WorldWideScience

Sample records for method magnetic studies

  1. [Gastric magnetic resonance study (methods, semiotics)].

    Science.gov (United States)

    Stashuk, G A

    2003-01-01

    The paper shows the potentialities of gastric study by magnetic resonance imaging (MRI). The methodic aspects of gastric study have been worked out. The MRI-semiotics of the unchanged and tumor-affected wall of the stomach and techniques in examining patients with gastric cancer of various sites are described. Using the developed procedure, MRI was performed in 199 patients, including 154 patients with gastric pathology and 45 control individuals who had no altered gastric wall. Great emphasis is placed on the role of MRI in the diagnosis of endophytic (diffuse) gastric cancer that is of priority value in its morphological structure. MRI was found to play a role in the diagnosis of the spread of a tumorous process both along the walls of the stomach and to its adjacent anatomic structures.

  2. Methods for studying plasma charge transport across a magnetic field

    International Nuclear Information System (INIS)

    Popovich, A.S.

    1978-01-01

    A comparative analysis of experimental methods for the diffusion transfer of plasma charged particles accross the magnetic field at the study of its confinement effectiveness, instability effect is carried out. Considered are the methods based on the analysis of particle balance in the charge and possibilities of diffusion coefficient determination according to measuring parameters of density gradient and particle flow on the wall, rate of plasma decay after switching off ionization source radial profile of plasma density outside the active region of stationary charge. Much attension is payed to the research methods of diffusion transfer, connected with the study of propagation of periodic and aperiodic density perturbation in a plasma. Analysed is the Golubev and Granovsky method of diffusion waves and its different modifications, phase analysis method of ''test charges'' movement, as well as different modifications of correlation methods. Considered are physical preconditions of the latter and criticized is unilateral interpretation of correlation measurings, carried out in a number of works. The analysis of study possibilities of independent (non-ambipolar) diffusion of electrons and ions in a plasma in the magnetic field is executed

  3. A new polarized neutrons method for studying depth-inhomogeneously magnetized magnetic films

    International Nuclear Information System (INIS)

    Korneev, D.A.

    1990-01-01

    The main specific features of the process of polarized thermal neutrons specular reflection from the surface of depth-inhomogeneously magnetic films are considered theoretically. It is shown how using the method of specular reflection of polarized thermal neutrons from such a films surface, one may restore the depth distribution of the local magnetization vector M-vector(z). 9 refs

  4. Transport Studies of Quantum Magnetism: Physics and Methods

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Minhyea [Univ. of Colorado, Boulder, CO (United States)

    2017-03-30

    The main goal of this project was to understand novel ground states of spin systems probed by thermal and electrical transport measurements. They are well-suited to characterize the nature of low-energy excitations as unique property of the ground state. More specifically, it was aimed to study the transverse electrical conductivity in the presence of non-collinear and non-coplanar spin ordering and the effects of gauge field as well as novel spin excitations as a coherent heat transport channel in insulating quantum magnets. Most of works done during the grant period focused on these topics. As a natural extension of the project's initial goals, the scope was broadened to include transport studies on the spin systems with strong spin-orbit coupling. One particular focus was an exploration of systems with strong magnetic anisotropy combined with non-trivial spin configuration. Magnetic anisotropy is directly related to implement the non-collinear spin ordering to the existing common geometry of planar devices and thus poses a significant potential. Work in this direction includes the comparison of the topological Hall signal under hydrostatic pressure and chemical doping, as well as the angular dependence dependence of the non-collinear spin ordered phase and their evolution up on temperature and field strength. Another focus was centered around the experimental identification of spin-originated heat carrying excitation in quasi two dimensional honeycomb lattice, where Kitaev type of quantum spin liquid phase is expected to emerge. In fact, when its long range magnetic order is destroyed by the applied field, we discovered anomalously large enhancement of thermal conductivity, for which proximate Kitaev excitations in field-induced spin liquid state are responsible for. This work, combined with further investigations in materials in the similar class may help establish the experimental characterization of new quantum spin liquid and their unique low energy

  5. Spectral methods for study of the G-protein-coupled receptor rhodopsin. II. Magnetic resonance methods

    Science.gov (United States)

    Struts, A. V.; Barmasov, A. V.; Brown, M. F.

    2016-02-01

    This article continues our review of spectroscopic studies of G-protein-coupled receptors. Magnetic resonance methods including electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) provide specific structural and dynamical data for the protein in conjunction with optical methods (vibrational, electronic spectroscopy) as discussed in the accompanying article. An additional advantage is the opportunity to explore the receptor proteins in the natural membrane lipid environment. Solid-state 2H and 13C NMR methods yield information about both the local structure and dynamics of the cofactor bound to the protein and its light-induced changes. Complementary site-directed spin-labeling studies monitor the structural alterations over larger distances and correspondingly longer time scales. A multiscale reaction mechanism describes how local changes of the retinal cofactor unlock the receptor to initiate large-scale conformational changes of rhodopsin. Activation of the G-protein-coupled receptor involves an ensemble of conformational substates within the rhodopsin manifold that characterize the dynamically active receptor.

  6. A study of an active magnetic shielding method for the superconductive Maglev vehicle

    International Nuclear Information System (INIS)

    Nemoto, K.; Komori, M.

    2010-01-01

    Various methods of magnetic shielding have been studied so far to reduce magnetic field strength inside the passenger room of the superconductive Maglev vehicle. Magnetic shielding methods with ferromagnetic materials are very useful, but they tend to be heavier for large space. Though some passive magnetic shielding methods using induced currents in superconducting bulks or superconducting coils have also been studied, the induced current is relatively small and it is difficult to get satisfactory magnetic shielding performance for the passenger room of the Maglev vehicle. Thus, we have proposed an active magnetic shielding method with some superconducting coils of the same length as propulsion-levitation-guidance superconducting coils of the Maglev vehicle. They are arranged under the passenger room of the Maglev vehicle. Then, we studied the shielding effect by canceling magnetic flux density in the passenger room by way of adjusting magnetomotive-forces of the magnetic shielding coils. As a result, it is found that a simple arrangement of two magnetic shielding coils for one propulsion-levitation-guidance superconducting coil on the vehicle shows an effective magnetic shielding.

  7. A study of an active magnetic shielding method for the superconductive Maglev vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Nemoto, K., E-mail: nemoto@kamakuranet.ne.j [Kyushu Institute of Technology, Dept. of Applied Science for Integrated System Engineering, 1-1 Sensui, Tobata, Kitakyushu, Fukuoka 804-8550 (Japan); Komori, M. [Kyushu Institute of Technology, Dept. of Applied Science for Integrated System Engineering, 1-1 Sensui, Tobata, Kitakyushu, Fukuoka 804-8550 (Japan)

    2010-11-01

    Various methods of magnetic shielding have been studied so far to reduce magnetic field strength inside the passenger room of the superconductive Maglev vehicle. Magnetic shielding methods with ferromagnetic materials are very useful, but they tend to be heavier for large space. Though some passive magnetic shielding methods using induced currents in superconducting bulks or superconducting coils have also been studied, the induced current is relatively small and it is difficult to get satisfactory magnetic shielding performance for the passenger room of the Maglev vehicle. Thus, we have proposed an active magnetic shielding method with some superconducting coils of the same length as propulsion-levitation-guidance superconducting coils of the Maglev vehicle. They are arranged under the passenger room of the Maglev vehicle. Then, we studied the shielding effect by canceling magnetic flux density in the passenger room by way of adjusting magnetomotive-forces of the magnetic shielding coils. As a result, it is found that a simple arrangement of two magnetic shielding coils for one propulsion-levitation-guidance superconducting coil on the vehicle shows an effective magnetic shielding.

  8. Study on control method of running velocity for the permanent magnet-HTSC hybrid magnetically levitated conveyance system

    International Nuclear Information System (INIS)

    Nishio, R.; Ikeda, M.; Sasaki, R.; Ohashi, S.

    2011-01-01

    The hybrid magnetically levitated carrying system is developed. Control method of running velocity of the carrier is studied. Running velocity is controlled by current of the propulsion coils. Propulsion characteristcs are improved. We have developed the magnetically levitated carrying system. In this system, pinning force of high temperature bulk super conductor (HTSC) is used for the levitation and guidance. Four HTSCs are installed on the carrier. The magnetic rail is set on the ground, and flux from the magnetic rail is pinned by HTSCs. To increase levitation force, repulsive force of the permanent magnet is used. The hybrid levitation system is composed. The permanent magnet is installed under the load stage of the carrier. Repulsive force by the permanent magnet between the load stage on the carrier and the magnetic rail on the ground is used to support the load weight. Levitation and guidance one by pinning effect of the YBaCuO HTSC in the carrier is used to levitate the carrier body. The load stage is separated from the carrier flame and can move freely for vertical direction levitation. For the propulsion system, electromagnet is installed on the surface of the magnetic rail. In this paper, control method of running velocity of the carrier is studied. Propulsion force is given as follows; Air core copper coils are installed on the magnetic rail. Interaction between current of these coils and permanent magnets on the carrier generates propulsion force. Running velocity is controlled by current of the propulsion coils. It is also changed by position of the carrier and the load weight. From the results, stability of the propulsion system is given, and propulsion characteristics are improved.

  9. Study on control method of running velocity for the permanent magnet-HTSC hybrid magnetically levitated conveyance system

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, R.; Ikeda, M.; Sasaki, R. [Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan); Ohashi, S., E-mail: ohashi@kansai-u.ac.jp [Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan)

    2011-11-15

    The hybrid magnetically levitated carrying system is developed. Control method of running velocity of the carrier is studied. Running velocity is controlled by current of the propulsion coils. Propulsion characteristcs are improved. We have developed the magnetically levitated carrying system. In this system, pinning force of high temperature bulk super conductor (HTSC) is used for the levitation and guidance. Four HTSCs are installed on the carrier. The magnetic rail is set on the ground, and flux from the magnetic rail is pinned by HTSCs. To increase levitation force, repulsive force of the permanent magnet is used. The hybrid levitation system is composed. The permanent magnet is installed under the load stage of the carrier. Repulsive force by the permanent magnet between the load stage on the carrier and the magnetic rail on the ground is used to support the load weight. Levitation and guidance one by pinning effect of the YBaCuO HTSC in the carrier is used to levitate the carrier body. The load stage is separated from the carrier flame and can move freely for vertical direction levitation. For the propulsion system, electromagnet is installed on the surface of the magnetic rail. In this paper, control method of running velocity of the carrier is studied. Propulsion force is given as follows; Air core copper coils are installed on the magnetic rail. Interaction between current of these coils and permanent magnets on the carrier generates propulsion force. Running velocity is controlled by current of the propulsion coils. It is also changed by position of the carrier and the load weight. From the results, stability of the propulsion system is given, and propulsion characteristics are improved.

  10. High-order coupled cluster method study of frustrated and unfrustrated quantum magnets in external magnetic fields

    International Nuclear Information System (INIS)

    Farnell, D J J; Zinke, R; Richter, J; Schulenburg, J

    2009-01-01

    We apply the coupled cluster method (CCM) in order to study the ground-state properties of the (unfrustrated) square-lattice and (frustrated) triangular-lattice spin-half Heisenberg antiferromagnets in the presence of external magnetic fields. Approximate methods are difficult to apply to the triangular-lattice antiferromagnet because of frustration, and so, for example, the quantum Monte Carlo (QMC) method suffers from the 'sign problem'. Results for this model in the presence of magnetic field are rarer than those for the square-lattice system. Here we determine and solve the basic CCM equations by using the localized approximation scheme commonly referred to as the 'LSUBm' approximation scheme and we carry out high-order calculations by using intensive computational methods. We calculate the ground-state energy, the uniform susceptibility, the total (lattice) magnetization and the local (sublattice) magnetizations as a function of the magnetic field strength. Our results for the lattice magnetization of the square-lattice case compare well to the results from QMC approaches for all values of the applied external magnetic field. We find a value for the magnetic susceptibility of χ = 0.070 for the square-lattice antiferromagnet, which is also in agreement with the results from other approximate methods (e.g., χ = 0.0669 obtained via the QMC approach). Our estimate for the range of the extent of the (M/M s =) 1/3 magnetization plateau for the triangular-lattice antiferromagnet is 1.37 SWT = 0.0794. Higher-order calculations are thus suggested for both SWT and CCM LSUBm calculations in order to determine the value of χ for the triangular lattice conclusively.

  11. [The method for studying of the "magnetic vacuum" effect on color memory in humans].

    Science.gov (United States)

    Bingi, V N; Zarutskiĭ, A A; Kapranov, S V; Kotel'nikov, S N; Miliaev, V A; Sarimov, R M

    2005-01-01

    The method for studying the effects of weak magnetic fields and "magnetic vacuum" on the psychophysiological state of a human organism is proposed. This method includes the system of the exposure of a human organism to uniform constant and alternating magnetic fields and the system of computerized psychological tests. The influence of the weakening of constant magnetic field on the psychophysiological state of human organisms was studied. The short-term color memory and reaction rates of 30 subjects have been examined in the local geomagnetic field and in a magnetic field which was reduced in 10 and more times. Statistically significant differences in the color memory test was found in the magnetic field 4 +/- 1 microT in comparison with the results in the geomagnetic field. In the magnetic field 0 +/- 1 microT, slight impairment of color memory was found. Preliminary results in the test of reaction rates showed the tendency to slowing down the reaction rates in the weakened magnetic fields.

  12. Magnetic imager and method

    Science.gov (United States)

    Powell, James; Reich, Morris; Danby, Gordon

    1997-07-22

    A magnetic imager 10 includes a generator 18 for practicing a method of applying a background magnetic field over a concealed object, with the object being effective to locally perturb the background field. The imager 10 also includes a sensor 20 for measuring perturbations of the background field to detect the object. In one embodiment, the background field is applied quasi-statically. And, the magnitude or rate of change of the perturbations may be measured for determining location, size, and/or condition of the object.

  13. Structure, electronic and magnetic properties of Ca-doped chromium oxide studied by the DFT method

    International Nuclear Information System (INIS)

    Maldonado, Frank; Rivera, Richard; Stashans, Arvids

    2012-01-01

    Using first-principles density functional theory calculations within the generalised gradient approximation (GGA) as well as GGA+U method we study Ca-doped α-Cr 2 O 3 crystal. Structural, electronic and magnetic properties due to the singular impurity incorporation have been investigated and discussed in detail. Atomic shifts as well as computed Bader charges on atoms imply the importance of ionic nature in the atomic interactions in chromium oxide. The study improves our knowledge on how the crystalline lattice reacts on the presence of a Ca dopant. According to our research it is found that Ca impurity incorporation produces some local changes upon the electronic band structure of the material without occurrence of local states within the band-gap. It is found that Ca incorporation produces change in magnetic behaviour of the crystal: it becomes ferromagnetic.

  14. Structure, electronic and magnetic properties of Ca-doped chromium oxide studied by the DFT method

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado, Frank; Rivera, Richard [Grupo de Fisicoquimica de Materiales, Universidad Tecnica Particular de Loja, Apartado 11-01-608, Loja (Ecuador); Stashans, Arvids, E-mail: arvids@utpl.edu.ec [Grupo de Fisicoquimica de Materiales, Universidad Tecnica Particular de Loja, Apartado 11-01-608, Loja (Ecuador)

    2012-04-15

    Using first-principles density functional theory calculations within the generalised gradient approximation (GGA) as well as GGA+U method we study Ca-doped {alpha}-Cr{sub 2}O{sub 3} crystal. Structural, electronic and magnetic properties due to the singular impurity incorporation have been investigated and discussed in detail. Atomic shifts as well as computed Bader charges on atoms imply the importance of ionic nature in the atomic interactions in chromium oxide. The study improves our knowledge on how the crystalline lattice reacts on the presence of a Ca dopant. According to our research it is found that Ca impurity incorporation produces some local changes upon the electronic band structure of the material without occurrence of local states within the band-gap. It is found that Ca incorporation produces change in magnetic behaviour of the crystal: it becomes ferromagnetic.

  15. A new capacitive/resistive probe method for studying magnetic surfaces

    International Nuclear Information System (INIS)

    Kitajima, Sumio; Takayama, Masakazu; Zama, Tatsuya; Takaya, Kazuhiro; Takeuchi, Nobunao; Watanabe, Hiroshige

    1991-01-01

    A new capacitive/resistive probe method for mapping the magnetic surfaces from resistance or capacitance between a magnetic surface and a vacuum vessel was developed and tested. Those resistances and capacitances can be regarded as components of a simple electrical bridge circuit. This method exploits electrical transient response of the bridge circuit for a square pulse. From equiresistance or equicapacitance points, the magnetic surface structure can be deduced. Measurements on the Tohoku University Heliac, which is a small-size standard heliac, show good agreement with numerical calculations. This method is particularly useful for pulse-operated machines. (author)

  16. Magnetic Properties and Structural Study of Ni-Co/Cu Multilayers Prepared by Electrodeposition Method

    Directory of Open Access Journals (Sweden)

    M. Jafari Fesharaki

    2015-07-01

    Full Text Available Ni-Co/Cu multilayers have been grown by electrodeposition method from a single electrolyte (based on Ni(SO4.6H2O, Co(SO4.7H2O, Cu(SO4 and H3BO3 using galvanostatic control on titanium sublayers. The X-ray diffraction (XRD patterns confirmed the multilayered structure with the nanometer thicknesses. Also, electron diffraction x-ray (EDX  analysis confirmed the purity of deposited samples. The morphology of the samples was estimated by scanning electron microscope (SEM. Magnetoresistance (MR measurements were carried out at room temperature for the Ni-Co/Cu multilayers by measuring the resistivity in a magnetic fields varying between ±6kOe as a function of the Ni-Co and Cu layer thicknesses; (1 dCu(nm 4 and 3 dNi-Cu(nm 5. The Maximum value of giant magnetoresistance (GMR was obtained when the Ni-Co and Cu thicknesses were 4.0nm and 4.0nm respectively. The hysteresis loop of the samples at room temperature was studied using an alternating gradient force magnetometer (AGFM. Finally, the temperature dependence of magnetization for Ni-Co/Cu multilayers; (dNi-Cu(4nm/dCu(2nm and dNi-Cu(3nm/dCu(3nm measured by Faraday balance and decreasing the magnetization with increasing the temperature discussed according to electron scattering due to spin fluctuation.

  17. Structural study in ''ITASY'' volcanic region (centre of Madagascar) by geophysical methods (magnetic and audiomagnetotelluric)

    International Nuclear Information System (INIS)

    Ratsimbazafy, J.B.

    1988-10-01

    The results obtained by magnetic and magnetotelluric methods of survey of ''ITASY'' volcanic region (centre of Madagascar) and their interpretation in correlation with geological data are presented. 27 refs, 18 figs

  18. Magnetic flux concentration methods for magnetic energy harvesting module

    Directory of Open Access Journals (Sweden)

    Wakiwaka Hiroyuki

    2013-01-01

    Full Text Available This paper presents magnetic flux concentration methods for magnetic energy harvesting module. The purpose of this study is to harvest 1 mW energy with a Brooks coil 2 cm in diameter from environmental magnetic field at 60 Hz. Because the harvesting power is proportional to the square of the magnetic flux density, we consider the use of a magnetic flux concentration coil and a magnetic core. The magnetic flux concentration coil consists of an air­core Brooks coil and a resonant capacitor. When a uniform magnetic field crossed the coil, the magnetic flux distribution around the coil was changed. It is found that the magnetic field in an area is concentrated larger than 20 times compared with the uniform magnetic field. Compared with the air­core coil, our designed magnetic core makes the harvested energy ten­fold. According to ICNIRP2010 guideline, the acceptable level of magnetic field is 0.2 mT in the frequency range between 25 Hz and 400 Hz. Without the two magnetic flux concentration methods, the corresponding energy is limited to 1 µW. In contrast, our experimental results successfully demonstrate energy harvesting of 1 mW from a magnetic field of 0.03 mT at 60 Hz.

  19. Mössbauer and magnetic studies of nanocrystalline zinc ferrites synthesized by microwave combustion method

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, Mohamed, E-mail: mamdouh-2000-2000@yahoo.com [Assiut University, Department of Physics (Egypt); Hassan, Azza Mohamed [Asuite University, Physics Department, Faculty of Sciences (Egypt); Ahmed, Mamdouh Abdel aal [Al Azhar University, Physics Department, Faculty of Science (Egypt); Zhu, Kaixin; Ganeshraja, Ayyakannu Sundaram; Wang, Junhu, E-mail: Wangjh@dicp.ac.cn [Chinese Academy Sciences, Mössbauer Effect Data Center & Laboratory of Catalysts and New Materials for Aerospace, Dalian Institute of Chemical Physics (China)

    2016-12-15

    Zinc ferrite nano-crystals were synthesized by a microwave assisted combustion route with varying the urea to metal nitrates (U/N) molar ratio The process takes only a few minutes to obtain Zinc ferrite powders. The Effect of U/N ratio on the obtained phases, particle size, magnetization and structural properties has been investigated. The specimens were characterized by XRD, Mössbauer and VSM techniques. The sample prepared with urea/metal nitrate ratio of 1/1 was a poorly crystalline phase with very small crystallite size. A second phase is also detected in the sample. The crystallite size increases while the second phase decrease with increasing the urea ratio. The saturation magnetization and coercivity of the as prepared nano-particles changed with the change of the U/N ratio. The powder with the highest U/N ratio showed the presence of an unusually high saturation magnetization of 16 emu/g at room temperature. The crystallinity of the as prepared powder was developed by annealing the samples at 700 {sup ∘}C and 900 {sup ∘}C. Both the saturation magnetization (Ms) and the remnant magnetization (Mr) were found to be highly dependent upon the annealing temperature. Mössbauer studies show magnetic ordering in the powder even at room temperature. The Mössbauer and the magnetic parameters of this fraction are different from the standard values for bulk zinc ferrite.

  20. A Noninvasive Method to Study Regulation of Extracellular Fluid Volume in Rats Using Nuclear Magnetic Resonance

    Science.gov (United States)

    Time-domain nuclear magnetic resonance (TD-NMR)-based measurement of body composition of rodents is an effective method to quickly and repeatedly measure proportions of fat, lean, and fluid without anesthesia. TD-NMR provides a measure of free water in a living animal, termed % f...

  1. Study of the magnetic microstructure of high-coercivity sintered SmCo5 permanent magnets with the conventional Bitter pattern technique and the colloid-SEM method

    International Nuclear Information System (INIS)

    Szmaja, Witold

    2007-01-01

    The magnetic microstructure of high-coercivity sintered SmCo 5 permanent magnets was studied with the conventional Bitter pattern technique, and also for the first time with the colloid-scanning electron microscopy (colloid-SEM) method. Both techniques were supported by digital image acquisition, enhancement and analysis. Thanks to this, it was possible to obtain high-contrast and clear images of the magnetic microstructure and to analyze them in detail, and consequently also to achieve improvements over earlier results. In the thermally demagnetized state the grains were composed of magnetic domains. On the surface perpendicular to the alignment axis, the main domains forming a maze pattern and surface reverse spikes were observed. Investigations on the surface parallel to the alignment axis, especially by the colloid-SEM technique, provided a detailed insight into the orientation of grains. The alignment of grains was good, but certainly not perfect; there were also strongly misaligned grains, although generally very rare. In most cases the domain structures within grains were independent of their neighbors, but in some cases (not so rare) the domain walls were observed to continue through the grain boundaries, indicating significant magnetostatic interaction between neighboring grains. Studies of the behavior of the magnetic microstructure under the influence of an external magnetic field, performed for the first time on the surface parallel to the alignment axis (with the conventional Bitter pattern method), showed that the domain walls move easily within the grains and that the magnetization reversal mechanism is mainly related to the nucleation and growth of reverse domains, i.e. that sintered SmCo 5 magnets are nucleation-dominated systems. Groupwise magnetization reversal of adjacent magnetically coupled grains was observed, an unfavorable effect for high-coercivity magnets. Images obtained by the colloid-SEM technique and the conventional Bitter pattern

  2. The importance of magnetic methods for soil mapping and process modelling. Case study in Ukraine

    Science.gov (United States)

    Menshov, Oleksandr; Pereira, Paulo; Kruglov, Oleksandr; Sukhorada, Anatoliy

    2016-04-01

    The correct planning of agriculture areas is fundamental for a sustainable future in Ukraine. After the recent political problems in Ukraine, new challenges emerged regarding sustainability questions. At the same time the soil mapping and modelling are intensively developing all over the world (Pereira et al., 2015; Brevik et al., in press). Magnetic susceptibility (MS) methods are low cost and accurate for the developing maps of agricultural areas, fundamental for Ukrain's economy.This allow to colleact a great amount of soil data, usefull for a better understading of the spatial distribution of soil properties. Recently, this method have been applied in other works in Ukraine and elsewhere (Jordanova et al., 2011; Menshov et al., 2015). The objective of this work is to study the spatial distribution of MS and humus content on the topsoils (0-5 cm) in two different areas. The first is located in Poltava region and the second in Kharkiv region. The results showed that MS depends of soil type, topography and anthropogenic influence. For the interpretation of MS spatial distribution in top soil we consider the frequency and time after the last tillage, tilth depth, fertilizing, and the puddling regarding the vehicle model. On average the soil MS of the top soil of these two cases is about 30-70×10-8 m3/kg. In Poltava region not disturbed soil has on average MS values of 40-50×10-8 m3/kg, for Kharkiv region 50-60×10-8 m3/kg. The tilled soil of Poltava region has on average an MS of 60×10-8 m3/kg, and 70×10-8 m3/kg in Kharkiv region. MS is higher in non-tilled soils than in the tilled ones. The correlation between MS and soil humus content is very high ( up to 0.90) in both cases. Breivik, E., Baumgarten, A., Calzolari, C., Miller, B., Pereira, P., Kabala, C., Jordán, A. Soil mapping, classification, and modelling: history and future directions. Geoderma (in press), doi:10.1016/j.geoderma.2015.05.017 Jordanova D., Jordanova N., Atanasova A., Tsacheva T., Petrov P

  3. Magnetic and photocatalytic studies on Zn1-xMgxFe2O4 nanocolloids synthesized by solvothermal reflux method.

    Science.gov (United States)

    Manohar, A; Krishnamoorthi, C

    2017-12-01

    Biocompatible magnetic semiconductor Zn 1-x Mg x Fe 2 O 4 (x=0, 0.1, 0.3, 0.5 & 0.7) nanoparticles of around 10nm diameter were synthesized by solvothermal reflux method. The method produces well separated and narrow size distributed nanoparticles. Crystal structure, morphology, particles surface properties, surfactant quantity, colloidal stability, magnetic properties and photocatalytic properties of the synthesized nanoparticles were studied. Different characterizations confirmed that all compounds were single crystals and superparamagnetic at room temperature. Saturation mass magnetization (M s =57.5emu/g) enhances with substituent Mg 2+ concentration due to promotion of mixed spinel (normal and inverse) structure. Photocatalytic activity of all synthesized magnetic semiconductor nanoparticles were studied through methylene blue degradation. The degradation of 98% methylene blue was observed on 60 min irradiation of light. It is observed that photocatalytic activity slightly enhances with substituent Mg 2+ concentration. The synthesized biocompatible magnetic semiconductor nanoparticles can be utilized as photocatalysts and could also be recycled and separated by applying an external magnetic field. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Application of magnetic, geochemical and micro-morphological methods in environmental studies of urban pollution generated by road traffic

    Energy Technology Data Exchange (ETDEWEB)

    Bucko, M.

    2012-11-01

    Road traffic is at present one of the major sources of environmental pollution in urban areas. Magnetic particles, heavy metals and other compounds generated by traffic can greatly affect ambient air quality and have direct implications for human health. The general aim of this research was to identify and characterize magnetic vehicle-derived particulates using magnetic, geochemical and micro-morphological methods. A combination of three different methods was used to discriminate sources of particular anthropogenic particles. Special emphasis was placed on the application of various collectors (roadside soil, snow, lichens and moss bags) to monitor spatial and temporal distribution of traffic pollution on roadsides. The spatial distribution of magnetic parameters of road dust accumulated in roadside soil, snow, lichens and moss bags indicates that the highest concentration of magnetic particles is in the sampling points situated closest to the road edge. The concentration of magnetic particles decreases with increasing distance from the road indicating vehicle traffic as a major source of emission. Significant differences in horizontal distribution of magnetic susceptibility were observed between soil and snow. Magnetic particles derived from road traffic deposit on soil within a few meters from the road, but on snow up to 60 m from the road. The values of magnetic susceptibility of road dust deposited near busy urban motorway are significantly higher than in the case of low traffic road. These differences are attributed to traffic volume, which is 30 times higher on motorway than on local road. Moss bags placed at the edge of urban parks situated near major roads show higher values of magnetic susceptibility than moss bags from parks located near minor routes. Enhanced concentrations of heavy metals (e.g. Fe, Mn, Zn, Cu, Cr, Ni and Co) were observed in the studied samples. This may be associated with specific sources of vehicle emissions (e.g. exhaust and non

  5. Superconducting magnet and fabrication method

    Science.gov (United States)

    Israelsson, Ulf E. (Inventor); Strayer, Donald M. (Inventor)

    1994-01-01

    A method of trapping a field in a block of superconductor material, includes providing (i) a block of material defining a bore, (ii) a high permeability core within the bore that defines a low reluctance path through the bore, (iii) a high permeability external structure on the exterior of the block of material that defines a low reluctance path between opposite ends of the core, and (iv) an electromagnet configured to apply a magnetic field around the high permeability core. The method proceeds by energizing the electromagnet to produce an applied magnetic field around the high permeability core, cooling the block of material sufficiently to render the block of material superconducting, de-energizing the electromagnet to result in a trapped magnetic field, and at least partially removing the low reluctance path defined by the core and the external structure in order to increase the magnetic flux density of the trapped magnetic field.

  6. Magnetic studies of cobalt doped barium hexaferrite nanoparticles prepared by modified sol-gel method

    International Nuclear Information System (INIS)

    Shalini, M. Govindaraj; Sahoo, Subasa C.

    2016-01-01

    M-type barium hexaferrite (BaFe_1_2O_1_9) and cobalt doped barium hexaferrite (BaFe_1_1CoO_1_9) nanopowders were synthesized by modified sol-gel auto-combustion technique and were annealed at 900°C in air for 4 hours. The annealed powders were studied in the present work and X-ray diffraction studies showed pure phase formation after annealing. The average grain size in the nanopowder sample was decreased after doping. Magnetization value of 60 emu/g was observed at 300 K for the barium hexaferrite and was reduced to 54 emu/g after doping. The coercivity of 5586 Oe was observed at 300 K for the undoped sample and was found to be decreased in the doped sample. As the measurement temperature was decreased from 300 K to 60 K, magnetization value was increased in both the samples compared to those at 300 K. The coercivity of the undoped sample was found to decrease whereas it was increased for the doped sample at 60 K. The observed magnetic properties may be understood on the basis of modified exchange interaction and anisotropy in the doped sample compared to that of pure barium hexaferrite.

  7. Relativistic effects on magnetic circular dichroism studied by GUHF/SECI method

    Science.gov (United States)

    Honda, Y.; Hada, M.; Ehara, M.; Nakatsuji, H.; Downing, J.; Michl, J.

    2002-04-01

    Quasi-relativistic formulation of the Magnetic circular dichroism (MCD) Faraday terms are presented using the generalized unrestricted Hartree-Fock (GUHF)/single excitation configuration interaction (SECI) method combined with the finite perturbation method and applied to the MCD of the three n-σ ∗ states ( 3Q1, 3Q0, 1Q1) of CH 3I. The Faraday B term for the 1Q1 state was 0.1976( Debye) 2( Bohr magneton )/(10 3 cm-1) in the non-relativistic theory, but was dramatically improved by the relativistic effect and became 0.0184 in agreement with the experimental values, 0.014 and 0.0257. This change was mainly due to the one-electron spin-orbit (SO1) term rather than the spin-free relativistic (SFR) and the two-electron spin-orbit (SO2) terms.

  8. Estimation of Soil Erosion by Using Magnetic Method: A Case Study of an Agricultural Field in Southern Moravia (Czech Republic)

    Science.gov (United States)

    Petrovsky, E.; Grison, H.; Kapicka, A.; Dlouha, S.; Kodesova, R.; Jaksik, O.

    2013-05-01

    In this study we have applied magnetism of soils for estimation of erosion at an agricultural land. The testing site is situated in loess region in Southern Moravia (in Central Europe). The approach is based on well-established method of differentiation of magnetic parameters of the topsoil and the subsoil horizons as a result of in situ formation of strongly magnetic iron oxides. Our founding is established on a simple tillage homogenization model described by Royall (2001) using magnetic susceptibility and its frequency dependence to estimate soil loss caused by the tillage and subsequent erosion. The original dominant Soil Unit in the investigated area is Haplic Chernozem, which is due to intensive erosion progressively transformed into different Soil Units. The site is characterized by a flat upper part while the middle part, formed by a substantive side valley, is steeper (up to 15°). The side valley represents a major line of concentrated runoff emptying into a colluvial fan. Field measurements of the topsoil volume magnetic susceptibility were carried out by the Bartington MS2D probe. Data are resulting in regular grid of 101 data points, where the bulk soil material was gathered for further laboratory investigations. Moreover, vertical distribution of magnetic susceptibility (deep to 40 cm) was measured on selected transects using the SM400 kappameter. In the laboratory, after drying and sieving of collected soil samples, mass-specific magnetic susceptibility and its frequency-dependent susceptibility was measured. In order to identify magnetic minerals the thermomagnetic analyses were performed using the AGICO KLY-4S Kappabridge with CS-3 furnace. Hysteresis loops were carried out on vibrating magnetometer ADE EV9 to assess the grain-size distribution of ferrimagnetic particles. Hereafter, the isothermal remanent magnetization acqusition followed by D.C. demagnetization were done. All these laboratory magnetic measurements were performed in order to

  9. Optimization of Archeological Anomalies using GIS method for Magnetic and Resistivity Study at Sungai Batu, Lembah Bujang, Kedah (Malaysia)

    Science.gov (United States)

    Yusoh, R.; Saad, R.; Saidin, M.; Anda, S. T.; Muhammad, S. B.; Ashraf, M. I. M.; Hazreek, Z. A. M.

    2018-04-01

    Magnetic and resistivity method has become a reliable option in archeological exploration. The use of both method has become popular these day. However, both method gives different type of sensing in detecting anomalies and direct interpret from the anomalies will result large coverage area for excavation. Therefore, to overcome this issue, both anomalies can be extracted using ArcGIS software to reduce excavated coverage area. The case study located at Sungai Batu, Lembah Bujang near SB2ZZ lot expected buried clay brick monument which will be a perfect case to apply this technique. Magnetic and resistivity method was implemented at the study area where the anomalies coverage area for magnetic and resistivity is 531.5 m2 and 636 m2 respectively which total area of both anomalies was 764 m2. By applying combine technique, the anomalies area reduce to 403.7 m2 which reduce the suspected anomalies by 47.16 %. The unsuspected clay brick monument area was increase from 15.86% to 55.54% which improve the cost and labor work for excavation.

  10. Neutron Scattering studies of magnetic molecular magnets

    International Nuclear Information System (INIS)

    Chaboussant, G.

    2009-01-01

    This work deals with inelastic neutron scattering studies of magnetic molecular magnets and focuses on their magnetic properties at low temperature and low energies. Several molecular magnets (Mn 12 , V 15 , Ni 12 , Mn 4 , etc.) are reviewed. Inelastic neutron scattering is shown to be a perfectly suited spectroscopy tool to -a) probe magnetic energy levels in such systems and -b) provide key information to understand the quantum tunnel effect of the magnetization in molecular spin clusters. (author)

  11. Investigation of polluted alluvial soils by magnetic susceptibility methods: a case study of the Litavka River

    Czech Academy of Sciences Publication Activity Database

    Dlouhá, Šárka; Petrovský, Eduard; Kapička, Aleš; Borůvka, L.; Ash, Ch.; Drábek, O.

    2013-01-01

    Roč. 8, č. 4 (2013), s. 151-157 ISSN 1801-5395 Institutional support: RVO:67985530 Keywords : environmental magnetism * Fluvisols * magnetite/maghemite * risk elements Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.615, year: 2013

  12. A systematic first principle method to study magnetic properties of FeMo, CoMo and NiMo

    International Nuclear Information System (INIS)

    Bhattacharjee, Ashis Kumar; Touheed, Md.; Ahmed, Mesbahuddin; Halder, A.; Mookerjee, A.

    2003-06-01

    We use the first principle TB-LMTO (Tight-Binding Linear Muffin Tin Orbital) method combined with the ASM (Augmented Space Method) to take care of disorder beyond the mean field (CPA - Cohetent Potential Approximation) approximation. We analyze binary alloys between magnetic transition metals Fe, Co, Ni and non-magnetic Mo to find out the effect of disorder on electronic structure and consequently magnetic properties of the alloys. (author)

  13. The Grad-Shafranov Reconstruction of Toroidal Magnetic Flux Ropes: Method Development and Benchmark Studies

    Science.gov (United States)

    Hu, Qiang

    2017-09-01

    We develop an approach of the Grad-Shafranov (GS) reconstruction for toroidal structures in space plasmas, based on in situ spacecraft measurements. The underlying theory is the GS equation that describes two-dimensional magnetohydrostatic equilibrium, as widely applied in fusion plasmas. The geometry is such that the arbitrary cross-section of the torus has rotational symmetry about the rotation axis, Z, with a major radius, r0. The magnetic field configuration is thus determined by a scalar flux function, Ψ, and a functional F that is a single-variable function of Ψ. The algorithm is implemented through a two-step approach: i) a trial-and-error process by minimizing the residue of the functional F(Ψ) to determine an optimal Z-axis orientation, and ii) for the chosen Z, a χ2 minimization process resulting in a range of r0. Benchmark studies of known analytic solutions to the toroidal GS equation with noise additions are presented to illustrate the two-step procedure and to demonstrate the performance of the numerical GS solver, separately. For the cases presented, the errors in Z and r0 are 9° and 22%, respectively, and the relative percent error in the numerical GS solutions is smaller than 10%. We also make public the computer codes for these implementations and benchmark studies.

  14. Experimental study of fly-ash migration by using magnetic method

    Czech Academy of Sciences Publication Activity Database

    Kapička, Aleš; Kodešová, R.; Petrovský, Eduard; Hůlka, Z.; Grison, Hana; Kaška, M.

    2011-01-01

    Roč. 55, č. 4 (2011), s. 683-696 ISSN 0039-3169 R&D Projects: GA AV ČR IAA300120701 Grant - others:GA AV ČR(CZ) M100120901 Institutional research plan: CEZ:AV0Z30120515 Keywords : environmental magnetism * fly-ash migration * magnetic susceptibility * SM400 Kappameter Subject RIV: DK - Soil Contamination ; De-contamination incl. Pesticides Impact factor: 0.700, year: 2011

  15. Modified small angle magnetization rotation method in multilayer magnetic microwires

    International Nuclear Information System (INIS)

    Torrejon, J.; Badini, G.; Pirota, K.; Vazquez, M.

    2007-01-01

    The small angle magnetization rotation (SAMR) technique is a widely used method to quantify magnetostriction in elongated ultrasoft magnetic materials. In the present work, we introduce significant optimization of the method, particularly simplification of the required equipment, profiting of the very peculiar characteristics of a recently introduced family of multilayer magnetic microwires consisting of a soft magnetic core, insulating intermediate layer and a hard magnetic outer layer. The introduced modified SAMR method is used not only to determine the saturation magnetostriction constant of the soft magnetic nucleus but also the magnetoelastic and magnetostatic coupling. This new method has a great potential in multifunctional sensor applications

  16. Study on magnetic property and fracture behavior of magnetic materials

    International Nuclear Information System (INIS)

    Miya, Kenzo; Demachi, Kazuyuki; Aoto, Kazumi; Nagae, Yuji

    2002-04-01

    Establishment of evaluation methods of material degradation before crack initiation is needed very much to enhance the reliability of structural components. We remark magnetic methods in this report. Our objectives are to reveal the relation between degradation and magnetic property and to develop evaluation methods of material degradation, especially plastic deformation and stress corrosion cracking (SCC). In the former part of this report, evaluation methods for plastic deformation are discussed. At first, the study that shows the relation between the magnetic flux leakage and plastic deformation is reviewed. We developed the inverse analysis method of magnetization to specify the degradation distribution. Moreover, we propose inverse analysis of magnetic susceptibility for quantitative evaluation. In the latter part, the topic is SCC. We measured the magnetic flux leakage from the sample induced a SCC crack (Inconel 600). Inconel 600 is a paramagnetic material at room temperature but the sample shows ferromagnetic and the magnetic flux leakage was changed near the SCC crack. The possibility of detection of a SCC crack is shown by the inverse analysis result from the magnetic flux leakage. Finally, it is recognized by observation of the micro magnetic distributions by using a magnetic force microscope that the magnetization has relation with chromium depletion near grain boundaries and it is weak near the SCC crack. From these results, the magnetic method is very effective for evaluation of degradation. (author)

  17. A Preliminary Study on the Synthesis and Characterization of Multilayered Ag/Co Magnetic Nanowires Fabricated via the Electrodeposition Method

    Directory of Open Access Journals (Sweden)

    Cheng-Hsiung Peng

    2013-01-01

    Full Text Available A single-bath electrodeposition method was developed to integrate multilayer Ag/Co nanowires with a commercial anodic alumina oxide (AAO template with a pore diameter of 100–200 nm. An electrolyte system containing silver nitride and cobalt sulfide was studied using cyclic voltammetry, and the electrodeposition rate was varied to optimize the electrodeposition conditions. A constant stepwise potential and a variable cation ratio of [Co2+]/[Ag+] were used during electrodeposition. After the dissolution of the template in aqueous NaOH solution, multilayered Ag/Co nanowires were obtained with a composition of [Co]/[Ag80Co20], as identified by XRD and TEM, when [Co2+]/[Ag+] = 150. By annealing at 200°C for 1 h, uniformly structured (Co99.57/Ag100 nanowires were obtained. Compared with pure Co nanowires, the magnetic hysteresis loops showed a greater magnetic anisotropy for (Co99.57/Ag100 nanowires than for pure Co nanowires, corresponding to a change in the easy axis upon magnetization.

  18. Magnetic study of turbidites

    Science.gov (United States)

    Tanty, Cyrielle; Valet, Jean Pierre; Carlut, Julie

    2015-04-01

    Turbidites induce sedimentary reworking and re-deposition caused by tsunami, earthquake, volcanic processes, and other catastrophic events. They result from rapid depositional processes and are thus considered not being pertinent for comparison with pelagic sediments. Turbidites are evidently ruled out from paleomagnetic records dealing with time-series. Consequently, no attention has ever been paid to the magnetization of turbidites which is fully justified if the high level of turbulence governing the depositional processes influences the acquisition of magnetization. In certain conditions like channeled turbidity currents, levees of sediment are generated and then associated with relatively calm although very fast redeposition processes. Such conditions will thus govern the subsequent acquisition of magnetization through mechanical lock-in of the magnetic grains. This situation is actually quite similar to what happens during the experiences of artificial redeposition that are conducted in laboratory. Therefore, combining laboratory experiments and studies of natural turbidites could reveal important information on the processes involved in the acquisition of magnetization, especially if the comparison with the overlying hemipelagic sediments does not show any striking difference. We will present the results of magnetic measurements performed on four different and relatively recent turbidites. We selected different origins associated either with spillover of channeled turbidity currents or with co-seismic faulting. Each event is characterized by a different thickness (ten to few tens of cm), lithology and mean granulometry (few tens of μm to hundreds of μm). We have carried out measurements of magnetic susceptibility, magnetic remanence, anisotropy of magnetic susceptibility (AMS) and we also scrutinize the evolution of various rock magnetic parameters (ARM, IRM, S ratio, magnetic grain sizes, hysteresis parameters…). The magnetic characteristics of the

  19. Nuclear magnetic resonance imaging method

    International Nuclear Information System (INIS)

    Johnson, G.; MacDonald, J.; Hutchison, S.; Eastwood, L.M.; Redpath, T.W.T.; Mallard, J.R.

    1984-01-01

    A method of deriving three dimensional image information from an object using nuclear magnetic resonance signals comprises subjecting the object to a continuous, static magnetic field and carrying out the following set of sequential steps: 1) exciting nuclear spins in a selected volume (90deg pulse); 2) applying non-aligned first, second and third gradients of the magnetic field; 3) causing the spins to rephase periodically by reversal of the first gradient to produce spin echoes, and applying pulses of the second gradient prior to every read-out of an echo signal from the object, to differently encode the spin in the second gradient direction for each read-out signal. The above steps 1-3 are then successively repeated with different values of gradient of the third gradient, there being a recovery interval between the repetition of successive sets of steps. Alternate echoes only are read out, the other echoes being time-reversed and ignored for convenience. The resulting signals are appropriately sampled, set out in an array and subjected to three dimensional Fourier transformation. (author)

  20. 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)

  1. Magnetic refrigeration apparatus and method

    Science.gov (United States)

    Barclay, John A.; Overton, Jr., William C.; Stewart, Walter F.

    1984-01-01

    The disclosure relates to refrigeration through magnetizing and demagnitizing a body by rotating it within a magnetic field. Internal and external heat exchange fluids and in one embodiment, a regenerator, are used.

  2. Method of regulating magnetic field of magnetic pole center

    International Nuclear Information System (INIS)

    Watanabe, Masao; Yamada, Teruo; Kato, Norihiko; Toda, Yojiro; Kaneda, Yasumasa.

    1978-01-01

    Purpose: To provide the subject method comprising using a plurality of magnetic metal pieces having different thicknesses, regulating very easily symmetry of the field of the magnetic pole center depending upon the combination of said metal pieces, thereby obtaining a magnetic field of high precision. Method: The regulation of magnetic field at the central part of the magnetic field is not depending only upon processing of the center plug, axial movement of trim coil and ion source but by providing a magnetic metal piece such as an iron ring, primary higher harmonics of the field at the center of the magnetic field can be regulated simply while the position of the ion source slit is on the equipotential surface in the field. (Yoshihara, H.)

  3. 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)

  4. Study of the method of water-injected meat identifying based on low-field nuclear magnetic resonance

    Science.gov (United States)

    Xu, Jianmei; Lin, Qing; Yang, Fang; Zheng, Zheng; Ai, Zhujun

    2018-01-01

    The aim of this study to apply low-field nuclear magnetic resonance technique was to study regular variation of the transverse relaxation spectral parameters of water-injected meat with the proportion of water injection. Based on this, the method of one-way ANOVA and discriminant analysis was used to analyse the differences between these parameters in the capacity of distinguishing water-injected proportion, and established a model for identifying water-injected meat. The results show that, except for T 21b, T 22e and T 23b, the other parameters of the T 2 relaxation spectrum changed regularly with the change of water-injected proportion. The ability of different parameters to distinguish water-injected proportion was different. Based on S, P 22 and T 23m as the prediction variable, the Fisher model and the Bayes model were established by discriminant analysis method, qualitative and quantitative classification of water-injected meat can be realized. The rate of correct discrimination of distinguished validation and cross validation were 88%, the model was stable.

  5. Orbital studies of lunar magnetism

    Science.gov (United States)

    Mcleod, M. G.; Coleman, P. J., Jr.

    1982-01-01

    Limitations of present lunar magnetic maps are considered. Optimal processing of satellite derived magnetic anomaly data is also considered. Studies of coastal and core geomagnetism are discussed. Lunar remanent and induced lunar magnetization are included.

  6. Temperature dependent and applied field strength dependent magnetic study of cobalt nickel ferrite nano particles: Synthesized by an environmentally benign method

    Science.gov (United States)

    Sontu, Uday Bhasker; G, Narsinga Rao; Chou, F. C.; M, V. Ramana Reddy

    2018-04-01

    Spinel ferrites have come a long way in their versatile applications. The ever growing applications of these materials demand detailed study of material properties and environmental considerations in their synthesis. In this article, we report the effect of temperature and applied magnetic field strength on the magnetic behavior of the cobalt nickel ferrite nano powder samples. Basic structural properties of spinel ferrite nano particles, that are synthesized by an environmentally benign method of auto combustion, are characterized through XRD, TEM, RAMAN spectroscopy. Diffuse Reflectance Spectroscopy (DRS) is done to understand the nickel substitution effect on the optical properties of cobalt ferrite nano particles. Thermo magnetic studies using SQUID in the temperature range 5 K to 400 K and room temperature (300 K) VSM studies are performed on these samples. Fields of 0Oe (no applied field: ZF), 1 kOe (for ZFC and FC curves), 5 kOe (0.5 T), 50 kOe (5T) (for M-H loop study) are used to study the magnetic behavior of these nano particles. The XRD,TEM analysis suggest 40 nm crystallites that show changes in the cation distribution and phase changes in the spinel structure with nickel substitution. Raman micrographs support phase purity changes and cation redistributions with nickel substitution. Diffuse reflectance study on powder samples suggests two band gap values for nickel rich compounds. The Magnetic study of these sample nano particles show varied magnetic properties from that of hard magnetic, positive multi axial anisotropy and single-magnetic-domain structures at 5 K temperature to soft magnetic core shell like structures at 300 K temperature. Nickel substitution effect is non monotonous. Blocking temperature of all the samples is found to be higher than the values suggested in the literature.

  7. 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.

  8. Superconducting magnetic shielding apparatus and method

    Science.gov (United States)

    Clem, John R.; Clem, John R.

    1983-01-01

    Disclosed is a method and apparatus for providing magnetic shielding around a working volume. The apparatus includes a hollow elongated superconducting shell or cylinder having an elongated low magnetic pinning central portion, and two high magnetic pinning end regions. Transition portions of varying magnetic pinning properties are interposed between the central and end portions. The apparatus further includes a solenoid substantially coextensive with and overlying the superconducting cylinder, so as to be magnetically coupled therewith. The method includes the steps passing a longitudinally directed current through the superconducting cylinder so as to depin magnetic reservoirs trapped in the cylinder. Next, a circumferentially directed current is passed through the cylinder, while a longitudinally directed current is maintained. Depinned magnetic reservoirs are moved to the end portions of the cylinder, where they are trapped.

  9. Superconducting magnetic shielding apparatus and method

    Science.gov (United States)

    Clem, J.R.

    1982-07-09

    Disclosed is a method and apparatus for providing magnetic shielding around a working volume. The apparatus includes a hollow elongated superconducting shell or cylinder having an elongated low magnetic pinning central portion, and two high magnetic pinning end regions. Transition portions of varying magnetic pinning properties are interposed between the central and end portions. The apparatus further includes a solenoid substantially coextensive with and overlying the superconducting cylinder, so as to be magnetically coupled therewith. The method includes the steps passing a longitudinally directed current through the superconducting cylinder so as to depin magnetic reservoirs trapped in the cylinder. Next, a circumferentially directed current is passed through the cylinder, while a longitudinally directed current is maintained. Depinned magnetic reservoirs are moved to the end portions of the cylinder, where they are trapped.

  10. Separation of magnetic from non-magnetic information in the Bitter pattern method

    International Nuclear Information System (INIS)

    Szmaja, Witold

    2001-01-01

    The paper deals with the problem of separating magnetic and non-magnetic contributions to the image contrast in the Bitter pattern method. With the help of the digital image difference procedure, it is demonstrated for the first time for the Bitter method that the separation is easy to achieve for relatively soft magnetic specimens, when an external field can be applied to simply produce the non-magnetic reference image of the specimen area under study. It is also shown that obtaining satisfactory results is principally impossible when removing the colloid from the specimen surface is used for the purpose of recording the non-magnetic image

  11. A comparative study of magnetic properties of MnFe2O4 nanoparticles prepared by thermal decomposition and solvothermal methods

    Directory of Open Access Journals (Sweden)

    B Aslibeiki

    2017-09-01

    Full Text Available A comparative study of magnetic properties of MnFe2O4 ferrite nanoparticles prepared by two different methods has been reported. The first sample (S1 was synthesized by thermal decomposition of metal nitrates. And the second sample (S2 was prepared by solvothermal method using Tri-ethylene glycol (TEG. Magnetic hysteresis loops at 300 and 5 K; magnetization and AC susceptibility measurements versus temperature confirmed the effective role of TEG on the magnetic properties of nanoparticles. The results showed that, at 300 K the saturation magnetization (MS of S2 sample is 46% greater than that of S1 sample. At 5 K, the difference in MS of the samples raised to 60%. AC susceptibility measurements at different frequencies and also magnetization versus temperature under field cooling and zero field cooling processes revealed that, the TEG molecules influence the surface spins order of S2 sample. The sample S1 showed strongly interacting superspin glass state, while the sample S2 consists of weakly interacting superparamagnetic nanoparticles.

  12. Study of magnetization switching in coupled magnetic nanostructured systems

    Science.gov (United States)

    Radu, Cosmin

    A study of magnetization dynamics experiments in nanostructured materials using the rf susceptibility tunnel diode oscillator (TDO) method is presented along with a extensive theoretical analysis. An original, computer controlled experimental setup that measures the change in susceptibility with the variation in external magnetic field and sample temperature was constructed. The TDO-based experiment design and construction is explained in detail, showing all the elements of originality. This experimental technique has proven reliable for characterizing samples with uncoupled magnetic structure and various magnetic anisotropies like: CrO2, FeCo/IrMn and Co/SiO2 thin films. The TDO was subsequently used to explore the magnetization switching in coupled magnetic systems, like synthetic antiferromagnet (SAF) structures. Magnetoresistive random access memory (MRAM) is an important example of devices where the use of SAF structure is essential. To support the understanding of the SAF magnetic behavior, its configuration and application are reviewed and more details are provided in an appendix. Current problems in increasing the scalability and decreasing the error rate of MRAM devices are closely connected to the switching properties of the SAF structures. Several theoretical studies that were devoted to the understanding of the concepts of SAF critical curve are reviewed. As one can notice, there was no experimental determination of SAF critical curve, due to the difficulties in characterizing a magnetic coupled structure. Depending of the coupling strength between the two ferromagnetic layers, on the SAF critical curve one distinguishes several new features, inexistent in the case of uncoupled systems. Knowing the configuration of the SAF critical curve is of great importance in order to control its switching characteristics. For the first time a method of experimentally recording the critical curve for SAF is proposed in this work. In order to overcome technological

  13. Magnetic resonance spectroscopy as an imaging method

    International Nuclear Information System (INIS)

    Bomsdorf, H.; Imme, M.; Jensen, D.; Kunz, D.; Menhardt, W.; Ottenberg, K.; Roeschmann, P.; Schmidt, K.H.; Tschendel, O.; Wieland, J.

    1990-01-01

    An experimental Magnetic Resonance (MR) system with 4 tesla flux density was set up. For that purpose a data acquisition system and RF coils for resonance frequencies up to 170 MHz were developed. Methods for image guided spectroscopy as well as spectroscopic imaging focussing on the nuclei 1 H and 13 C were developed and tested on volunteers and selected patients. The advantages of the high field strength with respect to spectroscopic studies were demonstrated. Developments of a new fast imaging technique for the acquisition of scout images as well as a method for mapping and displaying the magnetic field inhomogeneity in-vivo represent contributions to the optimisation of the experimental procedure in spectroscopic studies. Investigations on the interaction of RF radiation with the exposed tissue allowed conclusions regarding the applicability of MR methods at high field strengths. Methods for display and processing of multi-dimensional spectroscopic imaging data sets were developed and existing methods for real-time image synthesis were extended. Results achieved in the field of computer aided analysis of MR images comprised new techniques for image background detection, contour detection and automatic image interpretation as well as knowledge bases for textural representation of medical knowledge for diagnosis. (orig.) With 82 refs., 3 tabs., 75 figs [de

  14. Magnetic resonance in zero-field: construction of a spectrometer, evaluation of a method for structure studies

    International Nuclear Information System (INIS)

    Llor, M.

    1987-01-01

    The method known as Nuclear Resonance in the zero-field, applied to the spectral analysis of powders, is discussed. In the method, the anisotropy due to the preferential direction of the magnetic field is suppressed, but a high sensitivity is keeped. For powders spectra, the process allows the obtention resolutions, of dipolar and quadrupolar couplings, in the range of those only obtained on monocrystals under strong fields. By suitable magnetic field oscillations, and by the effect of the high field on the RMN signal, the transient evolutions of the spins are obtained. Concerning the absence of a preferred direction in the zero-field, a powder or the monocrystals show nearly the same behavior. In such conditions, a much more interesting spectra than those from a powder in a strong field, can be obtained. The RMN spectrometer is described. The possibilities, the experimental and theoretical limits of the proposed method, are analyzed. Applications on dipolar (proton and phosphor) and quadrupolar (deuterium) interactions, on hydrated salts and on cyclophasphazenes are carried out [fr

  15. Novel magnetic controlled plasma sputtering method

    International Nuclear Information System (INIS)

    Axelevich, A.; Rabinovich, E.; Golan, G.

    1996-01-01

    A novel method to improve thin film vacuum sputtering is presented. This method is capable of controlling the sputtering plasma via an external set of magnets, in a similar fashion to the tetrode sputtering method. The main advantage of the Magnetic Controlled Plasma Sputtering (MCPS) is its ability to independently control all deposition parameters without any interference or cross-talk. Deposition rate, using the MCPS, is found to be almost twice the rate of triode and tetrode sputtering techniques. Experimental results using the MCPS to deposit Ni layers are described. It was demonstrated that using the MCPS method the ion beam intensity at the target is a result of the interaction of a homogeneous external magnetic field and the controlling magnetic fields. The MCPS method was therefore found to be beneficial for the production of pure stoichiometric thin solid films with high reproducibility. This method could be used for the production of compound thin films as well. (authors)

  16. Magnetic method for stimulating transport in fluids

    Science.gov (United States)

    Martin, James E.; Solis, Kyle J.

    2016-10-18

    A method for producing mass and heat transport in fluids, wherein the method does not rely on conventional convection, that is, it does not require gravity, a thermal gradient, or a magnetic field gradient. This method gives rise to a unique class of vigorous, field-controllable flow patterns termed advection lattices. The advection lattices can be used to transport heat and/or mass in any desired direction using only magnetic fields.

  17. Method for reducing snap in magnetic amplifiers

    Science.gov (United States)

    Fischer, R. L. E.; Word, J. L.

    1968-01-01

    Method of reducing snap in magnetic amplifiers uses a degenerative feedback circuit consisting of a resistor and a separate winding on a magnetic core. The feedback circuit extends amplifier range by allowing it to be used at lower values of output current.

  18. New magnetic resonance imaging methods in nephrology

    Science.gov (United States)

    Zhang, Jeff L.; Morrell, Glen; Rusinek, Henry; Sigmund, Eric; Chandarana, Hersh; Lerman, Lilach O.; Prasad, Pottumarthi Vara; Niles, David; Artz, Nathan; Fain, Sean; Vivier, Pierre H.; Cheung, Alfred K.; Lee, Vivian S.

    2013-01-01

    Established as a method to study anatomic changes, such as renal tumors or atherosclerotic vascular disease, magnetic resonance imaging (MRI) to interrogate renal function has only recently begun to come of age. In this review, we briefly introduce some of the most important MRI techniques for renal functional imaging, and then review current findings on their use for diagnosis and monitoring of major kidney diseases. Specific applications include renovascular disease, diabetic nephropathy, renal transplants, renal masses, acute kidney injury and pediatric anomalies. With this review, we hope to encourage more collaboration between nephrologists and radiologists to accelerate the development and application of modern MRI tools in nephrology clinics. PMID:24067433

  19. Magnetic flux reconstruction methods for shaped tokamaks

    International Nuclear Information System (INIS)

    Tsui, Chi-Wa.

    1993-12-01

    The use of a variational method permits the Grad-Shafranov (GS) equation to be solved by reducing the problem of solving the 2D non-linear partial differential equation to the problem of minimizing a function of several variables. This high speed algorithm approximately solves the GS equation given a parameterization of the plasma boundary and the current profile (p' and FF' functions). The author treats the current profile parameters as unknowns. The goal is to reconstruct the internal magnetic flux surfaces of a tokamak plasma and the toroidal current density profile from the external magnetic measurements. This is a classic problem of inverse equilibrium determination. The current profile parameters can be evaluated by several different matching procedures. Matching of magnetic flux and field at the probe locations using the Biot-Savart law and magnetic Green's function provides a robust method of magnetic reconstruction. The matching of poloidal magnetic field on the plasma surface provides a unique method of identifying the plasma current profile. However, the power of this method is greatly compromised by the experimental errors of the magnetic signals. The Casing Principle provides a very fast way to evaluate the plasma contribution to the magnetic signals. It has the potential of being a fast matching method. The performance of this method is hindered by the accuracy of the poloidal magnetic field computed from the equilibrium solver. A flux reconstruction package has been implemented which integrates a vacuum field solver using a filament model for the plasma, a multi-layer perception neural network as an interface, and the volume integration of plasma current density using Green's functions as a matching method for the current profile parameters. The flux reconstruction package is applied to compare with the ASEQ and EFIT data. The results are promising

  20. Investigation of Unbalanced Magnetic Force in Magnetic Geared Machine Using Analytical Methods

    DEFF Research Database (Denmark)

    Zhang, Xiaoxu; Liu, Xiao; Chen, Zhe

    2016-01-01

    The electromagnetic structure of the magnetic geared machine (MGM) may induce a significant unbalanced magnetic force (UMF). However, few methods have been developed to theoretically reveal the essential reasons for this issue in the MGM. In this paper, an analytical method based on an air....... Second, the magnetic field distribution in the MGM is modeled by an exact subdomain method, which allows the magnetic forces to be calculated quantitatively. The magnetic forces in two MGMs are then studied under no-load and full-load conditions. Finally, the finite-element calculation confirms......-gap relative permeance theory is first developed to qualitatively study the origins of the UMF in the MGM. By means of formula derivations, three kinds of magnetic field behaviors in the air gaps are found to be the potential sources of UMF. It is also proved that the UMF is possible to avoid by design choices...

  1. Nuclear magnetic resonance method and apparatus

    International Nuclear Information System (INIS)

    Burl, M.; Young, I.R.

    1984-01-01

    A method and apparatus for determining the rate of flow of a liquid in a selected region of a body by nuclear magnetic resonance techniques are described. The method includes a sequence of applying a first magnetic pulse effective to excite nuclear magnetic resonance of a chosen nucleus within the liquid preferentially in a slice of the body which includes the selected region. A period of time (tsub(D)) is waited and then a second magnetic pulse is applied which is effective to excite nuclear magnetic resonance of the nuclei preferentially in the slice, and the free induction decay signal is measured. The whole sequence is repeated for different values of the period of time (tsub(D)). The variation in the value of the measured signal with tsub(D) is then related to the rate of flow of the liquid through the slice. (author)

  2. Magnetic Helicity Estimations in Models and Observations of the Solar Magnetic Field. III. Twist Number Method

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Y. [School of Astronomy and Space Science and Key Laboratory of Modern Astronomy and Astrophysics in Ministry of Education, Nanjing University, Nanjing 210023 (China); Pariat, E.; Moraitis, K. [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, F-92190 Meudon (France); Valori, G. [University College London, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey, RH5 6NT (United Kingdom); Anfinogentov, S. [Institute of Solar-Terrestrial Physics SB RAS 664033, Irkutsk, P.O. box 291, Lermontov Street, 126a (Russian Federation); Chen, F. [Max-Plank-Institut für Sonnensystemforschung, D-37077 Göttingen (Germany); Georgoulis, M. K. [Research Center for Astronomy and Applied Mathematics of the Academy of Athens, 4 Soranou Efesiou Street, 11527 Athens (Greece); Liu, Y. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Thalmann, J. K. [Institute of Physics, Univeristy of Graz, Universitätsplatz 5/II, A-8010 Graz (Austria); Yang, S., E-mail: guoyang@nju.edu.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2017-05-01

    We study the writhe, twist, and magnetic helicity of different magnetic flux ropes, based on models of the solar coronal magnetic field structure. These include an analytical force-free Titov–Démoulin equilibrium solution, non-force-free magnetohydrodynamic simulations, and nonlinear force-free magnetic field models. The geometrical boundary of the magnetic flux rope is determined by the quasi-separatrix layer and the bottom surface, and the axis curve of the flux rope is determined by its overall orientation. The twist is computed by the Berger–Prior formula, which is suitable for arbitrary geometry and both force-free and non-force-free models. The magnetic helicity is estimated by the twist multiplied by the square of the axial magnetic flux. We compare the obtained values with those derived by a finite volume helicity estimation method. We find that the magnetic helicity obtained with the twist method agrees with the helicity carried by the purely current-carrying part of the field within uncertainties for most test cases. It is also found that the current-carrying part of the model field is relatively significant at the very location of the magnetic flux rope. This qualitatively explains the agreement between the magnetic helicity computed by the twist method and the helicity contributed purely by the current-carrying magnetic field.

  3. Preconcentration of low grade uranium ores by gravity and magnetic methods: a case study with copper tailings from Singhbhum, Bihar, India

    International Nuclear Information System (INIS)

    Natarajan, R.; Sreenivas, T.; Krishna Rao, N.

    1992-01-01

    The physical beneficiation methods applied to uranium ores are gravity and magnetic techniques. Feasibility of application of these two techniques has been industrially demonstrated in the case of Palabora copper-uranium ores and Witwatersrand gold-uranium ores respectively. In India exhaustive studies have been carried out on the application of gravity and magnetic methods for preconcentration of uranium values from tailings of copper plants at Surda, Rakha and Mosabani in Singhbhum. While recovery by shaking tables is poor owing to non-liberation and inefficient recovery in finer particle sizes (-37μm), gravity machines like Bartles Mozely Separator and Bartles Cross Belt Concentrator are able to give improved recovery in sizes down to about 15μm. Application of Wet High Intensity Magnetic Separator (WHIMS) is able to improve the recovery to about 75 to 85% from the three tailings, and the improvement is due to the ability of WHIMS collect the micaceous mineral particles containing composite uranium values, as well as uraninite particles down to about 10μm in size. WHIMS is inefficient in recovering uraninite particles below 5μm. High Gradient Magnetic Separator and Super Conducting High Gradient Magnetic Separator, on the other hand, are able to give enhanced recovery of even < 5μm uraninite particles. With the improved technology of gravity and magnetic methods now available, it should now be techno-economically feasible to employ preconcentration of low tenor uranium ores by physical beneficiation, prior to chemical processing. (author). 25 refs. 8 figs, 5 tabs

  4. Historic Methods for Capturing Magnetic Field Images

    Science.gov (United States)

    Kwan, Alistair

    2016-01-01

    I investigated two late 19th-century methods for capturing magnetic field images from iron filings for historical insight into the pedagogy of hands-on physics education methods, and to flesh out teaching and learning practicalities tacit in the historical record. Both methods offer opportunities for close sensory engagement in data-collection…

  5. Monte Carlo method for magnetic impurities in metals

    Science.gov (United States)

    Hirsch, J. E.; Fye, R. M.

    1986-01-01

    The paper discusses a Monte Carlo algorithm to study properties of dilute magnetic alloys; the method can treat a small number of magnetic impurities interacting wiith the conduction electrons in a metal. Results for the susceptibility of a single Anderson impurity in the symmetric case show the expected universal behavior at low temperatures. Some results for two Anderson impurities are also discussed.

  6. Manufacturing methods and magnetic characteristics of magnetic wood

    International Nuclear Information System (INIS)

    Oka, H.; Hojo, A.; Osada, H.; Namizaki, Y.; Taniuchi, H.

    2004-01-01

    The relationship between wood construction and DC magnetic characteristics for three types of magnetic wood was experimentally investigated. The results show that the magnetic characteristics of each type of magnetic wood are dependent on the magnetic materials, the density of the magnetic material and the construction of the wood. Furthermore, it was determined that the relationship between the fiber direction and the magnetic path direction of the magnetic wood influenced the wood's magnetic characteristics

  7. A comparative uncertainty study of the calibration of macrolide antibiotic reference standards using quantitative nuclear magnetic resonance and mass balance methods

    International Nuclear Information System (INIS)

    Liu Shuyu; Hu Changqin

    2007-01-01

    This study introduces the general method of quantitative nuclear magnetic resonance (qNMR) for the calibration of reference standards of macrolide antibiotics. Several qNMR experimental conditions were optimized including delay, which is an important parameter of quantification. Three kinds of macrolide antibiotics were used to validate the accuracy of the qNMR method by comparison with the results obtained by the high performance liquid chromatography (HPLC) method. The purities of five common reference standards of macrolide antibiotics were measured by the 1 H qNMR method and the mass balance method, respectively. The analysis results of the two methods were compared. The qNMR is quick and simple to use. In a new medicine research and development process, qNMR provides a new and reliable method for purity analysis of the reference standard

  8. Magnetic study of iron sorbitol

    Energy Technology Data Exchange (ETDEWEB)

    Lazaro, F.J. E-mail: osoro@posta.unizar.es; Larrea, A.; Abadia, A.R.; Romero, M.S

    2002-09-01

    A magnetic study of iron sorbitol, an iron-containing drug to treat the iron deficiency anemia is presented. Transmission electron microscopy reveals that the system contains nanometric particles with an average diameter of 3 nm whose composition is close to two-line ferrihydrite. The characterisation by magnetisation and AC susceptibility measurements indicates superparamagnetic behaviour with progressive magnetic blocking starting at 8 K. The quantitative analysis of the magnetic results indicates that the system consists of an assembly of very small magnetic moments, presumably originated by spin uncompensation of the antiferromagnetic nanoparticles, with Arrhenius type magnetic dynamics.

  9. Magnetic field computations of the magnetic circuits with permanent magnets by infinite element method

    International Nuclear Information System (INIS)

    Hahn, Song Yop

    1985-01-01

    A method employing infinite elements is described for the magnetic field computations of the magnetic circuits with permanent magnet. The system stiffness matrix is derived by a variational approach, while the interfacial boundary conditions between the finite element regions and the infinite element regions are dealt with using collocation method. The proposed method is applied to a simple linear problems, and the numerical results are compared with those of the standard finite element method and the analytic solutions. It is observed that the proposed method gives more accurate results than those of the standard finite element method under the same computing efforts. (Author)

  10. 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.

  11. Methods for Probing Magnetic Films with Neutrons

    Science.gov (United States)

    Kozhevnikov, S. V.; Ott, F.; Radu, F.

    2018-03-01

    We review various methods in the investigation of magnetic films with neutrons, including those based on the effects of Larmor precession, Zeeman spatial splitting of the beam, neutron spin resonance, and polarized neutron channeling. The underlying principles, examples of the investigated systems, specific features, applications, and perspectives of these methods are discussed.

  12. Magnetic structures: neutron diffraction studies

    International Nuclear Information System (INIS)

    Bouree-Vigneron, F.

    1990-01-01

    Neutron diffraction is often an unequivocal method for determining magnetic structures. Here we present some typical examples, stressing the sequence through experiments, data analysis, interpretation and modelisation. Two series of compounds are chosen: Tb Ni 2 Ge 2 and RBe 13 (R = Gd, Tb, Dy, Ho, Er). Depending on the nature of the elements, the magnetic structures produced can be commensurate, incommensurate or even show a transition between two such phases as a function of temperature. A model, taking magnetic exchange and anisotropy into account, will be presented in the case of commensurate-incommensurate magnetic transitions in RBe 13

  13. The Compensation Method of Vehicle Magnetic Interference for the Magnetic Gradiometer

    OpenAIRE

    Lv, Junwei; Yu, Zhentao; Huang, Jingli; Zhou, Jing

    2013-01-01

    The magnetic interference of vehicle imposes a strong influence on the magnetic gradiometer. Based on the mechanism of the vehicle magnetic interference, we firstly use the difference algorithm of the magnetic gradient tensor to fuse the magnetic interference of each vector magnetometer and establish a mathematical model of vehicle magnetic interference for the magnetic gradiometer. Next, we propose a compensation method for the vehicle magnetic interference and a recognition method for the e...

  14. Structural and magnetic study of CoCr{sub 2}O{sub 4} thin films obtained by employing the sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Del Toro, A.D.; Garcia, R.P.; Davila, Y.G.; Gomes, J.L.; Goncalves, L.P.; Hernandez, E.P. [Universidade Federal de Pernambuco (UFPE), PE (Brazil)

    2016-07-01

    Full text: In this work we made a study about the structural and magnetic properties of cobalt chromite. We obtained samples in a film format and also in chromite nanopowder. Both, the powder and films were fabricated by the sol-gel chemical method, the film were deposited by the spin coating technique followed by an appropriate heat treatment at 500 °C. The used substrate was glass based on silica and we studied the rotating speed parameter during deposition. The initial aim of the work was the study of the influence of rotating speed on the quality of cromite films. The crystallinity of samples was confirmed by diffraction X-ray (XRD). The lattice parameters were determined using the Rietveld method from which we calculate grain size of 8.6 nm. The scanning electron microscopy (SEM) showed granular films with good homogeneity and we observed the dependence of the rotating speed on the quality of the deposited films. The magnetic properties were measured using a vibrating sample magnetometer (VSM). For powder samples we obtained Curie temperature of 94 K, which is a phase transition from ferrimagnetic to paramagnetic. The applied magnetic field during in the characterization of the film was oriented parallel to the plane of the substrate and we observed a high coercivity. The Curie temperature value for the films was 93 K, similar to the powder samples. (author)

  15. Nuclear magnetic resonance method and apparatus

    International Nuclear Information System (INIS)

    Young, I.R.

    1983-01-01

    In a method of investigating the distribution of a quantity in a chosen region of a body (E) by nuclear magnetic resonance techniques movement of the body during the investigation is monitored by probes (A, B C) (C extends orthogonally to A and B) attached to the body and responsive to magnetic fields applied to the body during the investigation. An apparatus for carrying out the method is also described. If movement is detected, due compensation may be made during processing of the collected data, or the latter may be re-ascertained after appropriate adjustment e.g. a change in the RF excitation frequency. (author)

  16. 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.

  17. New methods of magnet-based instrumentation for NOTES.

    Science.gov (United States)

    Magdeburg, Richard; Hauth, Daniel; Kaehler, Georg

    2013-12-01

    Laparoscopic surgery has displaced open surgery as the standard of care for many clinical conditions. NOTES has been described as the next surgical frontier with the objective of incision-free abdominal surgery. The principal challenge of NOTES procedures is the loss of triangulation and instrument rigidity, which is one of the fundamental concepts of laparoscopic surgery. To overcome these problems necessitates the development of new instrumentation. material and methods: We aimed to assess the use of a very simple combination of internal and external magnets that might allow the vigorous multiaxial traction/counter-traction required in NOTES procedures. The magnet retraction system consisted of an external magnetic assembly and either small internal magnets attached by endoscopic clips to the designated tissue (magnet-clip-approach) or an endoscopic grasping forceps in a magnetic deflector roll (magnet-trocar-approach). We compared both methods regarding precision, time and efficacy by performing transgastric partial uterus resections with better results for the magnet-trocar-approach. This proof-of-principle animal study showed that the combination of external and internal magnets generates sufficient coupling forces at clinically relevant abdominal wall thicknesses, making them suitable for use and evaluation in NOTES procedures, and provides the vigorous multiaxial traction/counter-traction required by the lack of additional abdominal trocars.

  18. Ammonia synthesis using magnetic induction method (MIM)

    Science.gov (United States)

    Puspitasari, P.; Razak, J. Abd; Yahya, N.

    2012-09-01

    The most challenging issues for ammonia synthesis is to get the high yield. New approach of ammonia synthesis by using Magnetic Induction Method (MIM) and the Helmholtz Coils has been proposed. The ammonia detection was done by using Kjeldahl Method and FTIR. The system was designed by using Autocad software. The magnetic field of MIM was vary from 100mT-200mT and the magnetic field for the Helmholtz coils was 14mT. The FTIR result shows that ammonia has been successfully formed at stretching peaks 1097,1119,1162,1236, 1377, and 1464 cm-1. UV-VIS result shows the ammonia bond at 195nm of wavelength. The ammonia yield was increase to 244.72μmole/g.h by using the MIM and six pairs of Helmholtz coils. Therefore this new method will be a new promising method to achieve the high yield ammonia at ambient condition (at 25δC and 1atm), under the Magnetic Induction Method (MIM).

  19. Optimal design method for magnetization directions of a permanent magnet array

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jae Seok [Center for Information Storage Device, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Yoo, Jeonghoon, E-mail: yoojh@yonsei.ac.k [School of Mechanical Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

    2010-08-15

    In many magnetic systems, the permanent magnet (PM) pattern has a great influence on their performance. This study proposes a systematic optimization method for designing discrete magnetization directions. While previous works have been mostly dependent on researchers' intuition, the developed method is systematic and can be applied to a two-dimensional PM-type eddy current brake model. The effectiveness of the method is confirmed, where the design's aim is to maximize the braking force on a moving conductor. The sensitivity analysis is accomplished by the adjoint variable method and the sequential linear programming is used as an optimizer. Several optimization results for various conditions through the proposed design method are compared to each other and the optimal magnet configuration for an eddy current brake is suggested.

  20. Magnetic microwires a magneto-optical study

    CERN Document Server

    Chizhik, Alexander

    2014-01-01

    PrefaceKerr Effect as Method of Investigation of Magnetization Reversal in Magnetic Wires Cold-Drawn Fe-Rich Amorphous Wire Conventional Co-Rich Amorphous WireInteraction Between Glass-Covered MicrowiresCircular Magnetic Bistability in Co-Rich Amorphous Microwires Effect of High-Frequency Driving Current on Magnetization Reversal in Co-Rich Amorphous MicrowiresRelation Between Surface Magnetization Reversal and Magnetoimpedance Helical Magnetic Structure Magnetization Reversal in Crossed Magnetic Field Visualization of Barkhausen Jump Magnetizatio

  1. Numerical simulation of bubble deformation in magnetic fluids by finite volume method

    International Nuclear Information System (INIS)

    Yamasaki, Haruhiko; Yamaguchi, Hiroshi

    2017-01-01

    Bubble deformation in magnetic fluids under magnetic field is investigated numerically by an interface capturing method. The numerical method consists of a coupled level-set and VOF (Volume of Fluid) method, combined with conservation CIP (Constrained Interpolation Profile) method with the self-correcting procedure. In the present study considering actual physical properties of magnetic fluid, bubble deformation under given uniform magnetic field is analyzed for internal magnetic field passing through a magnetic gaseous and liquid phase interface. The numerical results explain the mechanism of bubble deformation under presence of given magnetic field. - Highlights: • A magnetic field analysis is developed to simulate the bubble dynamics in magnetic fluid with two-phase interface. • The elongation of bubble increased with increasing magnetic flux intensities due to strong magnetic normal force. • Proposed technique explains the bubble dynamics, taking into account of the continuity of the magnetic flux density.

  2. Numerical methods in electron magnetic resonance

    International Nuclear Information System (INIS)

    Soernes, A.R.

    1998-01-01

    The focal point of the thesis is the development and use of numerical methods in the analysis, simulation and interpretation of Electron Magnetic Resonance experiments on free radicals in solids to uncover the structure, the dynamics and the environment of the system

  3. Numerical methods in electron magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Soernes, A.R

    1998-07-01

    The focal point of the thesis is the development and use of numerical methods in the analysis, simulation and interpretation of Electron Magnetic Resonance experiments on free radicals in solids to uncover the structure, the dynamics and the environment of the system.

  4. A study on native defects and magnetic properties in undoped rutile TiO2 using LDA and LDA+UO p+UTi d methods

    Science.gov (United States)

    Shi, Li-Bin; Wang, Yong Ping

    2016-05-01

    The native defects and magnetic properties in undoped rutile TiO2 are studied using local density approximation (LDA) and LDA adding Hubbard parameters (U) schemes. The band gap is adjusted to experimental value of 3.0 eV by combination of UTi d=4.2 eV and UO p=4.8 eV. This LDA+U methodology overcomes the band-gap problem and renders the approach more predictive. The formation energies of oxygen vacancy (VO), oxygen interstitial (Oi), titanium vacancy (VTi), titanium interstitial (Tii), oxygen anti-sites (OTi), and titanium anti-sites (TiO) are investigated by the LDA and LDA+U methods. In addition, some ground state configurations can be obtained by optimization of total spin. It is found that native defects can induce spin polarization and produce magnetic moment.

  5. The freezing of water bonded in the wheat (Triticum aestivum L.) grain studied by means protons magnetic relaxation method

    International Nuclear Information System (INIS)

    Haranczyk, H.; Jasinski, G.; Strzalka, K.

    1994-01-01

    Some biological aspects of water freezing in the wheat grain have been studied using NMR methods. Measuring of the relaxation times for freezing and liquid water shown absence of T 2 ∼100 μs and T 2 ∼1 ms separated components what pointed for some different way of water bonding

  6. Quantitative Evaluation of the Total Magnetic Moments of Colloidal Magnetic Nanoparticles: A Kinetics-based Method.

    Science.gov (United States)

    Liu, Haiyi; Sun, Jianfei; Wang, Haoyao; Wang, Peng; Song, Lina; Li, Yang; Chen, Bo; Zhang, Yu; Gu, Ning

    2015-06-08

    A kinetics-based method is proposed to quantitatively characterize the collective magnetization of colloidal magnetic nanoparticles. The method is based on the relationship between the magnetic force on a colloidal droplet and the movement of the droplet under a gradient magnetic field. Through computational analysis of the kinetic parameters, such as displacement, velocity, and acceleration, the magnetization of colloidal magnetic nanoparticles can be calculated. In our experiments, the values measured by using our method exhibited a better linear correlation with magnetothermal heating, than those obtained by using a vibrating sample magnetometer and magnetic balance. This finding indicates that this method may be more suitable to evaluate the collective magnetism of colloidal magnetic nanoparticles under low magnetic fields than the commonly used methods. Accurate evaluation of the magnetic properties of colloidal nanoparticles is of great importance for the standardization of magnetic nanomaterials and for their practical application in biomedicine. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Enhanced method of magnetic powder alignment for production of PLP Nd-Fe-B magnets

    Energy Technology Data Exchange (ETDEWEB)

    Popov, A.G. [M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, Str. S. Kovalevskoy, 18, 620137 Ekaterinburg (Russian Federation); Institute of Natural Sciences and Mathematics, Ural Federal University, Av. Mira, 19, 620002 Ekaterinburg (Russian Federation); Golovnia, O.A., E-mail: golovnya@imp.uran.ru [M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, Str. S. Kovalevskoy, 18, 620137 Ekaterinburg (Russian Federation); Institute of Natural Sciences and Mathematics, Ural Federal University, Av. Mira, 19, 620002 Ekaterinburg (Russian Federation); Protasov, A.V. [M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, Str. S. Kovalevskoy, 18, 620137 Ekaterinburg (Russian Federation); Institute of Natural Sciences and Mathematics, Ural Federal University, Av. Mira, 19, 620002 Ekaterinburg (Russian Federation)

    2017-04-15

    It is demonstrated how the high degree of powder alignment in PLP magnets can be achieved by loading the powder into a container placed in a magnetic field of moderate strength. The strip-cast alloy with a composition of 30.00 Nd, 1.95 Dy, 66.42 Fe, 0.99 B, 0.54 Co, 0.1 Ga (wt%) was subjected to hydrogen decrepitation and then milled in a vibratory mill in toluene to an average particle size of 2.9 µm determined by the FSSS method. The powder was compacted in the magnetic field of 0.2 – 1.2 T to the filling density 2.6 – 3.2×10{sup 3} kg/m{sup 3}. It is shown that loading the powder into a container placed in a magnetic field enhances the degree of powder alignment in sintered Nd-Fe-B magnets produced from non-pressed powder. At the filling density less than 3.2×10{sup 3} kg/m{sup 3}, the density of magnets is high but insufficient, because of the formation of magnetostatic chains of particles, which impedes the powder compaction. The simulation by the discrete-element method qualitatively proves that the magnetostatic interaction of the chains of particles that are formed in the course of loading in the magnetic field stimulates a decrease in the density of the sintered magnets and its non-uniform distribution over the sample. As a result of the optimization of the parameters of the alignment and compaction of the powder loaded in a magnetic field, PLP magnets with B{sub r} ≥1.34 T, H{sub c} ≥950 kA/m, (BH){sub max} ≥340 kJ/m{sup 3}, and the degree of alignment exceeding 96% were produced. - Highlights: • The pressless process (PLP) in magnet production is studied. • A new method of the loading of powder in an applied DC magnetic field is suggested. • The method allows achieving higher degree of alignment in moderate magnetic field. • Density of sintered magnets is studied experimentally and via DEM simulation. • Low density is caused by the formation of magnetostatic chains of powder particles.

  8. Enhanced method of magnetic powder alignment for production of PLP Nd-Fe-B magnets

    International Nuclear Information System (INIS)

    Popov, A.G.; Golovnia, O.A.; Protasov, A.V.

    2017-01-01

    It is demonstrated how the high degree of powder alignment in PLP magnets can be achieved by loading the powder into a container placed in a magnetic field of moderate strength. The strip-cast alloy with a composition of 30.00 Nd, 1.95 Dy, 66.42 Fe, 0.99 B, 0.54 Co, 0.1 Ga (wt%) was subjected to hydrogen decrepitation and then milled in a vibratory mill in toluene to an average particle size of 2.9 µm determined by the FSSS method. The powder was compacted in the magnetic field of 0.2 – 1.2 T to the filling density 2.6 – 3.2×10 3 kg/m 3 . It is shown that loading the powder into a container placed in a magnetic field enhances the degree of powder alignment in sintered Nd-Fe-B magnets produced from non-pressed powder. At the filling density less than 3.2×10 3 kg/m 3 , the density of magnets is high but insufficient, because of the formation of magnetostatic chains of particles, which impedes the powder compaction. The simulation by the discrete-element method qualitatively proves that the magnetostatic interaction of the chains of particles that are formed in the course of loading in the magnetic field stimulates a decrease in the density of the sintered magnets and its non-uniform distribution over the sample. As a result of the optimization of the parameters of the alignment and compaction of the powder loaded in a magnetic field, PLP magnets with B r ≥1.34 T, H c ≥950 kA/m, (BH) max ≥340 kJ/m 3 , and the degree of alignment exceeding 96% were produced. - Highlights: • The pressless process (PLP) in magnet production is studied. • A new method of the loading of powder in an applied DC magnetic field is suggested. • The method allows achieving higher degree of alignment in moderate magnetic field. • Density of sintered magnets is studied experimentally and via DEM simulation. • Low density is caused by the formation of magnetostatic chains of powder particles.

  9. Method for obtaining large levitation pressure in superconducting magnetic bearings

    Science.gov (United States)

    Hull, John R.

    1996-01-01

    A method and apparatus for compressing magnetic flux to achieve high levitation pressures. Magnetic flux produced by a magnetic flux source travels through a gap between two high temperature superconducting material structures. The gap has a varying cross-sectional area to compress the magnetic flux, providing an increased magnetic field and correspondingly increased levitation force in the gap.

  10. Apparatus and method for handling magnetic particles in a fluid

    Science.gov (United States)

    Holman, David A.; Grate, Jay W.; Bruckner-Lea, Cynthia J.

    2000-01-01

    The present invention is an apparatus and method for handling magnetic particles suspended in a fluid, relying upon the known features of a magnetic flux conductor that is permeable thereby permitting the magnetic particles and fluid to flow therethrough; and a controllable magnetic field for the handling. The present invention is an improvement wherein the magnetic flux conductor is a monolithic porous foam.

  11. Study of axial magnetic effect

    Energy Technology Data Exchange (ETDEWEB)

    Braguta, Victor [IHEP, Protvino, Moscow region, 142284 Russia ITEP, B. Cheremushkinskaya street 25, Moscow, 117218 (Russian Federation); School of Biomedicine, Far Eastern Federal University, Ajax 10 Building 25, Russian island, Vladivostok, 690922 (Russian Federation); Chernodub, M. N. [CNRS, Laboratoire de Mathématiques et Physique Théorique, Université François-Rabelais Tours, Fédération Denis Poisson, Parc de Grandmont, 37200 Tours, France Department of Physics and Astronomy, University of Gent, Krijgslaan 281, S9, B-9000 Gent (Belgium); School of Biomedicine, Far Eastern Federal University, Ajax 10 Building 25, Russian island, Vladivostok, 690922 (Russian Federation); Goy, V. A. [School of Natural Sciences, Far Eastern Federal University, Sukhanova street 8, Vladivostok, 690950 (Russian Federation); Landsteiner, K. [Instituto de Física Teórica UAM/CSIC, C/ Nicolás Cabrera 13-15, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Molochkov, A. V. [School of Biomedicine, Far Eastern Federal University, Ajax 10 Building 25, Russian island, Vladivostok, 690922 (Russian Federation); Ulybyshev, M. [ITEP, B. Cheremushkinskaya street 25, Moscow, 117218 Russia Institute for Theoretical Problems of Microphysics, Moscow State University, Moscow, 119899 (Russian Federation)

    2016-01-22

    The Axial Magnetic Effect manifests itself as an equilibrium energy flow of massless fermions induced by the axial (chiral) magnetic field. Here we study the Axial Magnetic Effect in the quenched SU(2) lattice gauge theory with massless overlap fermions at finite temperature. We numerically observe that in the low-temperature hadron phase the effect is absent due to the quark confinement. In the high-temperature deconfinement phase the energy flow is an increasing function of the temperature which reaches the predicted asymptotic T{sup 2} behavior at high temperatures. We find, however, that energy flow is about one order of magnitude lower compared to a theoretical prediction.

  12. Structural, optical and magnetic study of (1-x)ZnO-xMgO composites prepared through solid state reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Adhlakha, Nidhi [Smart Materials Research Laboratory, Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Yadav, K.L., E-mail: klyadav35@yahoo.com [Smart Materials Research Laboratory, Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Kumar, Amit; Patel, Piyush Kumar; Rani, Jyoti; Rawat, Meera [Smart Materials Research Laboratory, Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2012-09-01

    We report the study of structural, optical and magnetic properties of (1-x)ZnO-xMgO (x=0.35, 0.40, 0.45 and 0.50) composites prepared by solid state reaction method. X-ray diffraction pattern confirms the presence of both the phases associated with ZnO (hexagonal) and MgO (cubic), which is revealed through the existence of (1 1 1) and (2 0 0) peaks in addition to ZnO peaks. The lattice parameter c as calculated using X-ray analysis undergoes shrinkage with increasing content of MgO. Microstructural analysis suggests that there is no variation in spherical elongated shape of grains with increasing concentration of MgO, where the average grain size is found to be {approx}600 nm. The band gap as calculated from optical absorption spectra obtained by diffuse reflectance method recorded at room temperature is tuned from 3.16 to 3.55 eV. Photoluminescence spectra consist of near band edge UV emission (389 nm) and defect level emission (503 nm). The increase of MgO concentration leads to blue shift of UV emission peaks. The magnetic measurements conducted using SQUID at 5 K temperature reveals ferromagnetism along with paramagnetic and superparamagnetic components. Saturation magnetisation (M{sub s}) is observed to be enhanced with MgO doping.

  13. Method and apparatus for control of a magnetic structure

    Science.gov (United States)

    Challenger, Michael P.; Valla, Arthur S.

    1996-06-18

    A method and apparatus for independently adjusting the spacing between opposing magnet arrays in charged particle based light sources. Adjustment mechanisms between each of the magnet arrays and the supporting structure allow the gap between the two magnet arrays to be independently adjusted. In addition, spherical bearings in the linkages to the magnet arrays permit the transverse angular orientation of the magnet arrays to also be adjusted. The opposing magnet arrays can be supported above the ground by the structural support.

  14. Superconductive energy storage magnet study

    International Nuclear Information System (INIS)

    Rhee, S.W.

    1982-01-01

    Among many methods of energy storages the superconducting energy storage has been considered as the most promising method. Many related technical problems are still unsolved. One of the problems is the magnetizing and demagnetizing loss of superconducting coil. This loss is mainly because of hysteresis of pinning force. In this paper the hysteresis loss is calculated and field dependence of the a.c. losses is explained. The ratio of loss and stored energy is also calculated. (Author)

  15. Error studies of Halbach Magnets

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-03-02

    These error studies were done on the Halbach magnets for the CBETA “First Girder” as described in note [CBETA001]. The CBETA magnets have since changed slightly to the lattice in [CBETA009]. However, this is not a large enough change to significantly affect the results here. The QF and BD arc FFAG magnets are considered. For each assumed set of error distributions and each ideal magnet, 100 random magnets with errors are generated. These are then run through an automated version of the iron wire multipole cancellation algorithm. The maximum wire diameter allowed is 0.063” as in the proof-of-principle magnets. Initially, 32 wires (2 per Halbach wedge) are tried, then if this does not achieve 1e-­4 level accuracy in the simulation, 48 and then 64 wires. By “1e-4 accuracy”, it is meant the FOM defined by √(Σn≥sextupole an 2+bn 2) is less than 1 unit, where the multipoles are taken at the maximum nominal beam radius, R=23mm for these magnets. The algorithm initially uses 20 convergence interations. If 64 wires does not achieve 1e-­4 accuracy, this is increased to 50 iterations to check for slow converging cases. There are also classifications for magnets that do not achieve 1e-4 but do achieve 1e-3 (FOM ≤ 10 units). This is technically within the spec discussed in the Jan 30, 2017 review; however, there will be errors in practical shimming not dealt with in the simulation, so it is preferable to do much better than the spec in the simulation.

  16. Study of one dimensional magnetic system via field theory

    International Nuclear Information System (INIS)

    Talim, S.L.

    1988-04-01

    We present a study of one-dimensional magnetic system using field theory methods. We studied the discreteness effects in a classical anisotropic one dimensional antiferromagnet in an external magnetic field. It is shown that for TMMC, at the temperatures and magnetic fields where most experiments have been done, the corrections are small and can be neglected. (author)

  17. Dual stage active magnetic regenerator and method

    Science.gov (United States)

    Pecharsky, Vitalij K.; Gschneidner, Jr., Karl A.

    1999-03-30

    A dual stage active magnetic regenerator refrigerator as well as method using the Joule-Brayton thermodynamic cycle includes a high temperature stage refrigerant comprising DyAl.sub.2 or (Dy.sub.1-x Er.sub.x)Al.sub.2 where x is selected to be greater than 0 and less than about 0.3 in combination with a low temperature stage comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 where x is selected to be greater than about 0.5 and less than 1 to provide significantly improved refrigeration efficiency in the liquefaction of gaseous hydrogen.

  18. Magnetic-relaxation method of analysis of inorganic substances

    International Nuclear Information System (INIS)

    Popel', A.A.

    1978-01-01

    The magnetic-relaxation method is considered of the quantitative analysis of inorganic substances based on time dependence of magnetic nuclei relaxation on the quantity of paramagnetic centres in a solution. The characteristic is given of some methods of measuring nuclear magnetic relaxation times: method of weak oscillation generator and pulse methods. The effect of temperature, general solution viscosity, diamagnetic salt concentration, medium acidity on nuclear relaxation velocity is described. The determination sensitivity is estimated and the means of its increase definable concentration intervals and method selectivity are considered. The method application when studying complexing in the solution is described. A particular attention is given to the investigation of heteroligand homocentre, heterocentre and protonated complexes as well as to the problems of particle exchange of the first coordination sphere with particles from the mass of solution. The equations for equilibrium constant calculation in different systems are given. Possibilities of determining diamagnetic ions by the magnetic-relaxation method using paramagnetic indicators are confirmed by the quantitative analysis of indium, gallium, thorium and scandium in their salt solutions

  19. 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.

  20. Study on magnetic field mapping within cylindrical center volume of general magnet

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Li; Lee, Sang Jin [Uiduk University, Gyeongju (Korea, Republic of)

    2016-06-15

    For the magnetic field analysis or design, it is important to know the behavior of the magnetic field in an interesting space. Magnetic field mapping becomes a useful tool for the study of magnetic field. In this paper, a numerical way for mapping the magnetic field within the cylindrical center volume of magnet is presented, based on the solution of the Laplace's equation in the cylindrical coordinate system. The expression of the magnetic field can be obtained by the magnetic flux density, which measured in the mapped volume. According to the form of the expression, the measurement points are arranged with the parallel cylindrical line (PCL) method. As example, the magnetic flux density generated by an electron cyclotron resonance ion source (ECRIS) magnet and a quadrupole magnet were mapped using the PCL method, respectively. The mapping results show the PCL arrangement method is feasible and convenience to map the magnetic field within a cylindrical center volume generated by the general magnet.

  1. Patterning nanostructures to study magnetization processes

    International Nuclear Information System (INIS)

    Atkinson, D

    2005-01-01

    Lithography techniques such as electron-beam lithography and focused-ion-beam milling are widely used to fabricate structures with dimensions well below 1 μm. These techniques have been used to produce planar magnetic structures with sub-micrometer dimensions and well controlled geometry. This has allowed the study of basic magnetic behaviour and the development of structures with potential for applications in magnetic recording and magnetic logic devices. The techniques of electron beam lithography and focused-ion-beam milling for the fabrication of magnetic nanostructures are outlined here. These techniques have been used to fabricate ribbon-like planar nanowires to study the behaviour of the individual magnetic domain walls which mediate the reversal process in such elongated structures. These methods allow the production of structures in which the location of domain wall formation and position can be controlled, allowing separation and study of the domain wall nucleation and propagation processes. Domain wall injection and domain wall propagation behaviour are investigated and shown to be stochastic processes

  2. Monitoring angiogenesis using magnetic resonance methods

    DEFF Research Database (Denmark)

    Holm, David Alberg

    2008-01-01

    When a tumor reaches a certain size it can no longer rely on passive perfusion for nutrition. The tumor therefore emits signaling molecules which stimulating surrounding vessels to divide and grow towards the tumor, a process known as angiogenesis. Very little angiogenesis is present in healthy...... adults where it is primaily found in wound healing, pregnancy and during the menstrual cycle. This thesis focus on the negative consequences of angiogenesis in cancer. It consists of a an initial overview followed by four manuscripts. The overview gives a short introduction to the process of angiogenesis...... and the involved signaling molecules. Subsequently, a short review of contrast agents and perfusion measurements is given. Finally, methods for monitoring angiogenesis using magnetic resonance imaging are reviewed. A method for monitoring early stages of angiogenesis as well as the effect of anti...

  3. Correlations between the orientation of magnetic recording media determined by Moessbauer spectroscopy and magnetic methods

    International Nuclear Information System (INIS)

    Pott, R.A.; Koch, W.; Leitner, L.

    1986-01-01

    The orientation of the easy magnetization axis of magnetic particles is a key parameter of the recording performance of magnetic recording media. Usually the orientation is measured by magnetic methods, but the applicability of the Moessbauer Spectroscopy has also been shown in the past. The authors show and discuss the correlations between the results obtained by magnetic and Moessbauer measurements for the example of several magnetic tapes. They demonstrate that by a combination of both methods one is even able to estimate the mean canting angles distribution width of the easy axis of magnetization. (Auth.)

  4. Magnetic resonance studies of solid polymers

    International Nuclear Information System (INIS)

    Lenk, R.

    1969-01-01

    This paper is a review of the application of nuclear magnetic resonance (NMR) to solid polymers. In the first, theoretical part, the elements of the theory of NMR, which are necessary for the study of the properties of solid polymers are discussed: the moments method, nuclear relaxation and the distribution of correlation times. In the second part the experimental results are presented. (author) [fr

  5. A simulation study of a method to reduce positron annihilation spread distributions using a strong magnetic field in positron emission tomography

    International Nuclear Information System (INIS)

    Iida, H.; Kanno, I.; Miura, S.; Murakami, M.; Takahashi, V.; Kemura, K.

    1986-01-01

    The positron trajectories have been three-dimensionally simulated using a Monte-Carlo method under various strength of the magnetic field. More than 5 tesla of the field confined the positrons effectively, resulting in increase of the probability of the annihilation within a limited small region, hence the higher spatial resolution in positron emission tomography

  6. Development of a Magnetic Attachment Method for Bionic Eye Applications.

    Science.gov (United States)

    Fox, Kate; Meffin, Hamish; Burns, Owen; Abbott, Carla J; Allen, Penelope J; Opie, Nicholas L; McGowan, Ceara; Yeoh, Jonathan; Ahnood, Arman; Luu, Chi D; Cicione, Rosemary; Saunders, Alexia L; McPhedran, Michelle; Cardamone, Lisa; Villalobos, Joel; Garrett, David J; Nayagam, David A X; Apollo, Nicholas V; Ganesan, Kumaravelu; Shivdasani, Mohit N; Stacey, Alastair; Escudie, Mathilde; Lichter, Samantha; Shepherd, Robert K; Prawer, Steven

    2016-03-01

    Successful visual prostheses require stable, long-term attachment. Epiretinal prostheses, in particular, require attachment methods to fix the prosthesis onto the retina. The most common method is fixation with a retinal tack; however, tacks cause retinal trauma, and surgical proficiency is important to ensure optimal placement of the prosthesis near the macula. Accordingly, alternate attachment methods are required. In this study, we detail a novel method of magnetic attachment for an epiretinal prosthesis using two prostheses components positioned on opposing sides of the retina. The magnetic attachment technique was piloted in a feline animal model (chronic, nonrecovery implantation). We also detail a new method to reliably control the magnet coupling force using heat. It was found that the force exerted upon the tissue that separates the two components could be minimized as the measured force is proportionately smaller at the working distance. We thus detail, for the first time, a surgical method using customized magnets to position and affix an epiretinal prosthesis on the retina. The position of the epiretinal prosthesis is reliable, and its location on the retina is accurately controlled by the placement of a secondary magnet in the suprachoroidal location. The electrode position above the retina is less than 50 microns at the center of the device, although there were pressure points seen at the two edges due to curvature misalignment. The degree of retinal compression found in this study was unacceptably high; nevertheless, the normal structure of the retina remained intact under the electrodes. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  7. Studies in perpendicular magnetic recording

    Science.gov (United States)

    Valcu, Bogdan F.

    This dissertation uses both micromagnetic simulation and analytical methods to analyze several aspects of a perpendicular recording system. To increase the head field amplitude, the recording layer is grown on top of a soft magnetic layer (keeper). There is concern about the ability of the keeper to conduct the magnetic flux from the head at high data rates. We compute numerically the magnetization motion of the soft underlayer during the reversal process. Generation of non-linear spin waves characterizes the magnetization dynamics in the keeper, the spins are oscillating with a frequency higher than that of the reversal current. However, the recording field applied to the data layer follows the time dependence of the input wave form. The written transition shape is determined by the competition between the head field gradient and the demagnetizing field gradient. An analytical slope model that takes into consideration the angular orientation of the applied field is used to estimate the transition parameter; agreement is shown with the micromagnetic results. On the playback side, the reciprocity principle is applied to calculate the read out signal from a single magnetic transition in the perpendicular medium. The pulse shape is close to an error-function, going through zero when the sensor is above the transition center and decaying from the peak to an asymptotic value when the transition center is far away. Analytical closed forms for both the slope in the origin and the asymptotic value show the dependence on the recording geometry parameters. The Signal-to-Noise Ratio is calculated assuming that the noise is dominated by the medium jitter. To keep the SNR at a readable level while increasing the areal density, the average magnetic grain diameter must decrease; consequently grain size fluctuations will affect the thermal decay. We performed Transmission Electron Microscopy measurements and observed differences in the grain size distribution between various types

  8. Magnetic study of the Furnas caldera (Azores

    Directory of Open Access Journals (Sweden)

    J. M. Torta

    1997-06-01

    Full Text Available A local ground magnetic study of the Furnas caldera (S. Miguel Island, Azores has provided new insight into the magnetic structure of this volcano. Analysis of the data comprised removal of the IGRF, reduction to the pole, pseudogravity integration and upward continuation. Also, a spectral method was applied to estimate the depth to the magnetic sources, as well as a 2.5D forward modelling technique. Magnetic properties obtained at the laboratory for some representative sample rocks were considered in the modelling process. The most relevant features are the existence of an important negative anomaly inside the caldera and of an intense positive anomaly to the south of the coast. The former points out a decrease in the magnetization of the caldera filling materials with respect to the surrounding rocks, which could be explained as the result of post-eruption processes such as hydrothermal alteration. This is expected as Furnas has an active hydrothermal system probably related with a magmatic reservoir at high temperature. The positive anomaly suggests the existence of a strongly-magnetized body beneath the south coast.

  9. Nuclear magnetic resonance studies of lipoproteins

    International Nuclear Information System (INIS)

    Hamilton, J.A.; Morrisett, J.D.

    1986-01-01

    Several nuclei in lipoproteins are magnetically active and are thus potential NMR probes of lipoprotein structure. Table I lists the magnetic isotopes preset in the covalent structures of the molecular constituents of lipoproteins: lipids, proteins, and carbohydrates. Every type of nucleus that is part of the endogenous structure of these molecules has at least one magnetic isotope. Each magnetic nucleus represents an intrinsic and completely nonperturbing probe (when at the natural abundance level) of local molecular motion and magnetic environment. The NMR experiment itself is also nonperturbing and nondestructive. Table I also lists for each nucleus its nuclear spin, its natural isotopic abundance, its sensitivity, and its resonance frequency at two commonly employed magnetic in the low field range (21.14 kG or 2.11 Tesla) and the other in the high field range (47.0 kG or 4.70 Tesla). Of the nuclei listed in Table I, /sup 1/H, /sup 13/C, and /sup 31/P have been the primary ones studied in lipoproteins. The general advantages and disadvantages afforded by these and other nuclei as probes of lipoprotein structure are discussed. /sup 13/C NMR spectroscopy, the method which has had the most extensive application (and probably has the greatest future potential) to lipoproteins, is treated in greatest detail, but many of the principles described apply to other nuclei as well

  10. Method of magnetic separation and apparatus therefore

    Science.gov (United States)

    Oder, Robin R. (Inventor)

    1991-01-01

    An apparatus for magnetically separating and collecting particulate matter fractions of a raw sample according to relative magnetic susceptibilities of each fraction so collected is disclosed. The separation apparatus includes a splitter which is used in conjunction with a magnetic separator for achieving the desired fractionation.

  11. 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

  12. On the study of the magnetic domain pattern via the initial magnetization curve

    International Nuclear Information System (INIS)

    Wu, T.

    1997-01-01

    This study inquires into the relationships between the initial magnetization curve and the magnetic domain pattern in the demagnetized states for amorphous TbFeCo as well as multilayered Co/Pd thin film samples. This was done specifically through an investigation of different demagnetized states of samples demagnetized by a variety of methods. The magnetic domain pattern for the sample demagnetized by an in-plane magnetic field and for the sample demagnetized by a perpendicular magnetic field was found to be quite different even though both states have zero magnetization. The former state has denser and finer domains than the latter. In addition, both states were studied in light of the initial magnetization curves obtained by measurements of the magneto-optic Kerr effect and the extraordinary Hall effect. Moreover, the initial magnetization for the fine domains increases with an increase in magnetic field, while for the coarse domains, the initial magnetization remains at zero for magnetic field below coercivity H c , then rises sharply to saturated magnetization when magnetic field is nearly equal to H c . copyright 1997 American Institute of Physics

  13. 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.

  14. Study of optimal flip angle for inversion-recovery gradient echo method in delayed contrast-enhanced cardiac magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ogawa, Masashi; Matsumura, Yoshio; Tsuchihashi, Toshio

    2013-01-01

    Delayed contrast-enhanced cardiac magnetic resonance imaging (MRI) is a valuable tool for detecting myocardial infarction and assessing myocardial viability. The standard viability MRI technique is the inversion-recovery gradient echo (IR-GRE) method. Several previous studies have demonstrated that this imaging technique provides superior image quality at high magnetic field strengths, e.g., 3.0 T. However, there are numerous possible flip angles. We investigated the optimal flip angle of IR-GRE in delayed contrast-enhanced cardiac MRI. Phantoms were made that modeled infarcted myocardium and normal myocardium after administration of contrast agent. To determine optimal flip angle, we compared the contrast-to-noise ratio (CNR) among these phantoms and evaluated the degree of artifacts induced by increased flip angle. The flip angle that showed the highest CNR for 2D IR-GRE and 3D IR-GRE was 30deg/15deg at 1.5 T and 25deg/15deg at 3.0 T. The flip angle that showed the highest CNR was independent of R-R interval. Streak artifacts induced by increased flip angle tended to occur more readily at 3.0 T than 1.5 T. The optimal flip angle for 2D IR-GRE and 3D IR-GRE at 1.5 T was 30deg and 15deg, respectively. At 3.0 T, taking into account the results for both CNR and streak artifacts, we concluded the optimal flip angle of 2D IR-GRE to be 15-20deg. (author)

  15. Magneto-optic studies of magnetic oxides

    Energy Technology Data Exchange (ETDEWEB)

    Gehring, Gillian A., E-mail: g.gehring@shef.ac.uk [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom); Alshammari, Marzook S.; Score, David S.; Neal, James R.; Mokhtari, Abbas; Fox, A. Mark [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom)

    2012-10-15

    A brief review of the use of magneto-optic methods to study magnetic oxides is given. A simple method to obtain the magnetic circular dichroism (MCD) of a thin film on a transparent substrate is described. The method takes full account of multiple reflections in the film and substrate. Examples of the magneto-optic spectra of Co-doped ZnO, Fe{sub 3}O{sub 4}, and GdMnO{sub 3} are given. The Maxwell-Garnett method is used to describe the effects of metallic cobalt inclusions in Co:ZnO samples, and the change of the MCD spectra of Fe{sub 3}O{sub 4} at the Verwey temperature is discussed. Data showing different MCD signals at different energies is presented for GdMnO{sub 3}.

  16. Magneto-optic studies of magnetic oxides

    International Nuclear Information System (INIS)

    Gehring, Gillian A.; Alshammari, Marzook S.; Score, David S.; Neal, James R.; Mokhtari, Abbas; Fox, A. Mark

    2012-01-01

    A brief review of the use of magneto-optic methods to study magnetic oxides is given. A simple method to obtain the magnetic circular dichroism (MCD) of a thin film on a transparent substrate is described. The method takes full account of multiple reflections in the film and substrate. Examples of the magneto-optic spectra of Co-doped ZnO, Fe 3 O 4 , and GdMnO 3 are given. The Maxwell–Garnett method is used to describe the effects of metallic cobalt inclusions in Co:ZnO samples, and the change of the MCD spectra of Fe 3 O 4 at the Verwey temperature is discussed. Data showing different MCD signals at different energies is presented for GdMnO 3 .

  17. Visual rating method and tensor-based morphometry in the diagnosis of mild cognitive impairment and Alzheimer's disease: a comparative magnetic resonance imaging study.

    Science.gov (United States)

    Tuokkola, Terhi; Koikkalainen, Juha; Parkkola, Riitta; Karrasch, Mira; Lötjönen, Jyrki; Rinne, Juha O

    2016-03-01

    Atrophy of the medial temporal lobe (MTL) is the main structural magnetic resonance imaging (MRI) finding in the brain of patients with Alzheimer's disease (AD). However, evaluating the degree of atrophy is still demanding. The visual rating method (VRM) was compared with multi-template tensor-based morphometry (TBM), in terms of its efficacy in diagnosing of mild cognitive impairment (MCI) and AD. Forty-seven patients with MCI, 80 patients with AD and 84 controls were studied. TBM seems to be more sensitive than VRM at the early stage of dementia in the areas of MTL and ventricles. The methods were equally good in distinguishing controls and the MCI group from the AD group. At the frontal areas TBM was better than VRM in all comparisons. A user-friendly VRM is still useful for the clinical evaluation of MCI patients, but multi-template TBM is more sensitive for diagnosing the early stages of dementia. However, TBM is currently too demanding to use for daily clinical work. © The Foundation Acta Radiologica 2015.

  18. Recent development in magnetic neutron scattering studies

    International Nuclear Information System (INIS)

    Endoh, Yasuo

    1993-01-01

    Neutron scattering results contain many new concepts in modern magnetism. We review here the most recent neutron magnetic scattering studies from so called '214' copper oxide lamellar materials, because a number of important developments in magnetism are condensed in this novel subject. We show that neutron scattering has played crucial role in our understanding of modern magnetism. (author)

  19. Magnetic stirring welding method applied to nuclear power plant

    International Nuclear Information System (INIS)

    Hirano, Kenji; Watando, Masayuki; Morishige, Norio; Enoo, Kazuhide; Yasuda, Yuuji

    2002-01-01

    In construction of a new nuclear power plant, carbon steel and stainless steel are used as base materials for the bottom linear plate of Reinforced Concrete Containment Vessel (RCCV) to achieve maintenance-free requirement, securing sufficient strength of structure. However, welding such different metals is difficult by ordinary method. To overcome the difficulty, the automated Magnetic Stirring Welding (MSW) method that can demonstrate good welding performance was studied for practical use, and weldability tests showed the good results. Based on the study, a new welding device for the MSW method was developed to apply it weld joints of different materials, and it practically used in part of a nuclear power plant. (author)

  20. Neutron scattering studies on frustrated magnets

    International Nuclear Information System (INIS)

    Arima, Taka-hisa

    2013-01-01

    A lot of frustrated magnetic systems exhibit a nontrivial magnetic order, such as long-wavelength modulation, noncollinear, or noncoplanar order. The nontrivial order may pave the way for the novel magnetic function of matter. Neutron studies are necessary to determine the magnetic structures in the frustrated magnetic systems. In particular, spin-polarized neutron scattering is a useful technique for the investigation of the novel physical properties relevant to the nontrivial spin arrangement. Here some neutron studies on a multiferroic perovskite manganese oxide system are demonstrated as a typical case. The frustrated magnetic systems may also a playground of novel types of local magnetic excitations, which behave like particles in contrast to the magnetic waves. It is becoming a good challenge to study such particle-type magnetic excitations relevant to the magnetic frustration. (author)

  1. [Study of the influence of uniform transverse magnetic field on the dose distribution of high energy electron beam using Monte Carlo method].

    Science.gov (United States)

    You, Shihu; Xu, Yun; Wu, Zhangwen; Hou, Qing; Guo, Chengjun

    2014-12-01

    In the present work, Monte Carlo simulations were employed to study the characteristics of the dose distribution of high energy electron beam in the presence of uniform transverse magnetic field. The simulations carried out the transport processes of the 30 MeV electron beam in the homogeneous water phantom with different magnetic field. It was found that the dose distribution of the 30 MeV electron beam had changed significantly because of the magnetic field. The result showed that the range of the electron beam was decreased obviously and it formed a very high dose peak at the end of the range, and the ratio of maximum dose to the dose of the surface was greatly increased. The results of this study demonstrated that we could change the depth dose distribution of electron beam which is analogous to the heavy ion by modulating the energy of the electron and magnetic field. It means that using magnetic fields in conjunction with electron radiation therapy has great application prospect, but it also has brought new challenges for the research of dose algorithm.

  2. Magnetic susceptibility: a proxy method of estimating increased pollution

    International Nuclear Information System (INIS)

    Kluciarova, D.; Gregorova, D.; Tunyi, I.

    2004-01-01

    A need for rapid and inexpensive (proxy) methods of outlining areas exposed to increased pollution by atmospheric particulates of industrial origin caused scientists in various fields to use and validate different non-traditional (or non-chemical) techniques. Among them, soil magnetometry seems to be a suitable tool. This method is based on the knowledge that ferrimagnetic particles, namely magnetite, are produced from pyrite during combustion of fossil fuel. Besides the combustion processes, magnetic particles can also originate from road traffic, for example, or can be included in various waste-water outlets. In our study we examine the magnetic susceptibility as a convenient measure of determining the concentration of (ferri) magnetic minerals by rapid and non-destructive means. We used for measure KLY-2 Kappabridge. Concentration of ferrimagnetic minerals in different soils is linked to pollution sources. Higher χ values were observed in soils on the territory in Istebne (47383x10 -6 SI ). The susceptibility anomaly may be caused by particular geological circumstances and can be related to high content of ferromagnetic minerals in the host rocks. Positive correlation of magnetic susceptibility are conditioned by industrial contamination mainly by metal working factories and by traffic. The proposed method can be successfully applied in determining heavy metal pollution of soils on the city territories. (authors)

  3. Improvement of a magnetization method on a small-size superconducting bulk magnet system

    International Nuclear Information System (INIS)

    Yokoyama, K.; Oka, T.; Noto, K.

    2011-01-01

    This paper proposed an effective magnetizing method of high-T c bulk superconductors. The magnetic pass was artificially formed by field-cooling using a permanent magnet. The trapped field was increased by 20-25% as compared with the conventional method. We observed that the channel was formed partially in the trapped field distribution. A pulsed-filed magnetization (PFM) is an important technique for industrial applications of superconducting bulk magnets, and several advanced PFM methods are proposed to enhance the trapped field. In the well-known IMRA method, the channel through the magnetic flux is formed by the flux flow caused by heat generation when applying the strong pulsed-field, and the magnetic flux is made to penetrate into the bulk through the channel in the following pulse application. On the other hand, large applied field leads to large heat generation, and, therefore, the trapped field is decreased greatly. This paper proposes an effective magnetizing method in which the channel composed of magnetic field is artificially formed by field-cooling (FC) using a permanent magnet and the magnetic flux by PFM is induced to the channel. To confirm the validity of this method, the bulk was magnetized by FC using Nd-Fe-B magnets of the rectangular and the ring shapes, and thereafter, a pulsed-field of 6.2 T was applied. As a result, the trapped field of the bulk magnetized by FC using the ring magnet was increased by about 20-25% as compared with that of the conventional PFM, and, moreover, it was observed that the channel was formed partially by measurement of the magnetic field distribution.

  4. Theoretical Study of H/D Isotope Effects on Nuclear Magnetic Shieldings Using an ab initio Multi-Component Molecular Orbital Method

    Directory of Open Access Journals (Sweden)

    Masanori Tachikawa

    2013-05-01

    Full Text Available We have theoretically analyzed the nuclear quantum effect on the nuclear magnetic shieldings for the intramolecular hydrogen-bonded systems of σ-hydroxy acyl aromatic species using the gauge-including atomic orbital technique combined with our multi-component density functional theory. The effect of H/D quantum nature for geometry and nuclear magnetic shielding changes are analyzed. Our study clearly demonstrated that the geometrical changes of hydrogen-bonds induced by H/D isotope effect (called geometrical isotope effect: GIE is the dominant factor of deuterium isotope effect on 13C chemical shift.

  5. Density functional studies on the exchange interaction of a dinuclear Gd(iii)-Cu(ii) complex: method assessment, magnetic coupling mechanism and magneto-structural correlations.

    Science.gov (United States)

    Rajaraman, Gopalan; Totti, Federico; Bencini, Alessandro; Caneschi, Andrea; Sessoli, Roberta; Gatteschi, Dante

    2009-05-07

    Density functional calculations have been performed on a [Gd(iii)Cu(ii)] complex [L(1)CuGd(O(2)CCF(3))(3)(C(2)H(5)OH)(2)] () (where L(1) is N,N'-bis(3-ethoxy-salicylidene)-1,2-diamino-2-methylpropanato) with an aim of assessing a suitable functional within the DFT formalism to understand the mechanism of magnetic coupling and also to develop magneto-structural correlations. Encouraging results have been obtained in our studies where the application of B3LYP on the crystal structure of yields a ferromagnetic J value of -5.8 cm(-1) which is in excellent agreement with the experimental value of -4.42 cm(-1) (H = JS(Gd).S(Cu)). After testing varieties of functional for the method assessment we recommend the use of B3LYP with a combination of an effective core potential basis set. For all electron basis sets the relativistic effects should be incorporated either via the Douglas-Kroll-Hess (DKH) or zeroth-order regular approximation (ZORA) methods. A breakdown approach has been adopted where the calculations on several model complexes of have been performed. Their wave functions have been analysed thereafter (MO and NBO analysis) in order to gain some insight into the coupling mechanism. The results suggest, unambiguously, that the empty Gd(iii) 5d orbitals have a prominent role on the magnetic coupling. These 5d orbitals gain partial occupancy via Cu(ii) charge transfer as well as from the Gd(iii) 4f orbitals. A competing 4f-3d interaction associated with the symmetry of the complex has also been observed. The general mechanism hence incorporates both contributions and sets forth rather a prevailing mechanism for the 3d-4f coupling. The magneto-structural correlations reveal that there is no unique parameter which the J values are strongly correlated with, but an exponential relation to the J value found for the O-Cu-O-Gd dihedral angle parameter is the most credible correlation.

  6. Computational electromagnetic methods for transcranial magnetic stimulation

    Science.gov (United States)

    Gomez, Luis J.

    Transcranial magnetic stimulation (TMS) is a noninvasive technique used both as a research tool for cognitive neuroscience and as a FDA approved treatment for depression. During TMS, coils positioned near the scalp generate electric fields and activate targeted brain regions. In this thesis, several computational electromagnetics methods that improve the analysis, design, and uncertainty quantification of TMS systems were developed. Analysis: A new fast direct technique for solving the large and sparse linear system of equations (LSEs) arising from the finite difference (FD) discretization of Maxwell's quasi-static equations was developed. Following a factorization step, the solver permits computation of TMS fields inside realistic brain models in seconds, allowing for patient-specific real-time usage during TMS. The solver is an alternative to iterative methods for solving FD LSEs, often requiring run-times of minutes. A new integral equation (IE) method for analyzing TMS fields was developed. The human head is highly-heterogeneous and characterized by high-relative permittivities (107). IE techniques for analyzing electromagnetic interactions with such media suffer from high-contrast and low-frequency breakdowns. The novel high-permittivity and low-frequency stable internally combined volume-surface IE method developed. The method not only applies to the analysis of high-permittivity objects, but it is also the first IE tool that is stable when analyzing highly-inhomogeneous negative permittivity plasmas. Design: TMS applications call for electric fields to be sharply focused on regions that lie deep inside the brain. Unfortunately, fields generated by present-day Figure-8 coils stimulate relatively large regions near the brain surface. An optimization method for designing single feed TMS coil-arrays capable of producing more localized and deeper stimulation was developed. Results show that the coil-arrays stimulate 2.4 cm into the head while stimulating 3

  7. Magnetic Method to Characterize the Current Densities in Breaker Arc

    International Nuclear Information System (INIS)

    Machkour, Nadia

    2005-01-01

    The purpose of this research was to use magnetic induction measurements from a low voltage breaker arc, to reconstruct the arc's current density. The measurements were made using Hall effect sensors, which were placed close to, but outside the breaking device. The arc was modelled as a rectangular current sheet, composed of a mix of threadlike current segments and with a current density varying across the propagation direction. We found the magnetic induction of the arc is a convolution product of the current density, and a function depending on the breaker geometry and arc model. Using deconvolution methods, the current density in the electric arc was determined.The method is used to study the arc behavior into the breaker device. Notably, position, arc size, and electric conductivity could all be determined, and then used to characterize the arc mode, diffuse or concentrated, and study the condition of its mode changing

  8. Magnetic resonance methods used to study the mobility of lithium ions and the formation of gamma radiolysis products in lithium silicates

    International Nuclear Information System (INIS)

    Pronin, I.S.; Nikiforov, A.S.; Vashman, A.A.

    1986-01-01

    The authors present the results of research on the mobility of lithium ions and the formation of radiation induced paramagnetic centers in the gamma radiolysis of lithium ortho- and metasilicates; nuclear magnetic resonance of Li-7 and electroparamagnetic resonance were used in the studies

  9. Synthesis of Zn{sub 0.95}Cr{sub 0.05}O DMS by co-precipitation and ceramic methods: Structural and magnetization studies

    Energy Technology Data Exchange (ETDEWEB)

    Paul Joseph, D. [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600025 (India); Naveenkumar, S. [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600025 (India); Sivakumar, N. [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600025 (India); Venkateswaran, C. [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600025 (India)]. E-mail: cvunom@hotmail.com

    2006-05-10

    Transitional metal ions-substituted ZnO are recently explored for SPINTRONICS applications. Synthesis of single-phase oxide 'diluted magnetic semiconductors' (DMS) is a must to explore the magnetic properties arising due to the strong sp-d exchange interaction. The synthesis route plays a vital role in this aspect. In this work, we have prepared Zn{sub 0.95}Cr{sub 0.05}O by using the co-precipitation method and also the standard ceramic method and optimized the conditions to obtain the single-phase compound. X-ray diffraction measurements were done on Zn{sub 0.95}Cr{sub 0.05}O annealed and sintered at various temperatures. Comparing these results, we conclude that the co-precipitation method is more convenient for obtaining single-phase compound by the relatively low temperature processing of the precipitated hydroxides. Pelleted sample examined for its magnetic property using a vibrating sample magnetometer (VSM) indicated ferromagnetic-like behavior at 300 K and a spin-glass state at 77 K.

  10. HTS Insert Magnet Design Study

    CERN Document Server

    Devaux, M; Fleiter, J; Fazilleau, P; Lécrevisse, T; Pes, C; Rey, J-M; Rifflet, J-M; Sorbi, M; Stenvall, A; Tixador, P; Volpini, G

    2011-01-01

    Future accelerator magnets will need to reach higher field in the range of 20 T. This field level is very difficult to reach using only Low Temperature Superconductor materials whereas High Temperature Superconductors (HTS) provide interesting opportunities. High current densities and stress levels are needed to design such magnets. YBCO superconductor indeed carries large current densities under high magnetic field and provides good mechanical properties especially when produced using the IBAD approach. The HFM EUCARD program studies the design and the realization of an HTS insert of 6 T inside a Nb$_{3}$Sn dipole of 13T at 4.2 K. In the2HTS insert, engineering current densities higher than 250 MA/m under 19 T are required to fulfill the specifications. The stress level is also very severe. YBCO IBAD tapes theoretically meet these challenges from presented measurements. The insert protection is also a critical because HTS materials show low quench propagation velocities and the coupling with the Nb$_{3}$Sn m...

  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. Preliminary study on magnetic tracking-based planar shape sensing and navigation for flexible surgical robots in transoral surgery: methods and phantom experiments.

    Science.gov (United States)

    Song, Shuang; Zhang, Changchun; Liu, Li; Meng, Max Q-H

    2018-02-01

    Flexible surgical robot can work in confined and complex environments, which makes it a good option for minimally invasive surgery. In order to utilize flexible manipulators in complicated and constrained surgical environments, it is of great significance to monitor the position and shape of the curvilinear manipulator in real time during the procedures. In this paper, we propose a magnetic tracking-based planar shape sensing and navigation system for flexible surgical robots in the transoral surgery. The system can provide the real-time tip position and shape information of the robot during the operation. We use wire-driven flexible robot to serve as the manipulator. It has three degrees of freedom. A permanent magnet is mounted at the distal end of the robot. Its magnetic field can be sensed with a magnetic sensor array. Therefore, position and orientation of the tip can be estimated utilizing a tracking method. A shape sensing algorithm is then carried out to estimate the real-time shape based on the tip pose. With the tip pose and shape display in the 3D reconstructed CT model, navigation can be achieved. Using the proposed system, we carried out planar navigation experiments on a skull phantom to touch three different target positions under the navigation of the skull display interface. During the experiments, the real-time shape has been well monitored and distance errors between the robot tip and the targets in the skull have been recorded. The mean navigation error is [Formula: see text] mm, while the maximum error is 3.2 mm. The proposed method provides the advantages that no sensors are needed to mount on the robot and no line-of-sight problem. Experimental results verified the feasibility of the proposed method.

  13. An experimental magnetic moment determination method based on spatial harmonic analysis of magnetic flux density signatures

    Directory of Open Access Journals (Sweden)

    A.V. Getman

    2013-12-01

    Full Text Available Theoretical aspects of an experimental determination method for residual and inductive magnetic moments of a technical object are considered. As input data, the technical object magnetic induction signatures obtained under its linear movement near a pair of three-component sensors are used. A magnetic signature integration technique based on spatial harmonic analysis of the magnetic field represented by twenty-four multipole coefficients is introduced.

  14. 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

  15. Improvement of vector compensation method for vehicle magnetic distortion field

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Hongfeng, E-mail: panghongfeng@126.com; Zhang, Qi; Li, Ji; Luo, Shitu; Chen, Dixiang; Pan, Mengchun; Luo, Feilu

    2014-03-15

    Magnetic distortions such as eddy-current field and low frequency magnetic field have not been considered in vector compensation methods. A new compensation method is proposed to suppress these magnetic distortions and improve compensation performance, in which the magnetic distortions related to measurement vectors and time are considered. The experimental system mainly consists of a three-axis fluxgate magnetometer (DM-050), an underwater vehicle and a proton magnetometer, in which the scalar value of magnetic field is obtained with the proton magnetometer and considered to be the true value. Comparing with traditional compensation methods, experimental results show that the magnetic distortions can be further reduced by two times. After compensation, error intensity and RMS error are reduced from 11684.013 nT and 7794.604 nT to 16.219 nT and 5.907 nT respectively. It suggests an effective way to improve the compensation performance of magnetic distortions. - Highlights: • A new vector compensation method is proposed for vehicle magnetic distortion. • The proposed model not only includes magnetometer error but also considers magnetic distortion. • Compensation parameters are computed directly by solving nonlinear equations. • Compared with traditional methods, the proposed method is not related with rotation angle rate. • Error intensity and RMS error can be reduced to 1/2 of the error with traditional methods.

  16. Improvement of vector compensation method for vehicle magnetic distortion field

    International Nuclear Information System (INIS)

    Pang, Hongfeng; Zhang, Qi; Li, Ji; Luo, Shitu; Chen, Dixiang; Pan, Mengchun; Luo, Feilu

    2014-01-01

    Magnetic distortions such as eddy-current field and low frequency magnetic field have not been considered in vector compensation methods. A new compensation method is proposed to suppress these magnetic distortions and improve compensation performance, in which the magnetic distortions related to measurement vectors and time are considered. The experimental system mainly consists of a three-axis fluxgate magnetometer (DM-050), an underwater vehicle and a proton magnetometer, in which the scalar value of magnetic field is obtained with the proton magnetometer and considered to be the true value. Comparing with traditional compensation methods, experimental results show that the magnetic distortions can be further reduced by two times. After compensation, error intensity and RMS error are reduced from 11684.013 nT and 7794.604 nT to 16.219 nT and 5.907 nT respectively. It suggests an effective way to improve the compensation performance of magnetic distortions. - Highlights: • A new vector compensation method is proposed for vehicle magnetic distortion. • The proposed model not only includes magnetometer error but also considers magnetic distortion. • Compensation parameters are computed directly by solving nonlinear equations. • Compared with traditional methods, the proposed method is not related with rotation angle rate. • Error intensity and RMS error can be reduced to 1/2 of the error with traditional methods

  17. SMARTer for magnetic structure studies

    Indian Academy of Sciences (India)

    Small angle neutron scattering; magnetic structure; Cu(NiFe); CuCo; ... micromagnetism, magnetic clusters embedded in a solid nonmagnetic matrix, mag- .... project. E G R Putra acknowledges the support from IAEA through the ISNS2008.

  18. Method for regenerating magnetic polyamine-epichlorohydrin resin

    Science.gov (United States)

    Kochen, Robert L.; Navratil, James D.

    1997-07-29

    Magnetic polymer resins capable of efficient removal of actinides and heavy metals from contaminated water are disclosed together with methods for making, using, and regenerating them. The resins comprise polyamine-epichlorohydrin resin beads with ferrites attached to the surfaces of the beads. Markedly improved water decontamination is demonstrated using these magnetic polymer resins of the invention in the presence of a magnetic field, as compared with water decontamination methods employing ordinary ion exchange resins or ferrites taken separately.

  19. Magnetic field transfer device and method

    Science.gov (United States)

    Wipf, S.L.

    1990-02-13

    A magnetic field transfer device includes a pair of oppositely wound inner coils which each include at least one winding around an inner coil axis, and an outer coil which includes at least one winding around an outer coil axis. The windings may be formed of superconductors. The axes of the two inner coils are parallel and laterally spaced from each other so that the inner coils are positioned in side-by-side relation. The outer coil is outwardly positioned from the inner coils and rotatable relative to the inner coils about a rotational axis substantially perpendicular to the inner coil axes to generate a hypothetical surface which substantially encloses the inner coils. The outer coil rotates relative to the inner coils between a first position in which the outer coil axis is substantially parallel to the inner coil axes and the outer coil augments the magnetic field formed in one of the inner coils, and a second position 180[degree] from the first position, in which the augmented magnetic field is transferred into the other inner coil and reoriented 180[degree] from the original magnetic field. The magnetic field transfer device allows a magnetic field to be transferred between volumes with negligible work being required to rotate the outer coil with respect to the inner coils. 16 figs.

  20. 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)

  1. Accurate and simple method for quantification of hepatic fat content using magnetic resonance imaging: a prospective study in biopsy-proven nonalcoholic fatty liver disease.

    Science.gov (United States)

    Hatta, Tomoko; Fujinaga, Yasunari; Kadoya, Masumi; Ueda, Hitoshi; Murayama, Hiroaki; Kurozumi, Masahiro; Ueda, Kazuhiko; Komatsu, Michiharu; Nagaya, Tadanobu; Joshita, Satoru; Kodama, Ryo; Tanaka, Eiji; Uehara, Tsuyoshi; Sano, Kenji; Tanaka, Naoki

    2010-12-01

    To assess the degree of hepatic fat content, simple and noninvasive methods with high objectivity and reproducibility are required. Magnetic resonance imaging (MRI) is one such candidate, although its accuracy remains unclear. We aimed to validate an MRI method for quantifying hepatic fat content by calibrating MRI reading with a phantom and comparing MRI measurements in human subjects with estimates of liver fat content in liver biopsy specimens. The MRI method was performed by a combination of MRI calibration using a phantom and double-echo chemical shift gradient-echo sequence (double-echo fast low-angle shot sequence) that has been widely used on a 1.5-T scanner. Liver fat content in patients with nonalcoholic fatty liver disease (NAFLD, n = 26) was derived from a calibration curve generated by scanning the phantom. Liver fat was also estimated by optical image analysis. The correlation between the MRI measurements and liver histology findings was examined prospectively. Magnetic resonance imaging measurements showed a strong correlation with liver fat content estimated from the results of light microscopic examination (correlation coefficient 0.91, P hepatic steatosis. Moreover, the severity of lobular inflammation or fibrosis did not influence the MRI measurements. This MRI method is simple and noninvasive, has excellent ability to quantify hepatic fat content even in NAFLD patients with mild steatosis or advanced fibrosis, and can be performed easily without special devices.

  2. Evaluation of magnetic flux distribution from magnetic domains in [Co/Pd] nanowires by magnetic domain scope method using contact-scanning of tunneling magnetoresistive sensor

    Energy Technology Data Exchange (ETDEWEB)

    Okuda, Mitsunobu, E-mail: okuda.m-ky@nhk.or.jp; Miyamoto, Yasuyoshi; Miyashita, Eiichi; Hayashi, Naoto [NHK Science and Technology Research Laboratories, 1-10-11 Kinuta Setagaya, Tokyo 157-8510 (Japan)

    2014-05-07

    Current-driven magnetic domain wall motions in magnetic nanowires have attracted great interests for physical studies and engineering applications. The magnetic force microscope (MFM) is widely used for indirect verification of domain locations in nanowires, where relative magnetic force between the local domains and the MFM probe is used for detection. However, there is an occasional problem that the magnetic moments of MFM probe influenced and/or rotated the magnetic states in the low-moment nanowires. To solve this issue, the “magnetic domain scope for wide area with nano-order resolution (nano-MDS)” method has been proposed recently that could detect the magnetic flux distribution from the specimen directly by scanning of tunneling magnetoresistive field sensor. In this study, magnetic domain structure in nanowires was investigated by both MFM and nano-MDS, and the leakage magnetic flux density from the nanowires was measured quantitatively by nano-MDS. Specimen nanowires consisted from [Co (0.3)/Pd (1.2)]{sub 21}/Ru(3) films (units in nm) with perpendicular magnetic anisotropy were fabricated onto Si substrates by dual ion beam sputtering and e-beam lithography. The length and the width of the fabricated nanowires are 20 μm and 150 nm. We have succeeded to obtain not only the remanent domain images with the detection of up and down magnetizations as similar as those by MFM but also magnetic flux density distribution from nanowires directly by nano-MDS. The obtained value of maximum leakage magnetic flux by nano-MDS is in good agreement with that of coercivity by magneto-optical Kerr effect microscopy. By changing the protective diamond-like-carbon film thickness on tunneling magnetoresistive sensor, the three-dimensional spatial distribution of leakage magnetic flux could be evaluated.

  3. A historical review on ''magnetic focusing method'' in Japan

    International Nuclear Information System (INIS)

    Yamada, Y.; Tanaka, K.; Abe, Z.

    1986-01-01

    Several topics on the development of the magnetic focusing method and its recent progress are discussed. The magnetic focusing method will be effective for measuring the local NMR parameters, and the advanced imaging technique will also be as useful as the recent conventional NMR Imaging techniques

  4. Convergence analysis of spectral element method for magnetic devices

    NARCIS (Netherlands)

    Curti, M.; Jansen, J.W.; Lomonova, E.A.

    2018-01-01

    This paper concerns the comparison of the performance of the Spectral Element Method (SEM) and the Finite Element Method (FEM) for modeling a magnetostatic problem. The convergence of the vector magnetic potential, the magnetic flux density, and the total stored energy in the system is compared with

  5. An Adaptive Orientation Estimation Method for Magnetic and Inertial Sensors in the Presence of Magnetic Disturbances

    Directory of Open Access Journals (Sweden)

    Bingfei Fan

    2017-05-01

    Full Text Available Magnetic and inertial sensors have been widely used to estimate the orientation of human segments due to their low cost, compact size and light weight. However, the accuracy of the estimated orientation is easily affected by external factors, especially when the sensor is used in an environment with magnetic disturbances. In this paper, we propose an adaptive method to improve the accuracy of orientation estimations in the presence of magnetic disturbances. The method is based on existing gradient descent algorithms, and it is performed prior to sensor fusion algorithms. The proposed method includes stationary state detection and magnetic disturbance severity determination. The stationary state detection makes this method immune to magnetic disturbances in stationary state, while the magnetic disturbance severity determination helps to determine the credibility of magnetometer data under dynamic conditions, so as to mitigate the negative effect of the magnetic disturbances. The proposed method was validated through experiments performed on a customized three-axis instrumented gimbal with known orientations. The error of the proposed method and the original gradient descent algorithms were calculated and compared. Experimental results demonstrate that in stationary state, the proposed method is completely immune to magnetic disturbances, and in dynamic conditions, the error caused by magnetic disturbance is reduced by 51.2% compared with original MIMU gradient descent algorithm.

  6. Structural, optical and magnetic studies of CuFe2O4, MgFe2O4 and ZnFe2O4 nanoparticles prepared by hydrothermal/solvothermal method

    Science.gov (United States)

    Kurian, Jessyamma; Mathew, M. Jacob

    2018-04-01

    In this paper we report the structural, optical and magnetic studies of three spinel ferrites namely CuFe2O4, MgFe2O4 and ZnFe2O4 prepared in an autoclave under the same physical conditions but with two different liquid medium and different surfactant. We use water as the medium and trisodium citrate as the surfactant for one method (Hydrothermal method) and ethylene glycol as the medium and poly ethylene glycol as the surfactant for the second method (solvothermal method). The phase identification and structural characterization are done using XRD and morphological studies are carried out by TEM. Cubical and porous spherical morphologies are obtained for hydrothermal and solvothermal process respectively without any impurity phase. The optical studies are carried out using FTIR and UV-Vis reflectance spectra. In order to elucidate the nonlinear optical behaviour of the prepared nanomaterial, open aperture z-scan technique is used. From the fitted z-scan curves nonlinear absorption coefficient and the saturation intensity are determined. The magnetic characterization of the samples is performed at room temperature using vibrating sample magnetometer measurements. The M-H curves obtained are fitted using theoretical equation and the different components of magnetization are determined. Nanoparticles with high saturation magnetization are obtained for MgFe2O4 and ZnFe2O4 prepared under solvothermal reaction. The magnetic hyperfine parameters and the cation distribution of the prepared materials are determined using room temperature Mössbauer spectroscopy. The fitted spectra reveal the difference in the magnetic hyperfine parameters owing to the change in size and morphology.

  7. System and method of operating toroidal magnetic confinement devices

    Science.gov (United States)

    Chance, M.S.; Jardin, S.C.; Stix, T.H.; Grimm, R.C.; Manickam, J.; Okabayashi, M.

    1984-08-30

    This invention pertains to methods and arrangements for attaining high beta values in plasma confinement devices. More specifically, this invention pertains to methods for accessing the second stability region of operation in toroidal magnetic confinement devices.

  8. Low field orientation magnetic separation methods for magnetotactic bacteria

    International Nuclear Information System (INIS)

    Moeschler, F.D.

    1999-01-01

    Microbial biomineralisation of iron often results in a biomass that is magnetic and can be separated from water systems by the application of a magnetic field. Magnetotactic bacteria form magnetic membrane bound crystals within their structure, generally of magnetite. In nature, this enables magnetotactic bacteria to orientate themselves with respect to the local geomagnetic field. The bacteria then migrate with flagellar driven motion towards their preferred environment. This property has been harnessed to produce a process in which metal loaded magnetotactic bacteria can be recovered from a waste stream. This process is known as orientation magnetic separation. Several methods exist which permit the unique magnetic properties of individual magnetotactic bacteria to be studied, such as U-turn analysis, transmission electron microscopy and single wire cell studies. In this work an extension of U-turn analysis was developed. The bacteria were rendered non-motile by the addition of specific metal ions and the resulting 'flip time' which occurs during a field reversal enabled the magnetic moment of individual bacteria to be determined. This method proved to be much faster and more accurate than previous methods. For a successful process to be developed, large scale culturing of magnetotactic bacteria is required Experiments showed that culture vessel geometry was an important factor for high-density growth. Despite intensive studies reproducible culturing at volumes exceeding one litre was not achieved. This work showed that numerous metal ions rendered magnetotactic bacteria non-motile at concentrations below 10 ppm. Sequential adaptation raised typical levels to in excess of 100 ppm for a number of ions. such as zinc and tin. However, specific ions. such as copper or nickel, remained motility inhibiting at lower concentrations. To achieve separation using orientation magnetic separation, motile, field susceptible MTB are required. Despite successful adaptation, the

  9. Dual phase magnetic material component and method of forming

    Science.gov (United States)

    Dial, Laura Cerully; DiDomizio, Richard; Johnson, Francis

    2017-04-25

    A magnetic component having intermixed first and second regions, and a method of preparing that magnetic component are disclosed. The first region includes a magnetic phase and the second region includes a non-magnetic phase. The method includes mechanically masking pre-selected sections of a surface portion of the component by using a nitrogen stop-off material and heat-treating the component in a nitrogen-rich atmosphere at a temperature greater than about 900.degree. C. Both the first and second regions are substantially free of carbon, or contain only limited amounts of carbon; and the second region includes greater than about 0.1 weight % of nitrogen.

  10. Methods to reduce AC losses in HTS coated conductors with magnetic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, O. [Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)], E-mail: osami-t@ynu.ac.jp; Sekizawa, S.; Alamgir, A.K.M. [Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan); Miyagi, D. [Okayama University, 1-1, Tsushima-Naka, 1-Chome, Okayama 700-8530 (Japan)

    2007-10-01

    HTS coated conductors (CCs) have high potentials as low-cost and long length conductors. However, a question remains as to what influence the magnetic property of the substrates has on the AC losses. In this paper, the influence of magnetic property of substrates on the AC losses in HTS CCs is studied. Based on the study methods to reduce the AC transport current losses and magnetization losses in CCs with magnetic substrates are investigated. It is shown that the losses can be reduced to the same level of those in CCs with non-magnetic substrates.

  11. Methods to reduce AC losses in HTS coated conductors with magnetic substrates

    International Nuclear Information System (INIS)

    Tsukamoto, O.; Sekizawa, S.; Alamgir, A.K.M.; Miyagi, D.

    2007-01-01

    HTS coated conductors (CCs) have high potentials as low-cost and long length conductors. However, a question remains as to what influence the magnetic property of the substrates has on the AC losses. In this paper, the influence of magnetic property of substrates on the AC losses in HTS CCs is studied. Based on the study methods to reduce the AC transport current losses and magnetization losses in CCs with magnetic substrates are investigated. It is shown that the losses can be reduced to the same level of those in CCs with non-magnetic substrates

  12. Study of Y{sub 1−x}Er{sub x}FeO{sub 3} (0≤x≤1) powder synthesized by sol–gel method and their magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Man; Jiang, Guojian, E-mail: guojianjiang@sit.edu.cn; Yang, Wenqian; Duan, Li; Peng, Wei; Chen, Jiang; Wang, Xiaojian

    2016-11-01

    A series of single phase Y{sub 1−x}Er{sub x}FeO{sub 3} (0≤x≤1) orthoferrite samples were synthesized by sol-gel method and their magnetic properties were studied in detail. The prepared samples were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and differential scanning calorimetry (DSC). The obviously weak ferromagnetic property, which caused by Dzialoshinski Moriya (DM) antisymmetric exchange mechanism, was observed in YFeO{sub 3} for the magnetization jump at H=0 Oe. The magnetization of YFeO{sub 3} was evidently changed by doping Er{sup 3+}. The increase of the Er{sup 3+} content in Y{sub 1−x}Er{sub x}FeO{sub 3} greatly enhanced the paramagnetic component and gradually decreased the ferromagnetic component. - Highlights: • We synthesized a series of single phase Y{sub 1−x}Er{sub x}FeO{sub 3} orthoferrite powder by sol–gel method. • We studied magnetic properties of Y{sub 1−x}Er{sub x}FeO{sub 3} (0≤x≤1) in detail. • The magnetization of YFeO{sub 3} was evidently changed by doping Er{sup 3+}.

  13. Sedimentary basins reconnaissance using the magnetic Tilt-Depth method

    Science.gov (United States)

    Salem, A.; Williams, S.; Samson, E.; Fairhead, D.; Ravat, D.; Blakely, R.J.

    2010-01-01

    We compute the depth to the top of magnetic basement using the Tilt-Depth method from the best available magnetic anomaly grids covering the continental USA and Australia. For the USA, the Tilt-Depth estimates were compared with sediment thicknesses based on drilling data and show a correlation of 0.86 between the datasets. If random data were used then the correlation value goes to virtually zero. There is little to no lateral offset of the depth of basinal features although there is a tendency for the Tilt-Depth results to be slightly shallower than the drill depths. We also applied the Tilt-Depth method to a local-scale, relatively high-resolution aeromagnetic survey over the Olympic Peninsula of Washington State. The Tilt-Depth method successfully identified a variety of important tectonic elements known from geological mapping. Of particular interest, the Tilt-Depth method illuminated deep (3km) contacts within the non-magnetic sedimentary core of the Olympic Mountains, where magnetic anomalies are subdued and low in amplitude. For Australia, the Tilt-Depth estimates also give a good correlation with known areas of shallow basement and sedimentary basins. Our estimates of basement depth are not restricted to regional analysis but work equally well at the micro scale (basin scale) with depth estimates agreeing well with drill hole and seismic data. We focus on the eastern Officer Basin as an example of basin scale studies and find a good level of agreement between previously-derived basin models. However, our study potentially reveals depocentres not previously mapped due to the sparse distribution of well data. This example thus shows the potential additional advantage of the method in geological interpretation. The success of this study suggests that the Tilt-Depth method is useful in estimating the depth to crystalline basement when appropriate quality aeromagnetic anomaly data are used (i.e. line spacing on the order of or less than the expected depth to

  14. Magnetic stripping studies for SPL

    CERN Document Server

    Posocco, P; CERN. Geneva. BE Department

    2010-01-01

    Magnetic stripping of H- can seriously enhance the beam losses along the SPL machine. These losses depend on the beam energy, on the beam transverse distribution and on the intensity of the magnetic field. For radioprotection issues the losses must be limited to 1 W/m. In this paper we will concentrate on the stripping phenomena inside the quadrupole magnets with the aim of defining the quadrupole range for the design phase of SPL.

  15. Method to manufacture bit patterned magnetic recording media

    Science.gov (United States)

    Raeymaekers, Bart; Sinha, Dipen N

    2014-05-13

    A method to increase the storage density on magnetic recording media by physically separating the individual bits from each other with a non-magnetic medium (so-called bit patterned media). This allows the bits to be closely packed together without creating magnetic "cross-talk" between adjacent bits. In one embodiment, ferromagnetic particles are submerged in a resin solution, contained in a reservoir. The bottom of the reservoir is made of piezoelectric material.

  16. An auxiliary differential equation FDTD method for anisotropic magnetized plasmas

    International Nuclear Information System (INIS)

    Liu Shaobin; Mo Jinjun; Yuan Naichang

    2004-01-01

    An auxiliary differential equation finite-difference time-domain (ADE-FDTD) methodology for anisotropic magnetized plasmas is derived. The method is based on a difference approximation of the auxiliary differential equation. A comparison with the JEC method is included. The CPU time saving by several times and accuracy of the method are confirmed by computing the reflection and transmission through a magnetized plasma layer with the direction of propagation parallel to the direction of the biasing field

  17. Study of marine magnetic field

    Digital Repository Service at National Institute of Oceanography (India)

    Bhattacharya, G.C.

    magnetized in the direction of the Earth’s magnetic field at that time. As seafloor spreading pulls the new oceanic crust apart, stripes of approximately the same size gets carried away from the ridge on each side. The basaltic oceanic crust formed...

  18. Magnetic nanoparticles colourization by a mixing-frequency method

    International Nuclear Information System (INIS)

    Tu, Liang; Wu, Kai; Klein, Todd; Wang, Jian-Ping

    2014-01-01

    Brownian and Néel relaxation of magnetic nanoparticles (MNPs) can be characterized by a highly sensitive mixing-frequency method using a search-coil based detection system. The unique magnetic properties of MNPs have been used for biomarkers detection. In this paper, we present a theory and implement an experimental detection scheme using the mixing-frequency method to identify different MNPs simultaneously. A low-frequency sinusoidal magnetic field is applied to saturate the MNPs periodically. A high-frequency sinusoidal magnetic field is then applied to generate mixing-frequency signals that are highly specific to the magnetization of MNPs. The spectra of each MNP can be defined as the complex magnetization of the MNPs over the field frequency. The magnetic spectra of various MNPs and magnetic beads have been characterized and compared. The differences between the MNPs spectra enable us to identify the individual MNPs at the same time. A test has been done to verify the ratio of two different MNPs in mixed samples based on the proposed theory. The experimental results show that the mixing-frequency method is a promising method for MNPs colourization. (paper)

  19. Method of using triaxial magnetic fields for making particle structures

    Science.gov (United States)

    Martin, James E.; Anderson, Robert A.; Williamson, Rodney L.

    2005-01-18

    A method of producing three-dimensional particle structures with enhanced magnetic susceptibility in three dimensions by applying a triaxial energetic field to a magnetic particle suspension and subsequently stabilizing said particle structure. Combinations of direct current and alternating current fields in three dimensions produce particle gel structures, honeycomb structures, and foam-like structures.

  20. Longitudinal changes in the brain in mild cognitive impairment: a magnetic resonance imaging study using the visual rating method and tensor-based morphometry.

    Science.gov (United States)

    Tuokkola, Terhi; Koikkalainen, Juha; Parkkola, Riitta; Karrasch, Mira; Lötjönen, Jyrki; Rinne, Juha O

    2017-01-01

    Background Brain atrophy is associated with mild cognitive impairment (MCI), and by using volumetric and visual analyzing methods, it is possible to differentiate between individuals with progressive MCI (MCIp) and stable MCI (MCIs). Automated analysis methods detect degenerative changes in the brain earlier and more reliably than visual methods. Purpose To detect and evaluate structural brain changes between and within the MCIs, MCIp, and control groups during a two-year follow-up period. Material and Methods Brain magnetic resonance imaging (MRI) scans of 11 participants with MCIs, 18 participants with MCIp, and 84 controls were analyzed by the visual rating method (VRM) and tensor-based morphometry (TBM). Results At baseline, both VRM and TBM differentiated the whole MCI group (combined MCIs and MCIp) and the MCIp group from the control group, but they did not differentiate the MCIs group from the control group. At follow-up, both methods differentiated the MCIp group from the control group, but minor differences between the MCIs and control groups were only seen by TBM. Neuropsychological tests did not find differences between the MCIs and control groups at follow-up. Neither method revealed relevant signs of brain atrophy progression within or between MCI subgroups during the follow-up time. Conclusion Both methods are equally good in the evaluation of structural brain changes in MCI if the groups are sufficiently large and the disease progresses to AD. Only TBM disclosed minor atrophic changes in the MCIs group compared to controls at follow-up. The results need to be confirmed with a large patient group and longer follow-up time.

  1. Nuclear magnetic resonance studies of lens transparency

    International Nuclear Information System (INIS)

    Beaulieu, C.F.

    1989-01-01

    Transparency of normal lens cytoplasm and loss of transparency in cataract were studied by nuclear magnetic resonance (NMR) methods. Phosphorus ( 31 P) NMR spectroscopy was used to measure the 31 P constituents and pH of calf lens cortical and nuclear homogenates and intact lenses as a function of time after lens enucleation and in opacification produced by calcium. Transparency was measured with laser spectroscopy. Despite complete loss of adenosine triphosphate (ATP) within 18 hrs of enucleation, the homogenates and lenses remained 100% transparent. Additions of calcium to ATP-depleted cortical homogenates produced opacification as well as concentration-dependent changes in inorganic phosphate, sugar phosphates, glycerol phosphorylcholine and pH. 1 H relaxation measurements of lens water at 200 MHz proton Larmor frequency studied temperature-dependent phase separation of lens nuclear homogenates. Preliminary measurements of T 1 and T 2 with non-equilibrium temperature changes showed a change in the slope of the temperature dependence of T 1 and T 2 at the phase separation temperature. Subsequent studies with equilibrium temperature changes showed no effect of phase separation on T 1 or T 2 , consistent with the phase separation being a low-energy process. 1 H nuclear magnetic relaxation dispersion (NMRD) studies (measurements of the magnetic field dependence of the water proton 1/T 1 relaxation rates) were performed on (1) calf lens nuclear and cortical homogenates (2) chicken lens homogenates, (3) native and heat-denatured egg white and (4) pure proteins including bovine γ-II crystallin bovine serum albumin (BSA) and myoglobin. The NMRD profiles of all samples exhibited decreases in 1/T 1 with increasing magnetic field

  2. Non linear permanent magnets modelling with the finite element method

    International Nuclear Information System (INIS)

    Chavanne, J.; Meunier, G.; Sabonnadiere, J.C.

    1989-01-01

    In order to perform the calculation of permanent magnets with the finite element method, it is necessary to take into account the anisotropic behaviour of hard magnetic materials (Ferrites, NdFeB, SmCo5). In linear cases, the permeability of permanent magnets is a tensor. This one is fully described with the permeabilities parallel and perpendicular to the easy axis of the magnet. In non linear cases, the model uses a texture function which represents the distribution of the local easy axis of the cristallytes of the magnet. This function allows a good representation of the angular dependance of the coercitive field of the magnet. As a result, it is possible to express the magnetic induction B and the tensor as functions of the field and the texture parameter. This model has been implemented in the software FLUX3D where the tensor is used for the Newton-Raphson procedure. 3D demagnetization of a ferrite magnet by a NdFeB magnet is a suitable representative example. They analyze the results obtained for an ideally oriented ferrite magnet and a real one using a measured texture parameter

  3. Rock-Magnetic Method for Post Nuclear Detonation Diagnostics

    Science.gov (United States)

    Englert, J.; Petrosky, J.; Bailey, W.; Watts, D. R.; Tauxe, L.; Heger, A. S.

    2011-12-01

    A magnetic signature characteristic of a Nuclear Electromagnetic Pulse (NEMP) may still be detectable near the sites of atmospheric nuclear tests conducted at what is now the Nevada National Security Site. This signature is due to a secondary magnetization component of the natural remanent magnetization of material containing traces of ferromagnetic particles that have been exposed to a strong pulse of magnetic field. We apply a rock-magnetic method introduced by Verrier et al. (2002), and tested on samples exposed to artificial lightning, to samples of rock and building materials (e.g. bricks, concrete) retrieved from several above ground nuclear test sites. The results of magnetization measurements are compared to NEMP simulations and historic test measurements.

  4. Magnetic resonance spectroscopy studies in migraine

    Energy Technology Data Exchange (ETDEWEB)

    Montagna, P.; Cortelli, P.; Barbiroli, B. (Inst. of Medical Pathology, Univ. of Bologna (Italy))

    1994-06-01

    The authors describe the method of [sup 31]phosphorus magnetic resonance spectroscopy and review the results when it is applied to the study of brain and muscle energy metabolism in migraine subjects. Brain energy metabolism appears to be abnormal in all major subtypes of migraine when measured both during and between attacks. Impaired energy metabolism is also documented in skeletal muscle. It is suggested that migraine is associated with a generalized disorder of mitochondrial oxidative phosphorylation and that this may constitute a threshold for the triggering of migraine attacks. 47 refs., 10 figs., 3 tabs.

  5. NMR system and method having a permanent magnet providing a rotating magnetic field

    Science.gov (United States)

    Schlueter, Ross D [Berkeley, CA; Budinger, Thomas F [Berkeley, CA

    2009-05-19

    Disclosed herein are systems and methods for generating a rotating magnetic field. The rotating magnetic field can be used to obtain rotating-field NMR spectra, such as magic angle spinning spectra, without having to physically rotate the sample. This result allows magic angle spinning NMR to be conducted on biological samples such as live animals, including humans.

  6. Principle features of metal magnetic memory method and inspection tools as compared to known magnetic NDT methods

    International Nuclear Information System (INIS)

    Dubov, A.

    2006-01-01

    Principle features of method of metal magnetic memory (MMM) as compared to known magnetic NDT methods are considered. Among the basic features of the MMM method, that it is based on use of the own magnetic leakage field (SMLF), arising in ferromagnetic and paramagnetic products on accumulations of high-density dislocations. Magnetodislocation hysteresis underlying effect of metal magnetic memory, takes place as at manufacture of products during formation of internal stresses and at their operation under action of working loads. It is impossible to obtain an information source like a self-magnetic field at any conditions with artificial magnetization in working constructions. Such information is formed and can be obtained only in a small external field, as the Earth's magnetic field is, in loaded constructions when deformation energy is a cut above the energy of the external magnetic field. Features and uniqueness of magnetometric instruments are considered. The instruments have no world analogues. Opportunities of the MMM method for the solution of actual NDT problems are: 100% quality control of machine-building products and heterogeneity of metal structure in a line production; express quality control of welded joints in the united complex system of the factors 'structural-mechanical heterogeneity - defects of a weld - structural and technological stress concentrator'; and, early diagnostics of fatigue damages of metal at an estimation and forecasting of equipment lifetime. (author)

  7. 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)

  8. Method of constructing a superconducting magnet

    Science.gov (United States)

    Satti, John A.

    1981-01-01

    A superconducting magnet designed to produce magnetic flux densities of the order of 4 to 5 Webers per square meter is constructed by first forming a cable of a plurality of matrixed superconductor wires with each wire of the plurality insulated from each other one. The cable is shaped into a rectangular cross-section and is wound with tape in an open spiral to create cooling channels. Coils are wound in a calculated pattern in saddle shapes to produce desired fields, such as dipoles, quadrupoles, and the like. Wedges are inserted between adjacent cables as needed to maintain substantially radial placement of the long dimensions of cross sections of the cables. After winding, individual strands in each of the cables are brought out to terminals and are interconnected to place all of the strands in series and to maximize the propagation of a quench by alternating conduction from an inner layer to an outer layer and from top half to bottom half as often as possible. Individual layers are separated from others by spiraled aluminum spacers to facilitate cooling. The wound coil is wrapped with an epoxy tape that is cured by heat and then machined to an interference fit with an outer aluminum pipe which is then affixed securely to the assembled coil by heating it to make a shrink fit. In an alternate embodiment, one wire of the cable is made of copper or the like to be heated externally to propagate a quench.

  9. Active magnetic regenerator method and apparatus

    Science.gov (United States)

    DeGregoria, Anthony J.; Zimm, Carl B.; Janda, Dennis J.; Lubasz, Richard A.; Jastrab, Alexander G.; Johnson, Joseph W.; Ludeman, Evan M.

    1993-01-01

    In an active magnetic regenerator apparatus having a regenerator bed of material exhibiting the magnetocaloric effect, flow of heat transfer fluid through the bed is unbalanced, so that more fluid flows through the bed from the hot side of the bed to the cold side than from the cold side to the hot side. The excess heat transfer fluid is diverted back to the hot side of the bed. The diverted fluid may be passed through a heat exchanger to draw heat from a fluid to be cooled. The apparatus may be operated at cryogenic temperatures, and the heat transfer fluid may be helium gas and the fluid to be cooled may be hydrogen gas, which is liquified by the device. The apparatus can be formed in multiple stages to allow a greater span of cooling temperatures than a single stage, and each stage may be comprised of two bed parts. Where two bed parts are employed in each stage, a portion of the fluid passing from the hot side to the cold side of a first bed part which does not have a magnetic field applied thereto is diverted back to the cold side of the other bed part in the stage, where it is passed through to the hot side. The remainder of the fluid from the cold side of the bed part of the first stage is passed to the hot side of the bed part of the second stage.

  10. Ion-optical studies for a range adaptation method in ion beam therapy using a static wedge degrader combined with magnetic beam deflection

    International Nuclear Information System (INIS)

    Chaudhri, Naved; Saito, Nami; Bert, Christoph; Franczak, Bernhard; Steidl, Peter; Durante, Marco; Schardt, Dieter; Rietzel, Eike

    2010-01-01

    Fast radiological range adaptation of the ion beam is essential when target motion is mitigated by beam tracking using scanned ion beams for dose delivery. Electromagnetically controlled deflection of a well-focused ion beam on a small static wedge degrader positioned between two dipole magnets, inside the beam delivery system, has been considered as a fast range adaptation method. The principle of the range adaptation method was tested in experiments and Monte Carlo simulations for the therapy beam line at the GSI Helmholtz Centre for Heavy Ions Research. Based on the simulations, ion optical settings of beam deflection and realignment of the adapted beam were experimentally applied to the beam line, and additional tuning was manually performed. Different degrader shapes were employed for the energy adaptation. Measured and simulated beam profiles, i.e. lateral distribution and range in water at isocentre, were analysed and compared with the therapy beam values for beam scanning. Deflected beam positions of up to ±28 mm on degrader were performed which resulted in a range adaptation of up to ±15 mm water equivalence (WE). The maximum deviation between the measured adapted range from the nominal range adaptation was below 0.4 mm WE. In experiments, the width of the adapted beam at the isocentre was adjustable between 5 and 11 mm full width at half maximum. The results demonstrate the feasibility/proof of the proposed range adaptation method for beam tracking from the beam quality point of view.

  11. Method of plasma impurity control without magnetic divertor

    International Nuclear Information System (INIS)

    Schivell, J.F.

    1977-06-01

    A method is proposed for controlling impurity generation in a tokomak by skimming and pumping the scrape-off. This method avoids many of the complications of a magnetic divertor, such as specially configured magnetic fields, toroidal symmetry, and inefficient use of toroidal field volume. Estimates are given for operating parameters. Impurity reductions of as much as a factor of 10 should be achievable. The necessary high-capacity pump would employ either titanium gettering or cryocondensation

  12. Short-wavelength magnetic recording new methods and analyses

    CERN Document Server

    Ruigrok, JJM

    2013-01-01

    Short-wavelength magnetic recording presents a series of practical solutions to a wide range of problems in the field of magnetic recording. It features many new and original results, all derived from fundamental principles as a result of up-to-date research.A special section is devoted to the playback process, including the calculations of head efficiency and head impedance, derived from new theorems.Features include:A simple and fast method for measuring efficiency; a simple method for the accurate separation of the read and write behaviour of magnetic heads; a new concept - the bandpass hea

  13. Magnetic resonance study of maghemite-based magnetic fluid

    International Nuclear Information System (INIS)

    Figueiredo, L.C.; Lacava, B.M.; Skeff Neto, K.; Pelegrini, F.; Morais, P.C.

    2008-01-01

    This study reports on the magnetic resonance (MR) data (X-band experiment) of 10.2 nm average diameter maghemite nanoparticle in the temperature range of 100-230 K. Maghemite nanoparticles were suspended as low-pH ionic magnetic fluid containing 2.3x10 17 particles/cm 3 . The temperature dependence of both resonance linewidth and resonance field of the zero-field-cooled sample as well as the resonance field of the field-cooled sample (angular variation experiment) was analyzed using well-established methodology. Information regarding particle size, particle clusterization and surface magnetic anisotropy were obtained from the analysis of the MR data. The number of magnetic sites per particle from the MR data is in excellent agreement with the number provided by the transmission electron microscopy (TEM) data. The demagnetizing field value obtained from the MR data indicates cluster of particles containing on average 1.42 particles. The MR angular variation data suggest that magnetoelastic effect accounts for the non-linearity observed for the surface component of the magnetic anisotropy

  14. An Equivalent Source Method for Modelling the Lithospheric Magnetic Field Using Satellite and Airborne Magnetic Data

    DEFF Research Database (Denmark)

    Kother, Livia Kathleen; Hammer, Magnus Danel; Finlay, Chris

    . Advantages of the equivalent source method include its local nature and the ease of transforming to spherical harmonics when needed. The method can also be applied in local, high resolution, investigations of the lithospheric magnetic field, for example where suitable aeromagnetic data is available......We present a technique for modelling the lithospheric magnetic field based on estimation of equivalent potential field sources. As a first demonstration we present an application to magnetic field measurements made by the CHAMP satellite during the period 2009-2010. Three component vector field...... for the remaining lithospheric magnetic field consists of magnetic point sources (monopoles) arranged in an icosahedron grid with an increasing grid resolution towards the airborne survey area. The corresponding source values are estimated using an iteratively reweighted least squares algorithm that includes model...

  15. Enhanced Methods to Estimate the Efficiency of Magnetic Nanoparticles in Imaging

    Directory of Open Access Journals (Sweden)

    Ann M. Hirt

    2017-12-01

    Full Text Available Magnetic resonance imaging (MRI and magnetic particle imaging (MPI are powerful methods in the early diagnosis of diseases. Both imaging techniques utilize magnetic nanoparticles that have high magnetic susceptibility, strong saturation magnetization, and no coercivity. FeraSpinTM R and its fractionated products have been studied for their imaging performances; however, a detailed magnetic characterization in their immobilized state is still lacking. This is particularly important for applications in MPI that require fixation of magnetic nanoparticles with the target cells or tissues. We examine the magnetic properties of immobilized FeraSpinTM R, its size fractions, and Resovist®, and use the findings to demonstrate which magnetic properties best predict performance. All samples show some degree of oxidation to hematite, and magnetic interaction between the particles, which impact negatively on image performance of the materials. MRI and MPI performance show a linear dependency on the slope of the magnetization curve, i.e., initial susceptibility, and average blocking temperature. The best performance of particles in immobilized state for MPI is found for particle sizes close to the boundary between superparamagnetic (SP and magnetically ordered, in which only Néel relaxation is important. Initial susceptibility and bifurcation temperature are the best indicators to predict MRI and MPI performance.

  16. Method for using magnetic particles in droplet microfluidics

    Science.gov (United States)

    Shah, Gaurav Jitendra (Inventor); Kim, Chang-Jin (Inventor)

    2012-01-01

    Methods of utilizing magnetic particles or beads (MBs) in droplet-based (or digital) microfluidics are disclosed. The methods may be used in enrichment or separation processes. A first method employs the droplet meniscus to assist in the magnetic collection and positioning of MBs during droplet microfluidic operations. The sweeping movement of the meniscus lifts the MBs off the solid surface and frees them from various surface forces acting on the MBs. A second method uses chemical additives to reduce the adhesion of MBs to surfaces. Both methods allow the MBs on a solid surface to be effectively moved by magnetic force. Droplets may be driven by various methods or techniques including, for example, electrowetting, electrostatic, electromechanical, electrophoretic, dielectrophoretic, electroosmotic, thermocapillary, surface acoustic, and pressure.

  17. Advanced quantitative magnetic nondestructive evaluation methods - Theory and experiment

    Science.gov (United States)

    Barton, J. R.; Kusenberger, F. N.; Beissner, R. E.; Matzkanin, G. A.

    1979-01-01

    The paper reviews the scale of fatigue crack phenomena in relation to the size detection capabilities of nondestructive evaluation methods. An assessment of several features of fatigue in relation to the inspection of ball and roller bearings suggested the use of magnetic methods; magnetic domain phenomena including the interaction of domains and inclusions, and the influence of stress and magnetic field on domains are discussed. Experimental results indicate that simplified calculations can be used to predict many features of these results; the data predicted by analytic models which use finite element computer analysis predictions do not agree with respect to certain features. Experimental analyses obtained on rod-type fatigue specimens which show experimental magnetic measurements in relation to the crack opening displacement and volume and crack depth should provide methods for improved crack characterization in relation to fracture mechanics and life prediction.

  18. MFM study of magnetic interaction between recording and soft magnetic layers

    International Nuclear Information System (INIS)

    Honda, Yukio; Tanahashi, Kiwamu; Hirayama, Yoshiyuki; Kikukawa, Atsushi; Futamoto, Masaaki

    2001-01-01

    Magnetic force microscopy was used to study the magnetic interaction between the recording and the soft magnetic layers in double-layer perpendicular media by observing the magnetization structure from the soft magnetic layer side. There was a strong magnetic interaction between the recording and the soft magnetic layers. Introducing a thin nonmagnetic intermediate layer between the two layers greatly reduced the magnetic interaction and drastically reduced the medium noise

  19. MHD simulation study of compact toroid injection into magnetized plasmas

    International Nuclear Information System (INIS)

    Suzuki, Yoshio; Kishimoto, Yasuaki

    2000-01-01

    To understand the fuelling process in a fusion device by a compact toroid (CT) plasmoid injection method, we have carried out MHD numerical simulations where a spheromak-like CT (SCT) is injected into a magnetized target plasma region. So far, we revealed that the penetration depth of the SCT plasma becomes shorter than that estimated from the conducting sphere (CS) model, because in the simulation the Lorentz force of the target magnetic field sequentially decelerates the injected SCT while in the CS model only the magnetic pressure force acts as the deceleration mechanism. In this study, we represent the new theoretical model where the injected SCT is decelerated by both the magnetic pressure force and the magnetic tension force (we call it the non-slipping sphere (NS) model) and investigate in detail the deceleration mechanism of the SCT by comparison with simulation results. As a result, it is found that the decrease of the SCT kinetic energy in the simulation coincides with that in the NS model more than in the CS model. It means that not only the magnetic pressure force but also the magnetic tension force acts as the deceleration mechanism of the SCT. Furthermore, it is revealed that magnetic reconnection between the SCT magnetic field and the target magnetic field plays a role to relax the SCT deceleration. (author)

  20. Hybrid-secondary uncluttered permanent magnet machine and method

    Science.gov (United States)

    Hsu, John S.

    2005-12-20

    An electric machine (40) has a stator (43), a permanent magnet rotor (38) with permanent magnets (39) and a magnetic coupling uncluttered rotor (46) for inducing a slip energy current in secondary coils (47). A dc flux can be produced in the uncluttered rotor when the secondary coils are fed with dc currents. The magnetic coupling uncluttered rotor (46) has magnetic brushes (A, B, C, D) which couple flux in through the rotor (46) to the secondary coils (47c, 47d) without inducing a current in the rotor (46) and without coupling a stator rotational energy component to the secondary coils (47c, 47d). The machine can be operated as a motor or a generator in multi-phase or single-phase embodiments and is applicable to the hybrid electric vehicle. A method of providing a slip energy controller is also disclosed.

  1. Method and apparatus for assembling permanent magnet rotors

    Science.gov (United States)

    Hsu, J.S.; Adams, D.J.

    1999-06-22

    A permanent magnet assembly for assembly in large permanent magnet motors and generators includes a two-piece carrier that can be slid into a slot in the rotor and then secured in place using a set screw. The invention also provides an auxiliary carrier device with guide rails that line up with the teeth of the rotor, so that a permanent magnet assembly can be pushed first into a slot, and then down the slot to its proper location. An auxiliary tool is provided to move the permanent magnet assembly into position in the slot before it is secured in place. Methods of assembling and disassembling the magnet assemblies in the rotor are also disclosed. 2 figs.

  2. Fusion magnet safety studies program: superconducting magnet protection system and failure. Interim report

    International Nuclear Information System (INIS)

    Allinger, J.; Danby, G.; Hsieh, S.Y.; Keane, J.; Powell, J.; Prodell, A.

    1975-11-01

    This report includes the first two quarters study of available information on schemes for protecting superconducting magnets. These schemes can be divided into two different categories. The first category deals with the detection of faulty regions (or normal regions) in the magnet. The second category relates to the protection of the magnet when a fault is detected, and the derived signal which can be used to activate a safety system (or energy removal system). The general detection and protection methods are first described briefly and then followed by a survey of the protection systems used by different laboratories for various magnets. A survey of the cause of the magnet difficulties or failures is also included. A preliminary discussion of these protection schemes and the experimental development of this program is given

  3. Methods for characterizing magnetic footprints of perpendicular magnetic recording writer heads

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shaoping, E-mail: shaoping.li@wdc.com; Lin, Ed; George, Zach; Terrill, Dave; Mendez, H.; Santucci, J.; Yie, Derek [Western Digital Corp., 44100 Osgood Road, Fremont, California 94539 (United States)

    2014-05-07

    In this work, the magnetic footprints, along with some of its dynamic features in recording process, of perpendicular magnetic recording writer heads have been characterized by using three different techniques. Those techniques are the spin-stand stationary footprint technique, the spin-stand dynamic footprint technique, and the coherent writing technique combined with magnetic force microscope imaging method. The characteristics of those techniques have been compared to one another. It was found experimentally that the spin-stand stationary method could not precisely catch some peculiar recording dynamics of the write heads in certain conditions. The advantages and disadvantages among all those techniques are also examined and discussed in detail.

  4. Methods for characterizing magnetic footprints of perpendicular magnetic recording writer heads

    International Nuclear Information System (INIS)

    Li, Shaoping; Lin, Ed; George, Zach; Terrill, Dave; Mendez, H.; Santucci, J.; Yie, Derek

    2014-01-01

    In this work, the magnetic footprints, along with some of its dynamic features in recording process, of perpendicular magnetic recording writer heads have been characterized by using three different techniques. Those techniques are the spin-stand stationary footprint technique, the spin-stand dynamic footprint technique, and the coherent writing technique combined with magnetic force microscope imaging method. The characteristics of those techniques have been compared to one another. It was found experimentally that the spin-stand stationary method could not precisely catch some peculiar recording dynamics of the write heads in certain conditions. The advantages and disadvantages among all those techniques are also examined and discussed in detail

  5. Methods for characterizing magnetic footprints of perpendicular magnetic recording writer heads

    Science.gov (United States)

    Li, Shaoping; Lin, Ed; George, Zach; Terrill, Dave; Mendez, H.; Santucci, J.; Yie, Derek

    2014-01-01

    In this work, the magnetic footprints, along with some of its dynamic features in recording process, of perpendicular magnetic recording writer heads have been characterized by using three different techniques. Those techniques are the spin-stand stationary footprint technique, the spin-stand dynamic footprint technique, and the coherent writing technique combined with magnetic force microscope imaging method. The characteristics of those techniques have been compared to one another. It was found experimentally that the spin-stand stationary method could not precisely catch some peculiar recording dynamics of the write heads in certain conditions. The advantages and disadvantages among all those techniques are also examined and discussed in detail. PMID:24753633

  6. A review of the magnetic properties, synthesis methods and applications of maghemite

    Energy Technology Data Exchange (ETDEWEB)

    Shokrollahi, H., E-mail: shokrollahi@sutech.ac.ir

    2017-03-15

    It must be pointed out that maghemite (γ-Fe{sub 2}O{sub 3}) with a cubic spinel structure is a crucial material for various applications, including spin electronic devices, high-density magnetic recording, nano-medicines and biosensors. This paper has to do with a review study on the synthesis methods, magnetic properties and application of maghemite in the form of one-dimensional (1D) nanostructured materials, such as nanoparticles, nanotubes, nano-rods, and nanowires, as well as two-dimensional (2D) thin films. The results revealed that maghemite is widely used in the biomedical applications (hyperthermia, magnetic resonance imaging and drug delivery) and magnetic recording devices. The unmodified and Co/Mn modified maghemite thin films prepared by the dc-reactive magnetron sputtering show the excellent values of coercivity 2100 Oe and 3900 Oe, respectively, for the magnetic storage application. The super-paramagnetic particles with 7 nm size and the saturation magnetization of 80 emu/g prepared by the established thermolysis method are good candidates for bio-medical applications. - Highlights: • Among iron oxides, maghemite is one of the most important magnetic ceramics. • Maghemite is widely sued in magnetic recording and biomedicine. • This paper attempts to give an overview on the some important areas. • They contain synthetic methods, magnetic study, structural study and applications.

  7. Magnetic nanoparticles studied by small angle X-ray scattering

    International Nuclear Information System (INIS)

    Oliveira, Cristiano Luis Pinto; Antonel, Soledad; Negri, Martin

    2011-01-01

    Full text: Magnetic nanoparticles have attracted much attention in the past decades because of their potential applications in high-density magnetic recording, magnetic fluids, data storage, spin-tronics, solar cells, sensors and catalysis. Among the magnetic nanoparticles, cobalt ferrite (CoFe 2 O 4 ) has been widely studied due to high electromagnetic performance, excellent chemical stability, mechanical hardness, and high cubic magnetocrystalline anisotropy. These properties make it a promising candidate for many applications in commercial electronics such as video, audio tapes, high-density digital recording media, and magnetic fluids. Other interesting application is the use of magnetic nanocompounds in the design of magneto elastomers. Magnetoelastomers are dispersions of magnetic particles into an elastomer polymer matrix. These materials are highly promising for applications in the development of sensors and actuators, mainly because of the possibility to optimize the quality parameters of the devices by systematically changing the chemical nature of both the inorganic particles and the organic polymeric matrix, with the consequent modification of the magnetic, electric and elastic properties. Moreover, nanoparticles of cobalt-iron oxides (cobalt ferrite, CoFe 2 O 4 ) appears as very interesting compounds for magnetoelasticity, not only because present magnetic anisotropy, moderate-high magnetization and high coercitivity at room temperature, but also because the possibility to modulate its magnetic properties by chemical synthesis, that is by synthesizing nanoparticles of different sizes having thus not only different magnetic parameters but also different magnetic behavior (superparamagnetism or ferromagnetism). That means that most of the magnetic properties of CoFe 2 O 4 ferrite strongly depend on the size and shape of the nanoparticles, which are closely related to the method of preparation. On the other hand, nickel nanoparticles are very interesting

  8. Magnetic nanoparticles studied by small angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Cristiano Luis Pinto [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Grupo de Fluidos Complexos; Antonel, Soledad; Negri, Martin [Universidad de Buenos Aires (UBA) (Argentina). Facultad de Ciencias Exactas y Naturales. Dept. de Quimica Inorganica, Analitica y Quimica Fisica

    2011-07-01

    Full text: Magnetic nanoparticles have attracted much attention in the past decades because of their potential applications in high-density magnetic recording, magnetic fluids, data storage, spin-tronics, solar cells, sensors and catalysis. Among the magnetic nanoparticles, cobalt ferrite (CoFe{sub 2}O{sub 4}) has been widely studied due to high electromagnetic performance, excellent chemical stability, mechanical hardness, and high cubic magnetocrystalline anisotropy. These properties make it a promising candidate for many applications in commercial electronics such as video, audio tapes, high-density digital recording media, and magnetic fluids. Other interesting application is the use of magnetic nanocompounds in the design of magneto elastomers. Magnetoelastomers are dispersions of magnetic particles into an elastomer polymer matrix. These materials are highly promising for applications in the development of sensors and actuators, mainly because of the possibility to optimize the quality parameters of the devices by systematically changing the chemical nature of both the inorganic particles and the organic polymeric matrix, with the consequent modification of the magnetic, electric and elastic properties. Moreover, nanoparticles of cobalt-iron oxides (cobalt ferrite, CoFe{sub 2}O{sub 4}) appears as very interesting compounds for magnetoelasticity, not only because present magnetic anisotropy, moderate-high magnetization and high coercitivity at room temperature, but also because the possibility to modulate its magnetic properties by chemical synthesis, that is by synthesizing nanoparticles of different sizes having thus not only different magnetic parameters but also different magnetic behavior (superparamagnetism or ferromagnetism). That means that most of the magnetic properties of CoFe{sub 2}O{sub 4} ferrite strongly depend on the size and shape of the nanoparticles, which are closely related to the method of preparation. On the other hand, nickel

  9. a Novel Method for Improving Plasma Nitriding Efficiency: Pre-Magnetization by DC Magnetic Field

    Science.gov (United States)

    Kovaci, Halim; Yetim, Ali Fatih; Bozkurt, Yusuf Burak; Çelik, Ayhan

    2017-06-01

    In this study, a novel pre-magnetization process, which enables easy diffusion of nitrogen, was used to enhance plasma nitriding efficiency. Firstly, magnetic fields with intensities of 1500G and 2500G were applied to the untreated samples before nitriding. After the pre-magnetization, the untreated and pre-magnetized samples were plasma nitrided for 4h in a gas mixture of 50% N2-50% H2 at 500∘C and 600∘C. The structural, mechanical and morphological properties of samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness tester and surface tension meter. It was observed that pre-magnetization increased the surface energy of the samples. Therefore, both compound and diffusion layer thicknesses increased with pre-magnetization process before nitriding treatment. As modified layer thickness increased, higher surface hardness values were obtained.

  10. Interferometric methods for mapping static electric and magnetic fields

    DEFF Research Database (Denmark)

    Pozzi, Giulio; Beleggia, Marco; Kasama, Takeshi

    2014-01-01

    The mapping of static electric and magnetic fields using electron probes with a resolution and sensitivity that are sufficient to reveal nanoscale features in materials requires the use of phase-sensitive methods such as the shadow technique, coherent Foucault imaging and the Transport of Intensi......) the model-independent determination of the locations and magnitudes of field sources (electric charges and magnetic dipoles) directly from electron holographic data.......The mapping of static electric and magnetic fields using electron probes with a resolution and sensitivity that are sufficient to reveal nanoscale features in materials requires the use of phase-sensitive methods such as the shadow technique, coherent Foucault imaging and the Transport of Intensity...... on theoretical models that form the basis of the quantitative interpretation of electron holographic data. We review the application of electron holography to a variety of samples (including electric fields associated with p–n junctions in semiconductors, quantized magnetic flux in superconductors...

  11. A method of inversion of satellite magnetic anomaly data

    Science.gov (United States)

    Mayhew, M. A.

    1977-01-01

    A method of finding a first approximation to a crustal magnetization distribution from inversion of satellite magnetic anomaly data is described. Magnetization is expressed as a Fourier Series in a segment of spherical shell. Input to this procedure is an equivalent source representation of the observed anomaly field. Instability of the inversion occurs when high frequency noise is present in the input data, or when the series is carried to an excessively high wave number. Preliminary results are given for the United States and adjacent areas.

  12. Neutron-scattering studies of magnetic superconductors

    International Nuclear Information System (INIS)

    Sinha, S.K.; Crabtree, G.W.; Hinks, D.G.; Mook, H.A.; Pringle, O.A.

    1982-01-01

    Results obtained in the last few years obtained by neutron diffraction on the nature of the magnetic ordering in magnetic superconductors are reviewed. Emphasis is given to studies of the complex intermediate phase in ferromagnetic superconductors where both superconductivity and ferromagnetism appear to coexist

  13. Study of a magnetically oriented lyotropic mesophase

    International Nuclear Information System (INIS)

    Amaral, L.Q.; Pimentel, C.A.; Tavares, M.R.; Vanin, J.A.

    A study of a magnetically oriented lyomesophase formed by a quaternary system (Na decyl sulfate/water/decanol/ Na sulfate) is reported. Small angle X-ray diffraction measurements have been performed on unoriented samples and samples previously subjected to the action of magnetic fields (H vector). A model of finite planar micelles surrounded by water is proposed [pt

  14. Rotatable Small Permanent Magnet Array for Ultra-Low Field Nuclear Magnetic Resonance Instrumentation: A Concept Study.

    Science.gov (United States)

    Vogel, Michael W; Giorni, Andrea; Vegh, Viktor; Pellicer-Guridi, Ruben; Reutens, David C

    2016-01-01

    We studied the feasibility of generating the variable magnetic fields required for ultra-low field nuclear magnetic resonance relaxometry with dynamically adjustable permanent magnets. Our motivation was to substitute traditional electromagnets by distributed permanent magnets, increasing system portability. The finite element method (COMSOL®) was employed for the numerical study of a small permanent magnet array to calculate achievable magnetic field strength, homogeneity, switching time and magnetic forces. A manually operated prototype was simulated and constructed to validate the numerical approach and to verify the generated magnetic field. A concentric small permanent magnet array can be used to generate strong sample pre-polarisation and variable measurement fields for ultra-low field relaxometry via simple prescribed magnet rotations. Using the array, it is possible to achieve a pre-polarisation field strength above 100 mT and variable measurement fields ranging from 20-50 μT with 200 ppm absolute field homogeneity within a field-of-view of 5 x 5 x 5 cubic centimetres. A dynamic small permanent magnet array can generate multiple highly homogeneous magnetic fields required in ultra-low field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) instruments. This design can significantly reduce the volume and energy requirements of traditional systems based on electromagnets, improving portability considerably.

  15. Apparatus and method for nuclear magnetic resonance scanning and mapping

    International Nuclear Information System (INIS)

    Damadian, R.V.

    1983-01-01

    An improved apparatus and method is disclosed for analyzing the chemical and structural composition of a specimen including whole-body specimens which may include, for example, living mammals, utilizing nuclear magnetic resonance (NMR) techniques. A magnetic field space necessary to obtain an NMR signal characteristic of the chemical structure of the specimen is focused to provide a resonance domain of selectable size, which may then be moved in a pattern with respect to the specimen to scan the specimen

  16. METHOD FOR EXCHANGING ENERGY WITH A PLASMA BY MAGNETIC PUMPING

    Science.gov (United States)

    Hall, L.S.

    1963-12-31

    A method of heating a plasma confined by a static magnetic field is presented. A time-varying magnetic field having a rise time to a predetermined value substantially less than its fall time is applied to a portion of the plasma. Because of the much shorter rise time, the plasma is reversibly heated. This cycle is repeated until the desired plasma temperature is reached. (AEC)

  17. Classification of analysis methods for characterization of magnetic nanoparticle properties

    DEFF Research Database (Denmark)

    Posth, O.; Hansen, Mikkel Fougt; Steinhoff, U.

    2015-01-01

    The aim of this paper is to provide a roadmap for the standardization of magnetic nanoparticle (MNP) characterization. We have assessed common MNP analysis techniques under various criteria in order to define the methods that can be used as either standard techniques for magnetic particle...... characterization or those that can be used to obtain a comprehensive picture of a MNP system. This classification is the first step on the way to develop standards for nanoparticle characterization....

  18. Removal of algal blooms from freshwater by the coagulation-magnetic separation method.

    Science.gov (United States)

    Liu, Dan; Wang, Peng; Wei, Guanran; Dong, Wenbo; Hui, Franck

    2013-01-01

    This research investigated the feasibility of changing waste into useful materials for water treatment and proposed a coagulation-magnetic separation technique. This technique was rapid and highly effective for clearing up harmful algal blooms in freshwater and mitigating lake eutrophication. A magnetic coagulant was synthesized by compounding acid-modified fly ash with magnetite (Fe(3)O(4)). Its removal effects on algal cells and dissolved organics in water were studied. After mixing, coagulation, and magnetic separation, the flocs obtained from the magnet surface were examined by SEM. Treated samples were withdrawn for the content determination of chlorophyll-a, turbidity, chemical oxygen demand (COD), total nitrogen, and total phosphorus. More than 99 % of algal cells were removed within 5 min after the addition of magnetic coagulant at optimal loadings (200 mg L(-1)). The removal efficiencies of COD, total nitrogen, and phosphorus were 93, 91, and 94 %, respectively. The mechanism of algal removal explored preliminarily showed that the magnetic coagulant played multiple roles in mesoporous adsorption, netting and bridging, as well as high magnetic responsiveness to a magnetic field. The magnetic-coagulation separation method can rapidly and effectively remove algae from water bodies and greatly mitigate eutrophication of freshwater using a new magnetic coagulant. The method has good performance, is low cost, can turn waste into something valuable, and provides reference and directions for future pilot and production scale-ups.

  19. Satellite Magnetic Residuals Investigated With Geostatistical Methods

    DEFF Research Database (Denmark)

    Fox Maule, Chaterine; Mosegaard, Klaus; Olsen, Nils

    2005-01-01

    (which consists of measurement errors and unmodeled signal), and is typically assumed to be uncorrelated and Gaussian distributed. We have applied geostatistical methods to analyze the residuals of the Oersted (09d/04) field model (www.dsri.dk/Oersted/Field models/IGRF 2005 candidates/), which is based...

  20. Method for nuclear magnetic resonance imaging

    Science.gov (United States)

    Kehayias, J.J.; Joel, D.D.; Adams, W.H.; Stein, H.L.

    1988-05-26

    A method for in vivo NMR imaging of the blood vessels and organs of a patient characterized by using a dark dye-like imaging substance consisting essentially of a stable, high-purity concentration of D/sub 2/O in a solution with water.

  1. An orientation measurement method based on Hall-effect sensors for permanent magnet spherical actuators with 3D magnet array.

    Science.gov (United States)

    Yan, Liang; Zhu, Bo; Jiao, Zongxia; Chen, Chin-Yin; Chen, I-Ming

    2014-10-24

    An orientation measurement method based on Hall-effect sensors is proposed for permanent magnet (PM) spherical actuators with three-dimensional (3D) magnet array. As there is no contact between the measurement system and the rotor, this method could effectively avoid friction torque and additional inertial moment existing in conventional approaches. Curved surface fitting method based on exponential approximation is proposed to formulate the magnetic field distribution in 3D space. The comparison with conventional modeling method shows that it helps to improve the model accuracy. The Hall-effect sensors are distributed around the rotor with PM poles to detect the flux density at different points, and thus the rotor orientation can be computed from the measured results and analytical models. Experiments have been conducted on the developed research prototype of the spherical actuator to validate the accuracy of the analytical equations relating the rotor orientation and the value of magnetic flux density. The experimental results show that the proposed method can measure the rotor orientation precisely, and the measurement accuracy could be improved by the novel 3D magnet array. The study result could be used for real-time motion control of PM spherical actuators.

  2. Developments of the neutron scattering analysis method for the determination of magnetic structures

    Energy Technology Data Exchange (ETDEWEB)

    Park, Je-Geun; Chung, Jae Gwan; Park, Jung Hwan; Kong, Ung Girl [Inha Univ., Incheon (Korea); So, Ji Yong [Seoul National University, Seoul(Korea)

    2001-04-01

    Neutron diffraction is up to now almost the only and very important experimental method of determining the magnetic structure of materials. Unlike the studies of crystallographic structure, however to use neutron diffraction for magnetic structure determination is not easily accessible to non-experts because of the complexity of magnetic group theory: which is very important in the magnetic structure analysis. With the recent development of computer code for magnetic group, it is now time to rethink of these difficulties. In this work, we have used the computer code of the magnetic group (Mody-2) and Fullprof refinement program in order to study the magnetic structure of YMnO{sub 3} and other interesting materials. YMnO{sub 3} forms in the hexagonal structure and show both ferroelectric and antiferromagnetic phase transitions. Since it was recently found that YMnO{sub 3} can be used as a nonvolatile memory device, there has been many numbers of applied research on this material. We used neutron diffraction to determine the magnetic structure, and, in particular, to investigate the correlation between the order parameters of the ferroelectric and antiferromagnetic phase transitions. From this study, we have demonstrated that with a proper use of the computer code of the magnetic group one can overcome most of difficulties arising from the magnetic group theory. 4 refs., 8 figs., 5 tabs. (Author)

  3. Contribution to study and realization of 20-Tesla superconducting magnet

    International Nuclear Information System (INIS)

    Marty, J.

    1981-11-01

    This work is mainly concerned with 20 Tesla induction production study. This magnetic induction should be produced by associating a series of coils using high critical field commercial: superconductors to the 10 Tesla magnet (diameter: 300; let's call it 10-300 magnet). The operation temperature lowering from 4,2 0 K to 1,8 0 K should effectively lead to much higher inductions (with equal effective diameter) than the greatest performances nowadays realized at 4,2 0 K temperature. To this performance augmentation is associated a more important energy density augmentation. This leads to the necessity of the knowledge of the superconducting material physical properties. They are studied in this report. Following, different methodes of magnet calculations are described: problems related to mechanical constraints, protection and stability must be known. Finally, some coils of the 10-300 magnet are presented together with their realization [fr

  4. 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

  5. Comparative analysis of various methods for modelling permanent magnet machines

    NARCIS (Netherlands)

    Ramakrishnan, K.; Curti, M.; Zarko, D.; Mastinu, G.; Paulides, J.J.H.; Lomonova, E.A.

    2017-01-01

    In this paper, six different modelling methods for permanent magnet (PM) electric machines are compared in terms of their computational complexity and accuracy. The methods are based primarily on conformal mapping, mode matching, and harmonic modelling. In the case of conformal mapping, slotted air

  6. Application of magnetic printing method to hard-disk media with double recording layers

    International Nuclear Information System (INIS)

    Ono, Takuya; Kuboki, Yoshiyuki; Ajishi, Yoshifumi; Saito, Akira

    2003-01-01

    The magnetic printing method, which can duplicate soft magnetic patterns containing digital information such as servosignals formed on a master disk onto recording media, enables signals to be written to hard-disk media having high coercivities above 6000 Oe. We propose the application of the magnetic printing method to a hard-disk medium having double recording layers, one layer of which has high coercivity and is to be printed with digital information. This double recording layer medium is a hard-disk medium that has a magnetic read-only-memory (MROM) layer. In this study, we demonstrated a method for printing to this medium, which has MROM, and discussed the magnetic properties and recording performances of this medium

  7. Methods in rock magnetism and palaeomagnetism techniques and instrumentation

    CERN Document Server

    Collinson, D W

    1983-01-01

    During the last 30 years the study of the magnetic properties of rocks and minerals has substantially contributed to several fields of science. Perhaps the best known and most significant advances have resulted from the study of palaeomagnetism, which led to quantitative confirmation of continental drift and polar wandering through interpretation of the direction of remanent magnetism observed in rocks of different ages from different continents. Palaeomagnetism has also, through observations of reversals of magnetiz­ ation, ancient secular variation and ancient field intensities provided data relevant to the origin of the geomagnetic field, and other investigations have contributed significantly to large-scale and local geological studies, the dating of archaeological events and artefacts and more recently to lunar and meteoritic studies. Rock and mineral magnetism has proved to be an interesting study in its own right through the complex magnetic properties and interactions observed in the iron-titanium ox...

  8. System and method for magnetic current density imaging at ultra low magnetic fields

    Science.gov (United States)

    Espy, Michelle A.; George, John Stevens; Kraus, Robert Henry; Magnelind, Per; Matlashov, Andrei Nikolaevich; Tucker, Don; Turovets, Sergei; Volegov, Petr Lvovich

    2016-02-09

    Preferred systems can include an electrical impedance tomography apparatus electrically connectable to an object; an ultra low field magnetic resonance imaging apparatus including a plurality of field directions and disposable about the object; a controller connected to the ultra low field magnetic resonance imaging apparatus and configured to implement a sequencing of one or more ultra low magnetic fields substantially along one or more of the plurality of field directions; and a display connected to the controller, and wherein the controller is further configured to reconstruct a displayable image of an electrical current density in the object. Preferred methods, apparatuses, and computer program products are also disclosed.

  9. Magnetic agglomeration method for size control in the synthesis of magnetic nanoparticles

    Science.gov (United States)

    Huber, Dale L [Albuquerque, NM

    2011-07-05

    A method for controlling the size of chemically synthesized magnetic nanoparticles that employs magnetic interaction between particles to control particle size and does not rely on conventional kinetic control of the reaction to control particle size. The particles are caused to reversibly agglomerate and precipitate from solution; the size at which this occurs can be well controlled to provide a very narrow particle size distribution. The size of particles is controllable by the size of the surfactant employed in the process; controlling the size of the surfactant allows magnetic control of the agglomeration and precipitation processes. Agglomeration is used to effectively stop particle growth to provide a very narrow range of particle sizes.

  10. An Alternative Method for Identifying Interplanetary Magnetic Cloud Regions

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda-Gonzalez, A.; Prestes, A.; Klausner, V. [Laboratory of Physics and Astronomy, IP and D/Universidade do Vale do Paraíba—UNIVAP, São José dos Campos, SP (Brazil); Mendes, O. [Division of Space Geophysics, National Institute for Space Research, São José dos Campos, SP (Brazil); Calzadilla, A. [Department of Space Geophysics, Institute of Geophysics and Astronomy, Havana (Cuba); Domingues, M. O., E-mail: ojeda.gonzalez.a@gmail.com [Associate Laboratory of Applied Computing and Mathematics, National Institute for Space Research, São José dos Campos, SP (Brazil)

    2017-03-10

    Spatio-temporal entropy (STE) analysis is used as an alternative mathematical tool to identify possible magnetic cloud (MC) candidates. We analyze Interplanetary Magnetic Field (IMF) data using a time interval of only 10 days. We select a convenient data interval of 2500 records moving forward by 200 record steps until the end of the time series. For every data segment, the STE is calculated at each step. During an MC event, the STE reaches values close to zero. This extremely low value of STE is due to MC structure features. However, not all of the magnetic components in MCs have STE values close to zero at the same time. For this reason, we create a standardization index (the so-called Interplanetary Entropy, IE, index). This index is a worthwhile effort to develop new tools to help diagnose ICME structures. The IE was calculated using a time window of one year (1999), and it has a success rate of 70% over other identifiers of MCs. The unsuccessful cases (30%) are caused by small and weak MCs. The results show that the IE methodology identified 9 of 13 MCs, and emitted nine false alarm cases. In 1999, a total of 788 windows of 2500 values existed, meaning that the percentage of false alarms was 1.14%, which can be considered a good result. In addition, four time windows, each of 10 days, are studied, where the IE method was effective in finding MC candidates. As a novel result, two new MCs are identified in these time windows.

  11. A Power-Efficient Propulsion Method for Magnetic Microrobots

    Directory of Open Access Journals (Sweden)

    Gioia Lucarini

    2014-07-01

    Full Text Available Current magnetic systems for microrobotic navigation consist of assemblies of electromagnets, which allow for the wireless accurate steering and propulsion of sub-millimetric bodies. However, large numbers of windings and/or high currents are needed in order to generate suitable magnetic fields and gradients. This means that magnetic navigation systems are typically cumbersome and require a lot of power, thus limiting their application fields. In this paper, we propose a novel propulsion method that is able to dramatically reduce the power demand of such systems. This propulsion method was conceived for navigation systems that achieve propulsion by pulling microrobots with magnetic gradients. We compare this power-efficient propulsion method with the traditional pulling propulsion, in the case of a microrobot swimming in a micro-structured confined liquid environment. Results show that both methods are equivalent in terms of accuracy and the velocity of the motion of the microrobots, while the new approach requires only one ninth of the power needed to generate the magnetic gradients. Substantial equivalence is demonstrated also in terms of the manoeuvrability of user-controlled microrobots along a complex path.

  12. Methods for magnetic resonance analysis using magic angle technique

    Science.gov (United States)

    Hu, Jian Zhi [Richland, WA; Wind, Robert A [Kennewick, WA; Minard, Kevin R [Kennewick, WA; Majors, Paul D [Kennewick, WA

    2011-11-22

    Methods of performing a magnetic resonance analysis of a biological object are disclosed that include placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. In particular embodiments the method includes pulsing the radio frequency to provide at least two of a spatially selective read pulse, a spatially selective phase pulse, and a spatially selective storage pulse. Further disclosed methods provide pulse sequences that provide extended imaging capabilities, such as chemical shift imaging or multiple-voxel data acquisition.

  13. Method for making an improved magnetic encoding device

    Science.gov (United States)

    Fox, Richard J.

    1981-01-01

    A magnetic encoding device and method for making the same are provided for use as magnetic storage mediums in identification control applications which give output signals from a reader that are of shorter duration and substantially greater magnitude than those of the prior art. Magnetic encoding elements are produced by uniformly bending wire or strip stock of a magnetic material longitudinally about a common radius to exceed the elastic limit of the material and subsequently mounting the material so that it is restrained in an unbent position on a substrate of nonmagnetic material. The elements are spot weld attached to a substrate to form a binary coded array of elements according to a desired binary code. The coded substrate may be enclosed in a plastic laminate structure. Such devices may be used for security badges, key cards, and the like and may have many other applications.

  14. Anatomy of the magnetic catalysis by renormalization-group method

    Science.gov (United States)

    Hattori, Koichi; Itakura, Kazunori; Ozaki, Sho

    2017-12-01

    We first examine the scaling argument for a renormalization-group (RG) analysis applied to a system subject to the dimensional reduction in strong magnetic fields, and discuss the fact that a four-Fermi operator of the low-energy excitations is marginal irrespective of the strength of the coupling constant in underlying theories. We then construct a scale-dependent effective four-Fermi interaction as a result of screened photon exchanges at weak coupling, and establish the RG method appropriately including the screening effect, in which the RG evolution from ultraviolet to infrared scales is separated into two stages by the screening-mass scale. Based on a precise agreement between the dynamical mass gaps obtained from the solutions of the RG and Schwinger-Dyson equations, we discuss an equivalence between these two approaches. Focusing on QED and Nambu-Jona-Lasinio model, we clarify how the properties of the interactions manifest themselves in the mass gap, and point out an importance of respecting the intrinsic energy-scale dependences in underlying theories for the determination of the mass gap. These studies are expected to be useful for a diagnosis of the magnetic catalysis in QCD.

  15. Anatomy of the magnetic catalysis by renormalization-group method

    Directory of Open Access Journals (Sweden)

    Koichi Hattori

    2017-12-01

    Full Text Available We first examine the scaling argument for a renormalization-group (RG analysis applied to a system subject to the dimensional reduction in strong magnetic fields, and discuss the fact that a four-Fermi operator of the low-energy excitations is marginal irrespective of the strength of the coupling constant in underlying theories. We then construct a scale-dependent effective four-Fermi interaction as a result of screened photon exchanges at weak coupling, and establish the RG method appropriately including the screening effect, in which the RG evolution from ultraviolet to infrared scales is separated into two stages by the screening-mass scale. Based on a precise agreement between the dynamical mass gaps obtained from the solutions of the RG and Schwinger–Dyson equations, we discuss an equivalence between these two approaches. Focusing on QED and Nambu–Jona-Lasinio model, we clarify how the properties of the interactions manifest themselves in the mass gap, and point out an importance of respecting the intrinsic energy-scale dependences in underlying theories for the determination of the mass gap. These studies are expected to be useful for a diagnosis of the magnetic catalysis in QCD.

  16. Magnetic Properties of Copper Doped Nickel Ferrite Nanoparticles Synthesized by Co Precipitation Method

    Science.gov (United States)

    Anjana, V.; John, Sara; Prakash, Pooja; Nair, Amritha M.; Nair, Aravind R.; Sambhudevan, Sreedha; Shankar, Balakrishnan

    2018-02-01

    Nickel ferrite nanoparticles with copper atoms as dopant have been prepared using co-precipitation method with general formula Ni1-xCuxFe2O4 (x=0.2, 0.4, 0.6, 0.8 and 1) and are sintered at quite ambient temperature. Structural and magnetic properties were examined using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction method (XRD) and Vibrating Sample Magnetometer (VSM) to study the influence of copper doping in nickel ferrite magnetic nanoparticles. X-ray studies proves that the particles are possessing single phase spinel structure with an average particle size calculated using Debye Scherer formula. Magnetic measurements reveal that saturation magnetization value (Ms) decreases while magnetic coercivity (Hc) increases upon doping.

  17. A study on metastable superconducting magnets

    International Nuclear Information System (INIS)

    Koyama, Kenichi

    1976-01-01

    It is important to construct superconducting magnets as cheap as possible. One of the methods to achieve such a purpose is to save the superconducting material and operate the magnets at a high current density. Therefore it is useful to investigate the requirements for the operation of metastable superconducting magnets which can work at a current higher than the recovery current. Using the theory of flux jump, we introduce a ''stable current'' below which no flux jump can occur. On a rough approximation, it is given by I sub(s) =√A P sub(i) H sub(e) T sub(o) f(x)/rho where A : cross-section of the composite conductor. P sub(i) : total perimeter of all the superconducting cores. h sub(e) : effective heat transfer coefficient to the liquid helium through the stabilizer. T sub(o) : a characteristic temperature of the superconducting cores. f(x) : a characteristic function for the relative core radius x. rho : effective resistivity of the composite. Then it is shown that superconducting magnets can operate without unexpected normal transitions in the region enclosed by the two curves of I sub(s) and I sub(c). Next, we discuss the characteristics of our saddle shaped superconducting magnet for an one-KW MHD generator. We found that, 1) the magnet does safely operate in the metastable state; 2) the characteristics of the magnet are consistent with our theoretical results. (auth.)

  18. Studies of magnetic resonance in anemia of hematies falciformes

    International Nuclear Information System (INIS)

    Lores Guevara, Manuel Arsenio; Balcom, Bruce John; Cabal Mirabal, Carlos

    2012-01-01

    Magnetic Resonance applications to the study of Sickle Cell Disease are analyzed using classical procedures and Unilateral Magnetic Resonance. Hemoglobin and whole blood samples were obtained from healthy individual and patients with Sickle Cell Anemia to be used as samples. Classical pulse sequence as spin echo and inversion recovery were used in the experimental studies, the STEPR method was used for EPR spectrometric determinations. The results show the possibility of NMR methods to follow the molecular process causing the disease and allows to present quantitative procedures to estimate the clinical state of the patients and the results of clinical options. We present the Unilateral Magnetic Resonance as a new method to study Sickle Cell disease considering its portability and new possibilities as new image method

  19. Interaction of magnetic resonators studied by the magnetic field enhancement

    Directory of Open Access Journals (Sweden)

    Yumin Hou

    2013-12-01

    Full Text Available It is the first time that the magnetic field enhancement (MFE is used to study the interaction of magnetic resonators (MRs, which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  20. Transportation studies: 40-MM collider dipole magnets

    International Nuclear Information System (INIS)

    Daly, E.

    1992-01-01

    Several fully functional 40-mm Collider Dipole Magnets (CDM) were instrumented with accelerometers to monitor shock and vibration loads during transport. The magnets were measured with optical tooling telescopes before and after transport. Changes in mechanical alignment due to shipping and handling were determined. The mechanical stability of the cryogen lines were checked using the same method. Field quality and dipole angle were measured warm before and after transport to determine changes in these parameters. Power spectra were calculated for accelerometers located on the cold mass, vacuum vessel, and trailer bed. Where available, plots of field quality and dipole roll both before and after were created. Shipping loads measured were largest in the vertical direction, where most of the structural deformation of the magnet was evident. It was not clear that magnetic performance was affected by the shipping and handling environment

  1. Three magnetic particles solid phase radioimmunoassay for T4: Comparison of their results with established methods

    International Nuclear Information System (INIS)

    Bashir, T.

    1996-01-01

    The introduction of solid phase separation techniques is an important improvement in radioimmunoassays and immunoradiometric assays. Magnetic particle solid phase method has additional advantages over others, as the separation is rapid and centrifugation is not required. Three types of magnetic particles have been studied in T 4 RIA and the results have been compared with commercial kits and other established methods. (author). 4 refs, 9 figs, 2 tabs

  2. Stochastic field-line wandering in magnetic turbulence with shear. II. Decorrelation trajectory method

    Science.gov (United States)

    Negrea, M.; Petrisor, I.; Shalchi, A.

    2017-11-01

    We study the diffusion of magnetic field lines in turbulence with magnetic shear. In the first part of the series, we developed a quasi-linear theory for this type of scenario. In this article, we employ the so-called DeCorrelation Trajectory method in order to compute the diffusion coefficients of stochastic magnetic field lines. The magnetic field configuration used here contains fluctuating terms which are described by the dimensionless functions bi(X, Y, Z), i = (x, y) and they are assumed to be Gaussian processes and are perpendicular with respect to the main magnetic field B0. Furthermore, there is also a z-component of the magnetic field depending on radial coordinate x (representing the gradient of the magnetic field) and a poloidal average component. We calculate the diffusion coefficients for magnetic field lines for different values of the magnetic Kubo number K, the dimensionless inhomogeneous magnetic parallel and perpendicular Kubo numbers KB∥, KB⊥ , as well as Ka v=bya vKB∥/KB⊥ .

  3. Is There a Magnet-School Effect? A Multisite Study of MSAP-Funded Magnet Schools

    Science.gov (United States)

    Wang, Jia; Schweig, Jonathan D.; Herman, Joan L.

    2017-01-01

    Magnet schools are one of the largest sectors of choice schools in the United States. In this study, we explored the heterogeneity in magnet-school effects on student achievement by examining 24 magnet schools, funded under the Magnet Schools Assistance Program (MSAP), in 5 school districts across 4 states. The magnet effects were synthesized…

  4. Method and device for thermal control of biological and chemical reactions using magnetic particles or magnetic beads and variable magnetic fields

    OpenAIRE

    Zilch, C.; Gerdes, W.; Bauer, J.; Holschuh, K.

    2009-01-01

    The invention relates to a method for the thermal control of at least one temperature-dependent enzymatic reaction in the presence of magnetic particles, particularly nanoparticles, or magnetic beads, in vitro by heating the magnetic beads or magnetic particles to at least one defined target temperature using alternating magnetic fields. The thermally controllable enzymatic reaction carried out with the method according to the invention is preferably a PCR reaction or another reaction for elo...

  5. U Exploration Using Magnetic Method On Bubu Sector, West Kalimantan

    International Nuclear Information System (INIS)

    Nurdin, M.; Subardjo; Darmono, S.; Slamet, S.

    1996-01-01

    The exploration was based on the discovery of association of U mineralization with magnetite, ilmenite, pyrite and pyrrhotite minerals which are fill in the NW-SE fracturations The aim and objective of exploration is to find depth and size of sub surface mineralization zone Magnetic method was chosen because the method was good for metallic detection The measured and plotted as contour map is total magnetic field; from the contour map shown there are 4 NW-SE magnetic poles The result of the modelling body using Geosoft Software was gotten 2 dimension of mineralization. The result of stacking the model on the geological map is width of the zone; it is 25 meter and the depth about 3.5 meter in quartzite and pyrrhotite, has NW-SE direction and controlled by structure

  6. A regularization method for extrapolation of solar potential magnetic fields

    Science.gov (United States)

    Gary, G. A.; Musielak, Z. E.

    1992-01-01

    The mathematical basis of a Tikhonov regularization method for extrapolating the chromospheric-coronal magnetic field using photospheric vector magnetograms is discussed. The basic techniques show that the Cauchy initial value problem can be formulated for potential magnetic fields. The potential field analysis considers a set of linear, elliptic partial differential equations. It is found that, by introducing an appropriate smoothing of the initial data of the Cauchy potential problem, an approximate Fourier integral solution is found, and an upper bound to the error in the solution is derived. This specific regularization technique, which is a function of magnetograph measurement sensitivities, provides a method to extrapolate the potential magnetic field above an active region into the chromosphere and low corona.

  7. Novel axolotl cardiac function analysis method using magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Pedro Gomes Sanches

    Full Text Available The salamander axolotl is capable of complete regeneration of amputated heart tissue. However, non-invasive imaging tools for assessing its cardiac function were so far not employed. In this study, cardiac magnetic resonance imaging is introduced as a non-invasive technique to image heart function of axolotls. Three axolotls were imaged with magnetic resonance imaging using a retrospectively gated Fast Low Angle Shot cine sequence. Within one scanning session the axolotl heart was imaged three times in all planes, consecutively. Heart rate, ejection fraction, stroke volume and cardiac output were calculated using three techniques: (1 combined long-axis, (2 short-axis series, and (3 ultrasound (control for heart rate only. All values are presented as mean ± standard deviation. Heart rate (beats per minute among different animals was 32.2±6.0 (long axis, 30.4±5.5 (short axis and 32.7±4.9 (ultrasound and statistically similar regardless of the imaging method (p > 0.05. Ejection fraction (% was 59.6±10.8 (long axis and 48.1±11.3 (short axis and it differed significantly (p = 0.019. Stroke volume (μl/beat was 133.7±33.7 (long axis and 93.2±31.2 (short axis, also differed significantly (p = 0.015. Calculations were consistent among the animals and over three repeated measurements. The heart rate varied depending on depth of anaesthesia. We described a new method for defining and imaging the anatomical planes of the axolotl heart and propose one of our techniques (long axis analysis may prove useful in defining cardiac function in regenerating axolotl hearts.

  8. Study on Magnetic Responsibility of Rare Earth Ferrite/Polyacrylamide Magnetic Microsphere

    Institute of Scientific and Technical Information of China (English)

    Zhang Ming; Wang Zhifeng; Zhang Hong; Dai Shaojun; Qiu Guanming; Okamoto Hiroshi

    2005-01-01

    In inverse microemulsion, rare earth ferrite/polyacrylamide magnetic microsphere were prepared and their magnetic responsibility were studied by magnetic balance. Results indicate that the magnetic responsibility of microsphere relates to magnetic moment of rare earth ion, and it can be improved by the addition of dysprosium ion of high magnetic moment. Dysprosium content has an effect on magnetic responsibility of dysprosium ferrite/polyacrylamide magnetic microsphere. The microsphere displays strong magnetic responsibility when the molar ratio of Dy3+/iron is 0.20.

  9. [DNA extraction from decomposed tissue by double-digest and magnetic beads methods].

    Science.gov (United States)

    Yang, Dian; Liu, Chao; Liu, Hong

    2011-12-01

    To study the effect of the double-digest and magnetic beads method for DNA extraction from 3 types of decomposed tissues. DNA of cartilages, nails and joint capsule in 91 highly decomposed corpses which had not been extracted by common magnetic beads method, were prepared with the double-digest and magnetic beads methods, and quantified with Quantifiler kit, followed by amplification with Sinofiler kit or Minifiler kit. DNA concentration extracted from the 91 highly decomposed cartilages, nails and joint capsule samples was 0-0.225 ng/microL. Sixty-two samples whose DNA concentration were more than 0.020 ng/microL had obtained 9 or more STR loci successfully. The detection rate was 68.13%. The successful rate of STR genotyping for the 3 types of decomposed tissues can be significantly improved by the double-digest and magnetic beads methods.

  10. 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)

  11. A Study on Magnetic Decoupling of Compound-Structure Permanent-Magnet Motor for HEVs Application

    Directory of Open Access Journals (Sweden)

    Qiwei Xu

    2016-10-01

    Full Text Available The compound-structure permanent-magnet (CSPM motor is used for an electrical continuously-variable transmission (E-CVT in a hybrid electric vehicle (HEV. It can make the internal combustion engine (ICE independent of the road loads and run in the high efficiency area to improve the fuel economy and reduce the emissions. This paper studies the magnetic coupling of a new type of CSPM motor used in HEVs. Firstly, through the analysis of the parameter matching with CSPM in the HEV, we receive the same dynamic properties’ design parameters between the CSPM motor and the THS (Toyota Hybrid System of the Toyota Prius. Next, we establish the equivalent magnetic circuit model of the overall and the secondary model considering the tangential and radial flux distribution in the outer rotor of the CSPM motor. Based on these two models, we explore the internal magnetic coupling rule of the CSPM motor. Finally, finite element method analysis in 2D-ansoft is used to analyze the magnetic field distribution of the CSPM motor in different operation modes. By the result of the finite element method analysis, the internal magnetic decoupling scheme is put forward, laying the theoretical foundation for the further application of the CSPM motor in HEVs.

  12. Influence of preparation method on structural and magnetic ...

    Indian Academy of Sciences (India)

    Administrator

    Influence of preparation method on structural and magnetic properties of nickel ferrite nanoparticles. BINU P JACOB, ASHOK KUMAR†, R P PANT†, SUKHVIR SINGH† and. E M MOHAMMED*. Department of Physics, Maharaja's College, Ernakulam 681 011, India. †National Physical Laboratory, New Delhi 110 012, India.

  13. Magnetic characterisation of recording materials: design, instrumentation and experimental methods

    NARCIS (Netherlands)

    Samwel, E.O.

    1995-01-01

    The progress being made in the field of magnetic recording is extremely fast. The need to keep this progress going, leads to new types of recording materials which require advanced measurement systems and measurement procedures. Furthermore, the existing measurement methods need to be reviewed as

  14. Fabrication of Co thin films using pulsed laser deposition method with or without employing external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Ehsani, M.H., E-mail: Ehsani@semnan.ac.ir [Thin Film Laboratory, Faculty of Physics, Semnan University (Iran, Islamic Republic of); Mehrabad, M. Jalali [Thin Film Laboratory, Faculty of Physics, Semnan University (Iran, Islamic Republic of); Kameli, P. [Department of Physics, Isfahan University of technology, Isfahan 8415683111 (Iran, Islamic Republic of)

    2016-11-01

    In this work, the external magnetic field effects on growth condition during deposition processes of the Co thin films were studied. Two specimens of Co films with different condition (with and without external magnetic field) were synthesized by pulsed laser deposition method. Structural and magnetic properties of the Co thin films were systematically studied, using atomic force microscope analysis and magnetization measurement, respectively. During the deposition processes, the external applied magnetic field had been provided by a permanent magnet. The experimental results show that the external magnetic field enables one to tune the magnetic properties of the deposited thin films. To clarify this effect, using Multi-Physics COMSOL simulation environment, a study of vapor flux by applied magnetic field during deposition were performed. Comparison between experimental data and output data of the simulation show promising accommodation and approve the existence of a strong correlation between the structural and magnetic properties of the specimens, and deposition rate of Co thin films. - Graphical abstract: Simulation results of the cobalt particles tracing sputtered from the source to substrate with an external magnetic field. Convergence of the particles flux (left) and also the spiral motion of the cobalt particles (right) increase dramatically as they approach the substrate and NdFe35 magnet. - Highlights: • The external magnetic field effects on growth condition during deposition processes of the Co thin films were studied. • Structural and magnetic properties of the Co thin films were systematically studied, using atomic force microscope analysis and magnetization measurement, respectively. • The experimental results show that the external magnetic field enables one to tune the magnetic properties of the deposited thin films. • To clarify this effect, using Multi-Physics COMSOL simulation environment, a study of vapor flux by applied magnetic field

  15. Study of the polymer permanent magnets properties - rare earths

    International Nuclear Information System (INIS)

    Takiishi, H.; Benini, H.R.; Lima, L.F.C.P.; Faria, R.N.

    1996-01-01

    An alternative method for permanent magnet production without the sintering step is polymer bonded magnets. In this work magnets were prepared from magnetic Sm Co 5 or Nd 15 Fe 77 B 8 alloys bonded with 10% wt of resin. For the Nd 15 Fe 77 B 8 alloy the hydrogenation - decomposition - desorption - recombination (HDDR) process have been employed in the preparation of the magnets. Results from the magnetic properties showed that no milling is necessary for the production of polymer bonded Nd-Fe-B magnets. The magnets showed good magnetic properties. (author)

  16. Magnetic hyperthermia heating of cobalt ferrite nanoparticles prepared by low temperature ferrous sulfate based method

    Directory of Open Access Journals (Sweden)

    Tejabhiram Yadavalli

    2016-05-01

    Full Text Available A facile low temperature co-precipitation method for the synthesis of crystalline cobalt ferrite nanostructures using ferrous sulfate salt as the precursor has been discussed. The prepared samples were compared with nanoparticles prepared by conventional co-precipitation and hydrothermal methods using ferric nitrate as the precursor. X-ray diffraction studies confirmed the formation of cubic spinel cobalt ferrites when dried at 110 °C as opposed to conventional methods which required higher temperatures/pressure for the formation of the same. Field emission scanning electron microscope studies of these powders revealed the formation of nearly spherical nanostructures in the size range of 20-30 nm which were comparable to those prepared by conventional methods. Magnetic measurements confirmed the ferromagnetic nature of the cobalt ferrites with low magnetic remanance. Further magnetic hyperthermia studies of nanostructures prepared by low temperature method showed a rise in temperature to 50 °C in 600 s.

  17. A new method to determine magnetic properties of the unsaturated-magnetized rotor of a novel gyro

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hai, E-mail: lihai7772006@126.com [MEMS Center, Harbin Institution of Technology, Harbin, 150001 (China); Liu, Xiaowei [MEMS Center, Harbin Institution of Technology, Harbin, 150001 (China); Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Ministry of Education, Harbin, 150001 (China); Dong, Changchun [School of Software, Harbin University of Science and Technology, Harbin, 150001 (China); Zhang, Haifeng [MEMS Center, Harbin Institution of Technology, Harbin, 150001 (China)

    2016-06-01

    A new method is proposed to determine magnetic properties of the unsaturated-magnetized, small and irregular shaped rotor of a novel gyro. The method is based on finite-element analysis and the measurements of the magnetic flux density distribution, determining magnetic parameters by comparing the magnetic flux intensity distribution differences between the modeling results under different parameters and the measured ones. Experiment on a N30 Grade NdFeB magnet shows that its residual magnetic flux density is 1.10±0.01 T, and coercive field strength is 801±3 kA/m, which are consistent with the given parameters of the material. The method was applied to determine the magnetic properties of the rotor of the gyro, and the magnetic properties acquired were used to predict the open-loop gyro precession frequency. The predicted precession frequency should be larger than 12.9 Hz, which is close to the experimental result 13.5 Hz. The result proves that the method is accurate in estimating the magnetic properties of the rotor of the gyro. - Highlights: • A new method to determine the magnetic properties of a gyro’s rotor is proposed. • The method is based on FEA and magnetic flux density distributions near magnets. • The result is determined by the distribution and values of all the measured points. • Using the result, the open-loop gyro precession frequency is precisely predicted.

  18. A new method to determine magnetic properties of the unsaturated-magnetized rotor of a novel gyro

    International Nuclear Information System (INIS)

    Li, Hai; Liu, Xiaowei; Dong, Changchun; Zhang, Haifeng

    2016-01-01

    A new method is proposed to determine magnetic properties of the unsaturated-magnetized, small and irregular shaped rotor of a novel gyro. The method is based on finite-element analysis and the measurements of the magnetic flux density distribution, determining magnetic parameters by comparing the magnetic flux intensity distribution differences between the modeling results under different parameters and the measured ones. Experiment on a N30 Grade NdFeB magnet shows that its residual magnetic flux density is 1.10±0.01 T, and coercive field strength is 801±3 kA/m, which are consistent with the given parameters of the material. The method was applied to determine the magnetic properties of the rotor of the gyro, and the magnetic properties acquired were used to predict the open-loop gyro precession frequency. The predicted precession frequency should be larger than 12.9 Hz, which is close to the experimental result 13.5 Hz. The result proves that the method is accurate in estimating the magnetic properties of the rotor of the gyro. - Highlights: • A new method to determine the magnetic properties of a gyro’s rotor is proposed. • The method is based on FEA and magnetic flux density distributions near magnets. • The result is determined by the distribution and values of all the measured points. • Using the result, the open-loop gyro precession frequency is precisely predicted.

  19. New Cogging Torque Reduction Methods for Permanent Magnet Machine

    Science.gov (United States)

    Bahrim, F. S.; Sulaiman, E.; Kumar, R.; Jusoh, L. I.

    2017-08-01

    Permanent magnet type motors (PMs) especially permanent magnet synchronous motor (PMSM) are expanding its limbs in industrial application system and widely used in various applications. The key features of this machine include high power and torque density, extending speed range, high efficiency, better dynamic performance and good flux-weakening capability. Nevertheless, high in cogging torque, which may cause noise and vibration, is one of the threat of the machine performance. Therefore, with the aid of 3-D finite element analysis (FEA) and simulation using JMAG Designer, this paper proposed new method for cogging torque reduction. Based on the simulation, methods of combining the skewing with radial pole pairing method and skewing with axial pole pairing method reduces the cogging torque effect up to 71.86% and 65.69% simultaneously.

  20. 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.

  1. Generalized matrix method for transmission of neutrons through multilayer magnetic system with non-colinear magnetization

    International Nuclear Information System (INIS)

    Radu, F.; Ignatovich, V.K.

    1999-01-01

    A generalized matrix method (GMM) for reflection and transmission of polarized and nonpolarized neutrons for multilayer systems with non-colinear magnetization of neighboring layers is developed. Several methods exist for calculation of the reflection and transmission coefficients of the multilayer systems (MS). We consider here only two of them. One is the recurrence method (RM), and another one is the matrix method. Previously these methods were used for scalar particles and for spinor particles. In the last case a limitation was imposed on the directions of the magnetization of different layers: they were required to lie in the plane parallel to the layers. In 1995 Fermon has described a different approach of the neutrons in MS. Here, the behaviour of the wave inside the layers depends on the position within the plane. The RM, as shown by us earlier, permits to treat multilayer systems with arbitrary directions of the magnetization. We show how to treat these systems with the updated matrix method, which we call the generalized matrix method. In the GMM method the transmission and reflection of a layered system are obtained by finding a 4 x 4 matrix, which is a product of elementary 4 x 4 matrices related to the different layers, and in the RM the solution is found by recurrent application of the same procedure of finding the reflection and transmission matrices for a continuously increasing number of layers. The RM method permits to use a simple algorithm to write analytical formulas for the reflection and transmission. However, for more or less complicated systems these formulas become useless and one needs to do numerical calculations. The GMM does not give a simple analytical algorithm, but it gives a very simple numerical algorithm. We have developed two computer codes for computing the coefficients of reflection and transmission of a layered system using the GMM and RM methods. The calculated reflectivities R ++ and R +- for a polarized beam which fall on

  2. Modelling magnetic polarisation J 50 by different methods

    International Nuclear Information System (INIS)

    Yonamine, Taeko; Campos, Marcos F. de; Castro, Nicolau A.; Landgraf, Fernando J.G.

    2006-01-01

    Two different methods for modelling the angular behaviour of magnetic polarisation at 5000 A/m (J 50 ) of electrical steels were evaluated and compared. Both methods are based upon crystallographic texture data. The texture of non-oriented electrical steels with silicon content ranging from 0.11 to 3%Si was determined by X-ray diffraction. In the first method, J 50 was correlated to the calculated value of the average anisotropy energy in each direction, using texture data. In the second method, the first three coefficients of the spherical harmonic series of the ODF and two experimental points were used to estimate the angular variation of J 50 . The first method allows the estimation of J 50 for samples with different textures and Si contents using only the texture data, with no need of magnetic measurement, and this is advantageous, because texture data can be acquired with less than 2 g of material. The second method may give better adjust in some situations but besides the texture data, it requests magnetic measurements in at least two directions, for example, rolling and transverse directions

  3. Magnetic resonance cell-tracking studies: spectrophotometry-based method for the quantification of cellular iron content after loading with superparamagnetic iron oxide nanoparticles.

    Science.gov (United States)

    Böhm, Ingrid

    2011-08-01

    The purpose of this article is to present a user-friendly tool for quantifying the iron content of superparamagnetic labeled cells before cell tracking by magnetic resonance imaging (MRI). Iron quantification was evaluated by using Prussian blue staining and spectrophotometry. White blood cells were labeled with superparamagnetic iron oxide (SPIO) nanoparticles. Labeling was confirmed by light microscopy. Subsequently, the cells were embedded in a phantom and scanned on a 3 T magnetic resonance tomography (MRT) whole-body system. Mean peak wavelengths λ(peak) was determined at A(720 nm) (range 719-722 nm). Linearity was proven for the measuring range 0.5 to 10 μg Fe/mL (r  =  .9958; p  =  2.2 × 10(-12)). The limit of detection was 0.01 μg Fe/mL (0.1785 mM), and the limit of quantification was 0.04 μg Fe/mL (0.714 mM). Accuracy was demonstrated by comparison with atomic absorption spectrometry. Precision and robustness were also proven. On T(2)-weighted images, signal intensity varied according to the iron concentration of SPIO-labeled cells. Absorption spectrophotometry is both a highly sensitive and user-friendly technique that is feasible for quantifying the iron content of magnetically labeled cells. The presented data suggest that spectrophotometry is a promising tool for promoting the implementation of magnetic resonance-based cell tracking in routine clinical applications (from bench to bedside).

  4. Magnetic Resonance Cell-Tracking Studies: Spectrophotometry-Based Method for the Quantification of Cellular Iron Content after Loading with Superparamagnetic Iron Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Ingrid Böhm

    2011-07-01

    Full Text Available The purpose of this article is to present a user-friendly tool for quantifying the iron content of superparamagnetic labeled cells before cell tracking by magnetic resonance imaging (MRI. Iron quantification was evaluated by using Prussian blue staining and spectrophotometry. White blood cells were labeled with superparamagnetic iron oxide (SPIO nanoparticles. Labeling was confirmed by light microscopy. Subsequently, the cells were embedded in a phantom and scanned on a 3 T magnetic resonance tomography (MRT whole-body system. Mean peak wavelengths Λpeak was determined at A720nm (range 719–722 nm. Linearity was proven for the measuring range 0.5 to 10 μg Fe/mL (r = .9958; p = 2.2 × 10−12. The limit of detection was 0.01 μg Fe/mL (0.1785 mM, and the limit of quantification was 0.04 μg Fe/mL (0.714 mM. Accuracy was demonstrated by comparison with atomic absorption spectrometry. Precision and robustness were also proven. On T2-weighted images, signal intensity varied according to the iron concentration of SPIO-labeled cells. Absorption spectrophotometry is both a highly sensitive and user-friendly technique that is feasible for quantifying the iron content of magnetically labeled cells. The presented data suggest that spectrophotometry is a promising tool for promoting the implementation of magnetic resonance-based cell tracking in routine clinical applications (from bench to bedside.

  5. A study of the methods for the production and confinement of high energy plasmas. [injection of dense plasma into long magnetic field

    Science.gov (United States)

    Cheng, D. Y.; Wang, P.

    1972-01-01

    The injection of dense plasmas into a B sub z long magnetic field from both ends of the field coil was investigated. Deflagration plasma guns and continuous flow Z-pinch are discussed along with the possibility of a continuous flow Z-pinch fusion reactor. The injection experiments are described with emphasis on the synchronization of the two plasma deflagration guns, the collision of the two plasma beams, and the determination of plasma density.

  6. A biodetection method using magnetic particles and micro traps

    KAUST Repository

    Li, Fuquan

    2012-03-09

    The general working principle of magnetoresistive sensors for biological applications is to specifically attach bioanalytesto magnetic particles and then detect the particles that are immobilized on the sensor surface. The immobilization of the particles on the sensor surface commonly uses biomolecular interactions, e.g., antigen-antibody. Thus, the sensor surface needs to be functionalized via biological treatments in order to capture certain bioanalytes. In the presented work, a new method is proposed, which does not rely on functionalization of the sensor surface. Current carrying microstructures in combination with mechanical micro traps are used to immobilize magnetic particles. Analyte detection is based on the difference in size between bare magnetic particles and particles with analyte attached, which causes a different number of particles to be captured in the micro traps.

  7. Implicit Methods for the Magnetohydrodynamic Description of Magnetically Confined Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Jardin, S C

    2010-09-28

    Implicit algorithms are essential for predicting the slow growth and saturation of global instabilities in today’s magnetically confined fusion plasma experiments. Present day algorithms for obtaining implicit solutions to the magnetohydrodynamic (MHD) equations for highly magnetized plasma have their roots in algorithms used in the 1960s and 1970s. However, today’s computers and modern linear and non-linear solver techniques make practical much more comprehensive implicit algorithms than were previously possible. Combining these advanced implicit algorithms with highly accurate spatial representations of the vector fields describing the plasma flow and magnetic fields and with improved methods of calculating anisotropic thermal conduction now makes possible simulations of fusion experiments using realistic values of plasma parameters and actual configuration geometry.

  8. Implicit Methods for the Magnetohydrodynamic Description of Magnetically Confined Plasmas

    International Nuclear Information System (INIS)

    Jardin, S.C.

    2010-01-01

    Implicit algorithms are essential for predicting the slow growth and saturation of global instabilities in today's magnetically confined fusion plasma experiments. Present day algorithms for obtaining implicit solutions to the magnetohydrodynamic (MHD) equations for highly magnetized plasma have their roots in algorithms used in the 1960s and 1970s. However, today's computers and modern linear and non-linear solver techniques make practical much more comprehensive implicit algorithms than were previously possible. Combining these advanced implicit algorithms with highly accurate spatial representations of the vector fields describing the plasma flow and magnetic fields and with improved methods of calculating anisotropic thermal conduction now makes possible simulations of fusion experiments using realistic values of plasma parameters and actual configuration geometry.

  9. Method and Apparatus of Implementing a Magnetic Shield Flux Sweeper

    Science.gov (United States)

    Sadleir, John E. (Inventor)

    2018-01-01

    The present invention relates to a method and apparatus of protecting magnetically sensitive devices with a shield, including: a non-superconducting metal or lower transition temperature (T.sub.c) material compared to a higher transition temperature material, disposed in a magnetic field; means for creating a spatially varying order parameter's |.PSI.(r,T)|.sup.2 in a non-superconducting metal or a lower transition temperature material; wherein a spatially varying order parameter is created by a proximity effect, such that the non-superconducting metal or the lower transition temperature material becomes superconductive as a temperature is lowered, creating a flux-free Meissner state at a center thereof, in order to sweep magnetic flux lines to the periphery.

  10. METHOD AND APPARATUS FOR TRAPPING IONS IN A MAGNETIC FIELD

    Science.gov (United States)

    Luce, J.S.

    1962-04-17

    A method and apparatus are described for trapping ions within an evacuated container and within a magnetic field utilizing dissociation and/or ionization of molecular ions to form atomic ions and energetic neutral particles. The atomic ions are magnetically trapped as a result of a change of charge-to- mass ratio. The molecular ions are injected into the container and into the path of an energetic carbon arc discharge which dissociates and/or ionizes a portion of the molecular ions into atomic ions and energetic neutrals. The resulting atomic ions are trapped by the magnetic field to form a circulating beam of atomic ions, and the energetic neutrals pass out of the system and may be utilized in a particle accelerator. (AEC)

  11. Magnetic Alignment of Pulsed Solenoids Using the Pulsed Wire Method

    International Nuclear Information System (INIS)

    Arbelaez, D.; Madur, A.; Lipton, T.M.; Waldron, W.L.; Kwan, J.W.

    2011-01-01

    A unique application of the pulsed-wire measurement method has been implemented for alignment of 2.5 T pulsed solenoid magnets. The magnetic axis measurement has been shown to have a resolution of better than 25 (micro)m. The accuracy of the technique allows for the identification of inherent field errors due to, for example, the winding layer transitions and the current leads. The alignment system is developed for the induction accelerator NDCX-II under construction at LBNL, an upgraded Neutralized Drift Compression experiment for research on warm dense matter and heavy ion fusion. Precise alignment is essential for NDCX-II, since the ion beam has a large energy spread associated with the rapid pulse compression such that misalignments lead to corkscrew deformation of the beam and reduced intensity at focus. The ability to align the magnetic axis of the pulsed solenoids to within 100 pm of the induction cell axis has been demonstrated.

  12. Study on magnetic separation for decontamination of cesium contaminated soil by using superconducting magnet

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Susumu, E-mail: igarashi@qb.see.eng.osaka-u.ac.jp; Nomura, Naoki; Mishima, Fumihito; Akiyama, Yoko, E-mail: yoko-ak@see.eng.osaka-u.ac.jp

    2014-09-15

    Highlights: • The method for the soil decontamination by the superconducting magnet is proposed. • Magnetic separation of clay minerals was performed by HGMS. • Soil separation ratio was evaluated by quantitative analysis using XRD. • It is expected that HGMS can be applied to the actual soil decontamination. - Abstract: The accident of Fukushima Daiichi nuclear power plant caused the diffusion of radioactive cesium over the wide area. We examined the possibility of applying magnetic separation method using the superconducting magnet, which can process a large amount of the soil in high speed, to the soil decontamination and volume reduction of the radioactive cesium contaminated soil. Clay minerals are classified as 2:1 and 1:1 types by the difference of their layer structures, and these types of minerals are respectively paramagnetic and diamagnetic including some exception. It is known that most of the radioactive cesium is strongly adsorbed on the clay, especially on 2:1 type clay minerals. It is expected that the method which can separate only 2:1 type clay minerals selectively from the mixture clay minerals can enormously contribute to the volume reduction of the contaminated soil. In this study, the components in the clay before and after separation were evaluated to estimate the magnetic separation efficiency by using X-ray diffraction. From the results, the decontamination efficiency and the volume reduction ratio were estimated in order to examine the appropriate separation conditions for the practical decontamination of the soil.

  13. Quantitative magnetic resonance micro-imaging methods for pharmaceutical research.

    Science.gov (United States)

    Mantle, M D

    2011-09-30

    The use of magnetic resonance imaging (MRI) as a tool in pharmaceutical research is now well established and the current literature covers a multitude of different pharmaceutically relevant research areas. This review focuses on the use of quantitative magnetic resonance micro-imaging techniques and how they have been exploited to extract information that is of direct relevance to the pharmaceutical industry. The article is divided into two main areas. The first half outlines the theoretical aspects of magnetic resonance and deals with basic magnetic resonance theory, the effects of nuclear spin-lattice (T(1)), spin-spin (T(2)) relaxation and molecular diffusion upon image quantitation, and discusses the applications of rapid magnetic resonance imaging techniques. In addition to the theory, the review aims to provide some practical guidelines for the pharmaceutical researcher with an interest in MRI as to which MRI pulse sequences/protocols should be used and when. The second half of the article reviews the recent advances and developments that have appeared in the literature concerning the use of quantitative micro-imaging methods to pharmaceutically relevant research. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. A Novel Cogging Torque Simulation Method for Permanent-Magnet Synchronous Machines

    Directory of Open Access Journals (Sweden)

    Chun-Yu Hsiao

    2011-12-01

    Full Text Available Cogging torque exists between rotor mounted permanent magnets and stator teeth due to magnetic attraction and this is an undesired phenomenon which produces output ripple, vibration and noise in machines. The purpose of this paper is to study the existence and effects of cogging torque, and to present a novel, rapid, half magnet pole pair technique for forecasting and evaluating cogging torque. The technique uses the finite element method as well as Matlab research and development oriented software tools to reduce numerous computing jobs and simulation time. An example of a rotor-skewed structure used to reduce cogging torque of permanent magnet synchronous machines is evaluated and compared with a conventional analysis method for the same motor to verify the effectiveness of the proposed approach. The novel method is proved valuable and suitable for large-capacity machine design.

  15. Classification of Magnetic Nanoparticle Systems—Synthesis, Standardization and Analysis Methods in the NanoMag Project

    Directory of Open Access Journals (Sweden)

    Sara Bogren

    2015-08-01

    Full Text Available This study presents classification of different magnetic single- and multi-core particle systems using their measured dynamic magnetic properties together with their nanocrystal and particle sizes. The dynamic magnetic properties are measured with AC (dynamical susceptometry and magnetorelaxometry and the size parameters are determined from electron microscopy and dynamic light scattering. Using these methods, we also show that the nanocrystal size and particle morphology determines the dynamic magnetic properties for both single- and multi-core particles. The presented results are obtained from the four year EU NMP FP7 project, NanoMag, which is focused on standardization of analysis methods for magnetic nanoparticles.

  16. 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

  17. Spin-resolved magnetic studies of focused ion beam etched nano-sized magnetic structures

    International Nuclear Information System (INIS)

    Li Jian; Rau, Carl

    2005-01-01

    Scanning ion microscopy with polarization analysis (SIMPA) is used to study the spin-resolved surface magnetic structure of nano-sized magnetic systems. SIMPA is utilized for in situ topographic and spin-resolved magnetic domain imaging as well as for focused ion beam (FIB) etching of desired structures in magnetic or non-magnetic systems. Ultra-thin Co films are deposited on surfaces of Si(1 0 0) substrates, and ultra-thin, tri-layered, bct Fe(1 0 0)/Mn/bct Fe(1 0 0) wedged magnetic structures are deposited on fcc Pd(1 0 0) substrates. SIMPA experiments clearly show that ion-induced electrons emitted from magnetic surfaces exhibit non-zero electron spin polarization (ESP), whereas electrons emitted from non-magnetic surfaces such as Si and Pd exhibit zero ESP, which can be used to calibrate sputtering rates in situ. We report on new, spin-resolved magnetic microstructures, such as magnetic 'C' states and magnetic vortices, found at surfaces of FIB patterned magnetic elements. It is found that FIB milling has a negligible effect on surface magnetic domain and domain wall structures. It is demonstrated that SIMPA can evolve into an important and efficient tool to study magnetic domain, domain wall and other structures as well as to perform magnetic depth profiling of magnetic nano-systems to be used in ultra-high density magnetic recording and in magnetic sensors

  18. Reorientations in [Mg(H2O)6](CLO4)2 studied by the proton magnetic resonance and the quasielastic neutron scattering methods

    International Nuclear Information System (INIS)

    Svare, I.; Fimland, B.O.; Janik, J.A.; Janik, J.M.; Mikuli, E.; Migdal-Mikuli, A.

    1980-01-01

    Proton magnetic relaxation measurements carried out for [Mg(H 2 O)XL6](CLO 4 ) 2 revealed two processes responsible for T 1 vs temperature dependence: one connected with H 2 O 180deg flips about the symmetry axes and second connected with a tumbling of the complex cation. Quasielastic neutron scattering measurements gave another evidence of H 2 O 180deg flips. The reorientational corelation times, which in the 273 K - 325 K region are of the order of picoseconds, as derived from NMR coincide perfectly well with those derived from QNS. (author)

  19. Analysis of Electromagnetic Attractive Force : Examination by Magnetic Circuit, Finite Element Method and Experiment

    OpenAIRE

    薮野, 浩司; 大和田, 竜太郎; 青島, 伸治; Hiroshi, YABUNO; Ryotaro, OOWADA; Nobuharu, AOSHIMA; 筑波大学; 筑波大学院; 筑波大学

    1998-01-01

    This paper presents the limitation of the magnetic circuit method. The force between magnetic bodies can be approximated accurately by the magnetic circuit method. Therefore this method has been used widely for the estimation of magnetic force. However this method is limited by the magnetic leakage and can be not used in the case when the gap between the magnetic bodies is wide. It is very important to clarify the limitation of the magnetic circuit method. In this research, the force of an el...

  20. Uniaxial anisotropy in magnetite thin film-Magnetization studies

    International Nuclear Information System (INIS)

    Wiechec, A.; Korecki, J.; Handke, B.; Kakol, Z.; Owoc, D.; Antolak, D.A.; Kozlowski, A.

    2006-01-01

    Magnetization and electrical resistivity measurements have been performed on a stoichiometric single crystalline magnetite Fe 3 O 4 thin film (thickness of ca. 500 nm) MBE deposited on MgO (1 0 0) substrate. The aim of these studies was to check the influence of preparation method and sample form (bulk vs. thin film) on magnetic anisotropy properties in magnetite. The film magnetization along versus applied magnetic field has been determined both in the direction parallel and perpendicular to the film surface, and at temperatures above and below the Verwey transition. We have found, in agreement with published results, that the in-plane field of 10 kOe was not sufficient to saturate the sample. This can be understood if some additional factor, on top of the bulk magnetocrystalline anisotropy, is taken into account

  1. Size-dependent magnetic anisotropy of PEG coated Fe3O4 nanoparticles; comparing two magnetization methods

    Science.gov (United States)

    Nayek, C.; Manna, K.; Imam, A. A.; Alqasrawi, A. Y.; Obaidat, I. M.

    2018-02-01

    Understanding the size dependent magnetic anisotropy of iron oxide nanoparticles is essential for the successful application of these nanoparticles in several technological and medical fields. PEG-coated iron oxide (Fe3O4) nanoparticles with core diameters of 12 nm, 15 nm, and 16 nm were synthesized by the usual co-precipitation method. The morphology and structure of the nanoparticles were investigated using transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD). Magnetic measurements were conducted using a SQUID. The effective magnetic anisotropy was calculated using two methods from the magnetization measurements. In the first method the zero-field-cooled magnetization versus temperature measurements were used at several applied magnetic fields. In the second method we used the temperature-dependent coercivity curves obtained from the zero-field-cooled magnetization versus magnetic field hysteresis loops. The role of the applied magnetic field on the effective magnetic anisotropy, calculated form the zero-field-cooled magnetization versus temperature measurements, was revealed. The size dependence of the effective magnetic anisotropy constant Keff obtained by the two methods are compared and discussed.

  2. Comparison of methods for cryostating superconducting dipole magnets

    International Nuclear Information System (INIS)

    Son Zun Gan; Filippov, Yu.P.; Zinchenko, S.I.

    1985-01-01

    An attempt is made to refine basic parameters of the UNK cryogenic system with account of real characteristics of horizontal two-phase helium flows and to project ways of optimizing these parameters. The method 1 where liquid helium in the state close to saturation is supplied to the chain of magnets and removes heat releasing in coils and coming from environment at the expense of phase transformation and it leaves the chain as vapour-liquid mixture, is compared with the method 2 where magnet cooling is arranged at the expense of heat transfer from one-phase direct flow to two-phase helium counter flow. The results of calculations are presented as dependences of maximum temperatures of coils on the length of magnetic path. It is shown that at the length of chain of about 300-400 m both methods are practically equivalent by temperature criterion, but the method 1 is preferable due to simpler design of the cryostat and lesser helium quantity in the system

  3. Monitoring of magnetic EOR fluids in reservoir under production by using the electromagnetic method

    Science.gov (United States)

    KIM, S.; Min, D. J.; Moon, S.; Kim, W. K.; Shin, Y.

    2014-12-01

    To increase the amount of oil and gas extracted during production, some techniques like EOR (Enhanced Oil Recovery) are applied by injecting some materials such as water and CO2. Recently, there are some researches for injecting magnetic nanoparticles with fluids during EOR. The size of particle is nano-scale, which can prevent particles from adhering to the pores of reservoir. The main purpose of injecting magnetic nanoparticles is to monitor movement or distribution of EOR fluids. To monitor the injected magnetic EOR fluids in the reservoir, CSEM (controlled source electromagnetic method) can be the most optimized geophysical method among various geophysical monitoring methods. Depending on the reservoir circumstances, we can control the electric or magnetic sources to monitor reservoir during oil or gas production. In this study, we perform numerical simulation of CSEM for 3D horizontal-layered models assuming a reservoir under production. We suppose that there are two wells: one is for the controlled source; the other is for the receiver. By changing the distribution, movement and magnetization of EOR fluids, we compare the electric or magnetic fields recorded at the receiver. Maxwell's equations are the governing equation of CSEM and are approximated by using the edge-based finite-element method. Direct solver is applied to solve the linear equations. Because injected magnetic nanoparticle changes the conductivity of EOR fluid, there is high contrast of conductivity of reservoir. This high contrast of conductivity induces secondary electric or magnetic fields that are recorded at the receiver well. We compare these recorded secondary fields generated by various movement or distribution of magnetic EOR fluid. Acknowledgements This work was supported by the "Development of Technology for CO2 Marine Geological Storage" grant funded by the Ministry of Oceans and Fisheries of Korea, by the "Civil Military Technology Cooperation Center", and by the International

  4. A novel superconducting magnetic levitation method to support the laser fusion capsule by using permanent magnets

    Directory of Open Access Journals (Sweden)

    Xiaojia Li

    2018-05-01

    Full Text Available A novel magnetic levitation support method is proposed, which can relieve the perturbation caused by traditional support methods and provide more accurate position control of the capsule. This method can keep the perfect symmetry of the octahedral spherical hohlraum and has the characteristics in stability, tunability and simplicity. It is also favorable that all the results, such as supporting forces acting on the superconducting capsule, are calculated analytically, and numerical simulations are performed to verify these results. A typical realistic design is proposed and discussed in detail. The superconducting coating material is suggested, and the required superconducting properties are listed. Damped oscillation of the floating capsule in thin helium gas is discussed, and the restoring time is estimated. Keywords: ICF capsule support, Magnetic levitation, Symmetry, PACS Codes: 52.57.Fg, 74.70.Ad, 74.78.-W

  5. Comparison among T1-Weighted Magnetic Resonance Imaging, Modified Dixon Method, and Magnetic Resonance Spectroscopy in Measuring Bone Marrow Fat

    Directory of Open Access Journals (Sweden)

    Wei Shen

    2013-01-01

    Full Text Available Introduction. An increasing number of studies are utilizing different magnetic resonance (MR methods to quantify bone marrow fat due to its potential role in osteoporosis. Our aim is to compare the measurements of bone marrow fat among T1-weighted magnetic resonance imaging (MRI, modified Dixon method (also called fat fraction MRI (FFMRI, and magnetic resonance spectroscopy (MRS. Methods. Contiguous MRI scans were acquired in 27 Caucasian postmenopausal women with a modified Dixon method (i.e., FFMRI. Bone marrow adipose tissue (BMAT of T1-weighted MRI and bone marrow fat fraction of the L3 vertebra and femoral necks were quantified using SliceOmatic and Matlab. MRS was also acquired at the L3 vertebra. Results. Correlation among the three MR methods measured bone marrow fat fraction and BMAT ranges from 0.78 to 0.88 in the L3 vertebra. Correlation between BMAT measured by T1-weighted MRI and bone marrow fat fraction measured by modified FFMRI is 0.86 in femoral necks. Conclusion. There are good correlations among T1-weighted MRI, FFMRI, and MRS for bone marrow fat quantification. The inhomogeneous distribution of bone marrow fat, the threshold segmentation of the T1-weighted MRI, and the ambiguity of the FFMRI may partially explain the difference among the three methods.

  6. A study on stability of rotating magnets

    International Nuclear Information System (INIS)

    Higuchi, N.; Kaiho, K.; Ishii, I.

    1996-01-01

    Superconducting power generators are being developed in Japan, as a part of a R and D program on energy technology, the New Sunshine Project. In this development, national laboratories are taking a role of fundamental studies to contribute to the R and D being carried out mainly by the manufacturers involved in a research association, Super-GM. Stabilities of magnets in a high gravitational field up to 2,000 G are discussed, based upon the experimental results of forced quench tests in a set of rotating magnets, in order to establish the stability design criterion of field windings of superconducting generators. Relations of propagation velocities, recovery currents, minimum quench energy and heat transfer characteristics are studied, a good agreement between the experimental results and a theory confirmed the improvement of magnet stability in a high gravitational field because of the enhanced heat transfer characteristics

  7. Study on optimization design of superconducting magnet for magnetic force assisted drug delivery system

    International Nuclear Information System (INIS)

    Fukui, S.; Abe, R.; Ogawa, J.; Oka, T.; Yamaguchi, M.; Sato, T.; Imaizumi, H.

    2007-01-01

    Analytical study on the design of the superconducting magnet for the magnetic force assisted drug delivery system is presented in this paper. The necessary magnetic field condition to reside the magnetic drug particle in the blood vessels is determined by analyzing the particle motion in the blood vessel. The design procedure of the superconducting magnet for the M-DDS is presented and some case studies are conducted. The analytical results show that the superconducting magnet to satisfy the magnetic field conduction for the M-DDS is practically feasible

  8. Novel axolotl cardiac function analysis method using magnetic resonance imaging

    NARCIS (Netherlands)

    Sanches, Pedro Gomes; Op 't Veld, Roel C.; de Graaf, Wolter; Strijkers, Gustav J.; Grüll, Holger

    2017-01-01

    The salamander axolotl is capable of complete regeneration of amputated heart tissue. However, non-invasive imaging tools for assessing its cardiac function were so far not employed. In this study, cardiac magnetic resonance imaging is introduced as a non-invasive technique to image heart function

  9. Novel axolotl cardiac function analysis method using magnetic resonance imaging

    NARCIS (Netherlands)

    Sanches, P.G.; Op ‘t Veld, R.C.; de Graaf, W.; Strijkers, G.J.; Grüll, H.

    2017-01-01

    The salamander axolotl is capable of complete regeneration of amputated heart tissue. However, non-invasive imaging tools for assessing its cardiac function were so far not employed. In this study, cardiac magnetic resonance imaging is introduced as a noninvasive technique to image heart function of

  10. Novel method for detecting weak magnetic fields at low frequencies

    Science.gov (United States)

    González-Martínez, S.; Castillo-Torres, J.; Mendoza-Santos, J. C.; Zamorano-Ulloa, R.

    2005-06-01

    A low-level-intensity magnetic field detection system has been designed and developed based on the amplification-selection process of signals. This configuration is also very sensitive to magnetic field changes produced by harmonic-like electrical currents transported in finite-length wires. Experimental and theoretical results of magnetic fields detection as low as 10-9T at 120Hz are also presented with an accuracy of around 13%. The assembled equipment is designed to measure an electromotive force induced in a free-magnetic-core coil in order to recover signals which are previously selected, despite the fact that their intensities are much lower than the environment electromagnetic radiation. The prototype has a signal-to-noise ratio of 60dB. This system also presents the advantage for using it as a portable unit of measurement. The concept and prototype may be applied, for example, as a nondestructive method to analyze any corrosion formation in metallic oil pipelines which are subjected to cathodic protection.

  11. MAGNETIC TWEEZERS FOR THE STUDY OF DNA TRACKING MOTORS

    Science.gov (United States)

    Manosas, Maria; Meglio, Adrien; Spiering, Michelle M.; Ding, Fangyuan; Benkovic, Stephen J.; Barre, François-Xavier; Saleh, Omar A.; Allemand, Jean François; Bensimon, David; Croquette, Vincent

    2011-01-01

    Single-molecule manipulation methods have opened a new vista on the study of molecular motors. Here we describe the use of magnetic traps for the investigation of the mechanism of DNA based motors, in particular helicases and translocases. PMID:20627163

  12. Magnetic separation as a method to assist mineralogical characterization of rocks by X-ray diffraction

    International Nuclear Information System (INIS)

    Silva, Amanda Luzia da; Oliveira, Arno Heeren de; Fernandes, Maria Lourdes Souza

    2013-01-01

    The X-ray diffraction (XRD) corresponds to one of the main techniques for characterization of structures in crystalline materials widely used in the identification of minerals in samples of geological materials such as rocks. However, the large number of mineral phases present in a rock sample can generate excess peaks in the diffractogram, and it can promote overlapping peaks and induce erroneous identification. The purpose of this study was to perform magnetic separation of minerals from rock samples in order to enable the identification of the minerals by XRD. For this magnetic separation, two samples of rock were selected: a sample of high silica content and a sample with low silica content. The magnetic separation of minerals from each sample was performed using the magnetic separator isodynamic Frantz. Posteriorly, the fractions obtained in magnetic separations were analyzed by XRD. In the sample with high silica content, it was obtained a fraction where was identified the accessory mineral epidote, which had not been identified in the total sample diffractogram. In the sample with low silica content, the magnetic separation into several mineral fractions made possible to obtain diffraction patterns with fewer peaks and peaks with higher relative intensities, which allowed its mineralogical characterization. The results showed that the mineral separation by the magnetic separator Frantz made the identification of accessory minerals by XRD and the characterization of samples which have many mineral phases possible, which proves that magnetic separation by Frantz is a method which can assist analyses by XRD. (author)

  13. Magnetic separation as a method to assist mineralogical characterization of rocks by X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Amanda Luzia da; Oliveira, Arno Heeren de; Fernandes, Maria Lourdes Souza, E-mail: amanda@igc.ufmg.br, E-mail: heeren@nuclear.ufmg.br, E-mail: amanda@igc.ufmg.br, E-mail: lurdesfernandes@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horionte, MG (Brazil)

    2013-07-01

    The X-ray diffraction (XRD) corresponds to one of the main techniques for characterization of structures in crystalline materials widely used in the identification of minerals in samples of geological materials such as rocks. However, the large number of mineral phases present in a rock sample can generate excess peaks in the diffractogram, and it can promote overlapping peaks and induce erroneous identification. The purpose of this study was to perform magnetic separation of minerals from rock samples in order to enable the identification of the minerals by XRD. For this magnetic separation, two samples of rock were selected: a sample of high silica content and a sample with low silica content. The magnetic separation of minerals from each sample was performed using the magnetic separator isodynamic Frantz. Posteriorly, the fractions obtained in magnetic separations were analyzed by XRD. In the sample with high silica content, it was obtained a fraction where was identified the accessory mineral epidote, which had not been identified in the total sample diffractogram. In the sample with low silica content, the magnetic separation into several mineral fractions made possible to obtain diffraction patterns with fewer peaks and peaks with higher relative intensities, which allowed its mineralogical characterization. The results showed that the mineral separation by the magnetic separator Frantz made the identification of accessory minerals by XRD and the characterization of samples which have many mineral phases possible, which proves that magnetic separation by Frantz is a method which can assist analyses by XRD. (author)

  14. Comparison among T1-weighted magnetic resonance imaging, modified dixon method, and magnetic resonance spectroscopy in measuring bone marrow fat.

    Science.gov (United States)

    Shen, Wei; Gong, Xiuqun; Weiss, Jessica; Jin, Ye

    2013-01-01

    An increasing number of studies are utilizing different magnetic resonance (MR) methods to quantify bone marrow fat due to its potential role in osteoporosis. Our aim is to compare the measurements of bone marrow fat among T1-weighted magnetic resonance imaging (MRI), modified Dixon method (also called fat fraction MRI (FFMRI)), and magnetic resonance spectroscopy (MRS). Contiguous MRI scans were acquired in 27 Caucasian postmenopausal women with a modified Dixon method (i.e., FFMRI). Bone marrow adipose tissue (BMAT) of T1-weighted MRI and bone marrow fat fraction of the L3 vertebra and femoral necks were quantified using SliceOmatic and Matlab. MRS was also acquired at the L3 vertebra. Correlation among the three MR methods measured bone marrow fat fraction and BMAT ranges from 0.78 to 0.88 (P BMAT measured by T1-weighted MRI and bone marrow fat fraction measured by modified FFMRI is 0.86 (P < 0.001) in femoral necks. There are good correlations among T1-weighted MRI, FFMRI, and MRS for bone marrow fat quantification. The inhomogeneous distribution of bone marrow fat, the threshold segmentation of the T1-weighted MRI, and the ambiguity of the FFMRI may partially explain the difference among the three methods.

  15. Preliminary studies on a magneto-optical procedure for aligning RHIC magnets

    International Nuclear Information System (INIS)

    Goldman, M.A.; Sikora, R.E.; Shea, T.J.

    1993-01-01

    Colloid dispersions of magnetite were used at SLAC and KEK to locate multipole magnet centers. The authors study here possible adaption of this method, to align RHIC magnets. A procedure for locating magnetic centers with respect to external fiducial markers, using electronic coordinate determination and digital TV image processing is described

  16. Apparatus and method for magnetically unloading a rotor bearing

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Seth Robert

    2018-02-13

    An apparatus and method for unloading a rotor bearing is described. The apparatus includes an electromagnet for levitating the rotor. In one embodiment, a sensor of the magnetic field near the electromagnet is used to control the current to levitate the rotor. In another embodiment, a method is provided that includes rotating the rotor, increasing the current to levitate the rotor and decrease the gap between electromagnet and rotor, and then reducing the current to levitate the rotor with a minimal amount of electric power to the electromagnet.

  17. Nuclear magnetic resonance studies of metabolic regulation

    International Nuclear Information System (INIS)

    Sillerud, L.O.; Han, C.H.; Whaley, T.W.

    1983-01-01

    Nuclear magnetic resonance (NMR) techniques for the detection of the metabolic transformations of biological compounds labeled with stable isotopes, particularly carbon-13 have been explored. We have studied adipose tissue in the intact rat, the exteriorized epididymal fat pad, and the isolated adipocyte. Triacylglycerol metabolism in adipose tissue is regulated by lipogenic factors (insulin, corticosterone, thyroxine, and growth hormone) and lipolytic factors (glucagon and catecholamines). The synthesis of triglyceride from 5.5 mM glucose was stimulated by about 4-fold by 10 nM insulin. Triglyceride synthesis from glucose in the presence of insulin occurred at a rate of 330 nmol/hr/10 6 cells. Since the NMR signals from free and esterified fatty acids and glycerol are distinct, we could directly measure the rate of hormone-stimulated lipolysis. Epinephrine (10 μM) gave a lipolytic rate of 0.30 μmol/hr/10 6 cells as monitored by free-glycerol appearance in the medium. 13 C NMR provides a superior method for the measurement of triglyceride metabolism since it directly measures the changes in the substrates and products in situ

  18. A preliminary magnetic study of Sawa lake sediments, Southern Iraq

    Science.gov (United States)

    Ameen, Nawrass

    2016-04-01

    A preliminary magnetic study combined with chemical analyses was carried out in Sawa Lake in Al-Muthanna province, southern Iraq, about 22 km south west of Samawa city (31°18'48.80"N, 45°0'25.25"E). The lake is about 4.74 km length, 1.75 km width and 5.5 m height, it is surrounded by a salt rim which is higher than the lake water by about 2.8 m and sea water by about 18.5 m (Naqash et al., 1977 in Hassan, 2007). The lake is an elongated closed basin with no surface water available to it, it may be fed by groundwater of the Euphrates and Dammam aquifers through system of joints and cracks. This study aims to investigate the concentrations of selected heavy metals as pollutants and magnetic susceptibility (MS) and other magnetic properties of sediment samples from fifty sites collected from the bottom of the lake, the study area lies in an industrial area. The results show spatial variations of MS with mean value of about 4.58 x 10-8 m3 kg-1. Scanning electron microscopy and magnetic mineralogy parameters indicate the dominance of soft magnetic phase like magnetite and presence of hard magnetic phase like hematite. Spatial variations of MS combined with the concentrations of heavy metals suggests the efficiency of magnetic methods as effective, inexpensive and non-time consuming method to outlining the heavy metal pollution. References: Hassan W.F., 2007. The Physio-chemical characteristic of Sawa lake water in Samawa city-Iraq. Marine Mesopotamica, 22(2), 167-179.

  19. Force-free magnetic fields - The magneto-frictional method

    Science.gov (United States)

    Yang, W. H.; Sturrock, P. A.; Antiochos, S. K.

    1986-01-01

    The problem under discussion is that of calculating magnetic field configurations in which the Lorentz force j x B is everywhere zero, subject to specified boundary conditions. We choose to represent the magnetic field in terms of Clebsch variables in the form B = grad alpha x grad beta. These variables are constant on any field line so that each field line is labeled by the corresponding values of alpha and beta. When the field is described in this way, the most appropriate choice of boundary conditions is to specify the values of alpha and beta on the bounding surface. We show that such field configurations may be calculated by a magneto-frictional method. We imagine that the field lines move through a stationary medium, and that each element of magnetic field is subject to a frictional force parallel to and opposing the velocity of the field line. This concept leads to an iteration procedure for modifying the variables alpha and beta, that tends asymptotically towards the force-free state. We apply the method first to a simple problem in two rectangular dimensions, and then to a problem of cylindrical symmetry that was previously discussed by Barnes and Sturrock (1972). In one important respect, our new results differ from the earlier results of Barnes and Sturrock, and we conclude that the earlier article was in error.

  20. Magnetic Barkhausen noise measurement by resonant coil method

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-15

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

  1. Magnetic field adjustment structure and method for a tapered wiggler

    Science.gov (United States)

    Halbach, Klaus

    1988-01-01

    An improved method and structure is disclosed for adjusting the magnetic field generated by a group of electromagnet poles spaced along the path of a charged particle beam to compensate for energy losses in the charged particles which comprises providing more than one winding on at least some of the electromagnet poles; connecting one respective winding on each of several consecutive adjacent electromagnet poles to a first power supply, and the other respective winding on the electromagnet pole to a different power supply in staggered order; and independently adjusting one power supply to independently vary the current in one winding on each electromagnet pole in a group whereby the magnetic field strength of each of a group of electromagnet poles may be changed in smaller increments.

  2. The Magnetic Reconnection Code: Center for Magnetic Reconnection Studies

    Energy Technology Data Exchange (ETDEWEB)

    Amitava Bhattacharjee

    2007-04-20

    Understanding magnetic reconnection is one of the principal challenges in plasma physics. Reconnection is a process by which magnetic fields reconfigure themselves, releasing energy that can be converted to particle energies and bulk flows. Thanks to the availability of sophisticated diagnostics in fusion and laboratory experiments, in situ probing of magnetospheric and solar wind plasmas, and X-ray emission measurements from solar and stellar plasmas, theoretical models of magnetic reconnection can now be constrained by stringent observational tests. The members of the CMRS comprise an interdisciplinary group drawn from applied mathematics, astrophysics, computer science, fluid dynamics, plasma physics, and space science communities.

  3. [Computer modelling of electroconvulsive treatment and transcranial magnetic stimulation--an explanation of poor efficacy of the magnetic method].

    Science.gov (United States)

    Zyss, Tomasz; Krawczyk, Andrzej; Zieba, Andrzej; Dudek, Dominika; Hese, Robert T; Drzymała, Paweł; Wiak, Sławomir; Sawicki, Bartosz; Starzyński, Jacek; Szmurło, Robert; Wincenciak, Stanisław

    2010-01-01

    With help of informatics technology it is possible to simulate various physiological processes in virtual models of biological structures. In a created realistic model of the human head we made some comparative investigations over physical phenomena accompanying the electroconvulsive treatment ECT and transcranial magnetic stimulation TMS--two methods with confirmed (ECT) or presumable (TMS) antidepressant efficacy. The present investigations are a continuation of the earlier conducted study in the simple spherical model of the head. Investigations confirmed, that magnetic stimulation TMS generates a considerably weaker current flow in the brain than it is present in electroconvulsive technique. Applying of such weak stimulation in modus,,at haphazard", i.e. on the brain area which does not need to be metabolically disturbed in this patient--cannot cause an antidepressant effect at all. The results of the investigations explain not only the safety of the magnetic method, but the weak effectiveness of this method. The authors propose some methods for improvement of TMS efficacy.

  4. Integration of Magnetic and Geotechnical methods for Shallow Subsurface Soil Characterization at Sungai Batu, Kedah, Malaysia

    Science.gov (United States)

    Samuel, Y. M.; Saad, R.; Muztaza, N. M.; Saidin, M. M.; Muhammad, S. B.

    2018-04-01

    Magnetic and geotechnical methods were used for shallow subsurface soil characterization at Sungai Batu, Kedah, (Malaysia). Ground magnetic data were collected along a survey line of length 160 m long at 2 m constant station spacing, while soil drilling using hand auger was conducted at 21 m on the survey line using 0.2 m sampling interval drilled to a depth of 5 m. Result from the processed magnetic profile data shows distribution of magnetic residuals in the range of -4.55 to 1.61 nT, with magnetic low (-4.55 nT to -0.058 nT) and were identified at distances 4 m, 10 to 16 m, 20 to 26 m, 58 m, 82 m, 104 to 106 m, 118 m, and 124 to 140 m. The magnetic lows are attributes of sediments. The result from the soil drilling shows sticky samples with variable sizes, greyish to brownish / reddish in colour, and some of the samples show the presence of shiny and black spots. The characteristics of the samples suggest the soil as a by-product of completely weathered rock; weak with high water content and classified as Grade V soil. The study concludes; integration of geophysical and geotechnical methods aided in characterizing the subsurface soil at Sungai Batu. The result was correlated with previous studies and confirms the importance of integrated approach in minimising ambiguity in interpretation.

  5. Neutron scattering studies of modulated magnetic structures

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard Soerensen, Steen

    1999-08-01

    This report describes investigations of the magnetic systems DyFe{sub 4}Al{sub 8} and MnSi by neutron scattering and in the former case also by X-ray magnetic resonant scattering. The report is divided into three parts: An introduction to the technique of neutron scattering with special emphasis on the relation between the scattering cross section and the correlations between the scattering entities of the sample. The theoretical framework of neutron scattering experiments using polarized beam technique is outlined. The second part describes neutron and X-ray scattering investigation of the magnetic structures of DyFe{sub 4}Al{sub 8}. The Fe sublattice of the compound order at 180 K in a cycloidal structure in the basal plane of the bct crystal structure. At 25 K the ordering of the Dy sublattice shows up. By the element specific technique of X-ray resonant magnetic scattering, the basal plane cycloidal structure was also found for the Dy sublattice. The work also includes neutron scattering studies of DyFe{sub 4}Al{sub 8} in magnetic fields up to 5 T applied along a <110> direction. The modulated structure at the Dy sublattice is quenched by a field lower than 1 T, whereas modulation is present at the Fe sublattice even when the 5 T field is applied. In the third part of the report, results from three small angle neutron experiments on MnSi are presented. At ambient pressure, a MnSi is known to form a helical spin density wave at temperature below 29 K. The application of 4.5 kbar pressure intended as hydrostatic decreased the Neel temperature to 25 K and changed the orientation of the modulation vector. To understand this reorientation within the current theoretical framework, anisotropic deformation of the sample crystal must be present. The development of magnetic critical scattering with an isotropic distribution of intensity has been studied at a level of detail higher than that of work found in the literature. Finally the potential of a novel polarization

  6. Evaluation of magnetic properties of NI-ZN ferrites obtained by different synthesis methods

    International Nuclear Information System (INIS)

    Simoes, A.N.; Neiva, L.S.; Simoes, V.N.; Gama, L.; Gomes Filho, A.C.; Oliveira, J.B.L.

    2012-01-01

    Ceramic oxides that exhibit ferromagnetic behavior represent important commercial products for the electronics industry and are commonly known as ferrites. The Ni-Zn ferrites are considered to be one of the most versatile and soft due to its high electrical resistivity and low eddy current losses. Thus, this study aims to evaluate the magnetic properties of Ni-Zn ferrite obtained by the Pechini and combustion reaction. After synthesis the powders were characterized by XRD, SEM, BET and magnetic measurements. The results showed that for both methods of synthesis used was the formation of the spinel phase of Ni-Zn ferrite. The micrographs show that the powders obtained by both methods have regular shapes and spherical. Were determined by BET surface area is 26 m 2 /g by the Pechini and 13 m 2 /g by combustion. And the samples synthesized by Pechini method obtained the best magnetic characteristics (author)

  7. A new method to determine magnetic properties of the unsaturated-magnetized rotor of a novel gyro

    Science.gov (United States)

    Li, Hai; Liu, Xiaowei; Dong, Changchun; Zhang, Haifeng

    2016-06-01

    A new method is proposed to determine magnetic properties of the unsaturated-magnetized, small and irregular shaped rotor of a novel gyro. The method is based on finite-element analysis and the measurements of the magnetic flux density distribution, determining magnetic parameters by comparing the magnetic flux intensity distribution differences between the modeling results under different parameters and the measured ones. Experiment on a N30 Grade NdFeB magnet shows that its residual magnetic flux density is 1.10±0.01 T, and coercive field strength is 801±3 kA/m, which are consistent with the given parameters of the material. The method was applied to determine the magnetic properties of the rotor of the gyro, and the magnetic properties acquired were used to predict the open-loop gyro precession frequency. The predicted precession frequency should be larger than 12.9 Hz, which is close to the experimental result 13.5 Hz. The result proves that the method is accurate in estimating the magnetic properties of the rotor of the gyro.

  8. Electronic Structure Calculation of Permanent Magnets using the KKR Green's Function Method

    Science.gov (United States)

    Doi, Shotaro; Akai, Hisazumi

    2014-03-01

    Electronic structure and magnetic properties of permanent magnetic materials, especially Nd2Fe14B, are investigated theoretically using the KKR Green's function method. Important physical quantities in magnetism, such as magnetic moment, Curie temperature, and anisotropy constant, which are obtained from electronics structure calculations in both cases of atomic-sphere-approximation and full-potential treatment, are compared with past band structure calculations and experiments. The site preference of heavy rare-earth impurities are also evaluated through the calculation of formation energy with the use of coherent potential approximations. Further, the development of electronic structure calculation code using the screened KKR for large super-cells, which is aimed at studying the electronic structure of realistic microstructures (e.g. grain boundary phase), is introduced with some test calculations.

  9. Practical assessment of magnetic methods for corrosion detection in an adjacent precast, prestressed concrete box-beam bridge

    Science.gov (United States)

    Fernandes, Bertrand; Titus, Michael; Nims, Douglas Karl; Ghorbanpoor, Al; Devabhaktuni, Vijay Kumar

    2013-06-01

    Magnetic methods are progressing in the detection of corrosion in prestressing strands in adjacent precast, prestressed concrete box-beam bridges. This study is the first field trial of magnetic strand defect detection systems on an adjacent box-beam bridge. A bridge in Fayette County, Ohio, which was scheduled for demolition, was inspected. Damage to prestressed box-beams is often due to corrosion of the prestressing strands. The corroded strands show discontinuities and a reduced cross-sectional area. These changes, due to corrosion, are reflected in the magnetic signatures of the prestressing steel. Corrosion in the prestressing steel was detected using two magnetic methods, namely the 'magnetic flux leakage' (MFL) and the 'induced magnetic field'. The purpose of these tests was to demonstrate the ability of the magnetic methods to detect hidden corrosion in box-beams in the field and tackle the logistic problem of inspecting box-beams from the bottom. The inspections were validated by dissecting the bottom of the box-beams after the inspections. The results showed that the MFL method can detect hidden corrosion and strand breaks. Both magnetic field methods were also able to estimate corrosion by detecting the effective cross-sectional area of the strand in sections of the beams. Thus, it was shown that the magnetic methods can be used to predict hidden corrosion in prestressing strands of box-beams.

  10. An efficient simulation method of a cyclotron sector-focusing magnet using 2D Poisson code

    Energy Technology Data Exchange (ETDEWEB)

    Gad Elmowla, Khaled Mohamed M; Chai, Jong Seo, E-mail: jschai@skku.edu; Yeon, Yeong H; Kim, Sangbum; Ghergherehchi, Mitra

    2016-10-01

    In this paper we discuss design simulations of a spiral magnet using 2D Poisson code. The Independent Layers Method (ILM) is a new technique that was developed to enable the use of two-dimensional simulation code to calculate a non-symmetric 3-dimensional magnetic field. In ILM, the magnet pole is divided into successive independent layers, and the hill and valley shape around the azimuthal direction is implemented using a reference magnet. The normalization of the magnetic field in the reference magnet produces a profile that can be multiplied by the maximum magnetic field in the hill magnet, which is a dipole magnet made of the hills at the same radius. Both magnets are then calculated using the 2D Poisson SUPERFISH code. Then a fully three-dimensional magnetic field is produced using TOSCA for the original spiral magnet, and the comparison of the 2D and 3D results shows a good agreement between both.

  11. Study of the magnetic interaction in nanocrystalline Pr–Fe–Co–Nb–B permanent magnets

    International Nuclear Information System (INIS)

    Dospial, M.; Plusa, D.; Ślusarek, B.

    2012-01-01

    The magnetic properties of an isotropic, epoxy resin bonded magnets made from Pr–Fe–Co–Nb–B powder were investigated. The magnetization reversal process and magnetic parameters were examined by measurements of the initial magnetization curve, major and minor hysteresis loops and sets of recoil curves. From the initial magnetization curve and the field dependencies of the reversible and irreversible magnetization components derived from the recoil loops it was found that the magnetization reversal process is the combination of the nucleation of reversed domains and pinning of domain walls at the grain boundaries and the reversible rotation of magnetization vector in single domain grains. The interactions between grains were studied by means of δM plots. The nonlinear behavior of δM curve approve that the short range intergrain exchange coupling interactions are dominant in a field up to the sample coercivity. The interaction domains and fine magnetic structure were revealed as the evidence of exchange coupling between soft α-Fe and hard magnetic Nd 2 Fe 14 B grains. - Highlights: ► Coercivity of the Pr–Fe–Co–Nb–B magnet is determined by the pinning of domain walls at the grain boundaries. ► Rotation of magnetization vector and domain walls bowing also give the contribution to the initial and demagnetization process. ► δM behavior shows that the dominant interaction is the short range exchange one among soft magnetic α-Fe and hard magnetic Pr 2 Fe 14 B grains.

  12. Magnetic methods for nondestructive control of residual stresses

    International Nuclear Information System (INIS)

    Suarez, J.C.; Cruz, C.; Alarcon, H.; Ledo, J.L.

    1993-01-01

    In this work, magnetic methods being used at present to determine the TR in ferromagnetic materials are introduced, comparing them with similar technic, based in the application of Strain gauges, DRX and ultrasonic. The technical requirements needed to perform TR measurements, based on the magnetoelastic effect (MEA) and the measuring of Barkhausen noise (BNA) are analyzed. Finally, it is showed the development obtained by CEADEN in the use of these two techniques and the perspectives of their introduction in the country, using national equipment

  13. A New Method for Coronal Magnetic Field Reconstruction

    Science.gov (United States)

    Yi, Sibaek; Choe, Gwang-Son; Cho, Kyung-Suk; Kim, Kap-Sung

    2017-08-01

    A precise way of coronal magnetic field reconstruction (extrapolation) is an indispensable tool for understanding of various solar activities. A variety of reconstruction codes have been developed so far and are available to researchers nowadays, but they more or less bear this and that shortcoming. In this paper, a new efficient method for coronal magnetic field reconstruction is presented. The method imposes only the normal components of magnetic field and current density at the bottom boundary to avoid the overspecification of the reconstruction problem, and employs vector potentials to guarantee the divergence-freeness. In our method, the normal component of current density is imposed, not by adjusting the tangential components of A, but by adjusting its normal component. This allows us to avoid a possible numerical instability that on and off arises in codes using A. In real reconstruction problems, the information for the lateral and top boundaries is absent. The arbitrariness of the boundary conditions imposed there as well as various preprocessing brings about the diversity of resulting solutions. We impose the source surface condition at the top boundary to accommodate flux imbalance, which always shows up in magnetograms. To enhance the convergence rate, we equip our code with a gradient-method type accelerator. Our code is tested on two analytical force-free solutions. When the solution is given only at the bottom boundary, our result surpasses competitors in most figures of merits devised by Schrijver et al. (2006). We have also applied our code to a real active region NOAA 11974, in which two M-class flares and a halo CME took place. The EUV observation shows a sudden appearance of an erupting loop before the first flare. Our numerical solutions show that two entwining flux tubes exist before the flare and their shackling is released after the CME with one of them opened up. We suggest that the erupting loop is created by magnetic reconnection between

  14. Magnetic properties of magnetic Co1-xMgxFe2O4 spinel by HTSE method

    International Nuclear Information System (INIS)

    Hamedoun, M.; Benyoussef, A.; Bousmina, M.

    2011-01-01

    Magnetic properties and exchange-coupling interactions of diluted magnetic spinels A 1-x A' x B 2 X 4 , where A and B are magnetic ions, namely Co 1-x Mg x Fe 2 O 4 , were investigated using the high-temperature series expansion method (HTSE) and the distribution method of magnetic cations in the range 0≤x≤1. The magnetic phase diagram and transition temperature versus dilution x were determined using the Pade approximants method along with HTSE. The critical exponent associated with the magnetic susceptibility γ was then deduced. The obtained results are in good agreement with experimental results and critical exponent values are consistent with those suggested by the universality hypothesis.

  15. Self-consistent studies of magnetic thin film Ni (001)

    International Nuclear Information System (INIS)

    Wang, C.S.; Freeman, A.J.

    1979-01-01

    Advances in experimental methods for studying surface phenomena have provided the stimulus to develop theoretical methods capable of interpreting this wealth of new information. Of particular interest have been the relative roles of bulk and surface contributions since in several important cases agreement between experiment and bulk self-consistent (SC) calculations within the local spin density functional formalism (LSDF) is lacking. We discuss our recent extension of the (LSDF) approach to the study of thin films (slabs) and the role of surface effects on magnetic properties. Results are described for Ni (001) films using our new SC numerical basis set LCAO method. Self-consistency within the superposition of overlapping spherical atomic charge density model is obtained iteratively with the atomic configuration as the adjustable parameter. Results are presented for the electronic charge densities and local density of states. The origin and role of (magnetic) surface states is discussed by comparison with results of earlier bulk calculations

  16. Method for forming permanent magnets with different polarities for use in microelectromechanical devices

    Science.gov (United States)

    Roesler, Alexander W [Tijeras, NM; Christenson, Todd R [Albuquerque, NM

    2007-04-24

    Methods are provided for forming a plurality of permanent magnets with two different north-south magnetic pole alignments for use in microelectromechanical (MEM) devices. These methods are based on initially magnetizing the permanent magnets all in the same direction, and then utilizing a combination of heating and a magnetic field to switch the polarity of a portion of the permanent magnets while not switching the remaining permanent magnets. The permanent magnets, in some instances, can all have the same rare-earth composition (e.g. NdFeB) or can be formed of two different rare-earth materials (e.g. NdFeB and SmCo). The methods can be used to form a plurality of permanent magnets side-by-side on or within a substrate with an alternating polarity, or to form a two-dimensional array of permanent magnets in which the polarity of every other row of the array is alternated.

  17. Method for increasing nuclear magnetic resonance signals in living biological tissue

    International Nuclear Information System (INIS)

    Krongrad, A.

    1995-01-01

    A method of enhancing a magnetic resonance comprising the steps of administering a quantity of a selected magnetic isotope to a living biological tissue at a concentration greater than the naturally occurring concentration of such isotope and detecting magnetic resonance signal from the administered magnetic isotope in the living biological tissue. (author)

  18. Computational methods for analyzing the transmission characteristics of a beta particle magnetic analysis system

    Science.gov (United States)

    Singh, J. J.

    1979-01-01

    Computational methods were developed to study the trajectories of beta particles (positrons) through a magnetic analysis system as a function of the spatial distribution of the radionuclides in the beta source, size and shape of the source collimator, and the strength of the analyzer magnetic field. On the basis of these methods, the particle flux, their energy spectrum, and source-to-target transit times have been calculated for Na-22 positrons as a function of the analyzer magnetic field and the size and location of the target. These data are in studies requiring parallel beams of positrons of uniform energy such as measurement of the moisture distribution in composite materials. Computer programs for obtaining various trajectories are included.

  19. Magnetic force microscopy study on wide adjacent track erasure in perpendicular magnetic write heads

    Science.gov (United States)

    Ruksasakchai, P.; Saengkaew, K.; Cheowanish, I.; Damrongsak, B.

    2017-09-01

    We used a phase-contrast magnetic force microscopy (MFM) to observe and analyze the failure of magnetic write heads due to the WATEr problem, which limits the off-track performance. During MFM imaging, the magnetic write head was energized by a DC current. The induced out-of-plane magnetic field was then detected by scanning a MFM probe across the surface of the magnetic write head. MFM images were then mapped with WATEr measured results from a spin stand method. Results showed that WATEr effect can be generated by several factors, i.e. the structure of magnetic domains and walls from material discontinuities and the magnetic field leakage at different locations on magnetic write heads. Understanding WATEr mechanisms is useful for design and process development engineers.

  20. Optimization study on the magnetic field of superconducting Halbach Array magnet

    Science.gov (United States)

    Shen, Boyang; Geng, Jianzhao; Li, Chao; Zhang, Xiuchang; Fu, Lin; Zhang, Heng; Ma, Jun; Coombs, T. A.

    2017-07-01

    This paper presents the optimization on the strength and homogeneity of magnetic field from superconducting Halbach Array magnet. Conventional Halbach Array uses a special arrangement of permanent magnets which can generate homogeneous magnetic field. Superconducting Halbach Array utilizes High Temperature Superconductor (HTS) to construct an electromagnet to work below its critical temperature, which performs equivalently to the permanent magnet based Halbach Array. The simulations of superconducting Halbach Array were carried out using H-formulation based on B-dependent critical current density and bulk approximation, with the FEM platform COMSOL Multiphysics. The optimization focused on the coils' location, as well as the geometry and numbers of coils on the premise of maintaining the total amount of superconductor. Results show Halbach Array configuration based superconducting magnet is able to generate the magnetic field with intensity over 1 Tesla and improved homogeneity using proper optimization methods. Mathematical relation of these optimization parameters with the intensity and homogeneity of magnetic field was developed.

  1. Gilbert's De Magnete: An early study of magnetism and electricity

    Science.gov (United States)

    Malin, Stuart; Barraclough, David

    Four hundred years might seem an excessively long time to wait for a book review, but there are reasons why a prompt review would have been difficult. Not only is De Magnete written in Latin, but it is also in the form of a scientific textbook. The language problem was overcome by Paul Fleury Mottelay and Silvanus P. Thompson, who translated the book into English in 1893 and 1900, respectively. The latter was published in connection with a beautiful tercentenary limited edition by the Chiswick Press that retains much of the flavor and appearance of the original. But the notion of a scientific textbook was unfamiliar when De Magnete first appeared in 1600. Certainly, scientific subjects and even geomagnetism had been written about (for example, by Petrus Peregrinus in his Epistola De Magnete, 1269), but as reports of equipment and phenomena rather than as in-depth investigations of a subject with experimental evidence and interpretation.

  2. Structure of transformer oil-based magnetic fluids studied using acoustic spectroscopy

    International Nuclear Information System (INIS)

    Kúdelčík, Jozef; Bury, Peter; Drga, Jozef; Kopčanský, Peter; Závišová, Vlasta; Timko, Milan

    2013-01-01

    The structural changes in transformer oil-based magnetic fluids upon the effect of an external magnetic field and temperature were studied by acoustic spectroscopy. The attenuation of acoustic wave was measured as a function of the magnetic field in the range of 0–300 mT and in the temperature range of 15–35 °C for various magnetic nanoparticles concentrations. The effect of anisotropy of the acoustic attenuation was determined, too. The both strong influence of the magnetic field on the acoustic attenuation and its hysteresis were observed. When a magnetic field is increased, the interaction between the external magnetic field and the magnetic moments of the nanoparticles occurs, leading to the aggregation of magnetic nanoparticles and following clusters formation. However, the temperature of magnetic fluids also has very important influence on the structural changes because of the mechanism of thermal motion that acts against the cluster creation. The observed influences of both magnetic field and temperature on the investigated magnetic fluid structure are discussed. - Highlights: ► Structural changes in transformer oil-based magnetic fluids were investigated. ► The acoustic spectroscopy as the method of investigation was used. ► The influence of magnetic field on the structural was studied. ► The influence of temperatures on the structures was investigated, too. ► The influence of external conditions on the structure of MF is interpreted.

  3. Structure of transformer oil-based magnetic fluids studied using acoustic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kudelcik, Jozef, E-mail: kudelcik@fyzika.uniza.sk [Department of Physics, University of Zilina, Univerzitna 1, 010 01 Zilina (Slovakia); Bury, Peter; Drga, Jozef [Department of Physics, University of Zilina, Univerzitna 1, 010 01 Zilina (Slovakia); Kopcansky, Peter; Zavisova, Vlasta; Timko, Milan [Department of Magnetism, IEP SAS, Watsonova 47, 040 01 Kosice (Slovakia)

    2013-01-15

    The structural changes in transformer oil-based magnetic fluids upon the effect of an external magnetic field and temperature were studied by acoustic spectroscopy. The attenuation of acoustic wave was measured as a function of the magnetic field in the range of 0-300 mT and in the temperature range of 15-35 Degree-Sign C for various magnetic nanoparticles concentrations. The effect of anisotropy of the acoustic attenuation was determined, too. The both strong influence of the magnetic field on the acoustic attenuation and its hysteresis were observed. When a magnetic field is increased, the interaction between the external magnetic field and the magnetic moments of the nanoparticles occurs, leading to the aggregation of magnetic nanoparticles and following clusters formation. However, the temperature of magnetic fluids also has very important influence on the structural changes because of the mechanism of thermal motion that acts against the cluster creation. The observed influences of both magnetic field and temperature on the investigated magnetic fluid structure are discussed. - Highlights: Black-Right-Pointing-Pointer Structural changes in transformer oil-based magnetic fluids were investigated. Black-Right-Pointing-Pointer The acoustic spectroscopy as the method of investigation was used. Black-Right-Pointing-Pointer The influence of magnetic field on the structural was studied. Black-Right-Pointing-Pointer The influence of temperatures on the structures was investigated, too. Black-Right-Pointing-Pointer The influence of external conditions on the structure of MF is interpreted.

  4. Contribution to magnetic refrigeration study at liquid helium study

    International Nuclear Information System (INIS)

    Lacaze, A.

    1985-10-01

    An experimental prototype of magnetic refrigerator operates, following a Carnot cycle, with gallium gadolinium garnet, from liquid helium at 4.2 0 K. Analysis of the cyle and heat exchanges allowed to improve performance up to get more than 50% of Carnot yield at 1.8 0 K and nearly 80% at 2.1 0 K. Operation conditions of a regenerator refrigerator between 4 and 20 0 K are studied. The association of a magnetic refrigerator and a gas refrigerator is analyzed. Among different ways to realize the magnetic stage, an active regenerator cycle is chosen. An experimental device is described [fr

  5. Study of fluorine ion structural role in Al(PO3)3-MF glass by the 19F nuclear magnetic resonance method

    International Nuclear Information System (INIS)

    Gurova, N.N.; Vopilov, V.A.; Buznik, V.M.; Urusovskaya, L.N.

    1989-01-01

    Results of investigation into Al(PO 3 ) 3 -xMF glasses (M=Li, Na, K) by the 19 F NMR method are presented. Investigation supported the structural identity of glasses, containing NaF and KF. One structural position, related to fluorine atoms, coordinating lithium and aluminium ions, is observed in glasses, containing lithium fluoride. The highest mobility of fluorine atoms was revealed in glasses with lithium fluoride. Mobility of fluorine atoms is lower in glasses, containing potassium and sodium fluoride modifications. Dynamic heterogeneity in these glasses is conditioned both by distribution of frequencies of atom motion in the glass and by structural nonequivalence of positions. Fluorine atoms, coordinating cations of alkaline metals, appear to be more mobile

  6. Study on magnetic separation system using high Tc superconducting bulk magnets for water purification technique

    International Nuclear Information System (INIS)

    Oka, T; Kanayama, H; Tanaka, K; Fukui, S; Ogawa, J; Sato, T; Ooizumi, M; Yamaguchi, M; Yokoyama, K; Noto, K

    2009-01-01

    The application of superconducting bulk magnets to the magnetic separation techniques has been investigated for the Mn-bearing waste water drained from the university laboratories. The research has been conducted in comparison with the electromagnets, and the cryo-cooled superconducting solenoid magnet. The separation ratios of ferrite precipitates including Mn element in the waste slurry were estimated by means of the high gradient magnetic separation method with ferromagnetic iron filters in the water channel and open gradient magnetic separation without them. As the magnetic force acting on the particles is given by the product of a magnetization of particles and a gradient of magnetic field, and a superconducting bulk magnet shows a sharp gradient of the magnetic field on the surface, the performances of the bulk magnet system were almost equivalent to those of the superconducting solenoid magnet with wide bore with respect to the magnetic separation ratios. The separation ratios for Mn have reached over 80 % for HGMS and 10 % for OGMS under the flow rates less than 3 liter/min.

  7. Investigation of source location determination from Magsat magnetic anomalies: The Euler method approach

    Science.gov (United States)

    Ravat, Dhananjay

    1996-01-01

    The applicability of the Euler method of source location determination was investigated on several model situations pertinent to satellite-data scale situations as well as Magsat data of Europe. Our investigations enabled us to understand the end-member cases for which the Euler method will work with the present satellite magnetic data and also the cases for which the assumptions implicit in the Euler method will not be met by the present satellite magnetic data. These results have been presented in one invited lecture at the Indo-US workshop on Geomagnetism in Studies of the Earth's Interior in August 1994 in Pune, India, and at one presentation at the 21st General Assembly of the IUGG in July 1995 in Boulder, CO. A new method, called Anomaly Attenuation Rate (AAR) Method (based on the Euler method), was developed during this study. This method is scale-independent and is appropriate to locate centroids of semi-compact three dimensional sources of gravity and magnetic anomalies. The method was presented during 1996 Spring AGU meeting and a manuscript describing this method is being prepared for its submission to a high-ranking journal. The grant has resulted in 3 papers and presentations at national and international meetings and one manuscript of a paper (to be submitted shortly to a reputable journal).

  8. Study of Nonlinear MHD Tribological Squeeze Film at Generalized Magnetic Reynolds Numbers Using DTM.

    Science.gov (United States)

    Rashidi, Mohammad Mehdi; Freidoonimehr, Navid; Momoniat, Ebrahim; Rostami, Behnam

    2015-01-01

    In the current article, a combination of the differential transform method (DTM) and Padé approximation method are implemented to solve a system of nonlinear differential equations modelling the flow of a Newtonian magnetic lubricant squeeze film with magnetic induction effects incorporated. Solutions for the transformed radial and tangential momentum as well as solutions for the radial and tangential induced magnetic field conservation equations are determined. The DTM-Padé combined method is observed to demonstrate excellent convergence, stability and versatility in simulating the magnetic squeeze film problem. The effects of involved parameters, i.e. squeeze Reynolds number (N1), dimensionless axial magnetic force strength parameter (N2), dimensionless tangential magnetic force strength parameter (N3), and magnetic Reynolds number (Rem) are illustrated graphically and discussed in detail. Applications of the study include automotive magneto-rheological shock absorbers, novel aircraft landing gear systems and biological prosthetics.

  9. Study of Nonlinear MHD Tribological Squeeze Film at Generalized Magnetic Reynolds Numbers Using DTM.

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Rashidi

    Full Text Available In the current article, a combination of the differential transform method (DTM and Padé approximation method are implemented to solve a system of nonlinear differential equations modelling the flow of a Newtonian magnetic lubricant squeeze film with magnetic induction effects incorporated. Solutions for the transformed radial and tangential momentum as well as solutions for the radial and tangential induced magnetic field conservation equations are determined. The DTM-Padé combined method is observed to demonstrate excellent convergence, stability and versatility in simulating the magnetic squeeze film problem. The effects of involved parameters, i.e. squeeze Reynolds number (N1, dimensionless axial magnetic force strength parameter (N2, dimensionless tangential magnetic force strength parameter (N3, and magnetic Reynolds number (Rem are illustrated graphically and discussed in detail. Applications of the study include automotive magneto-rheological shock absorbers, novel aircraft landing gear systems and biological prosthetics.

  10. Study on magnetic field distribution in superconducting magnetic systems with account of magnetization of a superconducting winding

    International Nuclear Information System (INIS)

    Shakhtarin, V.N.; Koshurnikov, E.K.

    1977-01-01

    A method for investigating a magnetic field in a superconducting magnetic system with an allowance for magnetization of the superconducting winding material is described. To find the field, use was made of the network method for solving a nonlinear differential equation for the scalar magnetic potential of the magnetization field with adjustment of the boundary conditions by the boundary relaxation method. It was assumed that the solenoid did not pass into the normal state, and there were no flow jumps. The calculated dependences for the magnetization field of a superconducting solenoid with an inner diameter of 43 mm, an outer diameter of 138 mm, and a winding of 159 mm length are presented. The solenoid is wound with a 37-strand niobium-titanium wire. The magnetization field gradient in the area of the geometrical centre with a magnetic field strength of 43 kOe was equal to 1 Oe/cm, this meaning that within a sphere of 1 cm radius the inhomogeneity of the magnetization field was 2.5 x 10 -5

  11. Magnetic resonance studies of intercalation compounds

    International Nuclear Information System (INIS)

    Miller, G.R.

    1990-01-01

    During the last three or four years, nearly tow hundred papers have been published that used NMR or ESR spectroscopy to study compounds formed by the intercalation of molecules or ions into the van der Waals gap of a layered hast compound. The host lattices have ranged from the simple, such as graphite, to the complex, such as clay. In many cases, magnetic resonance techniques now enable one to obtain quite detailed information on even fairly complex intercalated species, on the nature of the changes in the host lattice accompanying intercalation, and on the nature of the interactions between the intercalant species and the host lattice. Magnetic resonance is used in conunction with many other techniques to obtain a fuller picture of these interesting systems, but this review will limit its focus to the use of NMR and ESR techniques. (author). 51 refs

  12. Fundamental study on gene transfer utilizing magnetic force and jet injector

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, T.; Nakagami, H.; Akiyama, Y.; Nishjima, S. [Osaka University, Osaka (Japan)

    2017-03-15

    Recently, DNA vaccination is attracting attentions as a new therapeutic method for lifestyle diseases and autoimmune diseases. However, its clinical applications are limited because a safe and efficient gene transfer method has not been established yet. In this study, a new method of gene transfer was proposed which utilizes the jet injection and the magnetic transfection. The jet injection is a method to inject medical liquid by momentary high pressure without needle. The injected liquid diffuses in the bio tissue and the endocytosis is considered to be improved by the diffusion. The magnetic transfection is a method to deliver the conjugates of plasmid DNA and magnetic particles to the desired site by external magnetic field. It is expected that jet injection of the conjugates causes slight membrane disruptions and the traction of the conjugates by magnetic field induces the efficient gene transfer. In conclusion, the possibility of improvement of the gene expression by the combination of jet injection and magnetic transfection was confirmed.

  13. Fundamental study on gene transfer utilizing magnetic force and jet injector

    International Nuclear Information System (INIS)

    Hasegawa, T.; Nakagami, H.; Akiyama, Y.; Nishjima, S.

    2017-01-01

    Recently, DNA vaccination is attracting attentions as a new therapeutic method for lifestyle diseases and autoimmune diseases. However, its clinical applications are limited because a safe and efficient gene transfer method has not been established yet. In this study, a new method of gene transfer was proposed which utilizes the jet injection and the magnetic transfection. The jet injection is a method to inject medical liquid by momentary high pressure without needle. The injected liquid diffuses in the bio tissue and the endocytosis is considered to be improved by the diffusion. The magnetic transfection is a method to deliver the conjugates of plasmid DNA and magnetic particles to the desired site by external magnetic field. It is expected that jet injection of the conjugates causes slight membrane disruptions and the traction of the conjugates by magnetic field induces the efficient gene transfer. In conclusion, the possibility of improvement of the gene expression by the combination of jet injection and magnetic transfection was confirmed

  14. Satellite to study earth's magnetic field

    Science.gov (United States)

    1979-01-01

    The Magnetic Field Satellite (Magsat) designed to measure the near earth magnetic field and crustal anomalies is briefly described. A scalar magnetometer to measure the magnitude of the earth's crustal magnetic field and a vector magnetometer to measure magnetic field direction as well as magnitude are included. The mission and its objectives are summarized along with the data collection and processing system.

  15. Electron density distribution in BaPb1−xSbxO3 superconducting oxides studied by double nuclear magnetic resonance methods

    International Nuclear Information System (INIS)

    Piskunov, Yu. V.; Ogloblichev, V. V.; Arapova, I. Yu.; Sadykov, A. V.; Gerashchenko, A. P.; Verkhovskii, S. V.

    2011-01-01

    The effect of charge disorder on the formation of an inhomogeneous state of the electron system in the conduction band in BaPb 1−x Sb x O 3 superconducting oxides is investigated experimentally by NMR methods. The NMR spectra of 17 O are measured systematically, and the contributions from 17 O atoms with different cation nearest surroundings are identified. It is found that microscopic regions with an elevated spin density of charge carriers are formed within two coordination spheres near antimony ions. Nuclei of the superconducting phase of the oxide (regions with an elevated antimony concentration) microscopically distributed over the sample are detected in compounds with x = 0.25 and 0.33. Experiments in which a double resonance signal of the spin echo of 17 O- 207 Pb and 17 O- 121 Sb are measured in the metal phase of BaPb 1−x Sb x O 3 oxides are carried out for the first time. The constants of indirect heteronuclear spin-spin 17 O- 207 Pb interaction are determined as functions of the local Knight shift 207 Ks. The estimates of the constants of the indirect interaction between the nuclei of the nearest neighbors (O-Pb and Pb-Pb atoms) and analysis of evolution of the NMR spectra of 17 O upon a change in the antimony concentration are convincing evidence in favor of the development of a microscopically inhomogeneous state of the electron system in the metal phase of BaPb 1−x Sb x O 3 oxides.

  16. Moessbauer study of the magnetic filler for suppositories

    International Nuclear Information System (INIS)

    Bykov, A.V.; Nikolaev, V.I.; Shulgin, V.I.; Diaz, C.; Kharitonov, Yu.Ya.; Cherkasova, O.G.

    1991-01-01

    Moessbauer spectroscopy methods are discussed when applied to test the properties of magnetic suppositories used in medicine. The experiments were carried out on magnetic rectal suppositories containing paramadine and fine-dispersed ferrite powder (BaO.nFe 2 O 3 ) as a magnetic filler. According to the data on the value of effective magnetic field on 57 Fe nuclei in ferrite magnetic sublattices, the stoichiometric n-number equals approximately 5.5; this value corresponds to the composition range of optimal magnetic properties. (orig.)

  17. Moessbauer study of the magnetic filler for suppositories

    Energy Technology Data Exchange (ETDEWEB)

    Bykov, A.V.; Nikolaev, V.I.; Shulgin, V.I. (M.V. Lomonosov Moscow State Univ. (USSR)); Diaz, C. (Cuba National Center of Scientific Research, Havana (Cuba)); Kharitonov, Yu.Ya.; Cherkasova, O.G. (I.M. Sechenov First Moscow Medical Inst. (USSR))

    1991-11-01

    Moessbauer spectroscopy methods are discussed when applied to test the properties of magnetic suppositories used in medicine. The experiments were carried out on magnetic rectal suppositories containing paramadine and fine-dispersed ferrite powder (BaO.nFe[sub 2]O[sub 3]) as a magnetic filler. According to the data on the value of effective magnetic field on [sup 57]Fe nuclei in ferrite magnetic sublattices, the stoichiometric n-number equals approximately 5.5; this value corresponds to the composition range of optimal magnetic properties. (orig.).

  18. Initial position estimation method for permanent magnet synchronous motor based on improved pulse voltage injection

    DEFF Research Database (Denmark)

    Wang, Z.; Lu, K.; Ye, Y.

    2011-01-01

    According to saliency of permanent magnet synchronous motor (PMSM), the information of rotor position is implied in performance of stator inductances due to the magnetic saturation effect. Researches focused on the initial rotor position estimation of PMSM by injecting modulated pulse voltage...... vectors. The relationship between the inductance variations and voltage vector positions was studied. The inductance variation effect on estimation accuracy was studied as well. An improved five-pulses injection method was proposed, to improve the estimation accuracy by choosing optimaized voltage vectors...

  19. First results of transcritical magnetized collisionless shock studies on MSX

    Science.gov (United States)

    Weber, T. E.; Smith, R. J.; Hutchinson, T. M.; Taylor, S. F.; Hsu, S. C.

    2014-10-01

    Magnetized collisionless shocks exhibit transitional length and time scales much shorter than can be created through collisional processes. They are common throughout the cosmos, but have historically proven difficult to create in the laboratory. The Magnetized Shock Experiment (MSX) at LANL produces super-Alfvénic shocks through the acceleration and subsequent stagnation of Field Reversed Configuration (FRC) plasmoids against a strong magnetic mirror and flux-conserving vacuum boundary. Plasma flows have been produced with sonic and Alfvén Mach numbers up to ~10 over a wide range of plasma beta with embedded perpendicular, oblique, and parallel magnetic field. Macroscopic ion skin-depth and long ion-gyroperiod enable diagnostic access to relevant shock physics using common methods. Variable plasmoid velocity, density, temperature, and magnetic field provide access to a wide range of shock conditions, and a campaign to study the physics of transcritical and supercritical shocks within the FRC plasmoid is currently underway. An overview of the experimental design, diagnostics suite, physics objectives, and recent results will be presented. Supported by DOE Office of Fusion Energy Sciences under DOE Contract DE-AC52-06NA25369.

  20. Modeling of Self-Excited Isolated Permanent Magnet Induction Generator Using Iterative Numerical Method

    Directory of Open Access Journals (Sweden)

    Mohamed Mostafa R.

    2016-01-01

    Full Text Available Self-Excited Permanent Magnet Induction Generator (PMIG is commonly used in wind energy generation systems. The difficulty of Self-Excited Permanent Magnet Induction Generator (SEPMIG modeling is the circuit parameters of the generator vary at each load conditions due to the a change in the frequency and stator voltage. The paper introduces a new modeling for SEPMIG using Gauss-sidle relaxation method. The SEPMIG characteristics using the proposed method are studied at different load conditions according to the wind speed variation, load impedance changes and different shunted capacitor values. The system modeling is investigated due to the magnetizing current variation, the efficiency variation, the power variation and power factor variation. The proposed modeling system satisfies high degree of simplicity and accuracy.

  1. A new method of assembling large magnetic blocks from permanent NdFeB magnets

    Czech Academy of Sciences Publication Activity Database

    Žežulka, Václav; Straka, Pavel

    2007-01-01

    Roč. 4, č. 3 (2007), 75-83 ISSN 1214-9705 Institutional research plan: CEZ:AV0Z30460519 Keywords : magnet assembly * magnet ic circuits * magnet ic separation Subject RIV: BM - Solid Matter Physics ; Magnet ism www.irsm.cas.cz

  2. Positive muon studies of magnetic materials

    International Nuclear Information System (INIS)

    Patterson, B.D.

    1975-01-01

    Polarized positive muons (μ + ) are stopped in magnetic materials, and the μ + precession is observed via the muons's asymmetric decay to a positron. The precession frequency is a measure of the local magnetic field at the μ + . Relaxation of the μ + spin is caused by spatially or time-varying local fields. The local field at a stopped μ + in ferromagnetic nickel is measured. From this measurement, the hyperfine field seen by an interstitial μ + due to its contact interaction with polarized screening electrons is inferred to be -0.66kG. A discussion of this value in terms of a simple model for the screening configuration is presented. Critical spin fluctuations in Ni at temperatures just above the Curie point rapidly relax the μ + spin. The temperature and external magnetic field dependence of the relaxation rate is determined experimentally. A theory for the relaxation rate is presented which demonstrates the importance of the hyperfine and dipolar interactions of the μ + with its Ni host. Preliminary results on μ + studies in ferromagnetic iron and cobalt are also discussed. (U.S.)

  3. Method and means for detecting magnetic deposits in tubular plant

    Energy Technology Data Exchange (ETDEWEB)

    Lord, W

    1981-03-04

    Deposits of magnetite on tubes in a heat exchanger, e.g., a steam generator, are detected by measuring the magnetic reluctance within the tubes. A probe for measuring the reluctance includes a permanent magnet (or a magnetic core and an excitation coil wound on the core) and a magnetic flux detector such as a Hall generator mounted for example on one of the non-magnetic rings. Changes in flux density as the probe is pushed through the tubes are detected by the Hall generator, thus indicating the presence of magnetite deposits. The probe includes a non-magnetic tube for pushing it through the heat exchanger tubes.

  4. Thick film magnetic nanoparticulate composites and method of manufacture thereof

    Science.gov (United States)

    Ma, Xinqing (Inventor); Zhang, Yide (Inventor); Ge, Shihui (Inventor); Zhang, Zongtao (Inventor); Yan, Dajing (Inventor); Xiao, Danny T. (Inventor)

    2009-01-01

    Thick film magnetic/insulating nanocomposite materials, with significantly reduced core loss, and their manufacture are described. The insulator coated magnetic nanocomposite comprises one or more magnetic components, and an insulating component. The magnetic component comprises nanometer scale particles (about 1 to about 100 nanometers) coated by a thin-layered insulating phase. While the intergrain interaction between the immediate neighboring magnetic nanoparticles separated by the insulating phase provides the desired soft magnetic properties, the insulating material provides high resistivity, which reduces eddy current loss.

  5. Non-regularized inversion method from light scattering applied to ferrofluid magnetization curves for magnetic size distribution analysis

    International Nuclear Information System (INIS)

    Rijssel, Jos van; Kuipers, Bonny W.M.; Erné, Ben H.

    2014-01-01

    A numerical inversion method known from the analysis of light scattering by colloidal dispersions is now applied to magnetization curves of ferrofluids. The distribution of magnetic particle sizes or dipole moments is determined without assuming that the distribution is unimodal or of a particular shape. The inversion method enforces positive number densities via a non-negative least squares procedure. It is tested successfully on experimental and simulated data for ferrofluid samples with known multimodal size distributions. The created computer program MINORIM is made available on the web. - Highlights: • A method from light scattering is applied to analyze ferrofluid magnetization curves. • A magnetic size distribution is obtained without prior assumption of its shape. • The method is tested successfully on ferrofluids with a known size distribution. • The practical limits of the method are explored with simulated data including noise. • This method is implemented in the program MINORIM, freely available online

  6. Determination of magnetic characteristics of nanoparticles by low-temperature calorimetry methods

    Energy Technology Data Exchange (ETDEWEB)

    Ugulava, A.; Toklikishvili, Z. [Department of Physics, I.Javakhishvili Tbilisi State University,I.Chavchavadze av. 3, 0179 Tbilisi, Georgia (United States); Chkhaidze, S., E-mail: simon.chkhaidze@tsu.ge [Department of Physics, I.Javakhishvili Tbilisi State University,I.Chavchavadze av. 3, 0179 Tbilisi, Georgia (United States); Kekutia, Sh. [V. Chavchanidze Institute of Cybernetics, at the Technical State University, S. Euli str. 5, 0186 Tbilisi, Georgia (United States)

    2017-05-15

    At low temperatures, the heat capacity of a superparamagnetic “ideal gas” determined by magnetic degrees of freedom can greatly exceed the lattice heat capacity. It is shown that in the presence of an external magnetic field, the temperature dependence of the magnetic part of the heat capacity has two maxima. The relations between the temperature at which these maxima are achieved, the magnetic moment of the nanoparticles and the magnetic anisotropy constant have been obtained. Measuring the heat capacity maxima temperatures by low-temperature calorimetry methods and using the obtained relations, we can obtain the numerical values both of the magnetic moment of nanoparticles and the magnetic anisotropy constants.

  7. Modeling the field of a coil using the magnetic charge method

    NARCIS (Netherlands)

    van Casteren, D.T.E.H.; Paulides, J.J.H.; Lomonova, E.A.

    2017-01-01

    In the last decades the magnetic charge method has proven to be an excellent tool to analyze and design permanent magnet based systems. Recent research has shown that inclusion of the relative permeability of magnetic materials is also possible using the extended charge method. Contrary to popular

  8. In situ baking method for degassing of a kicker magnet in accelerator beam line

    International Nuclear Information System (INIS)

    Kamiya, Junichiro; Ogiwara, Norio; Yanagibashi, Toru; Kinsho, Michikazu; Yasuda, Yuichi

    2016-01-01

    In this study, the authors propose a new in situ degassing method by which only kicker magnets in the accelerator beam line are baked out without raising the temperature of the vacuum chamber to prevent unwanted thermal expansion of the chamber. By simply installing the heater and thermal radiation shield plates between the kicker magnet and the chamber wall, most of the heat flux from the heater directs toward the kicker magnet. The result of the verification test showed that each part of the kicker magnet was heated to above the target temperature with a small rise in the vacuum chamber temperature. A graphite heater was selected in this application to bake-out the kicker magnet in the beam line to ensure reliability and easy maintainability of the heater. The vacuum characteristics of graphite were suitable for heater operation in the beam line. A preliminary heat-up test conducted in the accelerator beam line also showed that each part of the kicker magnet was successfully heated and that thermal expansion of the chamber was negligibly small

  9. In situ baking method for degassing of a kicker magnet in accelerator beam line

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Junichiro, E-mail: kamiya.junichiro@jaea.go.jp; Ogiwara, Norio; Yanagibashi, Toru; Kinsho, Michikazu [Japan Atomic Energy Agency, J-PARC Center, Ooaza Shirakata 2-4, Tokai, Naka, Ibaraki 319-1195 (Japan); Yasuda, Yuichi [SAKAGUCHI E.H VOC CORP., Sakura Dai-san Kogyodanchi 1-8-6, Osaku, Sakura, Chiba 285-0802 (Japan)

    2016-03-15

    In this study, the authors propose a new in situ degassing method by which only kicker magnets in the accelerator beam line are baked out without raising the temperature of the vacuum chamber to prevent unwanted thermal expansion of the chamber. By simply installing the heater and thermal radiation shield plates between the kicker magnet and the chamber wall, most of the heat flux from the heater directs toward the kicker magnet. The result of the verification test showed that each part of the kicker magnet was heated to above the target temperature with a small rise in the vacuum chamber temperature. A graphite heater was selected in this application to bake-out the kicker magnet in the beam line to ensure reliability and easy maintainability of the heater. The vacuum characteristics of graphite were suitable for heater operation in the beam line. A preliminary heat-up test conducted in the accelerator beam line also showed that each part of the kicker magnet was successfully heated and that thermal expansion of the chamber was negligibly small.

  10. Accurate Calculation of Magnetic Fields in the End Regions of Superconducting Accelerator Magnets using the BEM-FEM Coupling Method

    CERN Document Server

    Kurz, S

    1999-01-01

    In this paper a new technique for the accurate calculation of magnetic fields in the end regions of superconducting accelerator magnets is presented. This method couples Boundary Elements (BEM) which discretize the surface of the iron yoke and Finite Elements (FEM) for the modelling of the nonlinear interior of the yoke. The BEM-FEM method is therefore specially suited for the calculation of 3-dimensional effects in the magnets, as the coils and the air regions do not have to be represented in the finite-element mesh and discretization errors only influence the calculation of the magnetization (reduced field) of the yoke. The method has been recently implemented into the CERN-ROXIE program package for the design and optimization of the LHC magnets. The field shape and multipole errors in the two-in-one LHC dipoles with its coil ends sticking out of the common iron yoke is presented.

  11. Electrodeless plasma acceleration system using rotating magnetic field method

    Directory of Open Access Journals (Sweden)

    T. Furukawa

    2017-11-01

    Full Text Available We have proposed Rotating Magnetic Field (RMF acceleration method as one of electrodeless plasma accelerations. In our experimental scheme, plasma generated by an rf (radio frequency antenna, is accelerated by RMF antennas, which consist of two-pair, opposed, facing coils, and these antennas are outside of a discharge tube. Therefore, there is no wear of electrodes, degrading the propulsion performance. Here, we will introduce our RMF acceleration system developed, including the experimental device, e.g., external antennas, a tapered quartz tube, a vacuum chamber, external magnets, and a pumping system. In addition, we can change RMF operation parameters (RMF applied current IRMF and RMF current phase difference ϕ, focusing on RMF current frequency fRMF by adjusting matching conditions of RMF, and investigate the dependencies on plasma parameters (electron density ne and ion velocity vi; e.g., higher increases of ne and vi (∼360 % and 55 %, respectively than previous experimental results were obtained by decreasing fRMF from 5 MHz to 0.7 MHz, whose RMF penetration condition was better according to Milroy’s expression. Moreover, time-varying component of RMF has been measured directly to survey the penetration condition experimentally.

  12. Applications of neutron scattering to the study of magnetic materials

    International Nuclear Information System (INIS)

    Koehler, W.C.

    1976-01-01

    The types of interactions that neutrons undergo with condensed matter are reviewed and those properties of neutrons that make them an ideal probe for the study of magnetism on a microscopic scale are discussed. Following a very brief survey of experimental methods, a few illustrative examples of specific investigations are described in sufficient detail to illustrate the power of the techniques. Views as to the future directions that may be taken by neutron scattering are presented

  13. Effect of a uniform magnetic field on dielectric two-phase bubbly flows using the level set method

    International Nuclear Information System (INIS)

    Ansari, M.R.; Hadidi, A.; Nimvari, M.E.

    2012-01-01

    In this study, the behavior of a single bubble in a dielectric viscous fluid under a uniform magnetic field has been simulated numerically using the Level Set method in two-phase bubbly flow. The two-phase bubbly flow was considered to be laminar and homogeneous. Deformation of the bubble was considered to be due to buoyancy and magnetic forces induced from the external applied magnetic field. A computer code was developed to solve the problem using the flow field, the interface of two phases, and the magnetic field. The Finite Volume method was applied using the SIMPLE algorithm to discretize the governing equations. Using this algorithm enables us to calculate the pressure parameter, which has been eliminated by previous researchers because of the complexity of the two-phase flow. The finite difference method was used to solve the magnetic field equation. The results outlined in the present study agree well with the existing experimental data and numerical results. These results show that the magnetic field affects and controls the shape, size, velocity, and location of the bubble. - Highlights: ►A bubble behavior was simulated numerically. ► A single bubble behavior was considered in a dielectric viscous fluid. ► A uniform magnetic field is used to study a bubble behavior. ► Deformation of the bubble was considered using the Level Set method. ► The magnetic field affects the shape, size, velocity, and location of the bubble.

  14. Method for the determination of Clebsch-Gordan coefficients of finite magnetic groups

    NARCIS (Netherlands)

    van den Broek, P.M.; Horowitz, L.P.; Ne'eman, Y.

    1980-01-01

    A recent method for the determination of Clebsch-Gordan coefficients of finite magnetic groups is generalised to magnetic groups. Discussion is restricted to unitary-anti-unitary representations of type I.

  15. Composite Materials with Magnetically Aligned Carbon Nanoparticles and Methods of Preparation

    Science.gov (United States)

    Hong, Haiping (Inventor); Peterson, G.P. (Bud) (Inventor); Salem, David R. (Inventor)

    2018-01-01

    The present invention relates to magnetically aligned carbon nanoparticle composites and methods of preparing the same. The composites comprise carbon nanoparticles, host material, magnetically sensitive nanoparticles and surfactant. The composites may have enhanced mechanical, thermal, and/or electrical properties.

  16. The Analysis of Quadrupole Magnetic Focusing Effect by Finite Element Method

    International Nuclear Information System (INIS)

    Utaja

    2003-01-01

    Quadrupole magnets will introduce focusing effect to a beam of the charge particle passing parallel to the magnet faces. The focusing effect is need to control the particle beam, so that it is in accordance with necessity requirement stated. This paper describes the analysis of focusing effect on the quadrupole magnetic by the finite element method. The finite element method in this paper is used for solve the potential distribution of magnetic field. If the potential magnetic field distribution in every node have known, a charge particle trajectory can be traced. This charge particle trajectory will secure the focusing effect of the quadrupole magnets. (author)

  17. Magnetic properties and phase transformations of iron sulfides synthesized under the hydrothermal method

    Science.gov (United States)

    Li, S. H.; Chen, Y. H.

    2016-12-01

    The iron sulfide nano-minerals possess advantages of high abundance, low cost, and low toxicity. These advantages make them be competitive in the magnetic, electronic, and photoelectric applications. Mackinawite can be used in soil or water remediations. Greigite is very important for paleomagnetic and geochemical environment studies and the anode materials for lithium ion batteries. Besides, greigite is also utilized for hyperthermia and biomedicine. Pyrrhotite can be applied as geothermometry. Due to the above-mentioned reasons, iron sulfide minerals have specific significances and they must be further investigated, like their phase transformations, magnetic properties, and etc. In this study, the iron sulfide minerals were synthesized by using a hydrothermal method. The ex-situ and in-situ X-ray diffraction (XRD) was used to examine the crystal structure and phase transformation of iron sulfide minerals. The Transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID) were carried out to investigate their morphology and magnetic properties, respectively. The results suggested that the phase transformation sequence was followed the order: mackinawite → greigite → (smythite) → pyrrhotite. Two pure mineral phases of greigite and pyrrhotite were obtained under the hydrothermal conditions. The morphology of the pure greigite is granular aggregates with a particle size of approximately 30 nm and pyrrhotite presented a hexagonal sheet stacking with a particle size of thousands nanometers. The greigite had a ferri-magnetic behavior and pyrrhotite was weak ferro-magnetic. Both of them had a pseudo-single magnetic domain (PSD) based on the Day's plot from SQUID data. The complete phase-transformation pathways and high magnetization of iron sulfide minerals are observed in this study and these kind of iron sulfide minerals are worthy to further study.

  18. Study of the performance of Micromegas detectors in magnetic field

    Science.gov (United States)

    Dimitrios, Sampsonidis

    2018-02-01

    Resistive Micromegas (MICRO MEsh GAseous Structure) detectors have been chosen by the ATLAS collaboration at LHC for the high luminosity upgrade, due to their capability to maintain full efficiency and high spatial resolution at high occupancy, for tracking muons in the forward region of the detector. The Inner Muon Station, in the high-rapidity region, the so called New Small Wheel (NSW), will be composed of micromegas detectors that will have to maintain good performance in the presence of magnetic field of up to about 0.3 T. The response of micromegas detectors is affected by the magnetic field, where the deflection of the drift electrons is described by the Lorentz angle, resulting in a bias in the reconstructed track position. Several test-beam campaigns have been performed to test the behaviour of small size resistive micromegas prototypes (10×10 cm2) in magnetic fields up to 1 T, using high momentum muon and hadron beams at CERN. These studies are performed in order to validate the capability of the chambers to provide unbiased tracks in the NSW conditions. Measurements of the Lorentz angle and drift velocity as a function of the magnetic field are presented and both are compared to expectations based on Garfield-Magboltz simulations. Several methods to correct the position bias are applied, based on the chamber configuration or on the knowledge of the local value of the magnetic field. The results of these studies are presented together with an overall discussion of the Micromegas tracking capability in magnetic field.

  19. Study of the performance of Micromegas detectors in magnetic field

    Directory of Open Access Journals (Sweden)

    Dimitrios Sampsonidis

    2018-01-01

    Full Text Available Resistive Micromegas (MICRO MEsh GAseous Structure detectors have been chosen by the ATLAS collaboration at LHC for the high luminosity upgrade, due to their capability to maintain full efficiency and high spatial resolution at high occupancy, for tracking muons in the forward region of the detector. The Inner Muon Station, in the high-rapidity region, the so called New Small Wheel (NSW, will be composed of micromegas detectors that will have to maintain good performance in the presence of magnetic field of up to about 0.3 T. The response of micromegas detectors is affected by the magnetic field, where the deflection of the drift electrons is described by the Lorentz angle, resulting in a bias in the reconstructed track position. Several test-beam campaigns have been performed to test the behaviour of small size resistive micromegas prototypes (10×10 cm2 in magnetic fields up to 1 T, using high momentum muon and hadron beams at CERN. These studies are performed in order to validate the capability of the chambers to provide unbiased tracks in the NSW conditions. Measurements of the Lorentz angle and drift velocity as a function of the magnetic field are presented and both are compared to expectations based on Garfield-Magboltz simulations. Several methods to correct the position bias are applied, based on the chamber configuration or on the knowledge of the local value of the magnetic field. The results of these studies are presented together with an overall discussion of the Micromegas tracking capability in magnetic field.

  20. RHQT Nb3Al 15-Tesla magnet design study

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, R.; Ambrosio, G.; Barzi, E.; Kashikin, V.; Kikuchi, A.; Novitski, I.; Takeuchi, T.; Wake, M.; Zlobin, A.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba

    2005-09-01

    Feasibility study of 15-Tesla dipole magnets wound with a new copper stabilized RHQT Nb{sub 3}Al Rutherford cable is presented. A new practical long copper stabilized RHQT Nb{sub 3}Al strand is presented, which is being developed and manufactured at the National Institute of Material Science (NIMS) in Japan. It has achieved a non-copper J{sub c} of 1000A/mm{sup 2} at 15 Tesla at 4.2K, with a copper over non-copper ratio of 1.04, and a filament size less than 50 microns. For this design study a short Rutherford cable with 28 Nb{sub 3}Al strands of 1 mm diameter will be fabricated late this year. The cosine theta magnet cross section is designed using ROXIE, and the stress and strain in the coil is estimated and studied with the characteristics of the Nb{sub 3}Al strand. The advantages and disadvantages of the Nb{sub 3}Al cable are compared with the prevailing Nb{sub 3}Sn cable from the point of view of stress-strain, J{sub c}, and possible degradation of stabilizer due to cabling. The Nb{sub 3}Al coil of the magnet, which will be made by wind and react method, has to be heat treated at 800 degree C for 10 hours. As preparation for the 15 Tesla magnet, a series of tests on strand and Rutherford cables are considered.

  1. Flake graphite cast iron investigated by a magnetic method

    Czech Academy of Sciences Publication Activity Database

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

    2014-01-01

    Roč. 50, č. 4 (2014), s. 6200404 ISSN 0018-9464 Institutional support: RVO:68378271 Keywords : cast iron * magnetic adaptive testing (MAT) * magnetic nondestructive evaluation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.386, year: 2014

  2. Magnetic separator having a multilayer matrix, method and apparatus

    Science.gov (United States)

    Kelland, David R.

    1980-01-01

    A magnetic separator having multiple staggered layers of porous magnetic material positioned to intercept a fluid stream carrying magnetic particles and so placed that a bypass of each layer is effected as the pores of the layer become filled with material extracted from the fluid stream.

  3. Method for introducing bias magnetization in ungaped cores

    DEFF Research Database (Denmark)

    Aguilar, Andres Revilla; Munk-Nielsen, Stig

    2014-01-01

    The use of permanent magnets for bias magnetization is a known technique to increase the energy storage capability in DC inductors, resulting in a size reduction or increased current rating. This paper presents a brief introduction on the different permanent magnet inductor’s configurations found...

  4. Light-free magnetic resonance force microscopy for studies of electron spin polarized systems

    International Nuclear Information System (INIS)

    Pelekhov, Denis V.; Selcu, Camelia; Banerjee, Palash; Chung Fong, Kin; Chris Hammel, P.; Bhaskaran, Harish; Schwab, Keith

    2005-01-01

    Magnetic resonance force microscopy is a scanned probe technique capable of three-dimensional magnetic resonance imaging. Its excellent sensitivity opens the possibility for magnetic resonance studies of spin accumulation resulting from the injection of spin polarized currents into a para-magnetic collector. The method is based on mechanical detection of magnetic resonance which requires low noise detection of cantilever displacement; so far, this has been accomplished using optical interferometry. This is undesirable for experiments on doped silicon, where the presence of light is known to enhance spin relaxation rates. We report a non-optical displacement detection scheme based on sensitive microwave capacitive readout

  5. Layered magnets: polarized neutron reflection studies

    Energy Technology Data Exchange (ETDEWEB)

    Zabel, H; Schreyer, A [Ruhr-Univ. Bochum, Lehrstuhl fuer Experimentalphysik/Festkoerperphysik, Bochum (Germany)

    1996-11-01

    Neutron reflectivity measurements from extended surfaces, thin films and superlattices provide information on the chemical profile parallel to the film normal, including film thicknesses, average composition and interfacial roughness parameters. Reflectivity measurements with polarized neutrons are particularly powerful for analyzing the magnetic density profiles in thin films and superlattices in addition to chemical profiles. The basic theory of polarized neutron reflectivity is provided, followed by some examples and more recent applications concerning polarized neutron reflectivity studies from exchange coupled Fe/Cr superlattices. (author) 5 figs., 13 refs.

  6. Methods and apparatuses for low-noise magnetic sensors

    KAUST Repository

    Kosel, Jü rgen; Sun, Jian

    2015-01-01

    Magnetic sensors are disclosed, as well as methods for fabricating and using the same. In some embodiments, an EMR effect sensor includes a semiconductor layer. In some embodiments, the EMR effect sensor may include a conductive layer substantially coupled to the semiconductor layer. In some embodiments, the EMR effect sensor may include a first voltage lead coupled to the semiconductor layer. In some embodiments, the first voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. In some embodiments, the EMR effect sensor may include a second voltage lead coupled to the conductive layer. In some embodiments, the second voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. Embodiments of a Hall effect sensor having the same or similar structure are also disclosed.

  7. Deenergizing method of superconducting magnets for Maglev in an emergency

    Energy Technology Data Exchange (ETDEWEB)

    Kishikawa, Akihiko [Railway Technical Research Inst., Tokyo (Japan); Nemoto, Kaoru [Railway Technical Research Inst., Tokyo (Japan)

    1996-12-31

    The running stability of the superconducting magnets (SCMs) mounted on the JR Maglev vehicle has been confirmed through many researches and actual running tests. So we could confirm that the high performance of our SCMs during the last few years, but we must bear in mind that the SCM which consists of the superconducting wire has the possibility of changing into normal resistive state from superconducting state. If one of the pair SCMs normalizes, a huge lateral force on one side of a bogie will occur suddenly and push the vehicle toward the sidewall of the guideway. This paper describes the method that reduces this huge force acting on one side of a bogie in an SCM accident. (orig.)

  8. Methods and apparatuses for low-noise magnetic sensors

    KAUST Repository

    Kosel, Jurgen

    2015-10-20

    Magnetic sensors are disclosed, as well as methods for fabricating and using the same. In some embodiments, an EMR effect sensor includes a semiconductor layer. In some embodiments, the EMR effect sensor may include a conductive layer substantially coupled to the semiconductor layer. In some embodiments, the EMR effect sensor may include a first voltage lead coupled to the semiconductor layer. In some embodiments, the first voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. In some embodiments, the EMR effect sensor may include a second voltage lead coupled to the conductive layer. In some embodiments, the second voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. Embodiments of a Hall effect sensor having the same or similar structure are also disclosed.

  9. An Improved Method for Magnetic Nanocarrier Drug Delivery across the Cell Membrane

    Directory of Open Access Journals (Sweden)

    Behzad Mehrafrooz

    2018-01-01

    Full Text Available One of the crucial issues in the pharmacological field is developing new drug delivery systems. The main concern is to develop new methods for improving the drug delivery efficiencies such as low disruptions, precise control of the target of delivery and drug sustainability. Nowadays, there are many various methods for drug delivery systems. Carbon-based nanocarriers are a new efficient tool for translocating drug into the defined area or cells inside the body. These nanocarriers can be functionalized with proteins, peptides and used to transport their freight to cells or defined areas. Since functionalized carbon-based nanocarriers show low toxicity and high biocompatibility, they are used in many nanobiotechnology fields. In this study, different shapes of nanocarrier are investigated, and the suitable magnetic field, which is applied using MRI for the delivery of the nanocarrier, is proposed. In this research, based on the force required to cross the membrane and MD simulations, the optimal magnetic field profile is designed. This optimal magnetic force field is derived from the mathematical model of the system and magnetic particle dynamics inside the nanocarrier. The results of this paper illustrate the effects of the nanocarrier’s shapes on the percentage of success in crossing the membrane and the optimal required magnetic field.

  10. Magnetic signature of overbank sediment in industry impacted floodplains identified by data mining methods

    Science.gov (United States)

    Chudaničová, Monika; Hutchinson, Simon M.

    2016-11-01

    Our study attempts to identify a characteristic magnetic signature of overbank sediments exhibiting anthropogenically induced magnetic enhancement and thereby to distinguish them from unenhanced sediments with weak magnetic background values, using a novel approach based on data mining methods, thus providing a mean of rapid pollution determination. Data were obtained from 539 bulk samples from vertical profiles through overbank sediment, collected on seven rivers in the eastern Czech Republic and three rivers in northwest England. k-Means clustering and hierarchical clustering methods, paired group (UPGMA) and Ward's method, were used to divide the samples to natural groups according to their attributes. Interparametric ratios: SIRM/χ; SIRM/ARM; and S-0.1T were chosen as attributes for analyses making the resultant model more widely applicable as magnetic concentration values can differ by two orders. Division into three clusters appeared to be optimal and corresponded to inherent clusters in the data scatter. Clustering managed to separate samples with relatively weak anthropogenically induced enhancement, relatively strong anthropogenically induced enhancement and samples lacking enhancement. To describe the clusters explicitly and thus obtain a discrete magnetic signature, classification rules (JRip method) and decision trees (J4.8 and Simple Cart methods) were used. Samples lacking anthropogenic enhancement typically exhibited an S-0.1T 0.5. Samples with relatively stronger anthropogenic enhancement were unequivocally distinguished from the samples with weaker enhancement by an SIRM/ARM > c. 150. Samples with SIRM/ARM in a range c. 126-150 were classified as relatively strongly enhanced when their SIRM/χ > 18 000 A m-1 and relatively less enhanced when their SIRM/χ 6 per cent from anthropogenically enhanced clusters as samples with natural magnetic enhancement. The characteristics of the clusters resulted mainly from the relationship between SIRM/ARM and

  11. Development of technology for the in-service inspection of reactor pressure vessel metal condition using a magnetic method

    International Nuclear Information System (INIS)

    Bakirov, M. B.; Zabruskov, N.Y; Massoud, J.P.

    2002-01-01

    The opportunity to perform the inspection of condition of base metal and metal of welded joints of cladded vessels of PWR by non destructive methods is shown. The technique for on-site specimen-free testing is offered on the basis of sharing a kinetic hardness method and magnetic method. The results of studies of magnetic and mechanical properties of vessel steels in various condition after irradiation and thermal processing are submitted. It is shown, that the magnetic properties (first of all coercive force) are sensitive to change of structure of a material. (authors)

  12. Response of Gravity, Magnetic, and Geoelectrical Resistivity Methods on Ngeni Southern Blitar Mineralization Zone

    Science.gov (United States)

    Sunaryo

    2018-03-01

    The research with entitle response of gravity, magnetic, and geoelectrical resistivity methods on Ngeni Southern Blitar mineralization zone has been done. This study aims to find the response of several geophysical methods of gravity, magnetic, and geoelectrical resistivity in an integrated manner. Gravity data acquisition was acquired 224 data which covers the whole region of Blitar district by using Gravity Meter La Coste & Romberg Model “G”, and magnetic data acquisition were acquired 195 data which covers the southern Blitar district only by using Proton Precession Magnetometer G-856. Meanwhile geoelectrical resistivity data only done in Ngeni village which is the location of phyropilite mining with the composition content of Fe, Si, Ca, S, Cu, and Mn by using ABEM Terrameter SAS 300C. Gravity data processing was performed to obtain the Bouguer anomaly value, which included unit conversion, tidal correction, drift correction, correction of tie point, base station correction, free air correction, and Bouguer correction. Magnetic data processing has been done by some corrections i.e daily, drift, and IGRF(International Geomagnetic Refference Field) to obtain the total magnetic anomaly. From gravity data processing has been obtained the simple Bouguer anomaly value in range from -10mGal until 115mGal. From this data processing has been obtained the total magnetic anomaly value in range from -650nT until 800nT. Meanwhile from geoelectrical resistivity 3.03Ωm until 11249.91 Ωm. There is a correlation between gravity anomaly, magnetic anomaly, and geoelectrical resistivity anomaly that are associated with deep anomaly, middle anomaly, and shallow anomaly.

  13. Distribution functions of magnetic nanoparticles determined by a numerical inversion method

    International Nuclear Information System (INIS)

    Bender, P; Balceris, C; Ludwig, F; Posth, O; Bogart, L K; Szczerba, W; Castro, A; Nilsson, L; Costo, R; Gavilán, H; González-Alonso, D; Pedro, I de; Barquín, L Fernández; Johansson, C

    2017-01-01

    In the present study, we applied a regularized inversion method to extract the particle size, magnetic moment and relaxation-time distribution of magnetic nanoparticles from small-angle x-ray scattering (SAXS), DC magnetization (DCM) and AC susceptibility (ACS) measurements. For the measurements the particles were colloidally dispersed in water. At first approximation the particles could be assumed to be spherically shaped and homogeneously magnetized single-domain particles. As model functions for the inversion, we used the particle form factor of a sphere (SAXS), the Langevin function (DCM) and the Debye model (ACS). The extracted distributions exhibited features/peaks that could be distinctly attributed to the individually dispersed and non-interacting nanoparticles. Further analysis of these peaks enabled, in combination with a prior characterization of the particle ensemble by electron microscopy and dynamic light scattering, a detailed structural and magnetic characterization of the particles. Additionally, all three extracted distributions featured peaks, which indicated deviations of the scattering (SAXS), magnetization (DCM) or relaxation (ACS) behavior from the one expected for individually dispersed, homogeneously magnetized nanoparticles. These deviations could be mainly attributed to partial agglomeration (SAXS, DCM, ACS), uncorrelated surface spins (DCM) and/or intra-well relaxation processes (ACS). The main advantage of the numerical inversion method is that no ad hoc assumptions regarding the line shape of the extracted distribution functions are required, which enabled the detection of these contributions. We highlighted this by comparing the results with the results obtained by standard model fits, where the functional form of the distributions was a priori assumed to be log-normal shaped. (paper)

  14. Prospecting for the ferromagnetic mineral accumulations using the magnetic method at the Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    Rabeh, Taha

    2009-01-01

    In this study we delineate the subsurface structures within an area of about 145 000 km 2 in the Central Eastern Desert of Egypt (CED), using magnetic methods. The main goal is to establish the tectonic framework of the study area and to understand the role of tectonics in the mineralization process. Aeromagnetic data covering the study area were used, and also detailed land magnetic surveys were carried out along profiles. More than 300 rock samples were collected for laboratory measurements of magnetic susceptibility. The data set was processed using a series of techniques, namely trend analysis, 3D Euler deconvolution, Werner deconvolution and 2.5 direct modelling. Results indicate that the most predominant tectonic trends are E–W, N15°–25°W and N45°W. The depth to the basement estimates range from the surface to 1.8 km. These results agree with the drilled well data. The measured magnetic susceptibility values range between 0.0001 SI and 5 SI. The high susceptibility values strongly suggest that ferromagnetic minerals accompany the mafic metavolcanics along the shear zones at Barramiya, Hafafit, Dawi and Abu Swayel. We show a good correlation between the structures deduced from the magnetic analysis and the known mineral distributions. Most of these ore accumulations are restricted to the major tectonic shear zones with a NW–SE direction. We conclude that mineralization is structurally controlled by faulting, probably as a result of hydrothermal circulation along fault planes

  15. EXPERIMENTAL STUDY OF MAGNETIC FLUID SEAL

    Directory of Open Access Journals (Sweden)

    V. G. Bashtovoi

    2006-01-01

    Full Text Available Dependences of critical pressure drop, being held by magnetic fluid seal, on time in a static state and shaft rotation velocity in dynamics have been experimentally determined. The significant influence of particles’ redistribution in magnetic fluid on static parameters of magnetic fluid seal has been established.

  16. High resolution method for the magnetic axis localization for multipole magnets on the base of the garnet films technology

    International Nuclear Information System (INIS)

    Gertsev, K.F.; Gribkov, V.L.; Liskov, V.A.; Chervonenkis, A.J.

    1992-01-01

    The methods of stretched wires for the localization of the magnetic axis may be inconvenient sometimes in accelerators and colliders of very high energies because of high gradients, large lengths and small apertures. High gradients may deform the wires due to the nonzero magnetic susceptibility and microscopic ferromagnetic particles on their surface. Long wires have large sagittas and small apertures of magnets limit the transversal working domains for the measuring devices. Precision optics magnets possess extreme parameters, in particular, in interaction regions. The magneto-optic (MO) methods of the measurements present some new possibilities for the solution of the above problems. The use of MO films for magnetic field visualization and mapping was proposed and shown that on the basis of Bi-substituted iron garnet films and MO Faraday effect it's possible to obtain the quantitative vector maps of complicated magnetic field structure. Later this was described on a large scale. This method was discussed in terms of its applicability to the magnetic axis localization in quadrupoles of accelerators. In our opinion, the films technology has great advantages as compared with the colloidal solution. In this paper the principles and variants of the films method are presented and further development of the method under discussion is described

  17. Magnetic study of iron-containing carbon nanotubes: Feasibility for magnetic hyperthermia

    Energy Technology Data Exchange (ETDEWEB)

    Krupskaya, Y. [Leibniz-Institute for Solid State and Materials Research IFW Dresden, 01171 Dresden (Germany)], E-mail: y.krupskaya@ifw-dresden.de; Mahn, C.; Parameswaran, A. [Leibniz-Institute for Solid State and Materials Research IFW Dresden, 01171 Dresden (Germany); Taylor, A.; Kraemer, K. [Department of Urology, Dresden University of Technology, 01307 Dresden (Germany); Hampel, S.; Leonhardt, A.; Ritschel, M.; Buechner, B.; Klingeler, R. [Leibniz-Institute for Solid State and Materials Research IFW Dresden, 01171 Dresden (Germany)

    2009-12-15

    We present a detailed magnetic study of iron containing carbon nanotubes (Fe-CNT), which highlights their potential for contactless magnetic heating in hyperthermia cancer treatment. Magnetic field dependent AC inductive heating experiments on Fe-CNT dispersions show a substantial temperature increase of Fe-CNT dispersions in applied AC magnetic fields. DC and AC magnetization studies have been done in order to elucidate the heating mechanism. We observe a different magnetic response of Fe-CNT powder compared to Fe-CNT dispersed in aqueous solution, e.g., ferromagnetic Fe-CNT in powder do not show any hysteresis when being dispersed in liquid. Our data indicate the motion of Fe-CNT in liquid in applied magnetic fields.

  18. 2D-PES/XAS method for atomic-layer-resolved magnetic structure analysis

    International Nuclear Information System (INIS)

    Matsui, F.; Daimon, H.; Matsushita, T.; Guo, F.Z.

    2008-01-01

    Photoelectron and Auger electron angular distributions from a localized core level provide information on atomic configurations. Forward-focusing peaks indicate the directions of atoms surrounding the excited atom. X-ray absorption fine structure and X-ray magnetic circular dichroism measurements by Auger electron yield detection on the other hand are excellent methods for studying of the electronic and magnetic structures of surfaces, adsorbates, and thin films. However, all the information from atoms within the electron mean-free-path region is averaged into the obtained spectra. Here, we introduce a new method of X-ray absorption spectroscopy (XAS) combined with measurements of Auger electron angular distribution using a display-type analyzer. Taking advantage of the forward-focusing peak as an excellent element- and site-selective probe, 2D-XAS enables direct access to the individual electronic and magnetic structures of each atomic layer. This method was applied to studying the electronic and magnetic structures of Ni thin film at atomic level. (author)

  19. Precision of a FDTD method to simulate cold magnetized plasmas

    International Nuclear Information System (INIS)

    Pavlenko, I.V.; Melnyk, D.A.; Prokaieva, A.O.; Girka, I.O.

    2014-01-01

    The finite difference time domain (FDTD) method is applied to describe the propagation of the transverse electromagnetic waves through the magnetized plasmas. The numerical dispersion relation is obtained in a cold plasma approximation. The accuracy of the numerical dispersion is calculated as a function of the frequency of the launched wave and time step of the numerical grid. It is shown that the numerical method does not reproduce the analytical results near the plasma resonances for any chosen value of time step if there is not a dissipation mechanism in the system. It means that FDTD method cannot be applied straightforward to simulate the problems where the plasma resonances play a key role (for example, the mode conversion problems). But the accuracy of the numerical scheme can be improved by introducing some artificial damping of the plasma currents. Although part of the wave power is lost in the system in this case but the numerical scheme describes the wave processes in an agreement with analytical predictions.

  20. μ+-meson method of investigation of monocrystalline samples of ferromagnetic metals magnetized to saturation

    International Nuclear Information System (INIS)

    Gorelkin, V.N.; Miloserdin, V.Yu.; Smilga, V.P.

    1977-01-01

    Analysis and calculation have been performed with respect to local magnetic fields in nickel, cobalt and iron lattices with the use of the Ehwald's method. Based on the calculation results regularities have been established of the behaviour of muons in the given ferromagnetic materials in the absence of muon diffusion. It has been found that the μ + meson method makes it possible to study the position of a hydrogen light isotope (muonium) in the metal crystal lattice, deformation and stressed state of the lattice, to measure the contact and dipole fields. The advantages of the μ + meson method in the study of ferromagnetic properties are shown

  1. An experimental study on magnet for electro-magnetic suspension MagLev vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bong Seop; Chung, Hyun Kap [Korea Institute of Machinery and Metals (Korea, Republic of)

    1995-07-01

    This paper deals with characteristics of magnet that the levitation and guidance forces at static state and we tested and evaluated its. Also we compared to effect of levitation force with material and shape of guide way, focus on evaluation and method of test for the magnet of Urban Transit Maglev vehicle. (author). 3 refs., 9 figs., 2 tabs.

  2. Magnetic skyrmions

    Science.gov (United States)

    2018-06-01

    Welcome to the special issue of Journal of Magnetism and Magnetic Materials on magnetic skyrmions. We are proud to present, with great pleasure, a timely collection of 9 original research articles on the recent hot topic "magnetic skyrmions" which studies the static and dynamic properties of skyrmions and the methods to control them in a variety of ways, including magnetic field, electric current and applied strain.

  3. Design study of the KIRAMS-430 superconducting cyclotron magnet

    International Nuclear Information System (INIS)

    Kim, Hyun Wook; Kang, Joonsun; Hong, Bong Hwan; Jung, In Su

    2016-01-01

    Design study of superconducting cyclotron magnet for the carbon therapy was performed at the Korea Institute of Radiological and Medical Science (KIRAMS). The name of this project is The Korea Heavy Ion Medical Accelerator (KHIMA) project and a fixed frequency cyclotron with four spiral sector magnet was one of the candidate for the accelerator type. Basic parameters of the cyclotron magnet and its characteristics were studied. The isochronous magnetic field which can guide the "1"2C"6"+ ions up to 430 MeV/u was designed and used for the single particle tracking simulation. The isochronous condition of magnetic field was achieved by optimization of sector gap and width along the radius. Operating range of superconducting coil current was calculated and changing of the magnetic field caused by mechanical deformations of yokes was considered. From the result of magnetic field design, structure of the magnet yoke was planned.

  4. Design study of the KIRAMS-430 superconducting cyclotron magnet

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Wook; Kang, Joonsun, E-mail: genuinei@kirams.re.kr; Hong, Bong Hwan; Jung, In Su

    2016-07-01

    Design study of superconducting cyclotron magnet for the carbon therapy was performed at the Korea Institute of Radiological and Medical Science (KIRAMS). The name of this project is The Korea Heavy Ion Medical Accelerator (KHIMA) project and a fixed frequency cyclotron with four spiral sector magnet was one of the candidate for the accelerator type. Basic parameters of the cyclotron magnet and its characteristics were studied. The isochronous magnetic field which can guide the {sup 12}C{sup 6+} ions up to 430 MeV/u was designed and used for the single particle tracking simulation. The isochronous condition of magnetic field was achieved by optimization of sector gap and width along the radius. Operating range of superconducting coil current was calculated and changing of the magnetic field caused by mechanical deformations of yokes was considered. From the result of magnetic field design, structure of the magnet yoke was planned.

  5. Large Coil Program magnetic system design study

    International Nuclear Information System (INIS)

    Moses, S.D.; Johnson, N.E.

    1977-01-01

    The primary objective of the Large Coil Program (LCP) is to demonstrate the reliable operation of large superconducting coils to provide a basis for the design principles, materials, and fabrication techniques proposed for the toroidal magnets for the THE NEXT STEP (TNS) and other future tokamak devices. This paper documents a design study of the Large Coil Test Facility (LCTF) in which the structural response of the Toroidal Field (TF) Coils and the supporting structure was evaluated under simulated reactor conditions. The LCP test facility structural system consists of six TF Coils, twelve coil-to-coil torsional restraining beams (torque rings), a central bucking post with base, and a Pulse Coil system. The NASTRAN Finite Element Structural Analysis computer Code was utilized to determine the distribution of deflections, forces, and stresses for each of the TF Coils, torque rings, and the central bucking post. Eleven load conditions were selected to represent probable test operations. Pulse Coils suspended in the bore of the test coil were energized to simulate the pulsed field environment characteristic of the TNS reactor system. The TORMAC Computer Code was utilized to develop the magnetic forces in the TF Coils for each of the eleven loading conditions examined, with or without the Pulse Coils energized. The TORMAC computer program output forces were used directly as input load conditions for the NASTRAN analyses. Results are presented which demonstrate the reliability of the LCTF under simulated reactor operating conditions

  6. Advanced Magnetic Materials Methods and Numerical Models for Fluidization in Microgravity and Hypogravity

    Science.gov (United States)

    Atwater, James; Wheeler, Richard, Jr.; Akse, James; Jovanovic, Goran; Reed, Brian

    2013-01-01

    To support long-duration manned missions in space such as a permanent lunar base, Mars transit, or Mars Surface Mission, improved methods for the treatment of solid wastes, particularly methods that recover valuable resources, are needed. The ability to operate under microgravity and hypogravity conditions is essential to meet this objective. The utilization of magnetic forces to manipulate granular magnetic media has provided the means to treat solid wastes under variable gravity conditions by filtration using a consolidated magnetic media bed followed by thermal processing of the solid wastes in a fluidized bed reactor. Non-uniform magnetic fields will produce a magnetic field gradient in a bed of magnetically susceptible media toward the distributor plate of a fluidized bed reactor. A correctly oriented magnetic field gradient will generate a downward direct force on magnetic media that can substitute for gravitational force in microgravity, or which may augment low levels of gravity, such as on the Moon or Mars. This approach is termed Gradient Magnetically Assisted Fluidization (G-MAFB), in which the magnitude of the force on the fluidized media depends upon the intensity of the magnetic field (H), the intensity of the field gradient (dH/dz), and the magnetic susceptibility of the media. Fluidized beds based on the G-MAFB process can operate in any gravitational environment by tuning the magnetic field appropriately. Magnetic materials and methods have been developed that enable G-MAFB operation under variable gravity conditions.

  7. Lithium ferrite: The study on magnetic and complex permittivity characteristics

    Directory of Open Access Journals (Sweden)

    Madhavaprasad Dasari

    2017-03-01

    Full Text Available Lithium ferrite (Li0.5Fe2.5O4 powder was prepared by solid state reaction method, which was finally pressed and sintered at 1150 °C. The spinel structure of the lithium ferrite was confirmed by X-ray diffraction and grain size estimation was obtained from scanning electron microscope (SEM. Fourier transform infrared spectroscopy (FTIR confirmed the presence of primary and secondary absorption bands characteristic for spinel structure. The force constants were estimated using absorption bands for the lithium ferrite. Magnetization and dielectric studies were carried out for the sintered sample. Saturation magnetization (Ms of 59.6 emu/g was achieved and variation of magnetization with temperature was used to identify the Curie temperature. The complex permittivity (ε∗ for the lithium ferrite sample was obtained for wide frequency range up to 3 GHz and discussed based on available models. The Curie temperature was estimated around 480 °C and verified from both magnetization versus temperature and dielectric constant versus temperature measurements.

  8. Heating ability and biocompatibility study of silica-coated magnetic ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 38; Issue 6. Heating ability and biocompatibility study of silica-coated magnetic nanoparticles as heating mediators for magnetic hyperthermia and magnetically triggered drug delivery systems. Meysam Soleymani Mohammad Edrissi. Volume 38 Issue 6 October 2015 ...

  9. Magnetic enzyme reactors for isolation and study of heterogeneous glycoproteins

    International Nuclear Information System (INIS)

    Korecka, Lucie; Jezova, Jana; Bilkova, Zuzana; Benes, Milan; Horak, Daniel; Hradcova, Olga; Slovakova, Marcela; Viovy, Jean-Louis

    2005-01-01

    The newly developed magnetic micro- and nanoparticles with defined hydrophobicity and porosity were used for the preparation of magnetic enzyme reactors. Magnetic particles with immobilized proteolytic enzymes trypsin, chymotrypsin and papain and with enzyme neuraminidase were used to study the structure of heterogeneous glycoproteins. Factors such as the type of carrier, immobilization procedure, operational and storage stability, and experimental conditions were optimized

  10. Experimental studies of the magnetized friction force

    International Nuclear Information System (INIS)

    Fedotov, A. V.; Litvinenko, V. N.; Gaalnander, B.; Lofnes, T.; Ziemann, V.; Sidorin, A.; Smirnov, A.

    2006-01-01

    High-energy electron cooling, presently considered as an essential tool for several applications in high-energy and nuclear physics, requires an accurate description of the friction force which ions experience by passing through an electron beam. Present low-energy electron coolers can be used for a detailed study of the friction force. In addition, parameters of a low-energy cooler can be chosen in a manner to reproduce regimes expected in future high-energy operation. Here, we report a set of dedicated experiments in CELSIUS aimed at a detailed study of the magnetized friction force. Some results of the accurate comparison of experimental data with the friction force formulas are presented

  11. Study of the magnetic interaction in nanocrystalline Pr-Fe-Co-Nb-B permanent magnets

    Science.gov (United States)

    Dospial, M.; Plusa, D.; Ślusarek, B.

    2012-03-01

    The magnetic properties of an isotropic, epoxy resin bonded magnets made from Pr-Fe-Co-Nb-B powder were investigated. The magnetization reversal process and magnetic parameters were examined by measurements of the initial magnetization curve, major and minor hysteresis loops and sets of recoil curves. From the initial magnetization curve and the field dependencies of the reversible and irreversible magnetization components derived from the recoil loops it was found that the magnetization reversal process is the combination of the nucleation of reversed domains and pinning of domain walls at the grain boundaries and the reversible rotation of magnetization vector in single domain grains. The interactions between grains were studied by means of δM plots. The nonlinear behavior of δM curve approve that the short range intergrain exchange coupling interactions are dominant in a field up to the sample coercivity. The interaction domains and fine magnetic structure were revealed as the evidence of exchange coupling between soft α-Fe and hard magnetic Nd2Fe14B grains.

  12. Study on a magnetic spiral-type wireless capsule endoscope controlled by rotational external permanent magnet

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Bo, E-mail: yebo@hubu.edu.cn [School of Mechanical Science & Engineering, Huazhong University of Science & Technology, Wuhan 430074 (China); School of Computer Science and Information Engineering, HuBei University, Wuhan 430062 (China); Zhang, Wei [Department of Mechanical Engineering, Hubei University of Automotive Technology, Shiyan 442002 (China); Sun, Zhen-jun [School of Mechanical Science & Engineering, Huazhong University of Science & Technology, Wuhan 430074 (China); Guo, Lin [School of Computer Science and Information Engineering, HuBei University, Wuhan 430062 (China); Deng, Chao [School of Mechanical Science & Engineering, Huazhong University of Science & Technology, Wuhan 430074 (China); Chen, Ya-qi [Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Zhang, Hong-hai [School of Mechanical Science & Engineering, Huazhong University of Science & Technology, Wuhan 430074 (China); Liu, Sheng [School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072 (China)

    2015-12-01

    In this paper, the authors propose rotating an external permanent magnet (EPM) to manipulate the synchronous rotation of a magnetic spiral-type wireless capsule endoscope (WCE), and the synchronous rotation of the WCE is converted to its translational motion in intestinal tract. In order to preliminarily verify the feasibility of this method, a handheld actuator (HA) controlled by micro controller unit, a magnetic spiral-type WCE and a bracket were fabricated, theoretical analysis and simulations about the control distance of this method were performed, and in ex-vivo tests were examined in porcine small intestine to verify the control distance and control performances of this method. It was demonstrated that this method showed good performances in controlling the translational motion of the magnetic spiral-type WCE, and this method has great potential to be used in clinical application. - Highlights: • A new magnetic control method for spiral-type wireless capsule endoscope is proposed. • Wireless capsule endoscope rotates synchronously with external permanent magnet. • The method controls the wireless capsule endoscope well in porcine small intestine. • Long control distance makes the method may be used in future medical application. • Experimental setup has great advantages: high cost performance and easy operation.

  13. Study of the behaviour of magnetic lines after perturbation of a toroidal field with magnetic surfaces

    International Nuclear Information System (INIS)

    Mercier, C.

    1989-02-01

    The effect of a perturbing magnetic field on a field whose magnetic surfaces are tori nested around a closed central line is studied. This perturbation effect creates magnetic islands around surfaces with rational rotational transform. These islands are investigated analytically, which makes it possible to evaluate their size. The resulting turbulence of the medium can then be studied by calculating the interaction of two neighbouring islands

  14. Study of a 900 bending magnet for H- beams

    International Nuclear Information System (INIS)

    Sherman, J.D.; Allison, P.W.

    1979-01-01

    Three different magnetic pole face configurations with field indices not equal to 0 have been studied to minimize second-order magnetic focusing aberrations. One pole face with a substantial second-order magnetic field inhomogeneity reduces the measured aberration coefficient to zero. A calculation using first- and second-order ion optics provides a qualitative explanation for the aberration variations seen in these magnets. The pepper pot emittance measurement technique was used

  15. System and method for heating ferrite magnet motors for low temperatures

    Science.gov (United States)

    Reddy, Patel Bhageerath; El-Refaie, Ayman Mohamed Fawzi; Huh, Kum-Kang

    2017-07-04

    A system and method for heating ferrite permanent magnets in an electrical machine is disclosed. The permanent magnet machine includes a stator assembly and a rotor assembly, with a plurality of ferrite permanent magnets disposed within the stator assembly or the rotor assembly to generate a magnetic field that interacts with a stator magnetic field to produce a torque. A controller of the electrical machine is programmed to cause a primary field current to be applied to the stator windings to generate the stator magnetic field, so as to cause the rotor assembly to rotate relative to the stator assembly. The controller is further programmed to cause a secondary current to be applied to the stator windings to selectively generate a secondary magnetic field, the secondary magnetic field inducing eddy currents in at least one of the stator assembly and the rotor assembly to heat the ferrite permanent magnets.

  16. System and method for heating ferrite magnet motors for low temperatures

    Science.gov (United States)

    Reddy, Patel Bhageerath; El-Refaie, Ayman Mohamed Fawzi; Huh, Kum-Kang

    2018-05-08

    A system and method for heating ferrite permanent magnets in an electrical machine is disclosed. The permanent magnet machine includes a stator assembly and a rotor assembly, with a plurality of ferrite permanent magnets disposed within the stator assembly or the rotor assembly to generate a magnetic field that interacts with a stator magnetic field to produce a torque. A controller of the electrical machine is programmed to cause a primary field current to be applied to the stator windings to generate the stator magnetic field, so as to cause the rotor assembly to rotate relative to the stator assembly. The controller is further programmed to cause a secondary current to be applied to the stator windings to selectively generate a secondary magnetic field, the secondary magnetic field inducing eddy currents in at least one of the stator assembly and the rotor assembly to heat the ferrite permanent magnets.

  17. Apparatus and method for materials processing utilizing a rotating magnetic field

    Science.gov (United States)

    Muralidharan, Govindarajan; Angelini, Joseph A.; Murphy, Bart L.; Wilgen, John B.

    2017-04-11

    An apparatus for materials processing utilizing a rotating magnetic field comprises a platform for supporting a specimen, and a plurality of magnets underlying the platform. The plurality of magnets are configured for rotation about an axis of rotation intersecting the platform. A heat source is disposed above the platform for heating the specimen during the rotation of the plurality of magnets. A method for materials processing utilizing a rotating magnetic field comprises providing a specimen on a platform overlying a plurality of magnets; rotating the plurality of magnets about an axis of rotation intersecting the platform, thereby applying a rotating magnetic field to the specimen; and, while rotating the plurality of magnets, heating the specimen to a desired temperature.

  18. Sensor and method for measuring the areal density of magnetic nanoparticles on a micro-array

    NARCIS (Netherlands)

    2003-01-01

    The present invention relates to a method and a device for magnetic detection of binding of biological molecules on a biochip. A magnetoresistive sensor device for measuring an areal density of magnetic nanoparticles on a micro-array, the magnetic nanoparticles (15) being directly or indirectly

  19. Process optimization and properties of magnetically hard cobalt carbide nanoparticles via modified polyol method

    International Nuclear Information System (INIS)

    Zamanpour, Mehdi; Bennett, Steven P.; Majidi, Leily; Chen, Yajie; Harris, Vincent G.

    2015-01-01

    Highlights: • High-coercivity cobalt carbides were synthesized by polyol method. • No rare earth elements were used during synthesis process. • Process parameters (reaction temperature, precursors’ concentrations, surfactants and reaction duration) were studied/optimized. • Process was scaled-up to synthesis more than 5 g powders per batch. - Abstract: Cobalt carbide magnetic nanoparticles were successfully synthesized via a modified polyol process without using a rare-earth catalyst during the synthesis process. The present results show admixtures of Co 2 C and Co 3 C phases possessing magnetization values exceeding 47 emu/g and coercivity values exceeding 2.3 kOe at room temperature. Moreover, these experiments have illuminated the important role of the reaction temperature, hydroxyl ion concentrations and the reaction duration on the crystallographic structure and magnetic properties of the nanoparticles. The crystallographic structure and particle size of the Co x C nanoparticles were characterized by X-ray diffractometry and scanning electron microscopy. Vibrating sample magnetometry was used to determine magnetic properties. Scale-up of synthesis to more than 5 g per batch was demonstrated with no significant degradation of magnetic properties

  20. Methods for the improvement of electrical insulation in vacuum in the presence of transverse magnetic field

    International Nuclear Information System (INIS)

    Hara, Masanori; Suehiro, Junya; Shigematsu, Hidetaka; Yano, Shinsuke

    1989-01-01

    At present in electrical energy field, aiming at the development and operation of new energy sources for the future, the research on nuclear fusion reactors, MHD electricity generation, and electromagnetic energy storage is in progress, and in ordeer to form strong magnetic fields over wide space, large superconducting magnets are expected to be employed. In these magnets, when exciting current changes, voltage is induced internally, therefore, the operation sequence is deeply related to coil insulation, in pulse operation, coil insulation is one of the important factors determining the rating, and the withstand voltage design against the abnormal voltage at the time of quenching is related to the protection of coils. Therefore, the electrical insulation design of large superconducting magnets is an important subject of study. Their electrical insulation system is the compound system of liquid helium, gaseous helium, vacuum and solid insulators. When a cross magnetic field is applied, insulation breakdown characteristics are aggravated. The mechanism of vacuum insulation breakdown and characteristics, the method of improving withstand voltage using spacers or the electrodes for controlling electric field and so on are reported. (K.I.)

  1. Magnetic properties of α-Fe2O3 nanoparticle synthesized by a new hydrothermal method

    International Nuclear Information System (INIS)

    Giri, S.; Samanta, S.; Maji, S.; Ganguli, S.; Bhaumik, A.

    2005-01-01

    Nanoparticles of α-Fe 2 O 3 have been prepared using a hydrothermal synthesis method in aqueous-organic microemulsion under mild alkaline condition. The condensation reaction was optimized in the presence of a cationic surfactant cetyltrimethylammonium bromide (CTAB). It was found that the size and nature of the α-Fe 2 O 3 nanoparticle strongly depends on the pH, oxalic acid and CTAB as well as tetramethylammonium hydroxide (TMAOH, alkali source) concentrations. The uniformity of the particle size was checked by the transmission electron microscopy while the single phase of the nanocrystalline α-Fe 2 O 3 was characterized using powder X-ray diffraction. The Moessbauer study exhibited a sextet pattern with internal field smaller than that of the bulk counterpart. The temperature variation of magnetization showed a broad maximum at around 125 K while the field-cooled effect of the magnetization showed the branching between the field cooled and zero field cooled magnetization up to 340 K. A large anisotropy has been observed from the analysis of magnetization curve as well as from the large blocking temperature. The estimation of the particle size from the magnetization curve was found to be in close agreement with the TEM results

  2. Process optimization and properties of magnetically hard cobalt carbide nanoparticles via modified polyol method

    Energy Technology Data Exchange (ETDEWEB)

    Zamanpour, Mehdi; Bennett, Steven P. [Center for Microwave Magnetic Materials and Integrated Circuits (CM3IC), Northeastern University, Boston, MA 02115 (United States); Majidi, Leily [Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115 (United States); Chen, Yajie [Center for Microwave Magnetic Materials and Integrated Circuits (CM3IC), Northeastern University, Boston, MA 02115 (United States); Harris, Vincent G. [Center for Microwave Magnetic Materials and Integrated Circuits (CM3IC), Northeastern University, Boston, MA 02115 (United States); Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115 (United States)

    2015-03-15

    Highlights: • High-coercivity cobalt carbides were synthesized by polyol method. • No rare earth elements were used during synthesis process. • Process parameters (reaction temperature, precursors’ concentrations, surfactants and reaction duration) were studied/optimized. • Process was scaled-up to synthesis more than 5 g powders per batch. - Abstract: Cobalt carbide magnetic nanoparticles were successfully synthesized via a modified polyol process without using a rare-earth catalyst during the synthesis process. The present results show admixtures of Co{sub 2}C and Co{sub 3}C phases possessing magnetization values exceeding 47 emu/g and coercivity values exceeding 2.3 kOe at room temperature. Moreover, these experiments have illuminated the important role of the reaction temperature, hydroxyl ion concentrations and the reaction duration on the crystallographic structure and magnetic properties of the nanoparticles. The crystallographic structure and particle size of the Co{sub x}C nanoparticles were characterized by X-ray diffractometry and scanning electron microscopy. Vibrating sample magnetometry was used to determine magnetic properties. Scale-up of synthesis to more than 5 g per batch was demonstrated with no significant degradation of magnetic properties.

  3. Methods of Studying Persons.

    Science.gov (United States)

    Heinemann, Allen W.; Shontz, Franklin C.

    Conventional research strategies typically emphasize behavior-determining tendencies so strongly that the person as a whole is ignored. Research strategies for studying whole persons focus on symbolic structures, formulate specific questions in advance, study persons one at a time, use individualized measures, and regard participants as expert…

  4. NATO Advanced Study Institute on Quantum Magnetism

    CERN Document Server

    Barbara, Bernard; Sawatzky, G; Stamp, P. C. E

    2008-01-01

    This book is based on some of the lectures during the Pacific Institute of Theoretical Physics (PITP) summer school on "Quantum Magnetism", held during June 2006 in Les Houches, in the French Alps. The school was funded jointly by NATO, the CNRS, and PITP, and entirely organized by PITP. Magnetism is a somewhat peculiar research field. It clearly has a quantum-mechanical basis – the microsopic exchange interactions arise entirely from the exclusion principle, in conjunction with respulsive interactions between electrons. And yet until recently the vast majority of magnetism researchers and users of magnetic phenomena around the world paid no attention to these quantum-mechanical roots. Thus, eg., the huge ($400 billion per annum) industry which manufactures hard discs, and other components in the information technology sector, depends entirely on room-temperature properties of magnets - yet at the macroscopic or mesoscopic scales of interest to this industry, room-temperature magnets behave entirely classic...

  5. Magnetic study of nanocrystalline 0.95MnO/0.05ZnO

    International Nuclear Information System (INIS)

    Guskos, N.; Dudek, M.; Zolnierkiewicz, G.; Typek, J.; Berczynski, P.; Lendzion-Bielun, Z.; Sibera, D.; Narkiewicz, U.

    2013-01-01

    Nanocrystalline 0.95MnO/0.05ZnO sample has been prepared by coprecipitation and calcination processes. X-ray diffraction showed the presence of Mn 3 O 4 nanocrystallites with an average size of 43 nm. Magnetic properties of the 0.95MnO/0.05ZnO sample have been investigated by dc magnetization and magnetic resonances (electron paramagnetic resonance (EPR), ferromagnetic resonance (FMR)) methods. The magnetization study has shown the presence of dominating Mn 3 O 4 paramagnetic and ferrimagnetic (below 46 K) phases. The blocking temperature determined from magnetization measurements was 41 K. An FMR study has shown the evidence of the spread of nanoparticles sizes. An EPR signal from paramagnetic phase of Mn 3 O 4 was observed at temperatures above 45 K and from defects/spurious phases in the low temperature range (T<16 K). Magnetic anisotropies of the sample in the FMR spectra were taken into account by fitting the observed spectra by two lines corresponding to parallel and perpendicular orientations of nanoparticles in an applied magnetic field. - Highlights: ► Magnetic properties of 0.95MnO/0.05ZnO have been studied by dc magnetization and magnetic resonance. ► FMR and EPR spectra were identified and attributed to various spin systems. ► From the spread of blocking temperatures obtained from magnetic resonance the spread of nanoparticles sizes was estimated.

  6. Simple method for the generation of multiple homogeneous field volumes inside the bore of superconducting magnets.

    Science.gov (United States)

    Chou, Ching-Yu; Ferrage, Fabien; Aubert, Guy; Sakellariou, Dimitris

    2015-07-17

    Standard Magnetic Resonance magnets produce a single homogeneous field volume, where the analysis is performed. Nonetheless, several modern applications could benefit from the generation of multiple homogeneous field volumes along the axis and inside the bore of the magnet. In this communication, we propose a straightforward method using a combination of ring structures of permanent magnets in order to cancel the gradient of the stray field in a series of distinct volumes. These concepts were demonstrated numerically on an experimentally measured magnetic field profile. We discuss advantages and limitations of our method and present the key steps required for an experimental validation.

  7. Nanodiamond graphitization: a magnetic resonance study

    International Nuclear Information System (INIS)

    Panich, A M; Shames, A I; Sergeev, N A; Olszewski, M; McDonough, J K; Mochalin, V N; Gogotsi, Y

    2013-01-01

    We report on the first nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) study of the high-temperature nanodiamond-to-onion transformation. 1 H, 13 C NMR and EPR spectra of the initial nanodiamond samples and those annealed at 600, 700, 800 and 1800 ° C were measured. For the samples annealed at 600 to 800 ° C, our NMR data reveal the early stages of the surface modification, as well as a progressive increase in sp 2 carbon content with increased annealing temperature. Such quantitative experimental data were recorded for the first time. These findings correlate with EPR data on the sensitivity of the dangling bond EPR line width to air content, progressing with rising annealing temperature, that evidences consequent graphitization of the external layers of the diamond core. The sample annealed at 1800 ° C shows complete conversion of nanodiamond particles into carbon onions. (paper)

  8. Nuclear magnetic resonance studies of biological systems

    International Nuclear Information System (INIS)

    Antypas, W.G. Jr.

    1988-01-01

    The difference between intracellular and extracellular proton relaxation rates provides the basis for the determination of the mean hemoglobin concentration (MHC) in red blood cells. The observed water T 1 relaxation data from red blood cell samples under various conditions were fit to the complete equation for the time-dependent decay of magnetization for a two-compartment system including chemical exchange. The MHC for each sample was calculated from the hematocrit and the intracellular water fraction as determined by NMR. The binding of the phosphorylcholine (PC) analogue, 2-(trimethylphosphonio)-ethylphosphate (phosphoryl-phosphocholine, PPC) to the PC binding myeloma proteins TEPC-15, McPC 603, and MOPC 167 was studied by 31 P NMR

  9. Testing the isotropic boundary algorithms method to evaluate the magnetic field configuration in the tail

    International Nuclear Information System (INIS)

    Sergeev, V.A.; Malkov, M.; Mursula, K.

    1993-01-01

    This paper describes tests done on one model system for studying the magnetic field in the magneotail, called the isotropic boundary algorithm method. The tail field lines map into the ionosphere, and there have been two direct methods applied to study tail fields, one a global model, and the other a local model. The global models are so broad in scope that they have a hard time dealing with specific field configurations at some time and some location. Local models rely upon field measurements being simultaneously available over a large region of space to study simultaneously the field configurations. In general this is either very fortuitous or very expensive. The isotropic boundary algorithm method relys upon measuring energetic particles, here protons with energies greater than 30 keV, in the isotropic boundary at low altitudes and interpreting them as representing the boundary between stochastic and adiabatic particle motion regions in the equatorial tail current sheet. The authors have correlated particle measurements by NOAA spacecraft to study the isotropic boundary, with magnetic measurements of tail magnetic fields by the geostationary GOES 2 spacecraft. Positive correlations are observed

  10. Magnetic susceptibility and magnetization studies of some commercial austenitic stainless steels

    International Nuclear Information System (INIS)

    Collings, E.W.

    1979-01-01

    Results of magnetic susceptibility measurements using the Curie magnetic force technique are reported for six AISI 300-series alloys 310S, 304, 304L, 304N, 316, 316L as well as AWS 330 weld metal and Inconel 625. The temperature ranged from 5 to 416 0 K. Magnetization measurements over the temperature range 3 to 297 0 K, performed using a vibrating-sample magnetometer, are also reported. Alloy compositions and sample preparation procedures are discussed and numerical results of the study are presented. Magnetic characteristics of the four principal types of austenitic stainless steels studied are summarized

  11. Method and apparatus for assembling a permanent magnet pole assembly

    Science.gov (United States)

    Carl, Jr., Ralph James; Bagepalli, Bharat Sampathkumaran [Niskayuna, NY; Jansen, Patrick Lee [Scotia, NY; Dawson, Richard Nils [Voorheesville, NY; Qu, Ronghai [Clifton Park, NY; Avanesov, Mikhail Avramovich [Moscow, RU

    2009-08-11

    A pole assembly for a rotor, the pole assembly includes a permanent magnet pole including at least one permanent magnet block, a plurality of laminations including a pole cap mechanically coupled to the pole, and a plurality of laminations including a base plate mechanically coupled to the pole.

  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. Method of Relative Magnitudes for Calculating Magnetic Fluxes in Electrical Machine

    Directory of Open Access Journals (Sweden)

    Oleg A.

    2018-03-01

    Full Text Available Introduction: The article presents the study results of the model of an asynchronous electric motor carried out by the author within the framework of the Priorities Research Program “Research and development in the priority areas of development of Russia’s scientific and technical complex for 2014–2020”. Materials and Methods: A model of an idealized asynchronous machine (with sinusoidal distribution of magnetic induction in air gap is used in vector control systems. It is impossible to create windings for this machine. The basis of the new calculation approach was the Conductivity of Teeth Contours Method, developed at the Electrical Machines Chair of the Moscow Power Engineering Institute (MPEI. Unlike this method, the author used not absolute values, but relative magnitudes of magnetic fluxes. This solution fundamentally improved the method’s capabilities. The relative magnitudes of the magnetic fluxes of the teeth contours do not required the additional consideration for exact structure of magnetic field of tooth and adjacent slots. These structures are identical for all the teeth of the machine and differ only in magnitude. The purpose of the calculations was not traditional harmonic analysis of magnetic induction distribution in air gap of machine, but a refinement of the equations of electric machine model. The vector control researchers used only the cos(θ function as a value of mutual magnetic coupling coefficient between the windings. Results: The author has developed a way to take into account the design of the windings of a real machine by using imaginary measuring winding with the same winding design as a real phase winding. The imaginary winding can be placed in the position of any machine windings. The calculation of the relative magnetic fluxes of this winding helped to estimate the real values of the magnetic coupling coefficients between the windings, and find the correction functions for the model of an idealized

  14. Apparatus and method for continuous separation of magnetic particles from non-magnetic fluids

    Science.gov (United States)

    Oder, Robin R.; Jamison, Russell E.

    2010-02-09

    A magnetic separator vessel (1) for separating magnetic particles from non-magnetic fluid includes a separation chamber having an interior and exterior wall, a top and bottom portion; a magnet (3) having first and second poles (2) positioned adjacent to the exterior wall, wherein the first pole is substantially diametrically opposed to the second pole; a inlet port (5) is directed into the top portion of the separation chamber, wherein the inlet port (5) is positioned adjacent to one of the first and second poles (2), wherein the inlet port (5) is adapted to transfer a mixture into the separation chamber; an underflow port (6) in communication with the bottom portion, wherein the underflow port (6) is adapted to receive the magnetic particles; and an overflow port (9) in communication with the separation chamber, wherein the overflow port (9) is adapted to receive the non-magnetic fluid.

  15. Mechanism for and method of biasing magnetic sensor

    Science.gov (United States)

    Kautz, David R.

    2007-12-04

    A magnetic sensor package having a biasing mechanism involving a coil-generated, resistor-controlled magnetic field for providing a desired biasing effect. In a preferred illustrated embodiment, the package broadly comprises a substrate; a magnetic sensor element; a biasing mechanism, including a coil and a first resistance element; an amplification mechanism; a filter capacitor element; and an encapsulant. The sensor is positioned within the coil. A current applied to the coil produces a biasing magnetic field. The biasing magnetic field is controlled by selecting a resistance value for the first resistance element which achieves the desired biasing effect. The first resistance element preferably includes a plurality of selectable resistors, the selection of one or more of which sets the resistance value.

  16. Application of Surface Geophysical Methods, With Emphasis on Magnetic Resonance Soundings, to Characterize the Hydrostratigraphy of the Brazos River Alluvium Aquifer, College Station, Texas, July 2006 - A Pilot Study

    Science.gov (United States)

    Shah, Sachin D.; Kress, Wade H.; Legchenko, Anatoly

    2007-01-01

    The U.S. Geological Survey, in cooperation with the Texas Water Development Board, used surface geophysical methods at the Texas A&M University Brazos River Hydrologic Field Research Site near College Station, Texas, in a pilot study, to characterize the hydrostratigraphic properties of the Brazos River alluvium aquifer and determine the effectiveness of the methods to aid in generating an improved ground-water availability model. Three non-invasive surface geophysical methods were used to characterize the electrical stratigraphy and hydraulic properties and to interpret the hydrostratigraphy of the Brazos River alluvium aquifer. Two methods, time-domain electromagnetic (TDEM) soundings and two-dimensional direct-current (2D-DC) resistivity imaging, were used to define the lateral and vertical extent of the Ships clay, the alluvium of the Brazos River alluvium aquifer, and the underlying Yegua Formation. Magnetic resonance sounding (MRS), a recently developed geophysical method, was used to derive estimates of the hydrologic properties including percentage water content and hydraulic conductivity. Results from the geophysics study demonstrated the usefulness of combined TDEM, 2D-DC resistivity, and MRS methods to reduce the need for additional boreholes in areas with data gaps and to provide more accurate information for ground-water availability models. Stratigraphically, the principal finding of this study is the relation between electrical resistivity and the depth and thickness of the subsurface hydrostratigraphic units at the site. TDEM data defined a three-layer electrical stratigraphy corresponding to a conductor-resistor-conductor that represents the hydrostratigraphic units - the Ships clay, the alluvium of the Brazos River alluvium aquifer, and the Yegua Formation. Sharp electrical boundaries occur at about 4 to 6 and 20 to 22 meters below land surface based on the TDEM data and define the geometry of the more resistive Brazos River alluvium aquifer

  17. Magnet design studies for the TRIUMF KAON factory proposal

    International Nuclear Information System (INIS)

    Otter, A.J.; Ellstrom, L.; Haddock, C.; Harold, M.; Reeve, P.; Sasaki, H.; Schwandt, P.

    1989-10-01

    TRIUMF is engaged on a one year Project Definition Study of its KAON factory proposal. This proposal calls for a total of 1800 magnets to be installed in three storage rings, two synchrotrons, beam transfer lines and experimental facilities to increase the present beam from 200 μA at 500 MeV to 100 μA at 30 GeV. The paper discusses the current design status concentrating on the ac booster synchrotron ring magnets which will be driven by biased dc current modulated at 50 Hz. Methods of estimating the core losses for this excitation, the coil eddy current losses and design and fabrication features of prototypes will be presented

  18. Study of biological fluids by nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Kriat, M.; Vion-Dury, J.; Confort-Gouny, S.; Sciaky, M.; Cozzone, P.J.

    1991-01-01

    The use of nuclear magnetic resonance (NMR) spectroscopy in the study of biofluids is rapidly developing and might soon constitute a new major medical application of this technique which benefits from technological and methodological progress such as higher magnetic fields, new probe design, solvent suppression sequences and advanced data processing routines. In this overview, the clinical and pharmacological impact of this new approach is examined, with emphasis on the NMR spectroscopy of plasma, cerebrospinal fluid and urine. Applications to pharmacokinetics and toxicology are illustrated. Interestingly, a number of biochemical components of fluids which are not usually assayed by conventional biochemical methods are readily detected by NMR spectroscopy which is clearly a new competitive entrant among the techniques used in clinical biology. Its ease-of-use, cost effectiveness and high informational content might turn it into a major diagnostic tool in the years to come [fr

  19. A study: Effect of Students Peer Assisted Learning on Magnetic Field Achievement

    International Nuclear Information System (INIS)

    Mueanploy, Wannapa

    2016-01-01

    This study is the case study of Physic II Course for students of Pathumwan Institute of Technology. The purpose of this study is: 1) to develop cooperative learning method of peer assisted learning (PAL), 2) to compare the learning achievement before and after studied magnetic field lesson by cooperative learning method of peer assisted learning. The population was engineering students of Pathumwan Institute of Technology (PIT’s students) who registered Physic II Course during year 2014. The sample used in this study was selected from the 72 students who passed in Physic I Course. The control groups learning magnetic fields by Traditional Method (TM) and experimental groups learning magnetic field by method of peers assisted learning. The students do pretest before the lesson and do post-test after the lesson by 20 items achievement tests of magnetic field. The post-test higher than pretest achievement significantly at 0.01 level. (paper)

  20. Magnetic

    Science.gov (United States)

    Aboud, Essam; El-Masry, Nabil; Qaddah, Atef; Alqahtani, Faisal; Moufti, Mohammed R. H.

    2015-06-01

    The Rahat volcanic field represents one of the widely distributed Cenozoic volcanic fields across the western regions of the Arabian Peninsula. Its human significance stems from the fact that its northern fringes, where the historical eruption of 1256 A.D. took place, are very close to the holy city of Al-Madinah Al-Monawarah. In the present work, we analyzed aeromagnetic data from the northern part of Rahat volcanic field as well as carried out a ground gravity survey. A joint interpretation and inversion of gravity and magnetic data were used to estimate the thickness of the lava flows, delineate the subsurface structures of the study area, and estimate the depth to basement using various geophysical methods, such as Tilt Derivative, Euler Deconvolution and 2D modeling inversion. Results indicated that the thickness of the lava flows in the study area ranges between 100 m (above Sea Level) at the eastern and western boundaries of Rahat Volcanic field and getting deeper at the middle as 300-500 m. It also showed that, major structural trend is in the NW direction (Red Sea trend) with some minor trends in EW direction.

  1. The study on optimization issues for magnetic separation by magnetic chromatography

    International Nuclear Information System (INIS)

    Kim, S.B.; Iwamoto, R.; Kataoka, K.; Noguchi, S.; Okada, H.

    2010-01-01

    The magnetic chromatography is a very useful system for an ion and/or fine magnetic particle separation because it has strong magnetic field gradients even in a very narrow flow channel. We have not only developed the magnetic chromatography system to separate the fine particles and ions, but also the numerical analysis code based on the fluid dynamics and electromagnetism to investigate the separating characteristics and to optimize design of magnetic column. In this study, the simple experiments using a superconducting magnet with a large room-temperature-bore and a micro-scale magnetic column consisting of ferromagnetic wires were carried out to understand the ions separation. The cobalt chloride (CoCl 2 ) and the nickel sulfate (NiSO 4 ) were used as ions, and the magnetic field and length of magnetic column were used as a parameter in an experiment and an analysis. It can be expected that the ion mobility of a single and complex are quite different, and the ability of the separation will be improved by increasing the column length without external magnetic field.

  2. A new method for preparing mono-dispersed nanoparticles using magnetized water

    Science.gov (United States)

    Nakhaei Pour, Ali; Gholizadeh, Mostafa; Housaindokht, Mohammadreza; Moosavi, Fatemeh; Monhemi, Hasan

    2017-04-01

    We studied the use of magnetized water on the size of the nanoparticles. Magnetized water found to reduce the diameter of the nanoparticles during a homogeneous precipitation process, which is a combination of nucleation and nuclei growth processes. We found that the modified water, which demonstrated different physical properties especially on the surface tension and viscosity, significantly influenced the both processes. Therefore, the nucleation process was initially prolonged in the homogeneous precipitation process due to the lower critical size of nucleus and higher rate of nucleation, and consequently formed smaller particles and a larger number of particles. Furthermore, the growth rate of nanoparticles was hindered owing to the higher viscosity of the water and restriction in the mass transport process. As a result, the precipitated particles with the magnetized water were eventually structured smaller particle diameter compared to the bulk. The presented method in here indicated a low cost, straightforward, and feasible technique for industrial application. In addition, this method could open a new promising perspective on nanomaterial synthesis in order to facilitate the production of monodispersed nanoparticles. Molecular dynamic confirmed that surface tension decreased as the external magnetic field was applied. Moreover, the density profile illustrated that the average number of hydrogen atoms is greater than oxygen atoms.

  3. Magnetic study of weakly contaminated forest soils

    Czech Academy of Sciences Publication Activity Database

    Kapička, Aleš; Jordanova, Neli; Petrovský, Eduard; Podrázský, V.

    2003-01-01

    Roč. 148, 1/4 (2003), s. 31-44 ISSN 0049-6979 R&D Projects: GA AV ČR IAA3012905 Institutional research plan: CEZ:AV0Z3012916 Keywords : anthropogenic ferrimagnetics * environmental magnetism * soil pollution Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.883, year: 2003

  4. A magnetic method to concentrate and trap biological targets

    KAUST Repository

    Li, Fuquan

    2012-11-01

    Magnetoresistive sensors in combination with magnetic particles have been used in biological applications due to, e.g., their small size and high sensitivity. A growing interest is to integrate magnetoresistive sensors with microchannels and electronics to fabricate devices that can perform complex analyses. A major task in such systems is to immobilize magnetic particles on top of the sensor surface, which is required to detect the particles\\' stray field. In the presented work, a bead concentrator, consisting of gold microstructures, at the bottom of a microchannel, is used to attract and move magnetic particles into a trap. The trap is made of a chamber with a gold microstructure underneath and is used to attract and immobilize a defined number of magnetic beads. In order to detect targets, two kinds of solutions were prepared; one containing only superparamagnetic particles, the other one containing beads with the protein Bovine serum albumin as the target and fluorescent markers. Due to the size difference between bare beads and beads with target, less magnetic beads were immobilized inside the volume chamber in case of magnetic beads with target as compared to bare magnetic beads. © 1965-2012 IEEE.

  5. A contribution to the study of superconducting magnets

    International Nuclear Information System (INIS)

    Ciazynski, D.

    1983-09-01

    The protection study of a Nb 3 Sn superconducting magnet with high current density brought new information on the calculus of maximum temperature in the coil, the longitudinal and transversal propagation velocity of the normal zone. It has finally led to realization and using as protection device of a superconducting switch allowing to rapidly ''open'' the feeding circuit of the magnet and of a secondary circuit magnetically coupled to the magnet to accelerate the decreasing of the current without increasing the maximum voltage at the magnet connections [fr

  6. Resonance magnetic x-ray scattering study of erbium

    DEFF Research Database (Denmark)

    Sanyal, M.K.; Gibbs, D.; Bohr, J.

    1994-01-01

    The magnetic phases of erbium have been studied by resonance x-ray-scattering techniques. When the incident x-ray energy is tuned near the L(III) absorption edge, large resonant enhancements of the magnetic scattering are observed above 18 K. We have measured the energy and polarization dependence...... of this magnetic scattering and analyzed it using a simple model based on electric dipole and quadrupole transitions among atomic orbitals. The line shapes can be fitted to a magnetic structure combining both c-axis-modulated and basal-plane components. Below 18 K, we have observed unusual behavior of the magnetic...

  7. FC and ZFC magnetic properties of ferro-spinels (MFe2O4) prepared by solution-combustion method

    Science.gov (United States)

    Aravind, G.; Kumar, R. Vijaya; Nathaniyal, V.; Rambabu, T.; Ravinder, D.

    2017-07-01

    Magnetic ferro-spinels MFe2O4 (M= Co and Ni) prepared by citrate-gel solution combustion method using metal nitrates with low sintering temperature (500°C). From the XRD and TEM studies confirm that a nano crystalline nature of the prepared samples. Field Cooled (FC) and Zero Field Cooled (ZFC) magnetic studies of the prepared ferro-spinels are measured by using vibrating sample magnetometer (VSM). The resultant magnetization of the prepared samples as a function of an applied magnetic field 10 T was measured at two different temperatures 5 K and 310 K. Field Cooled (FC) and Zero Field Cooled (ZFC) magnetization measurements under an applied field of 100 Oe and 1000 Oe in the temperature range of 5-375 K were carried out, which shows the blocking temperature of these two samples at around 350 K.

  8. Method of formation of a high gradient magnetic field and the device for division of substances

    International Nuclear Information System (INIS)

    Il'yashenko, E. I.; Glebov, V. A.; Skeltorp, A. T.

    2005-01-01

    Full text: The method and the device [1] are intended for use as a high-sensitivity magnetic separator for different types of paramagnetic substances and materials from diamagnetic ones, for division of paramagnetic substances and materials on the magnitudes of their paramagnetic susceptibility, for division of diamagnetic substances and materials on magnitudes of their diamagnetic susceptibility. Scopes: to produce pure and super pure substances and materials in electronics, metallurgy and chemistry, separation of biological objects (red blood cells, magnetic bacteria, etc.) in biology and medicine, water treatment removing heavy metals and organic impurities, etc. The main condition for magnetic separation is the magnetic force which acts on a particle of the substance and which is proportional to the magnetic susceptibility of the substance, magnetic induction B and gradient ∇B of the applied magnetic field. Therefore, to increase the sensitivity and selectivity of magnetic separation it will be required to use the largest possible values of the magnetic induction and the gradient of a magnetic field, or their product - B∇B. The device declared in the present work includes the magnetic system such as the open domain structure, consisting of permanent magnets with magnetic anisotropy much greater than the induction of a material of magnets. However, the declared device differs from the open domain structure in that [1]: *the surface of the neighbor poles of magnets is covered with a mask made from sheets of adjustable thickness of a soft magnetic material; *the soft magnetic material of the mask is selected on the basis of the magnitudes of the induction of saturation and magnetic permeability for achievement of the required magnitude of the induction and gradient of the magnetic field; *between the sheets of the mask there is an adjustable gap located symmetrically relative to the junction line of the magnets; *the size and the form of the gap between the

  9. Methods for Computing Accurate Atomic Spin Moments for Collinear and Noncollinear Magnetism in Periodic and Nonperiodic Materials.

    Science.gov (United States)

    Manz, Thomas A; Sholl, David S

    2011-12-13

    The partitioning of electron spin density among atoms in a material gives atomic spin moments (ASMs), which are important for understanding magnetic properties. We compare ASMs computed using different population analysis methods and introduce a method for computing density derived electrostatic and chemical (DDEC) ASMs. Bader and DDEC ASMs can be computed for periodic and nonperiodic materials with either collinear or noncollinear magnetism, while natural population analysis (NPA) ASMs can be computed for nonperiodic materials with collinear magnetism. Our results show Bader, DDEC, and (where applicable) NPA methods give similar ASMs, but different net atomic charges. Because they are optimized to reproduce both the magnetic field and the chemical states of atoms in a material, DDEC ASMs are especially suitable for constructing interaction potentials for atomistic simulations. We describe the computation of accurate ASMs for (a) a variety of systems using collinear and noncollinear spin DFT, (b) highly correlated materials (e.g., magnetite) using DFT+U, and (c) various spin states of ozone using coupled cluster expansions. The computed ASMs are in good agreement with available experimental results for a variety of periodic and nonperiodic materials. Examples considered include the antiferromagnetic metal organic framework Cu3(BTC)2, several ozone spin states, mono- and binuclear transition metal complexes, ferri- and ferro-magnetic solids (e.g., Fe3O4, Fe3Si), and simple molecular systems. We briefly discuss the theory of exchange-correlation functionals for studying noncollinear magnetism. A method for finding the ground state of systems with highly noncollinear magnetism is introduced. We use these methods to study the spin-orbit coupling potential energy surface of the single molecule magnet Fe4C40H52N4O12, which has highly noncollinear magnetism, and find that it contains unusual features that give a new interpretation to experimental data.

  10. Tools and methods for teaching magnetic resonance concepts and techniques

    DEFF Research Database (Denmark)

    Hanson, Lars G.

    2012-01-01

    Teaching of MRI methodology can be challenging for teachers as well as students. To support student learning, two graphical simulators for exploration of basic magnetic resonance principles are here introduced. The first implements a simple compass needle analogy implemented for day one of NMR...... and MRI education. After a few minutes of use, any user with minimal experience of magnetism will be able to explain the basic magnetic resonance principle. A second piece of software, the Bloch Simulator, aims much further, as it can be used to demonstrate and explore a wide range of phenomena including...

  11. Canonical Transform Method for Treating Strongly Anisotropy Magnets

    DEFF Research Database (Denmark)

    Cooke, J. F.; Lindgård, Per-Anker

    1977-01-01

    An infinite-order perturbation approach to the theory of magnetism in magnets with strong single-ion anisotropy is given. This approach is based on a canonical transformation of the system into one with a diagonal crystal field, an effective two-ion anisotropy, and reduced ground-state corrections....... A matrix-element matching procedure is used to obtain an explicit expression for the spin-wave energy to second order. The consequences of this theory are illustrated by an application to a simple example with planar anisotropy and an external magnetic field. A detailed comparison between the results...

  12. study of the magnetic field of the MGC-20 cyclotron accelerator magent

    International Nuclear Information System (INIS)

    Gad, K.M.M.

    2007-01-01

    studies of the magent of the MGC-20 cyclotron were carried out. measurements of the magnetic field were done in the cyclotron project, EAEA. calculations of the magnetic field were carried out using Poisson's 2D code, which was developed in Los Alamos laboratories in the USA. we developed a new calculation method for the magnetic field which is the independent layer method. a comparison between the measured and the calculated values for the magnetic field was done, we found good agreement between them, also we calculated the averaged magnetic field and found that the calculations show good isochronous magnetic field which is important in the focusing of the ion beam . study of the poisson code is presented as a target of the master plane to have a good understanding of the code as a step to develop the program or to do another one, this new calculation method proved to give good results for the magnetic field of a complicated magnet such as that of the MGC-20 magnet

  13. Application of an analytical method for the field calculation in superconducting magnets

    International Nuclear Information System (INIS)

    Martinelli, G.; Morini, A.

    1983-01-01

    Superconducting magnets are taking on ever-growing importance due to their increasing prospects of utilization in electrical machines, nuclear fusion, MHD conversion and high-energy physics. These magnets are generally composed of cylindrical or saddle coils, while a ferromagnetic shield is generally situated outside them. This paper uses an analytical method for calculating the magnetic field at every point in a superconducting magnet composed of cylindrical or saddle coils. The method takes into account the real lengths and finite thickness of the coils as well as their radial and axial ferromagnetic shields, if present. The values and distribution of the flux density for some superconducting magnets of high dimensions and high magnetic field, composed of cylindrical or saddle coils, are also given. The results obtained with analytical method are compared with those obtained using numerical methods

  14. Method for the detection of a magnetic field utilizing a magnetic vortex

    Science.gov (United States)

    Novosad, Valentyn [Chicago, IL; Buchanan, Kristen [Batavia, IL

    2010-04-13

    The determination of the strength of an in-plane magnetic field utilizing one or more magnetically-soft, ferromagnetic member, having a shape, size and material whereas a single magnetic vortex is formed at remanence in each ferromagnetic member. The preferred shape is a thin circle, or dot. Multiple ferromagnetic members can also be stacked on-top of each other and separated by a non-magnetic spacer. The resulting sensor is hysteresis free. The sensor's sensitivity, and magnetic saturation characteristics may be easily tuned by simply altering the material, size, shape, or a combination thereof to match the desired sensitivity and saturation characteristics. The sensor is self-resetting at remanence and therefore does not require any pinning techniques.

  15. Finite perturbation studies of magnetic susceptibility and shielding with GIAO

    International Nuclear Information System (INIS)

    Zaucer, M.; Pumpernik, D.; Hladnik, M.; Azman, A.

    1977-01-01

    The magnetic susceptibility tensor and proton and fluorine magnetic shielding tensors are calculated for F 2 and (FHF) - using an ab initio finite perturbation method with gauge-invariant atomic orbitals (GIAO). The discussion of the basis set deficiency shows that the calculated values for the susceptibilities are reliable. Simple additivity (Pascal rule) for the susceptibility is confirmed. (orig.) [de

  16. Moving grids for magnetic reconnection via Newton-Krylov methods

    KAUST Repository

    Yuan, Xuefei; Jardin, Stephen C.; Keyes, David E.

    2011-01-01

    This paper presents a set of computationally efficient, adaptive grids for magnetic reconnection phenomenon where the current density can develop large gradients in the reconnection region. Four-field extended MagnetoHydroDynamics (MHD) equations

  17. A magnetic method to concentrate and trap biological targets

    KAUST Repository

    Li, Fuquan; Kosel, Jü rgen

    2012-01-01

    Magnetoresistive sensors in combination with magnetic particles have been used in biological applications due to, e.g., their small size and high sensitivity. A growing interest is to integrate magnetoresistive sensors with microchannels

  18. A biodetection method using magnetic particles and micro traps

    KAUST Repository

    Li, Fuquan; Giouroudi, Ioanna; Kosel, Jü rgen

    2012-01-01

    The general working principle of magnetoresistive sensors for biological applications is to specifically attach bioanalytesto magnetic particles and then detect the particles that are immobilized on the sensor surface. The immobilization

  19. Study on industrial wastewater treatment using superconducting magnetic separation

    Science.gov (United States)

    Zhang, Hao; Zhao, Zhengquan; Xu, Xiangdong; Li, Laifeng

    2011-06-01

    The mechanism of industrial wastewater treatment using superconducting magnetic separation is investigated. Fe 3O 4 nanoparticles were prepared by liquid precipitation and characterized by X-ray diffraction (XRD). Polyacrylic acid (PAA) film was coated on the magnetic particles using plasma coating technique. Transmission electron microscope (TEM) observation and infrared spectrum measurement indicate that the particle surface is well coated with PAA, and the film thickness is around 1 nm. Practical paper factory wastewater treatment using the modified magnetic seeds in a superconducting magnet (SCM) was carried out. The results show that the maximum removal rate of chemical oxygen demand (COD) by SCM method can reach 76%.

  20. A study on the changes in attractive force of magnetic attachments for overdenture.

    Science.gov (United States)

    Leem, Han-Wool; Cho, In-Ho; Lee, Jong-Hyuk; Choi, Yu-Sung

    2016-02-01

    Although magnetic attachment is used frequently for overdenture, it is reported that attractive force can be decreased by abrasion and corrosion. The purpose of this study was to establish the clinical basis about considerations and long term prognosis of overdenture using magnetic attachments by investigating the change in attractive force of magnetic attachment applied to the patients. Among the patients treated with overdenture using magnetic attachments in Dankook University Dental Hospital, attractive force records of 61 magnetic attachments of 20 subjects who re-visited from July 2013 to June 2014 were analyzed. Dental magnet tester (Aichi Micro Intelligent Co., Aichi, Japan) was used for measurement. The magnetic attachments used in this study were Magfit IP-B Flat, Magfit DX400, Magfit DX600 and Magfit DX800 (Aichi Steel Co., Aichi, Japan) filled with Neodymium (NdFeB), a rare-earth magnet. Reduction ratio of attractive force had no significant correlation with conditional variables to which attachments were applied, and was higher when the maintenance period was longer (Pattractive force was significantly higher in the subject group in which attachments were used over 9 years than within 9 years (PAttractive force of magnetic attachment is maintained regardless of conditional variables and reduction ratio increased as the maintenance period became longer. Further study on adhesive material, attachment method and design improvement to prevent detachment of magnetic attachment is needed.

  1. The study of magnetic properties and relaxation processes in Co/Au bimetallic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hrubovčák, Pavol [Department of Condensed Matter Physics, P.J. Šafárik University, Park Angelinum 9, Košice (Slovakia); Zeleňáková, Adriana, E-mail: adriana.zelenakova@upjs.sk [Department of Condensed Matter Physics, P.J. Šafárik University, Park Angelinum 9, Košice (Slovakia); Zeleňák, Vladimir [Department of Inorganic Chemistry, P.J. Šafárik University, Moyzesova 11, Košice (Slovakia); Kováč, Jozef [Institute of Experimental Physics, SAS, Watsonova 41, Košice (Slovakia)

    2015-11-15

    Co/Au bimetallic fine nanoparticles were prepared employing the method of microemulsion using reverse micelle as nanoreactor, controlling the particles size. Magnetic and structural properties of two different samples Co/Au1 and Co/Au2 with almost comparable size of Co core and different size of Au layer were studied. The investigation of magnetic relaxation processes present in the particles was carried out by means of ac and dc magnetization data obtained at different temperatures and magnitudes of magnetic field. We observed the existence of superspin glass state characterized by the strong inter-particle interactions in the nanoparticle systems. In this paper, we discuss the attributes of novel superspin glass magnetic state reflected on various features (saturated FC magnetization at low temperatures, shift of the Cole–Cole arc downwards) and calculated parameters (relaxation time, critical exponent zv ∼ 10 and frequency dependent criterion p < 0.05). Comparison of the magnetic properties of two studied samples show that the thickness of diamagnetic Au shell significantly influences the magnetic interactions and change the relaxation dynamics. - Highlights: • Co/Au fine nanoparticles prepared by reverse micelle as nanoreactor, controlling the size. • Existence of superspin glass state confirmed from ac magnetic susceptibility study. • Individual particles exhibit the collective behavior below glass temperature T{sub SSG}. • Influence of diamagnetic shell on the magnetic properties of core–shell nanoparticles.

  2. An analytical-numerical comprehensive method for optimizing the fringing magnetic field

    International Nuclear Information System (INIS)

    Xiao Meiqin; Mao Naifeng

    1991-01-01

    The criterion of optimizing the fringing magnetic field is discussed, and an analytical-numerical comprehensive method for realizing the optimization is introduced. The method mentioned above consists of two parts, the analytical part calculates the field of the shims, which corrects the fringing magnetic field by using uniform magnetizing method; the numerical part fulfils the whole calculation of the field distribution by solving the equation of magnetic vector potential A within the region covered by arbitrary triangular meshes with the aid of finite difference method and successive over relaxation method. On the basis of the method, the optimization of the fringing magnetic field for a large-scale electromagnetic isotope separator is finished

  3. Magnetic force microscopy method and apparatus to detect and image currents in integrated circuits

    Science.gov (United States)

    Campbell, Ann. N.; Anderson, Richard E.; Cole, Jr., Edward I.

    1995-01-01

    A magnetic force microscopy method and improved magnetic tip for detecting and quantifying internal magnetic fields resulting from current of integrated circuits. Detection of the current is used for failure analysis, design verification, and model validation. The interaction of the current on the integrated chip with a magnetic field can be detected using a cantilevered magnetic tip. Enhanced sensitivity for both ac and dc current and voltage detection is achieved with voltage by an ac coupling or a heterodyne technique. The techniques can be used to extract information from analog circuits.

  4. Magnetic design and method of a superconducting magnet for muon g - 2/EDM precise measurements in a cylindrical volume with homogeneous magnetic field

    Science.gov (United States)

    Abe, M.; Murata, Y.; Iinuma, H.; Ogitsu, T.; Saito, N.; Sasaki, K.; Mibe, T.; Nakayama, H.

    2018-05-01

    A magnetic field design method of magneto-motive force (coil block (CB) and iron yoke) placements for g - 2/EDM measurements has been developed and a candidate placements were designed under superconducting limitations of current density 125 A/mm2 and maximum magnetic field on CBs less than 5.5 T. Placements of CBs and an iron yoke with poles were determined by tuning SVD (singular value decomposition) eigenmode strengths. The SVD was applied on a response matrix from magneto-motive forces to the magnetic fields in the muon storage region and two-dimensional (2D) placements of magneto-motive forces were designed by tuning the magnetic field eigenmode strengths obtained by the magnetic field. The tuning was performed iteratively. Magnetic field ripples in the azimuthal direction were minimized for the design. The candidate magnetic design had five CBs and an iron yoke with center iron poles. The magnet satisfied specifications of homogeneity (0.2 ppm peak-to-peak in 2D placements (the cylindrical coordinate of the radial position R and axial position Z) and less than 1.0 ppm ripples in the ring muon storage volume (0.318 m 0.0 m) for the spiral muon injection from the iron yoke at top.

  5. Quantitative Study on Corrosion of Steel Strands Based on Self-Magnetic Flux Leakage

    Directory of Open Access Journals (Sweden)

    Runchuan Xia

    2018-05-01

    Full Text Available This paper proposed a new computing method to quantitatively and non-destructively determine the corrosion of steel strands by analyzing the self-magnetic flux leakage (SMFL signals from them. The magnetic dipole model and three growth models (Logistic model, Exponential model, and Linear model were proposed to theoretically analyze the characteristic value of SMFL. Then, the experimental study on the corrosion detection by the magnetic sensor was carried out. The setup of the magnetic scanning device and signal collection method were also introduced. The results show that the Logistic Growth model is verified as the optimal model for calculating the magnetic field with good fitting effects. Combined with the experimental data analysis, the amplitudes of the calculated values (BxL(x,z curves agree with the measured values in general. This method provides significant application prospects for the evaluation of the corrosion and the residual bearing capacity of steel strand.

  6. Magnet system studies for the Zeus experiment

    International Nuclear Information System (INIS)

    Baynham, D.E.; Coombs, R.C.; Uden, C.N.

    1985-11-01

    The ZEUS experiment will be mounted at the HERA accelerator complex currently under construction at DESY, Hamburg. A large volume of magnetic field will be required for charge selection of particles and track fitting. Two superconducting magnet systems which meet the parameters of the ZEUS Experiment are described; a small solenoid with good radiation transparency and a large aperture Helmholtz coil configuration. Basic design concepts and parameters are presented. (author)

  7. A finite element method for calculating the 3-dimensional magnetic fields of cyclotron

    International Nuclear Information System (INIS)

    Zhao Xiaofeng

    1986-01-01

    A series of formula of the finite element method (scalar potential) for calculating the three-dimensional magnetic field of the main magnet of a sector focused cyclotron, and the realization method of the periodic boundary conditions in the code are given

  8. Disk-cylinder method for using NMR to measure magnetic susceptibility

    International Nuclear Information System (INIS)

    Burnham, A.K.

    1978-01-01

    The sphere-cylinder method of using nuclear magnetic resonance (NMR) to measure the magnetic susceptibility of diamagnetic and paramagnetic materials has been generalized to the disk-cylinder method. A two-fold increase in sensitivity was obtained. Accuracies of 0.1% of the diamagnetism of water should be readily obtainable

  9. Method and apparatus for steady-state magnetic measurement of poloidal magnetic field near a tokamak plasma

    Science.gov (United States)

    Woolley, Robert D.

    1998-01-01

    A method and apparatus for the steady-state measurement of poloidal magnetic field near a tokamak plasma, where the tokamak is configured with respect to a cylindrical coordinate system having z, phi (toroidal), and r axes. The method is based on combining the two magnetic field principles of induction and torque. The apparatus includes a rotor assembly having a pair of inductive magnetic field pickup coils which are concentrically mounted, orthogonally oriented in the r and z directions, and coupled to remotely located electronics which include electronic integrators for determining magnetic field changes. The rotor assembly includes an axle oriented in the toroidal direction, with the axle mounted on pivot support brackets which in turn are mounted on a baseplate. First and second springs are located between the baseplate and the rotor assembly restricting rotation of the rotor assembly about its axle, the second spring providing a constant tensile preload in the first spring. A strain gauge is mounted on the first spring, and electronic means to continually monitor strain gauge resistance variations is provided. Electronic means for providing a known current pulse waveform to be periodically injected into each coil to create a time-varying torque on the rotor assembly in the toroidal direction causes mechanical strain variations proportional to the torque in the mounting means and springs so that strain gauge measurement of the variation provides periodic magnetic field measurements independent of the magnetic field measured by the electronic integrators.

  10. Optimization of Linear Permanent Magnet (PM Generator with Triangular-Shaped Magnet for Wave Energy Conversion using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Aamir Hussain

    2016-06-01

    Full Text Available This paper presents the design optimization of linear permanent magnet (PM generator for wave energy conversion using finite element method (FEM. A linear PM generator with triangular-shaped magnet is proposed, which has higher electromagnetic characteristics, superior performance and low weight as compared to conventional linear PM generator with rectangular shaped magnet. The Individual Parameter (IP optimization technique is employed in order to optimize and achieve optimum performance of linear PM generator. The objective function, optimization variables; magnet angle,M_θ(∆ (θ, the pole-width ratio, P_w ratio(τ_p/τ_mz,, and split ratio between translator and stator, δ_a ratio(R_m/R_e, and constraints are defined. The efficiency and its main parts; copper and iron loss are computed using time-stepping FEM. The optimal values after optimization are presented which yields highest efficiency. Key

  11. The method of projected characteristics for the evolution of magnetic arches

    Science.gov (United States)

    Nakagawa, Y.; Hu, Y. Q.; Wu, S. T.

    1987-01-01

    A numerical method of solving fully nonlinear MHD equation is described. In particular, the formulation based on the newly developed method of projected characteristics (Nakagawa, 1981) suitable to study the evolution of magnetic arches due to motions of their foot-points is presented. The final formulation is given in the form of difference equations; therefore, the analysis of numerical stability is also presented. Further, the most important derivation of physically self-consistent, time-dependent boundary conditions (i.e. the evolving boundary equations) is given in detail, and some results obtained with such boundary equations are reported.

  12. Effect of the double-counting functional on the electronic and magnetic properties of half-metallic magnets using the GGA+U method

    International Nuclear Information System (INIS)

    Tsirogiannis, Christos; Galanakis, Iosif

    2015-01-01

    Methods based on the combination of the usual density functional theory (DFT) codes with the Hubbard models are widely used to investigate the properties of strongly correlated materials. Using first-principle calculations we study the electronic and magnetic properties of 20 half-metallic magnets performing self-consistent GGA+U calculations using both the atomic-limit (AL) and around-mean-field (AMF) functionals for the double counting term, used to subtract the correlation part from the DFT total energy, and compare these results to the usual generalized-gradient-approximation (GGA) calculations. Overall the use of AMF produces results similar to the GGA calculations. On the other hand the effect of AL is diversified depending on the studied material. In general the AL functional produces a stronger tendency towards magnetism leading in some cases to unphysical electronic and magnetic properties. Thus the choice of the adequate double-counting functional is crucial for the results obtained using the GGA+U method. - Highlights: • Ab initio study of half-metallic magnets. • Role of electronic correlations. • Double-counting term. • Atomic-limit vs around-mean-field functionals

  13. Development of methods for body composition studies

    International Nuclear Information System (INIS)

    Mattsson, Soeren; Thomas, Brian J

    2006-01-01

    This review is focused on experimental methods for determination of the composition of the human body, its organs and tissues. It summarizes the development and current status of fat determinations from body density, total body water determinations through the dilution technique, whole and partial body potassium measurements for body cell mass estimates, in vivo neutron activation analysis for body protein measurements, dual-energy absorptiometry (DEXA), computed tomography (CT) and magnetic resonance imaging (MRI, fMRI) and spectroscopy (MRS) for body composition studies on tissue and organ levels, as well as single- and multiple-frequency bioimpedance (BIA) and anthropometry as simple easily available methods. Methods for trace element analysis in vivo are also described. Using this wide range of measurement methods, together with gradually improved body composition models, it is now possible to quantify a number of body components and follow their changes in health and disease. (review)

  14. Development of methods for body composition studies

    Energy Technology Data Exchange (ETDEWEB)

    Mattsson, Soeren [Department of Radiation Physics, Lund University, Malmoe University Hospital, SE-205 02 Malmoe (Sweden); Thomas, Brian J [School of Physical and Chemical Sciences, Queensland University of Technology, Brisbane, QLD 4001 (Australia)

    2006-07-07

    This review is focused on experimental methods for determination of the composition of the human body, its organs and tissues. It summarizes the development and current status of fat determinations from body density, total body water determinations through the dilution technique, whole and partial body potassium measurements for body cell mass estimates, in vivo neutron activation analysis for body protein measurements, dual-energy absorptiometry (DEXA), computed tomography (CT) and magnetic resonance imaging (MRI, fMRI) and spectroscopy (MRS) for body composition studies on tissue and organ levels, as well as single- and multiple-frequency bioimpedance (BIA) and anthropometry as simple easily available methods. Methods for trace element analysis in vivo are also described. Using this wide range of measurement methods, together with gradually improved body composition models, it is now possible to quantify a number of body components and follow their changes in health and disease. (review)

  15. Symmetry analysis in neutron diffraction studies of magnetic structures. IV

    International Nuclear Information System (INIS)

    Izyumov, Yu.A.; Naish, V.E.; Petrov, S.B.

    1979-01-01

    By analyzing the exchange Hamiltonian, the authors develop the technique of determining the magnetic structures liable to occur in a crystal. The technique rests on Bertaut's idea that the exchange eigenfunction corresponds to some magnetic structure. A technically simple and efficient method of diagonalizing the exchange matrix is worked out using the devices of space group representation theory. A method is presented to find the magnetic structures with equal exchange energy (exchange multiplets). The occcurrence of exchange multiplets results from the additional invariance of the exchange Hamiltonian under rotation of all the spins. The degeneracy within the exchange multiplet may be the reason why some magnetic structures arise not according to one irreducible representation of the space group. The theory is illustrated with reference to an example of the magnetic structure of spinels. (Auth.)

  16. Construction of microscale structures in enclosed microfluidic networks by using a magnetic beads based method.

    Science.gov (United States)

    Wang, Zhenyu; Zhang, Xiaojuan; Yang, Jun; Yang, Zhong; Wan, Xiaoping; Hu, Ning; Zheng, Xiaolin

    2013-08-20

    A large number of microscale structures have been used to elaborate flowing control or complex biological and chemical reaction on microfluidic chips. However, it is still inconvenient to fabricate microstructures with different heights (or depths) on the same substrate. These kinds of microstructures can be fabricated by using the photolithography and wet-etching method step by step, but involves time-consuming design and fabrication process, as well as complicated alignment of different masters. In addition, few existing methods can be used to perform fabrication within enclosed microfluidic networks. It is also difficult to change or remove existing microstructures within these networks. In this study, a magnetic-beads-based approach is presented to build microstructures in enclosed microfluidic networks. Electromagnetic field generated by microfabricated conducting wires (coils) is used to manipulate and trap magnetic beads on the bottom surface of a microchannel. These trapped beads are accumulated to form a microscale pile with desired shape, which can adjust liquid flow, dock cells, modify surface, and do some other things as those fabricated microstructures. Once the electromagnetic field is changed, trapped beads may form new shapes or be removed by a liquid flow. Besides being used in microfabrication, this magnetic-beads-based method can be used for novel microfluidic manipulation. It has been validated by forming microscale dam structure for cell docking and modified surface for cell patterning, as well as guiding the growth of neurons. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Thermo-magneto-elastoplastic coupling model of metal magnetic memory testing method for ferromagnetic materials

    Science.gov (United States)

    Shi, Pengpeng; Zhang, Pengcheng; Jin, Ke; Chen, Zhenmao; Zheng, Xiaojing

    2018-04-01

    Metal magnetic memory (MMM) testing (also known as micro-magnetic testing) is a new non-destructive electromagnetic testing method that can diagnose ferromagnetic materials at an early stage by measuring the MMM signal directly on the material surface. Previous experiments have shown that many factors affect MMM signals, in particular, the temperature, the elastoplastic state, and the complex environmental magnetic field. However, the fact that there have been only a few studies of either how these factors affect the signals or the physical coupling mechanisms among them seriously limits the industrial applications of MMM testing. In this paper, a nonlinear constitutive relation for a ferromagnetic material considering the influences of temperature and elastoplastic state is established under a weak magnetic field and is used to establish a nonlinear thermo-magneto-elastoplastic coupling model of MMM testing. Comparing with experimental data verifies that the proposed theoretical model can accurately describe the thermo-magneto-elastoplastic coupling influence on MMM signals. The proposed theoretical model can predict the MMM signals in a complex environment and so is expected to provide a theoretical basis for improving the degree of quantification in MMM testing.

  18. An optimizing design method for a compact iron shielded superconducting magnet for use in MRI

    International Nuclear Information System (INIS)

    Tang Xin; Zu Donglin; Wang Tao; Han Baohui

    2010-01-01

    A method is developed for designing a special iron shielded superconducting magnet for MRI in this paper. The shield is designed as an integral part of the cryostat and high permeability and high saturated magnetization iron material is adopted. This scheme will result in a compact iron shielded magnet. In the presented design, the finite element (FE) method is adopted to calculate the magnetic field produced by superconducting coils and nonlinear iron material. The FE method is incorporated into the simulated annealing method which is employed for corresponding optimization. Therefore, geometrical configurations of both coils and iron shield can be optimized together. This method can deal with discrete design variables which are defined to describe the cable arrangements of coil cross sections. A detailed algorithm of the present design is described and an example for designing a 1.5 T clinical iron shielded magnet for MRI is shown.

  19. Application of magnetic methods for assessment of soil restoration in the vicinity of metallurgical copper-processing plant in Bulgaria.

    Science.gov (United States)

    Jordanova, N; Petrovský, E; Kapicka, A; Jordanova, D; Petrov, P

    2017-04-01

    Copper ore mining and processing are among the most harmful anthropogenic influences for the environment and they are a subject of international and national law regulations. Recultivation of areas influenced by mining and processing industry is commonly applied and monitored in order to restore as much as possible the natural environment. In this study, environmental magnetic methods are applied in order to assess the degree of soil restoration in terms of soil development, after remediation of waste dump from Cu-processing plant. Soils developed under birch forest stands of different age (5, 15, and 25 years) as well as raw waste material were sampled along depth down to 20-30 cm. Variations in magnetic parameters and ratios obtained (magnetic susceptibility, frequency-dependent magnetic susceptibility, anhysteretic remanence (ARM), isothermal remanence (IRM), ARM/IRM 100mT ) suggest the presence of magnetic enhancement in the upper 0-15 cm, the thickness of this layer varying depending on the age of the forest stand. Magnetic mineral responsible for this enhancement is of magnetite type, while waste material contains a large amount of hematite, as evidenced by coercivity analysis of IRM acquisition curves and thermal demagnetization of composite IRM. Magnetic grain-sized proxy parameters suggest that magnetite particles are coarser, magnetically stable, while no or minor amount of superparamagnetic grains were detected at room temperature. A well-defined linear regression between the topsoil magnetic susceptibility and the approximate age of the forest stand provides an indication that the magnetic enhancement is of pedogenic origin. It is concluded that the observed magnetic enhancement of recultivated soils studied is linked to a combined effect of pedogenic contribution and possible additions of industrial ashes as a liming agent for soil restoration.

  20. [Multiple coil pulsed magnetic resonance method to measure the SSC bending magnet multipole moments

    International Nuclear Information System (INIS)

    Clark, W.G.

    1990-01-01

    The main emphasis has been to continue development of the high frequency (to 300 MHz) instrumentation, to test the system on a prototype bending magnet, construct the high frequency 32-channel electronics and probes, to seek industrial partners for technology transfer and commercial exploitation, and to do computer simulations for optimizing design parameters. Experience gained from tests made on a dipole magnet at Lawrence Berkeley Laboratory was extremely valuable and has resulted in substantial modifications to the original design

  1. Role of chelates in magnetic resonance imaging studies

    Directory of Open Access Journals (Sweden)

    Tripathi Laxmi

    2009-01-01

    Full Text Available Imaging studies are tests performed with a variety of techniques that produce pictures of the inside of a patient′s body. Magnetic resonance imaging (MRI is an imaging technique based on the principles of nuclear magnetic resonance. MRI uses a powerful magnetic field, radio waves, and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal body structures. Chelates have a wide application in such imaging techniques. Chelates in imaging studies are used alone as radioactive agents or conjugated to monoclonal antibodies or to DNA as radioactive agents. Technetium chelates and gadolinium chelates are being widely used as magnetic resonance contrast media.

  2. 77 FR 51046 - Certain Sintered Rare Earth Magnets, Methods of Making Same and Products Containing Same; Notice...

    Science.gov (United States)

    2012-08-23

    ... INTERNATIONAL TRADE COMMISSION [Docket No. 2908] Certain Sintered Rare Earth Magnets, Methods of... Certain Sintered Rare Earth Magnets, Methods of Making Same and Products Containing Same, DN 2908; the..., methods of making same and products [[Page 51047

  3. GENESIS OF INTERPLANETARY INTERMITTENT TURBULENCE: A CASE STUDY OF ROPE–ROPE MAGNETIC RECONNECTION

    Energy Technology Data Exchange (ETDEWEB)

    Chian, Abraham C.-L.; Loew, Murray H. [Department of Biomedical Engineering, George Washington University, Washington, DC 20052 (United States); Feng, Heng Q. [Institute of Space Physics, Luoyang Normal University, Luoyang (China); Hu, Qiang [Department of Space Science and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Miranda, Rodrigo A. [UnB-Gama Campus, and Plasma Physics Laboratory, Institute of Physics, University of Brasília (UnB), Brasília DF 70910-900 (Brazil); Muñoz, Pablo R. [Department of Physics and Astronomy, University of La Serena, Av. Juan Cisternas 1200, La Serena (Chile); Sibeck, David G. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Wu, De J., E-mail: abraham.chian@gmail.com [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2016-12-01

    In a recent paper, the relation between current sheet, magnetic reconnection, and turbulence at the leading edge of an interplanetary coronal mass ejection was studied. We report here the observation of magnetic reconnection at the interface region of two interplanetary magnetic flux ropes. The front and rear boundary layers of three interplanetary magnetic flux ropes are identified, and the structures of magnetic flux ropes are reconstructed by the Grad–Shafranov method. A quantitative analysis of the reconnection condition and the degree of intermittency reveals that rope–rope magnetic reconnection is the most likely site for genesis of interplanetary intermittency turbulence in this event. The dynamic pressure pulse resulting from this reconnection triggers the onset of a geomagnetic storm.

  4. Effectiveness of using a magnetic spectrograph with the Trojan Horse method

    Science.gov (United States)

    Manwell, S.; Parikh, A.; Chen, A. A.; de Séréville, N.; Adsley, P.; Irvine, D.; Hammache, F.; Stefan, I.; Longland, R. F.; Tomlinson, J.; Morfuace, P.; Le Crom, B.

    2018-01-01

    The Trojan Horse method relies on performing reactions in a specific kinematic phase space that maximizes contributions of a quasi-free reaction mechanism. The hallmark of this method is that the incident particle can be accelerated to high enough energies to overcome the Coulomb barrier of the target, but once inside the target nucleus the relative motion of the clustered nuclei allows the reaction of interest to proceed at energies below this Coulomb Barrier. This method allows the experimentalist to probe reactions that have significance in astrophysics at low reaction energies that would otherwise be impossible due to the vanishing cross section. Traditionally the Trojan Horse method has been applied with the use of silicon detectors to observe the reaction products. In this study we apply the Trojan Horse method to a well studied reaction to examine the potential benefits of using a splitpole magnetic spectrograph to detect one of the reaction products. We have measure the three body 7Li(d,αn)α reaction to constrain the energy 7Li(d,α)α cross section. Measurements were first made using two silicon detectors, and then by replacing one detector with the magnetic spectrograph. The experimental design, limitations, and early results are discussed.

  5. Analysis of magnetic gradients to study gravitropism.

    Science.gov (United States)

    Hasenstein, Karl H; John, Susan; Scherp, Peter; Povinelli, Daniel; Mopper, Susan

    2013-01-01

    Gravitropism typically is generated by dense particles that respond to gravity. Experimental stimulation by high-gradient magnetic fields provides a new approach to selectively manipulate the gravisensing system. The movement of corn, wheat, and potato starch grains in suspension was examined with videomicroscopy during parabolic flights that generated 20 to 25 s of weightlessness. During weightlessness, a magnetic gradient was generated by inserting a wedge into a uniform, external magnetic field that caused repulsion of starch grains. The resultant velocity of movement was compared with the velocity of sedimentation under 1 g conditions. The high-gradient magnetic fields repelled the starch grains and generated a force of at least 0.6 g. Different wedge shapes significantly affected starch velocity and directionality of movement. Magnetic gradients are able to move diamagnetic compounds under weightless or microgravity conditions and serve as directional stimulus during seed germination in low-gravity environments. Further work can determine whether gravity sensing is based on force or contact between amyloplasts and statocyte membrane system.

  6. A method to solve the aircraft magnetic field model basing on geomagnetic environment simulation

    International Nuclear Information System (INIS)

    Lin, Chunsheng; Zhou, Jian-jun; Yang, Zhen-yu

    2015-01-01

    In aeromagnetic survey, it is difficult to solve the aircraft magnetic field model by flying for some unman controlled or disposable aircrafts. So a model solving method on the ground is proposed. The method simulates the geomagnetic environment where the aircraft is flying and creates the background magnetic field samples which is the same as the magnetic field arose by aircraft’s maneuvering. Then the aircraft magnetic field model can be solved by collecting the magnetic field samples. The method to simulate the magnetic environment and the method to control the errors are presented as well. Finally, an experiment is done for verification. The result shows that the model solving precision and stability by the method is well. The calculated model parameters by the method in one district can be used in worldwide districts as well. - Highlights: • A method to solve the aircraft magnetic field model on the ground is proposed. • The method solves the model by simulating dynamic geomagnetic environment as in the real flying. • The way to control the error of the method was analyzed. • An experiment is done for verification

  7. Deep-level defects in semiconductors: studies by magnetic resonance

    International Nuclear Information System (INIS)

    Ammerlaan, C.A.J.

    1983-01-01

    This work is divided into two parts. In the first one, the following topics are discussed: paramagnetic centers in semiconductors, principles of magnetic resonance, spin-Hamiltonian, g-tensor, hyperfine interaction, magnetic resonance spectrometer. In the second part it is dicussed defects studied by magnetic resonance including vacancy and divacancy in silicon, iron in silicon, nitrogen in diamond and antisite defects in III-V compounds. (A.C.A.S.) [pt

  8. Neutron diffraction studies of magnetic materials

    International Nuclear Information System (INIS)

    James, W.J.

    1987-01-01

    The ability of neutron diffraction in determining the nature and extent of magnetic ordering is illustrated for the intermetallic compounds, Y/sub 6/(Fe,Mn)/sub 23/ and ErFe/sub 3/. Substitution with other 3d transition metals influences the Fe-Fe exchange forces such as to alter, sometimes considerably, the magnetic properties, e.g., local site magnetic anisotropies in Er)Fe,Ni)/sub 3/ and thermal expansion anomalies in the R/sub 2/)Fe,Co)/sub 14/B compounds. When the 3d atoms are near neighbors in the periodic chart, their nuclear scattering lengths for neutrons are sufficiently different to permit the detection of preferential occupation of the several nonequivalent crystallographic 3d metal sites, i.e., atomic ordering, present in the R/sub 6/M/sub 23/, and R/sub 2/Fe/sub 14/B structures

  9. Design Study: ELENA Bending Magnet Prototype

    CERN Document Server

    Schoerling, D

    2013-01-01

    The ELENA bending magnet prototype shall prove that the proposed design meets the requirements set by the ELENA beam dynamics. The following points will be discussed in detail: (i) production process of a magnetic yoke diluted with stainless steel plates, (ii) the stability and repeatability of the field homogeneity of such a yoke over the full working range, (iii) choice of soft magnetic steel, (iv) hysteresis effects, (v) mechanical deformations, (vi) thermal insulation to intercept heat load from baking for activation of NEG coating in the vacuum chamber, (vii) end shim design. In order to verify these points the following measurements will be performed: (i) Hall probe scanning, (ii) integrated field homogeneity measurement (DC), (iii) integrated field homogeneity measurement (AC).

  10. Low temperature superconductor and aligned high temperature superconductor magnetic dipole system and method for producing high magnetic fields

    Science.gov (United States)

    Gupta, Ramesh; Scanlan, Ronald; Ghosh, Arup K.; Weggel, Robert J.; Palmer, Robert; Anerella, Michael D.; Schmalzle, Jesse

    2017-10-17

    A dipole-magnet system and method for producing high-magnetic-fields, including an open-region located in a radially-central-region to allow particle-beam transport and other uses, low-temperature-superconducting-coils comprised of low-temperature-superconducting-wire located in radially-outward-regions to generate high magnetic-fields, high-temperature-superconducting-coils comprised of high-temperature-superconducting-tape located in radially-inward-regions to generate even higher magnetic-fields and to reduce erroneous fields, support-structures to support the coils against large Lorentz-forces, a liquid-helium-system to cool the coils, and electrical-contacts to allow electric-current into and out of the coils. The high-temperature-superconducting-tape may be comprised of bismuth-strontium-calcium-copper-oxide or rare-earth-metal, barium-copper-oxide (ReBCO) where the rare-earth-metal may be yttrium, samarium, neodymium, or gadolinium. Advantageously, alignment of the large-dimension of the rectangular-cross-section or curved-cross-section of the high-temperature-superconducting-tape with the high-magnetic-field minimizes unwanted erroneous magnetic fields. Alignment may be accomplished by proper positioning, tilting the high-temperature-superconducting-coils, forming the high-temperature-superconducting-coils into a curved-cross-section, placing nonconducting wedge-shaped-material between windings, placing nonconducting curved-and-wedge-shaped-material between windings, or by a combination of these techniques.

  11. AC loss measurement of superconducting dipole magnets by the calorimetric method

    International Nuclear Information System (INIS)

    Morita, Y.; Hara, K.; Higashi, N.; Kabe, A.

    1996-01-01

    AC losses of superconducting dipole magnets were measured by the calorimetric method. The magnets were model dipole magnets designed for the SSC. These were fabricated at KEK with 50-mm aperture and 1.3-m overall length. The magnet was set in a helium cryostat and cooled down to 1.8 K with 130 L of pressurized superfluid helium. Heat dissipated by the magnet during ramp cycles was measured by temperature rise of the superfluid helium. Heat leakage into the helium cryostat was 1.6 W and was subtracted from the measured heat to obtain AC loss of the magnet. An electrical measurement was carried out for calibration. Results of the two methods agreed within the experimental accuracy. The authors present the helium cryostat and measurement system in detail, and discuss the results of AC loss measurement

  12. Magnetically responsive yeast cells: methods of preparation and applications

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Maděrová, Zdeňka; Pospišková, K.; Horská, Kateřina; Šafaříková, Miroslava

    2015-01-01

    Roč. 32, č. 1 (2015), s. 227-237 ISSN 0749-503X R&D Projects: GA MŠk(CZ) LD13023; GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : yeast cells * Saccharomyces * Kluyveromyces * Rhodotorula * Yarrowia * magnetic modification Subject RIV: CE - Biochemistry Impact factor: 2.259, year: 2015

  13. Nuclear magnetic resonance method and apparatus for reducing motion artifacts

    International Nuclear Information System (INIS)

    Bailes, D.R.

    1988-01-01

    A nuclear magnetic resonance apparatus for imaging a region of a body in which part of the region is moving with a motion such that its displacement with respect to time is a nonmonotonic function during a time period over which a plurality of NMR data signals, which together define an image, are collected. The apparatus is described comprising: excitation means arranged to excite nuclear magnetic spins preferentially in the region; encoding means arranged to encode the magnetic spins; data collection means arranged to collect data signals representative of encoded magnetic spins; display means responsive to collected data signals to display an image of the region; measuring means arranged to produce an output indicative of the displacement of the moving part of the region; and control means for controlling the encoding means during the time period in dependence on the output of the measuring means so that data signals collected during the time period are collected in an order dependent on the motion such that motion artifacts are reduced

  14. Basic artefacts of diagnostic imaging by the magnetic resonance method

    International Nuclear Information System (INIS)

    Vitak, T.; Seidl, Z.; Obenberger, J.; Vaneckova, M.; Danes, J.; Krasensky, J.; Peterkova, V

    2000-01-01

    Artefacts in diagnostic imaging are defined as a geometric or anatomic misrepresentation of the reality by the image formed. The article deals with artefacts due to field and frequency shifts, in particular due to the water-fat chemical shift and due to magnetic susceptibility. The physical nature of the artefacts is explained and their diagnostic significance is discussed. (P.A.)

  15. Application of Magnetic and Geotechnical Methods for Archaeological Site Investigations

    Science.gov (United States)

    2011-07-01

    national historic preservation act NRM natural remnant magnetism NS north-south nT nano Tesla ID inside diameter OSB oriented strand board psi...3.4 Soil Box Experiments Compaction tests were conducted by loading soil into a wooden box (1 m3) constructed of oriented strand board ( OSB ) and

  16. Study of the role of the ligands coordinated at the surface of pure Wuestite nanoparticles prepared following a room temperature organometallic method: Evidence of ferromagnetic - in shell- and antiferromagnetic - in core magnetic behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Glaria, Arnaud [CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse (France); Universite de Toulouse, UPS, INPT, LCC, F-31077 Toulouse (France); Kahn, Myrtil L., E-mail: myrtil.kahn@lcc-toulouse.fr [CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse (France); Universite de Toulouse, UPS, INPT, LCC, F-31077 Toulouse (France); Chaudret, Bruno [CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse (France); Universite de Toulouse, UPS, INPT, LCC, F-31077 Toulouse (France); Lecante, Pierre; Casanove, Marie-Jose [CNRS, CEMES (Centre d' Elaboration des Materiaux et d' Etudes Structurales), 29 rue Jeanne Marvig, BP 4347, 31055 Toulouse Cedex (France); Barbara, Bernard, E-mail: bernard.barbara@grenoble.cnrs.fr [Institut Louis Neel, CNRS, 25 Av. des martyrs, BP 166, 38042 Grenoble Cedex 09 (France)

    2011-09-15

    Highlights: {yields} Pure Wuestite (Fe{sub 1-y}O) nanoparticles synthesized by organometallic chemistry. {yields} The influence of the surface ligands on the magnetic properties. {yields} Ferromagnetic core-antiferromagnetic shell magnetic nanoparticles. - Abstract: Wuestite particles (Fe{sub 1-y}O) are synthesized using controlled hydrolysis at room temperature of [Fe(N(SiMe{sub 3}){sub 2}){sub 2}] and stabilized by amine ligands. This method leads to 5 nm pure wuestite particles. This phase is clearly identified by transmission electron microscopy and wide angle X-ray scattering. Distortion in the crystallographic structure has been demonstrated. Particular attention is paid on the Fe(III) formation. Moreover, a combination of Moessbauer spectroscopy and SQuID measurements, revealed that the particles are composed of an antiferromagnetic core surrounded by a ferromagnetic shell. According to the Neel theory, the Fe(III) and Fe(II) ions present in the particles are ferromagnetically coupled and the proportion of Fe(III) ions varies from 3.9 to 7.1% as a function of the amine ligand.

  17. Enhancement of magnetic properties of Co{sub 2}MnSi Heusler alloy prepared by mechanical alloying method

    Energy Technology Data Exchange (ETDEWEB)

    Rabie, Naeemeh; Gordani, Gholam Reza; Ghasemi, Ali, E-mail: ali13912001@yahoo.com

    2017-07-15

    Highlights: • Ferromagnetic Heusler alloys of Co{sub 2}MnSi were synthesized at low temperature. • There is an at least 30% reduction in the phase formation temperature. • Saturation magnetization of alloy was increased significantly after annealing. - Abstract: Ferromagnetic Heusler alloys of Co{sub 2}MnSi were synthesized by mechanical alloying method at low temperature. The effect of milling time and annealing process on structural and magnetic properties of ferromagnetic alloy samples were studied by X-ray diffraction, scanning electron microscopy and vibration sample magnetometer methods, respectively. Structural characteristics such as crystallite size, phase percentage, and lattice parameter determined using the Rietveld method. The values of these parameters were obtained 362.9 nm, 5.699 Å and 98.7%, respectively for annealed sample. Magnetization studies show that the Co2MnSi phase is formed at 15 h of milling and is optimized after 20 h of milling. VSM results showed that saturation magnetization (M{sub s}) of milled samples reduces from 112 to 75 (emu/g) with increasing milling time and then increased gradually to 95 emu/g. The effect of post-annealing on the structural and magnetic properties of milled samples was also investigated. The saturation magnetization of annealed sample (120 emu/g) is higher than the optimum milled sample (95 emu/g) due to increasing preferential ordered L2{sub 1} structure.

  18. Enhancement of magnetic properties of Co2MnSi Heusler alloy prepared by mechanical alloying method

    International Nuclear Information System (INIS)

    Rabie, Naeemeh; Gordani, Gholam Reza; Ghasemi, Ali

    2017-01-01

    Highlights: • Ferromagnetic Heusler alloys of Co 2 MnSi were synthesized at low temperature. • There is an at least 30% reduction in the phase formation temperature. • Saturation magnetization of alloy was increased significantly after annealing. - Abstract: Ferromagnetic Heusler alloys of Co 2 MnSi were synthesized by mechanical alloying method at low temperature. The effect of milling time and annealing process on structural and magnetic properties of ferromagnetic alloy samples were studied by X-ray diffraction, scanning electron microscopy and vibration sample magnetometer methods, respectively. Structural characteristics such as crystallite size, phase percentage, and lattice parameter determined using the Rietveld method. The values of these parameters were obtained 362.9 nm, 5.699 Å and 98.7%, respectively for annealed sample. Magnetization studies show that the Co2MnSi phase is formed at 15 h of milling and is optimized after 20 h of milling. VSM results showed that saturation magnetization (M s ) of milled samples reduces from 112 to 75 (emu/g) with increasing milling time and then increased gradually to 95 emu/g. The effect of post-annealing on the structural and magnetic properties of milled samples was also investigated. The saturation magnetization of annealed sample (120 emu/g) is higher than the optimum milled sample (95 emu/g) due to increasing preferential ordered L2 1 structure.

  19. Exchange coupling and magnetic anisotropy of exchanged-biased quantum tunnelling single-molecule magnet Ni3Mn2 complexes using theoretical methods based on Density Functional Theory.

    Science.gov (United States)

    Gómez-Coca, Silvia; Ruiz, Eliseo

    2012-03-07

    The magnetic properties of a new family of single-molecule magnet Ni(3)Mn(2) complexes were studied using theoretical methods based on Density Functional Theory (DFT). The first part of this study is devoted to analysing the exchange coupling constants, focusing on the intramolecular as well as the intermolecular interactions. The calculated intramolecular J values were in excellent agreement with the experimental data, which show that all the couplings are ferromagnetic, leading to an S = 7 ground state. The intermolecular interactions were investigated because the two complexes studied do not show tunnelling at zero magnetic field. Usually, this exchange-biased quantum tunnelling is attributed to the presence of intermolecular interactions calculated with the help of theoretical methods. The results indicate the presence of weak intermolecular antiferromagnetic couplings that cannot explain the ferromagnetic value found experimentally for one of the systems. In the second part, the goal is to analyse magnetic anisotropy through the calculation of the zero-field splitting parameters (D and E), using DFT methods including the spin-orbit effect.

  20. Apparatus and method for generating a magnetic field by rotation of a charge holding object

    Science.gov (United States)

    Gerald, II, Rex E.; Vukovic, Lela [Westchester, IL; Rathke, Jerome W [Homer Glenn, IL

    2009-10-13

    A device and a method for the production of a magnetic field using a Charge Holding Object that is mechanically rotated. In a preferred embodiment, a Charge Holding Object surrounding a sample rotates and subjects the sample to one or more magnetic fields. The one or more magnetic fields are used by NMR Electronics connected to an NMR Conductor positioned within the Charge Holding Object to perform NMR analysis of the sample.

  1. Studies on laws of stress-magnetization based on magnetic memory testing technique

    Science.gov (United States)

    Ren, Shangkun; Ren, Xianzhi

    2018-03-01

    Metal magnetic memory (MMM) testing technique is a novel testing method which can early test stress concentration status of ferromagnetic components. Under the different maximum tensile stress, the relationship between the leakage magnetic field of at certain point of cold rolled steel specimen and the tensile stress was measured during the process of loading and unloading by repeated. It shows that when the maximum tensile stress is less than 610 MPa, the relationship between the magnetic induction intensity and the stress is linear; When the maximum tensile stress increase from 610 MPa to 653 MPa of yield point, the relationship between the magnetic induction intensity and the tensile becomes bending line. The location of the extreme point of the bending line will move rapidly from the position of smaller stress to the larger stress position, and the variation of magnetic induction intensity increases rapidly. When the maximum tensile stress is greater than the 653 MPa of yield point, the variation of the magnetic induction intensity remains large, and the position of the extreme point moves very little. In theoretical aspects, tensile stress is to be divided into ordered stress and disordered stress. In the stage of elastic stress, a microscopic model of the order stress magnetization is established, and the conclusions are in good agreement with the experimental data. In the plastic deformation stage, a microscopic model of disordered stress magnetization is established, and the conclusions are in good agreement with the experimental data, too. The research results can provide reference for the accurate quantitative detection and evaluation of metal magnetic memory testing technology.

  2. Simulation of therapeutic electron beam tracking through a non-uniform magnetic field using finite element method.

    Science.gov (United States)

    Tahmasebibirgani, Mohammad Javad; Maskani, Reza; Behrooz, Mohammad Ali; Zabihzadeh, Mansour; Shahbazian, Hojatollah; Fatahiasl, Jafar; Chegeni, Nahid

    2017-04-01

    In radiotherapy, megaelectron volt (MeV) electrons are employed for treatment of superficial cancers. Magnetic fields can be used for deflection and deformation of the electron flow. A magnetic field is composed of non-uniform permanent magnets. The primary electrons are not mono-energetic and completely parallel. Calculation of electron beam deflection requires using complex mathematical methods. In this study, a device was made to apply a magnetic field to an electron beam and the path of electrons was simulated in the magnetic field using finite element method. A mini-applicator equipped with two neodymium permanent magnets was designed that enables tuning the distance between magnets. This device was placed in a standard applicator of Varian 2100 CD linear accelerator. The mini-applicator was simulated in CST Studio finite element software. Deflection angle and displacement of the electron beam was calculated after passing through the magnetic field. By determining a 2 to 5cm distance between two poles, various intensities of transverse magnetic field was created. The accelerator head was turned so that the deflected electrons became vertical to the water surface. To measure the displacement of the electron beam, EBT2 GafChromic films were employed. After being exposed, the films were scanned using HP G3010 reflection scanner and their optical density was extracted using programming in MATLAB environment. Displacement of the electron beam was compared with results of simulation after applying the magnetic field. Simulation results of the magnetic field showed good agreement with measured values. Maximum deflection angle for a 12 MeV beam was 32.9° and minimum deflection for 15 MeV was 12.1°. Measurement with the film showed precision of simulation in predicting the amount of displacement in the electron beam. A magnetic mini-applicator was made and simulated using finite element method. Deflection angle and displacement of electron beam were calculated. With

  3. Puzzle of magnetic moments of Ni clusters revisited using quantum Monte Carlo method.

    Science.gov (United States)

    Lee, Hung-Wen; Chang, Chun-Ming; Hsing, Cheng-Rong

    2017-02-28

    The puzzle of the magnetic moments of small nickel clusters arises from the discrepancy between values predicted using density functional theory (DFT) and experimental measurements. Traditional DFT approaches underestimate the magnetic moments of nickel clusters. Two fundamental problems are associated with this puzzle, namely, calculating the exchange-correlation interaction accurately and determining the global minimum structures of the clusters. Theoretically, the two problems can be solved using quantum Monte Carlo (QMC) calculations and the ab initio random structure searching (AIRSS) method correspondingly. Therefore, we combined the fixed-moment AIRSS and QMC methods to investigate the magnetic properties of Ni n (n = 5-9) clusters. The spin moments of the diffusion Monte Carlo (DMC) ground states are higher than those of the Perdew-Burke-Ernzerhof ground states and, in the case of Ni 8-9 , two new ground-state structures have been discovered using the DMC calculations. The predicted results are closer to the experimental findings, unlike the results predicted in previous standard DFT studies.

  4. Numerical investigations on applicability of permanent magnet method to crack detection in HTS film

    Energy Technology Data Exchange (ETDEWEB)

    Kamitani, A., E-mail: kamitani@yz.yamagata-u.ac.jp [Yamagata University, 4-3-16, Johnan, Yonezawa, Yamagata 992-8510 (Japan); Takayama, T. [Yamagata University, 4-3-16, Johnan, Yonezawa, Yamagata 992-8510 (Japan); Saitoh, A. [University of Hyogo, 2167, Shosha, Himeji, Hyogo 671-2280 (Japan)

    2014-09-15

    Highlights: • The defect parameter is defined for characterizing a crack position. • The defect parameter shows a remarkable change only near a crack. • A crack detection method is proposed on the basis of the permanent-magnet method. • The high-speed rough detection can be achieved by means of the proposed method. - Abstract: The scanning permanent-magnet (PM) method was originally developed for determining the spatial distribution of the critical current density in a high-temperature superconducting (HTS) film. In the present study, its applicability to the crack detection in an HTS film is investigated numerically. To this end, a defect parameter is defined for characterizing a crack position and it is calculated along various scanning lines. The results of computations show that, only when the scanning position is near a crack, the defect parameter shows a violent change. On the basis of the behavior of the defect parameter, the method for roughly identifying a crack is also proposed.

  5. Numerical investigations on applicability of permanent magnet method to crack detection in HTS film

    International Nuclear Information System (INIS)

    Kamitani, A.; Takayama, T.; Saitoh, A.

    2014-01-01

    Highlights: • The defect parameter is defined for characterizing a crack position. • The defect parameter shows a remarkable change only near a crack. • A crack detection method is proposed on the basis of the permanent-magnet method. • The high-speed rough detection can be achieved by means of the proposed method. - Abstract: The scanning permanent-magnet (PM) method was originally developed for determining the spatial distribution of the critical current density in a high-temperature superconducting (HTS) film. In the present study, its applicability to the crack detection in an HTS film is investigated numerically. To this end, a defect parameter is defined for characterizing a crack position and it is calculated along various scanning lines. The results of computations show that, only when the scanning position is near a crack, the defect parameter shows a violent change. On the basis of the behavior of the defect parameter, the method for roughly identifying a crack is also proposed

  6. Methods of high current magnetic field generator for transcranial magnetic stimulation application

    International Nuclear Information System (INIS)

    Bouda, N. R.; Pritchard, J.; Weber, R. J.; Mina, M.

    2015-01-01

    This paper describes the design procedures and underlying concepts of a novel High Current Magnetic Field Generator (HCMFG) with adjustable pulse width for transcranial magnetic stimulation applications. This is achieved by utilizing two different switching devices, the MOSFET and insulated gate bipolar transistor (IGBT). Results indicate that currents as high as ±1200 A can be generated with inputs of +/−20 V. Special attention to tradeoffs between field generators utilizing IGBT circuits (HCMFG 1 ) and MOSFET circuits (HCMFG 2 ) was considered. The theory of operation, design, experimental results, and electronic setup are presented and analyzed

  7. Methods of high current magnetic field generator for transcranial magnetic stimulation application

    Science.gov (United States)

    Bouda, N. R.; Pritchard, J.; Weber, R. J.; Mina, M.

    2015-05-01

    This paper describes the design procedures and underlying concepts of a novel High Current Magnetic Field Generator (HCMFG) with adjustable pulse width for transcranial magnetic stimulation applications. This is achieved by utilizing two different switching devices, the MOSFET and insulated gate bipolar transistor (IGBT). Results indicate that currents as high as ±1200 A can be generated with inputs of +/-20 V. Special attention to tradeoffs between field generators utilizing IGBT circuits (HCMFG1) and MOSFET circuits (HCMFG2) was considered. The theory of operation, design, experimental results, and electronic setup are presented and analyzed.

  8. Methods of high current magnetic field generator for transcranial magnetic stimulation application

    Energy Technology Data Exchange (ETDEWEB)

    Bouda, N. R., E-mail: nybouda@iastate.edu; Pritchard, J.; Weber, R. J.; Mina, M. [Department of Electrical and Computer engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2015-05-07

    This paper describes the design procedures and underlying concepts of a novel High Current Magnetic Field Generator (HCMFG) with adjustable pulse width for transcranial magnetic stimulation applications. This is achieved by utilizing two different switching devices, the MOSFET and insulated gate bipolar transistor (IGBT). Results indicate that currents as high as ±1200 A can be generated with inputs of +/−20 V. Special attention to tradeoffs between field generators utilizing IGBT circuits (HCMFG{sub 1}) and MOSFET circuits (HCMFG{sub 2}) was considered. The theory of operation, design, experimental results, and electronic setup are presented and analyzed.

  9. A simple method to prepare magnetic modified beer yeast and its application for cationic dye adsorption.

    Science.gov (United States)

    Yu, Jun-Xia; Wang, Li-Yan; Chi, Ru-An; Zhang, Yue-Fei; Xu, Zhi-Gao; Guo, Jia

    2013-01-01

    The purpose of this research is to use a simple method to prepare magnetic modified biomass with good adsorption performances for cationic ions. The magnetic modified biomass was prepared by two steps: (1) preparation of pyromellitic dianhydride (PMDA) modified biomass in N, N-dimethylacetamide solution and (2) preparation of magnetic PMDA modified biomass by a situ co-precipitation method under the assistance of ultrasound irradiation in ammonia water. The adsorption potential of the as-prepared magnetic modified biomass was analyzed by using cationic dyes: methylene blue and basic magenta as model dyes. Optical micrograph and x-ray diffraction analyses showed that Fe(3)O(4) particles were precipitated on the modified biomass surface. The as-prepared biosorbent could be recycled easily by using an applied magnetic field. Titration analysis showed that the total concentration of the functional groups on the magnetic PMDA modified biomass was calculated to be 0.75 mmol g(-1) by using the first derivative method. The adsorption capacities (q(m)) of the magnetic PMDA modified biomass for methylene blue and basic magenta were 609.0 and 520.9 mg g(-1), respectively, according to the Langmuir equation. Kinetics experiment showed that adsorption could be completed within 150 min for both dyes. The desorption experiment showed that the magnetic sorbent could be used repeatedly after regeneration. The as-prepared magnetic modified sorbent had a potential in the dyeing industry wastewater treatment.

  10. Neutron methods for the direct determination of the magnetic induction in thick films

    Energy Technology Data Exchange (ETDEWEB)

    Kozhevnikov, S.V., E-mail: kozhevn@nf.jinr.ru [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Ott, F. [CEA, IRAMIS, Laboratoire Léon Brillouin, F-91191 Gif sur Yvette (France); CNRS, IRAMIS, Laboratoire Léon Brillouin, F-91191 Gif sur Yvette (France); Radu, F. [Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Strasse 15, D-12489 Berlin (Germany)

    2016-03-15

    We review different neutron methods which allow extracting directly the value of the magnetic induction in thick films: Larmor precession, Zeeman spatial beam-splitting and neutron spin resonance. Resulting parameters obtained by the neutron methods and standard magnetometry technique are presented and compared. The possibilities and specificities of the neutron methods are discussed. - Highlights: • We present neutron methods for investigations of the thick magnetic films. • It is the methods for the direct determination of the magnetic induction. • Magnetic induction in bulk, at single interface and in a single domain. • It is Larmor precession, Zeeman spatial beam-splitting and neutron spin resonance. • These methods are complementary to polarized neutron reflectometry.

  11. Magnetic studies of dusts in the urban environment

    International Nuclear Information System (INIS)

    Xie, S.

    2000-12-01

    Dusts are one of the major public health concerns in the urban environment. This study investigates the application of magnetic techniques in the studies of urban dust pollution. Measurements of magnetic properties, element concentrations, and the organic matter content were carried out on Liverpool (UK) street dust and/or Bootle (UK) deposited dust. Mixed dominant ferrimagnetic phases are found in Liverpool street dust although magnetite is probably a major one. The partial susceptibility technique is able to model the contributions of main magnetic components satisfactorily in Liverpool street dust. There are similar spatial distributions for some measurements, such as χLF and Pb, whilst there are different patterns for some measurements, such as χLF and the organic matter content. There are good linear correlations between the organic matter content and some magnetic mineral concentration-related parameters for < 1mm (bulk) samples. Among them, frequency dependent susceptibility (χFD) shows the highest correlation coefficient value. χFD percentage demonstrates a significant correlation with the organic matter content for size fraction and bulk samples. This suggests that re-entrainment of soil is probably a major source of the organic material present in street dust. The ratio χARM /SIRM shows a highly significant correlation with the organic matter content for <150μm fraction samples. The study demonstrates that the simple, rapid, and non-destructive magnetic measurements may be used as proxies for the organic matter content in street dust. Associations between magnetic properties and element concentrations are investigated by using correlation analysis and factor analysis, which may be a potential approach for source identification of magnetic material in the environment. The study suggests that ferrimagnetic minerals are the dominant magnetic component in Bootle dust samples. Both studied sites show similar magnetic properties, but they can be

  12. The measurement of magnetic properties of electrical sheet steel - survey on methods and situation of standards

    CERN Document Server

    Sievert, J

    2000-01-01

    A brief review of the different requirements for magnetic measurement techniques for material research, modelling of material properties and grading of the electrical sheet steel for trade purposes is presented. In relation to the main application of laminated electrical steel, this paper deals with AC measurement techniques. Two standard methods, Epstein frame and Single Sheet Tester (SST), producing different results, are used in parallel. This dilemma was analysed in detail. The study leads to a possible solution of the problem, i.e. the possibility of converting the results of one of the two methods into the results of the other in order to satisfy the users of the Epstein method and, at the same time, to improve the acceptance of the more economical SST method.

  13. Magnetic excitations studied with time-of-flight spectroscopy

    International Nuclear Information System (INIS)

    Rainford, B.

    1996-01-01

    An introduction to time-of-flight neutron spectroscopy is presented in the context of the study of magnetic materials. Examples are taken from the class of rare earth and actinide magnetic materials known as 'strongly correlated electron' systems. (author) 11 figs., 24 refs

  14. Magnetic excitations studied with time-of-flight spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rainford, B [Southampton Univ. (United Kingdom). Dept. of Physics

    1996-11-01

    An introduction to time-of-flight neutron spectroscopy is presented in the context of the study of magnetic materials. Examples are taken from the class of rare earth and actinide magnetic materials known as `strongly correlated electron` systems. (author) 11 figs., 24 refs.

  15. Magnetic constraints on early lunar evolution revisited: Limits on accuracy imposed by methods of paleointensity measurements

    Science.gov (United States)

    Banerjee, S. K.

    1984-01-01

    It is impossible to carry out conventional paleointensity experiments requiring repeated heating and cooling to 770 C without chemical, physical or microstructural changes on lunar samples. Non-thermal methods of paleointensity determination have been sought: the two anhysteretic remanent magnetization (ARM) methods, and the saturation isothermal remanent magnetization (IRMS) method. Experimental errors inherent in these alternative approaches have been investigated to estimate the accuracy limits on the calculated paleointensities. Results are indicated in this report.

  16. Experimental Study on Position Control System Using Encoderless Magnetic Motion

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Youn; Heo, Hoon [Korea Univ., Seoul (Korea, Republic of); Yun, Young Min; Shim, Ho Keun; Kwon, Young Mok [TPC Mechatronics, Daejeon (Korea, Republic of)

    2016-01-15

    A position control system composed of the PMLSM(Permanent Magnet Linear Synchronous Motor), unlike conventional linear permanent magnet synchronous motor is fixed to the permanent magnet moving coil rails (permanent magnet = stator, coil = mover), the coil is fixed, moving the permanent magnet, we propose a position control system (permanent magnet = mover, coil = stator) structure. Position is measured not using conventional encoder or resolver but by adopting vector control method using 2 hall sensors generating rectangular signal. This method estimate the velocity and position of mover by using the quadruple of two hall sensor signal instead of encoder signal. Vector control of PMLSM using 2 hall sensor generating rectangular wave is proved to control the system stable and efficiently through simulation. Also hardware experiment reveals that the position control performance is measured within the range of 30-50μ in the accuracy of 10-20μ, which is improved twice to the conventional method. The proposed method exhibits its economical efficiency and practical usefulness. The vector control technique using two hall sensors can be installed in narrow place, accordingly it can be implemented on the system where the conventional encoder or resolver cannot operate.

  17. Review: Magnetic Resonance Spectroscopy Studies of Pediatric Major Depressive Disorder

    Directory of Open Access Journals (Sweden)

    Douglas G. Kondo

    2011-01-01

    Full Text Available Introduction. This paper focuses on the application of Magnetic Resonance Spectroscopy (MRS to the study of Major Depressive Disorder (MDD in children and adolescents. Method. A literature search using the National Institutes of Health's PubMed database was conducted to identify indexed peer-reviewed MRS studies in pediatric patients with MDD. Results. The literature search yielded 18 articles reporting original MRS data in pediatric MDD. Neurochemical alterations in Choline, Glutamate, and N-Acetyl Aspartate are associated with pediatric MDD, suggesting pathophysiologic continuity with adult MDD. Conclusions. The MRS literature in pediatric MDD is modest but growing. In studies that are methodologically comparable, the results have been consistent. Because it offers a noninvasive and repeatable measurement of relevant in vivo brain chemistry, MRS has the potential to provide insights into the pathophysiology of MDD as well as the mediators and moderators of treatment response.

  18. Statistical Study of the Magnetic Field Orientation in Solar Filaments

    Science.gov (United States)

    Hanaoka, Yoichiro; Sakurai, Takashi

    2017-12-01

    We have carried out a statistical study of the average orientation of the magnetic field in solar filaments with respect to their axes for more than 400 samples, based on data taken with daily full-Sun, full-Stokes spectropolarimetric observations using the He I 1083.0 nm line. The major part of the samples are the filaments in the quiet areas, but those in the active areas are included as well. The average orientation of the magnetic field in filaments shows a systematic property depending on the hemisphere; the direction of the magnetic field in filaments in the northern (southern) hemisphere mostly deviates clockwise (counterclockwise) from their axes, which run along the magnetic polarity inversion line. The deviation angles of the magnetic field from the axes are concentrated between 10° and 30°. This hemispheric pattern is consistent with that revealed for chirality of filament barbs, filament channels, and for other solar features found to possess chirality. For some filaments, it was confirmed that their magnetic field direction is locally parallel to their structure seen in Hα images. Our results for the first time confirmed this hemispheric pattern with the direct observation of the magnetic field in filaments. Interestingly, the filaments which show the opposite magnetic field deviation to the hemispheric pattern, are in many cases found above the polarity inversion line whose ambient photospheric magnetic field has the polarity alignment being opposite to that of active regions following the Hale–Nicholson law.

  19. Study of magnetization reversal processes in a thin Co film

    International Nuclear Information System (INIS)

    Chowdhury, N.; Bedanta, S.; Babu, G.S.

    2013-01-01

    The magnetization reversal has been studied both along the easy- and hard- axes for an in plane magnetized thin Cobalt film using magneto-optical Kerr effect (MOKE) microscope. We observe that magnetization reversal is governed by domain wall motion accompanied by nucleation when measured along the easy axis. However coherent rotation is observed during magnetization reversal when measured along the hard axis. The relaxation of magnetization in constant dc magnetic field measured along the easy axis shows exponential behaviour which according to Fatuzzo–Labrune model indicates domain nucleated dominant process. Domain wall velocity plotted as a function of constant dc magnetic field shows creep and slide regime from which the depinning transition was extracted. - Highlights: ► Kerr microscopy was performed for different field orientation to the easy axis. ► Here we have measured domain wall velocity in constant dc fields. ► Creep, depinning and slide modes of domain wall motion have been observed. ► Magnetic relaxation data can be very well fitted to Fatuzzo–Labrune model. ► Magnetization reversal occurs via domain nucleation and wall motion

  20. Magnets

    International Nuclear Information System (INIS)

    Young, I.R.

    1984-01-01

    A magnet pole piece for an NMR imaging magnet is made of a plurality of magnetic wires with one end of each wire held in a non-magnetic spacer, the other ends of the wires being brought to a pinch, and connected to a magnetic core. The wires may be embedded in a synthetic resin and the magnetisation and uniformity thereof can be varied by adjusting the density of the wires at the spacer which forms the pole piece. (author)

  1. Method and apparatus from imaging target components in a biological sample using permanent magnets

    NARCIS (Netherlands)

    Tibbe, Arjan G.J.; Terstappen, Leonardus Wendelinus Mathias Marie

    2010-01-01

    The present invention is a method and means for positive selecting and imaging target entities. This includes a coated permanent magnetic device for magnetic manipulation in the system of the present invention. The system immunomagnetically concentrates the target entity, fluorescently labels,

  2. A new method of measurement of tension on a moving magnetic tape

    Science.gov (United States)

    Kurtinaytis, A. K.; Lauzhinskas, Y. S.

    1973-01-01

    The possibility of no-contact measurement of the tension on a moving magnetic tape, assuming the tape is uniform, is discussed. A scheme for calculation of the natural frequency of transverse vibrations of magnetic tape is shown. Mathematical models are developed to show the relationships of the parameters. The method is applicable to the analysis of accurate tape feed mechanisms design.

  3. Magnetic, catalytic, EPR and electrochemical studies on binuclear ...

    Indian Academy of Sciences (India)

    Magnetic, catalytic, EPR and electrochemical studies on binuclear copper(II) complexes ... to the oxidation of 3,5-di--butylcatechol to the corresponding quinone. ... EPR spectral studies in methanol solvent show welldefined four hyperfine ...

  4. Mn-doped ZnO nanocrystals synthesized by sonochemical method: Structural, photoluminescence, and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A.A., E-mail: aaelho@yahoo.com [Assiut University, Faculty of Science, Department of Physics, Assiut 71516 (Egypt); Osman, M.A. [Assiut University, Faculty of Science, Department of Physics, Assiut 71516 (Egypt); Ibrahim, E.M.M. [Sohag University, Faculty of Science, Department of Physics, Sohag 82524 (Egypt); Ali, Manar A.; Abd-Elrahim, A.G. [Assiut University, Faculty of Science, Department of Physics, Assiut 71516 (Egypt)

    2017-05-15

    Highlights: • Mn-doped ZnO nanostructures were synthesized by the sonochemical method. • Structural, morphological, optical, photoluminescence and magnetic properties were investigated. • Mn-doped ZnO nanostructures reveal a blue shift of the optical band gap. • Photoluminescence spectra of Mn-doped ZnO nanostructures show quenching in the emission intensity. • Mn-doped ZnO nanostructures exhibit ferromagnetic ordering at room temperature. - Abstract: This work reports the synthesis of Mn-doped ZnO nanostructures using ice-bath assisted sonochemical technique. The impact of Mn-doping on structural, morphological, optical, and magnetic properties of ZnO nanostructures is studied. The morphological study shows that the lower doped samples possess mixtures of nanosheets and nanorods while the increase in Mn content leads to improvement of an anisotropic growth in a preferable orientation to form well-defined edge rods at Mn content of 0.04. UV–vis absorption spectra show that the exciton peak in the UV region is blue shifted due to Mn incorporation into the ZnO lattice. Doping ZnO with Mn ions leads to a reduction in the PL intensity due to a creation of more non-radiative recombination centers. The magnetic measurements show that the Mn-doped ZnO nanostructures exhibit ferromagnetic ordering at room temperature, as well as variation of the Mn content can significantly affect the ferromagnetic behavior of the samples.

  5. Study on designing of hexapole magnet of ECR ion source

    CERN Document Server

    Sun Liang Ting; Zhao Hong, Wei

    2004-01-01

    Detailed research has been done on the aspects of the design of a Halbach structure permanent hexapole, such as the permanent material adoption, the structure design, the dimension selection, etc. A possible method has been proposed to solve the problem of demagnetization in some magnetic blocks. By optimizing the geometry structure, the magnetic field in the working aperture is made to be the maximum for a certain condition. Some useful codes like POISSON, PERMAG, and TOSCA are used to simulate the sextuple magnetic field. Some useful plots are also presented.

  6. Polarized Epithermal Neutron Studies of Magnetic Domains

    International Nuclear Information System (INIS)

    Alfimenkov, V.P.; Chernikov, A.N.; Lason, L.; Mareev, Yu. D.; Novitsky, V.V.; Pikelner, L.B.; Skoy, V.R.; Tsulaya, M.I.; Gould, C.R.; Haase, D.G.; Roberson, N.R.

    1997-01-01

    The average size and shape of magnetic domains in a material can be determined from the precession of polarized neutrons traversing the material. Epithermal neutrons (0.5eV< En<100eV), which process more slowly than thermals, effectively probe the internal structure of samples that are thick or have large domains or large internal fields. Such epithermal neutron measurements require a neutron polarizer and analyzer based on cryogenically polarized spin filters. We discuss the measurements at JINR, Dubna, of magnetic domains in a 2.0 cm. diam. crystal of holmium using 1.7 to 59eV neutrons polarized by a dynamically polarized proton target and analyzed with a statically polarized dysprosium target

  7. Polarized epithermal neutron studies of magnetic domains

    International Nuclear Information System (INIS)

    Alfimenkov, V.P.; Chernikov, A.N.; Lason, L.; Mareev, Y.D.; Novitsky, V.V.; Pikelner, L.B.; Skoy, V.R.; Tsulaya, M.I.; Gould, C.R.; Haase, D.G.; the Triangle Universities Nuclear Laboratory, Durham, North Carolina; Roberson, N.R.; the Triangle Universities Nuclear Laboratory, Durham, North Carolina

    1997-01-01

    The average size and shape of magnetic domains in a material can be determined from the precession of polarized neutrons traversing the material. Epithermal neutrons (0.5eV n <100eV), which precess more slowly than thermals, effectively probe the internal structure of samples that are thick or have large domains or large internal fields. Such epithermal neutron measurements require a neutron polarizer and analyzer based on cryogenically polarized spin filters. We discuss the measurement at JINR, Dubna, of magnetic domains in a 2.0 cm. diam. crystal of holmium using 1.7 to 59 eV neutrons polarized by a dynamically polarized proton target and analyzed with a statically polarized dysprosium target. copyright 1997 American Institute of Physics

  8. A pilot study of planar coil based magnetic stimulation using acute hippocampal slice in mice.

    Science.gov (United States)

    Park, H J; Kang, H K; Wang, M; Jo, J; Chung, E; Kim, S

    2017-07-01

    Micromagnetic stimulation using small-sized implantable coils has recently been studied. The main advantage of this method is that it can provide sustainable stimulation performance even if a fibrotic encapsulation layer is formed around the implanted coil by inflammation response, because indirectly induced currents are used to induce neural responses. In previous research, we optimized the geometrical and control parameters used in implantable magnetic stimulation. Based on those results, we fabricated the planar coil and studied the LTP effect in the hippocampal slice by two different magnetic stimulation protocols using the quadripulse stimulation (QPS) pattern. We found that direct magnetic stimulation (DMS) induced insignificant LTP effect and priming magnetic stimulation (PMS) occluded LTP effect after tetanic stimulation, when QPS patterned magnetic stimulation with 1 A current pulse was applied to the planar coil.

  9. Subsurface Structure Determination of Geotermal Area in Siogung-ogung Samosir District by Using Magnetic Method

    Science.gov (United States)

    Tampubolon, Togi; Hutahaean, Juniar; Siregar, Suryani N. J.

    2018-03-01

    Underwater research often uses geomagnets. It is one of the geophysical methods for measuring magnetic field variations. This research was done to identify how the subsurface rock structure is and determine kinds of rock based on its susceptibility value in Siogung-ogung geothermal area, Pangururan, Samosir District. The tool measurement of total magnetic field called Proton Precission Magnetometer, positioning using Global Position System, and north axis determination using geological compass. Data collection was done randomly with total 51 measuring points obtained. Data analysis started with International geomagnetics Reference Field correction to obtain the total magnetic field anomaly. Then, the data analysis of total magnetic anomaly was done by using surfer program 12. To get a magnetic anomaly cross section used Magdc For Windows program. Magnetic measurement results indicated that the variation of magnetic field strength in each point with the lowest magnetic intensity value of 41785.67 nano tesla. The highest magnetic intensity value is 43140, 33. From the results of qualitative interpretation, the magnetic anomaly value is at -200.92 to 1154.45 whereas the quantitative interpretive results of model show the existence of degradation and andesitic rocks, with the value of susceptibility

  10. A comparison between progressive extension method (PEM) and iterative method (IM) for magnetic field extrapolations in the solar atmosphere

    Science.gov (United States)

    Wu, S. T.; Sun, M. T.; Sakurai, Takashi

    1990-01-01

    This paper presents a comparison between two numerical methods for the extrapolation of nonlinear force-free magnetic fields, viz the Iterative Method (IM) and the Progressive Extension Method (PEM). The advantages and disadvantages of these two methods are summarized, and the accuracy and numerical instability are discussed. On the basis of this investigation, it is claimed that the two methods do resemble each other qualitatively.

  11. An alternative 3D inversion method for magnetic anomalies with depth resolution

    Directory of Open Access Journals (Sweden)

    M. Chiappini

    2006-06-01

    Full Text Available This paper presents a new method to invert magnetic anomaly data in a variety of non-complex contexts when a priori information about the sources is not available. The region containing magnetic sources is discretized into a set of homogeneously magnetized rectangular prisms, polarized along a common direction. The magnetization distribution is calculated by solving an underdetermined linear system, and is accomplished through the simultaneous minimization of the norm of the solution and the misfit between the observed and the calculated field. Our algorithm makes use of a dipolar approximation to compute the magnetic field of the rectangular blocks. We show how this approximation, in conjunction with other correction factors, presents numerous advantages in terms of computing speed and depth resolution, and does not affect significantly the success of the inversion. The algorithm is tested on both synthetic and real magnetic datasets.

  12. On characteristics of magnetization by alternating current yoke method with running four poles

    International Nuclear Information System (INIS)

    Maeda, N.; Miyoshi, S.; Toriumi, T.

    1988-01-01

    In magnetic particle examinations, defects are most easily detected when a magnetic field is applied in a direction normal to the longitudinal direction of defects. It is well known that application of magnetic field intersecting at not less than 45 degrees to defects is necessary for detection of defects. Therefore, it is a general practice to perform magnetic particle examination with magnetization from two perpendicular directions in order to assure detection of defects whose direction is unknown. For example, in the case of the yoke method for welds, a common practice is to magnetize from two directions. The authors report how, to improve the ineffectiveness that testing must be performed twice, a new type of four-pole yoke was made

  13. Magnetic properties of carbon-coated, ferromagnetic nanoparticles produced by a carbon-arc method

    Science.gov (United States)

    Brunsman, E. M.; Sutton, R.; Bortz, E.; Kirkpatrick, S.; Midelfort, K.; Williams, J.; Smith, P.; McHenry, M. E.; Majetich, S. A.; Artman, J. O.; De Graef, M.; Staley, S. W.

    1994-05-01

    The Krätschmer-Huffman carbon-arc method of preparing fullerenes has been used to generate carbon-coated transition metal (TM) and TM-carbide nanocrystallites. The magnetic nanocrystallites were extracted from the soot with a magnetic gradient field technique. For TM=Co the majority of nanocrystals exist as nominally spherical particles, 0.5-5 nm in radius. Hysteretic and temperature-dependent magnetic response, in randomly and magnetically aligned powder samples frozen in epoxy, correspond to fine particle magnetism associated with monodomain TM particles. The magnetization exhibits a unique functional dependence on H/T, and hysteresis below a blocking temperature TB. Below TB, the temperature dependence of the coercivity can be expressed as Hc=Hc0[1-(T/TB)1/2], where Hc0 is the 0 K coercivity.

  14. Power flow studies of magnetically insulated lines

    International Nuclear Information System (INIS)

    McDaniel, D.H.; Poukey, J.W.; Bergeron, K.D.; VanDevender, J.P.; Johnson, D.L.

    1977-01-01

    The designs for relativistic electron beam accelerators with power levels of 20 to 100 TW are greatly restricted by the inductance of a single diode of reasonable size. This fact leads to modular designs of very large accelerators. One concept uses several small insulators at a large radius arranged around the accelerator center. The total effective inductance is then low, but the energy must then be transported by self-magnetic insulated vacuum lines to the target volume. A triplate vacuum line configuration eases many mechanical support problems and allows more A-K gaps or feeds to be packaged around a given radius. This type of vacuum transmission line was chosen for initial experiments at Sandia. The experiments were conducted on the MITE (Magnetically Insulated Transmission Experiment) accelerator. The water pulse forming lines are connected to a vacuum triplate line through a conventional stacked insulator. Diagnostics on the experiment consisted of: (1) input V; (2) input I; (3) I monitors at the input, middle, and output of both the center conductor and ground plane of the transmission line; (4) magnetic energy analyzer to view peak electron energy in the A-K gap; (5) calorimetry; and (6) Faraday cups to look at electron current flowing across the transmission line. The main goal of the experiment is to obtain input impedance of the transmission line as a function of voltage and to measure electron loss currents. These measurements are compared to theoretical models for the input impedance and energy losses

  15. Magnetic studies in evaporated Ni/Pd multilayers

    International Nuclear Information System (INIS)

    Chafai, K.; Salhi, H.; Lassri, H.; Yamkane, Z.; Lassri, M.; Abid, M.; Hlil, E.K.; Krishnan, R.

    2011-01-01

    The magnetic properties of Ni/Pd multilayers, prepared by sequential evaporation in ultrahigh vacuum, have been studied. The Ni thickness dependence of the magnetization and magnetic anisotropy is discussed. The temperature dependence of the spontaneous magnetization is well described by a T 3/2 law in all multilayers. A spin-wave theory has been used to explain the temperature dependence of the spontaneous magnetization, and the approximate values for the exchange interactions for various Ni layer thicknesses have been obtained. - Research highlights: → The magnetic properties of Ni/Pd multilayers, prepared by sequential evaporation in ultrahigh vacuum, have been studied. → The temperature dependence of the spontaneous magnetization is well described by a T 3/2 law in Ni/Pd multilayers. → The spin-wave constant B was observed to depend on t Ni nonmonotonically. → A spin-wave theory has been used to explain the temperature dependence of the spontaneous magnetization. → The approximate values for the exchange interactions for various Ni layer thicknesses have been obtained.

  16. Study of local correlations of magnetic and multiferroic compounds

    CERN Multimedia

    Alves, E J

    We propose to study magnetic and multiferroic strongly correlated electron materials using radioactive nuclear probe techniques, at ISOLDE . Following the strategy of a previous project, IS390, our aim is to provide local and element selective information on some of the mechanisms that rule structural, charge and orbital correlations, electronic and magnetic interactions and the coupling of the associated degrees of freedom. The main technique used is Perturbed Angular Correlations (PAC), which allows combined magnetic and electric hyperfine studies. This study is complemented by the use of conventional characterisation techniques, and the investigation of relevant macroscopic properties.

  17. Accuracy of signal-to-noise ratio measurement method for magnetic resonance images

    International Nuclear Information System (INIS)

    Ogura, Akio; Miyai, Akira; Maeda, Fumie; Fukutake, Hiroyuki; Kikumoto, Rikiya

    2003-01-01

    The signal-to-noise ratio (SNR) of a magnetic resonance image is a common measure of imager performance. However, evaluations for the calculation of the SNR use various methods. A problem with measuring SNR is caused by the distortion of noise statistics in commonly used magnitude images. In this study, measurement accuracy was compared among four methods of evaluating SNR according to the size and position of regions of interest (ROIs). The results indicated that the method that used the difference between two images showed the best agreement with the theoretical value. In the method that used a single image, the SNR calculated by using a small size of ROI showed better agreement with the theoretical value because of noise bias and image artifacts. However, in the method that used the difference between two images, a large size of ROI was better in reducing statistical errors. In the same way, the methods that used air noise and air signal were better when applied to a large ROI. In addition, the image subtraction process used to calculate pixel-by-pixel differences in images may reach zero on a minus pixel value when using an image processor with the MRI system and apparatuses associated with it. A revised equation is presented for this case. It is important to understand the characteristics of each method and to choose a suitable method carefully according to the purpose of the study. (author)

  18. Simplified analysis method for vibration of fusion reactor components with magnetic damping

    International Nuclear Information System (INIS)

    Tanaka, Yoshikazu; Horie, Tomoyoshi; Niho, Tomoya

    2000-01-01

    This paper describes two simplified analysis methods for the magnetically damped vibration. One is the method modifying the result of finite element uncoupled analysis using the coupling intensity parameter, and the other is the method using the solution and coupled eigenvalues of the single-degree-of-freedom coupled model. To verify these methods, numerical analyses of a plate and a thin cylinder are performed. The comparison between the results of the former method and the finite element tightly coupled analysis show almost satisfactory agreement. The results of the latter method agree very well with the finite element tightly coupled results because of the coupled eigenvalues. Since the vibration with magnetic damping can be evaluated using these methods without finite element coupled analysis, these approximate methods will be practical and useful for the wide range of design analyses taking account of the magnetic damping effect

  19. Methods of developing an emission cataster for low frequency electric and magnetic fields

    International Nuclear Information System (INIS)

    Stenzel, E.; Frohn, O.; Koffke, K.; Dunker, J.; Plotzke, O.

    1996-01-01

    In the common environment each individual is exposed to a large variety of power frequency or extremely low frequency (EFL) electric and magnetic fields. Traditionally these fields have been thought to be harmless but recent scientific studies reveal, however, that at least effects do exists. Therefore father investigations have to be carried out in order to obtain a greater data base. As a major point new ways have to be established that allow an effective collection of an relevant data concerning the exposition m this fields. In our contribution for the first time methods that consider simultaneously an major field emittants in the ramp of 0-500 Hz spread over the area as great as a town district. These methods have been developed and successfully tested in the district Buch/Karow of Berlin during the research study 'emission cataster of electric and magnetic field exposure in Berlin -a comparative study in selected public areas'. In this study the following field sources have been taken to consideration: i) 110-kV, 220-kV, 380-kV transmission lines, ii) 110-kV power transmission cables, iii) relay station Karow, iv) 10-kV medium voltage level, v) 1-kV distribution level, vi) power stations, vii) railway, viii) urban railway. (author)

  20. Micro-scale grain-size analysis and magnetic properties of coal-fired power plant fly ash and its relevance for environmental magnetic pollution studies

    Energy Technology Data Exchange (ETDEWEB)

    Blaha, U.; Sapkota, B.; Appel, E.; Stanjek, H.; Rosler, W. [University of Tubingen, Tubingen (Germany). Inst. of Geoscience

    2008-11-15

    Two fly ash samples from a black coal-fired power plant (Bexbach, Germany) were investigated for their magnetic properties, particle structure, grain-size distribution and chemical composition. Grain-size distribution was determined on bulk samples and on magnetic extracts. Magnetic susceptibility of different grain-size fractions was analyzed with respect to the according amount of fractions, high- and low-temperature dependence of magnetic susceptibility and thermal demagnetization of IRM identified magnetite and hematite as magnetic phases. Magnetic spherules were quantitatively extracted from bulk fly ash samples and examined using SEM/EDX analysis. Particle morphology and grain-size analysis on the magnetically extracted material were studied. Individual spherule types were identified and internal structures of selected polished particles were investigated by SEM and EDX analyses. Main element contents of the internal structures which consist of 'magnetite' crystals and 'glassy' matrix were systematically determined and statistically assessed. The chemical data of the micro-scale structures in the magnetic spherules were compared with XRF data from bulk material, revealing the relative element distribution in composed magnetic spherules. Comparison of the bulk sample grain-size (0.5-300 {mu}m) and grain-size spectra from magnetic extracts (1-186.5 {mu}m) shows that strongly magnetic particles mainly occur in the fine fractions of < 63 {mu}m. This study comprises a comprehensive characterization of coal-fired power plant fly ash, using magnetic, chemical, and microscopic methods. The results can serve as reference data for a variety of environmental magnetic studies.