. The new Magnetic Measurement System at the Advanced Photon Source

    CERN Document Server

    Eidelman, Y; Makarov, O P; Vasserman, I B; Eidelman, Yu.

    2001-01-01

    A new system for precise measurements of the field integrals and multipole components of the APS magnetic insertion devices is described. A stretched coil is used to measure magnetic field characteristics. The hardware includes a number of servomotors to move (translate or rotate) the coil and a fast data acquisition board to measure the coil signal. A PC under Linux is used as a control workstation. The user interface is written as a Tcl/tk script. The hardware is accessed from the script through a shared C-library. A description of the hardware system and the control program is given.

  1. Measuring the Muon g-2 Magnetic Storage Field Via Proton Nuclear Magnetic Resonance

    Science.gov (United States)

    Smith, Matthias; Muon g-2 Collaboration Collaboration

    2016-03-01

    The Muon g - 2 experiment at Fermilab aims to measure the muon anomalous magnetic moment, aμ, to a precision of 140 ppb, using a technique that determines the muon spin precession frequency in the highly uniform magnetic field of a storage ring. Both precession frequency and field determination contribute equally to the final systematic uncertainty. The magnetic field is determined from the measurement of free induction decay (FID) signals provided by a matrix of custom proton nuclear magnetic resonance (pNMR) probes. FID simulations show that we can achieve the required precision for extraction of field values compared to systematic contributions. The recently powered muon storage ring is providing data to evaluate the pNMR measurement results. We will describe the performance to date of this system.

  2. Anisotropic mechanical properties of magnetically aligned fibrin gels measured by magnetic resonance elastography.

    Science.gov (United States)

    Namani, Ravi; Wood, Matthew D; Sakiyama-Elbert, Shelly E; Bayly, Philip V

    2009-09-18

    The anisotropic mechanical properties of magnetically aligned fibrin gels were measured by magnetic resonance elastography (MRE) and by a standard mechanical test: unconfined compression. Soft anisotropic biomaterials are notoriously difficult to characterize, especially in vivo. MRE is well-suited for efficient, non-invasive, and non-destructive assessment of shear modulus. Direction-dependent differences in shear modulus were found to be statistically significant for gels polymerized at magnetic fields of 11.7 and 4.7 T compared to control gels. Mechanical anisotropy was greater in the gels polymerized at the higher magnetic field. These observations were consistent with results from unconfined compression tests. Analysis of confocal microscopy images of gels showed measurable alignment of fibrils in gels polymerized at 11.7 T. This study provides direct, quantitative measurements of the anisotropy in mechanical properties that accompanies fibril alignment in fibrin gels.

  3. Uncertainty analysis of the magnetic field measurement by the translating coil method in axisymmetric magnets

    Science.gov (United States)

    Arpaia, Pasquale; De Vito, Luca; Kazazi, Mario

    2016-12-01

    In the uncertainty assessment of magnetic flux measurements in axially symmetric magnets by the translating coil method, the Guide to the Uncertainty in Measurement and its supplement cannot be applied: the voltage variation at the coil terminals, which is the actual measured quantity, affects the flux estimate and its uncertainty. In this paper, a particle filter, implementing a sequential Monte-Carlo method based on Bayesian inference, is applied. At this aim, the main uncertainty sources are analyzed and a model of the measurement process is defined. The results of the experimental validation point out the transport system and the acquisition system as the main contributions to the uncertainty budget.

  4. Estimating effects from trapped magnetic fluxes in superconducting magnetic levitation measurement

    Institute of Scientific and Technical Information of China (English)

    Masakazu Nakanishi

    2008-01-01

    Superconducting magnetic levitation measurement is one of the most promising approaches to define mass standard based on the fundamental physical constants. However, the present system has unknown factors causing error larger than 50 ppm. We examined the effects of magnetic fluxes trapped in the superconducting coil and the superconducting floating body. When fluxes were trapped in either coil or floating body, their effects were able to be cancelled by reversing polarities of current and magnetic field, as had been believed. However, fluxes trapped in both coil and body induced an attractive force between them and caused error. In order to reduce the fluxes, the coil and the floating body should be cooled in low magnetic field in magnetic and electromagnetic shields.

  5. New insights into chromospheric structures from vector magnetic field measurements

    Science.gov (United States)

    Lagg, A.

    During the last decade advances in instrumentation atomic physics and modeling have greatly improved the access to the chromospheric magnetic field vector High sensitivity polarimeters like the Tenerife Infrared Polarimeter TIP2 VTT or the Spectro-Polarimeter for Infrared and Optical Regions SPINOR HAO lead to reliable Zeeman measurements using the He I 10830 nm triplet Theoretical modeling of the Hanle and the Paschen Back effect helped to significantly improve the analysis of polarization measurements in this triplet allowing to directly visualize the magnetic structure of spicules polar prominences and active regions In this presentation I will summarize the results of chromospheric magnetic field measurements using this interesting triplet obtained in the last couple of years and discuss the great potential it has to further uncover the complex structure of the chromosphere

  6. The FORS1 catalogue of stellar magnetic field measurements

    CERN Document Server

    Bagnulo, S; Landstreet, J D; Izzo, C

    2015-01-01

    The FORS1 instrument on the ESO Very Large Telescope was used to obtain low-resolution circular polarised spectra of nearly a thousand different stars, with the aim of measuring their mean longitudinal magnetic fields. A catalogue of FORS1 magnetic measurements would provide a valuable resource with which to better understand the strengths and limitations of this instrument and of similar low-dispersion, Cassegrain spectropolarimeters. However, FORS1 data reduction has been carried out by a number of different groups using a variety of reduction and analysis techniques. Our understanding of the instrument and our data reduction techniques have both improved over time. A full re-analysis of FORS1 archive data using a consistent and fully documented algorithm would optimise the accuracy and usefulness of a catalogue of field measurements. Based on the ESO FORS pipeline, we have developed a semi-automatic procedure for magnetic field determinations, which includes self-consistent checks for field detection relia...

  7. Application of New Type BP Neural Networks for Magnetic Measurement

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Magnetic measurement is a typical inverse problem in Biomedical field. In this kind of problem we always need to locate the positions and moments of one or more magnetic dipoles. Although using the traditional methods to solve this kind of inverse problem has all kinds of shortcomings, BPNN (Back Propagation Neural Networks) method can be used to solve this typical inverse problem fast enough for real time measurement. In the traditional BPNN method, gradient descent search method is performed for error propagation. In this paper the authors propose a new algorithm that Newton method is performed for error propagation. For the cost function is highly nonconvex in the magnetic measurement problem, the new kind of BPNN can get convergent results quickly and precisely. A simulation result for this method is also presented.

  8. Analyzing Extragalactic Magnetic Fields Using Faraday Rotation Measure Synthesis

    Science.gov (United States)

    Pare, Dylan; Wang, Q. Daniel; Kamieneski, Patrick; Sullivan, Kendall

    2017-01-01

    Extragalactic magnetic fields are a poorly understood element of galaxies that are likely to play an important role in galaxy formation and evolution. Until recently, however, there was no way to observe these fields to a high level of detail, making it difficult to map the spatial distribution of these fields to any high degree of accuracy. Fortunately, a new technique known as Faraday Rotation Measure Synthesis allows for a more precise analysis of galactic magnetism. This technique uses the observed Faraday rotation of polarized emission from background sources to map the magnetic field of a foreground galaxy. This Faraday rotation occurs when the polarized emission encounters ionized, magnetized gas within the galaxy, causing the emission to be rotated by an amount proportional the magnetic field subjected to the ionized gas. Working as part of CHANG-ES (Continuum HAlos in Nearby Galaxies - an EVLA Survey), we have applied this technique in order to learn about the distribution of magnetic fields in the disks and halos of edge-on spiral galaxies. We will present maps of the galactic magnetic fields of CHANG-ES galaxies using this technique, indicating the potential of this technique in successfully mapping these distant fields.

  9. The methods of the LHC magnets' magnetic axis location measurement

    Energy Technology Data Exchange (ETDEWEB)

    Bottura, L.; Buzio, M.; Deferne, G.; Sievers, P.; Smirnov, N.; Villar, F.P.; Walckiers, L. [CERN, Conseil Europeen pour la recherche nucleaire, Laboratoire europeen pour la physique des particules, Geneve (Switzerland)

    1999-07-01

    More than 8 thousands LHC magnets of various types will be extensively measured during series magnetic test at both room and superfluid helium temperature. The precise knowledge of the magnetic axis positioning is vital for the alignment of those magnets in the tunnel. The most efficient and cost effective method with rotating pick up coil is chosen currently as a baseline for series measurement. The position of the measuring coil axis herewith is measured with a dedicated optical system. The deflection of the light beam in the air due to temperature gradient either passing through the cold bore when the magnet excited for warm measurement or through the anti-cryostat during cold measurement can reach magnitudes significantly exceeding tolerance and therefore is a critical issue. We present studies of the light deflection in 10 m long dipole at warm and cold and propose means to reduce it. The result of the dipole centring powered in Quadrupole Configured Dipole (QCD) or 'ugly quad' configuration and correlation with centring based on high order harmonics are presented as well. (authors)

  10. MESSENGER Measurements of Mercury's Magnetic Field during the First Flyby

    Science.gov (United States)

    Slavin, James A.; Boardsen, S. A.; Acuna, M. H.; Anderson, B. J.; Johnson, C. L.; Korth, H.; Krimigis, S. M.; McNutt, R. L., Jr.; Purucker, M. E.; Solomon, S. C.

    2008-01-01

    On 14 January 2008 the MESSENGER spacecraft will encounter Mercury for the first time. Depending upon the solar wind conditions, this initial flyby will return Magnetometer measurements of Mercury's magnetic field over a time interval lasting between - 30 md 60 min. Closest approach for MESSENGER is targeted for an altitude of 200 km as compared with the 707 krn and 327 km attained by Mariner 10 on 29 March 1974 and 16 March 1975, respectively. Furthermore, the differences in the MESSENGER and Mariner 10 encounter trajectories, with respect both to magnetospheric and body-fixed coordinates are highly complementary and expected to lead to significant improvements in our knowledge of Mercury's magnetic field. We present an overview of the MESSENGER magnetic field observations, an initial subtraction of the magnetic fields attributable to magnetospheric current systems from the total measured magnetic field, and an improved model of Mercury's intrinsic magnetic field. We also discuss the expected advances afforded by the two additional MESSENGER flybys, which occur in October 2008 and September 2009, as well as the orbital phase that will begin in March 201 1.

  11. Correlated Biofilm Imaging, Transport and Metabolism Measurements via Combined Nuclear Magnetic Resonance and Confocal Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mclean, Jeffrey S.; Ona, Ositadinma; Majors, Paul D.

    2008-02-18

    Bacterial biofilms are complex, three-dimensional, communities that are found nearly everywhere in nature1 and are being recognized as the cause of treatment-resistant infections1 2. Advanced methods are required to characterize their collective and spatial patterns of metabolism however most techniques are invasive or destructive. Here we describe the use of a combined confocal laser scanning microscopy (CLSM) and nuclear magnetic resonance (NMR) microscopy system to monitor structure, mass transport, and metabolism in active biofilms. Non-invasive NMR methods provide macroscopic structure along with spatially-resolved metabolite profiles and diffusion measurements. CLSM enables monitoring of cells by fluorescent protein reporters to investigate biofilm structure and gene expression concurrently. A planar sample chamber design facilitates depth-resolved measurements on 140 nL sample volumes under laminar flow conditions. The techniques and approaches described here are applicable to environmental and medically relevant microbial communities, thus providing key metabolic information for promoting beneficial biofilms and treating associated diseases.

  12. Advanced multipoles for accelerator magnets theoretical analysis and their measurement

    CERN Document Server

    Schnizer, Pierre

    2017-01-01

    This monograph presents research on the transversal beam dynamics of accelerators and evaluates and describes the respective magnetic field homogeneity.  The widely used cylindrical circular multipoles have disadvantages for elliptical apertures or curved trajectories, and the book also introduces new types of advanced multipole magnets, detailing their application, as well as the numerical data and measurements obtained. The research presented here provides more precise descriptions of the field and better estimates of the beam dynamics. Moreover, the effects of field inhomogeneity can be estimated with higher precision than before. These findings are further elaborated to demonstrate their usefulness for real magnets and accelerator set ups, showing their advantages over cylindrical circular multipoles. The research findings are complemented with data obtained from the new superconducting beam guiding magnet models (SIS100) for the FAIR (Facility for Antiproton and Ion Research) project.  Lastly, the book...

  13. Using optical soliton stability for magnetic field measurement

    Science.gov (United States)

    Şchiopu, IonuÅ£ Romeo; ǎgulinescu, Andrei, Dr; Marinescu, Andrei

    2015-02-01

    In this paper we propose a novel optical method for measuring the circular magnetic field. In practice, many situations may appear in which there are difficulties in measuring the magnetic field, as inside coils, motors etc., where the magnetic field lines are circular or elliptical. The proposed method, applied for measuring the current on high voltage lines, strongly benefits from the advantages that it offers as compared to classical solutions based on the inductive principle. Some of the advantages of optoelectronic and optic measurement methods have a real importance. These advantages consist in: avoiding the use of energy intensive materials (Cu, Fe etc.), reducing the weight of the measuring system, reducing at the minimum the fire danger due to the use of paper-oil insulation in high voltage devices etc. The novelty of our proposed method consists in using the electromagnetic radiation in ultrashort pulses, having a relatively large frequency band and a much improved resistance to external perturbations, for measuring the circular magnetic field generated from the current of high voltage lines, inside power transformers or high power motors.

  14. The uncertainties of magnetic properties measurements of electrical sheet steel

    CERN Document Server

    Ahlers, H

    2000-01-01

    In this work, uncertainties in measurements of magnetic properties of Epstein- and single-sheet samples have been determined according to the 'Guide To The Expression Of Uncertainty In Measurement', [International Organization for Standardization (1993)]. They were calculated for the results at predicted values of parameters taking into account the non-linear dependences. The measurement results and the uncertainties are calculated simultaneously by a computer program.

  15. Progress in magnetic measurements. Jiki keisoku gijutsu no saikin no ugoki

    Energy Technology Data Exchange (ETDEWEB)

    Shirae, K. (Osaka Univ., Osaka (Japan). Faculty of Engineering and Science)

    1992-09-10

    Although the measurement of magnetic field in the space such as the earth magnetism is firstly pointed out as a measurement of magnetism, in addition to it, the measurement of the property of magnetic substance and the magnetic domain is included in this range. The broadening of magnetic field extends currently from 1fT to over 1MT. The magnetic field more than MT is the one which is said to exist in the blackhole in the end of the cosmos. The magnitude of artificial magnetic field does not reach KT. The superconductive quantum interference device (SQUID) magnetometer is currently a detector for the magnetic field with a highest sensitivity. The property of magnetic material is basically represented by the measurement of magnetization curve, measurement of less and measurement of magnetic permeability. The inside of magnetic substance is subdivided into the magnetic domain. Also the electron microscope demonstrates the powerful influence for the observation of magnetic domain. The measurement of magnetism has also a purpose to wish to find a source generating the magnetism. It is, so-called, one of the inverse problems which presume the cause from the result. That the magnetic domain structure in the inside of magnetic substance is restructed from the measurement of the leakage magnetic field in the magnetic substance and so forth, correspond to this. 10 refs., 6 figs.

  16. Magnetic vortex chirality determination via local hysteresis loops measurements with magnetic force microscopy

    OpenAIRE

    Marco Coïsson; Gabriele Barrera; Federica Celegato; Alessandra Manzin; Franco Vinai; Paola Tiberto

    2016-01-01

    Magnetic vortex chirality in patterned square dots has been investigated by means of a field-dependent magnetic force microscopy technique that allows to measure local hysteresis loops. The chirality affects the two loop branches independently, giving rise to curves that have different shapes and symmetries as a function of the details of the magnetisation reversal process in the square dot, that is studied both experimentally and through micromagnetic simulations. The tip-sample interaction ...

  17. A hybrid data acquisition system for magnetic measurements of accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Hafalia, R.; Joseph, J.; Lizarazo, J.; Martchevsky, M.; Sabbi, G. L.

    2011-06-03

    A hybrid data acquisition system was developed for magnetic measurement of superconducting accelerator magnets at LBNL. It consists of a National Instruments dynamic signal acquisition (DSA) card and two Metrolab fast digital integrator (FDI) cards. The DSA card records the induced voltage signals from the rotating probe while the FDI cards records the flux increment integrated over a certain angular step. This allows the comparison of the measurements performed with two cards. In this note, the setup and test of the system is summarized. With a probe rotating at a speed of 0.5 Hz, the multipole coefficients of two magnets were measured with the hybrid system. The coefficients from the DSA and FDI cards agree with each other, indicating that the numerical integration of the raw voltage acquired by the DSA card is comparable to the performance of the FDI card in the current measurement setup.

  18. Rotating permanent magnet excitation for blood flow measurement.

    Science.gov (United States)

    Nair, Sarath S; Vinodkumar, V; Sreedevi, V; Nagesh, D S

    2015-11-01

    A compact, portable and improved blood flow measurement system for an extracorporeal circuit having a rotating permanent magnetic excitation scheme is described in this paper. The system consists of a set of permanent magnets rotating near blood or any conductive fluid to create high-intensity alternating magnetic field in it and inducing a sinusoidal varying voltage across the column of fluid. The induced voltage signal is acquired, conditioned and processed to determine its flow rate. Performance analysis shows that a sensitivity of more than 250 mV/lpm can be obtained, which is more than five times higher than conventional flow measurement systems. Choice of rotating permanent magnet instead of an electromagnetic core generates alternate magnetic field of smooth sinusoidal nature which in turn reduces switching and interference noises. These results in reduction in complex electronic circuitry required for processing the signal to a great extent and enable the flow measuring device to be much less costlier, portable and light weight. The signal remains steady even with changes in environmental conditions and has an accuracy of greater than 95%. This paper also describes the construction details of the prototype, the factors affecting sensitivity and detailed performance analysis at various operating conditions.

  19. Terrestrial Magnetism in Ottoman Empire: Documents and Measurements

    Science.gov (United States)

    Ozcep, Ferhat

    2016-04-01

    In the modern sense, geophysics started with geomagnetic works in the 1600s in Ottoman geography. The period between 1600 and 1800 includes the measurement of magnetic declination, inclination and magnetic field strength. Before these years, there is a little information, such as how to use a compass, in the Kitab-i Bahriye (the Book of Navigation) of Piri Reis, who is one of the most important mariners of the Ottoman Empire. However, this may not mean that magnetic declination was generally understood. The first Turkish scientific book relating to terrestrial magnetism is the book of Fuyuzat-i Miknatissiye that was translated by Ibrahim Müteferrika and printed in 1731. The subject of this book is earth's magnetism. Magnetic compass was mentioned in several books. These areMuhammed al Awfi's "Jami al- Hikayat" (translated into Turkish by Ibn Arabşah); Piri Reis's Kitab-I Bahriye (The Book of "Navigation" or "Seafaring" or "Sea"); Seydi Ali Reis's "Risale-i Mirat-I Kainat min Alat-I Irtifa" (The Treatise called the Mirror of Universe according to the instrument for measuring Altitude) and Kitab Al-"Muhit" Fi˙Ilm'al-Eflak Va'l Abhur (Book of the Regional Seas and the Science of Astronomy and Navigation). There are two original magnetic declination determinations in Istanbul in 1727 and 1893 by Ottoman Turks. Also, many geomagnetic measurements between 1600 and 1917 were carried out during international campaigns in Ottoman geography.This study was carried out in History and Philosophy of Science, University of Cambridge and supported by Istanbul University Reseach Project Unite (project Numbver: IRP-49162).

  20. Determination of intrinsic damping of perpendicularly magnetized ultrathin films from time-resolved precessional magnetization measurements

    Science.gov (United States)

    Capua, Amir; Yang, See-hun; Phung, Timothy; Parkin, Stuart S. P.

    2015-12-01

    Magnetization dynamics are strongly influenced by damping, namely, the loss of spin angular momentum from the magnetic system to the lattice. An "effective" damping constant αeff is often determined experimentally from the spectral linewidth of the free induction decay of the magnetization after the system is excited to its nonequilibrium state. Such an αeff, however, reflects both intrinsic damping as well as inhomogeneous broadening that arises, for example, from spatial variations of the anisotropy field. In this paper, we compare measurements of the magnetization dynamics in ultrathin nonepitaxial films having perpendicular magnetic anisotropy using two different techniques, time-resolved magneto-optical Kerr effect (TRMOKE) and hybrid optical-electrical ferromagnetic resonance (OFMR). By using an external magnetic field that is applied at very small angles to the film plane in the TRMOKE studies, we develop an explicit closed-form analytical expression for the TRMOKE spectral linewidth and show how this can be used to reliably extract the intrinsic Gilbert damping constant. The damping constant determined in this way is in excellent agreement with that determined from the OFMR method on the same samples. Our studies indicate that the asymptotic high-field approach that is often used in the TRMOKE method to distinguish the intrinsic damping from the effective damping may result in significant error, because such high external magnetic fields are required to make this approach valid that they are out of reach. The error becomes larger at lower intrinsic damping constants and thus may account for the anomalously high damping constants that are often reported in TRMOKE studies. In conventional ferromagnetic resonance (FMR) studies, inhomogeneous contributions can be readily distinguished from intrinsic damping contributions by studying the magnetic field dependence of the FMR linewidth. Using an analogous approach, we show how reliable values of the intrinsic

  1. Paramagnetic ionic liquids for measurements of density using magnetic levitation.

    Science.gov (United States)

    Bwambok, David K; Thuo, Martin M; Atkinson, Manza B J; Mirica, Katherine A; Shapiro, Nathan D; Whitesides, George M

    2013-09-03

    Paramagnetic ionic liquids (PILs) provide new capabilities to measurements of density using magnetic levitation (MagLev). In a typical measurement, a diamagnetic object of unknown density is placed in a container containing a PIL. The container is placed between two magnets (typically NdFeB, oriented with like poles facing). The density of the diamagnetic object can be determined by measuring its position in the magnetic field along the vertical axis (levitation height, h), either as an absolute value or relative to internal standards of known density. For density measurements by MagLev, PILs have three advantages over solutions of paramagnetic salts in aqueous or organic solutions: (i) negligible vapor pressures; (ii) low melting points; (iii) high thermal stabilities. In addition, the densities, magnetic susceptibilities, glass transition temperatures, thermal decomposition temperatures, viscosities, and hydrophobicities of PILs can be tuned over broad ranges by choosing the cation-anion pair. The low melting points and high thermal stabilities of PILs provide large liquidus windows for density measurements. This paper demonstrates applications and advantages of PILs in density-based analyses using MagLev.

  2. Macroscopic quantum oscillator based on a flux qubit

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Mandip, E-mail: mandip@iisermohali.ac.in

    2015-09-25

    In this paper a macroscopic quantum oscillator is proposed, which consists of a flux-qubit in the form of a cantilever. The net magnetic flux threading through the flux-qubit and the mechanical degrees of freedom of the cantilever are naturally coupled. The coupling between the cantilever and the magnetic flux is controlled through an external magnetic field. The ground state of the flux-qubit-cantilever turns out to be an entangled quantum state, where the cantilever deflection and the magnetic flux are the entangled degrees of freedom. A variant, which is a special case of the flux-qubit-cantilever without a Josephson junction, is also discussed. - Highlights: • In this paper a flux-qubit-cantilever is proposed. • Coupling can be varied by an external magnetic field. • Ground state is a macroscopic entangled quantum state. • Ground state of the superconducting-loop-oscillator is a macroscopic quantum superposition. • Proposed scheme is based on a generalized quantum approach.

  3. 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.

  4. Titanium pyrochlore magnets: how much can be learned from magnetization measurements?

    Science.gov (United States)

    Petrenko, O. A.; Lees, M. R.; Balakrishnan, G.

    2011-04-01

    We report magnetization data for several titanium pyrochlore systems measured down to 0.5 K. The measurements, performed on single crystal samples in fields of up to 7 kOe, have captured the essential elements of the previously reported phase transitions in these compounds and have also revealed additional important features overlooked previously either because of the insufficiently low temperatures used, or due to limitations imposed by polycrystalline samples. For the spin-ice pyrochlores Dy2Ti2O7 and Ho2Ti2O7, an unusually slow relaxation of the magnetization has been observed in lower fields, while the magnetization process in higher fields is essentially hysteresis-free and does not depend on sample history. For the XY pyrochlore Er2Ti2O7, the magnetic susceptibility shows nearly diverging behaviour on approach to a critical field, HC = 13.5 kOe, above which the magnetization does not saturate but continues to grow at a significant rate. For the Heisenberg pyrochlore Gd2Ti2O7, the magnetic susceptibility shows a pronounced change of slope at both transition temperatures, TN1 = 1.02 K and TN2 = 0.74 K, contrary to the earlier reports.

  5. Titanium pyrochlore magnets: how much can be learned from magnetization measurements?

    Science.gov (United States)

    Petrenko, O A; Lees, M R; Balakrishnan, G

    2011-04-27

    We report magnetization data for several titanium pyrochlore systems measured down to 0.5 K. The measurements, performed on single crystal samples in fields of up to 7 kOe, have captured the essential elements of the previously reported phase transitions in these compounds and have also revealed additional important features overlooked previously either because of the insufficiently low temperatures used, or due to limitations imposed by polycrystalline samples. For the spin-ice pyrochlores Dy(2)Ti(2)O(7) and Ho(2)Ti(2)O(7), an unusually slow relaxation of the magnetization has been observed in lower fields, while the magnetization process in higher fields is essentially hysteresis-free and does not depend on sample history. For the XY pyrochlore Er(2)Ti(2)O(7), the magnetic susceptibility shows nearly diverging behaviour on approach to a critical field, H(C) = 13.5 kOe, above which the magnetization does not saturate but continues to grow at a significant rate. For the Heisenberg pyrochlore Gd(2)Ti(2)O(7), the magnetic susceptibility shows a pronounced change of slope at both transition temperatures, T(N1) = 1.02 K and T(N2) = 0.74 K, contrary to the earlier reports.

  6. Understanding the Magnetic Susceptibility Measurements by Using an Analytical Scale

    Science.gov (United States)

    Cano, M. E.; Cordova-Fraga, T.; Sosa, M.; Bernal-Alvarado, J.; Baffa, O.

    2008-01-01

    A description of the measurement procedure, related theory and experimental data analysis of the magnetic susceptibility of materials is given. A short review of previous papers in the line of this subject is presented. This work covers the whole experimental process, in detail, and presents a pragmatic approach for pedagogical sake. (Contains 2…

  7. Simple System to Measure the Earth's Magnetic Field

    Science.gov (United States)

    Akoglu, R.; Halilsoy, M.; Mazharimousavi, S. Habib

    2010-01-01

    Our aim in this proposal is to use Faraday's law of induction as a simple lecture demonstration to measure the Earths magnetic field (B). This will also enable the students to learn about how electric power is generated from rotational motion. Obviously the idea is not original, yet it may be attractive in the sense that no sophisticated devices…

  8. Using Nuclear Magnetic Resonance Spectroscopy for Measuring Ternary Phase Diagrams

    Science.gov (United States)

    Woodworth, Jennifer K.; Terrance, Jacob C.; Hoffmann, Markus M.

    2006-01-01

    A laboratory experiment is presented for the upper-level undergraduate physical chemistry curriculum in which the ternary phase diagram of water, 1-propanol and n-heptane is measured using proton nuclear magnetic resonance (NMR) spectroscopy. The experiment builds upon basic concepts of NMR spectral analysis, typically taught in the undergraduate…

  9. Magnetic moment measurement of β-emitter 12N

    Institute of Scientific and Technical Information of China (English)

    ZHENGYong-nan; ZHOUDong-mei; DUEn-peng; YUANDa-qing; ZUOYi; WANGZhi-qiang; LUOHai-long; M.Mihara; M.Fukuda; K.Matsuta; T.Minamisono; ZHUSheng-yun

    2003-01-01

    The magnetic moment of 12N(Iπ= +, T /2=11 ms) has been measured by the β-NMR method. The experiment was performed with the β-NMR and β-NQR facilities at the 5 MV Van de Graaff accelerator at Osaka University, Japan.

  10. Torque measurements on ferrofluid cylinders in rotating magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Rinaldi, Carlos [Department of Chemical Engineering, University of Puerto Rico, PO Box 9046, Mayagueez, PR 00680 (United States)]. E-mail: crinaldi@uprm.edu; Gutman, Fernando [Department of Chemical Engineering, University of Puerto Rico, PO Box 9046, Mayagueez, PR 00680 (United States); He Xiaowei [Laboratory for Electromagnetic and Electronic Systems, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139 (United States); Rosenthal, Adam D. [Laboratory for Electromagnetic and Electronic Systems, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139 (United States); Zahn, Markus [Laboratory for Electromagnetic and Electronic Systems, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139 (United States)

    2005-03-15

    We study the response of magnetic nanoparticle suspensions (ferrofluids) to uniform rotating magnetic fields generated by a two-pole three-phase magnetic induction motor stator winding. Measurements of the torque required to rotate a polycarbonate spindle submerged in ferrofluid subjected to co-rotating and counter-rotating fields yield experimental observations of negative magnetoviscosity in a cylindrical Couette geometry, conceptually similar to the observations of Bacri et al. (Phys. Rev. Lett. 75 (1995) 2128) in a Poiseuille flow under an oscillating magnetic field. Further measurements are presented for the torque required to restrain a spindle when it is (i) entirely filled with ferrofluid (ii) entirely surrounded with ferrofluid, and (iii) both entirely filled and surrounded with ferrofluid. Some of the results for the spindle either entirely filled or entirely surrounded with ferrofluid are compared to theoretical expressions obtained from the ferrohydrodynamic equations using a rigorous regular perturbation expansion in the small parameter {omega}{tau}, where {omega} is the applied field frequency and {tau} is the effective magnetic relaxation time of the suspension.

  11. Dynamic material strength measurement utilizing magnetically applied pressure-shear

    Directory of Open Access Journals (Sweden)

    Alexander C.S.

    2012-08-01

    Full Text Available Magnetically applied pressure-shear (MAPS is a recently developed technique used to measure dynamic material strength developed at Sandia National Laboratories utilizing magneto-hydrodynamic (MHD drive pulsed power systems. MHD drive platforms generate high pressures by passing a large current through a pair of parallel plate conductors which, in essence, form a single turn magnet coil. Lorentz forces resulting from the interaction of the self-generated magnetic field and the drive current repel the plates and result in a high pressure ramp wave propagating in the conductors. This is the principle by which the Sandia Z Machine operates for dynamic material testing. MAPS relies on the addition of a second, external magnetic field applied orthogonally to both the drive current and the self-generated magnetic field. The interaction of the drive current and this external field results in a shear wave being induced directly in the conductors. Thus both longitudinal and shear stresses are generated. These stresses are coupled to a sample material of interest where shear strength is probed by determining the maximum transmissible shear stress in the state defined by the longitudinal compression. Both longitudinal and transverse velocities are measured via a specialized velocity interferometer system for any reflector (VISAR. Pressure and shear strength of the sample are calculated directly from the VISAR data. Results of tests on several materials at modest pressures (∼10GPa will be presented and discussed.

  12. Measurements of stellar magnetic fields with the autocorrelation of spectra

    CERN Document Server

    Borra, Ermanno F

    2015-01-01

    We present a novel technique that uses the autocorrelation of the spectrum of a star to measure the line broadening caused by the modulus of its average surface magnetic field. The advantage of the autocorrelation comes from the fact that it can detect very small spectral line broadening effects because it averages over many spectral lines and therefore gives an average with a very high signal to noise ratio. We validate the technique with the spectra of known magnetic stars and obtain autocorrelation curves that are in full agreement with published magnetic curves obtained with Zeeman splitting. The autocorrelation also gives less noisy curves so that it can be used to obtain very accurate curves. We degrade the resolution of spectra of these magnetic stars to lower spectral resolutions where the Zeeman splitting is undetectable. At these resolutions, the autocorrelation still gives good quality curves, thereby showing that it can be used to measure magnetic fields in spectra where the Zeeman splitting is si...

  13. Vortex magnetic structure in circularly magnetized microwires as deduced from magneto-optical Kerr measurements

    KAUST Repository

    Ivanov, Yurii P.

    2014-02-14

    The magneto-optic Kerr effect has been employed to determine the magnetization process and estimate the domain structure of microwires with circular magnetic anisotropy. The diameter of microwires was 8 μm, and pieces 2 cm long were selected for measurements. The analysis of the local surface longitudinal and transverse hysteresis loops has allowed us to deduce a vortex magnetic structure with axial core and circular external shell. Moreover, a bamboo-like surface domain structure is confirmed with wave length of around 10 to 15 μm and alternating chirality in adjacent circular domains. The width of the domain wall is estimated to be less than 3 μm. Finally, closure domain structures with significant helical magnetization component are observed extending up to around 1000 μm from the end of the microwire.

  14. Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods

    Energy Technology Data Exchange (ETDEWEB)

    Keating, Kristina [Rutgers Univ., Newark, NJ (United States). Dept. of Earth and Environmental Sciences; Slater, Lee [Rutgers Univ., Newark, NJ (United States). Dept. of Earth and Environmental Sciences; Ntarlagiannis, Dimitris [Rutgers Univ., Newark, NJ (United States). Dept. of Earth and Environmental Sciences; Williams, Kenneth H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division

    2015-02-24

    This documents contains the final report for the project "Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods" (DE-SC0007049) Executive Summary: Our research aimed to develop borehole measurement techniques capable of monitoring subsurface processes, such as changes in pore geometry and iron/sulfur geochemistry, associated with remediation of heavy metals and radionuclides. Previous work has demonstrated that geophysical method spectral induced polarization (SIP) can be used to assess subsurface contaminant remediation; however, SIP signals can be generated from multiple sources limiting their interpretation value. Integrating multiple geophysical methods, such as nuclear magnetic resonance (NMR) and magnetic susceptibility (MS), with SIP, could reduce the ambiguity of interpretation that might result from a single method. Our research efforts entails combining measurements from these methods, each sensitive to different mineral forms and/or mineral-fluid interfaces, providing better constraints on changes in subsurface biogeochemical processes and pore geometries significantly improving our understanding of processes impacting contaminant remediation. The Rifle Integrated Field Research Challenge (IFRC) site was used as a test location for our measurements. The Rifle IFRC site is located at a former uranium ore-processing facility in Rifle, Colorado. Leachate from spent mill tailings has resulted in residual uranium contamination of both groundwater and sediments within the local aquifer. Studies at the site include an ongoing acetate amendment strategy, native microbial populations are stimulated by introduction of carbon intended to alter redox conditions and immobilize uranium. To test the geophysical methods in the field, NMR and MS logging measurements were collected before, during, and after acetate amendment. Next, laboratory NMR, MS, and SIP measurements

  15. Measuring and modeling the magnetic settling of superparamagnetic nanoparticle dispersions.

    Science.gov (United States)

    Prigiobbe, Valentina; Ko, Saebom; Huh, Chun; Bryant, Steven L

    2015-06-01

    In this paper, we present settling experiments and mathematical modeling to study the magnetic separation of superparamagnetic iron-oxide nanoparticles (SPIONs) from a brine. The experiments were performed using SPIONs suspensions of concentration between 3 and 202g/L dispersed in water and separated from the liquid under the effect of a permanent magnet. A 1D model was developed in the framework of the sedimentation theory with a conservation law for SPIONs and a mass flux function based on the Newton's law for motion in a magnetic field. The model describes both the hindering effect of suspension concentration (n) during settling due to particle collisions and the increase in settling rate due to the attraction of the SPIONs towards the magnet. The flux function was derived from the settling experiments and the numerical model validated against the analytical solution and the experimental data. Suspensions of SPIONs were of 2.8cm initial height, placed on a magnet, and monitored continuously with a digital camera. Applying a magnetic field of 0.5T of polarization, the SPION's velocity was of approximately 3·10(-5)m/s close to the magnet and decreases of two orders of magnitude across the domain. The process was characterized initially by a classical sedimentation behavior, i.e., an upper interface between the clear water and the suspension slowly moving towards the magnet and a lower interface between the sediment layer and the suspension moving away from the magnet. Subsequently, a rapid separation of nanoparticle occured suggesting a non-classical settling phenomenon induced by magnetic forces which favor particle aggregation and therefore faster settling. The rate of settling decreased with n and an optimal condition for fast separation was found for an initial n of 120g/L. The model agrees well with the measurements in the early stage of the settling, but it fails to describe the upper interface movement during the later stage, probably because of particle

  16. Magnetic vortex chirality determination via local hysteresis loops measurements with magnetic force microscopy.

    Science.gov (United States)

    Coïsson, Marco; Barrera, Gabriele; Celegato, Federica; Manzin, Alessandra; Vinai, Franco; Tiberto, Paola

    2016-07-18

    Magnetic vortex chirality in patterned square dots has been investigated by means of a field-dependent magnetic force microscopy technique that allows to measure local hysteresis loops. The chirality affects the two loop branches independently, giving rise to curves that have different shapes and symmetries as a function of the details of the magnetisation reversal process in the square dot, that is studied both experimentally and through micromagnetic simulations. The tip-sample interaction is taken into account numerically, and exploited experimentally, to influence the side of the square where nucleation of the vortex preferably occurs, therefore providing a way to both measure and drive chirality with the present technique.

  17. Measuring cosmic magnetic fields by rotation measure-galaxy cross-correlations in cosmological simulations

    CERN Document Server

    Stasyszyn, F; Dolag, K; Beck, R; Donnert, J

    2010-01-01

    Using cosmological MHD simulations of the magnetic field in galaxy clusters and filaments we evaluate the possibility to infer the magnetic field strength in filaments by measuring cross-correlation functions between Faraday Rotation Measures (RM) and the galaxy density field. We also test the reliability of recent estimates considering the problem of data quality and Galactic foreground (GF) removal in current datasets. Besides the two self-consistent simulations of cosmological magnetic fields based on primordial seed fields and galactic outflows analyzed here, we also explore a larger range of models scaling up the resulting magnetic fields of one of the simulations. We find that, if an unnormalized estimator for the cross-correlation functions and a GF removal procedure is used, the detectability of the cosmological signal is only possible for future instruments (e.g. SKA and ASKAP). However, mapping of the observed RM signal to the underlying magnetization of the Universe (both in space and time) is an e...

  18. The magnetic recoil spectrometer (MRSt) for time-resolved measurements of the neutron spectrum at the National Ignition Facility (NIF).

    Science.gov (United States)

    Frenje, J A; Hilsabeck, T J; Wink, C W; Bell, P; Bionta, R; Cerjan, C; Gatu Johnson, M; Kilkenny, J D; Li, C K; Séguin, F H; Petrasso, R D

    2016-11-01

    The next-generation magnetic recoil spectrometer for time-resolved measurements of the neutron spectrum has been conceptually designed for the National Ignition Facility. This spectrometer, called MRSt, represents a paradigm shift in our thinking about neutron spectrometry for inertial confinement fusion applications, as it will provide simultaneously information about the burn history and time evolution of areal density (ρR), apparent ion temperature (Ti), yield (Yn), and macroscopic flows during burn. From this type of data, an assessment of the evolution of the fuel assembly, hotspot, and alpha heating can be made. According to simulations, the MRSt will provide accurate data with a time resolution of ∼20 ps and energy resolution of ∼100 keV for total neutron yields above ∼10(16). At lower yields, the diagnostic will be operated at a higher-efficiency, lower-energy-resolution mode to provide a time resolution of ∼20 ps.

  19. The magnetic recoil spectrometer (MRSt) for time-resolved measurements of the neutron spectrum at the National Ignition Facility (NIF)

    Science.gov (United States)

    Frenje, J. A.; Hilsabeck, T. J.; Wink, C. W.; Bell, P.; Bionta, R.; Cerjan, C.; Gatu Johnson, M.; Kilkenny, J. D.; Li, C. K.; Séguin, F. H.; Petrasso, R. D.

    2016-11-01

    The next-generation magnetic recoil spectrometer for time-resolved measurements of the neutron spectrum has been conceptually designed for the National Ignition Facility. This spectrometer, called MRSt, represents a paradigm shift in our thinking about neutron spectrometry for inertial confinement fusion applications, as it will provide simultaneously information about the burn history and time evolution of areal density (ρR), apparent ion temperature (Ti), yield (Yn), and macroscopic flows during burn. From this type of data, an assessment of the evolution of the fuel assembly, hotspot, and alpha heating can be made. According to simulations, the MRSt will provide accurate data with a time resolution of ˜20 ps and energy resolution of ˜100 keV for total neutron yields above ˜1016. At lower yields, the diagnostic will be operated at a higher-efficiency, lower-energy-resolution mode to provide a time resolution of ˜20 ps.

  20. The magnetic recoil spectrometer (MRSt) for time-resolved measurements of the neutron spectrum at the National Ignition Facility (NIF)

    Energy Technology Data Exchange (ETDEWEB)

    Frenje, J. A., E-mail: jfrenje@psfc.mit.edu; Wink, C. W.; Gatu Johnson, M.; Li, C. K.; Séguin, F. H.; Petrasso, R. D. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hilsabeck, T. J.; Kilkenny, J. D. [General Atomics, San Diego, California 92186 (United States); Bell, P.; Bionta, R.; Cerjan, C. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-11-15

    The next-generation magnetic recoil spectrometer for time-resolved measurements of the neutron spectrum has been conceptually designed for the National Ignition Facility. This spectrometer, called MRSt, represents a paradigm shift in our thinking about neutron spectrometry for inertial confinement fusion applications, as it will provide simultaneously information about the burn history and time evolution of areal density (ρR), apparent ion temperature (T{sub i}), yield (Y{sub n}), and macroscopic flows during burn. From this type of data, an assessment of the evolution of the fuel assembly, hotspot, and alpha heating can be made. According to simulations, the MRSt will provide accurate data with a time resolution of ∼20 ps and energy resolution of ∼100 keV for total neutron yields above ∼10{sup 16}. At lower yields, the diagnostic will be operated at a higher-efficiency, lower-energy-resolution mode to provide a time resolution of ∼20 ps.

  1. Measurement of hadronic shower punchthrough in magnetic field

    CERN Document Server

    Albajar, C; Arefev, A; Bacci, Cesare; Bencze, G L; Bergman, R; Bizzeti, A; Brouwer, C; Cardarelli, R; Casoli, P; Centro, Sandro; Ceradini, F; Choumilov, E; Chrisman, D; Ciapetti, G; Civinini, C; Cline, D; D'Alessandro, R; Della Negra, Michel; Dénes, E; Di Ciaccio, Anna; Dominik, Wojciech; Faissner, Helmut; Ferrando, A; Fouz-Iglesias, M C; Gorn, W; Górski, M; Hervé, A; Iglesias, A; Juntunen, M; Karimäki, V; Kinnunen, Ritva; Kluge, A; Kolotaev, Yu; Konecki, M; König, A C; Kólikowski, J; Lacava, F; Layter, J G; Le Coultre, P; Lyndon, C; Malinin, A; Margutti, G; Martinelli, R; Martínez-Laso, L; McNeil, R R; Meneguzzo, Anna Teresa; Meschini, M; Moers, T; Mohammadi-Baarmand, M; Nisati, A; Orestano, D; Österberg, K; Otwinowski, S; Petrolo, E; Pimiä, M; Pozhidaev, V; Pols, C L A; Pontecorvo, L; Porth, Paul; Radermacher, E; Razen, B; Reithler, H; Ribeiro, R; Rojkov, A; Sanjari, A H; Santonico, R; Sartori, P; Shank, J T; Schwarthoff, H; Seez, Christopher J; Shen, B C; Szeptycka, M; Szoncsó, F; Teykal, H F; Tolsma, H; Tuchscherer, H; Tuominiemi, Jorma; Tuuva, T; van der Graaf, H; Veneziano, Stefano; Verzocchi, M; Vesztergombi, G; Wagner, H; Walzel, G; Wijnen, T A M; Wilson, G W; Wrochna, G; Wulz, Claudia Elisabeth; Zanello, L; Zotto, P L

    1996-01-01

    The total punchthrough probability of showers produced by negative pions, positive pions, positive kaons and protons, has been measured as a function of depth in an absorber in a magnetic field ranging from 0 to 3 Tesla. The incident particle momentum varied from 10 to 300 GeV/c. The lateral shower development and particle multiplicity at several absorber depths have been determined. The measurements are compared with the predictions of Monte Carlo simulation programs.

  2. Measurement of magnetic fluctuation-induced particle flux (invited).

    Science.gov (United States)

    Ding, W X; Brower, D L; Yates, T Y

    2008-10-01

    Magnetic field fluctuation-induced particle transport has been directly measured in the high-temperature core of the MST reversed field pinch plasma. Measurement of radial particle transport is achieved by combining various interferometry techniques, including Faraday rotation, conventional interferometry, and differential interferometry. It is observed that electron convective particle flux and its divergence exhibit a significant increase during a sawtooth crash. In this paper, we describe the basic techniques employed to determine the particle flux.

  3. Flux Loop Measurements of the Magnetic Flux Density in the CMS Magnet Yoke

    CERN Document Server

    Klyukhin, V I; Ball, A.; Curé, B.; Gaddi, A.; Gerwig, H.; Mulders, M.; Hervé, A.; Loveless, R.

    2016-01-01

    The Compact Muon Solenoid (CMS) is a general purpose detector, designed to run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its distinctive features include a 4 T superconducting solenoid with 6-m-diameter by 12.5-m-length free bore, enclosed inside a 10,000-ton return yoke made of construction steel. The return yoke consists of five dodecagonal three-layered barrel wheels and four end-cap disks at each end comprised of steel blocks up to 620 mm thick, which serve as the absorber plates of the muon detection system. To measure the field in and around the steel, a system of 22 flux loops and 82 3-D Hall sensors is installed on the return yoke blocks. A TOSCA 3-D model of the CMS magnet is developed to describe the magnetic field everywhere outside the tracking volume measured with the field-mapping machine. The first attempt is made to measure the magnetic flux density in the steel blocks of the CMS magnet yoke using the standard magnet discharge with the current ramp down speed of 1.5 A/...

  4. Spin/orbital and magnetic quantum number selective magnetization measurements for CoFeB/MgO multilayer films

    Science.gov (United States)

    Yamazoe, M.; Kato, T.; Suzuki, K.; Adachi, M.; Shibayama, A.; Hoshi, K.; Itou, M.; Tsuji, N.; Sakurai, Y.; Sakurai, H.

    2016-11-01

    Spin selective magnetic hysteresis (SSMH) curves, orbital selective magnetic hysteresis (OSMH) curves and magnetic quantum number selective SSMH curves are obtained for CoFeB/MgO multilayer films by combining magnetic Compton profile measurements and superconducting quantum interference device (SQUID) magnetometer measurements. Although the SQUID magnetometer measurements do not show perpendicular magnetic anisotropy (PMA) in the CoFeB/MgO multilayer film, PMA behavior is observed in the OSMH and SSMH curves for the |m|  =  2 magnetic quantum number states. These facts indicate that magnetization switching behavior is dominated by the orbital magnetization of the |m|  =  2 magnetic quantum number states.

  5. An in-plane magnetic chiral dichroism approach for measurement of intrinsic magnetic signals using transmitted electrons.

    Science.gov (United States)

    Song, Dongsheng; Tavabi, Amir H; Li, Zi-An; Kovács, András; Rusz, Ján; Huang, Wenting; Richter, Gunther; Dunin-Borkowski, Rafal E; Zhu, Jing

    2017-05-15

    Electron energy-loss magnetic chiral dichroism is a powerful technique that allows the local magnetic properties of materials to be measured quantitatively with close-to-atomic spatial resolution and element specificity in the transmission electron microscope. Until now, the technique has been restricted to measurements of the magnetic circular dichroism signal in the electron beam direction. However, the intrinsic magnetization directions of thin samples are often oriented in the specimen plane, especially when they are examined in magnetic-field-free conditions in the transmission electron microscope. Here, we introduce an approach that allows in-plane magnetic signals to be measured using electron magnetic chiral dichroism by selecting a specific diffraction geometry. We compare experimental results recorded from a cobalt nanoplate with simulations to demonstrate that an electron magnetic chiral dichroism signal originating from in-plane magnetization can be detected successfully.

  6. In situ measurements of magnetic nanoparticles after placenta perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Müller, Robert, E-mail: robert.mueller@ipht-jena.de [Leibniz-Institute of Photonic Technology (IPHT), Jena (Germany); Gläser, Marcus [Leibniz-Institute of Photonic Technology (IPHT), Jena (Germany); University of Applied Sciences, Jena (Germany); Göhner, Claudia; Seyfarth, Lydia; Schleussner, Ekkehard [Department of Obstetrics and Gynecology, Jena University Hospital (Germany); Hofmann, Andreas [HTS Systeme GmbH, Wallenfels (Germany); Fritzsche, Wolfgang [Leibniz-Institute of Photonic Technology (IPHT), Jena (Germany)

    2015-04-15

    Nanoparticles (NP) present promising tools for medical applications. However, the investigation of their spatial and temporal distribution is hampered by missing in-situ particle detection and quantification technologies. The placenta perfusion experiment represents an interesting model for the study of the particle distribution at a biological barrier. It allows the ex-vivo investigation of the permeability of the placenta for materials of interest. We introduce an approach based on a magnetic system for an in situ measurement of the concentration of magnetic NPs in such an experiment. A previously off-line utilized magnetic readout device (sensitivity of ≈10{sup −8} Am{sup 2}) was used for long term measurements of magnetic NP of 100–150 nm size range in a closed circuit of a placenta perfusion. It represents a semiquantitative approach. The behavior of particles in the placenta and in the measurement system was studied, as well as the influence of particle surface modifications. The results suggest a transfer of a low amount of particles from the maternal to the fetal blood circuit.

  7. In situ measurements of magnetic nanoparticles after placenta perfusion

    Science.gov (United States)

    Müller, Robert; Gläser, Marcus; Göhner, Claudia; Seyfarth, Lydia; Schleussner, Ekkehard; Hofmann, Andreas; Fritzsche, Wolfgang

    2015-04-01

    Nanoparticles (NP) present promising tools for medical applications. However, the investigation of their spatial and temporal distribution is hampered by missing in-situ particle detection and quantification technologies. The placenta perfusion experiment represents an interesting model for the study of the particle distribution at a biological barrier. It allows the ex-vivo investigation of the permeability of the placenta for materials of interest. We introduce an approach based on a magnetic system for an in situ measurement of the concentration of magnetic NPs in such an experiment. A previously off-line utilized magnetic readout device (sensitivity of ≈10-8 Am2) was used for long term measurements of magnetic NP of 100-150 nm size range in a closed circuit of a placenta perfusion. It represents a semiquantitative approach. The behavior of particles in the placenta and in the measurement system was studied, as well as the influence of particle surface modifications. The results suggest a transfer of a low amount of particles from the maternal to the fetal blood circuit.

  8. Internal Magnetic Field, Temperature and Density Measurements on Magnetized HED plasmas using Pulsed Polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Roger J. [Univ. of Washington, Seattle, WA (United States)

    2016-10-20

    The goals were to collaborate with the MSX project and make the MSX platform reliable with a performance where pulsed polarimetry would be capable of adding a useful measurement and then to achieve a first measurement using pulsed polarimetry. The MSX platform (outside of laser blow off plasmas adjacent to magnetic fields which are low beta) is the only device that can generate high beta magnetized collisionless supercritical shocks, and with a large spatial size of ~10 cm. Creating shocks at high Mach numbers and investigating the dynamics of the shocks was the main goal of the project. The MSX shocks scale to astrophysical magnetized shocks and potentially throw light on the generation of highly energetic particles via a mechanism like the Fermi process.

  9. Sensitivity analysis of magnetic field measurements for magnetic resonance electrical impedance tomography (MREIT)

    DEFF Research Database (Denmark)

    Göksu, Cihan; Scheffler, Klaus; Ehses, Philipp

    2017-01-01

    : The efficiency simulations and experimental results are in good agreement. When using optimal parameters, ΔBz,c can be reliably measured in the phantom even at injected current strengths of 1 mA or lower for both sequence types. The importance of using proper crusher gradient selection on the phase evolution...... in a MESE experiment is also demonstrated. CONCLUSION: The efficiencies observed with the optimized sequence parameters will likely render in-vivo human brain MREIT feasible. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine.......PURPOSE: Clinical use of magnetic resonance electrical impedance tomography (MREIT) still requires significant sensitivity improvements. Here, the measurement of the current-induced magnetic field (ΔBz,c ) is improved using systematic efficiency analyses and optimization of multi-echo spin echo...

  10. Validation of magnetic resonance concentration measurements with adiabatic wall temperature measurements

    Science.gov (United States)

    Sayles, Emily L.; Eaton, John K.

    2016-12-01

    Adiabatic wall temperature measurements were obtained in a high subsonic Mach number airflow experiment and compared with concentration measurements near the surface from a low-speed liquid flow experiment. Excellent agreement between the temperature and concentration measurements validates the investigation of turbulent mixing phenomena in compressible gas flows through the study of incompressible liquid flows with magnetic resonance techniques.

  11. Magnetopause Reconnection Impact Parameters from Multiple Spacecraft Magnetic Field Measurements

    Science.gov (United States)

    Wendel, Deirdre E.; Reiff, Patricia H.

    2009-01-01

    We present a novel technique that exploits multiple spacecraft data to determine the impact parameters of the most general form of magnetic reconnection at the magnetopause. The method consists of a superposed epoch of multiple spacecraft magnetometer measurements that yields the instantaneous magnetic spatial gradients near a magnetopause reconnection site. The gradients establish the instantaneous positions of the spacecraft relative to the reconnection site. The analysis is well suited to evaluating the spatial scales of singular field line reconnection, which is characterized by a two-dimensional x-type topology adjacent and perpendicular to a reconnecting singular field line. Application of the method to Cluster data known to lie in the vicinity of a northward IMF reconnection site establishes a field topology consistent with singular field line reconnection and a normal magnetic field component of 20 nT. The corresponding current structure consists of a 130 km sheet possibly embedding a thinner. bifurcated sheet.

  12. Measurement of the inductance of resistive magnets: two case studies

    CERN Document Server

    Buzio, M; Giloteaux, D

    2011-01-01

    This note concerns the main definitions of self-inductance (i.e. differential, secant and energy-based) that are relevant for the electromagnetic modelling of accelerator magnets. In particular, we consider the case of iron-dominated resistive magnets. The different definitions, which coincide in the linear limit at low field, tend to diverge dramatically as the iron becomes saturated. We describe the measurement technique and the results for two case studies, i.e. the PS MTE octupole and a main SPS dipole of MBB type. We show that the differential inductance may drop dramatically at high current, up to about a factor two, even for magnets where the field non linearity is within a few percent only.

  13. Project Vanguard Magnetic-Field Instrumentation and Measurements

    Science.gov (United States)

    Heppner, J. P.; Storarik, J. D.; Shapiro, I. R.; Cain, J. C.

    1960-01-01

    The Vanguard III Satellite, 1959 Eta, placed in orbit on September 18, 1959, contained a proton precessional magnetometer for magnetic-field studies of exceptional accuracy. Throughout the 85 days of battery life, the instrumentation functioned according to plan. Measurements of the absolute total field were obtained in the meridian belts of Minitrack stations at altitudes 510 to 3750 kilometers and at latitudes +/- 33.4 degrees. Surface magnetic observatories were operated at eight of the Minitrack stations to furnish correlative information. This paper reviews briefly the instrumentation employed in these experiments, and the data collection and reduction procedures. Emphasis is given to results from a preliminary analysis. Specifically, this analysis bears on the accuracy of computed fields, the stability of the earth's field in space, the Capetown anomaly, and magnetic-storm effects.

  14. Generation and measurement of pulsed high magnetic field

    CERN Document Server

    Jana, S

    2000-01-01

    Pulsed magnetic field has been generated by discharging a capacitor bank through a 5-layer air-core solenoid. The strength of the magnetic field at its peak has been measured using the voltage induced in various pick-up coils, and also from the Zeeman splitting of an ion having a known g value. Synchronizing a xenon flash at the peak of the magnetic field, this lab-made instrument has been made well suited to study the Zeeman effect, etc. at a temperature of 25 K. As an application of this setup, we have investigated the Zeeman splitting of the sup 4 I sub 9 sub / sub 2-> sup 4 G sub 5 sub / sub 2 transition of the Nd sup 3 sup + -doped CsCdCl sub 3 crystal at 7.8 T, and determined the splitting factors.

  15. The BOES spectropolarimeter for Zeeman measurements of stellar magnetic fields

    CERN Document Server

    Kim, Kang-Min; Valyavin, Gennady G; Plachinda, Sergei; Jang, Jeong Gyun; Jang, Be-Ho; Seong, Hyeon Cheol; Lee, Byeong-Cheol; Kang, Dong-Il; Park, Byeong-Gon; Yoon, Tae Seog; Vogt, Steven S

    2007-01-01

    We introduce a new polarimeter installed on the high-resolution fiber-fed echelle spectrograph (called BOES) of the 1.8-m telescope at the Bohyunsan Optical Astronomy Observatory, Korea. The instrument is intended to measure stellar magnetic fields with high-resolution (R $\\sim$ 60000) spectropolarimetric observations of intrinsic polarization in spectral lines. In this paper we describe the spectropolarimeter and present test observations of the longitudinal magnetic fields in some well-studied F-B main sequence magnetic stars (m_v < 8.8^m). The results demonstrate that the instrument has a high precision ability of detecting the fields of these stars with typical accuracies ranged from about 2G to a few tens of gauss.

  16. Mars Environment and Magnetic Orbiter Scientific and Measurement Objectives

    DEFF Research Database (Denmark)

    Leblanc, F.; Langlais, B.; Fouchet, T.

    2009-01-01

    In this paper, we summarize our present understanding of Mars' atmosphere, magnetic field, and surface and address past evolution of these features. Key scientific questions concerning Mars' surface, atmosphere, and magnetic field, along with the planet's interaction with solar wind, are discussed....... We also define what key parameters and measurements should be performed and the main characteristics of a martian mission that would help to provide answers to these questions. Such a mission-Mars Environment and Magnetic Orbiter (MEMO)-was proposed as an answer to the Cosmic Vision Call...... of Opportunity as an M-class mission (corresponding to a total European Space Agency cost of less than 300 M(sic)). MEMO was designed to study the strong interconnection between the planetary interior, atmosphere, and solar conditions, which is essential to our understanding of planetary evolution...

  17. Embedded north-seeker for automatic absolute magnetic DI measurements

    Science.gov (United States)

    Gonsette, Alexandre; Rasson, Jean

    2014-05-01

    In magnetic observatory Earth magnetic field is recorded with a resolution of 0.1nT for 1min sampling (new standards impose 1pT for 1s sampling). The method universally adopted for measuring it is a combination of three instruments. Vectorial magnetometer (variometer) records variations of the three components around a reference value or a baseline. A proton or an overhauser magnetometer is an absolute instrument able to measure the modulus of the field and used to determine the F component baseline of the variometer. The declination and inclination baselines require a manual procedure to be computed. An operator manipulates a non-magnetic theodolite (also called a DIFlux) to measure the D and I angles in different configurations with a resolution of a few arcsec. The AutoDIF is a non-magnetic automatic DIFlux using the same protocol as the manual procedure. The declination defined according to the true north is determined by means of a target pointing system. Even if the technique is fast and accurate, it becomes problematic in case of unmanned deployment. In particular the area between the target and the DIFlux is out of control. Snow storm, fog, vegetation or condensation on windows are examples of perturbation preventing for finding the target. It is obvious in case of (future) seafloor observatories. A FOG based north-seeker has been implemented and mounted on the AutoDIF. The first results using a low cost gyro don't meet the Intermagnet specifications yet but are however hopeful. A 0.1° standard deviation has been reached and statistically reduced to 0.01° after less than two days in laboratory. The magnetic disturbance of the sensor is taken into account and compensated by the measurement protocol.

  18. Measurements of Cosmic Magnetism with LOFAR and SKA

    Directory of Open Access Journals (Sweden)

    R. Beck

    2007-06-01

    Full Text Available The origin of magnetic fields in stars, galaxies and clusters is an open problem in astrophysics. The next-generation radio telescopes Low Frequency Array (LOFAR and Square Kilometre Array (SKA will revolutionize the study of cosmic magnetism. "The origin and evolution of cosmic magnetism" is a key science project for SKA. The planned all-sky survey of Faraday rotation measures (RM at 1.4 GHz will be used to model the structure and strength of the magnetic fields in the intergalactic medium, the interstellar medium of intervening galaxies, and in the Milky Way. A complementary survey of selected regions at around 200 MHz is planned as a key project for LOFAR. Spectro-polarimetry applied to the large number of spectral channels available for LOFAR and SKA will allow to separate RM components from distinct foreground and background regions and to perform 3-D Faraday tomography of the interstellar medium of the Milky Way and nearby galaxies. – Deep polarization mapping with LOFAR and SKA will open a new era also in the observation of synchrotron emission from magnetic fields. LOFAR's sensitivity will allow to map the structure of weak, extended magnetic fields in the halos of galaxies, in galaxy clusters, and possibly in the intergalactic medium. Polarization observations with SKA at higher frequencies (1–10 GHz will show the detailed magnetic field structure within the disks and central regions of galaxies, with much higher angular resolution than present-day radio telescopes.

  19. New Limits on Extragalactic Magnetic Fields from Rotation Measures

    Science.gov (United States)

    Pshirkov, M. S.; Tinyakov, P. G.; Urban, F. R.

    2016-05-01

    We take advantage of the wealth of rotation measures data contained in the NRAO VLA Sky Survey catalog to derive new, statistically robust, upper limits on the strength of extragalactic magnetic fields. We simulate the extragalactic magnetic field contribution to the rotation measures for a given field strength and correlation length, by assuming that the electron density follows the distribution of Lyman-α clouds. Based on the observation that rotation measures from distant radio sources do not exhibit any trend with redshift, while the extragalactic contribution instead grows with distance, we constrain fields with Jeans' length coherence length to be below 1.7 nG at the 2 σ level, and fields coherent across the entire observable Universe below 0.65 nG. These limits do not depend on the particular origin of these cosmological fields.

  20. Magnetic Barkhausen noise measurement by resonant coil method

    Energy Technology Data Exchange (ETDEWEB)

    Capo-Sanchez, J. [Departamento de Fisica, Facultad de Ciencias Naturales, Universidad de Oriente, Av. Patricio Lumumba s/n, 90500 Santiago de Cuba (Cuba)], E-mail: jcapo@usp.br; Padovese, L. [Departamento de Engenharia Mecanica, Escola Politecnica, Universidade de Sao Paulo, Av. Prof. Mello Moraes, 2231, 05508-900 Sao Paulo (Brazil)

    2009-09-15

    This paper describes a powerful new technique for nondestructive evaluation of ferromagnetic material. A method has been developed for measuring magnetic Barkhausen signals under different coil resonance frequencies. The measurements allow one to establish the behavior relating the power spectral density maximum and the resonant coil frequency. Time-frequency analysis of Barkhausen signals puts in evidence the tuning regions for each coil, and allows clear identification of each contribution to the Barkhausen signal spectrum. This concept was used in order to evaluate the relation between the degree of plastic deformation in carbon steel samples, and the power spectral density maximum at different resonance frequencies. This result also makes it possible to the selectively modify measurement sensibility to the magnetic Barkhausen signal by using different resonance frequencies.

  1. Measurement and reconstruction of the BEBC magnetic field map

    CERN Document Server

    Häbel, E; Wittgenstein, F

    1973-01-01

    The superconducting magnet of the Big European Bubble Chamber (BEBC) has been excited with currents up to 5035 A corresponding to a magnetic induction of 3.1 Tesla at the center of the chamber. Since one expected that during the charging of the magnet coils long time constant eddy currents would be induced by the varying radial field components, a system of 181 Hall-probes was installed on the boundary of the chamber body allowing to survey the magnetic field map. This Hall-probe system together with an NMR-probe (nuclear magnetic resonance) enabled us to measure and reconstruct to an accuracy of better than 0.1the field map of BEBC, which in itself is uniform to within 3 191332nside the visible fiducial volume of the Chamber. Direct evidence was also given for field map distortions due to the eddy current field which amounted to about 0.723420f the maximum recorded field values at the chamber center. (7 refs).

  2. Measurement and reconstruction of the BEBC magnetic field map

    CERN Document Server

    Häbel, E; Wittgenstein, F

    1973-01-01

    The superconducting magnet of the Big European Bubble Chamber (BEBC) has been excited with currents up to 5035 A corresponding to a magnetic induction of 3.1 Tesla at the center of the chamber. Since one expected that during the charging of the magnet coils long time constant eddy currents would be induced by the varying radial field components, a system of 181 Hall-probes was installed on the boundary of the chamber body allowing to survey the magnetic field map. This Hall-probe system together with an NMR-probe (nuclear magnetic resonance) enabled us to measure and reconstruct to an accuracy of better than 0.1% the field map of BEBC, which in itself is uniform to within 3% inside the visible fiducial volume of the Chamber. Direct evidence was also given for field map distortions due to the eddy current field which amounted to about 0.7% of the maximum recorded field values at the chamber center. (7 refs).

  3. Fundamentals and applications of magnetic materials

    CERN Document Server

    Krishnan, Kannan M

    2016-01-01

    Students and researchers looking for a comprehensive textbook on magnetism, magnetic materials and related applications will find in this book an excellent explanation of the field. Chapters progress logically from the physics of magnetism, to magnetic phenomena in materials, to size and dimensionality effects, to applications. Beginning with a description of magnetic phenomena and measurements on a macroscopic scale, the book then presents discussions of intrinsic and phenomenological concepts of magnetism such as electronic magnetic moments and classical, quantum, and band theories of magnetic behavior. It then covers ordered magnetic materials (emphasizing their structure-sensitive properties) and magnetic phenomena, including magnetic anisotropy, magnetostriction, and magnetic domain structures and dynamics. What follows is a comprehensive description of imaging methods to resolve magnetic microstructures (domains) along with an introduction to micromagnetic modeling. The book then explores in detail size...

  4. Light nuclear charge measurement with Alpha Magnetic Spectrometer Electromagnetic Calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Basara, Laurent [Trento Institute for Fundamental Physics and Applications, Povo 38123 (Italy); Choutko, Vitaly [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Li, Qiang, E-mail: q.li@cern.ch [Harbin Institute of Technology, Harbin, 150001 (China)

    2016-06-11

    The Alpha Magnetic Spectrometer (AMS) is a high energy particle detector installed and operating on board of the International Space Station (ISS) since May 2011. So far more than 70 billion cosmic ray events have been recorded by AMS. In the present paper the Electromagnetic Calorimeter (ECAL) detector of AMS is used to measure cosmic ray nuclear charge magnitudes up to Z=10. The obtained charge magnitude resolution is about 0.1 and 0.3 charge unit for Helium and Carbon, respectively. These measurements are important for an accurate determination of the interaction probabilities of various nuclei with the AMS materials. The ECAL charge calibration and measurement procedures are presented.

  5. MonitoRing - Magnetic induction measurement at your fingertip

    Science.gov (United States)

    Teichmann, D.; Foussier, J.; Löschcke, D.; Leonhardt, S.; Walter, M.

    2013-04-01

    The device presented in this paper is a sensor for monitoring pulse by measuring the bioimpedance of the thumb in an unobtrusive way. The sensor is based on magnetic induction measurement, a non-contact technique for measuring impedance changes of objects [1]. The sensor head of the presented system has the form of a ring and is worn on the finger. The developed technique renders the possibility of easy and unnoticed pulse recording during every day activities without the need for, e.g. electrodes, a pulse belt around the chest, or a pulse photoplethysmographic finger or ear clip.

  6. Measuring and interpretation of three-component borehole magnetic data

    Science.gov (United States)

    Virgil, C.; Ehmann, S.; Hördt, A.; Leven, M.; Steveling, E.

    2012-04-01

    Three-component borehole magnetics provides important additional information compared with total field or horizontal and vertical measurements. The "Göttinger Bohrloch Magnetometer" (GBM) is capable of recording the vector of the magnetic field along with the orientation of the tool using three fluxgate magnetometers and fibre-optic gyros. The GBM was successfully applied in the Outokumpu Deep Drill Hole (OKU R2500), Finland in September 2008 and in the Louisville Seamount Trail (IODP Expedition 330) from December 2010 until February 2011, and in several shallower boreholes. With the declination of the magnetic field, the GBM provides additional information compared to conventional tools, which reduces the ambiguity for structural interpretation. The position of ferromagnetic objects in the vicinity of the borehole can be computed with higher accuracy. In the case of drilled-through structures, three-component borehole magnetics allow the computation of the vector of magnetization. Using supplementary susceptibility data, the natural remanent magnetization (NRM) vector can be derived, which yields information about the apparent polar wander curve and/or about the structural evolution of the rock units. The NRM vector can further be used to reorient core samples in regions of strong magnetization. The most important aspect in three-component borehole magnetics is the knowledge of the orientation of the probe along the drillhole. With the GBM we use three fibre-optic gyros (FOG), which are aligned orthogonal to each other. These instruments record the turning rate about the three main axes of the probe. The FOGs benefit from a high resolution (FOG triplet, temperature dependent drift of the FOGs, misalignment of the fluxgate and FOG triplet in respect with each other, as well as start and end position of the probe with respect to Earth's reference frame. Using the high precision gyro data, we can compute the vector of the magnetic anomaly with respect to the Earth

  7. Macroscopic Theory of Dark Sector

    Directory of Open Access Journals (Sweden)

    Boris E. Meierovich

    2014-01-01

    Full Text Available A simple Lagrangian with squared covariant divergence of a vector field as a kinetic term turned out to be an adequate tool for macroscopic description of the dark sector. The zero-mass field acts as the dark energy. Its energy-momentum tensor is a simple additive to the cosmological constant. Massive fields describe two different forms of dark matter. The space-like massive vector field is attractive. It is responsible for the observed plateau in galaxy rotation curves. The time-like massive field displays repulsive elasticity. In balance with dark energy and ordinary matter it provides a four-parametric diversity of regular solutions of the Einstein equations describing different possible cosmological and oscillating nonsingular scenarios of evolution of the Universe. In particular, the singular big bang turns into a regular inflation-like transition from contraction to expansion with the accelerated expansion at late times. The fine-tuned Friedman-Robertson-Walker singular solution is a particular limiting case at the lower boundary of existence of regular oscillating solutions in the absence of vector fields. The simplicity of the general covariant expression for the energy-momentum tensor allows displaying the main properties of the dark sector analytically. Although the physical nature of dark sector is still unknown, the macroscopic theory can help analyze the role of dark matter in astrophysical phenomena without resorting to artificial model assumptions.

  8. Measurement of the zero-field magnetic dipole moment of magnetizable colloidal silica spheres

    NARCIS (Netherlands)

    Claesson, E.M.; Erne, B.H.; Bakelaar, I.A.; Kuipers, B.W.M.; Philipse, A.P.

    2007-01-01

    The magnetic properties of dispersions of magnetic silica microspheres have been investigated by measuring the magnetization curves and the complex magnetic susceptibility as a function of frequency and field amplitude. The silica spheres appear to have a net permanent magnetic dipole moment, even i

  9. Measurements of Magnetic Helicity within Two Interacting Flux Ropes

    Science.gov (United States)

    Dehaas, Timothy; Gekelman, Walter

    2016-10-01

    Magnetic helicity (HM) has become a useful tool in the exploration of astrophysical plasmas. Its conservation in the MHD limit (and even some fluid approaches) constrains the global behavior of large plasma structures. One such astrophysical structure is a magnetic flux rope: a rope-like, current-carrying plasma embedded in an external magnetic field. Bundles of these ropes are commonly observed extending from the solar surface and can be found in the near-earth environment. In this well-diagnosed experiment (3D measurements of ne, Te, Vp, B, J, E, uflow) , two magnetic flux ropes were generated in the Large Plasma Device at UCLA. These ropes were driven kink-unstable, commencing complex motion. As they interact, helicity conservation is broken in regions of reconnection, turbulence, and instabilities. The changes in helicity can be visualized as 1) the transport of helicity (ϕB +E × A) and 2) the dissipation of the helicity (-2EB). Magnetic helicity is observed to have a negative sign and its counterpart, cross helicity, a positive one. These qualities oscillate 8% peak-to-peak. As the ropes move and the topology of the field lines change, a quasi-separatrix layer (QSL) is formed. The volume averaged HM and the largest value of Q both oscillate but not in phase. In addition to magnetic helicity, similar quantities such as self-helicity, mutual-helicity, vorticity, and canonical helicity are derived and will be presented. This work is supported by LANL-UC research Grant and done at the Basic Plasma Science Facility, which is funded by DOE and NSF.

  10. A Fast Digital Integrator for Magnetic Field Measurements at CERN

    CERN Document Server

    Arpaia, P; Cimmino, P; Giloteaux, D; Masi, A; García-Pérez, J; Spiezia, G; Walckiers, L

    2007-01-01

    A self-calibrating digital instrument for flux measurements on magnets for accelerators used in basic research on subnuclear particles is proposed. The instrument acquires voltage arising from rotating coils transducers with a theoretical resolution of 10 ppt and a maximum sampling frequency of 800 kS/s. Then, samples are integrated on-line and suitably processed in order to improve time resolution and flux accuracy. This allows the limits of state-of-the-art digital fluximeters, related mainly to newgeneration rotating coils, with trigger rate of 20 kHz and coils speed of 10 rps, to be overcome. The instrument has been prototyped at Magnetic Measurement and Testing (MTM) Group of European Laboratory for Nuclear Research (CERN), under a framework of cooperation with the University of Sannio. Details on hardware and firmware conception, as well as on experimental results of the instrument principle validation, and of the preliminary metrological characterization of the prototype, are provided.

  11. Microscopic and macroscopic infarct complicating pediatric epilepsy surgery.

    Science.gov (United States)

    Rubinger, Luc; Hazrati, Lili-Naz; Ahmed, Raheel; Rutka, James; Snead, Carter; Widjaja, Elysa

    2017-03-01

    There is some suggestion that microscopic infarct could be associated with invasive monitoring, but it is unclear if the microscopic infarct is also visible on imaging and associated with neurologic deficits. The aims of this study were to assess the rates of microscopic and macroscopic infarct and other major complications of pediatric epilepsy surgery, and to determine if these complications were higher following invasive monitoring. We reviewed the epilepsy surgery data from a tertiary pediatric center, and collected data on microscopic infarct on histology and macroscopic infarct on postoperative computed tomography (CT) or magnetic resonance imaging (MRI) done one day after surgery and major complications. Three hundred fifty-two patients underwent surgical resection and there was one death. Forty-two percent had invasive monitoring. Thirty patients (9%) had microscopic infarct. Univariable analyses showed that microscopic infarct was higher among patients with invasive monitoring relative to no invasive monitoring (20% vs. 0.5%, respectively, p microscopic infarct had transient right hemiparesis, and two with both macroscopic and microscopic infarct had unexpected persistent neurologic deficits. Thirty-two major complications (9.1%) were reported, with no difference in major complications between invasive monitoring and no invasive monitoring (10% vs. 7%, p = 0.446). In the multivariable analysis, invasive monitoring increased the odds of microscopic infarct (odds ratio [OR] 15.87, p = 0.009), but not macroscopic infarct (OR 2.6, p = 0.173) or major complications (OR 1.4, p = 0.500), after adjusting for age at surgery, sex, age at seizure onset, operative type, and operative location. Microscopic infarct was associated with invasive monitoring, and none of the patients had permanent neurologic deficits. Macroscopic infarct was not associated with invasive monitoring, and two patients with macroscopic infarct had persistent neurologic deficits. Wiley

  12. Low field magnetic measurements on high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, G.; Murphy, S.D.; Li, Z.Y.; Stewart, A.M.; Bhagat, S.M. (Maryland Univ., College Park, MD (USA). Dept. of Physics and Astronomy)

    1989-09-01

    The authors report dc magnetization and ac susceptibility measurements on both micron size powders and sintered samples of several high temperature superconductors. The powder data confirm previous findings that the materials can be treated as conventional superconductors with s-wave pairing. The ac results on sintered slabs ar interpreted using Bean's model and yield the temperature dependence of the shielding current.

  13. Self-consistent magnetic properties of magnetite tracers optimized for magnetic particle imaging measured by ac susceptometry, magnetorelaxometry and magnetic particle spectroscopy

    Science.gov (United States)

    Ludwig, Frank; Remmer, Hilke; Kuhlmann, Christian; Wawrzik, Thilo; Arami, Hamed; Ferguson, R. Mathew; Krishnan, Kannan M.

    2014-06-01

    Sensitivity and spatial resolution in magnetic particle imaging are affected by magnetic properties of the nanoparticle tracers used during imaging. Here, we have carried out a comprehensive magnetic characterization of single-core iron oxide nanoparticles that were designed for MPI. We used ac susceptometry, fluxgate magnetorelaxometry, and magnetic particle spectroscopy to evaluate the tracer's magnetic core size, hydrodynamic size, and magnetic anisotropy. Our results present a self-consistent set of magnetic and structural parameters for the tracers that is consistent with direct measurements of size using transmission electron microscopy and dynamic light scattering and that can be used to better understand their MPI performance.

  14. Self-consistent magnetic properties of magnetite tracers optimized for magnetic particle imaging measured by ac susceptometry, magnetorelaxometry and magnetic particle spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Frank; Remmer, Hilke; Kuhlmann, Christian; Wawrzik, Thilo [Institute of Electrical Measurement and Fundamental Electrical Engineering, TU Braunschweig, Hans-Sommer-Str. 66, D-38106 Braunschweig (Germany); Arami, Hamed; Ferguson, R. Mathew [Department of Materials Science and Engineering Box 352120, University of Washington, Seattle, WA 98195 (United States); Krishnan, Kannan M., E-mail: kannanmk@uw.edu [Department of Materials Science and Engineering Box 352120, University of Washington, Seattle, WA 98195 (United States)

    2014-06-01

    Sensitivity and spatial resolution in magnetic particle imaging are affected by magnetic properties of the nanoparticle tracers used during imaging. Here, we have carried out a comprehensive magnetic characterization of single-core iron oxide nanoparticles that were designed for MPI. We used ac susceptometry, fluxgate magnetorelaxometry, and magnetic particle spectroscopy to evaluate the tracer's magnetic core size, hydrodynamic size, and magnetic anisotropy. Our results present a self-consistent set of magnetic and structural parameters for the tracers that is consistent with direct measurements of size using transmission electron microscopy and dynamic light scattering and that can be used to better understand their MPI performance.

  15. Particle Size-Specific Magnetic Measurements as a Tool for Enhancing Our Understanding of the Bulk Magnetic Properties of Sediments

    Directory of Open Access Journals (Sweden)

    Robert G. Hatfield

    2014-10-01

    Full Text Available Bulk magnetic properties of soils and sediments are often sensitive proxies for environmental change but commonly require interpretation in terms of the different sources of magnetic minerals (or components that combine to generate them. Discrimination of different components in the bulk magnetic record is often attempted through endmember unmixing and/or high resolution measurements that can require intensive measurement plans, assume linear additivity, and sometimes have difficulty in discriminating a large number of sources. As an alternative, magnetic measurements can be made on isolated sediment fractions that constitute the bulk sample. When these types of measurements are taken, heterogeneity is frequently observed between the magnetic properties of different fractions, suggesting different magnetic components often associate with different physical grain sizes. Using a particle size-specific methodology, individual components can be isolated and studied and bulk magnetic properties can be linked to, and isolated from, sedimentological variations. Deconvolving sedimentary and magnetic variability in this way has strong potential for increased understanding of how magnetic fragments are carried in natural systems, how they vary with different source(s, and allows for a better assessment of the effect environmental variability has in driving bulk magnetic properties. However, despite these benefits, very few studies exploit the information they can provide. Here, I present an overview of the different sources of magnetic minerals, why they might associate with different sediment fractions, how bulk magnetic measurements have been used to understand the contribution of different components to the bulk magnetic record, and outline how particle size-specific magnetic measurements can assist in their better understanding. Advantages and disadvantages of this methodology, their role alongside bulk magnetic measurements, and potential future

  16. Measuring Cytokine Concentrations Using Magnetic Spectroscopy of Nanoparticle Brownian Relaxation

    Science.gov (United States)

    Khurshid, Hafsa; Shi, Yipeng; Weaver, John

    The magnetic particle spectroscopy is a newly developed non-invasive technique for obtaining information about the nanoparticles' micro environment. In this technique the nanoparticles' magnetization, induced by an alternating magnetic field at various applied frequencies, is processed to analyze rotational freedom of nanoparticles. By analyzing average rotational freedom, it is possible to measure the nanoparticle's relaxation time, and hence get an estimate of the temperature and viscosity of the medium. In molecular concentration sensing, the rotational freedom indicates the number of nanoparticles that are bound by a selected analyte. We have developed microscopic nanoparticles probes to measure the concentration of selected molecules. The nanoparticles are targeted to bind the selected molecule and the resulting reduction in rotational freedom can be quantified remotely. Previously, sensitivity measurements has been reported to be of the factor of 200. However, with our newer perpendicular field setup (US Patent Application Serial No 61/721,378), it possible to sense cytokine concentrations as low as 5 Pico-Molar in-vitro. The excellent sensitivity of this apparatus is due to isolation of the drive field from the signal so the output can be amplified to a higher level. Dartmouth College.

  17. Domain Specific Language for Magnetic Measurements at CERN

    CERN Document Server

    Petrone, C

    2009-01-01

    CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 20 Member States. Its main purpose is fundamental research in partcle physics, namely investigating what the Universe is made of and how it works. At CERN, the design and realization of the new particle accelerator, the Large Hadron Collider (LHC), has required a remarkable technological effort in many areas of engineering. In particular, the tests of LHC superconducting magnets disclosed new horizons to magnetic measurements. At CERN, the objectively large R&D effort of the Technolgy Department/Magnets, Superconductors and Cryostats (TE/MSC) group identified areas where further work is required in order to assist the LHC commissioning and start-up, to provide continuity in the instrumentation for the LHC magnets maintenance,...

  18. Domain Specific Language for Magnetic Measurements at CERN

    CERN Document Server

    Petrone, C

    2009-01-01

    CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 20 Member States. Its main purpose is fundamental research in partcle physics, namely investigating what the Universe is made of and how it works. At CERN, the design and realization of the new particle accelerator, the Large Hadron Collider (LHC), has required a remarkable technological effort in many areas of engineering. In particular, the tests of LHC superconducting magnets disclosed new horizons to magnetic measurements. At CERN, the objectively large R&D effort of the Technolgy Department/Magnets, Superconductors and Cryostats (TE/MSC) group identified areas where further work is required in order to assist the LHC commissioning and start-up, to provide continuity in the instrumentation for the LHC magnets maintenance,...

  19. New Measure of the Dissipation Region in Collisionless Magnetic Reconnection

    Science.gov (United States)

    Zenitani, Seiji; Hesse, Michael; Klimas, Alex; Kuznetsova, Masha

    2012-01-01

    A new measure to identify a small-scale dissipation region in collisionless magnetic reconnection is proposed. The energy transfer from the electromagnetic field to plasmas in the electron s rest frame is formulated as a Lorentz-invariant scalar quantity. The measure is tested by two-dimensional particle-in-cell simulations in typical configurations: symmetric and asymmetric reconnection, with and without the guide field. The innermost region surrounding the reconnection site is accurately located in all cases. We further discuss implications for nonideal MHD dissipation.

  20. Magnetic sensors for motion measurement of avionic ballscrews

    Directory of Open Access Journals (Sweden)

    E. Cardelli

    2017-05-01

    Full Text Available This paper deals with a theoretical and experimental study about the motion measurement in ballscrews for avionic system. The measurement system is based on a magnetic sensor optimized by a suitable finite element analysis. In particular the sensor performances are simulated for different configurations in order to maximize the sensitivity. The efficiency and the reliability of the optimal configuration found have been validated by means of a dedicated experiment for the simulation of the operative mode of the ballscrews in the avionic environment.

  1. Macroscopically-Discrete Quantum Cosmology

    CERN Document Server

    Chew, Geoffrey F

    2008-01-01

    To Milne's Lorentz-group-based spacetime and Gelfand-Naimark unitary representations of this group we associate a Fock space of 'cosmological preons'-quantum-theoretic universe constituents. Milne's 'cosmological principle' relies on Lorentz invariance of 'age'--global time. We divide Milne's spacetime into 'slices' of fixed macroscopic width in age, with 'cosmological rays' defined on (hyperbolic) slice boundaries-Fock space attaching only to these exceptional universe ages. Each (fixed-age) preon locates within a 6-dimensional manifold, one of whose 3 'extra' dimensions associates in Dirac sense to a self-adjoint operator that represents preon (continuous) local time, the operator canonically-conjugate thereto representing preon (total) energy. Self-adjoint-operator expectations at any spacetime-slice boundary prescribe throughout the following slice a non-fluctuating 'mundane reality'- electromagnetic and gravitational potentials 'tethered' to current densities of locally-conserved electric charge and ener...

  2. Seismic scanning tunneling macroscope - Theory

    KAUST Repository

    Schuster, Gerard T.

    2012-09-01

    We propose a seismic scanning tunneling macroscope (SSTM) that can detect the presence of sub-wavelength scatterers in the near-field of either the source or the receivers. Analytic formulas for the time reverse mirror (TRM) profile associated with a single scatterer model show that the spatial resolution limit to be, unlike the Abbe limit of λ/2, independent of wavelength and linearly proportional to the source-scatterer separation as long as the point scatterer is in the near-field region; if the sub-wavelength scatterer is a spherical impedance discontinuity then the resolution will also be limited by the radius of the sphere. Therefore, superresolution imaging can be achieved as the scatterer approaches the source. This is analogous to an optical scanning tunneling microscope that has sub-wavelength resolution. Scaled to seismic frequencies, it is theoretically possible to extract 100 Hz information from 20 Hz data by imaging of near-field seismic energy.

  3. A magnetic coupling thrust stand for microthrust measurements

    Science.gov (United States)

    Wright, W. P.; Ferrer, P.

    2016-01-01

    A direct thrust measurement system that is based on a horizontal lever and utilizes a novel magnetic coupling mechanism to measure thrust has been developed. The system is capable of measuring thrusts as low as 10’s of μN. While zero drift is observed in the balance, tests have shown that they do not have an appreciable effect on thrust measurements. The thrust stand’s sensitivity can be adjusted by shifting the position of the coupling magnet inside the stand’s thrust support member, which allows flexibility for testing both higher and lower powered thrusters. The thrust stand has been modeled theoretically and the predicted results from the model are compared with experimentally measured data. The system was tested using a simple cold gas thruster and provided credible results that can be compared with other systems studied in the literature. Advantages include that the thrust stand is very cheap and easy to construct and further, the calibration process takes no longer than half an hour, facilitating rapid turnaround times while still retaining accuracy. Repeatability tests have shown that the balance gives consistent results.

  4. Plasma, magnetic, and electromagnetic measurements at nonmagnetic bodies

    Science.gov (United States)

    Russell, C. T.; Luhmann, J. G.

    The need to explore the magnetospheres of the Earth and the giant planets is widely recognized and is an integral part of our planetary exploration program. The equal need to explore the plasma, magnetic, and electromagnetic environments of the nonmagnetic bodies is not so widely appreciated. The previous, albeit incomplete, magnetic and electric field measurements at Venus, Mars, and comets have proven critical to our understanding of their atmospheres and ionospheres in areas ranging from planetary lightning to solar wind scavenging and accretion. In the cases of Venus and Mars, the ionospheres can provide communication paths over the horizon for low-altitude probes and landers, but we know little about their lower boundaries. The expected varying magnetic fields below these planetary ionospheres penetrates the planetary crusts and can be used to sound the electrical conductivity and the thermal profiles of the interiors. However, we have no knowledge of the levels of such fields, let alone their morphology. Finally, we note that the absence of an atmosphere and an ionosphere does not make an object any less interesting for the purposes of electromagnetic exploration. Even weak remanent magnetism such as that found on the Moon during the Apollo program provides insight into the present and past states of planetary interiors. We have very intriguing data from our space probes during times of both close and distant passages of asteroids that suggest they may have coherent magnetization. If true, this observation will put important constraints on how the asteroids formed and have evolved. Our planetary exploration program must exploit its full range of exploration tools if it is to characterize the bodies of the solar system thoroughly. We should especially take advantage of those techniques that are proven and require low mass, low power, and low telemetry rates to undertake.

  5. Sixth generation lithospheric magnetic field model, MF6, from CHAMP satellite magnetic measurements

    Science.gov (United States)

    Maus, S.; Fan, Y.; Manoj, C.; Rother, M.; Rauberg, J.; Stolle, C.; Luhr, H.

    2007-12-01

    The CHAMP satellite continues to provide highly accurate magnetic field measurements with decreasing orbital altitudes (<350km) at solar minimum conditions. A promising new CHAMP data product has become available, which provides the total field with one order of magnitude smaller noise amplitudes. The product is inferred from suitably merged Fluxgate and Overhauser magnetometer data. While the low-noise Fluxgate measurements are used in the short-period range (<900sec, or <6000km wavelength), we take advantage of the high stability provided by the Overhauser for the longer periods. The new data set is used for generating an improved lithospheric magnetic field model (MF6). Although MF6 is still in production at the time of writing this abstract, we anticipate significant benefits in terms of resolving small- scale low-amplitude crustal features from the new data. Further improvements include a new correction for steady ocean circulation and an expansion to higher spherical harmonic degrees of the model.

  6. Sensitivity analysis of magnetic field measurements for magnetic resonance electrical impedance tomography (MREIT)

    DEFF Research Database (Denmark)

    Göksu, Cihan; Scheffler, Klaus; Ehses, Philipp

    2017-01-01

    : The efficiency simulations and experimental results are in good agreement. When using optimal parameters, DBz,c can be reliably measured in the phantom even at injected current strengths of 1 mA or lower for both sequence types. The importance of using proper crusher gradient selection on the phase evolution...... in a MESE experiment is also demonstrated. Conclusion: The efficiencies observed with the optimized sequence parameters will likely render in-vivo human brain MREIT feasible.......Purpose: Clinical use of magnetic resonance electrical impedance tomography (MREIT) still requires significant sensitivity improvements. Here, the measurement of the current-induced magnetic field (DBz,c) is improved using systematic efficiency analyses and optimization of multi-echo spin echo...

  7. Measuring the Earth’s Magnetic Field from Space

    DEFF Research Database (Denmark)

    Olsen, Nils; Hulot, G.; Sabaka, T. J.

    2010-01-01

    Observations of the Earth’s magnetic field from low-Earth orbiting (LEO) satellites started very early on, more than 50 years ago. Continuous such observations, relying on more advanced technology and mission concepts, have however only been available since 1999. The unprecedented time......-space coverage of this recent data set opened revolutionary new possibilities for monitoring, understanding and exploring the Earth’s magnetic field. In the near future, the three-satellite Swarm constellation concept to be launched by ESA, will not only ensure continuity of such measurements, but also provide...... enhanced possibilities to improve on our ability to characterize and understand the many sources that produce this field. In the present paper we review and discuss the advantages and drawbacks of the various LEO space magnetometry concepts that have been used so far, and report on the motivations that led...

  8. Magnetic Resonance Image Segmentation and its Volumetric Measurement

    Directory of Open Access Journals (Sweden)

    Rahul R. Ambalkar

    2013-02-01

    Full Text Available Image processing techniques make it possible to extract meaningful information from medical images. Magnetic resonance (MR imaging has been widely applied in biological research and diagnostics because of its excellent soft tissue contrast, non-invasive character, high spatial resolution and easy slice selection at any orientation. The MRI-based brain volumetric is concerned with the analysis of volumes and shapes of the structural components of the human brain. It also provides a criterion, by which we recognize the presence of degenerative diseases and characterize their rates of progression to make the diagnosis and treatments as a easy task. In this paper we have proposed an automated method for volumetric measurement of Magnetic Resonance Imaging and used Self Organized Map (SOM clustering method for their segmentations. We have used the MRI data set of 61 slices of 256×256 pixels in DICOM standard format

  9. Local viscoelasticity of living cells measured by rotational magnetic spectroscopy.

    Science.gov (United States)

    Berret, J-F

    2016-01-05

    When submitted to a magnetic field, micron-size wires with superparamagnetic properties behave as embedded rheometers and represent interesting sensors for microrheology. Here we use rotational magnetic spectroscopy to measure the shear viscosity of the cytoplasm of living cells. We address the question of whether the cytoplasm is a viscoelastic liquid or an elastic gel. The main result of the study is the observation of a rotational instability between a synchronous and an asynchronous regime of rotation, found for murine fibroblasts and human cancer cells. For wires of susceptibility 3.6, the transition occurs in the range 0.01-1 rad s(-1). The determination of the shear viscosity (10-100 Pa s) and elastic modulus (5-20 Pa) confirms the viscoelastic character of the cytoplasm. In contrast to earlier studies, it is concluded that the interior of living cells can be described as a viscoelastic liquid, and not as an elastic gel.

  10. First measurements of cosmic muons with magnetic field in CMS

    Energy Technology Data Exchange (ETDEWEB)

    Biallass, P; Hebbeker, T; Hoepfner, K [Physics Institute IIIA, RWTH Aachen, Physikzentrum, 52056 Aachen (Germany)], E-mail: biallass@cern.ch

    2008-05-15

    The reconstruction of cosmic muons is important for testing and aligning the Compact Muon Solenoid experiment (CMS). In this context the Magnet Test and Cosmic Challenge (MTCC) with its comprehensive cosmic data taking periods including the presence of the 4 Tesla magnetic field has been like a dress rehearsal of detector hardware and software for the upcoming startup of the CMS detector. In addition to data taking also the comparison with simulated events is a crucial part of physics analyses. With respect to these tasks a dedicated cosmic muon generator, CMSCGEN, has been developed and compared with data from MTCC. As an example results from a reconstruction study using the barrel muon system are shown, comparing data and Monte Carlo prediction at the level of single chambers up to reconstructed tracks including momentum measurements.

  11. Quantum correlations of lights in macroscopic environments

    Science.gov (United States)

    Sua, Yong Meng

    This dissertation presents a detailed study in exploring quantum correlations of lights in macroscopic environments. We have explored quantum correlations of single photons, weak coherent states, and polarization-correlated/polarization-entangled photons in macroscopic environments. These included macroscopic mirrors, macroscopic photon number, spatially separated observers, noisy photons source and propagation medium with loss or disturbances. We proposed a measurement scheme for observing quantum correlations and entanglement in the spatial properties of two macroscopic mirrors using single photons spatial compass state. We explored the phase space distribution features of spatial compass states, such as chessboard pattern by using the Wigner function. The displacement and tilt correlations of the two mirrors were manifested through the propensities of the compass states. This technique can be used to extract Einstein-Podolsky-Rosen correlations (EPR) of the two mirrors. We then formulated the discrete-like property of the propensity P b(m,n), which can be used to explore environmental perturbed quantum jumps of the EPR correlations in phase space. With single photons spatial compass state, the variances in position and momentum are much smaller than standard quantum limit when using a Gaussian TEM 00 beam. We observed intrinsic quantum correlations of weak coherent states between two parties through balanced homodyne detection. Our scheme can be used as a supplement to decoy-state BB84 protocol and differential phase-shift QKD protocol. We prepared four types of bipartite correlations +/- cos2(theta1 +/- theta 2) that shared between two parties. We also demonstrated bits correlations between two parties separated by 10 km optical fiber. The bits information will be protected by the large quantum phase fluctuation of weak coherent states, adding another physical layer of security to these protocols for quantum key distribution. Using 10 m of highly nonlinear

  12. A METHODOLOGY TO INTEGRATE MAGNETIC RESONANCE AND ACOUSTIC MEASUREMENTS FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Jorge O. Parra; Chris L. Hackert; Lorna L. Wilson

    2002-09-20

    The work reported herein represents the third year of development efforts on a methodology to interpret magnetic resonance and acoustic measurements for reservoir characterization. In this last phase of the project we characterize a vuggy carbonate aquifer in the Hillsboro Basin, Palm Beach County, South Florida, using two data sets--the first generated by velocity tomography and the second generated by reflection tomography. First, we integrate optical macroscopic (OM), scanning electron microscope (SEM) and x-ray computed tomography (CT) images, as well as petrography, as a first step in characterizing the aquifer pore system. This pore scale integration provides information with which to evaluate nuclear magnetic resonance (NMR) well log signatures for NMR well log calibration, interpret ultrasonic data, and characterize flow units at the field scale between two wells in the aquifer. Saturated and desaturated NMR core measurements estimate the irreducible water in the rock and the variable T{sub 2} cut-offs for the NMR well log calibration. These measurements establish empirical equations to extract permeability from NMR well logs. Velocity and NMR-derived permeability and porosity relationships integrated with velocity tomography (based on crosswell seismic measurements recorded between two wells 100 m apart) capture two flow units that are supported with pore scale integration results. Next, we establish a more detailed picture of the complex aquifer pore structures and the critical role they play in water movement, which aids in our ability to characterize not only carbonate aquifers, but reservoirs in general. We analyze petrography and cores to reveal relationships between the rock physical properties that control the compressional and shear wave velocities of the formation. A digital thin section analysis provides the pore size distributions of the rock matrix, which allows us to relate pore structure to permeability and to characterize flow units at the

  13. Analysis and measurement of the 3D magnetic field in a rotating magnetic field driven FRC

    Science.gov (United States)

    Velas, K. M.; Milroy, R. D.

    2012-10-01

    A translatable three-axis probe was installed on TCSU shortly before its shutdown. The probe has 90 windings that simultaneously measure Br, Bθ, and Bz at 30 radial positions. Positioning the probe at multiple axial positions and taking multiple repeatable shots allows for a full r-z map of the magnetic field. Probe measurements are used to calculate the end-shorting torque and the rotating magnetic field (RMF) torque. The torque applied to the plasma is the RMF torque reduced by the shorting torque. An estimate of the plasma resistivity is made based on the steady state balance between the applied torque and the resistive torque. The steady state data from applying a 10 kHz low pass filter used in conjunction with data at the RMF frequency yields a map of the full 3D rotating field structure. Data from even- and odd-parity experiments will be presented. The NIMROD code has been adapted to simulate the TCSU experiment using boundary conditions adjusted to match both even- and odd-parity experimental conditions. A comparison of the n=0 components of the calculated fields to the 3-axis probe measurements shows agreement in the magnetic field structure of the FRC as well as in the jet region.

  14. An Air Bearing Rotating Coil Magnetic Measurement System

    CERN Document Server

    Gottschalk, Stephen C; Taylor, David J; Thayer, William

    2005-01-01

    This paper describes a rotating coil magnetic measurement system supported on air bearings. The design is optimized for measurements of 0.1micron magnetic centerline changes on long, small aperture quadrupoles. Graphite impregnated epoxy resin is used for the coil holder and coil winding forms. Coil holder diameter is 11 mm with a length between supports of 750mm. A pair of coils is used to permit quadrupole bucking during centerline measurements. Coil length is 616mm, inner radius 1.82mm, outer radius 4.74mm. The key features of the mechanical system are simplicity; air bearings for accurate, repeatable measurements without needing warm up time and a vibration isolated stand that uses a steel-topped Newport optical table with air suspension. Coil rotation is achieved by a low noise servo motor controlled by a standalone Ethernet servo board running custom servo software. Coil calibration procedures that correct wire placement errors, tests for mechanical resonances, and other system checks will also be discu...

  15. Lorentz force electrical impedance tomography using magnetic field measurements.

    Science.gov (United States)

    Zengin, Reyhan; Gençer, Nevzat Güneri

    2016-08-21

    In this study, magnetic field measurement technique is investigated to image the electrical conductivity properties of biological tissues using Lorentz forces. This technique is based on electrical current induction using ultrasound together with an applied static magnetic field. The magnetic field intensity generated due to induced currents is measured using two coil configurations, namely, a rectangular loop coil and a novel xy coil pair. A time-varying voltage is picked-up and recorded while the acoustic wave propagates along its path. The forward problem of this imaging modality is defined as calculation of the pick-up voltages due to a given acoustic excitation and known body properties. Firstly, the feasibility of the proposed technique is investigated analytically. The basic field equations governing the behaviour of time-varying electromagnetic fields are presented. Secondly, the general formulation of the partial differential equations for the scalar and magnetic vector potentials are derived. To investigate the feasibility of this technique, numerical studies are conducted using a finite element method based software. To sense the pick-up voltages a novel coil configuration (xy coil pairs) is proposed. Two-dimensional numerical geometry with a 16-element linear phased array (LPA) ultrasonic transducer (1 MHz) and a conductive body (breast fat) with five tumorous tissues is modeled. The static magnetic field is assumed to be 4 Tesla. To understand the performance of the imaging system, the sensitivity matrix is analyzed. The sensitivity matrix is obtained for two different locations of LPA transducer with eleven steering angles from [Formula: see text] to [Formula: see text] at intervals of [Formula: see text]. The characteristics of the imaging system are shown with the singular value decomposition (SVD) of the sensitivity matrix. The images are reconstructed with the truncated SVD algorithm. The signal-to-noise ratio in measurements is assumed 80 d

  16. Lorentz force electrical impedance tomography using magnetic field measurements

    Science.gov (United States)

    Zengin, Reyhan; Güneri Gençer, Nevzat

    2016-08-01

    In this study, magnetic field measurement technique is investigated to image the electrical conductivity properties of biological tissues using Lorentz forces. This technique is based on electrical current induction using ultrasound together with an applied static magnetic field. The magnetic field intensity generated due to induced currents is measured using two coil configurations, namely, a rectangular loop coil and a novel xy coil pair. A time-varying voltage is picked-up and recorded while the acoustic wave propagates along its path. The forward problem of this imaging modality is defined as calculation of the pick-up voltages due to a given acoustic excitation and known body properties. Firstly, the feasibility of the proposed technique is investigated analytically. The basic field equations governing the behaviour of time-varying electromagnetic fields are presented. Secondly, the general formulation of the partial differential equations for the scalar and magnetic vector potentials are derived. To investigate the feasibility of this technique, numerical studies are conducted using a finite element method based software. To sense the pick-up voltages a novel coil configuration (xy coil pairs) is proposed. Two-dimensional numerical geometry with a 16-element linear phased array (LPA) ultrasonic transducer (1 MHz) and a conductive body (breast fat) with five tumorous tissues is modeled. The static magnetic field is assumed to be 4 Tesla. To understand the performance of the imaging system, the sensitivity matrix is analyzed. The sensitivity matrix is obtained for two different locations of LPA transducer with eleven steering angles from -{{25}\\circ} to {{25}\\circ} at intervals of {{5}\\circ} . The characteristics of the imaging system are shown with the singular value decomposition (SVD) of the sensitivity matrix. The images are reconstructed with the truncated SVD algorithm. The signal-to-noise ratio in measurements is assumed 80 dB. Simulation studies

  17. Measurement of transverse Jc profiles of coated conductors using a magnetic knife of permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Haenisch, J [Los Alamos National Laboratory; Mueller, F M [Los Alamos National Laboratory; Ashworth, S P [Los Alamos National Laboratory; Coulter, J Y [Los Alamos National Laboratory; Matias, Vlad [Los Alamos National Laboratory

    2008-01-01

    The transverse J{sub c} distribution in YBCO coated conductors was measured non-destructively with high resolution using a 'magnetic knife' made of permanent magnets. The method utilizes the strong depression of J{sub c} in applied magnetic fields. A narrow region of low (including zero) magnetic field, in a surrounding higher field, is moved transversely across the sample in order to reveal the critical-current density distribution. The net resolution of this device is approximately 65 {micro}m, and the J{sub c} resolution is better than 0.5%. A Fourier series inversion process was used to determine the transverse J{sub c} distribution in the sample. The J{sub c} profile was correlated with other sample properties of coated conductors prepared by pulsed laser deposition. Because of its straight-forward and inexpensive design, this J{sub c} imaging technique can be a powerful tool for quality control in coated-conductor production.

  18. The magnetic flux leakage measurement by the hall sensor in the longitudinal magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Gwang Tae [Korea Industrial Testing Co., Ltd., Seoul (Korea, Republic of); Son, Dae Rok; Han, Jung Hee; Park, Jae Hyung [Dept. of Physics, Hannam University, Daejeon (Korea, Republic of)

    1998-05-15

    This paper is concerned with magnetic leakage flux measurement using by the hall sensor in the longitudinal magnetic field of the feromagnetic specimen. For detection sensitivity by the hall probe according to various depth of the subsurface defects, the specimen are prepared by six drilled holes of 0.5 mm φ from 1 mm depth to 4 mm depth in the carbon steel plate(10 x 35 x 265 mm). When the specimen applied by various frequency(2 - 9 Hz) of the AC through synthesizer and power amplifier in the yoke, the signals of the magnetic flux leakage using lack-in amplifier and synthesizer are decreased linearly with defect depth at 2 Hz, but these signals are decreased suddenly with defect depth from the surface and obscured with increasing frequency. And, when the specimen applied range of 1 Amp. to 5 Amp. by DC power supply in the yoke, the signals of the magnetic flux leakage through DVM decreased linearly with defect depth up to 2.5 mm depth and change slightly defect depth above 2.5 mm depth from the surface, but its signals appeared predominately.

  19. Measurement Of Transverse Jc Profiles Of Coated Conductors Using A Magnetic Knife Of Permanent Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Hanisch, J [Los Alamos National Laboratory; Mueller, F M [Los Alamos National Laboratory; Ashworth, S P [Los Alamos National Laboratory; Coulter, J Y [Los Alamos National Laboratory; Matias, Vlad [Los Alamos National Laboratory

    2008-01-01

    The transverse J{sub c} distribution in YBCO coated conductors was measured nondestructively with high resolution using a 'magnetic knife' made of permanent magnets. The method utilizes the strong depression of J{sub c} in applied magnetic fields. A narrow region of low (including zero) magnetic field, in a surrounding higher field, is moved transversely across the sample in order to reveal the critical-current density distribution. The net resolution of this device is approximately 65 {mu}m, and the J{sub c} resolution is better than 0.5%. A Fourier series inversion process was used to determine the transverse J{sub c} distribution in the sample. The J{sub c} profile was correlated with other sample properties of coated conductors prepared by pulsed laser deposition. Because of its straight-forward and inexpensive design, this J{sub c} imaging technique can be a powerful tool for quality control in coated-conductor production.

  20. Variability of macroscopic dimensions of Moso bamboo.

    Science.gov (United States)

    Cui, Le; Peng, Wanxi; Sun, Zhengjun; Sun, Zhengjun; Sun, Zhengjun; Lu, Huangfei; Chen, Guoning

    2015-03-01

    In order to the macroscopic geometry distributions of vascular bundles in Moso bamboo tubes. The circumference of bamboo tubes was measured, used a simple quadratic diameter formula to analyze the differences between the tubes in bamboo culm, and the arrangement of vascular bundles was investigated by cross sectional images of bamboo tubes. The results shown that the vascular bundles were differently distributed in a bamboo tube. In the outer layer, the vascular bundles had a variety of shapes, and were aligned parallel to each other. In the inner layers, the vascular bundles weren't aligned but uniform in shape. It was concluded that the vascular bundle sections arranged in parallel should be separated from the non-parallel sections for the maximum bamboo utilization.

  1. On the notion of a macroscopic quantum system

    CERN Document Server

    Khrenikov, A Yu

    2004-01-01

    We analyse the notion of macroscopic quantum system from the point of view of the statistical structure of quantum theory. We come to conclusion that the presence of interference of probabilities should be used the main characteristic of quantumness (in the opposition to N. Bohr who permanently emphasized the crucial role of quantum action). In the light of recent experiments with statistical ensembles of people who produced interference of probabilities for special pairs of questions (which can be considered as measurements on people) human being should be considered as a macroscopic quantum system. There is also discussed relation with experiments of A. Zeilinger on interference of probabilities for macromoleculas.

  2. Measuring interstellar magnetic fields by radio synchrotron emission

    CERN Document Server

    Beck, Rainer

    2009-01-01

    Radio synchrotron emission, its polarization and its Faraday rotation are powerful tools to study the strength and structure of interstellar magnetic fields. The total intensity traces the strength and distribution of total magnetic fields. Total fields in gas-rich spiral arms and bars of nearby galaxies have strengths of 20-30 $\\mu$Gauss, due to the amplification of turbulent fields, and are dynamically important. In the Milky Way, the total field strength is about 6 $\\mu$G near the Sun and several 100 $\\mu$G in filaments near the Galactic Center. -- The polarized intensity measures ordered fields with a preferred orientation, which can be regular or anisotropic fields. Ordered fields with spiral structure exist in grand-design, barred, flocculent and even in irregular galaxies. The strongest ordered fields are found in interarm regions, sometimes forming "magnetic spiral arms" between the optical arms. Halo fields are X-shaped, probably due to outflows. -- The Faraday rotation of the polarization vectors tr...

  3. Highly Accurate Measurement of the Electron Orbital Magnetic Moment

    CERN Document Server

    Awobode, A M

    2015-01-01

    We propose to accurately determine the orbital magnetic moment of the electron by measuring, in a Magneto-Optical or Ion trap, the ratio of the Lande g-factors in two atomic states. From the measurement of (gJ1/gJ2), the quantity A, which depends on the corrections to the electron g-factors can be extracted, if the states are LS coupled. Given that highly accurate values of the correction to the spin g-factor are currently available, accurate values of the correction to the orbital g-factor may also be determined. At present, (-1.8 +/- 0.4) x 10-4 has been determined as a correction to the electron orbital g-factor, by using earlier measurements of the ratio gJ1/gJ2, made on the Indium 2P1/2 and 2P3/2 states.

  4. A measurement system of magnetism parameters for motion control

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-ming; HUANG Xu-yan; LEI Tao

    2007-01-01

    Magnetism parameters vary with the position and the speed of electromagnetic actuator's motion parts. The measurement unit presented in the paper can be applied to get the position and the speed feedback information from the measurement of electromagnetism parameters, and can constitute the untouched feedback sensing unit in the closed-loop motion control, and it adapts to the diversified feedback control of electromagnetic actuator. The digital miniaturization meter, based on MSP430 single chip processor, which can do the multiformance evaluation and improvement, and also the online quality control in production process. Both real-time data graph and data table can be displayed in the meter. The paper presents the system's structure, describes the principle, discusses the working modes, and shows the software flowchart and the measuring results.

  5. Improved Measurement of the Positive Muon Anomalous Magnetic Moment

    CERN Document Server

    Brown, H N; Carey, R M; Cushman, P B; Danby, G T; Debevec, P T; Deng, H; Deninger, W J; Dhawan, S K; Druzhinin, V P; Duong, L; Earle, W; Efstathiadis, E F; Fedotovich, G V; Farley, Francis J M; Giron, S; Gray, F; Grosse-Perdekamp, M; Grossmann, A; Haeberlen, U; Hare, M; Hazen, E S; Hertzog, D W; Hughes, V W; Iwasaki, M; Jungmann, Klaus; Kawall, D; Kawamura, M; Khazin, B I; Kindem, J; Krienen, F; Kronkvist, I J; Larsen, R; Lee, Y Y; Logashenko, I B; McNabb, R; Meng, W; Mi, J; Miller, J P; Morse, W M; Onderwater, Gerco; Orlov, Yu F; Ozben, C; Polly, C; Pai, C; Paley, J M; Pretz, J; Prigl, R; zu Putlitz, Gisbert; Redin, S I; Rind, O; Roberts, B L; Ryskulov, N M; Sedykh, S N; Semertzidis, Y K; Shatunov, Yu M; Solodov, E P; Sossong, M; Steinmetz, A; Sulak, Lawrence R; Timmermans, C; Trofimov, A V; Urner, D; Von Walter, P; Warburton, D; Winn, D; Yamamoto, A; Zimmerman, D

    2000-01-01

    A new measurement of the positive muon's anomalous magnetic moment has been made at the Brookhaven Alternating Gradient Synchrotron using the direct injection of polarized muons into the superferric storage ring. The angular frequency difference omega_{a} between the angular spin precession frequency omega_{s} and the angular orbital frequency omega_{c} is measured as well as the free proton NMR frequency omega_{p}. These determine R = omega_{a} / omega_{p} = 3.707~201(19) times 10^{-3}. With mu_{mu} / mu_{p} = 3.183~345~39(10) this gives a_{mu^+} = 11~659~191(59) times 10^{-10} (pm 5 ppm), in good agreement with the previous CERN and BNL measurements for mu^+ and mu^-, and with the standard model prediction.

  6. Neutron Lifetime Measurement Using Magnetically Trapped Ultracold Neutrons

    Science.gov (United States)

    Huffer, Craig; Huffman, P. R.; Schelhammer, K. W.; Dewey, M. S.; Huber, M. G.; Hughes, P. P.; Mumm, H. P.; Thompson, A. K.; Coakley, K.; Yue, A. T.; O'Shaughnessy, C. M.

    2017-01-01

    The neutron beta-decay lifetime is important in both nuclear astrophysics and in understanding weak interactions in the framework of the Standard Model. An experiment based at the NIST Center for Neutron Research was designed to address statistical and systematic limitations of former measurements. In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. Some of the neutrons are subsequently downscattered by single phonons in the helium to low energies (decays the energetic electron produces a scintillation signal in the helium that is detected in real time using photomultiplier tubes. The current measurement is limited by larger than expected systematic corrections. We will discuss the result of the latest dataset and comment on the potential of future measurements.

  7. New limits on extragalactic magnetic fields from rotation measures

    CERN Document Server

    Pshirkov, Maxim S; Urban, Federico R

    2015-01-01

    We take advantage of the wealth of rotation measures data contained in the NVSS catalogue to derive new, statistically robust, upper limits on the strength of extragalactic magnetic fields. We simulate the extragalactic contribution to the rotation measures for a given field strength and correlation length, by assuming that the electron density follows the distribution of Lyman-$\\alpha$ clouds. Based on the observation that rotation measures from low-luminosity distant radio sources do not exhibit any trend with redshift, while the extragalactic contribution instead grows with distance, we constrain fields with Mpc coherence length to be below 1.2 nG at the $2\\sigma$ level, and fields coherent across the entire observable Universe below 0.5 nG. These limits do not depend on the particular origin of these cosmological fields.

  8. Magnetic tunnel junctions with integrated thermometers for magnetothermopower measurements

    Science.gov (United States)

    Böhnert, T.; Serrano-Guisan, S.; Paz, E.; Lacoste, B.; Ferreira, R.; Freitas, P. P.

    2017-05-01

    Magnetic tunnel junction (MTJ) micropillars were fabricated with integrated thermometers and a heater line (HL) for thermovoltage measurements. This novel thermometer configuration enabled a direct measurement of ΔT across the MTJ micropillar. The MTJ devices were patterned from a CoFeB/MgO/CoFeB stack, with a 1.2 nm to 1.6 nm MgO wedge across the wafer, resulting in resistance area products in the range of 0.7 kΩ · µm2  MTJ structure and the thermopower were estimated with a noticeable improvement of the measurement accuracy. The studied MTJ structures showed tunneling magnetoresistance (TMR) ratios up to 125%, and tunneling magnetothermopower (TMTP) up to 35%.

  9. Magnetic field measurements near stand-alone transformer stations.

    Science.gov (United States)

    Kandel, Shaiela; Hareuveny, Ronen; Yitzhak, Nir-Mordechay; Ruppin, Raphael

    2013-12-01

    Extremely low-frequency (ELF) magnetic field (MF) measurements around and above three stand-alone 22/0.4-kV transformer stations have been performed. The low-voltage (LV) cables between the transformer and the LV switchgear were found to be the major source of strong ELF MFs of limited spatial extent. The strong fields measured above the transformer stations support the assessment method, to be used in future epidemiological studies, of classifying apartments located right above the transformer stations as highly exposed to MFs. The results of the MF measurements above the ground around the transformer stations provide a basis for the assessment of the option of implementing precautionary procedures.

  10. Magnetic noise measurements using cross-correlated Hall sensor arrays

    Science.gov (United States)

    Jung, G.; Ocio, M.; Paltiel, Y.; Shtrikman, H.; Zeldov, E.

    2001-01-01

    An experimental technique for measuring magnetic fluctuations by means of a double-layer Hall sensor array is described. The technique relies on cross-correlating Hall signals from two independent sensors positioned one above the other in two separate two-dimensional-electron-gas layers of a GaAs/AlGaAs heterostructure. The effectiveness of the technique is demonstrated by a reduction of the magnitude of the background noise floor of the correlated sensors with respect to the noise level of the best single sensor.

  11. Automated cyclotron magnetic field measurement at the University of Manitoba

    Science.gov (United States)

    Derenchuk, V.; Bruckshaw, J.; Gusdal, I.; Lancaster, J.; McIlwain, A.; Oh, S.; Pogson, R.; McKee, J. S. C.

    The magnetic field of the University of Manitoba compact cyclotron has been measured in high vacuum by polar scanning with 52 flip coils. This was a unique invacuo operation was required because the Curie effect on invar material is used to trim the field. The data acquisition controller was a Digital Equipment Corporation LSI-11 with CAMAC and IEEE-488 interfaces. Filtering, display and conventional equilibrium orbit analysis were performed off-line by means of a VAX-11/750 computer. A description of the apparatus and software is given.

  12. Low magnetic Johnson noise electric field plates for precision measurement

    CERN Document Server

    Rabey, I M; Hinds, E A; Sauer, B E

    2016-01-01

    We describe a parallel pair of high voltage electric field plates designed and constructed to minimise magnetic Johnson noise. They are formed by laminating glass substrates with commercially available polyimide (Kapton) tape, covered with a thin gold film. Tested in vacuum, the outgassing rate is less than $5\\times10^{-5}$ mbar.l/s. The plates have been operated at electric fields up to 8.3 kV/cm, when the leakage current is at most a few hundred pA. The design is discussed in the context of a molecular spin precession experiment to measure the permanent electric dipole moment of the electron.

  13. Measurement of the zero-field magnetic dipole moment of magnetizable colloidal silica spheres

    Energy Technology Data Exchange (ETDEWEB)

    Claesson, E M; Erne, B H; Bakelaar, I A; Kuipers, B W M; Philipse, A P [Van' t Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands)

    2007-01-24

    The magnetic properties of dispersions of magnetic silica microspheres have been investigated by measuring the magnetization curves and the complex magnetic susceptibility as a function of frequency and field amplitude. The silica spheres appear to have a net permanent magnetic dipole moment, even in zero field, which is increased significantly after a temporary exposure of the silica colloids to a saturating magnetic field. The magnetic properties of the microparticles in zero field are discussed in terms of the number and the orientations of the embedded nanoparticle dipoles along an easy axis of magnetization in the absence of an external field.

  14. Study on the magnetic measurement results of the injection system for CSNS/RCS

    CERN Document Server

    Huang, Ming-Yang; Huang, Nan; Huo, Li-Hua; Ji, Hong-Fei; Kang, Wen; Liu, Yi-Qin; Peng, Jun; Qiu, Jing; Shen, Li; Wang, Sheng; Wu, Xi; Xu, Shou-Yan; Zhang, Jing; Zhou, Guo-Zhong

    2016-01-01

    A combination of the H- stripping and phase space painting method is used to accumulate a high intensity beam in the Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS). The injection system for CSNS/RCS consists of three kinds of magnets: four direct current magnets (BC1-BC4), eight alternating current magnets (BH1-BH4 and BV1-BV4), two septum magnets (ISEP1 and ISEP2). In this paper, the magnetic measurements of the injection system were introduced and the data analysis was processed. The field uniformity and magnetizing curves of these magnets were given, and then the magnetizing fitting equations were obtained.

  15. Photoinduced macroscopic chiral structures in a series of azobenzene copolyesters

    DEFF Research Database (Denmark)

    Nedelchev, L.; Nikolova, L.; Matharu, A.

    2002-01-01

    A study of the propagation of elliptically polarized light and the resulting formation of macroscopic chiral structures in a series of azobenzene side-chain copolyesters, in which the morphology is varied from liquid crystalline to amorphous, is reported. Real-time measurements are presented...

  16. Trapped magnetic field measurements on HTS bulk by peak controlled pulsed field magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Ida, Tetsuya; Watasaki, Masahiro [Department of Electronic Control Engineering, Hiroshima National College of Maritime Technology, 4272-1, Higashino, Ohsakikamijima-cho, Toyota-gun, Hiroshima 725-0231 (Japan); Kimura, Yosuke [Kawasaki Heavy Industries, Ltd. Technical Institute System Technology Development Centre 1-1, Kawasaki-cho, Akashi-shi, Hyogo 673-8666 (Japan); Miki, Motohiro; Izumi, Mitsuru, E-mail: ida@hiroshima-cmt.ac.j [Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan)

    2010-06-01

    For the past several years, we have studied the high-temperature superconducting (HTS) synchronous motor assembled with melt-textured Gd-Ba-Cu-O bulk magnets. If the single pulse field magnetizes a bulk effectively, size of electrical motor will become small for the strong magnetic field of the HTS magnets without reducing output power of motor. In the previous study, we showed that the HTS bulk was magnetized to excellent cone-shape magnetic field distribution by using the waveform control pulse magnetization (WCPM) method. The WCPM technique made possible the active control of the waveform on which magnetic flux motion depended. We generated the pulse waveform with controlled risetime for HTS bulk magnetization to suppress the magnetic flux motion which decreases magnetization efficiency. The pulsed maximum magnetic flux density with slow risetime is not beyond the maximum magnetic flux density which is trapped by the static field magnetization. But, as for applying the pulse which has fast risetime, the magnetic flux which exceed greatly the threshold penetrates the bulk and causes the disorder of the trapped magnetic distribution. This fact suggests the possibility that the threshold at pulsed magnetization influences the dynamic magnetic flux motion. In this study, Gd-Ba-Cu-O bulk is magnetized by the controlled arbitrary trapezoidal shape pulse, of which the maximum magnetic flux density is controlled not to exceed the threshold. We will present the trapped magnetic characteristics and the technique to generate the controlled pulsed field.

  17. Macroscopic theory of dark sector

    CERN Document Server

    Meierovich, Boris E

    2013-01-01

    A simple Lagrangian with squared covariant divergence of a vector field as a kinetic term turned out an adequate tool for macroscopic description of the dark sector. The zero-mass field acts as the dark energy. Its energy-momentum tensor is a simple additive to the cosmological constant. Massive fields {\\phi}_{I} with {\\phi}^{K}{\\phi}_{K}0 describe two different forms of dark matter. The space-like ({\\phi}^{K}{\\phi}_{K}0) massive field displays repulsive elasticity. In balance with dark energy and ordinary matter it provides a four parametric diversity of regular solutions of the Einstein equations describing different possible cosmological and oscillating non-singular scenarios of evolution of the universe. In particular, the singular big bang turns into a regular inflation-like transition from contraction to expansion with the accelerate expansion at late times. The fine-tuned Friedman-Robertson-Walker singular solution is a particular limiting case at the boundary of existence of regular oscillating soluti...

  18. Magnetic-field sensing coil embedded in ceramic for measuring ambient magnetic field

    Science.gov (United States)

    Takahashi, Hironori

    2004-02-10

    A magnetic pick-up coil for measuring magnetic field with high specific sensitivity, optionally with an electrostatic shield (24), having coupling elements (22) with high winding packing ratio, oriented in multiple directions, and embedded in ceramic material for structural support and electrical insulation. Elements of the coil are constructed from green ceramic sheets (200) and metallic ink deposited on surfaces and in via holes of the ceramic sheets. The ceramic sheets and the metallic ink are co-fired to create a monolithic hard ceramic body (20) with metallized traces embedded in, and placed on exterior surfaces of, the hard ceramic body. The compact and rugged coil can be used in a variety of environments, including hostile conditions involving ultra-high vacuum, high temperatures, nuclear and optical radiation, chemical reactions, and physically demanding surroundings, occurring either individually or in combinations.

  19. Low-noise pulsed current source for magnetic-field measurements of magnets for accelerators

    Science.gov (United States)

    Omelyanenko, M. M.; Borisov, V. V.; Donyagin, A. M.; Khodzhibagiyan, H. G.; Kostromin, S. A.; Makarov, A. A.; Shemchuk, A. V.

    2017-01-01

    The schematic diagram, design, and technical characteristics of the pulsed current source developed and produced for the magnetic-field measurement system of superconducting magnets for accelerators are described. The current source is based on the current regulator with pass transistor bank in the linear mode. Output current pulses (0-100 A) are produced by utilizing the energy of the preliminarily charged capacitor bank (5-40 V), which is additionally charged between pulses. The output current does not have the mains frequency and harmonics ripple. The relative noise level is less than-100 dB (or 10-5) of RMS value (it is defined as the ratio of output RMS noise current to a maximal output current of 100 A within the operating bandwidth, expressed in dB). The work was performed at the Veksler and Baldin Laboratory of High Energy Physics, Joint Institute for Nuclear Research (JINR).

  20. MACROSCOPIC DIVERSITY FOR CDMA MOBILE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Pei Xiaoyan; Hu Jiandong

    2002-01-01

    A novel system of macroscopic diversity with voting rule in CDMA cellular system is suggested in order to raise the coverage and quality of service of CDMA mobile communication system. The estimation of the impact of macroscopic diversity on performance of CDMA cellular system is analyzed and investigated.

  1. MACROSCOPIC DIVERSITY FOR CDMA MOBILE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    PeiXiaoyan; HuJiandong

    2002-01-01

    A novel system of macroscopic diversity with voting rule in CDMA cellular system is suggested in order to raise the coverage and quality of service of CDMA mobile communication system.The estimation of the impact of macroscopic diversity on performance of CDMA cellular system is analyzed and investigated.

  2. Magnetic Susceptibility Measurements as a Proxy for Hydrocarbon Biodegradation

    Science.gov (United States)

    Mewafy, F.; Atekwana, E. A.; Slater, L. D.; Werkema, D.; Revil, A.; Ntarlagiannis, D.; Skold, M.

    2011-12-01

    Magnetic susceptibility (MS) measurements have been commonly used in paleoclimate studies, as a proxy for environmental pollution such as heavy metal contamination, and for delineating zones of oil seeps related to hydrocarbon exploration. Few studies have assessed the use of MS measurements for mapping zones of oil pollution. In this study, we investigated the variation in magnetic susceptibility across a hydrocarbon contaminated site undergoing biodegradation. Our objective was to investigate if MS measurements could be used as a proxy indicator of intrinsic bioremediation linked to the activity of iron reducing bacteria. An improved understanding of the mechanisms generating geophysical signatures associated with microbial enzymatic activity could permit the development of geophysical imaging technologies for long-term, minimally invasive and sustainable monitoring of natural biodegradation at oil spill sites. We used a Bartington MS probe to measure MS data along fifteen boreholes within contaminated (both free phase and dissolved phase hydrocarbon plumes) and clean areas. Our results show the following: (1) an enhanced zone of MS straddling the water table at the contaminated locations, not observed at the clean locations; (2) MS values within the free product plume are higher compared to values within the dissolved product plume; (3) the MS values within the vadoze zone above the free product plume are higher compared to values within the dissolved product plume; 4) the zone of high MS is thicker within the free product plume compared to the dissolved product plume. We suggest that the zone of enhanced MS results from the precipitation of magnetite related to the oxidation of the hydrocarbons coupled to iron reduction. Our data documents a strong correlation between MS and hydrocarbon concentration. We conclude that recognition of these zones of enhanced magnetite formation allows for the application of MS measurements as a: (1) low cost, rapid monitoring

  3. Magnetic Field Measurements in Wire-Array Z-Pinches

    Science.gov (United States)

    Syed, Wasif; Hammer, David; Lipson, Michal

    2006-10-01

    Understanding the evolution of the magnetic field topology and magnitude in the high energy density plasmas produced by wire-array Z-pinches is of critical importance for their ultimate application to stockpile stewardship and inertial confinement fusion^1. A method to determine the magnetic field profile in megampere level wire-array Z-pinches with high spatial and temporal resolution is under development. An ideal method would be passive and non-perturbing, such as Faraday rotation of laser light. We are developing a method involving temporally-resolved Faraday rotation through a sensing waveguide placed in the vicinity of, and eventually in, a wire-array Z-pinch^2. We present measurements of the magnetic field outside of a wire-array, and progress on measurements within the array. Our ideal device is a ``thin film waveguide'' coupled to an optical fiber system. While these sensing devices may not survive for long in a dense Z-pinch, they may provide useful information for a significant fraction of the current pulse. We present preliminary theoretical and experimental results. 1. M. Keith Matzen, M. A. Sweeney, R. G. Adams et al., Phys. Plasmas 12, 055503 (2005). 2. W. Syed, D. A. Hammer, M. Lipson, R. B. van Dover, AIP Proceedings of the 6th International Conference on Dense Z-Pinches, University of Oxford, UK, July 25-28, 2005. *This research was sponsored by the National Nuclear Security Administration under the Stockpile Stewardship Academic Alliances program through DOE Cooperative Agreement DE-F03-02NA00057.

  4. Accuracy of MRI-based Magnetic Susceptibility Measurements

    Science.gov (United States)

    Russek, Stephen; Erdevig, Hannah; Keenan, Kathryn; Stupic, Karl

    Magnetic Resonance Imaging (MRI) is increasingly used to map tissue susceptibility to identify microbleeds associated with brain injury and pathologic iron deposits associated with neurologic diseases such as Parkinson's and Alzheimer's disease. Field distortions with a resolution of a few parts per billion can be measured using MRI phase maps. The field distortion map can be inverted to obtain a quantitative susceptibility map. To determine the accuracy of MRI-based susceptibility measurements, a set of phantoms with paramagnetic salts and nano-iron gels were fabricated. The shapes and orientations of features were varied. Measured susceptibility of 1.0 mM GdCl3 solution in water as a function of temperature agreed well with the theoretical predictions, assuming Gd+3 is spin 7/2. The MRI susceptibility measurements were compared with SQUID magnetometry. The paramagnetic susceptibility sits on top of the much larger diamagnetic susceptibility of water (-9.04 x 10-6), which leads to errors in the SQUID measurements. To extract out the paramagnetic contribution using standard magnetometry, measurements must be made down to low temperature (2K). MRI-based susceptometry is shown to be as or more accurate than standard magnetometry and susceptometry techniques.

  5. Measuring the Magnetic Flux Density in the CMS Steel Yoke

    CERN Document Server

    Klyukhin, V I; Ball, A; Curé, B; Gaddi, A; Gerwig, H; Hervé, A; Mulders, M; Loveless, R

    2012-01-01

    The Compact Muon Solenoid (CMS) is a general purpose detector, designed to run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its distinctive features include a 4 T superconducting solenoid with 6-m-diameter by 12.5-m-length free bore, enclosed inside a 10000-ton return yoke made of construction steel. The return yoke consists of five dodecagonal three-layered barrel wheels and four end-cap disks at each end comprised of steel blocks up to 620 mm thick, which serve as the absorber plates of the muon detection system. Accurate characterization of the magnetic field everywhere in the CMS detector is required. To measure the field in and around the steel, a system of 22 flux-loops and 82 3-D Hall sensors is installed on the return yoke blocks. Fast discharges of the solenoid (190 s time-constant) made during the CMS magnet surface commissioning test at the solenoid central fields of 2.64, 3.16, 3.68 and 4.01 T were used to induce voltages in the flux-loops. The voltages are measured on-line a...

  6. Direct Measurement of Effective Magnetic Diffusivity in Turbulent Flow of Liquid Sodium

    CERN Document Server

    Frick, Peter; Denisov, Sergey; Stepanov, Rodion

    2010-01-01

    The first direct measurements of effective magnetic diffusivity in turbulent flow of electro-conductive fluids (the so-called beta-effect) under magnetic Reynolds number Rm >> 1 are reported. The measurements are performed in a nonstationary turbulent flow of liquid sodium, generated in a closed toroidal channel. The peak level of the Reynolds number reached Re \\approx 3 10^6, which corresponds to the magnetic Reynolds number Rm \\approx 30. The magnetic diffusivity of the liquid metal was determined by measuring the phase shift between the induced and the applied magnetic fields. The maximal deviation of magnetic diffusivity from its basic (laminar) value reaches about 50% .

  7. Direct measurement of effective magnetic diffusivity in turbulent flow of liquid sodium.

    Science.gov (United States)

    Frick, Peter; Noskov, Vitaliy; Denisov, Sergey; Stepanov, Rodion

    2010-10-29

    The first direct measurements of effective magnetic diffusivity in turbulent flow of electroconductive fluids (the so-called β effect) under the magnetic Reynolds number Rm≫1 are reported. The measurements are performed in a nonstationary turbulent flow of liquid sodium, generated in a closed toroidal channel. The peak level of the Reynolds number reached Re≈3×10(6), which corresponds to the magnetic Reynolds number Rm≈30. The magnetic diffusivity of the liquid metal was determined by measuring the phase shift between the induced and the applied magnetic fields. The maximal deviation of magnetic diffusivity from its laminar value reaches about 50%.

  8. Precision Measurement of the Anomalous Magnetic Moment of the Muon

    CERN Document Server

    Ozben, C S

    2002-01-01

    The muon g-2 experiment at Brookhaven National Laboratory measures the anomalous magnetic moment of the muon, $a_\\mu$, very precisely. This measurement tests the Standard Model theory. The analysis for the data collected in 2000 (a $\\mu^+$ run) is completed and the accuracy on $a_\\mu$ is improved to 0.7 ppm, including statistical and systematic errors. The data analysis was performed blindly between the precession frequency and the field analysis groups in order to prevent a possible bias in the $a_\\mu$ result. The observed difference between the theory and our most recent experimental result is quite important for further studies of the Standard Model theory. In 2001, we ran for the first time with $\\mu^-$ and the analysis of this data will provide $a_\\mu$ with similar statistical power.

  9. ANALYSIS OF THE MAGNETIC FIELD MEASURED BY A ROTATING HALL PROBE IN A SOLENOID TO LOCATE ITS MAGNETIC AXIS.

    Energy Technology Data Exchange (ETDEWEB)

    KPONOU,A.; PIKIN,A.; BEEBE,E.; ALESSI,J.

    2000-11-06

    We have analyzed the motion of a Hall probe, which is rotated about an axis that is arbitrarily displaced and oriented with respect to the magnetic axis of a solenoid. We outline how the magnetic field measured by the rotating Hall probe can be calculated. We show how to compare theoretical results with actual measurements, to determine the displacement and orientation of the axis of rotation of the probe from the magnetic axis. If the center of rotation of the probe is known by surveying, the corresponding point on the magnetic axis of the solenoid can be located. This is applied to a solenoid that was built for BNL by Oxford Instruments.

  10. Vanishing magnetic interactions in ferromagnetic thin films.

    Science.gov (United States)

    Dunn, J Hunter; Karis, O; Andersson, C; Arvanitis, D; Carr, R; Abrikosov, I A; Sanyal, B; Bergqvist, L; Eriksson, O

    2005-06-03

    We have used element-specific hysteresis measurements, based on the x-ray magnetic circular dichroism technique, to investigate magnetic trilayer structures composed of Fe and Ni layers. Within a critical regime we have discovered a class of structures in which the exchange interaction, the mechanism responsible for the macroscopic magnetism, can become vanishingly small. The experimental observations are supported by first principles theory and are explained as arising from a cancellation of several competing magnetic interactions. Hence, we have discovered a system with a novel exchange interaction between magnetic layers in direct contact that replaces the conventional exchange interaction in ferromagnets.

  11. Validation of conducting wall models using magnetic measurements

    Science.gov (United States)

    Hanson, J. M.; Bialek, J.; Turco, F.; King, J.; Navratil, G. A.; Strait, E. J.; Turnbull, A.

    2016-10-01

    The impact of conducting wall eddy currents on perturbed magnetic field measurements is a key issue for understanding the measurement and control of long-wavelength MHD stability in tokamak devices. As plasma response models have growth in sophistication, the need to understand and resolve small changes in these measurements has become more important, motivating increased fidelity in simulations of externally applied fields and the wall eddy current response. In this manuscript, we describe thorough validation studies of the wall models in the mars-f and valen stability codes, using coil-sensor vacuum coupling measurements from the DIII-D tokamak (Luxon et al 2005 Fusion Sci. Technol. 48 807). The valen formulation treats conducting structures with arbitrary three-dimensional geometries, while mars-f uses an axisymmetric wall model and a spectral decomposition of the problem geometry with a fixed toroidal harmonic n. The vacuum coupling measurements have a strong sensitivity to wall eddy currents induced by time-changing coil currents, owing to the close proximities of both the sensors and coils to the wall. Measurements from individual coil and sensor channels are directly compared with valen predictions. It is found that straightforward improvements to the valen model, such as refining the wall mesh and simulating the vertical extent of the DIII-D poloidal field sensors, lead to good agreement with the experimental measurements. In addition, couplings to multi-coil, n  =  1 toroidal mode perturbations are calculated from the measurements and compared with predictions from both codes. The toroidal mode comparisons favor the fully three-dimensional simulation approach, likely because this approach naturally treats n  >  1 sidebands generated by the coils and wall eddy currents, as well as the n  =  1 fundamental.

  12. Measuring the interaction force between a high temperature superconductor and a permanent magnet

    OpenAIRE

    Valenzuela, S. O.; Jorge, G. A.; Rodriguez, E.

    1999-01-01

    Repulsive and attractive forces are both possible between a superconducting sample and a permanent magnet, and they can give place to magnetic levitation or free-suspension phenomena, respectively. We show experiments to quantify this magnetic interaction which represents a promising field regarding to short-term technological applications of high temperature superconductors. The measuring technique employs an electronic balance and a rare-earth magnet that induces a magnetic moment in a melt...

  13. Rank distributions: A panoramic macroscopic outlook

    Science.gov (United States)

    Eliazar, Iddo I.; Cohen, Morrel H.

    2014-01-01

    This paper presents a panoramic macroscopic outlook of rank distributions. We establish a general framework for the analysis of rank distributions, which classifies them into five macroscopic "socioeconomic" states: monarchy, oligarchy-feudalism, criticality, socialism-capitalism, and communism. Oligarchy-feudalism is shown to be characterized by discrete macroscopic rank distributions, and socialism-capitalism is shown to be characterized by continuous macroscopic size distributions. Criticality is a transition state between oligarchy-feudalism and socialism-capitalism, which can manifest allometric scaling with multifractal spectra. Monarchy and communism are extreme forms of oligarchy-feudalism and socialism-capitalism, respectively, in which the intrinsic randomness vanishes. The general framework is applied to three different models of rank distributions—top-down, bottom-up, and global—and unveils each model's macroscopic universality and versatility. The global model yields a macroscopic classification of the generalized Zipf law, an omnipresent form of rank distributions observed across the sciences. An amalgamation of the three models establishes a universal rank-distribution explanation for the macroscopic emergence of a prevalent class of continuous size distributions, ones governed by unimodal densities with both Pareto and inverse-Pareto power-law tails.

  14. Preliminary Results of Performance Measurements on a Cylindrical Hall-Effect Thruster with Magnetic Field Generated by Permanent Magnets

    Science.gov (United States)

    Polzin, K. A.; Raitses, Y.; Merino, E.; Fisch, N. J.

    2008-01-01

    The performance of a low-power cylindrical Hall thruster, which more readily lends itself to miniaturization and low-power operation than a conventional (annular) Hall thruster, was measured using a planar plasma probe and a thrust stand. The field in the cylindrical thruster was produced using permanent magnets, promising a power reduction over previous cylindrical thruster iterations that employed electromagnets to generate the required magnetic field topology. Two sets of ring-shaped permanent magnets are used, and two different field configurations can be produced by reorienting the poles of one magnet relative to the other. A plasma probe measuring ion flux in the plume is used to estimate the current utilization for the two magnetic configurations. The measurements indicate that electron transport is impeded much more effectively in one configuration, implying a higher thrust efficiency. Preliminary thruster performance measurements on this configuration were obtained over a power range of 100-250 W. The thrust levels over this power range were 3.5-6.5 mN, with anode efficiencies and specific impulses spanning 14-19% and 875- 1425 s, respectively. The magnetic field in the thruster was lower for the thrust measurements than the plasma probe measurements due to heating and weakening of the permanent magnets, reducing the maximum field strength from 2 kG to roughly 750-800 G. The discharge current levels observed during thrust stand testing were anomalously high compared to those levels measured in previous experiments with this thruster.

  15. Chemical telemetry of OH observed to measure interstellar magnetic fields

    CERN Document Server

    Viti, S; Myers, P C

    2005-01-01

    We present models for the chemistry in gas moving towards the ionization front of an HII region. When it is far from the ionization front, the gas is highly depleted of elements more massive than helium. However, as it approaches the ionization front, ices are destroyed and species formed on the grain surfaces are injected into the gas phase. Photodissociation removes gas phase molecular species as the gas flows towards the ionization front. We identify models for which the OH column densities are comparable to those measured in observations undertaken to study the magnetic fields in star forming regions and give results for the column densities of other species that should be abundant if the observed OH arises through a combination of the liberation of H2O from surfaces and photodissociation. They include CH3OH, H2CO, and H2S. Observations of these other species may help establish the nature of the OH spatial distribution in the clouds, which is important for the interpretation of the magnetic field results.

  16. GHz measurements of correlated electron systems in high magnetic fields

    CERN Document Server

    Edwards, R S

    2002-01-01

    This Thesis presents experiments performed on the high-frequency conductivity of materials in high magnetic fields. The angle dependence of resonances measured in the millimetre-wave absorption is studied using a rotating resonant cavity system, and the frequency dependence is measured using transmission techniques and a tuneable resonant cavity. Chapter 1 introduces the materials. These include the crystalline organic metals, the layered superconductor Sr sub 2 RUO sub 4 and the quantum Ising ferromagnet LiHoF sub 4. In Chapters 2 and 3, the necessary physics and experimental techniques for their investigation are outlined. Chapters 4 to 6 present measurements of cyclotron resonance in layered materials. Chapter 4 describes several models for the origin of cyclotron resonance harmonics, and describes the first definite measurement of the harmonics of a cyclotron resonance in an organic molecular metal, namely beta sup - (BEDT-TTF) sub 2 SF sub 5 CH sub 2 CF sub 2 SO sub 3. The angle dependence of the field p...

  17. A polarisation modulation scheme for measuring vacuum magnetic birefringence with static fields

    CERN Document Server

    Zavattini, G; Ejlli, A; Ruoso, G

    2016-01-01

    A novel polarisation modulation scheme for polarimeters based on Fabry-Perot cavities is presented. The application to the proposed HERA-X experiment aiming to measuring the magnetic birefringence of vacuum with the HERA superconducting magnets is discussed.

  18. A polarisation modulation scheme for measuring vacuum magnetic birefringence with static fields

    Energy Technology Data Exchange (ETDEWEB)

    Zavattini, G.; Ejlli, A. [Universita di Ferrara, Dipt. di Fisica e Scienze della Terra (Italy); INFN, Sezione di Ferrara (Italy); Della Valle, F. [Universita di Trieste, Dipt. di Fisica, Trieste (Italy); INFN, Sezione di Trieste, TS (Italy); Ruoso, G. [INFN, Lab. Nazionali di Legnaro (Italy)

    2016-05-15

    A novel polarisation modulation scheme for polarimeters based on Fabry-Perot cavities is presented. The application to the measurement of the magnetic birefringence of vacuum with the HERA superconducting magnets in the ALPS-II configuration is discussed. (orig.)

  19. Monte Carlo study of the influence of magnetic field on energy measurements in calorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Abramov, V.V. [Institute for High Energy Physics (IHEP), Protvino (Russian Federation)

    1996-05-11

    The influence of magnetic field on energy measurements in calorimeters is studied by Monte Carlo methods. It is shown that magnetic field influence depends on type of incident particles and on material and thickness of absorber plates. (orig.).

  20. Monte Carlo study of the influence of magnetic field on energy measurements in calorimeters

    Science.gov (United States)

    Abramov, V. V.

    1996-02-01

    The influence of magnetic field on energy measurements in calorimeters is studied by Monte Carlo methods. It is shown that magnetic field influence depends on type of incident particles and on material and thickness of absorber plates.

  1. ³¹P-magnetization transfer magnetic resonance spectroscopy measurements of in vivo metabolism.

    Science.gov (United States)

    Befroy, Douglas E; Rothman, Douglas L; Petersen, Kitt Falk; Shulman, Gerald I

    2012-11-01

    Magnetic resonance spectroscopy offers a broad range of noninvasive analytical methods for investigating metabolism in vivo. Of these, the magnetization-transfer (MT) techniques permit the estimation of the unidirectional fluxes associated with metabolic exchange reactions. Phosphorus (³¹P) MT measurements can be used to examine the bioenergetic reactions of the creatine-kinase system and the ATP synthesis/hydrolysis cycle. Observations from our group and others suggest that the inorganic phosphate (P(i)) → ATP flux in skeletal muscle may be modulated by certain conditions, including aging, insulin resistance, and diabetes, and may reflect inherent alterations in mitochondrial metabolism. However, such effects on the P(i) → ATP flux are not universally observed under conditions in which mitochondrial function, assessed by other techniques, is impaired, and recent articles have raised concerns about the absolute magnitude of the measured reaction rates. As the application of ³¹P-MT techniques becomes more widespread, this article reviews the methodology and outlines our experience with its implementation in a variety of models in vivo. Also discussed are potential limitations of the technique, complementary methods for assessing oxidative metabolism, and whether the P(i) → ATP flux is a viable biomarker of metabolic function in vivo.

  2. Stress dependent vector magnetic properties in electrical steel

    Energy Technology Data Exchange (ETDEWEB)

    Ktena, Aphrodite, E-mail: aktena@teihal.gr [Department of Electrical Engineering, TEI of Chalkida, Psachna, Evia 34400 (Greece); Davino, Daniele; Visone, Ciro [Engineering Department, University of Sannio (Italy); Hristoforou, Evangelos [Laboratory of Metallurgy, National Technical University of Athens (Greece)

    2014-02-15

    The dependence of macroscopic magnetic properties on applied and residual stresses is promising for development of new magnetic non-destructive evaluation techniques in ferrous materials. The reliability of AC magnetometry, in determining the effect of strain on magnetic macroscopic parameters, is evaluated against scalar and vector Vibrating Sample Magnetometer measurements on strained electrical steel samples after unloading. Hysteresis loops have been measured at 0°, 30°, 45°, 60° and 90° to the direction of the applied stress. Vector magnetic properties reveal a stress-related anisotropy component, which increases with strain and deteriorates after fracture. The effect of residual stress on the saturation and remanent magnetization, as well as the differential susceptibility, is discussed with respect to data from AC magnetometry at 0.1 Hz. The results of the latter are representative of the magnetic configuration of the material under test and make it a promising candidate for NDE applications in steels.

  3. Anisotropically structured magnetic aerogel monoliths

    Science.gov (United States)

    Heiligtag, Florian J.; Airaghi Leccardi, Marta J. I.; Erdem, Derya; Süess, Martin J.; Niederberger, Markus

    2014-10-01

    Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture.Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture. Electronic supplementary information (ESI) available: Digital photographs of dispersions and gels with different water-to-ethanol ratios; magnetic measurements of an anatase aerogel containing 0.25 mol% Fe3O4 nanoparticles; XRD patterns of the iron oxide and

  4. Biosensor based on measurements of the clustering dynamics of magnetic particles

    DEFF Research Database (Denmark)

    2014-01-01

    Disclosed herein is a biosensor for optical detection of Brownian relaxation dynamics of magnetic particles measured by light transmission. The magnetic particles can be functionalized with biological ligands for the detection of target analytes in a sample.......Disclosed herein is a biosensor for optical detection of Brownian relaxation dynamics of magnetic particles measured by light transmission. The magnetic particles can be functionalized with biological ligands for the detection of target analytes in a sample....

  5. INTERPRETING MAGNETIC VARIANCE ANISOTROPY MEASUREMENTS IN THE SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    TenBarge, J. M.; Klein, K. G.; Howes, G. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA (United States); Podesta, J. J., E-mail: jason-tenbarge@uiowa.edu [Space Science Institute, Boulder, CO (United States)

    2012-07-10

    The magnetic variance anisotropy (A{sub m}) of the solar wind has been used widely as a method to identify the nature of solar wind turbulent fluctuations; however, a thorough discussion of the meaning and interpretation of the A{sub m} has not appeared in the literature. This paper explores the implications and limitations of using the A{sub m} as a method for constraining the solar wind fluctuation mode composition and presents a more informative method for interpreting spacecraft data. The paper also compares predictions of the A{sub m} from linear theory to nonlinear turbulence simulations and solar wind measurements. In both cases, linear theory compares well and suggests that the solar wind for the interval studied is dominantly Alfvenic in the inertial and dissipation ranges to scales of k{rho}{sub i} {approx_equal} 5.

  6. Experimental measurements of ultrasonic propagation velocity and attenuation in a magnetic fluid.

    Science.gov (United States)

    Motozawa, M; Iizuka, Y; Sawada, T

    2008-05-21

    The ultrasonic propagation velocity and attenuation in a magnetic fluid subjected to magnetic field are measured precisely. Various characteristic properties of ultrasonic propagation in magnetic fluid such as hysteresis and anisotropy are observed. These results show that the ultrasonic propagation velocity and attenuation are dependent upon the intensity and the length of time for which the magnetic field is applied. When the magnetic field is applied, some of the magnetic particles in the magnetic fluid form clustering structures that influence ultrasonic propagation in a magnetic fluid. Our results indicate that the inner structure of a magnetic fluid can be analysed experimentally and we discuss the application of this non-contact inspection of the clustering structures in a magnetic fluid by ultrasonic techniques.

  7. LIF Diagnostic for Measuring Beam-Transport Magnetic Fields

    Science.gov (United States)

    Jones, T. G.; Hinshelwood, D. D.; Neri, J. M.; Ottinger, P. F.; Noonan, W. A.

    1997-11-01

    A novel, spatially-resolved diagnostic is being developed to measure magnetic fields associated with intense ion beam propagation through a low-pressure gas, as is envisioned for light ion-driven ICF. The diagnostic technique uses laser-induced fluorescence (LIF) spectroscopy, and can be varied to measure either small or large fields. Small fields, as expected in ballistic transport with solenoidal lens focusing using ~ 1 Torr gas, produce Zeeman shifts, Δ λ_Z, smaller than the transition linewidth, Δ λ. High sensitivity to measure these shifts is achieved by a variation on the Babcock technique.^1 Large fields, as expected in self-pinched transport using 1--100 mTorr gas, produce Δ λZ larger than Δ λ. These Δ λZ will be resolved using an etalon as a narrowband, high-throughput optical filter. Available results from benchtop experiments using calibrated B-fields for both the small- and large-field techniques, and progress in fielding this diagnostic on the Gamble-II accelerator for beam-transport studies will be presented. Work supported by DOE through Sandia National Laboratories. ^ National Research Council Research Associate. ^ Present address University of Maryland, College Park, MD. ^1 W.A. Noonan, et al., Rev. Sci. Instrum. 68, 1032 (1997).

  8. Investigation of dissipative forces near macroscopic media

    Energy Technology Data Exchange (ETDEWEB)

    Becker, R.S.

    1982-12-01

    The interaction of classical charged particles with the fields they induce in macroscopic dielectric media is investigated. For 10- to 1000-eV electrons, the angular perturbation of the trajectory by the image potential for surface impact parameters of 50 to 100 A is shown to be of the order of 0.001 rads over a distance of 100 A. The energy loss incurred by low-energy particles due to collective excitations such as surface plasmons is shown to be observable with a transition probability of 0.01 to 0.001 (Becker, et al., 1981b). The dispersion of real surface plasmon modes in planar and cylindrical geometries is discussed and is derived for pinhole geometry described in terms of a single-sheeted hyperboloid of revolution. An experimental apparatus for the measurement of collective losses for medium-energy electrons translating close to a dielectric surface is described and discussed. Data showing such losses at electron energies of 500 to 900 eV in silver foils containing many small apertures are presented and shown to be in good agreement with classical stopping power calculations and quantum mechanical calculations carried out in the low-velocity limit. The data and calculations are compared and contrasted with earlier transmission and reflection measurements, and the course of further investigation is discussed.

  9. Macroscopic transport by synthetic molecular machines

    NARCIS (Netherlands)

    Berna, J; Leigh, DA; Lubomska, M; Mendoza, SM; Perez, EM; Rudolf, P; Teobaldi, G; Zerbetto, F

    2005-01-01

    Nature uses molecular motors and machines in virtually every significant biological process, but demonstrating that simpler artificial structures operating through the same gross mechanisms can be interfaced with - and perform physical tasks in - the macroscopic world represents a significant hurdle

  10. Measurement of the magnetic field of small magnets with a smartphone: a very economical laboratory practice for introductory physics courses

    Science.gov (United States)

    Arribas, Enrique; Escobar, Isabel; Suarez, Carmen P.; Najera, Alberto; Beléndez, Augusto

    2015-11-01

    In this work, we propose an inexpensive laboratory practice for an introductory physics course laboratory for any grade of science and engineering study. This practice was very well received by our students, where a smartphone (iOS, Android, or Windows) is used together with mini magnets (similar to those used on refrigerator doors), a 20 cm long school rule, a paper, and a free application (app) that needs to be downloaded and installed that measures magnetic fields using the smartphone’s magnetic field sensor or magnetometer. The apps we have used are: Magnetometer (iOS), Magnetometer Metal Detector, and Physics Toolbox Magnetometer (Android). Nothing else is needed. Cost of this practice: free. The main purpose of the practice is that students determine the dependence of the component x of the magnetic field produced by different magnets (including ring magnets and sphere magnets). We obtained that the dependency of the magnetic field with the distance is of the form x-3, in total agreement with the theoretical analysis. The secondary objective is to apply the technique of least squares fit to obtain this exponent and the magnetic moment of the magnets, with the corresponding absolute error.

  11. Torque analysis and measurements of a permanent magnet type Eddy current brake with a Halbach magnet array based on analytical magnetic field calculations

    Science.gov (United States)

    Park, Min-Gyu; Choi, Jang-Young; Shin, Hyeon-Jae; Jang, Seok-Myeong

    2014-05-01

    This paper presents the torque analysis and measurements of a permanent magnet (PM) type eddy current brake (ECB) with a Halbach magnet array based on analytical magnetic field calculations. On the basis of a magnetic vector potential and using a two-dimensional (2D) polar coordinate system, the analytical solution for magnetic flux density, including the eddy current reaction is evaluated. Based on these solutions, the magnetic torque is also determined analytically. A 2D finite element analysis is employed to validate the method used. Practical issues in the analytical study of the PM type ECBs, such as the maximum braking torque, the required rotor speed, and the segment-dependent, are fully discussed. Finally, the braking torque as a function of the rotor speed is measured to verify the results of the analytical study.

  12. Assessments of macroscopicity for quantum optical states

    DEFF Research Database (Denmark)

    Laghaout, Amine; Neergaard-Nielsen, Jonas Schou; Andersen, Ulrik Lund

    2015-01-01

    With the slow but constant progress in the coherent control of quantum systems, it is now possible to create large quantum superpositions. There has therefore been an increased interest in quantifying any claims of macroscopicity. We attempt here to motivate three criteria which we believe should...... enter in the assessment of macroscopic quantumness: The number of quantum fluctuation photons, the purity of the states, and the ease with which the branches making up the state can be distinguished. © 2014....

  13. Quantum Bell Inequalities from Macroscopic Locality

    CERN Document Server

    Yang, Tzyh Haur; Sheridan, Lana; Scarani, Valerio

    2010-01-01

    We propose a method to generate analytical quantum Bell inequalities based on the principle of Macroscopic Locality. By imposing locality over binary processings of virtual macroscopic intensities, we establish a correspondence between Bell inequalities and quantum Bell inequalities in bipartite scenarios with dichotomic observables. We discuss how to improve the latter approximation and how to extend our ideas to scenarios with more than two outcomes per setting.

  14. Chip-Based Measurements of Brownian Relaxation of Magnetic Beads Using a Planar Hall Effect Magnetic Field Sensor

    Science.gov (United States)

    Østerberg, Frederik W.; Dalslet, Bjarke T.; Snakenborg, Detlef; Johansson, Christer; Hansen, Mikkel F.

    2010-12-01

    We present a simple `click-on' fluidic system with integrated electrical contacts, which is suited for electrical measurements on chips in microfluidic systems. We show that microscopic magnetic field sensors based on the planar Hall effect can be used for detecting the complex magnetic response using only the self-field arising from the bias current applied to the sensors as excitation field. We present measurements on a suspension of magnetic beads with a nominal diameter of 250 nm vs. temperature and find that the observations are consistent with the Cole-Cole model for Brownian relaxation with a constant hydrodynamic bead diameter when the temperature dependence of the viscosity of water is taken into account. These measurements demonstrate the feasibility of performing measurements of the Brownian relaxation response in a lab-on-a-chip system and constitute the first step towards an integrated biosensor based on the detection of the dynamic response of magnetic beads.

  15. Forecasting auroras from regional and global magnetic field measurements

    Science.gov (United States)

    Kauristie, Kirsti; Myllys, Minna; Partamies, Noora; Viljanen, Ari; Peitso, Pyry; Juusola, Liisa; Ahmadzai, Shabana; Singh, Vikramjit; Keil, Ralf; Martinez, Unai; Luginin, Alexej; Glover, Alexi; Navarro, Vicente; Raita, Tero

    2016-06-01

    We use the connection between auroral sightings and rapid geomagnetic field variations in a concept for a Regional Auroral Forecast (RAF) service. The service is based on statistical relationships between near-real-time alerts issued by the NOAA Space Weather Prediction Center and magnetic time derivative (dB/dt) values measured by five MIRACLE magnetometer stations located in Finland at auroral and sub-auroral latitudes. Our database contains NOAA alerts and dB/dt observations from the years 2002-2012. These data are used to create a set of conditional probabilities, which tell the service user when the probability of seeing auroras exceeds the average conditions in Fennoscandia during the coming 0-12 h. Favourable conditions for auroral displays are associated with ground magnetic field time derivative values (dB/dt) exceeding certain latitude-dependent threshold values. Our statistical analyses reveal that the probabilities of recording dB/dt exceeding the thresholds stay below 50 % after NOAA alerts on X-ray bursts or on energetic particle flux enhancements. Therefore, those alerts are not very useful for auroral forecasts if we want to keep the number of false alarms low. However, NOAA alerts on global geomagnetic storms (characterized with Kp values > 4) enable probability estimates of > 50 % with lead times of 3-12 h. RAF forecasts thus rely heavily on the well-known fact that bright auroras appear during geomagnetic storms. The additional new piece of information which RAF brings to the previous picture is the knowledge on typical storm durations at different latitudes. For example, the service users south of the Arctic Circle will learn that after a NOAA ALTK06 issuance in night, auroral spotting should be done within 12 h after the alert, while at higher latitudes conditions can remain favourable during the next night.

  16. Three-dimensional Fe3O4-graphene macroscopic composites for arsenic and arsenate removal.

    Science.gov (United States)

    Guo, Liangqia; Ye, Peirong; Wang, Jing; Fu, Fengfu; Wu, Zujian

    2015-11-15

    3D graphene macroscopic gel synthesized via self-assembly of GO nanosheets under basic conditions at low temperature is modified with polydopamine and Fe3O4 nanoparticles. The modification of polydopamine can not only strengthen the 3D graphene-based macroscopic architecture but also enhance the loadage and binding ability of Fe3O4 nanoparticles. The synthesized 3D Fe3O4-graphene macroscopic composites are characterized by SEM, XRD, XPS, BET, Raman and magnetic property and used as a versatile adsorbent for sub-ppm concentration of As(III) and As(V) removal from aqueous solutions. The experimental results suggest that the synthesized 3D Fe3O4-graphene macroscopic composites are promising for treating low concentration of arsenic contaminated water. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. A METHODOLOGY TO INTEGRATE MAGNETIC RESONANCE AND ACOUSTIC MEASUREMENTS FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Jorge O. Parra; Chris L. Hackert; Lorna L. Wilson

    2002-09-20

    The work reported herein represents the third year of development efforts on a methodology to interpret magnetic resonance and acoustic measurements for reservoir characterization. In this last phase of the project we characterize a vuggy carbonate aquifer in the Hillsboro Basin, Palm Beach County, South Florida, using two data sets--the first generated by velocity tomography and the second generated by reflection tomography. First, we integrate optical macroscopic (OM), scanning electron microscope (SEM) and x-ray computed tomography (CT) images, as well as petrography, as a first step in characterizing the aquifer pore system. This pore scale integration provides information with which to evaluate nuclear magnetic resonance (NMR) well log signatures for NMR well log calibration, interpret ultrasonic data, and characterize flow units at the field scale between two wells in the aquifer. Saturated and desaturated NMR core measurements estimate the irreducible water in the rock and the variable T{sub 2} cut-offs for the NMR well log calibration. These measurements establish empirical equations to extract permeability from NMR well logs. Velocity and NMR-derived permeability and porosity relationships integrated with velocity tomography (based on crosswell seismic measurements recorded between two wells 100 m apart) capture two flow units that are supported with pore scale integration results. Next, we establish a more detailed picture of the complex aquifer pore structures and the critical role they play in water movement, which aids in our ability to characterize not only carbonate aquifers, but reservoirs in general. We analyze petrography and cores to reveal relationships between the rock physical properties that control the compressional and shear wave velocities of the formation. A digital thin section analysis provides the pore size distributions of the rock matrix, which allows us to relate pore structure to permeability and to characterize flow units at the

  18. Measurement system of alternating magnetic properties under DC-biased field

    CERN Document Server

    Enokizono, M

    2000-01-01

    This paper presents magnetic properties under DC-biased magnetization of a grain-oriented silicon steel sheet 30Z. We have practised the measurement of DC-biased flux density by using flux meter directly. The DC-biased magnetic properties have been made clear in this experimental approach.

  19. Estimate of Coronal Magnetic Field Strength Using Plasmoid Acceleration Measurement

    Science.gov (United States)

    Choe, G.; Lee, K.; Jang, M.

    2010-12-01

    A method of estimating the lower bound of coronal magnetic field strength in the neighborhood of an ejecting plasmoid is presented. Based on the assumption that the plasma ejecta is within a magnetic island, an analytical expression for the force acting on the ejecta is derived. A rather simple calculation shows that the vertical force acting on a cylinder-like volume, whose lateral surface is a flux surface and whose magnetic axis is parallel to the horizontal, is just the difference in total pressure (magnetic pressure plus plasma pressure) below and above the volume. The method is applied to a limb coronal mass ejection event, and a lower bound of the magnetic field strength just below the CME core is estimated. The method is expected to provide useful information on the strength of reconnecting magnetic field if applied to X-ray plasma ejecta.

  20. Simulation of Current Measurement Using Magnetic Sensor Arrays and Its Error Model

    Institute of Scientific and Technical Information of China (English)

    WANGJing; YAOJian-jun; WANGJian-hua

    2004-01-01

    Magnetic sensor arrays are proposed to measure electric current in a non-contac tway. In order to achieve higher accuracy, signal processing techniques for magnetic sensor arrays are utilized. Simulation techniques are necessary to study the factors influencing the accuracy of current measurement. This paper presents a simulation method to estimate the impact of sensing area and position of sensors on the accuracy of current measurement. Several error models are built up to support computer-aided design of magnetic sensor arrays.

  1. Distributivity breaking and macroscopic quantum games

    CERN Document Server

    Grib, A A; Parfionov, G N; Starkov, K A

    2005-01-01

    Examples of games between two partners with mixed strategies, calculated by the use of the probability amplitude as some vector in Hilbert space are given. The games are macroscopic, no microscopic quantum agent is supposed. The reason for the use of the quantum formalism is in breaking of the distributivity property for the lattice of yes-no questions arising due to the special rules of games. The rules of the games suppose two parts: the preparation and measurement. In the first part due to use of the quantum logical orthocomplemented non-distributive lattice the partners freely choose the wave functions as descriptions of their strategies. The second part consists of classical games described by Boolean sublattices of the initial non-Boolean lattice with same strategies which were chosen in the first part. Examples of games for spin one half are given. New Nash equilibria are found for some cases. Heisenberg uncertainty relations without the Planck constant are written for the "spin one half game".

  2. On-chip measurement of the Brownian relaxation frequency of magnetic beads using magnetic tunneling junctions

    DEFF Research Database (Denmark)

    Donolato, M.; Sogne, E.; Dalslet, Bjarke Thomas

    2011-01-01

    We demonstrate the detection of the Brownian relaxation frequency of 250 nm diameter magnetic beads using a lab-on-chip platform based on current lines for exciting the beads with alternating magnetic fields and highly sensitive magnetic tunnel junction (MTJ) sensors with a superparamagnetic free...

  3. A Novel Device for the Measurement of the Mechanical and Magnetic Axes of Superconducting Magnet Assemblies for Accelerators

    CERN Document Server

    Aznar, S; Fischer, F; Galbraith, Peter; García-Pérez, J; Goy, S; Mermillod, N; Peiro, G; Patti, G; Rathjen, C

    2002-01-01

    In the context of the LHC superconducting magnet production, especially for dipoles and quadrupoles due to their complexity, it is foreseen to perform acceptance tests, at an early production stage, to detect possible significant deviations from the design values. The knowledge of the magnetic field geometry is very important, especially for the main magnets. In order to get this information a new device has been conceived that measures the magnets at room temperature during different stages of construction. This device incorporates a sensitive measuring probe and an efficient data acquisition system because the coils are only powered at about 10-5 of the nominal D.C. current. It is dedicated to Quadrupole and Dipole (by using Quadrupole-Configured Dipole (QCD) transformation) magnets, but is also easily adaptable to higher order magnets (n = 3, 4 and 5) by specific orientation of the search coils. It is equipped with magnetic sensors (4 fixed tangential coils and AC excitation current for the magnet) and p...

  4. A compact permanent-magnet system for measuring magnetic circular dichroism in resonant inelastic soft X-ray scattering.

    Science.gov (United States)

    Miyawaki, Jun; Suga, Shigemasa; Fujiwara, Hidenori; Niwa, Hideharu; Kiuchi, Hisao; Harada, Yoshihisa

    2017-03-01

    A compact and portable magnet system for measuring magnetic dichroism in resonant inelastic soft X-ray scattering (SX-RIXS) has been developed at the beamline BL07LSU in SPring-8. A magnetic circuit composed of Nd-Fe-B permanent magnets, which realised ∼0.25 T at the center of an 11 mm gap, was rotatable around the axis perpendicular to the X-ray scattering plane. Using the system, a SX-RIXS spectrum was obtained under the application of the magnetic field at an angle parallel, nearly 45° or perpendicular to the incident X-rays. A dedicated sample stage was also designed to be as compact as possible, making it possible to perform SX-RIXS measurements at arbitrary incident angles by rotating the sample stage in the gap between the magnetic poles. This system enables facile studies of magnetic dichroism in SX-RIXS for various experimental geometries of the sample and the magnetic field. A brief demonstration of the application is presented.

  5. Design and realization of a two-dimensional spatial magnetic field mapping apparatus to measure magnetic fields of metamaterials

    Science.gov (United States)

    Jiang, Quan; Zhou, Xiao Yang; Chin, Jessie Yao; Cui, Tie Jun

    2011-07-01

    The two-dimensional (2D) spatial electric-field mapping apparatus [Opt. Express 14, 8694 (2006)] plays an important role in experiments involving metamaterials, such as the verification of free-space and ground-plane invisibility cloaks. However, such an apparatus is valid only for the transverse-electric (TE) mode and is invalid for the transverse-magnetic (TM) mode, as it requires perfectly magnetic conducting (PMC) planes, which do not exist in nature. In this paper, we propose a 2D spatial magnetic-field mapping apparatus based on artificial magnetic conductor (AMC) plates. The AMC structure is designed using periodically perfectly electrical conducting patches with a sub-wavelength size on a dielectric substrate backed with the ground plane, which can simulate a PMC plane. Using two parallel PMC plates to form a TM-wave planar waveguide, we realize the 2D spatial magnetic-field mapping apparatus in order to measure the external and internal magnetic fields of metamaterials. Two types of excitations, a plane-wave source and a magnetic dipole, are used to feed the system. In order to validate the performance of the magnetic-field mapper, two gradient-index metamaterial lenses are measured, and the experimental results are in good agreement with the full-wave simulations.

  6. Vector Magnetic Field Measurement of NOAA AR 10197

    Institute of Scientific and Technical Information of China (English)

    Hong-Fei Liang; Hai-Juan Zhao; Fu-Yuan Xiang

    2006-01-01

    A set of two-dimensional Stokes spectral data of NOAA AR 10197 obtained by the Solar Stokes Spectral Telescope (S3T) at the Yunnan Observatory are qualitatively analyzed.The three components of the vector magnetic field, the strength H, inclination γ and azimuth x, are derived. Based on the three components, we contour the distributions of the longitudinal magnetic field and transverse magnetic field. The active region (AR) has two different magnetic polarities apparent in the longitudinal magnetic map due to projection effect. There is a basic agreement on the longitudinal magnetic fields between the S3T and SOHO/MDI magnetograms, with a correlation coefficient ρBl = 0.911. The transverse magnetic field of the AR has a radial distribution from a center located in the southwest of the AR. It is also found that the transverse magnetic fields obtained by Huairou Solar Observing Station (HRSOS) have a similar radial distribution. The distributions of transverse magnetic field obtained by S3T and HRSOS have correlation coefficients, ρAzimu = 0.86 and ρBt = 0.883,in regard to the azimuthal angle and intensity.

  7. Integrated On-line Instrumentation System of Magnetic Properties Measurement

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A portable microcomputer-controlled inspection system has been developed for detection of mag netic properties of soft magnetic materials. It incorporates custom designed software for control of the magnetic field during operation such as demagnetization, field sweeping, and for data logging and analysis. Results are recorded using a 12-bit analog to digital converter and are then stored on disk. The magnetic hysteresis loop and Barkhausen noise data can be converted into important magnetic parameters:, coecivity, remanence, and hysteresis loss, Barkhausen ampli tude, and Barkhausen noise energy. This system incorporated with the magnetostriction, and magnetoacoustic emission, is then related with the nondestructive detection of material degra dation.

  8. Measurement of Magnetization Curve and Magnetic Relaxation for 2H-NbSe2 Crystals

    Institute of Scientific and Technical Information of China (English)

    Zhang Ning; Liu Hai-lin; Yu Zhu-xing; Xiong Rui; Shi Jing

    2004-01-01

    The characteristics of electronic transport properties: behaviors of magnetization curve and magnetic relaxation of a typical normal superconductor 2H-NbSe2 are investigated. The results show that TCand ΔTC of the samples are 7.2,0.18 K, indicating that superconducting energy gap at zero temperature is 1.1 meV. No fish tail shape is found in the magnetization curves at several temperatures. The relationship between remnant magnetic moment and time reveals that the magnetic flux creep of the sample agrees with the Kim-Anderson thermal activation model with the relaxation rate S=0.000 36 at T=6 K.

  9. Precise Measurement of a Magnetic Field Generated by the Electromagnetic Flux Compression Technique

    CERN Document Server

    Nakamura, D; Matsuda, Y H; Takeyama, S

    2013-01-01

    The precision of the values of a magnetic field generated by electromagnetic flux compression was investigated in ultra-high magnetic fields of up to 700 T. In an attempt to calibrate the magnetic field measured by pickup coils, precise Faraday rotation (FR) measurements were conducted on optical (quartz and crown) glasses. A discernible "turn-around" phenomenon was observed in the FR signal as well as the pickup coils before the end of a liner implosion. We found that the magnetic field measured by pickup coils should be corrected by taking into account the high-frequency response of the signal transmission line. Near the peak magnetic field, however, the pickup coils failed to provide reliable values, leaving the FR measurement as the only method to precisely measure an extremely high magnetic fields.

  10. Precise measurement of a magnetic field generated by the electromagnetic flux compression technique.

    Science.gov (United States)

    Nakamura, D; Sawabe, H; Matsuda, Y H; Takeyama, S

    2013-04-01

    The precision of the values of a magnetic field generated by electromagnetic flux compression was investigated in ultra-high magnetic fields of up to 700 T. In an attempt to calibrate the magnetic field measured by pickup coils, precise Faraday rotation (FR) measurements were conducted on optical (quartz and crown) glasses. A discernible "turn-around" phenomenon was observed in the FR signal as well as the pickup coils before the end of a liner implosion. We found that the magnetic field measured by pickup coils should be corrected by taking into account the high-frequency response of the signal transmission line. Near the peak magnetic field, however, the pickup coils failed to provide reliable values, leaving the FR measurement as the only method to precisely measure extremely high magnetic fields.

  11. Power and energy relations for macroscopic dipolar continua derived from the microscopic Maxwell equations

    CERN Document Server

    Yaghjian, Arthur D

    2015-01-01

    Positive semi-definite expressions for the macroscopic energy density in passive, spatially nondispersive dipolar continua are derived from the underlying microscopic Maxwellian equations satisfied by discrete bound dipolar molecules or inclusions of the material or metamaterial continua. The microscopic derivation reveals two distinct positive semi-definite macroscopic energy expressions, one that applies to diamagnetic continua and another that applies to nondiamagnetic continua (for example, paramagnetic or ferro(i)magnetic material). The diamagnetic dipoles are unconditionally passive in that their Amperian magnetic dipole moments are zero in the absence of applied fields. The analysis of the nondiamagnetic continua, which are defined in terms of magnetization caused by the alignment of randomly oriented pre-existing Amperian magnetic dipole moments that dominate any induced diamagnetic magnetization, is greatly simplified by first proving that the microscopic power equations for rotating pre-existing Amp...

  12. Evaluation of left ventricular volumes measured by magnetic resonance imaging

    DEFF Research Database (Denmark)

    Møgelvang, J; Thomsen, C; Mehlsen, J

    1986-01-01

    Left ventricular end-diastolic and end-systolic volumes were determined in 17 patients with different levels of left ventricular function by magnetic resonance imaging (MRI). A 1.5 Tesla Magnet was used obtaining ECG triggered single and multiple slices. Calculated cardiac outputs were compared...

  13. Read-out electronics for DC squid magnetic measurements

    Science.gov (United States)

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2002-01-01

    Read-out electronics for DC SQUID sensor systems, the read-out electronics incorporating low Johnson noise radio-frequency flux-locked loop circuitry and digital signal processing algorithms in order to improve upon the prior art by a factor of at least ten, thereby alleviating problems caused by magnetic interference when operating DC SQUID sensor systems in magnetically unshielded environments.

  14. Creating an innovative tool to measure Magnet® readiness.

    Science.gov (United States)

    Grant, Susan; Toney, Sharlene; Wilson, Martha; Barrett, Lynda; Kamke, Brooke

    2012-11-01

    Magnet designation has become a highly sought-after credential for hospitals across the United States and internationally who want to distinguish themselves for clinical excellence and employee engagement. This article chronicles how Emory Healthcare, the largest, comprehensive academic healthcare system in Georgia, developed the Magnet Readiness Index™ to assess the status of nursing compared with the standards prior to submission of an application.

  15. Magnetic-field- and pressure-induced quantum phase transition in CsFeCl3 proved via magnetization measurements

    Science.gov (United States)

    Kurita, Nobuyuki; Tanaka, Hidekazu

    2016-09-01

    We have performed magnetization measurements of the gapped quantum magnet CsFeCl3 at temperatures (T ) down to 0.5 K at ambient pressure and down to 1.8 K at hydrostatic pressures (P ) of up to 1.5 GPa. The lower-field (H ) phase boundary of the field-induced ordered phase at ambient pressure is found to follow the power-law behavior expressed by the formula HN(T ) -Hc∝TNϕ . The application of pressure extends the phase boundary to both a lower field and higher temperature. Above the critical pressure Pc˜0.9 GPa, the transition field HN associated with the excitation gap becomes zero, and a signature of the magnetic phase transition is found in the T dependence of magnetization in a very low applied field. This suggests that CsFeCl3 exhibits a pressure-induced magnetic phase transition at Pc.

  16. Comparison of magnetic field meters used for Elf exposure measurement

    Energy Technology Data Exchange (ETDEWEB)

    Magne, I. [Electricite de France (EDF/RD), 77 - Moret sur Loing (France); Azoulay, A. [Supelec, 91 - Gif sur Yvette (France); Lambrozo, J.; Souques, M. [Gaz de France (EDF/GDF), SEM, 75 - Paris (France)

    2006-07-01

    Objective The question of the biological effects of E.L.F. electromagnetic fields (50/60 Hz) has lead to many experimental and epidemiological works, in occupational exposure and in residential exposure. One of the main difficulties is to integrate the maximum of information about the environmental exposures during the everyday life without limitation to the exposure of the home. The objective of this study is to analyse experimentally the metrology associated with human exposure to 50 Hz magnetic field, in the optic of a study of the French population exposure. Method 4 meters were tested: the E.M.D.E.X. II, currently used in epidemiological studies, the E.M.D.E.X. L.I.T.E., which is more recent, the H.T.300, an Italian meter, and the F.D.3, which is made by Combinova A calibration was performed with an Helmoltz coil. The immunity of these meters to GSM signal was also tested. The influence of the sample rate was evaluated. Results and conclusion The meter chosen for performing the measurements of the exposure study will be selected in function of the following criteria: - easiness of use - precision - low sample rate - memory size and reliability of data stocking - immunity to GSM perturbations. (authors)

  17. Magnetic Field Measurements Based on Terfenol Coated Photonic Crystal Fibers

    Directory of Open Access Journals (Sweden)

    Carla C. Kato

    2011-11-01

    Full Text Available A magnetic field sensor based on the integration of a high birefringence photonic crystal fiber and a composite material made of Terfenol particles and an epoxy resin is proposed. An in-fiber modal interferometer is assembled by evenly exciting both eigenemodes of the HiBi fiber. Changes in the cavity length as well as the effective refractive index are induced by exposing the sensor head to magnetic fields. The magnetic field sensor has a sensitivity of 0.006 (nm/mT over a range from 0 to 300 mT with a resolution about ±1 mT. A fiber Bragg grating magnetic field sensor is also fabricated and employed to characterize the response of Terfenol composite to the magnetic field.

  18. Magnetic field measurements based on Terfenol coated photonic crystal fibers.

    Science.gov (United States)

    Quintero, Sully M M; Martelli, Cicero; Braga, Arthur M B; Valente, Luiz C G; Kato, Carla C

    2011-01-01

    A magnetic field sensor based on the integration of a high birefringence photonic crystal fiber and a composite material made of Terfenol particles and an epoxy resin is proposed. An in-fiber modal interferometer is assembled by evenly exciting both eigenemodes of the HiBi fiber. Changes in the cavity length as well as the effective refractive index are induced by exposing the sensor head to magnetic fields. The magnetic field sensor has a sensitivity of 0.006 (nm/mT) over a range from 0 to 300 mT with a resolution about ±1 mT. A fiber Bragg grating magnetic field sensor is also fabricated and employed to characterize the response of Terfenol composite to the magnetic field.

  19. Macroscopic electromagnetic response of metamaterials with toroidal resonances

    CERN Document Server

    Savinov, V; Zheludev, N I

    2013-01-01

    Toroidal dipole, first described by Ia. B. Zeldovich [Sov. Phys. JETP 33, 1184 (1957)], is a distinct electromagnetic excitation that differs both from the electric and the magnetic dipoles. It has a number of intriguing properties: static toroidal nuclear dipole is responsible for parity violation in atomic spectra; interactions between static toroidal dipole and oscillating magnetic dipole are claimed to violate Newton's Third Law while non-stationary charge-current configurations involving toroidal multipoles have been predicted to produce vector potential in the absence of electromagnetic fields. Existence of the toroidal response in metamaterials was recently demonstrated and is now a growing field of research. However, no direct analytical link has yet been established between the transmission and reflection of macroscopic electromagnetic media and toroidal dipole excitations. To address this essential gap in electromagnetic theory we have developed an analytical approach linking microscopic and macrosc...

  20. Measurement of magnetic fields produced by a "magnetic deflector" for the removal of electron contamination in radiotherapy.

    Science.gov (United States)

    Damrongkijudom, N; Oborn, B; Butson, M; Rosenfeld, A

    2006-12-01

    Electron contamination generated from interactions of x-rays with components in a medical linear accelerator's head can increase damage to skin and subcutaneous tissue during radiotherapy through increased dose deposition. Skin and subcutaneous dose from high energy x-rays can be reduced using magnetic fields to sweep the electron contamination away from the radiation treatment field. This work is aimed at investigating the magnetic fields generated by an improved magnetic deflector which utilizes Nd2Fe14B magnets. Magnetic field strengths generated by the deflector have been simulated using Vizimag 3.0 magnetic modelling software. The improved deflector has a more uniform magnetic field strength than its predecessor and is optimised to easily fit on a clinical linear accelerator. Experimental measurements of the magnetic field strengths produced have also been performed for comparison. Results show a relatively good match to Vizimag modelling in the central regions of the deflector. Reductions of skin and subcutaneous dose up to 34% of original values were seen for a 20 x 20 cm2 field at 6MV x-ray energy.

  1. The alignment and measurement of the magnetic field for muon counter at BESIII

    CERN Document Server

    Gao, Qing; Li, Chunhua

    2016-01-01

    Based on cosmic ray events taken without magnet filed during summer shutdown, we compare the coordinates of hits in muon counter with the expected interaction point of extrapolated tracks from the inner tracking system. By minimizing the difference, we align the muon counter with the inner tracking system. The muon counter is operating in magnetic return yoke and the magnetic field has never been measured before. The strength of the magnetic field of the muon counter is measured for the first time with $\\mu^+$ and $\\mu^-$ separately. After the alignment and magnetic field measurement, the offsets of hit-position for $\\mu^+$ and $\\mu^-$ are diminished. The alignment and magnetic field measurement are adopted in the latest BESIII offline software system. This makes physics analysis involving muon counter information more reliable.

  2. The quantitative measurement of magnetic moments from phase images of nanoparticles and nanostructures – I. Fundamentals

    DEFF Research Database (Denmark)

    Beleggia, Marco; Kasama, Takeshi; Dunin-Borkowski, Rafal E.

    2010-01-01

    An approach that can be used to measure the magnetic moment of a magnetized nanoparticle or nanostructure from an electron-optical phase image is introduced. The measurement scheme is based on integration of the gradient of the measured phase image within a circular boundary that contains...... the structure of interest. The quantity obtained is found to be directly proportional to the magnetic moment of the particle, with a constant of proportionality that does not depend on the particle's shape or magnetization state. The measurement of magnetic moments from both simulated and experimental phase...... images is demonstrated, and strategies are presented that can be utilized to overcome sources of error associated with, for example, the presence of neighboring magnetic particles and the perturbation of the holographic reference wave...

  3. The quantitative measurement of magnetic moments from phase images of nanoparticles and nanostructures-I. Fundamentals

    Energy Technology Data Exchange (ETDEWEB)

    Beleggia, Marco, E-mail: mb@cen.dtu.dk [Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Kasama, Takeshi; Dunin-Borkowski, Rafal E. [Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2010-04-15

    An approach that can be used to measure the magnetic moment of a magnetized nanoparticle or nanostructure from an electron-optical phase image is introduced. The measurement scheme is based on integration of the gradient of the measured phase image within a circular boundary that contains the structure of interest. The quantity obtained is found to be directly proportional to the magnetic moment of the particle, with a constant of proportionality that does not depend on the particle's shape or magnetization state. The measurement of magnetic moments from both simulated and experimental phase images is demonstrated, and strategies are presented that can be utilized to overcome sources of error associated with, for example, the presence of neighboring magnetic particles and the perturbation of the holographic reference wave.

  4. Smart-Phone Based Magnetic Levitation for Measuring Densities.

    Science.gov (United States)

    Knowlton, Stephanie; Yu, Chu Hsiang; Jain, Nupur; Ghiran, Ionita Calin; Tasoglu, Savas

    2015-01-01

    Magnetic levitation, which uses a magnetic field to suspend objects in a fluid, is a powerful and versatile technology. We develop a compact magnetic levitation platform compatible with a smart-phone to separate micro-objects and estimate the density of the sample based on its levitation height. A 3D printed attachment is mechanically installed over the existing camera unit of a smart-phone. Micro-objects, which may be either spherical or irregular in shape, are suspended in a paramagnetic medium and loaded in a microcapillary tube which is then inserted between two permanent magnets. The micro-objects are levitated and confined in the microcapillary at an equilibrium height dependent on their volumetric mass densities (causing a buoyancy force toward the edge of the microcapillary) and magnetic susceptibilities (causing a magnetic force toward the center of the microcapillary) relative to the suspending medium. The smart-phone camera captures magnified images of the levitating micro-objects through an additional lens positioned between the sample and the camera lens cover. A custom-developed Android application then analyzes these images to determine the levitation height and estimate the density. Using this platform, we were able to separate microspheres with varying densities and calibrate their levitation heights to known densities to develop a technique for precise and accurate density estimation. We have also characterized the magnetic field, the optical imaging capabilities, and the thermal state over time of this platform.

  5. Smart-Phone Based Magnetic Levitation for Measuring Densities.

    Directory of Open Access Journals (Sweden)

    Stephanie Knowlton

    Full Text Available Magnetic levitation, which uses a magnetic field to suspend objects in a fluid, is a powerful and versatile technology. We develop a compact magnetic levitation platform compatible with a smart-phone to separate micro-objects and estimate the density of the sample based on its levitation height. A 3D printed attachment is mechanically installed over the existing camera unit of a smart-phone. Micro-objects, which may be either spherical or irregular in shape, are suspended in a paramagnetic medium and loaded in a microcapillary tube which is then inserted between two permanent magnets. The micro-objects are levitated and confined in the microcapillary at an equilibrium height dependent on their volumetric mass densities (causing a buoyancy force toward the edge of the microcapillary and magnetic susceptibilities (causing a magnetic force toward the center of the microcapillary relative to the suspending medium. The smart-phone camera captures magnified images of the levitating micro-objects through an additional lens positioned between the sample and the camera lens cover. A custom-developed Android application then analyzes these images to determine the levitation height and estimate the density. Using this platform, we were able to separate microspheres with varying densities and calibrate their levitation heights to known densities to develop a technique for precise and accurate density estimation. We have also characterized the magnetic field, the optical imaging capabilities, and the thermal state over time of this platform.

  6. Measurements of magnetic field strength on T Tauri stars

    Science.gov (United States)

    Guenther, Eike W.; Lehmann, Holger; Emerson, James P.; Staude, Jürgen

    1999-01-01

    We have investigated the magnetic field strength of one weak-line and four classical T Tauri stars. The magnetic field strength is derived from the differential change of the equivalent width of photospheric Fe I lines in the presence of a magnetic field, calculated using a full radiative transfer code. The method was successfully tested by applying it to a non-magnetic solar-type star, and to VY Ari which is believed to have a strong magnetic field. For two of the classical T Tauri stars, we find a product of magnetic field strength and filling factor B * f = (2.35+/- 0.15) kG for T Tau, and B * f = (1.1+/- 0.2) kG for LkCa 15. For the classical T Tauri star UX Tau A and the weak-line T Tauri star LkCa 16 the detection is only marginal, indicating magnetic field strengths of the order of 1 kG and possibly of more than 2 kG, respectively. No field could be detected for the classical T Tauri star GW Ori. For the two classical T Tauri stars for which we have detected a field, we find the filling factors to be larger than ~ 0.5, which indicates that the magnetic field covers most of the photosphere. We also show that ignoring a magnetic field can, depending on the lines used, result in errors in effective temperature and underestimates of veiling. Based on observations made with the William Herschel Telescope operated on the island of La Palma by the Royal Greenwich Observatory in the Spanish Observatorio de los Roque de los Muchachos of the Instituto de Astrofisica de Canarias

  7. Macroscopic optical response and photonic bands

    CERN Document Server

    Perez-Huerta, J S; Mendoza, Bernardo S; Mochan, W Luis

    2012-01-01

    We develop a formalism for the calculation of the macroscopic dielectric response of composite systems made of particles of one material embedded periodically within a matrix of another material, each of which is characterized by a well defined dielectric function. The nature of these dielectric functions is arbitrary, and could correspond to dielectric or conducting, transparent or opaque, absorptive and dispersive materials. The geometry of the particles and the Bravais lattice of the composite are also arbitrary. Our formalism goes beyond the longwavelenght approximation as it fully incorporates retardation effects. We test our formalism through the study the propagation of electromagnetic waves in 2D photonic crystals made of periodic arrays of cylindrical holes in a dispersionless dielectric host. Our macroscopic theory yields a spatially dispersive macroscopic response which allows the calculation of the full photonic band structure of the system, as well as the characterization of its normal modes, upo...

  8. Nanoplasmon-enabled macroscopic thermal management

    CERN Document Server

    Jonsson, Gustav Edman; Dmitriev, Alexandre

    2013-01-01

    In numerous applications of energy harvesting via transformation of light into heat the focus recently shifted towards highly absorptive materials featuring nanoplasmons. It is currently established that noble metals-based absorptive plasmonic platforms deliver significant light-capturing capability and can be viewed as super-absorbers of optical radiation. However, direct experimental evidence of plasmon-enabled macroscopic temperature increase that would result from these efficient absorptive properties is scarce. Here we derive a general quantitative method of characterizing light-capturing properties of a given heat-generating absorptive layer by macroscopic thermal imaging. We further monitor macroscopic areas that are homogeneously heated by several degrees with plasmon nanostructures that occupy a mere 8% of the surface, leaving it essentially transparent and evidencing significant heat generation capability of nanoplasmon-enabled light capture. This has a direct bearing to thermophotovoltaics and othe...

  9. Correlation of AC Loss Data from Magnetic Susceptibility Measurements with YBCO Film Quality (Postprint)

    Science.gov (United States)

    2012-02-01

    AFRL-RZ-WP-TP-2012-0100 CORRELATION OF AC LOSS DATA FROM MAGNETIC SUSCEPTIBILITY MEASUREMENTS WITH YBCO FILM QUALITY (POSTPRINT) Paul N...CORRELATION OF AC LOSS DATA FROM MAGNETIC SUSCEPTIBILITY MEASUREMENTS WITH YBCO FILM QUALITY (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT...spreading of the temperature-dependent ac susceptibility curves with increasing applied magnetic field, the quality of the YBCO film generally

  10. Measurement of Magnetic Properties of an Inertial Sensor with a Torsion Balance

    Institute of Scientific and Technical Information of China (English)

    TU Hai-Bo; BAI Yan-Zheng; ZHOU Ze-Bing; LIANG Yu-Rong

    2009-01-01

    @@ A torsion balance is constructed to accurately measure the magnetic properties of the real proof mass of the inertial sensor. The magnetic susceptibility and remnant moment of a titanium proof mass are measured in the first experiment, and further improvements and the potential sensitivity are also discussed. This is significant for choosing the material of the proof mass and investigating the magnetic disturbances acting on the proof mass.

  11. Quench Limit Model and Measurements for Steady State Heat Deposits in LHC Magnets

    CERN Document Server

    Bocian, D; Siemko, A

    2009-01-01

    A quench, transition of a conductor from the superconducting to the normal conducting state, occurs irreversibly in accelerator magnets if one of the three parameters: temperature, magnetic field or current density, exceeds its critical value. The protons lost from the beam and impacting on the vacuum chamber, create a secondary particle shower that deposes its energy in the magnet coil. Energy deposited in the superconductor by these particles can provoke quenches that can be detrimental for the accelerator operation. A network model is developed to study the thermodynamic behavior of the LHC magnets. The results of the heat flow simulation in the main dipole and quadrupole LHC magnets calculated by means of the network model were validated with measurements performed at superfluid helium temperatures in the CERN magnet test facility. A steady state heat flow was introduced in the magnet coil by using a dedicated internal heating apparatus (IHA) installed inside the magnet cold bore. The value of the heat so...

  12. Chip-Based Measurements of Brownian Relaxation of Magnetic Beads Using a Planar Hall Effect Magnetic Field Sensor

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Dalslet, Bjarke Thomas; Snakenborg, Detlef

    2010-01-01

    We present a simple 'click-on' fluidic system with integrated electrical contacts, which is suited for electrical measurements on chips in microfluidic systems. We show that microscopic magnetic field sensors based on the planar Hall effect can be used for detecting the complex magnetic response...... with a constant hydrodynamic bead diameter when the temperature dependence of the viscosity of water is taken into account. These measurements demonstrate the feasibility of performing measurements of the Brownian relaxation response in a lab-on-a-chip system and constitute the first step towards an integrated...... using only the self-field arising from the bias current applied to the sensors as excitation field. We present measurements on a suspension of magnetic beads with a nominal diameter of 250 nm vs. temperature and find that the observations are consistent with the Cole-Cole model for Brownian relaxation...

  13. EXPERIMENTAL MEASUREMENT OF MAGNETIC FIELD IN A NOVEL FLOW CONTROL OF MOLD

    Institute of Scientific and Technical Information of China (English)

    G.J. Xu; D.H. Li; J.C. He

    2002-01-01

    In order to know the distribution of magnetic field in a novel flow control of mold(NFC Mold) and to provide the experimental data for the electromagnetic structuredesign and the analysis of flow control in continuous casting mold, the magnetic fieldin a NFC Mold were measured by Tesla meter of Model CT-3. The method of vectorsynthesis was adopted in the measurement of magnetic fields. The results showed thatthe magnetic field in the NFC Mold was composed of two main magnetic areas thatwere symmetrical. Although there was leaking magnetic flux between the lower surfaceof the upper pole and the upper surface of the lower pole on the sides, it was restrainedby the main magnetic fields effectively. Therefore the NFC Mold was more preferablysatisfied to be used in controlling the molten steel flow in continuous casting mold.

  14. Measuring magnetism in the Milky Way with the Square Kilometre Array

    CERN Document Server

    Haverkorn, Marijke; Carretti, Ettore; Ferriere, Katia; Frick, Peter; Gaensler, Bryan; Heald, George; Johnston-Hollitt, Melanie; Jones, David; Landecker, Tom; Mao, Sui Ann; Noutsos, Aris; Oppermann, Niels; Reich, Wolfgang; Robishaw, Timothy; Scaife, Anna; Schnitzeler, Dominic; Stepanov, Rodion; Sun, Xiaohui; Taylor, Russ

    2015-01-01

    Magnetic fields in the Milky Way are present on a wide variety of sizes and strengths, influencing many processes in the Galactic ecosystem such as star formation, gas dynamics, jets, and evolution of supernova remnants or pulsar wind nebulae. Observation methods are complex and indirect; the most used of these are a grid of rotation measures of unresolved polarized extragalactic sources, and broadband polarimetry of diffuse emission. Current studies of magnetic fields in the Milky Way reveal a global spiral magnetic field with a significant turbulent component; the limited sample of magnetic field measurements in discrete objects such as supernova remnants and HII regions shows a wide variety in field configurations; a few detections of magnetic fields in Young Stellar Object jets have been published; and the magnetic field structure in the Galactic Center is still under debate. The SKA will unravel the 3D structure and configurations of magnetic fields in the Milky Way on sub-parsec to galaxy scales, includ...

  15. Magnetic Property Measurements on Single Wall Carbon Nanotube-Polyimide Composites

    Science.gov (United States)

    Sun, Keun J.; Wincheski, Russell A.; Park, Cheol

    2008-01-01

    Temperature and magnetic field dependent magnetization measurements were performed on polyimide nanocomposite samples, synthesized with various weight percentages of single wall carbon nanotubes. It was found that the magnetization of the composite, normalized to the mass of nanotube material in the sample, decreased with increasing weight percentage of nanotubes. It is possible that the interfacial coupling between the carbon nanotube (CNT) fillers and the polyimide matrix promotes the diamagnetic response from CNTs and reduces the total magnetization of the composite. The coercivity of the samples, believed to originate from the residual magnetic catalyst particles, was enhanced and had a stronger temperature dependence as a result of the composite synthesis. These changes in magnetic properties can form the basis of a new approach to investigate the interfacial properties in the CNT nanocomposites through magnetic property measurements.

  16. Three-dimensional photogrammetric measurement of magnetic field lines in the WEGA stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Drewelow, Peter; Braeuer, Torsten; Otte, Matthias; Wagner, Friedrich; Werner, Andreas [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Wendelsteinstr. 1, D-17491 Greifswald (Germany)

    2009-12-15

    The magnetic confinement of plasmas in fusion experiments can significantly degrade due to perturbations of the magnetic field. A precise analysis of the magnetic field in a stellarator-type experiment utilizes electrons as test particles following the magnetic field line. The usual fluorescent detector for this electron beam limits the provided information to two-dimensional cut views at certain toroidal positions. However, the technique described in this article allows measuring the three-dimensional structure of the magnetic field by means of close-range photogrammetry. After testing and optimizing the main diagnostic components, measurements of the magnetic field lines were accomplished with a spatial resolution of 5 mm. The results agree with numeric calculations, qualifying this technique as an additional tool to investigate magnetic field configurations in a stellarator. For a possible future application, ways are indicated on how to reduce experimental error sources.

  17. Three-dimensional photogrammetric measurement of magnetic field lines in the WEGA stellarator.

    Science.gov (United States)

    Drewelow, Peter; Bräuer, Torsten; Otte, Matthias; Wagner, Friedrich; Werner, Andreas

    2009-12-01

    The magnetic confinement of plasmas in fusion experiments can significantly degrade due to perturbations of the magnetic field. A precise analysis of the magnetic field in a stellarator-type experiment utilizes electrons as test particles following the magnetic field line. The usual fluorescent detector for this electron beam limits the provided information to two-dimensional cut views at certain toroidal positions. However, the technique described in this article allows measuring the three-dimensional structure of the magnetic field by means of close-range photogrammetry. After testing and optimizing the main diagnostic components, measurements of the magnetic field lines were accomplished with a spatial resolution of 5 mm. The results agree with numeric calculations, qualifying this technique as an additional tool to investigate magnetic field configurations in a stellarator. For a possible future application, ways are indicated on how to reduce experimental error sources.

  18. An Orientation Measurement Method Based on Hall-effect Sensors for Permanent Magnet Spherical Actuators with 3D Magnet Array

    Science.gov (United States)

    Yan, Liang; Zhu, Bo; Jiao, Zongxia; Chen, Chin-Yin; Chen, I.-Ming

    2014-10-01

    An orientation measurement method based on Hall-effect sensors is proposed for permanent magnet (PM) spherical actuators with three-dimensional (3D) magnet array. As there is no contact between the measurement system and the rotor, this method could effectively avoid friction torque and additional inertial moment existing in conventional approaches. Curved surface fitting method based on exponential approximation is proposed to formulate the magnetic field distribution in 3D space. The comparison with conventional modeling method shows that it helps to improve the model accuracy. The Hall-effect sensors are distributed around the rotor with PM poles to detect the flux density at different points, and thus the rotor orientation can be computed from the measured results and analytical models. Experiments have been conducted on the developed research prototype of the spherical actuator to validate the accuracy of the analytical equations relating the rotor orientation and the value of magnetic flux density. The experimental results show that the proposed method can measure the rotor orientation precisely, and the measurement accuracy could be improved by the novel 3D magnet array. The study result could be used for real-time motion control of PM spherical actuators.

  19. Study on technology of high-frequency pulsed magnetic field strength measurement.

    Science.gov (United States)

    Chen, Yi-Mei; Liu, Zhi-Peng; Yin, Tao

    2012-01-01

    High-frequency transient weak magnetic field is always involved in researches about biomedical engineering field while common magnetic-field sensors cannot work properly at frequencies as high as MHz. To measure the value of MHz-level weak pulsed magnetic-field strength accurately, this paper designs a measurement and calibration method for pulsed magnetic-field. In this paper, a device made of Nonferromagnetic material was independently designed and applied to pulsed magnetic field measurement. It held an accurately relative position between the magnetic field generating coil and the detecting coil. By applying a sinusoidal pulse to the generator, collecting the induced electromotive force of the detector, the final magnetic field strength was worked out through algorithms written in Matlab according to Faraday's Law. Experiments were carried out for measurement and calibration. Experiments showed that, under good stability and consistency, accurate measurement of magnetic-field strength of a sinepulse magnetic-field can be achieved, with frequency at 0.5, 1, 1.5 MHz and strength level at micro-Tesla. Calibration results carried out a measuring relative error about 2.5%.

  20. Strain measurements in ferromagnetic martensitic Heuslers and magnetization easy axis

    Energy Technology Data Exchange (ETDEWEB)

    Aksoy, Seda; Acet, Mehmet; Wassermann, Eberhard F. [Experimentalphysik, Universitaet Duisburg-Essen, Duisburg (Germany)

    2008-07-01

    The temperature-dependence of strain under constant magnetic-fields is studied in Ni-Mn-X (X:Ga,In,Sn,Sb) and Ni-Mn-In-X (X:Ga,Sn,Sb) polycrystalline ferromagnetic Heusler alloys which undergo a martensitic transformation close to room-temperature. The applied magnetic-field influences the nucleation of martensite so that decreasing the temperature under a magnetic field leads to large length changes between the austenite and martensite states. The length-change within the martensitic state varies with the magnitude of the cooling-field. This is related to the variant-orientation during martensite nucleation. These strain-data provide information on the easy axis of magnetization.

  1. FMR measurements in fire ants: evidence of magnetic material

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, Darci M.S.; Acosta-Avalos, Daniel; El-Jaick, Lea J.; Cunha, Alexandra D.M.; Malheiros, Maria G.; Wajnberg, Eliane [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Linhares, Marilia P. [Centro de Ciencias do Estado, do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    1998-01-01

    Based on the behavioral and the localization of iron-containing tissue fire ants were examined by EPR for magnetic material. Results suggest the presence of magnetite particles. (author) 12 refs., 1 fig.

  2. Quantitative measurements of magnetic polaron binding on acceptors in CdMnTe alloys

    Science.gov (United States)

    Nhung, Tran Hong; Planel, R.

    1983-03-01

    The acceptor binding energy is measured as a function of Temperature and composition in Cd1-x Mnx Te alloys, by time resolved spectroscopy. The Bound magnetic polaron effect is measured and compared with a theory accouting for magnetic saturation and fluctuations.

  3. In vivo magnetic resonance diffusion measurement in the brain of patients with multiple sclerosis

    DEFF Research Database (Denmark)

    Larsson, H B; Thomsen, C; Frederiksen, J;

    1992-01-01

    Measurement of water self-diffusion in the brain in 25 patients with multiple sclerosis was performed by magnetic resonance imaging. Quantitative diffusion measurements were obtained using single spin-echo pulse sequences with pulsed magnetic field gradients of different magnitude. Twenty...

  4. Magnetic measurements of modulator and dispersion sections for the BNL HGFEL

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, L.; Graves, W.S.; Ben-Zvi, I. [Brookhaven National Lab., Upton, NY (United States)] [and others

    1995-12-31

    The Harmonic Generation Free Electron Laser is a high-gain amplifier FEL configured as an optical klystron. It is presently under construction at Brookhaven National Lab. Each of the three superconducting magnet sections (modulator, buncher, radiator) has been built and the magnetic fields have been measured. This paper reports the measurement results and compares them with three-dimensional simulations.

  5. MEASUREMENT OF NASAL FIGURE BY MAGNETIC RESONANCE IMAGING

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective To get the basic data of nasal figure of the Han nationality individuals in Xi'an area and provide for junsprudence and the reconstruction of skull. Methods Nasal height, length, depth and breadth of 313cases in Xi'an area, which had different age and sex, were measured by magnetic resonance imaging (MRI). Results Image of MRI could clearly show the figure of nose and the position we selected were correct and accuracy. The specific data were: Nasal length (male:34. 47±4.29 ~52.20±3.47, female:33. 11±3.33~46. 94±3.83); Nasal height(male: 39.22±3.68~59.49±2.30, female: 33.89±3.95~51.75±3.68); Nasal depth(male: 11.89±1.76~16.68±2.48, female: 10.69±1. 81~16.46±2.04);Nasal breadth(male: 33. 09±3. 83~42. 49±2.72,female:32.00±1.94~38. 86±2.61). So the results were credible. Conclusion The nasal figure of individuals in Xi'an area is different as their different age and sex. It promotes that the influence factors of age and sex must be considered in the facial reconstruction and medico legally reconstructing skull.

  6. Re-creating Gauss's method for non-electrical absolute measurements of magnetic fields and moments

    Science.gov (United States)

    Van Baak, D. A.

    2013-10-01

    In 1832, Gauss made the first absolute measurements of magnetic fields and of magnetic moments in experiments that are straightforward and instructive to replicate. We show, using rare-earth permanent magnets and a variation of Gauss's technique, that the horizontal component of the ambient geomagnetic field, as well as the size of the magnetic moments of such magnets, can be found. The method shows the connection between the SI and cgs emu unit systems for these quantities and permits an absolute realization of the Ampere with considerable precision.

  7. Design and Measurement of Dipole Magnets for CSNS 1.6GeV RCS

    CERN Document Server

    Li, Qing; Kang, Wen; Deng, Chang-dong; Chen, Wan

    2016-01-01

    The Rapid Cycling Synchrotron (RCS) in Chinese Spallation Neutron Source (CSNS) accelerates proton beam from 80Mev to 1.6GeV at a repetition rate of 25Hz. All dipole magnets of RCS are operated at AC with biased DC. Aiming at the properties of these dipole magnets, we take some methods to improve magnetic field quality in the good region and reduce eddy currents in the iron core . In this paper, we would present the process of the magnet design and temperature rise calculation. At the same time, the field measurement results and temperature test of the prototype magnet are also described and discussed.

  8. Magnetic properties of thin Ni films measured by a dc SQUID-based magnetic microscope

    DEFF Research Database (Denmark)

    Snigirev, O.V.; Andreev, K.E.; Tishin, A.M.;

    1997-01-01

    We have applied a scanning HTS (high-temperature superconductor) de SQUID (superconducting quantum interference device) -based magnetic microscope to study the magnetic properties of Au/Ni/Si(100) films in the thickness range from 8 to 200 Angstrom at T = 77 K. A one-domain structure with in-plan...

  9. Reconstruction of conductivity and current density images using only one component of magnetic field measurements.

    Science.gov (United States)

    Seo, Jin Keun; Yoon, Jeong-Rock; Woo, Eung Je; Kwon, Ohin

    2003-09-01

    Magnetic resonance current density imaging (MRCDI) is to provide current density images of a subject using a magnetic resonance imaging (MRI) scanner with a current injection apparatus. The injection current generates a magnetic field that we can measure from MR phase images. We obtain internal current density images from the measured magnetic flux densities via Ampere's law. However, we must rotate the subject to acquire all of the three components of the induced magnetic flux density. This subject rotation is impractical in clinical MRI scanners when the subject is a human body. In this paper, we propose a way to eliminate the requirement of subject rotation by careful mathematical analysis of the MRCDI problem. In our new MRCDI technique, we need to measure only one component of the induced magnetic flux density and reconstruct both cross-sectional conductivity and current density images without any subject rotation.

  10. Tilted Magnetic Levitation Enables Measurement of the Complete Range of Densities of Materials with Low Magnetic Permeability.

    Science.gov (United States)

    Nemiroski, Alex; Soh, Siowling; Kwok, Sen Wai; Yu, Hai-Dong; Whitesides, George M

    2016-02-03

    Magnetic levitation (MagLev) of diamagnetic or weakly paramagnetic materials suspended in a paramagnetic solution in a magnetic field gradient provides a simple method to measure the density of small samples of solids or liquids. One major limitation of this method, thus far, has been an inability to measure or manipulate materials outside of a narrow range of densities (0.8 g/cm(3) levitated magnetically. Tilting the MagLev device relative to the gravitational vector enables the magnetic force to be decreased (relative to the magnetic force) along the axis of measurement. This approach enables many practical measurements over the entire range of densities observed in matter at ambient conditions-from air bubbles (ρ ≈ 0) to osmium and iridium (ρ ≈ 23 g/cm(3)). The ability to levitate, simultaneously, objects with a broad range of different densities provides an operationally simple method that may find application to forensic science (e.g., for identifying the composition of miscellaneous objects or powders), industrial manufacturing (e.g., for quality control of parts), or resource-limited settings (e.g., for identifying and separating small particles of metals and alloys).

  11. Simultaneous structural and magnetic transitions in YFe 4Ge 2 studied by neutron diffraction and magnetic measurements

    Science.gov (United States)

    Schobinger-Papamantellos, P.; Rodríguez-Carvajal, J.; André, G.; Duong, N. P.; Buschow, K. H. J.; Tolédano, P.

    2001-10-01

    The magnetic behaviour of the tetragonal YFe 4Ge 2 compound has been studied by neutron diffraction and bulk magnetisation measurements. Magnetic ordering occurs below T N=43.5 K simultaneously with a structural transition from tetragonal P4 2/mnm→Pnnm to orthorhombic symmetry. Both transitions are of first order. The symmetry breaking is connected with primary displacive order parameters involving shifts of the Fe atoms. The Fe site splits into two sites in Pnnm, the shifts of the Fe atoms with respect to the tetragonal phase have opposite signs along the a (dilatation) and b (contraction) axes. This induces the symmetry breaking tensile strains. The planar canted antiferromagnetic arrangement with eight sublattices is the ground state associated with a magnetic energy involving isotropic exchange and anisotropic (relativistic) interactions. The magnetic structure is invariant under the magnetic space group P{2 1}/{n' } {2 1}/{n' } {2 1}/{m' } ( Sh58399) . The moments of the two orbits have the same value. At 1.5 K the Fe moment equals 0.63(4) μB/Fe atom. The YFe 4Ge 2 magnetostructural phenomena are compared to the more complex analogue of the ErFe 4Ge 2 compound. The structural and magnetic transitions are described phenomenologically within a Landau-Dzialoshinski approach which assumes a triggering mechanism, in which the spontaneous strain is triggered by the exchange contribution to the magnetic ordering.

  12. Carboxylated magnetic nanoparticles as MRI contrast agents: Relaxation measurements at different field strengths

    Energy Technology Data Exchange (ETDEWEB)

    Jedlovszky-Hajdu, Angela, E-mail: angela.hajdu@net.sote.hu [Laboratory of Nanochemistry, Department of Biophysics and Radiation Biology, Semmelweis University, Nagyvarad Sq 4, H-1089 Budapest (Hungary); Tombacz, Etelka, E-mail: tombacz@chem.u-szeged.hu [Department of Physical Chemistry and Material Science, University of Szeged, Aradi Vt. Sq 1, Szeged 6720 (Hungary); Banyai, Istvan, E-mail: banyai.istvan@science.unideb.hu [Department of Colloid and Environmental Chemistry, University of Debrecen (Hungary); Babos, Magor, E-mail: babosmagor@yahoo.com [Euromedic Diagnostics Szeged Ltd., Semmelweis St 6, Szeged 6720 (Hungary); Palko, Andras, E-mail: palko@radio.szote.u-szeged.hu [Faculty of Medicine, Department of Radiology, University of Szeged (Hungary)

    2012-09-15

    At the moment the biomedical applications of magnetic fluids are the subject of intensive scientific interest. In the present work, magnetite nanoparticles (MNPs) were synthesized and stabilized in aqueous medium with different carboxylic compounds (citric acid (CA), polyacrylic acid (PAA), and sodium oleate (NaOA)), in order to prepare well stabilized magnetic fluids (MFs). The magnetic nanoparticles can be used in the magnetic resonance imaging (MRI) as contrast agents. Magnetic resonance relaxation measurements of the above MFs were performed at different field strengths (i.e., 0.47, 1.5 and 9.4 T) to reveal the field strength dependence of their magnetic responses, and to compare them with that of ferucarbotran, a well-known superparamagnetic contrast agent. The measurements showed characteristic differences between the tested magnetic fluids stabilized by carboxylic compounds and ferucarbotran. It is worthy of note that our magnetic fluids have the highest r2 relaxivities at the field strength of 1.5 T, where the most of the MRI works in worldwide. - Highlights: Black-Right-Pointing-Pointer Magnetic resonance relaxation measurements were done at different field strengths. Black-Right-Pointing-Pointer Results show characteristic differences between the tested carboxylated MFs. Black-Right-Pointing-Pointer r1 and r2 relaxivities depend on the thickness of the protecting layer. Black-Right-Pointing-Pointer MFs have high r2/r1 ratios at each magnetic field.

  13. Trapped field measurements of Gd-Ba-Cu-O bulk superconductor in controlled pulse field magnetizing

    Energy Technology Data Exchange (ETDEWEB)

    Ida, T [Department of Electronic Control Engineering, Hiroshima National College of Maritime Technology, 4272-1, Higashino, Ohsakikamijima-cho, Toyota-gun, Hiroshima 725-0231 (Japan); Kimura, Y; Sano, T; Yamaguchi, K; Izumi, M [Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan); Miki, M [Kitano Seiki Co. Ltd., 7-13-7, Chuo, Ohta-ku, Tokyo 143-0024 (Japan)], E-mail: ida@hiroshima-cmt.ac.jp

    2008-02-01

    For large-scale electric power application of the melt-processed high temperature superconductor (HTS) bulks, especially at rotating machine, development of trapping much higher magnetic fields by using pulsed magnetization technique is essential. It is difficult to use static field cooling (FCM) technique that is most effective magnetizing method for the general industrial HTS applications, because the FCM requires large-scale superconducting magnets. Because the rise in temperature due to the magnetic flux motion decreases the pinning force, we controlled the magnetic flux penetrating to the bulk for the effective magnetization. A couple of vortex-type copper coils applied a magnetic field to a Gd-Ba-Cu-O bulk, which dimension was 45mm in diameter and 19 mm in thickness. HTS bulk was magnetized by the controlled pulse field without passive LCR pulse. We controlled waveform by using the discharge current that IGBT chopper in pulse magnetizer intermitted. We applied the pulse magnetic field with the various risetime to the HTS bulk in liquid nitrogen. The various conditions of the controlled waveform pulse to trap well-dressed profile magnetized the Gd-Ba-Cu-O bulk, strongly at 77K. In the present study, we show several properties which was measured in the PFM of the HTS bulk.

  14. Magnetic particle translation as a surrogate measure for synovial fluid mechanics.

    Science.gov (United States)

    Shah, Yash Y; Maldonado-Camargo, Lorena; Patel, Neal S; Biedrzycki, Adam H; Yarmola, Elena G; Dobson, Jon; Rinaldi, Carlos; Allen, Kyle D

    2017-07-26

    The mechanics of synovial fluid vary with disease progression, but are difficult to quantify quickly in a clinical setting due to small sample volumes. In this study, a novel technique to measure synovial fluid mechanics using magnetic nanoparticles is introduced. Briefly, microspheres embedded with superparamagnetic iron oxide nanoparticles, termed magnetic particles, are distributed through a 100μL synovial fluid sample. Then, a permanent magnet inside a protective sheath is inserted into the synovial fluid sample. Magnetic particles translate toward the permanent magnet and the percentage of magnetic particles collected by the magnet in a given time can be related to synovial fluid viscosity. To validate this relationship, magnetic particle translation was demonstrated in three phases. First, magnetic particle translation was assessed in glycerol solutions with known viscosities, demonstrating that as fluid viscosity increased, magnetic particle translation decreased. Next, the relationship between magnetic particle translation and synovial fluid viscosity was assessed using bovine synovial fluid that was progressively degenerated via ultrasonication. Here, particle collection in a given amount of time increased as fluid degenerated, demonstrating that the relationship between particle collection and fluid mechanics holds in non-Newtonian synovial fluid. Finally, magnetic particle translation was used to assess differences between healthy and OA affected joints in equine synovial fluid. Here, particle collection in a given time was higher in OA joints relative to healthy horses (pmagnetic particle translation in a clinical setting to evaluate synovial fluid mechanics in limited volumes of synovial fluid sample. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Laboratory Testing of Magnetic Tracers for Soil Erosion Measurement*1

    Institute of Scientific and Technical Information of China (English)

    HU Guo-Qing; DONG Yuan-Jie; WANG Hui; QIU Xian-Kui; WANG Yan-Hua

    2011-01-01

    Soil erosion, which includes soil detachment, transport, and deposition, is one of the important dynamic land surface processes. The magnetic tracer method is a useful method for studying soil erosion processes. In this study, five types of magnetic tracers were made with fine soil, fly ash, cement, bentonite, and magnetic powder (reduced iron powder) using the method of disk granulation. The tracers were uniformly mixed with soil and tested in the laboratory using simulated rainfall and inflow experiments to simulate the interrill and rill components of soil erosion, in order to select one or more tracers which could be used to study detachment and deposition by the erosive forces of raindrops and surface flow of water on a slope. The results showed that the five types of magnetic tracers with high magnetic susceptibility and a wide range of sizes had a range of 0.99-1.29 gcm-s in bulk density. In the interrill and rill experiments, the tracers FC1 and FC2 which consisted of fly ash and cement at ratios of 1:1 and 2:1, respectively, were transported in phase with soil particles since the magnetic susceptibility of sediment approximated that of the soil which was uneroded and the slopes of the regression equations between the detachment of sediment and magnetic tracers FC1 and FC2 were very close to the expected value of 20, which was the original soil/tracer ratio. The detachment and deposition on slopes could be accurately reflected by the magnetic susceptibility differences. The change in magnetic susceptibility depended on whether deposition or detachment occurred. However, the tracer FS which consisted of fine soil and the tracers FB1 and FB2 which consisted of fly ash and bentonite at ratios of 1:1 and 2:1, respectively, were all unsuitable for soil erosion study since there was no consistent relationship between sediment and tracer detachment for increasing amounts of runoff. Therefore, the tracers FC1 and FC2 could be used to study soil erosion by water.

  16. Magnetic field measurements of a clinical MR imager at 1.5 tesla

    Science.gov (United States)

    Muhech, A.; Tellez, I.; Esteva, M.; Marrufo, O.; Jimenez, L.; Vazquez, F.; Taboada, J.; Rodriguez, A. O.

    2012-10-01

    In the clinical environment is mandatory to run periodically measurements of uniformity of the magnetic field produced by the magnet to assure good image quality. The phase difference method was used to measure the magnetic field uniformity of the 1.5 T scanner of the Instituto Nacional de Neurologia y Neurocirugia MVS. The uniformity field values showed that the imager performance is reasonably good for clinical imaging. Some concern was raised since results may not be good enough for magnetic resonance spectroscopy runs.

  17. Separation of the Microscopic and Macroscopic Domains

    Science.gov (United States)

    Van Zandt, L. L.

    1977-01-01

    Examines the possibility of observing interference in quantum magnification experiments such as the celebrated "Schroedinger cat". Uses the possibility of observing interference for separating the realm of microscopic from macroscopic dynamics; estimates the dividing line to fall at system sizes of about 100 Daltons. (MLH)

  18. Entropy, Macroscopic Information, and Phase Transitions

    OpenAIRE

    Parrondo, Juan M. R.

    1999-01-01

    The relationship between entropy and information is reviewed, taking into account that information is stored in macroscopic degrees of freedom, such as the order parameter in a system exhibiting spontaneous symmetry breaking. It is shown that most problems of the relationship between entropy and information, embodied in a variety of Maxwell demons, are also present in any symmetry breaking transition.

  19. Macroscopic Modeling of Polymer-Electrolyte Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Weber, A.Z.; Newman, J.

    2007-04-01

    In this chapter, the various approaches for the macroscopic modeling of transport phenomena in polymer-electrolyte membranes are discussed. This includes general background and modeling methodologies, as well as exploration of the governing equations and some membrane-related topic of interest.

  20. Macroscopic invisibility cloaking of visible light

    DEFF Research Database (Denmark)

    Chen, Xianzhong; Luo, Y.; Zhang, Jingjing

    2011-01-01

    to a few wavelengths. Here, we report the first realization of a macroscopic volumetric invisibility cloak constructed from natural birefringent crystals. The cloak operates at visible frequencies and is capable of hiding, for a specific light polarization, three-dimensional objects of the scale...

  1. Macroscopic Quantum Phenomena from the Correlation, Coupling and Criticality Perspectives

    Science.gov (United States)

    Chou, C. H.; Hu, B. L.; Subaşi, Y.

    2011-12-01

    In this sequel paper we explore how macroscopic quantum phenomena can be measured or understood from the behavior of quantum correlations which exist in a quantum system of many particles or components and how the interaction strengths change with energy or scale, under ordinary situations and when the system is near its critical point. We use the nPI (master) effective action related to the Boltzmann-BBGKY / Schwinger-Dyson hierarchy of equations as a tool for systemizing the contributions of higher order correlation functions to the dynamics of lower order correlation functions. Together with the large N expansion discussed in our first paper [1] we explore 1) the conditions whereby an H-theorem is obtained, which can be viewed as a signifier of the emergence of macroscopic behavior in the system. We give two more examples from past work: 2) the nonequilibrium dynamics of N atoms in an optical lattice under the large Script N (field components), 2PI and second order perturbative expansions, illustrating how N and Script N enter in these three aspects of quantum correlations, coherence and coupling strength. 3) the behavior of an interacting quantum system near its critical point, the effects of quantum and thermal fluctuations and the conditions under which the system manifests infrared dimensional reduction. We also discuss how the effective field theory concept bears on macroscopic quantum phenomena: the running of the coupling parameters with energy or scale imparts a dynamical-dependent and an interaction-sensitive definition of 'macroscopia'.

  2. Measurement of Short Living Baryon Magnetic Moment using Bent Crystals at SPS and LHC

    CERN Document Server

    Burmistrov, L; Ivanov, Yu; Massacrier, L; Robbe, P; Scandale, W; Stocchi, A

    2016-01-01

    The magnetic moments of baryons containing u,d and s quarks have been extensively studied and measured. The experimental results are all obtained by a well-assessed method that consists in measuring the polarisation vector of the incoming particles and the precession angle when the particle is travelling through an intense magnetic field. The polarization is evaluated by analysing the angular distribution of the decay products. No measurement of magnetic moments of charm or beauty baryons (and τ leptons) has been performed so far. The main reason is the lifetimes of charm/beauty baryons, too short to measure the magnetic moment by standard techniques. Historically, the prediction of baryon magnetic moments was one of the striking successes of the quark model. The importance of the measurement of heavy quark magnetic moment is to test the possibility that the charmed and/or beauty quarks has an anomalous magnetic moment, arising if those quarks are composite objects. Measurements on magnetic moments of heav...

  3. On-field validation of the new platform for magnetic measurements at CERN

    CERN Document Server

    Arpaia, P; Inglese, V; Spiezia, G

    2009-01-01

    A new platform for magnetic measurements at the European Organization for Nuclear Research (CERN) is presented. The key concepts and the architecture of its main components, a multi-purpose digitizer (fast digital integrator – FDI) and a flexible software framework (flexible framework for magnetic measurements – FFMM), are detailed. The experimental results of the metrological characterization of FDI exhibit a significant advance with respect to the state of the art. Furthermore, the FFMM implementation is shown to provide a reusable and scalable measurement software. Finally, the results of the on-field validation of the platform for field measurements on superconducting magnets in the CERN test facility are discussed.

  4. Optical measurement of anisotropic magnetic susceptibility for diamagnetic fine particles

    Science.gov (United States)

    Kitamura, Naoyuki; Takahashi, Kohki; Mogi, Iwao; Awaji, Satoshi; Watanabe, Kazuo

    2016-01-01

    We have developed an apparatus that allows the observation of the transient rotational motion of fine particles under a high magnetic field in order to determine anisotropic magnetic susceptibility. The anisotropic susceptibilities of spherical nanoparticles of bismuth and commercially available carbon nanofibers were determined. The estimated Δχ = 3.9 × 10-5 of spherical bismuth nanoparticles with a diameter of 370 nm was fairly consistent with the value determined previously by the magnetic field dependence of diffraction peak intensity in the X-ray diffraction (XRD) pattern, but was slightly smaller than the value for the bulk crystal. In contrast, the transient behavior of carbon nanofibers did not obey the theoretical motion of a single crystal. The wide distribution of fiber lengths, the irregularity of the structure in the fiber, and the connections between the fibers are suggested for the anomalous behavior.

  5. LPFG based fiber optic sensor for magnetic field measurement

    Science.gov (United States)

    Gouveia, Carlos A. J.; Coelho, Luís.; Franco, Marcos A. R.

    2017-04-01

    The design and modelling of a novel magnetic field sensor based on a long period fiber grating coated with a thin film of N doped ZnO is reported. The parameters of both, the grating and the thin film were carefully chosen to operate in the transition mode and near to the dispersion turning point. At this point, an LPFG shows its maximum sensitivity to external refractive index variations. The magnetic field induces variations in the coating refractive index, which changes the effective refractive index of the cladding mode and the consequent spectral response. In this work a sensitivity to the surrounding magnetic field of 2.9 nm/mT is reported with a maximum theoretical resolution of 2 μT.

  6. A Mole for Warm Magnetic and Optical Measurements of LHC Dipoles

    CERN Document Server

    Bottura, L; Deferne, G; Glöckner, C; Jansen, H; Köster, A; Legrand, P; Rijllart, A; Sievers, P

    2000-01-01

    A new rotating coil probe (a mole) has been developed for the simultaneous measurement of the magnetic field and magnetic axis of warm superconducting LHC dipoles and associated corrector windings. The mole houses a radial rotating coil and travels inside the magnet aperture by means of an externally driven two-way traction belt. The coil is rotated by an on-board piezo motor, being tested in view of future devices for cold measurements as the only type of motor compatible with strong magnetic fields. A virtual light spot is generated in the coil center by a LED source. The position of this light spot is measured from the outside by a system including a telescope, a CCD camera and a DSP. Jigs on reference granite tables are used to transfer the optical measurements to the magnet fiducials. We describe here the main characteristics and performance of the mole

  7. Nonlinear force-free modelling: influence of inaccuracies in the measured magnetic vector

    CERN Document Server

    Wiegelmann, T; Solanki, S K; Lagg, A

    2009-01-01

    Context: Solar magnetic fields are regularly extrapolated into the corona starting from photospheric magnetic measurements that can suffer from significant uncertainties. Aims: Here we study how inaccuracies introduced into the maps of the photospheric magnetic vector from the inversion of ideal and noisy Stokes parameters influence the extrapolation of nonlinear force-free magnetic fields. Methods: We compute nonlinear force-free magnetic fields based on simulated vector magnetograms, which have been produced by the inversion of Stokes profiles, computed froma 3-D radiation MHD simulation snapshot. These extrapolations are compared with extrapolations starting directly from the field in the MHD simulations, which is our reference. We investigate how line formation and instrumental effects such as noise, limited spatial resolution and the effect of employing a filter instrument influence the resulting magnetic field structure. The comparison is done qualitatively by visual inspection of the magnetic field dis...

  8. Planetary science. Low-altitude magnetic field measurements by MESSENGER reveal Mercury's ancient crustal field.

    Science.gov (United States)

    Johnson, Catherine L; Phillips, Roger J; Purucker, Michael E; Anderson, Brian J; Byrne, Paul K; Denevi, Brett W; Feinberg, Joshua M; Hauck, Steven A; Head, James W; Korth, Haje; James, Peter B; Mazarico, Erwan; Neumann, Gregory A; Philpott, Lydia C; Siegler, Matthew A; Tsyganenko, Nikolai A; Solomon, Sean C

    2015-05-22

    Magnetized rocks can record the history of the magnetic field of a planet, a key constraint for understanding its evolution. From orbital vector magnetic field measurements of Mercury taken by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft at altitudes below 150 kilometers, we have detected remanent magnetization in Mercury's crust. We infer a lower bound on the average age of magnetization of 3.7 to 3.9 billion years. Our findings indicate that a global magnetic field driven by dynamo processes in the fluid outer core operated early in Mercury's history. Ancient field strengths that range from those similar to Mercury's present dipole field to Earth-like values are consistent with the magnetic field observations and with the low iron content of Mercury's crust inferred from MESSENGER elemental composition data. Copyright © 2015, American Association for the Advancement of Science.

  9. Measurement and Modeling of Magnetic Hysteresis in the LHC Superconducting Correctors

    CERN Document Server

    Venturini-Delsolaro, W; Chaudhari, Y; Karppinen, M; Sammut, N

    2006-01-01

    The Large Hadron Collider, now under construction at CERN, relies heavily on superconducting magnets for its optics layout: besides the main magnets, almost all the correcting magnets are superconducting. Along with clear advantages, this brings about complications due to the effects of persistent currents in the superconducting filaments. Corrector magnets that trim key beam parameters or compensate field errors of the main magnets (among others those due to hysteresis), are in their turn hysteretic. In this paper we present the measured magnetic hysteresis and its possible influence on accelerator operation, with particular reference to realtime compensation of dynamic effects in the main magnets, and reproducibility issues between runs. The modeling strategy as a function of the required accuracy is discussed, and two examples are presented.

  10. X-Ray Magnetic Circular Dichroism Measurement of Fe-Co Alloy Films Prepared by Electrodeposition

    Institute of Scientific and Technical Information of China (English)

    LI Zong-Mu; XU Fa-Qiang; WANG Li-Wu; WANG Jie; ZHU Jun-Fa; ZHANG Wen-Hua

    2007-01-01

    The macro- and micro-magnetic properties of Fe-Co alloy films eletrodeposited on GaAs(100) are studied by synchrotron radiation x-ray magnetic circular dichroism (XMCD) in combination with the magneto-optical Kerr effect (MOKE) measurements and magnetic force microscopy (MFM). The orbital and spin magnetic moments of each element in the Fe-Co alloy are determined by the sum rules of XMCD. Element-specific hysteresis loops (ESHL) are obtained by recording the La MCD signals as a function of applied magnetic field. MOKE results reveal that the amorphous films are magnetically isotropic in the surface plane. The MFM image shows that the dimension of the magnetic domains is about 1-2 μm, which is much larger than that of the grains, indicating that there are intergranular correlations among these grains. Both ESHL and MOKE hysteresis loops indicate the strong ferromagnetic coupling of Fe and Co in the alloy films.

  11. Magnetization Measurements of Hard Superconductors under Dissipative Transport

    Energy Technology Data Exchange (ETDEWEB)

    Giordano, J L [Departamento de Ciencias de la IngenierIa, Universidad de Talca (Chile); Luzuriaga, J [Centro Atomico Bariloche, CNEA, Instituto Balseiro, UNC (Argentina); RuIz-Tagle, I A [Instituto de QuImica de Recursos Naturales, Universidad de Talca (Chile); Nieva, G [Centro Atomico Bariloche, CNEA, Instituto Balseiro, UNC (Argentina); BadIa-Majos, A [Departamento de Fisica de la Materia Condensada-I.C.M.A., Universidad de Zaragoza (Spain)

    2006-06-01

    The hysteretic magnetic flux dynamics of ceramic type-II superconductors under superimposed transport current cycles has been investigated. Field cooled and zero field cooled experiments were carried-out on polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-x} cylinders by using both temperature and applied field control, to drive the sample into the semi-reversible granular regime. The transport current magnitude was near and above the dissipative threshold. The interplay between shielding and transport due to vortex-pinning interactions, equilibrium magnetization effects, and diamagnetic/paramagnetic relaxation phenomena are shown to play an important role in the range of practical applications.

  12. Understanding the Pulsar High Energy Emission: Macroscopic and Kinetic Models

    Science.gov (United States)

    Kalapotharakos, Constantinos; Brambilla, Gabriele; Timokhin, Andrey; Kust Harding, Alice; Kazanas, Demos

    2017-08-01

    Pulsars are extraordinary objects powered by the rotation of magnetic fields of order 10^8, 10^12G anchored onto neutron stars and rotating with periods 10^(-3)-10s. These fields mediate the conversion of their rotational energy into MHD winds and at the same time accelerate particles to energies sufficiently high to produce GeV photons. Fermi, since its launch in 2008, has established several trends among the observed gamma-ray pulsar properties playing a catalytic role in the current modeling of the high energy emission in pulsar magnetospheres. We judiciously use the guidance provided by the Fermi data to yield meaningful constraints on the macroscopic parameters of our global dissipative pulsar magnetosphere models. Our FIDO (Force-Free Inside, Dissipative Outside) models indicate that the dissipative regions lie outside the light cylinder near the equatorial current sheet. Our models reproduce the light-curve phenomenology while a detailed comparison of the model spectral properties with those observed by Fermi reveals the dependence of the macroscopic conductivity parameter on the spin-down rate providing a unique insight into the understanding of the physical mechanisms behind the high-energy emission in pulsar magnetospheres. Finally, we further exploit these important results by building self-consistent 3D global kinetic particle-in-cell (PIC) models which, eventually, provide the dependence of the macroscopic parameter behavior (e.g. conductivity) on the microphysical properties (e.g. particle multiplicities, particle injection rates). Our PIC models provide field structures and particle distributions that are not only consistent with each other but also able to reproduce a broad range of the observed gamma-ray phenomenology (light curves and spectral properties) of both young and millisecond pulsars.

  13. Use of environmental magnetic measurements to characterize and correlate tephra -- A case study in Iceland

    Institute of Scientific and Technical Information of China (English)

    XIA Dunsheng; J. Bloemendal; R. C. Chiverrell; J. A. Dearing; JIN Ming

    2004-01-01

    A set of environmental magnetic parameters (i.e. magnetic susceptibility, χARM, IRMs, hysteresis loops and thermomagnetic curves) has been applied to two soil sections from SE Iceland. Results demonstrate that the main magnetic minerals in the tephras are ferrimagnetic minerals (e.g. magnetite) and canted antiferromagnetic minerals (e.g. haematite), with abundant paramagnetic material also present. Cross plots of Mrs/Ms vs. (B0)cr/(B0)c and χfd% vs. χARM/SIRM indicate that the main magnetic grain sizes in tephras are pseudo single domain (PSD) and multidomain (MD). Initial correlation of tephra layers was achieved, using all the measured magnetic parameters, by use of the multivariate statistical measures of Similarity Coefficient (SC) and Euclidean Distance (ED). This demonstrates that magnetic techniques can potentially assist in the identification and correlation of distal tephra.

  14. Measuring the interaction force between a high temperature superconductor and a permanent magnet

    Science.gov (United States)

    Valenzuela, S. O.; Jorge, G. A.; Rodríguez, E.

    1999-11-01

    Repulsive and attractive forces are both possible between a superconducting sample and a permanent magnet, and they can give rise to magnetic levitation or free-suspension phenomena, respectively. We show experiments to quantify this magnetic interaction, which represents a promising field with regard to short-term technological applications of high temperature superconductors. The measuring technique employs an electronic balance and a rare-earth magnet that induces a magnetic moment in a melt-textured YBa2Cu3O7 superconductor immersed in liquid nitrogen. The simple design of the experiments allows a fast and easy implementation in the advanced physics laboratory with a minimum cost. Actual levitation and suspension demonstrations can be done simultaneously as a help to interpret magnetic force measurements.

  15. MAGNETIC MODELING VS MEASUREMENTS OF THE DIPOLES FOR THE JLAB 10 KW FREE ELECTRON LASER UPGRADE

    Energy Technology Data Exchange (ETDEWEB)

    David Douglas; Robin Wines; Tom Hiatt; George Biallas; Kenneth Baggett; T.J. Schultheiss; V.A. Christina; J.W. Rathke; A. Smirnov; D. Newsham; Y. Luo; D. Yu

    2003-05-01

    Magnetic measurements of the six families of dipoles for the infrared Free Electron Laser Upgrade at the Thomas Jefferson National Accelerator Facility (Jlab) are compared to the magnetic models on which their design is based. The magnets were designed in parallel by three organizations. They used ANSYS, Radia or Opera 3D as a 3D magnetic modeling program. Comparison of the discrepancies between model and magnet measurement is presented along with analysis of their potential causes. These dipoles operate in two field ranges. The Injector/ Extractor Dipoles operate around 0.05 T and the Arc Dipoles and Optical Chicane Dipoles operate between 0.22 to 0.71 T. All magnets are required to meet core field and field integral flatness to parts in 104 over their good field region.

  16. Measurement and tricubic interpolation of the magnetic field for the OLYMPUS experiment

    CERN Document Server

    Bernauer, J C; Elbakian, G; Gavrilov, G; Goerrissen, N; Hasel, D K; Henderson, B S; Holler, Y; Karyan, G; Ludwig, J; Marukyan, H; Naryshkin, Y; O'Connor, C; Russell, R L; Schmidt, A; Schneekloth, U; Suvorov, K; Veretennikov, D

    2016-01-01

    The OLYMPUS experiment used a 0.3 T toroidal magnetic spectrometer to measure the momenta of outgoing charged particles. In order to accurately determine particle trajectories, knowledge of the magnetic field was needed throughout the spectrometer volume. For that purpose, the magnetic field was measured at over 36,000 positions using a three-dimensional Hall probe actuated by a system of translation tables. We used these field data to fit a numerical magnetic field model, which could be employed to calculate the magnetic field at any point in the spectrometer volume. Calculations with this model were computationally intensive; for analysis applications where speed was crucial, we pre-computed the magnetic field and its derivatives on an evenly spaced grid so that the field could be interpolated between grid points. We developed a spline-based interpolation scheme suitable for SIMD implementations, with a memory layout chosen to minimize space and optimize the cache behavior to quickly calculate field values....

  17. Measurement of Magnetic Moment at the Atomic Scale in a High TC Molecular Based Magnet

    NARCIS (Netherlands)

    Arrio, M.-A.; Sainctavit, Ph.; Cartier dit Moulin, Ch.; Brouder, Ch.; Groot, F.M.F. de; Mallah, T.; Verdaguer, M.

    2001-01-01

    The molecular-based magnet Cs^(I) [Ni^(II) Cr^(III) (CN)6]-2H2O is a ferromagnetic with a Curie temperature TC ) 90 K. Its structure consists of face-centered cubic lattice of Ni^(II) ions connected by Cr(CN)6 entities. We have recorded X-ray magnetic circular dichroism (XMCD) at nickel L2,3 edges.

  18. Violation of smooth observable macroscopic realism in a harmonic oscillator.

    Science.gov (United States)

    Leshem, Amir; Gat, Omri

    2009-08-14

    We study the emergence of macrorealism in a harmonic oscillator subject to consecutive measurements of a squeezed action. We demonstrate a breakdown of dynamical realism in a wide parameter range that is maximized in a scaling limit of extreme squeezing, where it is based on measurements of smooth observables, implying that macroscopic realism is not valid in the harmonic oscillator. We propose an indirect experimental test of these predictions with entangled photons by demonstrating that local realism in a composite system implies dynamical realism in a subsystem.

  19. Non-invasively measured cardiac magnetic field maps improve the estimation of the current distribution

    OpenAIRE

    Kosch, Olaf; Steinhoff, Uwe; Trahms, Lutz; Trontelj, Zvonko; Jazbinšek, Vojko

    2015-01-01

    Comprehensive body surface potential mapping (BSPM) and magnetic field mapping (MFM) measurements have been carried out in order to improve the estimation of the current distribution generated by the human heart. Electric and magnetic fields and also the planar gradient of the magnetic field during the QRS complex were imaged as a time series of field maps. A model of the current distribution should explain the features of both BSPM and MFM. Simulated maps generated by a single dipole or a st...

  20. Determination of error measurement by means of the basic magnetization curve

    Science.gov (United States)

    Lankin, M. V.; Lankin, A. M.

    2016-04-01

    The article describes the implementation of the methodology for determining the error search by means of the basic magnetization curve of electric cutting machines. The basic magnetization curve of the integrated operation of the electric characteristic allows one to define a fault type. In the process of measurement the definition of error calculation of the basic magnetization curve plays a major role as in accuracies of a particular characteristic can have a deleterious effect.

  1. Measurements of weak localization of graphene in inhomogeneous magnetic fields

    DEFF Research Database (Denmark)

    Lindvall, N.; Shivayogimath, Abhay; Yurgens, A.

    2015-01-01

    Weak localization in graphene is studied in inhomogeneous magnetic fields. To generate the inhomogeneous field, a thin film of type-II superconducting niobium is put in close proximity to graphene. A deviation from the ordinary quadratic weak localization behavior is observed at low fields. We...

  2. Measurements of flux pumping activation of trapped field magnets

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Roy; Parks, Drew; Sawh, Ravi-Persad [Texas Center for Superconductivity, 202 Houston Science Center, University of Houston, Houston, TX 77204-5002 (United States); Davey, Kent [Physics Department, 617 Science and Research Building I, University of Houston, Houston, TX 77204-5005 (United States)

    2010-11-15

    Large grains of high temperature superconducting (HTS) material can be utilized as trapped field magnets (TFMs). Persistent currents are set up in the HTS when it is cooled in a magnetic field, or exposed to a magnetic field after cooling. TFMs have been improved over the past two decades by the efforts of a large number of worldwide research groups. However, applications using TFMs have lagged, in part due to the problem of high fields needed for activation. We describe herein experiments designed to observe the behaviour of TFM activation using repeated applications of low fields (called 'pumping'). Significant partial activation is obtained using a non-uniform pumping field (e.g., a small permanent magnet) which is higher in the centre of the HTS than at the periphery. Cooling in zero field followed by pumping with such a field results in trapping the full applied field, in comparison to half of the applied field being trapped by cooling in zero field followed by application of a uniform field. We find that for partial activation by cooling in a field and subsequent activation by pumping, the resulting fields are additive. We also conclude that for activation by fluxoid pumping, creep assists the process.

  3. Conductivity measurements with trapezoidal a.c. magnetic fields

    NARCIS (Netherlands)

    Gijsbertse, E.A.; Klundert, van de L.J.M.

    1981-01-01

    The inductive response of normal metals to trapezoidal a.c. fields is studied theoretically as well as experimentally. A method is presented to determine the conductivity and its magnetic induction dependence from the decay of the induced voltage during periods of constant field. The correctness of

  4. Estimating the contribution of Brownian and Néel relaxation in a magnetic fluid through dynamic magnetic susceptibility measurements

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado-Camargo, L. [Department of Chemical Engineering, University of Florida, Gainesville, FL 32611 (United States); Torres-Díaz, I. [J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611 (United States); Chiu-Lam, A. [Department of Chemical Engineering, University of Florida, Gainesville, FL 32611 (United States); Hernández, M. [J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611 (United States); Rinaldi, C., E-mail: carlos.rinaldi@bme.ufl.edu [Department of Chemical Engineering, University of Florida, Gainesville, FL 32611 (United States); J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2016-08-15

    We demonstrate how dynamic magnetic susceptibility measurements (DMS) can be used to estimate the relative contributions of Brownian and Néel relaxation to the dynamic magnetic response of a magnetic fluid, a suspension of magnetic nanoparticles. The method applies to suspensions with particles that respond through Brownian or Néel relaxation and for which the characteristic Brownian and Néel relaxation times are widely separated. First, we illustrate this using magnetic fluids consisting of mixtures of particles that relax solely by the Brownian or Néel mechanisms. Then, it is shown how the same approach can be applied to estimate the relative contributions of Brownian and Néel relaxation in a suspension consisting of particles obtained from a single synthesis and whose size distribution straddles the transition from Néel to Brownian relaxation. - Highlights: • Method to estimate the contributions of the relaxation mechanism to the magnetic response. • Method applies to cases where the Brownian and Néel peaks do not overlap. • The method applies for ferrofluids prepared with as–synthesized particles.

  5. Multifield measurement of magnetic fluctuation-induced particle flux in a high-temperature toroidal plasma

    Science.gov (United States)

    Lin, L.; Ding, W. X.; Brower, D. L.

    2016-12-01

    Magnetic fluctuation-induced particle transport is explored in the high-temperature, high-beta interior of the Madison symmetric torus (MST) reversed-field pinch by performing a multifield measurement of the correlated product of magnetic and density fluctuations associated with global resistive tearing modes. Local density fluctuations are obtained by inverting the line-integrated interferometry data after resolving the mode helicity through correlation techniques. The local magnetic and current density fluctuations are then reconstructed using a parameterized fit of Faraday-effect polarimetry measurements. Reconstructed 2D images of density and current density perturbations in a poloidal cross section exhibit significantly different spatial structure. Combined with their relative phase, the magnetic-fluctuation-induced particle transport flux and its spatial distribution are resolved. The convective magnetic fluctuation-induced particle flux profile is measured for both standard and high-performance plasmas in MST with tokamak-like confinement, showing large reduction in the flux during improved confinement.

  6. DEVELOPMENT OF EMBEDDED SYSTEM FOR REMOTE MEASURING OF DYNAMIC MAGNETIC FIELDS USING ZIGBEE

    Directory of Open Access Journals (Sweden)

    Thiago Dantas da Silva

    2016-04-01

    Full Text Available This paper aims to describe the development and implementation of an embedded system applied to remote measurement of dynamic artificial magnetic fields using Zigbee, which is a set of specifications for wireless data communication (based on IEEE standard 802.15.4. In the implementation of this system, Arduino microcontrolled platforms were used integrated to a Hall effect sensor intended for measuring the strength of these dynamic magnetic fields. The Zigbee technology aims to enable the execution of real-time and in remote character of these measurements of magnetic field intensity, presenting them in a graphical view.

  7. Spatially resolved measurements of the magnetocaloric effect and the local magnetic field using thermography

    DEFF Research Database (Denmark)

    Christensen, Dennis; Bjørk, Rasmus; Nielsen, Kaspar Kirstein

    2010-01-01

    The magnetocaloric effect causes a magnetic material to change temperature upon application of a magnetic field. Here, spatially resolved measurements of the adiabatic temperature change are performed on a plate of gadolinium using thermography. The adiabatic temperature change is used to extract...

  8. Biosensor based on the measurements of clustering dynamics of magnetic particles using a double pass setup

    DEFF Research Database (Denmark)

    2014-01-01

    Disclosed herein is a biosensor for optical detection of Brownian relaxation dynamics of magnetic particles measured by light transmission. The magnetic particles can be functionalized with biological ligands for the detection of target analytes in a sample. The setup may be implemented in a disc...

  9. Indirect measurement of the magnetocaloric effect using a novel differential scanning calorimeter with magnetic field

    DEFF Research Database (Denmark)

    Jeppesen, Stinus; Linderoth, Søren; Pryds, Nini

    2008-01-01

    been compared to results from a Quantum Design® physical properties measuring system. The configuration of the system also has the advantage of being able to operate with other types of magnets, e.g., permanent magnets or superconducting coils, as well as the ability to be expanded to a wider...

  10. Resolution of direction of oceanic magnetic lineations by the sixth-generation lithospheric magnetic field model from CHAMP satellite magnetic measurements

    Science.gov (United States)

    Maus, S.; Yin, F.; Lühr, H.; Manoj, C.; Rother, M.; Rauberg, J.; Michaelis, I.; Stolle, C.; Müller, R. D.

    2008-07-01

    The CHAMP satellite continues to provide highly accurate magnetic field measurements from decreasing orbital altitudes (<350 km) at solar minimum conditions. Using the latest 4 years (2004-2007) of readings from the CHAMP fluxgate magnetometer, including an improved scalar data product, we have estimated the lithospheric magnetic field to spherical harmonic degree 120, corresponding to 333 km wavelength resolution. The data were found to be sensitive to crustal field variations up to degree 150 (down to 266 km wavelength), but a clean separation of the lithospheric signal from ionospheric and magnetospheric noise sources was achieved only to degree 120. This new MF6 model is the first satellite-based magnetic model to resolve the direction of oceanic magnetic lineations, revealing the age structure of oceanic crust.

  11. Characterization of magnetized ore bodies based on three-component borehole magnetic and directional borehole seismic measurements

    Science.gov (United States)

    Virgil, Christopher; Neuhaus, Martin; Hördt, Andreas; Giese, Rüdiger; Krüger, Kay; Jurczyk, Andreas; Juhlin, Christopher; Juhojuntti, Niklas

    2016-04-01

    In the last decades magnetic prospecting using total field data was used with great success for localization and characterization of ferromagnetic ore bodies. Especially borehole magnetic measurements reveal important constraints on the extent and depth of potential mining targets. However, due to the inherent ambiguity of the interpretation of magnetic data, the resulting models of the distribution of magnetized material, such as iron ore bodies, are not entirely reliable. Variations in derived parameters like volume and estimated ore content of the expected body have significant impact on the economic efficiency of a planned mine. An important improvement is the introduction of three-component borehole magnetic sondes. Modern tools comprise orientation modules which allow the continuous determination of the tool's heading regardless of the well inclination and independent of the magnetic field. Using the heading information the recorded three-component magnetic data can be transferred from the internal tool's frame to the geographic reference frame. The vector information yields a more detailed and reliable description of the ore bodies compared to total field or horizontal and vertical field data. Nevertheless complementary information to constrain the model is still advisable. The most important supplementary information for the interpretation of magnetic data is the knowledge of the structural environment of the target regions. By discriminating dissimilar rock units, a geometrical starting model can be derived, constraining the magnetic interpretation and leading to a more robust estimation of the rock magnetizations distribution. The most common approach to reveal the lithological setting rests upon seismic measurements. However, for deep drilling targets surface seismic and VSP lack the required spatial resolution of 10s of meters. A better resolution is achieved by using directed sources and receivers inside the borehole. Here we present the application of

  12. Magnetoresistance, susceptibility and magnetization measurements on RNiBC compounds (R = Er, Ho, Dy, Tb, and Gd)

    Science.gov (United States)

    Tróchez, J. C.; Sánchez, D. R.; Giordanengo, B.; Fontes, M. B.; Continentino, Múcio; Baggio-Saitovitch, E. M.

    1997-08-01

    We studied magnetic behavior of the RNiBC compounds by magnetic and transport measurements. At low temperatures, each compound has different magnetic structure. Magnetoresistivity data are in good accordance with theory of magnetic elementary interactions, susceptibility reveals the magnetic transition and Curie Weiss behavior and magnetization shows low value of the saturation compared with the free R+3 ion that confirm that crystalline electric field is strong as in the RNi2B2C series.

  13. Advanced measurement systems based on digital processing techniques for superconducting LHC magnets

    CERN Document Server

    Masi, Alessandro; Cennamo, Felice

    The Large Hadron Collider (LHC), a particle accelerator aimed at exploring deeper into matter than ever before, is currently being constructed at CERN. Beam optics of the LHC, requires stringent control of the field quality of about 8400 superconducting magnets, including 1232 main dipoles and 360 main quadrupoles to assure the correct machine operation. The measurement challenges are various: accuracy on the field strength measurement up to 50 ppm, harmonics in the ppm range, measurement equipment robustness, low measurement times to characterize fast field phenomena. New magnetic measurement systems, principally based on analog solutions, have been developed at CERN to achieve these goals. This work proposes the introduction of digital technologies to improve measurement performance of three systems, aimed at different measurement target and characterized by different accuracy levels. The high accuracy measurement systems, based on rotating coils, exhibit high performance in static magnetic field. With vary...

  14. Experimental Measurement of Asymmetric Fluctuations of Poloidal Magnetic Field in Damavand Tokomak at Different Plasma Currents

    Science.gov (United States)

    Moslehi-Fard, Mahmoud; Alinejad, Naser; Rasouli, Chapar; Sadigzadeh, Asghar

    2012-08-01

    Toroidal and Poloidal magnetic fields have an important effect on the tokomak topology. Damavand Tokomak is a small size tokomak characterized with k = 1.2, B t = 1T, R 0 = 36 cm, maximum plasma current is about 35 KA with a discharge time of 21 ms. In this experimental work, the variation of poloidal magnetic field on the torodial cross section is measured and analyzed. In order to measure the polodial magnetic field, 18 probes were installed on the edge of tokomak plasma with ∆θ = 18°, while a limiter was installed inside the torus. Plasma current, I p, induces a polodial magnetic field, B p, smaller than the torodial magnetic field B t. Magnetic lines B produced as a combination of B t and B p, are localized on the nested toroidal magnetic surfaces. The presence of polodial magnetic field is necessary for particles confinement. Mirnov oscillations are the fluctuations of polodial magnetic field, detected by magnetic probes. Disrupted instability in Tokomak typically starts with mirnov oscillations which appear as fluctuations of polodial magnetic field and is detected by magnetic probes. Minor disruptions inside the plasma can contain principal magnetic islands and their satellites can cause the annihilation of plasma confinement. Production of thin layer of turbulent magnetic field lines cause minor disruption. Magnetic limiter may cause the deformation of symmetric equilibrium configuration and chaotic magnetic islands reveal in plasma occurring in thin region of chaotic field lines close to their separatrix. The width of this chaotic layer in the right side of poloidal profile of Damavand Tokomak is smaller than the width in the left side profile because of Shafranov displacement. Ergodic region in the left side of profile develops a perturbation on the magnetic polodial field lines, B p, that are greater in magnitude than that in the right side, although the values of B p on the left side are smaller than that on the right side of the profile. The Left

  15. First Measurement of the Magnetic Turbulence Induced Reynolds Stress in a Tokamak

    Institute of Scientific and Technical Information of China (English)

    徐国盛; 万宝年; 宋梅

    2003-01-01

    Reynolds stress component due to magnetic turbulence was first measured in the plasma edge region of the HT- 7 superconducting tokamak using an insertable magnetic probe. A radial gradient of magnetic Reynolds stress was observed to be dose to the velocity shear layer location; however, in this experiment its contribution to driving the poloidal flows is small compared to the electrostatic component. The electron heat transport driven by magnetic turbulence is quite small and cannot account for the total energy transport at the plasma edge.

  16. About the parametrizations utilized to perform magnetic moments measurements using the transient field technique

    Science.gov (United States)

    Gómez, A. M.; Torres, D. A.

    2016-07-01

    The experimental study of nuclear magnetic moments, using the Transient Field technique, makes use of spin-orbit hyperfine interactions to generate strong magnetic fields, above the kilo-Tesla regime, capable to create a precession of the nuclear spin. A theoretical description of such magnetic fields is still under theoretical research, and the use of parametrizations is still a common way to address the lack of theoretical information. In this contribution, a review of the main parametrizations utilized in the measurements of Nuclear Magnetic Moments will be presented, the challenges to create a theoretical description from first principles will be discussed.

  17. Measurement of hot electron transport in overdense plasma VIA self induced giant magnetic pulses

    Science.gov (United States)

    Mondal, S.; Narayanan, V.; Lad, Amit D.; Ahmed, Saima; Sengupta, S.; Das, A.; Sheng, Z. M.; Kaw, P. K.; Kumar, G. Ravindra

    2010-08-01

    Spatial and temporal resolved ultrashort(8ps) multimegagauss(65 MG) magnetic field has been measured in plasma produced on Al-coated BK-7 glass by the interaction of a relativististic intensity laser(4x1018W/cm2, 30 fs) using pump-probe polarimetry. The 2D profile of magnetic field is captured using a CCD camera. Mapping of this magnetic field maps the transport of relativistic electrons in the plasma. The magnetic field profiles indicate filamentary behavior (Weibel-like instability). Particle in cell simulation are used to explain the result obtained.

  18. Direct Measurements of Magnetic Twist in the Solar Corona

    CERN Document Server

    Malanushenko, A; Longcope, D W

    2012-01-01

    In the present work we study evolution of magnetic helicity in the solar corona. We compare the rate of change of a quantity related to the magnetic helicity in the corona to the flux of magnetic helicity through the photosphere and find that the two rates are similar. This gives observational evidence that helicity flux across the photosphere is indeed what drives helicity changes in solar corona during emergence. For the purposes of estimating coronal helicity we neither assume a strictly linear force-free field, nor attempt to construct a non-linear force-free field. For each coronal loop evident in Extreme Ultraviolet (EUV) we find a best-matching line of a linear force-free field and allow the twist parameter alpha to be different for each line. This method was introduced and its applicability was discussed in Malanushenko et. al. (2009). The object of the study is emerging and rapidly rotating AR 9004 over about 80 hours. As a proxy for coronal helicity we use the quantity averaged over many reconstruc...

  19. Macroscopic quantum mechanics in a classical spacetime.

    Science.gov (United States)

    Yang, Huan; Miao, Haixing; Lee, Da-Shin; Helou, Bassam; Chen, Yanbei

    2013-04-26

    We apply the many-particle Schrödinger-Newton equation, which describes the coevolution of a many-particle quantum wave function and a classical space-time geometry, to macroscopic mechanical objects. By averaging over motions of the objects' internal degrees of freedom, we obtain an effective Schrödinger-Newton equation for their centers of mass, which can be monitored and manipulated at quantum levels by state-of-the-art optomechanics experiments. For a single macroscopic object moving quantum mechanically within a harmonic potential well, its quantum uncertainty is found to evolve at a frequency different from its classical eigenfrequency-with a difference that depends on the internal structure of the object-and can be observable using current technology. For several objects, the Schrödinger-Newton equation predicts semiclassical motions just like Newtonian physics, yet quantum uncertainty cannot be transferred from one object to another.

  20. Macroscopic Invisibility Cloaking of Visible Light

    CERN Document Server

    Chen, Xianzhong; Zhang, Jingjing; Jiang, Kyle; Pendry, John B; Zhang, Shuang

    2010-01-01

    Invisibility cloaks of light, which used to be confined to the imagination, have now been turned into a scientific reality, thanks to the enabling theoretical tools of transformation optics and conformal mapping. Inspired by those theoretical works, the experimental realisation of electromagnetic invisibility cloaks has been reported at various electromagnetic frequencies. All the invisibility cloaks demonstrated thus far, however, have relied on nano- or micro-fabricated artificial composite materials with spatially varying electromagnetic properties, which limit the size of the cloaked region to a few wavelengths. Here we report realisation of a macroscopic volumetric invisibility cloak constructed from natural birefringent crystals. The cloak operates at visible frequencies and is capable of hiding three-dimensional objects of the scale of centimetres and millimetres. Our work opens avenues for future applications with macroscopic cloaking devices.

  1. Macroscopic entrainment of periodically forced oscillatory ensembles.

    Science.gov (United States)

    Popovych, Oleksandr V; Tass, Peter A

    2011-03-01

    Large-amplitude oscillations of macroscopic neuronal signals, such as local field potentials and electroencephalography or magnetoencephalography signals, are commonly considered as being generated by a population of mutually synchronized neurons. In a computational study in generic networks of phase oscillators and bursting neurons, however, we show that this common belief may be wrong if the neuronal population receives an external rhythmic input. The latter may stem from another neuronal population or an external, e.g., sensory or electrical, source. In that case the population field potential may be entrained by the rhythmic input, whereas the individual neurons are phase desynchronized both mutually and with their field potential. Intriguingly, the corresponding large-amplitude oscillations of the population mean field are generated by pairwise desynchronized neurons oscillating at frequencies shifted far away from the frequency of the macroscopic field potential.

  2. Macroscopic Invisible Cloak for Visible Light

    CERN Document Server

    Zhang, Baile; Liu, Xiaogang; Barbastathis, George

    2011-01-01

    Invisibility cloaks, a subject that usually occurs in science fiction and myths, have attracted wide interest recently because of their possible realization. The biggest challenge to true invisibility is known to be the cloaking of a macroscopic object in the broad range of wavelengths visible to the human eye. Here we experimentally solve this problem by incorporating the principle of transformation optics into a conventional optical lens fabrication with low-cost materials and simple manufacturing techniques. A transparent cloak made of two pieces of calcite is created. This cloak is able to conceal a macroscopic object with a maximum height of 2 mm, larger than 3500 free-space-wavelength, inside a transparent liquid environment. Its working bandwidth encompassing red, green and blue light is also demonstrated.

  3. INVESTIGATION OF POTENTIALITIES TO SET AUTOMATICALLY AMPLITUDE VALUES OF MAGNETIC INDUCTION WHILE MEASURING MAGNETIC CHARACTERISTICS OF ELECTRICAL-SHEET STEEL

    Directory of Open Access Journals (Sweden)

    I. I. Branovitsky

    2005-01-01

    Full Text Available The problems relating to an automation of measurement of magnetic characteristics of electrical-sheet steel have been considered in the paper. The paper investigates efficiency of an application of some well-known iterative methods for setting the required amplitude value of a magnetic induction of the material to be tested. It is shown that the most efficient method providing a fast and stable convergence of an iterative process while testing either textured or isotropic electrical-sheet steel is a parabola method.

  4. Macroscopic Quantum Resonators (MAQRO): 2015 update

    Energy Technology Data Exchange (ETDEWEB)

    Kaltenbaek, Rainer [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Aspelmeyer, Markus; Kiesel, Nikolai [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Barker, Peter F.; Bose, Sougato [University College London, Department of Physics and Astronomy, London (United Kingdom); Bassi, Angelo [University of Trieste, Department of Physics, Trieste (Italy); INFN - Trieste Section, Trieste (Italy); Bateman, James [University of Swansea, Department of Physics, College of Science, Swansea (United Kingdom); Bongs, Kai; Cruise, Adrian Michael [University of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Braxmaier, Claus [University of Bremen, Center of Applied Space Technology and Micro Gravity (ZARM), Bremen (Germany); Institute of Space Systems, German Aerospace Center (DLR), Bremen (Germany); Brukner, Caslav [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Austrian Academy of Sciences, Institute of Quantum Optics and Quantum Information (IQOQI), Vienna (Austria); Christophe, Bruno; Rodrigues, Manuel [The French Aerospace Lab, ONERA, Chatillon (France); Chwalla, Michael; Johann, Ulrich [Airbus Defence and Space GmbH, Immenstaad (Germany); Cohadon, Pierre-Francois; Heidmann, Antoine; Lambrecht, Astrid; Reynaud, Serge [ENS-PSL Research University, Laboratoire Kastler Brossel, UPMC-Sorbonne Universites, CNRS, College de France, Paris (France); Curceanu, Catalina [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Dholakia, Kishan; Mazilu, Michael [University of St. Andrews, School of Physics and Astronomy, St. Andrews (United Kingdom); Diosi, Lajos [Wigner Research Center for Physics, P.O. Box 49, Budapest (Hungary); Doeringshoff, Klaus; Peters, Achim [Humboldt-Universitaet zu Berlin, Institut fuer Physik, Berlin (Germany); Ertmer, Wolfgang; Rasel, Ernst M. [Leibniz Universitaet Hannover, Institut fuer Quantenoptik, Hannover (Germany); Gieseler, Jan; Novotny, Lukas; Rondin, Loic [ETH Zuerich, Photonics Laboratory, Zuerich (Switzerland); Guerlebeck, Norman; Herrmann, Sven; Laemmerzahl, Claus [University of Bremen, Center of Applied Space Technology and Micro Gravity (ZARM), Bremen (Germany); Hechenblaikner, Gerald [Airbus Defence and Space GmbH, Immenstaad (Germany); European Southern Observatory (ESO), Garching bei Muenchen (Germany); Hossenfelder, Sabine [KTH Royal Institute of Technology and Stockholm University, Nordita, Stockholm (Sweden); Kim, Myungshik [Imperial College London, QOLS, Blackett Laboratory, London (United Kingdom); Milburn, Gerard J. [University of Queensland, ARC Centre for Engineered Quantum Systems, Brisbane (Australia); Mueller, Holger [University of California, Department of Physics, Berkeley, CA (United States); Paternostro, Mauro [Queen' s University, Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Belfast (United Kingdom); Pikovski, Igor [Harvard-Smithsonian Center for Astrophysics, ITAMP, Cambridge, MA (United States); Pilan Zanoni, Andre [Airbus Defence and Space GmbH, Immenstaad (Germany); CERN - European Organization for Nuclear Research, EN-STI-TCD, Geneva (Switzerland); Riedel, Charles Jess [Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada); Roura, Albert [Universitaet Ulm, Institut fuer Quantenphysik, Ulm (Germany); Schleich, Wolfgang P. [Universitaet Ulm, Institut fuer Quantenphysik, Ulm (Germany); Texas A and M University Institute for Advanced Study (TIAS), Institute for Quantum Science and Engineering (IQSE), and Department of Physics and Astronomy, College Station, TX (United States); Schmiedmayer, Joerg [Vienna University of Technology, Vienna Center for Quantum Science and Technology, Institute of Atomic and Subatomic Physics, Vienna (Austria); Schuldt, Thilo [Institute of Space Systems, German Aerospace Center (DLR), Bremen (Germany); Schwab, Keith C. [California Institute of Technology, Applied Physics, Pasadena, CA (United States)

    2016-12-15

    Do the laws of quantum physics still hold for macroscopic objects - this is at the heart of Schroedinger's cat paradox - or do gravitation or yet unknown effects set a limit for massive particles? What is the fundamental relation between quantum physics and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times and the quality of vacuum and microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) may overcome these limitations and allow addressing such fundamental questions. MAQRO harnesses recent developments in quantum optomechanics, high-mass matter-wave interferometry as well as state-of-the-art space technology to push macroscopic quantum experiments towards their ultimate performance limits and to open new horizons for applying quantum technology in space. The main scientific goal is to probe the vastly unexplored 'quantum-classical' transition for increasingly massive objects, testing the predictions of quantum theory for objects in a size and mass regime unachievable in ground-based experiments. The hardware will largely be based on available space technology. Here, we present the MAQRO proposal submitted in response to the 4th Cosmic Vision call for a medium-sized mission (M4) in 2014 of the European Space Agency (ESA) with a possible launch in 2025, and we review the progress with respect to the original MAQRO proposal for the 3rd Cosmic Vision call for a medium-sized mission (M3) in 2010. In particular, the updated proposal overcomes several critical issues of the original proposal by relying on established experimental techniques from high-mass matter-wave interferometry and by introducing novel ideas for particle loading and manipulation. Moreover, the mission design was improved to better fulfill the stringent environmental requirements for macroscopic quantum experiments. (orig.)

  5. A macroscopic approach to creating exotic matter

    OpenAIRE

    Ridgely, C. T.

    2000-01-01

    Herein the Casimir effect is used to present a simple macroscopic view on creating exotic matter. The energy arising between two nearly perfectly conducting parallel plates is shown to become increasingly negative as the plate separation is reduced. It is proposed that the Casimir energy appears increasingly negative simply because the vacuum electromagnetic zero-point field performs positive work in pushing the plates together, transforming field energy into kinetic energy of the plates. Nex...

  6. Shot noise in linear macroscopic resistors

    OpenAIRE

    Gomila Lluch, Gabriel; Pennetta, C.; Reggiani, L.; Ferrari, G; Sampietro, M.; G. Bertuccio(Politecnico di Milano, Italy)

    2004-01-01

    We report on direct experimental evidence of shot noise in a linear macroscopic resistor. The origin of the shot noise comes from the fluctuation of the total number of charge carriers inside the resistor associated with their diffusive motion under the condition that the dielectric relaxation time becomes longer than the dynamic transit time. The present results show that neither potential barriers nor the absence of inelastic scattering are necessary to observe shot noise in electronic devi...

  7. Shot Noise in Linear Macroscopic Resistors

    Science.gov (United States)

    Gomila, G.; Pennetta, C.; Reggiani, L.; Sampietro, M.; Ferrari, G.; Bertuccio, G.

    2004-06-01

    We report on direct experimental evidence of shot noise in a linear macroscopic resistor. The origin of the shot noise comes from the fluctuation of the total number of charge carriers inside the resistor associated with their diffusive motion under the condition that the dielectric relaxation time becomes longer than the dynamic transit time. The present results show that neither potential barriers nor the absence of inelastic scattering are necessary to observe shot noise in electronic devices.

  8. Macroscopic Objects, Intrinsic Spin, and Lorentz Violation

    CERN Document Server

    Atkinson, David W; Tasson, Jay D

    2013-01-01

    The framework of the Standard-Model Extension (SME) provides a relativistic quantum field theory for the study of Lorentz violation. The classical, nonrelativistic equations of motion can be extracted as a limit that is useful in various scenarios. In this work, we consider the effects of certain SME coefficients for Lorentz violation on the motion of macroscopic objects having net intrinsic spin in the classical, nonrelativistic limit.

  9. Spectroscopic measurements of railgun plasma armatures in an augmented railgun using a permanent magnet

    Energy Technology Data Exchange (ETDEWEB)

    Katsuki, S.; Sueda, T.; Koga, Y.; Akiyama, H. [Kumamoto Univ. (Japan). Dept. of Electrical Engineering and Computer Science; Sato, K.N. [National Inst. for Fusion Science, Nagoya (Japan)

    1997-01-01

    Small bore railguns have been developed to demonstrate the acceleration of frozen hydrogen pellets which are used to refuel magnetically confined fusion reactors. Here, measurements of electron density using Stark broadening of the H{sub a} line are performed to investigate the behavior of plasma armatures in railguns with and without an augmenting magnetic field. A permanent magnet with a magnetic flux density of 1.25 T was used to augment the magnetic field of one railgun. Driving currents of 20 and 25 kA are supplied to the railguns with and without the augmenting magnetic field, respectively, in order to maintain the same peak Lorentz force on the projectile. Also a gradual temporal increase in electron density and length of the plasma armature is observed in the augmented railgun.

  10. Measuring the Magnetic Flux Density with Flux Loops and Hall Probes in the CMS Magnet Flux Return Yoke

    CERN Document Server

    Curé, B; Ball, A; Gaddi, A; Gerwig, H; Hervé, A; Klyukhin, V I; Loveless, R; Mulders, M

    2016-01-01

    The Compact Muon Solenoid (CMS) is a general purpose detector, designed to run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its distinctive features include a 4 T superconducting solenoid with 6-m-diameter by 12.5-m-length free bore, enclosed inside a 10,000-ton return yoke made of construction steel. The flux return yoke consists of five dodecagonal three-layered barrel wheels and four end-cap disks at each end comprised of steel blocks up to 620 mm thick, which serve as the absorber plates of the muon detection system. To measure the field in and around the steel, a system of 22 flux loops and 82 3-D Hall sensors is installed on the return yoke blocks. A TOSCA 3-D model of the CMS magnet is developed to describe the magnetic field everywhere outside the tracking volume that was measured with the field-mapping machine. The voltages induced in the flux loops by the magnetic flux changing during the CMS magnet standard ramps down are measured with six 16-bit DAQ modules. The off-line inte...

  11. Active Polar Two-Fluid Macroscopic Dynamics

    Science.gov (United States)

    Pleiner, Harald; Svensek, Daniel; Brand, Helmut R.

    2014-03-01

    We study the dynamics of systems with a polar dynamic preferred direction. Examples include the pattern-forming growth of bacteria (in a solvent, shoals of fish (moving in water currents), flocks of birds and migrating insects (flying in windy air). Because the preferred direction only exists dynamically, but not statically, the macroscopic variable of choice is the macroscopic velocity associated with the motion of the active units. We derive the macroscopic equations for such a system and discuss novel static, reversible and irreversible cross-couplings connected to this second velocity. We find a normal mode structure quite different compared to the static descriptions, as well as linear couplings between (active) flow and e.g. densities and concentrations due to the genuine two-fluid transport derivatives. On the other hand, we get, quite similar to the static case, a direct linear relation between the stress tensor and the structure tensor. This prominent ``active'' term is responsible for many active effects, meaning that our approach can describe those effects as well. In addition, we also deal with explicitly chiral systems, which are important for many active systems. In particular, we find an active flow-induced heat current specific for the dynamic chiral polar order.

  12. Estudo macroscópico e dinamométrico comparativo de implantes (ímãs recobertos e de suas técnicas de fixação em órbitas de coelhas Comparative macroscopic and dynamometric study of implants (covered magnets and techniques of their fixation in orbits of female rabbits

    Directory of Open Access Journals (Sweden)

    Elcio Roque Kleinpaul

    2004-06-01

    Full Text Available OBJETIVOS: Avaliação clínica dos sinais da reação inflamatória de fixação de implante orbitário (ímã recoberto por ouro e avaliação macroscópica de sua resistência aos fluidos orgânicos. MÉTODOS: Estudo experimental em 54 coelhas adultas, divididas em três grupos de 18, com 3 subgrupos de 6 de acordo com o material usado para fixação, avaliação com uma, três e seis semanas de pós-operatório. Fixação, no rebordo inferior da órbita, de implante (ímã e ouro por meio de cola ou parafuso ou fio inabsorvível (Mersilene 5.0®. As órbitas contralaterais (sem implante compuseram o grupo-controle. Medidas da resistência à tração tangencial do implante fixado. RESULTADOS: Sinais clínicos de reação inflamatória à fixação orbitária do implante foram observados com cianoacrilato, parafuso, ou sutura inabsorvível (Mersilene 5.0®, até a sexta semana de pós-operatório, sendo mais intensa no grupo F (fixação com fio. A força de tração de 80 gf, independentemente do tipo de fixação, não produziu arrancamentos em 94,5% dos implantes na primeira semana, 100% na terceira semana e em 94,5% dos casos na sexta semana. CONCLUSÃO: Sinais clínicos de reação inflamatória do implante e sua fixação foram observados com cianoacrilato ou parafuso ou sutura inabsorvível (Mersilene 5.0® até a sexta semana pós-operatória, sendo mais intensa no grupo F (fio. A resistência do implante aos fluídos orgânicos mostrou falha em 9,3% (implante com dano.PURPOSE: To evaluate the clinical signs of inflammatory reaction in the fixation of an orbitary implant (magnet, covered by gold, and to evaluate the macroscopic resistance to organic fluids of the used implants. METHODS: An experimental study was performed in 54 adult female rabbits, divided into 3 groups of eighteen with 3 subgroups of 6 according to the material used for fixation; the implants were evaluated at weeks 1, 3 and 6 after surgery. An implant (magnet

  13. The application of magnetic measurements for the characterization of atmospheric particulate pollution within the airport environment.

    Science.gov (United States)

    Jones, S; Richardson, N; Bennett, M; Hoon, S R

    2015-01-01

    The significant increase in global air travel which has occurred during the last fifty years has generated growing concern regarding the potential impacts associated with increasing emissions of atmospheric particulate matter (PM) on health and the environment. PM within the airport environment may be derived from a range of sources. To date, however, the identification of individual sources of airport derived PM has remained elusive but constitutes a research priority for the aviation industry.The aim of this research was to identify distinctive and characteristic fingerprints of atmospheric PM derived from various sources in an airport environment through the use of environmental magnetic measurements. PM samples from aircraft engine emissions, brake wear and tire wear residues have been obtained from a range of different aircraft and engine types. Samples have been analyzed utilizing a range of magnetic mineral properties indicative of magnetic mineralogy and grain size. Results indicate that the dusts from the three 'aircraft' sources, (i.e. engines, brakes and tires) display distinctive magnetic mineral characteristics which may serve as 'magnetic fingerprints' for these sources. Magnetic measurements of runway dusts collected at different locations on the runway surface also show contrasting magnetic characteristics which, when compared with those of the aircraft-derived samples, suggest that they may relate to different sources characteristic of aircraft emissions at various stages of the take-off/landing cycle. The findings suggest that magnetic measurements could have wider applicability for the differentiation and identification of PM within the airport environment.

  14. Noninvasive myocardial strain measurement by speckle tracking echocardiography: validation against sonomicrometry and tagged magnetic resonance imaging

    National Research Council Canada - National Science Library

    Amundsen, Brage H; Helle-Valle, Thomas; Edvardsen, Thor; Torp, Hans; Crosby, Jonas; Lyseggen, Erik; Støylen, Asbjørn; Ihlen, Halfdan; Lima, João A C; Smiseth, Otto A; Slørdahl, Stig A

    2006-01-01

    The aim of this study was to validate speckle tracking echocardiography (STE) as a method for angle-independent measurement of regional myocardial strain, using sonomicrometry and magnetic resonance imaging (MRI...

  15. Auroral Electrojet Index Designed to Provide a Global Measure, Hourly Intervals, of Auroral Zone Magnetic Activity

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Auroral Electrojet (AE) index is designed to provide a global quantitative measure of auroral zone magnetic activity produced by enhanced ionospheric currents...

  16. On-chip Brownian relaxation measurements of magnetic nanobeads in the time domain

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Rizzi, Giovanni; Hansen, Mikkel Fougt

    2013-01-01

    magnetic fields are needed. First, the method is demonstrated on Brownian relaxation measurements of beads with nominal sizes of 40, 80, 130, and 250 nm. The results are found to compare well to those obtained by an already established measurement technique in the frequency domain. Next, we demonstrate......We present and demonstrate a new method for on-chip Brownian relaxation measurements on magnetic nanobeads in the time domain using magnetoresistive sensors. The beads are being magnetized by the sensor self-field arising from the bias current passed through the sensors and thus no external...... the time and frequency domain methods on Brownian relaxation detection of clustering of streptavidin coated magnetic beads in the presence of different concentrations of biotin-conjugated bovine serum albumin and obtain comparable results. In the time domain, a measurement is carried out in less than 30 s...

  17. The Two-Time Interpretation and Macroscopic Time-Reversibility

    Directory of Open Access Journals (Sweden)

    Yakir Aharonov

    2017-03-01

    Full Text Available The two-state vector formalism motivates a time-symmetric interpretation of quantum mechanics that entails a resolution of the measurement problem. We revisit a post-selection-assisted collapse model previously suggested by us, claiming that unlike the thermodynamic arrow of time, it can lead to reversible dynamics at the macroscopic level. In addition, the proposed scheme enables us to characterize the classical-quantum boundary. We discuss the limitations of this approach and its broad implications for other areas of physics.

  18. Macroscopic and microscopic self-organization by nonlocal anisotropic interactions

    CERN Document Server

    Cristiani, Emiliano; Tosin, Andrea

    2009-01-01

    This paper is concerned with mathematical modeling of intelligent systems, such as human crowds and animal groups. In particular, the focus is on the emergence of different self-organized patterns from non-locality and anisotropy of the interactions among individuals. A mathematical technique by time-evolving measures is introduced to deal with both macroscopic and microscopic scales within a unified modeling framework. Then self-organization issues are investigated and numerically reproduced at the proper scale, according to the kind of agents under consideration.

  19. Measurement of Microbially Induced Transformation of Magnetic Iron Minerals in Soils Allows Localization of Hydrocarbon Contamination

    Science.gov (United States)

    Kappler, A.; Porsch, K.; Rijal, M.; Appel, E.

    2007-12-01

    Soil contamination by crude oil and other hydrocarbons represents a severe environmental problem, but often the location and extent of contamination is not known. Hydrocarbons, or their degradation products, can stimulate iron-metabolizing microorganisms, leading to the formation or dissolution of (magnetic) iron minerals and an associated change of soil magnetic properties. Therefore, the screening of soil magnetic properties has the potential to serve as an efficient and inexpensive tool to localize such contaminations. In order to identify the influence of different biogeochemical factors on the microbially influenced changes of magnetic iron minerals after hydrocarbon contamination, oil spills were simulated in laboratory batch experiments. The parameters tested in these experiments included soils with different bedrocks, type and amount of added hydrocarbon, and microbiological parameters (sterile and autochthonous microorganisms). In order to follow the changes of the soil magnetic properties, the magnetic susceptibility of the samples was measured weekly. First results show that changes in the magnetic mineralogy are caused by microbial activity, as sterile samples showed no changes. In the microbially active set-ups, the magnetic susceptibility increased or decreased up to 10% in comparison to the initial magnetic susceptibility within a few weeks. In one iron-rich soil even a decrease of the magnetic susceptibility of ~40% was observed. Although the amount and type of hydrocarbons did not effect the changes in magnetic susceptibility, DGGE fingerprints revealed that they influenced microbial communities. These results show that the magnetic susceptibility changes in the presence of hydrocarbons and that this change is microbially induced. This suggests that the screening of soil magnetic properties can be applied to localize and assess hydrocarbon contamination. In order to understand the biogeochemical processes better, the change of the iron mineralogy

  20. Automatic Test Bench for the Measurement of the Magnetic Interference on LVDTs

    CERN Document Server

    Spiezia, G; Masi, A; Pierno, A; Martino, M

    2010-01-01

    This paper proposes a rigorous and repeatable measurement procedure to analyze the effects of magnetic interferences on Linear Variable Differential Transformer sensors. This issue is neither addressed in the sensor datasheet, nor in the scientific literature. The potential of the method and the performance of an automated test bench, that implements the procedure, are proved by measuring the drift of the position reading due to external magnetic interferences on a commercial LVDT. Finally, the repeatability of the test bench is shown.

  1. DEVELOPMENT OF EMBEDDED SYSTEM FOR REMOTE MEASURING OF DYNAMIC MAGNETIC FIELDS USING ZIGBEE

    OpenAIRE

    Thiago Dantas da Silva; Jacques Cousteau da Silva Borges; Allan Aminadab André Freire Soares

    2016-01-01

    This paper aims to describe the development and implementation of an embedded system applied to remote measurement of dynamic artificial magnetic fields using Zigbee, which is a set of specifications for wireless data communication (based on IEEE standard 802.15.4). In the implementation of this system, Arduino microcontrolled platforms were used integrated to a Hall effect sensor intended for measuring the strength of these dynamic magnetic fields. The Zigbee technology aims to enable the ex...

  2. Array of 12 coils to measure the position, alignment, and sensitivity of magnetic sensors over temperature

    Science.gov (United States)

    Husstedt, Hendrik; Ausserlechner, Udo; Kaltenbacher, Manfred

    2012-04-01

    A measurement setup is presented that allows one to determine the position, alignment, and sensitivity of magnetic sensors over temperature. To this end, an array of 12 coils is used where the number of coils is larger than the number of unknowns to increase accuracy, and to ensure an adequate measurement signal for an arbitrary orientation of the magnetic sensors. With this coil array, a 3D sensing system is analyzed which is used during the testing of automotive magnetic sensors. In particular, the influence of assembly tolerances, and the variation of temperature are examined.

  3. Magnetic field gradients inferred from multi-point measurements of Cluster FGM and EDI

    Science.gov (United States)

    Teubenbacher, Robert; Nakamura, Rumi; Giner, Lukas; Plaschke, Ferdinand; Baumjohann, Wolfgang; Magnes, Werner; Eichelberger, Hans; Steller, Manfred; Torbert, Roy

    2013-04-01

    We use Cluster data from fluxgate magnetometer (FGM) and electron drift instrument (EDI) to determine the magnetic field gradients in the near-Earth magnetotail. Here we use the magnetic field data from FGM measurements as well as the gyro-time data of electrons determined from the time of flight measurements of EDI. The results are compared with the values estimated from empirical magnetic field models for different magnetospheric conditions. We also estimated the spin axis offset of FGM based on comparison between EDI and FGM data and discuss the possible effect in determining the current sheet characteristics.

  4. HTS SQUID application for measuring the magnetic properties of AISI type 316L(N) steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, D.G. E-mail: dgpark@nanum.kaeri.re.kr; Kim, D.W.; Hong, J.H.; Timofeev, V.P.; Kim, C.G

    2000-06-02

    A portable RF HTS SQUID-based susceptometer was used for small-size magnetized sample testing in weak DC (up to 200 A/m) and AC (up to 4 A/m) magnetic fields. The system resolution for the magnetic moment is of the order of 1.6x10{sup -10} A m{sup 2}. The measured DC susceptibility of a tested sample of Gd{sub 88}La{sub 12} agrees well with the value obtained by using a commercial liquid helium susceptometer. The measured volume susceptibility of AISI type 316L(N) steel increases after fatigue due to the microcrack induced by cyclic stress.

  5. Measurement Method of Magnetic Field for the Wire Suspended Micro-Pendulum Accelerometer

    Directory of Open Access Journals (Sweden)

    Yongle Lu

    2015-04-01

    Full Text Available Force producer is one of the core components of a Wire Suspended Micro-Pendulum Accelerometer; and the stability of permanent magnet in the force producer determines the consistency of the acceleration sensor’s scale factor. For an assembled accelerometer; direct measurement of magnetic field strength is not a feasible option; as the magnetometer probe cannot be laid inside the micro-space of the sensor. This paper proposed an indirect measurement method of the remnant magnetization of Micro-Pendulum Accelerometer. The measurement is based on the working principle of the accelerometer; using the current output at several different scenarios to resolve the remnant magnetization of the permanent magnet. Iterative Least Squares algorithm was used for the adjustment of the data due to nonlinearity of this problem. The calculated remnant magnetization was 1.035 T. Compared to the true value; the error was less than 0.001 T. The proposed method provides an effective theoretical guidance for measuring the magnetic field of the Wire Suspended Micro-Pendulum Accelerometer; correcting the scale factor and temperature influence coefficients; etc.

  6. Optical transmission versus ac magnetization measurements for monitoring colloidal Ni nanorod rotational dynamics

    Science.gov (United States)

    Gratz, M.; Tschöpe, A.

    2017-01-01

    Ni nanorods with an average length transmission of nanorod colloidal dispersions in alternating magnetic fields were measured and analyzed with the objective of comparing the intrinsic Brownian relaxation times obtained with the two methods. The different physical origin of the measured signal, related to different moments of the orientation distribution function, and the non-linear effects expected for the large magnetic moments of the Ni nanorods at common field amplitudes required a comprehensive modelling. The time-dependent magnetization and optical transmission in ac magnetic fields was derived by numerical solution of the Fokker-Planck equation. The simulated time-dependent magnetization and optical transmission at a given frequency and field amplitude were analyzed analogous to experimental data to determine characteristic relaxation frequencies. Empirical relationships were derived which enabled extraction of the intrinsic Brownian relaxation time from the characteristic frequencies measured in the non-linear regime. Despite large differences in the characteristic frequencies obtained from magnetization and optical transmission measurements, the retrieved intrinsic Brownian relaxation times were found to agree well. The potential of ac magnetic field-dependent optical transmission for biosensing applications was demonstrated by monitoring the adsorption of the protein gelatine on the nanorod labels.

  7. MAGNET

    CERN Multimedia

    B. Curé

    MAGNET During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bough...

  8. Generation and measurement of multi megagauss fields in inertial magnets

    Indian Academy of Sciences (India)

    N Nalini; T C Kaushik; S C Gupta

    2010-10-01

    We present here the development of a facility to generate high (multi megagauss) magnetic field of 4 to 5 s rise time, using inertial magnets. The facility includes a low inductance, high current capacitor bank (280 kJ/40 kV) and an inertial magnet, which is a copper disk machined to have a keyhole in it. As the high current from the capacitor bank is discharged through the copper disk, a high magnetic field is produced along its axis, before it is destroyed by the combined effect of the dynamic loading and skin effect. A maximum peak magnetic field of 257 T is realized, when the magnet with 3·6 mm inner diameter, 35 mm outer diameter and 5 mm length, is powered by the capacitor bank charged to 28 kV (134 kJ). The transient magnetic field is measured using a B dot probe with an error of ±25 T. The probe in most of high field shots (> 200 T) got destroyed before recording the peak field and the trailing edge of the magnetic field. Experimental evidence of enhancement of the probe survival for longer time in copper disks using spatial non-uniform conductivity with 1 mm thick SS brazed to the inner wall of the inertial magnet is also reported.

  9. Comparison among T1-Weighted Magnetic Resonance Imaging, Modified Dixon Method, and Magnetic Resonance Spectroscopy in Measuring Bone Marrow Fat

    Directory of Open Access Journals (Sweden)

    Wei Shen

    2013-01-01

    Full Text Available Introduction. An increasing number of studies are utilizing different magnetic resonance (MR methods to quantify bone marrow fat due to its potential role in osteoporosis. Our aim is to compare the measurements of bone marrow fat among T1-weighted magnetic resonance imaging (MRI, modified Dixon method (also called fat fraction MRI (FFMRI, and magnetic resonance spectroscopy (MRS. Methods. Contiguous MRI scans were acquired in 27 Caucasian postmenopausal women with a modified Dixon method (i.e., FFMRI. Bone marrow adipose tissue (BMAT of T1-weighted MRI and bone marrow fat fraction of the L3 vertebra and femoral necks were quantified using SliceOmatic and Matlab. MRS was also acquired at the L3 vertebra. Results. Correlation among the three MR methods measured bone marrow fat fraction and BMAT ranges from 0.78 to 0.88 in the L3 vertebra. Correlation between BMAT measured by T1-weighted MRI and bone marrow fat fraction measured by modified FFMRI is 0.86 in femoral necks. Conclusion. There are good correlations among T1-weighted MRI, FFMRI, and MRS for bone marrow fat quantification. The inhomogeneous distribution of bone marrow fat, the threshold segmentation of the T1-weighted MRI, and the ambiguity of the FFMRI may partially explain the difference among the three methods.

  10. Using magnetization measurements to detect small amounts of plutonium hydride formation in plutonium metal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Wook [Rutgers Univ., New Brunswick, NJ (United States); Mielke, Charles H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zapf, Vivien [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baiardo, Joseph P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mitchell, Jeremy N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Richmond, Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schwartz, Daniel S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mun, Eun D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Alice Iulia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-10-20

    We report the formation of plutonium hydride in 2 at % Ga-stabilized δ-Pu, with 1 atomic % H charging. We show that magnetization measurements are a sensitive, quantitative measure of ferromagnetic plutonium hydride against the nonmagnetic background of plutonium. It was previously shown that at low hydrogen concentrations, hydrogen forms super-abundant vacancy complexes with plutonium, resulting in a bulk lattice contraction. Here we use magnetization, X-ray and neutron diffraction measurements to show that in addition to forming vacancy complexes, at least 30% of the H atoms bond with Pu to precipitate PuHx, largely on the surface of the sample with x ~ 1.9. We observe magnetic hysteresis loops below 40 K with magnetic remanence, consistent with precipitates of ferromagnetic PuH1.9.

  11. Large Magnetic Shielding Factor Measured by Nonlinear Magneto-optical Rotation

    CERN Document Server

    Martin, Jeffery W; Klassen, Wolfgang; Cerasani, Cameron; Andalib, Taraneh; Bidinosti, Christopher P; Lang, Michael; Ostapchuk, David

    2014-01-01

    A passive magnetic shield was designed and constructed for magnetometer tests for the future neutron electric dipole moment experiment at TRIUMF. The axial shielding factor of the magnetic shield was measured using a magnetometer based on non-linear magneto-optical rotation of the plane of polarized laser light upon passage through a paraffin-coated vapour cell containing natural Rb at room temperature. The laser was tuned to the Rb D1 line, near the $^{85}$Rb $F=2\\rightarrow 2,3$ transition. The shielding factor was measured by applying an axial field externally and measuring the magnetic field internally using the magnetometer. The axial shielding factor was determined to be $(1.3\\pm 0.1)\\times 10^{7}$, from an applied axial field of 1.45~$\\mu$T in the background of Earth's magnetic field.

  12. Design and test of the benches for the magnetic measurement of the LHC dipoles

    Science.gov (United States)

    Billan, J.; Buckley, J.; Saban, R.; Sievers, P.; Walckiers, L.

    1994-07-01

    The magnetic measurement of more than 1300 LHC dipoles comprises the content of higher harmonic field components, field direction and field integrals. The measurements will be carried out along a warm bore installed inside the magnet cold bore, thus allowing the use of rotating coils at room temperature. This coil, together with Hall and NMR detectors is mounted at one end of a 12.5 m long shaft which is specially designed for very high rotational stiffness and which is controlled from its far end by a motor, an angular encoder and a level meter, all standard components placed outside the magnetic field without space restrictions. Particular emphasis has been put on the user-friendliness of the bench and its automated, computer-controlled operation requiring a minimum of staff, an important issue during production measurements of large series of magnets. The bench and its performance and precision achieved during its commissioning are described.

  13. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, A; Silevitch, D M; Feng, Yejun; Wang, Y; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure–field–temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  14. Underground localization using dual magnetic field sequence measurement and pose graph SLAM for directional drilling

    Science.gov (United States)

    Park, Byeolteo; Myung, Hyun

    2014-12-01

    With the development of unconventional gas, the technology of directional drilling has become more advanced. Underground localization is the key technique of directional drilling for real-time path following and system control. However, there are problems such as vibration, disconnection with external infrastructure, and magnetic field distortion. Conventional methods cannot solve these problems in real time or in various environments. In this paper, a novel underground localization algorithm using a re-measurement of the sequence of the magnetic field and pose graph SLAM (simultaneous localization and mapping) is introduced. The proposed algorithm exploits the property of the drilling system that the body passes through the previous pass. By comparing the recorded measurement from one magnetic sensor and the current re-measurement from another magnetic sensor, the proposed algorithm predicts the pose of the drilling system. The performance of the algorithm is validated through simulations and experiments.

  15. Measurements of Brownian relaxation of magnetic nanobeads using planar Hall effect bridge sensors.

    Science.gov (United States)

    Østerberg, F W; Rizzi, G; Zardán Gómez de la Torre, T; Strömberg, M; Strømme, M; Svedlindh, P; Hansen, M F

    2013-02-15

    We compare measurements of the Brownian relaxation response of magnetic nanobeads in suspension using planar Hall effect sensors of cross geometry and a newly proposed bridge geometry. We find that the bridge sensor yields six times as large signals as the cross sensor, which results in a more accurate determination of the hydrodynamic size of the magnetic nanobeads. Finally, the bridge sensor has successfully been used to measure the change in dynamic magnetic response when rolling circle amplified DNA molecules are bound to the magnetic nanobeads. The change is validated by measurements performed in a commercial AC susceptometer. The presented bridge sensor is, thus, a promising component in future lab-on-a-chip biosensors for detection of clinically relevant analytes, including bacterial genomic DNA and proteins.

  16. Evaluation of right ventricular volumes measured by magnetic resonance imaging

    DEFF Research Database (Denmark)

    Møgelvang, J; Stubgaard, M; Thomsen, C

    1988-01-01

    Right ventricular volumes were determined in 12 patients with different levels of right and left ventricular function by magnetic resonance imaging (MRI) using an ECG gated multisection technique in planes perpendicular to the diastolic position of the interventricular septum. Right ventricular...... stroke volume was calculated as the difference between end-diastolic and end-systolic volume and compared to left ventricular stroke volume and to stroke volume determined simultaneously by a classical indicator dilution technique. There was good agreement between right ventricular stroke volume...... determined by MRI and by the indicator dilution method and between right and left ventricular stroke volume determined by MRI. Thus, MRI gives reliable values not only for left ventricular volumes, but also for right ventricular volumes. By MRI it is possible to obtain volumes from both ventricles...

  17. A flux extraction device to measure the magnetic moment of large samples; application to bulk superconductors.

    Science.gov (United States)

    Egan, R; Philippe, M; Wera, L; Fagnard, J F; Vanderheyden, B; Dennis, A; Shi, Y; Cardwell, D A; Vanderbemden, P

    2015-02-01

    We report the design and construction of a flux extraction device to measure the DC magnetic moment of large samples (i.e., several cm(3)) at cryogenic temperature. The signal is constructed by integrating the electromotive force generated by two coils wound in series-opposition that move around the sample. We show that an octupole expansion of the magnetic vector potential can be used conveniently to treat near-field effects for this geometrical configuration. The resulting expansion is tested for the case of a large, permanently magnetized, type-II superconducting sample. The dimensions of the sensing coils are determined in such a way that the measurement is influenced by the dipole magnetic moment of the sample and not by moments of higher order, within user-determined upper bounds. The device, which is able to measure magnetic moments in excess of 1 A m(2) (1000 emu), is validated by (i) a direct calibration experiment using a small coil driven by a known current and (ii) by comparison with the results of numerical calculations obtained previously using a flux measurement technique. The sensitivity of the device is demonstrated by the measurement of flux-creep relaxation of the magnetization in a large bulk superconductor sample at liquid nitrogen temperature (77 K).

  18. Study of Train-Side Passive Magnetic Measurements with Applications to Train Localization

    Directory of Open Access Journals (Sweden)

    Oliver Heirich

    2017-01-01

    Full Text Available Passive magnetic sensors measure the magnetic field density in three axes and are often integrated on a single chip. These low-cost sensors are widely used in car navigation as well as in battery powered navigation equipment such as smartphones as part of an electronic compass. We focus on a train localization application with multiple, exclusively onboard sensors and a track map. This approach is considered as a base technology for future railway applications such as collision avoidance systems or autonomous train driving. In this paper, we address the following question: how beneficial are passive magnetic measurements for train localization? We present and analyze measurements of two different magnetometers recorded on a regional train at regular passenger service. We show promising correlations of the measurements with the track positions and the traveled switch way. The processed data reveals that the railway environment has repeatable, location-dependent magnetic signatures. This is considered as a novel approach to train localization, as the use of these magnetic signals at first view is not obvious. The proposed methods based on passive magnetic measurements show a high potential to be integrated in new and existing train localization approaches.

  19. Ring to measure magnetic permeability at cryogenic temperatures

    CERN Multimedia

    1977-01-01

    While for magn. permeability measurements at room temperature a split-coil permeameter is used (see photo 7708553X), for measurements at cryogenic temperatures the excitation and the flux-measuring coils are wound directly on the ring sample by means of a toroidal winding machine. The ring in the picture was made to select the mild steel for the ISR Prototype Superconducting Quadrupole(see photo 7702690X). The excitation coil was wound with 1 mm diam. copper wire and had about 2730 turns. For measurements at 4.2 K a max. current of 90 A was used. See also photos 7708553X,7708100,7708103.

  20. Simulation and Field Measurement of Quadrupole Magnets for KOMAC 20MeV Beam line

    Energy Technology Data Exchange (ETDEWEB)

    Chung, B. H.; Kim, H. S.; Song, Y. G.; Kwon, H. J.; Cho, Y. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    In this paper, quadrupole magnets the same as installed at the beam line simulated and analyzed for magnetic fields. Also quadrupole magnets will be measured field stability and evaluated reliability on long time operation. Control system consisted of Labview program and communication method consisted of Ethernet and Rs-232 with optical fiber for devices safety from high voltage and/or high current. As a results the DC power supply is controlled, magnetic fields data is acquired and coil temperature is measured. Magnetic field with hall sensor and temperature with K-type thermo-couple are measured with conversion factor using by voltmeter. Korea Multi-purpose Accelerator Complex (KOMAC) was developed at Gyeongju in Korea in 2012. KOMAC including a 50-keV ion source, a 3-MeV RFQ, and a 100-MeV DTL. And beam line consists of 20-MeV and 100-MeV for user. Proton beam transferred from the linac to the beam line using by dipole magnets and transferred proton beam focused and decreased beam loss and by quadrupole magnets.