Sample records for imaging current-driven magnetic

  1. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for technological development, repetitive pulse experiments also showed that many of the pulses gave smaller speeds or no movement at all, so that the current-driven motion...

  2. Experimental Study of Current-Driven Turbulence During Magnetic Reconnection

    SciTech Connect (OSTI)

    Miklos Porkolab; Jan Egedal-Pedersen; William Fox

    2010-08-31T23:59:59.000Z

    CMPD Final Report Experimental Study of Current-Driven Turbulence During Magnetic Reconnection Miklos Porkolab, PI, Jan Egedal, co-PI, William Fox, graduate student. This is the final report for Grant DE-FC02-04ER54786, �¢����MIT Participation in the Center for Multiscale Plasma Dynamics,�¢��� which was active from 8/1/2004 to 7/31/2010. This Grant supported the thesis work of one MIT graduate student, William Fox, The thesis research consisted of an experimental study of the fluctuations arising during magnetic reconnection in plasmas on the Versatile Toroidal Facility (VTF) at MIT Plasma Science and Fusion Center (PSFC). The thesis was submitted and accepted by the MIT physics Department, �¢����W. Fox, Experimental Study of Current-Driven Turbulence During Magnetic Reconnection, Ph.D. Thesis, MIT (2009)�¢���. In the VTF experiment reconnection and current-sheet formation is driven by quickly changing currents in a specially arranged set of internal conductors. Previous work on this device [Egedal, et al, PRL 98, 015003, (2007)] identified a �¢����spontaneous�¢��� reconnection regime. In this work fluctuations were studied using impedance-matched, high-bandwidth Langmuir probes. Strong, broadband fluctuations, with frequencies extending from near the lower-hybrid frequency [fLH = (fcefci)1/2] to the electron cyclotron frequency fce were found to arise during the reconnection events. Based on frequency and wavelength measurements, lower-hybrid waves and Trivelpiece-Gould waves were identified. The lower-hybrid waves are easiest to drive with strong perpendicular drifts or gradients which arise due to the reconnection events; an appealing possibility is strong temperature gradients. The Trivelpiece-Gould modes can result from kinetic, bump-on-tail instability of a runaway electron population energized by the reconnection events. We also observed that the turbulence is often spiky, consisting of discrete positive-potential spikes, which were identified as �¢����electron phase-space holes,�¢��� a class of nonlinear solitary wave known to evolve from a strong beam-on-tail instability. We established that fast electrons were produced by magnetic reconnection. Overall, these instabilities were found to be a consequence of reconnection, specifically the strong energization of electrons, leading to steep gradients in both coordinate- and velocity-space. Estimates (using quasi-linear theory) of the anomalous resistivity due to these modes did not appear large enough to substantially impact the reconnection process. Relevant publications: �¢���¢ W. Fox, M. Porkolab, et al, Phys. Rev. Lett. 101, 255003 (2008). �¢���¢ W. Fox, M. Porkolab, et al, Phys. Plasmas 17, 072303, (2010).

  3. Experimental study of current-driven turbulence during magnetic reconnection

    E-Print Network [OSTI]

    Fox, William Randolph, II

    2009-01-01T23:59:59.000Z

    Magnetic reconnection is an important process in magnetized plasmas ranging from the laboratory to astrophysical scales. It enables the release of magnetic energy believed to power solar flares and magnetospheric substorms. ...

  4. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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  5. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

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  6. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  7. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  8. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  9. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  10. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  11. X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  12. Magnetic Imaging Wolfgang Kuch

    E-Print Network [OSTI]

    Kuch, Wolfgang

    Magnetic Imaging Wolfgang Kuch Freie Universit¨at Berlin, Institut f¨ur Experimentalphysik, Arnimallee 14, 14195 Berlin, Germany kuch@physik.fu-berlin.de Abstract. Imaging of magnetic domains has- ern techniques is used nowadays routinely for magnetic imaging of magnetic ma- terials

  13. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    this technique has been especially popular in imaging such complex structures as aerogels and yeast cells. When applying the CDI technique to a magnetic system, the same...

  14. Enlarge Image Peer pressure. Magnetic

    E-Print Network [OSTI]

    Thywissen, Joseph

    to stick it to your refrigerator, but an ultra-cold gas magnetizes itself just as do metals such as ironEnlarge Image Peer pressure. Magnetic domains in steel (vertical bans) arise when neighboring electrons point their magnetic poles in the same direction. CREDIT: ZUREKS, CHRIS VARDON

  15. Low field magnetic resonance imaging

    DOE Patents [OSTI]

    Pines, Alexander (Berkeley, CA); Sakellariou, Dimitrios (Billancourt, FR); Meriles, Carlos A. (Fort Lee, NJ); Trabesinger, Andreas H. (London, GB)

    2010-07-13T23:59:59.000Z

    A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

  16. Enlarge Image Peer pressure. Magnetic

    E-Print Network [OSTI]

    Enlarge Image Peer pressure. Magnetic domains in steel (vertical bans) arise when neighboring electrons point their magnetic poles in the same direction. CREDIT: ZUREKS, CHRIS VARDON/WIKIMEDIA By Adrian Cho ScienceNOW Daily News 18 September 2009 It would be tough to stick it to your refrigerator

  17. Current-Driven Filament Instabilities in Relativistic Plasmas. Final report

    SciTech Connect (OSTI)

    Chuang Ren

    2013-02-13T23:59:59.000Z

    This grant has supported a study of some fundamental problems in current- and flow-driven instabilities in plasmas and their applications in inertial confinement fusion (ICF) and astrophysics. It addressed current-driven instabilities and their roles in fast ignition, and flow-driven instabilities and their applications in astrophysics.

  18. Chapter 20. Magnetic Resonance Imaging Magnetic Resonance Imaging

    E-Print Network [OSTI]

    , and software training from Siemens Medical Solutions; research funding through the Siemens-MIT Alliance and Technology (HST). 2 Siemens Medical Solutions, Erlangen, Germany. #12;Chapter 20. Magnetic Resonance Imaging, Siemens Medical Solutions, Siemens-MIT Alliance, HST Martinos Catalyst Fund. Project Staff: Audrey P. Fan

  19. A Molecular Switch Based on Current-Driven Rotation of an Encapsulated...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Switch Based on Current-Driven Rotation of an Encapsulated Cluster within a Fullerene Cage. A Molecular Switch Based on Current-Driven Rotation of an Encapsulated Cluster within a...

  20. Instrumentation for parallel magnetic resonance imaging

    E-Print Network [OSTI]

    Brown, David Gerald

    2007-04-25T23:59:59.000Z

    Parallel magnetic resonance (MR) imaging may be used to increase either the throughput or the speed of the MR imaging experiment. As such, parallel imaging may be accomplished either through a "parallelization" of the MR experiment, or by the use...

  1. Magnetic Resonance Imaging System Based on Earth's Magnetic Field

    E-Print Network [OSTI]

    Stepi?nik, Janez

    Magnetic Resonance Imaging System Based on Earth's Magnetic Field Ales Mohoric,1,* Gorazd Planinsic magnetic field can be partly compensated by the receiving coil design and shielding of electromagnetic pick and must be monitored accurately.[8­ 10] The importance of NMR in a non-uniform magnetic field

  2. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 -ofLearningLensless Imaging of Magnetic

  3. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 -ofLearningLensless Imaging of MagneticLensless

  4. Imaging agents for in vivo magnetic resonance and scintigraphic imaging

    DOE Patents [OSTI]

    Engelstad, B.L.; Raymond, K.N.; Huberty, J.P.; White, D.L.

    1991-04-23T23:59:59.000Z

    Methods are provided for in vivo magnetic resonance imaging and/or scintigraphic imaging of a subject using chelated transition metal and lanthanide metal complexes. Novel ligands for these complexes are provided. No Drawings

  5. BOOTSTRAP-CURRENT-DRIVEN STEADY-STATE TOKAMAK J.C. Sprott

    E-Print Network [OSTI]

    Sprott, Julien Clinton

    BOOTSTRAP-CURRENT-DRIVEN STEADY-STATE TOKAMAK J.C. Sprott PLP 891 January 1983 Plasma Studies of the authors and major professor. #12;BOOTSTRAP-CURRENT-DRIVEN STEADY-STATE TOKAMAK J.C. Sprott We examime here the possibility of modifying the Levitated Octupole to operate as a tokamak with a rotational transform produced

  6. Single echo acquisition magnetic resonance imaging 

    E-Print Network [OSTI]

    McDougall, Mary Preston

    2006-04-12T23:59:59.000Z

    The dramatic improvement in magnetic resonance imaging (MRI) scan time over the past fifteen years through gradient-based methods that sample k-space more efficiently and quickly cannot be sustained, as thresholds regarding ...

  7. Magnetic field imaging with atomic Rb vapor

    E-Print Network [OSTI]

    Eugeniy E. Mikhailov; I. Novikova; M. D. Havey; F. A. Narducci

    2009-07-27T23:59:59.000Z

    We demonstrate the possibility of dynamic imaging of magnetic fields using electromagnetically induced transparency in an atomic gas. As an experimental demonstration we employ an atomic Rb gas confined in a glass cell to image the transverse magnetic field created by a long straight wire. In this arrangement, which clearly reveals the essential effect, the field of view is about 2 x 2 mm^2 and the field detection uncertainty is 0.14 mG per 10 um x 10 um image pixel.

  8. Filamentation instability of current-driven dust ion-acoustic waves in a collisional dusty plasma

    SciTech Connect (OSTI)

    Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 19839-63113 (Iran, Islamic Republic of); Haghtalab, T.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand 97179-63384 (Iran, Islamic Republic of)

    2011-11-15T23:59:59.000Z

    A theoretical investigation has been made of the dust ion-acoustic filamentation instability in an unmagnetized current-driven dusty plasma by using the Lorentz transformation formulas. The effect of collision between the charged particles with neutrals and their thermal motion on this instability is considered. Developing the filamentation instability of the current-driven dust ion-acoustic wave allows us to determine the period and the establishment time of the filamentation structure and threshold for instability development.

  9. Magnetic particle imaging of blood coagulation

    SciTech Connect (OSTI)

    Murase, Kenya, E-mail: murase@sahs.med.osaka-u.ac.jp; Song, Ruixiao; Hiratsuka, Samu [Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine, Osaka University, Osaka 565-0871 (Japan)

    2014-06-23T23:59:59.000Z

    We investigated the feasibility of visualizing blood coagulation using a system for magnetic particle imaging (MPI). A magnetic field-free line is generated using two opposing neodymium magnets and transverse images are reconstructed from the third-harmonic signals received by a gradiometer coil, using the maximum likelihood-expectation maximization algorithm. Our MPI system was used to image the blood coagulation induced by adding CaCl{sub 2} to whole sheep blood mixed with magnetic nanoparticles (MNPs). The “MPI value” was defined as the pixel value of the transverse image reconstructed from the third-harmonic signals. MPI values were significantly smaller for coagulated blood samples than those without coagulation. We confirmed the rationale of these results by calculating the third-harmonic signals for the measured viscosities of samples, with an assumption that the magnetization and particle size distribution of MNPs obey the Langevin equation and log-normal distribution, respectively. We concluded that MPI can be useful for visualizing blood coagulation.

  10. Magnetic Resonance Imaging (MRI) of PEM Dehydration and Gas Manifold...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Resonance Imaging (MRI) of PEM Dehydration and Gas Manifold Flooding During Continuous Fuel Cell Operation. Magnetic Resonance Imaging (MRI) of PEM Dehydration and Gas Manifold...

  11. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your HomeLatest News ReleasesDepartmentLending a HandImaging of

  12. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your HomeLatest News ReleasesDepartmentLending a HandImaging

  13. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 -ofLearningLensless Imaging of

  14. Model-based reconstruction of magnetic resonance spectroscopic imaging

    E-Print Network [OSTI]

    Chatnuntawech, Itthi

    2013-01-01T23:59:59.000Z

    Magnetic resonance imaging (MRI) is a medical imaging technique that is used to obtain images of soft tissue throughout the body. Since its development in the 1970s, MRI has gained tremendous importance in clinical practice ...

  15. Magnetic resonance imaging of self-assembled biomaterial scaffolds

    SciTech Connect (OSTI)

    Bull, Steve R; Meade, Thomas J; Stupp, Samuel I

    2014-09-16T23:59:59.000Z

    Compositions and/or mixtures comprising peptide amphiphile compounds comprising one or more contrast agents, as can be used in a range of magnetic resonance imaging applications.

  16. Designing and characterizing hyperpolarizable silicon nanoparticles for magnetic resonance imaging

    E-Print Network [OSTI]

    Anahtar, Melis Nuray

    2008-01-01T23:59:59.000Z

    Magnetic Resonance Imaging (MRI) is one of the most powerful noninvasive tools for diagnosing human disease, but its utility is limited because current contrast agents are ineffective when imaging air-tissue interfaces, ...

  17. Magnetic resonance spectroscopic imaging using parallel transmission at 7T

    E-Print Network [OSTI]

    Gagoski, Borjan Aleksandar

    2011-01-01T23:59:59.000Z

    Conventional magnetic resonance spectroscopic imaging (MRSI), also known as phase-encoded (PE) chemical shift imaging (CSI), suffers from both low signal-to-noise ratio (SNR) of the brain metabolites, as well as inflexible ...

  18. Magnetic Microscopy and Imaging II John Chapman, Chairman Study of in-plane magnetic domains with magnetic transmission

    E-Print Network [OSTI]

    Bayreuther, Günther

    with magnetic transmission x-ray microscopy P. Fischer,a) T. Eimu¨ller, and G. Schu¨tz University of Wu be designed by en- gaging, e.g., the different magnetic couplings between each layers. Due to a balanceMagnetic Microscopy and Imaging II John Chapman, Chairman Study of in-plane magnetic domains

  19. Dust-acoustic filamentation of a current-driven dusty plasma

    SciTech Connect (OSTI)

    Khorashadizadeh, S. M.; Haghtalab, T. [Physics Department, Birjand University, Birjand, 97179-63384 (Iran, Islamic Republic of); Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran, 19839-63113 (Iran, Islamic Republic of)

    2011-06-15T23:59:59.000Z

    The thermal motion effect of charged particles in the filamentation of a current-driven dusty plasma in the dust-acoustic frequency region is investigated by using the Lorentz transformed conductivity of the dusty plasma components and the total dielectric permittivity tensor of the dusty plasma in the laboratory frame. Obtaining the dispersion relation for dust-acoustic waves and considering the filamentation instability, the establishment time of the filamentation structure and the instability development threshold are derived. Moreover, it is shown that the current layer divides into separate current filaments.

  20. Improvements in magnetic resonance imaging excitation pulse design

    E-Print Network [OSTI]

    Zelinski, Adam Charles

    2008-01-01T23:59:59.000Z

    This thesis focuses on the design of magnetic resonance imaging (MRI) radio-frequency (RF) excitation pulses, and its primary contributions are made through connections with the novel multiple-system single-output (MSSO) ...

  1. Design algorithms for parallel transmission in magnetic resonance imaging

    E-Print Network [OSTI]

    Setsompop, Kawin

    2008-01-01T23:59:59.000Z

    The focus of this dissertation is on the algorithm design, implementation, and validation of parallel transmission technology in Magnetic Resonance Imaging (MRI). Novel algorithms are proposed which yield excellent excitation ...

  2. RF Pulse Design for Parallel Excitation in Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Liu, Yinan

    2012-07-16T23:59:59.000Z

    Parallel excitation is an emerging technique to improve or accelerate multi-dimensional spatially selective excitations in magnetic resonance imaging (MRI) using multi-channel transmit arrays. The technique has potential in many applications...

  3. Surface-Based Analysis of Functional Magnetic Resonance Imaging Data

    E-Print Network [OSTI]

    Thompson, Paul

    Surface-Based Analysis of Functional Magnetic Resonance Imaging Data Theo G.M. van Erp1, Vikas Y School of Medicine, Los Angeles, CA 90095, USA Abstract. Surface-based visualization, atlases the integration of surface-based tech- niques with functional imaging data, combining surface-based nonlinear

  4. Direct Imaging of Asymmetric Magnetization Reversal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    new information storage and sensing devices. There are two basic energies involved in the manipulation and control of the magnetic properties of materials. Exchange controls...

  5. He Lung Imaging in an Open Access, Very-Low-Field Human Magnetic Resonance Imaging System

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    3 He Lung Imaging in an Open Access, Very-Low-Field Human Magnetic Resonance Imaging System R. W. Butler,6 F. W. Hersman,4 and R. L. Walsworth1 The human lung and its functions are extremely sensitive lung restrict sub- jects to lying horizontally. Imaging of human lungs using inhaled laser-polarized 3

  6. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in...

  7. Method for nuclear magnetic resonance imaging

    DOE Patents [OSTI]

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

    1988-05-26T23:59:59.000Z

    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.

  8. Application of Parallel Imaging to Murine Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Chang, Chieh-Wei 1980-

    2012-09-21T23:59:59.000Z

    . This dissertation describes foundational level work to enable parallel imaging of mice on a 4.7 Tesla/40 cm bore research scanner. Reducing the size of the hardware setup associated with typical parallel imaging was an integral part of achieving the work, as animal...

  9. Directed evolution of a magnetic resonance imaging contrast agent for noninvasive imaging of dopamine

    E-Print Network [OSTI]

    Shapiro, Mikhail G.

    The development of molecular probes that allow in vivo imaging of neural signaling processes with high temporal and spatial resolution remains challenging. Here we applied directed evolution techniques to create magnetic ...

  10. Parallel magnetic resonance imaging: characterization and comparison

    E-Print Network [OSTI]

    Rane, Swati Dnyandeo

    2005-11-01T23:59:59.000Z

    [Sodickson, 1997], GRAPPA [Griswold, 2002] and SPACE RIP [Kyriakos, 2000]; developed in the past decade have been studied, simulated and compared in this research. Because of the dependence of the parallel imaging methods on numerous factors such as receiver...

  11. Portable low-cost magnetic resonance imaging

    E-Print Network [OSTI]

    Cooley, Clarissa Zimmerman

    2014-01-01T23:59:59.000Z

    Purpose: As the premiere modality for brain imaging, MRI could find wider applicability if lightweight, portable systems were available for siting in unconventional locations such as intensive care units (ICUs), physician ...

  12. Original Research Magnetic Resonance Image-Guided Trans-Septal

    E-Print Network [OSTI]

    Atalar, Ergin

    vasculature. Key Words: interventional; magnetic resonance imaging; trans-septal catheterization; cardiac; MR with a pigtail catheter in the aorta and the use of His bundle/coronary sinus catheters (1), and, more recently from a percutaneous femoral vein ap- proach. MATERIALS AND METHODS Animal Model The Institutional

  13. Blood Flow Magnetic Resonance Imaging of Retinal Degeneration

    E-Print Network [OSTI]

    Duong, Timothy Q.

    Blood Flow Magnetic Resonance Imaging of Retinal Degeneration Yingxia Li,1 Haiying Cheng,1 Qiang. Duong1,2,3,4,5,6,7 PURPOSE. This study aims to investigate quantitative basal blood flow as well as hypercapnia- and hyperoxia-induced blood flow changes in the retinas of the Royal College of Surgeons (RCS

  14. Direct Imaging of Asymmetric Magnetization Reversal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign: PotentialFederal Financial InterventionsDirect Imaging of

  15. Direct Imaging of Asymmetric Magnetization Reversal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign: PotentialFederal Financial InterventionsDirect Imaging

  16. Direct Imaging of Asymmetric Magnetization Reversal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign: PotentialFederal Financial InterventionsDirect ImagingDirect

  17. Ultra-low field nuclear magnetic resonance and magnetic resonance imaging to discriminate and identify materials

    DOE Patents [OSTI]

    Kraus, Robert H. (Los Alamos, NM); Matlashov, Andrei N. (Los Alamos, NM); Espy, Michelle A. (Los Alamos, NM); Volegov, Petr L. (Los Alamos, NM)

    2010-03-30T23:59:59.000Z

    An ultra-low magnetic field NMR system can non-invasively examine containers. Database matching techniques can then identify hazardous materials within the containers. Ultra-low field NMR systems are ideal for this purpose because they do not require large powerful magnets and because they can examine materials enclosed in conductive shells such as lead shells. The NMR examination technique can be combined with ultra-low field NMR imaging, where an NMR image is obtained and analyzed to identify target volumes. Spatial sensitivity encoding can also be used to identify target volumes. After the target volumes are identified the NMR measurement technique can be used to identify their contents.

  18. Magnetic Resonance Imaging 1 A new global optimization algorithm and its application to a

    E-Print Network [OSTI]

    Neumaier, Arnold

    Magnetic Resonance Imaging 1 A new global optimization algorithm and its application to a Magnetic-cost, low-field multipolar magnet for Magnetic Resonance Imaging with a high field uniformity, the proposed method em- ploys, as local search engine, a derivative free procedure. Under reasonable

  19. Soft x-ray microscopy - a powerful analytical tool to image magnetism down to fundamental length and times scales

    E-Print Network [OSTI]

    Fischer, Peter

    2008-01-01T23:59:59.000Z

    analytical tool to image magnetism down to fundamentalmicroscopies Research of magnetism in low dimensions has notnanoscience [3]. Solid state magnetism is also a showcase in

  20. Respiratory Amplitude Guided 4-Dimensional Magnetic Resonance Imaging

    SciTech Connect (OSTI)

    Hu, Yanle, E-mail: yhu@radonc.wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States)] [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States); Caruthers, Shelton D. [Department of Medicine, Washington University School of Medicine, St. Louis, Missouri (United States)] [Department of Medicine, Washington University School of Medicine, St. Louis, Missouri (United States); Low, Daniel A. [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States)] [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States); Parikh, Parag J.; Mutic, Sasa [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States)] [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States)

    2013-05-01T23:59:59.000Z

    Purpose: To evaluate the feasibility of prospectively guiding 4-dimensional (4D) magnetic resonance imaging (MRI) image acquisition using triggers at preselected respiratory amplitudes to achieve T{sub 2} weighting for abdominal motion tracking. Methods and Materials: A respiratory amplitude-based triggering system was developed and integrated into a commercial turbo spin echo MRI sequence. Initial feasibility tests were performed on healthy human study participants. Four respiratory states, the middle and the end of inhalation and exhalation, were used to trigger 4D MRI image acquisition of the liver. To achieve T{sub 2} weighting, the echo time and repetition time were set to 75 milliseconds and 4108 milliseconds, respectively. Single-shot acquisition, together with parallel imaging and partial k-space imaging techniques, was used to improve image acquisition efficiency. 4D MRI image sets composed of axial or sagittal slices were acquired. Results: Respiratory data measured and logged by the MRI scanner showed that the triggers occurred at the appropriate respiratory levels. Liver motion could be easily observed on both 4D MRI image datasets by sensing either the change of liver in size and shape (axial) or diaphragm motion (sagittal). Both 4D MRI image datasets were T{sub 2}-weighted as expected. Conclusions: This study demonstrated the feasibility of achieving T{sub 2}-weighted 4D MRI images using amplitude-based respiratory triggers. With the aid of the respiratory amplitude-based triggering system, the proposed method is compatible with most MRI sequences and therefore has the potential to improve tumor-tissue contrast in abdominal tumor motion imaging.

  1. Slew-rate dependence of tracer magnetization response in magnetic particle imaging

    SciTech Connect (OSTI)

    Shah, Saqlain A.; Krishnan, K. M., E-mail: kannanmk@uw.edu [Materials Science and Engineering, University of Washington, Seattle, Washington 98195 (United States); Ferguson, R. M. [LodeSpin Labs, P.O. Box 95632, Seattle, Washington 98145 (United States)

    2014-10-28T23:59:59.000Z

    Magnetic Particle Imaging (MPI) is a new biomedical imaging technique that produces real-time, high-resolution tomographic images of superparamagnetic iron oxide nanoparticle tracers. Currently, 25?kHz and 20?mT/?{sub 0} excitation fields are common in MPI, but lower field amplitudes may be necessary for patient safety in future designs. Here, we address fundamental questions about MPI tracer magnetization dynamics and predict tracer performance in future scanners that employ new combinations of excitation field amplitude (H{sub o}) and frequency (?). Using an optimized, monodisperse MPI tracer, we studied how several combinations of drive field frequencies and amplitudes affect the tracer's response, using Magnetic Particle Spectrometry and AC hysteresis, for drive field conditions at 15.5, 26, and 40.2?kHz, with field amplitudes ranging from 7 to 52?mT/?{sub 0}. For both fluid and immobilized nanoparticle samples, we determined that magnetic response was dominated by Néel reversal. Furthermore, we observed that the peak slew-rate (?H{sub o}) determined the tracer magnetic response. Smaller amplitudes provided correspondingly smaller field of view, sometimes resulting in excitation of minor hysteresis loops. Changing the drive field conditions but keeping the peak slew-rate constant kept the tracer response almost the same. Higher peak slew-rates led to reduced maximum signal intensity and greater coercivity in the tracer response. Our experimental results were in reasonable agreement with Stoner-Wohlfarth model based theories.

  2. Magnetic resonance imaging of living systems by remote detection

    DOE Patents [OSTI]

    Wemmer, David; Pines, Alexander; Bouchard, Louis; Xu, Shoujun; Harel, Elad; Budker, Dmitry; Lowery, Thomas; Ledbetter, Micah

    2013-10-29T23:59:59.000Z

    A novel approach to magnetic resonance imaging is disclosed. Blood flowing through a living system is prepolarized, and then encoded. The polarization can be achieved using permanent or superconducting magnets. The polarization may be carried out upstream of the region to be encoded or at the place of encoding. In the case of an MRI of a brain, polarization of flowing blood can be effected by placing a magnet over a section of the body such as the heart upstream of the head. Alternatively, polarization and encoding can be effected at the same location. Detection occurs at a remote location, using a separate detection device such as an optical atomic magnetometer, or an inductive Faraday coil. The detector may be placed on the surface of the skin next to a blood vessel such as a jugular vein carrying blood away from the encoded region.

  3. SQUID-Detected Magnetic Resonance Imaging in MicroteslaFields

    SciTech Connect (OSTI)

    Moessle, Michael; Hatridge, Michael; Clarke, John

    2006-08-14T23:59:59.000Z

    Magnetic resonance imaging (MRI) has developed into a powerful clinical tool for imaging the human body (1). This technique is based on nuclear magnetic resonance (NMR) of protons (2, 3) in a static magnetic field B{sub 0}. An applied radiofrequency pulse causes the protons to precess about B{sub 0} at their Larmor frequency {nu}{sub 0} = ({gamma}/2{pi})B{sub 0}, where {gamma} is the gyromagnetic ratio; {gamma}/2{pi} = 42.58 MHz/tesla. The precessing protons generate an oscillating magnetic field and hence a voltage in a nearby coil that is amplified and recorded. The application of three-dimensional magnetic field gradients specifies a unique magnetic field and thus an NMR frequency in each voxel of the subject, so that with appropriate encoding of the signals one can acquire a complete image (4). Most clinical MRI systems involve magnetic fields generated by superconducting magnets, and the current trend is to higher magnetic fields than the widely used 1.5-T systems (5). Nonetheless, there is ongoing interest in the development of less expensive imagers operating at lower fields. Commercially available 0.2-T systems based on permanent magnets offer both lower cost and a more open access than their higher-field counterparts, at the expense of signal-to-noise-ratio (SNR) and spatial resolution. At the still lower field of 0.03 mT maintained by a conventional, room-temperature solenoid, Connolly and co-workers (6, 7) obtain good spatial resolution and signal-to-noise ratio (SNR) by prepolarizing the protons in a field B{sub p} of 0.3 T. Prepolarization (8) enhances the magnetic moment of an ensemble of protons over that produced by the lower precession field; after the polarizing field is removed, the higher magnetic moment produces a correspondingly larger signal during its precession in B{sub 0}. Using the same method, Stepisnik et al. (9) obtained MR images in the Earth's magnetic field ({approx} 50 {micro}T). Alternatively, one can enhance the signal amplitude in MRI using laser polarized noble gases such as {sup 3}He or {sup 129}Xe (10-12). Hyperpolarized gases were used successfully to image the human lung in fields on the order of several mT (13-15). To overcome the sensitivity loss of Faraday detection at low frequencies, ultrasensitive magnetometers based on the Superconducting QUantum Interference Device (SQUID) (16) are used to detect NMR and MRI signals (17-24). Recently, SQUID-based MRI systems capable of acquiring in vivo images have appeared. For example, in the 10-mT system of Seton et al. (18) signals are coupled to a SQUID via a superconducting tuned circuit, while Clarke and coworkers (22, 25, 26) developed a system at 132 {micro}T with an untuned input circuit coupled to a SQUID. In a quite different approach, atomic magnetometers have been used recently to detect the magnetization (27) and NMR signal (28) of hyperpolarized gases. This technique could potentially be used for low-field MRI in the future. The goal of this review is to summarize the current state-of-the-art of MRI in microtesla fields detected with SQUIDs. The principles of SQUIDs and NMR are briefly reviewed. We show that very narrow NMR linewidths can be achieved in low magnetic fields that are quite inhomogeneous, with illustrative examples from spectroscopy. After describing our ultralow-field MRI system, we present a variety of images. We demonstrate that in microtesla fields the longitudinal relaxation T{sub 1} is much more material dependent than is the case in high fields; this results in a substantial improvement in 'T{sub 1}-weighted contrast imaging'. After outlining the first attempts to combine microtesla NMR with magnetoencephalography (MEG) (29), we conclude with a discussion of future directions.

  4. Self-consistent magnetic properties of magnetite tracers optimized for magnetic particle imaging measured by ac susceptometry,

    E-Print Network [OSTI]

    Krishnan, Kannan M.

    Self-consistent magnetic properties of magnetite tracers optimized for magnetic particle imaging measured by ac susceptometry, magnetorelaxometry and magnetic particle spectroscopy Frank Ludwig a , Hilke. Krishnan b,n a Institute of Electrical Measurement and Fundamental Electrical Engineering, TU Braunschweig

  5. COSMIC-RAY CURRENT-DRIVEN TURBULENCE AND MEAN-FIELD DYNAMO EFFECT

    SciTech Connect (OSTI)

    Rogachevskii, Igor; Kleeorin, Nathan [Department of Mechanical Engineering, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 84105 (Israel); Brandenburg, Axel [NORDITA, Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden); Eichler, David [Department of Physics, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 84105 (Israel)

    2012-07-01T23:59:59.000Z

    We show that an {alpha} effect is driven by the cosmic-ray (CR) Bell instability exciting left-right asymmetric turbulence. Alfven waves of a preferred polarization have maximally helical motion, because the transverse motion of each mode is parallel to its curl. We show how large-scale Alfven modes, when rendered unstable by CR streaming, can create new net flux over any finite region, in the direction of the original large-scale field. We perform direct numerical simulations (DNSs) of a magnetohydrodynamic fluid with a forced CR current and use the test-field method to determine the {alpha} effect and the turbulent magnetic diffusivity. As follows from DNS, the dynamics of the instability has the following stages: (1) in the early stage, the small-scale Bell instability that results in the production of small-scale turbulence is excited; (2) in the intermediate stage, there is formation of larger-scale magnetic structures; (3) finally, quasi-stationary large-scale turbulence is formed at a growth rate that is comparable to that expected from the dynamo instability, but its amplitude over much longer timescales remains unclear. The results of DNS are in good agreement with the theoretical estimates. It is suggested that this dynamo is what gives weakly magnetized relativistic shocks such as those from gamma-ray bursts (GRBs) a macroscopic correlation length. It may also be important for large-scale magnetic field amplification associated with CR production and diffusive shock acceleration in supernova remnants (SNRs) and blast waves from GRBs. Magnetic field amplification by Bell turbulence in SNRs is found to be significant, but it is limited owing to the finite time available to the super-Alfvenicly expanding remnant. The effectiveness of the mechanisms is shown to be dependent on the shock velocity. Limits on magnetic field growth in longer-lived systems, such as the Galaxy and unconfined intergalactic CRs, are also discussed.

  6. Current-driven transformations of the intermediate-state patterns in type-I superconductors Jacob R. Hoberg and Ruslan Prozorov*

    E-Print Network [OSTI]

    Current-driven transformations of the intermediate-state patterns in type-I superconductors Jacob R-II superconductors each bearing a single flux quanta, tubes in type-I superconductors may contain up to approxi

  7. Current-driven flow instabilities in large-scale liquid metal batteries, and how to tame them

    E-Print Network [OSTI]

    Weber, Norbert; Stefani, Frank; Weier, Tom

    2013-01-01T23:59:59.000Z

    The use of liquid metal batteries is considered as one promising option for electric grid stabilisation. While large versions of such batteries are preferred in view of the economies of scale, they are susceptible to various magnetohydrodynamic instabilities which imply a risk of short-circuiting the battery due to the triggered fluid flow. Here we focus on the current driven Tayler instability and give critical electrical currents for its onset as well as numerical estimates for the appearing flow structures and speeds. Scaling laws for different materials, battery sizes and geometries are found. We further discuss and compare various means for preventing the instability.

  8. Abstract--Magnetic Resonance Imaging (MRI) guided nanorobotic systems that could perform diagnostic, curative

    E-Print Network [OSTI]

    Mavroidis, Constantinos

    groups have employed magnetized micro/ nanoparticles and have implemented magnetic propulsion techniquesAbstract-- Magnetic Resonance Imaging (MRI) guided nanorobotic systems that could perform on the use of a MRI scanner to induce the required external driving forces to guide magnetic nanocapsules

  9. MRI Magnetic Signature Imaging, Tracking and Navigation for Targeted Micro/Nano-capsule Therapeutics

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    - back for the microdevice and a propulsion sequence to enable interleaved magnetic propulsionMRI Magnetic Signature Imaging, Tracking and Navigation for Targeted Micro J. Nelson, Antoine Ferreira and Sergej Fatikow Abstract-- The propulsion of nano

  10. Superconducting matrix fault current limiter with current-driven trigger mechanism

    DOE Patents [OSTI]

    Yuan, Xing (Albany, NY)

    2008-04-15T23:59:59.000Z

    A modular and scalable Matrix-type Fault Current Limiter (MFCL) that functions as a "variable impedance" device in an electric power network, using components made of superconducting and non-superconducting electrically conductive materials. An inductor is connected in series with the trigger superconductor in the trigger matrix and physically surrounds the superconductor. The current surge during a fault will generate a trigger magnetic field in the series inductor to cause fast and uniform quenching of the trigger superconductor to significantly reduce burnout risk due to superconductor material non-uniformity.

  11. Linear and nonlinear dynamics of current-driven waves in dusty plasmas

    SciTech Connect (OSTI)

    Ahmad, Ali [National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology (CIIT), Islamabad (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Ali Shan, S.; Haque, Q. [National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Saleem, H. [National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology (CIIT), Islamabad (Pakistan)

    2012-09-15T23:59:59.000Z

    The linear and nonlinear dynamics of a recently proposed plasma mode of dusty plasma is studied using kappa distribution for electrons. This electrostatic wave can propagate in the plasma due to the sheared flow of electrons and ions parallel to the external magnetic field in the presence of stationary dust. The coupling of this wave with the usual drift wave and ion acoustic wave is investigated. D'Angelo's mode is also modified in the presence of superthermal electrons. In the nonlinear regime, the wave can give rise to dipolar vortex structures if the shear in flow is weaker and tripolar vortices if the flow has steeper gradient. The results have been applied to Saturn's magnetosphere corresponding to negatively charged dust grains. But the theoretical model is applicable for positively charged dust as well. This work will be useful for future observations and studies of dusty environments of planets and comets.

  12. Can Images Obtained With High Field Strength Magnetic Resonance Imaging Reduce Contouring Variability of the Prostate?

    SciTech Connect (OSTI)

    Usmani, Nawaid, E-mail: Nawaid.Usmani@albertahealthservices.ca [Department of Radiation Oncology, Cross Cancer Institute, Edmonton, AB (Canada); Department of Oncology, University of Alberta, Edmonton, AB (Canada); Sloboda, Ron [Department of Oncology, University of Alberta, Edmonton, AB (Canada); Department of Medical Physics, Cross Cancer Institute, Edmonton, AB (Canada); Kamal, Wafa [Department of Radiation Oncology, Cross Cancer Institute, Edmonton, AB (Canada); Ghosh, Sunita [Department of Oncology, University of Alberta, Edmonton, AB (Canada); Department of Experimental Oncology, Cross Cancer Institute, Edmonton, AB (Canada); Pervez, Nadeem; Pedersen, John; Yee, Don; Danielson, Brita; Murtha, Albert; Amanie, John [Department of Radiation Oncology, Cross Cancer Institute, Edmonton, AB (Canada); Department of Oncology, University of Alberta, Edmonton, AB (Canada); Monajemi, Tara [Department of Medical Physics, Cross Cancer Institute, Edmonton, AB (Canada)

    2011-07-01T23:59:59.000Z

    Purpose: The objective of this study is to determine whether there is less contouring variability of the prostate using higher-strength magnetic resonance images (MRI) compared with standard MRI and computed tomography (CT). Methods and Materials: Forty patients treated with prostate brachytherapy were accrued to a prospective study that included the acquisition of 1.5-T MR and CT images at specified time points. A subset of 10 patients had additional 3.0-T MR images acquired at the same time as their 1.5-T MR scans. Images from each of these patients were contoured by 5 radiation oncologists, with a random subset of patients repeated to quantify intraobserver contouring variability. To minimize bias in contouring the prostate, the image sets were placed in folders in a random order with all identifiers removed from the images. Results: Although there was less interobserver contouring variability in the overall prostate volumes in 1.5-T MRI compared with 3.0-T MRI (p < 0.01), there was no significant differences in contouring variability in the different regions of the prostate between 1.5-T MRI and 3.0-T MRI. MRI demonstrated significantly less interobserver contouring variability in both 1.5-T and 3.0-T compared with CT in overall prostate volumes (p < 0.01, p = 0.01), with the greatest benefits being appreciated in the base of the prostate. Overall, there was less intraobserver contouring variability than interobserver contouring variability for all of the measurements analyzed. Conclusions: Use of 3.0-T MRI does not demonstrate a significant improvement in contouring variability compared with 1.5-T MRI, although both magnetic strengths demonstrated less contouring variability compared with CT.

  13. THERMAL IMAGING OF ACTIVE MAGNETIC REGERNERATOR MCE MATERIALS DURING OPERATION

    SciTech Connect (OSTI)

    Shassere, Benjamin [ORNL] [ORNL; West, David L [ORNL] [ORNL; Abdelaziz, Omar [ORNL] [ORNL; Evans III, Boyd Mccutchen [ORNL] [ORNL

    2012-01-01T23:59:59.000Z

    An active magnetic regenerator (AMR) prototype was constructed that incorporates a Gd sheet into the regenerator wall to enable visualization of the system s thermal transients. In this experiment, the thermal conditions inside the AMR are observed under a variety of operating conditions. An infrared (IR) camera is employed to visualize the thermal transients within the AMR. The IR camera is used to visually and quantitatively evaluate the temperature difference and thus giving means to calculate the performance of the system under the various operating conditions. Thermal imaging results are presented for two differing experimental test runs. Real time imaging of the thermal state of the AMR has been conducted while operating the system over a range of conditions. A 1 Tesla twin-coil electromagnet (situated on a C frame base) is used for this experiment such that all components are stationary during testing. A modular, linear reciprocating system has been realized in which the effects of regenerator porosity and utilization factor can be investigated. To evaluate the performance variation in porosity and utilization factor the AMR housing was constructed such that the plate spacing of the Gd sheets may be varied. Each Gd sheet has dimensions of 38 mm wide and 66 mm long with a thickness of 1 mm and the regenerator can hold a maximum of 29 plates with a spacing of 0.25 mm. Quantitative and thermal imaging results are presented for several regenerator configurations.

  14. Particle in cell simulations of Buneman instability of a current-driven plasma with q-nonextensive electron velocity distribution

    SciTech Connect (OSTI)

    Niknam, A. R., E-mail: a-niknam@sbu.ac.ir; Roozbahani, H.; Komaizi, D. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of); Hashemzadeh, M. [Faculty of Physics, Shahrood University, Shahrood (Iran, Islamic Republic of)

    2014-09-15T23:59:59.000Z

    The nonlinear evolution of low frequency Buneman instability in an unmagnetized current-driven plasma with q-nonextensive electron velocity distribution is investigated using particle in cell simulation. Simulation results show that the generation of electron phase space holes and the counter-streaming current induced in the plasma strongly depend on the q-parameter. It is found that by increasing the nonextensive parameter, the distribution of electron density becomes highly peaked. This density steepening or grating-like pattern occurs at the saturation time. In addition, a generalized dispersion relation is obtained using the kinetic theory. Analysis of the dispersion relation and the temporal evolution of the electric field energy density reveal that the growth rate of instability increases by increasing the q-parameter. Finally, the results of Maxwellian and q-nonextensive velocity distributions have been compared and discussed.

  15. Abstract-In this study, imaging of electrical current density in conducting objects, which contain nuclear magnetic resonance

    E-Print Network [OSTI]

    Eyüboðlu, Murat

    nuclear magnetic resonance (NMR) active nuclei is planned using 0.15T Magnetic Resonance Imaging (MRI at each cycle within the object. The applied current pulse creates a measurable magnetic flux density. The component of magnetic flux density parallel to the main magnetic field accumulates an additional phase

  16. Wavelet smoothing of functional magnetic resonance images: A ...

    E-Print Network [OSTI]

    1910-30-72T23:59:59.000Z

    The two types of images are then compared; the regions where there are significant ... techniques at various stages in the production of the magnitude images.

  17. HST.583 Functional Magnetic Resonance Imaging: Data Acquisition and Analysis, Fall 2006

    E-Print Network [OSTI]

    Gollub, Randy L.

    This team taught, multidisciplinary course covers the fundamentals of magnetic resonance imaging relevant to the conduct and interpretation of human brain mapping studies. The challenges inherent in advancing our knowledge ...

  18. A 16-Channel Receive Array Insert for Magnetic Resonance Imaging of the Breast at 7T

    E-Print Network [OSTI]

    By, Samantha

    2014-04-01T23:59:59.000Z

    Breast cancer is the second leading cause of cancer death among females in the United States. Magnetic resonance imaging (MRI) has emerged as a powerful tool for detecting and evaluating the disease, with notable advantages over other modalities...

  19. An iterative technique for refinement of selective excitations for magnetic resonance imaging

    E-Print Network [OSTI]

    Lebsack, Eliot Todd

    1999-01-01T23:59:59.000Z

    Selective RF pulses are needed or many application in magnetic resonance imaging (MRI). The desired excitation profile is omen used as the spectrum of the applied RF pulse; the modulation waveform of the RF pulse which approximately excites...

  20. T2*-weighted magnetic resonance imaging used to detect coagulative necrosis in tissue

    E-Print Network [OSTI]

    Van Hyfte, John Bruce

    1997-01-01T23:59:59.000Z

    to prevent unnecessary collateral damage to surrounding healthy tissue. This research focuses on using T2*-weighted FLASH magnetic resonance imaging to detect irreversible changes in i . n vitro bovine liver tissue and tissuesimulating polyacrylamide gel...

  1. Eight-Channel Head Array and Control System for Parallel Transmit/Receive Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Moody, Katherine

    2014-08-11T23:59:59.000Z

    Interest in magnetic resonance imaging (MRI) at high fields strengths (3 Tesla and above) is driven by the associated improvements in signal-to-noise ratio and spectral resolution. In practice, however, technical challenges prevent these benefits...

  2. Multimodal neuroimaging with simultaneous electroencephalogram and high-field functional magnetic resonance imaging

    E-Print Network [OSTI]

    Purdon, Patrick L. (Patrick Lee), 1974-

    2005-01-01T23:59:59.000Z

    Simultaneous recording of electroencephalogram (EEG) and functional magnetic resonance imaging (tMRI) is an important emerging tool in functional neuroimaging with the potential to reveal new mechanisms for brain function ...

  3. Classification of brain compartments and head injury lesions by neural networks applied to magnetic resonance images

    E-Print Network [OSTI]

    Kischell, Eric Robert

    1993-01-01T23:59:59.000Z

    ' (Member) A. D. Patton ( ead of epartment) August 1993 Major Subject: Electrical Engineering ABSTRACT Classification of Brain Compartments and Head Injury Lesions by Neural Networks Applied to Magnetic Resonance Images. (August 1993) Eric Robert... Kischell, B. S. , Northeastern University Chair of Advisory Committee: Dr. Nasser Kehtarnavaz An automatic neural network-based approach was ap- plied to segment brain compartments and closed-head-injury lesions in magnetic resonance (MR) images Two...

  4. The development of magnetic resonance imaging for the determination of porosity in reservoir core samples

    E-Print Network [OSTI]

    Sherman, Byron Blake

    1991-01-01T23:59:59.000Z

    THE DEVELOPMENT OF MAGNETIC RESONANCE IMAGING FOR THE DETERMINATION OF POROSITY IN RESERVOIR CORE SAMPLES A Thesis by BYRON BLAKE SHERMAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1991 Major Subject: Petroleum Engineering THE DEVELOPMENT OF MAGNETIC RESONANCE IMAGING FOR THE DETERMINATION OF POROSITY IN RESERVOIR CORE SAMPLES A Thesis by BYRON BLAKE SHERMAN Approved...

  5. Application of nuclear magnetic resonance imaging and spectroscopy to fluids in porous media

    E-Print Network [OSTI]

    Mandava, Shanthi Sree

    1991-01-01T23:59:59.000Z

    APPLICATION OF NUCLEAR MAGNETIC RESONANCE IMAGING AND SPECTROSCOPY TO FLUIDS IN POROUS MEDIA A Thesis by SHANTHI SREE MANDAVA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE May 1991 Major Subject: Chemical Engineering APPLICATION OF NUCLEAR MAGNETIC RESONANCE IMAGING AND SPECTROSCOPY TO FLUIDS IN POROUS MEDIA A Thesis by SHANTHI SREE MANDAVA Approved as to style and content by: A. Ted...

  6. A REAL TIME 3D VISUALIZATION PROTOTYPE FOR INTERVENTIONAL MAGNETIC RESONANCE IMAGING

    E-Print Network [OSTI]

    Schumann, Heidrun

    A REAL TIME 3D VISUALIZATION PROTOTYPE FOR INTERVENTIONAL MAGNETIC RESONANCE IMAGING JENS FISCHER­invasive examinations. This prototype allows simultaneous visualization of three different types of data: a 3D­Magnetic@informatik.uni­rostock.de Abstract: This paper describes a prototype of a visualization system which is designed to support

  7. Blood-flow magnetic resonance imaging of the retina Yingxia Li,a,1

    E-Print Network [OSTI]

    Duong, Timothy Q.

    Blood-flow magnetic resonance imaging of the retina Yingxia Li,a,1 Haiying Cheng,a,1 and Timothy Q 1 November 2007 This study describes a novel MRI application to image basal blood flow, physiologically induced blood-flow changes, and the effects of isoflurane concentration on blood flow

  8. Microfluidically Cryo-Cooled Planar Coils for Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Koo, Chiwan

    2013-08-09T23:59:59.000Z

    is approximately the same as the diameters of the microcoils. Here microfluidic technology is utilized to locally cryo-cool the microcoils and minimize the thermal isolation gap so that the imaging surface is within the imaging depth of the microcoils. The first...

  9. Motion of free spins and NMR imaging without a radio-frequency magnetic field

    E-Print Network [OSTI]

    Kees van Schenk Brill; Jassem Lahfadi; Tarek Khalil; Daniel Grucker

    2015-04-19T23:59:59.000Z

    NMR imaging without any radio-frequency magnetic field is explained by a quantum treatment of independent spin~$\\tfrac 12$. The total magnetization is determined by means of their individual wave function. The theoretical treatment, based on fundamental axioms of quantum mechanics and solving explicitly the Schr\\"{o}dinger equation with the kinetic energy part which gives the motion of free spins, is recalled. It explains the phase shift of the spin noise spectrum with its amplitude compared to the conventional NMR spectrum. Moreover it explains also the relatively good signal to noise ratio of NMR images obtained without a RF pulse. This derivation should be helpful for new magnetic resonance imaging sequences or for developing quantum computing by NMR.

  10. Simultaneous Electroencephalography and Functional Magnetic Resonance Imaging of General Anesthesia

    E-Print Network [OSTI]

    Purdon, Patrick Lee

    It has been long appreciated that anesthetic drugs induce stereotyped changes in electroencephalogram (EEG), but the relationships between the EEG and underlying brain function remain poorly understood. Functional imaging ...

  11. RF Pulse Design for Parallel Excitation in Magnetic Resonance Imaging 

    E-Print Network [OSTI]

    Liu, Yinan

    2012-07-16T23:59:59.000Z

    , such as accelerating imaging speed, mitigating field inhomogeneity in high-field MRI, and alleviating the susceptibility artifact in functional MRI (fMRI). In these applications, controlling radiofrequency (RF) power deposition (quantified by Specific Absorption Rate...

  12. Magnetic charge crystals imaged in artificial spin ice

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love YouTokamak| NationalMagneticMagnetic

  13. 3D and 4D magnetic susceptibility tomography based on complex MR images

    DOE Patents [OSTI]

    Chen, Zikuan; Calhoun, Vince D

    2014-11-11T23:59:59.000Z

    Magnetic susceptibility is the physical property for T2*-weighted magnetic resonance imaging (T2*MRI). The invention relates to methods for reconstructing an internal distribution (3D map) of magnetic susceptibility values, .chi. (x,y,z), of an object, from 3D T2*MRI phase images, by using Computed Inverse Magnetic Resonance Imaging (CIMRI) tomography. The CIMRI technique solves the inverse problem of the 3D convolution by executing a 3D Total Variation (TV) regularized iterative convolution scheme, using a split Bregman iteration algorithm. The reconstruction of .chi. (x,y,z) can be designed for low-pass, band-pass, and high-pass features by using a convolution kernel that is modified from the standard dipole kernel. Multiple reconstructions can be implemented in parallel, and averaging the reconstructions can suppress noise. 4D dynamic magnetic susceptibility tomography can be implemented by reconstructing a 3D susceptibility volume from a 3D phase volume by performing 3D CIMRI magnetic susceptibility tomography at each snapshot time.

  14. Distortion-free magnetic resonance imaging in the zero-field limit

    SciTech Connect (OSTI)

    Kelso, Nathan; Lee, Seung-Kyun; Bouchard, Louis-S.; Demas, Vasiliki; Muck, Michael; Pines, Alexander; Clarke, John

    2009-07-09T23:59:59.000Z

    MRI is a powerful technique for clinical diagnosis and materials characterization. Images are acquired in a homogeneous static magnetic field much higher than the fields generated across the field of view by the spatially encoding field gradients. Without such a high field, the concomitant components of the field gradient dictated by Maxwell's equations lead to severe distortions that make imaging impossible with conventional MRI encoding. In this paper, we present a distortion-free image of a phantom acquired with a fundamentally different methodology in which the applied static field approaches zero. Our technique involves encoding with pulses of uniform and gradient field, and acquiring the magnetic field signals with a SQUID. The method can be extended to weak ambient fields, potentially enabling imaging in the Earth's field without cancellation coils or shielding. Other potential applications include quantum information processing and fundamental studies of long-range ferromagnetic interactions.

  15. Potential Applications of Microtesla Magnetic Resonance ImagingDetected Using a Superconducting Quantum Interference Device

    SciTech Connect (OSTI)

    Myers, Whittier R.

    2006-05-18T23:59:59.000Z

    This dissertation describes magnetic resonance imaging (MRI) of protons performed in a precession field of 132 {micro}T. In order to increase the signal-to-noise ratio (SNR), a pulsed 40-300 mT magnetic field prepolarizes the sample spins and an untuned second-order superconducting gradiometer coupled to a low transition temperature superconducting quantum interference device (SQUID) detects the subsequent 5.6-kHz spin precession. Imaging sequences including multiple echoes and partial Fourier reconstruction are developed. Calculating the SNR of prepolarized SQUID-detected MRI shows that three-dimensional Fourier imaging yields higher SNR than slice-selection imaging. An experimentally demonstrated field-cycling pulse sequence and post-processing algorithm mitigate image artifacts caused by concomitant gradients in low-field MRI. The magnetic field noise of SQUID untuned detection is compared to the noise of SQUID tuned detection, conventional Faraday detection, and the Nyquist noise generated by conducting biological samples. A second-generation microtesla MRI system employing a low-noise SQUID is constructed to increase SNR. A 2.4-m cubic, eddy-current shield with 6-mm thick aluminum walls encloses the experiment to attenuate external noise. The measured noise is 0.75 fT Hz{sup -1/2} referred to the bottom gradiometer loop. Solenoids wound from 30-strand braided wire to decrease Nyquist noise and cooled by either liquid nitrogen or water polarize the spins. Copper wire coils wound on wooden supports produce the imaging magnetic fields and field gradients. Water phantom images with 0.8 x 0.8 x 10 mm{sup 3} resolution have a SNR of 6. Three-dimensional 1.6 x 1.9 x 14 mm{sup 3} images of bell peppers and 3 x 3 x 26 mm{sup 3} in vivo images of the human arm are presented. Since contrast based on the transverse spin relaxation rate (T{sub 1}) is enhanced at low magnetic fields, microtesla MRI could potentially be used for tumor imaging. The measured T{sub 1} of ex vivo normal and cancerous prostate tissue differ significantly at 132 {micro}T. A single-sided MRI system designed for prostate imaging could achieve 3 x 3 x 5 mm{sup 3} resolution in 8 minutes. Existing SQUID-based magnetoencephalography (MEG) systems could be used as microtesla MRI detectors. A commercial 275-channel MEG system could acquire 6-minute brain images with (4 mm){sup 3} resolution and SNR 16.

  16. X-ray imaging of extended magnetic domain walls in Ni80Fe20 wires

    SciTech Connect (OSTI)

    Basu, S.; Fry, P. W.; Allwood, D. A.; Bryan, M. T.; Gibbs, M. R. J.; Schrefl, T.; Im, M.-Y.; Fischer, P.

    2009-06-20T23:59:59.000Z

    We have used magnetic transmission X-ray microscopy to image magnetization configurations in 700 nm wide Ni{sub 80}Fe{sub 20} planar wires attached to 'nucleation' pads Domain walls were observed to inject only across half of the wire width but extend to several micrometers in length. Magnetostatic interactions with adjacent wires caused further unusual domain wall behavior. Micromagnetic modeling suggests the extended walls have Neel-like structure along their length and indicates weaker exchange coupling than is often assumed. These observations explain previous measurements of domain wall injection and demonstrate that magnetic domain walls in larger nanowires cannot always be considered as localized entities.

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

    E-Print Network [OSTI]

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

    2015-01-01T23:59:59.000Z

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

  18. The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Magnetohydrodynamics Simulation Module for the Global Solar Corona

    E-Print Network [OSTI]

    Hayashi, Keiji; Liu, Yang; Bobra, Monica G; Sun, Xudong D; Norton, Aimee A

    2015-01-01T23:59:59.000Z

    Time-dependent three-dimensional magnetohydrodynamics (MHD) simulation modules are implemented at the Joint Science Operation Center (JSOC) of Solar Dynamics Observatory (SDO). The modules regularly produce three-dimensional data of the time-relaxed minimum-energy state of the solar corona using global solar-surface magnetic-field maps created from Helioseismic Magnetic Imager (HMI) full-disk magnetogram data. With the assumption of polytropic gas with specific heat ratio of 1.05, three types of simulation products are currently generated: i) simulation data with medium spatial resolution using the definitive calibrated synoptic map of the magnetic field with a cadence of one Carrington rotation, ii) data with low spatial resolution using the definitive version of the synchronic frame format of the magnetic field, with a cadence of one day, and iii) low-resolution data using near-real-time (NRT) synchronic format of the magnetic field on daily basis. The MHD data available in the JSOC database are three-dimen...

  19. Layer resolved magnetic domain imaging of epitaxial heterostructures in large applied magnetic fields

    E-Print Network [OSTI]

    Zohar, S.; Choi, Y.; Love, D. M.; Mansell, R.; Barnes, C. H. W.; Keavney, D. J.; Rosenberg, R. A.

    2015-02-19T23:59:59.000Z

    We use X-ray Excited Luminescence Microscopy to investigate the elemental and layer resolved magnetic reversal in an interlayer exchange coupled (IEC) epitaxial Fe/Cr wedge/Co heterostructure. The transition from strongly coupled parallel Co...

  20. GPU-accelerated denoising of 3D magnetic resonance images

    SciTech Connect (OSTI)

    Howison, Mark; Wes Bethel, E.

    2014-05-29T23:59:59.000Z

    The raw computational power of GPU accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. In practice, applying these filtering operations requires setting multiple parameters. This study was designed to provide better guidance to practitioners for choosing the most appropriate parameters by answering two questions: what parameters yield the best denoising results in practice? And what tuning is necessary to achieve optimal performance on a modern GPU? To answer the first question, we use two different metrics, mean squared error (MSE) and mean structural similarity (MSSIM), to compare denoising quality against a reference image. Surprisingly, the best improvement in structural similarity with the bilateral filter is achieved with a small stencil size that lies within the range of real-time execution on an NVIDIA Tesla M2050 GPU. Moreover, inappropriate choices for parameters, especially scaling parameters, can yield very poor denoising performance. To answer the second question, we perform an autotuning study to empirically determine optimal memory tiling on the GPU. The variation in these results suggests that such tuning is an essential step in achieving real-time performance. These results have important implications for the real-time application of denoising to MR images in clinical settings that require fast turn-around times.

  1. Direct imaging of neural currents using ultra-low field magnetic resonance techniques

    DOE Patents [OSTI]

    Volegov, Petr L. (Los Alamos, NM); Matlashov, Andrei N. (Los Alamos, NM); Mosher, John C. (Los Alamos, NM); Espy, Michelle A. (Los Alamos, NM); Kraus, Jr., Robert H. (Los Alamos, NM)

    2009-08-11T23:59:59.000Z

    Using resonant interactions to directly and tomographically image neural activity in the human brain using magnetic resonance imaging (MRI) techniques at ultra-low field (ULF), the present inventors have established an approach that is sensitive to magnetic field distributions local to the spin population in cortex at the Larmor frequency of the measurement field. Because the Larmor frequency can be readily manipulated (through varying B.sub.m), one can also envision using ULF-DNI to image the frequency distribution of the local fields in cortex. Such information, taken together with simultaneous acquisition of MEG and ULF-NMR signals, enables non-invasive exploration of the correlation between local fields induced by neural activity in cortex and more `distant` measures of brain activity such as MEG and EEG.

  2. A cryogen-free ultralow-field superconducting quantum interference device magnetic resonance imaging system

    SciTech Connect (OSTI)

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob, E-mail: ihahn@caltech.edu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

    2014-09-15T23:59:59.000Z

    Magnetic resonance imaging (MRI) at microtesla fields using superconducting quantum interference device (SQUID) detection has previously been demonstrated, and advantages have been noted. Although the ultralow-field SQUID MRI technique would not need the heavy superconducting magnet of conventional MRI systems, liquid helium required to cool the low-temperature detector still places a significant burden on its operation. We have built a prototype cryocooler-based SQUID MRI system that does not require a cryogen. The SQUID detector and the superconducting gradiometer were cooled down to 3.7 K and 4.3 K, respectively. We describe the prototype design, characterization, a phantom image, and areas of further improvements needed to bring the imaging performance to parity with conventional MRI systems.

  3. Rotating-frame gradient fields for magnetic resonance imaging and nuclear magnetic resonance in low fields

    DOE Patents [OSTI]

    Bouchard, Louis-Serge; Pines, Alexander; Demas, Vasiliki

    2014-01-21T23:59:59.000Z

    A system and method for Fourier encoding a nuclear magnetic resonance (NMR) signal is disclosed. A static magnetic field B.sub.0 is provided along a first direction. An NMR signal from the sample is Fourier encoded by applying a rotating-frame gradient field B.sub.G superimposed on the B.sub.0, where the B.sub.G comprises a vector component rotating in a plane perpendicular to the first direction at an angular frequency .omega.in a laboratory frame. The Fourier-encoded NMR signal is detected.

  4. Modeling Left Ventricle Wall Motion Using Tagged Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Alenezy, Mohammed D.

    2009-04-17T23:59:59.000Z

    can be calculated as M = ?nullN 2 tanh( ?nullB 0 2kT ) (2.3) In a biological sample that contains about 1mL of water, there are about 10 22 hydrogen nuclei, and at the room... population that is frequently in need of quality tomographic images for the assessment of congenital heart defects. MRI can characterize myocardial function through the use of cine MRI and tagged MRI. The latter provides a means to assess wall motion...

  5. Novel Hall sensors developed for magnetic field imaging systems.

    SciTech Connect (OSTI)

    Cambel, V.; Karapetrov, G.; Novosad, V.; Bartolome, E.; Gregusova, D.; Fedor, J.; Kudela, R.; Soltys, J.; Materials Science Division; Slovak Academy of Sciences; Univ. Autonoma de Barcelona

    2007-09-01T23:59:59.000Z

    We report here on the fabrication and application of novel planar Hall sensors based on shallow InGaP/AlGaAs/GaAs heterostructure with a two-dimensional electron gas (2DEG) as an active layer. The sensors are developed for two kinds of experiments. In the first one, magnetic samples are placed directly on the Hall sensor. Room temperature experiments of permalloy objects evaporated onto the sensor are presented. In the second experiment, the sensor scans close over a multigranular superconducting sample prepared on a YBCO thin film. Large-area and high-resolution scanning experiments were performed at 4.2 K with the Hall probe scanning system in a liquid helium flow cryostat.

  6. Single-Shot Magnetic Resonance Spectroscopic Imaging with Partial Parallel Imaging

    E-Print Network [OSTI]

    spectroscopic imaging (MRSI) pulse se- quence based on proton­echo-planar-spectroscopic-imaging (PEPSI. Comparison with conventional PEPSI and PEPSI with fourfold SENSE accelera- tion demonstrated comparable-acetyl-aspartate (NAA) in vivo with concentration values in the ranges measured with conventional PEPSI and SENSE

  7. Nuclear magnetic resonance imaging of water content in the subsurface

    SciTech Connect (OSTI)

    J. Hendricks; T. Yao; A. Kearns

    1999-01-21T23:59:59.000Z

    Previous theoretical and experimental studies indicated that surface nuclear magnetic resonance (NMR) has the potential to provide cost-effective water content measurements in the subsurface and is a technology ripe for exploitation in practice. The objectives of this investigation are (a) to test the technique under a wide range of hydrogeological conditions and (b) to generalize existing NMR theories in order to correctly model NMR response from conductive ground and to assess properties of the inverse problem. Twenty-four sites with different hydrogeologic settings were selected in New Mexico and Colorado for testing. The greatest limitation of surface NMR technology appears to be the lack of understanding in which manner the NMR signal is influenced by soil-water factors such as pore size distribution, surface-to-volume ratio, paramagnetic ions dissolved in the ground water, and the presence of ferromagnetic minerals. Although the theoretical basis is found to be sound, several advances need to be made to make surface NMR a viable technology for hydrological investigations. There is a research need to investigate, under controlled laboratory conditions, how the complex factors of soil-water systems affect NMR relaxation times.

  8. Three dimensional nuclear magnetic resonance spectroscopic imaging of sodium ions using stochastic excitation and oscillating gradients

    SciTech Connect (OSTI)

    Frederick, B.deB. [California Univ., Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States)

    1994-12-01T23:59:59.000Z

    Nuclear magnetic resonance (NMR) spectroscopic imaging of {sup 23}Na holds promise as a non-invasive method of mapping Na{sup +} distributions, and for differentiating pools of Na{sup +} ions in biological tissues. However, due to NMR relaxation properties of {sup 23}Na in vivo, a large fraction of Na{sup +} is not visible with conventional NMR imaging methods. An alternate imaging method, based on stochastic excitation and oscillating gradients, has been developed which is well adapted to measuring nuclei with short T{sub 2}. Contemporary NMR imaging techniques have dead times of up to several hundred microseconds between excitation and sampling, comparable to the shortest in vivo {sup 23}Na T{sub 2} values, causing significant signal loss. An imaging strategy based on stochastic excitation has been developed which greatly reduces experiment dead time by reducing peak radiofrequency (RF) excitation power and using a novel RF circuit to speed probe recovery. Continuously oscillating gradients are used to eliminate transient eddy currents. Stochastic {sup 1}H and {sup 23}Na spectroscopic imaging experiments have been performed on a small animal system with dead times as low as 25{mu}s, permitting spectroscopic imaging with 100% visibility in vivo. As an additional benefit, the encoding time for a 32x32x32 spectroscopic image is under 30 seconds. The development and analysis of stochastic NMR imaging has been hampered by limitations of the existing phase demodulation reconstruction technique. Three dimensional imaging was impractical due to reconstruction time, and design and analysis of proposed experiments was limited by the mathematical intractability of the reconstruction method. A new reconstruction method for stochastic NMR based on Fourier interpolation has been formulated combining the advantage of a several hundredfold reduction in reconstruction time with a straightforward mathematical form.

  9. K-space reconstruction of magnetic resonance inverse imaging (K-InI) of human visuomotor systems

    E-Print Network [OSTI]

    MRI InI Visual MRI Neuroimaging K-InI Inverse solution MEG EEG Electroencephalography channels of a radio-frequency coil array, magnetic resonance inverse imaging (InI) can achieve ultra. Mathematically, the InI reconstruction is a generalization of parallel MRI (pMRI), which includes image space

  10. A Simple and Fast Iterative Soft-thresholding Algorithm for Tight Frames in Compressed Sensing Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Liu, Yunsong; Cai, Jian-Feng; Guo, Di; Chen, Zhong; Qu, Xiaobo

    2015-01-01T23:59:59.000Z

    Compressed sensing has shown great potentials in accelerating magnetic resonance imaging. Fast image reconstruction and high image quality are two main issues faced by this new technology. It has been shown that, redundant image representations, e.g. tight frames, can significantly improve the image quality. But how to efficiently solve the reconstruction problem with these redundant representation systems is still challenging. This paper attempts to address the problem of applying fast iterative soft-thresholding algorithm (FISTA) to tight frames based magnetic resonance image reconstruction. By introducing the canonical dual frame, we construct an orthogonal projection operator on the range of the analysis sparsity operator and propose a new algorithm, called the projected FISTA (pFISTA). We theoretically prove that pFISTA converges to the minimum of a function with a balanced tight frame sparsity. One major advantage of pFISTA is that only one extra parameter, the step size, is introduced and the numerical...

  11. Noise-Produced Patterns in Images Constructed from Magnetic Flux Leakage Data

    E-Print Network [OSTI]

    Pimenova, Anastasiya V; Levesley, Jeremy; Elkington, Peter; Bacciarelli, Mark

    2015-01-01T23:59:59.000Z

    Magnetic flux leakage measurements help identify the position, size and shape of corrosion-related defects in steel casings used to protect boreholes drilled into oil and gas reservoirs. Images constructed from magnetic flux leakage data contain patterns related to noise inherent in the method. We investigate the patterns and their scaling properties for the case of delta-correlated input noise, and consider the implications for the method's ability to resolve defects. The analytical evaluation of the noise-produced patterns is made possible by model reduction facilitated by large-scale approximation. With appropriate modification, the approach can be employed to analyze noise-produced patterns in other situations where the data of interest are not measured directly, but are related to the measured data by a complex linear transform involving integrations with respect to spatial coordinates.

  12. Development of Nuclear Magnetic Resonance Imaging/spectroscopy for improved petroleum recovery. Final report

    SciTech Connect (OSTI)

    Barrufet, M.A.; Flumerfelt, F.W.; Walsh, M.P.; Watson, A.T.

    1994-04-01T23:59:59.000Z

    The overall objectives of this program are to develop and apply Nuclear Magnetic Resonance Imaging (NMRI) and CT X-Ray Scanning methods for determining rock, fluid, and petrophysical properties and for fundamental studies of multiphase flow behavior in porous media. Specific objectives are divided into four subtasks: (1) development of NMRI and CT scanning for the determination of rock-fluid and petrophysical properties; (2) development of NMRI and CT scanning for characterizing conventional multiphase displacement processes; (3) development of NMR and CT scanning for characterizing dispersed phase processes; and (4) miscible displacement studies.

  13. Imaging and spectroscopic observations of magnetic reconnection and chromospheric evaporation in a solar flare

    E-Print Network [OSTI]

    Tian, Hui; Reeves, Katharine K; Raymond, John C; Guo, Fan; Liu, Wei; Chen, Bin; Murphy, Nicholas A

    2014-01-01T23:59:59.000Z

    Magnetic reconnection is believed to be the dominant energy release mechanism in solar flares. The standard flare model predicts both downward and upward outflow plasmas with speeds close to the coronal Alfv\\'{e}n speed. Yet, spectroscopic observations of such outflows, especially the downflows, are extremely rare. With observations of the newly launched Interface Region Imaging Spectrograph (IRIS), we report the detection of greatly redshifted ($\\sim$125 km s$^{-1}$ along line of sight) Fe {\\sc{xxi}} 1354.08\\AA{} emission line with a $\\sim$100 km s$^{-1}$ nonthermal width at the reconnection site of a flare. The redshifted Fe {\\sc{xxi}} feature coincides spatially with the loop-top X-Ray source observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). We interpret this large redshift as the signature of downward-moving reconnection outflow/hot retracting loops. Imaging observations from both IRIS and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) also...

  14. Image-Based Monitoring of Magnetic Resonance-Guided Thermoablative Therapies for Liver Tumors

    SciTech Connect (OSTI)

    Rempp, Hansjoerg, E-mail: hansjoerg.rempp@med.uni-tuebingen.de; Clasen, Stephan [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Pereira, Philippe L. [SLK-Kliniken, Clinic for Radiology, Nuclear Medicine, and Minimal Invasive Therapies (Germany)

    2012-12-15T23:59:59.000Z

    Minimally invasive treatment options for liver tumor therapy have been increasingly used during the last decade because their benefit has been proven for primary and inoperable secondary liver tumors. Among these, radiofrequency ablation has gained widespread consideration. Optimal image-guidance offers precise anatomical information, helps to position interventional devices, and allows for differentiation between already-treated and remaining tumor tissue. Patient safety and complete ablation of the entire tumor are the overriding objectives of tumor ablation. These may be achieved most elegantly with magnetic resonance (MR)-guided therapy, where monitoring can be performed based on precise soft-tissue imaging and additional components, such as diffusion-weighted imaging and temperature mapping. New MR scanner types and newly developed sequence techniques have enabled MR-guided intervention to move beyond the experimental phase. This article reviews the current role of MR imaging in guiding radiofrequency ablation. Signal characteristics of primary and secondary liver tumors are identified, and signal alteration during therapy is described. Diffusion-weighted imaging (DWI) and temperature mapping as special components of MR therapy monitoring are introduced. Practical information concerning coils, sequence selection, and parameters, as well as sequence gating, is given. In addition, sources of artifacts are identified and techniques to decrease them are introduced, and the characteristic signs of residual tumor in T1-, T2-, and DWI are described. We hope to enable the reader to choose MR sequences that allow optimal therapy monitoring depending on the initial signal characteristics of the tumor as well as its size and location in the liver.

  15. Neuroimaging at 1.5 T and 3.0 T: Comparison of Oxygenation-Sensitive Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Glover, Gary H.

    Neuroimaging at 1.5 T and 3.0 T: Comparison of Oxygenation-Sensitive Magnetic Resonance Imaging of the human brain at 1.5 and 3.0 T. At the higher field spiral gradient-echo (GRE) brain images revealed and becomes a larger fraction of the total noise at 3.0 T. Activation of the primary motor and visual cortex

  16. A 64-channel personal computer based image reconstruction system and applications in single echo acquisition magnetic resonance elastography and ultra-fast magnetic resonance imaging.

    E-Print Network [OSTI]

    Yallapragada, Naresh

    2009-05-15T23:59:59.000Z

    , this value is 2? x 42.5759 MHz/Tesla. This translates to a Larmor frequency of 200.238 MHz for the 4.7T magnet situated in the Magnetic Resonance Systems Lab (MRSL). In the presence of the static ????the proton population aligns itself according...

  17. Pulmonary Hemorrhage: Imaging with a New Magnetic Resonance Blood Pool Agent in Conjunction with Breathheld Three-Dimensional Magnetic Resonance Angiography

    SciTech Connect (OSTI)

    Weishaupt, Dominik; Hilfiker, Paul R.; Schmidt, Michaela; Debatin, Joerg F. [Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland)

    1999-07-15T23:59:59.000Z

    Purpose: To describe the three-dimensional magnetic resonance angiography (3D MRA) imaging appearance of the pulmonary arteries following administration of a superparamagnetic iron oxide blood pool agent to human volunteers, and to demonstrate in an animal model (pigs) how this technique can be used to detect pulmonary parenchymal hemorrhage. Methods: Two volunteers were examined following the intravenous administration of a superparamagnetic iron oxide blood pool agent (NC100150 Injection, Nycomed Amersham Imaging, Wayne, PA, USA). T1-weighted 3D gradient recalled echo (GRE) image sets (TR/TE 5.1/1.4 msec, flip angle 30 deg.) were acquired breathheld over 24 sec. To assess the detectability of pulmonary bleeding with intravascular MR contrast, pulmonary parenchymal injuries were created in two animals under general anesthesia, and fast T1-weighted 3D GRE image sets collected before and after the injury. Results: Administration of the intravascular contrast in the two volunteers resulted in selective enhancement of the pulmonary vasculature permitting complete visualization and excellent delineation of central, segmental, and subsegmental arteries. Following iatrogenic injury in the two animals, pulmonary hemorrhage was readily detected on the 3D image sets. Conclusion: The data presented illustrate that ultrafast 3D GRE MR imaging in conjunction with an intravenously administered intravascular blood pool agent can be used to perform high-quality pulmonary MRA as well as to detect pulmonary hemorrhage.

  18. Automatic Landmarking of Magnetic Resonance brain Images Camille Izard*a,b, Bruno M. Jedynaka,b and Craig E.L. Starkc

    E-Print Network [OSTI]

    Jedynak, Bruno M.

    Automatic Landmarking of Magnetic Resonance brain Images Camille Izard*a,b, Bruno M. JedynakaDepartment of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD ABSTRACT Landmarking MR images is crucial in registering brain structures from different images. It consists in locating the voxel

  19. Prediction of Liver Function by Using Magnetic Resonance-based Portal Venous Perfusion Imaging

    SciTech Connect (OSTI)

    Cao Yue, E-mail: yuecao@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Wang Hesheng [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)] [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Johnson, Timothy D. [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States)] [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States); Pan, Charlie [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)] [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Hussain, Hero [Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States)] [Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Balter, James M.; Normolle, Daniel; Ben-Josef, Edgar; Ten Haken, Randall K.; Lawrence, Theodore S.; Feng, Mary [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)] [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2013-01-01T23:59:59.000Z

    Purpose: To evaluate whether liver function can be assessed globally and spatially by using volumetric dynamic contrast-enhanced magnetic resonance imaging MRI (DCE-MRI) to potentially aid in adaptive treatment planning. Methods and Materials: Seventeen patients with intrahepatic cancer undergoing focal radiation therapy (RT) were enrolled in institution review board-approved prospective studies to obtain DCE-MRI (to measure regional perfusion) and indocyanine green (ICG) clearance rates (to measure overall liver function) prior to, during, and at 1 and 2 months after treatment. The volumetric distribution of portal venous perfusion in the whole liver was estimated for each scan. We assessed the correlation between mean portal venous perfusion in the nontumor volume of the liver and overall liver function measured by ICG before, during, and after RT. The dose response for regional portal venous perfusion to RT was determined using a linear mixed effects model. Results: There was a significant correlation between the ICG clearance rate and mean portal venous perfusion in the functioning liver parenchyma, suggesting that portal venous perfusion could be used as a surrogate for function. Reduction in regional venous perfusion 1 month after RT was predicted by the locally accumulated biologically corrected dose at the end of RT (P<.0007). Regional portal venous perfusion measured during RT was a significant predictor for regional venous perfusion assessed 1 month after RT (P<.00001). Global hypovenous perfusion pre-RT was observed in 4 patients (3 patients with hepatocellular carcinoma and cirrhosis), 3 of whom had recovered from hypoperfusion, except in the highest dose regions, post-RT. In addition, 3 patients who had normal perfusion pre-RT had marked hypervenous perfusion or reperfusion in low-dose regions post-RT. Conclusions: This study suggests that MR-based volumetric hepatic perfusion imaging may be a biomarker for spatial distribution of liver function, which could aid in individualizing therapy, particularly for patients at risk for liver injury after RT.

  20. Cardiac Magnetic Resonance Imaging Findings in 20-year Survivors of Mediastinal Radiotherapy for Hodgkin's Disease

    SciTech Connect (OSTI)

    Machann, Wolfram; Beer, Meinrad [Department of Radiology, University of Wuerzburg (Germany); Breunig, Margret; Stoerk, Stefan; Angermann, Christiane [Department of Cardiology, University of Wuerzburg (Germany); Seufert, Ines; Schwab, Franz; Koelbl, Oliver; Flentje, Michael [Department of Radiation Oncology, University of Wuerzburg (Germany); Vordermark, Dirk, E-mail: dirk.vordermark@medizin.uni-halle.d [Department of Radiation Oncology, University of Wuerzburg (Germany); Department of Radiation Oncology, Martin Luther University Halle-Wittenberg (Germany)

    2011-03-15T23:59:59.000Z

    Purpose: The recognition of the true prevalence of cardiac toxicity after mediastinal radiotherapy requires very long follow-up and a precise diagnostic procedure. Cardiac magnetic resonance imaging (MRI) permits excellent quantification of cardiac function and identification of localized myocardial defects and has now been applied to a group of 20-year Hodgkin's disease survivors. Methods and materials: Of 143 patients treated with anterior mediastinal radiotherapy (cobalt-60, median prescribed dose 40 Gy) for Hodgkin's disease between 1978 and 1985, all 53 survivors were invited for cardiac MRI. Of those, 36 patients (68%) presented for MRI, and in 31 patients (58%) MRI could be performed 20-28 years (median, 24) after radiotherapy. The following sequences were acquired on a 1.5-T MRI: transversal T1-weighted TSE and T2-weighted half-fourier acquisition single-shot turbo-spin-echo sequences, a steady-state free precession (SSFP) cine sequence in the short heart axis and in the four-chamber view, SSFP perfusion sequences under rest and adenosine stress, and a SSFP inversion recovery sequence for late enhancement. The MRI findings were correlated with previously reconstructed doses to cardiac structures. Results: Clinical characteristics and reconstructed doses were not significantly different between survivors undergoing and not undergoing MRI. Pathologic findings were reduced left ventricular function (ejection fraction <55%) in 7 (23%) patients, hemodynamically relevant valvular dysfunction in 13 (42%), late myocardial enhancement in 9 (29%), and any perfusion deficit in 21 (68%). An association of regional pathologic changes and reconstructed dose to cardiac structures could not be established. Conclusions: In 20-year survivors of Hodgkin's disease, cardiac MRI detects pathologic findings in approximately 70% of patients. Cardiac MRI has a potential role in cardiac imaging of Hodgkin's disease patients after mediastinal radiotherapy.

  1. Discrete magic angle turning system, apparatus, and process for in situ magnetic resonance spectroscopy and imaging

    DOE Patents [OSTI]

    Hu, Jian Zhi (Richland, WA); Sears, Jr., Jesse A. (Kennewick, WA); Hoyt, David W. (Richland, WA); Wind, Robert A. (Kennewick, WA)

    2009-05-19T23:59:59.000Z

    Described are a "Discrete Magic Angle Turning" (DMAT) system, devices, and processes that combine advantages of both magic angle turning (MAT) and magic angle hopping (MAH) suitable, e.g., for in situ magnetic resonance spectroscopy and/or imaging. In an exemplary system, device, and process, samples are rotated in a clockwise direction followed by an anticlockwise direction of exactly the same amount. Rotation proceeds through an angle that is typically greater than about 240 degrees but less than or equal to about 360 degrees at constant speed for a time applicable to the evolution dimension. Back and forth rotation can be synchronized and repeated with a special radio frequency (RF) pulse sequence to produce an isotropic-anisotropic shift 2D correlation spectrum. The design permits tubes to be inserted into the sample container without introducing plumbing interferences, further allowing control over such conditions as temperature, pressure, flow conditions, and feed compositions, thus permitting true in-situ investigations to be carried out.

  2. Radiation-Induced Alterations in Mouse Brain Development Characterized by Magnetic Resonance Imaging

    SciTech Connect (OSTI)

    Gazdzinski, Lisa M.; Cormier, Kyle [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada)] [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Lu, Fred G. [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto (Canada)] [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto (Canada); Lerch, Jason P. [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada) [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada); Wong, C. Shun [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto (Canada) [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada); Department of Radiation Oncology, University of Toronto, Toronto (Canada); Nieman, Brian J., E-mail: bjnieman@phenogenomics.ca [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada)

    2012-12-01T23:59:59.000Z

    Purpose: The purpose of this study was to identify regions of altered development in the mouse brain after cranial irradiation using longitudinal magnetic resonance imaging (MRI). Methods and Materials: Female C57Bl/6 mice received a whole-brain radiation dose of 7 Gy at an infant-equivalent age of 2.5 weeks. MRI was performed before irradiation and at 3 time points following irradiation. Deformation-based morphometry was used to quantify volume and growth rate changes following irradiation. Results: Widespread developmental deficits were observed in both white and gray matter regions following irradiation. Most of the affected brain regions suffered an initial volume deficit followed by growth at a normal rate, remaining smaller in irradiated brains compared with controls at all time points examined. The one exception was the olfactory bulb, which in addition to an early volume deficit, grew at a slower rate thereafter, resulting in a progressive volume deficit relative to controls. Immunohistochemical assessment revealed demyelination in white matter and loss of neural progenitor cells in the subgranular zone of the dentate gyrus and subventricular zone. Conclusions: MRI can detect regional differences in neuroanatomy and brain growth after whole-brain irradiation in the developing mouse. Developmental deficits in neuroanatomy persist, or even progress, and may serve as useful markers of late effects in mouse models. The high-throughput evaluation of brain development enabled by these methods may allow testing of strategies to mitigate late effects after pediatric cranial irradiation.

  3. Advanced slow-magic angle spinning probe for magnetic resonance imaging and spectroscopy

    DOE Patents [OSTI]

    Wind, Robert A.; Hu, Jian Zhi; Minard, Kevin R.; Rommereim, Donald N.

    2006-01-24T23:59:59.000Z

    The present invention relates to a probe and processes useful for magnetic resonance imaging and spectroscopy instruments. More particularly, the invention relates to a MR probe and processes for obtaining resolution enhancements of fluid objects, including live specimens, using an ultra-slow (magic angle) spinning (MAS) of the specimen combined with a modified phase-corrected magic angle turning (PHORMAT) pulse sequence. Proton NMR spectra were measured of the torso and the top part of the belly of a female BALBc mouse in a 2T field, while spinning the animal at a speed of 1.5 Hz. Results show that even in this relatively low field with PHORMAT, an isotropic spectrum is obtained with line widths that are a factor 4.6 smaller than those obtained in a stationary mouse. Resolution of 1H NMR metabolite spectra are thus significantly enhanced. Results indicate that PHORMAT has the potential to significantly increase the utility of 1H NMR spectroscopy for in vivo biochemical, biomedical and/or medical applications involving large-sized biological objects such as mice, rats and even humans within a hospital setting. For small-sized objects, including biological objects, such as excised tissues, organs, live bacterial cells, and biofilms, use of PASS at a spinning rate of 30 Hz and above is preferred.

  4. Magnetic Resonance Imaging at Princeton, UofV, and UNH | U.S...

    Office of Science (SC) Website

    supported by: NIH, NASA Impactbenefit to spin-off field: Static & dynamic imaging of lungs, heart, and possibly the brain, possible imaging of astronauts 'Hyperpolarized gas...

  5. DERIVATION OF THE MAGNETIC FIELD IN A CORONAL MASS EJECTION CORE VIA MULTI-FREQUENCY RADIO IMAGING

    SciTech Connect (OSTI)

    Tun, Samuel D. [The Naval Research Laboratory, Washington, DC 20375 (United States)] [The Naval Research Laboratory, Washington, DC 20375 (United States); Vourlidas, A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)] [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2013-04-01T23:59:59.000Z

    The magnetic field within the core of a coronal mass ejection (CME) on 2010 August 14 is derived from analysis of multi-wavelength radio imaging data. This CME's core was found to be the source of a moving type IV radio burst, whose emission is here determined to arise from the gyrosynchrotron process. The CME core's true trajectory, electron density, and line-of-sight depth are derived from stereoscopic observations, constraining these parameters in the radio emission models. We find that the CME carries a substantial amount of mildly relativistic electrons (E < 100 keV) in a strong magnetic field (B < 15 G), and that the spectra at lower heights are preferentially suppressed at lower frequencies through absorption from thermal electrons. We discuss the results in light of previous moving type IV burst studies, and outline a plan for the eventual use of radio methods for CME magnetic field diagnostics.

  6. Revisiting the Rigidly Rotating Magnetosphere model for $\\sigma$ Ori E - II. Magnetic Doppler imaging, arbitrary field RRM, and light variability

    E-Print Network [OSTI]

    Oksala, M E; Krticka, J; Townsend, R H D; Wade, G A; Prvak, M; Mikulasek, Z; Silvester, J; Owocki, S P

    2015-01-01T23:59:59.000Z

    The initial success of the Rigidly Rotating Magnetosphere (RRM) model application to the B2Vp star sigma OriE by Townsend, Owocki & Groote (2005) triggered a renewed era of observational monitoring of this archetypal object. We utilize high-resolution spectropolarimetry and the magnetic Doppler imaging (MDI) technique to simultaneously determine the magnetic configuration, which is predominately dipolar, with a polar strength Bd = 7.3-7.8 kG and a smaller non-axisymmetric quadrupolar contribution, as well as the surface distribution of abundance of He, Fe, C, and Si. We describe a revised RRM model that now accepts an arbitrary surface magnetic field configuration, with the field topology from the MDI models used as input. The resulting synthetic Ha emission and broadband photometric observations generally agree with observations, however, several features are poorly fit. To explore the possibility of a photospheric contribution to the observed photometric variability, the MDI abundance maps were used to ...

  7. Magnetic resonance visualization of conductive structures by sequence-triggered direct currents and spin-echo phase imaging

    SciTech Connect (OSTI)

    Eibofner, Frank; Wojtczyk, Hanne; Graf, Hansjörg, E-mail: hansjoerg.graf@med.uni-tuebingen.de, E-mail: drGraf@t-online.de [Section on Experimental Radiology, University Hospital Tübingen, Tübingen D-72076 (Germany)] [Section on Experimental Radiology, University Hospital Tübingen, Tübingen D-72076 (Germany); Clasen, Stephan [Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen D-72076 (Germany)] [Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen D-72076 (Germany)

    2014-06-15T23:59:59.000Z

    Purpose: Instrument visualization in interventional magnetic resonance imaging (MRI) is commonly performed via susceptibility artifacts. Unfortunately, this approach suffers from limited conspicuity in inhomogeneous tissue and disturbed spatial encoding. Also, susceptibility artifacts are controllable only by sequence parameters. This work presents the basics of a new visualization method overcoming such problems by applying sequence-triggered direct current (DC) pulses in spin-echo (SE) imaging. SE phase images allow for background free current path localization. Methods: Application of a sequence-triggered DC pulse in SE imaging, e.g., during a time period between radiofrequency excitation and refocusing, results in transient field inhomogeneities. Dependent on the additional z-magnetic field from the DC, a phase offset results despite the refocusing pulse. False spatial encoding is avoided by DC application during periods when read-out or slice-encoding gradients are inactive. A water phantom containing a brass conductor (water equivalent susceptibility) and a titanium needle (serving as susceptibility source) was used to demonstrate the feasibility. Artifact dependence on current strength and orientation was examined. Results: Without DC, the brass conductor was only visible due to its water displacement. The titanium needle showed typical susceptibility artifacts. Applying triggered DC pulses, the phase offset of spins near the conductor appeared. Because SE phase images are homogenous also in regions of persistent field inhomogeneities, the position of the conductor could be determined with high reliability. Artifact characteristic could be easily controlled by amperage leaving sequence parameters unchanged. For an angle of 30° between current and static field visualization was still possible. Conclusions: SE phase images display the position of a conductor carrying pulsed DC free from artifacts caused by persistent field inhomogeneities. Magnitude and phase images are acquired simultaneously under the same conditions without the use of extra measurement time. The presented technique offers many advantages for precise instrument localization in interventional MRI.

  8. Magnetic Imaging of Micrometer and Nanometer-size Magnetic Structures and Their Flux-Pinning Effects on Superconducting Thin Films

    E-Print Network [OSTI]

    Ozmetin, Ali E.

    2010-07-14T23:59:59.000Z

    to various ferromagnetic structures. These magnetic structures include: (i) alternating iron-brass shims of 275 mu m period, (ii) an array of 4 mu m wide Co stripes with smaller period (9 mu m), (iii) a square array of 50nm diameter, high aspect ratio (5...

  9. Magnetic force microscopy method and apparatus to detect and image currents in integrated circuits

    DOE Patents [OSTI]

    Campbell, Ann. N. (13170-B Central SE #188, Albuquerque, NM 87123); Anderson, Richard E. (2800 Tennessee NE, Albuquerque, NM 87110); Cole, Jr., Edward I. (2116 White Cloud NE, Albuquerque, NM 87112)

    1995-01-01T23:59:59.000Z

    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.

  10. Nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOE Patents [OSTI]

    Fukushima, Eiichi (Los Alamos, NM); Roeder, Stephen B. W. (La Mesa, CA); Assink, Roger A. (Albuquerque, NM); Gibson, Atholl A. V. (Bryan, TX)

    1986-01-01T23:59:59.000Z

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio-frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  11. HST.583 Functional Magnetic Resonance Imaging: Data Acquisition and Analysis, Fall 2002

    E-Print Network [OSTI]

    Gollub, Randy L.

    Provides information relevant to the conduct and interpretation of human brain mapping studies. Provides in-depth coverage of the physics of image formation, mechanisms of image contrast, and the physiological basis for ...

  12. HST.583 Functional Magnetic Resonance Imaging: Data Acquisition and Analysis, Fall 2004

    E-Print Network [OSTI]

    Gollub, Randy L.

    Provides information relevant to the conduct and interpretation of human brain mapping studies. Provides in-depth coverage of the physics of image formation, mechanisms of image contrast, and the physiological basis for ...

  13. Imaging and Spectroscopic Diagnostics on the Formation of Two Magnetic Flux Ropes Revealed by SDO/AIA and IRIS

    E-Print Network [OSTI]

    Cheng, X; Fang, C

    2015-01-01T23:59:59.000Z

    Helical magnetic flux rope (MFR) is a fundamental structure of corona mass ejections (CMEs) and has been discovered recently to exist as a sigmoidal channel structure prior to its eruption in the extreme ultraviolet (EUV) high temperature passbands of the Atmospheric Imaging Assembly (AIA). However, when and where the MFR is built up are still elusive. In this paper, we investigate two MFRs (MFR1 and MFR2) in detail, whose eruptions produced two energetic solar flares and CMEs on 2014 April 18 and 2014 September 10, respectively. The AIA EUV images reveal that for a long time prior to their eruption, both MFR1 and MFR2 are under formation, which is probably through magnetic reconnection between two groups of sheared arcades driven by the shearing and converging flows in the photosphere near the polarity inversion line. At the footpoints of the MFR1, the \\textit{Interface Region Imaging Spectrograph} Si IV, C II, and Mg II lines exhibit weak to moderate redshifts and a non-thermal broadening in the pre-flare p...

  14. Evaluating Swallowing Muscles Essential for Hyolaryngeal Elevation by Using Muscle Functional Magnetic Resonance Imaging

    SciTech Connect (OSTI)

    Pearson, William G., E-mail: bp1@bu.edu [Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts (United States); Hindson, David F. [Department of Radiology, Boston Medical Center, Boston, Massachusetts (United States)] [Department of Radiology, Boston Medical Center, Boston, Massachusetts (United States); Langmore, Susan E. [Department of Otolaryngology, Boston Medical Center, Boston, Massachusetts (United States) [Department of Otolaryngology, Boston Medical Center, Boston, Massachusetts (United States); Speech and Hearing Sciences, Boston University, Boston, Massachusetts (United States); Zumwalt, Ann C. [Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts (United States)] [Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts (United States)

    2013-03-01T23:59:59.000Z

    Purpose: Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercises thought to be specific to hyolaryngeal elevation. Methods and Materials: mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Results: Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Conclusions: Muscles of both the suprahyoid and the longitudinal pharyngeal muscle groups are active in swallowing, and both swallowing exercises effectively target muscles elevating the hyolaryngeal complex. mfMRI is useful in testing swallowing muscle function.

  15. Developing novel polymer architectures for applications In magnetic resonance imaging and self-assembly

    E-Print Network [OSTI]

    McCombs, Jessica R. (Jessica Rose)

    2013-01-01T23:59:59.000Z

    Macromolecular scaffolds for drug delivery, self-assembly, and imaging applications have attracted significant attention over the last several decades. As polymerization techniques become more sophisticated, it becomes ...

  16. Transmit field pattern control for high field magnetic resonance imaging with integrated RF current sources 

    E-Print Network [OSTI]

    Kurpad, Krishna Nagaraj

    2005-11-01T23:59:59.000Z

    The primary design criterion for RF transmit coils for MRI is uniform transverse magnetic (B1) field. Currently, most high frequency transmit coils are designed as periodic, symmetric structures that are resonant at the ...

  17. Method for nuclear magnetic resonance imaging using deuterum as a contrast agent

    DOE Patents [OSTI]

    Kehayias, Joseph J. (Chestnut Hill, MA); Joel, Darrel D. (Setauket, NY); Adams, William H. (Eastport, NY); Stein, Harry L. (Glen Head, NY)

    1990-01-01T23:59:59.000Z

    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.

  18. Coil performance evaluation based on electrodynamics : tools for hardware design and validation in magnetic resonance imaging

    E-Print Network [OSTI]

    Lattanzi, Riccardo

    2008-01-01T23:59:59.000Z

    Parallel MRI techniques allow acceleration of MR imaging beyond traditional speed limits. In parallel MRI, radiofrequency (RF) detector coil arrays are used to perform some degree of spatial encoding which complements ...

  19. A Survey of Prostate Segmentation Methodologies in Ultrasound, Magnetic Resonance and Computed Tomography Images

    E-Print Network [OSTI]

    Boyer, Edmond

    A Survey of Prostate Segmentation Methodologies in Ultrasound, Magnetic Resonance and Computed@gmail.com (Soumya Ghose), aoliver@eia.udg.edu (Arnau Oliver), marly@eia.udg.edu (Robert Mart´i), llado@eia.udg.edu (Xavier Llad´o), jordif@eia.udg.edu (Jordi Freixenet), jhimlimitra@yahoo.com (Jhimli Mitra), desire

  20. Fast and contrast-enhanced phase-sensitive magnetic resonance imaging

    E-Print Network [OSTI]

    Son, Jong Bum

    2009-05-15T23:59:59.000Z

    two signals if the resonance frequencies are close. For example, in MR mammography, it is difficult to separate silicone breast implants signals (4.0 ppm) from fat signals (3.5 ppm); (2) the signal dynamic range of images acquired using Dixon...

  1. An analysis of the PERL Magnetic Resonance Imaging theory and implementation

    E-Print Network [OSTI]

    Kremkus, Mark Christian

    2013-02-22T23:59:59.000Z

    The goal of PERL MRI in its most basic form is single shot imaging without the need to rapidly switch gradients to encode spatial information into the signal. PERL MRI incorporates the application of the PERL field into the standard spin echo...

  2. Highly Parallel Magnetic Resonance Imaging with a Fourth Gradient Channel for Compensation of RF Phase Patterns

    E-Print Network [OSTI]

    Bosshard, John 1983-

    2012-08-20T23:59:59.000Z

    70% increase in SNR [62]. The same group used an array of four arc shaped coils around a cylinder for microscopy for SENSE and GRAPPA accelerated imaging [63]. The greater field of view provided by an array of small coils was noted by Laistler et...

  3. Classification System for Identifying Women at Risk for Altered Partial Breast Irradiation Recommendations After Breast Magnetic Resonance Imaging

    SciTech Connect (OSTI)

    Kowalchik, Kristin V. [Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida (United States); Vallow, Laura A., E-mail: vallow.laura@mayo.edu [Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida (United States); McDonough, Michelle [Department of Radiology, Mayo Clinic, Jacksonville, Florida (United States); Thomas, Colleen S.; Heckman, Michael G. [Section of Biostatistics, Mayo Clinic, Jacksonville, Florida (United States); Peterson, Jennifer L. [Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida (United States); Adkisson, Cameron D. [Department of General Surgery, Mayo Clinic, Jacksonville, Florida (United States); Serago, Christopher [Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida (United States); McLaughlin, Sarah A. [Department of General Surgery, Mayo Clinic, Jacksonville, Florida (United States)

    2013-09-01T23:59:59.000Z

    Purpose: To study the utility of preoperative breast MRI for partial breast irradiation (PBI) patient selection, using multivariable analysis of significant risk factors to create a classification rule. Methods and Materials: Between 2002 and 2009, 712 women with newly diagnosed breast cancer underwent preoperative bilateral breast MRI at Mayo Clinic Florida. Of this cohort, 566 were retrospectively deemed eligible for PBI according to the National Surgical Adjuvant Breast and Bowel Project Protocol B-39 inclusion criteria using physical examination, mammogram, and/or ultrasound. Magnetic resonance images were then reviewed to determine their impact on patient eligibility. The patient and tumor characteristics were evaluated to determine risk factors for altered PBI eligibility after MRI and to create a classification rule. Results: Of the 566 patients initially eligible for PBI, 141 (25%) were found ineligible because of pathologically proven MRI findings. Magnetic resonance imaging detected additional ipsilateral breast cancer in 118 (21%). Of these, 62 (11%) had more extensive disease than originally noted before MRI, and 64 (11%) had multicentric disease. Contralateral breast cancer was detected in 28 (5%). Four characteristics were found to be significantly associated with PBI ineligibility after MRI on multivariable analysis: premenopausal status (P=.021), detection by palpation (P<.001), first-degree relative with a history of breast cancer (P=.033), and lobular histology (P=.002). Risk factors were assigned a score of 0-2. The risk of altered PBI eligibility from MRI based on number of risk factors was 0:18%; 1:22%; 2:42%; 3:65%. Conclusions: Preoperative bilateral breast MRI altered the PBI recommendations for 25% of women. Women who may undergo PBI should be considered for breast MRI, especially those with lobular histology or with 2 or more of the following risk factors: premenopausal, detection by palpation, and first-degree relative with a history of breast cancer.

  4. Assessment of Wall Shear Stress Changes in Arteries and Veins of Arteriovenous Polytetrafluoroethylene Grafts Using Magnetic Resonance Imaging

    SciTech Connect (OSTI)

    Misra, Sanjay, E-mail: Misra.sanjay@mayo.edu; Woodrum, David A. [Mayo Clinic, Department of Radiology (United States); Homburger, Jay [Medical College of Georgia, Department of Vascular Surgery (United States); Elkouri, Stephane [Centre Hospitalier de I'Universite de Montreal, Department of Vascular Surgery (Canada); Mandrekar, Jayawant N. [Mayo Clinic, Division of Biostatistics (United States); Barocas, Victor [University of Minnesota, Department of Biomedical Engineering (United States); Glockner, James F. [Mayo Clinic, Department of Radiology (United States); Rajan, Dheeraj K. [Toronto General Hospital, University Health Network, Department of Medical Imaging, Division of Vascular and Interventional Radiology (Canada); Mukhopadhyay, Debabrata [Mayo Clinic, Department of Biochemistry and Molecular Biology (United States)

    2006-08-15T23:59:59.000Z

    The purpose of the study was to determine simultaneously the temporal changes in luminal vessel area, blood flow, and wall shear stress (WSS) in both the anastomosed artery (AA) and vein (AV) of arteriovenous polytetrafluoroethylene (PTFE) grafts. PTFE grafts were placed from the iliac artery to the ipsilateral iliac vein in 12 castrated juvenile male pigs. Contrast-enhanced magnetic resonance angiograpgy with cine phase-contrast magnetic resonance imaging was performed. Luminal vessel area, blood flow, and WSS in the aorta, AA, AV, and inferior vena cava were determined at 3 days (D3), 7 days (D7), and 14 days (D14) after graft placement. Elastin von Gieson staining of the AV was performed. The average WSS of the AA was highest at D3 and then decreased by D7 and D14. In contrast, the average WSS and intima-to-media ratio of the AV increased from D3 to D7 and peaked by D14. Similarly, the average area of the AA was highest by D7 and began to approximate the control artery by D14. The average area of the AV had decreased to its lowest by D7. High blood flows through the AA causes a decrease in average WSS and increase in the average luminal vessel area, whereas at the AV, the average WSS and intima-to-media ratio both increase while the average luminal vessel area decreases.

  5. Prediction of the reversibility of the ultrasound-induced blood-brain barrier opening using passive cavitation detection with magnetic resonance imaging

    E-Print Network [OSTI]

    Konofagou, Elisa E.

    cavitation detection with magnetic resonance imaging validation Tao Sun1 , Gesthimani Samiotaki1 and Elisa E (diameters: 1-2, 4-5, or 6-8 m). A 10-MHz passive cavitation detector was used to acquire cavitation signals that the stable cavitation dose increased with the number of days required for closing while it reached a plateau

  6. Intensity inhomogeneity correction for magnetic resonance imaging of human brain at 7T

    SciTech Connect (OSTI)

    Uwano, Ikuko; Yamashita, Fumio; Higuchi, Satomi; Ito, Kenji; Sasaki, Makoto [Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Yahaba, Iwate 028-3694 (Japan)] [Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Yahaba, Iwate 028-3694 (Japan); Kudo, Kohsuke, E-mail: kkudo@huhp.hokudai.ac.jp; Goodwin, Jonathan; Harada, Taisuke [Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Yahaba, Iwate 028-3694, Japan and Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Hokkaido 060-8648 (Japan)] [Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Yahaba, Iwate 028-3694, Japan and Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Hokkaido 060-8648 (Japan); Ogawa, Akira [Department of Neurosurgery, Iwate Medical University, Morioka, Iwate 020-8505 (Japan)] [Department of Neurosurgery, Iwate Medical University, Morioka, Iwate 020-8505 (Japan)

    2014-02-15T23:59:59.000Z

    Purpose: To evaluate the performance and efficacy for intensity inhomogeneity correction of various sequences of the human brain in 7T MRI using the extended version of the unified segmentation algorithm. Materials: Ten healthy volunteers were scanned with four different sequences (2D spin echo [SE], 3D fast SE, 2D fast spoiled gradient echo, and 3D time-of-flight) by using a 7T MRI system. Intensity inhomogeneity correction was performed using the “New Segment” module in SPM8 with four different values (120, 90, 60, and 30 mm) of full width at half maximum (FWHM) in Gaussian smoothness. The uniformity in signals in the entire white matter was evaluated using the coefficient of variation (CV); mean signal intensities between the subcortical and deep white matter were compared, and contrast between subcortical white matter and gray matter was measured. The length of the lenticulostriate (LSA) was measured on maximum intensity projection (MIP) images in the original and corrected images. Results: In all sequences, the CV decreased as the FWHM value decreased. The differences of mean signal intensities between subcortical and deep white matter also decreased with smaller FWHM values. The contrast between white and gray matter was maintained at all FWHM values. LSA length was significantly greater in corrected MIP than in the original MIP images. Conclusions: Intensity inhomogeneity in 7T MRI can be successfully corrected using SPM8 for various scan sequences.

  7. Currents driven by electron cyclotron waves

    SciTech Connect (OSTI)

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

    1981-07-01T23:59:59.000Z

    Certain aspects of the generation of steady-state currents by electron cyclotron waves are explored. A numerical solution of the Fokker-Planck equation is used to verify the theory of Fisch and Boozer and to extend their results into the nonlinear regime. Relativistic effects on the current generated are discussed. Applications to steady-state tokamak reactors are considered.

  8. CURRENTS DRIVEN BY ELECTRON CYCLOTRON WAVES

    E-Print Network [OSTI]

    Karney, Charles

    [2], which also exploits, among other things, the rela- tive infrequency with which the superthermal

  9. Lensless Imaging of Magnetic Nanostructures by X-ray Spectro-Holography

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  10. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  11. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

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  12. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  13. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  14. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  15. Minimally Invasive Magnetic Resonance Imaging-Guided Free-Hand Aspiration of Symptomatic Nerve Route Compressing Lumbosacral Cysts Using a 1.0-Tesla Open Magnetic Resonance Imaging System

    SciTech Connect (OSTI)

    Bucourt, Maximilian de, E-mail: mdb@charite.de; Streitparth, Florian, E-mail: florian.streitparth@charite.de; Collettini, Federico [Charite-University Medicine, Department of Radiology (Germany); Guettler, Felix [Jena University, Department of Radiology (Germany); Rathke, Hendrik; Lorenz, Britta; Rump, Jens; Hamm, Bernd [Charite-University Medicine, Department of Radiology (Germany); Teichgraeber, U. K. [Jena University, Department of Radiology (Germany)

    2012-02-15T23:59:59.000Z

    Purpose: To evaluate the feasibility of minimally invasive magnetic resonance imaging (MRI)-guided free-hand aspiration of symptomatic nerve route compressing lumbosacral cysts in a 1.0-Tesla (T) open MRI system using a tailored interactive sequence. Materials and Methods: Eleven patients with MRI-evident symptomatic cysts in the lumbosacral region and possible nerve route compressing character were referred to a 1.0-T open MRI system. For MRI interventional cyst aspiration, an interactive sequence was used, allowing for near real-time position validation of the needle in any desired three-dimensional plane. Results: Seven of 11 cysts in the lumbosacral region were successfully aspirated (average 10.1 mm [SD {+-} 1.9]). After successful cyst aspiration, each patient reported speedy relief of initial symptoms. Average cyst size was 9.6 mm ({+-}2.6 mm). Four cysts (8.8 {+-} 3.8 mm) could not be aspirated. Conclusion: Open MRI systems with tailored interactive sequences have great potential for cyst aspiration in the lumbosacral region. The authors perceive major advantages of the MR-guided cyst aspiration in its minimally invasive character compared to direct and open surgical options along with consecutive less trauma, less stress, and also less side-effects for the patient.

  16. A Signal-Inducing Bone Cement for Magnetic Resonance Imaging-Guided Spinal Surgery Based on Hydroxyapatite and Polymethylmethacrylate

    SciTech Connect (OSTI)

    Wichlas, Florian, E-mail: florian.wichlas@charite.de; Seebauer, Christian J.; Schilling, Rene [University Charite, Center for Musculoskeletal Surgery (Germany); Rump, Jens [University Charite, Department of Radiology (Germany); Chopra, Sascha S. [University Charite, Center for Musculoskeletal Surgery (Germany); Walter, Thula; Teichgraeber, Ulf K. M. [University Charite, Department of Radiology (Germany); Bail, Hermann J. [University Charite, Center for Musculoskeletal Surgery (Germany)

    2012-06-15T23:59:59.000Z

    The aim of this study was to develop a signal-inducing bone cement for magnetic resonance imaging (MRI)-guided cementoplasty of the spine. This MRI cement would allow precise and controlled injection of cement into pathologic lesions of the bone. We mixed conventional polymethylmethacrylate bone cement (PMMA; 5 ml methylmethacrylate and 12 g polymethylmethacrylate) with hydroxyapatite (HA) bone substitute (2-4 ml) and a gadolinium-based contrast agent (CA; 0-60 {mu}l). The contrast-to-noise ratio (CNR) of different CA doses was measured in an open 1.0-Tesla scanner for fast T1W Turbo-Spin-Echo (TSE) and T1W TSE pulse sequences to determine the highest signal. We simulated MRI-guided cementoplasty in cadaveric spines. Compressive strength of the cements was tested. The highest CNR was (1) 87.3 (SD 2.9) in fast T1W TSE for cements with 4 {mu}l CA/ml HA (4 ml) and (2) 60.8 (SD 2.4) in T1W TSE for cements with 1 {mu}l CA/ml HA (4 ml). MRI-guided cementoplasty in cadaveric spine was feasible. Compressive strength decreased with increasing amounts of HA from 46.7 MPa (2 ml HA) to 28.0 MPa (4 ml HA). An MRI-compatible cement based on PMMA, HA, and CA is feasible and clearly visible on MRI images. MRI-guided spinal cementoplasty using this cement would permit direct visualization of the cement, the pathologic process, and the anatomical surroundings.

  17. Magnetic dipole discharges. III. Instabilities

    SciTech Connect (OSTI)

    Stenzel, R. L.; Urrutia, J. M. [Department of Physics and Astronomy, University of California Los Angeles, California 90095-1547 (United States)] [Department of Physics and Astronomy, University of California Los Angeles, California 90095-1547 (United States); Ionita, C.; Schrittwieser, R. [Institute for Ion Physics and Applied Physics, University of Innsbruck A-6020 Innsbruck (Austria)] [Institute for Ion Physics and Applied Physics, University of Innsbruck A-6020 Innsbruck (Austria)

    2013-08-15T23:59:59.000Z

    Instabilities in a cross-field discharge around a permanent magnet have been investigated. The permanent magnet serves as a cold cathode and the chamber wall as an anode. The magnet is biased strongly negative and emits secondary electrons due to impact of energetic ions. The electrons outside the sheath are confined by the strong dipolar magnetic field and by the ion-rich sheath surrounding the magnet. The electron energy peaks in the equatorial plane where most ionization occurs and the ions are trapped in a negative potential well. The discharge mechanism is the same as that of cylindrical and planar magnetrons, but here extended to a 3-D cathode geometry using a single dipole magnet. While the basic properties of the discharge are presented in a companion paper, the present focus is on various observed instabilities. The first is an ion sheath instability which oscillates the plasma potential outside the sheath below the ion plasma frequency. It arises in ion-rich sheaths with low electron supply, which is the case for low secondary emission yields. Sheath oscillations modulate the discharge current creating oscillating magnetic fields. The second instability is current-driven ion sound turbulence due to counter-streaming electrons and ions. The fluctuations have a broad spectrum and short correlation lengths in all directions. The third type of fluctuations is spiky potential and current oscillations in high density discharges. These appear to be due to unstable emission properties of the magnetron cathode.

  18. Magnetic Resonance Imaging-Guided Osseous Biopsy in Children With Chronic Recurrent Multifocal Osteomyelitis

    SciTech Connect (OSTI)

    Fritz, Jan, E-mail: jfritz9@jhmi.edu [Johns Hopkins University School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science (United States); Tzaribachev, Nikolay [University Children's Hospital, Eberhard-Karls-University Tuebingen, Division of Pediatric Rheumatology (Germany); Thomas, Christoph [Eberhard-Karls-University Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Wehrmann, Manfred [Eberhard-Karls-University Tuebingen, Department of Pathology (Germany); Horger, Marius S. [Eberhard-Karls-University Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Carrino, John A. [Johns Hopkins University School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science (United States); Koenig, Claudius W.; Pereira, Philippe L. [Eberhard-Karls-University Tuebingen, Department of Diagnostic and Interventional Radiology (Germany)

    2012-02-15T23:59:59.000Z

    Purpose: To report the safety and diagnostic performance of magnetic resonance (MRI)-guided core biopsy of osseous lesions in children with chronic recurrent multifocal osteomyelitis (CRMO) that were visible on MRI but were occult on radiography and computed tomography (CT). Materials and Methods: A retrospective analysis of MRI-guided osseous biopsy performed in seven children (four girls and three boys; mean age 13 years (range 11 to 14) with CRMO was performed. Indication for using MRI guidance was visibility of lesions by MRI only. MRI-guided procedures were performed with 0.2-Tesla (Magnetom Concerto; Siemens, Erlangen, Germany; n = 5) or 1.5-T (Magnetom Espree; Siemens; n = 2) open MRI systems. Core needle biopsy was obtained using an MRI-compatible 4-mm drill system. Conscious sedation or general anesthesia was used. Parameters evaluated were lesion visibility, technical success, procedure time, complications and microbiology, cytology, and histopathology findings. Results: Seven of seven (100%) targeted lesions were successfully visualized and sampled. All obtained specimens were sufficient for histopathological analysis. Length of time of the procedures was 77 min (range 64 to 107). No complications occurred. Histopathology showed no evidence of malignancy, which was confirmed at mean follow-up of 50 months (range 28 to 78). Chronic nonspecific inflammation characteristic for CRMO was present in four of seven (58%) patients, and edema with no inflammatory cells was found in three of seven (42%) patients. There was no evidence of infection in any patient. Conclusion: MRI-guided osseous biopsy is a safe and accurate technique for the diagnosis of pediatric CRMO lesions that are visible on MRI only.

  19. " Rotating, In Plane Magnetization and Magneto-Optic Imaging of Cracks in Thick-Section Steel Under Stainless-Steel Cladding".

    SciTech Connect (OSTI)

    Gerald Fitzpatrick & Richard Skaugset

    2000-10-13T23:59:59.000Z

    The nondestructive inspection (NDI) of thick-section steel nuclear reactor pressure vessels (RPV'S) is rendered difficult by rough stainless steel cladding. Because the cladding condition is poorly known in most RPV's, an NDI technique that is unaffected by cladding roughness would be a major advance. Magneto-optic imaging is one such technique. The purpose of this project was to develop a novel method to induce rotating, in-plane magnetization, and to combine this capability with magneto-optic imaging to produce a self-contained inspection system. Imaging of cracks under thick cladding (0.250 inches) was demonstrated using a system capable, in principle, of performing robotic inspections, both inside & outside a typical boiling water reactor (BWR) RPV. This report, together publications listed, constitutes a comprehensive account of this work.

  20. Imaging

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  1. Imaging

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  2. Imaging

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  3. Improved nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOE Patents [OSTI]

    Fukushima, E.; Roeder, S.B.W.; Assink, R.A.; Gibson, A.A.V.

    1984-01-01T23:59:59.000Z

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  4. Imaging dirac-mass disorder from magnetic dopant-atoms in the ferromagnetic topological insulator Crx(Bi?.?Sb?.?)??xTe?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lee, Inhee [Brookhaven National Lab. (BNL), Upton, NY (United States); Kim, Chung Koo [Brookhaven National Lab. (BNL), Upton, NY (United States); Lee, Jinho [Brookhaven National Lab. (BNL), Upton, NY (United States); Seoul National Univ., Seoul (Korea); Billinge, Simon J. L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Columbia Univ., New York, NY (United States); Zhong, Ruidan D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., Stony Brook, NY (United States); Schneeloch, John A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., Stony Brook, NY (United States); Liu, Tiansheng S. [Brookhaven National Lab. (BNL), Upton, NY (United States); North Univ. of China, Shanxi (China); Valla, Tonica [Brookhaven National Lab. (BNL), Upton, NY (United States); Tranquada, John M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gu, Genda [Brookhaven National Lab. (BNL), Upton, NY (United States); Davis, J. C. Seamus [Brookhaven National Lab. (BNL), Upton, NY (United States); Cornell Univ., Ithaca, NY (United States); Univ. of St. Andrews, Fife (Scotland)

    2015-02-03T23:59:59.000Z

    To achieve and use the most exotic electronic phenomena predicted for the surface states of 3D topological insulators (TIs), it is necessary to open a “Dirac-mass gap” in their spectrum by breaking time-reversal symmetry. Use of magnetic dopant atoms to generate a ferromagnetic state is the most widely applied approach. However, it is unknown how the spatial arrangements of the magnetic dopant atoms influence the Dirac-mass gap at the atomic scale or, conversely, whether the ferromagnetic interactions between dopant atoms are influenced by the topological surface states. Here we image the locations of the magnetic (Cr) dopant atoms in the ferromagnetic TI Cr?.??(Bi?.?Sb?.?)?.??Te?. Simultaneous visualization of the Dirac-mass gap ?(r) reveals its intense disorder, which we demonstrate is directly related to fluctuations in n(r), the Cr atom areal density in the termination layer. We find the relationship of surface-state Fermi wavevectors to the anisotropic structure of ?(r) not inconsistent with predictions for surface ferromagnetism mediated by those states. Moreover, despite the intense Dirac-mass disorder, the anticipated relationship ?(r)?n(r) is confirmed throughout and exhibits an electron–dopant interaction energy J* = 145 meV·nm². These observations reveal how magnetic dopant atoms actually generate the TI mass gap locally and that, to achieve the novel physics expected of time-reversal symmetry breaking TI materials, control of the resulting Dirac-mass gap disorder will be essential.

  5. Imaging dirac-mass disorder from magnetic dopant-atoms in the ferromagnetic topological insulator Crx(Bi?.?Sb?.?)??xTe?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lee, Inhee; Kim, Chung Koo; Lee, Jinho; Billinge, Simon J. L.; Zhong, Ruidan D.; Schneeloch, John A.; Liu, Tiansheng S.; Valla, Tonica; Tranquada, John M.; Gu, Genda; et al

    2015-02-03T23:59:59.000Z

    To achieve and use the most exotic electronic phenomena predicted for the surface states of 3D topological insulators (TIs), it is necessary to open a “Dirac-mass gap” in their spectrum by breaking time-reversal symmetry. Use of magnetic dopant atoms to generate a ferromagnetic state is the most widely applied approach. However, it is unknown how the spatial arrangements of the magnetic dopant atoms influence the Dirac-mass gap at the atomic scale or, conversely, whether the ferromagnetic interactions between dopant atoms are influenced by the topological surface states. Here we image the locations of the magnetic (Cr) dopant atoms in themore »ferromagnetic TI Cr?.??(Bi?.?Sb?.?)?.??Te?. Simultaneous visualization of the Dirac-mass gap ?(r) reveals its intense disorder, which we demonstrate is directly related to fluctuations in n(r), the Cr atom areal density in the termination layer. We find the relationship of surface-state Fermi wavevectors to the anisotropic structure of ?(r) not inconsistent with predictions for surface ferromagnetism mediated by those states. Moreover, despite the intense Dirac-mass disorder, the anticipated relationship ?(r)?n(r) is confirmed throughout and exhibits an electron–dopant interaction energy J* = 145 meV·nm². These observations reveal how magnetic dopant atoms actually generate the TI mass gap locally and that, to achieve the novel physics expected of time-reversal symmetry breaking TI materials, control of the resulting Dirac-mass gap disorder will be essential.« less

  6. Modeling sickle cell vasoocculsion in the rat leg: Quantification of trapped sickle cells and correlation with sup 31 P metabolic and sup 1 H magnetic resonance imaging changes

    SciTech Connect (OSTI)

    Fabry, M.E.; Rajanayagam, V.; Fine, E.; Holland, S.; Gore, J.C.; Nagel, R.L.; Kaul, D.K. (Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY (USA))

    1989-05-01T23:59:59.000Z

    The authors have developed an animal model to elucidate the acute effects of perfusion abnormalities on muscle metabolism induced by different density-defined classes of erythrocytes isolated from sickle cell anemia patients. Technetium-99m ({sup 99m}Tc)-labeled, saline-washed normal (AA), homozygous sickle (SS), or high-density SS (SS4) erythrocytes were injected into the femoral artery of the rat and quantitative {sup 99m}Tc imaging, {sup 31}P magnetic resonance spectroscopy by surface coil at 2 teslas, and {sup 1}H magnetic resonance imaging at 0.15 tesla were performed. Between 5 and 25 {mu}l of SS4 cells was trapped in the microcirculation of the thigh. In contrast, fewer SS discocytes (SS2) or AA cells were trapped. After injection of SS4 cells an initial increase in inorganic phosphate was observed in the region of the thigh served by the femoral artery, intracellular pH decreased, and subsequently the proton relaxation time T{sub 1} reached a broad maximum at 18-28 hr. When T{sub 1} obtained at this time was plotted against the volume of cells trapped, an increase of T{sub 1} over the control value of 411 {plus minus} 48 msec was found that was proportional to the number of cells trapped. They conclude that the densest SS cells are most effective at producing vasoocclusion. The extent of the change detected by {sup 1}H magnetic resonance imaging is dependent on the amount of cells trapped in the microcirculation and the magnitude of the initial increase of inorganic phosphate.

  7. Performance of a static-anode/flat-panel x-ray fluoroscopy system in a diagnostic strength magnetic field: A truly hybrid x-ray/MR imaging system

    SciTech Connect (OSTI)

    Fahrig, R.; Wen, Z.; Ganguly, A.; DeCrescenzo, G.; Rowlands, J.A.; Stevens, G.M.; Saunders, R.F.; Pelc, N.J. [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Department of Radiology and Department of Physics, Stanford University, Stanford, California 94305 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States); Sunnybrook and Women's Health Sciences Center and Medical Biophysics, University of Toronto, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5 (Canada); GE Healthcare, Schenectady, Wisconsin (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States)

    2005-06-15T23:59:59.000Z

    Minimally invasive procedures are increasing in variety and frequency, facilitated by advances in imaging technology. Our hybrid imaging system (GE Apollo{sup TM} flat panel, custom Brand x-ray static anode x-ray tube, GE Lunar high-frequency power supply and 0.5 T Signa SP{sup TM}) provides both x-ray and MR imaging capability to guide complex procedures without requiring motion of the patient between two distant gantries. The performance of the x-ray tube in this closely integrated system was evaluated by modeling and measuring both the response of the filament to an externally applied field and the behavior of the electron beam for field strengths and geometries of interest. The performance of the detector was assessed by measuring the slanted-edge modulation transfer function (MTF) and when placed at zero field and at 0.5 T. Measured resonant frequencies of filaments can be approximated using a modified vibrating beam model, and were at frequencies well below the 25 kHz frequency of our generator for our filament geometry. The amplitude of vibration was not sufficient to cause shorting of the filament during operation within the magnetic field. A simple model of electrons in uniform electric and magnetic fields can be used to estimate the deflection of the electron beam on the anode for the fields of interest between 0.2 and 0.5 T. The MTF measured at the detector and the DQE showed no significant difference inside and outside of the magnetic field. With the proper modifications, an x-ray system can be fully integrated with a MR system, with minimal loss of image quality. Any x-ray tube can be assessed for compatibility when placed at a particular location within the field using the models. We have also concluded that a-Si electronics are robust against magnetic fields. Detailed knowledge of the x-ray system installation is required to provide estimates of system operation.

  8. Element-specific imaging of magnetic domains at 25 nm spatial resolution using soft x-ray microscopy

    E-Print Network [OSTI]

    Bayreuther, Günther

    magnetic transmission x-ray microscopy M-TXM . This was first demonstrated at the synchrotron facility BESSY I in Berlin.8­10 In this article experiments with M-TXM obtained at the XM-1 beamline

  9. Near-electrode imager

    DOE Patents [OSTI]

    Rathke, Jerome W. (Lockport, IL); Klingler, Robert J. (Westmont, IL); Woelk, Klaus (Wachtberg, DE); Gerald, II, Rex E. (Brookfield, IL)

    2000-01-01T23:59:59.000Z

    An apparatus, near-electrode imager, for employing nuclear magnetic resonance imaging to provide in situ measurements of electrochemical properties of a sample as a function of distance from a working electrode. The near-electrode imager uses the radio frequency field gradient within a cylindrical toroid cavity resonator to provide high-resolution nuclear magnetic resonance spectral information on electrolyte materials.

  10. Magnetic Stereoscopy

    E-Print Network [OSTI]

    Thomas Wiegelmann; Bernd Inhester

    2006-12-21T23:59:59.000Z

    The space mission STEREO will provide images from two viewpoints. An important aim of the STEREO mission is to get a 3D view of the solar corona. We develop a program for the stereoscopic reconstruction of 3D coronal loops from images taken with the two STEREO spacecraft. A pure geometric triangulation of coronal features leads to ambiguities because the dilute plasma emissions complicates the association of features in image 1 with features in image 2. As a consequence of these problems the stereoscopic reconstruction is not unique and multiple solutions occur. We demonstrate how these ambiguities can be resolved with the help of different coronal magnetic field models (potential, linear and non-linear force-free fields). The idea is that, due to the high conductivity in the coronal plasma, the emitting plasma outlines the magnetic field lines. Consequently the 3D coronal magnetic field provides a proxy for the stereoscopy which allows to eliminate inconsistent configurations. The combination of stereoscopy and magnetic modelling is more powerful than one of these tools alone. We test our method with the help of a model active region and plan to apply it to the solar case as soon as STEREO data become available.

  11. A 200-MHz fully-differential CMOS front-end with an on-chip inductor for magnetic resonance imaging

    E-Print Network [OSTI]

    Ayala, Julio Enqrique, II

    2007-04-25T23:59:59.000Z

    with an observed liquid sample. In [5], an implantable solenoidal microcoil is designed to be 5 used in NMR microspectroscopy experiments in a 2-Tesla magnet (85.13-MHz). The outer diameter of the coil was approximately 200 ?m and the length was 580 ?m. The coil... microspec- troscopy. Liquid samples were loaded into a fused silica capillary positioned 50 ?m above a 3.5-turn microcoil so that approximately 1 nL of the sample was present above the sensitive region of the microcoil. At 5.9-Tesla magnet (250-MHz), NMR...

  12. Prostate Postbrachytherapy Seed Distribution: Comparison of High-Resolution, Contrast-Enhanced, T1- and T2-Weighted Endorectal Magnetic Resonance Imaging Versus Computed Tomography: Initial Experience

    SciTech Connect (OSTI)

    Bloch, B. Nicolas [Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA (United States); Department of Radiology, General Hospital Vienna, Medical University Vienna, Vienna (Austria)], E-mail: nbloch@bidmc.harvard.edu; Lenkinski, Robert E. [Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA (United States); Helbich, Thomas H. [Department of Radiology, General Hospital Vienna, Medical University Vienna, Vienna (Austria); Ngo, Long [Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA (United States); Oismueller, Renee [Institute for Radio-Oncology, Danube Hospital, Vienna (Austria); Jaromi, Silvia; Kubin, Klaus [Department of Radiology, General Hospital Vienna, Medical University Vienna, Vienna (Austria); Hawliczek, Robert [Institute for Radio-Oncology, Danube Hospital, Vienna (Austria); Kaplan, Irving D. [Department of Radiation Oncology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA (United States); Rofsky, Neil M. [Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA (United States)

    2007-09-01T23:59:59.000Z

    Purpose: To compare contrast-enhanced, T1-weighted, three-dimensional magnetic resonance imaging (CEMR) and T2-weighted magnetic resonance imaging (T2MR) with computed tomography (CT) for prostate brachytherapy seed location for dosimetric calculations. Methods and Materials: Postbrachytherapy prostate MRI was performed on a 1.5 Tesla unit with combined surface and endorectal coils in 13 patients. Both CEMR and T2MR used a section thickness of 3 mm. Spiral CT used a section thickness of 5 mm with a pitch factor of 1.5. All images were obtained in the transverse plane. Two readers using CT and MR imaging assessed brachytherapy seed distribution independently. The dependency of data read by both readers for a specific subject was assessed with a linear mixed effects model. Results: The mean percentage ({+-} standard deviation) values of the readers for seed detection and location are presented. Of 1205 implanted seeds, CEMR, T2MR, and CT detected 91.5% {+-} 4.8%, 78.5% {+-} 8.5%, and 96.1% {+-} 2.3%, respectively, with 11.8% {+-} 4.5%, 8.5% {+-} 3.5%, 1.9% {+-} 1.0% extracapsular, respectively. Assignment to periprostatic structures was not possible with CT. Periprostatic seed assignments for CEMR and T2MR, respectively, were as follows: neurovascular bundle, 3.5% {+-} 1.6% and 2.1% {+-} 0.9%; seminal vesicles, 0.9% {+-} 1.8% and 0.3% {+-} 0.7%; periurethral, 7.1% {+-} 3.3% and 5.8% {+-} 2.9%; penile bulb, 0.6% {+-} 0.8% and 0.3% {+-} 0.6%; Denonvillier's Fascia/rectal wall, 0.5% {+-} 0.6% and 0%; and urinary bladder, 0.1% {+-} 0.3% and 0%. Data dependency analysis showed statistical significance for the type of imaging but not for reader identification. Conclusion: Both enumeration and localization of implanted seeds are readily accomplished with CEMR. Calculations with MRI dosimetry do not require CT data. Dose determinations to specific extracapsular sites can be obtained with MRI but not with CT.

  13. NMR (nuclear magnetic resonance) imaging for detecting binder/plasticizers in green-state structural ceramics. [SiC, Al/sub 2/O/sub 3/, and Si/sub 3/N/sub 4/

    SciTech Connect (OSTI)

    Ellingson, W.A.; Ackerman, J.L.; Gronemeyer, S.; Garrido, L.

    1987-06-01T23:59:59.000Z

    We have explored both a small-bore (<10 cm) experimental imaging system as well as a state-of-the-art medical imaging system relative to detection of the soft-solid (wax-like) binders used in ceramics. The ability to detect binders was evaluated on a 1.5-T medical MRI imager (Siemens Magnetom) using T/sub 1/-weighted imaging techniques and a 10-cm eye coil standard with the system. The ability to detect binders was also studied with a modified small-bore coil Technicare Facility using special rf and gradient coils. The initial results show that a medical system may not be able to detect binders unless elevated temperatures are used, whereas the experimental small-bore system shows the distribution quite well. In addition, higher magnetic field strength should be better for ceramics, since proton signal strength increases rapidly with the magnetic field strength. 11 refs., 9 figs., 3 tabs.

  14. Abstract--This study presents a system designed to assist the surgeon during interventional procedures performed by Magnetic Resonance Imaging (MRI). In order to reach the target during guidance in a double obliquity trajectory, this

    E-Print Network [OSTI]

    Boyer, Edmond

    on the instrument are detected [4]. Two commercial solutions have recently appeared on the market: a robotic system of ionizing radiations, Magnetic Resonance Imaging is a well adapted modality for interventional practice. MRI stiff and short, enabling the use of passive detection and/or optical localisation. Passive tracking

  15. Real-Time Color-Flow Magnetic ResonanceImaging of Congenital Heart Disease E. De La Pena-Almaguer, K. S. Nayak, M. Terashima, P.C. Yang,

    E-Print Network [OSTI]

    Southern California, University of

    Real-Time Color-Flow Magnetic ResonanceImaging of Congenital Heart Disease E. De La Pena used for the diagnosis of congenital heart disease (CHD), although it has limitations. Conventional MRI flow pulse sequence.A low flip- angle water selective spectral-spatial excitation is followed

  16. Magnetic Resonance Imaging of Acute Reperfused Myocardial Infarction: Intraindividual Comparison of ECIII-60 and Gd-DTPA in a Swine Model

    SciTech Connect (OSTI)

    Jin Jiyang; Teng Gaojun [Zhongda Hospital of Southeast University, Department of Radiology (China); Feng Yi; Wu Yanping [Zhongda Hospital of Southeast University, Department of Cardiology (China); Jin Qindi [Zhongda Hospital of Southeast University, Department of Radiology (China); Wang Yu [Zhongda Hospital of Southeast University, Department of Cardiology (China); Wang Zhen [Zhongda Hospital of Southeast University, Department of Anaesthesiology (China); Lu Qin [Zhongda Hospital of Southeast University, Department of Radiology (China); Jiang Yibo [Zhongda Hospital of Southeast University, Department of Cardiology (China); Wang Shengqi; Chen Feng [Zhongda Hospital of Southeast University, Department of Radiology (China); Marchal, Guy; Ni Yicheng [University Hospitals, University of Leuven, Department of Radiology (Belgium)], E-mail: yicheng.ni@med.kuleuven.ac.be

    2007-04-15T23:59:59.000Z

    Purpose. To compare a necrosis-avid contrast agent (NACA) bis-Gd-DTPA-pamoic acid derivative (ECIII-60) after intracoronary delivery with an extracellular agent Gd-DTPA after intravenous injection on magnetic resonance imaging (MRI) in a swine model of acute reperfused myocardial infarction (MI). Methods. Eight pigs underwent 90 min of transcatheter coronary balloon occlusion and 60 min of reperfusion. After intravenous injection of Gd-DTPA at a dose of 0.2 mmol/kg, all pigs were scanned with T1-weighted MRI until the delayed enhancement of MI disappeared. Then they were intracoronarily infused with ECIII-60 at 0.0025 mmol/kg and imaged for 5 hr. Signal intensity, infarct-over-normal contrast ratio and relative infarct size were quantified, compared, and correlated with the results of postmortem MRI and triphenyltetrazolium chloride (TTC) histochemical staining. Results. A contrast ratio over 3.0 was induced by both Gd-DTPA and ECIII-60. However, while the delayed enhancement with Gd-DTPA virtually vanished in 1 hr, ECIII-60 at an 80x smaller dose depicted the MI accurately over 5 hr as proven by ex vivo MRI and TTC staining. Conclusion. Both Gd-DTPA and ECIII-60 strongly enhanced acute MI. Comparing with fading contrast in a narrow time window with intravenous Gd-DTPA, intracoronary ECIII-60 persistently demarcated the acute MI, indicating a potential method for postprocedural assessment of myocardial viability after coronary interventions.

  17. Stability Properties of Magnetic Tower Jets

    E-Print Network [OSTI]

    Masanori Nakamura; Hui Li; Shengtai Li

    2006-08-31T23:59:59.000Z

    Stability properties of ``magnetic tower'' jets propagating in the gravitationally stratified background have been examined by performing three-dimensional magnetohydrodynamic simulations. The current-carrying, Poynting flux-dominated magnetic tower jet, which possesses a highly wound helical magnetic field, is subject to the current-driven instability (CDI). We find that, under general physical conditions including small perturbations in the initial background profiles, the propagating magnetic tower jets develop the non-axisymmetric, $m=1$ kink mode of the CDI. The kink mode grows on the local Alfv\\'en crossing time scale. In addition, two types of kink modes appear in the system. At the central region where external thermal pressure confinement is strong, only the internal kink mode is excited and will grow. A large distance away from the central region where the external thermal pressure becomes low, the external kink mode is observed. As a result, the exterior of magnetic tower jets will be deformed into a large-scale wiggled structure. We also discuss extensively the different physical processes that contribute to the overall stability properties of the magnetic tower jets. Specifically, when the jet propagates in an initially unperturbed background, we find that they can survive the kink mode beyond the point predicted by the well-known Kruskal-Shafranov (K-S) criterion. The stabilization in this case comes mainly from the dynamical relaxation of magnetic twists during the propagation of magnetic towers; the magnetic pitch is reduced and the corresponding K-S critical wavelength becomes longer as the tower jet proceeds. Furthermore, we show that the pressure-driven and Kelvin-Helmholtz instabilities do not occur in the magnetic tower jets.

  18. Correlated Biofilm Imaging, Transport and Metabolism Measurements...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

  19. Image 2006 DESY A Beamline Simulation

    E-Print Network [OSTI]

    Gollin, George

    precise #12;Image © 2006 DESY A Zero Schematic BPM BPM BPM BPM BPM Yellow Magnet Kicker Corrector Magnet Spectrometer Magnet 1 2 3 4 5 BPM: Beam Position Monitor Yellow Magnet: Not part of experiment, suppose · BPM resolution · Time step · Yellow Magnet field strength · Kicker field strength · Corrector Magnet

  20. Use of T2-weighted magnetic resonance imaging of the optic nerve sheath to detect raised intracranial pressure

    E-Print Network [OSTI]

    Geeraerts, Thomas; Newcombe, Virginia F J; Coles, Jonathan P; Abate, Maria Giulia; Perkes, Iain E; Hutchinson, Peter J A; Outtrim, Jo G; Chatfield, Dot A; Menon, David K

    2008-09-11T23:59:59.000Z

    is accurate at measuring ONSD [27,28] and has been proposed to detect raised ICP in idiopathic hydrocephalus and to diagnose shunt malfunction [12,14,29,30]. On T2-weighted sequences, water (and CSF) exhibits a high signal (white). Fat and grey matter appear... as light grey, and white matter as dark grey. The perioptic CSF is surrounded by orbital fat. Contrast between CSF and orbital fat can be improved with fat suppression, increasing the image resolution for the ONSD measurement [12,13]. We have con- firmed...

  1. Journal of Magnetism and Magnetic Materials 286 (2005) 324328 Light-free magnetic resonance force microscopy for studies of

    E-Print Network [OSTI]

    Journal of Magnetism and Magnetic Materials 286 (2005) 324­328 Light-free magnetic resonance force for Physical Sciences, College Park, MD, USA Available online 4 November 2004 Abstract Magnetic resonance force microscopy is a scanned probe technique capable of three-dimensional magnetic resonance imaging. Its

  2. Nuclear magnetic resonance contrast agents

    DOE Patents [OSTI]

    Smith, P.H.; Brainard, J.R.; Jarvinen, G.D.; Ryan, R.R.

    1997-12-30T23:59:59.000Z

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC{sub 16}H{sub 14}N{sub 6}. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques. 10 figs.

  3. SU-E-T-136: Dosimetric Robustness of a Magnetic Resonance Imaging Guided Radiation Therapy (MR-IGRT) System

    SciTech Connect (OSTI)

    Rodriguez, V; Green, O; Wooten, H; Kashani, R; Mutic, S; Li, H [Washington University School of Medicine, St. Louis, MO (United States); Dempsey, J [View Ray Incorporated, Oakwood Village, OH (United States)

    2014-06-01T23:59:59.000Z

    Purpose: To test the radiation delivery robustness of the first MR-IGRT system using a commercial cylindrical diode array detector (ArcCHECK) and an ionization thimble chamber (Exradin A18). Methods: The MR-IGRT system is composed of three evenly spaced Co-60 sources on a rotating gantry located between two magnet halves. The collimator for each source consists of 30 doubly-focused leaf pairs that allow the system to deliver both conformal and intensity modulated (IMRT) treatment plans. The system's delivery robustness was tested over a span of 6 months from September 2013 through February 2014. This was achieved by repeatedly delivering 10 patient plans. These plans consisted of 2 conformal prostates, 2 IMRT prostates, 2 IMRT head and neck, 2 IMRT breast, 1 IMRT pancreas, and 1 IMRT bladder. The plans were generated with the system's treatment planning software. Once the plans were generated, quality assurance plans were created on a digital ArcCHECK dataset. The ArcCHECK used for testing was specially designed to be MR-compatible by moving the power supply outside of the magnetic field. The A18 ionization chamber was placed in a custom plastic plug insert in the center of the ArcCHECK. Gamma analysis was used with the ArcCHECK for relative dose evaluating both 3%/3mm and 2%/2mm. Absolute point dose was compared between ion chamber measurement and treatment plan. Results: The ArcCHECK passing rate remained constant over the 6 month period. The average passing rate for 3%/3mm and 2%/2mm analysis was 98.6% ± 0.7 and 88.8% ± 2.9, respectively. The ion chamber measurements showed little variation with an average percent difference between planned dose verses measured dose of 0.9% ± 0.7. Conclusion: Minimal differences were noted in the delivery of the 10 patient plans. Over a period that included acceptance testing, commissioning, and clinical deliveries, the MR-IGRT system remained consistent in radiation delivery.

  4. DEEP RADIO CONTINUUM IMAGING OF THE DWARF IRREGULAR GALAXY IC 10: TRACING STAR FORMATION AND MAGNETIC FIELDS

    SciTech Connect (OSTI)

    Heesen, V.; Brinks, E. [Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Rau, U.; Rupen, M. P. [NRAO, P.V.D. Science Operations Center, National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM 87801 (United States); Hunter, D. A. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)

    2011-09-20T23:59:59.000Z

    We exploit the vastly increased sensitivity of the Expanded Very Large Array to study the radio continuum and polarization properties of the post-starburst, dwarf irregular galaxy IC 10 at 6 cm, at a linear resolution of {approx}50 pc. We find close agreement between radio continuum and H{alpha} emission, from the brightest H II regions to the weaker emission in the disk. A quantitative analysis shows a strictly linear correlation, where the thermal component contributes 50% to the total radio emission, the remainder being due to a non-thermal component with a surprisingly steep radio spectral index of between -0.7 and -1.0 suggesting substantial radiation losses of the cosmic-ray electrons. We confirm and clearly resolve polarized emission at the 10%-20% level associated with a non-thermal superbubble, where the ordered magnetic field is possibly enhanced due to the compression of the expanding bubble. A fraction of the cosmic-ray electrons has likely escaped because the measured radio emission is a factor of three lower than what is suggested by the H{alpha}-inferred star formation rate.

  5. Cerebral edema induced in mice by a convulsive dose of soman. Evaluation through diffusion-weighted magnetic resonance imaging and histology

    SciTech Connect (OSTI)

    Testylier, Guy [Centre de Recherches du Service Sante des Armees, Departement de Toxicologie, BP87, F-38702 La Tronche cedex (France)]. E-mail: guytestylier@crssa.net; Lahrech, Hana [Inserm, UMR-S 836-Grenoble Institut des Neurosciences, Grenoble, F-38043 (France); Universite Joseph Fourier, Grenoble, F-38043 (France); Montigon, Olivier [Inserm, UMR-S 836-Grenoble Institut des Neurosciences, Grenoble, F-38043 (France); Universite Joseph Fourier, Grenoble, F-38043 (France); Foquin, Annie [Centre de Recherches du Service Sante des Armees, Departement de Toxicologie, BP87, F-38702 La Tronche cedex (France); Delacour, Claire [Centre de Recherches du Service Sante des Armees, Departement de Toxicologie, BP87, F-38702 La Tronche cedex (France); Bernabe, Denis [Centre de Recherches du Service Sante des Armees, Departement de Toxicologie, BP87, F-38702 La Tronche cedex (France); Segebarth, Christoph [Inserm, UMR-S 836-Grenoble Institut des Neurosciences, Grenoble, F-38043 (France); Universite Joseph Fourier, Grenoble, F-38043 (France); Dorandeu, Frederic [Centre de Recherches du Service Sante des Armees, Departement de Toxicologie, BP87, F-38702 La Tronche cedex (France); Carpentier, Pierre [Centre de Recherches du Service Sante des Armees, Departement de Toxicologie, BP87, F-38702 La Tronche cedex (France)

    2007-04-15T23:59:59.000Z

    Purpose: In the present study, diffusion-weighted magnetic resonance imaging (DW-MRI) and histology were used to assess cerebral edema and lesions in mice intoxicated by a convulsive dose of soman, an organophosphate compound acting as an irreversible cholinesterase inhibitor. Methods: Three hours and 24 h after the intoxication with soman (172 {mu}g/kg), the mice were anesthetized with an isoflurane/N{sub 2}O mixture and their brain examined with DW-MRI. After the imaging sessions, the mice were sacrificed for histological analysis of their brain. Results: A decrease in the apparent diffusion coefficient (ADC) was detected as soon as 3 h after the intoxication and was found strongly enhanced at 24 h. A correlation was obtained between the ADC change and the severity of the overall brain damage (edema and cellular degeneration): the more severe the damage, the stronger the ADC drop. Anesthesia was shown to interrupt soman-induced seizures and to attenuate edema and cell change in certain sensitive brain areas. Finally, brain water content was assessed using the traditional dry/wet weight method. A significant increase of brain water was observed following the intoxication. Conclusions: The ADC decrease observed in the present study suggests that brain edema in soman poisoning is mainly intracellular and cytotoxic. Since entry of water into Brain was also evidenced, this type of edema is certainly mixed with others (vasogenic, hydrostatic, osmotic). The present study confirms the potential of DW-MRI as a non-invasive tool for monitoring the acute neuropathological consequences (edema and neurodegeneration) of soman-induced seizures.

  6. angle lipomas magnetic: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of ambient magnetic field because it is almost insensitive to the downstream distribution of magnetic field and emitting electrons. We apply our method to a new radio image...

  7. assessing dynamic magnetic: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    0 Assessment of Carotid Flow Using Magnetic Resonance Imaging and Computational Fluid Dynamics) direct, model-independent velocity mapping using flow-encoded magnetic resonance...

  8. Use of Non-Invasive Phase Contrast Magnetic Resonance Imaging for Estimation of Atrial Septal Defect Size and Morphology: A Comparison with Transesophageal Echo

    SciTech Connect (OSTI)

    Piaw, Chin Sze; Kiam, Ong Tiong [Sarawak General Hospital, Department of Cardiology (Malaysia); Rapaee, Annuar [University of Malaysia Sarawak (Malaysia)], E-mail: rannuar@fmhs.unimas.myp; Khoon, Liew Chee; Bang, Liew Houng; Ling, Chan Wei [Sarawak General Hospital, Department of Cardiology (Malaysia); Samion, Hasri [National Heart Institute, Pediatric of Cardiology (Malaysia); Hian, Sim Kui [Sarawak General Hospital, Department of Cardiology (Malaysia)

    2006-04-15T23:59:59.000Z

    Background: Transesophageal echocardiography (TEE) is a trusted method of sizing atrial septal defect (ASD) prior to percutaneous closure but is invasive, uncomfortable, and may carry a small risk of morbidity and mortality. Magnetic resonance imaging (MRI) may be useful non-invasive alternative in such patients who refuse or are unable to tolerate TEE and may provide additional information on the shape of the A0SD. Purpose: To validate the accuracy of ASD sizing by MRI compared with TEE.Method: Twelve patients (mean age 30 years; range 11-60 years) scheduled for ASD closure underwent TEE, cine balanced fast field echo MRI (bFFE-MRI) in four-chamber and sagittal views and phase-contrast MRI (PC-MRI) with reconstruction using the two orthogonal planes of T2-weighted images as planning. The average of the three longest measurements for all imaging modalities was calculated for each patient. Results: Mean maximum ASD length on TEE was 18.8 {+-} 4.6 mm, mean length by bFFE-MRI was 20.0 {+-} 5.0 mm, and mean length by PC-MRI was 18.3 {+-} 3.6 mm. The TEE measurement was significantly correlated with the bFFE-MRI and PC-MRI measurements (Pearson r = 0.69, p = 0.02 and r = 0.59, p = 0.04, respectively). The mean difference between TEE and bFFE-MRI measurements was -1.2mm (95% CI: -3.7, 1.3) and between TEE and PC-MRI was 0.5 mm (95% CI: -1.9, 2.9). Bland-Altman analysis also determined general agreement between both MRI methods and TEE. The ASDs were egg-shaped in two cases, circular in 1 patient and oval in the remaining patients. Conclusion: ASD sizing by MRI using bFFE and phase-contrast protocols correlated well with TEE estimations. PC-MRI provided additional information on ASD shapes and proximity to adjacent structures.

  9. An Atlas-Based Electron Density Mapping Method for Magnetic Resonance Imaging (MRI)-Alone Treatment Planning and Adaptive MRI-Based Prostate Radiation Therapy

    SciTech Connect (OSTI)

    Dowling, Jason A., E-mail: jason.dowling@csiro.au [Australian e-Health Research Center, CSIRO ICT Commonwealth Scientific and Industrial Research Organisation Information and Communication Technologies Centre, Queensland (Australia); Lambert, Jonathan [Calvary Mater Newcastle Hospital, New South Wales (Australia); University of Newcastle, New South Wales (Australia); Parker, Joel [Calvary Mater Newcastle Hospital, New South Wales (Australia); Salvado, Olivier; Fripp, Jurgen [Australian e-Health Research Center, CSIRO ICT Commonwealth Scientific and Industrial Research Organisation Information and Communication Technologies Centre, Queensland (Australia); Capp, Anne; Wratten, Chris; Denham, James W.; Greer, Peter B. [Calvary Mater Newcastle Hospital, New South Wales (Australia); University of Newcastle, New South Wales (Australia)

    2012-05-01T23:59:59.000Z

    Purpose: Prostate radiation therapy dose planning directly on magnetic resonance imaging (MRI) scans would reduce costs and uncertainties due to multimodality image registration. Adaptive planning using a combined MRI-linear accelerator approach will also require dose calculations to be performed using MRI data. The aim of this work was to develop an atlas-based method to map realistic electron densities to MRI scans for dose calculations and digitally reconstructed radiograph (DRR) generation. Methods and Materials: Whole-pelvis MRI and CT scan data were collected from 39 prostate patients. Scans from 2 patients showed significantly different anatomy from that of the remaining patient population, and these patients were excluded. A whole-pelvis MRI atlas was generated based on the manually delineated MRI scans. In addition, a conjugate electron-density atlas was generated from the coregistered computed tomography (CT)-MRI scans. Pseudo-CT scans for each patient were automatically generated by global and nonrigid registration of the MRI atlas to the patient MRI scan, followed by application of the same transformations to the electron-density atlas. Comparisons were made between organ segmentations by using the Dice similarity coefficient (DSC) and point dose calculations for 26 patients on planning CT and pseudo-CT scans. Results: The agreement between pseudo-CT and planning CT was quantified by differences in the point dose at isocenter and distance to agreement in corresponding voxels. Dose differences were found to be less than 2%. Chi-squared values indicated that the planning CT and pseudo-CT dose distributions were equivalent. No significant differences (p > 0.9) were found between CT and pseudo-CT Hounsfield units for organs of interest. Mean {+-} standard deviation DSC scores for the atlas-based segmentation of the pelvic bones were 0.79 {+-} 0.12, 0.70 {+-} 0.14 for the prostate, 0.64 {+-} 0.16 for the bladder, and 0.63 {+-} 0.16 for the rectum. Conclusions: The electron-density atlas method provides the ability to automatically define organs and map realistic electron densities to MRI scans for radiotherapy dose planning and DRR generation. This method provides the necessary tools for MRI-alone treatment planning and adaptive MRI-based prostate radiation therapy.

  10. Submerged electricity generation plane with marine current-driven motors

    DOE Patents [OSTI]

    Dehlsen, James G.P.; Dehlsen, James B.; Fleming, Alexander

    2014-07-01T23:59:59.000Z

    An underwater apparatus for generating electric power from ocean currents and deep water tides. A submersible platform including two or more power pods, each having a rotor with fixed-pitch blades, with drivetrains housed in pressure vessels that are connected by a transverse structure providing buoyancy, which can be a wing depressor, hydrofoil, truss, or faired tube. The platform is connected to anchors on the seafloor by forward mooring lines and a vertical mooring line that restricts the depth of the device in the water column. The platform operates using passive, rather than active, depth control. The wing depressor, along with rotor drag loads, ensures the platform seeks the desired operational current velocity. The rotors are directly coupled to a hydraulic pump that drives at least one constant-speed hydraulic-motor generator set and enables hydraulic braking. A fluidic bearing decouples non-torque rotor loads to the main shaft driving the hydraulic pumps.

  11. Magnetic Resonance Imaging of concrete

    E-Print Network [OSTI]

    Burgoyne, Chris

    velocity · Relates Elastic modulus to speed of sound Assumes Concrete heterogeneous Can be affected by steel Modulus related to speed of sound Strength of concrete related to modulus Location of flaws structure · In both cases procedure is destructive Systems to monitor concrete modulus · Ultra-sonic pulse

  12. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your HomeLatest News ReleasesDepartmentLending a Hand

  13. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your HomeLatest News ReleasesDepartmentLending a

  14. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 -ofLearning from1-1Administration

  15. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 -ofLearning from1-1AdministrationLensless

  16. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 -ofLearning

  17. On the Dynamics of Magnetic Fluids in Magnetic Resonance Padraig J. Cantillon-Murphy

    E-Print Network [OSTI]

    in Magnetic Resonance Imaging by Padraig J. Cantillon-Murphy B.E., Electrical and Electronic EngineeringOn the Dynamics of Magnetic Fluids in Magnetic Resonance Imaging by Padraig J. Cantillon-Murphy Submitted to the Department of Electrical Engineering and Computer Science in partial fulfillment

  18. ON THE STRUCTURE AND STABILITY OF MAGNETIC TOWER JETS

    SciTech Connect (OSTI)

    Huarte-Espinosa, M.; Frank, A.; Blackman, E. G. [Department of Physics and Astronomy, University of Rochester, 600 Wilson Boulevard, Rochester, NY 14627-0171 (United States); Ciardi, A. [LERMA, Universite Pierre et Marie Curie, Observatoire de Paris, F-92195 Meudon (France); Hartigan, P. [Department of Physics and Astronomy, Rice University, 6100 S. Main, Houston, TX 77521-1892 (United States); Lebedev, S. V.; Chittenden, J. P. [Blackett Laboratory, Imperial College London, SW7 2BW London (United Kingdom)

    2012-09-20T23:59:59.000Z

    Modern theoretical models of astrophysical jets combine accretion, rotation, and magnetic fields to launch and collimate supersonic flows from a central source. Near the source, magnetic field strengths must be large enough to collimate the jet requiring that the Poynting flux exceeds the kinetic energy flux. The extent to which the Poynting flux dominates kinetic energy flux at large distances from the engine distinguishes two classes of models. In magneto-centrifugal launch models, magnetic fields dominate only at scales {approx}< 100 engine radii, after which the jets become hydrodynamically dominated (HD). By contrast, in Poynting flux dominated (PFD) magnetic tower models, the field dominates even out to much larger scales. To compare the large distance propagation differences of these two paradigms, we perform three-dimensional ideal magnetohydrodynamic adaptive mesh refinement simulations of both HD and PFD stellar jets formed via the same energy flux. We also compare how thermal energy losses and rotation of the jet base affects the stability in these jets. For the conditions described, we show that PFD and HD exhibit observationally distinguishable features: PFD jets are lighter, slower, and less stable than HD jets. Unlike HD jets, PFD jets develop current-driven instabilities that are exacerbated as cooling and rotation increase, resulting in jets that are clumpier than those in the HD limit. Our PFD jet simulations also resemble the magnetic towers that have been recently created in laboratory astrophysical jet experiments.

  19. Technique Recovers Atomic Resolution in Spectrum Images | ornl...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in Spectrum Images April 08, 2015 Raw Fe L-shell spectrum image data, which indicate magnetic properties of the material, were acquired using scanning transmission electron...

  20. Treatment of Locally Advanced Vaginal Cancer With Radiochemotherapy and Magnetic Resonance Image-Guided Adaptive Brachytherapy: Dose-Volume Parameters and First Clinical Results

    SciTech Connect (OSTI)

    Dimopoulos, Johannes C.A. [Department of Radiation Oncology, Metropolitan Hospital, Athens (Greece); Schmid, Maximilian P., E-mail: maximilian.schmid@akhwien.at [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria); Fidarova, Elena; Berger, Daniel; Kirisits, Christian; Poetter, Richard [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria)

    2012-04-01T23:59:59.000Z

    Purpose: To investigate the clinical feasibility of magnetic resonance image-guided adaptive brachytherapy (IGABT) for patients with locally advanced vaginal cancer and to report treatment outcomes. Methods and Materials: Thirteen patients with vaginal cancer were treated with external beam radiotherapy (45-50.4 Gy) plus IGABT with or without chemotherapy. Distribution of International Federation of Gynecology and Obstetrics stages among patients were as follows: 4 patients had Stage II cancer, 5 patients had Stage III cancer, and 4 patients had Stage IV cancer. The concept of IGABT as developed for cervix cancer was transferred and adapted for vaginal cancer, with corresponding treatment planning and reporting. Doses were converted to the equivalent dose in 2 Gy, applying the linear quadratic model ({alpha}/{beta} = 10 Gy for tumor; {alpha}/{beta} = 3 for organs at risk). Endpoints studied were gross tumor volume (GTV), dose-volume parameters for high-risk clinical target volume (HRCTV), and organs at risk, local control (LC), adverse side effects, and survival. Results: The mean GTV ({+-} 1 standard deviation) at diagnosis was 45.3 ({+-}30) cm{sup 3}, and the mean GTV at brachytherapy was 10 ({+-}14) cm{sup 3}. The mean D90 for the HRCTV was 86 ({+-}13) Gy. The mean D2cc for bladder, urethra, rectum, and sigmoid colon were 80 ({+-}20) Gy, 76 ({+-}16) Gy, 70 ({+-}9) Gy, and 60 ({+-}9) Gy, respectively. After a median follow-up of 43 months (range, 19-87 months), one local recurrence and two distant metastases cases were observed. Actuarial LC and overall survival rates at 3 years were 92% and 85%. One patient with Stage IVA and 1 patient with Stage III disease experienced fistulas (one vesicovaginal, one rectovaginal), and 1 patient developed periurethral necrosis. Conclusions: The concept of IGABT, originally developed for treating cervix cancer, appears to be applicable to vaginal cancer treatment with only minor adaptations. Dose-volume parameters for HRCTV and organs at risk are in a comparable range. First clinical results indicate excellent LC. Further prospective multicenter studies are needed to establish this method and to confirm these results.

  1. A Small Scale Magnetic Particle Relaxometer

    E-Print Network [OSTI]

    El Ghamrawy, Ahmed

    2013-12-09T23:59:59.000Z

    Magnetic Particle Imaging (MPI) is a newly found imaging modality. It utilizes superparamagnetic materials as tracers in the blood stream to obtain very high resolutions. MPI promises to have high sensitivity, high spatial resolution...

  2. Efficient MR image reconstruction for compressed MR imaging Junzhou Huang

    E-Print Network [OSTI]

    Huang, Junzhou

    to be very powerful for the MR image reconstruction. First, we decompose the original problem into L1 and TV.V. All rights reserved. 1. Introduction Magnetic Resonance (MR) imaging has been widely used in medical. Computation became the bottleneck that prevented this good model (1) from being used in practical MR image

  3. Efficient MR Image Reconstruction for Compressed MR Imaging

    E-Print Network [OSTI]

    Huang, Junzhou

    demonstrate the superior performance of the proposed algorithm for com- pressed MR image reconstruction. 1 [1][2] show that it is possi- ble to accurately reconstruct the Magnetic Resonance (MR) images from for real MR images. Computation became the bottleneck that prevented this good model (1) from being used

  4. A linear helicon plasma device with controllable magnetic field gradient

    SciTech Connect (OSTI)

    Barada, Kshitish K.; Chattopadhyay, P. K.; Ghosh, J.; Kumar, Sunil; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2012-06-15T23:59:59.000Z

    Current free double layers (CFDLs) are localized potential structures having spatial dimensions - Debye lengths and potential drops of more than local electron temperature across them. CFDLs do not need a current for them to be sustained and hence they differ from the current driven double layers. Helicon antenna produced plasmas in an expanded chamber along with an expanding magnetic field have shown the existence of CFDL near the expansion region. A helicon plasma device has been designed, fabricated, and installed in the Institute for Plasma Research, India to study the role of maximum magnetic field gradient as well as its location with respect to the geometrical expansion region of the chamber in CFDL formation. The special feature of this machine consisting of two chambers of different radii is its capability of producing different magnetic field gradients near the physical boundary between the two chambers either by changing current in one particular coil in the direction opposite to that in other coils and/or by varying the position of this particular coil. Although, the machine is primarily designed for CFDL experiments, it is also capable of carrying out many basic plasma physics experiments such as wave propagation, wave coupling, and plasma instabilities in a varying magnetic field topology. In this paper, we will present the details of the machine construction, its specialties, and some preliminary results about the production and characterization of helicon plasma in this machine.

  5. COLLIMATION AND CONFINEMENT OF MAGNETIC JETS BY EXTERNAL MEDIA

    SciTech Connect (OSTI)

    Levinson, Amir [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)] [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Begelman, Mitchell C., E-mail: Levinson@wise.tau.ac.il, E-mail: mitch@jila.colorado.edu [JILA, University of Colorado and National Institute of Standards and Technology, 440 UCB, Boulder, CO 80309-0440 (United States)

    2013-02-20T23:59:59.000Z

    We study the collimation of a highly magnetized jet by a surrounding cocoon that forms as a result of the interaction of the jet with the external medium. We show that in regions where the jet is well confined by the cocoon, current-driven instabilities should develop over timescales shorter than the expansion time of the jet's head. We speculate that these instabilities would give rise to complete magnetic field destruction, whereby the jet undergoes a transition from high to low sigma above the collimation zone. Using this assumption, we construct a self-consistent model for the evolution of the jet-cocoon system in an ambient medium of arbitrary density profile. We apply the model to jet breakout in long gamma-ray bursts (GRBs) and show that the jet is highly collimated inside the envelope of the progenitor star and is likely to remain confined well after breakout. We speculate that this strong confinement may provide a channel for magnetic field conversion in GRB outflows, whereby the hot, low-sigma jet section thereby produced is the source of the photospheric emission observed in many bursts.

  6. Tumor Metabolism and Perfusion in Head and Neck Squamous Cell Carcinoma: Pretreatment Multimodality Imaging With {sup 1}H Magnetic Resonance Spectroscopy, Dynamic Contrast-Enhanced MRI, and [{sup 18}F]FDG-PET

    SciTech Connect (OSTI)

    Jansen, Jacobus F.A. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Radiology, Maastricht University Medical Center, Maastricht (Netherlands); Schoeder, Heiko [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Lee, Nancy Y. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Stambuk, Hilda E. [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Wang Ya [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Fury, Matthew G. [Department of Medical Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Patel, Senehal G. [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Pfister, David G. [Department of Medical Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Shah, Jatin P. [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Koutcher, Jason A. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Medical Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Shukla-Dave, Amita, E-mail: davea@mskcc.org [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2012-01-01T23:59:59.000Z

    Purpose: To correlate proton magnetic resonance spectroscopy ({sup 1}H-MRS), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and {sup 18}F-labeled fluorodeoxyglucose positron emission tomography ([{sup 18}F]FDG PET) of nodal metastases in patients with head and neck squamous cell carcinoma (HNSCC) for assessment of tumor biology. Additionally, pretreatment multimodality imaging was evaluated for its efficacy in predicting short-term response to treatment. Methods and Materials: Metastatic neck nodes were imaged with {sup 1}H-MRS, DCE-MRI, and [{sup 18}F]FDG PET in 16 patients with newly diagnosed HNSCC, before treatment. Short-term patient radiological response was evaluated at 3 to 4 months. Correlations among {sup 1}H-MRS (choline concentration relative to water [Cho/W]), DCE-MRI (volume transfer constant [K{sup trans}]; volume fraction of the extravascular extracellular space [v{sub e}]; and redistribution rate constant [k{sub ep}]), and [{sup 18}F]FDG PET (standard uptake value [SUV] and total lesion glycolysis [TLG]) were calculated using nonparametric Spearman rank correlation. To predict short-term responses, logistic regression analysis was performed. Results: A significant positive correlation was found between Cho/W and TLG ({rho} = 0.599; p = 0.031). Cho/W correlated negatively with heterogeneity measures of standard deviation std(v{sub e}) ({rho} = -0.691; p = 0.004) and std(k{sub ep}) ({rho} = -0.704; p = 0.003). Maximum SUV (SUVmax) values correlated strongly with MRI tumor volume ({rho} = 0.643; p = 0.007). Logistic regression indicated that std(K{sup trans}) and SUVmean were significant predictors of short-term response (p < 0.07). Conclusion: Pretreatment multimodality imaging using {sup 1}H-MRS, DCE-MRI, and [{sup 18}F]FDG PET is feasible in HNSCC patients with nodal metastases. Additionally, combined DCE-MRI and [{sup 18}F]FDG PET parameters were predictive of short-term response to treatment.

  7. Video Toroid Cavity Imager

    DOE Patents [OSTI]

    Gerald, Rex E. II; Sanchez, Jairo; Rathke, Jerome W.

    2004-08-10T23:59:59.000Z

    A video toroid cavity imager for in situ measurement of electrochemical properties of an electrolytic material sample includes a cylindrical toroid cavity resonator containing the sample and employs NMR and video imaging for providing high-resolution spectral and visual information of molecular characteristics of the sample on a real-time basis. A large magnetic field is applied to the sample under controlled temperature and pressure conditions to simultaneously provide NMR spectroscopy and video imaging capabilities for investigating electrochemical transformations of materials or the evolution of long-range molecular aggregation during cooling of hydrocarbon melts. The video toroid cavity imager includes a miniature commercial video camera with an adjustable lens, a modified compression coin cell imager with a fiat circular principal detector element, and a sample mounted on a transparent circular glass disk, and provides NMR information as well as a video image of a sample, such as a polymer film, with micrometer resolution.

  8. Pretreatment Endorectal Coil Magnetic Resonance Imaging Findings Predict Biochemical Tumor Control in Prostate Cancer Patients Treated With Combination Brachytherapy and External-Beam Radiotherapy

    SciTech Connect (OSTI)

    Riaz, Nadeem [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Afaq, Asim; Akin, Oguz [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Pei Xin; Kollmeier, Marisa A.; Cox, Brett [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Hricak, Hedvig [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Zelefsky, Michael J., E-mail: zelefskm@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2012-11-01T23:59:59.000Z

    Purpose: To investigate the utility of endorectal coil magenetic resonance imaging (eMRI) in predicting biochemical relapse in prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy. Methods and Materials: Between 2000 and 2008, 279 men with intermediate- or high-risk prostate cancer underwent eMRI of their prostate before receiving brachytherapy and supplemental intensity-modulated radiotherapy. Endorectal coil MRI was performed before treatment and retrospectively reviewed by two radiologists experienced in genitourinary MRI. Image-based variables, including tumor diameter, location, number of sextants involved, and the presence of extracapsular extension (ECE), were incorporated with other established clinical variables to predict biochemical control outcomes. The median follow-up was 49 months (range, 1-13 years). Results: The 5-year biochemical relapse-free survival for the cohort was 92%. Clinical findings predicting recurrence on univariate analysis included Gleason score (hazard ratio [HR] 3.6, p = 0.001), PSA (HR 1.04, p = 0.005), and National Comprehensive Cancer Network risk group (HR 4.1, p = 0.002). Clinical T stage and the use of androgen deprivation therapy were not correlated with biochemical failure. Imaging findings on univariate analysis associated with relapse included ECE on MRI (HR 3.79, p = 0.003), tumor size (HR 2.58, p = 0.04), and T stage (HR 1.71, p = 0.004). On multivariate analysis incorporating both clinical and imaging findings, only ECE on MRI and Gleason score were independent predictors of recurrence. Conclusions: Pretreatment eMRI findings predict for biochemical recurrence in intermediate- and high-risk prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy. Gleason score and the presence of ECE on MRI were the only significant predictors of biochemical relapse in this group of patients.

  9. Influence of Cobalt Nanoparticles' Incorporation on the Magnetic Properties of the Nickel Nanofibers: Cobalt-Doped Nickel Nanofibers Prepared by Electrospinning

    E-Print Network [OSTI]

    Kim, Bongsoo

    , magnetic refrigeration systems, and contrast enhancement in magnetic resonance imaging carriers for drugsInfluence of Cobalt Nanoparticles' Incorporation on the Magnetic Properties of the Nickel, 2009 Among the common ferromagnetic metals, cobalt has distinct magnetic properties, so incorporation

  10. Nonuniform radiation damage in permanent magnet quadrupoles

    SciTech Connect (OSTI)

    Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2014-08-15T23:59:59.000Z

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

  11. Argonne scientists discover new magnetic phase in iron-based...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    neutron diffraction image giving evidence for the new magnetic phase in iron-based superconductors discovered by Argonne scientists. It shows the scattering results from a sample...

  12. Design Features of a Planar Hybrid/Permanent Magnet Strong Focusing Undulator for Free Electron Laser (FEL) And Synchrotron Radiation (SR) Applications

    SciTech Connect (OSTI)

    Tatchyn, Roman; /SLAC

    2011-09-09T23:59:59.000Z

    Insertion devices for Angstrom-wavelength Free Electron Laser (FEL) amplifiers driven by multi-GeV electron beams generally require distributed focusing substantially stronger than their own natural focusing fields. Over the last several years a wide variety of focusing schemes and configurations have been proposed for undulators of this class, ranging from conventional current-driven quadrupoles external to the undulator magnets to permanent magnet (PM) lattices inserted into the insertion device gap. In this paper we present design studies of a flexible high-field hybrid/PM undulator with strong superimposed planar PM focusing proposed for a 1.5 Angstrom Linac Coherent Light Source (LCLS) driven by an electron beam with a 1 mm-mr normalized emittance. Attainable field parameters, tuning modes, and potential applications of the proposed structure are discussed.

  13. Magnetic Barcoded Hydrogel Microparticles for Multiplexed Detection

    E-Print Network [OSTI]

    Bong, Ki Wan

    Magnetic polymer particles have been used in a wide variety of applications ranging from targeting and separation to diagnostics and imaging. Current synthesis methods have limited these particles to spherical or deformations ...

  14. Magnetic Resonance Pulse Sequences for Fluorine-19

    E-Print Network [OSTI]

    Terry, Robin

    2014-07-11T23:59:59.000Z

    . Magnetic resonance imaging (MRI) has the ability to noninvasively track the transplanted cells to ensure they are in the desired destination. Unlike other MRI contrast agents, fluorine-19 has the ability to provide unambiguous cell tracking for two reasons...

  15. Magnetic Resonance Imaging-Based Target Volume Delineation in Radiation Therapy Treatment Planning for Brain Tumors Using Localized Region-Based Active Contour

    SciTech Connect (OSTI)

    Aslian, Hossein [Department of Medical Radiation, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Sadeghi, Mahdi [Agricultural, Medical and Industrial Research School, Karaj (Iran, Islamic Republic of); Mahdavi, Seied Rabie [Department of Medical Physics, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Babapour Mofrad, Farshid [Department of Medical Radiation, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Astarakee, Mahdi, E-mail: M-Astarakee@Engineer.com [Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Khaledi, Navid [Department of Medical Radiation, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Fadavi, Pedram [Department of Radiation Oncology, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2013-09-01T23:59:59.000Z

    Purpose: To evaluate the clinical application of a robust semiautomatic image segmentation method to determine the brain target volumes in radiation therapy treatment planning. Methods and Materials: A local robust region-based algorithm was used on MRI brain images to study the clinical target volume (CTV) of several patients. First, 3 oncologists delineated CTVs of 10 patients manually, and the process time for each patient was calculated. The averages of the oncologists’ contours were evaluated and considered as reference contours. Then, to determine the CTV through the semiautomatic method, a fourth oncologist who was blind to all manual contours selected 4-8 points around the edema and defined the initial contour. The time to obtain the final contour was calculated again for each patient. Manual and semiautomatic segmentation were compared using 3 different metric criteria: Dice coefficient, Hausdorff distance, and mean absolute distance. A comparison also was performed between volumes obtained from semiautomatic and manual methods. Results: Manual delineation processing time of tumors for each patient was dependent on its size and complexity and had a mean (±SD) of 12.33 ± 2.47 minutes, whereas it was 3.254 ± 1.7507 minutes for the semiautomatic method. Means of Dice coefficient, Hausdorff distance, and mean absolute distance between manual contours were 0.84 ± 0.02, 2.05 ± 0.66 cm, and 0.78 ± 0.15 cm, and they were 0.82 ± 0.03, 1.91 ± 0.65 cm, and 0.7 ± 0.22 cm between manual and semiautomatic contours, respectively. Moreover, the mean volume ratio (=semiautomatic/manual) calculated for all samples was 0.87. Conclusions: Given the deformability of this method, the results showed reasonable accuracy and similarity to the results of manual contouring by the oncologists. This study shows that the localized region-based algorithms can have great ability in determining the CTV and can be appropriate alternatives for manual approaches in brain cancer.

  16. Platinum dendritic nanoparticles with magnetic behavior

    SciTech Connect (OSTI)

    Li, Wenxian, E-mail: wl240@uowmail.edu.au [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia); Solar Energy Technologies, School of Computing, Engineering, and Mathematics, University of Western Sydney, Penrith NSW 2751 (Australia); Sun, Ziqi; Nevirkovets, Ivan P.; Dou, Shi-Xue [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia); Tian, Dongliang [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of the Ministry of Education, School of Chemistry and the Environment, Beihang University, Beijing 100191 (China)

    2014-07-21T23:59:59.000Z

    Magnetic nanoparticles have attracted increasing attention for biomedical applications in magnetic resonance imaging, high frequency magnetic field hyperthermia therapies, and magnetic-field-gradient-targeted drug delivery. In this study, three-dimensional (3D) platinum nanostructures with large surface area that features magnetic behavior have been demonstrated. The well-developed 3D nanodendrites consist of plentiful interconnected nano-arms ?4?nm in size. The magnetic behavior of the 3D dendritic Pt nanoparticles is contributed by the localization of surface electrons due to strongly bonded oxygen/Pluronic F127 and the local magnetic moment induced by oxygen vacancies on the neighboring Pt and O atoms. The magnetization of the nanoparticles exhibits a mixed paramagnetic and ferromagnetic state, originating from the core and surface, respectively. The 3D nanodendrite structure is suitable for surface modification and high amounts of drug loading if the transition temperature was enhanced to room temperature properly.

  17. High-Grade Glioma Radiation Therapy Target Volumes and Patterns of Failure Obtained From Magnetic Resonance Imaging and {sup 18}F-FDOPA Positron Emission Tomography Delineations From Multiple Observers

    SciTech Connect (OSTI)

    Kosztyla, Robert, E-mail: rkosztyla@bccancer.bc.ca [Department of Medical Physics, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Chan, Elisa K.; Hsu, Fred [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Wilson, Don [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Department of Functional Imaging, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Ma, Roy; Cheung, Arthur [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Zhang, Susan [Department of Medical Physics, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Department of Functional Imaging, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Moiseenko, Vitali [Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California (United States); Benard, Francois [Department of Functional Imaging, British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Nichol, Alan [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, British Columbia (Canada)

    2013-12-01T23:59:59.000Z

    Purpose: The objective of this study was to compare recurrent tumor locations after radiation therapy with pretreatment delineations of high-grade gliomas from magnetic resonance imaging (MRI) and 3,4-dihydroxy-6-[{sup 18}F]fluoro-L-phenylalanine ({sup 18}F-FDOPA) positron emission tomography (PET) using contours delineated by multiple observers. Methods and Materials: Nineteen patients with newly diagnosed high-grade gliomas underwent computed tomography (CT), gadolinium contrast-enhanced MRI, and {sup 18}F-FDOPA PET/CT. The image sets (CT, MRI, and PET/CT) were registered, and 5 observers contoured gross tumor volumes (GTVs) using MRI and PET. Consensus contours were obtained by simultaneous truth and performance level estimation (STAPLE). Interobserver variability was quantified by the percentage of volume overlap. Recurrent tumor locations after radiation therapy were contoured by each observer using CT or MRI. Consensus recurrence contours were obtained with STAPLE. Results: The mean interobserver volume overlap for PET GTVs (42% ± 22%) and MRI GTVs (41% ± 22%) was not significantly different (P=.67). The mean consensus volume was significantly larger for PET GTVs (58.6 ± 52.4 cm{sup 3}) than for MRI GTVs (30.8 ± 26.0 cm{sup 3}, P=.003). More than 95% of the consensus recurrence volume was within the 95% isodose surface for 11 of 12 (92%) cases with recurrent tumor imaging. Ten (91%) of these cases extended beyond the PET GTV, and 9 (82%) were contained within a 2-cm margin on the MRI GTV. One recurrence (8%) was located outside the 95% isodose surface. Conclusions: High-grade glioma contours obtained with {sup 18}F-FDOPA PET had similar interobserver agreement to volumes obtained with MRI. Although PET-based consensus target volumes were larger than MRI-based volumes, treatment planning using PET-based volumes may not have yielded better treatment outcomes, given that all but 1 recurrence extended beyond the PET GTV and most were contained by a 2-cm margin on the MRI GTV.

  18. Magnetic investigations

    SciTech Connect (OSTI)

    Bath, G.D.; Jahren, C.E.; Rosenbaum, J.G. [Geological Survey, Denver, CO (USA); Baldwin, M.J. [Fenix and Scisson, Inc., Mercury, NV (USA)

    1983-12-31T23:59:59.000Z

    Air and ground magnetic anomalies in the Climax stock area of the NTS help define the gross configuration of the stock and detailed configuration of magnetized rocks at the Boundary and Tippinip faults that border the stock. Magnetizations of geologic units were evaluated by measurements of magnetic properties of drill core, minimum estimates of magnetizations from ground magnetic anomalies for near surface rocks, and comparisons of measured anomalies with anomalies computed by a three-dimensional forward program. Alluvial deposits and most sedimentary rocks are nonmagnetic, but drill core measurements reveal large and irregular changes in magnetization for some quartzites and marbles. The magnetizations of quartz monzonite and granodiorite near the stock surface are weak, about 0.15 A/m, and increase at a rate of 0.00196 A/m/m to 1.55 A/m, at depths greater than 700 m (2300 ft). The volcanic rocks of the area are weakly magnetized. Aeromagnetic anomalies 850 m (2800 ft) above the stock are explained by a model consisting of five vertical prisms. Prisms 1, 2, and 3 represent the near surface outline of the stock, prism 4 is one of the models developed by Whitehill (1973), and prism 5 is modified from the model developed by Allingham and Zietz (1962). Most of the anomaly comes from unsampled and strongly-magnetized deep sources that could be either granite or metamorphosed sedimentary rocks. 48 refs., 23 figs., 3 tabs.

  19. Magnetic Field Safety Magnetic Field Safety

    E-Print Network [OSTI]

    McQuade, D. Tyler

    Magnetic Field Safety Training #12;Magnetic Field Safety Strong Magnetic Fields exist around energized magnets. High magnetic fields alone are a recognized hazard only for personnel with certain medical conditions such as pacemakers, magnetic implants, or embedded shrapnel. In addition, high magnetic

  20. Strange Magnetism

    E-Print Network [OSTI]

    Thomas R. Hemmert; Ulf-G. Meissner; Sven Steininger

    1998-11-09T23:59:59.000Z

    We present an analytic and parameter-free expression for the momentum dependence of the strange magnetic form factor of the nucleon and its corresponding radius which has been derived in Heavy Baryon Chiral Perturbation Theory. We also discuss a model-independent relation between the isoscalar magnetic and the strange magnetic form factors of the nucleon based on chiral symmetry and SU(3) only. These limites are used to derive bounds on the strange magnetic moment of the proton from the recent measurement by the SAMPLE collaboration.

  1. Development of integrated imaging techniques for investigating biomarkers in glioblastoma

    E-Print Network [OSTI]

    Kim, Heisoog

    2011-01-01T23:59:59.000Z

    Cancer is a diverse disease with many manifestations. Various imaging modalities including magnetic resonance imaging (MRI) and positron emission tomography (PET) have been used to study human cancer. In this study, we ...

  2. Simultaneous PET/fMRI for imaging neuroreceptor dynamics

    E-Print Network [OSTI]

    Sander, Christin Y. (Christin Yen-Ming)

    2014-01-01T23:59:59.000Z

    Whole-brain neuroimaging is a key technique for studying brain function and connectivity. Recent advances in combining two imaging modalities - magnetic resonance imaging (MRI) and positron emission tomography (PET) - into ...

  3. Superconductive imaging surface magnetometer

    DOE Patents [OSTI]

    Overton, Jr., William C. (Los Alamos, NM); van Hulsteyn, David B. (Santa Fe, NM); Flynn, Edward R. (Los Alamos, NM)

    1991-01-01T23:59:59.000Z

    An improved pick-up coil system for use with Superconducting Quantum Interference Device gradiometers and magnetometers involving the use of superconducting plates near conventional pick-up coil arrangements to provide imaging of nearby dipole sources and to deflect environmental magnetic noise away from the pick-up coils. This allows the practice of gradiometry and magnetometry in magnetically unshielded environments. One embodiment uses a hemispherically shaped superconducting plate with interior pick-up coils, allowing brain wave measurements to be made on human patients. another embodiment using flat superconducting plates could be used in non-destructive evaluation of materials.

  4. Magnetic shielding

    DOE Patents [OSTI]

    Kerns, J.A.; Stone, R.R.; Fabyan, J.

    1985-02-12T23:59:59.000Z

    A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.

  5. Magnetic nanotubes

    DOE Patents [OSTI]

    Matsui, Hiroshi (Glen Rock, NJ); Matsunaga, Tadashi (Tokyo, JP)

    2010-11-16T23:59:59.000Z

    A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.

  6. 128 IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 25, NO. 1, JANUARY 2006 Unwrapping of MR Phase Images Using a

    E-Print Network [OSTI]

    Koetter, Ralf

    128 IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 25, NO. 1, JANUARY 2006 Unwrapping of MR Phase of blood flow [1], [2]. Extracting the phase image from its measured complex MR image is nontrivial because, phase unwrapping. I. INTRODUCTION A. Background Magnetic resonance (MR) phase images often contain

  7. 106 IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 29, NO. 1, JANUARY 2010 Feature Based Nonrigid Brain MR Image Registration

    E-Print Network [OSTI]

    Chung, Albert C. S.

    106 IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 29, NO. 1, JANUARY 2010 Feature Based Nonrigid Brain MR Image Registration With Symmetric Alpha Stable Filters Shu Liao* and Albert C. S. Chung Abstract--A new feature based nonrigid image registration method for magnetic resonance (MR) brain images

  8. Real-time high-resolution X-ray imaging and nuclear magnetic resonance study of the hydration of pure and Na-doped C3A in the presence of sulfates

    SciTech Connect (OSTI)

    Kirchheim,, A. P.; Dal Molin, D.C.; Emwas, Abdul-Hamid; Provis, J.L.; Fischer, P.; Monteiro, P.J.M.

    2010-12-01T23:59:59.000Z

    This study details the differences in real-time hydration between pure tricalcium aluminate (cubic C{sub 3}A or 3CaO {center_dot} Al{sub 2}O{sub 3}) and Na-doped tricalcium aluminate (orthorhombic C{sub 3}A or Na{sub 2}Ca{sub 8}Al{sub 6}O{sub 18}), in aqueous solutions containing sulfate ions. Pure phases were synthesized in the laboratory to develop an independent benchmark for the reactions, meaning that their reactions during hydration in a simulated early age cement pore solution (saturated with respect to gypsum and lime) were able to be isolated. Because the rate of this reaction is extremely rapid, most microscopy methods are not adequate to study the early phases of the reactions in the early stages. Here, a high-resolution full-field soft X-ray imaging technique operating in the X-ray water window, combined with solution analysis by {sup 27}Al nuclear magnetic resonance (NMR) spectroscopy, was used to capture information regarding the mechanism of C{sub 3}A hydration during the early stages. There are differences in the hydration mechanism between the two types of C{sub 3}A, which are also dependent on the concentration of sulfate ions in the solution. The reactions with cubic C{sub 3}A (pure) seem to be more influenced by higher concentrations of sulfate ions, forming smaller ettringite needles at a slower pace than the orthorhombic C{sub 3}A (Na-doped) sample. The rate of release of aluminate species into the solution phase is also accelerated by Na doping.

  9. Magnets & Magnet Condensed Matter Science

    E-Print Network [OSTI]

    McQuade, D. Tyler

    18 No. 1 CONDENSED MATTER SCIENCE Technique development, graphene, magnetism & magnetic materials Pressure 9 Metal to Insulator Transition on the N=0 Landau Level in Graphene 10 Evidence for Fractional Quantum Hall States in Suspended Bilayer and Trilayer Graphene 11 Fractional Quantum Hall Effect

  10. Test Images

    E-Print Network [OSTI]

    Test Images. I hope to have a set of test images for the course soon. Some images are available now; some will have to wait until I can find another 100-200

  11. Low dimensional magnetism

    E-Print Network [OSTI]

    Kjall, Jonas Alexander

    2012-01-01T23:59:59.000Z

    Magnetism in Ultracold Gases 4 Magnetic phase diagram of aMagnetism . . . . . . . . . . . .1.3 Magnetism in condensedIntroduction 1 Brief introduction to magnetism 1.1 Classic

  12. Adjustable permanent magnet assembly for NMR and MRI

    DOE Patents [OSTI]

    Pines, Alexander; Paulsen, Jeffrey; Bouchard, Louis S; Blumich, Bernhard

    2013-10-29T23:59:59.000Z

    System and methods for designing and using single-sided magnet assemblies for magnetic resonance imaging (MRI) are disclosed. The single-sided magnet assemblies can include an array of permanent magnets disposed at selected positions. At least one of the permanent magnets can be configured to rotate about an axis of rotation in the range of at least +/-10 degrees and can include a magnetization having a vector component perpendicular to the axis of rotation. The single-sided magnet assemblies can further include a magnet frame that is configured to hold the permanent magnets in place while allowing the at least one of the permanent magnets to rotate about the axis of rotation.

  13. Image Analysis

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Recognition Image Analysis and Recognition Snapshot1498121slicesqResedison Fibers permeating imaged material (Courtesy: Bale, Loring, Perciano and Ushizima) Imagery coming from...

  14. Controlling Magnetism at the Nanoscale

    E-Print Network [OSTI]

    Wong, Jared

    2012-01-01T23:59:59.000Z

    Manipulation of Magnetism - External148 Conclusion A The Magnetism Cheat Sheet A.1 Magnetic157 A.2 Magnetism Unit Conversion

  15. Hyper-resistivity and electron thermal conductivity due to destroyed magnetic surfaces in axisymmetric plasma equilibria

    SciTech Connect (OSTI)

    Weening, R. H. [Department of Radiologic Sciences, Thomas Jefferson University, 901 Walnut Street, Philadelphia, Pennsylvania 19107-5233 (United States)

    2012-06-15T23:59:59.000Z

    In order to model the effects of small-scale current-driven magnetic fluctuations in a mean-field theoretical description of a large-scale plasma magnetic field B(x,t), a space and time dependent hyper-resistivity {Lambda}(x,t) can be incorporated into the Ohm's law for the parallel electric field E Dot-Operator B. Using Boozer coordinates, a theoretical method is presented that allows for a determination of the hyper-resistivity {Lambda}({psi}) functional dependence on the toroidal magnetic flux {psi} for arbitrary experimental steady-state Grad-Shafranov axisymmetric plasma equilibria, if values are given for the parallel plasma resistivity {eta}({psi}) and the local distribution of any auxiliary plasma current. Heat transport in regions of plasma magnetic surfaces destroyed by resistive tearing modes can then be modeled by an electron thermal conductivity k{sub e}({psi})=({epsilon}{sub 0}{sup 2}m{sub e}/e{sup 2}){Lambda}({psi}), where e and m{sub e} are the electron charge and mass, respectively, while {epsilon}{sub 0} is the permittivity of free space. An important result obtained for axisymmetric plasma equilibria is that the {psi}{psi}-component of the metric tensor of Boozer coordinates is given by the relation g{sup {psi}{psi}}({psi}){identical_to}{nabla}{psi} Dot-Operator {nabla}{psi}=[{mu}{sub 0}G({psi})][{mu}{sub 0}I({psi})]/{iota}({psi}), with {mu}{sub 0} the permeability of free space, G({psi}) the poloidal current outside a magnetic surface, I({psi}) the toroidal current inside a magnetic surface, and {iota}({psi}) the rotational transform.

  16. Neutrino magnetic moment in a magnetized plasma

    E-Print Network [OSTI]

    N. V. Mikheev; E. N. Narynskaya

    2010-11-08T23:59:59.000Z

    The contribution of a magnetized plasma to the neutrino magnetic moment is calculated. It is shown that only part of the additional neutrino energy in magnetized plasma connecting with its spin and magnetic field strength defines the neutrino magnetic moment. It is found that the presence of magnetized plasma does not lead to the considerable increase of the neutrino magnetic moment in contrast to the results presented in literature previously.

  17. Single echo acquisition magnetic resonance imaging

    E-Print Network [OSTI]

    McDougall, Mary Preston

    2006-04-12T23:59:59.000Z

    ) for comparison to quasi- static field pattern modeling .................................................................................................37 3.25 Coil pattern with the appropriate signal and noise calculation areas marked for SNR evaluation...

  18. Nanoscale magnetic resonance imaging C. L. Degena

    E-Print Network [OSTI]

    Leonardo, Degiorgi

    tobacco mosaic virus particles sitting on a nanometer-thick layer of ad- sorbed hydrocarbons. This result, which represents a 100 million- fold improvement in volume resolution over conventional MRI considerable effort, attempts to push the spatial resolution of conventional MRI into the realm of high

  19. Direct Imaging of Asymmetric Magnetization Reversal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisitingContract Management FermiDavidDiesel pricesDiesel28, 2007,Dirac

  20. Direct Imaging of Asymmetric Magnetization Reversal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign: PotentialFederal Financial Interventions

  1. Direct Imaging of Asymmetric Magnetization Reversal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign: PotentialFederal Financial InterventionsDirect

  2. Array combination for parallel imaging in Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Spence, Dan Kenrick

    2007-09-17T23:59:59.000Z

    ......................................103 Figure 51. Diagram of geometry used...........................................................................104 Figure 52. 64 element 8x8 grid array SNR map using 64 receivers. ............................105 Figure 53. 64 element 8x8 grid...-factor maps for point combined array......................................................117 Figure 63. SENSE reconstructions using point combined array...................................118 Figure 64. Grid array geometry used for simulation...

  3. Petroglyphs, Lighting, and Magnetism

    E-Print Network [OSTI]

    Walker, Merle F

    2007-01-01T23:59:59.000Z

    1950 Electricity and Magnetism: Theory and Applications.I Petroglyphs, Lightning, and Magnetism | Walker Figure 8.I Petroglyphs, Lightning, and Magnetism | Walker Figure IL

  4. Seeing the magnetic monopole through the mirror of topological surface states

    SciTech Connect (OSTI)

    Qi, Xiao-Liang; Li, Rundong; /Stanford U., Phys. Dept.; Zang, Jiadong; /Fudan U.; Zhang, Shou-Cheng; /Stanford U., Phys. Dept. /Fudan U.

    2010-03-25T23:59:59.000Z

    Existence of the magnetic monopole is compatible with the fundamental laws of nature, however, this illusive particle has yet to be detected experimentally. In this work, we show that an electric charge near the topological surface state induces an image magnetic monopole charge due to the topological magneto-electric effect. The magnetic field generated by the image magnetic monopole can be experimentally measured, and the inverse square law of the field dependence can be determined quantitatively. We propose that this effect can be used to experimentally realize a gas of quantum particles carrying fractional statistics, consisting of the bound states of the electric charge and the image magnetic monopole charge.

  5. Simulations of magnetic nanoparticle Brownian motion

    E-Print Network [OSTI]

    Daniel B Reeves; John B Weaver

    2014-03-25T23:59:59.000Z

    Magnetic nanoparticles are useful in many medical applications because they interact with biology on a cellular level thus allowing microenvironmental investigation. An enhanced understanding of the dynamics of magnetic particles may lead to advances in imaging directly in magnetic particle imaging (MPI) or through enhanced MRI contrast and is essential for nanoparticle sensing as in magnetic spectroscopy of Brownian motion (MSB). Moreover, therapeutic techniques like hyperthermia require information about particle dynamics for effective, safe, and reliable use in the clinic. To that end, we have developed and validated a stochastic dynamical model of rotating Brownian nanoparticles from a Langevin equation approach. With no field, the relaxation time toward equilibrium matches Einstein's model of Brownian motion. In a static field, the equilibrium magnetization agrees with the Langevin function. For high frequency or low amplitude driving fields, behavior characteristic of the linearized Debye approximation is reproduced. In a higher field regime where magnetic saturation occurs, the magnetization and its harmonics compare well with the effective field model. On another level, the model has been benchmarked against experimental results, successfully demonstrating that harmonics of the magnetization carry enough information to infer environmental parameters like viscosity and temperature.

  6. Magnetic Catalysis vs Magnetic Inhibition

    E-Print Network [OSTI]

    Kenji Fukushima; Yoshimasa Hidaka

    2012-09-06T23:59:59.000Z

    We discuss the fate of chiral symmetry in an extremely strong magnetic field B. We investigate not only quark fluctuations but also neutral meson effects. The former would enhance the chiral-symmetry breaking at finite B according to the Magnetic Catalysis, while the latter would suppress the chiral condensate once B exceeds the scale of the hadron structure. Using a chiral model we demonstrate how neutral mesons are subject to the dimensional reduction and the low dimensionality favors the chiral-symmetric phase. We point out that this effect, the Magnetic Inhibition, can be a feasible explanation for recent lattice-QCD data indicating the decreasing behavior of the chiral-restoration temperature with increasing B.

  7. Heat Loss Measurement Using Infrared Imaging

    E-Print Network [OSTI]

    Seeber, S. A.

    1983-01-01T23:59:59.000Z

    levels for objects seen in the CRT. (Radiance levels refer to the amount of infrared energy produced by an object.) The conversion of these radiance compari sons to temperatures and heat flows will be discussed below. Infrared images may be recorded... radiance level comparisons since colors may be associated with particular temperature ranges. Black and white images may be colorized during the inspection process. Alternatively, the black and white images may be stored on magnetic tape and color...

  8. Superconducting Magnet Division

    E-Print Network [OSTI]

    Superconducting Magnet Division DOE NP Program Review - July 06 1 Brookhaven Magnet Division - Nuclear Physics Program Support Activities Superconducting Magnet Program RHIC Operations Support Spin Summary Peter Wanderer, DOE review, July 25, 2006 Acting Head, Superconducting Magnet Division #12

  9. People Images

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    People Images People Images Several hundred of the 1700 U.S. scientists contributing to the LHC accelerator and experiments gathered in June 2008 in CERN's building 40 CE0252 Joel...

  10. Image alignment

    DOE Patents [OSTI]

    Dowell, Larry Jonathan

    2014-04-22T23:59:59.000Z

    Disclosed is a method and device for aligning at least two digital images. An embodiment may use frequency-domain transforms of small tiles created from each image to identify substantially similar, "distinguishing" features within each of the images, and then align the images together based on the location of the distinguishing features. To accomplish this, an embodiment may create equal sized tile sub-images for each image. A "key" for each tile may be created by performing a frequency-domain transform calculation on each tile. A information-distance difference between each possible pair of tiles on each image may be calculated to identify distinguishing features. From analysis of the information-distance differences of the pairs of tiles, a subset of tiles with high discrimination metrics in relation to other tiles may be located for each image. The subset of distinguishing tiles for each image may then be compared to locate tiles with substantially similar keys and/or information-distance metrics to other tiles of other images. Once similar tiles are located for each image, the images may be aligned in relation to the identified similar tiles.

  11. artery magnetic resonance: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Whole Brain Isotropic Arterial Spin Labeling Magnetic Resonance Imaging in a transgenic mouse...

  12. Magnetic Reconnection

    SciTech Connect (OSTI)

    Masaaki Yamada, Russell Kulsrud and Hantao Ji

    2009-09-17T23:59:59.000Z

    We review the fundamental physics of magnetic reconnection in laboratory and space plasmas, by discussing results from theory, numerical simulations, observations from space satellites, and the recent results from laboratory plasma experiments. After a brief review of the well-known early work, we discuss representative recent experimental and theoretical work and attempt to interpret the essence of significant modern findings. In the area of local reconnection physics, many significant findings have been made with regard to two- uid physics and are related to the cause of fast reconnection. Profiles of the neutral sheet, Hall currents, and the effects of guide field, collisions, and micro-turbulence are discussed to understand the fundamental processes in a local reconnection layer both in space and laboratory plasmas. While the understanding of the global reconnection dynamics is less developed, notable findings have been made on this issue through detailed documentation of magnetic self-organization phenomena in fusion plasmas. Application of magnetic reconnection physics to astrophysical plasmas is also brie y discussed.

  13. Patterned Magnetic Nanostructures and Quantized Magnetic Disks

    E-Print Network [OSTI]

    -increasing demands in data storage and to new applications of magnetic devices in the field of sensors. NewPatterned Magnetic Nanostructures and Quantized Magnetic Disks STEPHEN Y. CHOU Invited Paper, opens up new opportunities for engineering innovative magnetic materials and devices, developing ultra

  14. SPIE Medical Imaging Medical Imaging

    E-Print Network [OSTI]

    Miga, Michael I.

    CT and SPECT (GE Hawkeye) SPIE Medical Imaging 2006 28 CT/PET System Combined CT and PET (Siemens Medical Imaging 2006 10 Computed Tomography (CT) 3D Tomography from multiple projections #12;6 SPIE: Scintillation Camera SPIE Medical Imaging 2006 26 PET and SPECT PET = Positron Emission Tomography SPECT

  15. An optimized magnet for magnetic refrigeration

    E-Print Network [OSTI]

    Bjørk, R; Smith, A; Christensen, D V; Pryds, N

    2014-01-01T23:59:59.000Z

    A magnet designed for use in a magnetic refrigeration device is presented. The magnet is designed by applying two general schemes for improving a magnet design to a concentric Halbach cylinder magnet design and dimensioning and segmenting this design in an optimum way followed by the construction of the actual magnet. The final design generates a peak value of 1.24 T, an average flux density of 0.9 T in a volume of 2 L using only 7.3 L of magnet, and has an average low flux density of 0.08 T also in a 2 L volume. The working point of all the permanent magnet blocks in the design is very close to the maximum energy density. The final design is characterized in terms of a performance parameter, and it is shown that it is one of the best performing magnet designs published for magnetic refrigeration.

  16. In Vivo Imaging with a Cell-Permeable Porphyrin-Based MRI Contrast

    E-Print Network [OSTI]

    Lee, Taekwan

    Magnetic resonance imaging (MRI) with molecular probes offers the potential to monitor physiological parameters with comparatively high spatial and temporal resolution in living subjects. For detection of intracellular ...

  17. In vivo imaging with a cell-permeable porphyrin-based MRI contrast agent

    E-Print Network [OSTI]

    Lee, Taekwan

    Magnetic resonance imaging (MRI) with molecular probes offers the potential to monitor physiological parameters with comparatively high spatial and temporal resolution in living subjects. For detection of intracellular ...

  18. Solar nebula magnetic fields recorded in the Semarkona meteorite

    E-Print Network [OSTI]

    Fu, Roger R.; Weiss, Benjamin P.; Lima, Eduardo A.; Harrison, Richard J.; Bai, Xue-Ning; Desch, Steven J.; Ebel, Denton S.; Suavet, Clement; Wang, Huapei; Glenn, David; Le Sage, David; Kasama, Takeshi; Walsworth, Ronald L.; Kuan, Aaron T.

    2014-11-13T23:59:59.000Z

    images of all three vector 492   components of the magnetic field produced by the sample in the plane of NV sensors using 493   optically-detected magnetic resonance (ODMR) spectroscopy. In this technique, described by 494   Le Sage et al. (74...   Figure 1. Dusty olivine-bearing chondrules from the Semarkona meteorite. (A) Optical 224   photomicrograph of chondrule DOC4 showing the location of dusty olivine grains. Image taken 225   in reflected light with crossed polarizers. (B) Annular...

  19. One dimensional electron spin imaging for single spin detection and manipulation using a gradient field 

    E-Print Network [OSTI]

    Shin, Chang-Seok

    2009-05-15T23:59:59.000Z

    magnetic field gradients. These fabricated devices are used to demonstrate this subwavelength imaging technique by imaging single electron spins of the nitrogen-vacancy (NV) defect in diamond. In this demonstration, multiple NV defects, unresolved in a...

  20. One dimensional electron spin imaging for single spin detection and manipulation using a gradient field

    E-Print Network [OSTI]

    Shin, Chang-Seok

    2009-05-15T23:59:59.000Z

    magnetic field gradients. These fabricated devices are used to demonstrate this subwavelength imaging technique by imaging single electron spins of the nitrogen-vacancy (NV) defect in diamond. In this demonstration, multiple NV defects, unresolved in a...

  1. Knowledge discovery using data mined from Nuclear Magnetic

    E-Print Network [OSTI]

    Narasayya, Vivek

    Knowledge discovery using data mined from Nuclear Magnetic Resonance spectral images William J cyberinfrastructure · Method ­ Solid State ab initio calculations ­ Nuclear Magnetic Resonance (NMR) ­ Support Vector refined (and/or relaxed) structure, perform Self-Consistent Field calculation for electronic structure

  2. Wavelets in medical imaging

    SciTech Connect (OSTI)

    Zahra, Noor e; Sevindir, Huliya A.; Aslan, Zafar; Siddiqi, A. H. [Sharda University, SET, Department of Electronics and Communication, Knowledge Park 3rd, Gr. Noida (India); University of Kocaeli, Department of Mathematics, 41380 Kocaeli (Turkey); Istanbul Aydin University, Department of Computer Engineering, 34295 Istanbul (Turkey); Sharda University, SET, Department of Mathematics, 32-34 Knowledge Park 3rd, Greater Noida (India)

    2012-07-17T23:59:59.000Z

    The aim of this study is to provide emerging applications of wavelet methods to medical signals and images, such as electrocardiogram, electroencephalogram, functional magnetic resonance imaging, computer tomography, X-ray and mammography. Interpretation of these signals and images are quite important. Nowadays wavelet methods have a significant impact on the science of medical imaging and the diagnosis of disease and screening protocols. Based on our initial investigations, future directions include neurosurgical planning and improved assessment of risk for individual patients, improved assessment and strategies for the treatment of chronic pain, improved seizure localization, and improved understanding of the physiology of neurological disorders. We look ahead to these and other emerging applications as the benefits of this technology become incorporated into current and future patient care. In this chapter by applying Fourier transform and wavelet transform, analysis and denoising of one of the important biomedical signals like EEG is carried out. The presence of rhythm, template matching, and correlation is discussed by various method. Energy of EEG signal is used to detect seizure in an epileptic patient. We have also performed denoising of EEG signals by SWT.

  3. Superconducting Magnet Division

    E-Print Network [OSTI]

    Gupta, Ramesh

    Superconducting Magnet Division Permanent Magnet Designs with Large Variations in Field Strength the residual field of the magnetized bricks by concentrating flux lines at the iron pole. Low Field Design Medium Field Design Superconducting Magnet Division Dipole and Quadrupole Magnets for RHIC e

  4. Superconducting magnet

    DOE Patents [OSTI]

    Satti, John A. (Naperville, IL)

    1980-01-01T23:59:59.000Z

    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.

  5. Current-driven Domain Wall Dynamics And Its Electric Signature In Ferromagnetic Nanowires

    E-Print Network [OSTI]

    Liu, Yang

    2012-10-19T23:59:59.000Z

    We study current-induced domain wall dynamics in a thin ferromagnetic nanowire. We derive the effective equations of domain wall motion, which depend on the wire geometry and material parameters. We describe the procedure to determine...

  6. Characteristics of a Direct Current-driven plasma jet operated in open air

    SciTech Connect (OSTI)

    Li, Xuechen; Bao, Wenting [College of Physics Science and Technology, Hebei University, Baoding 071002 (China) [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Key Laboratory of Photo-Electronics Information Materials of Hebei Province, Baoding 071002 (China); Di, Cong; Jia, Pengying [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)] [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)

    2013-09-30T23:59:59.000Z

    A DC-driven plasma jet has been developed to generate a diffuse plasma plume by blowing argon into the ambient air. The plasma plume, showing a cup shape with a diameter of several centimeters at a higher voltage, is a pulsed discharge despite a DC voltage is applied. The pulse frequency is investigated as a function of the voltage under different gap widths and gas flow rates. Results show that plasma bullets propagate from the hollow needle to the plate electrode by spatially resolved measurement. A supposition about non-electroneutral trail of the streamer is proposed to interpret these experimental phenomena.

  7. Linear calculations of edge current driven kink modes with BOUT++ code

    SciTech Connect (OSTI)

    Li, G. Q., E-mail: ligq@ipp.ac.cn; Xia, T. Y. [Institute of Plasma Physics, CAS, Hefei, Anhui 230031 (China); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Xu, X. Q. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Snyder, P. B.; Turnbull, A. D. [General Atomics, San Diego, California 92186 (United States); Ma, C. H.; Xi, P. W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); FSC, School of Physics, Peking University, Beijing 100871 (China)

    2014-10-15T23:59:59.000Z

    This work extends previous BOUT++ work to systematically study the impact of edge current density on edge localized modes, and to benchmark with the GATO and ELITE codes. Using the CORSICA code, a set of equilibria was generated with different edge current densities by keeping total current and pressure profile fixed. Based on these equilibria, the effects of the edge current density on the MHD instabilities were studied with the 3-field BOUT++ code. For the linear calculations, with increasing edge current density, the dominant modes are changed from intermediate-n and high-n ballooning modes to low-n kink modes, and the linear growth rate becomes smaller. The edge current provides stabilizing effects on ballooning modes due to the increase of local shear at the outer mid-plane with the edge current. For edge kink modes, however, the edge current does not always provide a destabilizing effect; with increasing edge current, the linear growth rate first increases, and then decreases. In benchmark calculations for BOUT++ against the linear results with the GATO and ELITE codes, the vacuum model has important effects on the edge kink mode calculations. By setting a realistic density profile and Spitzer resistivity profile in the vacuum region, the resistivity was found to have a destabilizing effect on both the kink mode and on the ballooning mode. With diamagnetic effects included, the intermediate-n and high-n ballooning modes can be totally stabilized for finite edge current density.

  8. Nanoscale Diffusion Studies of Lipid Membranes National High Magnetic Field Laboratory

    E-Print Network [OSTI]

    Weston, Ken

    Magnetic Resonance Imaging & Spectroscopy User Facility, University of Florida Chemical Engineering We haveNanoscale Diffusion Studies of Lipid Membranes National High Magnetic Field Laboratory Advanced for the facility's future use. This will serve to enhance infrastructure for research and education at the Magnet

  9. Nanostructured magnetic materials

    E-Print Network [OSTI]

    Chan, Keith T.

    2011-01-01T23:59:59.000Z

    Magnetism and Magnetic Materials Conference, Atlanta, GA (Nanostructured Magnetic Materials by Keith T. Chan Doctor ofinduced by a Si-based material occurs at a Si/Ni interface

  10. Interface Magnetism in Multiferroics

    E-Print Network [OSTI]

    He, Qing

    2011-01-01T23:59:59.000Z

    1.2.1 Magnetism . . . . . . . . . . . . . . . . . . . 1.2.2domain walls . . . . . 3 Magnetism of domain walls in BiFeOof electrical control of magnetism in mixed phase BiFeO 3

  11. Laced permanent magnet quadrupole drift tube magnets

    SciTech Connect (OSTI)

    Feinberg, B.; Behrsing, G.U.; Halbach, K.; Marks, J.S.; Morrison, M.E.; Nelson, D.H.

    1989-03-01T23:59:59.000Z

    Twenty-three laced permanent magnet quadrupole drift tube magnets have been constructed, tested, and installed in the SuperHILAC heavy ion linear accelerator at LBL, marking the first accelerator use of this new type of quadrupole. The magnets consist of conventional tape-wound quadrupole electromagnets, using iron pole-pieces, with permanent magnet material (samarium cobalt) inserted between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in an asymmetrical saturation curve. Since the polarity of the individual quadrupole magnets in a drift tube linac is never reversed, we can take advantage of this asymmetrical saturation to provide about 20% greater focusing strength than is available with conventional quadrupoles, while replacing the vanadium permendur poletips with iron poletips. Comparisons between these magnets and conventional tape-wound quadrupoles will be presented. 3 refs., 5 figs.

  12. SUPERCONDUCTING MAGNETIC ENERGY STORAGE

    E-Print Network [OSTI]

    Hassenzahl, W.

    2011-01-01T23:59:59.000Z

    Superconducting 30-MJ Energy Storage Coil", Proc. 19 80 ASC,Superconducting Magnetic Energy Storage Plant", IEEE Trans.SlIperconducting Magnetic Energy Storage Unit", in Advances

  13. SUPERCONDUCTING MAGNETIC ENERGY STORAGE

    E-Print Network [OSTI]

    Hassenzahl, W.

    2011-01-01T23:59:59.000Z

    Design of the BPA Superconducting 30-MJ Energy Storagefor a Utility Scale Superconducting Magnetic Energy Storagefor a Lnrge Scale Superconducting Magnetic Energy Storage

  14. A practical acceleration algorithm for real-time imaging

    E-Print Network [OSTI]

    Sumbul, Uygar

    A practical acceleration algorithm for real-time magnetic resonance imaging (MRI) is presented. Neither separate training scans nor embedded training samples are used. The Kalman filter based algorithm provides a fast and ...

  15. Ultra-fast Imaging of Two-Phase Flow in Structured Monolith Reactors; Techniques and Data Analysis

    E-Print Network [OSTI]

    Heras, Jonathan Jaime

    This thesis will address the use of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) techniques to probe the “monolith reactor”, which consists of a structured catalyst over which reactions may occur. This reactor has emerged...

  16. Rotational hysteresis of exchange-spring magnets.

    SciTech Connect (OSTI)

    Jiang, J.S.; Bader, S.D.; Kaper, H.; Leaf, G.K.; Shull, R.D.; Shapiro, A.J.; Gornakov, V.S.; Nikitenko, V.I.; Platt, C.L.; Berkowitz, A.E.; David, S.; Fullerton, E.E.

    2002-03-27T23:59:59.000Z

    We highlight our experimental studies and micromagnetic simulations of the rotational hysteresis in exchange-spring magnets. Magneto-optical imaging and torque magnetometry measurements for SmCo/Fe exchange-spring films with uniaxial in-plane anisotropy show that the magnetization rotation created in the magnetically soft Fe layer by a rotating magnetic field is hysteretic. The rotational hysteresis is due to the reversal of the chirality of the spin spiral structure. Micromagnetic simulations reveal two reversal modes of the chirality, one at low fields due to an in-plane untwisting of the spiral, and the other, at high fields, due to an out-of-plane fanning of the spiral.

  17. Laced permanent magnet quadrupole drift tube magnets

    SciTech Connect (OSTI)

    Feinberg, B.; Behrsing, G.U.; Halbach, K.; Marks, J.S.; Morrison, M.E.; Nelson, D.H.

    1988-10-01T23:59:59.000Z

    A laced permanent magnet quadrupole drift tube magnet has been constructed for a proof-of-principle test. The magnet is a conventional tape-wound quadrupole electromagnet, using iron pole- pieces, with the addition of permanent magnet material (neodymium iron) between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in an asymmetrical saturation curve. Since the polarity of the quadrupole magnets in a drift tube linac is not reversed we can take advantage of this asymmetrical saturation to provide greater focusing strength. The magnet configuration has been optimized and the vanadium permendur poles needed in a conventional quadrupole have been replaced with iron poles. The use of permanent magnet material has allowed us to increase the focusing strength of the magnet by about 20% over that of a conventional tape-wound quadrupole. Comparisons will be made between this magnet and the conventional tape-wound quadrupole. 3 refs., 5 figs.

  18. Microscopy image segmentation tool: Robust image data analysis

    SciTech Connect (OSTI)

    Valmianski, Ilya, E-mail: ivalmian@ucsd.edu; Monton, Carlos; Schuller, Ivan K. [Department of Physics and Center for Advanced Nanoscience, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States)] [Department of Physics and Center for Advanced Nanoscience, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States)

    2014-03-15T23:59:59.000Z

    We present a software package called Microscopy Image Segmentation Tool (MIST). MIST is designed for analysis of microscopy images which contain large collections of small regions of interest (ROIs). Originally developed for analysis of porous anodic alumina scanning electron images, MIST capabilities have been expanded to allow use in a large variety of problems including analysis of biological tissue, inorganic and organic film grain structure, as well as nano- and meso-scopic structures. MIST provides a robust segmentation algorithm for the ROIs, includes many useful analysis capabilities, and is highly flexible allowing incorporation of specialized user developed analysis. We describe the unique advantages MIST has over existing analysis software. In addition, we present a number of diverse applications to scanning electron microscopy, atomic force microscopy, magnetic force microscopy, scanning tunneling microscopy, and fluorescent confocal laser scanning microscopy.

  19. Image Fusion for MR Bias Stochastic Systems Group

    E-Print Network [OSTI]

    Willsky, Alan S.

    We can target T1 and T2 through appropriate selection of TE and TR. #12;Image Reconstruction The MRImage Fusion for MR Bias Correction Ayres Fan Stochastic Systems Group Joint work with W. Wells, J. Fisher, M. Cetin, S. Haker, A. Willsky, B. Mulkern #12;Magnetic Resonance The magnetic resonance (MR

  20. Introduction Magnetic Anisotropy of

    E-Print Network [OSTI]

    Rossak, Wilhelm R.

    not completely understood interesting for dilute magnetic semiconductors (DMSs) transparent ferromagnets

  1. Superconducting Magnet Division

    E-Print Network [OSTI]

    McDonald, Kirk

    Superconducting Magnet Division Ramesh Gupta 20T Target Solenoid with HTS Insert Solenoid Capture Laboratory New York, USA http://www.bnl.gov/magnets/staff/gupta #12;Superconducting Magnet Division Ramesh of HTS may significantly reduce the amount of Tungsten shielding · Summary #12;Superconducting Magnet

  2. Nanocomposite Magnets: Transformational Nanostructured Permanent Magnets

    SciTech Connect (OSTI)

    None

    2010-10-01T23:59:59.000Z

    Broad Funding Opportunity Announcement Project: GE is using nanomaterials technology to develop advanced magnets that contain fewer rare earth materials than their predecessors. Nanomaterials technology involves manipulating matter at the atomic or molecular scale, which can represent a stumbling block for magnets because it is difficult to create a finely grained magnet at that scale. GE is developing bulk magnets with finely tuned structures using iron-based mixtures that contain 80% less rare earth materials than traditional magnets, which will reduce their overall cost. These magnets will enable further commercialization of HEVs, EVs, and wind turbine generators while enhancing U.S. competitiveness in industries that heavily utilize these alternatives to rare earth minerals.

  3. Image Fusion and Registration a Variational Bernd Fischer1

    E-Print Network [OSTI]

    Modersitzki, Jan

    Image Fusion and Registration ­ a Variational Approach Bernd Fischer1 and Jan Modersitzki1 Institute of Mathematics, Wallstra�e 40, D-23560 L¨ubeck, Germany fischer@math.uni-luebeck.de, modersitzki, including the registration of magnetic resonance images of a female breast subject to some volume preserving

  4. Roadmap: Radiologic Imaging Sciences -Computed Tomography (with AAS Radiologic Technology) -

    E-Print Network [OSTI]

    Sheridan, Scott

    Roadmap: Radiologic Imaging Sciences - Computed Tomography (with AAS Radiologic Technology 34084 Computed Tomography and Magnetic Resonance Imaging Sectional Anatomy I 2 C RIS 44021 Patient Management in Computed Tomography (CT) 2 C RIS 44025 Computed Tomography (CT) Clinical Education I 3 C

  5. Roadmap: Radiologic Imaging Sciences -Computed Tomography (with AAS Radiologic Technology) -

    E-Print Network [OSTI]

    Sheridan, Scott

    Roadmap: Radiologic Imaging Sciences - Computed Tomography (with AAS Radiologic Technology] Note: Admission to the program is required to enroll in RIS courses RIS 34084 Computed Tomography and Magnetic Resonance Imaging Sectional Anatomy I 2 C RIS 44021 Patient Management in Computed Tomography 2

  6. Prediction-Based Compression Ratio Boundaries for Medical Images

    E-Print Network [OSTI]

    Qi, Xiaojun

    Prediction-Based Compression Ratio Boundaries for Medical Images Xiaojun Qi Computer Science present prediction-based image compression techniques take advantage of either intra- or inter function. The prediction-based compression technique has been applied on some magnetic resonance (MR) brain

  7. Bayesian Video Dejittering By BV Image Model Jianhong Shen

    E-Print Network [OSTI]

    Bayesian Video Dejittering By BV Image Model Jianhong Shen School of Mathematics University horizontal displacement in video images, occurs when the synchronization signals are corrupted in video storage media, or by electro- magnetic interference in wireless video transmission. The goal of intrinsic

  8. Magnetic infrasound sensor

    DOE Patents [OSTI]

    Mueller, Fred M. (Los Alamos, NM); Bronisz, Lawrence (Los Alamos, NM); Grube, Holger (Los Alamos, NM); Nelson, David C. (Santa Fe, NM); Mace, Jonathan L. (Los Alamos, NM)

    2006-11-14T23:59:59.000Z

    A magnetic infrasound sensor is produced by constraining a permanent magnet inside a magnetic potential well above the surface of superconducting material. The magnetic infrasound sensor measures the position or movement of the permanent magnet within the magnetic potential well, and interprets the measurements. Infrasound sources can be located and characterized by combining the measurements from one or more infrasound sensors. The magnetic infrasound sensor can be tuned to match infrasound source types, resulting in better signal-to-noise ratio. The present invention can operate in frequency modulation mode to improve sensitivity and signal-to-noise ratio. In an alternate construction, the superconductor can be levitated over a magnet or magnets. The system can also be driven, so that time resolved perturbations are sensed, resulting in a frequency modulation version with improved sensitivity and signal-to-noise ratio.

  9. Magnetic fields, spots and weather in chemically peculiar stars

    E-Print Network [OSTI]

    O. Kochukhov

    2007-11-30T23:59:59.000Z

    New observational techniques and sophisticated modelling methods has led to dramatic breakthroughs in our understanding of the interplay between the surface magnetism, atomic diffusion and atmospheric dynamics in chemically peculiar stars. Magnetic Doppler images, constructed using spectropolarimetric observations of Ap stars in all four Stokes parameters, reveal the presence of small-scale field topologies. Abundance Doppler mapping has been perfected to the level where distributions of many different chemical elements can be deduced self-consistently for one star. The inferred chemical spot structures are diverse and do not always trace underlying magnetic field geometry. Moreover, horizontal chemical inhomogeneities are discovered in non-magnetic CP stars and evolving chemical spots are observed for the first time in the bright mercury-manganese star alpha And. These results show that in addition to magnetic fields, another important non-magnetic structure formation mechanism acts in CP stars.

  10. Bioinspired synthesis of magnetic nanoparticles

    SciTech Connect (OSTI)

    David, Anand

    2009-05-26T23:59:59.000Z

    The synthesis of magnetic nanoparticles has long been an area of active research. Magnetic nanoparticles can be used in a wide variety of applications such as magnetic inks, magnetic memory devices, drug delivery, magnetic resonance imaging (MRI) contrast agents, and pathogen detection in foods. In applications such as MRI, particle uniformity is particularly crucial, as is the magnetic response of the particles. Uniform magnetic particles with good magnetic properties are therefore required. One particularly effective technique for synthesizing nanoparticles involves biomineralization, which is a naturally occurring process that can produce highly complex nanostructures. Also, the technique involves mild conditions (ambient temperature and close to neutral pH) that make this approach suitable for a wide variety of materials. The term 'bioinspired' is important because biomineralization research is inspired by the naturally occurring process, which occurs in certain microorganisms called 'magnetotactic bacteria'. Magnetotactic bacteria use biomineralization proteins to produce magnetite crystals having very good uniformity in size and morphology. The bacteria use these magnetic particles to navigate according to external magnetic fields. Because these bacteria synthesize high quality crystals, research has focused on imitating aspects of this biomineralization in vitro. In particular, a biomineralization iron-binding protein found in a certain species of magnetotactic bacteria, magnetospirillum magneticum, AMB-1, has been extracted and used for in vitro magnetite synthesis; Pluronic F127 gel was used to increase the viscosity of the reaction medium to better mimic the conditions in the bacteria. It was shown that the biomineralization protein mms6 was able to facilitate uniform magnetite synthesis. In addition, a similar biomineralization process using mms6 and a shorter version of this protein, C25, has been used to synthesize cobalt ferrite particles. The overall goal of this project is to understand the mechanism of magnetite particle synthesis in the presence of the biomineralization proteins, mms6 and C25. Previous work has hypothesized that the mms6 protein helps to template magnetite and cobalt ferrite particle synthesis and that the C25 protein templates cobalt ferrite formation. However, the effect of parameters such as the protein concentration on the particle formation is still unknown. It is expected that the protein concentration significantly affects the nucleation and growth of magnetite. Since the protein provides iron-binding sites, it is expected that magnetite crystals would nucleate at those sites. In addition, in the previous work, the reaction medium after completion of the reaction was in the solution phase, and magnetic particles had a tendency to fall to the bottom of the medium and aggregate. The research presented in this thesis involves solid Pluronic gel phase reactions, which can be studied readily using small-angle x-ray scattering, which is not possible for the solution phase experiments. In addition, the concentration effect of both of the proteins on magnetite crystal formation was studied.

  11. Brushed permanent magnet DC MLC motor operation in an external magnetic field

    SciTech Connect (OSTI)

    Yun, J.; St Aubin, J.; Rathee, S.; Fallone, B. G. [Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2010-05-15T23:59:59.000Z

    Purpose: Linac-MR systems for real-time image-guided radiotherapy will utilize the multileaf collimators (MLCs) to perform conformal radiotherapy and tumor tracking. The MLCs would be exposed to the external fringe magnetic fields of the linac-MR hybrid systems. Therefore, an experimental investigation of the effect of an external magnetic field on the brushed permanent magnet DC motors used in some MLC systems was performed. Methods: The changes in motor speed and current were measured for varying external magnetic field strengths up to 2000 G generated by an EEV electromagnet. These changes in motor characteristics were measured for three orientations of the motor in the external magnetic field, mimicking changes in motor orientations due to installation and/or collimator rotations. In addition, the functionality of the associated magnetic motor encoder was tested. The tested motors are used with the Varian 120 leaf Millennium MLC (Maxon Motor half leaf and full leaf motors) and the Varian 52 leaf MKII MLC (MicroMo Electronics leaf motor) including a carriage motor (MicroMo Electronics). Results: In most cases, the magnetic encoder of the motors failed prior to any damage to the gearbox or the permanent magnet motor itself. This sets an upper limit of the external magnetic field strength on the motor function. The measured limits of the external magnetic fields were found to vary by the motor type. The leaf motor used with a Varian 52 leaf MKII MLC system tolerated up to 450{+-}10 G. The carriage motor tolerated up to 2000{+-}10 G field. The motors used with the Varian 120 leaf Millennium MLC system were found to tolerate a maximum of 600{+-}10 G. Conclusions: The current Varian MLC system motors can be used for real-time image-guided radiotherapy coupled to a linac-MR system, provided the fringe magnetic fields at their locations are below the determined tolerance levels. With the fringe magnetic fields of linac-MR systems expected to be larger than the tolerance levels determined, some form of magnetic shielding would be required.

  12. Tamper resistant magnetic stripes

    DOE Patents [OSTI]

    Naylor, Richard Brian (Albuquerque, NM); Sharp, Donald J. (Albuquerque, NM)

    1999-01-01T23:59:59.000Z

    This invention relates to a magnetic stripe comprising a medium in which magnetized particles are suspended and in which the encoded information is recorded by actual physical rotation or alignment of the previously magnetized particles within the flux reversals of the stripe which are 180.degree. opposed in their magnetic polarity. The magnetized particles are suspended in a medium which is solid, or physically rigid, at ambient temperatures but which at moderately elevated temperatures, such as 40.degree. C., is thinable to a viscosity permissive of rotation of the particles therein under applications of moderate external magnetic field strengths within acceptable time limits.

  13. Journal of Magnetism and Magnetic Materials ] (

    E-Print Network [OSTI]

    McHenry, Michael E.

    magnetic properties were measured with a vibrating sample magnetometer. The mass-specific power loss.40.Rs Keywords: Nanocrystalline alloys; Amorphous alloys; Field annealing; Power loss; Soft magnets the hysteretic power loss while maintaining high-temperature operability [4]. Other goals have included studies

  14. Magnetic Materials Group

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for magnetic circular dichroism (XMCD) and magnetic scattering experiments. Sunset Yellow 6-ID-B: Resonant and In-Field Scattering Beamline 6-ID-B,C is the primary beamline on...

  15. Recent lunar magnetism

    E-Print Network [OSTI]

    Buz, Jennifer

    2011-01-01T23:59:59.000Z

    The magnetization of young lunar samples (magnetic fields (e.g. core dynamo and long-lived impact plasma fields) have not been present within the last 1.5 Ga. To better ...

  16. Active magnetic regenerator

    DOE Patents [OSTI]

    Barclay, John A. (Los Alamos, NM); Steyert, William A. (Los Alamos, NM)

    1982-01-01T23:59:59.000Z

    The disclosure is directed to an active magnetic regenerator apparatus and method. Brayton, Stirling, Ericsson, and Carnot cycles and the like may be utilized in an active magnetic regenerator to provide efficient refrigeration over relatively large temperature ranges.

  17. Permanent magnet with MgB{sub 2} bulk superconductor

    SciTech Connect (OSTI)

    Yamamoto, Akiyasu, E-mail: yamamoto@appchem.t.u-tokyo.ac.jp [The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); JST-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Ishihara, Atsushi; Tomita, Masaru [Railway Technical Research Institute, 2-8-38 Hikari, Kokubunji, Tokyo 185-8540 (Japan); Kishio, Kohji [The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan)

    2014-07-21T23:59:59.000Z

    Superconductors with persistent zero-resistance currents serve as permanent magnets for high-field applications requiring a strong and stable magnetic field, such as magnetic resonance imaging. The recent global helium shortage has quickened research into high-temperature superconductors (HTSs)—materials that can be used without conventional liquid-helium cooling to 4.2?K. Herein, we demonstrate that 40-K-class metallic HTS magnesium diboride (MgB{sub 2}) makes an excellent permanent bulk magnet, maintaining 3?T at 20?K for 1 week with an extremely high stability (<0.1 ppm/h). The magnetic field trapped in this magnet is uniformly distributed, as for single-crystalline neodymium-iron-boron. Magnetic hysteresis loop of the MgB{sub 2} permanent bulk magnet was determined. Because MgB{sub 2} is a simple-binary-line compound that does not contain rare-earth metals, polycrystalline bulk material can be industrially fabricated at low cost and with high yield to serve as strong magnets that are compatible with conventional compact cryocoolers, making MgB{sub 2} bulks promising for the next generation of Tesla-class permanent-magnet applications.

  18. X-Ray Diffraction Microscopy of Magnetic Structures

    SciTech Connect (OSTI)

    Turner, J.; Lima, E.; Huang, X.; Krupin, O.; Seu, K.; Parks, D.; Kevan, S.; Kisslinger, K.; McNulty, I.; Gambino, R.; Mangin, S.; Roy, S. and Fischer, P.

    2011-07-14T23:59:59.000Z

    We report the first proof-of-principle experiment of iterative phase retrieval from magnetic x-ray diffraction. By using the resonant x-ray excitation process and coherent x-ray scattering, we show that linearly polarized soft x rays can be used to image both the amplitude and the phase of magnetic domain structures. We recovered the magnetic structure of an amorphous terbium-cobalt thin film with a spatial resolution of about 75 nm at the Co L{sub 3} edge at 778 eV. In comparison with soft x-ray microscopy images recorded with Fresnel zone plate optics at better than 25 nm spatial resolution, we find qualitative agreement in the observed magnetic structure.

  19. Magnetism Theory Group / POSTECH Magnetism Theory Group / POSTECH

    E-Print Network [OSTI]

    Min, Byung Il

    Magnetism Theory Group / POSTECH #12;Magnetism Theory Group / POSTECH #12;Magnetism Theory Group / POSTECH #12;Magnetism Theory Group / POSTECH #12;Magnetism Theory Group / POSTECH J.H . Park et al. #12;'s of FeinCsm e tal The chargeandorbitalordering geom etryin YB a C o 2 O 5 S. K. Kwon etal .Magnetism Theory

  20. Magnetic susceptibility in QCD

    E-Print Network [OSTI]

    V. D. Orlovsky; Yu. A. Simonov

    2014-05-12T23:59:59.000Z

    Magnetic susceptibility in the deconfined phase of QCD is calculated in a closed form using a recent general expression for the quark gas pressure in magnetic field. Quark selfenergies are entering the result via Polyakov line factors and ensure the total paramagnetic effect, increasing with temperature. A generalized form of magnetic susceptibility in nonzero magnetic field suitable for experimental and lattice measurements is derived, showing a good agreement with available lattice data.

  1. Status of LDRD-DR 20070518 development of a magnetically driven target for thermo-nuclear burn studies (u)

    SciTech Connect (OSTI)

    Watt, Robert G [Los Alamos National Laboratory; Atchison, W L [Los Alamos National Laboratory; Colgate, S A [Los Alamos National Laboratory; Goforth, J [Los Alamos National Laboratory; Griego, J [Los Alamos National Laboratory; Guzik, J [Los Alamos National Laboratory; Holtkamp, D [Los Alamos National Laboratory; Idzorek, G [Los Alamos National Laboratory; Kirkpatrick, R [Los Alamos National Laboratory; Menikoff, R [Los Alamos National Laboratory; Meyer, R [Los Alamos National Laboratory; Oona, H [Los Alamos National Laboratory; Reardon, P [Los Alamos National Laboratory; Rousculp, C L [Los Alamos National Laboratory; Sgro, A G [Los Alamos National Laboratory; Tabaka, L [Los Alamos National Laboratory

    2010-01-20T23:59:59.000Z

    This project is developing a magnetically driven cylindrical confinement system for the creation of a small region of material existing under extreme conditions. Using a Ranchero High Explosive Pulsed Power generator (HEPP) with maximum current ranging from 25- 50 MA depending on the load, a current driven Al cylinder will impact a series of nested, less massive Au shells. Each subsequent shell's inner surface velocity will increase due to it's smaller mass by the ratio 2.01( 1+ m{sub i+ 1}/m i), along with radial convergence. Attaining this ideal result requires highly efficient energy transfer which in turn requires plastic cushions. The final velocity of the last sequential shell will be used to drive a central experimental package in which extreme material conditions will be produced. The inexpensive nature of HEPP and the extreme conditions attainable allow many studies to be conducted in regimes not currently available in the laboratory. One potential central experimental package consists of a cylindrical Inertial Confinement Fusion (ICF) target; a cylindrical Au pusher surrounding frozen DT. This target is used as a design tool. The ICF conditions achieved with such a target would be similar to those created in a double shell ignition capsule at the National Ignition Facility. The system being developed has a range of potential applications.

  2. Hyperspectral Imaging or Imaging Spectroscopy

    E-Print Network [OSTI]

    Gilbes, Fernando

    (nm) Cosmic Rays Gamma Rays X Rays Microwaves (Radar) Radio & Television WavesUV 105 106 107 108 109 the image cube by scanning through it. The conventional methods are whiskbroom (a), filter/Fourier transform Optics Scene FOVx X-Dimension Scanning Mechanism Focusing Optics #12;Whiskbroom Sensor Accumulation

  3. Integrating an automatic classification method into the medical image retrieval process

    E-Print Network [OSTI]

    Ruiz, Miguel E.

    the performance of the University at Buffalo Medical Text and Images Retrieval System (UBMedTIRS). This paper classification process was performed using the Image Retrieval for Medical Application (IRMA) codes3 employed to acquire the image such as x-ray, ultrasound, magnetic resonance measurement, nuclear medicine

  4. Dynamic Surface Reconstruction from 4D-MR Images Matthias Fenchel1

    E-Print Network [OSTI]

    Gumhold, Stefan

    Dynamic Surface Reconstruction from 4D-MR Images Matthias Fenchel1 , Stefan Gumhold2 , Hans approach is applied to 4D-MR images of a human heart in motion. 1 Introduction Image segmentation-Peter Seidel3 1 Siemens AG Medical Solutions, Magnetic Resonance, Karl-Schall-Str. 4, 91052 Erlangen 2 TU

  5. Image-based fluidstructure interaction model of the human mitral valve Xingshuang Ma a

    E-Print Network [OSTI]

    Luo, Xiaoyu

    Image-based fluid­structure interaction model of the human mitral valve Xingshuang Ma a , Hao Gao Available online 15 November 2012 Keywords: Human mitral valve Clinical imaging Magnetic resonance imaging Fluid­structure interaction Immersed boundary method a b s t r a c t The mitral valve (MV) is one

  6. TRACKING TONGUE MOTION IN THREE DIMENSIONS USING TAGGED MR IMAGES Xiaofeng Liu1

    E-Print Network [OSTI]

    Prince, Jerry L.

    TRACKING TONGUE MOTION IN THREE DIMENSIONS USING TAGGED MR IMAGES Xiaofeng Liu1 , Maureen Stone3 and strain analysis of tagged magnetic res- onance (MR) imaging [1]. It was originally applied to car- diac This research was supported by NIH grants R01 HL047405 and R01 DC001758 (a) (b) Fig. 1. (a) A tagged MR image

  7. Noble gas magnetic resonator

    DOE Patents [OSTI]

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2014-04-15T23:59:59.000Z

    Precise measurements of a precessional rate of noble gas in a magnetic field is obtained by constraining the time averaged direction of the spins of a stimulating alkali gas to lie in a plane transverse to the magnetic field. In this way, the magnetic field of the alkali gas does not provide a net contribution to the precessional rate of the noble gas.

  8. Magnetic nanohole superlattices

    DOE Patents [OSTI]

    Liu, Feng

    2013-05-14T23:59:59.000Z

    A magnetic material is disclosed including a two-dimensional array of carbon atoms and a two-dimensional array of nanoholes patterned in the two-dimensional array of carbon atoms. The magnetic material has long-range magnetic ordering at a temperature below a critical temperature Tc.

  9. A MAGNETIC CALIBRATION OF PHOTOSPHERIC DOPPLER VELOCITIES

    SciTech Connect (OSTI)

    Welsch, Brian T.; Fisher, George H. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Sun, Xudong [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2013-03-10T23:59:59.000Z

    The zero point of measured photospheric Doppler shifts is uncertain for at least two reasons: instrumental variations (from, e.g., thermal drifts); and the convective blueshift, a known correlation between intensity and upflows. Accurate knowledge of the zero point is, however, useful for (1) improving estimates of the Poynting flux of magnetic energy across the photosphere, and (2) constraining processes underlying flux cancellation, the mutual apparent loss of magnetic flux in closely spaced, opposite-polarity magnetogram features. We present a method to absolutely calibrate line-of-sight (LOS) velocities in solar active regions (ARs) near disk center using three successive vector magnetograms and one Dopplergram coincident with the central magnetogram. It exploits the fact that Doppler shifts measured along polarity inversion lines (PILs) of the LOS magnetic field determine one component of the velocity perpendicular to the magnetic field, and optimizes consistency between changes in LOS flux near PILs and the transport of transverse magnetic flux by LOS velocities, assuming that ideal electric fields govern the magnetic evolution. Previous calibrations fitted the center-to-limb variation of Doppler velocities, but this approach cannot, by itself, account for residual convective shifts at the limb. We apply our method to vector magnetograms of AR 11158, observed by the Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory, and find clear evidence of offsets in the Doppler zero point in the range of 50-550 m s{sup -1}. In addition, we note that a simpler calibration can be determined from an LOS magnetogram and Dopplergram pair from the median Doppler velocity among all near-disk-center PIL pixels. We briefly discuss shortcomings in our initial implementation, and suggest ways to address these. In addition, as a step in our data reduction, we discuss the use of temporal continuity in the transverse magnetic field direction to correct apparently spurious fluctuations in resolution of the 180 Degree-Sign ambiguity.

  10. Imaging bolometer

    DOE Patents [OSTI]

    Wurden, Glen A. (Los Alamos, NM)

    1999-01-01T23:59:59.000Z

    Radiation-hard, steady-state imaging bolometer. A bolometer employing infrared (IR) imaging of a segmented-matrix absorber of plasma radiation in a cooled-pinhole camera geometry is described. The bolometer design parameters are determined by modeling the temperature of the foils from which the absorbing matrix is fabricated by using a two-dimensional time-dependent solution of the heat conduction equation. The resulting design will give a steady-state bolometry capability, with approximately 100 Hz time resolution, while simultaneously providing hundreds of channels of spatial information. No wiring harnesses will be required, as the temperature-rise data will be measured via an IR camera. The resulting spatial data may be used to tomographically investigate the profile of plasmas.

  11. Imaging bolometer

    DOE Patents [OSTI]

    Wurden, G.A.

    1999-01-19T23:59:59.000Z

    Radiation-hard, steady-state imaging bolometer is disclosed. A bolometer employing infrared (IR) imaging of a segmented-matrix absorber of plasma radiation in a cooled-pinhole camera geometry is described. The bolometer design parameters are determined by modeling the temperature of the foils from which the absorbing matrix is fabricated by using a two-dimensional time-dependent solution of the heat conduction equation. The resulting design will give a steady-state bolometry capability, with approximately 100 Hz time resolution, while simultaneously providing hundreds of channels of spatial information. No wiring harnesses will be required, as the temperature-rise data will be measured via an IR camera. The resulting spatial data may be used to tomographically investigate the profile of plasmas. 2 figs.

  12. Magnetic domain structure and magnetization reversal in submicron-scale Co dots

    SciTech Connect (OSTI)

    Fernandez, A., LLNL

    1998-02-17T23:59:59.000Z

    We present a magnetic force microscopy (MFM) analysis of arrays of submicron-scale Co dots fabricated by interference lithography. The dots are thin (180-300 A) and are elliptical in shape. MFM of these structures reveals that they relax into highly ordered remanent states whose symmetry and configuration are governed by their shape anisotropy. In particular, when the dots are saturated along the easy-axis, a uniformly magnetized state persists at remanence. However, when the dots are saturated in hard-axis, they relax into a single-vortex state in which the circulation can have either sign. Both remanent states are characterized by smoothly varying magnetization patterns and a high degree of uniformity across the array. We attribute the ordered behavior of these structures to the film microstructure, which allows the shape anisotropy to dominate over magnetocrystalline anisotropy. By imaging a series of minor-loop remanent states, we show that magnetization reversal in these structures occurs via the nucleation and annihilation of a single vortex. Magnetic hysteresis loop measurements are consistent with these observations and provide additional details. Furthermore, we present the results of micromagnetic simulations, which are in excellent agreement with both the MFM images and the hysteresis loop measurements.

  13. Magnetically attached sputter targets

    DOE Patents [OSTI]

    Makowiecki, D.M.; McKernan, M.A.

    1994-02-15T23:59:59.000Z

    An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material is described. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly. 11 figures.

  14. The chiral magnetic nanomotors

    E-Print Network [OSTI]

    Morozov, Konstantin I

    2013-01-01T23:59:59.000Z

    Propulsion of the chiral magnetic nanomotors powered by a rotating magnetic field is in the focus of the modern biomedical applications. This technology relies on strong interaction of dynamic and magnetic degrees of freedom of the system. Here we study in detail various experimentally observed regimes of the helical nanomotor orientation and propulsion depending on the actuation frequency, and establish the relation of these two properties with remanent magnetization and geometry of the helical nanomotors. The theoretical predictions for the transition between the regimes and nanomotor orientation and propulsion speed are in excellent agreement with available experimental data. The proposed theory offers a few simple guidelines towards the optimal design of the magnetic nanomotors. In particular, efficient nanomotors should be fabricated of hard magnetics, e.g., cobalt, magnetized transversally and have the geometry of a normal helix with a helical angle of 35-45 degrees.

  15. CONSTRAINING THREE-DIMENSIONAL MAGNETIC FIELD EXTRAPOLATIONS USING THE TWIN PERSPECTIVES OF STEREO

    SciTech Connect (OSTI)

    Conlon, Paul A.; Gallagher, Peter T. [Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2 (Ireland)

    2010-05-20T23:59:59.000Z

    The three-dimensional magnetic topology of a solar active region (NOAA 10956) was reconstructed using a linear force-free field extrapolation constrained using the twin perspectives of STEREO. A set of coronal field configurations was initially generated from extrapolations of the photospheric magnetic field observed by the Michelson Doppler Imager on SOHO. Using an EUV intensity-based cost function, the extrapolated field lines that were most consistent with 171 A passband images from the Extreme UltraViolet Imager on STEREO were identified. This facilitated quantitative constraints to be placed on the twist ({alpha}) of the extrapolated field lines, where {nabla} x B = {alpha}B. Using the constrained values of {alpha}, the evolution in time of twist, connectivity, and magnetic energy were then studied. A flux emergence event was found to result in significant changes in the magnetic topology and total magnetic energy of the region.

  16. Enhanced oil recovery through water imbibition in fractured reservoirs using Nuclear Magnetic Resonance 

    E-Print Network [OSTI]

    Hervas Ordonez, Rafael Alejandro

    1994-01-01T23:59:59.000Z

    -iicro-fracture system. Nuclear Magnetic Resonance (NNM) sets of longitudinal and transverse profiles and images were recorded to visualize and quantify changes in fluid saturation inside the rock samples during the imbibition displacement tests. NMR oil saturation...

  17. Enhanced oil recovery through water imbibition in fractured reservoirs using Nuclear Magnetic Resonance

    E-Print Network [OSTI]

    Hervas Ordonez, Rafael Alejandro

    1994-01-01T23:59:59.000Z

    -iicro-fracture system. Nuclear Magnetic Resonance (NNM) sets of longitudinal and transverse profiles and images were recorded to visualize and quantify changes in fluid saturation inside the rock samples during the imbibition displacement tests. NMR oil saturation...

  18. Development of novel high-performance six-axis magnetically levitated instruments for nanoscale applications

    E-Print Network [OSTI]

    Verma, Shobhit

    2005-11-01T23:59:59.000Z

    and the sample. While working in noncontact mode the AFM tip does not touch the sample but gets the topographic image of sample from attractive force [13]. The AFM have resolution up to 10 pm. The basic working principle of AFM is very much like a record...-earth permanent-magnet-biased magnetic-bearing suspension [48]. The permanent magnet provides bias flux and the electromagnet can increase or reduce flux of the permanent magnet. The flux path of the electromagnet does not pass through the permanent magnet so...

  19. Nanoscale magnetic field mapping with a single spin scanning probe magnetometer

    SciTech Connect (OSTI)

    Rondin, L.; Tetienne, J.-P.; Spinicelli, P.; Roch, J.-F.; Jacques, V. [Laboratoire de Photonique Quantique et Moleculaire, Ecole Normale Superieure de Cachan and CNRS UMR 8537, 94235 Cachan Cedex (France); Dal Savio, C.; Karrai, K. [Attocube systems AG, Koeniginstrasse 11A RGB, Munich 80539 (Germany); Dantelle, G. [Laboratoire de Physique de la Matiere Condensee, Ecole Polytechnique and CNRS UMR 7643, 91128 Palaiseau (France); Thiaville, A.; Rohart, S. [Laboratoire de Physique des Solides, Universite Paris-Sud and CNRS UMR 8502, 91405 Orsay (France)

    2012-04-09T23:59:59.000Z

    We demonstrate quantitative magnetic field mapping with nanoscale resolution, by applying a lock-in technique on the electron spin resonance frequency of a single nitrogen-vacancy defect placed at the apex of an atomic force microscope tip. In addition, we report an all-optical magnetic imaging technique which is sensitive to large off-axis magnetic fields, thus extending the operation range of diamond-based magnetometry. Both techniques are illustrated by using a magnetic hard disk as a test sample. Owing to the non-perturbing and quantitative nature of the magnetic probe, this work should open up numerous perspectives in nanomagnetism and spintronics.

  20. Measurement of magnetic turbulence structure and nonlinear mode coupling of tearing fluctuations in the Madison Symmetric Torus reversed field pinch edge

    SciTech Connect (OSTI)

    Assadi, S.

    1994-01-01T23:59:59.000Z

    Linear and nonlinear magnetohydrodynamic (MHD) stability of current-driven modes are studied in the MST reversed field pinch. Measured low frequency (f < 35 kHz) magnetic fluctuations are consistent with the global resistive tearing instabilities predicted by 3-D MHD simulations. At frequencies above 35 kHz, the magnetic fluctuations were detected to be localized and externally resonant. Discrete dynamo events, ``sawtooth oscillations,`` have been observed in the experimental RFP plasmas. This phenomenon causes the plasma to become unstable to m = 1 tearing modes. The modes that may be important in different phases of these oscillations are identified. These results then assist in nonlinear studies and also help to interpret the spectral broadening of the measured data during a discrete dynamo event. Three-wave nonlinear coupling of spectral Fourier modes is measured in the MST by applying bispectral analysis to magnetic fluctuations measured at the plasma edge at 64 toroidal locations and 16 poloidal locations, permitting observation of coupling over 8 poloidal and 32 toroidal modes. Comparison to bispectra predicted by resistive MHD computation indicates reasonably good agreement. However, during the crash phase of the sawtooth oscillation the nonlinear coupling is strongly enhanced, concomitant with a broadened k-spectrum. During the sawtooth formation the plasma is undergoing a pure diffusive process. The dynamo only occurs during the sawtooth crash. High frequency activity prior to a sawtooth crash is caused by nonlinear frequency (small-scale) mode coupling. Growth rate and coupling coefficients of toroidal mode spectra are calculated by statistical modeling. Temporal evolution of edge toroidal mode spectra has been predicted by transfer function analysis. The driving sources of electrostatic fields are different than for the magnetic fields. The characteristics of tearing modes can be altered by external field errors and addition of impurities to the plasma.

  1. Lensless imaging

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 -ofLearningLensless4 Lensless Imaging of

  2. Core-Shell Structured Magnetic Ternary Nanocubes

    SciTech Connect (OSTI)

    Wang, Lingyan; Wang, Xin; Luo, Jin; Wanjala, Bridgid N.; Wang, Chong M.; Chernova, Natalya; Engelhard, Mark H.; Liu, Yao; Bae, In-Tae; Zhong, Chuan-Jian

    2010-12-01T23:59:59.000Z

    While transition metal-doped ferrite nanoparticles constitute an important class of soft magnetic nanomaterials with spinel structures, the ability to control the shape and composition would enable a wide range of applications in homogeneous or heterogeneous reactions such as catalysis and magnetic separation of biomolecules. This report describes novel findings of an investigation of core-shell structured MnZn ferrite nanocubes synthesized in organic solvents by manipulating the reaction temperature and capping agent composition in the absence of the conventionally-used reducing agents. The core-shell structure of the highly-monodispersed nanocubes (~20 nm) are shown to consist of an Fe3O4 core and an (Mn0.5Zn0.5)(Fe0.9, Mn1.1)O4 shell. In comparison with Fe3O4 and other binary ferrite nanoparticles, the core-shell structured nanocubes were shown to display magnetic properties regulated by a combination of the core-shell composition, leading to a higher coercivity (~350 Oe) and field-cool/zero-field-cool characteristics drastically different from many regular MnZn ferrite nanoparticles. The findings are discussed in terms of the unique core-shell composition, the understanding of which has important implication to the exploration of this class of soft magnetic nanomaterials in many potential applications such as magnetic resonance imaging, fuel cells, and batteries.

  3. Magnetic spectroscopy and microscopy of functional materials

    SciTech Connect (OSTI)

    Jenkins, C.A.

    2011-01-28T23:59:59.000Z

    Heusler intermetallics Mn{sub 2}Y Ga and X{sub 2}MnGa (X; Y =Fe, Co, Ni) undergo tetragonal magnetostructural transitions that can result in half metallicity, magnetic shape memory, or the magnetocaloric effect. Understanding the magnetism and magnetic behavior in functional materials is often the most direct route to being able to optimize current materials for todays applications and to design novel ones for tomorrow. Synchrotron soft x-ray magnetic spectromicroscopy techniques are well suited to explore the the competing effects from the magnetization and the lattice parameters in these materials as they provide detailed element-, valence-, and site-specifc information on the coupling of crystallographic ordering and electronic structure as well as external parameters like temperature and pressure on the bonding and exchange. Fundamental work preparing the model systems of spintronic, multiferroic, and energy-related compositions is presented for context. The methodology of synchrotron spectroscopy is presented and applied to not only magnetic characterization but also of developing a systematic screening method for future examples of materials exhibiting any of the above effects. The chapter progression is as follows: an introduction to the concepts and materials under consideration (Chapter 1); an overview of sample preparation techniques and results, and the kinds of characterization methods employed (Chapter 2); spectro- and microscopic explorations of X{sub 2}MnGa/Ge (Chapter 3); spectroscopic investigations of the composition series Mn{sub 2}Y Ga to the logical Mn{sub 3}Ga endpoint (Chapter 4); and a summary and overview of upcoming work (Chapter 5). Appendices include the results of a Think Tank for the Graduate School of Excellence MAINZ (Appendix A) and details of an imaging project now in progress on magnetic reversal and domain wall observation in the classical Heusler material Co{sub 2}FeSi (Appendix B).

  4. Revealing the Degree of Magnetic Frustration by Non-Magnetic Impurities

    SciTech Connect (OSTI)

    Not Available

    2011-08-12T23:59:59.000Z

    Imaging the magnetic fields around a non-magnetic impurity can provide a clear benchmark for quantifying the degree of magnetic frustration. Focusing on the strongly frustrated J{sub 1}-J{sub 2} model and the spatially anisotropic J{sub 1a}-J{sub 1b}-J{sub 2} model, very distinct low energy behaviors reflect different levels of magnetic frustration. In the J{sub 1}-J{sub 2} model, bound magnons appear trapped near the impurity in the ground state and strongly reduce the ordered moments for sites proximal to the impurity. In contrast, local moments in the J{sub 1a}-J{sub 1b}-J{sub 2} model are enhanced on the impurity neighboring sites. These theoretical predictions can be probed by experiments such as nuclear magnetic resonance and scanning tunneling microscopy, and the results can elucidate the role of frustration in antiferromagnets and help narrow the possible models to understand magnetism in the iron pnictdies.

  5. Effect of recording condition on the diffraction efficiency of magnetic hologram with magnetic garnet films

    SciTech Connect (OSTI)

    Nakamura, Yuichi, E-mail: nakamura@ee.tut.ac.jp; Takagi, Hiroyuki; Lim, Pang Boey; Inoue, Mitsuteru [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, 1-1 Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2014-09-14T23:59:59.000Z

    A holographic memory has been attracting attention as recording media with high recording density and high data transfer rate. We have studied the magnetic garnets as a rewritable and long life media for magnetic holography. However, since the signal intensity of reconstructed image was relatively low, the effects of recording conditions on the diffraction efficiency of magnetic hologram were investigated with experiments and the numerical simulation using COMSOL multi-physics. The diffraction efficiency tends to decrease as increasing the spatial frequency, and the use of short pulse laser with the pulse width of 50 ps was found to be effective to achieve high diffraction efficiency. This suggests that the formation of clear magnetic fringe similar to interference pattern can be obtained by the use of short pulse laser since undesirable heat diffusion during radiation does not occur. On the other hand, the diffraction efficiency increased as increasing the film thickness up to 3.1??m but was saturated in the garnet film thicker than 3.1??m in the case of spatial frequency of 1500 line pair/mm. The numerical simulation showed that the effective depth of magnetic fringe was limited about 1.8??m irrespective of the garnet film thickness because the fringes were connected by thermal diffusion near the surface of the film, and the effective depth is limited due to this connection of the magnetic fringe. Avoiding this fringe connection, much higher diffraction efficiency will be achieved.

  6. Passive magnetic bearing system

    DOE Patents [OSTI]

    Post, Richard F.

    2014-09-02T23:59:59.000Z

    An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.

  7. Refreshing One of Several Active Representations: Behavioral and Functional Magnetic Resonance

    E-Print Network [OSTI]

    Johnson, Marcia K.

    Refreshing One of Several Active Representations: Behavioral and Functional Magnetic Resonance with this interpretation, in a functional magnetic resonance imaging study, young adults showed two areas of left they just opened the refrigerator door, telling a story multiple times to the same person, or forgetting

  8. A laboratory plasma experiment for studying magnetic dynamics of accretion discs and jets

    E-Print Network [OSTI]

    Hsu, Scott

    A laboratory plasma experiment for studying magnetic dynamics of accretion discs and jets S. C. Hsu into the magnetic dynamics of accretion discs and jets. A high-speed multiple-frame CCD camera reveals images of the formation and helical instability of a collimated plasma, similar to MHD models of disc jets, and also

  9. Pulse magnetic welder

    DOE Patents [OSTI]

    Christiansen, D.W.; Brown, W.F.

    1984-01-01T23:59:59.000Z

    A welder is described for automated closure of fuel pins by a pulsed magnetic process in which the open end of a length of cladding is positioned within a complementary tube surrounded by a pulsed magnetic welder. Seals are provided at each end of the tube, which can be evacuated or can receive tag gas for direct introduction to the cladding interior. Loading of magnetic rings and end caps is accomplished automatically in conjunction with the welding steps carried out within the tube.

  10. Magnetic latching solenoid

    DOE Patents [OSTI]

    Marts, Donna J. (Idaho Falls, ID); Richardson, John G. (Idaho Falls, ID); Albano, Richard K. (Idaho Falls, ID); Morrison, Jr., John L. (Idaho Falls, ID)

    1995-01-01T23:59:59.000Z

    This invention discloses a D.C. magnetic latching solenoid that retains a moving armature in a first or second position by means of a pair of magnets, thereby having a zero-power requirement after actuation. The first or second position is selected by reversing the polarity of the D.C. voltage which is enough to overcome the holding power of either magnet and transfer the armature to an opposite position. The coil is then de-energized.

  11. Magnetic nanoparticles for medical applications: Progress and challenges

    SciTech Connect (OSTI)

    Doaga, A.; Cojocariu, A. M.; Constantin, C. P.; Caltun, O. F. [Faculty of Physics, Alexandru Ioan Cuza University, Bd. Carol I. Nr. 11, Iasi, 700506 (Romania); Hempelmann, R. [Physical Chemistry Department, Saarland University, 66123 Saarbrücken (Germany)

    2013-11-13T23:59:59.000Z

    Magnetic nanoparticles present unique properties that make them suitable for applications in biomedical field such as magnetic resonance imaging (MRI), hyperthermia and drug delivery systems. Magnetic hyperthermia involves heating the cancer cells by using magnetic particles exposed to an alternating magnetic field. The cell temperature increases due to the thermal propagation of the heat induced by the nanoparticles into the affected region. In order to increase the effectiveness of the treatment hyperthermia can be combined with drug delivery techniques. As a spectroscopic technique MRI is used in medicine for the imaging of tissues especially the soft ones and diagnosing malignant or benign tumors. For this purpose Zn{sub x}Co{sub 1?x}Fe{sub 2}O{sub 4} ferrite nanoparticles with x between 0 and 1 have been prepared by co-precipitation method. The cristallite size was determined by X-ray diffraction, while the transmission electron microscopy illustrates the spherical shape of the nanoparticles. Magnetic characterizations of the nanoparticles were carried out at room temperature by using a vibrating sample magnetometer. The specific absorption rate (SAR) was measured by calorimetric method at different frequencies and it has been observed that this value depends on the chemical formula, the applied magnetic fields and the frequency. The study consists of evaluating the images, obtained from an MRI facility, when the nanoparticles are dispersed in agar phantoms compared with the enhanced ones when Omniscan was used as contrast agent. Layer-by-layer technique was used to achieve the necessary requirement of biocompatibility. The surface of the magnetic nanoparticles was modified by coating it with oppositely charged polyelectrolites, making it possible for the binding of a specific drug.

  12. Holographic Magnetic Phase Transition

    E-Print Network [OSTI]

    Gilad Lifschytz; Matthew Lippert

    2009-06-21T23:59:59.000Z

    We study four-dimensional interacting fermions in a strong magnetic field, using the holographic Sakai-Sugimoto model of intersecting D4 and D8 branes in the deconfined, chiral-symmetric parallel phase. We find that as the magnetic field is varied, while staying in the parallel phase, the fermions exhibit a first-order phase transition in which their magnetization jumps discontinuously. Properties of this transition are consistent with a picture in which some of the fermions jump to the lowest Landau level. Similarities to known magnetic phase transitions are discussed.

  13. Magnetic Braids Anthony Yeates

    E-Print Network [OSTI]

    Dundee, University of

    flux function Main result Conclusion 2. Thermonuclear confinement devices. ITER (Internat'l Thermonuclear Experimental Reactor). Inside the KSTAR tokamak. Correspond to periodic magnetic braids. 4 / 22

  14. Charge and magnetization inhomogeneities in diluted magnetic semiconductors

    E-Print Network [OSTI]

    Timm, Carsten

    2006-03-01T23:59:59.000Z

    It is predicted that III-V diluted magnetic semiconductors can exhibit stripelike modulations of magnetization and carrier concentration. This inhomogeneity results from the strong dependence of the magnetization on the carrier concentration. Within...

  15. Design and construction of a magnetic force microscope

    E-Print Network [OSTI]

    Khandekar, Sameer Sudhakar

    2005-08-29T23:59:59.000Z

    Nanotec Electronica, Spain. Fig. 6 shows the MFM images of two different hard disks. The difference in the size of the magnetic domains is evident in this case with the new hard disk having smaller domain size and the old hard disk having the larger...

  16. The magnetic resonance force microscope: A new microscopic probe of magnetic materials

    SciTech Connect (OSTI)

    Hammel, P.C.; Zhang, Z. [Los Alamos National Lab., NM (United States); Midzor, M.; Roukes, M.L. [California Inst. of Tech., Pasadena, CA (United States); Wigen, P.E. [Ohio State Univ., Columbus, OH (United States); Childress, J.R. [Univ. of Florida, Gainesville, FL (United States)

    1997-08-06T23:59:59.000Z

    The magnetic resonance force microscope (MRFM) marries the techniques of magnetic resonance imaging (MRI) and atomic force microscopy (AFM), to produce a three-dimensional imaging instrument with high, potentially atomic-scale, resolution. The principle of the MRFM has been successfully demonstrated in numerous experiments. By virtue of its unique capabilities the MRFM shows promise to make important contributions in fields ranging from three-dimensional materials characterization to bio-molecular structure determination. Here the authors focus on its application to the characterization and study of layered magnetic materials; the ability to illuminate the properties of buried interfaces in such materials is a particularly important goal. While sensitivity and spatial resolution are currently still far from their theoretical limits, they are nonetheless comparable to or superior to that achievable in conventional MRI. Further improvement of the MRFM will involve operation at lower temperature, application of larger field gradients, introduction of advanced mechanical resonators and improved reduction of the spurious coupling when the magnet is on the resonator.

  17. Journal of Magnetism and Magnetic Materials 252 (2002) 159161 Magnetically induced alignment of FNS

    E-Print Network [OSTI]

    Reznikov, Yuri

    Journal of Magnetism and Magnetic Materials 252 (2002) 159­161 Magnetically induced alignment the observation of magnetically controlled anchoring of ferro-nematic suspensions. We found that application of a weak magnetic field to a cell with the ferro-suspension induces an easy orientation axis with weak

  18. High Temperature, Permanent Magnet Biased Magnetic Bearings

    E-Print Network [OSTI]

    Gandhi, Varun R.

    2010-07-14T23:59:59.000Z

    , then the molding process was carried out to form the potting cement on the each stator. After this the stators are baked in the oven and once ready the magnets and back-irons are put onto the stator. Shown below in Figure 3-11 is an assembly tool designed... rings. The bearing and its support rings were then carried onto the test rig and mounted at one end of the table. Throughout the assembly process a lot of care had to be taken so as to avoid damaging of the permanent magnets, stator and its coils...

  19. Magnetic Gas Sensing Using a Dilute Magnetic Semiconductor. ...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Abstract: The authors report on a magnetic gas sensing methodology to detect hydrogen using the ferromagnetic properties of a nanoscale dilute magnetic semiconductor...

  20. Methods for magnetic resonance analysis using magic angle technique

    DOE Patents [OSTI]

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

    2011-11-22T23:59:59.000Z

    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.

  1. IEEE TRANSACTIONS ON MAGNETICS, VOL. 46, NO. 6, JUNE 2010 2187 Novel Solder-Magnetic Particle Composites and

    E-Print Network [OSTI]

    McHenry, Michael E.

    Terms--Electromagnetic induction heating, infrared imaging, magnetic nanoparticles, solder reflow. I University, Pittsburgh, PA 15213 USA Intel Corporation, Chandler, AZ 85226 USA Localized heating of solder reflow process, where the package is subjected to high temperatures. Localized heating is possible

  2. Superconducting Magnet Division

    E-Print Network [OSTI]

    Ohta, Shigemi

    Superconducting Magnet Division MAGNETIC DESIGN OF E-LENS SOLENOID AND CORRECTOR SYSTEM FOR RHIC* R.6 A gun collectors gun Combined Horizontal and Vertical Corrector Design Both types of dipole correctors. Gupta, M. Anerella, W. Fischer, G. Ganetis, X. Gu, A. Ghosh, A. Jain, P. Kovach, A. Marone, S. Plate, A

  3. Passive magnetic bearing configurations

    DOE Patents [OSTI]

    Post, Richard F. (Walnut Creek, CA)

    2011-01-25T23:59:59.000Z

    A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

  4. Active Magnetic Regenerator Experimental Optimization

    E-Print Network [OSTI]

    Victoria, University of

    the potential to create more efficient and compact refrigeration devices is an Active Magnetic Regenerative temperature refrigerators, as well as efficient gas liquefaction plants (AMRLs). Active Magnetic Regenerator Refrigeration exploits the magnetocaloric effect displayed by magnetic materials whereby a reversible

  5. Donna Rose Addis, TWRI, May 2004 1 ANALYSIS OF FUNCTIONAL MAGNETIC RESONANCE

    E-Print Network [OSTI]

    Addis, Donna Rose

    Donna Rose Addis, TWRI, May 2004 1 ANALYSIS OF FUNCTIONAL MAGNETIC RESONANCE IMAGING DATA USING SPM-ordinates (with signs reversed) into table as translations right, fwd and up · Check origin is at the AC · Select images (a_seg1.img, a_seg2 and brain_a.img) · Name output file (grey_clean) · Enter formula

  6. Toward magnetic field dissipation during the 23 July 2002 solar flare measured with Solar

    E-Print Network [OSTI]

    Zharkova, Valentina V.

    and Heliospheric Observatory/Michelson Doppler Imager (SOHO/MDI) and Reuven Ramaty High Energy Solar Spectroscopic and Heliospheric Observatory/Michelson Doppler Imager (SOHO/MDI) and Reuven Ramaty High Energy Solar Spectroscopic] It is widely accepted that the source of primary energy release in solar flares is associated with magnetic

  7. Morphology of the Small-Animal Lung Using Magnetic Resonance Microscopy

    E-Print Network [OSTI]

    Morphology of the Small-Animal Lung Using Magnetic Resonance Microscopy Laurence W. Hedlund and G motion control and animal support, the lungs of the live, small animal can be imaged. Although in vivo He, it is possible to image the tissue and gas compartments of the lung. This capability

  8. Femtosecond Transient Imaging

    E-Print Network [OSTI]

    Kirmani, Ahmed (Ghulam Ahmed)

    2010-01-01T23:59:59.000Z

    This thesis proposes a novel framework called transient imaging for image formation and scene understanding through impulse illumination and time images. Using time-of-flight cameras and multi-path analysis of global light ...

  9. Observation of Dirac Monopoles in a Synthetic Magnetic Field

    E-Print Network [OSTI]

    M. W. Ray; E. Ruokokoski; S. Kandel; M. Möttönen; D. S. Hall

    2014-08-13T23:59:59.000Z

    Magnetic monopoles --- particles that behave as isolated north or south magnetic poles --- have been the subject of speculation since the first detailed observations of magnetism several hundred years ago. Numerous theoretical investigations and hitherto unsuccessful experimental searches have followed Dirac's 1931 development of a theory of monopoles consistent with both quantum mechanics and the gauge invariance of the electromagnetic field. The existence of even a single Dirac magnetic monopole would have far-reaching physical consequences, most famously explaining the quantization of electric charge. Although analogues of magnetic monopoles have been found in exotic spin-ices and other systems, there has been no direct experimental observation of Dirac monopoles within a medium described by a quantum field, such as superfluid helium-3. Here we demonstrate the controlled creation of Dirac monopoles in the synthetic magnetic field produced by a spinor Bose-Einstein condensate. Monopoles are identified, in both experiments and matching numerical simulations, at the termini of vortex lines within the condensate. By directly imaging such a vortex line, the presence of a monopole may be discerned from the experimental data alone. These real-space images provide conclusive and long-awaited experimental evidence of the existence of Dirac monopoles. Our result provides an unprecedented opportunity to observe and manipulate these quantum-mechanical entities in a controlled environment.

  10. Plant root system analysis from MRI images Hannes Schulz1, Johannes A. Postma2, Dagmar van Dusschoten2,

    E-Print Network [OSTI]

    Behnke, Sven

    voxel to the base of the plant root, weighing the Euclidean distance measure by a multi-scale vesselness test this method using both virtually generated MRI images of Maize and real MRI images of Barley roots (Ferreira et al., 2010; Nakanishi et al., 2003; Pierret et al., 2003) and Nuclear Magnetic Resonance Imaging

  11. Review and comparison of magnet designs for magnetic refrigeration

    E-Print Network [OSTI]

    Bjørk, R; Smith, A; Pryds, N

    2014-01-01T23:59:59.000Z

    One of the key issues in magnetic refrigeration is generating the magnetic field that the magnetocaloric material must be subjected to. The magnet constitutes a major part of the expense of a complete magnetic refrigeration system and a large effort should therefore be invested in improving the magnet design. A detailed analysis of the efficiency of different published permanent magnet designs used in magnetic refrigeration applications is presented in this paper. Each design is analyzed based on the generated magnetic flux density, the volume of the region where this flux is generated and the amount of magnet material used. This is done by characterizing each design by a figure of merit magnet design efficiency parameter, $\\Lambda_\\mathrm{cool}$. The designs are then compared and the best design found. Finally recommendations for designing the ideal magnet design are presented based on the analysis of the reviewed designs.

  12. Condensed Matter and Magnet Science

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and HC) Suite of nondestructive pulsed magnets up to 100 tesla Thermoacoustics and fluid dynamics Transport, magnetism, and thermodynamic characterization at extreme conditions of...

  13. QUENCHES IN LARGE SUPERCONDUCTING MAGNETS

    E-Print Network [OSTI]

    Eberhard, P.H.

    2010-01-01T23:59:59.000Z

    QUENCHES IN LARGE SUPERCONDUCTING MAGNETS. P. H. Eberhard,Study of an Unprotected Superconducting Coil Going Normal,"Method for Testing Superconducting Magnets," LBL Physics

  14. Large Magnetization at Carbon Surfaces

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Large Magnetization at Carbon Surfaces Large Magnetization at Carbon Surfaces Print Wednesday, 31 August 2011 00:00 From organic matter to pencil lead, carbon is a versatile...

  15. Journal of Magnetism and Magnetic Materials ] (

    E-Print Network [OSTI]

    Schumann, Rolf

    width of internal field fluctuations. For the ``normal'' TR of the metallic magnets SmCo5; Sm2Co17 of the parameters for SmCo5 and barium ferrite. Susceptibility measurements with small alternating fields, carried out at different points of the TR curve, as well as repeating TR-experiments at SmCo5 demonstrate

  16. Imaging Sciences Workshop Proceedings

    SciTech Connect (OSTI)

    Candy, J.V.

    1996-11-21T23:59:59.000Z

    This report contains the proceedings of the Imaging Sciences Workshop sponsored by C.A.S.LS., the Center for Advanced Signal & Image Sciences. The Center, established primarily to provide a forum where researchers can freely exchange ideas on the signal and image sciences in a comfortable intellectual environment, has grown over the last two years with the opening of a Reference Library (located in Building 272). The Technical Program for the 1996 Workshop include a variety of efforts in the Imaging Sciences including applications in the Microwave Imaging, highlighted by the Micro-Impulse Radar (MIR) system invented at LLNL, as well as other applications in this area. Special sessions organized by various individuals in Speech, Acoustic Ocean Imaging, Radar Ocean Imaging, Ultrasonic Imaging, and Optical Imaging discuss various applica- tions of real world problems. For the more theoretical, sessions on Imaging Algorithms and Computed Tomography were organized as well as for the more pragmatic featuring a session on Imaging Systems.

  17. Fourier-based magnetic induction tomography for mapping resistivity

    SciTech Connect (OSTI)

    Puwal, Steffan; Roth, Bradley J. [Department of Physics, Oakland University, Rochester, Michigan 48309 (United States)

    2011-01-01T23:59:59.000Z

    Magnetic induction tomography is used as an experimental tool for mapping the passive electromagnetic properties of conductors, with the potential for imaging biological tissues. Our numerical approach to solving the inverse problem is to obtain a Fourier expansion of the resistivity and the stream functions of the magnetic fields and eddy current density. Thus, we are able to solve the inverse problem of determining the resistivity from the applied and measured magnetic fields for a two-dimensional conducting plane. When we add noise to the measured magnetic field, we find the fidelity of the measured to the true resistivity is quite robust for increasing levels of noise and increasing distances of the applied and measured field coils from the conducting plane, when properly filtered. We conclude that Fourier methods provide a reliable alternative for solving the inverse problem.

  18. Magnetic Field Geometry in "Red" and "Blue" BL Lacs

    E-Print Network [OSTI]

    P. Kharb; D. C. Gabuzda; P. Shastri

    2003-01-06T23:59:59.000Z

    We compare the systematics of the magnetic field geometry in the "red" low-energy peaked BL Lacs (LBLs) and "blue" high-energy peaked BL Lacs (HBLs) using VLBI polarimetric images. The LBLs are primarily "radio--selected" BL Lacs and the HBLs are primarily "X-ray selected". In contrast to the LBLs, which show predominantly transverse jet magnetic fields, the HBLs show predominantly longitudinal fields. Thus, while the SED peaks of core-dominated quasars, LBLs and HBLs form a sequence of increasing frequency, the magnetic field geometry does not follow an analogous sequence. We briefly investigate possible connections between the observed parsec-scale magnetic field structures and circular polarization measurements in the literature on various spatial scales.

  19. Dynamics of molecular superrotors in external magnetic field

    E-Print Network [OSTI]

    Korobenko, Aleksey

    2015-01-01T23:59:59.000Z

    We excite diatomic oxygen and nitrogen to high rotational states with an optical centrifuge and study their dynamics in external magnetic field. Ion imaging is employed to directly visualize, and follow in time, the rotation plane of molecular superrotors. The two different mechanisms of interaction between the magnetic field and the molecular angular momentum in paramagnetic oxygen and non-magnetic nitrogen lead to the qualitatively different behaviour. In nitrogen, we observe the precession of the molecular angular momentum around the field vector. In oxygen, strong spin-rotation coupling results in faster and richer dynamics, encompassing the splitting of the rotation plane in three separate components. As the centrifuged molecules evolve with no significant dispersion of the molecular wave function, the observed magnetic interaction presents an efficient mechanism for controlling the plane of molecular rotation.

  20. Permanent magnet energy conversion machine with magnet mounting arrangement

    DOE Patents [OSTI]

    Hsu, John S. (Oak Ridge, TN); Adams, Donald J. (Knoxville, TN)

    1999-01-01T23:59:59.000Z

    A hybrid permanent magnet dc motor includes three sets of permanent magnets supported by the rotor and three sets of corresponding stators fastened to the surrounding frame. One set of magnets operates across a radial gap with a surrounding radial gap stator, and the other two sets of magnets operate off the respective ends of the rotor across respective axial gaps.

  1. Moment free toroidal magnet

    DOE Patents [OSTI]

    Bonanos, Peter (East Brunswick, NJ)

    1983-01-01T23:59:59.000Z

    A toroidal magnet for confining a high magnetic field for use in fusion reactor research and nuclear particle detection. The magnet includes a series of conductor elements arranged about and fixed at its small major radius portion to the outer surface of a central cylindrical support each conductor element having a geometry such as to maintain the conductor elements in pure tension when a high current flows therein, and a support assembly which redistributes all or part of the tension which would otherwise arise in the small major radius portion of each coil element to the large major radius portion thereof.

  2. Relation between photospheric flow fields and the magnetic field distribution on the solar surface

    SciTech Connect (OSTI)

    Simon, G.W.; Title, A.M.; Topka, K.P.; Tarbell, T.D.; Shine, R.A.

    1988-04-01T23:59:59.000Z

    Using the technique of local correlation tracking on a 28 minute time sequence of white-light images of solar granulation, the horizontal flow field on the solar surface is measured. The time series was obtained by the Solar Optical Universal Polarimeter (SOUP) on Spacelab 2 (Space Shuttle flight 51-F) and is free from atmospheric blurring and distortion. The SOUP flow fields have been compared with carefully aligned magnetograms taken over a nine hour period at the Big Bear Solar Observatory before, during, and after the SOUP images. The flow field and the magnetic field agree in considerable detail: vectors which define the flow of the white-light intensity pattern (granulation) point toward magnetic field regions, magnetic fields surround flow cells, and magnetic features move along the flow arrows. The projected locations of free particles (corks) in the measured flow field congregate at the same locations where the magnetic field is observed. 31 references.

  3. Observation of the structural phase transition in manganite films by magneto-optical imaging.

    SciTech Connect (OSTI)

    Crabtree, G. W.; Lin, Y.; Miller, D. J.; Nikitenko, V. I.; Vlasko-Vlasov, V. K.; Welp, U.

    1999-08-31T23:59:59.000Z

    A high-resolution magneto-optical imaging technique is used to reveal the formation of twins occurring during a martensitic phase transition at {approximately}105K in LCMO films grown on STO substrates. The magnetic contrast arises due to the magneto-elastic tilts of the Mn - magnetic moments in the twins. Different magnetic structures are found in LCMO films grown on MgO, NGO, and LAO substrates showing the importance of the substrate material for the manganite film properties.

  4. Instabilities and transport in magnetized plasmas

    E-Print Network [OSTI]

    Rosin, Mark

    2011-02-08T23:59:59.000Z

    . The ensuing flows and tem- perature profiles are anisotropic with respect to the direction of the magnetic field, and lead to highly filamentary structures. Left Panel: X-ray emission im- age of solar coronal loops taken by the Transition Region and Coronal... Explorer (TRACE) (Reale & Peres, 2000; Reale et al., 2000; TRACE, 2000). Right Panel: D? emission images (visible light) from Edge Localised Modes (ELMS) on the Mega Ampere Spherical Tokomak (MAST) (Kirk et al., 2005; Dudson et al., 2008). in an asymptotic...

  5. Seismic Imaging and Monitoring

    SciTech Connect (OSTI)

    Huang, Lianjie [Los Alamos National Laboratory

    2012-07-09T23:59:59.000Z

    I give an overview of LANL's capability in seismic imaging and monitoring. I present some seismic imaging and monitoring results, including imaging of complex structures, subsalt imaging of Gulf of Mexico, fault/fracture zone imaging for geothermal exploration at the Jemez pueblo, time-lapse imaging of a walkway vertical seismic profiling data for monitoring CO{sub 2} inject at SACROC, and microseismic event locations for monitoring CO{sub 2} injection at Aneth. These examples demonstrate LANL's high-resolution and high-fidelity seismic imaging and monitoring capabilities.

  6. Modular tokamak magnetic system

    DOE Patents [OSTI]

    Yang, Tien-Fang (Wayland, MA)

    1988-01-01T23:59:59.000Z

    A modular tokamak system comprised of a plurality of interlocking moldules. Each module is comprised of a vacuum vessel section, a toroidal field coil, moldular saddle coils which generate a poloidal magnetic field and ohmic heating coils.

  7. Geometrically frustrated quantum magnets

    E-Print Network [OSTI]

    Nikolić , Predrag, 1974-

    2004-01-01T23:59:59.000Z

    (cont.) more general lessons on frustrated quantum magnetism. At the end, we demonstrate some new mathematical tools on two other frustrated two-dimensional systems, and summarize our conclusions, with an outlook to remaining ...

  8. Ultrafast Magnetic Light

    E-Print Network [OSTI]

    Makarov, Sergey V; Krasnok, Alexander E; Belov, Pavel A

    2015-01-01T23:59:59.000Z

    We propose a novel concept for efficient dynamic tuning of optical properties of a high refractive index subwavelength nanoparticle with a magnetic Mie-type resonance by means of femtosecond laser radiation. This concept is based on ultrafast generation of electron-hole plasma within such nanoparticle, drastically changing its transient dielectric permittivity. This allows to manipulate by both electric and magnetic nanoparticle responses, resulting in dramatic changes of its extinction cross section and scattering diagram. Specifically, we demonstrate the effect of ultrafast switching-on a Huygens source in the vicinity of the magnetic dipole resonance. This approach enables to design ultrafast and compact optical switchers and modulators based on the "ultrafast magnetic light" concept.

  9. Magnetic gripper device

    DOE Patents [OSTI]

    Meyer, Ross E. (Los Alamos, NM)

    1993-01-01T23:59:59.000Z

    A climbing apparatus is provided for climbing ferromagnetic surfaces, such as storage tanks and steel frame structures. A magnet assembly is rotatably mounted in a frame assembly. The frame assembly provides a pair of cam surfaces having different dimensions so that, when the frame is rotated, the cam surfaces contact the ferromagnetic surface to separate the magnet assembly from the surface. The different cam dimensions enable one side of the magnet at a time to be detached from the surface to reduce the effort needed to disengage the climbing apparatus. The cam surface also provides for smoothly attaching the apparatus. A hardened dowel pin is also attached to the frame and the pointed end of the dowel engages the surface when the magnet is attached to the surface to prevent downward sliding movement of the assembly under the weight of the user.

  10. Magnetic gripper device

    DOE Patents [OSTI]

    Meyer, R.E.

    1993-03-09T23:59:59.000Z

    A climbing apparatus is provided for climbing ferromagnetic surfaces, such as storage tanks and steel frame structures. A magnet assembly is rotatably mounted in a frame assembly. The frame assembly provides a pair of cam surfaces having different dimensions so that, when the frame is rotated, the cam surfaces contact the ferromagnetic surface to separate the magnet assembly from the surface. The different cam dimensions enable one side of the magnet at a time to be detached from the surface to reduce the effort needed to disengage the climbing apparatus. The cam surface also provides for smoothly attaching the apparatus. A hardened dowel pin is also attached to the frame and the pointed end of the dowel engages the surface when the magnet is attached to the surface to prevent downward sliding movement of the assembly under the weight of the user.

  11. Magnetic susceptibility, magnetization, magnetic moment and characterization of Carancas meteorite

    E-Print Network [OSTI]

    Rosales, Domingo

    2015-01-01T23:59:59.000Z

    On September, 15th, 2007, in the community of Carancas (Puno, Peru) a stony meteorite formed a crater explosive type with a mean diameter of 13.5 m. some samples meteorite fragments were collected. The petrologic analysis performed corresponds to a meteorite ordinary chondrite H 4-5. In this paper we have analyzed the magnetic properties of a meteorite fragment with a proton magnetometer. Also in order to have a complete characterization of the Carancas meteorite and its crater, from several papers, articles and reports, we have made a compilation of the most important characteristics and properties of this meteorite.

  12. Permanent Magnet Ecr Plasma Source With Magnetic Field Optimization

    DOE Patents [OSTI]

    Doughty, Frank C. (Plano, TX); Spencer, John E. (Plano, TX)

    2000-12-19T23:59:59.000Z

    In a plasma-producing device, an optimized magnet field for electron cyclotron resonance plasma generation is provided by a shaped pole piece. The shaped pole piece adjusts spacing between the magnet and the resonance zone, creates a convex or concave resonance zone, and decreases stray fields between the resonance zone and the workpiece. For a cylindrical permanent magnet, the pole piece includes a disk adjacent the magnet together with an annular cylindrical sidewall structure axially aligned with the magnet and extending from the base around the permanent magnet. The pole piece directs magnetic field lines into the resonance zone, moving the resonance zone further from the face of the magnet. Additional permanent magnets or magnet arrays may be utilized to control field contours on a local scale. Rather than a permeable material, the sidewall structure may be composed of an annular cylindrical magnetic material having a polarity opposite that of the permanent magnet, creating convex regions in the resonance zone. An annular disk-shaped recurve section at the end of the sidewall structure forms magnetic mirrors keeping the plasma off the pole piece. A recurve section composed of magnetic material having a radial polarity forms convex regions and/or magnetic mirrors within the resonance zone.

  13. Magnetic coupling device

    DOE Patents [OSTI]

    Nance, Thomas A. (Aiken, SC)

    2009-08-18T23:59:59.000Z

    A quick connect/disconnect coupling apparatus is provided in which a base member is engaged by a locking housing through a series of interengagement pins. The pins maintain the shaft in a locked position. Upon exposure to an appropriately positioned magnetic field, pins are removed a sufficient distance such that the shaft may be withdrawn from the locking housing. The ability to lock and unlock the connector assembly requires no additional tools or parts apart from a magnetic key.

  14. Magnetic fluorescent lamp

    DOE Patents [OSTI]

    Berman, S.M.; Richardson R.W.

    1983-12-29T23:59:59.000Z

    The radiant emission of a mercury-argon discharge in a fluorescent lamp assembly is enhanced by providing means for establishing a magnetic field with lines of force along the path of electron flow through the bulb of the lamp assembly, to provide Zeeman splitting of the ultraviolet spectral line. Optimum results are obtained when the magnetic field strength causes a Zeeman splitting of approximately 1.7 times the thermal line width.

  15. Freely oriented portable superconducting magnet

    DOE Patents [OSTI]

    Schmierer, Eric N. (Los Alamos, NM); Prenger, F. Coyne (Los Alamos, NM); Hill, Dallas D. (Los Alamos, NM)

    2010-01-12T23:59:59.000Z

    A freely oriented portable superconducting magnet is disclosed. Coolant is supplied to the superconducting magnet from a repository separate from the magnet, enabling portability of the magnet. A plurality of support assemblies structurally anchor and thermally isolate the magnet within a thermal shield. A plurality of support assemblies structurally anchor and thermally isolate the thermal shield within a vacuum vessel. The support assemblies restrain movement of the magnet resulting from energizing and cooldown, as well as from changes in orientation, enabling the magnet to be freely orientable.

  16. A numerical approach : broadband technologies for efficient Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Mitsouras, Dimitrios, 1976-

    2004-01-01T23:59:59.000Z

    (cont.) independent receiver coils in parallel or time-axis compression, can be cast as complementary to broadband MRI encoding. This affords broadband non-Fourier MRI with time efficiencies over current fast MRI methods. ...

  17. Bayesian Experimental Design of Magnetic Resonance Imaging Sequences

    E-Print Network [OSTI]

    Seeger, Matthias

    Nickisch, Rolf Pohmann and Bernhard Sch¨olkopf Max Planck Institute for Biological Cybernetics research of the brain. Without applying any harmful ioniz- ing radiation, this technique stands out by its

  18. Narrowband and x-Space Magnetic Particle Imaging

    E-Print Network [OSTI]

    Goodwill, Patrick

    2010-01-01T23:59:59.000Z

    as nonlinear mixers in a confluence of static and dynamicas nonlinear mixers in a confluence of static and dynamic

  19. Magnetic metallic multilayers

    SciTech Connect (OSTI)

    Hood, R.Q.

    1994-04-01T23:59:59.000Z

    Utilizing self-consistent Hartree-Fock calculations, several aspects of multilayers and interfaces are explored: enhancement and reduction of the local magnetic moments, magnetic coupling at the interfaces, magnetic arrangements within each film and among non-neighboring films, global symmetry of the systems, frustration, orientation of the various moments with respect to an outside applied field, and magnetic-field induced transitions. Magnetoresistance of ferromagnetic-normal-metal multilayers is found by solving the Boltzmann equation. Results explain the giant negative magnetoresistance encountered in these systems when an initial antiparallel arrangement is changed into a parallel configuration by an external magnetic field. The calculation depends on (1) geometric parameters (thicknesses of layers), (2) intrinsic metal parameters (number of conduction electrons, magnetization, and effective masses in layers), (3) bulk sample properties (conductivity relaxation times), (4) interface scattering properties (diffuse scattering versus potential scattering at the interfaces, and (5) outer surface scattering properties (specular versus diffuse surface scattering). It is found that a large negative magnetoresistance requires considerable asymmetry in interface scattering for the two spin orientations. Features of the interfaces that may produce an asymmetrical spin-dependent scattering are studied: varying interfacial geometric random roughness with no lateral coherence, correlated (quasi-periodic) roughness, and varying chemical composition of the interfaces. The interplay between these aspects of the interfaces may enhance or suppress the magnetoresistance, depending on whether it increases or decreases the asymmetry in the spin-dependent scattering of the conduction electrons.

  20. AN APPROACH FOR INTERSUBJECT ANALYSIS OF 3D BRAIN IMAGES BASED ON CONFORMAL GEOMETRY

    E-Print Network [OSTI]

    Hua, Jing

    ABSTRACT Recent advances in imaging technologies, such as Magnetic Resonance Imaging (MRI), Positron technologies have accelerated brain research in many aspects [10, 12, 13]. In order to enable comparison that it minimizes the landmark mismatch energy [4] and Wang et al. introduced the application of compound energy

  1. Roadmap: Radiologic Imaging Sciences -Computed Tomography (with certification and ATS Radiologic Technology) -

    E-Print Network [OSTI]

    Sheridan, Scott

    Roadmap: Radiologic Imaging Sciences - Computed Tomography (with certification and ATS Radiologic 34084 Computed Tomography and Magnetic Resonance Imaging Sectional Anatomy I 2 C RIS 44021 Patient Management in Computed Tomography 2 C RIS 44025 Computed Tomography Clinical Education I 3 C RIS 44030

  2. Roadmap: Radiologic Imaging Sciences -Computed Tomography (with certification and ATS Radiologic Technology) -

    E-Print Network [OSTI]

    Sheridan, Scott

    Roadmap: Radiologic Imaging Sciences - Computed Tomography (with certification and ATS Radiologic 34084 Computed Tomography and Magnetic Resonance Imaging Sectional Anatomy I 2 C RIS 44021 Patient Management in Computed Tomography (CT) 2 C RIS 44025 Computed Tomography (CT) Clinical Education I 3 C

  3. 3D Harmonic Mapping and Tetrahedral Meshing of Brain Imaging Data

    E-Print Network [OSTI]

    Thompson, Paul

    3D Harmonic Mapping and Tetrahedral Meshing of Brain Imaging Data Yalin Wang1 , Xianfeng Gu2 , Paul algorithm finds a harmonic map from a 3-manifold to a 3D solid sphere and the second is a novel sphere of magnetic resonance images (MRI). A heat flow method is used to solve the volumetric harmonic mapping

  4. New Frontiers in Solar Physics: Broadband Imaging Spectroscopy with the

    E-Print Network [OSTI]

    , the solar panel of the AASC recommended an integrated suite of instrumentation designed to meetNew Frontiers in Solar Physics: Broadband Imaging Spectroscopy with the Frequency Agile Solar and other astrophysical objects and processes. Outstanding problems in solar physics include the magnetic

  5. Imaging Agents DOI: 10.1002/anie.201301135

    E-Print Network [OSTI]

    Gao, Jinming

    Takahashi, A. Dean Sherry, and Jinming Gao* Magnetic resonance imaging (MRI) is a powerful non- invasive a "reverse" pH gradient across the cell membrane is observed in cancer cells compared to normal cells.[11 19 F signal. b) Structural formula of three representative diblock copolymers containing different p

  6. Current-driven ion-acoustic and potential-relaxation instabilities excited in plasma plume during electron beam welding

    SciTech Connect (OSTI)

    Trushnikov, D. N., E-mail: trdimitr@yandex.ru [The department for Applied Physics, Perm National Research Polytechnic University, Perm, 614990 (Russian Federation); Mladenov, G. M., E-mail: gmmladenov@abv.bg; Koleva, E. G., E-mail: eligeorg@abv.bg [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Shose, 1784, Sofia (Bulgaria); Technology Centre of Electron Beam and Plasma Technologies and Techniques, 68-70 Vrania, ap.10, Banishora,1309, Sofia (Bulgaria); Belenkiy, V. Ya., E-mail: mtf@pstu.ru; Varushkin, S. V., E-mail: stepan.varushkin@mail.ru [The department for Welding Production and Technology of Constructional Materials, Perm National Research Polytechnic University, Perm, 614990 (Russian Federation)

    2014-04-15T23:59:59.000Z

    Many papers have sought correlations between the parameters of secondary particles generated above the beam/work piece interaction zone, dynamics of processes in the keyhole, and technological processes. Low- and high-frequency oscillations of the current, collected by plasma have been observed above the welding zone during electron beam welding. Low-frequency oscillations of secondary signals are related to capillary instabilities of the keyhole, however; the physical mechanisms responsible for the high-frequency oscillations (>10 kHz) of the collected current are not fully understood. This paper shows that peak frequencies in the spectra of the collected high-frequency signal are dependent on the reciprocal distance between the welding zone and collector electrode. From the relationship between current harmonics frequency and distance of the collector/welding zone, it can be estimated that the draft velocity of electrons or phase velocity of excited waves is about 1600 m/s. The dispersion relation with the properties of ion-acoustic waves is related to electron temperature 10 000 K, ion temperature 2 400 K and plasma density 10{sup 16} m{sup ?3}, which is analogues to the parameters of potential-relaxation instabilities, observed in similar conditions. The estimated critical density of the transported current for creating the anomalous resistance state of plasma is of the order of 3 A·m{sup ?2}, i.e. 8 mA for a 3–10 cm{sup 2} collector electrode. Thus, it is assumed that the observed high-frequency oscillations of the current collected by the positive collector electrode are caused by relaxation processes in the plasma plume above the welding zone, and not a direct demonstration of oscillations in the keyhole.

  7. Magnetic monopole and the nature of the static magnetic field

    E-Print Network [OSTI]

    Xiuqing Huang

    2008-12-10T23:59:59.000Z

    We investigate the factuality of the hypothetical magnetic monopole and the nature of the static magnetic field. It is shown from many aspects that the concept of the massive magnetic monopoles clearly is physically untrue. We argue that the static magnetic field of a bar magnet, in fact, is the static electric field of the periodically quasi-one-dimensional electric-dipole superlattice, which can be well established in some transition metals with the localized d-electron. This research may shed light on the perfect unification of magnetic and electrical phenomena.

  8. Ultra-high-resolution Observations of MHD Waves in Photospheric Magnetic Structures

    E-Print Network [OSTI]

    Jess, David B

    2015-01-01T23:59:59.000Z

    Here we review the recent progress made in the detection, examination, characterisation and interpretation of oscillations manifesting in small-scale magnetic elements in the solar photosphere. This region of the Sun's atmosphere is especially dynamic, and importantly, permeated with an abundance of magnetic field concentrations. Such magnetic features can span diameters of hundreds to many tens of thousands of km, and are thus commonly referred to as the `building blocks' of the magnetic solar atmosphere. However, it is the smallest magnetic elements that have risen to the forefront of solar physics research in recent years. Structures, which include magnetic bright points, are often at the diffraction limit of even the largest of solar telescopes. Importantly, it is the improvements in facilities, instrumentation, imaging techniques and processing algorithms during recent years that have allowed researchers to examine the motions, dynamics and evolution of such features on the smallest spatial and temporal ...

  9. Active magnetic regenerator

    DOE Patents [OSTI]

    Barclay, J.A.; Steyert, W.A.

    1981-01-27T23:59:59.000Z

    An apparatus and method for refrigeration are disclosed which provides efficient refrigeration over temperature ranges in excess of 20/sup 0/C and which requires no maintenance and is, therefore, usable on an unmanned satellite. The apparatus comprises a superconducting magnet which may be solenoidal. A piston comprising a substance such as a rare earth substance which is maintained near its Curie temperature reciprocates through the bore of the solenoidal magnet. A magnetic drive rod is connected to the piston and appropriate heat sinks are connected thereto. The piston is driven by a suitable mechanical drive such as an electric motor and cam. In practicing the invention, the body of the piston is magnetized and demagnetized as it moves through the magnetic field of the solenoid to approximate any of the following cycles or a condition thereof as well as, potentially, other cycles: Brayton, Carnot, Ericsson, and Stirling. Advantages of the present invention include: that refrigeration can be accomplished over at least a 20/sup 0/C scale at superconducting temperatures as well as at more conventional temperatures; very high efficiency, high reliability, and small size. (LCL)

  10. Frustrated Magnetism in Low-Dimensional Lattices

    E-Print Network [OSTI]

    Tovar, Mayra

    2011-01-01T23:59:59.000Z

    and C. Baines. Quantum magnetism in the paratacamite family:14] Stephen Blundell. Magnetism in Condensed Matter. OxfordElectrons and Quantum Magnetism. Graduate Texts in Con-

  11. Magnetic spectroscopy and microscopy of functional materials

    E-Print Network [OSTI]

    Jenkins, C.A.

    2012-01-01T23:59:59.000Z

    transitions for magnetic refrigeration. Appl Phys Lett, 97(these e?ects in magnetic refrigeration and actuation makesheat ?ow with the goal of magnetic refrigeration (adiabatic

  12. Superconducting Magnet Technology for Future Hadron Colliders

    E-Print Network [OSTI]

    Scanlan, R.M.

    2011-01-01T23:59:59.000Z

    I. Superconducting Magnet Technology for Future Hadl"On1994. M.N. Wilson, Superconducting Magnets (Clarendon Press,The application of superconducting magnets to large-scale

  13. SKA Deep Polarization and Cosmic Magnetism

    E-Print Network [OSTI]

    Taylor, A R; Akahori, Takuya; Beck, Rainer; Gaensler, Bryan; Heald, George; Johnston-Hollitt, Melanie; Langer, Mathieu; Rudnick, Lawrence; Ryu, Dongsu; Scaife, Anna; Schleicher, Dominik; Stil, Jeroen

    2015-01-01T23:59:59.000Z

    Deep surveys with the SKA1-MID array offer for the first time the opportunity to systematically explore the polarization properties of the microJy source population. Our knowledge of the polarized sky approaching these levels is still very limited. In total intensity the population will be dominated by star-forming and normal galaxies to intermediate redshifts ($z \\sim1-2$), and low-luminosity AGN to high redshift. The polarized emission from these objects is a powerful probe of their intrinsic magnetic fields and of their magnetic environments. For redshift of order 1 and above the broad bandwidth of the mid-bands span the Faraday thick and thin regimes allowing study of the intrinsic polarization properties of these objects as well as depolarization from embedded and foreground plasmas. The deep field polarization images will provide Rotation Measures data with very high solid angle density allowing a sensitive statistical analysis of the angular variation of RM on critical arc-minute scales from a magnetic...

  14. Superconducting magnetic coil

    DOE Patents [OSTI]

    Aized, D.; Schwall, R.E.

    1999-06-22T23:59:59.000Z

    A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil. 15 figs.

  15. Superconducting magnetic coil

    DOE Patents [OSTI]

    Aized, Dawood (Marlboro, MA); Schwall, Robert E. (Northborough, MA)

    1999-06-22T23:59:59.000Z

    A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

  16. Magnetic resonance studies of cement based materials in inhomogeneous magnetic fields

    SciTech Connect (OSTI)

    Boguszynska, Joanna [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, Poznan (Poland); Brown, Marc C.A. [School of Physical Sciences, University of Kent, Canterbury, Kent, CT2 7NR (United Kingdom); McDonald, Peter J. [School of Electronics and Physical Sciences, University of Surrey, Surrey, GU2 7XH (United Kingdom)]. E-mail: p.mcdonald@surrey.ac.uk; Mitchell, Jonathan [School of Electronics and Physical Sciences, University of Surrey, Surrey, GU2 7XH (United Kingdom); Mulheron, Mike [School of Engineering, University of Surrey, Surrey, GU2 7XH (United Kingdom); Tritt-Goc, Jadwiga [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, Poznan (Poland); Verganelakis, Dimitris A. [Department of Chemical Engineering, University of Cambridge, Cambridge, CB2 3RA (United Kingdom)

    2005-10-01T23:59:59.000Z

    Single-sided magnets give hope that Nuclear Magnetic Resonance (NMR) might in future be used for in situ characterisation of hydration and water transport in the surface layers of concrete slabs. Towards that end, a portable NMR-MOUSE (MObile Universal Surface Explorer) has been used to follow the hydration of gypsum based plaster, a Portland cement paste and concrete mortar. The results compare favourably to those obtained using a standard laboratory bench-top spectrometer. Further, stray field imaging (STRAFI) based methods have been used with embedded NMR detector coils to study water transport across a mortar/topping interface. The measured signal amplitudes are found to correlate with varying sample conditions.

  17. Magnetic fluid flow phenomena in DC and rotating magnetic fields

    E-Print Network [OSTI]

    Rhodes, Scott E. (Scott Edward), 1981-

    2004-01-01T23:59:59.000Z

    An investigation of magnetic fluid experiments and analysis is presented in three parts: a study of magnetic field induced torques in magnetorheological fluids, a characterization and quantitative measurement of properties ...

  18. Magnetic catalysis and inverse magnetic catalysis in QCD

    E-Print Network [OSTI]

    Niklas Mueller; Jan M. Pawlowski

    2015-02-27T23:59:59.000Z

    We investigate the effects of strong magnetic fields on the QCD phase structure at vanishing density by solving the gluon and quark gap equations, and by studying the dynamics of the quark scattering with the four-fermi coupling. The chiral crossover temperature as well as the chiral condensate are computed. For asymptotically large magnetic fields we find magnetic catalysis, while we find inverse magnetic catalysis for intermediate magnetic fields. Moreover, for large magnetic fields the chiral phase transition for massless quarks turns into a crossover. The underlying mechanisms are then investigated analytically within a few simplifications of the full numerical analysis. We find that a combination of gluon screening effects and the weakening of the strong coupling is responsible for the phenomenon of inverse catalysis. In turn, the magnetic catalysis at large magnetic field is already indicated by simple arguments based on dimensionality.

  19. Magnetic nanowire based high resolution magnetic force microscope probes

    E-Print Network [OSTI]

    Qin, Lu-Chang

    -resolution magnetic force microscope probes using preformed magnetic nanowires. Nickel and cobalt nanowires produced by electrodeposition were directly assembled onto the tip of a commercial atomic force microscope cantilever

  20. User Science Images

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Image: OBrianImageBig.png | png | 5 MB SlavaFull.png FES: Small Scale Experimental Plasma Research October 21, 2010 | Author(s): Vyacheslav Lukin (NRL) | Category: Fusion Energy |...

  1. Imaging in radiotherapy

    SciTech Connect (OSTI)

    Taylor, J.

    1987-01-01T23:59:59.000Z

    The text contains details of recording media, image quality, sensitometry, processing and equipment used in radiotherapy for imaging. It reflects part of the syllabus for the College of Radiographers.

  2. Magnetic Field Measurement System

    SciTech Connect (OSTI)

    Kulesza, Joe; Johnson, Eric; Lyndaker, Aaron; Deyhim, Alex; Waterman, Dave; Blomqvist, K. Ingvar [Advanced Design Consulting USA, 126 Ridge Road, P.O. Box 187, Lansing, NY 14882 (United States); Dunn, Jonathan Hunter [MAX-lab, SE-221 00 Lund (Sweden)

    2007-01-19T23:59:59.000Z

    A magnetic field measurement system was designed, built and installed at MAX Lab, Sweden for the purpose of characterizing the magnetic field produced by Insertion Devices (see Figure 1). The measurement system consists of a large granite beam roughly 2 feet square and 14 feet long that has been polished beyond laboratory grade for flatness and straightness. The granite precision coupled with the design of the carriage yielded minimum position deviations as measured at the probe tip. The Hall probe data collection and compensation technique allows exceptional resolution and range while taking data on the fly to programmable sample spacing. Additional flip coil provides field integral data.

  3. Cool Magnetic Molecules

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration would likeConstitution AndControllingCool Magnetic Molecules Cool Magnetic

  4. Zoomed Functional Imaging in the Human Brain at 7 Tesla with Simultaneous High Spatial and High Temporal Resolution

    E-Print Network [OSTI]

    Zoomed Functional Imaging in the Human Brain at 7 Tesla with Simultaneous High Spatial and High and is mainly limited by sensitivity. Here, signal-to-noise gains at high magnetic fields (7 Tesla

  5. Consumers' Image of Broilers.

    E-Print Network [OSTI]

    Courtenay, Henry V.; Branson, Robert E.

    1962-01-01T23:59:59.000Z

    which they feel the product possesses. This research was designed to determine consumers' favorable and unfavorable images as to broilers, both in making purchases in stores and in serving them as a meat dish. These images, summarized briefly here... count. The Preparation and Cooking Image: The h0u.l wife's image of broilers focuses on one metliotl- frying. The major deterrent to preparing othci dishes was that these are either too difficult or canno* be prepared satisfactorily...

  6. Imaging with Scattered Neutrons

    E-Print Network [OSTI]

    H. Ballhausen; H. Abele; R. Gaehler; M. Trapp; A. Van Overberghe

    2006-10-30T23:59:59.000Z

    We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-resolution images by scattered neutron radiography and tomography are presented.

  7. Human Functional Brain Imaging

    E-Print Network [OSTI]

    Rambaut, Andrew

    Human Functional Brain Imaging 1990­2009 September 2011 Portfolio Review #12;2 | Portfolio Review: Human Functional Brain ImagingThe Wellcome Trust is a charity registered in England and Wales, no's role in supporting human functional brain imaging and have informed `our' speculations for the future

  8. Human Functional Brain Imaging

    E-Print Network [OSTI]

    Rambaut, Andrew

    Human Functional Brain Imaging 1990­2009 September 2011 Portfolio Review Summary Brain Imaging #12 Dale ­ one of our first Trustees. Understanding the brain remains one of our key strategic aims today three-fold: · to identify the key landmarks and influences on the human functional brain imaging

  9. Medical imaging systems

    DOE Patents [OSTI]

    Frangioni, John V

    2013-06-25T23:59:59.000Z

    A medical imaging system provides simultaneous rendering of visible light and diagnostic or functional images. The system may be portable, and may include adapters for connecting various light sources and cameras in open surgical environments or laparascopic or endoscopic environments. A user interface provides control over the functionality of the integrated imaging system. In one embodiment, the system provides a tool for surgical pathology.

  10. Magnetic nanoworms Systematic Surface Engineering of Magnetic Nanoworms

    E-Print Network [OSTI]

    Bhatia, Sangeeta

    Magnetic nanoworms Systematic Surface Engineering of Magnetic Nanoworms for in vivo Tumor Targeting and Engineering Program Department of Chemistry and Biochemistry University of California, San Diego 9500 Gilman magnetic materials nanoworms peptides tumor targeting 694 ß 2009 Wiley-VCH Verlag GmbH & Co. KGa

  11. Magnetic Coordinates for Systems with Imperfect Magnetic Surfaces

    E-Print Network [OSTI]

    Dewar, Robert L.

    Magnetic Coordinates for Systems with Imperfect Magnetic Surfaces R. L. Dewar and S. R. Hudson & Engineering, The Australian National University, Canberra, A.C.T. 0200, Australia e-mail: robert-orbits, and the surfaces are formed from a continuous one-parameter family of such orbits. Magnetic field-line flow

  12. Automation in image cytometry : continuous HCS and kinetic image cytometry

    E-Print Network [OSTI]

    Charlot, David J.

    2012-01-01T23:59:59.000Z

    OF CALIFORNIA, SAN DIEGO Automation in Image Cytometry:xiv Abstract of Dissertation Automation in Image Cytometry:

  13. Ultra-low field nuclear magnetic resonance and magnetic resonance imaging to discriminate and identify materials

    SciTech Connect (OSTI)

    Matlashov, Andrei Nikolaevich; Urbaitis, Algis V.; Savukov, Igor Mykhaylovich; Espy, Michelle A.; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry

    2013-03-05T23:59:59.000Z

    Method comprising obtaining an NMR measurement from a sample wherein an ultra-low field NMR system probes the sample and produces the NMR measurement and wherein a sampling temperature, prepolarizing field, and measurement field are known; detecting the NMR measurement by means of inductive coils; analyzing the NMR measurement to obtain at least one measurement feature wherein the measurement feature comprises T1, T2, T1.rho., or the frequency dependence thereof; and, searching for the at least one measurement feature within a database comprising NMR reference data for at least one material to determine if the sample comprises a material of interest.

  14. Stellar magnetic field measurements Zeeman-Doppler imaging and magnetic-flux

    E-Print Network [OSTI]

    and this experience will be incorporated in the use of the PEPSI polarimeters at the 2x8.4-m LBT. Temperature

  15. Magnetic refrigeration apparatus and method

    DOE Patents [OSTI]

    Barclay, John A. (Los Alamos, NM); Overton, Jr., William C. (Los Alamos, NM); Stewart, Walter F. (Los Alamos, NM)

    1984-01-01T23:59:59.000Z

    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.

  16. Large Magnetization at Carbon Surfaces

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Large Magnetization at Carbon Surfaces Print From organic matter to pencil lead, carbon is a versatile element. Now, another use has been found: magnets. One would not expect pure...

  17. Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials and organisms

    SciTech Connect (OSTI)

    Goodson, Boyd M.

    1999-12-01T23:59:59.000Z

    Conventional nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) are fundamentally challenged by the insensitivity that stems from the ordinarily low spin polarization achievable in even the strongest NMR magnets. However, by transferring angular momentum from laser light to electronic and nuclear spins, optical pumping methods can increase the nuclear spin polarization of noble gases by several orders of magnitude, thereby greatly enhancing their NMR sensitivity. This dissertation is primarily concerned with the principles and practice of optically pumped nuclear magnetic resonance (OPNMR). The enormous sensitivity enhancement afforded by optical pumping noble gases can be exploited to permit a variety of novel NMR experiments across many disciplines. Many such experiments are reviewed, including the void-space imaging of organisms and materials, NMR and MRI of living tissues, probing structure and dynamics of molecules in solution and on surfaces, and zero-field NMR and MRI.

  18. Optically Enhanced Magnetic Resonance

    E-Print Network [OSTI]

    Suter, Dieter

    , like spatial structures or molecular dynamics. While the direct excitation of nuclear spin transitions.1 Motivation The physical mechanism of nuclear magnetic resonance spectroscopy, the excitation of transitions light for polarizing the spin system or for observing its dynamics. This possibility arises from

  19. Rotary magnetic heat pump

    DOE Patents [OSTI]

    Kirol, Lance D. (Shelly, ID)

    1988-01-01T23:59:59.000Z

    A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation.

  20. Rotary magnetic heat pump

    DOE Patents [OSTI]

    Kirol, L.D.

    1987-02-11T23:59:59.000Z

    A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.

  1. Magnetic resonance apparatus

    DOE Patents [OSTI]

    Jackson, Jasper A. (Los Alamos, NM); Cooper, Richard K. (Los Alamos, NM)

    1982-01-01T23:59:59.000Z

    Means for producing a region of homogeneous magnetic field remote from the source of the field, wherein two equal field sources are arranged axially so their fields oppose, producing a region near the plane perpendicular to the axis midway between the sources where the radial component of the field goes through a maximum. Near the maximum, the field is homogeneous over prescribed regions.

  2. Magnetic Monopole Searches

    E-Print Network [OSTI]

    G. Giacomelli; L. Patrizii

    2005-06-07T23:59:59.000Z

    In these lecture notes we discuss the status of the searches for classical Dirac Magnetic Monopoles (MMs) at accelerators, for GUT superheavy MMs in the penetrating cosmic radiation and for Intermediate Mass MMs. Also the searches for nuclearites and Q-balls are considered.

  3. Magnetic refrigeration for spacecraft systems

    SciTech Connect (OSTI)

    Barclay, J.A.

    1981-01-01T23:59:59.000Z

    Magnetic refrigerators, i.e., those that use the magnetocaloric effect of a magnetic working material in a thermodynamic cycle, offer potentially reliable, and efficient refrigeration over a variety of temperature ranges and cooling powers. A descriptive analysis of magnetic refrigeration systems is performed with particular emphasis on more efficient infrared detector cooling. Three types of magnetic refrigerator designs are introduced to illustrate some of the possibilities.

  4. Ames Lab 101: Magnetic Refrigeration

    ScienceCinema (OSTI)

    Pecharsky, Vitalij

    2013-03-01T23:59:59.000Z

    Vitalij Pecharsky, distinguished professor of materials science and engineering, discusses his research in magnetic refrigeration at Ames Lab.

  5. Ames Lab 101: Magnetic Refrigeration

    SciTech Connect (OSTI)

    Pecharsky, Vitalij

    2011-01-01T23:59:59.000Z

    Vitalij Pecharsky, distinguished professor of materials science and engineering, discusses his research in magnetic refrigeration at Ames Lab.

  6. Magnetic reconnection in nontoroidal plasmas

    SciTech Connect (OSTI)

    Boozer, Allen H. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)

    2005-07-15T23:59:59.000Z

    Magnetic reconnection is a major issue in solar and astrophysical plasmas. The mathematical result that the evolution of a magnetic field with only point nulls is always locally ideal limits the nature of reconnection in nontoroidal plasmas. Here it is shown that the exponentially increasing separation of neighboring magnetic field lines, which is generic, tends to produce rapid magnetic reconnection if the length of the field lines is greater than about 20 times the exponentiation, or Lyapunov, length.

  7. Dependence of Brownian and Néel relaxation times on magnetic field strength

    SciTech Connect (OSTI)

    Deissler, Robert J., E-mail: rjd42@case.edu; Wu, Yong; Martens, Michael A. [Department of Physics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States)] [Department of Physics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States)

    2014-01-15T23:59:59.000Z

    Purpose: In magnetic particle imaging (MPI) and magnetic particle spectroscopy (MPS) the relaxation time of the magnetization in response to externally applied magnetic fields is determined by the Brownian and Néel relaxation mechanisms. Here the authors investigate the dependence of the relaxation times on the magnetic field strength and the implications for MPI and MPS. Methods: The Fokker–Planck equation with Brownian relaxation and the Fokker–Planck equation with Néel relaxation are solved numerically for a time-varying externally applied magnetic field, including a step-function, a sinusoidally varying, and a linearly ramped magnetic field. For magnetic fields that are applied as a step function, an eigenvalue approach is used to directly calculate both the Brownian and Néel relaxation times for a range of magnetic field strengths. For Néel relaxation, the eigenvalue calculations are compared to Brown's high-barrier approximation formula. Results: The relaxation times due to the Brownian or Néel mechanisms depend on the magnitude of the applied magnetic field. In particular, the Néel relaxation time is sensitive to the magnetic field strength, and varies by many orders of magnitude for nanoparticle properties and magnetic field strengths relevant for MPI and MPS. Therefore, the well-known zero-field relaxation times underestimate the actual relaxation times and, in particular, can underestimate the Néel relaxation time by many orders of magnitude. When only Néel relaxation is present—if the particles are embedded in a solid for instance—the authors found that there can be a strong magnetization response to a sinusoidal driving field, even if the period is much less than the zero-field relaxation time. For a ferrofluid in which both Brownian and Néel relaxation are present, only one relaxation mechanism may dominate depending on the magnetic field strength, the driving frequency (or ramp time), and the phase of the magnetization relative to the applied magnetic field. Conclusions: A simple treatment of Néel relaxation using the common zero-field relaxation time overestimates the relaxation time of the magnetization in situations relevant for MPI and MPS. For sinusoidally driven (or ramped) systems, whether or not a particular relaxation mechanism dominates or is even relevant depends on the magnetic field strength, the frequency (or ramp time), and the phase of the magnetization relative to the applied magnetic field.

  8. Future Directions for Magnetic Sensors

    E-Print Network [OSTI]

    and Engineering Laboratory Magnetic tunnel junction (MTJ) sensors are rapidly becoming the technology of choiceFuture Directions for Magnetic Sensors: HYBRIDMATERIALS Our goal is to develop the scientific expertise needed to allow modeling and simulation to become the driving force in improving magnetic sensors

  9. Club! page 16 Using magnets

    E-Print Network [OSTI]

    Weston, Ken

    at the Magnet Lab like? Often, it's about solving problems. That's what engineers Scott Bole and Lee Marks didRobotics Club! page 16 Using magnets to analyze oil page 28 #12;editor's note What's a typical day recently. Their story began when Lee noticed something odd going on during a magnet-building project: When

  10. LABORATORY VI ELECTRICITY FROM MAGNETISM

    E-Print Network [OSTI]

    Minnesota, University of

    LABORATORY VI ELECTRICITY FROM MAGNETISM Lab VI - 1 In the previous problems you explored the magnetic field and its effect on moving charges. You also saw how electric currents could create magnetic can give rise to electric currents. This is the effect that allows the generation of electricity

  11. Low-temperature magnetic refrigerator

    DOE Patents [OSTI]

    Barclay, J.A.

    1983-05-26T23:59:59.000Z

    The invention relates to magnetic refrigeration and more particularly to low temperature refrigeration between about 4 and about 20 K, with an apparatus and method utilizing a belt of magnetic material passed in and out of a magnetic field with heat exchangers within and outside the field operably disposed to accomplish refrigeration.

  12. Low-temperature magnetic refrigerator

    DOE Patents [OSTI]

    Barclay, John A. (Los Alamos, NM)

    1985-01-01T23:59:59.000Z

    The disclosure is directed to a low temperature 4 to 20 K. refrigeration apparatus and method utilizing a ring of magnetic material moving through a magnetic field. Heat exchange is accomplished in and out of the magnetic field to appropriately utilize the device to execute Carnot and Stirling cycles.

  13. Optical imaging correlates with magnetic resonance imaging breast density and reveals composition changes during neoadjuvant chemotherapy

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    index that corresponds to increased vascu- lar density [32]. DOSI scanning is performed without compression

  14. Method of making permanent magnets

    DOE Patents [OSTI]

    McCallum, R.W.; Dennis, K.W.; Lograsso, B.K.; Anderson, I.E.

    1993-09-07T23:59:59.000Z

    A method for making an isotropic permanent magnet comprises atomizing a melt of a rare earth-transition metal alloy (e.g., an Nd--Fe--B alloy enriched in Nd and B) under conditions to produce protectively coated, rapidly solidified, generally spherical alloy particles. Wherein a majority of the particles are produced/size classified within a given size fraction (e.g., 5 to 40 microns diameter) exhibiting optimum as-atomized magnetic properties and subjecting the particles to concurrent elevated temperature and elevated isotropic pressure for a time effective to yield a densified, magnetically isotropic magnet compact having enhanced magnetic properties and mechanical properties. 13 figures.

  15. Magnetic Edge States in Graphene

    E-Print Network [OSTI]

    Gabriela Murguia

    2010-08-29T23:59:59.000Z

    Magnetic confinement in graphene has been of recent and growing interest because its potential applications in nanotechnology. In particular, the observation of the so called magnetic edge states in graphene has opened the possibility to deepen into the generation of spin currents and its applications in spintronics. We study the magnetic edge states of quasi-particles arising in graphene monolayers due to an inhomogeneous magnetic field of a magnetic barrier in the formalism of the two-dimensional massless Dirac equation. We also show how the solutions of such states in each of both triangular sublattices of the graphene are related through a supersymmetric transformation in the quantum mechanical sense.

  16. Fast superconducting magnetic field switch

    DOE Patents [OSTI]

    Goren, Yehuda (Mountain View, CA); Mahale, Narayan K. (The Woodlands, TX)

    1996-01-01T23:59:59.000Z

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.

  17. SU-E-J-233: A Facility for Radiobiological Experiments in a Large Magnetic Field

    SciTech Connect (OSTI)

    Carlone, M; Heaton, R; Keller, H [Princess Margaret Hospital, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada); Wouters, B [Ontario Cancer Institute, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada); Jaffray, D [Princess Margaret Hospital, Toronto, ON (Canada); Ontario Cancer Institute, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada)

    2014-06-01T23:59:59.000Z

    Purpose: There is considerable interest in developing medical linear accelerators with integrated image guidance by MRI. Less work has been done on the fundamental biology of cell survival in the presence of a strong magnetic field. The purpose of this work is to describe an experimental system capable of measuring cell survival response in the types of MRI-linac systems currently under development. Methods: We have integrated a cobalt irradiator with a solenoid magnet. The solenoid magnet has inner diameter of 10 cm. To enable measurement of the biological effects as a function of depth, we are utilizing the sliced gel technique, in which cells are embedded and fixed within a gelatin matrix. Irradiated cells at defined positions (sub mm resolution) can subsequently be recovered and assessed for cell survival or other biological effects. Results: The magnetic field profile in the solenoid has a peak magnetic field 36 cm below the top edge of the magnet bore and can be placed at and SAD of 100 cm. At a solenoid current of 35 A, the peak magnetic field is 0.25 T. The dose rate of the cobalt irradiator is 16 cGy/min at 100 cm SAD. EBT3 film was used to demonstrate the system functionality. It was irradiated at 1 cm depth at 100 cm SSD with a 4×4 field to 1.5 Gy in a 0.25 T magnetic field. The dose profile was similar between this film and the control exposure without magnetic field. Conclusion: Integrating a cobalt irradiator with a high field magnet is demonstrated. The magnetic field at the cobalt defining head was minimal and did not interfere with the functioning of this unit. Cell survival experiments can be reproduced exactly in the presence or absence of a magnetic field since a resistive magnet is used.

  18. Transient magnetic field and temperature modeling in large magnet applications

    SciTech Connect (OSTI)

    Gurol, H.; Hardy, G.E.; Peck, S.D.; Leung, E. (General Dynamics Corp., San Diego, CA (USA). Space Systems Div.)

    1989-07-01T23:59:59.000Z

    This paper discusses a coupled magnetic/thermal model developed to study heat and magnetic field diffusion in conducting materials subject to time-varying external fields. There are numerous applications, both military and commercial. These include: energy storage devices, pulsed power transformers, and electromagnetic launchers. The time scales of interest may range from a magnetic field pulse of a microsecond in an electromagnetic launcher, to hundreds of seconds in an energy storage magnet. The problem can be dominated by either the magnetic field or heat diffusion, depending on the temperature and the material properties of the conductor. In general, heat diffuses much more rapidly in high electrical conductivity materials of cryogenic temperatures. The magnetic field takes longer to diffuse, since screening currents can be rapidly set up which shield the interior of the material from further magnetic field penetration. Conversely, in high resistivity materials, the magnetic field diffuses much more rapidly. A coupled two-dimensional thermal/magnetic model has been developed. The results of this model, showing the time and spatial variation of the magnetic field and temperature, are discussed for the projectile of an electromagnetic launcher.

  19. Magnetic shielding design analysis

    SciTech Connect (OSTI)

    Kerns, J.A.; LaPaz, A.D.; Fabyan, J.

    1983-12-27T23:59:59.000Z

    Two passive magnetic-shielding-design approaches for static external fields are reviewed. The first approach uses the shielding solutions for spheres and cylinders while the second approach requires solving Maxwell's equations. Experimental data taken at LLNL are compared with the results from these shieldings-design methods, and improvements are recommended for the second method. Design considerations are discussed here along with the importance of material gaps in the shield.

  20. Advances in Lymphatic Imaging and Drug Delivery

    SciTech Connect (OSTI)

    Nune, Satish K.; Gunda, Padmaja; Majeti, Bharat K.; Thallapally, Praveen K.; Laird, Forrest M.

    2011-09-10T23:59:59.000Z

    Cancer remains the second leading cause of death after heart disease in the US. While metastasized cancers such as breast, prostate, and colon are incurable, before their distant spread, these diseases will have invaded the lymphatic system as a first step in their progression. Hence, proper evaluation of the disease state of the lymphatics which drain a tumor site is crucial to staging and the formation of a treatment plan. Current lymphatic imaging modalities with visible dyes and radionucleotide tracers offer limited sensitivity and poor resolution; however, newer tools using nanocarriers, quantum dots, and magnetic resonance imaging promise to vastly improve the staging of lymphatic spread without needless biopsies. Concurrent with the improvement of lymphatic imaging agents, has been the development of drug carriers that can localize chemotherapy to the lymphatic system, thus improving the treatment of localized disease while minimizing the exposure of healthy organs to cytotoxic drugs. This review will focus on polymeric systems that have been developed for imaging and drug delivery to the lymph system, how these new devices improve upon current technologies, and where further improvement is needed.

  1. Method for high resolution magnetic resonance analysis using magic angle technique

    DOE Patents [OSTI]

    Wind, Robert A.; Hu, Jian Zhi

    2003-12-30T23:59:59.000Z

    A method of performing a magnetic resonance analysis of a biological object that includes 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. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.

  2. Method for high resolution magnetic resonance analysis using magic angle technique

    DOE Patents [OSTI]

    Wind, Robert A.; Hu, Jian Zhi

    2004-12-28T23:59:59.000Z

    A method of performing a magnetic resonance analysis of a biological object that includes 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. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.

  3. Quantitative luminescence imaging system

    DOE Patents [OSTI]

    Erwin, D.N.; Kiel, J.L.; Batishko, C.R.; Stahl, K.A.

    1990-08-14T23:59:59.000Z

    The QLIS images and quantifies low-level chemiluminescent reactions in an electromagnetic field. It is capable of real time nonperturbing measurement and simultaneous recording of many biochemical and chemical reactions such as luminescent immunoassays or enzyme assays. The system comprises image transfer optics, a low-light level digitizing camera with image intensifying microchannel plates, an image process or, and a control computer. The image transfer optics may be a fiber image guide with a bend, or a microscope, to take the light outside of the RF field. Output of the camera is transformed into a localized rate of cumulative digitalized data or enhanced video display or hard-copy images. The system may be used as a luminescent microdosimetry device for radiofrequency or microwave radiation, as a thermal dosimeter, or in the dosimetry of ultra-sound (sonoluminescence) or ionizing radiation. It provides a near-real-time system capable of measuring the extremely low light levels from luminescent reactions in electromagnetic fields in the areas of chemiluminescence assays and thermal microdosimetry, and is capable of near-real-time imaging of the sample to allow spatial distribution analysis of the reaction. It can be used to instrument three distinctly different irradiation configurations, comprising (1) RF waveguide irradiation of a small Petri-dish-shaped sample cell, (2) RF irradiation of samples in a microscope for the microscopic imaging and measurement, and (3) RF irradiation of small to human body-sized samples in an anechoic chamber. 22 figs.

  4. Quantitative luminescence imaging system

    DOE Patents [OSTI]

    Erwin, David N. (San Antonio, TX); Kiel, Johnathan L. (San Antonio, TX); Batishko, Charles R. (West Richland, WA); Stahl, Kurt A. (Richland, WA)

    1990-01-01T23:59:59.000Z

    The QLIS images and quantifies low-level chemiluminescent reactions in an electromagnetic field. It is capable of real time nonperturbing measurement and simultaneous recording of many biochemical and chemical reactions such as luminescent immunoassays or enzyme assays. The system comprises image transfer optics, a low-light level digitizing camera with image intensifying microchannel plates, an image process or, and a control computer. The image transfer optics may be a fiber image guide with a bend, or a microscope, to take the light outside of the RF field. Output of the camera is transformed into a localized rate of cumulative digitalized data or enhanced video display or hard-copy images. The system may be used as a luminescent microdosimetry device for radiofrequency or microwave radiation, as a thermal dosimeter, or in the dosimetry of ultra-sound (sonoluminescence) or ionizing radiation. It provides a near-real-time system capable of measuring the extremely low light levels from luminescent reactions in electromagnetic fields in the areas of chemiluminescence assays and thermal microdosimetry, and is capable of near-real-time imaging of the sample to allow spatial distribution analysis of the reaction. It can be used to instrument three distinctly different irradiation configurations, comprising (1) RF waveguide irradiation of a small Petri-dish-shaped sample cell, (2) RF irradiation of samples in a microscope for the microscopie imaging and measurement, and (3) RF irradiation of small to human body-sized samples in an anechoic chamber.

  5. BNL | ICS Imaging

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    due to the phase-contrast effect. This method will be useful for quantitative computed tomography applications of Thomson sources. High-resolution radiographic image of a wasp...

  6. Ferroelectric optical image comparator

    DOE Patents [OSTI]

    Butler, M.A.; Land, C.E.; Martin, S.J.; Pfeifer, K.B.

    1993-11-30T23:59:59.000Z

    A ferroelectric optical image comparator has a lead lanthanum zirconate titanate thin-film device which is constructed with a semi-transparent or transparent conductive first electrode on one side of the thin film, a conductive metal second electrode on the other side of the thin film, and the second electrode is in contact with a nonconducting substrate. A photoinduced current in the device represents the dot product between a stored image and an image projected onto the first electrode. One-dimensional autocorrelations are performed by measuring this current while displacing the projected image. 7 figures.

  7. High Magnetic Field Multipoles Generated by Superconductor Magnetization within a Set of Nested Superconducting Correction Coils

    E-Print Network [OSTI]

    Green, M.A.

    2011-01-01T23:59:59.000Z

    magnetization of the superconductor in the long correctorsMultipoles Generated by Superconductor Magnetization WithinMULTIPOLES GENERATED BY SUPERCONDUCTOR MAGNETIZATION WITHIN

  8. Restoring functional PET Images using Anatomical MR Images

    E-Print Network [OSTI]

    Mosegaard, Klaus

    Restoring functional PET Images using Anatomical MR Images Peter Philipsen, Ulrik Kjems, Peter Toft signal to noise ratio and the low spa­ tial resolution in Positron Emission Tomography (PET) images ? And Positron Emission Tomography (PET) Images? ffl Segmentation of MR Images ­ Extraction of important edges

  9. Compression of Computer Graphics Images with Image-Based Rendering

    E-Print Network [OSTI]

    Shahabi, Cyrus

    Compression of Computer Graphics Images with Image-Based Rendering Ilmi Yoon and Ulrich Neumann information from previously rendered images. Images predicted from prior images are combined with a residual-based rendering tech- nique provides accurate motion prediction and accelerates rendering at the same time

  10. Chaotic Dynamics of Spin-Valve Oscillators Z. Yang and S. Zhang

    E-Print Network [OSTI]

    Li, Charles

    Chaotic Dynamics of Spin-Valve Oscillators Z. Yang and S. Zhang Department of Physics and Astronomy oscillators with tunable mi- crowave frequencies in spin valves are very desirable for magnetic storage it is not an intrinsic property of the current-driven oscillator. Here we consider a single-domain current-driven spin-valve

  11. Use of diffusion tensor imaging to assess the impact of normobaric hyperoxia within at-risk pericontusional tissue after traumatic brain injury

    E-Print Network [OSTI]

    Veenith, Tonny V.; Carter, Eleanor L.; Grossac, Julia; Newcombe, Virginia F.; Outtrim, Joanne G.; Nallapareddy, Sridhar; Lupson, Victoria; Correia, Marta M.; Mada, Marius M.; Williams, Guy B.; Menon, David K.; Coles, Jonathan P.

    2014-07-09T23:59:59.000Z

    Glamorgan, Wales, UK). Diffusion tensor imaging was obtained at each level after an equilibration period of 15min to assess the impact of oxygen therapy on normal brain. Imaging All subjects were scanned using a 3T Siemens Verio magnetic resonance imaging... scanner (Siemens AG, Erlangen, Germany) within the Wolfson Brain Imaging Centre (WBIC), University of Cambridge. During the study period there were no major changes or upgrades to the scanner or software. The sequences obtained were structural sequences...

  12. Use of diffusion tensor imaging to assess the impact of normobaric hyperoxia within at-risk pericontusional tissue following traumatic brain injury

    E-Print Network [OSTI]

    Veenith, T.V.; Carter, E.L.; Grossac, J.; Newcombe, V.F.; Outtrim, J.G.; Nallapareddy, Sridhar; Lupson, Victoria; Correia, M.M.; Mada, Marius M.; Williams, Guy B.; Menon, David K.; Coles, J.P.

    2014-07-08T23:59:59.000Z

    Glamorgan, Wales, UK). Diffusion tensor imaging was obtained at each level after an equilibration period of 15min to assess the impact of oxygen therapy on normal brain. Imaging All subjects were scanned using a 3T Siemens Verio magnetic resonance imaging... scanner (Siemens AG, Erlangen, Germany) within the Wolfson Brain Imaging Centre (WBIC), University of Cambridge. During the study period there were no major changes or upgrades to the scanner or software. The sequences obtained were structural sequences...

  13. Fast imaging of intact and shattered cryogenic neon pellets

    SciTech Connect (OSTI)

    Wang, Zhehui, E-mail: zwang@lanl.gov [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Combs, S. K.; Baylor, L. R.; Foust, C. R.; Lyttle, M. S.; Meitner, S. J.; Rasmussen, D. A. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-11-15T23:59:59.000Z

    Compact condensed-matter injection technologies are increasingly used in magnetic fusion. One recent application is in disruption mitigation. An imaging system with less-than-100-µm- and sub-µs-resolution is described and used to characterize intact and shattered cryogenic neon pellets. Shattered pellets contain fine particles ranging from tens of µm to about 7 mm. Time-of-flight analyses indicate that pellets could slow down if hitting the wall of the guide tube. Fast high-resolution imaging systems are thus useful to neon and other condensed-matter injector development.

  14. Continuous magnetic separator and process

    DOE Patents [OSTI]

    Oder, Robin R. (Export, PA); Jamison, Russell E. (Lower Burrell, PA)

    2008-04-22T23:59:59.000Z

    A continuous magnetic separator and process for separating a slurry comprising magnetic particles into a clarified stream and a thickened stream. The separator has a container with a slurry inlet, an overflow outlet for the discharge of the clarified slurry stream, and an underflow outlet for the discharge of a thickened slurry stream. Magnetic particles in the slurry are attracted to, and slide down, magnetic rods within the container. The slurry is thus separated into magnetic concentrate and clarified slurry. Flow control means can be used to control the ratio of the rate of magnetic concentrate to the rate of clarified slurry. Feed control means can be used to control the rate of slurry feed to the slurry inlet.

  15. Thin film superconductor magnetic bearings

    DOE Patents [OSTI]

    Weinberger, Bernard R. (Avon, CT)

    1995-12-26T23:59:59.000Z

    A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

  16. Magnetic cooling at Risoe DTU

    E-Print Network [OSTI]

    Nielsen, K K; Jensen, J B; Bahl, C R H; Pryds, N; Smith, A; Nordentoft, A; Hattel, J

    2009-01-01T23:59:59.000Z

    Magnetic refrigeration at room temperature is of great interest due to a long-term goal of making refrigeration more energy-efficient, less noisy and free of any environmentally hostile materials. A refrigerator utilizing an active magnetic regenerator (AMR) is based on the magnetocaloric effect, which manifests itself as a temperature change in magnetic materials when subjected to a varying magnetic field. In this work we present the current state of magnetic refrigeration research at Risoe DTU with emphasis on the numerical modeling of an existing AMR test machine. A 2D numerical heat-transfer and fluid-flow model that represents the experimental setup is presented. Experimental data of both no-heat load and heat load situations are compared to the model. Moreover, results from the numerical modeling of the permanent magnet design used in the system are presented.

  17. Journal of Magnetism and Magnetic Materials 281 (2004) 272275 Effects of high magnetic field annealing on texture and

    E-Print Network [OSTI]

    Garmestani, Hamid

    Journal of Magnetism and Magnetic Materials 281 (2004) 272­275 Effects of high magnetic field annealing on texture and magnetic properties of FePd D.S. Lia, *, H. Garmestania , Shi-shen Yanb , M China c National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive

  18. The MagLab's ultra-wide-bore (105mm) 21.1T NMR/MRI magnet provides an opportunity to use low gamma, low

    E-Print Network [OSTI]

    McQuade, D. Tyler

    The MagLab's ultra-wide-bore (105mm) 21.1T NMR/MRI magnet provides an opportunity to use low gamma, low sensitive nuclei for MR imaging. The potential of nuclei such as chlorine remains largely and the capability of MRI at ultra high magnetic fields to observe glioma. The finding of an increased concentration

  19. Adaptive wiener image restoration kernel

    DOE Patents [OSTI]

    Yuan, Ding (Henderson, NV)

    2007-06-05T23:59:59.000Z

    A method and device for restoration of electro-optical image data using an adaptive Wiener filter begins with constructing imaging system Optical Transfer Function, and the Fourier Transformations of the noise and the image. A spatial representation of the imaged object is restored by spatial convolution of the image using a Wiener restoration kernel.

  20. Scandinavian Workshop on Imaging

    E-Print Network [OSTI]

    Mosegaard, Klaus

    Barcode Imaging of Chocolate Milk Quan.fica.on of Microstructures in Freeze.on of Fat Content in Raw Beef Cut Meat Evalua.on by RGB-to-spectrum Imaging.on to Visualizing Meat Products Characteriza.on of Commercial Danish Apple Cul.var Using Novel

  1. Heart imaging method

    DOE Patents [OSTI]

    Collins, H. Dale (Richland, WA); Gribble, R. Parks (Richland, WA); Busse, Lawrence J. (Littleton, CO)

    1991-01-01T23:59:59.000Z

    A method for providing an image of the human heart's electrical system derives time-of-flight data from an array of EKG electrodes and this data is transformed into phase information. The phase information, treated as a hologram, is reconstructed to provide an image in one or two dimensions of the electrical system of the functioning heart.

  2. DOUBLE MAJORS Imaging Science + ...

    E-Print Network [OSTI]

    Zanibbi, Richard

    DOUBLE MAJORS Imaging Science + ... Applied Mathematics Biomedical Sciences Computer Science Undergraduate Research Internships and Cooperative Education (Co-op) (optional) Study Abroad WHY IMAGING SCIENCE Science: BS, MS, PhD Color Science: MS, PhD BS + MS/PhD Combos HUMAN VISION BIO- MEDICAL ASTRO- PHYSICS

  3. Fluorescent image tracking velocimeter

    DOE Patents [OSTI]

    Shaffer, Franklin D. (Library, PA)

    1994-01-01T23:59:59.000Z

    A multiple-exposure fluorescent image tracking velocimeter (FITV) detects and measures the motion (trajectory, direction and velocity) of small particles close to light scattering surfaces. The small particles may follow the motion of a carrier medium such as a liquid, gas or multi-phase mixture, allowing the motion of the carrier medium to be observed, measured and recorded. The main components of the FITV include: (1) fluorescent particles; (2) a pulsed fluorescent excitation laser source; (3) an imaging camera; and (4) an image analyzer. FITV uses fluorescing particles excited by visible laser light to enhance particle image detectability near light scattering surfaces. The excitation laser light is filtered out before reaching the imaging camera allowing the fluoresced wavelengths emitted by the particles to be detected and recorded by the camera. FITV employs multiple exposures of a single camera image by pulsing the excitation laser light for producing a series of images of each particle along its trajectory. The time-lapsed image may be used to determine trajectory and velocity and the exposures may be coded to derive directional information.

  4. Medical imaging systems

    DOE Patents [OSTI]

    Frangioni, John V. (Wayland, MA)

    2012-07-24T23:59:59.000Z

    A medical imaging system provides simultaneous rendering of visible light and fluorescent images. The system may employ dyes in a small-molecule form that remains in a subject's blood stream for several minutes, allowing real-time imaging of the subject's circulatory system superimposed upon a conventional, visible light image of the subject. The system may also employ dyes or other fluorescent substances associated with antibodies, antibody fragments, or ligands that accumulate within a region of diagnostic significance. In one embodiment, the system provides an excitation light source to excite the fluorescent substance and a visible light source for general illumination within the same optical guide that is used to capture images. In another embodiment, the system is configured for use in open surgical procedures by providing an operating area that is closed to ambient light. More broadly, the systems described herein may be used in imaging applications where a visible light image may be usefully supplemented by an image formed from fluorescent emissions from a fluorescent substance that marks areas of functional interest.

  5. Tests of prototype SSC magnets

    SciTech Connect (OSTI)

    Strait, J.

    1987-04-24T23:59:59.000Z

    Results are presented from tests of the first two full length prototype SSC dipole magnets. Magnetic field measurements have been made at currents up to 2000 A. The two magnets achieved peak currents at 4.5K of 5790 A and 6450 A, respectively, substantially below the short sample limit of 6700 A. These peak values, however, could not be achieved reproducibly. Data are presented from studies performed to try to understand the poor quench performance.

  6. Time encoded radiation imaging

    DOE Patents [OSTI]

    Marleau, Peter; Brubaker, Erik; Kiff, Scott

    2014-10-21T23:59:59.000Z

    The various technologies presented herein relate to detecting nuclear material at a large stand-off distance. An imaging system is presented which can detect nuclear material by utilizing time encoded imaging relating to maximum and minimum radiation particle counts rates. The imaging system is integrated with a data acquisition system that can utilize variations in photon pulse shape to discriminate between neutron and gamma-ray interactions. Modulation in the detected neutron count rates as a function of the angular orientation of the detector due to attenuation of neighboring detectors is utilized to reconstruct the neutron source distribution over 360 degrees around the imaging system. Neutrons (e.g., fast neutrons) and/or gamma-rays are incident upon scintillation material in the imager, the photons generated by the scintillation material are converted to electrical energy from which the respective neutrons/gamma rays can be determined and, accordingly, a direction to, and the location of, a radiation source identified.

  7. Confocal coded aperture imaging

    DOE Patents [OSTI]

    Tobin, Jr., Kenneth William (Harriman, TN); Thomas, Jr., Clarence E. (Knoxville, TN)

    2001-01-01T23:59:59.000Z

    A method for imaging a target volume comprises the steps of: radiating a small bandwidth of energy toward the target volume; focusing the small bandwidth of energy into a beam; moving the target volume through a plurality of positions within the focused beam; collecting a beam of energy scattered from the target volume with a non-diffractive confocal coded aperture; generating a shadow image of said aperture from every point source of radiation in the target volume; and, reconstructing the shadow image into a 3-dimensional image of the every point source by mathematically correlating the shadow image with a digital or analog version of the coded aperture. The method can comprise the step of collecting the beam of energy scattered from the target volume with a Fresnel zone plate.

  8. Metallic Magnetic Hetrostructures

    E-Print Network [OSTI]

    Leung, Chi Wah

    cross-over and exchange bias in Co/FeMn/CuNi trilayers’, M.G. Blamire, M. Ali, C.W. Leung, C.H. Marrows and B.J. Hickey, Phys. Rev. Lett., (submitted). iii Presentations - Joint Magnetics Workshop 01 (University of Cardiff, Cardiff, 2001) ‘Study... , in no particular order: Zoe Barber, Ashish Grag, Karen Yates, Neil Mathur, Bas van Aken, Brian Pang, Moon-Ho Jo, James Chapman, Mary Vickers, Neil Todd, Jerome Wolfman, Pak Kin Wong and Robert Hadfield. During the course of the project I have spent two weeks...

  9. Try This: Household Magnets

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening a solidSynthesisAppliancesTrending:Schedule FYHousehold Magnets

  10. Recycling Magnets | Jefferson Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection RadiationRecord-Setting MicroscopyJuneRecycling Magnets July 15, 2013

  11. Measurements of magnetic field alignment

    SciTech Connect (OSTI)

    Kuchnir, M.; Schmidt, E.E.

    1987-11-06T23:59:59.000Z

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

  12. BNL Direct Wind Superconducting Magnets

    SciTech Connect (OSTI)

    Parker, B.; Anerella, M.; Escallier, J.; Ghosh, A.; Jain, A.; Marone, A.; Muratore, A.; Wanderer, P.

    2011-09-12T23:59:59.000Z

    BNL developed Direct Wind magnet technology is used to create a variety of complex multi-functional multi-layer superconducting coil structures without the need for creating custom production tooling and fixturing for each new project. Our Direct Wind process naturally integrates prestress into the coil structure so external coil collars and yokes are not needed; the final coil package transverse size can then be very compact. Direct Wind magnets are produced with very good field quality via corrections applied during the course of coil winding. The HERA-II and BEPC-II Interaction Region (IR) magnet, J-PARC corrector and Alpha antihydrogen magnetic trap magnets and our BTeV corrector magnet design are discussed here along with a full length ILC IR prototype magnet presently in production and the coils that were wound for an ATF2 upgrade at KEK. A new IR septum magnet design concept for a 6.2 T combined-function IR magnet for eRHIC, a future RHIC upgrade, is introduced here.

  13. $?^{-}$, $?^{* -}$, $?^{* -}$ and $?^{-}$ decuplet baryon magnetic moments

    E-Print Network [OSTI]

    Milton Dean Slaughter

    2011-04-04T23:59:59.000Z

    The properties of the ground state $U$-Spin $={3/2}$ baryon decuplet magnetic moments $\\Delta^{-}$, $\\Xi^{* -}$, $\\Sigma^{* -}$ and $\\Omega^{-}$ and their ground state spin 1/2 cousins $p$, $n$, $\\Lambda$, $\\Sigma^{+}$, $\\Sigma^{0}$, $\\Sigma^{-}$, $\\Xi^{+}$, and $\\Xi^{-}$ have been studied for many years with a modicum of success. The magnetic moments of many are yet to be determined. Of the decuplet baryons, only the magnetic moment of the $\\Omega^{-}$ has been accurately determined. We calculate the magnetic moments of the \\emph{physical} decuplet $U$-Spin $={3/2}$ quartet members without ascribing any specific form to their quark structure or intra-quark interactions.

  14. Magnetic Refrigeration | GE Global Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    temperature," said Frank Johnson, a materials scientist and project leader on GE's magnetic refrigeration project. Developed over the past decade, these new magnetocaloric...

  15. Tunable exchange bias-like effect in patterned hard-soft two-dimensional lateral composites with perpendicular magnetic anisotropy

    SciTech Connect (OSTI)

    Hierro-Rodriguez, A., E-mail: ahierro@fc.up.pt; Alvarez-Prado, L. M.; Martín, J. I.; Alameda, J. M. [Departamento de Física, Universidad de Oviedo, C/Calvo Sotelo S/N, 33007 Oviedo (Spain); Centro de Investigación en Nanomateriales y Nanotecnología—CINN (CSIC—Universidad de Oviedo—Principado de Asturias), Parque Tecnológico de Asturias, 33428 Llanera (Spain); Teixeira, J. M. [IN-IFIMUP, Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua Campo Alegre 687, 4169-007 Porto (Portugal); Vélez, M. [Departamento de Física, Universidad de Oviedo, C/Calvo Sotelo S/N, 33007 Oviedo (Spain)

    2014-09-08T23:59:59.000Z

    Patterned hard-soft 2D magnetic lateral composites have been fabricated by e-beam lithography plus dry etching techniques on sputter-deposited NdCo{sub 5} thin films with perpendicular magnetic anisotropy. Their magnetic behavior is strongly thickness dependent due to the interplay between out-of-plane anisotropy and magnetostatic energy. Thus, the spatial modulation of thicknesses leads to an exchange coupled system with hard/soft magnetic regions in which rotatable anisotropy of the thicker elements provides an extra tool to design the global magnetic behavior of the patterned lateral composite. Kerr microscopy studies (domain imaging and magneto-optical Kerr effect magnetometry) reveal that the resulting hysteresis loops exhibit a tunable exchange bias-like shift that can be switched on/off by the applied magnetic field.

  16. Size and polydispersity effect on the magnetization of densely packed magnetic nanoparticles.

    E-Print Network [OSTI]

    Boyer, Edmond

    Size and polydispersity effect on the magnetization of densely packed magnetic nanoparticles Paris 13, 93017 Bobigny, France. The magnetic properties of densely packed magnetic nanoparticles (MNP) assemblies are investi- gated from Monte Carlo simulations. The case of iron oxide nanoparticles

  17. Electric-Field Control of Magnetism Intrinsic magnetoelectric coupling describes the microscopic interaction between magnetic and

    E-Print Network [OSTI]

    Maroncelli, Mark

    Electric-Field Control of Magnetism Intrinsic magnetoelectric coupling describes the microscopic interaction between magnetic and electric polarization in a single-phase material. The control of the magnetic of the two interactions. Moderate biaxial compression precipitates local magnetic competition

  18. Global Electrical Conductivity Magnetic Satellite Induction Studies

    E-Print Network [OSTI]

    Constable, Steve

    · Geomagnetic depth sounding (GDS) method Measure horizontal and vertical magnetic fields 2nd-varying magnetic field induces electric currents in conductors. × E = - B t Secondary magnetic fields created by these currents appose the primary magnetic field. So, conductors attenuate magnetic fields. 2nd

  19. Background Material Important Questions about Magnetism

    E-Print Network [OSTI]

    Mojzsis, Stephen J.

    Background Material Important Questions about Magnetism: 1) What is Magnetism?Magnetism is a force or repulsion due to charge is called the electric force. But what about magnetism, is there a fundamental property of some matter that makes things magnetic? The answer is: "sort of." Electric current

  20. Sandia National Laboratories: CSP Images & Videos

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Images & Videos CSP Images & Videos Image Gallery Videos Concentrating Solar Power Image Gallery A picture says a thousand words, especially on the World Wide Web. Both Sandia...

  1. Nanolithographically defined magnetic structures and quantum magnetic disk (invited)

    E-Print Network [OSTI]

    - creasing demands for magnetic storage devices with higher density, faster speed, lower power consumption, smaller size, and lower weight than the current state-of-the-art devices. Presently, most magnetic storage. Chou, Peter R. Krauss, and Linshu Kong NanoStructure Laboratory, Department of Electrical Engineering

  2. Performance Analysis between Two Sparsity Constrained MRI Methods: Highly Constrained Backprojection(HYPR) and Compressed Sensing(CS) for Dynamic Imaging 

    E-Print Network [OSTI]

    Arzouni, Nibal

    2012-10-19T23:59:59.000Z

    One of the most important challenges in dynamic magnetic resonance imaging (MRI) is to achieve high spatial and temporal resolution when it is limited by system performance. It is desirable to acquire data fast enough to capture the dynamics...

  3. NONTHERMAL HARD X-RAY EMISSIONS FROM MAGNETIC RECONNECTION IN THE SUN'S LOWER

    E-Print Network [OSTI]

    . R. China, jihs@bbso.njit.edu 2. Big Bear Solar Observatory, New Jersey Institute of Technology from magnetic reconnection in the solar lower atmosphere by analyzing an M1.0 class solar flare, as observed by full disk H images of Big Bear Solar Observatory (BBSO). HXR maps constructed from the Reuven

  4. Ventilation-Synchronous Magnetic Resonance Microscopy of Pulmonary Structure and Ventilation in

    E-Print Network [OSTI]

    Ventilation-Synchronous Magnetic Resonance Microscopy of Pulmonary Structure and Ventilation helium (3 He) gas to acquire images that dem- onstrate pulmonary vasculature and ventilated airways of these structures relative to the less vascular surrounding tissues. A constant- flow ventilator was developed

  5. Ghost Imaging with Blackbody Radiation

    E-Print Network [OSTI]

    Yangjian Cai; Shiyao Zhu

    2004-07-29T23:59:59.000Z

    We present a theoretical study of ghost imaging by using blackbody radiation source. A Gaussian thin lens equation for the ghost imaging, which depends on both paths, is derived. The dependences of the visibility and quality of the image on the transverse size and temperature of the blackbody are studied. The main differences between the ghost imaging by using the blackbody radiation and by using the entangled photon pairs are image-forming equation, and the visibility and quality of the image

  6. Magnetic Patterning of Permanent-Magnet Rotors for Microscale Motor/Generators

    E-Print Network [OSTI]

    Magnetic Patterning of Permanent-Magnet Rotors for Microscale Motor/Generators I. Zana* , F, USA Abstract We present and characterize a process to pattern magnetic poles on small permanent-magnet, this approach uses a ferromagnetic magnetizing head (MH) and an externally applied magnetic field, and it offers

  7. Direct torsional actuation of microcantilevers using magnetic excitation

    SciTech Connect (OSTI)

    Gosvami, Nitya Nand; Nalam, Prathima C.; Tam, Qizhan; Carpick, Robert W., E-mail: carpick@seas.upenn.edu [Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Exarhos, Annemarie L.; Kikkawa, James M. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2014-09-01T23:59:59.000Z

    Torsional mode dynamic force microscopy can be used for a wide range of studies including mapping lateral contact stiffness, torsional frequency or amplitude modulation imaging, and dynamic friction measurements of various materials. Piezo-actuation of the cantilever is commonly used, but it introduces spurious resonances, limiting the frequency range that can be sampled, and rendering the technique particularly difficult to apply in liquid medium where the cantilever oscillations are significantly damped. Here, we demonstrate a method that enables direct torsional actuation of cantilevers with high uniformity over wide frequency ranges by attaching a micrometer-scale magnetic bead on the back side of the cantilever. We show that when beads are magnetized along the width of the cantilever, efficient torsional actuation of the cantilevers can be achieved using a magnetic field produced from a solenoid placed underneath the sample. We demonstrate the capability of this technique by imaging atomic steps on graphite surfaces in tapping mode near the first torsional resonance of the cantilever in dodecane. The technique is also applied to map the variations in the lateral contact stiffness on the surface of graphite and polydiacetylene monolayers.

  8. SOLAR MAGNETIC TRACKING. IV. THE DEATH OF MAGNETIC FEATURES

    SciTech Connect (OSTI)

    Lamb, D. A.; Howard, T. A.; DeForest, C. E. [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Parnell, C. E. [School of Mathematics and Statistics, University of St. Andrews, St. Andrews, KY16 9SS (United Kingdom); Welsch, B. T., E-mail: derek@boulder.swri.edu [Space Sciences Laboratory, University of California-Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States)

    2013-09-10T23:59:59.000Z

    The removal of magnetic flux from the quiet-Sun photosphere is important for maintaining the statistical steady state of the magnetic field there, for determining the magnetic flux budget of the Sun, and for estimating the rate of energy injected into the upper solar atmosphere. Magnetic feature death is a measurable proxy for the removal of detectable flux, either by cancellation (submerging or rising loops, or reconnection in the photosphere) or by dispersal of flux. We used the SWAMIS feature tracking code to understand how nearly 2 Multiplication-Sign 10{sup 4} magnetic features die in an hour-long sequence of Hinode/SOT/NFI magnetograms of a region of the quiet Sun. Of the feature deaths that remove visible magnetic flux from the photosphere, the vast majority do so by a process that merely disperses the previously detected flux so that it is too small and too weak to be detected, rather than completely eliminating it. The behavior of the ensemble average of these dispersals is not consistent with a model of simple planar diffusion, suggesting that the dispersal is constrained by the evolving photospheric velocity field. We introduce the concept of the partial lifetime of magnetic features, and show that the partial lifetime due to Cancellation of magnetic flux, 22 hr, is three times slower than previous measurements of the flux turnover time. This indicates that prior feature-based estimates of the flux replacement time may be too short, in contrast with the tendency for this quantity to decrease as resolution and instrumentation have improved. This suggests that dispersal of flux to smaller scales is more important for the replacement of magnetic fields in the quiet Sun than observed bipolar cancellation. We conclude that processes on spatial scales smaller than those visible to Hinode dominate the processes of flux emergence and cancellation, and therefore also the quantity of magnetic flux that threads the photosphere.

  9. 2D electron temperature diagnostic using soft x-ray imaging technique

    SciTech Connect (OSTI)

    Nishimura, K., E-mail: nishim11@nuclear.es.kit.ac.jp; Sanpei, A., E-mail: sanpei@kit.ac.jp; Tanaka, H.; Ishii, G.; Kodera, R.; Ueba, R.; Himura, H.; Masamune, S. [Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585 (Japan)] [Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585 (Japan); Ohdachi, S.; Mizuguchi, N. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)] [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

    2014-03-15T23:59:59.000Z

    We have developed a two-dimensional (2D) electron temperature (T{sub e}) diagnostic system for thermal structure studies in a low-aspect-ratio reversed field pinch (RFP). The system consists of a soft x-ray (SXR) camera with two pin holes for two-kinds of absorber foils, combined with a high-speed camera. Two SXR images with almost the same viewing area are formed through different absorber foils on a single micro-channel plate (MCP). A 2D T{sub e} image can then be obtained by calculating the intensity ratio for each element of the images. We have succeeded in distinguishing T{sub e} image in quasi-single helicity (QSH) from that in multi-helicity (MH) RFP states, where the former is characterized by concentrated magnetic fluctuation spectrum and the latter, by broad spectrum of edge magnetic fluctuations.

  10. Scanning computed confocal imager

    DOE Patents [OSTI]

    George, John S. (Los Alamos, NM)

    2000-03-14T23:59:59.000Z

    There is provided a confocal imager comprising a light source emitting a light, with a light modulator in optical communication with the light source for varying the spatial and temporal pattern of the light. A beam splitter receives the scanned light and direct the scanned light onto a target and pass light reflected from the target to a video capturing device for receiving the reflected light and transferring a digital image of the reflected light to a computer for creating a virtual aperture and outputting the digital image. In a transmissive mode of operation the invention omits the beam splitter means and captures light passed through the target.

  11. Nuclear medicine imaging system

    DOE Patents [OSTI]

    Bennett, G.W.; Brill, A.B.; Bizais, Y.J.C.; Rowe, R.W.; Zubal, I.G.

    1983-03-11T23:59:59.000Z

    It is an object of this invention to provide a nuclear imaging system having the versatility to do positron annihilation studies, rotating single or opposed camera gamma emission studies, and orthogonal gamma emission studies. It is a further object of this invention to provide an imaging system having the capability for orthogonal dual multipinhole tomography. It is another object of this invention to provide a nuclear imaging system in which all available energy data, as well as patient physiological data, are acquired simultaneously in list mode.

  12. LABORATORY VI ELECTRICITY FROM MAGNETISM

    E-Print Network [OSTI]

    Minnesota, University of

    LABORATORY VI ELECTRICITY FROM MAGNETISM Lab VI - 1 In the previous problems you explored by electric currents. This lab will carry that investigation one step further, determining how changing magnetic fields can give rise to electric currents. This is the effect that allows the generation

  13. Magnetic bags in hyperbolic space

    E-Print Network [OSTI]

    Stefano Bolognesi; Derek Harland; Paul Sutcliffe

    2015-04-07T23:59:59.000Z

    A magnetic bag is an abelian approximation to a large number of coincident SU(2) BPS monopoles. In this paper we consider magnetic bags in hyperbolic space and derive their Nahm transform from the large charge limit of the discrete Nahm equation for hyperbolic monopoles. An advantage of studying magnetic bags in hyperbolic space, rather than Euclidean space, is that a range of exact charge N hyperbolic monopoles can be constructed, for arbitrarily large values of N, and compared with the magnetic bag approximation. We show that a particular magnetic bag (the magnetic disc) provides a good description of the axially symmetric N-monopole. However, an abelian magnetic bag is not a good approximation to a roughly spherical N-monopole that has more than N zeros of the Higgs field. We introduce an extension of the magnetic bag that does provide a good approximation to such monopoles and involves a spherical non-abelian interior for the bag, in addition to the conventional abelian exterior.

  14. Magnetic-field-dosimetry system

    DOE Patents [OSTI]

    Lemon, D.K.; Skorpik, J.R.; Eick, J.L.

    1981-01-21T23:59:59.000Z

    A device is provided for measuring the magnetic field dose and peak field exposure. The device includes three Hall-effect sensors all perpendicular to each other, sensing the three dimensional magnetic field and associated electronics for data storage, calculating, retrieving and display.

  15. Exergy analysis of magnetic refrigeration

    E-Print Network [OSTI]

    Lucia, Umberto

    2010-01-01T23:59:59.000Z

    One of the main challenges of the industry today is to face its impact on global warming considering that the greenhouse effect problem is not be solved completely yet. Magnetic refrigeration represents an environment-safe refrigeration technology. The magnetic refrigeration is analysed using the second law analysis and introducing exergy in order to obtain a model for engineering application.

  16. Magnetic bags in hyperbolic space

    E-Print Network [OSTI]

    Bolognesi, Stefano; Sutcliffe, Paul

    2015-01-01T23:59:59.000Z

    A magnetic bag is an abelian approximation to a large number of coincident SU(2) BPS monopoles. In this paper we consider magnetic bags in hyperbolic space and derive their Nahm transform from the large charge limit of the discrete Nahm equation for hyperbolic monopoles. An advantage of studying magnetic bags in hyperbolic space, rather than Euclidean space, is that a range of exact charge N hyperbolic monopoles can be constructed, for arbitrarily large values of N, and compared with the magnetic bag approximation. We show that a particular magnetic bag (the magnetic disc) provides a good description of the axially symmetric N-monopole. However, an abelian magnetic bag is not a good approximation to a roughly spherical N-monopole that has more than N zeros of the Higgs field. We introduce an extension of the magnetic bag that does provide a good approximation to such monopoles and involves a spherical non-abelian interior for the bag, in addition to the conventional abelian exterior.

  17. Superconductivity and Magnetism: Materials Properties

    E-Print Network [OSTI]

    .g. within high-Tc superconductivity, magnetic superconductors, MgB2, CMR materials, nanomagnetism and spin#12;#12;Superconductivity and Magnetism: Materials Properties and Developments #12;Copyright 2003 Risø National Laboratory Roskilde, Denmark ISBN 87-550-3244-3 ISSN 0907-0079 #12;Superconductivity

  18. Magnetic Resonance Facility (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-03-01T23:59:59.000Z

    This fact sheet provides information about Magnetic Resonance Facility capabilities and applications at NREL's National Bioenergy Center. Liquid and solid-state analysis capability for a variety of biomass, photovoltaic, and materials characterization applications across NREL. NREL scientists analyze solid and liquid samples on three nuclear magnetic resonance (NMR) spectrometers as well as an electron paramagnetic resonance (EPR) spectrometer.

  19. NANOSCALE STRUCTURALAND MAGNETIC CHARACTERIZATION USING

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    of novel nanoscale storage devices and sensors. However, for successful utilization, it is essential]. Such unique properties of magnetic thin films and nanostructures hold great promise for the development to the characterization of nanostructured magnetic materials. 2. ELECTRON MICROSCOPY METHODS In the transmission electron

  20. Plated lamination structures for integrated magnetic devices

    SciTech Connect (OSTI)

    Webb, Bucknell C.

    2014-06-17T23:59:59.000Z

    Semiconductor integrated magnetic devices such as inductors, transformers, etc., having laminated magnetic-insulator stack structures are provided, wherein the laminated magnetic-insulator stack structures are formed using electroplating techniques. For example, an integrated laminated magnetic device includes a multilayer stack structure having alternating magnetic and insulating layers formed on a substrate, wherein each magnetic layer in the multilayer stack structure is separated from another magnetic layer in the multilayer stack structure by an insulating layer, and a local shorting structure to electrically connect each magnetic layer in the multilayer stack structure to an underlying magnetic layer in the multilayer stack structure to facilitate electroplating of the magnetic layers using an underlying conductive layer (magnetic or seed layer) in the stack as an electrical cathode/anode for each electroplated magnetic layer in the stack structure.