WorldWideScience

Sample records for measured magnetic hysteresis

  1. Magnetic Hysteresis

    CERN Document Server

    Della Torre, Edward

    2000-01-01

    Understanding magnetic hysteresis is vitally important to the development of the science of magnetism as a whole and to the advancement of practical magnetic device applications. Magnetic Hysteresis, by acclaimed expert Edward Della Torre, presents a clear explanation of the connection between physical principles and phenomenological hysteresis. This comprehensive book offers a lucid analysis that enables the reader to save valuable time by reducing trial-and-error design. Dr. Della Torre uses physical principles to modify Preisach modeling and to describe the complex behavior of magnetic media. While Pretsach modeling is a useful mathematical tool, its congruency and deletion properties present limitations to accurate descriptions of magnetic materials. Step-by-step, this book describes the modifications that can overcome these limitations. Special attention is given to the use of feedback around a Preisach transducer to remove the congruency restriction, and to the use of accommodation and aftereffect model...

  2. Magnetic hysteresis measurements of thin films under isotropic stress.

    Science.gov (United States)

    Holland, Patrick; Dubey, Archana; Geerts, Wilhelmus

    2000-10-01

    Nowadays, ferromagnetic thin films are widely applied in devices for information technology (credit cards, video recorder tapes, floppies, hard disks) and sensors (air bags, anti-breaking systems, navigation systems). Thus, with the increase in the use of magnetic media continued investigation of magnetic properties of materials is necessary to help in determining the useful properties of materials for new or improved applications. We are currently interested in studying the effect of applied external stress on Kerr hysteresis curves of thin magnetic films. The Ni and NiFe films were grown using DC magnetron sputtering with Ar as the sputter gas (pAr=4 mTorr; Tsub=55-190 C). Seed and cap layers of Ti were used on all films for adhesion and oxidation protection, respectively. A brass membrane pressure cell was designed to apply in-plane isotropic stress to thin films. In this pressure cell, gas pressure is used to deform a flexible substrate onto which a thin magnetic film has been sputtered. The curvature of the samples could be controlled by changing the gas pressure to the cell. Magneto-Optical in-plane hysteresis curves at different values of strain were measured. The results obtained show that the stress sensitivity is dependent on the film thickness. For the 500nm NiFe films, the coercivity strongly decreased as a function of the applied stress.

  3. Corrections for hysteresis curves for rare earth magnet materials measured by open magnetic circuit methods

    International Nuclear Information System (INIS)

    Nakagawa, Yasuaki

    1996-01-01

    The methods for testing permanent magnets stipulated in the usual industrial standards are so-called closed magnetic circuit methods which employ a loop tracer using an iron-core electromagnet. If the coercivity exceeds the highest magnetic field generated by the electromagnet, full hysteresis curves cannot be obtained. In the present work, magnetic fields up to 15 T were generated by a high-power water-cooled magnet, and the magnetization was measured by an induction method with an open magnetic circuit, in which the effect of a demagnetizing field should be taken into account. Various rare earth magnets materials such as sintered or bonded Sm-Co and Nd-Fe-B were provided by a number of manufacturers. Hysteresis curves for cylindrical samples with 10 nm in diameter and 2 mm, 3.5 mm, 5 mm, 14 mm or 28 mm in length were measured. Correction for the demagnetizing field is rather difficult because of its non-uniformity. Roughly speaking, a mean demagnetizing factor for soft magnetic materials can be used for the correction, although the application of this factor to hard magnetic material is hardly justified. Thus the dimensions of the sample should be specified when the data obtained by the open magnetic circuit method are used as industrial standards. (author)

  4. 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

    2016-01-01

    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 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. PMID:27426442

  5. Magnetic fluid hyperthermia probed by both calorimetric and dynamic hysteresis measurements

    Energy Technology Data Exchange (ETDEWEB)

    Guibert, Clément; Fresnais, Jérôme; Peyre, Véronique; Dupuis, Vincent, E-mail: vincent.dupuis@upmc.fr

    2017-01-01

    In this paper, we report an investigation of magnetic fluid hyperthermia (MFH) using combined calorimetric and newly implemented dynamic hysteresis measurements for two sets of well characterized size-sorted maghemite nanoparticles (with diameters of about 10 nm and 20 nm) dispersed in water and in glycerol. Our primary goal was to assess the influence of viscosity on the heating efficiency of magnetic nanoparticles described in terms of specific loss power (SLP or specific absorption rate, SAR) and dynamic hysteresis. In particular, we aimed to investigate how this SLP depends on the transition from Néelian to Brownian behavior of nanoparticles expected to occur between 10 nm and 20 nm (for maghemite) and dependent on the viscosity. While we observed a good agreement between calorimetric and dynamic hysteresis measurements, we found that the SLP measured for the different systems do not depend noticeably on the viscosity of solvent. Calculations performed according to Rosensweig's linear model [1] allow us to quantitatively reproduce our results at low field intensities, provided we use a value for the magnetic anisotropy constant much smaller than the one commonly used in the literature. This raises the question of the temperature dependance of the magnetic anisotropy constant and its relevance for a quantitative description of MFH. - Highlights: • Dynamic hysteresis measurements are a promising tool to study magnetic hyperthermia. • Dynamic hysteresis cycles can be reproduced using a simple model. • The effect of viscosity on hyperthermia of maghemite is weaker than expected.

  6. A system for controllable magnetic measurements of hysteresis and Barkhausen noise

    Czech Academy of Sciences Publication Activity Database

    Stupakov, Oleksandr; Perevertov, Oleksiy; Zablotskyy, Vitaliy A.

    2016-01-01

    Roč. 65, č. 5 (2016), s. 1087-1097 ISSN 0018-9456. [IEEE International Instrumentation and Measurement Technology Conference (I2MTC 2015). Pisa, 11.05.2015-14.05.2015] R&D Projects: GA ČR GA13-18993S Institutional support: RVO:68378271 Keywords : Barkhausen effect * feedback circuits * magnetic field measurement * magnetic hysteresis * magnetization processes * silicon steel Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 2.456, year: 2016

  7. Measurement method for determining the magnetic hysteresis effects of reluctance actuators by evaluation of the force and flux variation

    NARCIS (Netherlands)

    Vrijsen, N.H.; Jansen, J.W.; Compter, J.C.; Lomonova, E.

    2013-01-01

    A measurement method is presented which identifies the magnetic hysteresis effects present in the force of linear reluctance actuators. The measurement method is applied to determine the magnetic hysteresis in the force of an E-core reluctance actuator, with and without pre-biasing permanent magnet.

  8. Hysteresis losses and specific absorption rate measurements in magnetic nanoparticles for hyperthermia applications.

    Science.gov (United States)

    Coïsson, Marco; Barrera, Gabriele; Celegato, Federica; Martino, Luca; Kane, Shashank N; Raghuvanshi, Saroj; Vinai, Franco; Tiberto, Paola

    2017-06-01

    Magnetic hysteresis loops areas and hyperthermia on magnetic nanoparticles have been studied with the aim of providing reliable and reproducible methods of measuring the specific absorption rate (SAR). The SAR of Fe 3 O 4 nanoparticles with two different mean sizes, and Ni 1-x Zn x Fe 2 O 4 ferrites with 0 ≤ x ≤ 0.8 has been measured with three approaches: static hysteresis loops areas, dynamic hysteresis loops areas and hyperthermia of a water solution. For dynamic loops and thermometric measurements, specific experimental setups have been developed, that operate at comparable frequencies (≈ 69kHz and ≈ 100kHz respectively) and rf magnetic field peak values (up to 100mT). The hyperthermia setup has been fully modelled to provide a direct measurement of the SAR of the magnetic nanoparticles by taking into account the heat exchange with the surrounding environment in non-adiabatic conditions and the parasitic heating of the water due to ionic currents. Dynamic hysteresis loops are shown to provide an accurate determination of the SAR except for superparamagnetic samples, where the boundary with a blocked regime could be crossed in dynamic conditions. Static hysteresis loops consistently underestimate the specific absorption rate but can be used to select the most promising samples. A means of reliably measure SAR of magnetic nanoparticles by different approaches for hyperthermia applications is presented and its validity discussed by comparing different methods. This work fits within the general subject of metrological traceability in medicine with a specific focus on magnetic hyperthermia. This article is part of a Special Issue entitled "Recent Advances in Bionanomaterials" Guest Editor: Dr. Marie-Louise Saboungi and Dr. Samuel D. Bader. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Measurement and modeling of magnetic hysteresis under field and stress application in iron–gallium alloys

    International Nuclear Information System (INIS)

    Evans, Phillip G.; Dapino, Marcelo J.

    2013-01-01

    Measurements are performed to characterize the hysteresis in magnetomechanical coupling of iron–gallium (Galfenol) alloys. Magnetization and strain of production and research grade Galfenol are measured under applied stress at constant field, applied field at constant stress, and alternately applied field and stress. A high degree of reversibility in the magnetomechanical coupling is demonstrated by comparing a series of applied field at constant stress measurements with a single applied stress at constant field measurement. Accommodation is not evident and magnetic hysteresis for applied field and stress is shown to be coupled. A thermodynamic model is formulated for 3-D magnetization and strain. It employs a stress, field, and direction dependent hysteron that has an instantaneous loss mechanism, similar to Coulomb-friction or Preisach-type models. Stochastic homogenization is utilized to account for the smoothing effect that material inhomogeneities have on bulk processes. - Highlights: ► We conduct coupled experiments and develop nonlinear thermodynamic models for magnetostrictive iron–gallium (Galfenol) alloys. ► The measurements show unexpected kinematic reversibility in the magnetomechanical coupling. ► This is in contrast with the magnetomechanical coupling in steel which is both thermodynamically and kinematically irreversible. ► The model accurately describes the measurements and provides a framework for understanding hysteresis in ferromagnetic materials which exhibit kinematically reversible magnetomechanical coupling.

  10. Magnetic fluid hyperthermia probed by both calorimetric and dynamic hysteresis measurements

    Science.gov (United States)

    Guibert, Clément; Fresnais, Jérôme; Peyre, Véronique; Dupuis, Vincent

    2017-01-01

    In this paper, we report an investigation of magnetic fluid hyperthermia (MFH) using combined calorimetric and newly implemented dynamic hysteresis measurements for two sets of well characterized size-sorted maghemite nanoparticles (with diameters of about 10 nm and 20 nm) dispersed in water and in glycerol. Our primary goal was to assess the influence of viscosity on the heating efficiency of magnetic nanoparticles described in terms of specific loss power (SLP or specific absorption rate, SAR) and dynamic hysteresis. In particular, we aimed to investigate how this SLP depends on the transition from Néelian to Brownian behavior of nanoparticles expected to occur between 10 nm and 20 nm (for maghemite) and dependent on the viscosity. While we observed a good agreement between calorimetric and dynamic hysteresis measurements, we found that the SLP measured for the different systems do not depend noticeably on the viscosity of solvent. Calculations performed according to Rosensweig's linear model [1] allow us to quantitatively reproduce our results at low field intensities, provided we use a value for the magnetic anisotropy constant much smaller than the one commonly used in the literature. This raises the question of the temperature dependance of the magnetic anisotropy constant and its relevance for a quantitative description of MFH.

  11. Magnetic hysteresis and complex susceptibility as measures of ac losses in a multifilamentary NbTi superconductor

    International Nuclear Information System (INIS)

    Goldfarb, R.B.; Clark, A.F.

    1985-01-01

    Magnetization and ac susceptibility of a standard NbTi superconductor were measured as a function of longitudinal dc magnetic field. The ac-field-amplitude and frequency dependences of the complex susceptibility are examined. The magnetization is related to the susceptibility by means of a theoretical derivation based on the field dependence of the critical current density. Hysteresis losses, obtained directly from dc hysteresis loops and derived theoretically from ac susceptibility and critical current density, were in reasonable agreement

  12. Nondestructive inspection of ductile cast iron by measurement of minor magnetic hysteresis loops

    Czech Academy of Sciences Publication Activity Database

    Vértesy, G.; Uchimoto, T.; Takagi, T.; Tomáš, Ivan

    2010-01-01

    Roč. 659, č. 9 (2010), 355-360 ISSN 0255-5476 R&D Projects: GA ČR GA101/09/1323; GA AV ČR 1QS100100508 Institutional research plan: CEZ:AV0Z10100520 Keywords : magnetic NDE * magnetic adaptive testing * cast iron * magnetic hysteresis Subject RIV: BM - Solid Matter Physics ; Magnetism

  13. Local hysteresis loops measurements on irradiated FeSiB patterned dots by magnetic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Coïsson, M., E-mail: m.coisson@inrim.it [INRIM, Electromagnetism Division, strada delle Cacce 91, 10135 Torino (Italy); Barrera, G. [INRIM, Electromagnetism Division, strada delle Cacce 91, 10135 Torino (Italy); Università di Torino, Dipartimento di Chimica, via P. Giuria 9, 10125 Torino (Italy); Celegato, F.; Enrico, E.; Olivetti, E.S.; Tiberto, P.; Vinai, F. [INRIM, Electromagnetism Division, strada delle Cacce 91, 10135 Torino (Italy)

    2015-01-01

    Magnetic Force Microscopy (MFM) has been exploited to develop a technique capable of investigating the field-dependent magnetisation reversal processes in patterned systems, allowing the full reconstruction of a local hysteresis loop. Fe–Si–B dots with a lateral size of 6μm and a thickness of 250 nm have been prepared by sputtering and optical lithography. In the as-prepared state, the dots are characterised by a dense stripe domain configuration, clearly visible at the MFM. Subsequently, the dots have been thinned by means of exposition to a focussed ion beam, consisting of Ga{sup +} ions having an energy of 30 keV. The local hysteresis loops have been measured by means of the MFM-derived technique. The progressive thinning of the dots results in the disappearance of the perpendicular anisotropy responsible for the dense stripe domain configuration, with the dominance of the shape anisotropy for thickness values below ≈70nm. The results are consistent with the spin reorientation transition effect studied on similar systems in the form of continuous thin films.

  14. Local hysteresis loops measurements on irradiated FeSiB patterned dots by magnetic force microscopy

    International Nuclear Information System (INIS)

    Coïsson, M.; Barrera, G.; Celegato, F.; Enrico, E.; Olivetti, E.S.; Tiberto, P.; Vinai, F.

    2015-01-01

    Magnetic Force Microscopy (MFM) has been exploited to develop a technique capable of investigating the field-dependent magnetisation reversal processes in patterned systems, allowing the full reconstruction of a local hysteresis loop. Fe–Si–B dots with a lateral size of 6μm and a thickness of 250 nm have been prepared by sputtering and optical lithography. In the as-prepared state, the dots are characterised by a dense stripe domain configuration, clearly visible at the MFM. Subsequently, the dots have been thinned by means of exposition to a focussed ion beam, consisting of Ga + ions having an energy of 30 keV. The local hysteresis loops have been measured by means of the MFM-derived technique. The progressive thinning of the dots results in the disappearance of the perpendicular anisotropy responsible for the dense stripe domain configuration, with the dominance of the shape anisotropy for thickness values below ≈70nm. The results are consistent with the spin reorientation transition effect studied on similar systems in the form of continuous thin films

  15. Hysteresis phenomena in hydraulic measurement

    International Nuclear Information System (INIS)

    Ran, H J; Farhat, M; Luo, X W; Chen, Y L; Xu, H Y

    2012-01-01

    Hysteresis phenomena demonstrate the lag between the generation and the removal of some physical phenomena. This paper studies the hysteresis phenomena of the head-drop in a scaled model pump turbine using experiment test and CFD methods. These lag is induced by complicated flow patterns, which influenced the reliability of rotating machine. Keeping the same measurement procedure is concluded for the hydraulic machine measurement.

  16. Hysteresis effects in the cores of particle accelerator magnets

    CERN Document Server

    AUTHOR|(CDS)2086181; Schoerling, Daniel

    A study of the hysteresis effects in the cores of particle accelerator magnets has been performed in the framework of the work presented in this thesis. This study has been focused on normal conducting particle accelerator magnets whose cores are manufactured using ferromagnetic materials. The magnetic circuits have been modelled using the developed models: one model for the magnetic circuit and one for the magnetization of the material in the core. The parameters of the magnetic circuit model have been identified with the help of simulations which rely on the finite element method (Opera 3D), while the parameters of the magnetic hysteresis model have been identified through experimental measurements performed using a method developed in the framework of this work. The modelling results have been validated by means of experimental measurements performed on two magnets: one small size magnet which has been specifically designed and manufactured, and one magnet which is currently used in a particle accelerator ...

  17. Low Field Magnetic and Thermal Hysteresis in Antiferromagnetic Dysprosium

    Directory of Open Access Journals (Sweden)

    Iuliia Liubimova

    2017-06-01

    Full Text Available Magnetic and thermal hysteresis (difference in magnetic properties on cooling and heating have been studied in polycrystalline Dy (dysprosium between 80 and 250 K using measurements of the reversible Villari effect and alternating current (AC susceptibility. We argue that measurement of the reversible Villari effect in the antiferromagnetic phase is a more sensitive method to detect magnetic hysteresis than the registration of conventional B(H loops. We found that the Villari point, recently reported in the antiferromagnetic phase of Dy at 166 K, controls the essential features of magnetic hysteresis and AC susceptibility on heating from the ferromagnetic state: (i thermal hysteresis in AC susceptibility and in the reversible Villari effect disappears abruptly at the temperature of the Villari point; (ii the imaginary part of AC susceptibility is strongly frequency dependent, but only up to the temperature of the Villari point; (iii the imaginary part of the susceptibility drops sharply also at the Villari point. We attribute these effects observed at the Villari point to the disappearance of the residual ferromagnetic phase. The strong influence of the Villari point on several magnetic properties allows this temperature to be ranked almost as important as the Curie and Néel temperatures in Dy and likely also for other rare earth elements and their alloys.

  18. The rotational hysteresis losses in thin films with unidirectional magnetic anisotropy

    Science.gov (United States)

    Mucha, J. M.; Vatskichev, L.; Vatskicheva, M.

    1992-03-01

    Using the Planar Hall Effect (PHE) the rotational hysteresis losses in NiFeGe thin magnetic films were measured. The calculation of the critical field for magnetization and rotational hysteresis losses based on extended Stoner-Wohlfarth theory including an exchange magnetic field is given.

  19. Modeling of hysteresis in magnetic multidomains

    International Nuclear Information System (INIS)

    Cardelli, E.; Carpentieri, M.; Faba, A.; Finocchio, G.

    2014-01-01

    In this paper, the analysis of multi-domain nanostructures is made by means of numerical approaches. The Landau–Lifshitz–Gilbert LLG equation is used to compute the magnetic hysteresis loops for different alternate scalar polarizations. The data computed are then used to identify the parameters of a phenomenological model, based on the extension of the Preisach model in 2-D. The identification in this case is the evaluation of the size and the position of the hysterons in the H-plane. Each hysteron is associated to a domain of the nanostructure and the assembly of hysterons reproduces with satisfactory accuracy the hysteretic behavior of the nanostructure computed by the LLG equation with an extremely reduced computational time. Some possible relationships between the magnetization nanostructure and the parameters of the hysteron are suggested. These relationship should be used for a “blind” prediction of the magnetization state of much larger magnetic structures, whose computation using the LLG equation is not possible in practice due to the enormous computational time, supposing that magnetic structures with the same aspect ratio exhibit a similar distribution of magnetic domains. The theory is applied here to an example of Permalloy nanostructure

  20. Specific absorption rate dependence on temperature in magnetic field hyperthermia measured by dynamic hysteresis losses (ac magnetometry)

    Science.gov (United States)

    Garaio, Eneko; Sandre, Olivier; Collantes, Juan-Mari; Garcia, Jose Angel; Mornet, Stéphane; Plazaola, Fernando

    2015-01-01

    Magnetic nanoparticles (NPs) are intensively studied for their potential use for magnetic hyperthermia, a treatment that has passed a phase II clinical trial against severe brain cancer (glioblastoma) at the end of 2011. Their heating power, characterized by the ‘specific absorption rate (SAR)’, is often considered temperature independent in the literature, mainly because of the difficulties that arise from the measurement methodology. Using a dynamic magnetometer presented in a recent paper, we measure here the thermal dependence of SAR for superparamagnetic iron oxide (maghemite) NPs of four different size-ranges corresponding to mean diameters around 12 nm, 14 nm, 15 nm and 16 nm. The article reports a parametrical study extending from 10 to 60 {}^\\circ C in temperature, from 75 to 1031 kHz in frequency, and from 2 to 24 kA m-1 in magnetic field strength. It was observed that SAR values of smaller NPs decrease with temperature whereas for the larger sample (16 nm) SAR values increase with temperature. The measured variation of SAR with temperature is frequency dependent. This behaviour is fully explained within the scope of linear response theory based on Néel and Brown relaxation processes, using independent magnetic measurements of the specific magnetization and the magnetic anisotropy constant. A good quantitative agreement between experimental values and theoretical values is confirmed in a tri-dimensional space that uses as coordinates the field strength, the frequency and the temperature.

  1. Magnetic transmission gear finite element simulation with iron pole hysteresis

    Science.gov (United States)

    Filippini, Mattia; Alotto, Piergiorgio; Glehn, Gregor; Hameyer, Kay

    2018-04-01

    Ferromagnetic poles in a magnetic transmission gear require particular attention during their design process. Usually, during the numerical simulation of these devices the effects of hysteresis for loss estimation are neglected and considered only during post-processing calculations. Since the literature lacks hysteresis models, this paper adopts a homogenized hysteretic model able to include eddy current and hysteresis losses in 2D laminated materials for iron poles. In this article the results related to the hysteresis in a magnetic gear are presented and compared to the non-hysteretic approach.

  2. Carnot cycle for magnetic materials: The role of hysteresis

    International Nuclear Information System (INIS)

    Sasso, Carlo P.; Basso, Vittorio; LoBue, Martino; Bertotti, Giorgio

    2006-01-01

    The role of hysteresis in a refrigeration thermodynamic cycle involving ferromagnetic materials is discussed. A model allowing to calculate magnetization, entropy and entropy production in systems with hysteresis is used to compute a non-ideal Carnot cycle performed on a ferromagnetic material

  3. A challenging hysteresis operator for the simulation of Goss-textured magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Cardelli, Ermanno [Dipartimento di Ingegneria, Università di Perugia, Via G. Duranti, 67, 06125 Perugia (Italy); Centre for Electric and Magnetic Applied Research, Perugia (Italy); Faba, Antonio [Centre for Electric and Magnetic Applied Research, Perugia (Italy); Polo Didattico Scientifico di Terni, Strada Pentima Bassa n. 4, 05100 Terni (Italy); Laudani, Antonino [Università Roma tre, Via Ostiense, 159, 00154 Roma (Italy); Pompei, Michele [Dipartimento di Ingegneria, Università di Perugia, Via G. Duranti, 67, 06125 Perugia (Italy); Quondam Antonio, Simone, E-mail: simonequondam87@gmail.com [Dipartimento di Ingegneria, Università di Perugia, Via G. Duranti, 67, 06125 Perugia (Italy); Fulginei, Francesco Riganti; Salvini, Alessandro [Università Roma tre, Via Ostiense, 159, 00154 Roma (Italy)

    2017-06-15

    Highlights: • New 2-D hysteresis operator for the simulation of Goss-textured ferromagnets at macromagnetic scale-length. • The operator is derived from the classic Stoner–Wohlfarth but the in-plane magnetic anisotropy is cubic. • The single hysteron model is defined exploiting only one “moving” hysteresis operator. • Results are especially promising for FEM based calculations, where the magnetization state in each point must be recalculated at each time step. • Numerical accuracy is proved by comparison with measured data. - Abstract: A new hysteresis operator for the simulation of Goss-textured ferromagnets is here defined. The operator is derived from the classic Stoner–Wohlfarth model, where the anisotropy energy is assumed to be cubic instead of uniaxial, in order to reproduce the magnetic behavior of Goss textured ferromagnetic materials, such as grain-oriented Fe–Si alloys, Ni–Fe alloys, and Ni–Co alloys. A vector hysteresis model based on a single hysteresis operator is then implemented and used for the prediction of the rotational magnetizations that have been measured in a sample of grain-oriented electrical steel. This is especially promising for FEM based calculations, where the magnetization state in each point must be recalculated at each time step. Finally, the computed loops, as well as the magnetic losses, are compared to the measured data.

  4. Molecular magnetic hysteresis at 60 kelvin in dysprosocenium

    Science.gov (United States)

    Goodwin, Conrad A. P.; Ortu, Fabrizio; Reta, Daniel; Chilton, Nicholas F.; Mills, David P.

    2017-08-01

    Lanthanides have been investigated extensively for potential applications in quantum information processing and high-density data storage at the molecular and atomic scale. Experimental achievements include reading and manipulating single nuclear spins, exploiting atomic clock transitions for robust qubits and, most recently, magnetic data storage in single atoms. Single-molecule magnets exhibit magnetic hysteresis of molecular origin—a magnetic memory effect and a prerequisite of data storage—and so far lanthanide examples have exhibited this phenomenon at the highest temperatures. However, in the nearly 25 years since the discovery of single-molecule magnets, hysteresis temperatures have increased from 4 kelvin to only about 14 kelvin using a consistent magnetic field sweep rate of about 20 oersted per second, although higher temperatures have been achieved by using very fast sweep rates (for example, 30 kelvin with 200 oersted per second). Here we report a hexa-tert-butyldysprosocenium complex—[Dy(Cpttt)2][B(C6F5)4], with Cpttt = {C5H2tBu3-1,2,4} and tBu = C(CH3)3—which exhibits magnetic hysteresis at temperatures of up to 60 kelvin at a sweep rate of 22 oersted per second. We observe a clear change in the relaxation dynamics at this temperature, which persists in magnetically diluted samples, suggesting that the origin of the hysteresis is the localized metal-ligand vibrational modes that are unique to dysprosocenium. Ab initio calculations of spin dynamics demonstrate that magnetic relaxation at high temperatures is due to local molecular vibrations. These results indicate that, with judicious molecular design, magnetic data storage in single molecules at temperatures above liquid nitrogen should be possible.

  5. Influence of tensile stress and frequency on the longitudinal magnetic hysteresis of amorphous wires

    International Nuclear Information System (INIS)

    Torres, Carlos; Maria Munoz, Jose; Hernandez-Gomez, Pablo; Francisco, Carlos de

    2010-01-01

    This work studies the longitudinal magnetic hysteresis of amorphous wires with different Fe or Co compositions through an external magnetic field in the axial direction. Measurements have been carried out with the help of a digitally processed system in the 50 Hz-1 kHz frequency range. In addition, the influence of different tensile stresses has been also analyzed. The results show that both parameters change considerably the magnetic hysteresis of the wires but in a different way depending on their composition. This behaviour has been interpreted in terms of the different domain distribution associated with the opposite sign of the magnetostriction for Fe and Co-based wires, respectively.

  6. Fourier transform and controlling of flux in scalar hysteresis measurement

    International Nuclear Information System (INIS)

    Kuczmann, Miklos

    2008-01-01

    The paper deals with a possible realization of eliminating the effect of noise in scalar hysteresis measurements. The measured signals have been transformed into the frequency domain, and, after applying digital filter, the spectrums of the filtered signals have been transformed back to the time domain. The proposed technique results in an accurate noise-removal algorithm. The paper illustrates a fast controlling algorithm applying the inverse of the actually measured hysteresis loop, and another proportional one to measure distorted flux pattern. By developing the mentioned algorithms, it aims at the controlling of a more complicated phenomena, i.e. measuring the vector hysteresis characteristics

  7. Magnetization configurations and hysteresis loops of small permalloy ellipses

    International Nuclear Information System (INIS)

    Schneider, M; Liszkowski, J; Rahm, M; Wegscheider, W; Weiss, D; Hoffmann, H; Zweck, J

    2003-01-01

    We investigated systematically the easy axis magnetization reversal of 20 nm thick permalloy ellipses with a fixed major axis of 1.47 μm and minor axes of 0.22-1.47 μm. Lorentz transmission electron microscopy was used to image the micromagnetic configurations during magnetization reversal. Hysteresis loops of single ellipses were recorded by means of micro-Hall magnetometry and could be traced back to certain reversal mechanisms observed by Lorentz microscopy. In most cases, the magnetization reversal is initiated by the evolution of a magnetization buckling, followed by the formation of a single, a double, or a trapped vortex configuration. For ellipses with high aspect ratio (length-to-width ratio), the magnetization switches in the reversed magnetic field without creation of a stable vortex configuration. Our experiments show that the characteristic field values for vortex creation, single vortex annihilation, and switching strongly depend on the shape anisotropy of the elements

  8. Magnetic dipolar ordering and hysteresis of geometrically defined nanoparticle clusters

    DEFF Research Database (Denmark)

    Kure, Mathias; Beleggia, Marco; Frandsen, Cathrine

    2017-01-01

    Magnetic nanoparticle clusters have several biomedical and engineering applications, and revealing the basic interplay between particle configuration and magnetic properties is important for tuning the clusters for specific uses. Here, we consider the nanoparticles as macrospins and use computer...... of the polyhedra, the central moment relaxes along one of the principal axes and induces partial alignment of the surrounding moments. The resulting net moment is up to nearly four times that of the single moment added. Furthermore, we model quasi-static hysteresis loops for structures with and without a central...

  9. Design for Fermilab main injector magnet ramps which account for hysteresis

    International Nuclear Information System (INIS)

    Brown, B.C.; Bhat, C.M.; Harding, D.J.; Martin, P.S.; Wu, G.

    1997-05-01

    Although the dominant fields in accelerator electromagnets are proportional to the excitation current, precise control of accelerator parameters requires a detailed understanding of the fields in Main Injector magnets including contribution from eddy currents, magnet saturation, and hysteresis. Operation for decelerating beam makes such considerations particularly significant. Analysis of magnet measurements and design of control system software is presented. Field saturation and its effects on low field hysteresis are accounted for in specifying the field ramps for dipole, quadrupole and sextupole magnets. Some simplifying assumptions are made which are accepted as limitations on the required ramp sequences. Specifications are provided for relating desired field ramps to required current ramps for the momentum, tune, and chromaticity control

  10. Surface magnetic field measurement with magnetic shielding

    Czech Academy of Sciences Publication Activity Database

    Perevertov, Oleksiy

    2010-01-01

    Roč. 61, č. 7 (2010), 66-68 ISSN 1335-3632 Grant - others:AVČR(CZ) M100100906 Institutional research plan: CEZ:AV0Z10100520 Keywords : magnetic hysteresis * magnetic field measurement * magnetic shielding * extrapolation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.270, year: 2010

  11. Hysteresis losses of magnetic nanoparticle powders in the single domain size range

    International Nuclear Information System (INIS)

    Dutz, S.; Hergt, R.; Muerbe, J.; Mueller, R.; Zeisberger, M.; Andrae, W.; Toepfer, J.; Bellemann, M.E.

    2007-01-01

    Magnetic iron oxide nanoparticle powders were investigated in order to optimise the specific hysteresis losses for biomedical heating applications. Different samples with a mean particle size in the transition range from superparamagnetic to ferromagnetic behaviour (i.e. 10-100 nm) were prepared by two different chemical precipitation routes. Additionally, the influence of milling and annealing on hysteresis losses of the nanoparticles was investigated. Structural investigations of the samples were carried out by X-ray diffraction, measurement of specific surface area, and scanning and transmission electron microscopy. The dependence of hysteresis losses of minor loops on the field amplitude was determined using vibrating sample magnetometry and caloric measurements. For small field amplitudes, a power law was found which changes into saturation at amplitudes well above the coercive field. Maximum hysteresis losses of 6.6 J/kg per cycle were observed for milled powder. For field amplitudes below about 10 kA/m, which are especially interesting for medical and technical applications, hysteresis losses of all investigated powders were at least by one order of magnitude lower than reported for magnetosomes of comparable size

  12. Magnetic hysteresis and domain wall dynamics in single chain magnets with antiferromagnetic interchain coupling

    Energy Technology Data Exchange (ETDEWEB)

    Bukharov, A A; Ovchinnikov, A S; Baranov, N V [Department of Physics, Ural State University, Ekaterinburg, 620083 (Russian Federation); Inoue, K [Institute for Advanced Materials Research, Hiroshima University, Hiroshima (Japan)

    2010-11-03

    Using Monte Carlo simulations we investigate magnetic hysteresis in two- and three-dimensional systems of weakly antiferromagnetically coupled spin chains based on a scenario of domain wall (kink) motion within the chains. By adapting the model of walkers to simulate the domain wall dynamics and using the Ising-like dipole-dipole model, we study the effects of interchain coupling, temperature and anisotropy axis direction on hysteresis curves.

  13. Hysteresis and Temperature Dependency of Moisture Sorption – New Measurements

    DEFF Research Database (Denmark)

    Rode, Carsten; Hansen, Kurt Kielsgaard

    2011-01-01

    measurements of hysteresis and temperature dependency of the moisture sorption characteristics of three different porous building materials: aerated concrete, cement paste and spruce. Scanning curves are measured for all three materials where periods with adsorption and desorption interrupt each other...... intermittently. For one of the materials, aerated concrete, the sorption curves are determined at three different temperatures....

  14. Application of magnetomechanical hysteresis modeling to magnetic techniques for monitoring neutron embrittlement and biaxial stress

    International Nuclear Information System (INIS)

    Sablik, M.J.; Kwun, H.; Rollwitz, W.L.; Cadena, D.

    1992-01-01

    The objective is to investigate experimentally and theoretically the effects of neutron embrittlement and biaxial stress on magnetic properties in steels, using various magnetic measurement techniques. Interaction between experiment and modeling should suggest efficient magnetic measurement procedures for determining neutron embrittlement biaxial stress. This should ultimately assist in safety monitoring of nuclear power plants and of gas and oil pipelines. In the first six months of this first year study, magnetic measurements were made on steel surveillance specimens from the Indian Point 2 and D.C. Cook 2 reactors. The specimens previously had been characterized by Charpy tests after specified neutron fluences. Measurements now included: (1) hysteresis loop measurement of coercive force, permeability and remanence, (2) Barkhausen noise amplitude; and (3) higher order nonlinear harmonic analysis of a 1 Hz magnetic excitation. Very good correlation of magnetic parameters with fluence and embrittlement was found for specimens from the Indian Point 2 reactor. The D.C. Cook 2 specimens, however showed poor correlation. Possible contributing factors to this are: (1) metallurgical differences between D.C. Cook 2 and Indian Point 2 specimens; (2) statistical variations in embrittlement parameters for individual samples away from the stated men values; and (3) conversion of the D.C. Cook 2 reactor to a low leakage core configuration in the middle of the period of surveillance. Modeling using a magnetomechanical hysteresis model has begun. The modeling will first focus on why Barkhausen noise and nonlinear harmonic amplitudes appear to be better indicators of embrittlement than the hysteresis loop parameters

  15. Hysteresis in magnetic materials: the role of structural disorder, thermal relaxation, and dynamic effects

    International Nuclear Information System (INIS)

    Bertotti, G.; Basso, V.; Beatrice, C.; LoBue, M.; Magni, A.; Tiberto, P.

    2001-01-01

    An overview is given of the present understanding of hysteresis phenomena in magnetic materials. The problem is addressed from three approximate viewpoints: the connection between rate-independent hysteresis and micromagnetics; the modifications brought into this picture by thermal relaxation effects; the role of rate-dependent magnetization mechanisms, like eddy-current-damped domain wall motion

  16. A neural approach for the numerical modeling of two-dimensional magnetic hysteresis

    International Nuclear Information System (INIS)

    Cardelli, E.; Faba, A.; Laudani, A.; Riganti Fulginei, F.; Salvini, A.

    2015-01-01

    This paper deals with a neural network approach to model magnetic hysteresis at macro-magnetic scale. Such approach to the problem seems promising in order to couple the numerical treatment of magnetic hysteresis to FEM numerical solvers of the Maxwell's equations in time domain, as in case of the non-linear dynamic analysis of electrical machines, and other similar devices, making possible a full computer simulation in a reasonable time. The neural system proposed consists of four inputs representing the magnetic field and the magnetic inductions components at each time step and it is trained by 2-d measurements performed on the magnetic material to be modeled. The magnetic induction B is assumed as entry point and the output of the neural system returns the predicted value of the field H at the same time step. A suitable partitioning of the neural system, described in the paper, makes the computing process rather fast. Validations with experimental tests and simulations for non-symmetric and minor loops are presented

  17. Modeling of quasistatic magnetic hysteresis with feed-forward neural networks

    International Nuclear Information System (INIS)

    Makaveev, Dimitre; Dupre, Luc; De Wulf, Marc; Melkebeek, Jan

    2001-01-01

    A modeling technique for rate-independent (quasistatic) scalar magnetic hysteresis is presented, using neural networks. Based on the theory of dynamic systems and the wiping-out and congruency properties of the classical scalar Preisach hysteresis model, the choice of a feed-forward neural network model is motivated. The neural network input parameters at each time step are the corresponding magnetic field strength and memory state, thereby assuring accurate prediction of the change of magnetic induction. For rate-independent hysteresis, the current memory state can be determined by the last extreme magnetic field strength and induction values, kept in memory. The choice of a network training set is motivated and the performance of the network is illustrated for a test set not used during training. Very accurate prediction of both major and minor hysteresis loops is observed, proving that the neural network technique is suitable for hysteresis modeling. [copyright] 2001 American Institute of Physics

  18. Magnetoabsorption and magnetic hysteresis in Ni ferrite nanoparticles

    Directory of Open Access Journals (Sweden)

    Torres C.

    2013-01-01

    Full Text Available Nickel ferrite nanoparticles were prepared by a modified sol-gel technique employing coconut oil, and then annealed at different temperatures in 400-1200 °C range. This route of preparation has revealed to be one efficient and cheap technique to obtain high quality nickel ferrite nanosized powder. Sample particles sizes obtained with XRD data and Scherrer’s formula lie in 13 nm to 138 nm, with increased size with annealing temperature. Hysteresis loops have been obtained at room temperature with an inductive method. Magnetic field induced microwave absorption in nanoscale ferrites is a recent an active area of research, in order to characterize and explore potential novel applications. In the present work microwave magnetoabsorption data of the annealed nickel ferrite nanoparticles are presented. These data have been obtained with a system based on a network analyzer that operates in the frequency range 0 - 8.5 GHz. At fields up to 400 mT we can observe a peak according to ferromagnetic resonance theory. Sample annealed at higher temperature exhibits different absorption, coercivity and saturation magnetization figures, revealing its multidomain character.

  19. Magnetic hysteresis and refrigeration capacity of Ni–Mn–Ga alloys near Martensitic transformation

    International Nuclear Information System (INIS)

    Bin, Fu; Yi, Long; Jing-Fang, Duan; Chao-Lun, Wang; Yong-Qin, Chang; Rong-Chang, Ye; Guang-Heng, Wu

    2010-01-01

    This paper studies the magnetic hysteresis and refrigeration capacity of Ni-Mn-Ga alloys in detail during heating and cooling isothermal magnetisation processes. The Ni-Mn-Ga alloys show larger magnetic hysteresis when they transform from austenite to martensite, but smaller magnetic hysteresis when they transform from martensite to austenite. This behaviour is independent of either the pure Ni-Mn-Ga alloys or the alloys doped with other elements. Because of the existence of the magnetic hysteresis, the relation between the magnetic entropy change and refrigeration capacity is not simply linear. For practical consideration, magnetocaloric effect of Ni-Mn-Ga alloys should be investigated both on cooling and heating processes. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  20. Hysteresis of critical currents of superconducting bridges in low perpendicular magnetic fields

    International Nuclear Information System (INIS)

    Aomine, T.; Tanaka, E.; Yamasaki, S.; Tani, K.; Yonekura, A.

    1989-01-01

    Hysteresis of critical currents I c of superconducting bridges with In, Nb, and NbN has been studied in low perpendicular magnetic fields. Influences of bridge geometry, small field sweep, trapped flux, and bombardment of argon ions on the hysteresis were made clear. The experimental results suggest that the edge pinning and trapped flux in the bank of bridges are associated with the hysteresis. The peak value of I c of NbN bridges, as well as granular Al and In bridges reported before, in decreasing fields agrees with the calculated pair-breaking current. The origin of the hysteresis is discussed

  1. Transport hysteresis and zonal flow stimulation in magnetized plasmas

    Science.gov (United States)

    Gravier, E.; Lesur, M.; Reveille, T.; Drouot, T.; Médina, J.

    2017-12-01

    A hysteresis in the relationship between zonal flows and electron heating is observed numerically by using gyrokinetic simulations in fusion plasmas. As the electron temperature increases, a first transition occurs, at a given electron/ion temperature ratio, above which zonal flows are much weaker than before the transition, leading to a poorly confined plasma. Beyond this transition, even if the electron temperature is lowered to a moderate value, the plasma fails to recover a dynamic state with strong zonal flows. Then, as the electron temperature decreases further, a new transition appears, at a temperature lower than the first transition, below which the zonal flows are stronger than they were initially. The confinement of the plasma and the heat flux are thus found to be sensitive to the history of the magnetized plasma. These transitions are associated with large exchanges of energy between the modes corresponding to instabilities ( m> 0 ) and zonal flows ( m = 0 ). We also observe that up to the first transition it is possible to use a control method to stimulate the appearance of zonal flows and therefore the confinement of the plasma. Beyond that transition, this control method is no longer effective.

  2. Magnetic hysteresis of cerium doped bismuth ferrite thin films

    International Nuclear Information System (INIS)

    Gupta, Surbhi; Tomar, Monika; Gupta, Vinay

    2015-01-01

    The influence of Cerium doping on the structural and magnetic properties of BiFeO 3 thin films have been investigated. Rietveld refinement of X-ray diffraction data and successive de-convolution of Raman scattering spectra of Bi 1−x Ce x FeO 3 (BCFO) thin films with x=0–0.20 reflect the single phase rhombohedral (R3c) formation for x<0.08, whereas concentration-driven gradual structural phase transition from rhombohedral (R3c) to partial tetragonal (P4mm) phase follows for x≥0.08. All low wavenumber Raman modes (<300 cm −1 ) showed a noticeable shift towards higher wavenumber with increase in doping concentration, except Raman E-1 mode (71 cm −1 ), shows a minor shift. Sudden evolution of Raman mode at 668 cm −1 , manifested as A 1 -tetragonal mode, accompanied by the shift to higher wavenumber with increase in doping concentration (x) affirm partial structural phase transition. Anomalous wasp waist shaped (M–H) hysteresis curves with improved saturation magnetization (M s ) for BCFO thin films is attributed to antiferromagnetic interaction/hybridization between Ce 4f and Fe 3d electronic states. The contribution of both hard and soft phase to the total coercivity is calculated. Polycrystalline Bi 0.88 Ce 0.12 FeO 3 thin film found to exhibit better magnetic properties with M s =15.9 emu/g without any impure phase. - Highlights: • Synthesis of single phase Bi 1−x Ce x FeO 3 thin films with (x=0–0.2) on cost effective corning glass and silicon substrates using CSD technique. • Structural modification studies using Rietveld refinement of XRD and de-convolution of Raman spectra revealed partial phase transition from rhombohedral (R3c) to tetragonal (P4mm) phase. • Possible reasons for origin of pinched magnetic behavior of BCFO thin films are identified. • Contribution of both hard and soft magnetic phase in coercivity of BCFO thin films is calculated and practical applications of such materials exhibiting pinching behavior are conferred

  3. Magnetic hysteresis of cerium doped bismuth ferrite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Surbhi [Department of Physics and Astrophysics, University of Delhi (India); Tomar, Monika [Physics Department, Miranda House, University of Delhi (India); Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi (India)

    2015-03-15

    The influence of Cerium doping on the structural and magnetic properties of BiFeO{sub 3} thin films have been investigated. Rietveld refinement of X-ray diffraction data and successive de-convolution of Raman scattering spectra of Bi{sub 1−x}Ce{sub x}FeO{sub 3} (BCFO) thin films with x=0–0.20 reflect the single phase rhombohedral (R3c) formation for x<0.08, whereas concentration-driven gradual structural phase transition from rhombohedral (R3c) to partial tetragonal (P4mm) phase follows for x≥0.08. All low wavenumber Raman modes (<300 cm{sup −1}) showed a noticeable shift towards higher wavenumber with increase in doping concentration, except Raman E-1 mode (71 cm{sup −1}), shows a minor shift. Sudden evolution of Raman mode at 668 cm{sup −1}, manifested as A{sub 1}-tetragonal mode, accompanied by the shift to higher wavenumber with increase in doping concentration (x) affirm partial structural phase transition. Anomalous wasp waist shaped (M–H) hysteresis curves with improved saturation magnetization (M{sub s}) for BCFO thin films is attributed to antiferromagnetic interaction/hybridization between Ce 4f and Fe 3d electronic states. The contribution of both hard and soft phase to the total coercivity is calculated. Polycrystalline Bi{sub 0.88}Ce{sub 0.12}FeO{sub 3} thin film found to exhibit better magnetic properties with M{sub s}=15.9 emu/g without any impure phase. - Highlights: • Synthesis of single phase Bi{sub 1−x}Ce{sub x}FeO{sub 3} thin films with (x=0–0.2) on cost effective corning glass and silicon substrates using CSD technique. • Structural modification studies using Rietveld refinement of XRD and de-convolution of Raman spectra revealed partial phase transition from rhombohedral (R3c) to tetragonal (P4mm) phase. • Possible reasons for origin of pinched magnetic behavior of BCFO thin films are identified. • Contribution of both hard and soft magnetic phase in coercivity of BCFO thin films is calculated and practical

  4. A Novel Hysteresis Model of Magnetic Field Strength Determined by Magnetic Induction Intensity for Fe-3% Si Electrical Steel Applied in Cigarette Making Machines

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2016-01-01

    Full Text Available Hysteresis characteristics of grain-oriented electrical steel were studied through the hysteresis loop. Existing hysteresis fitting simulation methods were summarized, and new Fe-3% Si grain-oriented electrical steel hysteresis loop model was proposed. Undetermined coefficients of the magnetic field intensity and magnetic flux density were determined by both the fixed angle method and the least squares method, and the hysteresis loop model was validated with high fitting degree by experimental data.

  5. Simulation of magnetic hysteresis loops and magnetic Barkhausen noise of α-iron containing nonmagnetic particles

    International Nuclear Information System (INIS)

    Li, Yi; Li, Qiulin; Liu, Wei; Xu, Ben; Hu, Shenyang; Li, Yulan

    2015-01-01

    The magnetic hysteresis loops and Barkhausen noise of a single α-iron with nonmagnetic particles are simulated to investigate into the magnetic hardening due to Cu-rich precipitates in irradiated reactor pressure vessel (RPV) steels. Phase field method basing Landau-Lifshitz-Gilbert (LLG) equation is used for this simulation. The results show that the presence of the nonmagnetic particle could result in magnetic hardening by making the nucleation of reversed domains difficult. The coercive field is found to increase, while the intensity of Barkhausen noise voltage is decreased when the nonmagnetic particle is introduced. Simulations demonstrate the impact of nucleation field of reversed domains on the magnetization reversal behavior and the magnetic properties

  6. Simulations of magnetic hysteresis loops for dual layer recording media

    Science.gov (United States)

    Fal, T. J.; Plumer, M. L.; Whitehead, J. P.; Mercer, J. I.; van Ek, J.; Srinivasan, K.

    2013-05-01

    A Kinetic Monte-Carlo algorithm is applied to examine MH loops of dual-layer magnetic recording media at finite temperature and long time scales associated with typical experimental measurements. In contrast with standard micromagnetic simulations, which are limited to the ns-μs time regime, our approach allows for the direct calculation of magnetic configurations over periods from minutes to years. The model is used to fit anisotropy and coupling parameters to experimental data on exchange-coupled composite media which are shown to deviate significantly from standard micromagnetic results. Sensitivities of the loops to anisotropy, inter-layer exchange coupling, temperature, and sweep rate are examined.

  7. Physics behind the magnetic hysteresis loop--a survey of misconceptions in magnetism literature

    International Nuclear Information System (INIS)

    Sung, H.W.F.; Rudowicz, C.

    2003-01-01

    An extensive survey of misinterpretations and misconceptions concerning presentation of the hysteresis loop for ferromagnetic materials occurring in undergraduate textbooks has recently been carried out. As a follow-up, this article provides similar examples, now drawn from recent magnetism literature. The distinction between the two notions of 'coercivity' referred to the B vs. H curve and the M vs. H curve, which turn out to be often confused in textbooks is elucidated. Various misinterpretations and conceptual problems revealed by our survey of recent magnetism-related scientific journals are summarized. In order to counteract the misinterpretations in question, some real examples of hysteresis loops showing the correct characteristics have also been identified in this search. Various ways of presenting units for the same physical quantity, i.e. the SI or cgs units as well as both units mixed, have been revealed in the regular articles. This is a worrying factor, which calls for a concerted action at the level of the whole magnetism community. A number of intricacies and fundamental conceptual problems in magnetism encountered in a recent review are dealt with in a separate note

  8. Computational modeling of magnetic hysteresis with thermal effects

    Czech Academy of Sciences Publication Activity Database

    Kružík, Martin; Valdman, Jan

    2018-01-01

    Roč. 145, č. 1 (2018), s. 90-105 ISSN 0378-4754 R&D Projects: GA ČR GA13-18652S; GA ČR(CZ) GF16-34894L; GA ČR(CZ) GA17-04301S; GA MŠk(CZ) 7AMB16AT015 Institutional support: RVO:67985556 Keywords : Dissipative processes * hysteresis * micromagnetics Subject RIV: BA - General Mathematics Impact factor: 1.218, year: 2016 http://library.utia.cas.cz/separaty/2017/MTR/kruzik-0474872.pdf

  9. Comparison of angular dependence of magnetic Barkhausen noise of hysteresis and initial magnetization curve in API5L steel

    Science.gov (United States)

    Chávez-Gonzalez, A. F.; Martínez-Ortiz, P.; Pérez-Benítez, J. A.; Espina-Hernández, J. H.; Caleyo, F.

    2018-01-01

    This work analyzes the differences between the magnetic Barkhausen noise corresponding to the initial magnetization curve and Barkhausen noise corresponding to one branch of the hysteresis loop in API-5L steel. The outcomes show that the Barkhausen noise signal corresponding to the initial magnetization curve and that corresponding to the hysteresis are significantly different. This difference is due to the presence of different processes of the domain wall dynamics in both phenomena. To study the processes present in magnetization dynamics for an applied field of H > 0, research into the angular dependence of a Barkhausen signal using applied field bands has revealed that a Barkhausen signal corresponding to the initial magnetization curve is more suitable than a Barkhausen signal corresponding to the hysteresis loop.

  10. Magnetic hysteresis at the domain scale of a multi-scale material model for magneto-elastic behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Vanoost, D., E-mail: dries.vanoost@kuleuven-kulak.be [KU Leuven Technology Campus Ostend, ReMI Research Group, Oostende B-8400 (Belgium); KU Leuven Kulak, Wave Propagation and Signal Processing Research Group, Kortrijk B-8500 (Belgium); Steentjes, S. [Institute of Electrical Machines, RWTH Aachen University, Aachen D-52062 (Germany); Peuteman, J. [KU Leuven Technology Campus Ostend, ReMI Research Group, Oostende B-8400 (Belgium); KU Leuven, Department of Electrical Engineering, Electrical Energy and Computer Architecture, Heverlee B-3001 (Belgium); Gielen, G. [KU Leuven, Department of Electrical Engineering, Microelectronics and Sensors, Heverlee B-3001 (Belgium); De Gersem, H. [KU Leuven Kulak, Wave Propagation and Signal Processing Research Group, Kortrijk B-8500 (Belgium); TU Darmstadt, Institut für Theorie Elektromagnetischer Felder, Darmstadt D-64289 (Germany); Pissoort, D. [KU Leuven Technology Campus Ostend, ReMI Research Group, Oostende B-8400 (Belgium); KU Leuven, Department of Electrical Engineering, Microelectronics and Sensors, Heverlee B-3001 (Belgium); Hameyer, K. [Institute of Electrical Machines, RWTH Aachen University, Aachen D-52062 (Germany)

    2016-09-15

    This paper proposes a multi-scale energy-based material model for poly-crystalline materials. Describing the behaviour of poly-crystalline materials at three spatial scales of dominating physical mechanisms allows accounting for the heterogeneity and multi-axiality of the material behaviour. The three spatial scales are the poly-crystalline, grain and domain scale. Together with appropriate scale transitions rules and models for local magnetic behaviour at each scale, the model is able to describe the magneto-elastic behaviour (magnetostriction and hysteresis) at the macroscale, although the data input is merely based on a set of physical constants. Introducing a new energy density function that describes the demagnetisation field, the anhysteretic multi-scale energy-based material model is extended to the hysteretic case. The hysteresis behaviour is included at the domain scale according to the micro-magnetic domain theory while preserving a valid description for the magneto-elastic coupling. The model is verified using existing measurement data for different mechanical stress levels. - Highlights: • A ferromagnetic hysteretic energy-based multi-scale material model is proposed. • The hysteresis is obtained by new proposed hysteresis energy density function. • Avoids tedious parameter identification.

  11. Simulation of electric arc with hysteresis during discharge of a fusion superconducting magnet system

    International Nuclear Information System (INIS)

    Kraus, H.G.; Jones, J.L.

    1986-01-01

    Simulation of an internal voltage induced arc strike and attendant voltage-current hysteresis characteristics in an FED/INTOR scale superconducting magnet and circuit protection system during discharge was performed. To begin, an analytical solution was used to investigate system response for an internally shorted magnet and simplified circuit protection system during magnet discharge. The short produced a current split within the magnet resulting in a transformer like mutual inductance effect. Thus, the coupling coefficient was introduced in the equations to be physically realistic and to prevent degeneration of the associated eigenvalue problem. The effects of varying short resistance, dump resistance, and number of coil turns shorted are presented. This led to simulation of an arc strike, including hysteresis effects, which is then compared to the usual constant resistance used to simulate magnet shorts. Tracking of arc characteristics was made possible through specially developed multiple tripping capabilities recently incorporated into MSCAP (Magnet Systems Circuitry Analysis Program) for safety and instrumentation control simulation

  12. Hysteresis Curve Fitting Optimization of Magnetic Controlled Shape Memory Alloy Actuator

    Directory of Open Access Journals (Sweden)

    Fuquan Tu

    2016-11-01

    Full Text Available As a new actuating material, magnetic controlled shape memory alloys (MSMAs have excellent characteristics such as a large output strain, fast response, and high energy density. These excellent characteristics are very attractive for precision positioning systems. However, the availability of MSMAs in practical precision positioning is poor, caused by weak repeatability under a certain stimulus. This problem results from the error of a large magnetic hysteresis in an external magnetic field. A suitable hysteresis modelling method can reduce the error and improve the accuracy of the MSMA actuator. After analyzing the original hysteresis modelling methods, three kinds of hysteresis modelling methods are proposed: least squares method, back propagation (BP artificial neural network, and BP artificial neural network based on genetic algorithms. Comparing the accuracy and convergence rate of three kinds of hysteresis modelling methods, the results show that the convergence rate of least squares method is the fastest, and the convergence accuracy of BP artificial neural networks based on genetic algorithms is the highest.

  13. Surface impedance tensor in amorphous wires with helical anisotropy: Magnetic hysteresis and asymmetry

    International Nuclear Information System (INIS)

    Makhnovskiy, D. P.; Panina, L. V.; Mapps, D. J.

    2001-01-01

    This article concerns the investigation of the magnetic behavior of the surface impedance tensor cflx var-sigma in CoSiB amorphous wires having a residual torsion stress and a helical anisotropy. The full tensor cflx var-sigma involving three different components is found by measuring the S 21 parameter at a required excitation with a Hewlett-Packard network/spectrum analyzer at MHz frequencies. In general, the impedance plots versus axial magnetic field H ex exhibit a hysteresis related to that for the case of static magnetization. The diagonal components of cflx var-sigma (longitudinal var-sigma zz and circular var-sigma v ar-phi v ar-phi) show a sharp peak in a narrow field interval where the domain walls form and contribute to the ac magnetization dynamics. This peak is not seen for the off-diagonal component var-sigma zv ar-phi (var-sigma v ar-phi z ) since the existence of the domain structure suppresses it. Applying a dc bias current results in a gradual transition to a nonhysteretic asymmetrical behavior with an enhanced sensitivity. The portions of the experimental plots associated with the rotational dynamic process are in qualitative agreement with the theory based on a single-domain model. [copyright] 2001 American Institute of Physics

  14. A combined Preisach–Hyperbolic Tangent model for magnetic hysteresis of Terfenol-D

    Energy Technology Data Exchange (ETDEWEB)

    Talebian, Soheil [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Hojjat, Yousef, E-mail: yhojjat@modares.ac.ir [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Ghodsi, Mojtaba [Department of Mechanical and Industrial Engineering, Sultan Qaboos University, Muscat (Oman); Karafi, Mohammad Reza [Department of Mechanical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Mirzamohammadi, Shahed [Department of Mechanical Engineering, Shahid Rajaee University, Tehran (Iran, Islamic Republic of)

    2015-12-15

    This study presents a new model using the combination of Preisach and Hyperbolic Tangent models, to predict the magnetic hysteresis of Terfenol-D at different frequencies. Initially, a proper experimental setup was fabricated and used to obtain different magnetic hysteresis curves of Terfenol-D; such as major, minor and reversal loops. Then, it was shown that the Hyperbolic Tangent model is precisely capable of modeling the magnetic hysteresis of the Terfenol-D for both rate-independent and rate-dependent cases. Empirical equations were proposed with respect to magnetic field frequency which can calculate the non-dimensional coefficients needed by the model. These empirical equations were validated at new frequencies of 100 Hz and 300 Hz. Finally, the new model was developed through the combination of Preisach and Hyperbolic Tangent models. In the combined model, analytical relations of the Hyperbolic Tangent model for the first order reversal loops determined the weighting function of the Preisach model. This model reduces the required experiments and errors due to numerical differentiations generally needed for characterization of the Preisach function. In addition, it can predict the rate-dependent hysteresis as well as rate-independent hysteresis. - Highlights: • Different hysteresis curves of Terfenol-D are experimentally obtained at 0–200 Hz. • A new model is presented using combination of Preisach and Hyperbolic Tangent models. • The model predicts both rate-independent and rate-dependent hystereses of Terfenol-D. • The analytical model reduces the numerical errors and number of required experiments.

  15. Characterization and modeling of magnetic domain wall dynamics using reconstituted hysteresis loops from Barkhausen noise

    Energy Technology Data Exchange (ETDEWEB)

    Ducharne, B., E-mail: Benjamin.ducharne@insa-lyon.fr; Le, M.Q.; Sebald, G.; Cottinet, P.J.; Guyomar, D.; Hebrard, Y.

    2017-06-15

    Highlights: • Barkhausen noise energy versus excitation field hysteresis cycles MBN{sub energy}(H). • Difference in the dynamics of the induction field B and of the MBN{sub energy}. • Dynamic behavior of MBN{sub energy}(H) cycles is first-order. • Dynamic behavior of B(H) cycles is non-entire order. - Abstract: By means of a post-processing technique, we succeeded in plotting magnetic Barkhausen noise energy hysteresis cycles MBN{sub energy}(H). These cycles were compared to the usual hysteresis cycles, displaying the evolution of the magnetic induction field B versus the magnetic excitation H. The divergence between these comparisons as the excitation frequency was increased gave rise to the conclusion that there was a difference in the dynamics of the induction field and of the MBN{sub energy} related to the domain wall movements. Indeed, for the MBN{sub energy} hysteresis cycle, merely the domain wall movements were involved. On the other hand, for the usual B(H) cycle, two dynamic contributions were observed: domain wall movements and diffusion of the magnetic field excitation. From a simulation point of view, it was demonstrated that over a large frequency bandwidth a correct dynamic behavior of the domain wall movement MBN{sub energy}(H) cycle could be taken into account using first-order derivation whereas fractional orders were required for the B(H) cycles. The present article also gives a detailed description of how to use the developed process to obtain the MBN{sub energy}(H) hysteresis cycle as well as its evolution as the frequency increases. Moreover, this article provides an interesting explanation of the separation of magnetic loss contributions through a magnetic sample: a wall movement contribution varying according to first-order dynamics and a diffusion contribution which in a lump model can be taken into account using fractional order dynamics.

  16. Dynamic magnetic hysteresis behavior and dynamic phase transition in the spin-1 Blume-Capel model

    Energy Technology Data Exchange (ETDEWEB)

    Deviren, Bayram, E-mail: bayram.deviren@nevsehir.edu.tr [Department of Physics, Nevsehir University, 50300 Nevsehir (Turkey); Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

    2012-03-15

    The nature (time variation) of response magnetization m(wt) of the spin-1 Blume-Capel model in the presence of a periodically varying external magnetic field h(wt) is studied by employing the effective-field theory (EFT) with correlations as well as the Glauber-type stochastic dynamics. We determine the time variations of m(wt) and h(wt) for various temperatures, and investigate the dynamic magnetic hysteresis behavior. We also investigate the temperature dependence of the dynamic magnetization, hysteresis loop area and correlation near the transition point in order to characterize the nature (first- or second-order) of the dynamic transitions as well as obtain the dynamic phase transition temperatures. The hysteresis loops are obtained for different reduced temperatures and we find that the areas of the loops are decreasing with the increasing of the reduced temperatures. We also present the dynamic phase diagrams and compare the results of the EFT with the results of the dynamic mean-field approximation. The phase diagrams exhibit many dynamic critical points, such as tricritical ( Bullet ), zero-temperature critical (Z), triple (TP) and multicritical (A) points. According to values of Hamiltonian parameters, besides the paramagnetic (P), ferromagnetic (F) fundamental phases, one coexistence or mixed phase region, (F+P) and the reentrant behavior exist in the system. The results are in good agreement with some experimental and theoretical results. - Highlights: Black-Right-Pointing-Pointer Kinetic spin-1 Blume-Capel model is studied using the effective-field theory. Black-Right-Pointing-Pointer We investigated the dynamic magnetic hysteresis behavior. Black-Right-Pointing-Pointer Dynamic magnetization, hysteresis loop area and correlation are investigated. Black-Right-Pointing-Pointer System exhibits tricritical, zero-temperature, triple and multicritical points. Black-Right-Pointing-Pointer We present the dynamic phase diagrams and compare the results of the EFT

  17. Hysteresis in YHx films observed with in situ measurements

    International Nuclear Information System (INIS)

    Remhof, A.; Kerssemakers, J.W.J.; Molen, S.J. van der; Griessen, R.; Kooij, E.S.

    2002-01-01

    Giant hysteretic effects in the YH x hydrogen switchable mirror system are observed between x=1.9 and x=3 in pressure composition isotherms, optical and electrical properties, and mechanical stress. Polycrystalline Y films are studied by simultaneous in situ measurements of electrical resistivity, optical transmittance and x-ray diffractometry. These experiments are linked to optical microscopy of the samples. During hydrogen loading above x=1.9 the films stay in the metallic fcc phase until the optical transmittance reaches its minimum and the electrical resistance curve exhibits a characteristic feature at x=2.1. Upon further loading the system crosses the miscibility gap in which the fcc phase coexists with the hcp phase before hydrogen saturation is reached in the pure hcp phase. While the fcc phase stays at a concentration of x=2.1 in the coexistence region during loading, it remains at a concentration of x=1.9 during unloading. The hysteretic effects observed in optical transmission and electrical resistivity result from the different properties of the low concentration fcc phase YH 1.9 and the high concentration fcc phase YH 2.1 . They can be explained on the basis of the bulk phase diagram if the different stress states during loading and unloading are taken into account. These results contradict earlier interpretations of the hysteresis in thin film YH x , based on nonsimultaneous measurements of the optical and structural properties on different films

  18. Soft-x-ray magneto-optical Kerr effect and element-specific hysteresis measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kortright, J.B.; Rice, M. [Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    Interest in the utilization of x-ray magneto-optical properties to provide element-specific magnetic information, combined with recent development of tunable linear polarizers for spectroscopic polarization measurement, have led the authors to the study of magneto-optical rotation (MOR) near core levels of magnetic atoms in magnetic multilayer and alloy films. Their initial observation of Faraday rotation (in transmission) demonstrated that for Fe MOR is easily measured and is larger at its L{sub 3} resonance than in the near-visible spectral regions. This work also demonstrated that the spectroscopic behavior of the MOR signal in transmission, resulting from the differential reaction of left- and right-circular components of a linearly polarized beam, is related to the magnetic circular dichroism (MCD), or differential absorption, as expected by a Kramers-Kronig transformation. Thus MCD measurements using circular polarization and MOR measurements using linear polarization can provide complementary, and in some cases equivalent, information. On beamline 6.3.2 the authors have begun to investigate soft x-ray MOR in the reflection geometry, the x-ray magneto-optic Kerr effect (XMOKE). Early measurements have demonstrated the ability to measure element-specific hysteresis loops and large rotations compared to analogous near-visible measurements. The authors are investigating the spectral dependence of the XMOKE signal, and have initiated systematic materials studies of sputter-deposited films of Fe, Fe{sub x}Cr{sub 1{minus}x} alloys, and Fe/Cr multilayers.

  19. Magnetic rotational hysteresis study on spherical 85-160 nm Fe3O4 particles

    Science.gov (United States)

    Schmidbauer, E.

    1988-05-01

    Rotational hysteresis losses Wr were determined as a function of magnetic field H for dispensed spherical Fe3O4 particles of mean grain sizes 85 nm, 127 nm and 162 nm between 78 K and 294 K. The observed Wr-H curves are compared with theoretical curves for single domain particles. The analysed particles reveal centers of high magnetic anisotropy. Such centers can be of importance during the generation of a thermoremanent magnetization, as they may be the origin of enhanced magnetic stability.

  20. Kerr hysteresis loop tracer with alternate driving magnetic field up to 10 kHz

    Science.gov (United States)

    Callegaro, Luca; Fiorini, Carlo; Triggiani, Giacomo; Puppin, Ezio

    1997-07-01

    A magneto-optical Kerr loop tracer for hysteresis loop measurements in thin films with field excitation frequency f0 from 10 mHz to 10 kHz is described. A very high sensitivity is obtained by using an ultrabright light-emitting diode as a low-noise light source and a novel acquisition process. The field is generated with a coil driven by an audio amplifier connected to a free-running oscillator. The conditioned detector output constitutes the magnetization signal (M); the magnetic field (H) is measured with a fast Hall probe. The acquisition electronics are based on a set of sample-and-hold amplifiers which allow the simultaneous sampling of M, H, and dH/dt. Acquisition is driven by a personal computer equipped with a multifunction I/O board. Test results on a 120 nm Fe film on Si substrate are shown. The coercive field of the film increases with frequency and nearly doubles at 10 kHz with respect to dc.

  1. Magnetic hysteresis effects in superconducting coplanar microwave resonators

    Energy Technology Data Exchange (ETDEWEB)

    Bothner, D.; Gaber, T.; Kemmler, M.; Gruenzweig, M.; Ferdinand, B.; Koelle, D.; Kleiner, R. [Universitaet Tuebingen (Germany); Wuensch, S.; Siegel, M. [Karlsruher Institut fuer Technologie (Germany); Mikheenko, P.; Johansen, T.H. [University of Oslo (Norway)

    2013-07-01

    We present experimental data regarding the impact of external magnetic fields on quality factor and resonance frequency of superconducting microwave resonators in a coplanar waveguide geometry. In particular we focus on the influence of magnetic history and show with the assistance of numerical calculations that the found hysteretic behaviour can be well understood with a highly inhomogeneous microwave current density in combination with established field penetration models for type-II superconducting thin films. Furthermore we have used magneto-optical imaging techniques to check the field distribution which we have assumed in our calculations. Finally, we demonstrate that and how the observed hysteretic behaviour can be used to optimize and tune the resonator performance for possible hybrid quantum sytems in magnetic fields.

  2. Magnetization, shape memory and hysteresis behavior of single and polycrystalline FeNiCoTi

    International Nuclear Information System (INIS)

    Sehitoglu, H.; Efstathiou, C.; Maier, H.J.; Chumlyakov, Y.

    2005-01-01

    We report on the shape memory characteristics and magnetic behavior of polycrystalline and single crystalline FeNiCoTi. Predeforming the samples in the martensitic state and biasing of the martensite variants produced anisotropy in the magnetization behavior allowing the 'easy axis' to be identified as the 'a-axis' in the martensitic state. Based on these results, we provide an estimate of the magnetic anisotropy energy as 8.34x10 5 ergs/cm 3 . The results confirm the different magnetization behavior in the martensitic and austenitic states, and the shift in transformation temperatures upon application of a magnetic field. Shape memory strains near 2.5% are demonstrated under constant stress temperature cycling and upon heating at zero stress after deformation. We present a thermodynamics based theory that explains the origin of the hysteresis in this class of alloys emanating from the dissipation of energy due to plastic deformation. We predict the thermal hysteresis (135 K), and the shift in transformation temperature (14 K) with applied magnetic fields in agreement with the experimental results. The possibility of utilizing these classes of alloys as magnetic shape memory alloys is discussed

  3. Random crystal field effect on the magnetic and hysteresis behaviors of a spin-1 cylindrical nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Zaim, N.; Zaim, A., E-mail: ah_zaim@yahoo.fr; Kerouad, M., E-mail: kerouad@fs-umi.ac.ma

    2017-02-15

    In this work, the magnetic behavior of the cylindrical nanowire, consisting of a ferromagnetic core of spin-1 atoms surrounded by a ferromagnetic shell of spin-1 atoms is studied in the presence of a random crystal field interaction. Based on Metropolis algorithm, the Monte Carlo simulation has been used to investigate the effects of the concentration of the random crystal field p, the crystal field D and the shell exchange interaction J{sub s} on the phase diagrams and the hysteresis behavior of the system. Some characteristic behaviors have been found, such as the first and second-order phase transitions joined by tricritical point for appropriate values of the system parameters, triple and isolated critical points can be also found. Depending on the Hamiltonian parameters, single, double and para hysteresis regions are explicitly determined. - Highlights: • Phase diagrams of a ferromagnetic nanowire are examined by the Monte Carlo simulation. • Different types of the phase diagrams are obtained. • The effect of the random crystal field on the hysteresis loops is studied. • Single, double and para hysteresis regions are explicitly determined.

  4. Mechanical characterization of journal superconducting magnetic bearings: stiffness, hysteresis and force relaxation

    International Nuclear Information System (INIS)

    Cristache, Cristian; Valiente-Blanco, Ignacio; Diez-Jimenez, Efren; Alvarez-Valenzuela, Marco Antonio; Perez-Diaz, Jose Luis; Pato, Nelson

    2014-01-01

    Superconducting magnetic bearings (SMBs) can provide stable levitation without direct contact between them and a magnetic source (typically a permanent magnet). In this context, superconducting magnetic levitation provides a new tool for mechanical engineers to design non-contact mechanisms solving the tribological problems associated with contact at very low temperatures. In the last years, different mechanisms have been proposed taking advantage of superconducting magnetic levitation. Flywheels, conveyors or mechanisms for high-precision positioning. In this work the mechanical stiffness of a journal SMBs have been experimentally studied. Both radial and axial stiffness have been considered. The influence of the size and shape of the permanent magnets (PM), the size and shape of the HTS, the polarization and poles configuration of PMs of the journal SMB have been studied experimentally. Additionally, in this work hysteresis behavior and force relaxation are considered because they are essential for mechanical engineer when designing bearings that hold levitating axles.

  5. Magnetic hysteresis of an artificial square ice studied by in-plane Bragg x-ray resonant magnetic scattering

    Directory of Open Access Journals (Sweden)

    J. P. Morgan

    2012-06-01

    Full Text Available We report X-ray resonant magnetic scattering studies of a Permalloy artificial square ice nanomagnet array, focussing on the field-driven evolution of the sum Σ and difference Δ signals of left and right handed circularly polarized synchrotron X-rays at different lateral positions in reciprocal space Qx. We used X-rays tuned to the Fe L3 resonance energy, with the scattering plane aligned along a principal symmetry axis of the array. Details of the specular Δ hysteresis curve are discussed, following the system magnetization from an initial demagnetized state. The periodic structure gives rise to distinct peaks at in-plane reciprocal Bragg positions, as shown by fitting Σ(Qx to a model based on a simple unit cell structure. Diffraction order-dependent hysteresis in Δ is observed, indicative of the reordering of magnetization on the system's two interpenetrating sublattices, which markedly deviates from an ideal Ising picture under strong applied fields.

  6. Hysteresis force loss and damping properties in a practical magnet-superconductor maglev test vehicle

    International Nuclear Information System (INIS)

    Yang Wenjiang; Liu Yu; Wen Zheng; Chen Xiaodong; Duan Yi

    2008-01-01

    In order to investigate the feasible application of a permanent magnet-high-temperature superconductor (PM-HTS) interaction maglev system to a maglev train or a space vehicle launcher, we have constructed a demonstration maglev test vehicle. The force dissipation and damping of the maglev vehicle against external disturbances are studied in a wide range of amplitudes and frequencies by using a sine vibration testing set-up. The dynamic levitation force shows a typical hysteresis behavior, and the force loss is regarded as the hysteresis loss, which is believed to be due to flux motions in superconductors. In this study, we find that the hysteresis loss has weak frequency dependence at small amplitudes and that the dependence increases as the amplitude grows. To analyze the damping properties of the maglev vehicle at different field cooling (FC) conditions, we also employ a transient vibration testing technique. The maglev vehicle shows a very weak damping behavior, and the damping is almost unaffected by the trapped flux of the HTSs in different FC conditions, which is believed to be attributed to the strong pinning in melt-textured HTSs

  7. Hysteresis Analysis and Positioning Control for a Magnetic Shape Memory Actuator

    Science.gov (United States)

    Lin, Jhih-Hong; Chiang, Mao-Hsiung

    2015-01-01

    Magnetic shape memory alloys (MSM alloys), a new kind of smart materials, have become a potential candidate in many engineering fields. MSMs have the advantage of bearing a huge strain, much larger than other materials. In addition, they also have fast response. These characteristics make MSM a good choice in micro engineering. However, MSMs display the obvious hysteresis phenomenon of nonlinear behavior. Thus the difficulty in using the MSM element as a positioning actuator is increased due to the hysteresis. In this paper, the hysteresis phenomenon of the MSM actuator is analyzed, and the closed-loop positioning control is also implemented experimentally. For that, a modified fuzzy sliding mode control (MFSMC) is proposed. The MFSMC and the PID control are used to design the controllers for realizing the positioning control. The experimental results are compared under different experimental conditions, such as different frequency, amplitude, and loading. The experimental results show that the precise positioning control of MFSMC can be achieved satisfactorily. PMID:25853405

  8. Hysteresis modeling of magnetic shape memory alloy actuator based on Krasnosel'skii-Pokrovskii model.

    Science.gov (United States)

    Zhou, Miaolei; Wang, Shoubin; Gao, Wei

    2013-01-01

    As a new type of intelligent material, magnetically shape memory alloy (MSMA) has a good performance in its applications in the actuator manufacturing. Compared with traditional actuators, MSMA actuator has the advantages as fast response and large deformation; however, the hysteresis nonlinearity of the MSMA actuator restricts its further improving of control precision. In this paper, an improved Krasnosel'skii-Pokrovskii (KP) model is used to establish the hysteresis model of MSMA actuator. To identify the weighting parameters of the KP operators, an improved gradient correction algorithm and a variable step-size recursive least square estimation algorithm are proposed in this paper. In order to demonstrate the validity of the proposed modeling approach, simulation experiments are performed, simulations with improved gradient correction algorithm and variable step-size recursive least square estimation algorithm are studied, respectively. Simulation results of both identification algorithms demonstrate that the proposed modeling approach in this paper can establish an effective and accurate hysteresis model for MSMA actuator, and it provides a foundation for improving the control precision of MSMA actuator.

  9. Hysteresis Modeling of Magnetic Shape Memory Alloy Actuator Based on Krasnosel'skii-Pokrovskii Model

    Directory of Open Access Journals (Sweden)

    Miaolei Zhou

    2013-01-01

    Full Text Available As a new type of intelligent material, magnetically shape memory alloy (MSMA has a good performance in its applications in the actuator manufacturing. Compared with traditional actuators, MSMA actuator has the advantages as fast response and large deformation; however, the hysteresis nonlinearity of the MSMA actuator restricts its further improving of control precision. In this paper, an improved Krasnosel'skii-Pokrovskii (KP model is used to establish the hysteresis model of MSMA actuator. To identify the weighting parameters of the KP operators, an improved gradient correction algorithm and a variable step-size recursive least square estimation algorithm are proposed in this paper. In order to demonstrate the validity of the proposed modeling approach, simulation experiments are performed, simulations with improved gradient correction algorithm and variable step-size recursive least square estimation algorithm are studied, respectively. Simulation results of both identification algorithms demonstrate that the proposed modeling approach in this paper can establish an effective and accurate hysteresis model for MSMA actuator, and it provides a foundation for improving the control precision of MSMA actuator.

  10. Freezing-thawing hysteresis phenomena of biological systems by the new method of proton magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Eiichiro; Nagashima, Nobuya (Ajinomoto Co. Inc., Kawasaki, Kanagawa (Japan))

    1982-09-01

    an automatic recording system was developed for unfrozen water content and spin-spin relaxation time measurements as continuous functions of temperature, by using a broad-line pulsed NMR spectrometer and a minicomputer. The advantages of this system are that the exact quantitative measurements can be done by calibrating the nonlinearity of the NMR sensitivity, and that for high sensitivity temperature measurement the thermocouple with special device is directly immersed in a sample. Three types of freezing-thawing hysteresis phenomena, (1) recrystallization of solute (hydroxy-L-proline, D-mannitol) and refreezing of released hydrated water molecules in frozen aqueous solutions, and (2) hysteresis as the characteristic feature of gels (gelatin, alpha sub(sl)-casein), and (3) supercooling of capillary water in water-insoluble materials (zein, yeast RNA, cellulose) were analysed. The usefulness of this system as an analytical instrument of hydration properties of biological materials is emphasized.

  11. Freezing-thawing hysteresis phenomena of biological systems by the new method of proton magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, E.; Nagashima, N.

    1982-01-01

    An automatic recording system was developed for unfrozen water content and spin-spin relaxation time measurements as continuous functions of temperature, by using a broad-line pulsed NMR spectrometer and a mini-computer. The advantages of this system are that the exact quantitative measurements can be done by calibrating the nonlinearity of the NMR sensitivity, and that for high sensitivity temperature measurement the thermocouple with special device is directly immersed in a sample. Three types of freezing-thawing hysteresis phenomena, (1) recrystallization of solute(hydroxy-L-proline, D-mannitol) and refreezing of released hydrated water molecules in frozen aqueous solutions, and (2) hysteresis as the characteristic feature of gels(gelatin, J/sub s1/-casein), and (3) supercooling of capillary water in water-insoluble materials(zein, yeast RNA, cellulose) were analysed. The usefulness of this system as an analytical instrument of hydration properties of biological materials is emphasized.

  12. Freezing-thawing hysteresis phenomena of biological systems by the new method of proton magnetic resonance

    International Nuclear Information System (INIS)

    Suzuki, Eiichiro; Nagashima, Nobuya

    1982-01-01

    an automatic recording system was developed for unfrozen water content and spin-spin relaxation time measurements as continuous functions of temperature, by using a broad-line pulsed NMR spectrometer and a minicomputer. The advantages of this system are that the exact quantitative measurements can be done by calibrating the nonlinearity of the NMR sensitivity, and that for high sensitivity temperature measurement the thermocouple with special device is directly immersed in a sample. Three types of freezing-thawing hysteresis phenomena, (1) recrystallization of solute (hydroxy-L-proline, D-mannitol) and refreezing of released hydrated water molecules in frozen aqueous solutions, and (2) hysteresis as the characteristic feature of gels(gelatin, alpha sub(sl)-casein), and (3) supercooling of capillary water in water-insoluble materials(zein, yeast RNA, cellulose) were analysed. The usefulness of this system as an analytical instrument of hydration properties of biological materials is emphasized. (author)

  13. Thermal and magnetic hysteresis associated with martensitic and magnetic phase transformations in Ni52Mn25In16Co7 Heusler alloy

    Science.gov (United States)

    Madiligama, A. S. B.; Ari-Gur, P.; Ren, Y.; Koledov, V. V.; Dilmieva, E. T.; Kamantsev, A. P.; Mashirov, A. V.; Shavrov, V. G.; Gonzalez-Legarreta, L.; Grande, B. H.

    2017-11-01

    Ni-Mn-In-Co Heusler alloys demonstrate promising magnetocaloric performance for use as refrigerants in magnetic cooling systems with the goal of replacing the lower efficiency, eco-adverse fluid-compression technology. The largest change in entropy occurs when the applied magnetic field causes a merged structural and magnetic transformation and the associated entropy changes of the two transformations works constructively. In this study, magnetic and crystalline phase transformations were each treated separately and the effects of the application of magnetic field on thermal hystereses associated with both structural and magnetic transformations of the Ni52Mn25In16Co7 were studied. From the analysis of synchrotron diffraction data and thermomagnetic measurements, it was revealed that the alloy undergoes both structural (from cubic austenite to a mixture of 7M &5M modulated martensite) and magnetic (ferromagnetic to a low-magnetization phase) phase transformations. Thermal hysteresis is associated with both transformations, and the variation of the thermal hystereses of the magnetic and structural transformations with applied magnetic field is significantly different. Because of the differences between the hystereses loops of the two transformations, they merge only upon heating under a certain magnetic field.

  14. Development of a Compensation Scheme for a Measurement Voltage Transformer Using the Hysteresis Characteristics of a Core

    Directory of Open Access Journals (Sweden)

    Hyewon Lee

    2015-04-01

    Full Text Available This paper describes the design, evaluation, and implementation of a compensation scheme for a measurement voltage transformer (VT using the hysteresis characteristics of the core. The error of a VT is caused by the primary winding voltage and secondary winding voltage. The latter depends on the secondary current, whereas the former depends on the primary current, which is an aggregate of the exciting and secondary currents. The secondary current is obtained directly from the secondary voltage and is used to obtain the voltage across the secondary winding. For the primary current, the exciting current is decomposed into two components: core-loss and magnetizing currents. The magnetizing current is obtained by the flux-magnetizing current curve instead of the hysteresis loop to minimize the required loops for compensation. The core-loss current is obtained by dividing the primary induced voltage by the core-loss resistance. Finally, the estimated voltages across the primary and secondary windings are added to the measured secondary voltage for compensation. The scheme can significantly improve the accuracy of a VT. The results of the performance of compensator are shown in the experimental test. The accuracy of the measurement VT improves from 1.0C class to 0.1C class. The scheme can help to significantly reduce the required core cross section of a measurement VT in an electrical energy system.

  15. Magnetic Biasing of a Ferroelectric Hysteresis Loop in a Multiferroic Orthoferrite

    Science.gov (United States)

    Tokunaga, Y.; Taguchi, Y.; Arima, T.; Tokura, Y.

    2014-01-01

    In a multiferroic orthoferrite Dy0.7Tb0.3FeO3, which shows electric-field-(E-)driven magnetization (M) reversal due to a tight clamping between polarization (P) and M, a gigantic effect of magnetic-field (H) biasing on P-E hysteresis loops is observed in the case of rapid E sweeping. The magnitude of the bias E field can be controlled by varying the magnitude of H, and its sign can be reversed by changing the sign of H or the relative clamping direction between P and M. The origin of this unconventional biasing effect is ascribed to the difference in the Zeeman energy between the +P and -P states coupled with the M states with opposite sign.

  16. Magnetic order, hysteresis, and phase coexistence in magnetoelectric LiCoPO4

    DEFF Research Database (Denmark)

    Fogh, Ellen; Toft-Petersen, Rasmus; Ressouche, Eric

    2017-01-01

    The magnetic phase diagram of magnetoelectric LiCoPO4 is established using neutron diffraction and magnetometry in fields up to 25.9 T applied along the crystallographic b axis. For fields greater than 11.9 T, the magnetic unit cell triples in size with propagation vector Q = (0, 1...... ≈ to (0, 1/2,0) appear for increasing fields in the hysteresis region below the transition field. Traces of this behavior are also observed in the magnetization. A simple model based on a mean-field approach is proposed to explain these additional ordering vectors. In the field interval 20.5-21.0 T....../3,0). A magnetized elliptic cycloid is formed with spins in the (b, c) plane and the major axis oriented along b. Such a structure allows for the magnetoelectric effect with an electric polarization along c induced by magnetic fields applied along b. Intriguingly, additional ordering vectors Q ≈ to (0, 1/4,0) and Q...

  17. Magnetic hysteresis scaling in thulium: Implication of irreversibility-related scaling for soliton wall motion in an Ising system

    International Nuclear Information System (INIS)

    Kobayashi, Satoru

    2013-01-01

    We report low-field magnetic hysteresis scaling in thulium with strong uniaxial anisotropy. A power-law hysteresis scaling with an exponent of 1.13±0.02 is found between hysteresis loss and remanent flux density of minor loops in the low-temperature ferrimagnetic phase. This exponent value is slightly lower than 1.25–1.4 observed previously for ferromagnets and helimagnets. Unlike spiral and/or Bloch walls with a finite transition width, typical for Dy, Tb, and Ho with planar anisotropy, a soliton wall with a sudden phase shift between neighboring domains may dominate in Tm due to its Ising-like character. The observations imply the presence of universality class of hysteresis scaling that depends on the type of magnetic anisotropy. - Highlights: ► We observe magnetic hysteresis scaling in thulium with a power law exponent of 1.13. ► Irreversibility of soliton walls dominates owing to its strong uniaxial anisotropy. ► The exponent is lower than those for Bloch wall and spiral wall. ► The results imply the presence of universality class that depends on the wall type.

  18. Hysteresis in conducting ferromagnets

    International Nuclear Information System (INIS)

    Schneider, Carl S.; Winchell, Stephen D.

    2006-01-01

    Maxwell's magnetic diffusion equation is solved for conducting ferromagnetic cylinders to predict a magnetic wave velocity, a time delay for flux penetration and an eddy current field, one of five fields in the linear unified field model of hysteresis. Measured Faraday voltages for a thin steel toroid are shown to be proportional to magnetic field step amplitude and decrease exponentially in time due to maximum rather than average permeability. Dynamic permeabilities are a field convolution of quasistatic permeability and the delay function from which we derive and observe square root dependence of coercivity on rate of field change

  19. Bias magnetic field and test period dependences of direct and converse magnetoelectric hysteresis of tri-layered magnetoelectric composite

    Science.gov (United States)

    Zhou, Yun; Li, Xiao-Hong; Wang, Jian-Feng; Zhou, Hao-Miao; Cao, Dan; Jiao, Zhi-Wei; Xu, Long; Li, Qi-Hao

    2018-04-01

    The direct and converse magnetoelectric hysteresis behavior for a tri-layered composite has been comparatively investigated and significant similarities have been observed. The results show that both the direct and converse magnetoelectric hysteresis is deeply affected by the bias magnetic field and test period. The test time hysteresis caused by a fast varying bias magnetic field can be reduced by prolonging the test period. The observed coercive field, remanence, and ratio of remanence of the direct and converse magnetoelectric effects with the test period obey an exponential decay law. A hysteretic nonlinear magnetoelectric theoretical model for the symmetrical tri-layered structure has been proposed based on a nonlinear constitutive model and pinning effect. The numerical calculation shows that the theoretical results are in good agreement with the experimental results. These findings not only provide insight into the examination and practical applications of magnetoelectric materials, but also propose a theoretical frame for studying the hysteretic characteristics of the magnetoelectric effect.

  20. Model for hysteresis in magnetostriction

    International Nuclear Information System (INIS)

    Sablik, M.J.; Jiles, D.C.

    1988-01-01

    The domain wall pinning model used previously by the authors to explain magnetic hysteresis and stress effects on magnetic hysteresis is used in conjunction with the Callen and Callen expression for magnetostriction λ to qualitatively explain magnetostriction hysteresis both with respect to magnetic intensity H and flux density B. The Callen and Callen form for the magnetostriction is used because it depends functionally on effective field H/sub e/ rather than M, and this produces hysteresis in λ vs B whereas λ = λ(M) does not. To our knowledge, this is the first time that magnetic hysteresis and magnetostriction hysteresis have been modeled simultaneously

  1. Assessment of Retained Austenite in AISI D2 Tool Steel Using Magnetic Hysteresis and Barkhausen Noise Parameters

    Science.gov (United States)

    Kahrobaee, Saeed; Kashefi, Mehrdad

    2015-03-01

    Inaccurate heat treatment process could result in excessive amount of retained austenite, which degrades the mechanical properties, like strength, wear resistance, and hardness of cold work tool steel parts. Thus, to control the mechanical properties, quantitative measurement of the retained austenite is a critical step in optimizing the heat-treating parameters. X-ray diffraction method is the most frequently used technique for this purpose. This technique is, however, destructive and time consuming. Furthermore, it is not applicable to 100% quality inspection of industrial parts. In the present paper, the influence of austenitizing temperature on the retained austenite content and hardness of AISI D2 tool steel has been studied. Additionally, nondestructive magnetic hysteresis parameters of the samples including coercivity, magnetic saturation, and maximum differential permeability as well as their magnetic Barkhausen noise features (RMS peak voltage and peak position) have been investigated. The results revealed direct relations between magnetic saturation, differential permeability, and MBN peak amplitude with increasing austenitizing temperature due to the retained austenite formation. Besides, both parameters of coercivity and peak position had an inverse correlation with the retained austenite fraction.

  2. Hysteresis in Magnetocaloric Materials

    DEFF Research Database (Denmark)

    von Moos, Lars

    , obtained at the initial low and final high field. However, in first order materials thermal entropy hysteresis loops are obtained through characterization, corresponding to measurements done in an increasing and a decreasing temperature mode. Indirectly determining the MCE through the use of the Maxwell...... order materials, taking the magnetic and thermal history dependence of material properties into account, as well as the heat production due to hysteretic losses. MnFe(P,As) and Gd5Si2Ge2 compounds are modelled and it is found that the Preisach approach is suitable to reproduce material behavior in both......In this thesis the effects of hysteresis on magnetocaloric material properties and their performance in magnetic refrigeration devices are investigated. This is done through an experimental and model study of first order magnetocaloric materials MnFe(P,As) and Gd5Si2Ge2. The experimental...

  3. Reduction of hysteresis for carbon nanotube mobility measurements using pulsed characterization

    International Nuclear Information System (INIS)

    Estrada, David; Dutta, Sumit; Liao, Albert; Pop, Eric

    2010-01-01

    We describe a pulsed measurement technique for suppressing hysteresis for carbon nanotube (CNT) device measurements in air, vacuum, and over a wide temperature range (80-453 K). Varying the gate pulse width and duty cycle probes the relaxation times associated with charge trapping near the CNT, found to be up to the 0.1-10 s range. Longer off times between voltage pulses enable consistent, hysteresis-free measurements of CNT mobility. A tunneling front model for charge trapping and relaxation is also described, suggesting trap depths up to 4-8 nm for CNTs on SiO 2 . Pulsed measurements will also be applicable for other nanoscale devices such as graphene, nanowires, or molecular electronics, and could enable probing trap relaxation times in a variety of material system interfaces.

  4. Influence of applied compressive stress on the hysteresis curves and magnetic domain structure of grain-oriented transverse Fe-3%Si steel

    International Nuclear Information System (INIS)

    Perevertov, O; Schäfer, R

    2012-01-01

    The influence of an applied compressive stress on the hysteresis curve and domain structure in conventional (1 1 0) [0 0 1] Fe-3%Si steel cut transverse to the rolling direction is studied. Quasistatic hysteresis loops under compressive stress up to 75 MPa were measured. The magnetic domains and magnetization processes were observed by longitudinal Kerr microscopy at different levels of stress. It is shown that the bulk hysteresis loop can be described with a good accuracy by the action of an effective field, which is the product of the stress and a function of magnetization. Domain observations have shown that the reasons for the effective field are demagnetizing fields due to the disappearance of supplementary domains along [0 1 0] and [1 0 0] at low fields and different domain systems in different grains at moderate fields. The latter are caused by differences in grain sensitivity to stress depending on the degree of misorientation. A decrease in the effective field above 1 T is connected with a transformation of all grains into the same domain system—the column pattern. (paper)

  5. The nature of transport critical current hysteresis in HTSC: magnetic fields and high pressures. [Y-Ba-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    Svistunov, V M; Yachenko, A.I. d' ; Tarenkov, V Yu [Donetsk Physico-Technical Inst., Ukrainian SSR (USSR)

    1991-12-01

    It was found that pressure has a strong influence on the critical current hysteresis loop of ceramics at H {proportional to} 10 kOe. The phenomenon is attributed to the critical current hysteresis of separate Josephson contacts and is due to the Abrikosov vortex density gradient within granules. The gradient defines both the sign and the value of the pinning current, whereas the sign of Meissner reversible surfaces current component is determined by the external field H direction. As a result the critical current of Josephson contacts defined by the total surface value depends on the magnetic prehistory of a sample. (orig.).

  6. Influence of experimental methods on crossing in magnetic force-gap hysteresis curve of HTS maglev system

    Energy Technology Data Exchange (ETDEWEB)

    Lu Yiyun, E-mail: luyiyun6666@vip.sohu.co [Luoyang Institute of Science and Technology, Luoyang, Henan 471023 (China); Qin Yujie; Dang Qiaohong [Luoyang Institute of Science and Technology, Luoyang, Henan 471023 (China); Wang Jiasu [Applied Superconductivity Laboratory, Southwest Jiaotong University, P.O. Box 152, Chengdu, Sichuan 610031 (China)

    2010-12-01

    The crossing in magnetic levitation force-gap hysteresis curve of melt high-temperature superconductor (HTS) vs. NdFeB permanent magnet (PM) was experimentally studied. One HTS bulk and PM was used in the experiments. Four experimental methods were employed combining of high/low speed of movement of PM with/without heat insulation materials (HIM) enclosed respectively. Experimental results show that crossing of the levitation force-gap curve is related to experimental methods. A crossing occurs in the magnetic force-gap curve while the PM moves approaching to and departing from the sample with high or low speed of movement without HIM enclosed. When the PM is enclosed with HIM during the measurement procedures, there is no crossing in the force-gap curve no matter high speed or low speed of movement of the PM. It was found experimentally that, with the increase of the moving speed of the PM, the maximum magnitude of levitation force of the HTS increases also. The results are interpreted based on Maxwell theories and flux flow-creep models of HTS.

  7. Influence of experimental methods on crossing in magnetic force-gap hysteresis curve of HTS maglev system

    International Nuclear Information System (INIS)

    Lu Yiyun; Qin Yujie; Dang Qiaohong; Wang Jiasu

    2010-01-01

    The crossing in magnetic levitation force-gap hysteresis curve of melt high-temperature superconductor (HTS) vs. NdFeB permanent magnet (PM) was experimentally studied. One HTS bulk and PM was used in the experiments. Four experimental methods were employed combining of high/low speed of movement of PM with/without heat insulation materials (HIM) enclosed respectively. Experimental results show that crossing of the levitation force-gap curve is related to experimental methods. A crossing occurs in the magnetic force-gap curve while the PM moves approaching to and departing from the sample with high or low speed of movement without HIM enclosed. When the PM is enclosed with HIM during the measurement procedures, there is no crossing in the force-gap curve no matter high speed or low speed of movement of the PM. It was found experimentally that, with the increase of the moving speed of the PM, the maximum magnitude of levitation force of the HTS increases also. The results are interpreted based on Maxwell theories and flux flow-creep models of HTS.

  8. Resistivity, hysteresis, and magnetization of 9% Cr stainless steel as a function of temperature and its electromagnetic shielding effects in cylindrical structures

    International Nuclear Information System (INIS)

    Praeg, W.F.

    1979-01-01

    Ferromagnetic stainless steels may offer significantly greater wall life-times for first wall/blanket and vacuum vessel structures than commonly used non-magnetic stainless steels. One steel under consideration has the following composition, in wt %, Fe(86.24), Cr(9), Mo(2), Mn(1), Si(0.75), Nb(0.50), V(0.30), C(0.15), P(0.3), S(0.30). There appears to be no literature on the electromagnetic properties of this material. Therefore, the resistivity, the hysteresis loops, and magnetization were measured as a function of temperature up to the Curie point

  9. Hysteresis in the tearing mode locking/unlocking due to resonant magnetic perturbations in EXTRAP T2R

    Science.gov (United States)

    Fridström, R.; Frassinetti, L.; Brunsell, P. R.

    2015-10-01

    The physical mechanisms behind the hysteresis in the tearing mode locking and unlocking to a resonant magnetic perturbation (RMP) are experimentally studied in EXTRAP T2R reversed-field pinch. The experiments show that the electromagnetic and the viscous torque increase with increasing perturbation amplitude until the mode locks to the wall. At the wall-locking, the plasma velocity reduction profile is peaked at the radius where the RMP is resonant. Thereafter, the viscous torque drops due to the relaxation of the velocity in the central plasma. This is the main reason for the hysteresis in the RMP locking and unlocking amplitude. The increased amplitude of the locked tearing mode produces further deepening of the hysteresis. Both experimental results are in qualitative agreement with the model in Fitzpatrick et al (2001 Phys. Plasmas 8 4489)

  10. Hysteresis of ferrogels magnetostriction

    Energy Technology Data Exchange (ETDEWEB)

    Zubarev, Andrey; Chirikov, Dmitry [Urals Federal University, 620000 Ekaterinburg (Russian Federation); Stepanov, Gennady [State Scientific Research Institute of Chemistry and Technology of Organoelement Compounds, 105118 Moscow (Russian Federation); Borin, Dmitry [Technische Universität Dresden, Magnetofluiddynamics, Measuring and Automation Technology, 01062 Dresden (Germany)

    2017-06-01

    We propose a theoretical model of magnetostriction hysteresis in soft magnetic gels filled by micronsized magnetizable particles. The hysteresis is explained by unification of the particles into linear chain-like aggregates while the field increasing and rupture of the chains when the field is decreased. - Highlights: • A theoretical model of magnetostriction hysteresis in magnetic gels is proposed. • Hysteresis is explained by the unification of the particles into chains and the rupture of this chains. • In the order of magnitude theoretical results are in agreement with the experimental one.

  11. Magnetic hysteresis properties of melt-spun Nd-Fe-B alloys prepared by centrifugal method

    International Nuclear Information System (INIS)

    Andreev, S.V.; Kudrevatykh, N.V.; Pushkarsky, V.I.; Markin, P.E.; Zaikov, N.K.; Tarasov, E.N.

    1998-01-01

    Magnetic hysteresis properties and microstructure peculiarities of melt spun Nd-Fe-B alloys (ribbons) prepared by melt quenching onto the internal surface of an iron spinning wheel at tangential speeds in the range 5-20 m/s are reported. The alloy composition was Nd-36% wt, B-1.2% wt. and Fe-remainder. It was found that the coercivity of ribbons does not practically depend on the wheel speed in applied range (18 kOe at 5 m/s and 22 kOe at 20 m/s), whereas the grain size of the basic phase (2-14-1) ste[ily decreases when the speed rises, starting from 2-3 μm for 5 m/s alloy down to the 200-300 nm for 20 m/s alloy. All ribbons have normal convex demagnetization curves, even those prepared at low wheel speeds (without peculiar step near H∝0, which usually exists on such curves for tr[itionally prepared underquenched melt-spun Nd-Fe-B alloys). Grinding the ribbon in a vibration mill causes the coercivity drop to 7 kOe after 120 min of treatment. However, this operation increases the powder alignment ability and, as a result, the energy product for a fully dense magnet from anisotropic powder prepared from some ribbons rises to 20-23 MGOe. (orig.)

  12. Influence of the spin reorientation transition on the hysteresis characteristics of Nd-Fe-B film and bulk magnets

    International Nuclear Information System (INIS)

    Lileev, A.S.; Parilov, A.A.; Reissner, M.; Steiner, W.

    2004-01-01

    A comparison was made of the hysteresis characteristics of hard magnetic films with those of bulk samples based on Nd 2 Fe 14 B in the temperature range between 4.2 and 293 K. In both types of specimens characteristic 'dips' appear below 135 K in the demagnetisation curves which are caused by both the spin reorientation from easy axis to easy cone and the deviation from a perfect texture of the sample

  13. Large roomtemperature magnetocaloric effect with negligible magnetic hysteresis losses in Mn1-xVxCoGe alloys

    International Nuclear Information System (INIS)

    Ma, S.C.; Zheng, Y.X.; Xuan, H.C.; Shen, L.J.; Cao, Q.Q.; Wang, D.H.; Zhong, Z.C.; Du, Y.W.

    2012-01-01

    The magnetic and magnetocaloric properties have been investigated in a series of Mn 1-x V x CoGe (x=0.01, 0.02, 0.03, and 0.05) alloys. The substitution of V for Mn reduces the structural transformation temperature of MnCoGe alloy effectively and results in a second-order magnetic transition in Mn 0.95 V 0.05 CoGe alloys. Large room temperature magnetocaloric effect and almost zero magnetic hysteresis losses are simultaneously achieved in the alloys with x=0.01, 0.02, and 0.03. The reasons for the negligible magnetic hysteresis losses and the potential application for the roomtemperature magnetic refrigeration are discussed. - Highlights: → V-substitution for Mn reduces the structural transformation temperature of MnCoGe. → FM-PM transition presents the second-order nature in Mn0.95V0.05CoGe. → The first-order FM-PM transitions are observed for alloys with x=0.01, 0.02, and 0.03. → Large room temperature MCEs are achieved in these alloys. → Negligible magnetic HL is achieved for these alloys simultaneously.

  14. Magnetic Hysteresis of Deep-Sea Sediments in Korea Deep Ocean Study(KODOS) Area, NE Pacific

    Science.gov (United States)

    Kim, K.; Park, C.; Yoo, C.

    2001-12-01

    The KODOS area within the Clarion-Clipperton fracture zone (C-C zone) is surrounded by the Hawaiian and Line Island Ridges to the west and the central American continent to the east. Topography of the seafloor consists of flat-topped abyssal hills and adjacent abyssal troughs, both of which run parallel in N-S direction. Sediments from the study area consist mainly of biogenic sediments. Latitudinal zonation of sedimentary facies was caused by the accumulation of biogenic materials associated with the equatorial current system and movement of the Pacific plate toward the north or northwest. The KODOS area belongs to the latitudinal transition zone having depositional characteristics between non-fossiliferous pelagic clay-dominated zone and calcareous sediment-dominated zone. The box core sediments of the KODOS area are analyzed in an attempt to obtain magnetic hysteresis information and to elucidate the relationship between hysteresis property and lithological facies. Variations in magnetic hysteresis parameters with unit layers reflect the magnetic grain-size and concentrations within the sediments. The ratios of remanant coercivity/coercive force (Hcr/Hc) and saturation remnance/saturation magnetization (Mrs/Ms) indicate that coarse magnetic grains are mainly distributed in dark brown sediments (lower part of the sediment core samples) reflecting high Hcr/Hc and low Mrs/Ms ratios. These results are mainly caused by dissolution differences with core depth. From the plotting of the ratios of hyteresis parameters, it is indicated that magnetic minerals in cubic samples are in pseudo-single domain (PSD) state.

  15. Influence of magnetostriction on hysteresis loss of electrical steel sheet

    Energy Technology Data Exchange (ETDEWEB)

    Tada, Hirotoshi, E-mail: tada.547.hirotoshi@jp.nssmc.com [Steel Research Laboratories, Nippon Steel and Sumitomo Metal Corporation, 1-8 Fuso-cho, Amagasaki, Hyogo 660-0891 (Japan); Fujimura, Hiroshi; Yashiki, Hiroyoshi [Steel Research Laboratories, Nippon Steel and Sumitomo Metal Corporation, 1-8 Fuso-cho, Amagasaki, Hyogo 660-0891 (Japan)

    2013-01-15

    To reveal influence of magnetostriction on hysteresis loss of electrical steel sheet, hysteresis loss and magnetostriction of non-oriented electrical steel sheets (NOs) with various Si and Al content and grain size and grain oriented electrical steel sheet (GO) were measured under compressive or tensile stress. Here, Si and Al content and stress were focused on as the way to change magnetostriction. Stress direction and magnetizing direction were parallel to the rolling direction. Following three main results were obtained. The first is hysteresis loss of NO with same grain size which increased with magnetostriction independently of Si and Al content and stress. The second is hysteresis loss of NO was larger than that of GO under same magnetostriction. The third is hysteresis loss of NO at magnetostriction of zero was inversely proportional to grain size. Even if the grain size of NO increased to be similar size of GO without changing texture, the hysteresis loss of NO at magnetostriction of zero would be larger than that of GO because of the difference in texture. - Highlights: Black-Right-Pointing-Pointer Hysteresis loss and magnetostriction of NO and GO were measured under stress. Black-Right-Pointing-Pointer Hysteresis loss of NO was proportional to magnetostriction. Black-Right-Pointing-Pointer Hysteresis loss of GO was proportional to magnetostriction. Black-Right-Pointing-Pointer Hysteresis loss of NO was larger than that of GO under samemagnetostriction. Black-Right-Pointing-Pointer Hysteresis loss was separated into 4 components.

  16. Application of magnetomechanical hysteresis modeling of magnetic techniques for monitoring neutron embrittlement and biaxial stress

    International Nuclear Information System (INIS)

    Sablik, M.J.; Kwun, H.; Burkhardt, G.L.

    1993-01-01

    Research was done on the biaxial stress problem accomplished in the first half of the second year. All of the work done was preparatory to magnetic measurements. Issues addressed were: construction of a model for extracting changes in the magnetic properties of a specimen from the readings of an indirect sensor; initial development of a model for how biaxial stress alters the intrinsic magnetic properties of thespecimen; use of finite element stress analysis modeling to determine a detailed shape for the cruciform biaxial stress specimen; and construction of the biaxial stress loading apparatus

  17. Analysis of magnetic field and hysteresis of reed switches for control rod position indicator of SMART CEDM

    International Nuclear Information System (INIS)

    Yoo, J. W.; Kim, J. H.; Heo, H.; Kim, J. I.; Jang, M. H.

    2002-01-01

    The reliability and accuracy of the information on control rod position are very important to the reactor safety and the design of the core protection system. A survey on the RSPT(Reed Switch Position Transmitter) type control rod position indication system and its actual implementation in the exiting nuclear power plants in Korea was performed first. The control rod position indicator having the high performance for SMART was developed on the basis of RSPT technology identified through the survey. The hysteresis of reed switches is one of the important factors in a repeat accuracy of control rod position indication. In this study, the hysteresis of reed switches is introduced and the design method using the magnetic analysis of reed switches in presented

  18. Nondestructive characterization of recovery and recrystallization in cold rolled low carbon steel by magnetic hysteresis loops

    International Nuclear Information System (INIS)

    Martinez-de-Guerenu, A.; Gurruchaga, K.; Arizti, F.

    2007-01-01

    How structure sensitive parameters derived from hysteresis loops can provide nondestructive information about the evolution of the microstructure of cold rolled low carbon steel as a result of recovery and recrystallization processes during the annealing is shown. The coercive field, remanent induction and hysteresis losses can be used to monitor the decrease in the dislocation density during recovery. These parameters are also influenced by the average grain refinement that takes place during recrystallization, which compensates the variation produced by the annihilation of dislocations during recrystallization. The maximum of the induction and of the relative differential permeability are shown to be very sensitive to the onset and to the monitoring of the recrystallization, respectively. The correlations between coercive field and remanent induction and hysteresis losses can also be used to distinguish between recovery and recrystallization

  19. Effect of applied tensile stress on the hysteresis curve and magnetic domain structure of grain-oriented transverse Fe-3%Si steel

    Czech Academy of Sciences Publication Activity Database

    Perevertov, Oleksiy; Thielsch, J.; Schäfer, R.

    2015-01-01

    Roč. 385, Jul (2015), 358-367 ISSN 0304-8853 R&D Projects: GA ČR GA13-18993S Institutional support: RVO:68378271 Keywords : magnetic domains * magnetization process * magnetoelasticity * hysteresis loops * tension * Kerr microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.357, year: 2015

  20. Magnetic anisotropies and rotational hysteresis in Ni81Fe19/Fe50Mn50 films: A study by torque magnetometry and anisotropic magnetoresistance

    Science.gov (United States)

    da Silva, O. E.; de Siqueira, J. V.; Kern, P. R.; Garcia, W. J. S.; Beck, F.; Rigue, J. N.; Carara, M.

    2018-04-01

    Exchange bias properties of NiFe/FeMn thin films have been investigated through X-ray diffraction, hysteresis loops, angular measurements of anisotropic magnetoresistance (AMR) and magnetic torque. As first predicted by Meiklejohn and Bean we found a decrease on the bias field as the NiFe layer thickness increases. However such reduction is not as strong as expected and it was attributed to the increase on the number of uncompensed antiferromagnetic spins resulting from the increase on the number of FeMn grains at the interface as the thickness of the NiFe layer is increased. The angular evolution of AMR and the magnetic torque were calculated and compared to the experimental ones using the minimization of the free magnetic energy and finding the magnetization equilibrium angle. The free energy, for each grain of the polycrystalline sample, is composed by the following terms: Zeeman, uniaxial, unidirectional and the rotatable energies. While from the AMR curves we obtain stable anisotropy fields independently on the measuring fields, from the torque curves we obtain increasing values of the uniaxial and rotatable fields, as the measuring field is increased. These results were attributed to the physical origin and sensitivity of the two different techniques. Magnetoresistance is mainly sensitive to the inner portion of the ferromagnetic layer, and the torque brings out information of the whole ferromagnetic layer including the interface of the layers. In this way, we believe that the increase in the uniaxial and rotatable values were due to an increase on the volume of the ferromagnetic layer, near the interfaces, which is made to rotate with the measuring field. Studying the rotational hysteresis by both techniques allows to separately obtain the contributions coming from the inner portion of ferromagnetic layer and from the interface.

  1. Magnetization hysteresis and history effects in conventional and high temperature superconductors

    International Nuclear Information System (INIS)

    Chaddah, P.

    1990-01-01

    The magnetization in hard superconductors is irreversible and history-dependent, and cannot be a priori compared with the equilibrium magnetization. These features have gained prominence in the high T c superconductors (HTSC) where the short coherence length presumably leads to intrinsic pinning. Various experimental features, first noticed in the HTSC, are explained by an extension of Bean's macroscopic model to include temperature variations and the field dependence of J c . This paper discusses recent measurements of history effects in niobium and show their similarities with other published data on HTSC. The authors also present our calculations of magnetization behaviour in hard superconductors of sample-shapes having a non-zero demagnetization factor

  2. Influence of applied compressive stress on the hysteresis curves and magnetic domain structure of grain-oriented transverse Fe–3%Si steel

    Czech Academy of Sciences Publication Activity Database

    Perevertov, Oleksiy; Schäfer, R.

    2012-01-01

    Roč. 45, č. 13 (2012), "135001-1"-"135001-11" ISSN 0022-3727 Grant - others:GA AV ČR(CZ) M100100906 Institutional research plan: CEZ:AV0Z10100520 Keywords : hysteresis curve * magnetic domains * compressive stress * goss steel * effective field Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.528, year: 2012

  3. Designing Hysteresis with Dipolar Chains

    Science.gov (United States)

    Concha, Andrés; Aguayo, David; Mellado, Paula

    2018-04-01

    Materials that have hysteretic response to an external field are essential in modern information storage and processing technologies. A myriad of magnetization curves of several natural and artificial materials have previously been measured and each has found a particular mechanism that accounts for it. However, a phenomenological model that captures all the hysteresis loops and at the same time provides a simple way to design the magnetic response of a material while remaining minimal is missing. Here, we propose and experimentally demonstrate an elementary method to engineer hysteresis loops in metamaterials built out of dipolar chains. We show that by tuning the interactions of the system and its geometry we can shape the hysteresis loop which allows for the design of the softness of a magnetic material at will. Additionally, this mechanism allows for the control of the number of loops aimed to realize multiple-valued logic technologies. Our findings pave the way for the rational design of hysteretical responses in a variety of physical systems such as dipolar cold atoms, ferroelectrics, or artificial magnetic lattices, among others.

  4. Influence of applied tensile stress on the hysteresis curve and magnetic domain structure of grain-oriented Fe–3%Si steel

    Czech Academy of Sciences Publication Activity Database

    Perevertov, Oleksiy; Schäfer, R.

    2014-01-01

    Roč. 47, č. 18 (2014), s. 1-10 ISSN 0022-3727 R&D Projects: GA ČR(CZ) GAP107/11/0391 Grant - others:AVČR(CZ) M100100906 Institutional support: RVO:68378271 Keywords : magnetic domains * magnetization process * magnetoelasticity * hysteresis loops * tension * silicon steel * Kerr microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.721, year: 2014

  5. Magnetoacoustic measurements on steel samples at low magnetizing frequencies

    Czech Academy of Sciences Publication Activity Database

    Perevertov, Oleksiy; Stupakov, Alexandr

    2015-01-01

    Roč. 66, č. 7 (2015), s. 58-61 ISSN 1335-3632 R&D Projects: GA ČR GA13-18993S; GA ČR GB14-36566G Institutional support: RVO:68378271 Keywords : magneto-acoustic emission * surface magnetic field * steel * magnetic hysteresis Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 0.407, year: 2015

  6. Quantum mechanics and the second law of thermodynamics: an insight gleaned from magnetic hysteresis in the first order phase transition of an isolated mesoscopic-size type I superconductor

    International Nuclear Information System (INIS)

    Keefe, Peter D

    2012-01-01

    J Bardeen proposed that the adiabatic phase transition of mesoscopic-size type I superconductors must be accompanied by magnetic hysteresis in the critical magnetic field of sufficient magnitude to satisfy the second law of thermodynamics, herein referred to as ‘Bardeen Hysteresis’. Bardeen Hysteresis remains speculative in that it has not been reported in the literature. This paper investigates Bardeen Hysteresis as a possible accompaniment to the adiabatic phase transition of isolated mesoscopic-size type I superconductors and its implications with respect to the second law of thermodynamics. A causal mechanism for Bardeen Hysteresis is discussed which contrasts with the long accepted causal mechanism of magnetic hysteresis, as first summarized by Pippard, herein referred to as ‘Pippard Hysteresis’. The paper offers guidance for an experimental verification and comments on how the existence of Bardeen Hysteresis has relation to a quantum mechanical basis for the second law of thermodynamics.

  7. Quantum mechanics and the second law of thermodynamics: an insight gleaned from magnetic hysteresis in the first order phase transition of an isolated mesoscopic-size type I superconductor

    Science.gov (United States)

    Keefe, Peter D.

    2012-11-01

    J Bardeen proposed that the adiabatic phase transition of mesoscopic-size type I superconductors must be accompanied by magnetic hysteresis in the critical magnetic field of sufficient magnitude to satisfy the second law of thermodynamics, herein referred to as ‘Bardeen Hysteresis’. Bardeen Hysteresis remains speculative in that it has not been reported in the literature. This paper investigates Bardeen Hysteresis as a possible accompaniment to the adiabatic phase transition of isolated mesoscopic-size type I superconductors and its implications with respect to the second law of thermodynamics. A causal mechanism for Bardeen Hysteresis is discussed which contrasts with the long accepted causal mechanism of magnetic hysteresis, as first summarized by Pippard, herein referred to as ‘Pippard Hysteresis’. The paper offers guidance for an experimental verification and comments on how the existence of Bardeen Hysteresis has relation to a quantum mechanical basis for the second law of thermodynamics.

  8. Magnetic Measurement and Magnet Tutorial, Part 3

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, Jack

    2003-07-15

    Magnetic measurements, like magnet design, is a broad subject. It is the intention of this lecture to cover only a small part of the field, regarding the characterization of the line integral field quality of multipole magnets (dipoles, quadrupoles and sextupoles) using compensated rotating coils. Other areas which are not covered are magnet mapping, AC measurements and sweeping wire measurements.

  9. Rate-dependent extensions of the parametric magneto-dynamic model with magnetic hysteresis

    Directory of Open Access Journals (Sweden)

    S. Steentjes

    2017-05-01

    Full Text Available This paper extends the parametric magneto-dynamic model of soft magnetic steel sheets to account for the phase shift between local magnetic flux density and magnetic field strength. This phase shift originates from the damped motion of domain walls and is strongly dependent on the microstructure of the material. In this regard, two different approaches to include the rate-dependent effects are investigated: a purely phenomenological, mathematical approach and a physical-based one.

  10. Efficient Use of Preisach Hysteresis Model in Computer Aided Design

    Directory of Open Access Journals (Sweden)

    IONITA, V.

    2013-05-01

    Full Text Available The paper presents a practical detailed analysis regarding the use of the classical Preisach hysteresis model, covering all the steps, from measuring the necessary data for the model identification to the implementation in a software code for Computer Aided Design (CAD in Electrical Engineering. An efficient numerical method is proposed and the hysteresis modeling accuracy is tested on magnetic recording materials. The procedure includes the correction of the experimental data, which are used for the hysteresis model identification, taking into account the demagnetizing effect for the sample that is measured in an open-circuit device (a vibrating sample magnetometer.

  11. Nanocrystalline structure formation and magnetic hysteresis properties of Y-Fe-Co-B alloys

    Czech Academy of Sciences Publication Activity Database

    Tereshina, I. S.; Tereshina, Evgeniya; Burkhanov, G.S.; Dobatkin, S.V.

    2010-01-01

    Roč. 25, č. 1 (2010), s. 82-87 ISSN 1606-5131. [International Symposium on Bulk Nanostructures Materials /2./. Ufa, 22.09.2009-26.09.2009] Institutional research plan: CEZ:AV0Z10100520 Keywords : R-Fe-B magnets * melt spinning * structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.649, year: 2010

  12. Dynamic hysteresis behaviors for the two-dimensional mixed spin (2, 5/2) ferrimagnetic Ising model in an oscillating magnetic field

    Science.gov (United States)

    Ertaş, Mehmet

    2015-09-01

    Keskin and Ertaş (2009) presented a study of the magnetic properties of a mixed spin (2, 5/2) ferrimagnetic Ising model within an oscillating magnetic field. They employed dynamic mean-field calculations to find the dynamic phase transition temperatures, the dynamic compensation points of the model and to present the dynamic phase diagrams. In this work, we extend the study and investigate the dynamic hysteresis behaviors for the two-dimensional (2D) mixed spin (2, 5/2) ferrimagnetic Ising model on a hexagonal lattice in an oscillating magnetic field within the framework of dynamic mean-field calculations. The dynamic hysteresis curves are obtained for both the ferromagnetic and antiferromagnetic interactions and the effects of the Hamiltonian parameters on the dynamic hysteresis behaviors are discussed in detail. The thermal behaviors of the coercivity and remanent magnetizations are also investigated. The results are compared with some theoretical and experimental works and a qualitatively good agreement is found. Finally, the dynamic phase diagrams depending on the frequency of an oscillating magnetic field in the plane of the reduced temperature versus magnetic field amplitude is examined and it is found that the dynamic phase diagrams display richer dynamic critical behavior for higher values of frequency than for lower values.

  13. Magnetic Measurement of the 10 kW, IR FEL Dipole Magnets

    International Nuclear Information System (INIS)

    Tommy Hiatt; Kenneth Baggett; J. Beck; George Biallas; David Douglas; Kevin Sullivan; C. Tennant

    2003-01-01

    Magnetic measurements have been performed on several families of dipoles for the 10 kW IR-FEL presently under construction at the Thomas Jefferson National Accelerator Facility. The requirements for these magnets include varying field strengths, large horizontal apertures and parts in 10,000 field homogeneity as well as setability of core and integrated field. Measurements were made to quantify the magnets according to these requirements and to determine the hysteresis protocol, ramp rate dependence, and field clamp settings that are used. This paper will describe the results of these measurements and the procedures used to accomplish them

  14. 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.

  15. Measurements of quadrupole magnets

    International Nuclear Information System (INIS)

    Conradie, J.L.; Fourie, D.T.; Cornell, J.C.; Lloyd, G.C.W.

    1987-01-01

    Measurements carried out on quadrupole magnets using a long asymmetric rotating coil are described. Although the method itself is fairly well-known, the introduction of microprocessors has made this once-tedious technique into a useful and simple method of evaluating quadrupole magnets. The rotating-coil device and a variety of coil sizes are now commercially available. The coil contains a large number of extremely fine wires, embedded in a carefully balanced fibre-glass rotor, resulting in a reasonable induced voltage when the coil is rotated. A digital harmonic analyser is then used to obtain the integrated multipole content of the waveform, while the coil is rotating. By integrating over time, one can average out random noise and increase the reliability and repeatability of the measurements. Because the harmonic analysis is done in real time, the method is quick, easy and accurate, and has been extended to locate the precise magnetic centre of the quadrupole magnet by adjusting its position relative to the coil axis so as to minimize the dipole content of the output waveform. Results of these measurements are compared with those obtained with an optical method using a suspension of magnetite. The observed light pattern is explained analytically. (author)

  16. Hysteresis losses in MgB{sub 2} superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, N., E-mail: niklas.magnusson@sintef.no [SINTEF Energy Research, NO-7465 Trondheim (Norway); Abrahamsen, A.B. [DTU Wind Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Liu, D. [Electrical Power Processing Group, TU Delft, Mekelweg 4, NL-2628 CD Delft (Netherlands); Runde, M. [SINTEF Energy Research, NO-7465 Trondheim (Norway); Polinder, H. [Electrical Power Processing Group, TU Delft, Mekelweg 4, NL-2628 CD Delft (Netherlands)

    2014-11-15

    Highlights: • A method for calculating hysteresis losses in the low AC – high DC magnetic field and transport current range has been shown. • The method can be used in the design of wind turbine generators for calculating the losses in the generator DC rotor. • First estimates indicate tolerable current ripple in the 0.1% range for a 4 T DC MgB{sub 2} generator rotor coil. - Abstract: MgB{sub 2} superconductors are considered for generator field coils for direct drive wind turbine generators. In such coils, the losses generated by AC magnetic fields may generate excessive local heating and add to the thermal load, which must be removed by the cooling system. These losses must be evaluated in the design of the generator to ensure a sufficient overall efficiency. A major loss component is the hysteresis losses in the superconductor itself. In the high DC – low AC current and magnetic field region experimental results still lack for MgB{sub 2} conductors. In this article we reason towards a simplified theoretical treatment of the hysteresis losses based on available models in the literature with the aim of setting the basis for estimation of the allowable magnetic fields and current ripples in superconducting generator coils intended for large wind turbine direct drive generators. The resulting equations use the DC in-field critical current, the geometry of the superconductor and the magnitude of the AC magnetic field component as parameters. This simplified approach can be valuable in the design of MgB{sub 2} DC coils in the 1–4 T range with low AC magnetic field and current ripples.

  17. Hysteresis losses in MgB2 superconductors exposed to combinations of low AC and high DC magnetic fields and transport currents

    DEFF Research Database (Denmark)

    Magnusson, N.; Abrahamsen, Asger Bech; Liu, Dawei

    2014-01-01

    MgB2 superconductors are considered for generator field coils for direct drive wind turbine generators. In such coils, the losses generated by AC magnetic fields may generate excessive local heating and add to the thermal load, which must be removed by the cooling system. These losses must...... a simplified theoretical treatment of the hysteresis losses based on available models in the literature with the aim of setting the basis for estimation of the allowable magnetic fields and current ripples in superconducting generator coils intended for large wind turbine direct drive generators. The resulting...

  18. Simulation of field effects on the mechanical hysteresis of Terfenol rods and magnetic shape memory materials using vector Preisach-type models

    International Nuclear Information System (INIS)

    Adly, A.A.; Davino, D.; Visone, C.

    2006-01-01

    Materials exhibiting gigantic magnetostriction and magnetic shape memory are currently being widely used in various applications. Recently, an approach based on simulating 1-D magnetostriction using 2-D anisotropic Preisach-type models has been introduced. The purpose of this paper is to present a detailed formulation and quantitative assessment for the simulation of field effects on the mechanical hysteresis of Terfenol rods and magnetic shape memory materials using this recently proposed model. Details of the model formulation, identification procedure and experimental testing are given in the paper

  19. Measurement of contact-angle hysteresis for droplets on nanopillared surface and in the Cassie and Wenzel states: a molecular dynamics simulation study.

    Science.gov (United States)

    Koishi, Takahiro; Yasuoka, Kenji; Fujikawa, Shigenori; Zeng, Xiao Cheng

    2011-09-27

    We perform large-scale molecular dynamics simulations to measure the contact-angle hysteresis for a nanodroplet of water placed on a nanopillared surface. The water droplet can be in either the Cassie state (droplet being on top of the nanopillared surface) or the Wenzel state (droplet being in contact with the bottom of nanopillar grooves). To measure the contact-angle hysteresis in a quantitative fashion, the molecular dynamics simulation is designed such that the number of water molecules in the droplets can be systematically varied, but the number of base nanopillars that are in direct contact with the droplets is fixed. We find that the contact-angle hysteresis for the droplet in the Cassie state is weaker than that in the Wenzel state. This conclusion is consistent with the experimental observation. We also test a different definition of the contact-angle hysteresis, which can be extended to estimate hysteresis between the Cassie and Wenzel state. The idea is motivated from the appearance of the hysteresis loop typically seen in computer simulation of the first-order phase transition, which stems from the metastability of a system in different thermodynamic states. Since the initial shape of the droplet can be controlled arbitrarily in the computer simulation, the number of base nanopillars that are in contact with the droplet can be controlled as well. We show that the measured contact-angle hysteresis according to the second definition is indeed very sensitive to the initial shape of the droplet. Nevertheless, the contact-angle hystereses measured based on the conventional and new definition seem converging in the large droplet limit. © 2011 American Chemical Society

  20. Mathematical modelling of frequency-dependent hysteresis and energy loss of FeBSiC amorphous alloy

    International Nuclear Information System (INIS)

    Koprivica, Branko; Milovanovic, Alenka; Mitrovic, Nebojsa

    2017-01-01

    The aim of this paper is to present a novel mathematical model of frequency-dependent magnetic hysteresis. The major hysteresis loop in this model is represented by the ascending and descending curve over an arctangent function. The parameters of the hysteresis model have been calculated from a measured hysteresis loop of the FeBSiC amorphous alloy sample. A number of measurements have been performed with this sample at different frequencies of the sinusoidal excitation magnetic field. A variation of the coercive magnetic field with the frequency has been observed and used in the modelling of frequency-dependent hysteresis with the proposed model. A comparison between measured and modelled hysteresis loops has been presented. Additionally, the areas of the obtained hysteresis loops, representing the energy loss per unit volume, have been calculated and the dependence of the energy loss on the frequency is shown. Furthermore, two models of the frequency dependence of the coercivity and two models of the energy loss separation have been used for fitting the experimental and simulation results. The relations between these models and their parameters have been observed and analysed. Also, the relations between parameters of the hysteresis model and the parameters of the energy loss separation models have been analysed and discussed. - Highlights: • A mathematical model of frequency-dependent hysteresis is proposed. • Dependence of coercivity and energy loss per unit volume on frequency is modelled. • Equivalence between models and relation between model parameters are presented.

  1. Magnetocrystalline anisotropy constants, rotational hysteresis energy and magnetic domain structure in UFe6Al6, UFe9AlSi2 and ScFe10Si2 intermetallic compounds

    International Nuclear Information System (INIS)

    Wyslocki, J.J.; Pawlik, P.; Wochowski, K.; Kotur, B.; Bodak, O.I.

    1996-01-01

    The magnetic torque, T, was applied to determine the anisotropy constants K 1 and K 2 of the UFe 6 Al 6 , UFe 9 AlSi 2 and ScFe 10 Si 2 compounds. The mechanism of magnetization reversal processes in these compounds was investigated on the basis of the analysis of the rotational hysteresis energy, W r and rotational hysteresis integral, R, calculated from the magnetic torque curves. Applying the powder pattern method, magnetic domain structures were observed. Moreover, the fundamental parameters of the domain structure were determined. (orig.)

  2. Hysteresis losses in a dense superparamagnetic nanoparticle assembly

    Directory of Open Access Journals (Sweden)

    S. A. Gudoshnikov

    2012-03-01

    Full Text Available The hysteresis losses of a dense assembly of magnetite nanoparticles with an average diameter D = 25 nm are measured in the frequency range f = 10 – 200 kHz for magnetic field amplitudes up to H0 = 400 Oe. The low frequency hysteresis loops of the assembly are obtained by means of integration of the electro-motive force signal arising in a small pick-up coil wrapped around a sample which contains 1 – 5 mg of a magnetite powder. It is proved experimentally that the specific absorption rate diminishes approximately 4.5 times when the sample aspect ratio decreases from 11.4 to 1. Theoretical estimate shows that experimentally measured hysteresis loops can be approximately described only by taking into account appreciable contributions of magnetic nanoparticles of both very small, D 30 nm, diameters. Thus the wide particle size distribution has to be assumed.

  3. Representation of microstructural features and magnetic anisotropy of electrical steels in an energy-based vector hysteresis model

    Directory of Open Access Journals (Sweden)

    Kevin Jacques

    2018-04-01

    Full Text Available This paper demonstrates how the statistical distribution of pinning fields in a ferromagnetic material can be identified systematically from standard magnetic measurements, Epstein frame or Single Sheet Tester (SST. The correlation between the pinning field distribution and microstructural parameters of the material is then analyzed.

  4. Representation of microstructural features and magnetic anisotropy of electrical steels in an energy-based vector hysteresis model

    Science.gov (United States)

    Jacques, Kevin; Steentjes, Simon; Henrotte, François; Geuzaine, Christophe; Hameyer, Kay

    2018-04-01

    This paper demonstrates how the statistical distribution of pinning fields in a ferromagnetic material can be identified systematically from standard magnetic measurements, Epstein frame or Single Sheet Tester (SST). The correlation between the pinning field distribution and microstructural parameters of the material is then analyzed.

  5. A Study of QMM Hysteresis Cycle Data. Field Linearity and Field Reproducibility

    International Nuclear Information System (INIS)

    Vernin, P.; Fonvieille, H.; Quemener, G.

    1997-08-01

    A study of the hysteresis data provided by the quadrupole field mapping of the HRS Electron Arm is presented. For each quad Q1, Q2, Q3, a series of runs was performed to obtain the hysteresis curve of the magnet at maximal current. The focus of the present document is not the field maps but a specific analysis of QMM data in terms of hysteresis curves, and field linearity as a function of the current. These measurements allow to put limits on the reproducibility of magnet setting for the presently used operating mode of the quads. (K.A.)

  6. Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles

    Directory of Open Access Journals (Sweden)

    Federico Chinni

    2017-06-01

    Full Text Available One fundamental requirement in the search for novel magnetic materials is the possibility of predicting and controlling their magnetic anisotropy and hence the overall hysteretic behavior. We have studied the magnetism of Au:Co films (~30 nm thick with concentration ratios of 2:1, 1:1, and 1:2, grown by magnetron sputtering co-deposition on natively oxidized Si substrates. They consist of a AuCo ferromagnetic alloy in which segregated ultrafine Co particles are dispersed (the fractions of Co in the AuCo alloy and of segregated Co increase with decreasing the Au:Co ratio. We have observed an unexpected hysteretic behavior characterized by in-plane anisotropy and crossed branches in the loops measured along the hard magnetization direction. To elucidate this phenomenon, micromagnetic calculations have been performed for a simplified system composed of two exchange-coupled phases: a AuCo matrix surrounding a Co cluster, which represents an aggregate of particles. The hysteretic features are qualitatively well reproduced provided that the two phases have almost orthogonal anisotropy axes. This requirement can be plausibly fulfilled assuming a dominant magnetoelastic character of the anisotropy in both phases. The achieved conclusions expand the fundamental knowledge on nanocomposite magnetic materials, offering general guidelines for tuning the hysteretic properties of future engineered systems.

  7. Magnetic Field Measurements in Beam Guiding Magnets

    CERN Document Server

    Henrichsen, K N

    1998-01-01

    Electromagnets used as beam guiding elements in particle accelerators and colliders require very tight tole-rances on their magnetic fields and on their alignment along the particle path. This article describes the methods and equipment used for magnetic measurements in beam transport magnets. Descriptions are given of magnetic resonance techniques, various induction coil methods, Hall generator measurements, the fluxgate magnetometer as well as the recently developed method of beam based alignment. References of historical nature as well as citations of recent work are given. The present commercial availability of the different sensors and asso-ciated equipment is indicated. Finally we shall try to analyze possible future needs for developments in those fields.

  8. A representation result for hysteresis operators with vector valued inputs and its application to models for magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Olaf, E-mail: Olaf.Klein@wias-berlin.de

    2014-02-15

    In this work, hysteresis operators mapping continuous vector-valued input functions being piecewise monotaffine, i.e. being piecewise the composition of a monotone with an affine function, to vector-valued output functions are considered. It is shown that the operator can be generated by a unique defined function on the convexity triple free strings. A formulation of a congruence property for periodic inputs is presented and reformulated as a condition for the generating string function.

  9. 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.

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

    KAUST Repository

    Ivanov, Yurii P.; del Real, R. P.; Chubykalo-Fesenko, O.; Vá zquez, M.

    2014-01-01

    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.

  11. Simultaneous measurement of hysteresis in capillary pressure and electric permittivity for multiphase flow through porous media

    NARCIS (Netherlands)

    Plug, W.J.; Slob, E.C.; Bruining, J.; Moreno Tirado, L.M.

    2007-01-01

    We present a tool that simultaneously measures the complex permittivity and the capillary pressure characteristics for multiphase flow. The sample holder is a parallel plate capacitor. A precision component analyzer is used to measure the impedance amplitude and phase angle as a function of

  12. Improvement in thrust force estimation of solenoid valve considering minor hysteresis loop

    Directory of Open Access Journals (Sweden)

    Myung-Hwan Yoon

    2017-05-01

    Full Text Available Solenoid valve is a very important hydraulic actuator for an automatic transmission in terms of shift quality. The same form of pressure for the clutch and the input current are required for an ideal control. However, the gap between a pressure and a current can occur which brings a delay in a transmission and a decrease in quality. This problem is caused by hysteresis phenomenon. As the ascending or descending magnetic field is applied to the solenoid, different thrust forces are generated. This paper suggests the calculation method of the thrust force considering the hysteresis phenomenon and consequently the accurate force can be obtained. Such hysteresis occurs in ferromagnetic materials, however the hysteresis phenomenon includes a minor hysteresis loop which begins with an initial magnetization curve and is generated by DC biased field density. As the core of the solenoid is ferromagnetic material, an accurate thrust force is obtained by applying the minor hysteresis loop compared to the force calculated by considering only the initial magnetization curve. An analytical background and the detailed explanation of measuring the minor hysteresis loop are presented. Furthermore experimental results and finite element analysis results are compared for the verification.

  13. Measurements of magnetic field alignment

    International Nuclear Information System (INIS)

    Kuchnir, M.; Schmidt, E.E.

    1987-01-01

    The procedure for installing Superconducting Super Collider (SSC) dipoles in their respective cryostats involves aligning the average direction of their field with the vertical to an accuracy of 0.5 mrad. The equipment developed for carrying on these measurements is described and the measurements performed on the first few prototypes SSC magnets are presented. The field angle as a function of position in these 16.6 m long magnets is a characteristic of the individual magnet with possible feedback information to its manufacturing procedure. A comparison of this vertical alignment characteristic with a magnetic field intensity (by NMR) characteristic for one of the prototypes is also presented. 5 refs., 7 figs

  14. Magnetic measurements under pressure

    Czech Academy of Sciences Publication Activity Database

    Zentková, M.; Arnold, Zdeněk; Mihalik, M.; Mihalik, M.; Zentko, A.; Kamarád, Jiří; Mitróová, Z.; Mat`aš, S.

    2006-01-01

    Roč. 57, 8/S (2006), s. 29-32 ISSN 1335-3632 Institutional research plan: CEZ:AV0Z10100521 Keywords : hydrostatic pressure * Prussian blue analogues * AC susceptibility * intermetallic compound * ferromagnetism * errimagnetism Subject RIV: BM - Solid Matter Physics ; Magnetism

  15. Vector hysteresis models

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Pavel

    1991-01-01

    Roč. 2, - (1991), s. 281-292 ISSN 0956-7925 Keywords : vector hysteresis operator * hysteresis potential * differential inequality Subject RIV: BA - General Mathematics http://www.math.cas.cz/~krejci/b15p.pdf

  16. 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)

  17. submitter Hysteresis Losses and Effective $J_{c}(B)$ Scaling Law for ITER Nb$_{3}$Sn Strands

    CERN Document Server

    Seiler, E; Bordini, B; Bottura, L; Bessette, D; Vostner, A; Devred, A

    2016-01-01

    Hysteresis losses of five Nb$_{3}$Sn International Thermonuclear Experimental Reactor reference strands were investigated by means of magnetization loop measurements in a vibrating sample magnetometer in a perpendicularly applied magnetic field. The magnetization loops were recorded while continuously sweeping the applied field between the extreme values $±B_m$, covering a wide range of maximum applied fields (0.2-10 T). In this paper, we compare the directly determined hysteresis losses based on the area of the smaller measured loops and the losses calculated by the integration of the width ΔM of the $B_m$ = 10 T magnetization loop. A suitable fitting function is proposed to describe the ΔM(B) dependence, which leads, for each strand, to an excellent agreement with the experimentally determined hysteresis losses, magnetization, and pinning force. Transport critical current measurements in a perpendicularly applied magnetic field were also performed for all the strands, and on the basis of the comparison w...

  18. Thermal behavior of dynamic magnetizations, hysteresis loop areas and correlations of a cylindrical Ising nanotube in an oscillating magnetic field within the effective-field theory and the Glauber-type stochastic dynamics approach

    International Nuclear Information System (INIS)

    Deviren, Bayram; Keskin, Mustafa

    2012-01-01

    The dynamical aspects of a cylindrical Ising nanotube in the presence of a time-varying magnetic field are investigated within the effective-field theory with correlations and Glauber-type stochastic approach. Temperature dependence of the dynamic magnetizations, dynamic total magnetization, hysteresis loop areas and correlations are investigated in order to characterize the nature of dynamic transitions as well as to obtain the dynamic phase transition temperatures and compensation behaviors. Some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and core, i.e., five different types of compensation behaviors in the Néel classification nomenclature exist in the system. -- Highlights: ► Kinetic cylindrical Ising nanotube is investigated using the effective-field theory. ► The dynamic magnetizations, hysteresis loop areas and correlations are calculated. ► The effects of the exchange interactions have been studied in detail. ► Five different types of compensation behaviors have been found. ► Some characteristic phenomena are found depending on ratio of physical parameters.

  19. Thermal behavior of dynamic magnetizations, hysteresis loop areas and correlations of a cylindrical Ising nanotube in an oscillating magnetic field within the effective-field theory and the Glauber-type stochastic dynamics approach

    Energy Technology Data Exchange (ETDEWEB)

    Deviren, Bayram, E-mail: bayram.deviren@nevsehir.edu.tr [Department of Physics, Nevsehir University, 50300 Nevsehir (Turkey); Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

    2012-02-20

    The dynamical aspects of a cylindrical Ising nanotube in the presence of a time-varying magnetic field are investigated within the effective-field theory with correlations and Glauber-type stochastic approach. Temperature dependence of the dynamic magnetizations, dynamic total magnetization, hysteresis loop areas and correlations are investigated in order to characterize the nature of dynamic transitions as well as to obtain the dynamic phase transition temperatures and compensation behaviors. Some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and core, i.e., five different types of compensation behaviors in the Néel classification nomenclature exist in the system. -- Highlights: ► Kinetic cylindrical Ising nanotube is investigated using the effective-field theory. ► The dynamic magnetizations, hysteresis loop areas and correlations are calculated. ► The effects of the exchange interactions have been studied in detail. ► Five different types of compensation behaviors have been found. ► Some characteristic phenomena are found depending on ratio of physical parameters.

  20. Magnetic hysteresis properties of nanocrystalline (Nd,Ho)-(Fe,Co)-Balloy after melt spinning, severe plastic deformation and subsequentheat treatment

    Czech Academy of Sciences Publication Activity Database

    Tereshina, I. S.; Pelevin, I.A.; Tereshina, Evgeniya; Burkhanov, G.S.; Rogacki, K.; Miller, M.; Kudrevatykh, N. V.; Markin, P.E.; Volegov, A.S.; Grechishkin, R.M.; Dobatkin, S.V.; Schultz, L.

    2016-01-01

    Roč. 681, Oct (2016), s. 555-560 ISSN 0925-8388 Institutional support: RVO:68378271 Keywords : high coercive magnetic materials * multistage treatment * melt spinning * severe plastic deformation * heat treatment Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.133, year: 2016

  1. The Characterization of the Magnetic Properties of Soft Magnetic Materials

    DEFF Research Database (Denmark)

    Larsen, Raino Michael

    1996-01-01

    The hysteresis curve and magnetic properties such as permeability, saturation induction, residual induction, coercive force and hysteresis losses are presented. The design and construction of equipment making it possible to measure true DC-values as well as AC-properties of toroid rings and cylin......The hysteresis curve and magnetic properties such as permeability, saturation induction, residual induction, coercive force and hysteresis losses are presented. The design and construction of equipment making it possible to measure true DC-values as well as AC-properties of toroid rings...

  2. 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.

  3. AA magnet measurement team

    CERN Multimedia

    CERN PhotoLab

    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.

  4. Hysteresis of magnetostructural transitions: Repeatable and non-repeatable processes

    Science.gov (United States)

    Provenzano, Virgil; Della Torre, Edward; Bennett, Lawrence H.; ElBidweihy, Hatem

    2014-02-01

    The Gd5Ge2Si2 alloy and the off-stoichiometric Ni50Mn35In15 Heusler alloy belong to a special class of metallic materials that exhibit first-order magnetostructural transitions near room temperature. The magnetic properties of this class of materials have been extensively studied due to their interesting magnetic behavior and their potential for a number of technological applications such as refrigerants for near-room-temperature magnetic refrigeration. The thermally driven first-order transitions in these materials can be field-induced in the reverse order by applying a strong enough field. The field-induced transitions are typically accompanied by the presence of large magnetic hysteresis, the characteristics of which are a complicated function of temperature, field, and magneto-thermal history. In this study we show that the virgin curve, the major loop, and sequentially measured MH loops are the results of both repeatable and non-repeatable processes, in which the starting magnetostructural state, prior to the cycling of field, plays a major role. Using the Gd5Ge2Si2 and Ni50Mn35In15 alloys, as model materials, we show that a starting single phase state results in fully repeatable processes and large magnetic hysteresis, whereas a mixed phase starting state results in non-repeatable processes and smaller hysteresis.

  5. Hysteresis of magnetostructural transitions: Repeatable and non-repeatable processes

    International Nuclear Information System (INIS)

    Provenzano, Virgil; Della Torre, Edward; Bennett, Lawrence H.; ElBidweihy, Hatem

    2014-01-01

    The Gd 5 Ge 2 Si 2 alloy and the off-stoichiometric Ni 50 Mn 35 In 15 Heusler alloy belong to a special class of metallic materials that exhibit first-order magnetostructural transitions near room temperature. The magnetic properties of this class of materials have been extensively studied due to their interesting magnetic behavior and their potential for a number of technological applications such as refrigerants for near-room-temperature magnetic refrigeration. The thermally driven first-order transitions in these materials can be field-induced in the reverse order by applying a strong enough field. The field-induced transitions are typically accompanied by the presence of large magnetic hysteresis, the characteristics of which are a complicated function of temperature, field, and magneto-thermal history. In this study we show that the virgin curve, the major loop, and sequentially measured MH loops are the results of both repeatable and non-repeatable processes, in which the starting magnetostructural state, prior to the cycling of field, plays a major role. Using the Gd 5 Ge 2 Si 2 and Ni 50 Mn 35 In 15 alloys, as model materials, we show that a starting single phase state results in fully repeatable processes and large magnetic hysteresis, whereas a mixed phase starting state results in non-repeatable processes and smaller hysteresis

  6. A simple model of hysteresis behavior using spreadsheet analysis

    International Nuclear Information System (INIS)

    Ehrmann, A; Blachowicz, T

    2015-01-01

    Hysteresis loops occur in many scientific and technical problems, especially as field dependent magnetization of ferromagnetic materials, but also as stress-strain-curves of materials measured by tensile tests including thermal effects, liquid-solid phase transitions, in cell biology or economics. While several mathematical models exist which aim to calculate hysteresis energies and other parameters, here we offer a simple model for a general hysteretic system, showing different hysteresis loops depending on the defined parameters. The calculation which is based on basic spreadsheet analysis plus an easy macro code can be used by students to understand how these systems work and how the parameters influence the reactions of the system on an external field. Importantly, in the step-by-step mode, each change of the system state, compared to the last step, becomes visible. The simple program can be developed further by several changes and additions, enabling the building of a tool which is capable of answering real physical questions in the broad field of magnetism as well as in other scientific areas, in which similar hysteresis loops occur

  7. A simple model of hysteresis behavior using spreadsheet analysis

    Science.gov (United States)

    Ehrmann, A.; Blachowicz, T.

    2015-01-01

    Hysteresis loops occur in many scientific and technical problems, especially as field dependent magnetization of ferromagnetic materials, but also as stress-strain-curves of materials measured by tensile tests including thermal effects, liquid-solid phase transitions, in cell biology or economics. While several mathematical models exist which aim to calculate hysteresis energies and other parameters, here we offer a simple model for a general hysteretic system, showing different hysteresis loops depending on the defined parameters. The calculation which is based on basic spreadsheet analysis plus an easy macro code can be used by students to understand how these systems work and how the parameters influence the reactions of the system on an external field. Importantly, in the step-by-step mode, each change of the system state, compared to the last step, becomes visible. The simple program can be developed further by several changes and additions, enabling the building of a tool which is capable of answering real physical questions in the broad field of magnetism as well as in other scientific areas, in which similar hysteresis loops occur.

  8. Modification of a commercial nanoindentation system for measurement of hysteresis cycles under mechanical load in polycrystalline ferroelectric films

    Directory of Open Access Journals (Sweden)

    Rivero, Doris

    2012-02-01

    Full Text Available A commercial hardness-tester by nanoindentation was modified to use metallic indenter tips for the measurement of hysteresis cycles of ferroelectric films under mechanical load and with high lateral resolution. A novel semi-automatic charge integrating module was developed to this aim. LabVIEW 8.6 graphical programming environment was used to control the data acquisition system (DAS, the sinusoidal high voltage generator (± 300V and the charge integrating module in the measurement of the loops. The software also provides data correction due to non-ferroelectric-switching contributions to obtain reliable remanent polarization (Pr and coercive field (Ec values. It also displays the loops both in polarization-fiel(P-E and current density-field (J-E modes. The experimental set-up was validated with measurements on dense PZT films (10μm on platinised Si substrates. Coherent cycles are obtained using the novel semi-automatic charge integrator , the classical Sawyer and Tower circuit and using an electrometer. Under low indentation load causing quasi-elastic strain, the loops do not show any artifact.

    Se ha modificado un nanoindentador comercial para el uso de puntas metálicas para la medida de ciclos de histéresis en láminas ferroeléctricas bajo carga mecánica y con alta resolución lateral. A este fin, se ha desarrollado un circuito integrador de carga semi-automático. Se ha utilizado el entorno de programación gráfica LabVIEW 8.6 para el control del sistema de adquisición de datos (SAD, un generador de alto voltaje sinusoidal (± 300V y el circuito integrador en la medida del ciclo. El software desarrollado también realiza la corrección de los ciclos por sustracción de las contribuciones no debidas a la inversión de la polarización ferroeléctrica en la obtención de valores fiables de polarización remanente (Pr y campo coercitivo (Ec. La representación del ciclo puede hacerse como

  9. Direct Hysteresis Heating of Catalytically Active Ni–Co Nanoparticles as Steam Reforming Catalyst

    DEFF Research Database (Denmark)

    Mortensen, Peter Mølgaard; Engbæk, Jakob Soland; Vendelbo, Søren Bastholm

    2017-01-01

    We demonstrated a proof-of-concept catalytic steam reforming flow reactor system heated only by supported magnetic nickel–cobalt nanoparticles in an oscillating magnetic field. The heat transfer was facilitated by the hysteresis heating in the nickel–cobalt nanoparticles alone. This produced...... a sufficient power input to equilibrate the reaction at above 780 °C with more than 98% conversion of methane. The high conversion of methane indicated that Co-rich nanoparticles with a high Curie temperature provide sufficient heat to enable the endothermic reaction, with the catalytic activity facilitated...... by the Ni content in the nanoparticles. The magnetic hysteresis losses obtained from temperature-dependent hysteresis measurements were found to correlate well with the heat generation in the system. The direct heating of the catalytic system provides a fast heat transfer and thereby overcomes the heat...

  10. Enhanced magnetic hysteresis in Ni-Mn-Ga single crystal and its influence on magneticshape memory effect

    Czech Academy of Sciences Publication Activity Database

    Heczko, Oleg; Drahokoupil, Jan; Straka, L.

    2015-01-01

    Roč. 117, č. 17 (2015), "17E703-1"-"17E703-4" ISSN 0021-8979 R&D Projects: GA ČR(CZ) GAP107/11/0391 Institutional support: RVO:68378271 Keywords : field-induced strain * temperature-dependence * alloy * martensite * Ni 2 MnGa * anisotropy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.101, year: 2015

  11. Magnetic moment measurement of magnetic nanoparticles using atomic force microscopy

    International Nuclear Information System (INIS)

    Park, J-W; Lee, E-C; Ju, H; Yoo, I S; Chang, W-S; Chung, B H; Kim, B S

    2008-01-01

    Magnetic moment per unit mass of magnetic nanoparticles was found by using the atomic force microscope (AFM). The mass of the nanoparticles was acquired from the resonance frequency shift of the particle-attached AFM probe and magnetic force measurement was also carried out with the AFM. Combining with magnetic field strength, the magnetic moment per unit mass of the nanoparticles was determined as a function of magnetic field strength. (technical design note)

  12. Magnetic measurements of suspended functionalised ferromagnetic beads under DC applied fields

    International Nuclear Information System (INIS)

    De Los Santos V, Luis; Llandro, Justin; Lee, Dongwook; Mitrelias, Thanos; Palfreyman, Justin J.; Hayward, Thomas J.; Cooper, Jos; Bland, J.A.C.; Barnes, Crispin H.W.; Arroyo C, Juan L.; Lees, Martin

    2009-01-01

    In this work, a simple technique to obtain the hysteresis loops of magnetic beads (Spherotech Inc.) in liquid suspension is presented. The magnetic measurements were taken in a DC Magnetic Property Measurement System (MPMS-SQUID sensor). Samples were based on ferromagnetic beads (surface-functionalized NH 2 , mean diameter 4.32 μm) prepared in three conditions: dry, suspended in sucrose solution and in suspension after functionalization with fluorophore. Special small containers (1.3 cm long) made of non magnetic plastic were designed to hold the beads in liquid. The results indicate that the bead's remnant magnetization is half of the value at maximum applied field in all cases. However, due to the additional degrees of rotational freedom, beads suspended in a liquid do not present coercivity. The use of ferromagnetic beads and magnetic elements of different architectures for applications in bioassays is also discussed.

  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. Electrical measurements during magnet construction

    International Nuclear Information System (INIS)

    Sintchak, G.; Ganetis, G.; Cottingham, G.

    1989-01-01

    Throughout the construction phase of the cold mass for SSC magnets, electrical tests are made to determine that no faults in the coil structure have developed. These tests include ones designed to measure turn-to-turn voltage hold-off, hypot tests to ground, coil resistance, and instrumentation checks. These various tests will be described and the test parameters that are used will be covered. 4 figs

  15. An application of the time-step topological model for three-phase transformer no-load current calculation considering hysteresis

    International Nuclear Information System (INIS)

    Carrander, Claes; Mousavi, Seyed Ali; Engdahl, Göran

    2017-01-01

    In many transformer applications, it is necessary to have a core magnetization model that takes into account both magnetic and electrical effects. This becomes particularly important in three-phase transformers, where the zero-sequence impedance is generally high, and therefore affects the magnetization very strongly. In this paper, we demonstrate a time-step topological simulation method that uses a lumped-element approach to accurately model both the electrical and magnetic circuits. The simulation method is independent of the used hysteresis model. In this paper, a hysteresis model based on the first-order reversal-curve has been used. - Highlights: • A lumped-element method for modelling transformers i demonstrated. • The method can include hysteresis and arbitrarily complex geometries. • Simulation results for one power transformer are compared to measurements. • An analytical curve-fitting expression for static hysteresis loops is shown.

  16. Low aperture magnetic elements measurements

    International Nuclear Information System (INIS)

    Aleksandrov, V.A.; Mikhajlichenko, A.A.; Parkhomchuk, V.V.; Seryj, A.A.; Shil'tsev, V.D.

    1991-01-01

    Two new methods of magnetic field measurements in low aperture elements are discussed. The first method uses thin magnetoresistive bismuth wire and the second-strained wire with AC. Principles of measuring used in the last technique are different from well known SLAC method of vibrating wire. Results of testing 0.38 T/mm quadrupole and VLEPP final focus test 3 T/mm lens are presented. Brief comparing of the lens axis determination precision of these methods is also discussed. 4 refs.; 8 figs

  17. Warm measurements of CBA superconducting magnets

    International Nuclear Information System (INIS)

    Engelmann, R.; Herrera, J.; Kahn, S.; Kirk, H.; Willen, E.; Yamin, P.

    1983-01-01

    We present results on magnetic field measurements of CBA dipole magnets in the warm (normal conductor) and cryogenic (superconducting) states. We apply two methods for the warm measurements, a dc and ac method. We find a good correlation between warm and cryogenic measurements which lends itself to a reliable diagnosis of magnet field errors using warm measurements early in the magnet assembly process. We further find good agreement between the two warm measurement methods, both done at low currents

  18. R&D ERL: Magnetic measurements of the ERL magnets

    Energy Technology Data Exchange (ETDEWEB)

    Jain, A.

    2010-08-01

    The magnet system of ERL consists of G5 solenoids, 6Q12 quadrupoles with 0.58 T/m gradient, 3D60 dipoles with 0.4 T central field, 15 and 30 degree Z-bend injection line dipole/quadrupole combined function magnets, and extraction line magnets. More details about the magnets can be found in a report by G. Mahler. Field quality in all the 6Q12 quadrupoles, 3D60 dipoles and the injection line magnets has been measured with either a rotating coil, or a Hall probe mapper. This report presents the results of these magnetic measurements.

  19. Research on low strain magnetic mechanical hysteresis damping performance of Fe-15Cr-3Mo-0.5Si alloy

    International Nuclear Information System (INIS)

    Wang, Hui; Huang, Huawei; Hong, Xiaofeng; Yin, Changgeng; Huang, Zhaohua; Chen, Le

    2015-01-01

    Highlights: • Heat treatment system has a great effect on the alloy damping performance. • Damping performance does not improve monotonously with temperature. • Furnace cooling is higher than that of alloy after air cooling. • There is an optimum annealing temperature and grain size to obtain high damping. - Abstract: This paper studies the preparation of Fe-15Cr-3Mo-0.5Si alloy by using vacuum induction melting furnace and vacuum annealing furnace, the damping performance of which in different heat treatment states is tested with dynamic mechanical thermal analyzer (DMA). Through microstructure observation with metallographic microscope (OM), grain boundary observation with scanning electron microscopy (SEM), phase structure analysis with X-ray diffraction (XRD) and internal stress of S-B model analysis, the effect law of annealing temperature, types of cooling, holding time and grain sizes on the damping performance of alloy and the related mechanism can be concluded as follows. The annealing temperature and grain sizes have a significant impact on the damping strain amplitude as well as the magnetic and mechanical damping performance of this ferromagnetic alloy. Proper annealing temperature and grain size is the necessary condition to get high damping performance of the alloy. It is not conducive to improvement of the damping performance if the annealing temperature is too high or too low and the grain size is too small or too large. For Fe-15Cr-3Mo-0.5Si alloy, within the range of the low strain amplitude, alloy damping performance does not improve monotonously with the increase of the annealing temperature and grain size. The maximum value appears at the annealing temperature of 1100 °C/1 h with the grain size of about 300 μm. At high annealing temperature of 1100 °C, the damping performance of alloy in the slow cooling furnace is higher than that with air cooling treatment. The extension or shortening of the holding time, to a certain extent

  20. Research on low strain magnetic mechanical hysteresis damping performance of Fe-15Cr-3Mo-0.5Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hui, E-mail: qinghe5525@163.com; Huang, Huawei; Hong, Xiaofeng; Yin, Changgeng; Huang, Zhaohua; Chen, Le

    2015-02-15

    Highlights: • Heat treatment system has a great effect on the alloy damping performance. • Damping performance does not improve monotonously with temperature. • Furnace cooling is higher than that of alloy after air cooling. • There is an optimum annealing temperature and grain size to obtain high damping. - Abstract: This paper studies the preparation of Fe-15Cr-3Mo-0.5Si alloy by using vacuum induction melting furnace and vacuum annealing furnace, the damping performance of which in different heat treatment states is tested with dynamic mechanical thermal analyzer (DMA). Through microstructure observation with metallographic microscope (OM), grain boundary observation with scanning electron microscopy (SEM), phase structure analysis with X-ray diffraction (XRD) and internal stress of S-B model analysis, the effect law of annealing temperature, types of cooling, holding time and grain sizes on the damping performance of alloy and the related mechanism can be concluded as follows. The annealing temperature and grain sizes have a significant impact on the damping strain amplitude as well as the magnetic and mechanical damping performance of this ferromagnetic alloy. Proper annealing temperature and grain size is the necessary condition to get high damping performance of the alloy. It is not conducive to improvement of the damping performance if the annealing temperature is too high or too low and the grain size is too small or too large. For Fe-15Cr-3Mo-0.5Si alloy, within the range of the low strain amplitude, alloy damping performance does not improve monotonously with the increase of the annealing temperature and grain size. The maximum value appears at the annealing temperature of 1100 °C/1 h with the grain size of about 300 μm. At high annealing temperature of 1100 °C, the damping performance of alloy in the slow cooling furnace is higher than that with air cooling treatment. The extension or shortening of the holding time, to a certain extent

  1. 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.

  2. Magnetic Barkhausen noise at different magnetization conditions

    Czech Academy of Sciences Publication Activity Database

    Stupakov, Alexandr; Perevertov, Oleksiy; Neslušan, M.

    2015-01-01

    Roč. 66, č. 7 (2015), s. 10-13 ISSN 1335-3632 R&D Projects: GA ČR GA13-18993S Institutional support: RVO:68378271 Keywords : Barkhausen noise * surface magnetic field * magnetization control * magnetic hysteresis * digital feedback loop Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 0.407, year: 2015

  3. Obesity does not influence the onset and offset of sevoflurane effect as measured by the hysteresis between sevoflurane concentration and bispectral index.

    Science.gov (United States)

    Cortínez, Luis I; Gambús, Pedro; Trocóniz, Iñaki F; Echevarría, Ghislaine; Muñoz, Hernán R

    2011-07-01

    The onset and offset of action of anesthetic gases might be delayed by respiratory changes and gas exchange alterations present in obese patients. In this study, we assessed the influence of obesity on the hysteresis between sevoflurane and its effect as measured by the bispectral index (BIS). Because the use of positive end-expiratory pressure (PEEP) in obese patients has improved gas exchange, we also assessed the influence of PEEP on hysteresis. Fifteen obese and 15 normal-weight patients, ASA physical status I and II, 20 to 50 years old, scheduled to undergo general anesthesia for elective laparoscopic surgery, were prospectively studied. Anesthesia was induced with propofol and maintained with sevoflurane and fentanyl. At the end of surgery and after stable BIS values of 60 to 65, the inspired concentration of sevoflurane was increased to 5 vol% for 5 minutes or until BIS was rate constant was not influenced by body mass index or PEEP (P > 0.05). Neither obesity nor PEEP showed any influence on the PK/PD descriptors. Our results do not support the hypothesis that obesity prolongs induction or recovery times when sevoflurane, a poorly soluble anesthetic, is used to maintain anesthesia from 90 to 120 minutes.

  4. Recent developments in magnet measuring techniques

    International Nuclear Information System (INIS)

    Billan, J.; Henrichsen, K.N.; Walckiers, L.

    1985-01-01

    The main problems related to magnetic measurements of particle accelerator components are discussed. Measurements of the properties of magnetic materials as well as the measurements of field distribution in the electromagnets for the Large Electron-Positron Collider (LEP) are illustrated. The fluxmeter method is extensively employed in this work. The impact of recent advances in electronic technology on measurement techniques is explained. Magnetic measurements (including the harmonic coil method) can be performed with improved accuracy applying modern technology to the classical methods. New methods for the non-destructive testing of magnetic materials and for the measurement of magnetic geometry are described. (orig.) [de

  5. A new family of 1D exchange biased heterometal single-molecule magnets: observation of pronounced quantum tunneling steps in the hysteresis loops of quasi-linear {Mn2Ni3} clusters.

    Science.gov (United States)

    Das, Animesh; Gieb, Klaus; Krupskaya, Yulia; Demeshko, Serhiy; Dechert, Sebastian; Klingeler, Rüdiger; Kataev, Vladislav; Büchner, Bernd; Müller, Paul; Meyer, Franc

    2011-03-16

    First members of a new family of heterometallic Mn/Ni complexes [Mn(2)Ni(3)X(2)L(4)(LH)(2)(H(2)O)(2)] (X = Cl: 1; X = Br: 2) with the new ligand 2-{3-(2-hydroxyphenyl)-1H-pyrazol-1-yl}ethanol (H(2)L) have been synthesized, and single crystals obtained from CH(2)Cl(2) solutions have been characterized crystallographically. The molecular structures feature a quasi-linear Mn(III)-Ni(II)-Ni(II)-Ni(II)-Mn(III) core with six-coordinate metal ions, where elongated axes of all the distorted octahedral coordination polyhedra are aligned parallel and are fixed with respect to each other by intramolecular hydrogen bonds. 1 and 2 exhibit quite strong ferromagnetic exchange interactions throughout (J(Mn-Ni) ≈ 40 K (1) or 42 K (2); J(Ni-Ni) ≈ 22 K (1) or 18 K (2)) that lead to an S(tot) = 7 ground state, and a sizable uniaxial magnetoanisotropy with D(mol) values -0.55 K (1) and -0.45 K (2). These values are directly derived also from frequency- and temperature-dependent high-field EPR spectra. Slow relaxation of the magnetization at low temperatures and single-molecule magnet (SMM) behavior are evident from frequency-dependent peaks in the out-of-phase ac susceptibilities and magnetization versus dc field measurements, with significant energy barriers to spin reversal U(eff) = 27 K (1) and 22 K (2). Pronounced quantum tunnelling steps are observed in the hysteresis loops of the temperature- and scan rate-dependent magnetization data, but with the first relaxation step shifted above (1) or below (2) the zero crossing of the magnetic field, despite the very similar molecular structures. The different behavior of 1 and 2 is interpreted in terms of antiferromagnetic (1) or ferromagnetic (2) intermolecular interactions, which are discussed in view of the subtle differences of intermolecular contacts within the crystal lattice.

  6. Magnetic field measurements and mapping techniques

    CERN Multimedia

    CERN. Geneva

    2003-01-01

    These lectures will present an overview of the most common techniques used for the measurement of magnetic field in accelerator magnets. The formalism for a harmonic description of the magnetic field will be presented, including a discussion of harmonics allowed under various types of symmetries in the magnet. The harmonic coil technique for measurement of field harmonics will be covered in depth. Using examples from recent projects, magnetic measurements will be shown to be a powerful tool for monitoring magnet production. Measurements of magnetic axis using extensions of the harmonic coil technique, as well as other techniques, such as the colloidal cell and stretched wire, will be covered. Topics of interest in superconducting magnets, such as time decay and snapback, requiring relatively fast measurements of the harmonics, will also be described.

  7. Measurement system for SSRF pulsed magnets

    International Nuclear Information System (INIS)

    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 simulation. (authors)

  8. Measurements of Solar Vector Magnetic Fields

    Science.gov (United States)

    Hagyard, M. J. (Editor)

    1985-01-01

    Various aspects of the measurement of solar magnetic fields are presented. The four major subdivisions of the study are: (1) theoretical understanding of solar vector magnetic fields; (3) techniques for interpretation of observational data; and (4) techniques for data display.

  9. Measurements of Solar Vector Magnetic Fields

    International Nuclear Information System (INIS)

    Hagyard, M.J.

    1985-05-01

    Various aspects of the measurement of solar magnetic fields are presented. The four major subdivisions of the study are: (1) theoretical understanding of solar vector magnetic fields; (3) techniques for interpretation of observational data; and (4) techniques for data display

  10. Systematic magnetization measurements on single crystalline Bi2Sr2CaCu2O8+δ with columnar defects

    International Nuclear Information System (INIS)

    Kimura, Kazuhiro; Koshida, Ryo; Kwok, W.K.; Crabtree, G.W.; Okayasu, Satoru; Sataka, Masao; Kazumata, Yukio; Kadowaki, Kazuo

    1999-01-01

    The authors have performed systematic magnetization measurements on single crystalline Bi 2 Sr 2 CaCu 2 O 8+δ with columnar defects of B Φ = 0.005 to 1 T by using a SQUID magnetometer. Magnetization hysteresis curves of the pristine sample show a weak irreversible behavior in the vortex liquid state, suggesting the existence of the new vortex state in the vortex liquid state. This weak irreversible region persists systematically in the samples with columnar defects even up to B Φ = 1 T. It is shown that the weak hysteresis of magnetization is sensitive to the disorder level of the sample and shifts systematically to higher temperature and field region with increasing the number of columnar defects. This behavior clearly indicates that effective pinning mechanism exists even in the vortex liquid state and generates a finite critical current

  11. Mathematical models of hysteresis

    International Nuclear Information System (INIS)

    1998-01-01

    The ongoing research has largely been focused on the development of mathematical models of hysteretic nonlinearities with nonlocal memories. The distinct feature of these nonlinearities is that their current states depend on past histories of input variations. It turns out that memories of hysteretic nonlinearities are quite selective. Indeed, experiments show that only some past input extrema (not the entire input variations) leave their marks upon future states of hysteretic nonlinearities. Thus special mathematical tools are needed in order to describe nonlocal selective memories of hysteretic nonlinearities. The origin of such tools can be traced back to the landmark paper of Preisach. Their research has been primarily concerned with Preisach-type models of hysteresis. All these models have a common generic feature; they are constructed as superpositions of simplest hysteretic nonlinearities-rectangular loops. During the past four years, the study has been by and large centered around the following topics: (1) further development of Scalar and vector Preisach-type models of hysteresis; (2) experimental testing of Preisach-type models of hysteresis; (3) development of new models for viscosity (aftereffect) in hysteretic systems; (4) development of mathematical models for superconducting hysteresis in the case of gradual resistive transitions; (5) software implementation of Preisach-type models of hysteresis; and (6) development of new ideas which have emerged in the course of the research work. The author briefly describes the main scientific results obtained in the areas outlined above

  12. Mathematical models of hysteresis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-08-01

    The ongoing research has largely been focused on the development of mathematical models of hysteretic nonlinearities with nonlocal memories. The distinct feature of these nonlinearities is that their current states depend on past histories of input variations. It turns out that memories of hysteretic nonlinearities are quite selective. Indeed, experiments show that only some past input extrema (not the entire input variations) leave their marks upon future states of hysteretic nonlinearities. Thus special mathematical tools are needed in order to describe nonlocal selective memories of hysteretic nonlinearities. The origin of such tools can be traced back to the landmark paper of Preisach. Their research has been primarily concerned with Preisach-type models of hysteresis. All these models have a common generic feature; they are constructed as superpositions of simplest hysteretic nonlinearities-rectangular loops. During the past four years, the study has been by and large centered around the following topics: (1) further development of Scalar and vector Preisach-type models of hysteresis; (2) experimental testing of Preisach-type models of hysteresis; (3) development of new models for viscosity (aftereffect) in hysteretic systems; (4) development of mathematical models for superconducting hysteresis in the case of gradual resistive transitions; (5) software implementation of Preisach-type models of hysteresis; and (6) development of new ideas which have emerged in the course of the research work. The author briefly describes the main scientific results obtained in the areas outlined above.

  13. Ferromagnetic hysteresis and the effective field

    NARCIS (Netherlands)

    Naus, H.W.L.

    2002-01-01

    The Jiles-Atherton model of the behavior of ferromagnetic materials determines the irreversible magnetization from the effective field by using a differential equation. This paper presents an exact, analytical solution to the equation, one displaying hysteresis. The inclusion of magnetomechanical

  14. Accurate method of the magnetic field measurement of quadrupole magnets

    International Nuclear Information System (INIS)

    Kumada, M.; Sakai, I.; Someya, H.; Sasaki, H.

    1983-01-01

    We present an accurate method of the magnetic field measurement of the quadrupole magnet. The method of obtaining the information of the field gradient and the effective focussing length is given. A new scheme to obtain the information of the skew field components is also proposed. The relative accuracy of the measurement was 1 x 10 -4 or less. (author)

  15. Measurements of magnetic field sources in schools

    International Nuclear Information System (INIS)

    Johnson, G.B.

    1992-01-01

    The Electrical Systems Division of the Electric Power Research Institute (EPRI) has initiated several research projects to investigate magnetic field levels, their characteristics, and their sources. This paper describes measurements of magnetic field sources in schools. Magnetic field measurements were made at four schools in the service areas of two utility companies. Magnetic field measurements included profiles of the magnetic field versus distance near power lines, around the perimeter of the school buildings, and at several locations within each school. Twenty-four hour measurements were also made to record the temporal variation of the magnetic field at several locations at each school. The instrumentation, measurement techniques, and magnetic field sources identified are discussed

  16. Magnetic Field Measurements of the GOLIATH Magnet in EHN1

    CERN Document Server

    Rosenthal, Marcel; Chatzidaki, Panagiota; Margraf, Rachel; Wilkens, Henric; Bergsma, Felix; Giudici, Pierre-Ange; CERN. Geneva. ATS Department

    2018-01-01

    This note describes the measurement campaign of the magnetic field of the GOLIATH magnet conducted in 2017. It documents the applied measurement procedure and the consecutive analysis of the recorded data. The shape of the magnetic field along the beam axis is discussed and compared with a previous measurement taken in the 1980s. Overall a very good agreement of both data sets is observed. The integrated vertical magnetic field is obtained by analytical descriptions fitted to the data. Additionally, the influence of different configurations of the power converters, as for example in the case of a differ- ent powering scheme of the upper and lower coil of the GOLIATH magnet, on the magnetic field are discussed.

  17. A dynamic method for magnetic torque measurement

    Science.gov (United States)

    Lin, C. E.; Jou, H. L.

    1994-01-01

    In a magnetic suspension system, accurate force measurement will result in better control performance in the test section, especially when a wider range of operation is required. Although many useful methods were developed to obtain the desired model, however, significant error is inevitable since the magnetic field distribution of the large-gap magnetic suspension system is extremely nonlinear. This paper proposed an easy approach to measure the magnetic torque of a magnetic suspension system using an angular photo encoder. Through the measurement of the velocity change data, the magnetic torque is converted. The proposed idea is described and implemented to obtain the desired data. It is useful to the calculation of a magnetic force in the magnetic suspension system.

  18. Understanding Unemployment Hysteresis

    DEFF Research Database (Denmark)

    Møller, Niels Framroze

    What explains the persistence of unemployment? The literature on hysteresis, which is based on unit root testing in autoregressive models, consists of a vast number of univariate studies, i.e. that analyze unemployment series in isolation, but few multivariate analyses that focus on the sources...... of hysteresis. As a result, this question remains largely unanswered. This paper presents a multivariate econometric framework for analyzing hysteresis, which allows one to test different hypotheses about non-stationarity of unemployment against one another. For example, whether this is due to a persistently...... to UK quarterly data on prices, wages, output, unemployment and crude oil prices, suggests that, for the period 1988 up to the onset of the …financial crisis, the non-stationarity of UK unemployment cannot be explained as a result of slow adjustment, including sluggish wage formation as emphasized...

  19. Magnetic measurements at Lawrence Berkeley Laboratory

    International Nuclear Information System (INIS)

    Green, M.I.; Barale, P.; Callapp, L.; Case-Fortier, M.; Lerner, D.; Nelson, D.; Schermer, R.; Skipper, G.; Van Dyke, D.; Cork, C.; Halbach, K.; Hassenzahl, W.; Hoyer, E.; Marks, S.; Harten, T.; Luchini, K.; Milburn, J.; Tanabe, J.; Zucca, F.; Keller, R.; Selph, F.; Gilbert, W.; Green, M.A.; O'Neil, J.; Schafer, R.; Taylor, C.; Greiman, W.; Hall, D.; MacFarlane, J.

    1991-08-01

    Recent magnetic measurement activities at LBL have been concentrated in two separate areas, electro-magnets and permanent magnets for the Advanced Light Source (ALS), and superconducting magnets for the Superconducting Super Collider Laboratory (SSCL). A survey of the many different measurement systems is presented. These include: AC magnetic measurements of an ALS booster dipole engineering model magnet, dipole moment measurements of permanent magnet blocks for ALS wigglers and undulators, permeability measurements of samples destined for wiggler and undulator poles, harmonic error analysis of SSC one meter model dipoles and quadrupoles and five meter long SSC prototype quadrupoles, harmonic error analysis of ALS dipoles, quadrupoles, and sextupoles, precision Hall probe mapping of ALS storage ring combined function magnets, and the design of the ALS insertion device magnets mapping system. We also describe a new UNIX based data acquisition system that is being developed for the SSC. Probes used for magnetic measurements include Helmholtz coils, integral coils, point coils, and bucking harmonic analysis coils, several different types of Hall probes, and nuclear magnetic resonance magnetometers. Both analog and digital integrators are used with the coils. Some problems that occurred and their rectification is described. The mechanisms used include rotating systems with optical encoders, X-Y mapping systems with optical encoders and a laser position measuring device. 10 refs., 3 figs., 1 tab

  20. Magnetic field measurements of the superEBIS superconducting magnet

    International Nuclear Information System (INIS)

    Herschcovitch, A.; Kponou, A.; Clipperton, R.; Hensel, W.; Usack, F.

    1994-01-01

    SuperEBIS was designed to have a solenoidal magnetic field of a 5 Tesla strength with a 120 cm long bore. The field was specified to be straight within 1 part in 10000 within the bore, and uniform to within 1 part in 1000 within the central 90 cm. Magnetic field measurements were performed with a computerized magnetic field measuring setup that was borrowed from W. Sampson's group. A preliminary test was made of a scheme to determine if the magnetic and mechanical axes of the solenoid coincided, and, if not, by how much

  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. Surface magnetic anisotropy in glass-coated amorphous microwires as determined from ferromagnetic resonance measurements

    International Nuclear Information System (INIS)

    Garcia-Miquel, H.; Garcia, J.M.; Garcia-Beneytez, J.M.; Vazquez, M.

    2001-01-01

    The ferromagnetic resonance frequency of different Co base glass-coated amorphous magnetic microwires about 3.5 μm in diameter with negative, vanishing and positive magnetostriction has been investigated from power absorption measurements in the microwave frequency range. The experimental technique employed here involves the replacement of the dielectric of a coaxial transmission line by the sample to be measured. From the evolution of the resonance frequency with DC applied magnetic field, the surface magnetic anisotropy field of the microwires has been quantitatively obtained and, as expected, found to depend on the sign and strength of the magnetostriction. Similar values for the surface anisotropy are obtained in comparison with bulk anisotropy as determined from quasi-static hysteresis loops measurements

  4. Magnetic measurements at Lawrence Berkeley Laboratory

    International Nuclear Information System (INIS)

    Green, M.I.; Barale, P.; Callapp, L.; Case-Fortier, M.; Lerner, D.; Nelson, D.; Schermer, R.; Skipper, G.; Van Dyke, D.; Cork, C.

    1992-01-01

    Recent magnetic measurement activities at LBL have been concentrated in two separate areas, electro-magnets and permanent magnets for the Advanced Light Source (ALS), and superconducting magnets for the Superconducting Super Collider Laboratory (SSCL). In this paper a survey of the many different measurement systems is presented. These include: AC magnetic measurements of an ALS booster dipole engineering model magnet, dipole moment measurements of permanent magnet blocks for ALS wigglers and undulators, permeability measurements of samples destined for wiggler and undulator poles, harmonic error analysis of SSC one meter model dipoles and quadrupoles and five meter long SSC prototype quadrupoles, harmonic error analysis of ALS dipoles, quadrupoles, and sextupoles, precision Hall probe mapping of ALS design of the ALS insertion device magnetic mapping system. The authors also describe a new UNIX based data acquisition system that is being developed for the SSC. Probes used for magnetic measurements include Helmholtz coils, integral coils, point coils, and bucking harmonic analysis coils, several different types of Hall probes, and nuclear magnetic resonance magnetometers

  5. Improving the performance of hysteresis direct torque control of ...

    Indian Academy of Sciences (India)

    Hysteresis direct torque control (HDTC) of an interior permanent magnet synchronous motor ... response, and improved the quality of the current waveforms. Luukko ..... LF , however, the cost and size of the AF increases, and therefore suitable ...

  6. Parameterization and measurements of helical magnetic fields

    International Nuclear Information System (INIS)

    Fischer, W.; Okamura, M.

    1997-01-01

    Magnetic fields with helical symmetry can be parameterized using multipole coefficients (a n , b n ). We present a parameterization that gives the familiar multipole coefficients (a n , b n ) for straight magnets when the helical wavelength tends to infinity. To measure helical fields all methods used for straight magnets can be employed. We show how to convert the results of those measurements to obtain the desired helical multipole coefficients (a n , b n )

  7. The Bilinear Product Model of Hysteresis Phenomena

    Science.gov (United States)

    Kádár, György

    1989-01-01

    In ferromagnetic materials non-reversible magnetization processes are represented by rather complex hysteresis curves. The phenomenological description of such curves needs the use of multi-valued, yet unambiguous, deterministic functions. The history dependent calculation of consecutive Everett-integrals of the two-variable Preisach-function can account for the main features of hysteresis curves in uniaxial magnetic materials. The traditional Preisach model has recently been modified on the basis of population dynamics considerations, removing the non-real congruency property of the model. The Preisach-function was proposed to be a product of two factors of distinct physical significance: a magnetization dependent function taking into account the overall magnetization state of the body and a bilinear form of a single variable, magnetic field dependent, switching probability function. The most important statement of the bilinear product model is, that the switching process of individual particles is to be separated from the book-keeping procedure of their states. This empirical model of hysteresis can easily be extended to other irreversible physical processes, such as first order phase transitions.

  8. Programming the control of magnetic field measurements

    International Nuclear Information System (INIS)

    David, L.

    1998-01-01

    This paper gives a short review concerning the new NMR probe measurement control system. Then it presents the new program 'CYCLOCHAMP' attached to the magnetic field measurement which also allows to cycle the magnetic field inside the cyclotrons and to equilibrate it among the SSC sectors. (authors)

  9. Fringing field measurement of dipole magnet

    International Nuclear Information System (INIS)

    Lu Hongyou; Jiang Weisheng; Mao Naifeng; Mao Xingwang

    1985-01-01

    The fringing field of a dipole magnet with a C-type circuit and homogeneous field in the gap has been measured including the distributions of fringing fields with and without magnetic shield. The measured data was analyzed by using the concept of virtual field boundary

  10. 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...

  11. The measurement of solar magnetic fields

    International Nuclear Information System (INIS)

    Stenflo, J.O.

    1978-01-01

    Solar activity is basically caused by the interaction between magnetic fields, solar rotation and convective motions. Detailed mapping of the Sun's rapidly varying magnetic field helps in the understanding of the mechanisms of solar activity. Observations in recent years have revealed unexpected and intriguing properties of solar magnetic fields, the explanation of which has become a challenge to plasma physicists. This review deals primarily with how the Sun's magnetic field is measured, but it also includes a brief review of the present observational picture of the magnetic field, which is needed to understand the problems of how to properly interpret the observations. 215 references. (author)

  12. 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...

  13. Lightning magnetic field measuring system in Bogota

    OpenAIRE

    Escobar Alvarado, Oscar Fernardo

    2013-01-01

    This thesis presents the configuration and performance of a lightning radiated electromagnetic field measuring system in Bogotá Colombia. The system is composed by both magnetic and electric field measuring systems working as separated sensors. The aim of the thesis is the design and construction of a Magnetic Field Measuring System and the implementation of a whole lightning measuring system in Bogotá. The theoretical background, design process, construction and implementation of the system ...

  14. Magnetic Field Measurements In Magnetized Plasmas Using Zeeman Broadening Diagnostics

    Science.gov (United States)

    Haque, Showera; Wallace, Matthew; Presura, Radu; Neill, Paul

    2017-10-01

    The Zeeman effect has been used to measure the magnetic field in high energy density plasmas. This method is limited when plasma conditions are such that the line broadening due to the high plasma density and temperature surpasses the Zeeman splitting. We have measured magnetic fields in magnetized laser plasmas under conditions where the Zeeman splitting was not spectrally resolved. The magnetic field strength was determined from the difference in widths of two doublet components, using an idea proposed by Tessarin et al. (2011). Time-gated spectra with one-dimensional space-resolution were obtained at the Nevada Terawatt Facility for laser plasmas created by 20 J, 1 ns Leopard laser pulses, and expanding in the azimuthal magnetic field produced by the 0.6 MA Zebra pulsed power generator. We explore the response of the Al III 4s 2S1/2 - 4p 2P1 / 2 , 3 / 2 doublet components to the external magnetic field spatially along the plasma. Radial magnetic field and electron density profiles were measured within the plasma plume. This work was supported by the DOE/OFES Grant DE-SC0008829 and DOE/NNSA contract DE-FC52-06NA27616.

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

    International Nuclear Information System (INIS)

    Khatiwada, R; Kendrick, R; Khosravi, M; Peters, M; Smith, E; Snow, W M; Dennis, L

    2016-01-01

    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 experimental error. These results verify the well-known Wiedemann additivity law for the magnetic susceptibility of inert mixtures of materials and thereby realize the ability to produce materials with small but tunable magnetic susceptibility. For our particular scientific application, we are also looking for materials with the largest possible number of neutrons and protons per unit volume. The gallium–indium alloys fabricated and measured in this work possess to our knowledge the smallest ratio of volume magnetic susceptibility to nucleon number density per unit volume for a room temperature liquid, and the tungsten-bismuth pressed powder mixtures possess to our knowledge the smallest ratio of volume magnetic susceptibility to nucleon number density per unit volume for a room temperature solid. This ratio is a figure of merit for a certain class of precision experiments that search for possible exotic spin-dependent forces of Nature. (paper)

  16. Superconducting property measuring system by magnetization method

    International Nuclear Information System (INIS)

    Ikisawa, K.; Mori, T.; Takasu, N.

    1988-01-01

    Superconducting property measuring system (CMS-370B) for high temperature oxide superconductor has been developed. This system adopts magnetization measurement. The superconducting properties are able to be measured automatically and continuously changing the temperature and external magnetic field. The critical current density as a function of temperature and magnetic field of high temperature superconductor YBa 2 Cu 3 O 7-y (YBCO) has been measured. This paper reports how it was confirmed that this system having the high performance and the accuracy gave the significant contribution to the superconducting material development

  17. Ac loss measurement of SSC dipole magnets

    International Nuclear Information System (INIS)

    Delchamps, S.; Hanft, R.; Jaffery, T.; Kinney, W.; Koska, W.; Lamm, M.J.; Mazur, P.O.; Orris, D.; Ozelis, J.P.; Strait, J.; Wake, M.

    1992-09-01

    AC losses in full length and 1.5 m model SSC collider dipoles were successfully measured by the direct observation of energy flow into and out of magnets during a ramp cycle. The measurement was performed by using two double-integrating type digital volt meters (DVM's) for current and voltage measurement. Measurements were performed for six is m long ASST magnets and five 1.5 m long model magnets, inducting one 40 mm diameter magnet. There were large variations in the eddy current losses. Since these magnets use conductors with slight deviations in their internal structures and processing of the copper surface depending on the manufacturer, it is likely that there are differences in the contact resistance between strands. Correlation between the ramp rate dependence of the,quench current and the eddy current loss was evident

  18. Stereo Hysteresis Revisited

    Directory of Open Access Journals (Sweden)

    Christopher Tyler

    2012-05-01

    Full Text Available One of the most fascinating phenomena in stereopsis is the profound hysteresis effect reported by Fender and Julesz (1967, in which the depth percept persisted with increasing disparity long past the point at which depth was recovered with decreasing disparity. To control retinal disparity without vergence eye movements, they stabilized the stimuli on the retinas with an eye tracker. I now report that stereo hysteresis can be observed directly in printed stereograms simply by rotating the image. As the stereo image rotates, the horizontal disparities rotate to become vertical, then horizontal with inverted sign, and then vertical again before returning to the original orientation. The depth shows an interesting popout effect, almost as though the depth was turning on and off rapidly, despite the inherently sinusoidal change in the horizontal disparity vector. This stimulus was generated electronically in a circular format so that the random-dot field could be dynamically replaced, eliminating any cue to cyclorotation. Noise density was scaled with eccentricity to fade out the stimulus near fixation. For both the invariant and the dynamic noise, profound hysteresis of several seconds delay was found in six observers. This was far longer than the reaction time to respond to changes in disparity, which was less than a second. Purely horizontal modulation of disparity to match the horizontal vector component of the disparity rotation did not show the popout effect, which thus seems to be a function of the interaction between horizontal and vertical disparities and may be attributable to depth interpolation processes.

  19. Measurement of magnetic fluctuation induced energy transport

    International Nuclear Information System (INIS)

    Fiksel, G.; Prager, S.C.; Shen, W.; Stoneking, M.

    1993-11-01

    The local electron energy flux produced by magnetic fluctuations has been measured directly in the MST reversed field pinch (over the radial range r/a > 0.75). The flux, produced by electrons traveling parallel to a fluctuating magnetic field, is obtained from correlation between the fluctuations in the parallel heat flux and the radial magnetic field. The fluctuation induced flux is large (100 kW/cm 2 ) in the ''core'' (r/a 2 ) in the edge

  20. Measurement of the magnetic field coefficients of particle accelerator magnets

    International Nuclear Information System (INIS)

    Herrera, J.; Ganetis, G.; Hogue, R.; Rogers, E.; Wanderer, P.; Willen, E.

    1989-01-01

    An important aspect in the development of magnets to be used in particle accelerators is the measurement of the magnetic field in the beam aperture. In general it is necessary to measure the harmonic multipoles in the dipole, quadrupole, and sextupole magnets for a series of stationary currents (plateaus). This is the case for the Superconducting Super Collider (SSC) which will be ramped to high field over a long period (/approximately/1000 sec.) and then remain on the flat top for the duration of the particle collision phase. In contrast to this mode of operation, the Booster ring being constructed for the Brookhaven AGS, will have a fast ramp rate of approximately 10 Hz. The multipole fields for these Booster magnets must therefore be determined ''on the ramp.'' In this way the effect of eddy currents will be taken into account. The measurement system which we will describe in this paper is an outgrowth of that used for the SSC dipoles. It has the capability of measuring the field multipoles on both a plateau or during a fast ramp. In addition, the same basic coil assembly is used to obtain the magnetic multipoles in dipole, quadrupole, and sextupole magnets. 2 refs., 3 figs., 1 tab

  1. Experimental comparison of rate-dependent hysteresis models in characterizing and compensating hysteresis of piezoelectric tube actuators

    Energy Technology Data Exchange (ETDEWEB)

    Aljanaideh, Omar, E-mail: omaryanni@gmail.com [Department of Mechanical Engineering, The University of Jordan, Amman 11942 (Jordan); Habineza, Didace; Rakotondrabe, Micky [AS2M department, FEMTO-ST Institute, Univ. Bourgogne Franche-Comté, Univ. de Franche-Comté/CNRS/ENSMM, 25000 Besançon (France); Al Janaideh, Mohammad [Department of Mechanical and Industrial Engineering, The Mechatronics and Microsystems Design Laboratory, University of Toronto (Canada); Department of Mechatronics Engineering, The University of Jordan, Amman 11942 (Jordan)

    2016-04-01

    An experimental study has been carried out to characterize rate-dependent hysteresis of a piezoelectric tube actuator at different excitation frequencies. The experimental measurements were followed by modeling and compensation of the hysteresis nonlinearities of the piezoelectric tube actuator using both the inverse rate-dependent Prandtl–Ishlinskii model (RDPI) and inverse rate-independent Prandtl–Ishlinskii model (RIPI) coupled with a controller. The comparison of hysteresis modeling and compensation of the actuator with both models is presented.

  2. Experimental comparison of rate-dependent hysteresis models in characterizing and compensating hysteresis of piezoelectric tube actuators

    International Nuclear Information System (INIS)

    Aljanaideh, Omar; Habineza, Didace; Rakotondrabe, Micky; Al Janaideh, Mohammad

    2016-01-01

    An experimental study has been carried out to characterize rate-dependent hysteresis of a piezoelectric tube actuator at different excitation frequencies. The experimental measurements were followed by modeling and compensation of the hysteresis nonlinearities of the piezoelectric tube actuator using both the inverse rate-dependent Prandtl–Ishlinskii model (RDPI) and inverse rate-independent Prandtl–Ishlinskii model (RIPI) coupled with a controller. The comparison of hysteresis modeling and compensation of the actuator with both models is presented.

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

    International Nuclear Information System (INIS)

    Bottura, L.; Buzio, M.; Deferne, G.; Sievers, P.; Smirnov, N.; Villar, F.P.; Walckiers, L.

    1999-01-01

    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)

  4. Evaluation of microstructural difference in low alloy steel (SA508 CI.3) by magnetic measurements

    International Nuclear Information System (INIS)

    Chi, Se Hwan; Park, Duck Gun; Hong, Jun Hwa; Kuk, Il Hium; Song, Sook Hyang; Shur, Dong Soo

    1997-01-01

    Magnetic measurements on SA 508 Cl. 3 low alloy reactor pressure vessel (RPV) steels of three different refining processes were conducted to prepare baseline magnetic properties for future comparison with that of irradiated one and to examine the correlation between microstructures and magnetic parameters. TEM(transmission electron microscopy) on thin films and carbon replications were performed for microstructural investigation, and microhardness, tensile and fracture toughness tests were conducted for mechanical properties measurement. Barkhausen noise analysis was conducted and hysteresis parameters were measured. Microstructure, mechanist and magnetic properties were interpreted together to explore their inter-relationship. Also the applicability of a magnetic nondestructive evaluation method for monitoring fine microstructural changes in low alloy steels of complicated microstructure was examined. The results showed that, of all magnetic parameters, Barkhausen noise amplitudes show consistent change with microstructure (grain size, carbide microstructure, lath width) and hardness of the materials. For monitoring microstructural and mechanical property changes of low alloy steel under service environment of reactor pressure vessel steels, Barkhausen noise amplitude and coercivity appear to be as key magnetic parameters useful for nondestructive evaluation.

  5. A wide-frequency range AC magnetometer to measure the specific absorption rate in nanoparticles for magnetic hyperthermia

    International Nuclear Information System (INIS)

    Garaio, E.; Collantes, J.M.; Garcia, J.A.; Plazaola, F.; Mornet, S.; Couillaud, F.; Sandre, O.

    2014-01-01

    Measurement of specific absorption rate (SAR) of magnetic nanoparticles is crucial to assert their potential for magnetic hyperthermia. To perform this task, calorimetric methods are widely used. However, those methods are not very accurate and are difficult to standardize. In this paper, we present AC magnetometry results performed with a lab-made magnetometer that is able to obtain dynamic hysteresis-loops in the AC magnetic field frequency range from 50 kHz to 1 MHz and intensities up to 24 kA m −1 . In this work, SAR values of maghemite nanoparticles dispersed in water are measured by AC magnetometry. The so-obtained values are compared with the SAR measured by calorimetric methods. Both measurements, by calorimetry and magnetometry, are in good agreement. Therefore, the presented AC magnetometer is a suitable way to obtain SAR values of magnetic nanoparticles. - Highlights: • We propose AC magnetometry as a method to measure the specific absorption rate (SAR) of magnetic nanoparticles suitable for magnetic hyperthermia therapy. • We have built a lab-made AC magnetometer, which is able to measure magnetic dynamic hysteresis-loops of nanoparticle dispersions. • The device works with AC magnetic field intensities up to 24 kA m −1 in a frequency range from 75 kHz to 1 MHz. • The SAR values of maghemite nanoparticles around 12 nm in magnetic diameter dispersed in water are measured by the lab-made magnetometer and different calorimetric methods. • Although all methods are in good agreement, several factors (probe location, thermal inertia, losses, etc.) make calorimetric method less accurate than AC magnetometry

  6. Magnetic measurements of the injector synchrotron magnets for the Advanced Photon Source

    International Nuclear Information System (INIS)

    Kim, S.H.; Carnegie, D.W.; Doose, C.L.; Hogrefe, R.; Kim, K.; Merl, R.; Turner, L.R.

    1993-01-01

    The magnetic measurement data of the dipole, quadrupole, and sextupole magnets for the Advanced Photon Source injector synchrotron are summarized. Magnet design and magnetic measurements of the field strength, field shape, and multipole coefficients are described

  7. Magnetic measurements of the injector synchrotron magnets for the advanced photon source

    Science.gov (United States)

    Kim, S. H.; Carnegie, D. W.; Doose, C. L.; Hogrefe, R.; Kim, K.; Merl, R.; Turner, L. R.

    1994-07-01

    The magnetic measurement data of the dipole, quadrupole, and sextupole magnets for the Advanced Photon Source injector synchrotron are summarized. Magnet design and magnetic measurements of the field strength, field shape, and multipole coefficients are described.

  8. On the measurement of magnetic viscosity

    Science.gov (United States)

    Serletis, C.; Efthimiadis, K. G.

    2012-08-01

    This work is an investigation of the experimental method used for measuring the magnetic viscosity in a hard ferromagnetic material, i.e. the recording of the magnetization under constant applied field and temperature, after the material has been magnetically saturated. It investigates how the experimental results are affected by the initial conditions of the method (saturation field, field change rate and field oscillation prior to its stabilization), and by minor variations of field and temperature during the recording. Based on the arising conclusions and the use of a more complex fitting function of measurements, the accuracy and repeatability of experimental results is improved.

  9. 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.

  10. High temperature superconductor micro-superconducting-quantum-interference-device magnetometer for magnetization measurement of a microscale magnet.

    Science.gov (United States)

    Takeda, Keiji; Mori, Hatsumi; Yamaguchi, Akira; Ishimoto, Hidehiko; Nakamura, Takayoshi; Kuriki, Shinya; Hozumi, Toshiya; Ohkoshi, Shin-ichi

    2008-03-01

    We have developed a high temperature superconductor (HTS) micrometer-sized dc superconducting quantum interference device (SQUID) magnetometer for high field and high temperature operation. It was fabricated from YBa2Cu3O7-delta of 92 nm in thickness with photolithography techniques to have a hole of 4x9 microm2 and 2 microm wide grain boundary Josephson junctions. Combined with a three dimensional magnetic field coil system, the modulation patterns of critical current Ic were observed for three different field directions. They were successfully used to measure the magnetic properties of a molecular ferrimagnetic microcrystal (23x17x13 microm3), [Mn2(H2O)2(CH3COO)][W(CN)8]2H2O. The magnetization curve was obtained in magnetic field up to 0.12 T between 30 and 70 K. This is the first to measure the anisotropy of hysteresis curve in the field above 0.1 T with an accuracy of 10(-12) J T(-1) (10(-9) emu) with a HTS micro-SQUID magnetometer.

  11. Magnet Fiducialization with Coordinate Measuring Machines

    International Nuclear Information System (INIS)

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

    2005-01-01

    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--σ = ±30 (micro)m; mechanical centerline to fiducial marks--σ = ±50 (micro)m; and fiducial marks to adjacent components--σ = ±80 (micro)m; the TOTAL σ = ±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

  12. 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.

  13. MAGNETIC FIELD MEASUREMENTS FOR FAST-CHANGING MAGNETIC FIELDS

    International Nuclear Information System (INIS)

    2004-01-01

    Several recent applications for fast ramped magnets have been found that require rapid measurement of the field quality during the ramp. (In one instance, accelerator dipoles will be ramped at 1 T/sec, with measurements needed to the accuracy typically required for accelerators.) We have built and tested a new type of magnetic field measuring system to meet this need. The system consists of 16 stationary pickup windings mounted on a cylinder. The signals induced in the windings in a changing magnetic field are sampled and analyzed to obtain the field harmonics. To minimize costs, printed circuit boards were used for the pickup windings and a combination of amplifiers and ADPs used for the voltage readout system. New software was developed for the analysis. Magnetic field measurements of a model dipole developed for the SIS200 accelerator at GSI are presented. The measurements are needed to insure that eddy currents induced by the fast ramps do not impact the field quality needed for successful accelerator operation

  14. Crustal evolution inferred from apollo magnetic measurements

    International Nuclear Information System (INIS)

    Dyal, P.; Daily, W.D.; Vanyan, L.L.

    1978-09-01

    Magnetic field and solar wind plasma density measurements were analyzed to determine the scale size characteristics of remanent fields at the Apollo 12, 15, and 16 landing sites. Theoretical model calculations of the field-plasma interaction, involving diffusion of the remanent field into the solar plasma, were compared to the data. The information provided by all these experiments shows that remanent fields over most of the lunar surface are characterized by spatial variations as small as a few kilometers. Large regions (50 to 100 km) of the lunar crust were probably uniformly magnetized during early crustal evolution. Bombardment and subsequent gardening of the upper layers of these magnetized regions left randomly oriented, smaller scale (5 to 10 km) magnetic sources close to the surface. The larger scale size fields of magnitude approximately 0.1 gammas are measured by the orbiting subsatellite experiments and the small scale sized remanent fields of magnitude approximately 100 gammas are measured by the surface experiments

  15. The relationship between magnetisation and hysteresis of critical current in sintered YBCO. [Y-Ba-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    Jones, A R; Blunt, F J; Campbell, A M [Research Centre in Superconductivity, Univ. of Cambridge (United Kingdom); Doyle, R A [Dept. of Physics, Univ. of Witwatersrand (South Africa)

    1992-06-10

    Measurements are reported of transport critical current and magnetisation on the same samples of YBCO for three different orientations with respect to applied magnetic field. The predictions made by the model of Evetts and Glowacki for the hysteresis observed in J{sub c} were investigated and found to be in qualitative agreement with the results. However, attempts to relate the hysteresis to the magnetisation by assuming that J{sub c} is a unique function of the internal field H = H{sub 0}-nM were unsuccessful. The value of n is found to be much larger than any demagnetising factor and varies widely with both field and geometry. (orig.).

  16. Pressure measurements in magnetic-fusion devices

    International Nuclear Information System (INIS)

    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

  17. Measurement of gradient magnetic field temporal characteristics

    International Nuclear Information System (INIS)

    Bartusek, K.; Jflek, B.

    1994-01-01

    We describe a technique of measuring the time dependence and field distortions of magnetic fields due to eddy currents (EC) produced by time-dependent magnetic field gradients. The EC measuring technique makes use of a large volume sample and selective RF excitation pulses and free induction decay (FID) (or a spin or gradient echo) to measure the out-of-phase component of the FID, which is proportional to γδB, i.e. the amount the signal is off resonance. The measuring technique is sensitive, easy to implement and interpret, and used for determining pre-emphasis compensation parameters

  18. 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.

  19. Magnetic resonance: safety measures and biological effects

    International Nuclear Information System (INIS)

    Gordillo, I.; Lafuente, J.; Fernandez, C.; Barbero, M.J.; Cascon, E.

    1997-01-01

    The biological effects of electromagnetic fields is currently a subject of great controversy. For this reason, magnetic resonance imaging (MRI) and spectroscopy are constantly under investigation. The source of the risk in MRI is associated with the three types of electromagnetic radiation to which the patient is exposed: the static magnetic field, variable (gradient) magnetic fields and radiofrequency fields. Each is capable of producing significant biological effects when employed at sufficient intensity. Patients exposed to risk sources are those situated within the lines of force of the magnetic field, ellipsoid lines that are arranged around the magnet, representing the strength of the surrounding field. To date, at the intensity normally utilized in MRI(<2T) and respecting the field limit recommendations established by the US Food and Drug Administration (FDA) for clinical use of this technique no adverse secondary biological effects have been reported. The known biological effects and other possible secondary effects are reviewed, and the recommended safety measures are discussed. (Author)

  20. Magnetic Field Response Measurement Acquisition System

    Science.gov (United States)

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

    2007-01-01

    This paper presents a measurement acquisition method that alleviates many shortcomings of traditional measurement systems. The shortcomings are a finite number of measurement channels, weight penalty associated with measurements, electrical arcing, wire degradations due to wear or chemical decay and the logistics needed to add new sensors. Wire degradation has resulted in aircraft fatalities and critical space launches being delayed. The key to this method is the use of sensors designed as passive inductor-capacitor circuits that produce magnetic field responses. The response attributes correspond to states of physical properties for which the sensors measure. Power is wirelessly provided to the sensing element by using Faraday induction. A radio frequency antenna produces a time-varying magnetic field used to power the sensor and receive the magnetic field response of the sensor. An interrogation system for discerning changes in the sensor response frequency, resistance and amplitude has been developed and is presented herein. Multiple sensors can be interrogated using this method. The method eliminates the need for a data acquisition channel dedicated to each sensor. The method does not require the sensors to be near the acquisition hardware. Methods of developing magnetic field response sensors and the influence of key parameters on measurement acquisition are discussed. Examples of magnetic field response sensors and the respective measurement characterizations are presented. Implementation of this method on an aerospace system is discussed.

  1. Measurements of magnetic anisotropy in sickle cells

    International Nuclear Information System (INIS)

    Salvo Souza, L.H. de.

    1982-03-01

    Room temperature magnetic measurements in deoxigenated sickle cells showed the existence of magnetic anisotropy, Δchi=1,29 x 10 -3 . This effect was supposed paramagnetic and considered to be due to the iron atoms of the hemoglobin molecules which are one over the other, forming ordered chains inside the erythrocytes. Low temperature (liquid He - 4,2K) measurements of the magnetic anisotropy of sickle cells and normal red blood cells diluted in a cryoprotector was made to confirm the paramagnetic origin of the fenomena. For that purpose it was used a superconductor magnetometer coupled to a SQUID, developed in the 'Laboratorio do Estado Solido do Departamento de Fisica da PUC-RJ'. The results obtained seem to confirm the expected paramagnetic anisotropy and, furthermore, suggest the presence of magnetic interactions among the iron atoms in the sickle cells samples. (Author) [pt

  2. Device measures static friction of magnetic tape

    Science.gov (United States)

    Cole, P. T.

    1967-01-01

    Device measures the coefficient of static friction of magnetic tape over a range of temperatures and relative humidities. It uses a strain gage to measure the force of friction between a reference surface and the tape drawn at a constant velocity of approximately 0.0001 inch per second relative to the reference surface.

  3. Fabrication and magnetization measurement of Ni thin films on silicon substrate by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Tang Yang [Key Laboratory of Excited State Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China); Graduate School of the Chinese Academy of Sciences (China); Zhao Dongxu [Key Laboratory of Excited State Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China)], E-mail: dxzhao2000@yahoo.com.cn; Shen Dezhen; Zhang Jiying; Li Binghui; Lu Youming; Fan Xiwu [Key Laboratory of Excited State Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China)

    2008-02-29

    Ni thin films were electrodeposited on n-Si (100) substrate from the electrolytes containing Ni(CH{sub 3}COO){sub 2} and CH{sub 3}COONH{sub 4} at room temperature. The scanning electron microscope images of the films reveals the uniform distribution of the nickel all over the substrate surface, which illustrates that the fine Ni films on large scales could be obtained through the method of electrodeposition. Vibrating sample magnetometer measurement with the applied field parallel to the surface shows obvious hysteresis loops of the magnetic thin films. The morphology and magnetism of the Ni thin films evolves with the deposition time increasing. The effect of deposition conditions on the properties of the Ni thin films is investigated.

  4. Magnetic measurements on Tl-2212 and Bi-2212 single crystals: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Oussena, M. (Physics Dept., Univ. of Southampton (United Kingdom)); Porter, S. (Physics Dept., Univ. of Southampton (United Kingdom)); Volkozub, A. (Physics Dept., Univ. of Southampton (United Kingdom)); De Groot, P.A.J. (Physics Dept., Univ. of Southampton (United Kingdom)); Lanchester, P.C. (Physics Dept., Univ. of Southampton (United Kingdom)); Ogborne, D. (Physics Dept., Univ. of Southampton (United Kingdom) Chemistry Dept., Univ. of Southampton (United Kingdom)); Weller, M.T. (Physics Dept., Univ. of Southampton (United Kingdom) Chemistry Dept., Univ. of Southampton (United Kingdom)); Balakrishnan, G. (Physics Dept., Univ. of Southampton (United Kingdom) Physics Dept., Univ. of Warwick, Coventry (United Kingdom)); Paul, D.McK. (Physics Dept., Univ. of Southampton (United Kingdom) Physics Dept., Univ. of Warwick, Coventry (United Kingdom))

    1994-02-01

    We have compared the magnetic behaviour of two identically shaped single crystals, Tl[sub 2]Ba[sub 2]CaCu[sub 2]O[sub 8] and Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8]. The critical current density is found to decrease more rapidly with temperature in Bi-2212 although it is the highest in this material at low temperatures (T < 10K). I-V characteristic curves have been obtained from measurements of magnetic sweep rate dependencies of the hysteresis loops. We have found that the characteristic temperature at which flux motion becomes important is significantly higher in Tl-2212 than in Bi-2212. Hence the Tl-2212 has a larger effective pinning. (orig.)

  5. Magnetic measurements on Tl-2212 and Bi-2212 single crystals: a comparative study

    International Nuclear Information System (INIS)

    Oussena, M.; Porter, S.; Volkozub, A.; De Groot, P.A.J.; Lanchester, P.C.; Ogborne, D.; Weller, M.T.; Balakrishnan, G.; Paul, D.McK.

    1994-01-01

    We have compared the magnetic behaviour of two identically shaped single crystals, Tl 2 Ba 2 CaCu 2 O 8 and Bi 2 Sr 2 CaCu 2 O 8 . The critical current density is found to decrease more rapidly with temperature in Bi-2212 although it is the highest in this material at low temperatures (T < 10K). I-V characteristic curves have been obtained from measurements of magnetic sweep rate dependencies of the hysteresis loops. We have found that the characteristic temperature at which flux motion becomes important is significantly higher in Tl-2212 than in Bi-2212. Hence the Tl-2212 has a larger effective pinning. (orig.)

  6. CIME: last results of magnetic measurements

    International Nuclear Information System (INIS)

    Duval, M.

    1997-01-01

    This paper reports about the magnetic measurements recently finished at the CIME cyclotron. The measurements were carried out over two stages, first in January 1997 dedicated to the magnetic chart acquisition (for the main field only) and the other from 16 April to 2 June dedicated to the chart acquisition of the isochronous fields (main field + 11 correction magnetic coils). These charts have a closed enough meshing to ensure good interpolations and to define the current intensity values for any working point. This has been tested by measuring the fields calculated for a 18 O +4 beam. The results confirmed all the calculations done with TOSCA code. Calculations of current intensities for 11 isochronous coils were made by using only field response given by TOSCA for each coil and each induction level. (author)

  7. The significance of vector magnetic field measurements

    Science.gov (United States)

    Hagyard, M. J.

    1990-01-01

    Observations of four flaring solar active regions, obtained during 1980-1986 with the NASA Marshall vector magnetograph (Hagyard et al., 1982 and 1985), are presented graphically and characterized in detail, with reference to nearly simultaneous Big Bear Solar Observatory and USAF ASW H-alpha images. It is shown that the flares occurred where local photospheric magnetic fields differed most from the potential field, with initial brightening on either side of a magnetic-neutral line near the point of maximum angular shear (rather than that of maximum magnetic-field strength, typically 1 kG or greater). Particular emphasis is placed on the fact that these significant nonpotential features were detected only by measuring all three components of the vector magnetic field.

  8. On the measurement of magnetic viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Serletis, C. [Department of Physics, Aristotle University, Thessaloniki 54124 (Greece); Efthimiadis, K.G., E-mail: kge@auth.gr [Department of Physics, Aristotle University, Thessaloniki 54124 (Greece)

    2012-08-15

    This work is an investigation of the experimental method used for measuring the magnetic viscosity in a hard ferromagnetic material, i.e. the recording of the magnetization under constant applied field and temperature, after the material has been magnetically saturated. It investigates how the experimental results are affected by the initial conditions of the method (saturation field, field change rate and field oscillation prior to its stabilization), and by minor variations of field and temperature during the recording. Based on the arising conclusions and the use of a more complex fitting function of measurements, the accuracy and repeatability of experimental results is improved. - Highlights: Black-Right-Pointing-Pointer Magnetic viscosity is affected by initial measurement conditions. Black-Right-Pointing-Pointer Minor field deviations prior to its stabilization cause large changes in viscosity. Black-Right-Pointing-Pointer Viscosity is strongly dependent on the field change rate from saturation to the measurement field. Black-Right-Pointing-Pointer Small changes in field and temperature during the experiment can lead to false measurements. Black-Right-Pointing-Pointer Errors in measurements can be eliminated through the use of a proper fitting function.

  9. Absolute method of measuring magnetic susceptibility

    Science.gov (United States)

    Thorpe, A.; Senftle, F.E.

    1959-01-01

    An absolute method of standardization and measurement of the magnetic susceptibility of small samples is presented which can be applied to most techniques based on the Faraday method. The fact that the susceptibility is a function of the area under the curve of sample displacement versus distance of the magnet from the sample, offers a simple method of measuring the susceptibility without recourse to a standard sample. Typical results on a few substances are compared with reported values, and an error of less than 2% can be achieved. ?? 1959 The American Institute of Physics.

  10. Magnetic susceptibility as a direct measure of oxidation state in LiFePO4 batteries and cyclic water gas shift reactors.

    Science.gov (United States)

    Kadyk, Thomas; Eikerling, Michael

    2015-08-14

    The possibility of correlating the magnetic susceptibility to the oxidation state of the porous active mass in a chemical or electrochemical reactor was analyzed. The magnetic permeability was calculated using a hierarchical model of the reactor. This model was applied to two practical examples: LiFePO4 batteries, in which the oxidation state corresponds with the state-of-charge, and cyclic water gas shift reactors, in which the oxidation state corresponds to the depletion of the catalyst. In LiFePO4 batteries phase separation of the lithiated and delithiated phases in the LiFePO4 particles in the positive electrode gives rise to a hysteresis effect, i.e. the magnetic permeability depends on the history of the electrode. During fast charge or discharge, non-uniform lithium distributionin the electrode decreases the hysteresis effect. However, the overall sensitivity of the magnetic response to the state-of-charge lies in the range of 0.03%, which makes practical measurement challenging. In cyclic water gas shift reactors, the sensitivity is 4 orders of magnitude higher and without phase separation, no hysteresis occurs. This shows that the method is suitable for such reactors, in which large changes of the magnetic permeability of the active material occurs.

  11. On the influence of thermal hysteresis on the performance of thermomagnetic motors

    Science.gov (United States)

    Bessa, C. V. X.; Ferreira, L. D. R.; Horikawa, O.; Monteiro, J. C. B.; Gandra, F. G.; Gama, S.

    2017-12-01

    Although thermal hysteresis might be a problem in the magnetocaloric refrigeration, the same is not necessarily true for thermomagnetic motor applications. This work presents a comparison of the magnetocaloric properties of materials with first order magnetic transition (having large or narrow thermal hysteresis) to those with second order magnetic transition, assessing the application of these materials in thermomagnetic motors through a thermodynamic approach. Results show that the larger the thermal hysteresis, the higher the specific work produced in a thermal cycle. This allows operation at higher temperature differences with high efficiency relative to Carnot efficiency, when compared with systems using narrow hysteresis and second order transition materials.

  12. Modelling of hysteresis in thin superconducting screens for mixed-mu suspension systems

    International Nuclear Information System (INIS)

    Asher, G.M.; Williams, J.T.; Walters, C.R.; Joyce, H.; Paul, R.J.A.

    1982-01-01

    Mixed-mu levitation is the principle whereby iron is levitated in a magnetic field and stabilized by the proximity of diamagnetic superconducting screens. In a dynamic environment, the screens are subject to changing magnetic fields thus causing hysteresis losses in the superconducting material. This paper is concerned with the modeling of such hysteresis. A finite difference approximation to the current and field distributions is employed, the current distribution being made consistent with critical current values by iteration. Square and disc shaped screen samples are studied and hysteresis curves computed. It is shown that the method represents a fair approximation to the hysteresis behavior of thin superconducting screens. 8 refs

  13. Efficient modeling of vector hysteresis using fuzzy inference systems

    International Nuclear Information System (INIS)

    Adly, A.A.; Abd-El-Hafiz, S.K.

    2008-01-01

    Vector hysteresis models have always been regarded as important tools to determine which multi-dimensional magnetic field-media interactions may be predicted. In the past, considerable efforts have been focused on mathematical modeling methodologies of vector hysteresis. This paper presents an efficient approach based upon fuzzy inference systems for modeling vector hysteresis. Computational efficiency of the proposed approach stems from the fact that the basic non-local memory Preisach-type hysteresis model is approximated by a local memory model. The proposed computational low-cost methodology can be easily integrated in field calculation packages involving massive multi-dimensional discretizations. Details of the modeling methodology and its experimental testing are presented

  14. Implementation and identification of Preisach type hysteresis models with Everett Function in closed form

    Energy Technology Data Exchange (ETDEWEB)

    Szabó, Zsolt, E-mail: szabo@evt.bme.hu [Department of Broadband Infocommunications and Electromagnetic Theory, Budapest University of Technology and Economics, Budapest (Hungary); Füzi, János [Neutron Spectroscopy Department, Wigner Research Centre for Physics, Budapest (Hungary); Faculty of Engineering and Information Technology, University of Pécs (Hungary)

    2016-05-15

    The Preisach function is considered as a product of two special one dimensional functions, which allows the closed form evaluation of the Everett integral. The deduced closed form expressions are included in Preisach models, in particular in the static model, moving model and a rate dependent hysteresis model, which can simulate the frequency dependence of the magnetization process. The details of the freely available implementations, which are available online are presented. The identification of the model parameters and the accuracy to describe the magnetization process are discussed and demonstrated by fitting measured data. Transient electric circuit simulation with hysteresis demonstrates the applicability of the developed models. - Highlights: • Formulation of the Preisach model with Everett function in closed form. • Identification of the parameters: when the shape of the analytical Preisach function does not matches the ferromagnetic material the moving model can be applied to increase the accuracy. • Novel algorithm with Fixed Point iteration, which utilizes the closed formulation to simulate the frequency dependence of the magnetization process. • The developed hysteresis models are utilized in circuit simulation algorithm to determine the transient behavior of the current, which flows through a toroidal coil with ferromagnetic core.

  15. Investigation of scaling laws in frequency-dependent minor hysteresis loops for ferromagnetic steels

    International Nuclear Information System (INIS)

    Kobayashi, S.; Tsukidate, S.; Kamada, Y.; Kikuchi, H.; Ohtani, T.

    2012-01-01

    Scaling laws in dynamical magnetic minor hysteresis loops have been investigated in the magnetizing frequency range of 0.05-300 Hz for various steels including Cr-Mo-V steel subjected to creep, cold rolled steels, and plastically deformed Ni. Although scaling laws in the medium magnetization range found previously fail in the high magnetization frequency regime owing to a significant contribution of eddy currents, a scaling power law of the relation between remanence and remanence work of minor loops, associated with a constant exponent of approximately 1.9, holds true in a very low magnetization regime, irrespective of magnetization frequency and investigated materials. The coefficient of the law is proportionally related to Vickers hardness over the wide frequency range. These observations demonstrate that the scaling analysis of dynamical minor loops enables us to evaluate materials degradation in a short measurement time with low measurement field and high sensitivity to defect density. - Highlights: → We performed hysteresis scaling for dynamical minor loops in ferromagnetic steels. → An universal scaling power law with an exponent of 1.9 was observed. → Coefficient of the scaling law reflects defect density due to creep and deformation. → This method is useful for on-line non-destructive evaluation.

  16. Mechanical equipment for magnet measurement and alignment

    International Nuclear Information System (INIS)

    Harvey, A.

    1992-05-01

    The mechanical equipment for measuring and aligning (or fiducializing) magnets is described by reference to devices designed and built by a number of laboratories. Some of these are now available commercially. The descriptions are supplemented by a list of representative sources of hardware

  17. Multichannel simultaneous magnetic induction measurement system (MUSIMITOS)

    International Nuclear Information System (INIS)

    Steffen, Matthias; Leonhardt, Steffen; Heimann, Konrad; Bernstein, Nina

    2008-01-01

    Non-contact heart and lung activity monitoring would be a desirable supplement to conventional monitoring techniques. Based on the potential of non-contact magnetic induction measurements, requirements for an adequate monitoring system were estimated. This formed the basis for the development of the presented extendable multichannel simultaneous magnetic induction measurement system (MUSIMITOS). Special focus was given to the dynamic behaviour and simultaneous multichannel measurements, so that the system allows for up to 14 receiver coils working simultaneously at 6 excitation frequencies. Moreover, a real-time software concept for online signal processing visualization in combination with a fast software demodulation is presented. Finally, first steps towards a clinical application are pointed out and technical performance as well as first in vivo measurements are presented. This paper covers some aspects previously presented in Steffen and Leonhardt (2007 Proc. 13th Int. Conf. on Electrical Bioimpedance and the 8th Conf. on Electrical Impedance Tomography, Graz 2007)

  18. Measurement accuracy in shielded magnetic fields

    International Nuclear Information System (INIS)

    Bottauscio, Oriano; Chiampi, Mario; Crotti, Gabriella; Zucca, Mauro

    2005-01-01

    The measurement error due to both the probe size averaging effect and the coil arrangement is investigated when magnetic field measurements are performed in close proximity to different planar shields. The analysis is carried on through a hybrid FEM/BEM model which employs the 'thin shield' technique. Ferromagnetic, pure conductive and multilayer screens are taken into consideration and an estimation of the errors for concentric and non-concentric coil probes is given. The numerical results are validated by experiments

  19. Magnetic field measurements in xi Bootis A

    International Nuclear Information System (INIS)

    Boesgaard, A.M.; Chesley, D.; Preston, G.W.

    1975-01-01

    Four Zeeman spectrograms from Lick Observatory of xi Boo A and two of iota Peg at 2 A mm -1 have been measured to determine if a weak magnetic field is present in xi Boo A. The results indicate that the field is too weak to be measured by this technique on these spectrograms, although remeasurements of spectrograms from Mauna Kea at 3.4 A mm -1 still give a positive field of 170 gauss. (U.S.)

  20. Precise NMR measurement and stabilization system of magnetic field of a superconducting 7 T wave length shifter

    CERN Document Server

    Borovikov, V M; Karpov, G V; Korshunov, D A; Kuper, E A; Kuzin, M V; Mamkin, V R; Medvedko, A S; Mezentsev, N A; Repkov, V V; Shkaruba, V A; Shubin, E I; Veremeenko, V F

    2001-01-01

    The system of measurement and stabilization of the magnetic field in the superconducting 7 T wave length shifter (WLS), designed at Budker Institute of Nuclear Physics are described. The measurements are performed by nuclear magnetic resonance (NMR) magnetometer at two points of the WLS magnetic field. Stabilization of the field is provided by the current pumping system. The stabilization system is based on precise NMR measurement of magnetic field as a feedback signal for computer code which control currents inside the superconducting coils. The problem of the magnetic field measurements with NMR method consists in wide spread of field in the measured area (up to 50 Gs/mm), wide temperature range of WLS operating, small space for probe and influence of iron hysteresis. Special solid-state probes were designed to satisfy this requirements. The accuracy of magnetic field measurements at probe locations is not worse than 20 ppm. For the WLS field of 7 T the reproducibility of the magnetic field of 30 ppm has be...

  1. Theoretical approach to the magnetocaloric effect with hysteresis

    International Nuclear Information System (INIS)

    Basso, V.; Bertotti, G.; LoBue, M.; Sasso, C.P.

    2005-01-01

    In this paper a thermodynamic model with internal variables is presented and applied to ferromagnetic hysteresis. The out-of-equilibrium Gibbs free energy of a magnetic system is expressed as a function of the internal state of the Preisach model. Expressions for the system entropy and the entropy production are derived. By this approach it is possible to reproduce the characteristic features of the experimentally observed temperature changes (of the order of 10 -4 K around room temperature) induced by the magnetic field along the hysteresis loop performed in iron under adiabatic condition

  2. Hysteresis Bearingless Slice Motors with Homopolar Flux-biasing.

    Science.gov (United States)

    Noh, Minkyun; Gruber, Wolfgang; Trumper, David L

    2017-10-01

    We present a new concept of bearingless slice motor that levitates and rotates a ring-shaped solid rotor. The rotor is made of a semi-hard magnetic material exhibiting magnetic hysteresis, such as D2 steel. The rotor is radially biased with a homopolar permanent-magnetic flux, on which the stator can superimpose 2-pole flux to generate suspension forces. By regulating the suspension forces based on position feedback, the two radial rotor degrees of freedom are actively stabilized. The two tilting degrees of freedom and the axial translation are passively stable due to the reluctance forces from the bias flux. In addition, the stator can generate a torque by superimposing 6- pole rotating flux, which drags the rotor via hysteresis coupling. This 6-pole flux does not generate radial forces in conjunction with the homopolar flux or 2-pole flux, and therefore the suspension force generation is in principle decoupled from the driving torque generation. We have developed a prototype system as a proof of concept. The stator has twelve teeth, each of which has a single phase winding that is individually driven by a linear transconductance power amplifier. The system has four reflective-type optical sensors to differentially measure the two radial degrees of freedom of the rotor. The suspension control loop is implemented such that the phase margin is 25 degrees at the cross-over frequency of 110 Hz. The prototype system can levitate the rotor and drive it up to about 1730 rpm. The maximum driving torque is about 2.7 mNm.

  3. Field measuring probe for SSC magnets

    International Nuclear Information System (INIS)

    Ganetis, G.; Herrera, J.; Hogue, R.; Skaritka, J.; Wanderer, P.; Willen, E.

    1987-01-01

    The field probe developed for measuring the field in SSC dipole magnets is an adaptation of the rotating tangential coil system in use at Brookhaven for several years. Also known as the MOLE, it is a self-contained room-temperature mechanism that is pulled through the aperture of the magnet with regular stops to measure the local field. Several minutes are required to measure the field at each point. The probe measures the multipole components of the field as well as the field angle relative to gravity. The sensitivity of the coil and electronics is such that the field up to the full 6.6 T excitation of the magnet as well as the field when warm with only 0.01 T excitation can be measured. Tethers are attached to both ends of the probe to carry electrical connections and to supply dry nitrogen to the air motors that rotate the tangential windings as well as the gravity sensor. A small computer is attached to the probe for control and for data collection, analysis and storage

  4. Test Station for Magnetization Measurements on Large Quantities of Superconducting Strands

    CERN Document Server

    Le Naour, S; Billan, J; Genest, J

    2001-01-01

    In the superconducting main magnets of the Large Hadron Collider (LHC), persistent currents in the superconductor determine the field quality at injection field. For this reason it is necessary to check the magnetization of the cable strands during their production. During four years, this requires measurements of the width of the strand magnetization hysteresis loop at 0.5 T, 1.9 K, at a rate of up to eight samples per day. This paper describes the design, construction and the first results of a magnetization test station built for this purpose. The samples are cooled in a cryostat, with a 2-m long elliptic tail. This tail is inserted in a normal conducting dipole magnet with a field between ± 1.5 T. Racetrack pick-up coils, integrated in the cryostat, detect the voltage due to flux change, which is then integrated numerically. The sample holder can contain eight strand samples, each 20 cm long. The test station operates in two modes: either the sample is fixed while the external field is changed, or the sa...

  5. Magnetism variations and susceptibility hysteresis at the metal-insulator phase transition temperature of VO2 in a composite film containing vanadium and tungsten oxides

    CSIR Research Space (South Africa)

    Akande, AA

    2015-02-01

    Full Text Available We report on the magnetic property of 0.67–WO3+0.33–VOx mixture film deposit on the corning glass substrate using the chemical sol–gel and atmospheric pressure chemical vapour deposition (APCVD) methods. The XRD and Raman spectroscopy confirm...

  6. 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.

  7. Review of MFTF yin-yang magnet displacement and magnetic field measurements and calculations

    International Nuclear Information System (INIS)

    Hanson, C.L.; Myall, J.O.; Wohlwend, J.W.

    1983-01-01

    During the recent testing of the MFTF yin-yang magnet, measurements of coil position, structural case strain, and magnetic field were made to verify calculated values. Measurements to detect magnet movement were taken throughout cooldown and during the operation of the magnet. The magnetic field at the mirror points was measured by Hall-effect probes. The magnet position, structural case strain, and magnetic field measurements indicated a reasonably close correlation with calculated values. Information obtained from the yin-yang test has been very useful in setting realistic mechanical alignment values for the new MFTF-B magnet system

  8. The magnet measurement facility for the Advanced Photon Source

    International Nuclear Information System (INIS)

    Kim, S.H.; Doose, C.; Hogrefe, R.; Kim, K.; Merl, R.

    1993-01-01

    A magnet measurement facility has been developed to measure the prototype and production magnets for the Advance Photon Source. The measurement facility is semi-automatic in measurement control and data analysis. One dipole system and three rotating coil measurement systems for quadrupole and sextupole magnets and corresponding probe coils are described

  9. Field measurement of dipole magnets for TARN

    International Nuclear Information System (INIS)

    Hori, T.; Noda, A.; Hattori, T.; Fujino, T.; Yoshizawa, M.

    1980-05-01

    Eight dipole magnets of window-frame type with zero field gradient have been fabricated for TARN. Various characteristics of the field were examined by a measuring system with a Hall and an NMR probes. The accuracy of the measurement was better than 1 x 10 -4 at the maximum field strength of --9 kG, and the uniformity of the field in the radial direction was better than +-2 x 10 -4 over the whole useful aperture. The deviations both of the field strengths and of the effective lengths among the eight magnets are smaller than +-2 x 10 -3 . The sextupole component of the field and the variation of the effective length over the beam orbits contribute to chromaticities of the ring as the amount of -1.59 and 0.93 in the horizontal and vertical directions, respectively. (author)

  10. Magnetization measurements of a novel family of heteronuclear Mn{sub 2}Ni{sub 3} SMM clusters

    Energy Technology Data Exchange (ETDEWEB)

    Gieb, Klaus; Kroener, Wolfgang; Mueller, Paul [Department of Physics and Interdisciplinary Center for Molecular Materials (ICMM), Universitaet Erlangen-Nuernberg (Germany); Das, Animesh; Demeshko, Serhiy; Meyer, Franc [Institut fuer Anorganische Chemie, Georg-August-Universitaet Goettingen (Germany); Krupskaya, Yulia; Klingeler, Ruediger; Kataev, Vladislav; Buechner, Bernd [Leibniz-Institute for Solid State and Materials Research IFW Dresden (Germany)

    2010-07-01

    We report on magnetic measurements of two heterometallic Mn{sup III}{sub 2}Ni{sup II}{sub 3}X{sub 2}L{sub 4}(LH){sub 2}(H2O){sub 2} (X=Cl, Br) complexes. These compounds have a ground state spin of S=7 and show an easy-axis type of anisotropy. DC and AC susceptibility measurements were performed with a commercial SQUID magnetometer. A home-made micro-Hall-probe magnetometer was used to perform the characterization at mK temperatures. We found an uniaxial anisotropy parameter of D{approx_equal}-0.5 K. Magnetic hysteresis and quantum tunneling of magnetization was observed at temperatures below a blocking temperature T{sub B}{approx_equal}1.5 K. The shape of the hysteresis loop is influenced by intermolecular interactions. The signature of these interactions can be modified by the variation of the Mn coordination partner X.

  11. 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...

  12. Data-driven techniques to estimate parameters in a rate-dependent ferromagnetic hysteresis model

    International Nuclear Information System (INIS)

    Hu Zhengzheng; Smith, Ralph C.; Ernstberger, Jon M.

    2012-01-01

    The quantification of rate-dependent ferromagnetic hysteresis is important in a range of applications including high speed milling using Terfenol-D actuators. There exist a variety of frameworks for characterizing rate-dependent hysteresis including the magnetic model in Ref. , the homogenized energy framework, Preisach formulations that accommodate after-effects, and Prandtl-Ishlinskii models. A critical issue when using any of these models to characterize physical devices concerns the efficient estimation of model parameters through least squares data fits. A crux of this issue is the determination of initial parameter estimates based on easily measured attributes of the data. In this paper, we present data-driven techniques to efficiently and robustly estimate parameters in the homogenized energy model. This framework was chosen due to its physical basis and its applicability to ferroelectric, ferromagnetic and ferroelastic materials.

  13. Single molecule magnets from magnetic building blocks

    Science.gov (United States)

    Kroener, W.; Paretzki, A.; Cervetti, C.; Hohloch, S.; Rauschenbach, S.; Kern, K.; Dressel, M.; Bogani, L.; M&üLler, P.

    2013-03-01

    We provide a basic set of magnetic building blocks that can be rationally assembled, similar to magnetic LEGO bricks, in order to create a huge variety of magnetic behavior. Using rare-earth centers and multipyridine ligands, fine-tuning of intra and intermolecular exchange interaction is demonstrated. We have investigated a series of molecules with monomeric, dimeric and trimeric lanthanide centers using SQUID susceptometry and Hall bar magnetometry. A home-made micro-Hall-probe magnetometer was used to measure magnetic hysteresis loops at mK temperatures and fields up to 17 T. All compounds show hysteresis below blocking temperatures of 3 to 4 K. The correlation of the assembly of the building blocks with the magnetic properties will be discussed.

  14. Finding the magnetic size distribution of magnetic nanoparticles from magnetization measurements via the iterative Kaczmarz algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Daniel, E-mail: frank.wiekhorst@ptb.de; Eberbeck, Dietmar; Steinhoff, Uwe; Wiekhorst, Frank

    2017-06-01

    The characterization of the size distribution of magnetic nanoparticles is an important step for the evaluation of their suitability for many different applications like magnetic hyperthermia, drug targeting or Magnetic Particle Imaging. We present a new method based on the iterative Kaczmarz algorithm that enables the reconstruction of the size distribution from magnetization measurements without a priori knowledge of the distribution form. We show in simulations that the method is capable of very exact reconstructions of a given size distribution and, in that, is highly robust to noise contamination. Moreover, we applied the method on the well characterized FeraSpin™ series and obtained results that were in accordance with literature and boundary conditions based on their synthesis via separation of the original suspension FeraSpin R. It is therefore concluded that this method is a powerful and intuitive tool for reconstructing particle size distributions from magnetization measurements. - Highlights: • A new method for the size distribution fit of magnetic nanoparticles is proposed. • Employed Kaczmarz algorithm does not need a priori input or eigenwert regularization. • The method is highly robust to noise contamination. • Size distributions are reconstructed from simulated and measured magnetization curves.

  15. Magnetic field measurement in the analyzing magnet of NIS spectrometer

    Science.gov (United States)

    Avramenko, S. A.; Afanas'ev, S. V.; Voloshina, I. G.; Dolgii, S. A.; Yusupov, A. Yu.; Kalmykov, A. V.; Makoveev, V. K.; Nikolaevskii, G. P.; Ostrovskii, I. V.; Perepelkin, E. E.; Peresedov, V. F.; Plyashkevich, S. N.; Rossiiskaya, N. S.; Salmin, R. A.; Spodarets, V. K.; Strokovskii, E. A.; Yudin, I. P.

    2006-12-01

    The main goals of the Nucleon Intrinsic Strangeness experiment (NIS) are the search for the effects of hidden polarized strangeness in the nucleon and the exploration and study of exotic baryons (pentaquarks) in NN reactions. The setup is located in the Laboratory of High Energies at the Joint Institute for Nuclear Research in channel 4V of the Nuclotron extracted beam with the energy between 1 and 4 GeV. The 1SP-40-4V electromagnet of the spectrometer has the external dimensions 3.20 × 3.26 × 4.48 m and the aperture 2.74 × 0.68 m. The magnetic field measurement was performed using the three-component Hall magnetometer in the computer-controlled automated mode. The volume of measurements was 1.03 × 0.60 × 3.92 m. The description of the measuring equipment and measurement procedure is given. The results of the measurements are used for the Monte Carlo computer modeling of the experiment. These results will be used in the analysis of physical data after their acquisition.

  16. Evaluation of the magnetic and mechanical properties of reactor pressure vessel steels by incremental permeability change curve measurements

    International Nuclear Information System (INIS)

    Ebine, N.; Suzuki, M.

    2001-01-01

    Incremental permeability measurement was performed for two types of structural steels along with the magnetization of their hysteresis minor-loop. The obtained incremental permeability change curve has two sharp peaks, and the width between the two peaks is correlated with the coercivity. Hence the existence of good correlation was verified. On the basis of this result, nondestructive measurement experiments were carried out with planar coils to evaluate changes in the material properties of ferromagnetic structural steel plates. Changes in output voltages from planar coils with different test plates were correlated with their mechanical and magnetic properties. The correlation is so good that the measurement method adopted in this work could be used for nondestructive evaluation of material degradation in ferromagnetic structural steels. (author)

  17. Hysteresis properties of conventionally annealed and Joule-heated nanocrystalline Fe73.5Cu1Nb3Si13.5B9 alloys

    International Nuclear Information System (INIS)

    Tiberto, P.; Basso, V.; Beatrice, C.; Bertotti, G.

    1996-01-01

    The dependence of magnetic properties on the thermal treatment used to induce the amorphous-to-nanocrystalline transformation in Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 alloy has been studied. Quasi-static hysteresis loops and initial permeability measurements were performed on nanocrystalline samples obtained by conventional annealing and Joule heating. A comparison between the magnetic properties of nanocrystalline samples obtained by the two heating procedures is presented. (orig.)

  18. Creeping of hysteresis cycles; Reptation des cycles d'hysteresis

    Energy Technology Data Exchange (ETDEWEB)

    Neel, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Faculte des Sciences de Grenoble, 38 (France)

    1959-07-01

    Creeping consists of a kind of progressive translation of dissymmetric ferromagnetic hysteresis cycles as a function of the order number of the cycle. It is interpreted here by means of a probable coupling field, the existence of which is connected to a statistical conception of the distribution of the elementary regions. (author) [French] La reptation consiste en une sorte de translation progressive des cycles d'hysteresis ferromagnetiques dissymetriques en fonction du numero d'ordre du cycle. L'auteur l'interprete au moyen d'un champ aleatoire de couplage dont l'existence est liee a une conception statistique de la distribution des domaines elementaires. (auteur)

  19. Warm magnetic measurements of MCBCs: comparison between the results obtained with the Quadrupole Industrial Magnetic Measurement and the Corrector Industrial Magnetic Measurement systems

    CERN Document Server

    Remondino, Vittorio; Catalan-Lasheras, N

    2005-01-01

    MCBCs modules are first magnetically measured at Tesla using a second-generation Corrector Industrial Magnetic Measurement (CIMM). After assembly into the SSS quadrupoles, measurements are repeated at CERN using the Quadrupole Industrial Magnetic Measurement (QIMM) system. In this note, we compare the measurements provided by the two systems. In all the 18 cases examined, the correlation found is excellent. The consistency of the results obtained indicates that both systems are effective, that modules are correctly measured by the firm personnel and that magnetic characteristics of the modules do not change during their assembly in cold masses.

  20. Review of MFTF yin-yang magnet displacement and magnetic field measurements and calculations

    International Nuclear Information System (INIS)

    Hanson, C.L.; Myall, J.O.; Wohlwend, J.W.

    1983-01-01

    During the recent testing of the MFTF yin-yang magnet, measurements of coil position, structural case strain, and magnetic field were made to verify calculated values. Measurements to detect magnet movement were taken throughout cooldown and during the operation of the magnet. The magnetic field at the mirror points was measured by Hall-effect probes. The magnet position, structural case strain, and magntic field measurements indicated a reasonably close correlation with calculated values. Information obtained from the yin-yang test has been very useful in setting realistic mechanical alignment values for the new MFTF-B magnet system

  1. Development of a magnetic measurement device for thin ribbon samples

    International Nuclear Information System (INIS)

    Sato, Yuta; Todaka, Takashi; Enokizono, Masato

    2008-01-01

    This paper presents a magnetic measurement device for thin ribbon samples, which are produced by rapid cooling technique. This device enables us to measure magnetic properties easily by only inserting a ribbon sample into a sample holder. The sample holder was made by bakelite to fix any width sample. A long solenoid coil was used to generate a uniform magnetic field and the sample holder was placed at the mid part of the solenoid. The magnetic field strength was measured using a shunt resistor and the magnetic flux density and magnetization in sample ribbons were evaluated by using search coils. The accuracy of measurement was verified with an amorphous metal ribbon sample. Next, we have measured magnetic properties of some magnetic shape memory alloys, which have different compositions. The measured results are compared and we clarified the effect of Sm contents on the magnetic properties

  2. Magnetic field measuring system for remapping the ORIC magnetic field

    International Nuclear Information System (INIS)

    Mosko, S.W.; Hudson, E.D.; Lord, R.S.; Hensley, D.C.; Biggerstaff, J.A.

    1977-01-01

    The Holifield Heavy Ion Research Facility will integrate a new 25 MV tandem electrostatic acccelerator into the existing cyclotron laboratory which includes the Oak Ridge Isochronous Cyclotron (ORIC). Computations of ion paths for beam injection from the new tandem into ORIC require field mapping in the regions traversed by the beam. Additional field data is also desired for the higher levels (approx.19 kG) now used for most heavy ion beams. The magnetic field measurement system uses 39 flip coil/current integrator sets with computer controlled data scanning. The coils are spaced radially at 1 inch intervals in an arm which can be rotated azimuthally in 2 degree increments. The entire flip coil assembly can be shifted to larger radii to measure fields beyond the pole boundary. Temperature stabilization of electronic circuitry permits a measurement resolution of +-1 gauss over a dynamic range of +-25,000 gauss. The system will process a scan of 8000 points in about one hour

  3. Biodegradation of magnetic nanoparticles evaluated from Moessbauer and magnetization measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mischenko, I., E-mail: IlyaMischenko@rambler.ru; Chuev, M. [Russian Academy of Sciences, Institute of Physics and Technology (Russian Federation); Cherepanov, V.; Polikarpov, M.; Panchenko, V. [National Research Centre ' Kurchatov Institute' (Russian Federation)

    2013-04-15

    In order to extract a quantitative information about characteristics of the magnetic nanoparticles injected into a living organism it is necessary to define a model of the magnetic dynamics for fitting self-consistently the whole set of the experimental data, specifically, the evolution of Moessbauer spectral shape with temperature and external magnetic field as well as the magnetization curves. We have developed such a model and performed such an analysis of the temperature- and magnetic field-dependent spectra and magnetization curves of nanoparticles injected into mice. This allowed us to reliably evaluate changes in the characteristics of the residual particles and their chemical transformation to paramagnetic ferritin-like forms in different mouse organs as a function of time. Actually, the approach makes it possible to quantitatively characterize biodegradation and biotransformation of magnetic nanoparticles delivered in a body.

  4. Fluxgate Magnetic Sensor and Its Application for Current Measurement

    International Nuclear Information System (INIS)

    Mitra-Djamal

    2007-01-01

    Conventionally electric current can be measured by connecting the instrument serially on the circuit. This method has disadvantage because its disturb the measured current flow. By using a magnetic sensor, current can be measured without disturbing the current flow, because it just measures the magnetic field of the measured current. This paper shows the use of fluxgate magnetic sensor for current measurement. It is shown that the sensor can measure widely range of current with resolution ≤ 2 %. (author)

  5. Field measurement for large bending magnets

    International Nuclear Information System (INIS)

    Lazzaro, A.; Cappuzzello, F.; Cunsolo, A.; Cavallaro, M.; Foti, A.; Orrigo, S.E.A.; Rodrigues, M.R.D.; Winfield, J.S.

    2008-01-01

    The results of magnetic field measurements of the large bending magnet of the MAGNEX spectrometer are presented. The experimental values are used to build an Enge function by the least-squares method. The resulting field is compared to the measured one, showing too large deviation for application to ray reconstruction techniques. Similarly, the experimental values are compared with results from a three-dimensional finite elements calculation. Again the deviations between measured and calculated field are too large for a direct application of the latter to ray reconstruction, while its reliability is sufficient for analysis purposes. In particular, it has been applied to study the effect of the inaccuracies in the probe location and orientation on the precision of field reconstruction, and to establish the requirements for the field interpolation. These inaccuracies are found to be rather important, especially for the transversal components of the field, with the consequence that their effect on the reconstructed field should be minimized by special interpolation algorithms

  6. Planar permanent magnet multipoles: Measurements and configurations

    International Nuclear Information System (INIS)

    Cremer, T.; Tatchyn, R.

    1995-05-01

    Biplanar arrays of N rectangular permanent magnet (PM) blocks can be used to generate high quality N-pole fields in close proximity to the array axis. In applications featuring small-diameter charged particle beams, N-poles of adequate quality can be realized at relatively low cost using small volumes of PM material. In this paper we report on recent measurements performed on planar PM multipoles, and discuss techniques for improving the field quality of such devices at distances appreciably far away from the axis. Applications to hybrid/PM insertion device designs for linac-driven Free Electron Laser (FEL) operation in the x-ray range are described

  7. Magnetic measurements for RFP experiment on STP-3(M)

    International Nuclear Information System (INIS)

    Nagata, Akiyoshi; Tamaru, Takeshi; Arimoto, Hideki; Yamada, Shuichi; Sato, Koichi.

    1984-03-01

    Magnetic measurements are arranged for RFP experiment on STP-3(M). Magnetic measurements will be applied to investigate the discharge parameters, F(field reversal ratio) - theta(pinch parameter) diagram, the physical mechanism of flux enhancement and the toroidal and poloidal mode numbers due to the MHD instability. Theoretical considerations and instrumental techniques for magnetic measurements are described in detail. (author)

  8. Magnetic memory effects in high temperature superconductors

    International Nuclear Information System (INIS)

    Rockenbauer, A.

    1989-01-01

    Microwave absorption of high temperature oxide superconductors MBa 2 Cu 3 O 7 (M = Y, Er, Dy, Ho, Lu, Tm, Gd) at 77 K have been studied by ESR. In granular samples diamagnetic zero-field resonance and strong ESR baseline hysteresis have been observed: for increasing field sweep - a high, for decreasing one - a low, while in constant field the baseline approaches the middle position with kinetics typical of spin-glasses. The hysteresis amplitude, i.e. the deviation of high and low baselines, possesses maximum at zero field if the sample is cooled down in zero field. In case of field cooling both the diamagnetic resonance and hysteresis maximum are shifted as a function of relative direction of the fields where the samples are cooled and measured, respectively. The shift is caused by the remanent diamagnetism of trapped fluxons. The hysteresis critically depends on the modulation amplitude of magnetic field, and no hysteresis can be observed if the microwave absorption is detected without field modulation. By applying saw-tooth sweep the spin-glass can be driven between two extreme hysteresis states, and the ESR response is rectangular for large saw-tooth amplitude and linear - for small one, while for intermediate amplitudes the recording shows characteristic memory effects. The hysteresis memory is explained in terms of loop distribution of fluxons. In the single crystal the fluxon absorptions are also detected and the separation of fluxon lines can be related to the hysteresis in granular samples. (author)

  9. Design principles for prototype and production magnetic measurements of superconducting magnets

    International Nuclear Information System (INIS)

    Brown, B.C.

    1989-02-01

    The magnetic field strength and shape for SSC superconducting magnets will determine critical properties of the accelerator systems. This paper will enumerate the relations between magnetic field properties and magnet material selection and assembly techniques. Magnitudes of various field errors will be explored along with operating parameters which can affect them. Magnetic field quality requirements will be compared to available measuring techniques and the relation between magnetic field measurements and other quality control efforts will be discussed. This will provide a framework for designing a complete magnet measurement plan for the SSC project. 17 refs., 1 fig., 5 tabs

  10. 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…

  11. Ac magnetic hysteresis loops of Bi-Sr-Ca-Cu-O 110-K-phase superconductors and the effect of microstructural alteration

    International Nuclear Information System (INIS)

    Kumar, N.H.; Bai, V.S.

    1996-01-01

    The field variations of ac M-H loops are recorded at 77 K and 33 Hz using a lock-in flat-band detection method in sintered and press sintered 110-K-phase samples of the Bi-Sr-Ca-Cu-O system. From the slope of the M vs H m curve the flux profiles and the effective relative permeability (μ cer ) of the samples are determined. Using this value of μ cer the intergrain and intragrain contributions to the magnetization are separated out. The intergranular loops of the sintered sample could be simulated very well using Kim close-quote s model, while for the press-sintered sample the exponential model gives a better fit. Our results show that the loop closure exhibited by the intergranular loop can be simulated to the critical state models without subtracting the wing portion in contrast to the Dersch-Blatter approach. The intragranular loops of sintered samples show quite a good fit to the exponential model after introducing the surface barrier modification. The intergranular critical current density (J ci ) and the apparent lower critical field (H c1g ) of the grains are found to be enhanced due to press sintering. The field variations of the various physical quantities obtained from the loops are analyzed to see the effect of microstructural alterations introduced by the press-sintering method. By doing a fast Fourier transform on the M vs t curve the harmonic components are separated out and their variation with the ac field amplitude is studied. copyright 1996 The American Physical Society

  12. Field measurements for low-aperture magnetic elements

    International Nuclear Information System (INIS)

    Mikhajlichenko, A.A.

    1989-01-01

    The method of the field measurements with help of bismuth wire in low aperture magnetic elements is revised. The quadrupole with permanent magnets was tested. It has aperture diameter about 4 mm and length 40 mm. Gradient about 38 kOe/cm was measured. The accuracy of the magnetic axis position definition is better than 1 μm. This method is a good kandidate for linear colider low aperture magnetic elements measurements. 7 refs.; 6 figs

  13. The Kurzweil integral and hysteresis

    International Nuclear Information System (INIS)

    Krejci, P

    2006-01-01

    A hysteresis operator, called the play, with variable (possibly degenerate) characteristics, is considered in the space of right-continuous regulated functions. The Lipschitz continuity of the input-output mapping is proved by means of a new technique based on the Kurzweil integral

  14. 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.

  15. Influence of martensitic transformation on the magnetic transition in Ni-Mn-Ga

    Energy Technology Data Exchange (ETDEWEB)

    Kokorin, V.V. [Institute of Magnetism of NASU and MESU, Vernadsky blvd., 03680 Kyiv (Ukraine); Konoplyuk, S.M., E-mail: ksm@imag.kiev.ua [Institute of Magnetism of NASU and MESU, Vernadsky blvd., 03680 Kyiv (Ukraine); Dalinger, A.; Maier, H.J. [Institut für Werkstoffkunde (Materials Science), Leibnitz Universität Hannover, An der Universität 2, D-30823 Garbsen (Germany)

    2017-06-15

    Highlights: • The magnetic transition with temperature hysteresis occurs in Ni{sub 51.9}Mn{sub 27}Ga{sub 211}. • Its second-order character is confirmed by magnetic measurements. • The reason for this phenomenon lies in temperature dependence of lattice constant. - Abstract: The magnetic transition with a temperature hysteresis of about 7 K was observed in the martensitic phase of Ni{sub 51.9}Mn{sub 27}Ga{sub 211}. The measurements of AC magnetic susceptibility in constant magnetic fields up to 570 kA/m have proved its magnetic origin. The transport and caloric measurements were used to gain better understanding of the nature of this phenomenon. The variation of the martensite lattice parameters with temperature is suggested to account for the hysteresis of the magnetic transition.

  16. 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.

  17. Magnetism and the interior of the moon. [measured at Apollo landing sites

    Science.gov (United States)

    Dyal, P.; Parkin, C. W.; Daily, W. D.

    1974-01-01

    During the time period 1961-1972 eleven magnetometers were sent to the moon. The results of lunar magnetometer data analysis are reviewed, with emphasis on the lunar interior. Magnetic fields have been measured on the lunar surface at the Apollo 12, 14, 15, and 16 landing sites. The remanent field values at these sites are given. Satellite and surface measurements show strong evidence that the lunar crust is magnetized over much of the lunar globe. The origin of the lunar remanent field is not yet satisfactorily understood; several source models are presented. Simultaneous data from the Apollo 12 lunar surface magnetometer and the Explorer 35 Ames magnetometer are used to construct a wholemoon hysteresis curve, from which the global lunar permeability is determined. Total iron abundance is calculated for two assumed compositional models of the lunar interior. Other lunar models with a small iron core and with a shallow iron-rich layer are also discussed in light of the measured global permeability.

  18. Specific absorption rate determination of magnetic nanoparticles through hyperthermia measurements in non-adiabatic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Coïsson, M. [INRIM, strada delle Cacce 91, 10135 Torino (Italy); Barrera, G. [INRIM, strada delle Cacce 91, 10135 Torino (Italy); University of Torino, Chemistry Department, via P. Giuria 7, 10125 Torino (Italy); Celegato, F.; Martino, L.; Vinai, F. [INRIM, strada delle Cacce 91, 10135 Torino (Italy); Martino, P. [Politronica srl, via Livorno 60, 10144 Torino (Italy); Ferraro, G. [Center for Space Human Robotics, Istituto Italiano di Tecnologia - IIT, corso Trento 21, 10129 Torino (Italy); Tiberto, P. [INRIM, strada delle Cacce 91, 10135 Torino (Italy)

    2016-10-01

    An experimental setup for magnetic hyperthermia operating in non-adiabatic conditions is described. A thermodynamic model that takes into account the heat exchanged by the sample with the surrounding environment is developed. A suitable calibration procedure is proposed that allows the experimental validation of the model. Specific absorption rate can then be accurately determined just from the measurement of the sample temperature at the equilibrium steady state. The setup and the measurement procedure represent a simplification with respect to other systems requiring calorimeters or crucial corrections for heat flow. Two families of magnetic nanoparticles, one superparamagnetic and one characterised by larger sizes and static hysteresis, have been characterised as a function of field intensity, and specific absorption rate and intrinsic loss power have been obtained. - Highlights: • Development and thermodynamic modelling of a hyperthermia setup operating in non-adiabatic conditions. • Calibration of the experimental setup and validation of the model. • Accurate measurement of specific absorption rate and intrinsic loss power in non-adiabatic conditions.

  19. 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

  20. Measuring magnetic field vector by stimulated Raman transitions

    International Nuclear Information System (INIS)

    Wang, Wenli; Wei, Rong; Lin, Jinda; Wang, Yuzhu; Dong, Richang; Zou, Fan; Chen, Tingting

    2016-01-01

    We present a method for measuring the magnetic field vector in an atomic fountain by probing the line strength of stimulated Raman transitions. The relative line strength for a Λ-type level system with an existing magnetic field is theoretically analyzed. The magnetic field vector measured by our proposed method is consistent well with that by the traditional bias magnetic field method with an axial resolution of 6.1 mrad and a radial resolution of 0.16 rad. Dependences of the Raman transitions on laser polarization schemes are also analyzed. Our method offers the potential advantages for magnetic field measurement without requiring additional bias fields, beyond the limitation of magnetic field intensity, and extending the spatial measurement range. The proposed method can be widely used for measuring magnetic field vector in other precision measurement fields.

  1. Geochemical Controls on Nuclear Magnetic Resonance Measurements

    International Nuclear Information System (INIS)

    Knight, Rosemary; Prasad, Manika; Keating, Kristina

    2003-01-01

    OAK-B135 Our research objectives are to determine, through an extensive set of laboratory experiments, the effect of the specific mineralogic form of iron and the effect of the distribution of iron on proton nuclear magnetic resonance (NMR) relaxation mechanisms. In the first nine months of this project, we have refined the experimental procedures to be used in the acquisition of the laboratory NMR data; have ordered, and conducted preliminary measurements on, the sand samples to be used in the experimental work; and have revised and completed the theoretical model to use in this project. Over the next year, our focus will be on completing the first phase of the experimental work where the form and distribution of the iron in the sands in varied

  2. Magnetic Particle inspection by DC and AC magnetization current

    International Nuclear Information System (INIS)

    Lim, Zhong Soo; Kim, Goo Hwa

    1996-01-01

    Dry magnetic particle inspection was performed to detect the surface defects of the steel billets. The detectability was evaluated according to magnetizing current, temperature, and amount of the magnetic particles on material. We selected a certain set of steel compositions for target materials. Their magnetic properties are measured with B-H hysteresis graph. Results of the magnetic particle inspection(MPI) by direct magnetizing current was compared with results of the finite element method calculations, which were verified by measurement of the magnetic leakage flux above the surface of material. For square rod materials, the magnetic flux density at the corner was about 30% of that at the face center with sufficiently large direct magnetizing current, while it is about 70% with alternating magnetizing current. Alternating magnetizing current generates rather uniform magnetic flux density running from the center to the corner except for the region of about 10 mm extending from the corner.

  3. Magnetic susceptibility measurement using 2D magnetic resonance imaging

    Czech Academy of Sciences Publication Activity Database

    Marcon, P.; Bartušek, Karel; Burdkova, M.; Dokoupil, Zdeněk

    2011-01-01

    Roč. 22, č. 10 (2011), 105702:1-8 ISSN 0957-0233 R&D Projects: GA ČR GAP102/11/0318; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : magnetic flux density * magnetic susceptibility * MRI * MR signal * reaction field Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.494, year: 2011

  4. Magnetic measurements of the steel septum magnet used for extraction: MSDC01

    CERN Document Server

    Cornuet, D; Leclère, P

    2002-01-01

    The proton beams extracted from the LHC are dumped on external absorbers by horizontally deflecting kicker magnets and vertically deflecting steel septum magnets. For this system there are three variants of steel septum magnets MSD A, MSD B and MSD C, which will be produced by the Institute of High Energy Physics (IHEP, Protvino/Russia). This document gives the results of the magnetic measurements at CERN on the first magnet of the series: MSDC01.

  5. 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...

  6. AC magnetic measurements of the ALS Booster Synchrotron Dipole Magnet engineering model

    International Nuclear Information System (INIS)

    Green, M.I.; Hoyer, E.; Keller, R.; Nelson, D.H.

    1988-09-01

    We made a minimal set of AC magnetic measurements of the engineering model of the ALS Booster Dipole Magnet as part of the process of qualifying its design for production. Magnetic induction integrals over paths approximating electron-beam trajectories were measured with long curved coils connected to an electronic integrator. Magnetic induction was measured with point coils and an integrator and independently with a Hall-effect Gaussmeter. These quantities, and magnet current, were displayed on a commercial digital storage oscilloscope as parametric functions of time. The displayed waveforms were stored, processed and redisplayed as representations of selected magnet parameters. A waveform representing the magnet's effective-length was created by dividing the integral waveform by the magnetic induction waveform. Waveforms of the transfer functions were produced by dividing both the integral waveform and the magnetic induction waveform by the current waveform. Pairs of matched coils, connected in series opposition, provided differential measurements of field uniformity. Quadrupole and sextupole coefficients were derived from the uniformity data. These magnet parameters were measured at 2 and 10 Hz frequencies. Together with measurements of the magnetic field at selected dc levels, the ac measurements demonstrated that the magnet design met specifications and qualified it for production. 7 refs., 7 figs., 3 tabs

  7. The Kurzweil integral and hysteresis

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Pavel

    2006-01-01

    Roč. 55, - (2006), s. 144-154 ISSN 1742-6588. [International Workshop on Multi-Rate Processes and Hysteresis. Cork , 03.04.2006-08.04.2006] Institutional research plan: CEZ:AV0Z10190503 Keywords : regulated functions * space Subject RIV: BA - General Mathematics http://iopscience.iop.org/1742-6596/55/1/014/pdf/1742-6596_55_1_014.pdf

  8. Hysteresis in audiovisual synchrony perception.

    Directory of Open Access Journals (Sweden)

    Jean-Rémy Martin

    Full Text Available The effect of stimulation history on the perception of a current event can yield two opposite effects, namely: adaptation or hysteresis. The perception of the current event thus goes in the opposite or in the same direction as prior stimulation, respectively. In audiovisual (AV synchrony perception, adaptation effects have primarily been reported. Here, we tested if perceptual hysteresis could also be observed over adaptation in AV timing perception by varying different experimental conditions. Participants were asked to judge the synchrony of the last (test stimulus of an AV sequence with either constant or gradually changing AV intervals (constant and dynamic condition, respectively. The onset timing of the test stimulus could be cued or not (prospective vs. retrospective condition, respectively. We observed hysteretic effects for AV synchrony judgments in the retrospective condition that were independent of the constant or dynamic nature of the adapted stimuli; these effects disappeared in the prospective condition. The present findings suggest that knowing when to estimate a stimulus property has a crucial impact on perceptual simultaneity judgments. Our results extend beyond AV timing perception, and have strong implications regarding the comparative study of hysteresis and adaptation phenomena.

  9. 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...

  10. 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...

  11. Analysis of magnetic field measurement results for the AGS Booster magnets

    International Nuclear Information System (INIS)

    Bleser, E.; Thern, R.

    1991-01-01

    Magnetic field measurements have been made on nearly 200 conventional magnets that have been installed in the AGS Booster and its associated transfer lines. The measurements were intended to monitor the quality of the magnets being produced and to check the performance of each magnet before installation. The magnetic measurements effort led to certain improvements in the manufacturing process, which ten subsequently produced very good, very uniform magnets. The integrated dipole fields of the 36 booster dipoles are uniform to 1.5 parts in ten thousand. The magnetic measurements indicate that the quadrupoles were manufactured to an accuracy of 3 ten thousandths of an inch, which is better than we can physically measure. 3 refs., 2 figs., 4 tabs

  12. Impact of back-gate bias on the hysteresis effect in partially depleted SOI MOSFETs

    International Nuclear Information System (INIS)

    Luo Jie-Xin; Chen Jing; Zhou Jian-Hua; Wu Qing-Qing; Chai Zhan; Yu Tao; Wang Xi

    2012-01-01

    The hysteresis effect in the output characteristics, originating from the floating body effect, has been measured in partially depleted (PD) silicon-on-insulator (SOI) MOSFETs at different back-gate biases. I D hysteresis has been developed to clarify the hysteresis characteristics. The fabricated devices show the positive and negative peaks in the I D hysteresis. The experimental results show that the I D hysteresis is sensitive to the back gate bias in 0.13-μm PD SOI MOSFETs and does not vary monotonously with the back-gate bias. Based on the steady-state Shockley-Read-Hall (SRH) recombination theory, we have successfully interpreted the impact of the back-gate bias on the hysteresis effect in PD SOI MOSFETs. (condensed matter: structural, mechanical, and thermal properties)

  13. Effect of hydraulic hysteresis on the stability of infinite slopes under steady infiltration

    Science.gov (United States)

    Chen, Pan; Mirus, Benjamin B.; Lu, Ning; Godt, Jonathan W.

    2017-01-01

    Hydraulic hysteresis, including capillary soil water retention (SWR), air entrapment SWR, and hydraulic conductivity, is a common phenomenon in unsaturated soils. However, the influence of hydraulic hysteresis on suction stress, and subsequently slope stability, is generally ignored. This paper examines the influence of each of these three types of hysteresis on slope stability using an infinite slope stability analysis under steady infiltration conditions. First, hypothetical slopes for representative silty and sandy soils are examined. Then a monitored hillslope in the San Francisco Bay Area, California is assessed, using observed rainfall conditions and measured hydraulic and geotechnical properties of the colluvial soil. Results show that profiles of suction stress and the corresponding factor of safety are generally strongly affected by hydraulic hysteresis. Results suggest that each of the three types of hydraulic hysteresis may play a major role in the occurrence of slope failure, indicating that ignoring hydraulic hysteresis will likely lead to underestimates of failure potential and hence to inaccurate slope stability analysis.

  14. Improving sensitivity to magnetic fields and electric dipole moments by using measurements of individual magnetic sublevels

    Science.gov (United States)

    Tang, Cheng; Zhang, Teng; Weiss, David S.

    2018-03-01

    We explore ways to use the ability to measure the populations of individual magnetic sublevels to improve the sensitivity of magnetic field measurements and measurements of atomic electric dipole moments (EDMs). When atoms are initialized in the m =0 magnetic sublevel, the shot-noise-limited uncertainty of these measurements is 1 /√{2 F (F +1 ) } smaller than that of a Larmor precession measurement. When the populations in the even (or odd) magnetic sublevels are combined, we show that these measurements are independent of the tensor Stark shift and the second order Zeeman shift. We discuss the complicating effect of a transverse magnetic field and show that when the ratio of the tensor Stark shift to the transverse magnetic field is sufficiently large, an EDM measurement with atoms initialized in the superposition of the stretched states can reach the optimal sensitivity.

  15. Measurement procedure for CBETA Halbach Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, S. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2017-11-08

    The CBETA magnets will be marked by the manufacturer with two sides called “A” and “B”, as well as which part of the magnet is the “top” vertically. The significances of these sides are given in the table below.

  16. Nanosecond-resolved temperature measurements using magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wenbiao; Zhang, Pu [School of Automation, Huazhong University of Science and Technology, Wuhan 430074 (China); Liu, Wenzhong, E-mail: lwz7410@hust.edu.cn [School of Automation, Huazhong University of Science and Technology, Wuhan 430074 (China); Key Laboratory of Image Processing and Intelligent Control, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2016-05-15

    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.

  17. Magnetic susceptibility measurements on Bi - Sn alloys

    International Nuclear Information System (INIS)

    Mustaffa bin Haji Abdullah

    1985-01-01

    Magnetic susceptibility measurements on eight samples of tin-rich and three samples of bismuth-rich Bi-Sn alloys were made from 85K to 300K by Faraday's method. The susceptibilities of the eight tin-rich samples are positive and greater than the susceptibility of pure tin. The values are approximately constant at low temperatures but decreasing a little bit with increasing temperature. This result is interpreted as due to the predominant contribution of the Pauli spin paramagnetic susceptibility. A small decrease in susceptibility with temperature is interpreted as due to the effect of the second order term in the expression for spin paramagnetic susceptibility. The fluctuation of the susceptibility for alloys of different composition is interpreted as due to the effect of the density of states at the Fermi levels. The three samples of bismuth-rich alloys show a transition to diamagnetic property, where the diamagnetism is increased with temperature. This result is predominant and due to the diamagnetic contribution from the ions. The increase in susceptibility with temperature is interpreted as due to an increase in the effective radii of the ions due to thermal expansion. (author)

  18. Transient finite element magnetic field calculation method in the anisotropic magnetic material based on the measured magnetization curves

    International Nuclear Information System (INIS)

    Jesenik, M.; Gorican, V.; Trlep, M.; Hamler, A.; Stumberger, B.

    2006-01-01

    A lot of magnetic materials are anisotropic. In the 3D finite element method calculation, anisotropy of the material is taken into account. Anisotropic magnetic material is described with magnetization curves for different magnetization directions. The 3D transient calculation of the rotational magnetic field in the sample of the round rotational single sheet tester with circular sample considering eddy currents is made and compared with the measurement to verify the correctness of the method and to analyze the magnetic field in the sample

  19. Measurement of the D0 WAMUS magnet inductance

    International Nuclear Information System (INIS)

    Kristalinski, A.; Hance, R.; Jaskierny, W.

    1994-12-01

    Historically, the term inductance, as it relates to magnets, has been relatively obscure at Fermilab. Confusion resulted from the typical engineering approach to the matter, whereby distinction may not have been made between analytical and beam line magnets; and distribution transformers. The latter always have a laminated core to reduce eddy currents which makes their inductance in a transitional state very close to that in a steady state. This is true only if the core material is not in saturation, which is once again the case for transformers; but not for magnets, especially the analytical ones. Based on the traditional ''transformer'' thinking, an incorrect method to measure magnet inductance was initially employed. The characteristics of a tank circuit including the magnet under test were observed. Then based on the resonant frequency and quality factor, the inductance was calculated. This method represents a very valuable tool for magnet testing where you can compare newly built magnets to a reference magnet and see if there is any difference. Although electrically correct, this method unfortunately does not reveal any valuable information which could be used to anticipate the magnet behavior under the normal working conditions. Another method of measuring inductance, based on a freewheeling discharge of the magnet, is also widely used in the Lab. To measure the inductance, a magnet is powered from a small power supply for up to 100 A to 200 A, then the power is turned off and the current decay in the magnet is recorded. Based on the dc resistance measurements and the magnet current decay data, one can determine the magnet inductance. In order to do so, the inductance is assumed to be constant and current decay is assumed to be exponential. To find out how well the effective inductance represents the real process taking place in the magnet was one of the purposes of the experiment

  20. Electrical measurement, signal processing, and displays

    CERN Document Server

    Webster, John G

    2003-01-01

    ELECTROMAGNETIC VARIABLES MEASUREMENTVoltage MeasurementCurrent Measurement Power Measurement Power Factor Measurement Phase Measurement Energy Measurement Electrical Conductivity and Resistivity Charge Measurement Capacitance and Capacitance Measurements Permittivity Measurement Electric Field Strength Magnetic Field Measurement Permeability and Hysteresis MeasurementInductance Measurement Immittance MeasurementQ Factor Measurement Distortion Measurement Noise Measurement.Microwave Measurement SIGNAL PROCESSINGAmplifiers and Signal ConditionersModulation Filters Spectrum Analysis and Correlat

  1. Magnetic Ghosts: Mineral Magnetic Measurements On Roman and Anglo-saxon Graves

    Science.gov (United States)

    Linford, N.

    The location of inhumations, in the absence of ferrous grave goods, often presents a considerable challenge to archaeological geophysics given the small physical size of the features and the slight contrast between the fill of the grave and the surround- ing subsoil. Even during excavation, the identification of graves may be complicated where site conditions do not favour the preservation of human skeletal remains and often only a subtle soil stain is likely to survive. A recent initiative in the United King- dom has seen the formation of the Buried Organic Matter Decomposition Integrated with Elemental Status (BODIES) research group, to examine the decomposition of organic artefacts in ancient graves with respect to localised changes in pH, redox po- tential and nutrient status. This paper presents initial results from a limited mineral magnetic study of two grave sites in an attempt to ascertain whether the decomposi- tion of organic remains may lead to a detectable magnetic signature within the soil. Results from a series of isothermal, hysteresis and magneto-thermal experiments will be presented together with surface magnetometer and topsoil susceptibility surveys.

  2. Cryogenic system for the HERA magnet measurement facility

    International Nuclear Information System (INIS)

    Barton, H.R. Jr.; Clausen, M.; Kebler, G.

    1986-01-01

    This paper describes the design for a helium, cryogenic distribution system that allows independent operation and testing of superconducting magnets of the HERA project before they are installed in the 6-km ring tunnel. The 820-GeV proton storage ring of HERA will contain approximately 650 magnets having superconducting coils which are clamped by aluminum/stainless-steel collars and surrounded by a yoke of magnetic iron at liquid helium temperature. When the magnets arive at DESY from the manufacture, each magnet will be individually tested at helium operating conditions in the magnet measurement facility to insure the quality of the magnetic characteristics and the cryogenic performance. The capabilities of the cryogenic system and the schedule for magnet testing are discussed

  3. Magnetic field measurements of 1.5 meter model SSC collider dipole magnets at Fermilab

    International Nuclear Information System (INIS)

    Lamm, M.J.; Bleadon, M.; Coulter, K.J.; Delchamps, S.; Hanft, R.; Jaffery, T.S.; Kinney, W.; Koska, W.; Ozelis, J.P.; Strait, J.; Wake, M.; DiMarco, J.

    1991-09-01

    Magnetic field measurements have been performed at Fermilab on 1.5 m magnetic length model dipoles for the Superconducting Supercollider. Harmonic measurements are recorded at room temperature before and after the collared coil is assembled into the yoke and at liquid helium temperature. Measurements are made as a function of longitudinal position and excitation current. High field data are compared with room temperature measurements of both the collared coil and the completed yoked magnet and with the predicted fields for both the body of the magnet and the coil ends

  4. SLC Arc transport system: AG-magnet measurement and performance

    International Nuclear Information System (INIS)

    Weng, W.T.; Anderson, M.; Byers, R.; Cobb, J.; Fischer, G.; Hamilton, V.

    1985-03-01

    This paper describes the design, construction, and operation of devices used to rapidly measure the mechanical and magnetic properties of some 950 Alternate gradient magnets used in the arc system of the Stanford Linear Collider. The problems of dealing with the measurement of the transverse dimensions to within minute (0.0001 in.) resolution of objects that are 8 ft long are discussed. Early results from the production runs of these magnets are presented. 7 refs., 6 figs

  5. Measurement of magnetic properties of confined compact toroid plasma (spheromak)

    International Nuclear Information System (INIS)

    Hwang, Fu-Kwun.

    1991-01-01

    The theoretical aspect of the spheromak is described in this paper. The MS machine hardware will be explored along with the formation scheme and diagnostic systems. The magnetic pickup probes, their calibration procedures and the data analysis methods will be discussed. Observations from the probe measurements and magnetic properties of the MS spheromak are considered. The axisymmetric Grad-Shafranov equilibrium code calculations are presented and compared with the measurements. Magnetic helicity and its correlation with the experimental observations is described

  6. Advanced Sensors for Airborne Magnetic Measurements

    National Research Council Canada - National Science Library

    Bobb, L

    2001-01-01

    Numerous ground tests and platform tests were conducted to evaluate platform integration issues and the performance of the POLATOMIC 2000 magnetometer, a laser-pumped helium-4 total magnetic field sensor...

  7. Ferro electricity from magnetic order by neutron measurement

    International Nuclear Information System (INIS)

    Kenzelmann, M.

    2009-01-01

    Magnetic insulators with competing exchange interactions can give rise to strong fluctuations and qualitatively new ground states. The proximity of such systems to quantum critical points can lead to strong cross-coupling between magnetic long-range order and the nuclear lattice. Case in point is a new class of multiferroic materials in which the magnetic and ferroelectric order parameters are directly coupled, and a magnetic field can suppress or switch the electric polarization [1]. Our neutron measurements reveal that ferro electricity is induced by magnetic order and emerges only if the magnetic structure creates a polar axis [2-5]. Our measurements provide evidence that commensurate magnetic order can produce ferro electricity with large electric polarization [6]. The spin dynamics and the field-temperature phase diagram of the ordered phases provide evidence that competing ground states are essential for ferro electricity. (author)

  8. Effects of hysteresis and Brayton cycle constraints on magnetocaloric refrigerant performance

    Science.gov (United States)

    Brown, T. D.; Buffington, T.; Shamberger, P. J.

    2018-05-01

    Despite promising proofs of concept, system-level implementation of magnetic refrigeration has been critically limited by history-dependent refrigerant losses that interact with governing thermodynamic cycles to adversely impact refrigeration performance. Future development demands a more detailed understanding of how hysteresis limits performance, and of how different types of cycles can mitigate these limitations, but without the extreme cost of experimental realization. Here, the utility of Brayton cycles for magnetic refrigeration is investigated via direct simulation, using a combined thermodynamic-hysteresis modeling framework to compute the path-dependent magnetization and entropy of a model alloy for a variety of feasible Brayton cycles between 0-1.5 T and 0-5 T. By simultaneously varying the model alloy's hysteresis properties and applying extensions of the thermodynamic laws to non-equilibrium systems, heat transfers and efficiencies are quantified throughout the space of hystereses and Brayton cycles and then compared with a previous investigation using Ericsson cycles. It is found that (1) hysteresis losses remain a critical obstacle to magnetic refrigeration implementation, with efficiencies >80% in the model system requiring hysteresis refrigerant transformation temperatures at the relevant fields; (3) for a given hysteresis and field constraint, Brayton and Ericsson-type cycles generate similar efficiencies; for a given temperature span, Ericsson cycles lift more heat per cycle, with the difference decreasing with the refrigerant heat capacity outside the phase transformation region.

  9. GEOCHEMICAL CONTROLS ON NUCLEAR MAGNETIC RESONANCE MEASUREMENTS

    International Nuclear Information System (INIS)

    Knight, Rosemary

    2008-01-01

    Proton nuclear magnetic resonance (NMR) is used in the Earth Sciences as a means of obtaining information about the molecular-scale environment of fluids in porous geological materials. Laboratory experiments were conducted to advance our fundamental understanding of the link between the NMR response and the geochemical properties of geological materials. In the first part of this research project, we studied the impact of both the surface-area-to-volume ratio (S/V) of the pore space and the surface relaxivity on the NMR response of fluids in sand-clay mixtures. This study highlighted the way in which these two parameters control our ability to use NMR measurements to detect and quantify fluid saturation in multiphase saturated systems. The second part of the project was designed to explore the way in which the mineralogic form of iron, as opposed to simply the concentration of iron, affects the surface relaxation rate and, more generally, the NMR response of porous materials. We found that the magnitude of the surface relaxation rate was different for the various iron-oxide minerals because of changes in both the surface-area-to-volume ratio of the pore space, and the surface relaxivity. Of particular significance from this study was the finding of an anomalously large surface relaxivity of magnetite compared to that of the other iron minerals. Differences in the NMR response of iron minerals were seen in column experiments during the reaction of ferrihydrite-coated quartz sand with aqueous Fe(II) solutions to form goethite, lepidocrocite and magnetite; indicating the potential use of NMR as a means of monitoring geochemical reactions. The final part of the research project investigated the impact of heterogeneity, at the pore-scale, on the NMR response. This work highlighted the way in which the geochemistry, by controlling the surface relaxivity, has a significant impact on the link between NMR data and the microgeometry of the pore space.

  10. An efficient hysteresis modeling methodology and its implementation in field computation applications

    Energy Technology Data Exchange (ETDEWEB)

    Adly, A.A., E-mail: adlyamr@gmail.com [Electrical Power and Machines Dept., Faculty of Engineering, Cairo University, Giza 12613 (Egypt); Abd-El-Hafiz, S.K. [Engineering Mathematics Department, Faculty of Engineering, Cairo University, Giza 12613 (Egypt)

    2017-07-15

    Highlights: • An approach to simulate hysteresis while taking shape anisotropy into consideration. • Utilizing the ensemble of triangular sub-regions hysteresis models in field computation. • A novel tool capable of carrying out field computation while keeping track of hysteresis losses. • The approach may be extended for 3D tetra-hedra sub-volumes. - Abstract: Field computation in media exhibiting hysteresis is crucial to a variety of applications such as magnetic recording processes and accurate determination of core losses in power devices. Recently, Hopfield neural networks (HNN) have been successfully configured to construct scalar and vector hysteresis models. This paper presents an efficient hysteresis modeling methodology and its implementation in field computation applications. The methodology is based on the application of the integral equation approach on discretized triangular magnetic sub-regions. Within every triangular sub-region, hysteresis properties are realized using a 3-node HNN. Details of the approach and sample computation results are given in the paper.

  11. On the problem of contextuality in macroscopic magnetization measurements

    International Nuclear Information System (INIS)

    Soeda, Akihito; Kurzyński, Paweł; Ramanathan, Ravishankar; Grudka, Andrzej; Thompson, Jayne; Kaszlikowski, Dagomir

    2013-01-01

    We show that sharp measurements of total magnetization cannot be used to reveal contextuality in macroscopic many-body systems of spins of arbitrary dimension. We decompose each such measurement into set of projectors corresponding to well-defined value of total magnetization. We then show that such sets of projectors are too restricted to construct Kochen–Specker sets.

  12. 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...

  13. Measurement of AC electrical characteristics of SSC superconducting dipole magnets

    International Nuclear Information System (INIS)

    Smedley, K.M.; Shafer, R.E.

    1992-01-01

    Experiments were conducted to measure the AC electrical characteristics of SSC superconducting dipole magnets over the frequency range of 0.1 Hz to 10 kHz. A magnet equivalent circuit representing the magnet DC inductance, eddy current losses, coil-to-ground and turn-to-turn capacitance, was synthesized from the experimental data. This magnet equivalent circuit can be used to predict the current ripple distribution along the superconducting magnet string and can provide dynamic information for the design of the collider current regulation loop

  14. Hysteresis of boiling for different tunnel-pore surfaces

    Directory of Open Access Journals (Sweden)

    Pastuszko Robert

    2015-01-01

    Full Text Available Analysis of boiling hysteresis on structured surfaces covered with perforated foil is proposed. Hysteresis is an adverse phenomenon, preventing high heat flux systems from thermal stabilization, characterized by a boiling curve variation at an increase and decrease of heat flux density. Experimental data were discussed for three kinds of enhanced surfaces: tunnel structures (TS, narrow tunnel structures (NTS and mini-fins covered with the copper wire net (NTS-L. The experiments were carried out with water, R-123 and FC-72 at atmospheric pressure. A detailed analysis of the measurement results identified several cases of type I, II and III for TS, NTS and NTS-L surfaces.

  15. Hysteresis Phenomena in Sulfur Dioxide Oxidation over Supported Vanadium Catalysts

    DEFF Research Database (Denmark)

    Masters, Stephen G.; Eriksen, Kim Michael; Fehrmann, Rasmus

    1997-01-01

    Catalyst deactivation and hysteresis behavior in industrial SO2-oxidation catalysts have been studied in the temperature region 350-480 C by combined in situ EPR spectroscopy and catalytic activity measurements. The feed gas composition simulated sulfuric acid synthesis gas and wet/dry de......NOx'ed flue gas. The vanadium (IV) compound K4(VO)3(SO4)5 precipitated during all the investigated conditions hence causing catalyst deactivation. Hysteresis behavior of both the catalytic activity and the V(IV) content was observed during reheating....

  16. Hysteresis and compensation behaviors of spin-3/2 cylindrical Ising nanotube system

    International Nuclear Information System (INIS)

    Kocakaplan, Yusuf; Keskin, Mustafa

    2014-01-01

    The hysteresis and compensation behaviors of the spin-3/2 cylindrical Ising nanotube system are studied within the framework of the effective-field theory with correlations. The effects of the Hamiltonian parameters are investigated on the magnetic and thermodynamic quantities, such as the total magnetization, hysteresis curves, and compensation behaviors of the system. Depending on the Hamiltonian parameters, some characteristic hysteresis behaviors are found, such as the existence of double and triple hysteresis loops. According to Néel classification nomenclature, the system displays Q-, R-, P-, N-, M-, and S- types of compensation behaviors for the appropriate values of the system parameters. We also compare our results with some recently published theoretical and experimental works and find a qualitatively good agreement

  17. Hysteresis and compensation behaviors of spin-3/2 cylindrical Ising nanotube system

    Energy Technology Data Exchange (ETDEWEB)

    Kocakaplan, Yusuf [Graduate School of Natural and Applied Sciences, Erciyes University, 38039 Kayseri (Turkey); Keskin, Mustafa, E-mail: keskin@erciyes.edu.tr [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

    2014-09-07

    The hysteresis and compensation behaviors of the spin-3/2 cylindrical Ising nanotube system are studied within the framework of the effective-field theory with correlations. The effects of the Hamiltonian parameters are investigated on the magnetic and thermodynamic quantities, such as the total magnetization, hysteresis curves, and compensation behaviors of the system. Depending on the Hamiltonian parameters, some characteristic hysteresis behaviors are found, such as the existence of double and triple hysteresis loops. According to Néel classification nomenclature, the system displays Q-, R-, P-, N-, M-, and S- types of compensation behaviors for the appropriate values of the system parameters. We also compare our results with some recently published theoretical and experimental works and find a qualitatively good agreement.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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

  19. Hysteresis development in superconducting Josephson junctions

    International Nuclear Information System (INIS)

    Refai, T.F.; Shehata, L.N.

    1988-09-01

    The resistively and capacitive shunted junction model is used to investigate hysteresis development in superconducting Josephson junctions. Two empirical formulas that relate the hysteresis width and the quasi-particle diffusion length in terms of the junctions electrical parameters, temperature and frequency are obtained. The obtained formulas provide a simple tool to investigate the full potentials of the hysteresis phenomena. (author). 9 refs, 3 figs

  20. Mapping system, magnetic measurement and shimming in CRM cyclotron

    International Nuclear Information System (INIS)

    Zhong Junqing; Lv Yinlong; Yin Zhiguo

    2008-01-01

    The Central Region Model (CRM) is a compact H - cyclotron. Because of the intrinsic asymmetry of the magnet, its machining and assembly are very complicated. To guarantee the magnet field distribution, it is necessary to measure and shim the magnetic field. This paper presents a study on the design and use of the mapping system based on the Hall Effect and the re-machining of shimming bars after analyzing the magnetic field measurement data to achieve the isochronous field and good vertical focusing frequency. The method to effectively reduce the amplitude of the 1st harmonic by shimming bars 1s also introduced. (authors)

  1. SUPERCONDUCTING HELICAL SNAKE MAGNETS: CONSTRUCTION AND MEASUREMENTS

    International Nuclear Information System (INIS)

    Mackay, W.W.; Anerella, M.; Courant, E.

    1999-01-01

    In order to collide polarized protons, the RHIC project will have two snakes in each ring and four rotators around each of two interaction regions. Two snakes on opposite sides of each ring can minimize depolarization during acceleration by keeping the spin tune at a half. Since the spin direction is normally along the vertical direction in a flat ring, spin rotators must be used around an interaction point to have longitudinal polarization in a collider experiment. Each snake or rotator will be composed of four helical dipoles to provide the required rotation of spin with minimal transverse orbit excursions in a compact length of 10m. The basic helical dipole is a superconducting magnet producing a transverse dipole field which is twisted about the magnet axis through 360 o in a length of 2.4 m. The design and construction of the magnets is described in this paper

  2. Magnetic measurements of the correction and adjustment magnets of the main ring

    International Nuclear Information System (INIS)

    Trbojevic, D.

    1986-07-01

    Correction magnets correct the field imperfections and alignment errors of the main quadrupole and bend magnets. For reducing and controlling chromaticity there are 186 sextupoles and 78 octupoles, while for suppressing various resonances there are 12 normal and 18 skew sextupoles and 24 normal and 19 skew quadrupoles. Beam positions are individually controlled by 108 horizontal and 108 skew dipoles. This report includes results of the all Main Ring correction and adjustment magnet harmonic measurements. The measurement principle and basic equations are described

  3. A Stable Pentagonal Bipyramidal Dy(III) Single-Ion Magnet with a Record Magnetization Reversal Barrier over 1000 K.

    Science.gov (United States)

    Liu, Jiang; Chen, Yan-Cong; Liu, Jun-Liang; Vieru, Veacheslav; Ungur, Liviu; Jia, Jian-Hua; Chibotaru, Liviu F; Lan, Yanhua; Wernsdorfer, Wolfgang; Gao, Song; Chen, Xiao-Ming; Tong, Ming-Liang

    2016-04-27

    Single-molecule magnets (SMMs) with a large spin reversal barrier have been recognized to exhibit slow magnetic relaxation that can lead to a magnetic hysteresis loop. Synthesis of highly stable SMMs with both large energy barriers and significantly slow relaxation times is challenging. Here, we report two highly stable and neutral Dy(III) classical coordination compounds with pentagonal bipyramidal local geometry that exhibit SMM behavior. Weak intermolecular interactions in the undiluted single crystals are first observed for mononuclear lanthanide SMMs by micro-SQUID measurements. The investigation of magnetic relaxation reveals the thermally activated quantum tunneling of magnetization through the third excited Kramers doublet, owing to the increased axial magnetic anisotropy and weaker transverse magnetic anisotropy. As a result, pronounced magnetic hysteresis loops up to 14 K are observed, and the effective energy barrier (Ueff = 1025 K) for relaxation of magnetization reached a breakthrough among the SMMs.

  4. Effect of the Hamiltonian parameters on the hysteresis properties of the kinetic mixed spin (1/2, 1) Ising ferrimagnetic model on a hexagonal lattice

    Energy Technology Data Exchange (ETDEWEB)

    Batı, Mehmet, E-mail: mehmet.bati@erdogan.edu.tr [Department of Physics, Recep Tayyip Erdoğan University, 53100 Rize (Turkey); Ertaş, Mehmet [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

    2017-05-15

    The hysteresis properties of a kinetic mixed spin (1/2, 1) Ising ferrimagnetic system on a hexagonal lattice are studied by means of the dynamic mean field theory. In the present study, the effects of the nearest-neighbor interaction, temperature, frequency of oscillating magnetic field and the exchange anisotropy on the hysteresis properties of the kinetic system are discussed in detail. A number of interesting phenomena such as the shape of hysteresis loops with one, two, three and inverted-hysteresis/proteresis (butterfly shape hysteresis) have been obtained. Finally, the obtained results are compared with some experimental and theoretical results and a qualitatively good agreement is found.

  5. Electrical conductivity and magnetic permeability measurement of case hardened steels

    Science.gov (United States)

    Tian, Yong

    2015-03-01

    For case carburized steels, electrical conductivity and magnetic permeability profiles are needed to develop model-based case depth characterization techniques for the purpose of nondestructive quality control. To obtain fast and accurate measurement of these material properties, four-point potential drop approaches are applied on circular-shaped discs cut from steel rings with different case depths. First, a direct current potential drop (DCPD) approach is applied to measure electrical conductivity. Subsequently, an alternating current potential drop (ACPD) approach is used to measure magnetic permeability. Practical issues in measurement design and implementation are discussed. Depth profiles of electrical conductivity and magnetic permeability are reported.

  6. Interpreting diel hysteresis between soil respiration and temperature

    Science.gov (United States)

    C. Phillips; N. Nickerson; D. Risk; B.J. Bond

    2011-01-01

    Increasing use of automated soil respiration chambers in recent years has demonstrated complex diel relationships between soil respiration and temperature that are not apparent from less frequent measurements. Soil surface flux is often lagged from soil temperature by several hours, which results in semielliptical hysteresis loops when surface flux is plotted as a...

  7. Small angle neutron scattering measurements of magnetic cluster sizes in magnetic recorging disks

    CERN Document Server

    Toney, M

    2003-01-01

    We describe Small Angle Neutron Scattering measurements of the magnetic cluster size distributions for several longitudinal magnetic recording media. We find that the average magnetic cluster size is slightly larger than the average physical grain size, that there is a broad distribution of cluster sizes, and that the cluster size is inversely correlated to the media signal-to-noise ratio. These results show that intergranular magnetic coupling in these media is small and they provide empirical data for the cluster-size distribution that can be incorporated into models of magnetic recording.

  8. 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.; hide

    2016-01-01

    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.

  9. Magnetic susceptibility measurement using 3D NMR

    Czech Academy of Sciences Publication Activity Database

    Marcon, P.; Bartušek, Karel; Kořínek, Radim

    2011-01-01

    Roč. 24, Suppl. 1 (2011), s. 381-382 ISSN 0968-5243. [ESMRMB 2011 Congress. 06.10.2011-08.10.2011, Leipzig] R&D Projects: GA ČR GAP102/11/0318 Institutional research plan: CEZ:AV0Z20650511 Keywords : MRI * artifact correction * magnetic susceptibility * gradient echo Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  10. High-resolution magnetic measurements of HTSC

    Czech Academy of Sciences Publication Activity Database

    Janů, Zdeněk; Novák, Miloslav; Tsoi, G.

    272-276, - (2004), e1099-e1101 ISSN 0304-8853 R&D Projects: GA ČR GA102/02/0994; GA AV ČR IAA1010104 Institutional research plan: CEZ:AV0Z1010914 Keywords : superconductivity * low-dimensional systems * resonance scattering Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.031, year: 2004

  11. Quadrupole magnetic mapping of the high resolution spectrometers of Thomas Jefferson National Accelerator Laboratory, Hall A. (Q.M.M. project: Quadrupole Magnetic Measurement)

    International Nuclear Information System (INIS)

    Quemener, Gilles

    1997-01-01

    This thesis describes the magnetic measurements that have been performed on the superconducting quadrupoles of the High Resolution Spectrometers of TJNAF, Hall A (USA), which are designed to measure particle momentum up to 4 GeV.c -1 with a σp/p = 10 -4 resolution. The mapping method is based on rotating coil technique, the originality being a segmentation of the probe along the quad axis. Together with an accurate magnet modelling, the measurement of the flux variations through the set of rotating coils allows to determine the magnetic field at each point. We use the 3D field formalism, i.e., the Fourier-Bessel expansion of the field obtained by solving the Laplace equation. We describe the QMM method and then the apparatus consisting in two probes of length 1.6 m and 3.2 m built to map the three quadrupoles Q1, Q2, Q3. Data processing uses Fourier analysis. The mapping of the Electron Arm took place in situ in 1996. A first set of results concerns integral measurements including the properties of excitation cycle of the magnets (saturation and hysteresis). Second set of results in terms of local field yields the 3D field maps of the quadrupoles. After having applied corrections to the data we obtain a local field accuracy of 5 Gauss on each component, i.e. an uncertainty of 5.10 -4 relative to the quadrupole central field. We use SNAKE ray-tracing code with the implementation of QMM field maps and obtain preliminary results on HRS optics. (author)

  12. Application of transient magnetic field to the measurement of nuclear magnetic moments

    International Nuclear Information System (INIS)

    Ribas, R.V.

    1987-01-01

    A review on: the mechanism for producing transient magnetic field; techniques for measuring nuclear gyromagnetic factor; and some examples of recent measurements using this technique is presented. (M.C.K.) [pt

  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. Vibrating wire apparatus for periodic magnetic structure measurement

    International Nuclear Information System (INIS)

    Temnykh, A.B.

    2003-01-01

    Devices with periodic magnetic structures such as wigglers and undulators are often key elements in synchrotron radiation sources. In applications where the coherence of the emitted radiation is important, magnetic field errors distorting the periodicity of the field can significantly reduce the performance of the devices. Thus, the measurement, localization, and correction of the field errors can be a critical issue. This article presents a new method for magnetic field measurements in periodic magnetic structures. The method uses a vibrating taut wire passing through the magnetic structure, and it involves measurements of the amplitudes and phases of the standing waves excited on the wire by the Lorentz force between an AC current in the wire and the surrounding magnetic field. For certain arrangements of the wire, vibrations in the wire will be excited by only non-periodic magnetic field component, i.e., by the error field. By measuring the phase and amplitude of these waves, one can reconstruct the error field distribution and then correct it. The method was tested on a permanent magnet wiggler with 19.8 cm period and a peak field of ∼7000G. It demonstrated ∼0.6G RMS sensitivity, δB rms /B rms ∼1.2x10 -4 and spatial resolution sufficient to identify poles generating the field error. Good agreement was found between field error measurements obtained with the vibrating wire method and with traditional Hall probe field mapping

  15. 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.

  16. Superconducting pulsed magnets

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    Lecture 1. Introduction to Superconducting Materials Type 1,2 and high temperature superconductors; their critical temperature, field & current density. Persistent screening currents and the critical state model. Lecture 2. Magnetization and AC Loss How screening currents cause irreversible magnetization and hysteresis loops. Field errors caused by screening currents. Flux jumping. The general formulation of ac loss in terms of magnetization. AC losses caused by screening currents. Lecture 3. Twisted Wires and Cables Filamentary composite wires and the losses caused by coupling currents between filaments, the need for twisting. Why we need cables and how the coupling currents in cables contribute more ac loss. Field errors caused by coupling currents. Lecture 4. AC Losses in Magnets, Cooling and Measurement Summary of all loss mechanisms and calculation of total losses in the magnet. The need for cooling to minimize temperature rise in a magnet. Measuring ac losses in wires and in magnets. Lecture 5. Stab...

  17. 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.

  18. Phenomenological analysis of thermal hysteresis in Ni-Mn-Ga Heusler alloys

    Science.gov (United States)

    Zagrebin, M. A.; Sokolovskiy, V. V.; Buchelnikov, V. D.

    2018-05-01

    The manipulation of thermal hysteresis in Ni-Mn-Ga Heusler alloys with coupled magnetostructural phase transition is studied theoretically using the Landau theory, including magnetic, elastic and crystal lattice modulation order parameters as well as an external magnetic field. It is shown that for the assigned combination of phenomenological parameters, in the phase diagrams, the Austenite-Martensite first-order phase transition has a finite (critical) point in which the thermal hysteresis is disappeared. Moreover, this point depends on the relation between modulation and elastic constants as well as on the magnetic field. Obtained results have been compared with other theoretical end experimental data.

  19. A Novel Attitude Measurement Algorithm in Magnetic Interference Environment

    Directory of Open Access Journals (Sweden)

    Lingxia Li

    2014-07-01

    Full Text Available The approach of using Magnetic Angular Rate Gravity (MARG sensor for the current multi-sensor based pedestrian navigation algorithm magnetometers is susceptible to the external magnetic interference. The result of attitude is affected by many factors, like the low-precision MEMS gyro drift and large body linear acceleration measurements. In this paper, we propose anti-jamming algorithm which is based on four elements of Extended Kalman Filtering (EKF. To reduce carrier linear acceleration and local magnetic field that impact on attitude measurement, the adaptive covariance matrix structure is considered. Moreover, the heading angle correction threshold method is used in magnetic field compensation and interference environment. Based on the experimental results, the effectiveness of the proposed algorithm suppresses the influence of the external magnetic interference on heading angle, as well as improving the accuracy of system attitude measurement.

  20. High speed pulsed magnetic fields measurements, using the Faraday effect

    International Nuclear Information System (INIS)

    Dillet, A.

    1964-12-01

    For these measures, the information used is the light polarization plane rotation induced by the magnetic field in a glass probe. This rotation is detected using a polarizer-analyzer couple. The detector is a photomultiplier used with high-current and pulsed light. In a distributed magnet (gap: 6 x 3 x 3 cm) magnetic fields to measure are 300 gauss, lasting 0.1 μs, with rise times ≤ 35 ns, repetition rate: 1/s. An oscilloscope is used to view the magnetic field from the P.M. plate signal. The value of the field is computed from a previous static calibration. Magnetic fields from 50 to 2000 gauss (with the probe now used) can be measured to about 20 gauss ± 5 per cent, with a frequency range of 30 MHz. (author) [fr

  1. Hysteresis and compensation behaviors of mixed spin-2 and spin-1 hexagonal Ising nanowire core–shell structure

    Energy Technology Data Exchange (ETDEWEB)

    Masrour, R., E-mail: rachidmasrour@hotmail.com [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, 63 46000 Safi (Morocco); Laboratoire de Magnétisme et Physique des Hautes Energies L.M.P.H.E.URAC 12, Université Mohammed V, Faculté des Sciences, B.P. 1014 Rabat (Morocco); Jabar, A. [Laboratoire de Magnétisme et Physique des Hautes Energies L.M.P.H.E.URAC 12, Université Mohammed V, Faculté des Sciences, B.P. 1014 Rabat (Morocco); Benyoussef, A. [Laboratoire de Magnétisme et Physique des Hautes Energies L.M.P.H.E.URAC 12, Université Mohammed V, Faculté des Sciences, B.P. 1014 Rabat (Morocco); Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Hassan II Academy of Science and Technology, Rabat (Morocco); Hamedoun, M. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Bahmad, L. [Laboratoire de Magnétisme et Physique des Hautes Energies L.M.P.H.E.URAC 12, Université Mohammed V, Faculté des Sciences, B.P. 1014 Rabat (Morocco)

    2015-09-01

    The magnetic behaviors of a mixed spins (2-1) hexagonal Ising nanowire with core–shell structure are investigated by using the Monte Carlo simulations. The thermal magnetizations, the magnetic susceptibilities and the transition temperatures of core–shell are studied for different values of crystal field and exchange interactions. The thermal and magnetic hysteresis cycles are given for different values of the crystal field. - Highlights: • Critical temperature increase when exchange interaction increasing in core-shell. • Hysteresis loop areas decrease at above transition temperature. • Magnetic coercive field decrease when crystal field increasing. • Magnetic coercive field increase when exchange interaction increasing.

  2. Precision Magnet Measurements for X-Band Accelerator Quadrupole Triplets

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, R A; Anderson, S G; Armstrong, J P

    2012-05-16

    An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. Beamline magnets will include an emittance compensation solenoid, windowpane steering dipoles, and quadrupole magnets. Demanding tolerances have been placed on the alignment of these magnets, which directly affects the electron bunch beam quality. A magnet mapping system has been established at LLNL in order to ensure the delivered magnets match their field specification, and the mountings are aligned and capable of reaching the specified alignment tolerances. The magnet measurement system will be described which uses a 3-axis Lakeshore gauss probe mounted on a 3-axis translation stage. Alignment accuracy and precision will be discussed, as well as centering measurements and analysis. The dependence on data analysis over direct multi-pole measurement allows a significant improvement in useful alignment information. Detailed analysis of measurements on the beamline quadrupoles will be discussed, including multi-pole content both from alignment of the magnets, and the intrinsic level of multi-pole magnetic field.

  3. Measuring viscosity with a levitating magnet: application to complex fluids

    International Nuclear Information System (INIS)

    Even, C; Bouquet, F; Deloche, B; Remond, J

    2009-01-01

    As an experimental project proposed to students in fourth year of university, a viscometer was developed, consisting of a small magnet levitating in a viscous fluid. The viscous force acting on the magnet is directly measured: viscosities in the range 10-10 6 mPa s are obtained. This experiment is used as an introduction to complex fluids and soft matter physics

  4. Measuring Viscosity with a Levitating Magnet: Application to Complex Fluids

    Science.gov (United States)

    Even, C.; Bouquet, F.; Remond, J.; Deloche, B.

    2009-01-01

    As an experimental project proposed to students in fourth year of university, a viscometer was developed, consisting of a small magnet levitating in a viscous fluid. The viscous force acting on the magnet is directly measured: viscosities in the range 10-10[superscript 6] mPa s are obtained. This experiment is used as an introduction to complex…

  5. Performance of field measuring probes for SSC magnets

    International Nuclear Information System (INIS)

    Thomas, R.; Ganetis, G.; Herrera, J.; Hogue, R.; Jain, A.; Louie, W.; Marone, A.; Wanderer, P.

    1994-01-01

    Several years of experience have been acquired on the operation of probes (open-quotes molesclose quotes) constructed for the measurement of the multipole components of the magnetic fields of SSC magnets. The field is measured by rotating coils contained in a 2.4-m long tube that is pulled through the aperture of the magnet by an external device - the transporter. In addition to the measuring coils, the tube contains motors for rotating the coil and a system for sensing local vertical using gravity sensors to provide an absolute reference for the field measurements. The authors describe the steps that must be taken in order to ensure accurate, repeatable measurements; the design changes that have been motivated by difficulties encountered (noise, vibration, variations in temperature); and other performance issues. The mechanical interface between the probe and the beam tube of the magnet is also described

  6. Performance of field measuring probes for SSC magnets

    International Nuclear Information System (INIS)

    Thomas, R.; Ganetis, G.; Herrera, J.; Hogue, R.; Jain, A.; Louie, W.; Marone, A.; Wanderer, P.

    1993-01-01

    Several years of experience have been acquired on the operation of probes (''moles'') constructed for the measurement of the multipole components of the magnetic fields of SSC magnets. The field is measured by rotating coils contained in a 2.4-m long tube that is pulled through the aperture of the magnet by an external device-the transporter. In addition to the measuring coils, the tube contains motors for rotating the coil and a system for sensing local vertical using gravity sensors to provide an absolute reference for the field measurements. We describe the steps that must be taken in order to ensure accurate, repeatable measurements; the design changes that have been motivated by difficulties encountered (noise, vibration, variations in temperature); and other performance issues. The mechanical interface between the probe and the hewn tube of the magnet is also described

  7. Hysteresis in the phase transition of chocolate

    Science.gov (United States)

    Ren, Ruilong; Lu, Qunfeng; Lin, Sihua; Dong, Xiaoyan; Fu, Hao; Wu, Shaoyi; Wu, Minghe; Teng, Baohua

    2016-01-01

    We designed an experiment to reproduce the hysteresis phenomenon of chocolate appearing in the heating and cooling process, and then established a model to relate the solidification degree to the order parameter. Based on the Landau-Devonshire theory, our model gave a description of the hysteresis phenomenon in chocolate, which lays the foundations for the study of the phase transition behavior of chocolate.

  8. Hysteresis rarefaction in the Riemann problem

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Pavel

    2008-01-01

    Roč. 138, - (2008), s. 1-10 ISSN 1742-6588. [International Workshop on Multi-Rate Processes and Hysteresis. Cork , 31.03.2008-05.04.2008] Institutional research plan: CEZ:AV0Z10190503 Keywords : Preisach hysteresis * Riemann problem Subject RIV: BA - General Mathematics http://iopscience.iop.org/1742-6596/138/1/012010

  9. Measured longitudinal beam impedance of booster gradient magnets; TOPICAL

    International Nuclear Information System (INIS)

    James L Crisp and Brian J. Fellenz

    2001-01-01

    The Booster gradient magnets have no vacuum pipe which forces the beam image current to flow along the laminated pole tips. Both D and F style magnets were measured with a stretched wire to determine the longitudinal beam impedance caused by these laminations. Results are compared to calculations done 30 years ago. The inductive part of the magnet impedance is interesting because it partially compensates for the negative inductance effects of space charge on the beam. An R/L circuit consisting of 37K(center d ot) in parallel with between 40 and 100uH is a reasonable approximation to the total impedance of Booster magnet laminations

  10. 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

  11. Magnetic field measurement system of the VINCY Cyclotron

    International Nuclear Information System (INIS)

    Dobrosavljevic, A.; Cirkovic, S.; Zdravkovic, A.; Urosevic, Z.; Lucic, M.; Gemaljevic, M.

    1995-01-01

    This paper presents the magnetic field measurement system of the VINCY Cyclotron, main part of the TESLA accelerator installation whose construction has been going on in the Vinca Institute of Nuclear Sciences. Measurement system consists of mechanical structure and control unit for the automatic positioning of the measurement probe in the median plane, between the poles of the magnet, and corresponding measuring instrumentation, based on two digital tesla meters. Concept of the measurement system is defined by the TESLA team, while realisation of the measurement system is performed in co-operation with the LOLA Institute. (author)

  12. Hydrogenation effect on the hysteresis properties of rapidly quenched Nd-Ho-Fe-Co-B alloys

    Czech Academy of Sciences Publication Activity Database

    Tereshina, I.; Kudrevatykh, N.; Tereshina, Evgeniya; Burkhanov, G.; Chistyakov, O.; Grechishkin, R.; Salamova, A.; Verbetsky, V.

    2011-01-01

    Roč. 509, č. 2 (2011), S835-S838 ISSN 0925-8388 Institutional research plan: CEZ:AV0Z10100520 Keywords : rare earth -iron compounds * hydrogenation * coercive field * magnetic hysteresis Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.289, year: 2011

  13. 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.

  14. Perpendicular magnetic anisotropy and the magnetization process in CoFeB/Pd multilayer films

    DEFF Research Database (Denmark)

    Ngo, Duc-The; Quach, Duy-Truong; Hung, Tran Quang

    2014-01-01

    The perpendicular magnetic anisotropy (PMA) and dynamic magnetization-reversal process in [CoFeB t nm/Pd 1.0 nm]n(t = 0.4, 0.6, 0.8, 1.0 and 1.2 nm; n = 2 − 20) multilayer films have been studied by means of magnetic hysteresis and Kerr effect measurements. Strong and controllable PMA with an eff...

  15. Magnetic Measurement Results of the LCLS Undulator Quadrupoles

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Scott; Caban, Keith; Nuhn, Heinz-Dieter; Reese, Ed; Wolf, Zachary; /SLAC

    2011-08-18

    This note details the magnetic measurements and the magnetic center fiducializations that were performed on all of the thirty-six LCLS undulator quadrupoles. Temperature rise, standardization reproducibility, vacuum chamber effects and magnetic center reproducibility measurements are also presented. The Linac Coherent Light Source (LCLS) undulator beam line has 33 girders, each with a LCLS undulator quadrupole which focuses and steers the beam through the beam line. Each quadrupole has main quadrupole coils, as well as separate horizontal and vertical trim coils. Thirty-six quadrupoles, thirty-three installed and three spares were, manufactured for the LCLS undulator system and all were measured to confirm that they met requirement specifications for integrated gradient, harmonics and for magnetic center shifts after current changes. The horizontal and vertical dipole trims of each quadrupole were similarly characterized. Each quadrupole was also fiducialized to its magnetic center. All characterizing measurements on the undulator quads were performed with their mirror plates on and after a standardization of three cycles from -6 to +6 to -6 amps. Since the undulator quadrupoles could be used as a focusing or defocusing magnet depending on their location, all quadrupoles were characterized as focusing and as defocusing quadrupoles. A subset of the undulator quadrupoles were used to verify that the undulator quadrupole design met specifications for temperature rise, standardization reproducibility and magnetic center reproducibility after splitting. The effects of the mirror plates on the undulator quadrupoles were also measured.

  16. Simple optical measurement of the magnetic moment of magnetically labeled objects

    Energy Technology Data Exchange (ETDEWEB)

    Heidsieck, Alexandra, E-mail: aheidsieck@tum.de [Zentralinstitut für Medizintechnik, Technische Universität München (Germany); Rudigkeit, Sarah [Physics Department, Technische Universität München (Germany); Rümenapp, Christine; Gleich, Bernhard [Zentralinstitut für Medizintechnik, Technische Universität München (Germany)

    2017-04-01

    The magnetic moment of magnetically labeled cells, microbubbles or microspheres is an important optimization parameter for many targeting, delivery or separation applications. The quantification of this property is often difficult, since it depends not only on the type of incorporated nanoparticle, but also on the intake capabilities, surface properties and internal distribution. We describe a method to determine the magnetic moment of those carriers using a microscopic set-up and an image processing algorithm. In contrast to other works, we measure the diversion of superparamagnetic nanoparticles in a static fluid. The set-up is optimized to achieve a homogeneous movement of the magnetic carriers inside the magnetic field. The evaluation is automated with a customized algorithm, utilizing a set of basic algorithms, including blob recognition, feature-based shape recognition and a graph algorithm. We present example measurements for the characteristic properties of different types of carriers in combination with different types of nanoparticles. Those properties include velocity in the magnetic field as well as the magnetic moment. The investigated carriers are adherent and suspension cells, while the used nanoparticles have different sizes and coatings to obtain varying behavior of the carriers. - Highlights: • Determination of the magnetic moment of magnetic carriers. • optimized set-up achieve a homogeneous movement. • Automated evaluation with a customized algorithm. • example measurements for the properties of nanoparticle-loaded cells.

  17. Temperature measurement of RE123 bulk superconductors on magnetizing process

    International Nuclear Information System (INIS)

    Yokoyama, K.; Kaneyama, M.; Oka, T.; Fujishiro, H.; Noto, K.

    2004-01-01

    We study on the magnetization behavior of to magnetize RE123 bulk superconductors to apply it as strong magnets. Through magnetizing process, the temperature of bulk superconductors is raised by pinning loss caused by the magnetic fluxes motion (e.g. flux jump of flux flow), and the trapped field is decreased. This paper presents the measurement of temperature changes of Sm123 bulk superconductors during the exciting process by iteratively magnetizing pulsed-field operation with reducing amplitudes (IMRA) method. Five thermocouples are put on the surface of Sm123 bulk superconductor of 46 mm in diameter. The temperatures at the center, on the growth sector boundary (GSB) line and in the sector region surrounded by GSB's line (inter-GSB region) are monitored. The temperature at a cold stage is also measured. A Hall sensor is attached near the center thermocouple to measure the trapped field. After a bulk superconductor is cooled by the GM type refrigerator until 40 K, iterative pulsed-fields of 2.32-5.42 T are applied by a magnetizing coil. When high magnetic field of 5.42 T is applied, a temperature of bulk superconductor reaches to 72.4 K and the magnetic field distribution has C form with which a part of circle is dented, and then, a trapped field is 2.28 T. When a lower magnetic field of 4.64 T is applied, a maximum temperature is 68.3 K and a trapped field is raised to 2.70 T, and moreover, the distribution becomes round shape like field-cooling method (FC). We showed clearly that heat generation by pinning loss was related to the mechanism of magnetic field capture

  18. The insertion device magnetic measurement facility: Prototype and operational procedures

    International Nuclear Information System (INIS)

    Burkel, L.; Dejus, R.; Maines, J.; O'Brien, J.; Vasserman, I.; Pfleuger, J.

    1993-03-01

    This report is a description of the current status of the magnetic measurement facility and is a basic instructional manual for the operation of the facility and its components. Please refer to the appendices for more detailed information about specific components and procedures. The purpose of the magnetic measurement facility is to take accurate measurements of the magnetic field in the gay of the IDs in order to determine the effect of the ID on the stored particle beam and the emitted radiation. The facility will also play an important role when evaluating new ideas, novel devices, and inhouse prototypes as part of the ongoing research and development program at the APS. The measurements will be performed with both moving search coils and moving Hall probes. The IDs will be evaluated by computer modeling of the emitted radiation for any given (measured) magnetic field map. The quality of the magnetic field will be described in terms of integrated multipoles for the effect on Storage Ring performance and in terms of the derived trajectories for the emitted radiation. Before being installed on the Storage Ring, every device will be measured and characterized to assure that it is compatible with Storage Ring requirements and radiation specifications. The accuracy that the APS needs to achieve for magnetic measurements will be based on these specifications

  19. Plastic deformation and hysteresis for hydrogen storage in Pd–Rh alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cappillino, P.J., E-mail: pcappil@sandia.gov [Sandia National Laboratories, PO Box 969, Mail Stop 9292, Livermore, CA 94551 (United States); Lavernia, E.J. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States); Ong, M.D. [Department of Physics, Whitworth University, Spokane, WA 99251 (United States); Wolfer, W.G.; Yang, N.Y. [Sandia National Laboratories, PO Box 969, Mail Stop 9292, Livermore, CA 94551 (United States)

    2014-02-15

    Highlights: • Experimental evidence of plastic work resulting from hydriding of palladium is presented. • A model of this plastic work was generated and correlated to hysteresis losses. • This hysteresis is thought to be important to the lifetime of hydrogen storage materials. • Yield strength values predicted by this model agree with measured hardness. -- Abstract: The hysteresis observed when reversibly absorbing and desorbing hydrogen in metals is currently not fully understood. In general, a hysteresis represents energy that is dissipated during a cycle, but the underlying mechanism of dissipation is still uncertain. It has been suggested that the hysteresis arises either from plastic work, or from elastic strains associated with the accommodation of the hydride phase, or from both. We present here experimental evidence that implicates plastic deformation as the cause of the hysteresis in a Pd–Rh alloy. The plastic work is evident from the increased dislocation density, from the accumulation of surface steps from slip bands, from line broadening of X-ray diffraction peaks, and from an increase in hardness with the number of hydriding cycles. A model of this plastic work is developed that depends on an effective yield strength. When this model is correlated with the measured hysteresis losses, two values are found for the effective yield strength. The lower value is shown to agree with yield strength values derived from Vickers hardness measurements. The hysteresis areas for repeated cycles of absorption and desorption decrease little with the number of cycles which is reminiscent of the plastic deformation hysteresis during low-cycle fatigue of metals. This similarity further confirms the plastic nature of the hydriding hysteresis.

  20. Measuring methods, registration and signal processing for magnetic field research

    International Nuclear Information System (INIS)

    Nagiello, Z.

    1981-01-01

    Some measuring methods and signal processing systems based on analogue and digital technics, which have been applied in magnetic field research using magnetometers with ferromagnetic transducers, are presented. (author)

  1. 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.

  2. Measurement of magnetic fluctuations on ZT-40(M)

    International Nuclear Information System (INIS)

    Miller, G.

    1990-01-01

    The mathematical basis for experimental measurement of magnetic fluctuations in a Reversed Field Pinch is reviewed. A quasi-static drift model is introduced as the frame-work for analysis of the five-fixed-probe technique. The extrapolation of edge-measured rvec B r fluctuations into the plasma is discussed. Correlations between magnetic and other fluctuations expected from a quasi-static model are derived and transport-relevant correlations are discussed. Data from ZT-40(M) are presented

  3. Advances in the measurement of weak magnetic fields

    International Nuclear Information System (INIS)

    Li Damin; Huang Minzhe.

    1992-01-01

    The state-of-art and general features of instruments for measuring weak magnetic fields (such as the non-directional magnetometer, induced coil magnetometer, proton magnetometer, optical pumping magnetometer, flux-gate magnetometer and superconducting quantum magnetometer) are briefly described. Emphasis is laid on the development of a novel technique used in the flux-gate magnetometer and the liquid nitrogen SQUID. Typical applications of the measuring techniques for weak magnetic fields are given

  4. Magnetization measurement of niobium for superconducting cavity material evaluation

    International Nuclear Information System (INIS)

    Wake, Masayoshi; Saito, Kenji.

    1995-05-01

    A series of magnetization measurements on niobium materials for superconducting cavities was performed, and the method was found to be very useful for material evaluation. The effects of annealing, chemical polishing and machining were clearly observed by this method. The material quality and the processing of the material can be properly evaluated by measuring the magnetization. An observation of the Q-disease effect indicates the possibility of using this method for the studies beyond material evaluation. (J.P.N)

  5. Stabilization and Control Models of Systems With Hysteresis Nonlinearities

    Directory of Open Access Journals (Sweden)

    Mihail E. Semenov

    2012-05-01

    Full Text Available Mechanical and economic systems with hysteresis nonlinearities are studied in article. Dissipativity condition of inverted pendulum under the hysteresis control is obtained. The solution of the optimal production strategy problem was found where price has hysteresis behaviour.

  6. Nonlinear control of magnetic signatures

    Science.gov (United States)

    Niemoczynski, Bogdan

    Magnetic properties of ferrite structures are known to cause fluctuations in Earth's magnetic field around the object. These fluctuations are known as the object's magnetic signature and are unique based on the object's geometry and material. It is a common practice to neutralize magnetic signatures periodically after certain time intervals, however there is a growing interest to develop real time degaussing systems for various applications. Development of real time degaussing system is a challenging problem because of magnetic hysteresis and difficulties in measurement or estimation of near-field flux data. The goal of this research is to develop a real time feedback control system that can be used to minimize magnetic signatures for ferrite structures. Experimental work on controlling the magnetic signature of a cylindrical steel shell structure with a magnetic disturbance provided evidence that the control process substantially increased the interior magnetic flux. This means near field estimation using interior sensor data is likely to be inaccurate. Follow up numerical work for rectangular and cylindrical cross sections investigated variations in shell wall flux density under a variety of ambient excitation and applied disturbances. Results showed magnetic disturbances could corrupt interior sensor data and magnetic shielding due to the shell walls makes the interior very sensitive to noise. The magnetic flux inside the shell wall showed little variation due to inner disturbances and its high base value makes it less susceptible to noise. This research proceeds to describe a nonlinear controller to use the shell wall data as an input. A nonlinear plant model of magnetics is developed using a constant tau to represent domain rotation lag and a gain function k to describe the magnetic hysteresis curve for the shell wall. The model is justified by producing hysteresis curves for multiple materials, matching experimental data using a particle swarm algorithm, and

  7. Assessing temporal variations in connectivity through suspended sediment hysteresis analysis

    Science.gov (United States)

    Sherriff, Sophie; Rowan, John; Fenton, Owen; Jordan, Phil; Melland, Alice; Mellander, Per-Erik; hUallacháin, Daire Ó.

    2016-04-01

    Connectivity provides a valuable concept for understanding catchment-scale sediment dynamics. In intensive agricultural catchments, land management through tillage, high livestock densities and extensive land drainage practices significantly change hydromorphological behaviour and alter sediment supply and downstream delivery. Analysis of suspended sediment-discharge hysteresis has offered insights into sediment dynamics but typically on a limited selection of events. Greater availability of continuous high-resolution discharge and turbidity data and qualitative hysteresis metrics enables assessment of sediment dynamics during more events and over time. This paper assesses the utility of this approach to explore seasonal variations in connectivity. Data were collected from three small (c. 10 km2) intensive agricultural catchments in Ireland with contrasting morphologies, soil types, land use patterns and management practices, and are broadly defined as low-permeability supporting grassland, moderate-permeability supporting arable and high-permeability supporting arable. Suspended sediment concentration (using calibrated turbidity measurements) and discharge data were collected at 10-min resolution from each catchment outlet and precipitation data were collected from a weather station within each catchment. Event databases (67-90 events per catchment) collated information on sediment export metrics, hysteresis category (e.g., clockwise, anti-clockwise, no hysteresis), numeric hysteresis index, and potential hydro-meteorological controls on sediment transport including precipitation amount, duration, intensity, stream flow and antecedent soil moisture and rainfall. Statistical analysis of potential controls on sediment export was undertaken using Pearson's correlation coefficient on separate hysteresis categories in each catchment. Sediment hysteresis fluctuations through time were subsequently assessed using the hysteresis index. Results showed the numeric

  8. Internal magnetic turbulence measurement in plasma by cross polarization scattering

    Energy Technology Data Exchange (ETDEWEB)

    Zou, X L; Colas, L; Paume, M; Chareau, J M; Laurent, L; Devynck, P; Gresillon, D

    1994-09-01

    For the first time, the internal magnetic turbulence is measured by a new cross polarization scattering diagnostic in Tore Supra tokamak. The principle of this experiment is presented. It is based on the polarization change or mode conversion of the e.m. wave scattering by magnetic fluctuations. The role of different physical processes on the signal formation are investigated. From the Observation, a rough estimate for the relative magnetic fluctuations of about 10{sup -4} is obtained. A strong correlation of the measured signal with additional heating is observed. (author). 14 refs., 4 figs.

  9. The PVLAS experiment for measuring the magnetic birefringence of vacuum

    International Nuclear Information System (INIS)

    Zavattini, G.; Gastaldi, U.; Messineo, G.; Piemontese, L.; Della Valle, F.; Milotti, E.; Pengo, R.; Ruoso, G.

    2013-01-01

    We describe the principle and status of the PVLAS experiment being prepared at the Department of Physics and INFN section in Ferrara, Italy. The goal of the experiment is to measure the magnetic birefringence of vacuum. This effect is directly connected to the vacuum QED structure and can be detected by measuring the ellipticity acquired by a linearly polarized laser beam traversing a strong magnetic field. Vacuum magnetic birefringence is predicted by the Euler- Heisenberg effective Lagrangian. The experimental method is also sensitive to new physics and could place new laboratory limits to hypothetical particles coupling to two photons, such as axion like particles, or millicharged particles.

  10. 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......, the appearance of life, and its sustainability. The MEMO main platform combined remote sensing and in situ measurements of the atmosphere and the magnetic field during regular incursions into the martian upper atmosphere. The micro-satellite was designed to perform simultaneous in situ solar wind measurements...

  11. 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.

  12. Dual-stage trapped-flux magnet cryostat for measurements at high magnetic fields

    Science.gov (United States)

    Islam, Zahirul; Das, Ritesh K.; Weinstein, Roy

    2015-04-14

    A method and a dual-stage trapped-flux magnet cryostat apparatus are provided for implementing enhanced measurements at high magnetic fields. The dual-stage trapped-flux magnet cryostat system includes a trapped-flux magnet (TFM). A sample, for example, a single crystal, is adjustably positioned proximate to the surface of the TFM, using a translation stage such that the distance between the sample and the surface is selectively adjusted. A cryostat is provided with a first separate thermal stage provided for cooling the TFM and with a second separate thermal stage provided for cooling sample.

  13. Magnetic field measurements and data acquisition of a model magnet for the B-factory

    International Nuclear Information System (INIS)

    Zhou Wenming; Endo, Kuninori

    1994-01-01

    In this paper we describe magnetic field measurements and the field data-acquisition system used to measure the model magnet for the B-factory booster. The results of the measurements indicate that the method adopted here is good for acquiring field data. This type of measurement is highly accurate and involves almost no temperature coefficient. The instrument is used not only for ac, but also dc field measurements. It is especially good for field measurements in the case of simultaneous ac and dc field excitation. (author)

  14. Asymmetrically shaped hysteresis loop in exchange-biased FeNi/FeMn film

    International Nuclear Information System (INIS)

    Gnatchenko, S.L.; Merenkov, D.N.; Bludov, A.N.; Pishko, V.V.; Shakhayeva, Yu.A.; Baran, M.; Szymczak, R.; Novosad, V.A.

    2006-01-01

    The magnetization reversal of the bilayer polycrystalline FeNi(50 A)/FeMn(50 A) film sputtered in a magnetic field has been studied by magnetic and magneto-optical techniques. The external magnetic fields were applied along the easy or hard magnetization axis of the ferromagnetic permalloy layer. The asymmetry of hysteresis loop has been found. Appreciable asymmetry and the exchange bias were observed only in the field applied along the easy axis. The specific features of magnetization reversal were explained within the phenomenological model that involves high-order exchange anisotropy and misalignment of the easy axes of the antiferromagnetic and ferromagnetic layers. It has been shown that the film can exist in one of three equilibrium magnetic states in the field applied along the easy axis. The transitions between these states occur as first-order phase transitions. The observed hysteresis loop asymmetry is related to the existence of the metastable state

  15. 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.

  16. Magnetic Measurements of the Background Field in the Undulator Hall

    International Nuclear Information System (INIS)

    Fisher, Andrew

    2010-01-01

    The steel present in the construction of the undulator hall facility has the potential for changing the ambient fields present in the undulator hall. This note describes a measurement done to make a comparison between the fields in the hall and in the Magnetic Measurement Facility. In order for the undulators to have the proper tuning, the background magnetic field in the Undulator Hall should agree with the background field in the Magnetic Measurements Facility within .5 gauss. In order to verify that this was the case measurements were taken along the length of the undulator hall, and the point measurements were compared to the mean field which was measured on the MMF test bench.

  17. Magnetic field measurements using the transient internal probe (TIP)

    International Nuclear Information System (INIS)

    Galambos, J.P.; Bohnet, M.A.; Jarboe, T.R.; Mattick, A.T.

    1995-01-01

    Knowledge of the internal magnetic field profile in hot plasmas is fundamental to understanding the structure and behavior of the current profile. The transient internal probe (TIP) is a novel diagnostic designed to measure internal magnetic fields in hot plasmas. The diagnostic involves shooting a magneto-optic probe through the plasma at high velocities (greater than 2 km/s) using a two stage light gas gun. Local fields are obtained by illuminating the probe with an argon ion laser and measuring the amount of Faraday rotation in the reflected beam. Initial development of the diagnostic is complete. Results of magnetic field measurements conducted at 2 km/s will be presented. Helium muzzle gas introduction to the plasma chamber has been limited to less than 0.4 Torr-ell. Magnetic field resolution of 40 Gauss and spatial resolution of 5 mm have been achieved. System frequency response is 10 MHz

  18. Magnetic X-ray measurements using the elliptical multipole wiggler

    International Nuclear Information System (INIS)

    Montano, P. A.; Li, Y.; Beno, M. A.; Jennings, G.; Kimball, C. W.

    1999-01-01

    The EMW at the BESSRC beam lines at the APS provides high photon flux at high energies with the capability of producing circular polarization on axis. The authors observe a high degree of circularly polarized x-rays at such energies. The polarization and frequency tunability of the elliptical multipole wiggler (EMW) is an ideal source for many magnetic measurements from X-ray Magnetic Circular Dichroism (XMCD) to Compton scattering experiments. They performed Compton scattering measurements to determine the polarization and photon flux at the sample as a function of the deflection parameters K y and K x . They used for their measurements a Si (220) Laue monochromator providing simultaneous photon energies at 50 keV, 100 keV and 150 keV. Magnetic Compton Profiles were determined by either switching the magnet polarity or the photon helicity. The results obtained using Fe(110) single crystals were very similar

  19. Size dependent thermal hysteresis in spin crossover nanoparticles reflected within a Monte Carlo based Ising-like model

    International Nuclear Information System (INIS)

    Atitoaie, Alexandru; Tanasa, Radu; Enachescu, Cristian

    2012-01-01

    Spin crossover compounds are photo-magnetic bistable molecular magnets with two states in thermodynamic competition: the diamagnetic low-spin state and paramagnetic high-spin state. The thermal transition between the two states is often accompanied by a wide hysteresis, premise for possible application of these materials as recording media. In this paper we study the influence of the system's size on the thermal hysteresis loops using Monte Carlo simulations based on an Arrhenius dynamics applied for an Ising like model with long- and short-range interactions. We show that using appropriate boundary conditions it is possible to reproduce both the drop of hysteresis width with decreasing particle size, the hysteresis shift towards lower temperatures and the incomplete transition, as in the available experimental data. The case of larger systems composed by several sublattices is equally treated reproducing the shrinkage of the hysteresis loop's width experimentally observed. - Highlights: ► A study concerning size effects in spin crossover nanoparticles hysteresis is presented. ► An Ising like model with short- and long-range interactions and Arrhenius dynamics is employed. ► In open boundary system the hysteresis width decreases with particle size. ► With appropriate environment, hysteresis loop is shifted towards lower temperature and transition is incomplete.

  20. Measurement, sorting and tuning of LCLS undulator magnets

    CERN Document Server

    Vasserman, I B; Dejus, Roger J; Moog, E; Trakhtenberg, E; Vinokurov, N A

    2002-01-01

    Currently, a Linac Coherent Light Source (LCLS) prototype undulator is under construction. The prototype is a 3.4-m-long hybrid-type undulator with fixed gap of 6 mm. The period length is 30 mm and the number of poles is 226. For this undulator, 450 NdFeB magnet blocks are used. This project does not have demanding requirements for multipole component errors, but the field strength at x=0 should be as precise as possible to provide proper particle steering and phase errors. The first set of magnetic blocks has been measured. The strength and direction of magnetization of the magnet blocks are measured using a Helmholtz coil system. In addition to this, Hall probe measurements are performed for magnet blocks while they are mounted in a specially designed cassette with vanadium-permendur poles. The magnet blocks will be sorted using these data to minimize errors. Computer simulations show that magnets may be sorted in decreasing strengths with little or no additional tuning of the undulators.

  1. Magnetic measurement of soft magnetic composites material under 3D SVPWM excitation

    Science.gov (United States)

    Zhang, Changgeng; Jiang, Baolin; Li, Yongjian; Yang, Qingxin

    2018-05-01

    The magnetic properties measurement and analysis of soft magnetic material under the rotational space-vector pulse width modulation (SVPWM) excitation are key factors in design and optimization of the adjustable speed motor. In this paper, a three-dimensional (3D) magnetic properties testing system fit for SVPWM excitation is built, which includes symmetrical orthogonal excitation magnetic circuit and cubic field-metric sensor. Base on the testing system, the vector B and H loci of soft magnetic composite (SMC) material under SVPWM excitation are measured and analyzed by proposed 3D SVPWM control method. Alternating and rotating core losses under various complex excitation with different magnitude modulation ratio are calculated and compared.

  2. Serial measurement of relative changes in net magnetization, 1

    International Nuclear Information System (INIS)

    Kaneoke, Yoshiki; Furuse, Masahiro; Izawa, Akira.

    1993-01-01

    We assessed to what extent relative changes in net magnetization could be measured with the low field (0.043 T) MR imager. By the procedure to stabilize the whole MR imager hardware, we could measure the minute relative changes of the net magnetization (less than 1%) from the forearm presumably related to blood volume change. This method may be useful to measure physiological changes of blood volume in various human tissues though we need further development of hardware to measure minute relative changes in MR signal intensity with small volume selection. (author)

  3. 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.

  4. 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

  5. Magnetic fluctuation measurements in the Tokapole II tokamak

    International Nuclear Information System (INIS)

    LaPointe, M.A.

    1990-09-01

    Magnetic fluctuation measurements have been made in the Tokapole II tokamak in the frequency range 10 kHz ≤ f ≤ 5 MHz. The fluctuations above 500 kHz varied greatly as the effective edge safety factor, q a , was varied over the range 0.8 ≤ q a ≤ 3.8. As q a was varied from 3.8 to 0.8 the high frequency magnetic fluctuation amplitude increased by over three orders of magnitude. The fluctuation amplitude for 0.5 to 2.0 MHz was a factor of 10 lower than the fluctuation amplitude in the range 100 to 400 kHz for q a of 0.8. When q a was increased to 3.8 the difference between the differing frequency ranges increased to a factor of 10 3 . Comparison of the measured broadband fluctuation amplitudes with those predicted from thermally driven Alfven and magnetosonic waves shows that the amplitudes are at least 1000 times larger than the theoretical predictions. This indicates that there is some other mechanism driving the higher frequency magnetic fluctuations. Estimates show that the contribution by the magnetic fluctuations above 500 kHz to the estimated electron energy loss from stochastic fields is negligible. The profiles of the various components of the magnetic fluctuations indicate the possibility that the shear in the magnetic field may stabilize whatever instabilities drive the magnetic fluctuations

  6. Modeling and Measurements of Alternating Magnetic Signatures of Ships

    Directory of Open Access Journals (Sweden)

    Zhiqiang Wu

    2015-03-01

    Full Text Available The alternating electric and magnetic fields are new contributors to the global electromagnetic silencing of ships. Thus, modeling and measurements of alternating magnetic signatures should be a research priority in maritime engineering. In this paper, an alternating horizontal electric dipole is adopted to model the electromagnetic fields related with corrosion. Formulas for alternating magnetic fields generated in shallow sea by horizontal electric dipole are derived based on an air-sea-seabed three-layered model and a numerical computer is also applied. In addition, the alternating magnetic fields of a ship are measured using a tri-axis fluxgate magnetometer fixed in a swaying platform. The characteristics of these fields are analyzed. Finally, the equivalent dipole moment of the trial ship is predicted by contrasting the model results and the observed data.

  7. A Superconducting Magnet UCN Trap for Precise Neutron Lifetime Measurements.

    Science.gov (United States)

    Picker, R; Altarev, I; Bröcker, J; Gutsmiedl, E; Hartmann, J; Müller, A; Paul, S; Schott, W; Trinks, U; Zimmer, O

    2005-01-01

    Finite-element methods along with Monte Carlo simulations were used to design a magnetic storage device for ultracold neutrons (UCN) to measure their lifetime. A setup was determined which should make it possible to confine UCN with negligible losses and detect the protons emerging from β-decay with high efficiency: stacked superconducting solenoids create the magnetic storage field, an electrostatic extraction field inside the storage volume assures high proton collection efficiency. Alongside with the optimization of the magnetic and electrostatic design, the properties of the trap were investigated through extensive Monte Carlo simulation.

  8. A magnetic suspension system for measuring liquid density

    Directory of Open Access Journals (Sweden)

    Luz María Centeno González

    2013-01-01

    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.

  9. 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.

  10. Modeling the effect of creep deterioration on magnetic properties in heat-resistant steels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S.Z.; Tu, S.T., E-mail: sttu@ecust.edu.cn

    2014-11-15

    Abstracts: The hysteresis parameters of the Jiles–Atherton model are modified to elucidate the variation of magnetic properties with creep deterioration based on a consideration of the effect of pinning of magnetic domain walls on the grain boundaries, dislocations as well as precipitates in short-term creep process. Experiments are carried out to evaluate the magnetic hysteresis curves of 10CrMo910 specimens with controlled levels of creep-induced damage. An intelligent optimization algorithm is used to determine the hysteresis parameters of Jiles–Atherton model. The microstructure parameters of the crept specimens are determined by a quantitative metallographic analysis. The modified model is applied to correlate the experimental data of both 10CrMo910 and 410 stainless steel creep specimens. The calculated results are in good agreement with the measured data of the hysteresis parameters. - Highlights: • The hysteresis parameters in the Jiles–Atherton model are modified to account for the effect of creep deterioration. • Magnetic properties are greatly affected by the precipitation and dislocations during creep. • Good consistency is obtained between the experimental and theoretical results of hysteresis parameters.

  11. Method and apparatus for measuring nuclear magnetic properties

    Science.gov (United States)

    Weitekamp, Daniel P.; Bielecki, Anthony; Zax, David B.; Zilm, Kurt W.; Pines, Alexander

    1987-01-01

    A method for studying the chemical and structural characteristics of materials is disclosed. The method includes placement of a sample material in a high strength polarizing magnetic field to order the sample nucleii. The condition used to order the sample is then removed abruptly and the ordering of the sample allowed to evolve for a time interval. At the end of the time interval, the ordering of the sample is measured by conventional nuclear magnetic resonance techniques.

  12. Magnetic field measurements of superconducting magnets for the colliding beam accelerator

    International Nuclear Information System (INIS)

    Herrera, J.; Kirk, H.; Prodell, A.; Willen, E.

    1983-01-01

    An important aspect of the development and production of superconducting magnets for the Colliding Beam Accelerator is the measurement of the magnetic field in the aperture of these magnets. The measurements have the three-fold purpose of determining the field quality as compared to the lattice requirements of the CBA, of obtaining the survey data necessary to position the magnets in the CBA tunnel, and lastly, of characterizing the magnetic fields for use in initial and future orbit studies of the CBA proton beams. Since for a superconducting storage accelerator it is necessary to carry out these detailed measurements on many (approx. 1000) magnets and at many current values (approx. 1000), we have chosen, in agreement with previous experience, to develop a system which Fourier analyses the voltages induced in a number of rotating windings and thereby obtains the multipole field components. The important point is that such a measuring system can be fast and precise. It has been used for horizontal measurements of the CBA ring dipoles

  13. Magnetometer for measuring planetary magnetic fields

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Brauer, Peter

    , CHAMP and SAC-C missions. It can produce vector measurements at a rate of 50 Hz and with a precision of more than 21 bits. The thermal and long term stability of the instrument is less than 0.5 nT. The power consumption of the instrument is less than 0.5W for continuous operation. For an orbiting...

  14. Field Measurement of Surface Ship Magnetic Signature Using Multiple AUVs

    Science.gov (United States)

    2009-10-01

    been equipped with a tri-axial fluxgate magnetometer and used to perform preliminary magnetic field measurements. Measurements of this type will be...mounted on the AUVs, shown in Fig. 1, was a three-axis fluxgate type [16] magnetometer with a range of ±100,000 nT and a sensitivity of 100μV/nT. The...surface ship. The system will employ a formation of multiple AUVs, each equipped with a magnetometer . The objective is to measure total magnetic

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. (authors)

  16. Possible hysteresis loops of resonatorless optical bistability

    International Nuclear Information System (INIS)

    Nguyen Ba An; Le Thi Cat Tuong.

    1990-05-01

    We qualitatively show that hysteresis loops of intrinsic optical bistability phenomena without any additional feedback may be of various shapes including those of a butterfly and a three-winged bow. (author). 15 refs, 4 figs

  17. Measurement of 50 Hz magnetic fields in some Norwegian households

    International Nuclear Information System (INIS)

    Karlsen, J.; Johnsson, A.

    1987-01-01

    An examination of 50 Hz magnetic fields has been made in ten different Norwegian dwellings. The aim was to measure the general background level of the 50 Hz magnetic fields. The investigation followed a protocol also used in Swedish measurements, and direct comparisons are therefore possible. A portable, commercial coil instrument was used. In september 1986 and January 1987 the magnetic fields in living rooms, sleeping rooms, and kitchens were measured according to the standardized procedure. Current consumption and temperature at the time of the measurements were also recorded. A clear correlation was noted between the magnetic field values and the current consumption. The mean values of the magnetic fields in the living rooms, sleeping rooms and kitchens, were 12 nT, 11 nT and 160 nT, respectively. The living and sleeping room values can be regarded as very low, and they are much lower than corresponding Swedish values. The kitchen values in the two countries seem, however, to be of the same order of magnitude. The report discusses the need for additional measurements in Norwegian houses

  18. Methods for production of UNK SC-dipoles magnetic measurements

    International Nuclear Information System (INIS)

    Smirnov, N.L.

    1991-01-01

    Many SC-dipoles for UNK will require from the chosen magnetic measurement methods high accuracy and efficiency. The brief of using methods, their possibilities and analysis of their errors are given. The measurements results for a full-scale model of SC-dipole SPDM1 are presented. 5 refs.; 4 figs.; 4 tabs

  19. Automatic magnetic susceptibility measurements between 4 K and 1200 K

    International Nuclear Information System (INIS)

    Raphael, G.

    1969-01-01

    We give a detailed description of a Faraday magnetic susceptibility balance which operates from 4 K to 1200 K. Some preliminary results on platinum and tantalum illustrate the precision and the sensitivity of the measurements. The apparatus has been designed for measurements on the plutonium compounds which present severe health hazards. (author) [fr

  20. Two component butterfly hysteresis in RuSr2EuCeCu2O1 ruthenocuprate

    International Nuclear Information System (INIS)

    Zivkovic, I.; Drobac, D.; Prester, M.

    2006-01-01

    We report detailed studies of the ac susceptibility butterfly hysteresis on the RuSr 2 EuCeCu 2 O 1 (Ru1222) ruthenocuprate compound. Two separate contributions to these hysteresis have been identified and studied. One contribution is ferromagnetic-like and is characterized by the coercive field maximum. Another contribution, represented by the so called inverted maximum, is related to the unusual inverted loops, unique feature of Ru1222 butterfly hysteresis. The different nature of the two identified magnetic contributions is proved by the different temperature dependences involved. By lowering the temperature the inverted peak gradually disappears while the coercive field slowly raises. If the maximum dc field for the hysteresis is increased, the size of the inverted part of the butterfly hysteresis monotonously grows while the position of the peak saturates. In reaching saturation exponential field dependence has been demonstrated to take place. At T = 78 K the saturation field is 42 Oe

  1. Rotational hysteresis and eddy current losses in electrical motor stators under non-conventional supply

    International Nuclear Information System (INIS)

    Bottauscio, Oriano.; Canova, Aldo; Chiampi, Mario; Repetto, Maurizio

    2003-01-01

    The magnetic analysis of stators of electrical motors is performed through an innovative 2D finite element formulation that takes into account the effects of eddy currents within the laminations by means of a generalized constitutive relationship also including vector hysteresis. This approach is applied to a deep estimation of magnetic flux distribution and magnetic losses in stator of induction motors supplied by high-frequency sinusoidal or six-step voltage sources

  2. On some approaches to model reversible magnetization processes

    Science.gov (United States)

    Chwastek, K.; Baghel, A. P. S.; Sai Ram, B.; Borowik, B.; Daniel, L.; Kulkarni, S. V.

    2018-04-01

    This paper focuses on the problem of how reversible magnetization processes are taken into account in contemporary descriptions of hysteresis curves. For comparison, three versions of the phenomenological T(x) model based on hyperbolic tangent mapping are considered. Two of them are based on summing the output of the hysteresis operator with a linear or nonlinear mapping. The third description is inspired by the concept of the product Preisach model. Total susceptibility is modulated with a magnetization-dependent function. The models are verified using measurement data for grain-oriented electrical steel. The proposed third description represents minor loops most accurately.

  3. Cumulative growth of minor hysteresis loops in the Kolmogorov model

    International Nuclear Information System (INIS)

    Meilikhov, E. Z.; Farzetdinova, R. M.

    2013-01-01

    The phenomenon of nonrepeatability of successive remagnetization cycles in Co/M (M = Pt, Pd, Au) multilayer film structures is explained in the framework of the Kolmogorov crystallization model. It is shown that this model of phase transitions can be adapted so as to adequately describe the process of magnetic relaxation in the indicated systems with “memory.” For this purpose, it is necessary to introduce some additional elements into the model, in particular, (i) to take into account the fact that every cycle starts from a state “inherited” from the preceding cycle and (ii) to assume that the rate of growth of a new magnetic phase depends on the cycle number. This modified model provides a quite satisfactory qualitative and quantitative description of all features of successive magnetic relaxation cycles in the system under consideration, including the surprising phenomenon of cumulative growth of minor hysteresis loops.

  4. Measurements of EUV coronal holes and open magnetic flux

    International Nuclear Information System (INIS)

    Lowder, C.; Qiu, J.; Leamon, R.; Liu, Y.

    2014-01-01

    Coronal holes are regions on the Sun's surface that map the footprints of open magnetic field lines. We have developed an automated routine to detect and track boundaries of long-lived coronal holes using full-disk extreme-ultraviolet (EUV) images obtained by SOHO/EIT, SDO/AIA, and STEREO/EUVI. We measure coronal hole areas and magnetic flux in these holes, and compare the measurements with calculations by the potential field source surface (PFSS) model. It is shown that, from 1996 through 2010, the total area of coronal holes measured with EIT images varies between 5% and 17% of the total solar surface area, and the total unsigned open flux varies between (2-5)× 10 22 Mx. The solar cycle dependence of these measurements is similar to the PFSS results, but the model yields larger hole areas and greater open flux than observed by EIT. The AIA/EUVI measurements from 2010-2013 show coronal hole area coverage of 5%-10% of the total surface area, with significant contribution from low latitudes, which is under-represented by EIT. AIA/EUVI have measured much enhanced open magnetic flux in the range of (2-4)× 10 22 Mx, which is about twice the flux measured by EIT, and matches with the PFSS calculated open flux, with discrepancies in the location and strength of coronal holes. A detailed comparison between the three measurements (by EIT, AIA-EUVI, and PFSS) indicates that coronal holes in low latitudes contribute significantly to the total open magnetic flux. These low-latitude coronal holes are not well measured with either the He I 10830 line in previous studies, or EIT EUV images; neither are they well captured by the static PFSS model. The enhanced observations from AIA/EUVI allow a more accurate measure of these low-latitude coronal holes and their contribution to open magnetic flux.

  5. Measurements of EUV coronal holes and open magnetic flux

    Energy Technology Data Exchange (ETDEWEB)

    Lowder, C.; Qiu, J.; Leamon, R. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Liu, Y., E-mail: clowder@solar.physics.montana.edu [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2014-03-10

    Coronal holes are regions on the Sun's surface that map the footprints of open magnetic field lines. We have developed an automated routine to detect and track boundaries of long-lived coronal holes using full-disk extreme-ultraviolet (EUV) images obtained by SOHO/EIT, SDO/AIA, and STEREO/EUVI. We measure coronal hole areas and magnetic flux in these holes, and compare the measurements with calculations by the potential field source surface (PFSS) model. It is shown that, from 1996 through 2010, the total area of coronal holes measured with EIT images varies between 5% and 17% of the total solar surface area, and the total unsigned open flux varies between (2-5)× 10{sup 22} Mx. The solar cycle dependence of these measurements is similar to the PFSS results, but the model yields larger hole areas and greater open flux than observed by EIT. The AIA/EUVI measurements from 2010-2013 show coronal hole area coverage of 5%-10% of the total surface area, with significant contribution from low latitudes, which is under-represented by EIT. AIA/EUVI have measured much enhanced open magnetic flux in the range of (2-4)× 10{sup 22} Mx, which is about twice the flux measured by EIT, and matches with the PFSS calculated open flux, with discrepancies in the location and strength of coronal holes. A detailed comparison between the three measurements (by EIT, AIA-EUVI, and PFSS) indicates that coronal holes in low latitudes contribute significantly to the total open magnetic flux. These low-latitude coronal holes are not well measured with either the He I 10830 line in previous studies, or EIT EUV images; neither are they well captured by the static PFSS model. The enhanced observations from AIA/EUVI allow a more accurate measure of these low-latitude coronal holes and their contribution to open magnetic flux.

  6. Finite magnetic relaxation in x-space magnetic particle imaging: Comparison of measurements and ferrohydrodynamic models.

    Science.gov (United States)

    Dhavalikar, R; Hensley, D; Maldonado-Camargo, L; Croft, L R; Ceron, S; Goodwill, P W; Conolly, S M; Rinaldi, C

    2016-08-03

    Magnetic Particle Imaging (MPI) is an emerging tomographic imaging technology that detects magnetic nanoparticle tracers by exploiting their non-linear magnetization properties. In order to predict the behavior of nanoparticles in an imager, it is possible to use a non-imaging MPI relaxometer or spectrometer to characterize the behavior of nanoparticles in a controlled setting. In this paper we explore the use of ferrohydrodynamic magnetization equations for predicting the response of particles in an MPI relaxometer. These include a magnetization equation developed by Shliomis (Sh) which has a constant relaxation time and a magnetization equation which uses a field-dependent relaxation time developed by Martsenyuk, Raikher and Shliomis (MRSh). We compare the predictions from these models with measurements and with the predictions based on the Langevin function that assumes instantaneous magnetization response of the nanoparticles. The results show good qualitative and quantitative agreement between the ferrohydrodynamic models and the measurements without the use of fitting parameters and provide further evidence of the potential of ferrohydrodynamic modeling in MPI.

  7. A hysteresis phenomenon in NMR spectra of molecular nanomagnets Fe8: a resonant quantum tunneling system

    Science.gov (United States)

    Yamasaki, Tomoaki; Ueda, Miki; Maegawa, Satoru

    2003-05-01

    A molecular nanomagnet Fe8 with a total spin S=10 in the ground state attracts much attention as a substance which exhibits the quantum tunneling of magnetization below 300 mK. We performed 1H NMR measurements for a single crystal of Fe8 in temperature range between 20 and 800 mK. The spectra below 300 mK strongly depend on the sequence of the applied field and those in the positive and negative fields are not symmetric about zero field, while they are symmetric above 300 mK. We discuss the origin of this hysteresis phenomenon, relating to the initial spin state of molecules, the resonant quantum tunneling and the nuclear spin relaxation process.

  8. A hysteresis phenomenon in NMR spectra of molecular nanomagnets Fe8: a resonant quantum tunneling system

    International Nuclear Information System (INIS)

    Yamasaki, Tomoaki; Ueda, Miki; Maegawa, Satoru

    2003-01-01

    A molecular nanomagnet Fe8 with a total spin S=10 in the ground state attracts much attention as a substance which exhibits the quantum tunneling of magnetization below 300 mK. We performed 1 H NMR measurements for a single crystal of Fe8 in temperature range between 20 and 800 mK. The spectra below 300 mK strongly depend on the sequence of the applied field and those in the positive and negative fields are not symmetric about zero field, while they are symmetric above 300 mK. We discuss the origin of this hysteresis phenomenon, relating to the initial spin state of molecules, the resonant quantum tunneling and the nuclear spin relaxation process

  9. Magnetic flux surface measurements at the Wendelstein 7-X stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Otte, Matthias; Andreeva, Tamara; Biedermann, Christoph; Bozhenkov, Sergey; Geiger, Joachim; Sunn Pedersen, Thomas [Max-Planck-Institut fuer Plasmaphysik, Greifswald (Germany); Lazerson, Samuel [Princeton Plasma Physics Laboratory, Princeton (United States)

    2016-07-01

    Recently the first plasma operation phase of the Wendelstein 7-X stellarator has been started at IPP Greifswald. Wendelstein 7-X is an optimized stellarator with a complex superconducting magnet system consisting of 50 non-planar and 20 planar field coils and further 10 normal conducting control and 5 trim coils. The magnetic confinement and hence the expected plasma performance are decisively determined by the properties of the magnet system, especially by the existence and quality of the magnetic flux surfaces. Even small error fields may result in significant changes of the flux surface topology. Therefore, measurements of the vacuum magnetic flux surfaces have been performed before plasma operation. The first experimental results confirm the existence and quality of the flux surfaces to the full extend from low field up to the nominal field strength of B=2.5T. This includes the dedicated magnetic limiter configuration that is exclusively used for the first plasma operation. Furthermore, the measurements are indicating that the intrinsic error fields are within the tolerable range and can be controlled utilizing the trim coils as expected.

  10. 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...

  11. Advanced measurements and techniques in high magnetic fields

    International Nuclear Information System (INIS)

    Campbell, L.J.; Rickel, D.G.; Lacerda, A.H.; Kim, Y.

    1997-01-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). High magnetic fields present a unique environment for studying the electronic structure of materials. Two classes of materials were chosen for experiments at the national high Magnetic Field Laboratory at Los Alamos: highly correlated electron systems and semiconductors. Magnetotransport and thermodynamic experiments were performed on the renormalized ground states of highly correlated electron systems (such as heavy fermion materials and Kondo insulators) in the presence of magnetic fields that are large enough to disrupt the many-body correlations. A variety of optical measurements in high magnetic fields were performed on semiconductor heterostructures including GaAs/AlGaAs single heterojunctions (HEMT structure), coupled double quantum wells (CDQW), asymmetric coupled double quantum wells (ACDQW), multiple quantum wells and a CdTe single crystal thin film

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

    International Nuclear Information System (INIS)

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

    2011-01-01

    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.

  13. Magnetic susceptibility measuring probe utilizing a compensation coil

    International Nuclear Information System (INIS)

    Bonnet, Jean; Fournet, Julien.

    1978-01-01

    This invention concerns a magnetic susceptibility measuring probe. It is used, inter alia, in logging, to wit continuous logging of the magnetic susceptibility of the ground throughout the length of a bore hole. The purpose of this invention is to increase the sensitivity of this type of probe by creating a side focusing effect . To this end, it provides for the use of a compensation winding, coaxial with the measurement winding and arranged symmetrically to the latter with respect to the centre of the induction windings [fr

  14. Synthesis, characterization and magnetic properties of room-temperature nanofluid ferromagnetic graphite

    OpenAIRE

    Souza, N. S.; Sergeenkov, S.; Speglich, C.; Rivera, V. A. G.; Cardoso, C. A.; Pardo, H.; Mombru, A. W.; Rodrigues, A. D.; de Lima, O. F.; Araujo-Moreira, F. M.

    2009-01-01

    We report the chemical synthesis route, structural characterization, and physical properties of nanofluid magnetic graphite (NFMG) obtained from the previously synthesized bulk organic magnetic graphite (MG) by stabilizing the aqueous ferrofluid suspension with an addition of active cationic surfactant. The measured magnetization-field hysteresis curves along with the temperature dependence of magnetization confirmed room-temperature ferromagnetism in both MG and NFMG samples. (C) 2009 Americ...

  15. Magnetization reversal in nucleation controlled magnets. I. Theory

    International Nuclear Information System (INIS)

    Ramesh, R.; Srikrishna, K.

    1988-01-01

    A statistical model, based upon earlier models of Brown [J. Appl. Phys. 33, 3022 (1962)] and McIntyre [J. Phys. D 3, 1430 (1970)] has been developed to examine the magnetization reversal of domain-wall nucleation controlled permanent magnets such as sintered Fe-Nd-B and SmCo 5 . Using a Poisson distribution of the defects on the surface of the grains, a ''weakest link statistics'' type model has been developed. The model has been used to calculate hysteresis loops for sintered Fe-Nd-B-type polycrystalline magnets. It is shown that the intrinsic coercivity measured for a bulk magnet should vary inversely as the logarithm of the surface area of the grain. The effect of demagnetizing field has been incorporated by a mean-field-type approximation, to calculate the overall nucleation field from the intrinsic coercivity. The hysteresis loops theoretically calculated are in excellent agreement with the overall form of those experimentally determined for similar nucleation controlled magnets. The model also predicts that for an inhomogeneous grain size distribution, such as a bimodal distribution, kinks will be observed in the second quadrant of the hysteresis loops

  16. 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.

  17. 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).

  18. Current measurement system utilizing cryogenic techniques for the absolute measurement of the magnetic flux quantum

    International Nuclear Information System (INIS)

    Endo, T.; Murayama, Y.; Sakamoto, Y.; Sakuraba, T.; Shiota, F.

    1989-01-01

    A series of systems composed of cryogenic devices such as a Josephson potentiometer and a cryogenic current comparator has been proposed and developed to precisely measure a current with any value up to 1 A. These systems will be used to measure the injected electrical energy with an uncertainty of the order of 0.01 ppm or less in the absolute measurement of the magnetic flux quantum by superconducting magnetic levitation. Some preliminary experiments are described

  19. High-Precision Hysteresis Sensing of the Quartz Crystal Inductance-to-Frequency Converter.

    Science.gov (United States)

    Matko, Vojko; Milanović, Miro

    2016-06-28

    A new method for the automated measurement of the hysteresis of the temperature-compensated inductance-to-frequency converter with a single quartz crystal is proposed. The new idea behind this method is a converter with two programmable analog switches enabling the automated measurement of the converter hysteresis, as well as the temperature compensation of the quartz crystal and any other circuit element. Also used is the programmable timing control device that allows the selection of different oscillating frequencies. In the proposed programmable method two different inductances connected in series to the quartz crystal are switched in a short time sequence, compensating the crystal's natural temperature characteristics (in the temperature range between 0 and 50 °C). The procedure allows for the measurement of the converter hysteresis at various values of capacitance connected in parallel with the quartz crystal for the converter sensitivity setting at selected inductance. It, furthermore, enables the measurement of hysteresis at various values of inductance at selected parallel capacitance (sensitivity) connected to the quartz crystal. The article shows that the proposed hysteresis measurement of the converter, which converts the inductance in the range between 95 and 100 μH to a frequency in the range between 1 and 200 kHz, has only 7 × 10(-13) frequency instability (during the temperature change between 0 and 50 °C) with a maximum 1 × 10(-11) hysteresis frequency difference.

  20. High-Precision Hysteresis Sensing of the Quartz Crystal Inductance-to-Frequency Converter

    Directory of Open Access Journals (Sweden)

    Vojko Matko

    2016-06-01

    Full Text Available A new method for the automated measurement of the hysteresis of the temperature-compensated inductance-to-frequency converter with a single quartz crystal is proposed. The new idea behind this method is a converter with two programmable analog switches enabling the automated measurement of the converter hysteresis, as well as the temperature compensation of the quartz crystal and any other circuit element. Also used is the programmable timing control device that allows the selection of different oscillating frequencies. In the proposed programmable method two different inductances connected in series to the quartz crystal are switched in a short time sequence, compensating the crystal’s natural temperature characteristics (in the temperature range between 0 and 50 °C. The procedure allows for the measurement of the converter hysteresis at various values of capacitance connected in parallel with the quartz crystal for the converter sensitivity setting at selected inductance. It, furthermore, enables the measurement of hysteresis at various values of inductance at selected parallel capacitance (sensitivity connected to the quartz crystal. The article shows that the proposed hysteresis measurement of the converter, which converts the inductance in the range between 95 and 100 μH to a frequency in the range between 1 and 200 kHz, has only 7 × 10−13 frequency instability (during the temperature change between 0 and 50 °C with a maximum 1 × 10−11 hysteresis frequency difference.

  1. Fitting the flow curve of a plastically deformed silicon steel for the prediction of magnetic properties

    International Nuclear Information System (INIS)

    Sablik, M.J.; Landgraf, F.J.G.; Magnabosco, R.; Fukuhara, M.; Campos, M.F. de; Machado, R.; Missell, F.P.

    2006-01-01

    We report measurements and modelling of magnetic effects due to plastic deformation in 2.2% Si steel, emphasizing new tensile deformation data. The modelling approach is to take the Ludwik law for the strain-hardening stress and use it to compute the dislocation density, which is then used in the computation of magnetic hysteresis. A nonlinear extrapolation is used across the discontinuous yield region to obtain the value of stress at the yield point that is used in fitting Ludwik's law to the mechanical data. The computed magnetic hysteresis exhibits sharp shearing of the loops at small deformation, in agreement with experimental behavior. Magnetic hysteresis loss is shown to follow a Ludwik-like dependence on the residual strain, but with a smaller Ludwik exponent than applies for the mechanical behavior

  2. 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.

  3. Measurement of dielectric and magnetic properties of soil

    International Nuclear Information System (INIS)

    Patitz, W.E.; Brock, B.C.; Powell, E.G.

    1995-11-01

    The possibility of subsurface imaging using SAR technology has generated a considerable amount of interest in recent years. One requirement for the successful development of a subsurface imagin system is an understanding of how the soil affects the signal. In response to a need for an electromagnetic characterization of the soil properties, the Radar/Antenna department has developed a measurement system which determines the soils complex electric permittivity and magnetic permeability at UHF frequencies. The one way loss in dB is also calculated using the measured values. There are many reports of measurements of the electric properties of soil in the literature. However, most of these are primarily concerned with measuring only a real dielectric constant. Because some soils have ferromagnetic constituents it is desirable to measure both the electric and magnetic properties of the soil

  4. Measurement of spectrometric magnet field of EXCHARM setup

    International Nuclear Information System (INIS)

    Aleev, A.N.; Balandin, V.P.; Bordyukov, A.A.

    1998-01-01

    The EXCHARM spectrometer is used for studying charm, strange and exotic hadrons. It is located at the neutron 5N channel of U-70 accelerator (Protvino). The EXCHARM dipole magnet has external size 4.486 x 3.196 x 3.058 m 3 with aperture 2.74 x 0.489 m 2 . The field measurement was made by three-component Hall magnetometer on-line computer in measurement region 2.40 x 0.32 x 3.78 m 3 . The apparatus and methods of the field measuring are described. The results of the measurements of the magnetic field are presented. The estimation of the measurement precision is given. (author)

  5. Measurement of the magnetic field errors on TCV

    International Nuclear Information System (INIS)

    Piras, F.; Moret, J.-M.; Rossel, J.X.

    2010-01-01

    A set of 24 saddle loops is used on the Tokamak a Configuration Variable (TCV) to measure the radial magnetic flux at different toroidal and vertical positions. The new system is calibrated together with the standard magnetic diagnostics on TCV. Based on the results of this calibration, the effective current in the poloidal field coils and their position is computed. These corrections are then used to compute the distribution of the error field inside the vacuum vessel for a typical TCV discharge. Since the saddle loops measure the magnetic flux at different toroidal positions, the non-axisymmetric error field is also estimated and correlated to a shift or a tilt of the poloidal field coils.

  6. A Method for Eddy Current Field Measurement in Permanent Magnet Magnetic Resonance Imaging Systems

    Directory of Open Access Journals (Sweden)

    SONG Rui

    2018-03-01

    Full Text Available Magnetic resonance imaging (MRI is a widely used medical imaging technique. In MRI system, gradient magnetic fields are used to code spatial information. However, the fast-switching electric currents in the gradients coils used to generate gradient fields also induce vortex electric field, often referred as eddy current, in the surrounding metal conductors. In this paper, a method for eddy current field measurement was proposed. Based on the Faraday law of electromagnetic induction, an eddy current field measuring device was designed. Combining hardware acquisition and software processing, the eddy current field was obtained by subtracting the ideal gradient field from the magnetic field measured experimentally, whose waveform could be displayed in real time. The proposed method was verified by experimental results.

  7. Effects of sorption hysteresis on radionuclide releases from waste packages

    International Nuclear Information System (INIS)

    Barney, G.S.; Reed, D.T.

    1985-01-01

    A one-dimensional, numerical transport model was used to calculate radionuclide releases from waste packages emplaced in a nuclear waste repository in basalt. The model incorporates both sorption and desorption isotherm parameters measured previously for sorption of key radionuclides on the packing material component of the waste package. Sorption hysteresis as described by these isotherms lowered releases of some radionuclides by as much as two orders of magnitude. Radionuclides that have low molar inventories (relative to uranium), high solubility, and strongly sorbed, are most affected by sorption hysteresis. In these cases, almost the entire radionuclide inventory is sorbed on the packing material. The model can be used to help optimize the thickness of the packing material layer by comparing release rate versus packing material thickness curves with Nuclear Regulatory Commission (NRC) and Environmental Protection Agency (EPA) release limits

  8. Measurement of the 60 GHz ECR ion source using megawatt magnets - SEISM magnetic field map

    International Nuclear Information System (INIS)

    Marie-Jeanne, M.; Jacob, J.; Lamy, T.; Latrasse, L.; Debray, F.; Matera, J.; Pfister, R.; Trophine, C.

    2012-01-01

    LPSC has developed a 60 GHz Electron Cyclotron Resonance (ECR) Ion Source prototype called SEISM. The magnetic structure uses resistive poly-helix coils designed in collaboration with the French National High Magnetic Fields Facility (LNCMI) to produce a CUSP magnetic configuration. A dedicated test bench and appropriate electrical and water cooling environments were built to study the validity of the mechanics, the thermal behaviour and magnetic field characteristics obtained at various current intensities. During the last months, measurements were performed for several magnetic configurations, with up to 7000 A applied on the injection and extraction coils sets. The magnetic field achieved at 13000 A is expected to allow 28 GHz ECR condition, so by extrapolation 60 GHz should be possible at about 28000 A. However, cavitation issues that appeared around 7000 A are to be solved before carrying on with the tests. This contribution will recall some of the crucial steps in the prototype fabrication, and show preliminary results from the measurements at 7000 A. Possible explanations for the differences observed between the results and the simulation will be given. The paper is followed by the slides of the presentation. (authors)

  9. Magnetization reversal mechanisms in hybrid resin-bonded Nd Fe B magnets

    Science.gov (United States)

    Plusa, D.; Dospial, M.; Slusarek, B.; Kotlarczyk, U.

    2006-11-01

    The magnetic properties of isotropic epoxy resin-bonded magnets prepared by mixing a hard magnetic powder made from melt quenched Nd-Fe-Co-B ribbons and a soft magnetic iron powder have been examined. The magnetization reversal processes and the magnetic parameters have been studied by the measurement of the virgin magnetization curves, the major and minor hysteresis loops and sets of recoil curves. From these recoil curves the field dependence of the reversible and irreversible magnetization components during the magnetization and demagnetization processes has been derived. The remanence relationship was used to study the nature of magnetic interaction between the grains. A study of interaction domains was conducted using optical microscopy. Groups of domains, each over several grains, were observed. It was found that the reversal process in the samples investigated involves the rotation of magnetization vectors in the iron powder grains and pinning of domain walls at the MQP-B grain boundaries.

  10. Magnetization reversal mechanisms in hybrid resin-bonded Nd-Fe-B magnets

    International Nuclear Information System (INIS)

    Plusa, D.; Dospial, M.; Slusarek, B.; Kotlarczyk, U.

    2006-01-01

    The magnetic properties of isotropic epoxy resin-bonded magnets prepared by mixing a hard magnetic powder made from melt quenched Nd-Fe-Co-B ribbons and a soft magnetic iron powder have been examined. The magnetization reversal processes and the magnetic parameters have been studied by the measurement of the virgin magnetization curves, the major and minor hysteresis loops and sets of recoil curves. From these recoil curves the field dependence of the reversible and irreversible magnetization components during the magnetization and demagnetization processes has been derived. The remanence relationship was used to study the nature of magnetic interaction between the grains. A study of interaction domains was conducted using optical microscopy. Groups of domains, each over several grains, were observed. It was found that the reversal process in the samples investigated involves the rotation of magnetization vectors in the iron powder grains and pinning of domain walls at the MQP-B grain boundaries

  11. 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

  12. Faraday Rotation Measure Study of Cluster Magnetic Fields

    Science.gov (United States)

    Frankel, M. M.; Clarke, T. E.

    2001-12-01

    Magnetic fields are thought to play an important role in galaxy cluster evolution. To this end in this study, we looked at polarized radio sources viewed at small impact parameters to the cores of non-cooling flow clusters. By looking at non-cooling flow clusters we hoped to establish what magnetic fields of clusters look like in the absence of the compressed central magnetic fields of the cooling-flow cores. Clarke, Kronberg and Boehringer (2001) examined Faraday rotation measures of radio probes at relatively large impact parameters to the cores of galaxy clusters. The current study is an extension of the Clarke et al. analysis to probe the magnetic fields in the cores of galaxy clusters. We looked at the Faraday rotation of electromagnetic waves from background or imbedded radio galaxies, which were observed with the VLA in A&B arrays. Our results are consistent with previous findings and exhibit a trend towards higher rotation measures and in turn higher magnetic fields at small impact parameters to cluster cores. This research was made possible through funding from the National Science Foundation.

  13. Measurement of Spindle Rigidity by using a Magnet Loader

    Science.gov (United States)

    Yamazaki, Taku; Matsubara, Atsushi; Fujita, Tomoya; Muraki, Toshiyuki; Asano, Kohei; Kawashima, Kazuyuki

    The static rigidity of a rotating spindle in the radial direction is investigated in this research. A magnetic loading device (magnet loader) has been developed for the measurement. The magnet loader, which has coils and iron cores, generates the electromagnetic force and attracts a dummy tool attached to the spindle. However, the eddy current is generated in the dummy tool with the spindle rotation and reduces the attractive force at high spindle speed. In order to understand the magnetic flux and eddy current in the dummy tool, the electromagnetic field analysis by FEM was carried out. Grooves on the attraction surface of the dummy tool were designed to cut the eddy current flow. The dimension of the groove were decided based on the FEM analysis, and the designed tool were manufactured and tested. The test result shows that the designed tool successfully reduces the eddy current and recovers the attractive force. By using the magnet loader and the grooved tool, the spindle rigidity can be measured when the spindle rotates with a speed up to 10,000 min-1.

  14. Magnetic field measurements on board of altitude-research rockets

    International Nuclear Information System (INIS)

    Theile, B.; Luehr, H.

    1976-01-01

    Electric currents within the Earth's magneto- and ionosphere can be probed by measuring their magnetic fields. Different payloads of the national sounding rocket programme will carry magnetometers of high resolution and dynamic range. Thorough test procedures are necessary to evaluate the instrument's properties and possible interference problems. (orig.) [de

  15. The use of magnetic susceptibility measurements to determine ...

    African Journals Online (AJOL)

    This research work presents a study on the application of magnetic susceptibility measurements and geochemical analysis for mapping or assessing heavy metal pollution in the agricultural soil in road proximity. The research work was also done to check any runoff of heavy metals pollution to the Owabi dam which serves ...

  16. Force measurements on a shielded coreless linear permanent magnet motor

    NARCIS (Netherlands)

    Pluk, K.J.W.; Jansen, J.W.; Lomonova, E.A.

    2014-01-01

    This paper compares force measurements on a shielded coreless linear permanent magnet motor with 2-D models. A 2-D semianalytical modeling method is applied, which is based on Fourier modeling and includes force calculations. The semianalytical modeling correctly predicts the behavior found in the

  17. 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…

  18. Triggering for Magnetic Field Measurements of the LCLS Undulators

    Energy Technology Data Exchange (ETDEWEB)

    Hacker, Kirsten

    2010-12-13

    A triggering system for magnetic field measurements of the LCLS undulators has been built with a National Instruments PXI-1002 and a Xylinx FPGA board. The system generates single triggers at specified positions, regardless of encoder sensor jitter about a linear scale.

  19. Triggering for Magnetic Field Measurements of the LCLS Undulators

    International Nuclear Information System (INIS)

    Hacker, Kirsten

    2010-01-01

    A triggering system for magnetic field measurements of the LCLS undulators has been built with a National Instruments PXI-1002 and a Xylinx FPGA board. The system generates single triggers at specified positions, regardless of encoder sensor jitter about a linear scale.

  20. Multiple coil pulsed magnetic resonance method for measuring cold SSC dipole magnet field quality

    International Nuclear Information System (INIS)

    Clark, W.G.; Moore, J.M.; Wong, W.H.

    1990-01-01

    The operating principles and system architecture for a method to measure the magnetic field multipole expansion coefficients are described in the context of the needs of SSC dipole magnets. The operation of an 8-coil prototype system is discussed. Several of the most important technological issues that influence the design are identified and the basis of their resolution is explained. The new features of a 32-coil system presently under construction are described, along with estimates of its requirements for measurement time and data storage capacity

  1. 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

  2. Dynamic properties of micro-magnetic noise in soft ferromagnetic materials

    Science.gov (United States)

    Stupakov, A.; Perevertov, A.

    2018-06-01

    Dynamic response of magnetic hysteresis, magnetic Barkhausen noise and magneto-acoustic emission in a soft ribbon and electrical steels was studied comprehensively. The measurements were performed under controllable magnetization conditions: sinusoidal/triangular waveforms of the magnetic induction and a triangular waveform of the magnetic field. Magnetizing frequency was varied in a wide range: fmag = 0.5 - 500 and 0.5-100 Hz for the ribbon and the electrical steels, respectively. Magnetization amplitude was fixed on a near-saturation level Hmax ≃ 100 A/m. Barkhausen noise signal was detected by a sample-wrapping/surface-mounted coil and differently filtered. It was found that intensity of the Barkhausen noise rises approximately as a square root function of the magnetizing frequency. Whereas, level of the magneto-acoustic emission follows the hysteresis loss trend with an additional linear term (classical loss component).

  3. Hysteresis responses of evapotranspiration to meteorological factors at a diel timescale: patterns and causes.

    Directory of Open Access Journals (Sweden)

    Han Zheng

    Full Text Available Evapotranspiration (ET is an important component of the water cycle in terrestrial ecosystems. Understanding the ways in which ET changes with meteorological factors is central to a better understanding of ecological and hydrological processes. In this study, we used eddy covariance measurements of ET from a typical alpine shrubland meadow ecosystem in China to investigate the hysteresis response of ET to environmental variables including air temperature (Ta, vapor pressure deficit (VPD and net radiation (Rn at a diel timescale. Meanwhile, the simulated ET by Priestly-Taylor equation was used to interpret the measured ET under well-watered conditions. Pronounced hysteresis was observed in both Ta and VPD response curves of ET. At a similar Ta and VPD, ET was always significantly depressed in the afternoon compared with the morning. But the hysteresis response of ET to Rn was not evident. Similar hysteresis patterns were also observed in the Ta/VPD response curves of simulated ET. The magnitudes of the measured and simulated hysteresis loops showed similar seasonal variation, with relatively smaller values occurring from May to September, which agreed well with the lifetime of plants and the period of rainy season at this site. About 62% and 23% of changes in the strength of measured ET-Ta and ET-VPD loops could be explained by the changes in the strength of simulated loops, respectively. Thus, the time lag between Rn and Ta/VPD is the most important factor generating and modulating the ET-Ta/VPD hysteresis, but plants and water status also contribute to the hysteresis response of ET. Our research confirmed the different hysteresis in the responses of ET to meteorological factors and proved the vital role of Rn in driving the diel course of ET.

  4. Correlation measurements of sodium flow rate with magnetic sensors

    International Nuclear Information System (INIS)

    Kebadze, B.V.; Krasnoyarov, N.V.; Adamovskij, L.A.; Golushko, V.V.; Sroelov, V.S.

    1978-01-01

    The results of bench-mark experiments and those carried out at the BOR-60 reactor to measure the sodium coolant flow rate by a correlation method are presented. The method is based on detecting the eddy type flow hydraulic nonuniformities using magnetic flowmeters. The measurements were fulfilled in a broad range of flow rates (G=10-10 4 m 3 /h, Re=2x10 5 -2x10 7 ). The measured and calculated mutual correlation functions are presented with parallel and perpendicular orientations of the flowmeters magnetic fields. A good accord is stated. Prerequirements to the arrangement of the measuring systems are formulated. As an important advantage of the correlation method a possibility of the flowmeter calibration in situ is hydhlighted

  5. 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/...

  6. Effects of the amorphization on hysteresis loops of the amorphous spin-1/2 Ising system

    International Nuclear Information System (INIS)

    Essaoudi, I.; Ainane, A.; Saber, M.; Miguel, J.J. de

    2009-01-01

    We examine the effects of the amorphization on the hysteresis loops of the amorphous spin-1/2 Ising system using the effective field theory within a probability distribution technique that accounts for the self-spin correlation functions. The magnetization, the transverse and longitudinal susceptibilities, and pyromagnetic coefficient are also studied in detail

  7. Hysteresis losses in iron oxide nanoparticles prepared by glass crystallization or wet chemical precipitation

    International Nuclear Information System (INIS)

    Mueller, Robert; Dutz, Silvio; Hergt, Rudolf; Schmidt, Christopher; Steinmetz, Hanna; Zeisberger, Matthias; Gawalek, Wolfgang

    2007-01-01

    Ferrofluids were prepared from glass crystallized as well as wet precipitated iron oxide particles. Comparing hysteresis losses versus applied field amplitude from particles in immobilized state (powder) and in fluid state (ferrofluid) shows in some cases anomalous large losses at low magnetic fields. The influence of texture on the losses was investigated

  8. Quantification of the effect of hysteresis on the adiabatic temperature change in magnetocaloric materials

    DEFF Research Database (Denmark)

    von Moos, Lars; Bahl, Christian R.H.; Nielsen, Kaspar Kirstein

    2014-01-01

    description of the phase transition at varying magnetic fields and temperatures. Using detailed experimental property data, a Preisach type model is used to describe the thermal hysteresis effects and simulate the material under realistic working conditions. We find that the adiabatic temperature change...

  9. Study of vortex configurations in Yb3Rh4Sn13 via minor hysteresis loops

    International Nuclear Information System (INIS)

    Sarkar, S.; Tulapurkar, A.A.; Ramakrishnan, S.; Grover, A.K.; Tomy, C.V.

    2001-01-01

    The tracings of the minor hysteresis loops in the superconductor Yb 3 Rh 4 Sn 13 (i) elucidate the path dependence in J c (H), (ii) help to reach the stable vortex configuration from a given metastable state and (iii) reveal the occurrence of step change in equilibrium magnetization across the peak effect (PE) regime. (author)

  10. Synthesis of Fe3O4 particle-chain microwires in applied magnetic field

    International Nuclear Information System (INIS)

    Li Fashen; Wang Ying; Wang Tao

    2007-01-01

    Fe 3 O 4 particle-chain microwires are firstly synthesized under magnetic field by a simple coprecipitation method. The increase of magnetic field caused the lengthening of the wires, and doubled densities of starting solution lead to a halved diameter. It was supposed that the magnetic field gradient and the particular growing process of particles are the main factors of the formation of these microwires. Magnetic hysteresis curves of Fe 3 O 4 microwires were also measured. - Graphical abstract: Fe 3 O 4 particle-chain microwires are firstly synthesized under magnetic field by a simple coprecipitation method. It was supposed that the magnetic field gradient and the particular growing process of particles are the main factors of the formation of these microwires. Magnetic hysteresis curves of Fe 3 O 4 microwires were also measured

  11. Instrument for the measuring magnetic field characteristics of induction acceleration

    International Nuclear Information System (INIS)

    Novikov, V.M.; Romasheva, P.I.

    1976-01-01

    An instrument for the measuring instantaneous values of variable and pulsed magnetic fields with an amplitide of 0.005-2.0 and duration of 5x10 -6 -2x10 -2 sec is described. Time resolution is not less than 0.5 musec, measuring accuracy is about 1%. Induction coils are used as sensors. A digital voltmeter serves as a secondary recorder

  12. Magnetic moments and lifetime measurements with a piezoelectrically driven plunger

    International Nuclear Information System (INIS)

    Rutten, A.J.

    1980-01-01

    Experiments are described leading to precise values for magnetic dipole moments of excited nuclear states and their mean lifetimes. A plunger system is described especially developed for g-factor and lifetime measurements with the coincidence time-differential recoil-into-vacuum technique. Measurements of the g-factors and lifetimes for the 2 1 + state of 20 O and the 5/2 1 + state of 13 C are described. (Auth.)

  13. Feasibility study of steady state magnetic field measurement

    International Nuclear Information System (INIS)

    Kawahata, Kazuo; Fujita, Junji; Matsuura, Kiyokata; Sakata, Masataka; Fujiwaka, Setsuya; Matoba, Tohru.

    1995-08-01

    A rotating magnetic probe testing system has been designed and constructed for the purpose of establishing a technique of the plasma current measurement on a steady state tokamak. An air turbine is employed to drive the rotating magnetic coil from the viewpoint of avoiding the use of an electric motor in the vicinity of the tokamak device. The signal induced on the rotating probe is transmitted to the amplifier through a transformer coupling. A long term testing on mechanical as well as electrical characteristics has been carried out to find key technical issues on this system. A continuous operation for more than one week has successfully been achieved. (author)

  14. Measuring Magnetic Declination With Compass, GPS and Virtual Globes

    Science.gov (United States)

    O'Brien, W. P.

    2006-12-01

    Using virtual globe (VG) imagery to determine geographic bearing and a compass to determine magnetic bearing yielded acceptable experimental magnetic declination values for large linear physical features at 13 sites in the western continental United States. The geographic bearing of each feature was determined from measurements involving the latitude/longitude coordinate system associated with the VG image (from World Wind or Google Earth). The corresponding magnetic bearing was measured on the ground at the feature with a hand-bearing compass calibrated in 1-degree subdivisions. A sequence of GPS trackpoints, recorded while traveling along the feature either in an automobile or on foot, unambiguously identified the pertinent portion of the feature (a straight segment of a road, for example) when plotted on the VG image. For each physical feature located on a VG image, its geographic bearing was determined directly using on-screen measurement tools available with the VG program or by hand using ruler/protractor methods with printed copies of the VG image. An independent (no use of VG) geographic bearing was also extracted from the slope of a straight-line fit to a latitude/longitude plot of each feature's GPS coordinates, a value that was the same (to within the inherent uncertainty of the data) as the VG-determined bearing, thus validating this procedure for finding geographic bearings. Differences between the VG bearings and the magnetic bearings yielded experimental magnetic declination values within one degree (8 within 0.5 degree) of expected values. From the point of view of physics and geophysics pedagogy, this project affords students a simple magnetism/geodesy field experiment requiring only a good compass and a GPS receiver with memory and a data port. The novel and straightforward data analysis with VG software yields reliable experimental values for an important abstract geophysical quantity, magnetic declination. Just as the compass has long provided

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

    International Nuclear Information System (INIS)

    Smith, Roger J.

    2016-01-01

    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.

  16. 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.

  17. A thermodynamic model of contact angle hysteresis.

    Science.gov (United States)

    Makkonen, Lasse

    2017-08-14

    When a three-phase contact line moves along a solid surface, the contact angle no longer corresponds to the static equilibrium angle but is larger when the liquid is advancing and smaller when the liquid is receding. The difference between the advancing and receding contact angles, i.e., the contact angle hysteresis, is of paramount importance in wetting and capillarity. For example, it determines the magnitude of the external force that is required to make a drop slide on a solid surface. Until now, fundamental origin of the contact angle hysteresis has been controversial. Here, this origin is revealed and a quantitative theory is derived. The theory is corroborated by the available experimental data for a large number of solid-liquid combinations. The theory is applied in modelling the contact angle hysteresis on a textured surface, and these results are also in quantitative agreement with the experimental data.

  18. Hysteresis phenomenon in nuclear reactor dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Pirayesh, Behnam; Pazirandeh, Ali [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Nuclear Engineering, Science and Research Branch; Akbari, Monireh [Shahid Rajaee Teacher Training Univ., Tehran (Iran, Islamic Republic of). Dept. of Mathematics

    2017-05-15

    This paper applies a nonlinear analysis method to show that hysteresis phenomenon, due to the Saddle-node bifurcation, may occur in the nuclear reactor. This phenomenon may have significant effects on nuclear reactor dynamics and can even be the beginning of a nuclear reactor accident. A system of four dimensional nonlinear ordinary differential equations was considered to study the hysteresis phenomenon in a typical nuclear reactor. It should be noted that the reactivity was considered as a nonlinear function of state variables. The condition for emerging hysteresis was investigated using Routh-Hurwitz criterion and Sotomayor's theorem for saddle node bifurcation. A numerical analysis is also provided to illustrate the analytical results.

  19. Dynamic hysteresis of a uniaxial superparamagnet: Semi-adiabatic approximation

    International Nuclear Information System (INIS)

    Poperechny, I.S.; Raikher, Yu.L.; Stepanov, V.I.

    2014-01-01

    The semi-adiabatic theory of magnetic response of a uniaxial single-domain ferromagnetic particle is presented. The approach is developed in the context of the kinetic theory and allows for any orientation of the external field. Within this approximation, the dynamic magnetic hysteresis loops in an ac field are calculated. It is demonstrated that they very closely resemble those obtained by the full kinetic theory. The behavior of the effective coercive force is analyzed in detail, and for it a simple formula is proposed. This relation accounts not only for the temperature behavior of the coercive force, as the previous ones do, but also yields the dependence on the frequency and amplitude of the applied field

  20. 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.

  1. Experimental investigation of the effect of thermal hysteresis in MnFeP1-x Asx materials applied in an AMR device

    DEFF Research Database (Denmark)

    von Moos, Lars; Nielsen, Kaspar Kirstein; Engelbrecht, Kurt

    2012-01-01

    The magnetocaloric material series MnFeP1-xAsx, exhibiting a 1st order phase transition are possibly good candidates for magnetic refrigeration devices operating at room temperature (Brück et al., 2005). These materials have intrinsic hysteresis (thermal and magnetic) and the impact...... (AMR) test device (Bahl et al., 2008) with a flat plate regenerator of a single Curie temperature (TC) material. We find that the maximum adiabatic entropy change does not depend on the thermal history of the material, but the peak temperature is shifted 1.5 K for fields up to 1.5 T when measured...... of this on magnetic refrigeration devices has not yet been thoroughly investigated in the literature. Here, the thermal hysteretic magnetocaloric properties are studied using vibrating sample magnetometry (VSM) and how this influences actual refrigeration performance, using an established active magnetic regenerator...

  2. Origins and mechanisms of hysteresis in organometal halide perovskites

    Science.gov (United States)

    Li, Cheng; Guerrero, Antonio; Zhong, Yu; Huettner, Sven

    2017-05-01

    Inorganic-organic halide organometal perovskites, such as CH3NH3PbI3 and CsPbI3, etc, have been an unprecedented rising star in the field of photovoltaics since 2009, owing to their exceptionally high power conversion efficiency and simple fabrication processability. Despite its relatively short history of development, intensive investigations have been concentrating on this material; these have ranged from crystal structure analysis and photophysical characterization to performance optimization and device integration, etc. Yet, when applied in photovoltaic devices, this material suffers from hysteresis, that is, the difference of the current-voltage (I-V) curve during sweeping in two directions (from short-circuit towards open-circuit and vice versa). This behavior may significantly impede its large-scale commercial application. This Review will focus on the recent theoretical and experimental efforts to reveal the origin and mechanism of hysteresis. The proposed origins include (1) ferroelectric polarization, (2) charge trapping/detrapping, and (3) ion migration. Among them, recent evidence consistently supports the idea that ion migration plays a key role for the hysteretic behavior in perovskite solar cells (PSCs). Hence, this Review will summarize the recent results on ion migration such as the migrating ion species, activation energy measurement, capacitive characterization, and internal electrical field modulation, etc. In addition, this Review will also present the devices with alleviation/elimination of hysteresis by incorporating either large-size grains or phenyl-C61-butyric acid methyl ester molecules. In a different application, the hysteretic property has been utilized in photovoltaic and memristive switching devices. In sum, by examining these three possible mechanisms, it is concluded that the origin of hysteresis in PSCs is associated with a combination of effects, but mainly limited by ion/defect migration. This strong interaction between ion

  3. Hysteresis response of daytime net ecosystem exchange during drought

    Directory of Open Access Journals (Sweden)

    N. Pingintha

    2010-03-01

    Full Text Available Continuous measurements of net ecosystem CO2 exchange (NEE using the eddy-covariance method were made over an agricultural ecosystem in the southeastern US. During optimum environmental conditions, photosynthetically active radiation (PAR was the primary driver controlling daytime NEE, accounting for as much as 67 to 89% of the variation in NEE. However, soil water content became the dominant factor limiting the NEE-PAR response during the peak growth stage. NEE was significantly depressed when high PAR values coincided with very low soil water content. The presence of a counter-clockwise hysteresis of daytime NEE with PAR was observed during periods of water stress. This is a result of the stomatal closure control of photosynthesis at high vapor pressure deficit and enhanced respiration at high temperature. This result is significant since this hysteresis effect limits the range of applicability of the Michaelis-Menten equation and other related expressions in the determination of daytime NEE as a function of PAR. The systematic presence of hysteresis in the response of NEE to PAR suggests that the gap-filling technique based on a non-linear regression approach should take into account the presence of water-limited field conditions. Including this step is therefore likely to improve current evaluation of ecosystem response to increased precipitation variability arising from climatic changes.

  4. 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).

  5. 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).

  6. 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.

  7. A pulse spectrometer for NMR measurements on magnetically ordered materials

    International Nuclear Information System (INIS)

    Englich, J.; Pikner, B.; Sedlak, B.

    1975-01-01

    A simple design of a pulse nuclear magnetic resonance spectrometer is described. The spectrometer permits spin echo measurements on magnetically ordered substances. It operates in the frequency range 10 to 130 MHz, but this basic range can be extended by a replacement of the compact radiofrequency unit. The transmitter gives radiofrequency pulses with an amplitude of up to 1 kV on the coil with the investigated sample. The pulse programmer makes possible relaxation measurements in a time interval of 10 -5 to 10 -1 s. Attention was devoted to obtaining a maximum signal-to-noise ratio in the whole frequency range. Sensitivity of the spectrometer is demonstrated by spin echo measurement on pure iron powder. (author)

  8. 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.

  9. Determination of microturbulence enhanced electron collisionality in magnetized coaxial accelerator channels by direct magnetic field measurement

    International Nuclear Information System (INIS)

    Black, D.C.; Mayo, R.M.; Caress, R.W.

    1997-01-01

    A miniature magnetic probe array, consisting of 10 spatially separated coils, has been used to obtain profile information on the time varying magnetic field within the 2.54 cm wide flow channel of the coaxial plasma source experiment (CPS-1) [R. M. Mayo et al., Plasma Sources Sci. Technol. 4, 47 (1995)]. The magnetic field data have been used, together with a resistive, Hall magnetohydrodynamic (MHD) model of applied field distortion by the flowing plasma, to obtain estimates of the microturbulent enhancement to electron collisionality within the CPS-1 flow channel. These measurements provide direct experimental evidence of anomalous electron collisionality, a previously predicted effect in these devices. The anomaly parameter, a=ν an /ν cl , determined both from the distortion of contours of constant magnetic flux, and from local B θ and B z measurements scales with the classical electron magnetization parameter (Ω cl =ω ce /ν e cl ), indicating that collisionality plays a strong role in determining the level of anomalous transport in the plasma. When this anomaly parameter scaling is cast in terms of the ratio ν e cl /ω lh , it is found that the resistivity enhancement scales with ν e cl /ω lh , and becomes significant at ν e cl /ω lh ≤1, suggesting that a lower hybrid drift instability may be the responsible mechanism for enhanced transport. copyright 1997 American Institute of Physics

  10. Field measuring probe for SSC [Superconducting Super Collider] magnets

    International Nuclear Information System (INIS)

    Ganetis, G.; Herrera, J.; Hogue, R.; Skaritka, J.; Wanderer, P.; Willen, E.

    1987-03-01

    The field probe developed for measuring the field in SSC dipole magnets is an adaptation of the rotating tangential coil system in use at Brookhaven for several years. Also known as the MOLE, it is a self-contained room-temperature mechanism that is pulled through the aperture of the magnet with regular stops to measure the local field. Several minutes are required to measure the field at each point. The probe measures the multipole components of the field as well as the field angle relative to gravity. The sensitivity of the coil and electronics is such that the field up to the full 6.6 T excitation of the magnet as well as the field when warm with only 0.01 T excitation can be measured. Tethers are attached to both ends of the probe to carry electrical connections and to supply dry nitrogen to the air motors that rotate the tangential windings as well as the gravity sensor. A small computer is attached to the probe for control and for data collection, analysis and storage. Digital voltmeters are used to digitize the voltages from the rotating coil and several custom circuits control motor speeds in the probe. The overall diameter of the probe is approximately 2 cm and its length is 2.4 m; the field sensitive windings are 0.6 m in length

  11. Magnetic measurement, sorting optimization and adjustment of SDUV-FEL hybrid undulator

    International Nuclear Information System (INIS)

    Wang Tao; Jia Qika

    2007-01-01

    Construction of an undulator includes magnet block measurement, sorting, field measurement and adjustment. Optimizing SDUV-FEL undulator by simulated annealing algorithm using measurement results of the magnet blocks by Helmholtz coil before installing undulator magnets, the cost function can be reduced by three orders of magnitude. The practical parameters of one segment meet the design specifications after adjusting the magnetic field. (authors)

  12. Equivalent Circuit Modeling of Hysteresis Motors

    Energy Technology Data Exchange (ETDEWEB)

    Nitao, J J; Scharlemann, E T; Kirkendall, B A

    2009-08-31

    We performed a literature review and found that many equivalent circuit models of hysteresis motors in use today are incorrect. The model by Miyairi and Kataoka (1965) is the correct one. We extended the model by transforming it to quadrature coordinates, amenable to circuit or digital simulation. 'Hunting' is an oscillatory phenomenon often observed in hysteresis motors. While several works have attempted to model the phenomenon with some partial success, we present a new complete model that predicts hunting from first principles.

  13. Hysteresis behaviour of soils and rocks

    International Nuclear Information System (INIS)

    Hueckel, T.; Nova, R.

    1979-01-01

    A theory of mechanical hysteresis of geological materials under alternating loading within the yield locus is studied, with emphasis on isotropic pressure sensitivity effects. The hysteresis is described by a 'secant' tensorially linear law which depends on a scalar parameter varying with the advance of the cycle. The constitutive relations are formulated piece-wisely within appropriately conceived stress reversal loci. Specialization to conventional triaxial tests is considered. Finally the feasibility of the model is examined by comparing calculated and actual test data, including those obtained in a cyclic undrained compression test which enlights the phenomenon of cyclic mobility. (orig.)

  14. A Sorption Hysteresis Model For Cellulosic Materials

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Damkilde, Lars

    2006-01-01

    The equilibrium concentration of adsorbed water in cellulosic materials is dependent on the history of the variations of vapor pressure in the ambient air, i.e. sorption hysteresis. Existing models to describe this phenomenon such as the independent domain theory have numerical drawbacks and....../or imply accounting for the entire history variations of every material point. This paper presents a sorption hysteresis model based on a state formulation and expressed in closed-form solutions, which makes it suitable for implementation into a numerical method....

  15. Study on the characteristics of hysteresis loop and resistance of glow discharge plasma using argon gas

    Science.gov (United States)

    Mathew, Prijil; Sajith Mathews, T.; Kurian, P. J.; Chattopadyay, P. K.

    2018-05-01

    Hysteresis in discharge current is produced in a low-pressure, magnetic field free, Glow discharge plasma by varying discharge voltage. The variation in area of the hysteresis loops with pressure, electrode distance and load resistor studied. To understand, the nonlinear behaviour of the I-V characteristics, the changes in gas resistance with electrode voltage, pressure and load resistor were studied. After many trials we propose the best suitable empirical equation for the exponential decrease of the gas resistance with electrode voltage as; R = Rmin + Ae-0.008V, which is a novel one and matches well with our experimental results.

  16. Identification techniques for phenomenological models of hysteresis based on the conjugate gradient method

    International Nuclear Information System (INIS)

    Andrei, Petru; Oniciuc, Liviu; Stancu, Alexandru; Stoleriu, Laurentiu

    2007-01-01

    An identification technique for the parameters of phenomenological models of hysteresis is presented. The basic idea of our technique is to set up a system of equations for the parameters of the model as a function of known quantities on the major or minor hysteresis loops (e.g. coercive force, susceptibilities at various points, remanence), or other magnetization curves. This system of equations can be either over or underspecified and is solved by using the conjugate gradient method. Numerical results related to the identification of parameters in the Energetic, Jiles-Atherton, and Preisach models are presented

  17. Major and minor magnetostriction hysteresis loops of Co-Cu-Ni ferrite

    International Nuclear Information System (INIS)

    Bienkowski, Adam; Kaczkowski, Zbigniew

    2000-01-01

    Initial curve, major and minor magnetostriction hysteresis loops (butterfly loops) as the functions of the static magnetic field of the Co 0.004 Cu 0.12 Ni 0.866 Fe 2.01 O 4.02 ferrite were investigated. The saturation magnetostriction for the field equal to 2500 A/m was negative and equal to -11.1x10 -6 and for the field of 540 A/m (equal to 3H c ) was equal to -8.0x10 -6 . Other minor magnetostriction hysteresis loops are presented

  18. Hysteresis properties of local region of morphous-crystalline alloy. Gisterezisnye svojstva lokal'nogo uchastka amorfnokristallicheskogo splava

    Energy Technology Data Exchange (ETDEWEB)

    Kryukov, I I [Irkutskij Pedagogicheskij Inst., Irkutsk (Russian Federation)

    1991-09-01

    Fields of H{sub 3} domain boundary pinning on an amorphous interlayer d thick, separating neighbouring crystallites, the axes of light magnetization (ALM) of which are disoriented, were calculated by numerical methods for amorpthous-crystalline alloy (ACA). At d=0 and d={infinity} analytical expressions were obtained for H{sub p}. It is shown that ALM dispersion of the crystallites to a considerable extent determines hysteresis properties of ACA and can be responsible for bends on magnetization and remagnetization curves, dependence of hysteresis properties of magnetizing field amplitude and the sample prehistory.

  19. 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

    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...... (MESE) and steady-state free precession free induction decay (SSFP-FID) sequences. Theory and Methods: Considering T1, T2, and T 2 relaxation in the signal-to-noise ratios (SNRs) of the MR magnitude images, the efficiency of MESE and SSFP-FID MREIT experiments, and its dependence on the sequence...

  20. Measurement of time series variation of thermal diffusivity of magnetic fluid under magnetic field by forced Rayleigh scattering method

    Energy Technology Data Exchange (ETDEWEB)

    Motozawa, Masaaki, E-mail: motozawa.masaaki@shizuoka.ac.jp [Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu-shi, Shizuoka 432-8561 (Japan); Muraoka, Takashi [Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu-shi, Shizuoka 432-8561 (Japan); Motosuke, Masahiro, E-mail: mot@rs.tus.ac.jp [Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585 (Japan); Fukuta, Mitsuhiro, E-mail: fukuta.mitsuhiro@shizuoka.ac.jp [Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu-shi, Shizuoka 432-8561 (Japan)

    2017-04-15

    It can be expected that the thermal diffusivity of a magnetic fluid varies from time to time after applying a magnetic field because of the growth of the inner structure of a magnetic fluid such as chain-like clusters. In this study, time series variation of the thermal diffusivity of a magnetic fluid caused by applying a magnetic field was investigated experimentally. For the measurement of time series variation of thermal diffusivity, we attempted to apply the forced Rayleigh scattering method (FRSM), which has high temporal and high spatial resolution. We set up an optical system for the FRSM and measured the thermal diffusivity. A magnetic field was applied to a magnetic fluid in parallel and perpendicular to the heat flux direction, and the magnetic field intensity was 70 mT. The FRSM was successfully applied to measurement of the time series variation of the magnetic fluid from applying a magnetic field. The results show that a characteristic configuration in the time series variation of the thermal diffusivity of magnetic fluid was obtained in the case of applying a magnetic field parallel to the heat flux direction. In contrast, in the case of applying a magnetic field perpendicular to the heat flux, the thermal diffusivity of the magnetic fluid hardly changed during measurement. - Highlights: • Thermal diffusivity was measured by forced Rayleigh scattering method (FRSM). • FRSM has high temporal and high spatial resolutions for measurement. • We attempted to apply FRSM to magnetic fluid (MF). • Time series variation of thermal diffusivity of MF was successfully measured by FRSM. • Anisotropic thermal diffusivity of magnetic fluid was also successfully confirmed.

  1. The effect of surface grain reversal on the AC losses of sintered Nd–Fe–B permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Martina, E-mail: m.moore@ifw-dresden.de [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, 01171 Dresden (Germany); Roth, Stefan; Gebert, Annett [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, 01171 Dresden (Germany); Schultz, Ludwig [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, 01171 Dresden (Germany); TU Dresden, Institute for Materials Science, 01062 Dresden (Germany); Gutfleisch, Oliver [TU Darmstadt, Department of Materials Science, Alarich-Weiß-Str. 16, 64287 Darmstadt (Germany); Fraunhofer Project Group for Materials Recycling and Resource Strategies IWKS, 63457 Hanau (Germany)

    2015-02-01

    Sintered Nd–Fe–B magnets are exposed to AC magnetic fields in many applications, e.g. in permanent magnet electric motors. We have measured the AC losses of sintered Nd–Fe–B magnets in a closed circuit arrangement using AC fields with root mean square-values up to 80 mT (peak amplitude 113 mT) over the frequency range 50 to 1000 Hz. Two magnet grades with different dysprosium content were investigated. Around the remanence point the low grade material (1.7 wt% Dy) showed significant hysteresis losses; whereas the losses in the high grade material (8.9 wt% Dy) were dominated by classical eddy currents. Kerr microscopy images revealed that the hysteresis losses measured for the low grade magnet can be mainly ascribed to grains at the sample surface with multiple domains. This was further confirmed when the high grade material was subsequently exposed to DC and AC magnetic fields. Here a larger number of surface grains with multiple domains are also present once the step in the demagnetization curve attributed to the surface grain reversal is reached and a rise in the measured hysteresis losses is evident. If in the low grade material the operating point is slightly offset from the remanence point, such that zero field is not bypassed, its AC losses can also be fairly well described with classical eddy current theory. - Highlights: • The eddy current losses of sintered Nd–Fe–B magnets were measured. • Field amplitudes up to 113 mT over the frequency range 50 to 1000 Hz were applied. • The Nd–Fe–B magnets showed significant hysteresis losses at low amplitudes (∼100 mT). • The source of such hysteresis losses in sintered Nd–Fe–B magnets was identified. • Two magnet grades with different dysprosium content were investigated.

  2. The effect of surface grain reversal on the AC losses of sintered Nd–Fe–B permanent magnets

    International Nuclear Information System (INIS)

    Moore, Martina; Roth, Stefan; Gebert, Annett; Schultz, Ludwig; Gutfleisch, Oliver

    2015-01-01

    Sintered Nd–Fe–B magnets are exposed to AC magnetic fields in many applications, e.g. in permanent magnet electric motors. We have measured the AC losses of sintered Nd–Fe–B magnets in a closed circuit arrangement using AC fields with root mean square-values up to 80 mT (peak amplitude 113 mT) over the frequency range 50 to 1000 Hz. Two magnet grades with different dysprosium content were investigated. Around the remanence point the low grade material (1.7 wt% Dy) showed significant hysteresis losses; whereas the losses in the high grade material (8.9 wt% Dy) were dominated by classical eddy currents. Kerr microscopy images revealed that the hysteresis losses measured for the low grade magnet can be mainly ascribed to grains at the sample surface with multiple domains. This was further confirmed when the high grade material was subsequently exposed to DC and AC magnetic fields. Here a larger number of surface grains with multiple domains are also present once the step in the demagnetization curve attributed to the surface grain reversal is reached and a rise in the measured hysteresis losses is evident. If in the low grade material the operating point is slightly offset from the remanence point, such that zero field is not bypassed, its AC losses can also be fairly well described with classical eddy current theory. - Highlights: • The eddy current losses of sintered Nd–Fe–B magnets were measured. • Field amplitudes up to 113 mT over the frequency range 50 to 1000 Hz were applied. • The Nd–Fe–B magnets showed significant hysteresis losses at low amplitudes (∼100 mT). • The source of such hysteresis losses in sintered Nd–Fe–B magnets was identified. • Two magnet grades with different dysprosium content were investigated

  3. Vibrating sample magnetometer 2D and 3D magnetization effects associated with different initial magnetization states

    Directory of Open Access Journals (Sweden)

    Ronald E. Lukins

    2017-05-01

    Full Text Available Differences in VSM magnetization vector rotation associated with various initial magnetization states were demonstrated. Procedures and criteria were developed to select sample orientation and initial magnetization states to allow for the combination of two different 2D measurements runs (with the same field profiles to generate a dataset that can be representative of actual 3D magnetization rotation. Nickel, cast iron, and low moment magnetic tape media were used to demonstrate these effects using hysteresis and remanent magnetization test sequences. These results can be used to generate 2D and 3D magnetic properties to better characterize magnetic phenomena which are inherently three dimensional. Example applications are magnetic tape-head orientation sensitivity, reinterpretation of 3D coercivity and other standard magnetic properties, and multi-dimensional shielding effectiveness.

  4. Modelling and measurement of a moving magnet linear compressor performance

    International Nuclear Information System (INIS)

    Liang, Kun; Stone, Richard; Davies, Gareth; Dadd, Mike; Bailey, Paul

    2014-01-01

    A novel moving magnet linear compressor with clearance seals and flexure bearings has been designed and constructed. It is suitable for a refrigeration system with a compact heat exchanger, such as would be needed for CPU cooling. The performance of the compressor has been experimentally evaluated with nitrogen and a mathematical model has been developed to evaluate the performance of the linear compressor. The results from the compressor model and the measurements have been compared in terms of cylinder pressure, the ‘P–V’ loop, stroke, mass flow rate and shaft power. The cylinder pressure was not measured directly but was derived from the compressor dynamics and the motor magnetic force characteristics. The comparisons indicate that the compressor model is well validated and can be used to study the performance of this type of compressor, to help with design optimization and the identification of key parameters affecting the system transients. The electrical and thermodynamic losses were also investigated, particularly for the design point (stroke of 13 mm and pressure ratio of 3.0), since a full understanding of these can lead to an increase in compressor efficiency. - Highlights: • Model predictions of the performance of a novel moving magnet linear compressor. • Prototype linear compressor performance measurements using nitrogen. • Reconstruction of P–V loops using a model of the dynamics and electromagnetics. • Close agreement between the model and measurements for the P–V loops. • The design point motor efficiency was 74%, with potential improvements identified

  5. Tailoring anisotropic magnetoresistance and giant magnetoresistance hysteresis loops with spin-polarized current injection

    International Nuclear Information System (INIS)

    Wegrowe, J.-E.; Kelly, D.; Hoffer, X.; Guittienne, Ph.; Ansermet, J.-Ph.

    2001-01-01

    Current pulses were injected into magnetic nanowires. Their effect on the magnetoresistance hysteresis loops was studied for three morphologies: homogeneous Ni wires, copper wires containing five cobalt/copper bilayers, and hybrid structures composed of a homogeneous Ni half wire and a multilayered Co/Cu half wire. The characteristic features of the action of the current on the magnetization are shown and discussed. [copyright] 2001 American Institute of Physics

  6. Preisach hysteresis implementation in reluctance network method, comparison with finite element method

    OpenAIRE

    Allag , Hicham; Kedous-Lebouc , Afef; Latreche , Mohamed E. H.

    2008-01-01

    International audience; In this work, an implementation of static magnetic hysteresis in the reluctance network method is presented and its effectiveness is demonstrated. This implementation is achieved by a succession of iterative steps in the form of algorithm explained and developed for simple examples. However it remains valid for any magnetic circuit. The results obtained are compared to those given by finite element method simulation and essentially the effect of relaxation is discussed...

  7. A measurement system for two-dimensional DC-biased properties of magnetic materials

    International Nuclear Information System (INIS)

    Enokizono, M.; Matsuo, H.

    2003-01-01

    So far, the DC-biased magnetic properties have been measured in one dimension (scalar). However, these scalar magnetic properties are not enough to clarify the DC-biased magnetic properties because the scalar magnetic properties cannot exactly take into account the phase difference between the magnetic flux density B vector and the magnetic filed strength H vector. Thus, the magnetic field strength H and magnetic flux density B in magnetic materials must be measured as vector quantities (two-dimensional), directly. We showed the measurement system using a single-sheet tester (SST) to clarify the two-dimensional DC-biased magnetic properties. This system excited AC in Y-direction and DC in X-direction. This paper shows the measurement system using an SST and presents the measurement results of two-dimensional DC-biased magnetic properties when changing the DC exciting voltage and the iron loss

  8. Characterization of CHAMP magnetic data anomalies: magnetic contamination and measurement timing

    International Nuclear Information System (INIS)

    Yin, Fan; Cai, Hongtao; Lühr, Hermann; Rauberg, Jan; Michaelis, Ingo

    2013-01-01

    The CHAMP (CHAllenging Minisatellite Payload) mission ended after more than ten years in space on 19 September 2010. For achieving a high measurement accuracy of the magnetometers on CHAMP, detailed analyses of spacecraft magnetic characteristics in orbit are required. A decade of continuous magnetometer and housekeeping data are a good basis for evaluating some of the effects of variable spacecraft magnetic fields on the ambient field determination. It was found that some perturbations of FGM (FluxGate vector Magnetometer) or OVM (OVerhauser scalar Magnetometer) measurements are caused by stray fields induced by the power system, the ASC (advanced stellar compass) instrument or magneto-torquer currents. The magnetic effect of solar currents on FGM measurements varies with the local time of the orbit and amounts to 0.2 nT. In cases when one head of the ASC instrument was blinded by the sun, sometimes transient drops in instrument current strength occur, which were accompanied by magnetic disturbance signals (∼0.3 nT) in FGM measurements. The magnetic residual contamination of OVM data by the torquer currents was of order 0.1 nT but still detectable. An improved torquer correction matrix is derived which eliminates this effect. In-flight scalar calibration parameters revealed some of the effects of timing anomalies. Time lags between FGM and OVM readings are misinterpreted by the scalar calibration as variations of the angles between some of the sensor axes. The resulting amplitudes of the anomalies presented here lie in the range of some 0.1 nT, but they are systematic in nature. (paper)

  9. Macroscopic simulation of isotropic permanent magnets

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. - Highlights: • Simulations of isotropic permanent magnets. • Accurate calculation of remanence magnetization and strayfield. • Comparison with strayfield measurements and anisotropic magnet simulations. • Efficient 3D FEM–BEM coupling for solution of Maxwell equations.

  10. Precise positional measurement system in transcranial magnetic stimulation

    International Nuclear Information System (INIS)

    Inoue, Tomonori; Mishima, Yukuo; Hiwaki, Osamu

    2006-01-01

    Transcranial magnetic stimulation (TMS) is a method for noninvasive stimulation of cerebral cortex, and it has contributed to clinical and basic researches of brain function. In order to estimate the accurate stimulating points of the cortex in TMS, precise measurement of the subject's head and the stimulating coil is necessary. In this study, we have developed the positioning TMS system with a three-dimensional (3-D) digitizer and a multi-articular system. We proposed a method for the accurate measurement of a subject's head and cortex, in which the location data of the subject's face surface captured by a 3-D digitizer were superimposed on the magnetic resonance imaging (MRI) data of the subject's face surface. Using this system, the precise estimation of the stimulated sites of the cortex in TMS was achieved. The validity of the system was verified by the experiment on the TMS of the motor cortex. (author)

  11. Measurements of ground motion and magnets vibrations at the APS

    International Nuclear Information System (INIS)

    Shil'tsev, V.D.

    1994-01-01

    This article presents results of ground motion and magnets vibrations measurements at the Advanced Photon Source. The experiments were done over wide frequency range 0.05-100 Hz with use of SM-3KV type seismic probes from Budker Institute of Nuclear Physics (Russia). Spectral power densities of vertical and horizontal motions of the APS hall floor and quadrupoles on regular supports were obtained. There were also investigated magnets vibrations induced by designed cooling water flow and spectral characteristics of spatial correlation of the quads vibration at different sectors of the ring. Influence of personnel activity in the hall and traffic under the ring on slow motion of storage ring elements were observed. Amplitudes of vibrations at the APS are compared with results of seismic measurements at some other accelerators. 9 refs.; 10 figs.; 1 tab

  12. Measurements of ground motion and magnet vibrations at the APS

    International Nuclear Information System (INIS)

    Shiltsev, V.

    1996-01-01

    This article presents results of ground motion and magnet vibrations measurements at the Advanced Photon Source. The experiments were done over a wide, frequency range (0-05-100 Hz) with the use of SM-3KV-type seismic probes from the Budker Institute of Nuclear Physics (Russia). Spectral power densities of vertical and horizontal motions of the APS hall floor and quadrupoles on regular supports were obtained. Also investigated were magnet vibrations induced by designed cooling water flow and spectral characteristics of spatial correlation of the quadrupole vibrations at different sectors of the ring. The influence of personnel activity in the hall and traffic under the ring on the slow motion of storage ring elements were observed. Amplitudes of vibrations at the APS are compared with results of seismic measurements at some other accelerators

  13. Analysis of a hysteresis motor on asynchronous speed using complex permeability

    International Nuclear Information System (INIS)

    Horii, T.; Yuge, N.; Wakui, G.

    1994-01-01

    Although hysteresis motors have a comparatively small output for their mechanical dimensions compared with other types of motor, they offer the advantages of extremely low vibration and noise levels, and so are widely used as driving motors in acoustic equipment and uranium gas centrifuges. This paper deals with a method for determining the complex permeability in analysis of hysteresis motors. The method assumes that the magnetic intensity distribution is sinusoidal in the direction of rotation. Analysis of the asynchronous speed of a hysteresis motor is then performed for cylindrical coordinates, using modified Bessel functions. The results of calculations are in good agreement with experimental results, confirming the effectiveness of the proposed model and method for determining the complex permeability

  14. Managing Hysteresis: Three Cornerstones to Fiscal Stability

    Science.gov (United States)

    Weeks, Richard

    2012-01-01

    The effects of the Great Recession of 2007-2009 continue to challenge school business officials (SBOs) and other education leaders as they strive to prepare students for the global workforce. Economists have borrowed a word from chemistry to describe this state of affairs: hysteresis--the lingering effects of the past on the present. Today's SBOs…

  15. Hysteresis and transition in swirling nonpremixed flames

    NARCIS (Netherlands)

    Tummers, M.J.; Hübner, A.W.; van Veen, E.H.; Hanjalic, K.; van der Meer, Theodorus H.

    2009-01-01

    Strongly swirling nonpremixed flames are known to exhibit a hysteresis when transiting from an attached long, sooty, yellow flame to a short lifted blue flame, and vice versa. The upward transition (by increasing the air and fuel flow rates) corresponds to a vortex breakdown, i.e. an abrupt change

  16. The hysteresis limit in relaxation oscillation problems

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Pavel

    2005-01-01

    Roč. 22, - (2005), s. 103-123 ISSN 1742-6588. [International Workshop on Hysteresis & Multi-scale Asymptotic. Cork , 17.3.2004-21.3.2004] Institutional research plan: CEZ:AV0Z1019905 Keywords : Helly principle * differential equation Subject RIV: BA - General Mathematics http://iopscience.iop.org/1742-6596/22/1/007

  17. Weak differentiability of scalar hysteresis operators

    Czech Academy of Sciences Publication Activity Database

    Brokate, M.; Krejčí, Pavel

    2015-01-01

    Roč. 35, č. 6 (2015), s. 2405-2421 ISSN 1078-0947 R&D Projects: GA ČR GAP201/10/2315 Institutional support: RVO:67985840 Keywords : hysteresis * differentiability * variational inequality Subject RIV: BA - General Mathematics Impact factor: 1.127, year: 2015 http://www.aimsciences.org/journals/displayArticlesnew.jsp?paperID=10677

  18. Numerical and experimental comparison of electromechanical properties and efficiency of HTS and ferromagnetic hysteresis motors

    International Nuclear Information System (INIS)

    Inacio, D; Inacio, S; Pina, J; Goncalves, A; Neves, M Ventim; Rodrigues, A Leao

    2008-01-01

    Hysteresis motors are very attractive in a wide range of fractional power applications, due to its torque-speed characteristics and simplicity of construction. This motor's performance is expected to improve when HTS rotors are used, and in fact, hysteresis motors have shown to be probably the most viable electrical machines using HTS materials. While these motors, either conventional or HTS, are both hysteresis motors, they base their operation on different physical phenomena: hysteretic behaviour in conventional ferromagnetic materials is due to the material's non-linear magnetic properties, while in HTS materials the hysteresis has an ohmic nature and is related with vortices' dynamics. In this paper, theoretical aspects of both conventional and HTS hysteresis motors are discussed, its operation principles are highlighted, and the characteristics of both motors are presented. The characteristics, obtained both by experimental tests and numerical simulation (made with commercial software), are compared, in order to evaluate not only the motor's electromechanical performances but also the overall systems efficiency, including cryogenics for the HTS device

  19. 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,...

  20. Kerr microscopy study of exchange-coupled FePt/Fe exchange spring magnets

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Zaineb; Kumar, Dileep [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Reddy, V. Raghavendra, E-mail: varimalla@yahoo.com [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Gupta, Ajay [Amity Center for Spintronic Materials, Amity University, Noida 201303 (India)

    2017-05-15

    Magnetization reversal and magnetic microstructure of top soft magnetic layer (Fe) in exchange spring coupled L1{sub 0} FePt/Fe is studied using high resolution Kerr microscopy. With remnant state of the hard magnetic layer (L1{sub 0} FePt) as initial condition, magnetization loops along with magnetic domains are recorded for the top soft magnetic layer (Fe) using Kerr microscopy. Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. It is also observed that one can tune the magnitude of hysteresis shift by reaching the remanent state from different saturating fields (H{sub SAT}) and also by varying the angle between measuring field and H{sub SAT}. The hysteresis loops and magnetic domains of top soft Fe layer demonstrate unambiguously that soft magnetic layer at remanent state in such exchange coupled system is having unidirectional anisotropy. An analogy is drawn and the observations are explained in terms of established model of exchange bias phenomena framed for field-cooled ferromagnetic - antiferromagnetic bilayer systems. - Highlights: • Kerr microscopy of top soft magnetic Fe layer in exchange spring coupled L1{sub 0} FePt (30 nm)/Fe (22 nm) is reported. • Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. • Tuneable nature of magnitude of hysteresis shift is shown. • It is unambiguously shown that the top soft Fe magnetic layer at remanent state is having unidirectional anisotropy.