Science.gov

Sample records for faraday fast track

  1. Fast Faraday Cup With High Bandwidth

    DOEpatents

    Deibele, Craig E [Knoxville, TN

    2006-03-14

    A circuit card stripline Fast Faraday cup quantitatively measures the picosecond time structure of a charged particle beam. The stripline configuration maintains signal integrity, and stitching of the stripline increases the bandwidth. A calibration procedure ensures the measurement of the absolute charge and time structure of the charged particle beam.

  2. Fast tracking hospital construction.

    PubMed

    Quirk, Andrew

    2013-03-01

    Hospital leaders should consider four factors in determining whether to fast track a hospital construction project: Expectations of project length, quality, and cost. Whether decisions can be made quickly as issues arise. Their own time commitment to the project, as well as that of architects, engineers, construction managers, and others. The extent to which they are willing to share with the design and construction teams how and why decisions are being made.

  3. Fast Track Study

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The NASA Fast Track Study supports the efforts of a Special Study Group (SSG) made up of members of the Advanced Project Management Class number 23 (APM-23) that met at the Wallops Island Management Education Center from April 28 - May 8, 1996. Members of the Class expressed interest to Mr. Vem Weyers in having an input to the NASA Policy Document (NPD) 7120.4, that will replace NASA Management Institute (NMI) 7120.4, and the NASA Program/Project Management Guide. The APM-23 SSG was tasked with assisting in development of NASA policy on managing Fast Track Projects, defined as small projects under $150 million and completed within three years. 'Me approach of the APM-23 SSG was to gather data on successful projects working in a 'Better, Faster, Cheaper' environment, within and outside of NASA and develop the Fast Track Project section of the NASA Program/Project Management Guide. Fourteen interviews and four other data gathering efforts were conducted by the SSG, and 16 were conducted by Strategic Resources, Inc. (SRI), including five interviews at the Jet Propulsion Laboratory (JPL) and one at the Applied Physics Laboratory (APL). The interviews were compiled and analyzed for techniques and approaches commonly used to meet severe cost and schedule constraints.

  4. Fast Faraday fading of long range satellite signals.

    NASA Technical Reports Server (NTRS)

    Heron, M. L.

    1972-01-01

    20 MHz radio signals have been received during the day from satellite Beacon-B when it was below the optical horizon by using a bank of narrow filters to improve the signal to noise ratio. The Faraday fading rate becomes constant, under these conditions, at a level determined by the plasma frequency just below the F-layer peak. Variations in the Faraday fading rate reveal fluctuations in the electron density near the peak, while the rate of attaining the constant level depends on the shape of the electron density profile.

  5. Fast-Tracking Colostomy Closures.

    PubMed

    Nanavati, Aditya J; Prabhakar, Subramaniam

    2015-12-01

    There have been very few studies on applying fast-track principles to colostomy closures. We believe that outcome may be significantly improved with multimodal interventions in the peri-operative care of patients undergoing this procedure. A retrospective study was carried out comparing patients who had undergone colostomy closures by the fast-track and traditional care protocols at our centre. We intended to analyse peri-operative period and recovery in colostomy closures to confirm that fast-track surgery principles improved outcomes. Twenty-six patients in the fast-track arm and 24 patients in the traditional care arm had undergone colostomy closures. Both groups were comparable in terms of their baseline parameters. Patients in the fast-track group were ambulatory and accepted oral feeding earlier. There was a significant reduction in the duration of stay (4.73 ± 1.43 days vs. 7.21 ± 1.38 days, p = 0.0000). We did not observe a rise in complications or 30-day re-admissions. Fast-track surgery can safely be applied to colostomy closures. It shows earlier ambulation and reduction in length of hospital stay.

  6. Faraday-cup-type lost fast ion detector on Heliotron J.

    PubMed

    Yamamoto, S; Ogawa, K; Isobe, M; Darrow, D S; Kobayashi, S; Nagasaki, K; Okada, H; Minami, T; Kado, S; Ohshima, S; Weir, G M; Nakamura, Y; Konoshima, S; Kemmochi, N; Ohtani, Y; Mizuuchi, T

    2016-11-01

    A Faraday-cup type lost-fast ion probe (FLIP) has been designed and installed in Heliotron J for the purpose of the studies of interaction between fast ions and MHD instabilities. The FLIP can measure the co-going fast ions whose energy is in the range of 1.7-42.5 keV (proton) and pitch angle of 90(∘)-140(∘), especially for fast ions having the injection energy of neutral beam injection (NBI). The FLIP successfully measured the re-entering passing ions and trapped lost-fast ions caused by fast-ion-driven energetic particle modes in NBI heated plasmas.

  7. Parasitic excitation of ion Bernstein waves from a Faraday shielded fast wave loop antenna

    SciTech Connect

    Skiff, F.; Ono, M.; Colestock, P.; Wong, K.L.

    1984-12-01

    Parasitic excitation of ion Bernstein waves is observed from a Faraday shielded fast wave loop antenna in the ion cyclotron frequency range. Local analysis of the Vlasov-Maxwell equations demonstrates the role of plasma density gradient in the coupling process. The effects of plasma density and of parallel wave number on the excitation process are investigated.

  8. Stripline fast faraday cup for measuring GHz structure of ion beams

    DOEpatents

    Bogaty, John M.

    1992-01-01

    The Stripline Fast Faraday Cup is a device which is used to quantitatively and qualitatively measure gigahertz time structure characteristics of ion beams with energies up to at least 30 Mev per nucleon. A stripline geometry is employed in conjunction with an electrostatic screen and a Faraday cup to provide for analysis of the structural characteristics of an ion beam. The stripline geometry allows for a large reduction in the size of the instrument while the electrostatic screen permits measurements of the properties associated with low speed ion beams.

  9. Fast track to 340B.

    PubMed

    Gricius, Robert F; Wong, Douglas

    2016-01-01

    Hospitals that are newly qualified for the 340B Drug Pricing Program may have an opportunity for fast-track approval to participate in the program. Three steps are required to seize this opportunity: Use data analytics to assess current and future percentages of Medicaid utilization and eligibility for federal SSI cash benefits. Determine the feasibility of early cost report filing. Prepare appropriate documentation and undertake the initial enrollment process.

  10. A tracking polarimeter for measuring solar and ionospheric Faraday rotation of signals from deep space probes

    NASA Technical Reports Server (NTRS)

    Ohlson, J. E.; Levy, G. S.; Stelzried, C. T.

    1974-01-01

    A tracking polarimeter implemented on the 64-m NASA/JPL paraboloid antenna at Goldstone, Calif., is described. Its performance is analyzed and compared with measurements. The system was developed to measure Faraday rotation in the solar corona of the telemetry carrier from the Pioneer VI spacecraft as it was occulted by the sun. It also measures rotation in the earth's ionosphere and is an accurate method of determining spacecraft orientation. The new feature of this system is its use of a pair of quarter-wave plates to allow the synthesis of a rotating feed system, while requiring the rotation of only a single section of waveguide. Since the polarization sensing is done at RF and the receiver operates essentially as a null detector, the system's accuracy is superior to other polarization tracking schemes. In addition, the antenna size and maser preamplifier provide unsurpassed sensitivity. The associated instrumentation used in the Pioneer VI experiment is also described.

  11. Fast sweep-rate plastic Faraday force magnetometer with simultaneous sample temperature measurement.

    PubMed

    Slobinsky, D; Borzi, R A; Mackenzie, A P; Grigera, S A

    2012-12-01

    We present a design for a magnetometer capable of operating at temperatures down to 50 mK and magnetic fields up to 15 T with integrated sample temperature measurement. Our design is based on the concept of a Faraday force magnetometer with a load-sensing variable capacitor. A plastic body allows for fast sweep rates and sample temperature measurement, and the possibility of regulating the initial capacitance simplifies the initial bridge balancing. Under moderate gradient fields of ~1 T/m our prototype performed with a resolution better than 1 × 10(-5) emu. The magnetometer can be operated either in a dc mode, or in an oscillatory mode which allows the determination of the magnetic susceptibility. We present measurements on Dy(2)Ti(2)O(7) and Sr(3)Ru(2)O(7) as an example of its performance.

  12. The Physics of Fast Track

    ERIC Educational Resources Information Center

    Kibble, Bob

    2007-01-01

    Toys can provide motivational contexts for learning and teaching about physics. A cheap car track provides an almost frictionless environment from which a quantitative study of conservation of energy and circular motion can be made.

  13. Math on the Fast Track

    ERIC Educational Resources Information Center

    Howe, Quincy

    2006-01-01

    In this article, the author relates how a math-assessment software has allowed his school to track the academic progress of its students. The author relates that in the first year that the software was deployed, schoolwide averages in terms of national standing on the math ITBS rose from the 42nd to 59th percentile. In addition, a significant…

  14. Faraday cup with nanosecond response and adjustable impedance for fast electron beam characterization.

    PubMed

    Hu, Jing; Rovey, Joshua L

    2011-07-01

    A movable Faraday cup design with simple structure and adjustable impedance is described in this work. This Faraday cup has external adjustable shunt resistance for self-biased measurement setup and 50 Ω characteristic impedance to match with 50 Ω standard BNC coaxial cable and vacuum feedthroughs for nanosecond-level pulse signal measurements. Adjustable shunt resistance allows self-biased measurements to be quickly acquired to determine the electron energy distribution function. The performance of the Faraday cup is validated by tests of response time and amplitude of output signal. When compared with a reference source, the percent difference of the Faraday cup signal fall time is less than 10% for fall times greater than 10 ns. The percent difference of the Faraday cup signal pulse width is below 6.7% for pulse widths greater than 10 ns. A pseudospark-generated electron beam is used to compare the amplitude of the Faraday cup signal with a calibrated F-70 commercial current transformer. The error of the Faraday cup output amplitude is below 10% for the 4-14 kV tested pseudospark voltages. The main benefit of this Faraday cup is demonstrated by adjusting the external shunt resistance and performing the self-biased method for obtaining the electron energy distribution function. Results from a 4 kV pseudospark discharge indicate a "double-humped" energy distribution.

  15. Accelerated Leadership Development: Fast Tracking School Leaders

    ERIC Educational Resources Information Center

    Earley, Peter; Jones, Jeff

    2010-01-01

    "Accelerated Leadership Development" captures and communicates the lessons learned from successful fast-track leadership programmes in the private and public sector, and provides a model which schools can follow and customize as they plan their own leadership development strategies. As large numbers of headteachers and other senior staff…

  16. FATRAS - the ATLAS Fast Track Simulation project

    NASA Astrophysics Data System (ADS)

    Mechnich, Jörg; ATLAS Collaboration

    2011-12-01

    The Monte Carlo simulation of the detector response is an integral component of any analysis performed with data from the LHC experiments. As these simulated data sets must be both large and precise, their production is a CPU-intensive task. ATLAS has developed full and fast detector simulation techniques to achieve this goal within the computing limits of the collaboration. At the current early stages of data-taking, it is necessary to reprocess the Monte Carlo event samples continuously, while integrating adaptations to the simulation modules in order to improve the agreement with data taken by means of the detector itself. FATRAS is a fast track simulation engine which produces a Monte Carlo simulation based on modules and the geometry of the standard ATLAS track reconstruction algorithm. It can be combined with a fast parametrized-response simulation of the calorimeters. This approach shows a high level of agreement with the full simulation, while achieving a relative timing gain of two orders of magnitude. FATRAS was designed to provide a fast feedback cycle for tuning the MC simulation with real data: this includes the material distribution inside the detector, the integration of misalignment and current conditions, as well as calibration at the hit level. We present the updated and calibrated version of FATRAS based on the first LHC data. Extensive comparisons of the fast track simulation with the full simulation and data at 900 GeV are shown.

  17. 40 CFR 72.82 - Fast-track modifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Fast-track modifications. 72.82... (CONTINUED) PERMITS REGULATION Permit Revisions § 72.82 Fast-track modifications. The following procedures shall apply to all fast-track modifications. (a) If the Administrator is the permitting authority,...

  18. 40 CFR 72.82 - Fast-track modifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Fast-track modifications. 72.82... (CONTINUED) PERMITS REGULATION Permit Revisions § 72.82 Fast-track modifications. The following procedures shall apply to all fast-track modifications. (a) If the Administrator is the permitting authority,...

  19. ``Fast Track'' nuclear thermal propulsion concept

    NASA Astrophysics Data System (ADS)

    Johnson, Richard A.; Zweig, Herbert R.; Cooper, Martin H.; Wett, Jack

    1993-01-01

    The objective of the Space Exploration Initiative (``America at the Threshold...,'' 1991) is the exploration of Mars by man in the second decade of the 21st century. The NASA ``Fast Track'' approach (NASA-LeRC Presentation, 1992) could accelerate the manned exploration of Mars to 2007. NERVA-derived nuclear propulsion represents a viable near-term technology approach to accomplish the accelerated schedule. Key milestones in the progression to the manned Mars mission are (1) demonstration of TRL-6 for the man-rateable system by 1999, (2) a robotic lunar mission by 2000, (3) the first cargo mission to Mars by 2005, and (4) the piloted Mars mission in 2007. The Rocketdyne-Westinghouse concept for nuclear thermal propulsion to achieve these milestones combines the nuclear reactor technology of the Rover/NERVA programs and the state-of-the-art hardware designs from hydrogen-fueled rocket engine successes like the Space Shuttle Main Engine (SSME).

  20. Security market reaction to FDA fast track designations.

    PubMed

    Anderson, Christopher W; Zhang, Ying

    2010-01-01

    Pharmaceutical firms can apply for the Food and Drug Administration to 'fast track' research and de velopment on new drugs, accelerating clinical trials and expediting regulatory review required prior to marketing to consumers. We investigate security market reaction to more than 100 fast track designations from 1998 to 2004. Fast track designation appears to enhance investor recognition of firm value. Specifically, fast track designation coincides with abnormal trading volume and excess daily stock returns for sponsoring firms. Institutional ownership and analyst attention also increase. Market response is more pronounced for firms that are smaller, do not yet market products, and have low institutional ownership.

  1. Design and Construction of a Fast Ion Loss Faraday Cup Array Diagnostic for JET

    SciTech Connect

    D.S. Darrow; S. Bauumel; F.E. Cecil; V. Kiptily; R. Ellis; L. Pedrick; A. Werner

    2004-04-26

    A thin foil Faraday cup array is being built to measure the loss of 3.5 MeV alpha particles and MeV ion cyclotron heating (ICH) tail ions on JET. It will consist of nine detectors spread over five different poloidal locations and three radial positions. They will measure the poloidal distribution and radial scrape off of the losses. The detectors will be comprised of four layers of thin (2.5 micron) Ni foil, giving some resolution of the lost particle energy distribution as different ranges of energies will stop in different layers of the detector. One detector will utilize eight thinner (1.0 micron) foils to obtain a better resolved energy distribution. These detectors will accept particles incident up to 45{sup o} from the normal to the foils.

  2. Fast Track: A Language Arts Program for Middle School Gifted

    ERIC Educational Resources Information Center

    Schneider, Jean

    2008-01-01

    "Fast Track" is a pseudonym for an accelerated, advanced language arts program for verbally gifted and high potential students in grades 6-8. The critical thinking model used for "Fast Track" was gleaned from Coalition of Essential Schools founder Ted Sizer's Habits of Mind: significance, evidence, connections, perspective, and supposition, as…

  3. Fast Track Teaching: Beginning the Experiment in Accelerated Leadership Development

    ERIC Educational Resources Information Center

    Churches, Richard; Hutchinson, Geraldine; Jones, Jeff

    2009-01-01

    This article provides an overview of the development of the Fast Track teaching programme and personalised nature of the training and support that has been delivered. Fast Track teacher promotion rates are compared to national statistics demonstrating significant progression for certain groups, particularly women. (Contains 3 tables and 3 figures.)

  4. Detection of nitro-based and peroxide-based explosives by fast polarity-switchable ion mobility spectrometer with ion focusing in vicinity of Faraday detector.

    PubMed

    Zhou, Qinghua; Peng, Liying; Jiang, Dandan; Wang, Xin; Wang, Haiyan; Li, Haiyang

    2015-05-29

    Ion mobility spectrometer (IMS) has been widely deployed for on-site detection of explosives. The common nitro-based explosives are usually detected by negative IMS while the emerging peroxide-based explosives are better detected by positive IMS. In this study, a fast polarity-switchable IMS was constructed to detect these two explosive species in a single measurement. As the large traditional Faraday detector would cause a trailing reactant ion peak (RIP), a Faraday detector with ion focusing in vicinity was developed by reducing the detector radius to 3.3 mm and increasing the voltage difference between aperture grid and its front guard ring to 591 V, which could remove trailing peaks from RIP without loss of signal intensity. This fast polarity-switchable IMS with ion focusing in vicinity of Faraday detector was employed to detect a mixture of 10 ng 2,4,6-trinitrotoluene (TNT) and 50 ng hexamethylene triperoxide diamine (HMTD) by polarity-switching, and the result suggested that [TNT-H](-) and [HMTD+H](+) could be detected in a single measurement. Furthermore, the removal of trailing peaks from RIP by the Faraday detector with ion focusing in vicinity also promised the accurate identification of KClO4, KNO3 and S in common inorganic explosives, whose product ion peaks were fairly adjacent to RIP.

  5. TRACKING TESTS FOR THE SNS FAST INJECTION BUMP POWER SUPPLY

    SciTech Connect

    ENG,W.CUTLER,R.DEWAN,S.ET AL.

    2004-07-05

    The tracking requirement of the SNS Fast Injection Bump power supplies is described. In addition to the usual tracking between the load current and the input reference of a power supply, these power supplies must also track between pairs of units under slightly different loads. This paper describes the use of a current-null test to measure tracking performances. For the actual tests, a single dummy magnet load was used to measure the tracking between the first two production units at the manufacturer's facility. Using the Yokogawa WE7000 waveform. PC-based measurement instrument, input and output waveforms are digitized and stored in data files. A program written for this application is then used to extract data from these files to construct, analyze the waveforms and characterize the power supply performance. Results of the measurements of two SNS Fast Injection Bump power supplies will be presented in this paper.

  6. Fast Markerless Tracking for Augmented Reality in Planar Environment

    NASA Astrophysics Data System (ADS)

    Basori, Ahmad Hoirul; Afif, Fadhil Noer; Almazyad, Abdulaziz S.; AbuJabal, Hamza Ali S.; Rehman, Amjad; Alkawaz, Mohammed Hazim

    2015-12-01

    Markerless tracking for augmented reality should not only be accurate but also fast enough to provide a seamless synchronization between real and virtual beings. Current reported methods showed that a vision-based tracking is accurate but requires high computational power. This paper proposes a real-time hybrid-based method for tracking unknown environments in markerless augmented reality. The proposed method provides collaboration of vision-based approach with accelerometers and gyroscopes sensors as camera pose predictor. To align the augmentation relative to camera motion, the tracking method is done by substituting feature-based camera estimation with combination of inertial sensors with complementary filter to provide more dynamic response. The proposed method managed to track unknown environment with faster processing time compared to available feature-based approaches. Moreover, the proposed method can sustain its estimation in a situation where feature-based tracking loses its track. The collaboration of sensor tracking managed to perform the task for about 22.97 FPS, up to five times faster than feature-based tracking method used as comparison. Therefore, the proposed method can be used to track unknown environments without depending on amount of features on scene, while requiring lower computational cost.

  7. Fast Track: Elementary School. What Works Clearinghouse Intervention Report

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2014

    2014-01-01

    "Fast Track" is a comprehensive intervention designed to reduce conduct problems and promote academic, behavioral, and social improvement. The program's components include the "Promoting Alternative THinking Strategies" curriculum, parent groups, parent-child sharing time, child social skills training, home visiting, child…

  8. Fast-Track Cleanup at Closing DoD Installations

    EPA Pesticide Factsheets

    The Fast-Track Cleanup program strives to make parcels available for reuse as quickly as possible by the transfer of uncontaminated or remediated parcels, the lease of contaminated parcels where cleanup is underway, or the 'early transfer' of contaminated property undergoing cleanup.

  9. Teacher Perspectives on Their Alternative Fast-Track Induction

    ERIC Educational Resources Information Center

    Haim, Orly; Amdur, Lisa

    2016-01-01

    The purpose of this study was to explore the professional challenges and concerns of 30 second career teachers (SCTs) participating in an alternative fast-track induction program during their first year of teaching. Additionally, the study investigated their perspectives of the institutional support provided to them. The main source of data was…

  10. Fast Track to Success: Top Young Trainers 2012

    ERIC Educational Resources Information Center

    Freifeld, Lorri

    2012-01-01

    Supercharged. High-performers. Leaders of the pack. This article presents "Training" magazine's 2012 Top Young Trainers--those high-potential training professionals who are on the fast track to success. For the fifth year, "Training" magazine is pleased to recognize the outstanding talents, accomplishments, and leadership exhibited by 40 learning…

  11. Education For All (EFA) - Fast Track Initiative Progress Report 30046

    ERIC Educational Resources Information Center

    World Bank Education Advisory Service, 2004

    2004-01-01

    Launched in June 2002, the Education For All-Fast Track Initiative (FTI) is a performance-based program focusing on the implementation of sustainable policies in support of universal primary completion (UPC) and the required resource mobilization. During its twenty months of implementation, FTI has delivered on results, which give reason for…

  12. 4D fast tracking for experiments at high luminosity LHC

    NASA Astrophysics Data System (ADS)

    Neri, N.; Cardini, A.; Calabrese, R.; Fiorini, M.; Luppi, E.; Marconi, U.; Petruzzo, M.

    2016-11-01

    The full exploitation of the physics potential of the high luminosity LHC is a big challenge that requires new instrumentation and innovative solutions. We present here a conceptual design and simulation studies of a fast timing pixel detector with embedded real-time tracking capabilities. The system is conceived to operate at 40 MHz event rate and to reconstruct tracks in real-time, using precise space and time 4D information of the hit, for fast trigger decisions. This work is part of an R&D project aimed at building an innovative tracking detector with superior time (10 ps) and position (10 μm) resolutions to be used in very harsh radiation environments, for the ultimate flavour physics experiment at the high luminosity phase of the LHC.

  13. Fast left ventricle tracking using localized anatomical affine optical flow.

    PubMed

    Queirós, Sandro; Vilaça, João L; Morais, Pedro; Fonseca, Jaime C; D'hooge, Jan; Barbosa, Daniel

    2017-02-16

    In daily clinical cardiology practice, left ventricle (LV) global and regional function assessment is crucial for disease diagnosis, therapy selection and patient follow-up. Currently, this is still a time-consuming task, spending valuable human resources. In this work, a novel fast methodology for automatic LV tracking is proposed based on localized anatomically constrained affine optical flow. This novel method can be combined to previously proposed segmentation frameworks or manually delineated surfaces at an initial frame to obtain fully delineated datasets and, thus, assess both global and regional myocardial function. Its feasibility and accuracy was investigated in three distinct public databases, namely in realistically simulated 3D ultrasound (US), clinical 3D echocardiography and clinical cine cardiac magnetic resonance (CMR) images. The method showed accurate tracking results in all databases, proving its applicability and accuracy for myocardial function assessment. Moreover, when combined to previous state-of-the-art segmentation frameworks, it outperformed previous tracking strategies in both 3D US and CMR data, automatically computing relevant cardiac indices with smaller biases and narrower limits of agreement compared to reference indices. Simultaneously, the proposed localized tracking method showed to be suitable for online processing, even for 3D motion assessment. Importantly, although here evaluated for LV tracking only, this novel methodology is applicable for tracking of other target structures with minimal adaptations. This article is protected by copyright. All rights reserved.

  14. Fast-track drug approval in inflammatory bowel diseases

    PubMed Central

    Katsanos, Konstantinos H.; Koutroumpakis, Efstratios; Giagkou, Eftychia; Malakos, Zikos; Almpani, Eleni; Skamnelos, Alexandros; Christodoulou, Dimitrios K.

    2016-01-01

    Fast-track drug designation of safe regimens represents an emerging method of development and approval of new medications targeting debilitating diseases including inflammatory bowel diseases (IBD). The goal of accelerated drug approval pathways is to shorten the time between application and approval of therapies that treat diseases with significant morbidity and mortality. Recently, fast-track drug approval approaches were supported by data deriving from central reading of images, a method of clinical data interpretation that has significantly benefited patients with gastrointestinal disorders. Biological agents and other emerging therapies in IBD represent “game-changing” or “treat-to-target” drugs and have satisfied quite successfully some of the patients’ unmet needs. The development of biosimilars is an area where the Federal Drug Administration and the European Agency for Evaluation of Medicinal Products seem to have different approval processes. Biosimilars, including those for IBD, promise cost reductions and wide access to biologic therapies by patients, advantages similar to those already offered by generic drugs. Given the rapid development of IBD drugs and patients’ needs, a consensus among the academic community, clinicians, researchers, sponsors, patients and regulatory authorities is required to standardize better the IBD trials and create a productive environment for fast-track approval of any “changing-game” IBD drug. PMID:27708508

  15. A Midsize Tokamak As Fast Track To Burning Plasmas

    SciTech Connect

    E. Mazzucato

    2010-07-14

    This paper presents a midsize tokamak as a fast track to the investigation of burning plasmas. It is shown that it could reach large values of energy gain (≥10) with only a modest improvement in confinement over the scaling that was used for designing the International Thermonuclear Experimental Reactor (ITER). This could be achieved by operating in a low plasma recycling regime that experiments indicate can lead to improved plasma confinement. The possibility of reaching the necessary conditions of low recycling using a more efficient magnetic divertor than those of present tokamaks is discussed.

  16. Ultra-Fast Silicon Detectors for 4D tracking

    NASA Astrophysics Data System (ADS)

    Sola, V.; Arcidiacono, R.; Bellora, A.; Cartiglia, N.; Cenna, F.; Cirio, R.; Durando, S.; Ferrero, M.; Galloway, Z.; Gruey, B.; Freeman, P.; Mashayekhi, M.; Mandurrino, M.; Monaco, V.; Mulargia, R.; Obertino, M. M.; Ravera, F.; Sacchi, R.; Sadrozinski, H. F.-W.; Seiden, A.; Spencer, N.; Staiano, A.; Wilder, M.; Woods, N.; Zatserklyaniy, A.

    2017-02-01

    We review the progress toward the development of a novel type of silicon detectors suited for tracking with a picosecond timing resolution, the so called Ultra-Fast Silicon Detectors. The goal is to create a new family of particle detectors merging excellent position and timing resolution with GHz counting capabilities, very low material budget, radiation resistance, fine granularity, low power, insensitivity to magnetic field, and affordability. We aim to achieve concurrent precisions of ~ 10 ps and ~ 10 μm with a 50 μm thick sensor. Ultra-Fast Silicon Detectors are based on the concept of Low-Gain Avalanche Detectors, which are silicon detectors with an internal multiplication mechanism so that they generate a signal which is factor ~ 10 larger than standard silicon detectors.

  17. X-33 Environmental Impact Statement: A Fast Track Approach

    NASA Technical Reports Server (NTRS)

    McCaleb, Rebecca C.; Holland, Donna L.

    1998-01-01

    NASA is required by the National Environmental Policy Act (NEPA) to prepare an appropriate level environmental analysis for its major projects. Development of the X-33 Technology Demonstrator and its associated flight test program required an environmental impact statement (EIS) under the NEPA. The EIS process is consists of four parts: the "Notice of Intent" to prepare an EIS and scoping; the draft EIS which is distributed for review and comment; the final ETS; and the "Record of Decision." Completion of this process normally takes from 2 - 3 years, depending on the complexity of the proposed action. Many of the agency's newest fast track, technology demonstration programs require NEPA documentation, but cannot sustain the lengthy time requirement between program concept development to implementation. Marshall Space Flight Center, in cooperation with Kennedy Space Center, accomplished the NEPA process for the X-33 Program in 13 months from Notice of Intent to Record of Decision. In addition, the environmental team implemented an extensive public involvement process, conducting a total of 23 public meetings for scoping and draft EIS comment along with numerous informal meetings with public officials, civic organizations, and Native American Indians. This paper will discuss the fast track approach used to successfully accomplish the NEPA process for X-33 on time.

  18. Fast Track intervention effects on youth arrests and delinquency

    PubMed Central

    2010-01-01

    This paper examines the effects of the Fast Track preventive intervention on youth arrests and self-reported delinquent behavior through age 19. High-risk youth randomly assigned to receive a long-term, comprehensive preventive intervention from 1st grade through 10th grade at four sites were compared to high-risk control youth. Findings indicated that random assignment to Fast Track reduced court-recorded juvenile arrest activity based on a severity weighted sum of juvenile arrests. Supplementary analyses revealed an intervention effect on the reduction in the number of court-recorded moderate-severity juvenile arrests, relative to control children. In addition, among youth with higher initial behavioral risk, the intervention reduced the number of high-severity adult arrests relative to the control youth. Survival analyses examining the onset of arrests and delinquent behavior revealed a similar pattern of findings. Intervention decreased the probability of any juvenile arrest among intervention youth not previously arrested. In addition, intervention decreased the probability of a self-reported high-severity offense among youth with no previous self-reported high-severity offense. Intervention effects were also evident on the onset of high-severity court-recorded adult arrests among participants, but these effects varied by site. The current findings suggest that comprehensive preventive intervention can prevent juvenile arrest rates, although the presence and nature of intervention effects differs by outcome. PMID:20577576

  19. Fast regional readout CMOS Image Sensor for dynamic MLC tracking

    NASA Astrophysics Data System (ADS)

    Zin, H.; Harris, E.; Osmond, J.; Evans, P.

    2014-03-01

    Advanced radiotherapy techniques such as volumetric modulated arc therapy (VMAT) require verification of the complex beam delivery including tracking of multileaf collimators (MLC) and monitoring the dose rate. This work explores the feasibility of a prototype Complementary metal-oxide semiconductor Image Sensor (CIS) for tracking these complex treatments by utilising fast, region of interest (ROI) read out functionality. An automatic edge tracking algorithm was used to locate the MLC leaves edges moving at various speeds (from a moving triangle field shape) and imaged with various sensor frame rates. The CIS demonstrates successful edge detection of the dynamic MLC motion within accuracy of 1.0 mm. This demonstrates the feasibility of the sensor to verify treatment delivery involving dynamic MLC up to ~400 frames per second (equivalent to the linac pulse rate), which is superior to any current techniques such as using electronic portal imaging devices (EPID). CIS provides the basis to an essential real-time verification tool, useful in accessing accurate delivery of complex high energy radiation to the tumour and ultimately to achieve better cure rates for cancer patients.

  20. Fast-Acquisition/Weak-Signal-Tracking GPS Receiver for HEO

    NASA Technical Reports Server (NTRS)

    Wintemitz, Luke; Boegner, Greg; Sirotzky, Steve

    2004-01-01

    A report discusses the technical background and design of the Navigator Global Positioning System (GPS) receiver -- . a radiation-hardened receiver intended for use aboard spacecraft. Navigator is capable of weak signal acquisition and tracking as well as much faster acquisition of strong or weak signals with no a priori knowledge or external aiding. Weak-signal acquisition and tracking enables GPS use in high Earth orbits (HEO), and fast acquisition allows for the receiver to remain without power until needed in any orbit. Signal acquisition and signal tracking are, respectively, the processes of finding and demodulating a signal. Acquisition is the more computationally difficult process. Previous GPS receivers employ the method of sequentially searching the two-dimensional signal parameter space (code phase and Doppler). Navigator exploits properties of the Fourier transform in a massively parallel search for the GPS signal. This method results in far faster acquisition times [in the lab, 12 GPS satellites have been acquired with no a priori knowledge in a Low-Earth-Orbit (LEO) scenario in less than one second]. Modeling has shown that Navigator will be capable of acquiring signals down to 25 dB-Hz, appropriate for HEO missions. Navigator is built using the radiation-hardened ColdFire microprocessor and housing the most computationally intense functions in dedicated field-programmable gate arrays. The high performance of the algorithm and of the receiver as a whole are made possible by optimizing computational efficiency and carefully weighing tradeoffs among the sampling rate, data format, and data-path bit width.

  1. "Fast Track" and "Traditional Path" Coaches: Affordances, Agency and Social Capital

    ERIC Educational Resources Information Center

    Rynne, Steven

    2014-01-01

    A recent development in large-scale coach accreditation (certification) structures has been the "fast tracking" of former elite athletes. Former elite athletes are often exempted from entry-level qualifications and are generally granted access to fast track courses that are shortened versions of the accreditation courses undertaken by…

  2. Fast TracKer: A fast hardware track trigger for the ATLAS detector

    NASA Astrophysics Data System (ADS)

    Pandini, Carlo

    2016-07-01

    The trigger system at the ATLAS experiment is designed to lower the event rate occurring from the nominal bunch crossing rate of 40 MHz to about 1 kHz for a LHC luminosity of the order of 1034cm-2s-1. To achieve high background rejection while maintaining good efficiency for interesting physics signals, sophisticated algorithms are needed which require an extensive use of tracking information. The Fast TracKer (FTK) trigger system, part of the ATLAS trigger upgrade program, is a highly parallel hardware device designed to perform track-finding at 100 kHz. Modern, powerful Field Programmable Gate Arrays (FPGAs) form an important part of the system architecture, and the combinatorial problem of pattern recognition is solved by 8000 standard-cell ASICs used to implement an Associative Memory architecture. The availability of the tracking and subsequent vertex information within a short latency ensures robust selections and allows improved trigger performance for the most difficult signatures, such as b-jets and τ leptons.

  3. Semisynthetic photoprotein reporters for tracking fast Ca(2+) transients.

    PubMed

    Malikova, Natalia P; Borgdorff, Aren J; Vysotski, Eugene S

    2015-12-01

    Changes in the intracellular concentration of free ionized calcium ([Ca(2+)]i) control a host of cellular processes as varied as vision, muscle contraction, neuronal signal transmission, proliferation, apoptosis etc. The disturbance in Ca(2+)-signaling causes many severe diseases. To understand the mechanisms underlying the control by calcium and how disorder of this regulation relates to pathological conditions, it is necessary to measure [Ca(2+)]i. The Ca(2+)-regulated photoproteins which are responsible for bioluminescence of marine coelenterates have been successfully used for this purpose over the years. Here we report the results on comparative characterization of bioluminescence properties of aequorin from Aequorea victoria, obelin from Obelia longissima, and clytin from Clytia gregaria charged by native coelenterazine and coelenterazine analogues f, i, and hcp. The comparison of specific bioluminescence activity, stability, emission spectra, stopped-flow kinetics, sensitivity to calcium, and effect of physiological concentrations of Mg(2+) establishes obelin-hcp as an excellent semisynthetic photoprotein to keep track of fast intracellular Ca(2+) transients. The rate of rise of its light signal on a sudden change of [Ca(2+)] is almost 3- and 11-fold higher than those of obelin and aequorin with native coelenterazine, respectively, and 20 times higher than that of the corresponding aequorin-hcp. In addition, obelin-hcp preserves a high specific bioluminescence activity and displays higher Ca(2+)-sensitivity as compared to obelin charged by native coelenterazine and sensitivity to Ca(2+) comparable with those of aequorin-f and aequorin-hcp.

  4. Making an ED fast track exactly that--fast and efficient.

    PubMed

    Guido, Kathy

    2007-01-01

    Medical facilities must streamline their processes if they want to maintain quality care while reducing costs. In 2005, Benedictine Hospital's struggle to operate more productively, efficiently, and profitably dissipated when it streamlined the administrative process of billing patients for chemotherapy treatments. In 2006, it applied similar changes to effectively treat patients while efficiently processing them through its fast track emergency department. Over the last two decades, The Hudson Valley Technology Development Center (HVTDC) has worked primarily with manufacturing- and technology-based companies to help them adopt new business practices in order to grow and to work more efficiently, effectively, and profitably by streamlining daily operations. In recent years, HVTDC has chosen to introduce the long-established and widely proven principles of lean manufacturing to medical facilities.

  5. 42 CFR 422.626 - Fast-track appeals of service terminations to independent review entities (IREs).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Fast-track appeals of service terminations to... Grievances, Organization Determinations and Appeals § 422.626 Fast-track appeals of service terminations to independent review entities (IREs). (a) Enrollee's right to a fast-track appeal of an MA...

  6. 42 CFR 422.626 - Fast-track appeals of service terminations to independent review entities (IREs).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Fast-track appeals of service terminations to... Grievances, Organization Determinations and Appeals § 422.626 Fast-track appeals of service terminations to independent review entities (IREs). (a) Enrollee's right to a fast-track appeal of an MA...

  7. Fast polarization-state tracking scheme based on radius-directed linear Kalman filter.

    PubMed

    Yang, Yanfu; Cao, Guoliang; Zhong, Kangping; Zhou, Xian; Yao, Yong; Lau, Alan Pak Tao; Lu, Chao

    2015-07-27

    We propose and experimentally demonstrate a fast polarization tracking scheme based on radius-directed linear Kalman filter. It has the advantages of fast convergence and is inherently insensitive to phase noise and frequency offset effects. The scheme is experimentally compared to conventional polarization tracking methods on the polarization rotation angular frequency. The results show that better tracking capability with more than one order of magnitude improvement is obtained in the cases of polarization multiplexed QPSK and 16QAM signals. The influences of the filter tuning parameters on tracking performance are also investigated in detail.

  8. 77 FR 1697 - Agency Information Collection Activities: Fast Track Generic Clearance for the Collection of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-11

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Indian Health Service Agency Information Collection Activities: Fast Track Generic Clearance for the Collection of Qualitative Feedback on Agency Service Delivery: IHS Web Site...

  9. The influence of preoperative risk stratification on fast-tracking patients after pulmonary resection.

    PubMed

    Bryant, Ayesha S; Cerfolio, Robert J

    2008-02-01

    Fast-tracking protocols or postoperative care computerized algorithms have been shown to reduce hospital length of stay and reduce costs; however, not all patients can be fast-tracked. Certain patient characteristics may put patients at increased risk to fail fast-tracking. Additionally some patients have multiple risk factors that have an additive effect that puts them at an even increased risk to fail fast-tracking, and more importantly, to significant morbidity. It is a mistake to force these protocols on all patients because it can lead to increased complications, readmissions, and low patient and family satisfaction. By carefully analyzing surgical results via accurate prospective databases, the types of patients who fail fast-tracking and the reasons they fail can be identified. Once these characteristics are pinpointed, specific changes to the postoperative algorithm can be implemented, and these alterations can lead to improved outcomes. The authors have shown that by using pain pumps instead of epidurals in elderly patients we can improve outcomes and still fast-track octogenarians with minimal morbidity and high-patient satisfaction. We have also shown that the increased use of physical therapy and respiratory treatments (important parts of the care of all patients after pulmonary resection, but a limited resource in most hospitals) may also lead to improved surgical results for those who have low FEV1% and DLco%. Further studies are needed. Although fast-tracking protocols cannot be applied to all, the vast majority of patients who undergo elective pulmonary resection, even those at high risk, can undergo safe, efficient, and cost-saving care via preset postoperative algorithms. When the typical daily events are convened each morning and the planned date of discharge is frequently communicated with the patient and family before surgery and each day in the hospital, most patients can be safely fast-tracked with high satisfaction and outstanding results.

  10. Ultrafast Faraday Rotation of Slow Light

    NASA Astrophysics Data System (ADS)

    Musorin, A. I.; Sharipova, M. I.; Dolgova, T. V.; Inoue, M.; Fedyanin, A. A.

    2016-08-01

    The active control of optical signals in the time domain is what science and technology demand in fast all-optical information processing. Nanostructured materials can modify the group velocity and slow the light down, as the artificial light dispersion emerges. We observe the ultrafast temporal behavior of the Faraday rotation within a single femtosecond laser pulse under conditions of slow light in a one-dimensional magnetophotonic crystal. The Faraday effect changes by 20% over the time of 150 fs. This might be applicable to the fast control of light in high-capacity photonic devices.

  11. Fast neutron detection with coincidence counting of recoil tracks in CR-39

    NASA Astrophysics Data System (ADS)

    Lengar, I.; Skvarč, J.; Ilić, R.

    2002-06-01

    Unpredictable background is often the major drawback in the assessment of low fluences of fast neutrons with solid state nuclear track detectors. The problem can be effectively solved by counting coincidence tracks in two detector foils that are in close contact during the irradiation. The detection of fast neutrons performed with a pair of CR-39 detector foils, subsequent chemical etching and evaluation of the etched tracks by an automatic track counting system was studied. After counting, only tracks produced by the same recoil nuclei in the surface layers of both detector foils were taken into account. In this way, the background due to objects that cannot be separated from tracks by an automatic counting system was drastically reduced. Emphasis was given to determining the properties of such a coincidence fast neutron detector based on utilisation of CR-39. The response of the coincidence detector was found to be 3×10 -5 tracks/neutron and is comparable with a detector based on counting tracks in a single foil of CR-39. The lower neutron detection limit was found to be 2×10 4 cm -2 with a counting area of 10 cm 2, and is two orders of magnitude lower than that obtained with a detector based on counting tracks in a single foil of CR-39.

  12. The Fleet Application for Scheduling and Tracking (FAST) Management Website

    NASA Technical Reports Server (NTRS)

    Marrero-Perez, Radames J.

    2014-01-01

    The FAST application was designed to replace the paper and pen method of checking out and checking in GSA Vehicles at KSC. By innovating from a paper and pen based checkout system to a fully digital one, not only the resources wasted by printing the checkout forms have been reduced, but it also reduces significantly the time that users and fleet managers need to interact with the system as well as improving the record accuracy for each vehicle. The vehicle information is pulled from a centralized database server in the SPSDL. In an attempt to add a new feature to the FAST application, the author of this report (alongside the FAST developers) has been designing and developing the FAST Management Website. The GSA fleet managers had to rely on the FAST developers in order to add new vehicles, edit vehicles and previous transactions, or for generating vehicles reports. By providing an easy-to-use FAST Management Website portal, the GSA fleet managers are now able to easily move vehicles, edit records, and print reports.

  13. Study of hardware implementations of fast tracking algorithms

    NASA Astrophysics Data System (ADS)

    Song, Z.; De Lentdecker, G.; Dong, J.; Huang, G.; Léonard, A.; Robert, F.; Wang, D.; Yang, Y.

    2017-02-01

    Real-time track reconstruction at high event rates is a major challenge for future experiments in high energy physics. To perform pattern-recognition and track fitting, artificial retina or Hough transformation methods have been introduced in the field which have to be implemented in FPGA firmware. In this note we report on a case study of a possible FPGA hardware implementation approach of the retina algorithm based on a Floating-Point core. Detailed measurements with this algorithm are investigated. Retina performance and capabilities of the FPGA are discussed along with perspectives for further optimization and applications.

  14. The ATLAS Fast Tracker and Tracking at the High-Luminosity LHC

    NASA Astrophysics Data System (ADS)

    Ilic, N.

    2017-02-01

    The increase in centre-of-mass energy and luminosity of the Large Hadron Collider makes controlling trigger rates with high efficiency challenging. The ATLAS Fast TracKer is a hardware processor built to reconstruct tracks at a rate of up to 100 kHz and provide them to the high level trigger. The tracker reconstructs tracks by matching incoming detector hits with pre-defined track patterns stored in associative memory on custom ASICs. Inner detector hits are fitted to these track patterns using modern FPGAs. This proceeding describe the electronics system used for the massive parallelization performed by the Fast TracKer. An overview of the installation, commissioning and running of the system is given. The ATLAS upgrades planned to enable tracking at the High-Luminosity Large Hadron Collider are also discussed.

  15. Broadband Faraday isolator.

    PubMed

    Berent, Michał; Rangelov, Andon A; Vitanov, Nikolay V

    2013-01-01

    Driving on an analogy with the technique of composite pulses in quantum physics, we theoretically propose a broadband Faraday rotator and thus a broadband optical isolator, which is composed of sequences of ordinary Faraday rotators and achromatic quarter-wave plates rotated at the predetermined angles.

  16. Michael Faraday's Bicentenary.

    ERIC Educational Resources Information Center

    Williams, L. Pearce; And Others

    1991-01-01

    Six articles discuss the work of Michael Faraday, a chemist whose work revolutionized physics and led directly to both classical field and relativity theory. The scientist as a young man, the electromagnetic experiments of Faraday, his search for the gravelectric effect, his work on optical glass, his laboratory notebooks, and his creative use of…

  17. The first 6 weeks of recovery after primary total hip arthroplasty with fast track

    PubMed Central

    Klapwijk, Lisette C M; Mathijssen, Nina M C; Van Egmond, Jeroen C; Verbeek, Bianca M; Vehmeijer, Stephan B W

    2017-01-01

    Background and purpose Fast-track protocols have been introduced worldwide to improve the recovery after total hip arthroplasty (THA). These protocols have reduced the length of hospital stay (LOS), and THA in an outpatient setting is also feasible. However, less is known regarding the first weeks after THA with fast track. We examined patients’ experiences of the first 6 weeks after hospital discharge following inpatient and outpatient THA with fast track. Patients and methods In a prospective cohort study, 100 consecutive patients who underwent THA surgery in a fast-track setting between February 2015 and October 2015 received a diary for 6 weeks. This diary contained various internationally validated questionnaires including HOOS-PS, OHS, EQ-5D, SF-12, and ICOAP. In addition, there were general questions regarding pain, the wound, physiotherapy, and thrombosis prophylaxis injections. Results 94 patients completed the diary, 42 of whom were operated in an outpatient setting. Pain and use of pain medication had gradually decreased during the 6 weeks. Function and quality of life gradually improved. After 6 weeks, 91% of all patients reported better functioning and less pain than preoperatively. Interpretation Fast track improves early functional outcome, and the PROMs reported during the first 6 weeks in this study showed continued improvement. They can be used as a baseline for future studies. The PROMs reported could also serve as a guide for staff and patients alike to modify expectations and therefore possibly improve patient satisfaction. PMID:28079428

  18. Fast and long term lipid droplet tracking with CARS microscopy.

    PubMed

    Jüngst, Christian; Winterhalder, Martin J; Zumbusch, Andreas

    2011-06-01

    Photobleaching of organic fluorophores commonly used in fluorescence microscopy puts a limit to the number of images which can be acquired. Label-free imaging techniques therefore offer advantages both for rapid image acquisition and for long-term observations. CARS microscopy is a label-free imaging technique offering molecule specific contrast. Here we demonstrate that CARS microscopy allows video-rate tracking of intracellular transport of lipid droplets, but also continuous long-term observation of cells over several hours.

  19. Note: Fast neutron efficiency in CR-39 nuclear track detectors

    SciTech Connect

    Cavallaro, S.

    2015-03-15

    CR-39 samples are commonly employed for fast neutron detection in fusion reactors and in inertial confinement fusion experiments. The literature reported efficiencies are strongly depending on experimental conditions and, in some cases, highly dispersed. The present note analyses the dependence of efficiency as a function of various parameters and experimental conditions in both the radiator-assisted and the stand-alone CR-39 configurations. Comparisons of literature experimental data with Monte Carlo calculations and optimized efficiency values are shown and discussed.

  20. Restoring integrity-A grounded theory of coping with a fast track surgery programme.

    PubMed

    Jørgensen, Lene Bastrup; Fridlund, Bengt

    2016-01-01

    Aims and objectives The aim of this study was to generate a theory conceptualizing and explaining behavioural processes involved in coping in order to identify the predominant coping types and coping type-specific features. Background Patients undergoing fast track procedures do not experience a higher risk of complications, readmission, or mortality. However, such programmes presuppose an increasing degree of patient involvement, placing high educational, physical, and mental demands on the patients. There is a lack of knowledge about how patients understand and cope with fast track programmes. Design The study design used classical grounded theory. Methods The study used a multimodal approach with qualitative and quantitative data sets from 14 patients. Results Four predominant types of coping, with distinct physiological, cognitive, affective, and psychosocial features, existed among patients going through a fast track total hip replacement programme. These patients' main concern was to restore their physical and psychosocial integrity, which had been compromised by reduced function and mobility in daily life. To restore integrity they economized their mental resources, while striving to fulfil the expectations of the fast track programme. This goal was achieved by being mentally proactive and physically active. Three out of the four predominant types of coping matched the expectations expressed in the fast track programme. The non-matching behaviour was seen among the most nervous patients, who claimed the right to diverge from the programme. Conclusion In theory, four predominant types of coping with distinct physiological, cognitive, affective, and psychosocial features occur among patients going through a fast track total hip arthroplasty programme.

  1. Restoring integrity—A grounded theory of coping with a fast track surgery programme

    PubMed Central

    Jørgensen, Lene Bastrup; Fridlund, Bengt

    2016-01-01

    Aims and objectives The aim of this study was to generate a theory conceptualizing and explaining behavioural processes involved in coping in order to identify the predominant coping types and coping type-specific features. Background Patients undergoing fast track procedures do not experience a higher risk of complications, readmission, or mortality. However, such programmes presuppose an increasing degree of patient involvement, placing high educational, physical, and mental demands on the patients. There is a lack of knowledge about how patients understand and cope with fast track programmes. Design The study design used classical grounded theory. Methods The study used a multimodal approach with qualitative and quantitative data sets from 14 patients. Results Four predominant types of coping, with distinct physiological, cognitive, affective, and psychosocial features, existed among patients going through a fast track total hip replacement programme. These patients’ main concern was to restore their physical and psychosocial integrity, which had been compromised by reduced function and mobility in daily life. To restore integrity they economized their mental resources, while striving to fulfil the expectations of the fast track programme. This goal was achieved by being mentally proactive and physically active. Three out of the four predominant types of coping matched the expectations expressed in the fast track programme. The non-matching behaviour was seen among the most nervous patients, who claimed the right to diverge from the programme. Conclusion In theory, four predominant types of coping with distinct physiological, cognitive, affective, and psychosocial features occur among patients going through a fast track total hip arthroplasty programme. PMID:26751199

  2. Real time Faraday spectrometer

    DOEpatents

    Smith, Jr., Tommy E.; Struve, Kenneth W.; Colella, Nicholas J.

    1991-01-01

    This invention uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements.

  3. A simple backscattering microscope for fast tracking of biological molecules

    NASA Astrophysics Data System (ADS)

    Sowa, Yoshiyuki; Steel, Bradley C.; Berry, Richard M.

    2010-11-01

    Recent developments in techniques for observing single molecules under light microscopes have helped reveal the mechanisms by which molecular machines work. A wide range of markers can be used to detect molecules, from single fluorophores to micron sized markers, depending on the research interest. Here, we present a new and simple objective-type backscattering microscope to track gold nanoparticles with nanometer and microsecond resolution. The total noise of our system in a 55 kHz bandwidth is ˜0.6 nm per axis, sufficient to measure molecular movement. We found our backscattering microscopy to be useful not only for in vitro but also for in vivo experiments because of lower background scattering from cells than in conventional dark-field microscopy. We demonstrate the application of this technique to measuring the motion of a biological rotary molecular motor, the bacterial flagellar motor, in live Escherichia coli cells.

  4. Measuring fast-neutron flux by track-etch technique

    SciTech Connect

    Not Available

    1981-01-01

    The method covers the measurement of neutron flux by the use of fissionable materials. Fission fragments emitted by the fissionable materials during neutron bombardment penetrate a suitable recording medium, such as plastic, glass, or mica, that is in contact with the fissionable material. Appropriate etching techniques render the path of the fragment in the recording medium visible under an optical microscope. Since measurement of the decay of radioisotopes is not involved in this method, irradiation times are limited only by the maximum number of fission fragment tracks that can be clearly distinguished without pile up: approximately 2 x 10/sup 5//cm/sup 2/. The method includes a discussion of apparatus, reagents and materials, procedure, calculations, precision, and accuracy. (JMT)

  5. Tracking Changing Environments: Innovators Are Fast, but Not Flexible Learners

    PubMed Central

    Griffin, Andrea S.; Guez, David; Lermite, Françoise; Patience, Madeleine

    2013-01-01

    Behavioural innovations are increasingly thought to provide a rich source of phenotypic plasticity and evolutionary change. Innovation propensity shows substantial variation across avian taxa and provides an adaptive mechanism by which behaviour is flexibly adjusted to changing environmental conditions. Here, we tested for the first time the prediction that inter-individual variation in innovation propensity is equally a measure of behavioural flexibility. We used Indian mynas, Sturnus tristis, a highly successful worldwide invader. Results revealed that mynas that solved an extractive foraging task more quickly learnt to discriminate between a cue that predicted food, and one that did not more quickly. However, fast innovators were slower to change their behaviour when the significance of the food cues changed. This unexpected finding appears at odds with the well-established view that avian taxa with larger brains relative to their body size, and therefore greater neural processing power, are both faster, and more flexible learners. We speculate that the existence of this relationship across taxa can be reconciled with its absence within species by assuming that fast, innovative learners and non innovative, slow, flexible learners constitute two separate individual strategies, which are both underpinned by enhanced neural processing power. This idea is consistent with the recent proposal that individuals may differ consistently in ‘cognitive style’, differentially trading off speed against accuracy in cognitive tasks. PMID:24391981

  6. The Flexible Faraday Cage

    NASA Astrophysics Data System (ADS)

    Gluck, Paul

    2004-03-01

    The Faraday ice-pail experiment is performed when studying the distribution of charges in conductors: Inside a hollow conductor the net charge is zero, and any excess charge resides on the outside surface.

  7. Fast Flux Test Facility Asbestos Location Tracking Program

    SciTech Connect

    REYNOLDS, J.A.

    1999-04-13

    Procedure Number HNF-PRO-408, revision 0, paragraph 1.0, ''Purpose,'' and paragraph 2.0, ''Requirements for Facility Management of Asbestos,'' relate building inspection and requirements for documentation of existing asbestos-containing building material (ACBM) per each building assessment. This documentation shall be available to all personnel (including contractor personnel) entering the facility at their request. Corrective action was required by 400 Area Integrated Annual Appraisal/Audit for Fiscal Year 1992 (IAA-92-0007) to provide this notification documentation. No formal method had been developed to communicate the location and nature of ACBM to maintenance personnel in the Fast Flux Test Facility (FFTF) 400 Area. The scope of this Data Package Document is to locate and evaluate any ACBM found at FFTF which constitutes a baseline. This includes all buildings within the protected area. These findings are compiled from earlier reports, numerous work packages and engineering evaluations of employee findings.

  8. L1Track: A fast Level 1 track trigger for the ATLAS high luminosity upgrade

    NASA Astrophysics Data System (ADS)

    Cerri, Alessandro

    2016-07-01

    With the planned high-luminosity upgrade of the LHC (HL-LHC), the ATLAS detector will see its collision rate increase by approximately a factor of 5 with respect to the current LHC operation. The earliest hardware-based ATLAS trigger stage ("Level 1") will have to provide a higher rejection factor in a more difficult environment: a new improved Level 1 trigger architecture is under study, which includes the possibility of extracting with low latency and high accuracy tracking information in time for the decision taking process. In this context, the feasibility of potential approaches aimed at providing low-latency high-quality tracking at Level 1 is discussed.

  9. Michael Faraday, media man.

    PubMed

    Fara, Patricia

    2006-03-01

    Michael Faraday was an enthusiastic portrait collector, and he welcomed the invention of photography not only as a possible means of recording observations accurately, but also as a method for advertising science and its practitioners. This article (which is part of the Science in the Industrial Revolution series) shows that like many eminent scientists, Faraday took advantage of the burgeoning Victorian media industry by posing in various roles.

  10. New Medical-School Programs Put Students on a Fast Track to the White Coat

    ERIC Educational Resources Information Center

    Mangan, Katherine

    2009-01-01

    California's lieutenant governor has proposed a fast-track medical school that would shave three years off the training needed to become a physician. It is not the first time such an idea has been offered. The proposal, for a hoped-for medical school at the University of California at Merced, struck some medical educators as both unrealistic and…

  11. The Effects of the Fast Track Preventive Intervention on the Development of Conduct Disorder across Childhood

    ERIC Educational Resources Information Center

    Child Development, 2011

    2011-01-01

    The impact of the Fast Track intervention on externalizing disorders across childhood was examined. Eight hundred-ninety-one early-starting children (69% male; 51% African American) were randomly assigned by matched sets of schools to intervention or control conditions. The 10-year intervention addressed parent behavior-management, child social…

  12. Fast Track Randomized Controlled Trial to Prevent Externalizing Psychiatric Disorders: Findings from Grades 3 to 9

    ERIC Educational Resources Information Center

    Journal of the American Academy of Child & Adolescent Psychiatry, 2007

    2007-01-01

    Objective: This study tests the efficacy of the Fast Track Program in preventing antisocial behavior and psychiatric disorders among groups varying in initial risk. Method: Schools within four sites (Durham, NC; Nashville, TN; Seattle, WA; and rural central Pennsylvania) were selected as high-risk institutions based on neighborhood crime and…

  13. Private health insurance in Sweden: Fast-track lanes and the alleged attempts to stop them.

    PubMed

    Lapidus, John

    2017-04-01

    According to the Health and Medical Services Act (1982:763), those who have the greatest need for healthcare shall be given priority. This is being challenged by the rapid emergence of private health insurance which increases the share of private funding and creates fast-track lanes where some people get faster access to healthcare than others. The Stop Law, implemented by a Social Democratic government in 2006, was generally regarded as a way to put an end to the fast-track lanes in Swedish healthcare. Based on a thorough examination of the law and its legislative history - official reports, propositions, comments on official reports - this article argues that the Stop Law was so full of exceptions and loopholes that it did not threaten the existence of fast-track lanes. The same goes for a similar Social Democratic proposal from 2016, which is also examined in the article. Further, the article analyses centre-right wing positions on fast-track lanes in Swedish healthcare. In summary, it is argued that politicians of all stripes have allowed the development to proceed in spite of unanimous support for the idea that Swedish healthcare shall be provided to all on equal terms.

  14. The Status of Girls' Education in Education for All Fast Track Initiative Partner Countries

    ERIC Educational Resources Information Center

    Clarke, Prema

    2011-01-01

    This viewpoint examines girls' performance in primary education in the countries that joined the Education for All Fast Track Initiative between 2002 and 2008. At the time they joined the initiative, a first group of countries (high performers) had already achieved high and equal enrollment of girls and boys. Significant progress is evident in a…

  15. Fast neutrons detection in CR-39 and DAM-ADC nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Abdalla, A. M.; Ashraf, O.; Rammah, Y. S.; Ashry, A. H.; Eisa, M.; Tsuruta, T.

    2015-03-01

    Fast detection of neutrons in CR-39 and DAM-ADC nuclear track detectors were investigated using new etching conditions. The neutron irradiation is performed using a 5 mCi Am-Be source present at the National Institute of Standards (NIS) of Egypt. Using the new etching condition, irradiated CR-39 samples were etched for 4 h and DAM-ADC samples for 80 min. Suitable analyzing software has been used to analyze experimental data.The dependence of neutrons track density on the neutrons fluence is investigated. When etched under optimum conditions, the relationship between track density and fluence is determined which is found to be linear. Detection efficiency has been represented for both SSNTDs and found to be constant with fluence, which reflects the importance of using CR-39 and DAM-ADC detectors in the field of neutron dosimetry. Linear relationship between track density and effective dose is determined.

  16. Optimal Local Searching for Fast and Robust Textureless 3D Object Tracking in Highly Cluttered Backgrounds.

    PubMed

    Seo, Byung-Kuk; Park, Jong-Il; Hinterstoisser, Stefan; Ilic, Slobodan

    2013-06-13

    Edge-based tracking is a fast and plausible approach for textureless 3D object tracking, but its robustness is still very challenging in highly cluttered backgrounds due to numerous local minima. To overcome this problem, we propose a novel method for fast and robust textureless 3D object tracking in highly cluttered backgrounds. The proposed method is based on optimal local searching of 3D-2D correspondences between a known 3D object model and 2D scene edges in an image with heavy background clutter. In our searching scheme, searching regions are partitioned into three levels (interior, contour, and exterior) with respect to the previous object region, and confident searching directions are determined by evaluating candidates of correspondences on their region levels; thus, the correspondences are searched among likely candidates in only the confident directions instead of searching through all candidates. To ensure the confident searching direction, we also adopt the region appearance, which is efficiently modeled on a newly defined local space (called a searching bundle). Experimental results and performance evaluations demonstrate that our method fully supports fast and robust textureless 3D object tracking even in highly cluttered backgrounds.

  17. Optimal local searching for fast and robust textureless 3D object tracking in highly cluttered backgrounds.

    PubMed

    Seo, Byung-Kuk; Park, Hanhoon; Park, Jong-Il; Hinterstoisser, Stefan; Ilic, Slobodan

    2014-01-01

    Edge-based tracking is a fast and plausible approach for textureless 3D object tracking, but its robustness is still very challenging in highly cluttered backgrounds due to numerous local minima. To overcome this problem, we propose a novel method for fast and robust textureless 3D object tracking in highly cluttered backgrounds. The proposed method is based on optimal local searching of 3D-2D correspondences between a known 3D object model and 2D scene edges in an image with heavy background clutter. In our searching scheme, searching regions are partitioned into three levels (interior, contour, and exterior) with respect to the previous object region, and confident searching directions are determined by evaluating candidates of correspondences on their region levels; thus, the correspondences are searched among likely candidates in only the confident directions instead of searching through all candidates. To ensure the confident searching direction, we also adopt the region appearance, which is efficiently modeled on a newly defined local space (called a searching bundle). Experimental results and performance evaluations demonstrate that our method fully supports fast and robust textureless 3D object tracking even in highly cluttered backgrounds.

  18. Following Michael Faraday's Footprints

    NASA Astrophysics Data System (ADS)

    Galeano, Javier

    2011-01-01

    Last fall I had the good fortune of receiving financial support to shoot a documentary about Michael Faraday. I took the opportunity to learn more about this great experimentalist and to visit the highlights of places in his life. In this paper, I would like to share a list and description of some of the most remarkable places in London suitable for following Michael Faraday's footprints. There are many other places in Europe of special interest for the physics teacher,2,3 and some useful guides to help us visit places as "scientific travelers,"4,5 but this paper focuses on Michael Faraday and London. I have personally visited most of the places described below and found the experience to be really worthwhile.

  19. Preventing Serious Conduct Problems in School-Age Youths: The Fast Track Program

    PubMed Central

    Slough, Nancy M.; McMahon, Robert J.; Bierman, Karen L.; Coie, John D.; Dodge, Kenneth A.; Foster, E. Michael; Greenberg, Mark T.; Lochman, John E.; McMahon, Robert J.; Pinderhughes, Ellen E.

    2009-01-01

    Children with early-starting conduct Problems have a very poor prognosis and exact a high cost to society. The Fast Track project is a multisite, collaborative research project investigating the efficacy of a comprehensive, long-term, multicomponent intervention designed to prevent the development of serious conduct problems in high-risk children. In this article, we (a) provide an overview of the development model that serves as the conceptual foundation for the Fast Track intervention and describe its integration into the intervention model; (b) outline the research design and intervention model, with an emphasis on the elementary school phase of the intervention; and (c) summarize findings to dale concerning intervention outcomes. We then provide a case illustration, and conclude with a discussion of guidelines for practitioners who work with children with conduct problems. PMID:19890487

  20. Developmental Mediation of Genetic Variation in Response to the Fast Track Prevention Program

    PubMed Central

    Albert, Dustin; Belsky, Daniel W.; Crowley, D. Max; Bates, John E.; Pettit, Gregory S.; Lansford, Jennifer E.; Dick, Danielle; Dodge, Kenneth A.

    2015-01-01

    We conducted a developmental analysis of genetic moderation of the effect of the Fast Track intervention on adult externalizing psychopathology. The Fast Track intervention enrolled 891 children at high risk to develop externalizing behavior problems when they were in kindergarten. Half of the enrolled children were randomly assigned to receive 10 years of treatment with a range of services and resources provided to the children and their families and the other half to usual care (controls). We previously showed that the effect of the Fast Track intervention on participants’ risk of externalizing psychopathology at age 25 years was moderated by a variant in the Glucocorticoid Receptor Gene (NR3C1). Children who carried copies of the A-allele of the single-nucleotide polymorphism rs10482672 had the highest risk of externalizing psychopathology if they were in the control arm of the trial and the lowest risk of externalizing psychopathology if they were in the treatment arm. In this study, we test a developmental hypothesis about the origins of this for-better-and-for-worse gene-by-intervention interaction (GxI): That the observed GxI effect on adult psychopathology is mediated by the proximal impact of intervention on childhood externalizing problems and adolescent substance use and delinquency. We analyzed longitudinal data tracking the 270 European-American children in the Fast Track RCT with available genetic information (129 intervention children and 141 control-group peers, 69% male) from kindergarten through age 25 years. Results show that the same pattern of “for-better-and-for-worse” susceptibility to intervention observed at the age-25 follow-up was evident already during childhood. At the elementary school follow-ups and at the middle/high-school follow-ups, rs10482672 predicted better adjustment among children receiving the Fast Track intervention, and worse adjustment among children in the control condition. In turn, these proximal GxI effects

  1. Telemedicine support shortens length of stay after fast-track hip replacement.

    PubMed

    Vesterby, Martin Svoldgaard; Pedersen, Preben Ulrich; Laursen, Malene; Mikkelsen, Søren; Larsen, Jens; Søballe, Kjeld; Jørgensen, Lene Bastrup

    2017-02-01

    Background and purpose - Telemedicine could allow patients to be discharged more quickly after surgery and contribute to improve fast-track procedures without compromising quality, patient safety, functionality, anxiety, or other patient-perceived parameters. We investigated whether using telemedicine support (TMS) would permit hospital discharge after 1 day without loss of self-assessed quality of life, loss of functionality, increased anxiety, increased rates of re-admission, or increased rates of complications after hip replacement. Patients and methods - We performed a randomized controlled trial involving 72 Danish patients in 1 region who were referred for elective fast-track total hip replacement between August 2009 and March 2011 (654 were screened for eligibility). Half of the patients received a telemedicine solution connected to their TV. The patients were followed until 1 year after surgery. Results - Length of stay was reduced from 2.1 days (95% CI: 2.0-2.3) to 1.1 day (CI: 0.9-1.4; p < 0.001) with the TMS intervention. Health-related quality of life increased in both groups, but there were no statistically significant differences between groups. There were also no statistically significant differences between groups regarding timed up-and-go test and Oxford hip score at 3-month follow-up. At 12-month follow-up, the rates of complications and re-admissions were similar between the groups, but the number of postoperative hospital contacts was lower in the TMS group. Interpretation - Length of postoperative stay was shortened in patients with the TMS solution, without compromising patient-perceived or clinical parameters in patients undergoing elective fast-track surgery. These results indicate that telemedicine can be of value in fast-track treatment of patients undergoing total hip replacement.

  2. Transformed Governance and the Education for All-Fast Track Initiative. Policy Brief 2010-02

    ERIC Educational Resources Information Center

    Gartner, David

    2010-01-01

    The Education for All-Fast Track Initiative (FTI) grew out of the "New Focus on Education for All" communique of the G-8 when Canada hosted the summit in 2002 at Kananaskis. As Canada prepares again to host the G-8, and Korea assumes leadership of the newly-empowered G-20, it is a valuable moment to revisit and re-think the current…

  3. Fast left ventricle tracking in CMR images using localized anatomical affine optical flow

    NASA Astrophysics Data System (ADS)

    Queirós, Sandro; Vilaça, João. L.; Morais, Pedro; Fonseca, Jaime C.; D'hooge, Jan; Barbosa, Daniel

    2015-03-01

    In daily cardiology practice, assessment of left ventricular (LV) global function using non-invasive imaging remains central for the diagnosis and follow-up of patients with cardiovascular diseases. Despite the different methodologies currently accessible for LV segmentation in cardiac magnetic resonance (CMR) images, a fast and complete LV delineation is still limitedly available for routine use. In this study, a localized anatomically constrained affine optical flow method is proposed for fast and automatic LV tracking throughout the full cardiac cycle in short-axis CMR images. Starting from an automatically delineated LV in the end-diastolic frame, the endocardial and epicardial boundaries are propagated by estimating the motion between adjacent cardiac phases using optical flow. In order to reduce the computational burden, the motion is only estimated in an anatomical region of interest around the tracked boundaries and subsequently integrated into a local affine motion model. Such localized estimation enables to capture complex motion patterns, while still being spatially consistent. The method was validated on 45 CMR datasets taken from the 2009 MICCAI LV segmentation challenge. The proposed approach proved to be robust and efficient, with an average distance error of 2.1 mm and a correlation with reference ejection fraction of 0.98 (1.9 +/- 4.5%). Moreover, it showed to be fast, taking 5 seconds for the tracking of a full 4D dataset (30 ms per image). Overall, a novel fast, robust and accurate LV tracking methodology was proposed, enabling accurate assessment of relevant global function cardiac indices, such as volumes and ejection fraction

  4. FAST: A fully asynchronous and status-tracking pattern for geoprocessing services orchestration

    NASA Astrophysics Data System (ADS)

    Wu, Huayi; You, Lan; Gui, Zhipeng; Gao, Shuang; Li, Zhenqiang; Yu, Jingmin

    2014-09-01

    Geoprocessing service orchestration (GSO) provides a unified and flexible way to implement cross-application, long-lived, and multi-step geoprocessing service workflows by coordinating geoprocessing services collaboratively. Usually, geoprocessing services and geoprocessing service workflows are data and/or computing intensive. The intensity feature may make the execution process of a workflow time-consuming. Since it initials an execution request without blocking other interactions on the client side, an asynchronous mechanism is especially appropriate for GSO workflows. Many critical problems remain to be solved in existing asynchronous patterns for GSO including difficulties in improving performance, status tracking, and clarifying the workflow structure. These problems are a challenge when orchestrating performance efficiency, making statuses instantly available, and constructing clearly structured GSO workflows. A Fully Asynchronous and Status-Tracking (FAST) pattern that adopts asynchronous interactions throughout the whole communication tier of a workflow is proposed for GSO. The proposed FAST pattern includes a mechanism that actively pushes the latest status to clients instantly and economically. An independent proxy was designed to isolate the status tracking logic from the geoprocessing business logic, which assists the formation of a clear GSO workflow structure. A workflow was implemented in the FAST pattern to simulate the flooding process in the Poyang Lake region. Experimental results show that the proposed FAST pattern can efficiently tackle data/computing intensive geoprocessing tasks. The performance of all collaborative partners was improved due to the asynchronous mechanism throughout communication tier. A status-tracking mechanism helps users retrieve the latest running status of a GSO workflow in an efficient and instant way. The clear structure of the GSO workflow lowers the barriers for geospatial domain experts and model designers to

  5. Telemedicine support shortens length of stay after fast-track hip replacement

    PubMed Central

    Vesterby, Martin Svoldgaard; Pedersen, Preben Ulrich; Laursen, Malene; Mikkelsen, Søren; Larsen, Jens; Søballe, Kjeld; Jørgensen, Lene Bastrup

    2017-01-01

    Background and purpose — Telemedicine could allow patients to be discharged more quickly after surgery and contribute to improve fast-track procedures without compromising quality, patient safety, functionality, anxiety, or other patient-perceived parameters. We investigated whether using telemedicine support (TMS) would permit hospital discharge after 1 day without loss of self-assessed quality of life, loss of functionality, increased anxiety, increased rates of re-admission, or increased rates of complications after hip replacement. Patients and methods — We performed a randomized controlled trial involving 72 Danish patients in 1 region who were referred for elective fast-track total hip replacement between August 2009 and March 2011 (654 were screened for eligibility). Half of the patients received a telemedicine solution connected to their TV. The patients were followed until 1 year after surgery. Results — Length of stay was reduced from 2.1 days (95% CI: 2.0–2.3) to 1.1 day (CI: 0.9–1.4; p < 0.001) with the TMS intervention. Health-related quality of life increased in both groups, but there were no statistically significant differences between groups. There were also no statistically significant differences between groups regarding timed up-and-go test and Oxford hip score at 3-month follow-up. At 12-month follow-up, the rates of complications and re-admissions were similar between the groups, but the number of postoperative hospital contacts was lower in the TMS group. Interpretation — Length of postoperative stay was shortened in patients with the TMS solution, without compromising patient-perceived or clinical parameters in patients undergoing elective fast-track surgery. These results indicate that telemedicine can be of value in fast-track treatment of patients undergoing total hip replacement. PMID:28097941

  6. Following Michael Faraday's Footprints

    ERIC Educational Resources Information Center

    Galeano, Javier

    2011-01-01

    Last fall I had the good fortune of receiving financial support to shoot a documentary about Michael Faraday. I took the opportunity to learn more about this great experimentalist and to visit the highlights of places in his life. In this paper, I would like to share a list and description of some of the most remarkable places in London suitable…

  7. SMAP Faraday Rotation

    NASA Technical Reports Server (NTRS)

    Le Vine, David

    2016-01-01

    Faraday rotation is a change in the polarization as signal propagates through the ionosphere. At L-band it is necessary to correct for this change and measurements are made on the spacecraft of the rotation angle. These figures show that there is good agreement between the SMAP measurements (blue) and predictions based on models (red).

  8. International collaborative project to compare and track the nutritional composition of fast foods

    PubMed Central

    2012-01-01

    Background Chronic diseases are the leading cause of premature death and disability in the world with over-nutrition a primary cause of diet-related ill health. Excess quantities of energy, saturated fat, sugar and salt derived from fast foods contribute importantly to this disease burden. Our objective is to collate and compare nutrient composition data for fast foods as a means of supporting improvements in product formulation. Methods/design Surveys of fast foods will be done in each participating country each year. Information on the nutrient composition for each product will be sought either through direct chemical analysis, from fast food companies, in-store materials or from company websites. Foods will be categorized into major groups for the primary analyses which will compare mean levels of saturated fat, sugar, sodium, energy and serving size at baseline and over time. Countries currently involved include Australia, New Zealand, France, UK, USA, India, Spain, China and Canada, with more anticipated to follow. Discussion This collaborative approach to the collation and sharing of data will enable low-cost tracking of fast food composition around the world. This project represents a significant step forward in the objective and transparent monitoring of industry and government commitments to improve the quality of fast foods. PMID:22838731

  9. A video demonstration of the Li's anastomosis-the key part of the "non-tube no fasting" fast track program for resectable esophageal carcinoma.

    PubMed

    Zheng, Yan; Li, Yin; Wang, Zongfei; Sun, Haibo; Zhang, Ruixiang

    2015-07-01

    The main obstacle of fast track surgery for esophagectomy is early oral feeding. The main concern of early oral feeding is the possibility of increasing the incidence of anastomotic leakage. Dr. Yin Li used the Li's anastomosis to ensure oral feeding at will the first day after esophagectomy. This safe and efficient anastomosis method significantly reduced the anastomotic leak rate, the number of post-operative days and stricture. Importantly, the "non-tube no fasting" fast track program for esophageal cancer patients was conducted smoothly with Li's anastomosis. This article was focused on the surgical procedure of Li's anastomosis.

  10. First results of the silicon telescope using an 'artificial retina' for fast track finding

    SciTech Connect

    Neri, N.; Abba, A.; Caponio, F.; Geraci, A.; Grizzuti, M.; Lusardi, N.; Citterio, M.; Coelli, S.; Fu, J.; Monti, M.; Petruzzo, M.; Bedeschi, F.; Ninci, D.; Piucci, A.; Spinella, F.; Walsh, J.; Cenci, R.; Marino, P.; Morello, M. J.; Stracka, S.; Punzi, G.; Tonelli, D.; Ristori, L.

    2015-07-01

    We present the first results of the prototype of a silicon tracker with trigger capabilities based on a novel approach for fast track finding. The working principle of the 'artificial retina' is inspired by the processing of visual images by the brain and it is based on extensive parallelization of data distribution and pattern recognition. The algorithm has been implemented in commercial FPGAs in three main logic modules: a switch for the routing of the detector hits, a pool of engines for the digital processing of the hits, and a block for the calculation of the track parameters. The architecture is fully pipelined and allows the reconstruction of real-time tracks with a latency less then 100 clock cycles, corresponding to 0.25 microsecond at 400 MHz clock. The silicon telescope consists of 8 layers of single-sided silicon strip detectors with 512 strips each. The detector size is about 10 cm x 10 cm and the strip pitch is 183 μm. The detectors are read out by the Beetle chip, a custom ASICs developed for LHCb, which provides the measurement of the hit position and pulse height of 128 channels. The 'artificial retina' algorithm has been implemented on custom data acquisition boards based on FPGAs Xilinx Kintex 7 lx160. The parameters of the tracks detected are finally transferred to host PC via USB 3.0. The boards manage the read-out ASICs and the sampling of the analog channels. The read-out is performed at 40 MHz on 4 channels for each ASIC that corresponds to a decoding of the telescope information at 1.1 MHz. We report on the first results of the fast tracking device and compare with simulations. (authors)

  11. Effects of a fast-track area on emergency department performance.

    PubMed

    Sanchez, Miquel; Smally, Alan J; Grant, Robert J; Jacobs, Lenworth M

    2006-07-01

    To determine if a fast-track area (FTA) would improve Emergency Department (ED) performance, a historical cohort study was performed in the ED of a tertiary care adult hospital in the United States. Two 1-year consecutive periods, pre fast track area (FTA) opening-from February 1, 2001 to January 31, 2002 and after FTA opening-from February 1, 2002 to January 31, 2003 were studied. Daily values of the following variables were obtained from the ED patient tracking system: 1) To assess ED effectiveness: waiting time to be seen (WT), length of stay (LOS); 2) To assess ED care quality: rate of patients left without being seen (LWBS), mortality, and revisits; 3) To assess determinants of patient homogeneity between periods: daily census, age, acuity index, admission rate and emergent patient rate. For comparisons, the Wilcoxon test and the Student's t-test were used to analyze the data. Results showed that despite an increase in the daily census (difference [diff] 8.71, 95% confidence interval [CI] 6 to 11.41), FTA was associated with a decrease in WT (diff -51 min, 95% CI [-56 to -46]), LOS (diff -28 min, 95% CI [-31 to -23]) and LWBS (diff -4.06, 95% CI [-4.48 to -3.46]), without change in the rates of mortality or revisits. In conclusion, the opening of a FTA improved ED effectiveness, measured by decreased WT and LOS, without deterioration in the quality of care provided, measured by rates of mortality and revisits.

  12. Fast template matching based on grey prediction for real-time object tracking

    NASA Astrophysics Data System (ADS)

    Lv, Mingming; Hou, Yuanlong; Liu, Rongzhong; Hou, Runmin

    2017-02-01

    Template matching is a basic algorithm for image processing, and real-time is a crucial requirement of object tracking. For real-time tracking, a fast template matching algorithm based on grey prediction is presented, where computation cost can be reduced dramatically by minimizing search range. First, location of the tracked object in the current image is estimated by Grey Model (GM). GM(1,1), which is the basic model of grey prediction, can use some known information to foretell the location. Second, the precise position of the object in the frame is computed by template matching. Herein, Sequential Similarity Detection Algorithm (SSDA) with a self-adaptive threshold is employed to obtain the matching position in the neighborhood of the predicted location. The role of threshold in SSDA is important, as a proper threshold can make template matching fast and accurate. Moreover, a practical weighted strategy is utilized to handle scale and rotation changes of the object, as well as illumination changes. The experimental results show the superior performance of the proposed algorithm over the conventional full-search method, especially in terms of executive time.

  13. Fast track in colo-rectal surgery. Preliminary experience in a rural hospital

    PubMed Central

    FRONTERA, D.; ARENA, L.; CORSALE, I.; FRANCIOLI, N.; MAMMOLITI, F.; BUCCIANELLI, E.

    2014-01-01

    Background “Fast Track surgery” is a therapeutic program of large application, despite some doubts about its applicability and real validity. Literature review shows that this approach to colo-rectal surgery, particularly video-assisted, can allow a rapid recovery, better performance and a faster postoperative functional autonomy of the work, which can be discharged without cause additional welfare costs; in addition it can be reproducible in different health reality. Purpose To analyze the possibility to apply the Fast Truck protocol in patients undergoing colorectal surgery in a rural hospital and non specialistic Unit of Surgery. Patients and methods We have conducted a prospective, randomized study on 80 patients subjected to colorectal surgery in the last year. Results The protocol was observed in 95% of cases, compliance with the Fast Track was high and general morbidity was limited (7.8%). Conclusion This “aggressive” approach, which has fundamentally altered the usual surgical behavior, seems to allow a mean length of stay significantly lower than in controls (p < 0.05) with positive implications for patients and containment of health care costs, even after discharge (no need for home care in 92% of cases, no early re-admittance to the hospital). Homogeneous protocols are desirable, as well as an increased enrollment, to consolidate these rehabilitation programs in order to provide a reference for all hospitals. PMID:25644732

  14. Modified Faraday cup

    DOEpatents

    Elmer, J.W.; Teruya, A.T.; O`Brien, D.W.

    1996-09-10

    A tomographic technique for measuring the current density distribution in electron beams using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams is disclosed. The modified Faraday cup includes a narrow slit and is rotated by a stepper motor and can be moved in the x, y and z directions. The beam is swept across the slit perpendicular thereto and controlled by deflection coils, and the slit rotated such that waveforms are taken every few degrees from 0{degree} to 360{degree} and the waveforms are recorded by a digitizing storage oscilloscope. Two-dimensional and three-dimensional images of the current density distribution in the beam can be reconstructed by computer tomography from this information, providing quantitative information about the beam focus and alignment. 12 figs.

  15. Modified Faraday cup

    DOEpatents

    Elmer, John W.; Teruya, Alan T.; O'Brien, Dennis W.

    1996-01-01

    A tomographic technique for measuring the current density distribution in electron beams using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. The modified Faraday cup includes a narrow slit and is rotated by a stepper motor and can be moved in the x, y and z directions. The beam is swept across the slit perpendicular thereto and controlled by deflection coils, and the slit rotated such that waveforms are taken every few degrees form 0.degree. to 360.degree. and the waveforms are recorded by a digitizing storage oscilloscope. Two-din-tensional and three-dimensional images of the current density distribution in the beam can be reconstructed by computer tomography from this information, providing quantitative information about the beam focus and alignment.

  16. Infrared image guidance for ground vehicle based on fast wavelet image focusing and tracking

    NASA Astrophysics Data System (ADS)

    Akiyama, Akira; Kobayashi, Nobuaki; Mutoh, Eiichiro; Kumagai, Hideo; Yamada, Hirofumi; Ishii, Hiromitsu

    2009-08-01

    We studied the infrared image guidance for ground vehicle based on the fast wavelet image focusing and tracking. Here we uses the image of the uncooled infrared imager mounted on the two axis gimbal system and the developed new auto focusing algorithm on the Daubechies wavelet transform. The developed new focusing algorithm on the Daubechies wavelet transform processes the result of the high pass filter effect to meet the direct detection of the objects. This new focusing gives us the distance information of the outside world smoothly, and the information of the gimbal system gives us the direction of objects in the outside world to match the sense of the spherical coordinate system. We installed this system on the hand made electric ground vehicle platform powered by 24VDC battery. The electric vehicle equips the rotary encoder units and the inertia rate sensor units to make the correct navigation process. The image tracking also uses the developed newt wavelet focusing within several image processing. The size of the hand made electric ground vehicle platform is about 1m long, 0.75m wide, 1m high, and 50kg weight. We tested the infrared image guidance for ground vehicle based on the new wavelet image focusing and tracking using the electric vehicle indoor and outdoor. The test shows the good results by the developed infrared image guidance for ground vehicle based on the new wavelet image focusing and tracking.

  17. Atom ejection from a fast-ion track: A molecular-dynamics study

    SciTech Connect

    Urbassek, H.M. ); Kafemann, H. ); Johnson, R.E. )

    1994-01-01

    As a model for atom ejection from fast-ion tracks, molecular-dynamics simulations of a cylindrical track of energized particles are performed. An idealized situation is studied where every atom in a cylindrical track of radius [ital R][sub 0] is energized with energy [ital E][sub 0]. The emission yield [ital Y]([ital E][sub 0],[ital R][sub 0]) shows the existence of two ejection regimes. If the particle energy [ital E][sub 0] is below the sublimation energy [ital U] of the material, a threshold regime is seen in which [ital Y] rises roughly like the third power of [ital E][sub 0]; for high-energy densities [ital E][sub 0][approx gt][ital U], the yield rises much more slowly, roughly linearly. In both cases, ejected particles mostly originate from the track, rather than from its surroundings, and from the first or the first few monolayers. The behavior found is interpreted here in terms of emission due to a pressure-driven jet (linear regime) or due to a pressure pulse (threshold regime). These both behave differently from the often-used thermal-spike sputtering model.

  18. Fast detection of alpha particles in DAM-ADC nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Rammah, Y. S.; Ashraf, O.; Abdalla, A. M.; Eisa, M.; Ashry, A. H.; Tsuruta, T.

    2015-02-01

    Fast detection of alpha particles in DAM-ADC nuclear track detectors using a new chemical etchant was investigated. 252Cf and 241Am sources were used for irradiating samples of DAM-ADC SSNTDs with fission fragments and alpha particles in air at normal temperature and pressure. A series of experimental chemical etching are carried out using new etching solution (8 ml of 10 N NaOH+ 1 ml CH3OH) at 60 °C to detect alpha particle in short time in DAM-ADC detectors. Suitable analyzing software has been used to analyze experimental data. From fission and alpha track diameters, the value of bulk etching rate is equal to 8.52 μm/h. Both of the sensitivity and etching efficiency were found to vary with the amount of methanol in the etching solution and etching time. The DAM-ADC detectors represent the best efficiency applicable in detectors in the entire range of alpha energies (from 1 to 5 MeV). The activation energies of this etchant have been calculated; track activation energy, ET, has been found to be lower than the bulk activation energy, EB, for the DAM-ADC nuclear track detectors. These results are in more agreement with the previous work.

  19. Fast tracking of a given heart rate profile in treadmill exercise.

    PubMed

    Weng, Kaili; Turk, Basil; Dolores, Louis; Nguyen, Tuan N; Celler, Branko; Su, Steven; Nguyen, Hung T

    2010-01-01

    This paper investigates the application of a multi-loop PID controller in an automated treadmill exercise machine. The approach is to design a computer-controlled treadmill control system for the regulation of heart rate (HR) during treadmill exercise. A single-input and multiple-output (SIMO) controller was implemented to fast track a given heart rate profile in treadmill exercise. Two separate single-input and single-output (SISO) PID control systems are initially implemented to modify either the treadmill speed or its angle of inclination in order to achieve a desired HR. The purpose of this paper is to apply a SIMO control system by implementing a control algorithm which includes the two PID controllers working simultaneously to track the desired HR profile. The performance of the SIMO and SISO control systems are compared through the closed loop responses recorded during experimentation. This would also help future development of safe treadmill exercise system.

  20. Michael Faraday vs. the Spiritualists

    NASA Astrophysics Data System (ADS)

    Hirshfeld, Alan

    2006-12-01

    In the 1850s, renowned physicist Michael Faraday launched a public campaign against pseudoscience and spiritualism, which were rampant in England at the time. Faraday objected especially to claims that electrical or magnetic forces were responsible for paranormal phenomena, such as table-spinning and communication with the dead. Using scientific methods, Faraday unmasked the deceptions of spiritualists, clairvoyants and mediums and also laid bare the credulity of a public ill-educated in science. Despite his efforts, Victorian society's fascination with the paranormal swelled. Faraday's debacle anticipates current controversies about public science education and the interface between science and religion. This episode is one of many described in the new biography, The Electric Life of Michael Faraday (Walker & Co.), which chronicles Faraday's discoveries and his unlikely rise from poverty to the pinnacle of the English science establishment.

  1. Does BMI influence hospital stay and morbidity after fast-track hip and knee arthroplasty?

    PubMed

    Husted, Henrik; Jørgensen, Christoffer C; Gromov, Kirill; Kehlet, Henrik

    2016-10-01

    Background and purpose - Body mass index (BMI) outside the normal range possibly affects the perioperative morbidity and mortality following total hip arthroplasty (THA) and total knee arthroplasty (TKA) in traditional care programs. We determined perioperative morbidity and mortality in such patients who were operated with the fast-track methodology and compared the levels with those in patients with normal BMI. Patients and methods - This was a prospective observational study involving 13,730 procedures (7,194 THA and 6,536 TKA operations) performed in a standardized fast-track setting. Complete 90-day follow-up was achieved using national registries and review of medical records. Patients were grouped according to BMI as being underweight, of normal weight, overweight, obese, very obese, and morbidly obese. Results - Median length of stay (LOS) was 2 (IQR: 2-3) days in all BMI groups. 30-day re-admission rates were around 6% for both THA (6.1%) and TKA (5.9%), without any statistically significant differences between BMI groups in univariate analysis (p > 0.4), but there was a trend of a protective effect of overweight for both THA (p = 0.1) and TKA (p = 0.06). 90-day re-admission rates increased to 8.6% for THA and 8.3% for TKA, which was similar among BMI groups, but there was a trend of lower rates in overweight and obese TKA patients (p = 0.08 and p = 0.06, respectively). When we adjusted for preoperative comorbidity, high BMI in THA patients (very obese and morbidly obese patients only) was associated with a LOS of >4 days (p = 0.001), but not with re-admission. No such relationship existed for TKA. Interpretation - A fast-track setting resulted in similar length of hospital stay and re-admission rates regardless of BMI, except for very obese and morbidly obese THA patients.

  2. Biology's built-in Faraday cages

    NASA Astrophysics Data System (ADS)

    Klee, Maurice M.

    2014-05-01

    Biological fluids are water-based, ionic conductors. As such, they have both high relative dielectric constants and substantial conductivities, meaning they are lossy dielectrics. These fluids contain charged molecules (free charges), whose movements play roles in essentially all cellular processes from metabolism to communication with other cells. Using the problem of a point source in air above a biological fluid of semi-infinite extent, the bound charges in the fluid are shown to perform the function of a fast-acting Faraday cage, which protects the interior of the fluid from external electric fields. Free charges replace bound charges in accordance with the fluid's relaxation time, thereby providing a smooth transition between the initial protection provided by the bound charges and the steady state protection provided by the free charges. The electric fields within the biological fluid are thus small for all times just as they would be inside a classical Faraday cage.

  3. "Fast-Tracking": Ain't No Golden Parachute So Don't Slide off the Rainbow.

    ERIC Educational Resources Information Center

    Newburger, Craig; Butler, Jerry

    Awareness of the corporate cultural phenomenon of fast-tracking, a process whereby executives are advanced within and among organizations, should assist communication students and practicing professionals to become more effective corporate communicators. A critical distinction between self-directed fast-trackers and their corporately-sanctioned…

  4. Fast Track to the Cloud: Design Patterns for 12-Factor Earth Sciences Applications

    NASA Technical Reports Server (NTRS)

    Pawloski, Andrew; McLaughlin, Brett; Lynnes, Christopher

    2016-01-01

    As expanding service offerings and decreasing prices make the cloud increasingly attractive to Earth Science applications, there are nontrivial practical considerations which can hinder its meaningful use. In this talk, we will discuss architectural recommendations and lessons learned while working on EOSDIS' cloud efforts, particularly the NASA-compliant General Application Platform (NGAP) and its associated applications. Prominent in our findings is the importance of 12-factor design patterns and the powerful "wins" they enable in the cloud. We will share our strategies for "fast-tracking" applications to the cloud --whether they be legacy, planned for the future, or somewhere in between.

  5. How Does the Fast Track Intervention Prevent Adverse Outcomes in Young Adulthood?

    PubMed Central

    Sorensen, Lucy C.; Dodge, Kenneth A.

    2015-01-01

    Numerous studies have shown that childhood interventions can foster improved outcomes in adulthood. Less well understood is precisely how – that is, through which developmental pathways – these interventions work. This study assesses mechanisms by which the Fast Track project (n=891), a randomized intervention in the early 1990s for high-risk children in four communities (Durham, NC; Nashville, TN; rural PA; and Seattle, WA), reduced delinquency, arrests, and health and mental health service utilization in adolescence through young adulthood (ages 12–20). A decomposition of treatment effects indicates that about a third of Fast Track’s impact on later crime outcomes can be accounted for by improvements in social and self-regulation skills during childhood (ages 6–11), such as prosocial behavior, emotion regulation and problem solving. These skills proved less valuable for the prevention of mental and physical health problems. PMID:26670938

  6. A fast algorithm for muon track reconstruction and its application to the ANTARES neutrino telescope

    NASA Astrophysics Data System (ADS)

    Aguilar, J. A.; Al Samarai, I.; Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Assis Jesus, A. C.; Astraatmadja, T.; Aubert, J.-J.; Auer, R.; Baret, B.; Basa, S.; Bazzotti, M.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bogazzi, C.; Bou-Cabo, M.; Bouwhuis, M. C.; Brown, A. M.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Cârloganu, C.; Carminati, G.; Carr, J.; Cecchini, S.; Charvis, Ph.; Chiarusi, T.; Circella, M.; Coniglione, R.; Costantini, H.; Cottini, N.; Coyle, P.; Curtil, C.; Decowski, M. P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti, Q.; Drouhin, D.; Eberl, T.; Emanuele, U.; Ernenwein, J.-P.; Escoffier, S.; Fehr, F.; Flaminio, V.; Fritsch, U.; Fuda, J.-L.; Galatà, S.; Gay, P.; Giacomelli, G.; Gómez-González, J. P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Herold, B.; Hößl, J.; Hsu, C. C.; de Jong, M.; Kadler, M.; Kalantar-Nayestanaki, N.; Kalekin, O.; Kappes, A.; Katz, U.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Larosa, G.; Lefèvre, D.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Lucarelli, F.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Mazure, A.; Meli, A.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Naumann, C.; Neff, M.; Palioselitis, D.; Păvălaş, G. E.; Payre, P.; Petrovic, J.; Picot-Clemente, N.; Picq, C.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Reed, C.; Riccobene, G.; Richardt, C.; Richter, R.; Rostovtsev, A.; Rujoiu, M.; Russo, G. V.; Salesa, F.; Sapienza, P.; Schöck, F.; Schuller, J.-P.; Shanidze, R.; Simeone, F.; Spiess, A.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Taiuti, M.; Tamburini, C.; Tasca, L.; Toscano, S.; Vallage, B.; Van Elewyck, V.; Vannoni, G.; Vecchi, M.; Vernin, P.; Wijnker, G.; de Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J. D.; Zúñiga, J.

    2011-04-01

    An algorithm is presented, that provides a fast and robust reconstruction of neutrino induced upward-going muons and a discrimination of these events from downward-going atmospheric muon background in data collected by the ANTARES neutrino telescope. The algorithm consists of a hit merging and hit selection procedure followed by fitting steps for a track hypothesis and a point-like light source. It is particularly well-suited for real time applications such as online monitoring and fast triggering of optical follow-up observations for multi-messenger studies. The performance of the algorithm is evaluated with Monte Carlo simulations and various distributions are compared with that obtained in ANTARES data.

  7. "Fast track surgery" in the north-west of Italy: influence on the orientation of surgical practice.

    PubMed

    Pozzi, G; Falcone, A; Sabbatino, F; Solej, M; Nano, M

    2012-06-01

    Fast track surgery is a peri-operative management model, including different strategies to improve patients' convalescence, avoid metabolic alterations, reduce complications, and shorten hospital stay. Prerequisite is coordination between different practitioners (surgeon, anaesthetist, nurse, nutritionist, physiotherapist). The purpose of our investigation is to understand the level of fast track surgery application in Piedmont and to evidence analogies and differences among departments. We projected an investigation proposing, to every surgery department in Piedmont, a multiple-choice questionnaire evaluating the level of fast track surgery peri-operative interventions' application. Data analysis was conducted in two points of view: the transversal one with an overview of answer's percentages, the longitudinal one correlating data through Pearson's index (r). We collected answers by 78 % of balloted departments (38 on 49). Transversal analysis, including the evaluation of percentages of each question, shows that intra-operative period is the most influenced by fast track principles, and that only 12 departments of 38 apply complete protocols. Longitudinal analysis, estimating the whole of each department's answers, demonstrates the absence of statistical significance in the correlation between fast track surgery application and territorial (r = 0.18), economic (r = 0.31), or age (r = 0.06) variables. Influence of fast track surgery is significantly present in our territory, even though it is not fully concretized in protocols. The choice of fast track depends on the instruction, the environment and the sensibility of each surgeon. Knowledge of geographic distribution of departments applying this model can be useful to organize common protocols, starting from more experienced hospitals.

  8. Real-Time Robust Tracking for Motion Blur and Fast Motion via Correlation Filters

    PubMed Central

    Xu, Lingyun; Luo, Haibo; Hui, Bin; Chang, Zheng

    2016-01-01

    Visual tracking has extensive applications in intelligent monitoring and guidance systems. Among state-of-the-art tracking algorithms, Correlation Filter methods perform favorably in robustness, accuracy and speed. However, it also has shortcomings when dealing with pervasive target scale variation, motion blur and fast motion. In this paper we proposed a new real-time robust scheme based on Kernelized Correlation Filter (KCF) to significantly improve performance on motion blur and fast motion. By fusing KCF and STC trackers, our algorithm also solve the estimation of scale variation in many scenarios. We theoretically analyze the problem for CFs towards motions and utilize the point sharpness function of the target patch to evaluate the motion state of target. Then we set up an efficient scheme to handle the motion and scale variation without much time consuming. Our algorithm preserves the properties of KCF besides the ability to handle special scenarios. In the end extensive experimental results on benchmark of VOT datasets show our algorithm performs advantageously competed with the top-rank trackers. PMID:27618046

  9. A new fast scanning system for the measurement of large angle tracks in nuclear emulsions

    NASA Astrophysics Data System (ADS)

    Alexandrov, A.; Buonaura, A.; Consiglio, L.; D'Ambrosio, N.; De Lellis, G.; Di Crescenzo, A.; Di Marco, N.; Galati, G.; Lauria, A.; Montesi, M. C.; Pupilli, F.; Shchedrina, T.; Tioukov, V.; Vladymyrov, M.

    2015-11-01

    Nuclear emulsions have been widely used in particle physics to identify new particles through the observation of their decays thanks to their unique spatial resolution. Nevertheless, before the advent of automatic scanning systems, the emulsion analysis was very demanding in terms of well trained manpower. Due to this reason, they were gradually replaced by electronic detectors, until the '90s, when automatic microscopes started to be developed in Japan and in Europe. Automatic scanning was essential to conceive large scale emulsion-based neutrino experiments like CHORUS, DONUT and OPERA. Standard scanning systems have been initially designed to recognize tracks within a limited angular acceptance (θ lesssim 30°) where θ is the track angle with respect to a line perpendicular to the emulsion plane. In this paper we describe the implementation of a novel fast automatic scanning system aimed at extending the track recognition to the full angular range and improving the present scanning speed. Indeed, nuclear emulsions do not have any intrinsic limit to detect particle direction. Such improvement opens new perspectives to use nuclear emulsions in several fields in addition to large scale neutrino experiments, like muon radiography, medical applications and dark matter directional detection.

  10. Error-Based Observer of a Charge Couple Device Tracking Loop for Fast Steering Mirror

    PubMed Central

    Tang, Tao; Deng, Chao; Yang, Tao; Zhong, Daijun; Ren, Ge; Huang, Yongmei; Fu, Chengyu

    2017-01-01

    The charge couple device (CCD) tracking loop of a fast steering mirror (FSM) is usually used to stabilize line of sight (LOS). High closed-loop bandwidth facilitates good performance. However, low-rate sample and time delay of the CCD greatly limit the high control bandwidth. This paper proposes an error-based observer (EBO) to improve the low-frequency performance of the CCD tracking system. The basic idea is by combining LOS error from the CCD and the controller output to produce the high-gain observer, forwarding into the originally closed-loop control system. This proposed EBO can improve the system both in target tracking and disturbance suppression due to LOS error from the CCD’s sensing of the two signals. From a practical engineering view, the closed-loop stability and robustness of the EBO system are investigated on the condition of gain margin and phase margin of the open-loop transfer function. Two simulations of CCD experiments are provided to verify the benefits of the proposed algorithm. PMID:28264504

  11. Fast-Track Surgery in Gynaecology and Gynaecologic Oncology: A Review of a Rolling Clinical Audit

    PubMed Central

    Carter, Jonathan

    2012-01-01

    Clinical audit is the process by which clinicians are able to demonstrate to themselves, their patients, hospital administrators, and healthcare financial providers the outcome and safety of their clinical practice. It is a process by which the public can be assured of safety and outcomes. A fast-track surgery program was initiated in January 2008, and this paper represents a rolling clinical audit of the outcomes of that program until the end of June 2012. Three hundred and eighty-nine patients underwent fast track surgical management after having a laparotomy for suspected or confirmed gynaecological cancer. There were no exclusions and the data presented represents the practice and outcomes of all patients referred to a single gynaecological oncologist. The majority of patients were deemed to have complex surgical procedures performed usually through a vertical midline incision. One third of patients had a nonzero performance status, median weight was 68 kilograms, and median BMI was 26.5 with 31% being classified as obese. Median operating time was 2.25 hours, and the median estimated blood loss was 175 mL. Overall the median length of stay (LOS) was 3 days with 95% of patients tolerating early oral feeding. Four percent of patients required readmission, and 0.5% were required to return to the operating room. Whilst the wound infection rate was 2.6%, there were no ureteric, bowel or neurovascular injuries. Overall there were 2 bladder injuries (0.5%), and the incidence of venous thromboembolism was 1%. Subset analysis was also undertaken. Whilst a number of variables were associated with reduced LOS, on multivariate analysis, benign pathology, shorter operating time, and the ability to tolerate early oral feeding were found to be significant. The data and experience presented is the largest and most extensive reported in the literature relating to fast-track surgery in gynaecology and gynaecologic oncology. The public can be reassured of the safety and

  12. Prediction of engine performance and wall erosion due to film cooling for the 'fast track' ablative thrust chamber

    NASA Technical Reports Server (NTRS)

    Trinh, Huu P.

    1994-01-01

    Efforts have been made at the Propulsion Laboratory (MSFC) to design and develop new liquid rocket engines for small-class launch vehicles. Emphasis of the efforts is to reduce the engine development time with the use of conventional designs while meeting engine reliability criteria. Consequently, the engine cost should be reduced. A demonstrative ablative thrust chamber, called 'fast-track', has been built. To support the design of the 'fast-track' thrust chamber, predictions of the wall temperature and ablation erosion rate of the 'fast-track' thrust chamber have been performed using the computational fluid dynamics program REFLEQS (Reactive Flow Equation Solver). The analysis is intended to assess the amount of fuel to be used for film cooling so that the erosion rate of the chamber ablation does not exceed its allowable limit. In addition, the thrust chamber performance loss due to an increase of the film cooling is examined.

  13. On fading probability density functions of fast-tracked and untracked free-space optical communication channels

    NASA Astrophysics Data System (ADS)

    Zhao, Zhijun; Liao, Rui

    2011-03-01

    Free-space optical (FSO) communication systems suffer from average power loss and instantaneous power fading due to the atmospheric turbulence. The channel fading probability density function (pdf) is of critical importance for FSO communication system design and evaluation. The performance and reliability of FSO communication systems can be greatly enhanced if fast-tacking devices are employed at the transmitter in order to compensate laser beam wander at the receiver aperture. The fast-tracking method is especially effective when communication distance is long. This paper studies the fading probability density functions of both fast-tracked and untracked FSO communication channels. Large-scale wave-optics simulations are conducted for both tracked and untracked lasers. In the simulations, the Kolmogorov spectrum is adopted, and it is assumed that the outer scale is infinitely large and the inner scale is negligibly small. The fading pdfs of both fast-tracked and untracked FSO channels are obtained from the simulations. Results show that the fast-tracked channel fading can be accurately modeled as gamma-distributed if receiver aperture size is smaller than the coherence radius. An analytical method is given for calculating the untracked fading pdfs of both point-like and finite-size receiver apertures from the fast-tracked fading pdf. For point-like apertures, the analytical method gives pdfs close to the well-known gamma-gamma pdfs if off-axis effects are omitted in the formulation. When off-axis effects are taken into consideration, the untracked pdfs obtained using the analytical method fit the simulation pdfs better than gamma-gamma distributions for point-like apertures, and closely fit the simulation pdfs for finite-size apertures where gamma-gamma pdfs deviate from those of the simulations significantly.

  14. Fast Three-Dimensional Single-Particle Tracking in Natural Brain Tissue

    PubMed Central

    Sokoll, Stefan; Prokazov, Yury; Hanses, Magnus; Biermann, Barbara; Tönnies, Klaus; Heine, Martin

    2015-01-01

    Observation of molecular dynamics is often biased by the optical very heterogeneous environment of cells and complex tissue. Here, we have designed an algorithm that facilitates molecular dynamic analyses within brain slices. We adjust fast astigmatism-based three-dimensional single-particle tracking techniques to depth-dependent optical aberrations induced by the refractive index mismatch so that they are applicable to complex samples. In contrast to existing techniques, our online calibration method determines the aberration directly from the acquired two-dimensional image stream by exploiting the inherent particle movement and the redundancy introduced by the astigmatism. The method improves the positioning by reducing the systematic errors introduced by the aberrations, and allows correct derivation of the cellular morphology and molecular diffusion parameters in three dimensions independently of the imaging depth. No additional experimental effort for the user is required. Our method will be useful for many imaging configurations, which allow imaging in deep cellular structures. PMID:26445447

  15. Electric eels use high-voltage to track fast-moving prey

    PubMed Central

    Catania, Kenneth C.

    2015-01-01

    Electric eels (Electrophorus electricus) are legendary for their ability to incapacitate fish, humans, and horses with hundreds of volts of electricity. The function of this output as a weapon has been obvious for centuries but its potential role for electroreception has been overlooked. Here it is shown that electric eels use high-voltage simultaneously as a weapon and for precise and rapid electrolocation of fast-moving prey and conductors. Their speed, accuracy, and high-frequency pulse rate are reminiscent of bats using a ‘terminal feeding buzz' to track insects. Eel's exhibit ‘sensory conflict' when mechanosensory and electrosensory cues are separated, striking first toward mechanosensory cues and later toward conductors. Strikes initiated in the absence of conductors are aborted. In addition to providing new insights into the evolution of strongly electric fish and showing electric eels to be far more sophisticated than previously described, these findings reveal a trait with markedly dichotomous functions. PMID:26485580

  16. Health Preemption Behind Closed Doors: Trade Agreements and Fast-Track Authority

    PubMed Central

    Crosbie, Eric; Gonzalez, Mariaelena

    2014-01-01

    Noncommunicable diseases result from consuming unhealthy products, including tobacco, which are promoted by transnational corporations. The tobacco industry uses preemption to block or reverse tobacco control policies. Preemption removes authority from jurisdictions where tobacco companies’ influence is weak and transfers it to jurisdictions where they have an advantage. International trade agreements relocate decisions about tobacco control policy to venues where there is little opportunity for public scrutiny, participation, and debate. Tobacco companies are using these agreements to preempt domestic authority over tobacco policy. Other transnational corporations that profit by promoting unhealthy foods could do the same. “Fast-track authority,” in which Congress cedes ongoing oversight authority to the President, further distances the public from the debate. With international agreements binding governments to prioritize trade over health, transparency and public oversight of the trade negotiation process is necessary to safeguard public health interests. PMID:25033124

  17. Health preemption behind closed doors: trade agreements and fast-track authority.

    PubMed

    Crosbie, Eric; Gonzalez, Mariaelena; Glantz, Stanton A

    2014-09-01

    Noncommunicable diseases result from consuming unhealthy products, including tobacco, which are promoted by transnational corporations. The tobacco industry uses preemption to block or reverse tobacco control policies. Preemption removes authority from jurisdictions where tobacco companies' influence is weak and transfers it to jurisdictions where they have an advantage. International trade agreements relocate decisions about tobacco control policy to venues where there is little opportunity for public scrutiny, participation, and debate. Tobacco companies are using these agreements to preempt domestic authority over tobacco policy. Other transnational corporations that profit by promoting unhealthy foods could do the same. "Fast-track authority," in which Congress cedes ongoing oversight authority to the President, further distances the public from the debate. With international agreements binding governments to prioritize trade over health, transparency and public oversight of the trade negotiation process is necessary to safeguard public health interests.

  18. Tracking Down a Fast Instability in the PEP-II LER

    SciTech Connect

    Wienands, U.; Akre, R.; Curry, S.; DeBarger, S.; Decker, F.J.; Ecklund, S.; Fisher, A.S.; Heifets, S.A.; Krasnykh, A.; Kulikov, A.; Novokhatski, A.; Seeman, J.; Sullivan, M.K.; Teytelman, D.; Van Winkle, D.; Yocky, G.; /SLAC

    2007-05-18

    During Run 5, the beam in the PEP-II Low Energy Ring (LER) became affected by a predominantly vertical instability with very fast growth rate of 10...60/ms and varying threshold. The coherent amplitude of the oscillation was limited to approx. 1 mm peak and would damp down over a few tens of turns, however, beam loss set in even as the amplitude signal damped, causing a beam abort. This led to the conclusion that the bunches were actually blowing up. The appearance of a 2{nu}{sub S} line in the spectrum suggested a possible head-tail nature of the instability, although chromaticity was not effective in changing the threshold. The crucial hints in tracking down the cause turned out to be vacuum activity near the rf cavities and observance of signals on the cavity probes of certain rf cavities.

  19. The Effects of the Fast Track Preventive Intervention on the Development of Conduct Disorder Across Childhood

    PubMed Central

    2013-01-01

    The impact of the Fast Track intervention on externalizing disorders across childhood was examined. Eight hundred-ninety-one early-starting children (69% male; 51% African American) were randomly assigned by matched sets of schools to intervention or control conditions. The 10-year intervention addressed parent behavior-management, child social cognitive skills, reading, home visiting, mentoring, and classroom curricula. Outcomes included psychiatric diagnoses after grades 3, 6, 9, and 12 for conduct disorder, oppositional defiant disorder, attention deficit hyperactivity disorder, and any externalizing disorder. Significant interaction effects between intervention and initial risk level indicated that intervention prevented the lifetime prevalence of all diagnoses, but only among those at highest initial risk, suggesting that targeted intervention can prevent externalizing disorders to promote the raising of healthy children. PMID:21291445

  20. The Vanderbilt University fast track to IAIMS: transition from planning to implementation.

    PubMed Central

    Stead, W W; Borden, R; Bourne, J; Giuse, D; Giuse, N; Harris, T R; Miller, R A; Olsen, A J

    1996-01-01

    Vanderbilt University Medical Center is implementing an Integrated Advanced Information Management System (IAIMS) using a fast-track approach. The elapsed time between start-up and completion of implementation will be 7.5 years. The Start-Up and Planning phases of the project are complete. The Implementation phase asks one question: How does an organization create an environment that redirects and coordinates a variety of individual activities so that they come together to provide an IAIMS? Four answers to this question are being tested. First, design resources to be "scalable"--i.e., capable of supporting enterprise-wide use. Second, provide information technology planning activities as ongoing core functions that direct local efforts. Third, design core infrastructure resources to be both reusable and expandable at the local level. Fourth, use milestones to measure progress toward selected endpoints to permit early refinement of plans and strategies. PMID:8880678

  1. Locational Sensitivity Investigation on PV Hosting Capacity and Fast Track PV Screening

    SciTech Connect

    Ding, Fei; Mather, Barry; Ainsworth, Nathan; Gotseff, Peter; Baker, Kyri

    2016-05-05

    A 15% PV penetration threshold is commonly used by utilities to define photovoltaic (PV) screening methods where PV penetration is defined as the ratio of total solar PV capacity on a line section to peak load. However, this method doesn't take into account PV locational impact or feeder characteristics that could strongly change the feeder's capability to host PVs. This paper investigates the impact of PV location and phase connection type on PV hosting capacity, and then proposes a fast-track PV screening approach that leverages various PV hosting capacity metric responding to different PV locations and types. The proposed study could help utilities to evaluate PV interconnection requests and also help increase the PV hosting capacity of distribution feeders without adverse impacts on system voltages.

  2. Fast cine-magnetic resonance imaging point tracking for prostate cancer radiation therapy planning

    NASA Astrophysics Data System (ADS)

    Dowling, J.; Dang, K.; Fox, Chris D.; Chandra, S.; Gill, Suki; Kron, T.; Pham, D.; Foroudi, F.

    2014-03-01

    The analysis of intra-fraction organ motion is important for improving the precision of radiation therapy treatment delivery. One method to quantify this motion is for one or more observers to manually identify anatomic points of interest (POIs) on each slice of a cine-MRI sequence. However this is labour intensive and inter- and intra- observer variation can introduce uncertainty. In this paper a fast method for non-rigid registration based point tracking in cine-MRI sagittal and coronal series is described which identifies POIs in 0.98 seconds per sagittal slice and 1.35 seconds per coronal slice. The manual and automatic points were highly correlated (r>0.99, p<0.001) for all organs and the difference generally less than 1mm. For prostate planning peristalsis and rectal gas can result in unpredictable out of plane motion, suggesting the results may require manual verification.

  3. Studies of the possibility to use Gas Pixel Detector as a fast trigger tracking device

    NASA Astrophysics Data System (ADS)

    Sinev, N.; Bashindzhagyan, G.; Korotkova, N.; Romaniouk, A.; Tikhomirov, V.

    2016-02-01

    Gas Pixel Detector (GPD) technology offers new possibilities, which make them very attractive for application in existing and future accelerator experiments and beyond. GPDs combine advantages of silicon and gaseous detectors. They can be produced radiation hard and with low power consumption using relatively cheap technology. Low capacitance of the individual pixel channel allows us to obtain a large signal to noise ratio. Using a time projection method for GPD readout one obtains 3D track image with precise coordinate (31 µm) and angular information (0.40°). This feature would allow us to achieve performance of one GPD layer equal to a few layers of silicon detectors. Implementation of a fast readout and data processing at the front-end level allows one to reconstruct a track segment in less than 1 μs, and to use this information for the first level trigger generation. The relevant algorithms of data acquisition and analysis are described and the results of simulations are presented in this paper.

  4. Detection of a faint fast-moving near-Earth asteroid using the synthetic tracking technique

    SciTech Connect

    Zhai, Chengxing; Shao, Michael; Nemati, Bijan; Werne, Thomas; Zhou, Hanying; Turyshev, Slava G.; Sandhu, Jagmit; Hallinan, Gregg; Harding, Leon K.

    2014-09-01

    We report a detection of a faint near-Earth asteroid (NEA) using our synthetic tracking technique and the CHIMERA instrument on the Palomar 200 inch telescope. With an apparent magnitude of 23 (H = 29, assuming detection at 20 lunar distances), the asteroid was moving at 6.°32 day{sup –1} and was detected at a signal-to-noise ratio (S/N) of 15 using 30 s of data taken at a 16.7 Hz frame rate. The detection was confirmed by a second observation 77 minutes later at the same S/N. Because of its high proper motion, the NEA moved 7 arcsec over the 30 s of observation. Synthetic tracking avoided image degradation due to trailing loss that affects conventional techniques relying on 30 s exposures; the trailing loss would have degraded the surface brightness of the NEA image on the CCD down to an approximate magnitude of 25 making the object undetectable. This detection was a result of our 12 hr blind search conducted on the Palomar 200 inch telescope over two nights, scanning twice over six (5.°3 × 0.°046) fields. Detecting only one asteroid is consistent with Harris's estimates for the distribution of the asteroid population, which was used to predict a detection of 1.2 NEAs in the H-magnitude range 28-31 for the two nights. The experimental design, data analysis methods, and algorithms are presented. We also demonstrate milliarcsecond-level astrometry using observations of two known bright asteroids on the same system with synthetic tracking. We conclude by discussing strategies for scheduling observations to detect and characterize small and fast-moving NEAs using the new technique.

  5. fsclean: Faraday Synthesis CLEAN imager

    NASA Astrophysics Data System (ADS)

    Bell, M. R.; Ensslin, T. A.

    2015-06-01

    Fsclean produces 3D Faraday spectra using the Faraday synthesis method, transforming directly from multi-frequency visibility data to the Faraday depth-sky plane space. Deconvolution is accomplished using the CLEAN algorithm, and the package includes Clark and Högbom style CLEAN algorithms. Fsclean reads in MeasurementSet visibility data and produces HDF5 formatted images; it handles images and data of arbitrary size, using scratch HDF5 files as buffers for data that is not being immediately processed, and is limited only by available disk space.

  6. Hysteretic Faraday waves

    NASA Astrophysics Data System (ADS)

    Périnet, Nicolas; Falcón, Claudio; Chergui, Jalel; Shin, Seungwon; Juric, Damir

    2016-11-01

    We study with numerical simulations the two-dimensional Faraday waves in two immiscible incompressible fluids when the lower fluid layer is shallow. After the appearance of the well known subharmonic stationary waves, a further instability is observed while the control parameter passes a secondary threshold. A new state then arises, composed of stationary waves with about twice the original pattern amplitude. The bifurcation presents hysteresis: there exists a finite range of the control parameter in which both states are stable. By means of a simple stress balance, we show that a change of the shear stress can explain this hysteresis. Our predictions based on this model are in agreement with our numerical results. Project funded by FONDECYT Grants 1130354, 3140522 and the National Research Foundation of Korea (NRF- 2014R1A2A1A11051346). Computations supported by the supercomputing infrastructures of the NLHPC (ECM-02) and GENCI (IDRIS).

  7. Fast pattern recognizer for autonomous target recognition and tracking for advanced naval attack missiles

    NASA Astrophysics Data System (ADS)

    Hastbacka, Al

    2001-10-01

    A FPR System under development for the Naval Air Warfare Center, China Lake, CA is funded under a SBIR, Phase II contract as an automatic target recognizer and tracker candidate for Navy fast-reaction, subsonic and supersonic, stand-off weapons. The FPR will autonomously detect, identify, correlate, and track complex surface ship and land based targets in hostile, high-clutter environments in real time. The novel FPR system is proven technology that uses an electronic implementation analogous to an optical correlator system, where the Fourier transform of the incoming image is compared against known target images stored as matched filter templates. FPR demonstrations show that unambiguous target identification is achievable in a ninety-five percent fog obscuration for over ninety-percent of target images tested. The FPR technology employs an acoustic dispersive delay line (DDL) to achieve ultra-fast image correlations in 90 microseconds or 11,000 correlations per second. The massively scalable FPR design is capable of achieving processing speeds of an order of magnitude faster using available ASIC technology. Key benefits of the FPR are dramatically reduced power, size, weight, and cost with increased durability, robustness, and performance - which makes the FPR ideal for onboard missile applications.

  8. Constructing Fast Carrier Tracks into Flexible Perovskite Photodetectors To Greatly Improve Responsivity.

    PubMed

    Li, Xiaoming; Yu, Dejian; Chen, Jun; Wang, Yue; Cao, Fei; Wei, Yi; Wu, Ye; Wang, Lin; Zhu, Ying; Sun, Zhiguo; Ji, Jianping; Shen, Yalong; Sun, Handong; Zeng, Haibo

    2017-02-28

    Intrinsically high mobility and large absorption coefficient endow inorganic halide perovskites (IHPs) with great promise for high-performance photodetectors (PDs), which, however, are being hindered by the low carrier extraction and transport efficiency of the solution assembled films. Here, we report on a general strategy to enhance the perovskite film conductivity that carbon nanotubes (CNTs) conductive nanonets are constructed from to provide fast carrier tracks. Resultantly, the CsPbBr3 nanosheet/CNT composite films exhibit both high light harvesting and high conductivity, such advantages are demonstrated by the high performances of corresponding planar PDs. Specifically, the highest external quantum efficiency (EQE) of 7488% and the highest responsivity of 31.1 A W(-1) under a bias of 10 V among IHP PDs with planar structure are achieved, which are almost 125-fold over the previous best results. Besides, the efficient charge extraction and transport also remarkably contribute to the fast response speed where a rise time of 16 μs is achieved, which is also superior to state-of-the-art IHP PDs. Furthermore, the composite films exhibit impressive flexibility due to the ultrathin 2D and 1D structural characteristic of perovskites and CNTs. By deploying the PD as a point-like detector, we acquire clear images. The results indicate the promising potentials of the perovskite/CNT composites for solution and ambient condition processed flexible devices, and this strategy is general for all kinds of perovskite optoelectronic devices including photodetectors, phototransistors, and even LEDs.

  9. Faraday instability of a spherical drop

    NASA Astrophysics Data System (ADS)

    Ebo Adou, A.; Tuckerman, Laurette; Shin, Seungwon; Chergui, Jalel; Juric, Damir

    2014-11-01

    A liquid drop subjected to an oscillatory radial force comprises a spherical version of the Faraday instability, with a subharmonic response which is half of the forcing frequency. The time-dependent shape of the drop and the velocity field in and around it are calculated using BLUE, a code based on a hybrid Front Tracking/Level-set algorithm for Lagrangian tracking of arbitrarily deformable phase interfaces. We compare this shape with the spherical harmonic selected at onset, calculated by adapting the Floquet stability analysis of Kumar and Tuckerman to a spherical geometry. We interpret the shape in light of theoretical results by Busse, Matthews and others concerning pattern formation in the presence of O(3) symmetry.

  10. Faraday anomalous dispersion optical tuners

    NASA Technical Reports Server (NTRS)

    Wanninger, P.; Valdez, E. C.; Shay, T. M.

    1992-01-01

    Common methods for frequency stabilizing diode lasers systems employ gratings, etalons, optical electric double feedback, atomic resonance, and a Faraday cell with low magnetic field. Our method, the Faraday Anomalous Dispersion Optical Transmitter (FADOT) laser locking, is much simpler than other schemes. The FADOT uses commercial laser diodes with no antireflection coatings, an atomic Faraday cell with a single polarizer, and an output coupler to form a compound cavity. This method is vibration insensitive, thermal expansion effects are minimal, and the system has a frequency pull in range of 443.2 GHz (9A). Our technique is based on the Faraday anomalous dispersion optical filter. This method has potential applications in optical communication, remote sensing, and pumping laser excited optical filters. We present the first theoretical model for the FADOT and compare the calculations to our experimental results.

  11. Faraday imaging at high temperatures

    DOEpatents

    Hackel, L.A.; Reichert, P.

    1997-03-18

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid. 3 figs.

  12. Faraday imaging at high temperatures

    DOEpatents

    Hackel, Lloyd A.; Reichert, Patrick

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid.

  13. Catalyzing Country Ownership and Aid Effectiveness: Role of the Education for All-Fast Track Initiative Catalytic Fund

    ERIC Educational Resources Information Center

    Bashir, Sajitha

    2009-01-01

    This article examines the contribution of the Education for All-Fast Track Initiative (EFA-FTI) global partnership in strengthening aid effectiveness in the education sector, and specifically how the implementation modalities of the EFA-FTI Catalytic Fund (CF) have contributed to this strengthening. The empirical findings are based on a review…

  14. Fast-track extreme event attribution: How fast can we disentangle thermodynamic (forced) and dynamic (internal) contributions?

    NASA Astrophysics Data System (ADS)

    Haustein, Karsten; Otto, Friederike; Uhe, Peter; Allen, Myles; Cullen, Heidi

    2016-04-01

    provide sufficient guidance to determine the dynamic contribution to the event on the basis of monthly mean values. No such link can be made (North Atlantic/Western Europe region) for shorter time-scales, unless the observed state of the circulation is taken as reference for the model analysis (e.g. Christidis et al. 2014). We present results from our most recent attribution analysis for the December 2015 UK floods (Storm Desmond and Eva), during which we find a robust teleconnection link between Pacific SSTs and North Atlantic Jetstream anomalies. This is true for both experiments, with forecast and observed SSTs. We propose a fast and simple analysis method based on the comparison of current climatological circulation patterns with actual and natural conditions. Alternative methods are discussed and analysed regarding their potential for fast-track attribution of the role of dynamics. Also, we briefly revisit the issue of internal vs forced dynamic contributions.

  15. Fast Variable Structure Stochastic Automaton for Discovering and Tracking Spatiotemporal Event Patterns.

    PubMed

    Zhang, Junqi; Wang, Yuheng; Wang, Cheng; Zhou, MengChu

    2017-04-05

    Discovering and tracking spatiotemporal event patterns have many applications. For example, in a smart-home project, a set of spatiotemporal pattern learning automata are used to monitor a user's repetitive activities, by which the home's automaticity can be promoted while some of his/her burdens can be reduced. Existing algorithms for spatiotemporal event pattern recognition in dynamic noisy environment are based on fixed structure stochastic automata whose state transition function is fixed and predesigned to guarantee their immunity to noise. However, such design is conservative because it needs continuous and identical feedbacks to converge, thus leading to its very low convergence rate. In many real-life applications, such as ambient assisted living, consecutive nonoccurrences of an elder resident's routine activities should be treated with an alert as quickly as possible. On the other hand, no alert should be output even for some occurrences in order to diminish the effects caused by noise. Clearly, confronting a pattern's change, slow speed and low accuracy may degrade a user's life security. This paper proposes a fast and accurate leaning automaton based on variable structure stochastic automata to satisfy the realistic requirements for both speed and accuracy. Bias toward alert is necessary for elder residents while the existing method can only support the bias toward ``no alert.'' This paper introduces a method to allow bias toward alert or no alert to meet a user's specific bias requirement. Experimental results show its better performance than the state-of-the-art methods.

  16. Mass tracking and material accounting in the Integral Fast Reactor (IFR)

    SciTech Connect

    Orechwa, Y.; Adams, C.H.; White, A.M.

    1991-01-01

    The Integral Fast Reactor (IFR) is a generic advanced liquid metal cooled reactor concept being developed at Argonne National Laboratory (ANL). There are a number of technical features of the IFR which contribute to its potential as a next-generation reactor. These are associated with large safety margins with regard to off-normal events involving the heat transport system, and the use of metallic fuel which makes possible the utilization of innovative fuel cycle processes. The latter feature permits fuel cycle closure the compact, low-cost reprocessing facilities, collocated with the reactor plant. These primary features are being demonstrated in the facilities at ANL-West, utilizing Experimental Breeder Reactor 2 and the associated Fuel Cycle Facility (FCF) as an IFR prototype. The demonstration of this IFR prototype includes the design and implementation of the Mass-Tracking System (MTG). In this system, data from the operations of the FCF, including weights and batch-process parameters, are collected and maintained by the MTG running on distributed workstations. The components of the MTG System include: (1) an Oracle database manager with a Fortran interface, (2) a set of MTG Tasks'' which collect, manipulate and report data, (3) a set of MTG Terminal Sessions'' which provide some interactive control of the Tasks, and (4) a set of servers which manage the Tasks and which provide the communications link between the MTG System and Operator Control Stations, which control process equipment and monitoring devices within the FCF.

  17. [Anxiety in patients undergoing fast-track knee arthroplasty in the light of recent literature].

    PubMed

    Ziętek, Paweł; Ziętek, Joanna; Szczypiór, Karina

    2014-01-01

    The rapid progress in knee implants technology and operational techniques go together with more and more modem medical programs, designed to optimize the patients' care and shorten their stay in hospital. However, this does not guarantee any elimination ofperioperative stress in patients. Anxiety is a negative emotional state arising from stressful circumstances accompanied by activation of the autonomous nervous system. Anxiety causes negative physiological changes, including wound healing, resistance to anesthetic induction, it is associated with an increased perioperative pain and prolong recovery period. The purpose of this work is to present the current state of knowledge on the preoperative anxiety and discuss its impact on pain and other parameters in patients undergoing fast-track arthroplasty of big joints. The work also shows selected issues of anxiety pathomechanism, and actual methods reducing preoperative anxiety in hospitalized patients. The common prevalence of anxiety in patients undergoing surgery induces the attempt to routinely identify patients with higher anxiety, which may be a predictive factor of worse results after TKA. Undertaking widely understood psychological support in these patients before and after the operation could be a favorable element, which would influence thefinal result of the treatment of patients after big joints arthroplasties.

  18. Pivotal role of ATP in macrophages fast tracking wound repair and regeneration.

    PubMed

    Kotwal, Girish J; Sarojini, Harshini; Chien, Sufan

    2015-09-01

    Chronic wounds occurring during aging or diabetes pose a significant burden to patients. The classical four-phase wound healing process has a 3-6 day lag before granulation starts to appear and it requires an intermediate step of activation of resident fibroblasts during the remodeling phase for production of collagen. This brief communication discusses published articles that demonstrate how the entire wound healing process can be fast tracked by intracellular ATP delivery, which triggers a novel pathway where alternatively activated macrophages play absolutely critical and central roles. This novel pathway involves an increase in proinflammatory cytokines (TNF, IL-1β, IL-6) and a chemokine (MCP-1) release. This is followed by activation of purinergic receptor (a family of plasma membrane receptors found in almost all mammalian cells), production of platelets and platelet microparticles, and activation of ATP-dependent chromatin remodeling enzymes. The end result is a massive influx and in situ proliferation of macrophages, increases in vascular endothelial growth factors that promote neovascularization, and most prominently, the direct production of collagen.

  19. Active Faraday optical frequency standard.

    PubMed

    Zhuang, Wei; Chen, Jingbiao

    2014-11-01

    We propose the mechanism of an active Faraday optical clock, and experimentally demonstrate an active Faraday optical frequency standard based on narrow bandwidth Faraday atomic filter by the method of velocity-selective optical pumping of cesium vapor. The center frequency of the active Faraday optical frequency standard is determined by the cesium 6 (2)S(1/2) F=4 to 6 (2)P(3/2) F'=4 and 5 crossover transition line. The optical heterodyne beat between two similar independent setups shows that the frequency linewidth reaches 281(23) Hz, which is 1.9×10(4) times smaller than the natural linewidth of the cesium 852-nm transition line. The maximum emitted light power reaches 75 μW. The active Faraday optical frequency standard reported here has advantages of narrow linewidth and reduced cavity pulling, which can readily be extended to other atomic transition lines of alkali and alkaline-earth metal atoms trapped in optical lattices at magic wavelengths, making it useful for new generation of optical atomic clocks.

  20. Traditional healers and the "Fast-Track" HIV response: is success possible without them?

    PubMed

    Leclerc-Madlala, Suzanne; Green, Edward; Hallin, Mary

    2016-07-01

    The rapid scale-up of effective HIV prevention strategies is a central theme of the post-2015 health and development agenda. All major global HIV and AIDS funders have aligned their policies and plans to achieve sharp reductions in new HIV infections and reach epidemic control by 2030. In these "fast-track" plans, increased antiretroviral treatment coverage and the attainment of viral suppression are pivotal, and there is firm recognition of the need for countries to mobilise more domestic resources and build stronger community clinic systems. There is little in these bold plans, however, to suggest that the now 30-year-old call by the World Health Organization (WHO) and other organisations to establish systematic collaborations with the traditional health sector will finally be heeded. In the context of sub-Saharan Africa's HIV epidemic, a significant body of literature demonstrates the critical role that traditional healers can play in improving the success of health programmes, including those for HIV prevention. This paper provides a brief history of collaboration with traditional healers for HIV followed by a description of several successful collaborations and discussion of key elements for success. We argue that the traditional health sector is a major resource that has yet to be sufficiently mobilised against HIV. As we shift from a short-term HIV response to a longer-term and more sustainable response, there is an urgent need to accelerate efforts to leverage and partner with the hundreds of thousands of traditional health practitioners who are already providing health services in communities. Failure to better attune our work to the medical pluralism of communities affected by HIV will continue to hinder HIV programming success and help assure that ambitious post-2015 HIV prevention and control goals are not realised.

  1. A fusion nuclear science facility for a fast-track path to DEMO

    DOE PAGES

    Garofalo, A. M.; Abdou, M. A.; Canik, John M.; ...

    2014-04-24

    An accelerated fusion energy development program, a fast-track approach, requires proceeding with a nuclear and materials testing program in parallel with research on burning plasmas, ITER. A Fusion Nuclear Science Facility (FNSF) would address many of the key issues that need to be addressed prior to DEMO, including breeding tritium and completing the fuel cycle, qualifying nuclear materials for high fluence, developing suitable materials for the plasma-boundary interface, and demonstrating power extraction. The Advanced Tokamak (AT) is a strong candidate for an FNSF as a consequence of its mature physics base, capability to address the key issues, and the directmore » relevance to an attractive target power plant. The standard aspect ratio provides space for a solenoid, assuring robust plasma current initiation,and for an inboard blanket, assuring robust tritium breeding ratio (TBR) >1 for FNSF tritium self-sufficiency and building of inventory needed to start up DEMO. An example design point gives a moderate sized Cu-coil device with R/a = 2.7 m/0.77 κ = 2.3, BT= 5.4 T, IP = 6.6 MA, βN = 2.75, Pfus = 127 MW. The modest bootstrap fraction of fBS = 0.55 provides an opportunity to develop steady state with sufficient current drive for adequate control. Lastly, proceeding with a FNSF in parallel with ITER provides a strong basis to begin construction of DEMO upon the achievement of Q ~ 10 in ITER.« less

  2. A fusion nuclear science facility for a fast-track path to DEMO

    SciTech Connect

    Garofalo, A. M.; Abdou, M. A.; Canik, John M.; Chan, Vincent S.; Hyatt, A. W.; Hill, D. N.; Morley, N. B.; Navratil, G. A.; Sawan, M. E.; Taylor, T. S.; Wong, C. P. C.; Wu, W.; Ying, Alice

    2014-04-24

    An accelerated fusion energy development program, a fast-track approach, requires proceeding with a nuclear and materials testing program in parallel with research on burning plasmas, ITER. A Fusion Nuclear Science Facility (FNSF) would address many of the key issues that need to be addressed prior to DEMO, including breeding tritium and completing the fuel cycle, qualifying nuclear materials for high fluence, developing suitable materials for the plasma-boundary interface, and demonstrating power extraction. The Advanced Tokamak (AT) is a strong candidate for an FNSF as a consequence of its mature physics base, capability to address the key issues, and the direct relevance to an attractive target power plant. The standard aspect ratio provides space for a solenoid, assuring robust plasma current initiation,and for an inboard blanket, assuring robust tritium breeding ratio (TBR) >1 for FNSF tritium self-sufficiency and building of inventory needed to start up DEMO. An example design point gives a moderate sized Cu-coil device with R/a = 2.7 m/0.77 κ = 2.3, BT= 5.4 T, IP = 6.6 MA, βN = 2.75, Pfus = 127 MW. The modest bootstrap fraction of fBS = 0.55 provides an opportunity to develop steady state with sufficient current drive for adequate control. Lastly, proceeding with a FNSF in parallel with ITER provides a strong basis to begin construction of DEMO upon the achievement of Q ~ 10 in ITER.

  3. Fast-track rapid warfarin reversal for elective surgery: extending the efficacy profile to high-risk patients with cancer.

    PubMed

    Byrne, T J; Riedel, B; Ismail, H M; Heriot, A; Dauer, R; Westerman, D; Seymour, J F; Kenchington, K; Burbury, K

    2015-11-01

    Periprocedural management of patients on long-term warfarin therapy remains a common and important clinical issue, with little high-quality data to guide this complex process. The current accepted practice is cessation of warfarin five days preoperatively, but this is not without risk and can be complicated, particularly if bridging is required. An alternative method utilising low-dose intravenous vitamin K the day before surgery has been shown previously to be efficacious, safe and convenient in an elective surgical population receiving chronic warfarin therapy. The efficacy and utility of this 'fast-track' warfarin reversal protocol in surgical patients with cancer, who were at high risk of both thromboembolism and bleeding was investigated in a prospective, single-arm study at a dedicated cancer centre. Seventy-one patients underwent 82 episodes of fast-track warfarin reversal (3 mg intravenous vitamin K 18 to 24 hours before surgery). No patient suffered an adverse reaction to intravenous vitamin K, all but one achieved an International Normalized Ratio =1.5 on the day of surgery, and no surgery was deferred. Assays of vitamin K-dependent factor levels pre- and post-vitamin K demonstrated restoration of functional activity to within an acceptable range for surgical haemostasis. While this alternative method requires further validation in a larger prospective randomised study, we have now extended our use of fast-track warfarin reversal using vitamin K to patients with cancer, on the basis of our experience of its safety, convenience, reliability and efficacy.

  4. The Implementation of the Fast Track Program: An Example of a Large-Scale Prevention Science Efficacy Trial

    PubMed Central

    2009-01-01

    In 1990, the Fast Track Project was initiated to evaluate the feasibility and effectiveness of a comprehensive, multicomponent prevention program targeting children at risk for conduct disorders in four demographically diverse American communities (Conduct Problems Prevention Research Group [CPPRG], 1992). Representing a prevention science approach toward community-based preventive intervention, the Fast Track intervention design was based upon the available data base elucidating the epidemiology of risk for conduct disorder and suggesting key causal developmental influences (R. P. Weissberg & M. T. Greenberg, 1998). Critical questions about this approach to prevention center around the extent to which such a science-based program can be effective at (1) engaging community members and stakeholders, (2) maintaining intervention fidelity while responding appropriately to the local norms and needs of communities that vary widely in their demographic and cultural/ethnic composition, and (3) maintaining community engagement in the long-term to support effective and sustainable intervention dissemination. This paper discusses these issues, providing examples from the Fast Track project to illustrate the process of program implementation and the evidence available regarding the success of this science-based program at engaging communities in sustainable and effective ways as partners in prevention programming. PMID:11930968

  5. Various Paths to Faraday's Law

    ERIC Educational Resources Information Center

    Redzic, Dragan V.

    2008-01-01

    In a recent note, the author presented a derivation of Faraday's law of electromagnetic induction for a closed filamentary circuit C(t) which is moving at relativistic velocities and also changing its shape as it moves via the magnetic vector potential. Recently, Kholmetskii et al, while correcting an error in an equation, showed that it can be…

  6. Faraday's first dynamo: A retrospective

    NASA Astrophysics Data System (ADS)

    Smith, Glenn S.

    2013-12-01

    In the early 1830s, Michael Faraday performed his seminal experimental research on electromagnetic induction, in which he created the first electric dynamo—a machine for continuously converting rotational mechanical energy into electrical energy. His machine was a conducting disc, rotating between the poles of a permanent magnet, with the voltage/current obtained from brushes contacting the disc. In his first dynamo, the magnetic field was asymmetric with respect to the axis of the disc. This is to be contrasted with some of his later symmetric designs, which are the ones almost invariably discussed in textbooks on electromagnetism. In this paper, a theoretical analysis is developed for Faraday's first dynamo. From this analysis, the eddy currents in the disc and the open-circuit voltage for arbitrary positioning of the brushes are determined. The approximate analysis is verified by comparing theoretical results with measurements made on an experimental recreation of the dynamo. Quantitative results from the analysis are used to elucidate Faraday's qualitative observations, from which he learned so much about electromagnetic induction. For the asymmetric design, the eddy currents in the disc dissipate energy that makes the dynamo inefficient, prohibiting its use as a practical generator of electric power. Faraday's experiments with his first dynamo provided valuable insight into electromagnetic induction, and this insight was quickly used by others to design practical generators.

  7. A Mobile Phone Faraday Cage

    ERIC Educational Resources Information Center

    French, M. M. J.

    2011-01-01

    A Faraday cage is an interesting physical phenomenon where an electromagnetic wave can be excluded from a volume of space by enclosure with an electrically conducting material. The practical application of this in the classroom is to block the signal to a mobile phone by enclosing it in a metal can. The background of the physics behind this is…

  8. Faraday's Law and Seawater Motion

    ERIC Educational Resources Information Center

    De Luca, R.

    2010-01-01

    Using Faraday's law, one can illustrate how an electromotive force generator, directly utilizing seawater motion, works. The conceptual device proposed is rather simple in its components and can be built in any high school or college laboratory. The description of the way in which the device generates an electromotive force can be instructive not…

  9. Faraday Cage Protects Against Lightning

    NASA Technical Reports Server (NTRS)

    Jafferis, W.; Hasbrouck, R. T.; Johnson, J. P.

    1992-01-01

    Faraday cage protects electronic and electronically actuated equipment from lightning. Follows standard lightning-protection principles. Whether lightning strikes cage or cables running to equipment, current canceled or minimized in equipment and discharged into ground. Applicable to protection of scientific instruments, computers, radio transmitters and receivers, and power-switching equipment.

  10. Building a better Faraday cage

    NASA Astrophysics Data System (ADS)

    MartinAlfven; Wright, David; skocpol; Rounce, Graham; Richfield, Jon; W, Nick; wheelsonfire

    2015-11-01

    In reply to the physicsworld.com news article “Are Faraday cages less effective than previously thought?” (15 September, http://ow.ly/SfklO), about a study that indicated, based on mathematical modelling, that conducting wire-mesh cages may not be as good at excluding electromagnetic radiation as is commonly assumed.

  11. Exhausting Attentional Tracking Resources with a Single Fast-Moving Object

    ERIC Educational Resources Information Center

    Holcombe, Alex O.; Chen, Wei-Ying

    2012-01-01

    Driving on a busy road, eluding a group of predators, or playing a team sport involves keeping track of multiple moving objects. In typical laboratory tasks, the number of visual targets that humans can track is about four. Three types of theories have been advanced to explain this limit. The fixed-limit theory posits a set number of attentional…

  12. Radiation-hardened fast acquisition/weak signal tracking system and method

    NASA Technical Reports Server (NTRS)

    Winternitz, Luke (Inventor); Boegner, Gregory J. (Inventor); Sirotzky, Steve (Inventor)

    2009-01-01

    A global positioning system (GPS) receiver and method of acquiring and tracking GPS signals comprises an antenna adapted to receive GPS signals; an analog radio frequency device operatively connected to the antenna and adapted to convert the GPS signals from an analog format to a digital format; a plurality of GPS signal tracking correlators operatively connected to the analog RF device; a GPS signal acquisition component operatively connected to the analog RF device and the plurality of GPS signal tracking correlators, wherein the GPS signal acquisition component is adapted to calculate a maximum vector on a databit correlation grid; and a microprocessor operatively connected to the plurality of GPS signal tracking correlators and the GPS signal acquisition component, wherein the microprocessor is adapted to compare the maximum vector with a predetermined correlation threshold to allow the GPS signal to be fully acquired and tracked.

  13. Fast and Accurate Cell Tracking by a Novel Optical-Digital Hybrid Method

    NASA Astrophysics Data System (ADS)

    Torres-Cisneros, M.; Aviña-Cervantes, J. G.; Pérez-Careta, E.; Ambriz-Colín, F.; Tinoco, Verónica; Ibarra-Manzano, O. G.; Plascencia-Mora, H.; Aguilera-Gómez, E.; Ibarra-Manzano, M. A.; Guzman-Cabrera, R.; Debeir, Olivier; Sánchez-Mondragón, J. J.

    2013-09-01

    An innovative methodology to detect and track cells using microscope images enhanced by optical cross-correlation techniques is proposed in this paper. In order to increase the tracking sensibility, image pre-processing has been implemented as a morphological operator on the microscope image. Results show that the pre-processing process allows for additional frames of cell tracking, therefore increasing its robustness. The proposed methodology can be used in analyzing different problems such as mitosis, cell collisions, and cell overlapping, ultimately designed to identify and treat illnesses and malignancies.

  14. Fast TPC Online Tracking on GPUs and Asynchronous Data Processing in the ALICE HLT to facilitate Online Calibration

    NASA Astrophysics Data System (ADS)

    Rohr, David; Gorbunov, Sergey; Krzewicki, Mikolaj; Breitner, Timo; Kretz, Matthias; Lindenstruth, Volker

    2015-12-01

    ALICE (A Large Heavy Ion Experiment) is one of the four major experiments at the Large Hadron Collider (LHC) at CERN, which is today the most powerful particle accelerator worldwide. The High Level Trigger (HLT) is an online compute farm of about 200 nodes, which reconstructs events measured by the ALICE detector in real-time. The HLT uses a custom online data-transport framework to distribute data and workload among the compute nodes. ALICE employs several calibration-sensitive subdetectors, e.g. the TPC (Time Projection Chamber). For a precise reconstruction, the HLT has to perform the calibration online. Online- calibration can make certain Offline calibration steps obsolete and can thus speed up Offline analysis. Looking forward to ALICE Run III starting in 2020, online calibration becomes a necessity. The main detector used for track reconstruction is the TPC. Reconstructing the trajectories in the TPC is the most compute-intense step during event reconstruction. Therefore, a fast tracking implementation is of great importance. Reconstructed TPC tracks build the basis for the calibration making a fast online-tracking mandatory. We present several components developed for the ALICE High Level Trigger to perform fast event reconstruction and to provide features required for online calibration. As first topic, we present our TPC tracker, which employs GPUs to speed up the processing, and which bases on a Cellular Automaton and on the Kalman filter. Our TPC tracking algorithm has been successfully used in 2011 and 2012 in the lead-lead and the proton-lead runs. We have improved it to leverage features of newer GPUs and we have ported it to support OpenCL, CUDA, and CPUs with a single common source code. This makes us vendor independent. As second topic, we present framework extensions required for online calibration. The extensions, however, are generic and can be used for other purposes as well. We have extended the framework to support asynchronous compute

  15. Faraday anomalous dispersion optical filters

    NASA Technical Reports Server (NTRS)

    Shay, T. M.; Yin, B.; Alvarez, L. S.

    1993-01-01

    The effect of Faraday anomalous dispersion optical filters on infrared and blue transitions of some alkali atoms is calculated. A composite system is designed to further increase the background noise rejection. The measured results of the solar background rejection and image quality through the filter are presented. The results show that the filter may provide high transmission and high background noise rejection with excellent image quality.

  16. A mobile phone Faraday cage

    NASA Astrophysics Data System (ADS)

    French, M. M. J.

    2011-05-01

    A Faraday cage is an interesting physical phenomenon where an electromagnetic wave can be excluded from a volume of space by enclosure with an electrically conducting material. The practical application of this in the classroom is to block the signal to a mobile phone by enclosing it in a metal can. The background of the physics behind this is described in some detail, and this is followed by a explanation of some demonstrations and experiments which I have used.

  17. Deconvolving Current from Faraday Rotation Measurement

    SciTech Connect

    Stephen E. Mitchell

    2008-02-01

    In this paper, a unique software program is reported which automatically decodes the Faraday rotation signal into a time-dependent current representation. System parameters, such as the Faraday fiber’s Verdet constant and number of loops in the sensor, are the only user-interface inputs. The central aspect of the algorithm utilizes a short-time Fourier transform, which reveals much of the Faraday rotation measurement’s implicit information necessary for unfolding the dynamic current measurement.

  18. Can Genetics Predict Response to Complex Behavioral Interventions? Evidence from a Genetic Analysis of the Fast Track Randomized Control Trial.

    PubMed

    Albert, Dustin; Belsky, Daniel W; Crowley, D Max; Latendresse, Shawn J; Aliev, Fazil; Riley, Brien; Sun, Cuie; Dick, Danielle M; Dodge, Kenneth A

    2015-01-01

    Early interventions are a preferred method for addressing behavioral problems in high-risk children, but often have only modest effects. Identifying sources of variation in intervention effects can suggest means to improve efficiency. One potential source of such variation is the genome. We conducted a genetic analysis of the Fast Track randomized control trial, a 10-year-long intervention to prevent high-risk kindergarteners from developing adult externalizing problems including substance abuse and antisocial behavior. We tested whether variants of the glucocorticoid receptor gene NR3C1 were associated with differences in response to the Fast Track intervention. We found that in European-American children, a variant of NR3C1 identified by the single-nucleotide polymorphism rs10482672 was associated with increased risk for externalizing psychopathology in control group children and decreased risk for externalizing psychopathology in intervention group children. Variation in NR3C1 measured in this study was not associated with differential intervention response in African-American children. We discuss implications for efforts to prevent externalizing problems in high-risk children and for public policy in the genomic era.

  19. Wave-particle interaction in the Faraday waves.

    PubMed

    Francois, N; Xia, H; Punzmann, H; Shats, M

    2015-10-01

    Wave motion in disordered Faraday waves is analysed in terms of oscillons or quasi-particles. The motion of these oscillons is measured using particle tracking tools and it is compared with the motion of fluid particles on the water surface. Both the real floating particles and the oscillons, representing the collective fluid motion, show Brownian-type dispersion exhibiting ballistic and diffusive mean squared displacement at short and long times, respectively. While the floating particles motion has been previously explained in the context of two-dimensional turbulence driven by Faraday waves, no theoretical description exists for the random walk type motion of oscillons. It is found that the r.m.s velocity ⟨μ̃(osc)⟩(rms) of oscillons is directly related to the turbulent r.m.s. velocity ⟨μ̃⟩(rms) of the fluid particles in a broad range of vertical accelerations. The measured ⟨μ̃(osc)⟩(rms) accurately explains the broadening of the frequency spectra of the surface elevation observed in disordered Faraday waves. These results suggest that 2D turbulence is the driving force behind both the randomization of the oscillons motion and the resulting broadening of the wave frequency spectra. The coupling between wave motion and hydrodynamic turbulence demonstrated here offers new perspectives for predicting complex fluid transport from the knowledge of wave field spectra and vice versa.

  20. Analysis of Tracking Measuring Method of Focus Cabin of Five-hundred-meter Aperture Spherical radio Telescope(FAST)

    NASA Astrophysics Data System (ADS)

    Yuan, Hui; Zhu, Lichun

    2015-08-01

    FAST (Five-hundred-meter Aperture Spherical radio Telescope) project is one of the Chinese mega-Science Projects to build the largest single dish radio telescope in the world. FAST has three outstanding innovation aspects: in the karst depression which is large to host the 500-meter telescope, an active main reflector correcting for spherical aberration on the ground to achieve a full polarization is being built, the light-weight feed focus cabin in which a parallel robot as a secondary adjustable system to move with high precision is driven by cables and servomechanism plus. The part of main reflector which is illuminated by the feed is continually adjusted to fit the paraboloid of revolution in real time when tracking the radio source. How to get high precise real-time feedback data of moving focus cabin’s position when tracking the source is one of the crucial problems for the astronomical observation.At present 24 steady basis pillars for measurement whose position coordinates are already known, have been built in the construction field of FAST. Total stations will be installed on one of those pillars, and prisms will be installed on focus cabin. The purpose of this study was to assess the accuracy and reliability of two measuring method: the space distance intersection calculation method and polar measuring method. The space distance intersection calculation method is only using multiple measuring distances between three pillars and prism and known coordinates of pillars to calculate the prism’s coordinates, the polar measurement is using the measuring distance and angles to get the prism’s coordinate.

  1. The Impact of Standardized Acuity Assessment and a Fast-Track on Length of Stay in Obstetric Triage: A Quality Improvement Study.

    PubMed

    Smithson, David S; Twohey, Rachel; Watts, Nancy; Gratton, Robert J

    To prospectively assess the impact of a standardized 5-category Obstetrical Triage Acuity Scale (OTAS) and a fast-track for lower-acuity patients on patient flow. Length of stay (LOS) data of women presenting to obstetric triage were abstracted from the electronic medical record prior to (July 1, 2011, to March 30, 2012) and following OTAS implementation (April 1 to December 31, 2012). Following computerized simulation modeling, a fast-track for lower acuity women was implemented (January 1, 2013, to February 28, 2014). Prior to OTAS implementation (8085 visits), the median LOS was 105 (interquartile range [IQR] = 52-178) minutes. Following OTAS implementation (8131 visits), the median LOS decreased to 101 (IQR = 49-175) minutes (P = .04). The LOS did not correlate well with acuity. Simulation modeling predicted that a fast-track for OTAS 4 and 5 patients would reduce the LOS. The LOS for lower-acuity patients in the fast-track decreased to 73 (IQR = 40-140) minutes (P = .005). In addition, the overall LOS (12 576 visits) decreased to 98 (IQR = 47-172) minutes (6.9% reduction; P < .001). Standardized assessment of acuity and a fast-track for lower acuity pregnant women decreased the overall LOS and the LOS of lower-acuity patients.

  2. Fast Track Teacher Education: A Review of the Research Literature on "Teach For All" Schemes

    ERIC Educational Resources Information Center

    McConney, Andrew; Price, Anne; Woods-McConney, Amanda

    2012-01-01

    This review of the research literature was commissioned by the New Zealand Post-Primary Teachers Association (PPTA) Te Wehengarua as a means of informing the decision-making of the Association and its members about the Teach For All (TFA) scheme seeking to prepare teachers for New Zealand's schools. The systematic review is about fast track…

  3. Faraday-effect polarimeter diagnostic for internal magnetic field fluctuation measurements in DIII-D

    NASA Astrophysics Data System (ADS)

    Chen, J.; Ding, W. X.; Brower, D. L.; Finkenthal, D.; Muscatello, C.; Taussig, D.; Boivin, R.

    2016-11-01

    Motivated by the need to measure fast equilibrium temporal dynamics, non-axisymmetric structures, and core magnetic fluctuations (coherent and broadband), a three-chord Faraday-effect polarimeter-interferometer system with fast time response and high phase resolution has recently been installed on the DIII-D tokamak. A novel detection scheme utilizing two probe beams and two detectors for each chord results in reduced phase noise and increased time response [δb ˜ 1G with up to 3 MHz bandwidth]. First measurement results were obtained during the recent DIII-D experimental campaign. Simultaneous Faraday and density measurements have been successfully demonstrated and high-frequency, up to 100 kHz, Faraday-effect perturbations have been observed. Preliminary comparisons with EFIT are used to validate diagnostic performance. Principle of the diagnostic and first experimental results is presented.

  4. Faraday-effect polarimeter diagnostic for internal magnetic field fluctuation measurements in DIII-D.

    PubMed

    Chen, J; Ding, W X; Brower, D L; Finkenthal, D; Muscatello, C; Taussig, D; Boivin, R

    2016-11-01

    Motivated by the need to measure fast equilibrium temporal dynamics, non-axisymmetric structures, and core magnetic fluctuations (coherent and broadband), a three-chord Faraday-effect polarimeter-interferometer system with fast time response and high phase resolution has recently been installed on the DIII-D tokamak. A novel detection scheme utilizing two probe beams and two detectors for each chord results in reduced phase noise and increased time response [δb ∼ 1G with up to 3 MHz bandwidth]. First measurement results were obtained during the recent DIII-D experimental campaign. Simultaneous Faraday and density measurements have been successfully demonstrated and high-frequency, up to 100 kHz, Faraday-effect perturbations have been observed. Preliminary comparisons with EFIT are used to validate diagnostic performance. Principle of the diagnostic and first experimental results is presented.

  5. Extreme events in Faraday waves

    NASA Astrophysics Data System (ADS)

    Punzmann, Horst; Shats, Michael; Xia, Hua

    2014-05-01

    Observations of extreme wave events in the ocean are rare due to their low statistical probability. In the laboratory however, the evolution of extreme wave events can be studied in great detail with high spatial and temporal resolution. The reported surface wave experiments in the short wavelength gravity-capillary range aim to contribute to the understanding of some of the underlying mechanisms for rogue wave generation. In this talk, we report on extreme wave events in parametrically excited Faraday waves. Faraday waves appear if a fluid is accelerated (normal to the fluid surface) above a critical threshold. A variety of novel tools have been deployed to characterize the 2D surface elevation. The results presented show spatio-temporal and statistical data on the surface wave conditions leading up to extreme wave events. The peak in wave amplitude during such an event is shown to exceed six times the standard deviation of the average wave field with significantly increased statistical probability compared to the background wave field [1]. The experiments also show that parametrically excited waves can be viewed as assembles of oscillons [2] (or oscillating solitons) where modulation instability seems to play a crucial role in their formation. More detailed studies on the oscillon dynamics reveal that the onset of an increased probability of extreme wave events correlates with the increase in the oscillons mobility and merger [3]. Reference: 1. Xia H., Maimbourg T., Punzmann H., and Shats M., Oscillon dynamics and rogue wave generation in Faraday surface ripples, Physical Review Letters 109, 114502 (2012) 2. Shats M., Xia H., and Punzmann H., Parametrically excited water surface ripples as ensembles of oscillons, Physical Review Letters 108, 034502 (2012) 3. Shats M., Punzmann H., Xia H., Capillary rogue waves, Physical Review Letters, 104, 104503 (2010)

  6. Faraday anomalous dispersion optical filters

    NASA Technical Reports Server (NTRS)

    Shay, T. M.; Yin, B.

    1992-01-01

    The present calculations of the performance of Faraday anomalous dispersion optical filters (FADOF) on IR transitions indicate that such filters may furnish high transmission, narrow-pass bandwidth, and low equivalent noise bandwidth under optimum operating conditions. A FADOF consists of an atomic vapor cell between crossed polarizers that are subject to a dc magnetic field along the optical path; when linearly polarized light travels along the direction of the magnetic field through the dispersive atomic vapor, a polarization rotation occurs. If FADOF conditions are suitably adjusted, a maximum transmission with very narrow bandwidth is obtained.

  7. Faraday and the Philosophical Magazine

    NASA Astrophysics Data System (ADS)

    Weinberger, P.

    2013-05-01

    Faraday is considered to be one of the greatest scientists of all time. He not only was a meticulous experimentalist, a true experimental wizard, but also a very prolific author. The many important contributions (almost 50) that he published in the Philosophical Magazine make it highly desirable to catalogue his various inventions, 'discoveries' in his own words, in a scientific language so characteristic of the nineteenth century. It is the purpose of this commentary to guide the reader through his achievements in electrochemistry, magnetism, electric and electromagnetic induction, even 'industrial' applications; to enable him to address a present day audience by means of his contributions to the Philosophical Magazine.

  8. Michael Faraday's work on optical glass

    NASA Astrophysics Data System (ADS)

    James, Frank A. J. L.

    1991-09-01

    This article discusses Faraday's work of the late 1820s to improve optical glass for the joint Royal Society/Board of Longitude Committee set up for this purpose. It points out the importance of this work for some of Faraday's later physical researches.

  9. Soliton mode locking by nonlinear Faraday rotation

    SciTech Connect

    Wabnitz, S.; Westin, E.; Frey, R.; Flytzanis, C.

    1996-11-01

    We propose nonlinear Faraday rotation as a mechanism for achieving stable polarization mode locking of a soliton laser. We analyze by perturbation theory and beam-propagation simulations the interplay between bandwidth-limited gain, gain dichroism, and linear and nonlinear Faraday rotation. {copyright} {ital 1996 Optical Society of America.}

  10. Active imaging system with Faraday filter

    DOEpatents

    Snyder, James J.

    1993-01-01

    An active imaging system has a low to medium powered laser transmitter and receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination while eliminating solar background.

  11. Active imaging system with Faraday filter

    DOEpatents

    Snyder, J.J.

    1993-04-13

    An active imaging system has a low to medium powered laser transmitter and receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination while eliminating solar background.

  12. Lines of Force: Faraday's and Students' Views.

    ERIC Educational Resources Information Center

    Pocovi, M. Cecilia; Finley, Fred

    2002-01-01

    Analyzes how electric and magnetic lines of force were conceived by Faraday and how they are understood by a group of Argentine university students after receiving instruction. Results show that many students possess ideas similar to those of Faraday in that lines of force are conceived as real physical entities responsible for the transmission of…

  13. Faraday current sensor with temperature monitoring

    NASA Astrophysics Data System (ADS)

    Perciante, César D.; Ferrari, José A.

    2005-11-01

    We present a novel optical current sensor based on the Faraday effect that incorporates a temperature monitoring system. The monitoring element is a temperature-dependent birefringent plate placed at the Faraday sensor head. Measurement of the plate retardation permits compensation for the temperature dependence of the Verdet constant. Validation experiments are presented and discussed.

  14. A Comparative Study of Postoperative Pulmonary Complications Using Fast Track Regimen and Conservative Analgesic Treatment: A Randomized Clinical Trial

    PubMed Central

    Aghdam, Babak Abri; Golzari, Samad Eslam Jamal; Moghadaszadeh, Majid

    2011-01-01

    Background Postoperative pulmonary complications and pain are important causes of postoperative morbidity following thoracotomy. This study aimed to compare the effects of fast track and conservative treatment regimens on patients undergoing thoracotomy. Materials and Methods In this randomized controlled clinical trial, we recruited 60 patients admitted to the thoracic ICU of Imam Reza Hospital in two matched groups of 30 patients each. Group 1 patients received fast track regimen randomly; whereas, group 2 cases randomly received conservative analgesic regimen after thoracotomy and pulmonary resection. The outcome was determined based on the incidence of pulmonary complications and reduction of post-thoracotomy pain in all patients with forced expiratory volume in one second (FEV1) <75% predicted value which was measured while the patients were in ICU. The length of ICU stay, thoracotomy pain, morbidity, pulmonary complications and mortality were compared in two groups. Results A total of 60 patients, 45 (75%) males and 15(25%) females with ASA class I-III were recruited in this study. Postoperative pulmonary complications were observed in 5 (16.7%) patients in group 1 versus 17 (56.7%) patients in group 2. There were statistically significant differences in development of postoperative pulmonary complications such as atelectasis and prolonged air leak between both groups (P< 0.001 and P = 0.003). There was also a statistically significant difference in the rate of preoperative FEV1 (p = 0.001) and ASA scoring (p = 0.01) and value of FEV1 < 75% predicted in the two groups. The difference in length of ICU stay in two groups was statistically significant (P= 0.003 and P = 0.017 in FEV1 < 75% group). Four patients in group 1 and 9 patients in group 2 had FEV1reduced to less than 75% of predicted value (p = 0.03). Conclusion Using fast track regimen reduced postoperative pain and incidence of some pulmonary complications significantly when compared to the

  15. Fast leaf-fitting with generalized underdose/overdose constraints for real-time MLC tracking

    SciTech Connect

    Moore, Douglas Sawant, Amit; Ruan, Dan

    2016-01-15

    Purpose: Real-time multileaf collimator (MLC) tracking is a promising approach to the management of intrafractional tumor motion during thoracic and abdominal radiotherapy. MLC tracking is typically performed in two steps: transforming a planned MLC aperture in response to patient motion and refitting the leaves to the newly generated aperture. One of the challenges of this approach is the inability to faithfully reproduce the desired motion-adapted aperture. This work presents an optimization-based framework with which to solve this leaf-fitting problem in real-time. Methods: This optimization framework is designed to facilitate the determination of leaf positions in real-time while accounting for the trade-off between coverage of the PTV and avoidance of organs at risk (OARs). Derived within this framework, an algorithm is presented that can account for general linear transformations of the planned MLC aperture, particularly 3D translations and in-plane rotations. This algorithm, together with algorithms presented in Sawant et al. [“Management of three-dimensional intrafraction motion through real-time DMLC tracking,” Med. Phys. 35, 2050–2061 (2008)] and Ruan and Keall [Presented at the 2011 IEEE Power Engineering and Automation Conference (PEAM) (2011) (unpublished)], was applied to apertures derived from eight lung intensity modulated radiotherapy plans subjected to six-degree-of-freedom motion traces acquired from lung cancer patients using the kilovoltage intrafraction monitoring system developed at the University of Sydney. A quality-of-fit metric was defined, and each algorithm was evaluated in terms of quality-of-fit and computation time. Results: This algorithm is shown to perform leaf-fittings of apertures, each with 80 leaf pairs, in 0.226 ms on average as compared to 0.082 and 64.2 ms for the algorithms of Sawant et al., Ruan, and Keall, respectively. The algorithm shows approximately 12% improvement in quality-of-fit over the Sawant et al

  16. A prospective study to assess the implementation of a fast-track system to meet the two-week target for colorectal cancer in Somerset.

    PubMed

    Davies, R. J.; Ewings, P.; Welbourn, R.; Collins, C.; Kennedy, R.; Royle, C.

    2002-01-01

    OBJECTIVE: This prospective study assesses the introduction of a fast-track referral system for patients with suspected colorectal cancer. PATIENTS AND METHODS: The referral system was initiated in Yeovil District Hospital and Taunton and Somerset Hospital using six screening criteria to select high-risk patients. Data on all high-risk patients from 1 November 1999 to 30 April 2000 was recorded prospectively. Patients with proven colorectal cancer diagnosed between 1 November 1998 and 30 April 1999 have been identified for comparison. RESULTS: There were 158 new cases of colorectal cancer in total (111 elective, 47 emergency). 59 cases of colorectal cancer were diagnosed from 433 fast-track referrals (53% of total elective cases). Median time from referral to diagnosis in the fast-track group was 11 days vs. 32.5 days for nonfast-track elective patients (P < 0.001). Median time from referral to diagnosis for all elective cases was 17 days vs. 38.5 days for patients presenting one year earlier (P < 0.001). 75% of fast-track patients were diagnosed with colorectal cancer within two weeks, compared with 17% of nonfast-track elective patients (P < 0.001). The proportion of emergency admissions was reduced from 40% to 30% (P=0.07) following the introduction of this system. CONCLUSION: Data from the first six months reveal that over half of the elective cases of colorectal cancer were diagnosed within the fast-track system. The median time from referral to diagnosis in these patients was within two weeks and there has been a significant reduction in the time to diagnosis associated with the introduction of this service.

  17. Indirect Effects of the Fast Track Intervention on Conduct Disorder Symptoms and Callous-Unemotional Traits: Distinct Pathways Involving Discipline and Warmth

    PubMed Central

    Pasalich, Dave S.; Witkiewitz, Katie; McMahon, Robert J.; Pinderhughes, Ellen E.

    2016-01-01

    Little is known about intervening processes that explain how prevention programs improve particular youth antisocial outcomes. We examined whether parental harsh discipline and warmth in childhood differentially account for Fast Track intervention effects on conduct disorder (CD) symptoms and callous-unemotional (CU) traits in early adolescence. Participants included 891 high-risk kindergarteners (69% male; 51% African American) from urban and rural United States communities who were randomized into either the Fast Track intervention (n = 445) or non-intervention control (n = 446) groups. The 10-year intervention included parent management training and other services (e.g., social skills training, universal classroom curriculum) targeting various risk factors for the development of conduct problems. Harsh discipline (Grades 1 through 3) and warmth (Grades 1 and 2) were measured using parent responses to vignettes and direct observations of parent-child interaction, respectively. Parents reported on children’s CD symptoms in Grade 6 and CU traits in Grade 7. Results demonstrated indirect effects of the Fast Track intervention on reducing risk for youth antisocial outcomes. That is, Fast Track was associated with lower scores on harsh discipline, which in turn predicted decreased levels of CD symptoms. In addition, Fast Track was associated with higher scores on warmth, which in turn predicted reduced levels of CU traits. Our findings inform developmental and intervention models of youth antisocial behavior by providing evidence for the differential role of harsh discipline and warmth in accounting for indirect effects of Fast Track on CD symptoms versus CU traits, respectively. PMID:26242993

  18. Indirect Effects of the Fast Track Intervention on Conduct Disorder Symptoms and Callous-Unemotional Traits: Distinct Pathways Involving Discipline and Warmth.

    PubMed

    Pasalich, Dave S; Witkiewitz, Katie; McMahon, Robert J; Pinderhughes, Ellen E

    2016-04-01

    Little is known about intervening processes that explain how prevention programs improve particular youth antisocial outcomes. We examined whether parental harsh discipline and warmth in childhood differentially account for Fast Track intervention effects on conduct disorder (CD) symptoms and callous-unemotional (CU) traits in early adolescence. Participants included 891 high-risk kindergarteners (69% male; 51% African American) from urban and rural United States communities who were randomized into either the Fast Track intervention (n = 445) or non-intervention control (n = 446) groups. The 10-year intervention included parent management training and other services (e.g., social skills training, universal classroom curriculum) targeting various risk factors for the development of conduct problems. Harsh discipline (Grades 1 to 3) and warmth (Grades 1 and 2) were measured using parent responses to vignettes and direct observations of parent-child interaction, respectively. Parents reported on children's CD symptoms in Grade 6 and CU traits in Grade 7. Results demonstrated indirect effects of the Fast Track intervention on reducing risk for youth antisocial outcomes. That is, Fast Track was associated with lower scores on harsh discipline, which in turn predicted decreased levels of CD symptoms. In addition, Fast Track was associated with higher scores on warmth, which in turn predicted reduced levels of CU traits. Our findings inform developmental and intervention models of youth antisocial behavior by providing evidence for the differential role of harsh discipline and warmth in accounting for indirect effects of Fast Track on CD symptoms versus CU traits, respectively.

  19. Faraday diagnostics for ALT-3

    SciTech Connect

    Oro, David M; Tabaka, Leonard J

    2011-01-13

    ALT-3 and R-Damage are experiments to be executed in collaboration between LANL and VNIIEF personnel. They are planned to be fielded in Sarov, Russia at VNIIEF. Both experiments employ Russian explosively driven pulse-power systems to generate a pulse of electrical current that is used to drive the experiment. The current pulse will be measured with Faraday-rotation fiber-optic loops. Using this well known technique, the change in the current enclosed by the loops is determined by measuring the change in the magnetic field integrated along the fiber-optic loop by detecting the Faraday rotation of linearly polarized light traveling through the fiber. The amount of polarization rotation of the light is related to the integrated magnetic field and therefore the enclosed current (Ampere's law) through the Verdet constant which for the optical-fibers used in this experiment has been determined to within 1 %. The presentation describes how the technique will be employed in the ALT-3 experiment.

  20. The impact of a fast track area on quality and effectiveness outcomes: A Middle Eastern emergency department perspective

    PubMed Central

    Devkaran, Subashnie; Parsons, Howard; Van Dyke, Murray; Drennan, Jonathan; Rajah, Jaishen

    2009-01-01

    Background Emergency department (ED) overcrowding is a ubiquitous problem with serious public health implications. The fast track area is a novel method which aims to reduce waiting time, patient dissatisfaction and morbidity. |The study objective was to determine the impact of a fast track area (FTA) on both effectiveness measures (i.e. waiting times [WT] and length of stay [LOS]) and quality measures (i.e. LWBS rates and mortality rates) in non-urgent patients. The secondary objective was to assess if a FTA negatively impacted on urgent patients entering the ED. Methods The study took place in a 500 bed, urban, tertiary care hospital in Abu Dhabi, United Arab Emirates. This was a quasi-experimental, which examined the impact of a FTA on a pre-intervention control group (January 2005) (n = 4,779) versus a post-intervention study group (January 2006) (n = 5,706). Results Mean WTs of Canadian Triage Acuity Scale (CTAS) 4 patients decreased by 22 min (95% CI 21 min to 24 min, P < 0.001). Similarly, mean WTs of CTAS 5 patients decreased by 28 min (95% CI 19 min to 37 min, P < 0.001) post FTA. The mean WTs of urgent patients (CTAS 2/3) were also significantly reduced after the FTA was opened (P < 0.001). The LWBS rate was reduced from 4.7% to 0.7% (95% CI 3.37 to 4.64; P < 0.001). Opening a FTA had no significant impact on mortality rates (P = 0.88). Conclusion The FTA improved ED effectiveness (WTs and LOS) and quality measures (LWBS rates) whereas mortality rate remained unchanged. PMID:19534787

  1. Which patient characteristics influence length of hospital stay after primary total hip arthroplasty in a 'fast-track' setting?

    PubMed

    den Hartog, Y M; Mathijssen, N M C; Hannink, G; Vehmeijer, S B W

    2015-01-01

    After implementation of a 'fast-track' rehabilitation protocol in our hospital, mean length of hospital stay for primary total hip arthroplasty decreased from 4.6 to 2.9 nights for unselected patients. However, despite this reduction there was still a wide range across the patients' hospital duration. The purpose of this study was to identify which specific patient characteristics influence length of stay after successful implementation of a 'fast-track' rehabilitation protocol. A total of 477 patients (317 female and 160 male, mean age 71.0 years; 39.3 to 92.6, mean BMI 27.0 kg/m(2);18.8 to 45.2) who underwent primary total hip arthroplasty between 1 February 2011 and 31 January 2013, were included in this retrospective cohort study. A length of stay greater than the median was considered as an increased duration. Logistic regression analyses were performed to identify potential factors associated with increased durations. Median length of stay was two nights (interquartile range 1), and the mean length of stay 2.9 nights (1 to 75). In all, 266 patients had a length of stay ≤ two nights. Age (odds ratio (OR) 2.46; 95% confidence intervals (CI) 1.72 to 3.51; p < 0.001), living situation (alone vs living together with cohabitants, OR 2.09; 95% CI 1.33 to 3.30; p = 0.002) and approach (anterior approach vs lateral, OR 0.29; 95% CI 0.19 to 0.46; p < 0.001) (posterolateral approach vs lateral, OR 0.24; 95% CI 0.10 to 0.55; p < 0.001) were factors that were significantly associated with increased length of stay in the multivariable logistic regression model.

  2. Evaluation of the influence of pulmonary hypertension in ultra-fast-track anesthesia technique in adult patients undergoing cardiac surgery

    PubMed Central

    da Silva, Paulo Sérgio; Cartacho, Márcio Portugal Trindade; de Castro, Casimiro Cardoso; Salgado Filho, Marcello Fonseca; Brandão, Antônio Carlos Aguiar

    2015-01-01

    Objective To evaluate the influence of pulmonary hypertension in the ultra-fast-track anesthesia technique in adult cardiac surgery. Methods A retrospective study. They were included 40 patients divided into two groups: GI (without pulmonary hypertension) and GII (with pulmonary hypertension). Based on data obtained by transthoracic echocardiography. We considered as the absence of pulmonary hypertension: a pulmonary artery systolic pressure (sPAP) <36 mmHg, with tricuspid regurgitation velocity <2.8 m/s and no additional echocardiographic signs of PH, and PH as presence: a sPAP >40 mmHg associated with additional echocardiographic signs of PH. It was established as influence of pulmonary hypertension: the impossibility of extubation in the operating room, the increase in the time interval for extubation and reintubation the first 24 hours postoperatively. Univariate and multivariate analyzes were performed when necessary. Considered significant a P value <0.05. Results The GI was composed of 21 patients and GII for 19. All patients (100%) were extubated in the operating room in a medium time interval of 17.58±8.06 min with a median of 18 min in GII and 17 min in GI. PH did not increase the time interval for extubation (P=0.397). It required reintubation of 2 patients in GII (5% of the total), without statistically significant as compared to GI (P=0.488). Conclusion In this study, pulmonary hypertension did not influence on ultra-fast-track anesthesia in adult cardiac surgery. PMID:27163419

  3. A fast-initializing digital equalizer with on-line tracking for data communications

    NASA Technical Reports Server (NTRS)

    Houts, R. C.; Barksdale, W. J.

    1974-01-01

    A theory is developed for a digital equalizer for use in reducing intersymbol interference (ISI) on high speed data communications channels. The equalizer is initialized with a single isolated transmitter pulse, provided the signal-to-noise ratio (SNR) is not unusually low, then switches to a decision directed, on-line mode of operation that allows tracking of channel variations. Conditions for optimal tap-gain settings are obtained first for a transversal equalizer structure by using a mean squared error (MSE) criterion, a first order gradient algorithm to determine the adjustable equalizer tap-gains, and a sequence of isolated initializing pulses. Since the rate of tap-gain convergence depends on the eigenvalues of a channel output correlation matrix, convergence can be improved by making a linear transformation on to obtain a new correlation matrix.

  4. Predictive filtering-based fast reacquisition approach for space-borne acquisition, tracking, and pointing systems.

    PubMed

    Bai, Shuai; Wang, Jianyu; Qiang, Jia; Zhang, Liang; Wang, Juanjuan

    2014-11-03

    We propose a novel approach for recapturing targets as quickly as possible after the space-borne ATP (Acquisition, Tracking, and Pointing) system target loss in free-space laser communication. The approach uses past angular information to predict the target trajectory. An optimized finite memory filter is designed as the prediction algorithm. To obtain optimal prediction performance, the designed filter determines the filter parameters of different curve parts during offline training, and the parameters are adjusted according to the curve characteristics during predictive filtering. Simulation results indicate prediction accuracy above 0.1 degrees within 5 seconds. An experimental system was constructed in the lab to simulate the reacquisition process using a dynamic target and a real ATP system. Experimental results show that, compared with the classical orbit prediction method, this approach can effectively yield shorter acquisition times.

  5. Adaptive AFM scan speed control for high aspect ratio fast structure tracking

    SciTech Connect

    Ahmad, Ahmad; Schuh, Andreas; Rangelow, Ivo W.

    2014-10-15

    Improved imaging rates in Atomic Force Microscopes (AFM) are of high interest for disciplines such as life sciences and failure analysis of semiconductor wafers, where the sample topology shows high aspect ratios. Also, fast imaging is necessary to cover a large surface under investigation in reasonable times. Since AFMs are composed of mechanical components, they are associated with comparably low resonance frequencies that undermine the effort to increase the acquisition rates. In particular, high and steep structures are difficult to follow, which causes the cantilever to temporarily loose contact to or crash into the sample. Here, we report on a novel approach that does not affect the scanner dynamics, but adapts the lateral scanning speed of the scanner. The controller monitors the control error signal and, only when necessary, decreases the scan speed to allow the z-piezo more time to react to changes in the sample's topography. In this case, the overall imaging rate can be significantly increased, because a general scan speed trade-off decision is not needed and smooth areas are scanned fast. In contrast to methods trying to increase the z-piezo bandwidth, our method is a comparably simple approach that can be easily adapted to standard systems.

  6. Fast noninvasive eye-tracking and eye-gaze determination for biomedical and remote monitoring applications

    NASA Astrophysics Data System (ADS)

    Talukder, Ashit; Morookian, John M.; Monacos, Steve P.; Lam, Raymond K.; Lebaw, C.; Bond, A.

    2004-04-01

    Eyetracking is one of the latest technologies that has shown potential in several areas including human-computer interaction for people with and without disabilities, and for noninvasive monitoring, detection, and even diagnosis of physiological and neurological problems in individuals. Current non-invasive eyetracking methods achieve a 30 Hz rate with possibly low accuracy in gaze estimation, that is insufficient for many applications. We propose a new non-invasive visual eyetracking system that is capable of operating at speeds as high as 6-12 KHz. A new CCD video camera and hardware architecture is used, and a novel fast image processing algorithm leverages specific features of the input CCD camera to yield a real-time eyetracking system. A field programmable gate array (FPGA) is used to control the CCD camera and execute the image processing operations. Initial results show the excellent performance of our system under severe head motion and low contrast conditions.

  7. FAST TRACK COMMUNICATION: Plasma agents in bio-decontamination by dc discharges in atmospheric air

    NASA Astrophysics Data System (ADS)

    Machala, Zdenko; Chládeková, Lenka; Pelach, Michal

    2010-06-01

    Bio-decontamination of water and surfaces contaminated by bacteria (Salmonella typhimurium) was investigated in two types of positive dc discharges in atmospheric pressure air, in needle-to-plane geometry: the streamer corona and its transition to a novel regime called transient spark with short high current pulses of limited energy. Both generate a cold non-equilibrium plasma. Electro-spraying of treated water through a needle electrode was applied for the first time and resulted in fast bio-decontamination. Experiments providing separation of various biocidal plasma agents, along with the emission spectra and coupled with oxidation stress measurements in the cell membranes helped to better understand the mechanisms of microbial inactivation. The indirect exposure of contaminated surfaces to neutral active species was almost as efficient as the direct exposure to the plasma, whereas applying only UV radiation from the plasma had no biocidal effects. Radicals and reactive oxygen species were identified as dominant biocidal agents.

  8. Open LED Illuminator: A Simple and Inexpensive LED Illuminator for Fast Multicolor Particle Tracking in Neurons

    PubMed Central

    Bosse, Jens B.; Tanneti, Nikhila S.; Hogue, Ian B.; Enquist, Lynn W.

    2015-01-01

    Dual-color live cell fluorescence microscopy of fast intracellular trafficking processes, such as axonal transport, requires rapid switching of illumination channels. Typical broad-spectrum sources necessitate the use of mechanical filter switching, which introduces delays between acquisition of different fluorescence channels, impeding the interpretation and quantification of highly dynamic processes. Light Emitting Diodes (LEDs), however, allow modulation of excitation light in microseconds. Here we provide a step-by-step protocol to enable any scientist to build a research-grade LED illuminator for live cell microscopy, even without prior experience with electronics or optics. We quantify and compare components, discuss our design considerations, and demonstrate the performance of our LED illuminator by imaging axonal transport of herpes virus particles with high temporal resolution. PMID:26600461

  9. Faraday wave lattice as an elastic metamaterial.

    PubMed

    Domino, L; Tarpin, M; Patinet, S; Eddi, A

    2016-05-01

    Metamaterials enable the emergence of novel physical properties due to the existence of an underlying subwavelength structure. Here, we use the Faraday instability to shape the fluid-air interface with a regular pattern. This pattern undergoes an oscillating secondary instability and exhibits spontaneous vibrations that are analogous to transverse elastic waves. By locally forcing these waves, we fully characterize their dispersion relation and show that a Faraday pattern presents an effective shear elasticity. We propose a physical mechanism combining surface tension with the Faraday structured interface that quantitatively predicts the elastic wave phase speed, revealing that the liquid interface behaves as an elastic metamaterial.

  10. Faraday rotation system. Topical report

    SciTech Connect

    Bauman, L.E.; Wang, W.

    1994-07-01

    The Faraday Rotation System (FRS) is one of the advanced laser-based diagnostics developed at DIAL to provide support for the demonstration of prototype-scale coal-fired combustion magnetohydrodynamic (MHD) electrical power generation. Intended for application in the MHD channel, the system directly measures electron density through a measurement of the induced rotation in the polarization of a far infrared laser beam after passing through the MHD flow along the magnetic field lines. A measurement of the induced polarization ellipticity provides a measure of the electron collision frequency which together with the electron density gives the electron conductivity, a crucial parameter for MHD channel performance. The theory of the measurements, a description of the system, its capabilities, laboratory demonstration measurements on seeded flames with comparison to emission absorption measurements, and the current status of the system are presented in this final report.

  11. Faraday instability in deformable domains

    NASA Astrophysics Data System (ADS)

    Pucci, Giuseppe; Ben Amar, Martine; Couder, Yves

    2014-11-01

    We investigate the Faraday instability in floating liquid lenses, as an example of hydrodynamic instability that develops in a domain with flexible boundaries. We show that a mutual adaptation of the instability pattern and the domain shape occurs, as a result of the competition between the wave radiation pressure and the capillary response of the lens border. Two archetypes of behaviour are observed. In the first, stable shapes are obtained experimentally and predicted theoretically as the exact solutions of a Riccati equation, and they result from the equilibrium between wave radiation pressure and capillarity. In the second, the radiation pressure exceeds the capillary response of the lens border and leads to non-equilibrium behaviours, with breaking into smaller domains that have a complex dynamics including spontaneous propagation. The authors are grateful to Université Franco-Italienne (UFI) for financial support.

  12. Theory of nanotube faraday cage

    NASA Astrophysics Data System (ADS)

    Roxana Margine, Elena; Nisoli, Cristiano; Kolmogorov, Aleksey; Crespi, Vincent H.

    2003-03-01

    Charge transfer between dopants and double-wall carbon nanotubes is examined theoretically. We model the system as a triple cylindrical capacitor with the dopants forming a shell around the outer wall of the nanotube. The total energy of the system contains three terms: the band structure energies of the inner and outer tube, calculated in a tight-binding model with rigid bands, and the electrostatic energy of the tri-layer distribution. Even for metallic inner and outer tube walls, wherein the diameter dependence of the bandgap does not favor the outer wall, nearly all of the dopant charge resides on the outer layer, a nanometer-scale Faraday cage. The calculated charge distribution is in agreement with recent experimental measurements.

  13. Scientists raise alarms about fast tracking of transoceanic canal through Nicaragua.

    PubMed

    Huete-Pérez, Jorge A; Alvarez, Pedro J J; Schnoor, Jerald L; Rittmann, Bruce E; Clayton, Anthony; Acosta, Maria L; Bicudo, Carlos E M; K Arroyo, Mary T; Brett, Michael T; Campos, Victor M; Chaimovich, Hernan; Jimenez-Cisneros, Blanca; Covich, Alan; Lacerda, Luiz D; Maes, Jean-Michel; Miranda, Julio C; Montenegro-Guillén, Salvador; Ortega-Hegg, Manuel; Urquhart, Gerald R; Vammen, Katherine; Zambrano, Luis

    2015-04-07

    Seeking economic growth and job creation to tackle the nation's extreme poverty, the Nicaraguan government awarded a concession to build an interoceanic canal and associated projects to a recently formed Hong Kong based company with no track record or related expertise. This concession was awarded without a bidding process and in advance of any feasibility, socio-economic or environmental impact assessments; construction has begun without this information. The 278 km long interoceanic canal project may result in significant environmental and social impairments. Of particular concern are damage to Lake Cocibolca, a unique freshwater tropical lake and Central America's main freshwater reservoir; damage to regional biodiversity and ecosystems; and socio-economic impacts. Concerned about the possibly irreparable damage to the environment and to native communities, conservationists and the scientific community at large are urging the Nicaraguan government to devise and reveal an action plan to address and mitigate the possible negative repercussions of this interoceanic canal and associated projects. Critical research needs for preparation of a comprehensive benefit-cost analysis for this megaproject are presented.

  14. 76 FR 6369 - Changes To Implement the Prioritized Examination Track (Track I) of the Enhanced Examination...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-04

    ... implementation of the Prioritized Examination Track (Track I), providing fast examination for applicants desiring... examiners or supervisory patent examiners, specialized examiner training for fast track...

  15. Expanding Support for Education in Fragile States: What Role for the Education for All-Fast Track Initiative? CREATE Pathways to Access. Research Monograph No. 30

    ERIC Educational Resources Information Center

    Turrent, Victoria

    2009-01-01

    The new international aid architecture was established to improve the efficiency and effectiveness of development aid by emphasising country ownership, alignment with national priorities and the harmonisation of donor processes. These features are evident in the Education for All-Fast Track Initiative [EFA-FTI], a global partnership between donor…

  16. Improvements in fast-response flood modeling: desktop parallel computing and domain tracking

    SciTech Connect

    Judi, David R; Mcpherson, Timothy N; Burian, Steven J

    2009-01-01

    It is becoming increasingly important to have the ability to accurately forecast flooding, as flooding accounts for the most losses due to natural disasters in the world and the United States. Flood inundation modeling has been dominated by one-dimensional approaches. These models are computationally efficient and are considered by many engineers to produce reasonably accurate water surface profiles. However, because the profiles estimated in these models must be superimposed on digital elevation data to create a two-dimensional map, the result may be sensitive to the ability of the elevation data to capture relevant features (e.g. dikes/levees, roads, walls, etc...). Moreover, one-dimensional models do not explicitly represent the complex flow processes present in floodplains and urban environments and because two-dimensional models based on the shallow water equations have significantly greater ability to determine flow velocity and direction, the National Research Council (NRC) has recommended that two-dimensional models be used over one-dimensional models for flood inundation studies. This paper has shown that two-dimensional flood modeling computational time can be greatly reduced through the use of Java multithreading on multi-core computers which effectively provides a means for parallel computing on a desktop computer. In addition, this paper has shown that when desktop parallel computing is coupled with a domain tracking algorithm, significant computation time can be eliminated when computations are completed only on inundated cells. The drastic reduction in computational time shown here enhances the ability of two-dimensional flood inundation models to be used as a near-real time flood forecasting tool, engineering, design tool, or planning tool. Perhaps even of greater significance, the reduction in computation time makes the incorporation of risk and uncertainty/ensemble forecasting more feasible for flood inundation modeling (NRC 2000; Sayers et al

  17. High rate particle tracking and ultra-fast timing with a thin hybrid silicon pixel detector

    NASA Astrophysics Data System (ADS)

    Fiorini, M.; Aglieri Rinella, G.; Carassiti, V.; Ceccucci, A.; Cortina Gil, E.; Cotta Ramusino, A.; Dellacasa, G.; Garbolino, S.; Jarron, P.; Kaplon, J.; Kluge, A.; Marchetto, F.; Mapelli, A.; Martin, E.; Mazza, G.; Morel, M.; Noy, M.; Nuessle, G.; Perktold, L.; Petagna, P.; Petrucci, F.; Poltorak, K.; Riedler, P.; Rivetti, A.; Statera, M.; Velghe, B.

    2013-08-01

    The Gigatracker (GTK) is a hybrid silicon pixel detector designed for the NA62 experiment at CERN. The beam spectrometer, made of three GTK stations, has to sustain high and non-uniform particle rate (∼ 1 GHz in total) and measure momentum and angles of each beam track with a combined time resolution of 150 ps. In order to reduce multiple scattering and hadronic interactions of beam particles, the material budget of a single GTK station has been fixed to 0.5% X0. The expected fluence for 100 days of running is 2 ×1014 1 MeV neq /cm2, comparable to the one foreseen in the inner trackers of LHC detectors during 10 years of operation. To comply with these requirements, an efficient and very low-mass (< 0.15 %X0) cooling system is being constructed, using a novel microchannel cooling silicon plate. Two complementary read-out architectures have been produced as small-scale prototypes: one is based on a Time-over-Threshold circuit followed by a TDC shared by a group of pixels, while the other makes use of a constant-fraction discriminator followed by an on-pixel TDC. The read-out ASICs are produced in 130 nm IBM CMOS technology and will be thinned down to 100 μm or less. An overview of the Gigatracker detector system will be presented. Experimental results from laboratory and beam tests of prototype bump-bonded assemblies will be described as well. These results show a time resolution of about 170 ps for single hits from minimum ionizing particles, using 200 μm thick silicon sensors.

  18. Michael Faraday's Contributions to Archaeological Chemistry.

    PubMed

    Moshenska, Gabriel

    2015-08-01

    The analysis of ancient artefacts is a long but largely neglected thread within the histories of archaeology and chemistry. This paper examines Michael Faraday's contributions to this nascent field, drawing on his published correspondence and the works of his antiquarian collaborators, and focusing in particular on his analyses of Romano-British and ancient Egyptian artefacts. Faraday examined the materials used in ancient Egyptian mummification, and provided the first proof of the use of lead glazes on Roman ceramics. Beginning with an assessment of Faraday's personal interests and early work on antiquities with Humphry Davy, this paper critically examines the historiography of archaeological chemistry and attempts to place Faraday's work within its institutional, intellectual, and economic contexts.

  19. Calibrated Faraday current and magnetic field sensor

    NASA Astrophysics Data System (ADS)

    Neyer, B. T.; Chang, J.; Lockwood, G. J.; Ruggles, L. E.

    A calibrated optical fiber Faraday rotation current sensor is developed. This sensor has a gigahertz response, is immune to electromagnetic interference, and is constructed entirely of dielectric material. All of these advantages make the sensor ideal for pulsed power measurements.

  20. Active imaging system with Faraday filter

    SciTech Connect

    Snyder, J.J.

    1992-12-31

    This invention is comprised of an active imaging system which has a low to medium powered laser transmitter and a receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination wile eliminating solar background.

  1. Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system

    SciTech Connect

    Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc; Binnekamp, Dirk

    2015-03-15

    Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora{sup ®} Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators.

  2. Monitoring Fast-Moving Landslide in the Three Gorges Area By Offset Tracking Method with High-Resolution SAR Data

    NASA Astrophysics Data System (ADS)

    Liao, M.; Shi, X.; Zhang, L.; Balz, T.

    2014-12-01

    Landslide has long been considered as a major geological hazard with great threats to local residents and social economic developments within the Three Gorges area, China. With the regular operation of Three Gorges Dam since 2009, the reservoir water level undergoes an annual cycle from 145 m in early summer to 175 m in early winter caused by storage and discharge operations. Consequently, many ancient landslides were activated by such large variations of water level. One of typical examples is the famous Shuping landslide located in Zigui County. To reduce the risks of landslide collapse, long-term monitoring of ground surface deformation must be carried out. Terrestrial surveillance like GPS and extensometer have been installed at Shuping in 2003. Although these methods can achieve highly accurate displacement measurements, only sparse points can be observed, which is far from the requirement of monitoring vast reservoir area coverage. For such a vast and inaccessible area, D-InSAR and PS-InSAR can measure long-term and continuous displacement trends. Nevertheless, it has been revealed by several studies that InSAR can hardly retrieve accurate deformation signal on fast-moving landslides such as Shuping. Therefore, we further investigated the feasibility and effectiveness of pixel offset tracking (POT) method to detect fast-moving with high-resolution SAR data. One of the key points is to estimate displacement at each pixel through subpixel-level SAR image matching. In order to tackle the difficulties of using traditional POT technique, the point-like target offset tracking (PTOT) is developed. By making use of point-like targets with stable backscattering behavior over long time span, PTOT method is can achieve more reliable results with accuracies at 1/20 of SAR pixel resolution. More importantly, PTOT method can measure two-dimensional displacements, i.e. in both azimuth and slant range direction, while InSAR can measure displacement only along the line

  3. School outcomes of aggressive-disruptive children: prediction from kindergarten risk factors and impact of the fast track prevention program.

    PubMed

    Bierman, Karen L; Coie, John; Dodge, Kenneth; Greenberg, Mark; Lochman, John; McMohan, Robert; Pinderhughes, Ellen

    2013-01-01

    A multi-gate screening process identified 891 children with aggressive-disruptive behavior problems at school entry. Fast Track provided a multi-component preventive intervention in the context of a randomized-controlled design. In addition to psychosocial support and skill training for parents and children, the intervention included intensive reading tutoring in first grade, behavioral management consultation with teachers, and the provision of homework support (as needed) through tenth grade. This study examined the impact of the intervention, as well as the impact of the child's initial aggressive-disruptive behaviors and associated school readiness skills (cognitive ability, reading readiness, attention problems) on academic progress and educational placements during elementary school (Grades 1-4) and during the secondary school years (Grades 7-10), as well as high school graduation. Child behavior problems and skills at school entry predicted school difficulties (low grades, grade retention, placement in a self-contained classroom, behavior disorder classification, and failure to graduate). Disappointingly, intervention did not significantly improve these long-term school outcomes.

  4. Rapid and complete hitless defragmentation method using a coherent RX LO with fast wavelength tracking in elastic optical networks.

    PubMed

    Proietti, Roberto; Qin, Chuan; Guan, Binbin; Yin, Yawei; Scott, Ryan P; Yu, Runxiang; Yoo, S J B

    2012-11-19

    This paper demonstrates a rapid and full hitless defragmentation method in elastic optical networks exploiting a new technique for fast wavelength tracking in coherent receivers. This technique can be applied to a single-carrier connection or each of the subcarriers forming a super-channel. A proof-of-concept demonstration shows hitless defragmentation of a 10 Gb/s QPSK single-carrier connection from 1547.75 nm to 1550.1 nm in less than 1 µs. This was obtained using a small (0.625 kB) link-layer transmitter buffer without the need for any additional transponder. We also demonstrated that the proposed defragmentation technique is capable of hopping over an existing connection, i.e. 10 Gb/s OOK at 1548.5 nm, without causing any degradation of its real-time Bit Error Rate (BER) value. The proposed scheme gives advantages in terms of overall network blocking probability reduction up to a factor of 40.

  5. Single-molecule tracking of tau reveals fast kiss-and-hop interaction with microtubules in living neurons.

    PubMed

    Janning, Dennis; Igaev, Maxim; Sündermann, Frederik; Brühmann, Jörg; Beutel, Oliver; Heinisch, Jürgen J; Bakota, Lidia; Piehler, Jacob; Junge, Wolfgang; Brandt, Roland

    2014-11-05

    The microtubule-associated phosphoprotein tau regulates microtubule dynamics and is involved in neurodegenerative diseases collectively called tauopathies. It is generally believed that the vast majority of tau molecules decorate axonal microtubules, thereby stabilizing them. However, it is an open question how tau can regulate microtubule dynamics without impeding microtubule-dependent transport and how tau is also available for interactions other than those with microtubules. Here we address this apparent paradox by fast single-molecule tracking of tau in living neurons and Monte Carlo simulations of tau dynamics. We find that tau dwells on a single microtubule for an unexpectedly short time of ∼40 ms before it hops to the next. This dwell time is 100-fold shorter than previously reported by ensemble measurements. Furthermore, we observed by quantitative imaging using fluorescence decay after photoactivation recordings of photoactivatable GFP-tagged tubulin that, despite this rapid dynamics, tau is capable of regulating the tubulin-microtubule balance. This indicates that tau's dwell time on microtubules is sufficiently long to influence the lifetime of a tubulin subunit in a GTP cap. Our data imply a novel kiss-and-hop mechanism by which tau promotes neuronal microtubule assembly. The rapid kiss-and-hop interaction explains why tau, although binding to microtubules, does not interfere with axonal transport.

  6. First results of Faraday-effect polarimeter measurements of internal magnetic fluctuation in DIII-D

    NASA Astrophysics Data System (ADS)

    Chen, J.; Ding, W. X.; Brower, D. L.

    2016-10-01

    Motivated by the need to measure fast equilibrium temporal dynamics, non-axisymmetric structures and core magnetic fluctuations (coherent and broadband), a 694 GHz Faraday-effect polarimeter has recently been installed on the DIII-D tokamak. A novel detection scheme is utilized, which results in simultaneous integral density measurement, to isolate the magnetic component, along with fast time response (up to 3MHz) and high phase resolution (1 ×10-4 degree2/kHz, equivalent to <1 Gauss at medium to high electron density conditions). Spatial resolution is provided by three radial chords located at z = 0 cm and z = +/- 13.5 cm (z = 0 cm is machine center). Simultaneous Faraday rotation and integral density measurements have been demonstrated in the experimental campaign of 2016, with good agreement with MSE-constrained EFIT. The change of Faraday rotation during sawteeth indicates periodic evolution of current density in the core plasma. Coherent and broadband fluctuations associated with plasma instabilities and turbulence, up to 500 kHz, have been observed on both Faraday rotation and integral density data. Supported by USDOE Grant DE-FC02-04ER54698 and DE-FG03-01ER54615.

  7. Michael Faraday and his contribution to anesthesia.

    PubMed

    Bergman, N A

    1992-10-01

    Michael Faraday (1791-1867) was a protégé of Humphry Davy. He became one of Davy's successors as Professor of Chemistry at the Royal Institution of Great Britain. Of Faraday's many brilliant discoveries in chemistry and physics, probably the best remembered today is his work on electromagnetic induction. Faraday's contribution to introduction of anesthesia was his published announcement in 1818 that inhalation of the vapor of ether produced the same effects on mentation and consciousness as the breathing of nitrous oxide. He most likely became familiar with the central nervous system effects of nitrous oxide through his association with Davy, an avid user of the gas. Sulfuric ether was a common, convenient, cheap, and easily available substance, in contrast to nitrous oxide, which required expensive, cumbersome, and probably not widely available apparatus for its production and administration. The capability for inhaling intoxicating vapors eventually became commonly available with the use of ether instead of the gas. The first surgical anesthetics were a consequence of the resulting student "ether frolics." The 1818 announcement on breathing ether vapor was published anonymously; however, notations in Faraday's handwriting in some of his personal books clearly establish Michael Faraday as the author of this brief communication.

  8. The gravitational analog of Faraday's induction law

    NASA Astrophysics Data System (ADS)

    Zile, Daniel; Overduin, James

    2015-04-01

    Michael Faraday, the discoverer of electromagnetic induction, was convinced that there must also be a gravitational analog of this law, and he carried out drop-tower experiments in 1849 to look for the electric current induced in a coil by changes in gravitational flux through the coil. This work, now little remembered, was in some ways the first investigation of what we would now call a unified-field theory. We revisit Faraday's experiments in the light of current knowledge and ask what might be learned if they were to be performed today. We then review the gravitational analog for Faraday's law that arises within the vector (or gravito-electromagnetic) approximation to Einstein's theory of general relativity in the weak-field, low-velocity limit. This law relates spinning masses and induced ``mass currents'' rather than spinning charges and electric currents, but is otherwise remarkably similar to its electromagnetic counterpart. The predicted effects are completely unobservable in everyday settings like those envisioned by Faraday, but are thought to be relevant in astrophysical contexts like the accretion disks around collapsed stars, thus bearing out Faraday's remarkable intuition. Undergraduate student.

  9. Navy Fast Track Program.

    ERIC Educational Resources Information Center

    Dessel, Norm; Mehaffy, George

    This paper discusses the critical shortage of math and science teachers in San Diego public schools and the necessary revision of the teacher preparation process to provide flexibility in expediting entry into the classroom of candidates with strong academic math/science backgrounds. U.S. Navy officers near retirement who have completed degrees in…

  10. On the Fast Track

    ERIC Educational Resources Information Center

    Selingo, Jeffrey

    2006-01-01

    Northeastern University's continuing-education division is being rejuvenated with market research, faculty involvement, and a non-traditional approach under its new vice president Christopher E. Hopey. The college shifted its emphasis from undergraduates to graduate and certificate programs aimed at working professionals, resulting in a 20 percent…

  11. Fast Tracks to Intelligence

    NASA Astrophysics Data System (ADS)

    Calvin, W. H.

    It is often assumed that the evolution of intelligence is inevitable, given the self-organizing seen in dissapative systems and the gradual shaping-up of Darwinism. While compound-interest reasoning suggests that small advantages will eventually triumph, eventually may be a very long time: there are few examples of rapid brain growth, suggesting that "smarter-is-better" is not a potent force for evolution.

  12. Role of epidural anesthesia in a fast track liver resection protocol for cirrhotic patients - results after three years of practice

    PubMed Central

    Siniscalchi, Antonio; Gamberini, Lorenzo; Bardi, Tommaso; Laici, Cristiana; Gamberini, Elisa; Francorsi, Letizia; Faenza, Stefano

    2016-01-01

    AIM To evaluate the potential benefits and risks of the use of epidural anaesthesia within an enhanced recovery protocol in this specific subpopulation. METHODS A retrospective review was conducted, including all cirrhotic patients who underwent open liver resection between January 2013 and December 2015 at Bologna University Hospital. Patients with an abnormal coagulation profile contraindicating the placement of an epidural catheter were excluded from the analysis. The control group was composed by patients refusing epidural anaesthesia. RESULTS Of the 183 cirrhotic patients undergoing open liver resections, 57 had contraindications to the placement of an epidural catheter; of the remaining 126, 86 patients received general anaesthesia and 40 combined anaesthesia. The two groups presented homogeneous characteristics. Intraoperatively the metabolic data did not differ between the two groups, whilst the epidural group had a lower mean arterial pressure (P = 0.041) and received more colloid infusions (P = 0.007). Postoperative liver and kidney function did not differ significantly. Length of mechanical ventilation (P = 0.003) and hospital stay (P = 0.032) were significantly lower in the epidural group. No complications related to the epidural catheter placement or removal was recorded. CONCLUSION The use of Epidural Anaesthesia within a fast track protocol for cirrhotic patients undergoing liver resections had a positive impact on the patient’s outcomes and comfort as demonstrated by a significantly lower length of mechanical ventilation and hospital stay in the epidural group. The technique appears to be safely manageable in this fragile population even though these results need confirmation in larger studies. PMID:27660677

  13. Preoperative prediction of potentially preventable morbidity after fast-track hip and knee arthroplasty: a detailed descriptive cohort study

    PubMed Central

    Petersen, Morten Aa; Kehlet, Henrik

    2016-01-01

    Objectives Construction of a simple preoperative risk score for patients in high risk of potentially preventable ‘medical’ complications. Secondary objectives were to construct simple preoperative risk scores for ‘severe medical’, ‘surgical’ and ‘total’ potentially preventable complications. Design Prospective observational study. Setting Elective primary unilateral total hip and knee arthroplasty with prospectively collected preoperative patient characteristics; similar standardised fast-track protocols; evaluation of complications through discharge and medical records; and complete 90 days follow-up through nationwide databases. Participants 8373 consecutive unselected total hip arthroplasty (THA) and knee arthroplasty from January 2010 to November 2012. Results There were 557 procedures (6.4%) followed by potentially preventable complications resulting in hospitalisation >4 days or readmission. Of 22 preoperative characteristics, 7 were associated with 379 (4.2%) potentially preventable ‘medical’ complications. Patients with ≥2 of the following, age ≥80 years, anticoagulant therapy, pulmonary disease, pharmacologically treated psychiatric disorder, anaemia and walking aids, composed 19.1% of the procedures; 55.7% constituted potentially preventable ‘medical’ complications that were mainly falls, mobilisation issues, pneumonias and cardiac arrhythmias. The number needed to be treated for a hypothetical intervention leading to 25% reduction in potentially preventable ‘medical’ complications was 34. THA, use of walking aids and cardiac disease were associated with 189 (2.2%) ‘surgical’ complications, but no clinically relevant preoperative prediction was possible. Conclusions Preoperative identification of patients at high risk of preventable ‘medical’, but not ‘surgical’, complications is statistically possible. However, clinical relevance is limited. Future risk indices should differ between ‘medical’ and

  14. Fast Track Reservoir Modeling of Shale Formations in the Appalachian Basin. Application to Lower Huron Shale in Eastern Kentucky

    SciTech Connect

    Grujic, Ognjen; Mohaghegh, Shahab; Bromhal, Grant

    2010-07-01

    In this paper a fast track reservoir modeling and analysis of the Lower Huron Shale in Eastern Kentucky is presented. Unlike conventional reservoir simulation and modeling which is a bottom up approach (geo-cellular model to history matching) this new approach starts by attempting to build a reservoir realization from well production history (Top to Bottom), augmented by core, well-log, well-test and seismic data in order to increase accuracy. This approach requires creation of a large spatial-temporal database that is efficiently handled with state of the art Artificial Intelligence and Data Mining techniques (AI & DM), and therefore it represents an elegant integration of reservoir engineering techniques with Artificial Intelligence and Data Mining. Advantages of this new technique are a) ease of development, b) limited data requirement (as compared to reservoir simulation), and c) speed of analysis. All of the 77 wells used in this study are completed in the Lower Huron Shale and are a part of the Big Sandy Gas field in Eastern Kentucky. Most of the wells have production profiles for more than twenty years. Porosity and thickness data was acquired from the available well logs, while permeability, natural fracture network properties, and fracture aperture data was acquired through a single well history matching process that uses the FRACGEN/NFFLOW simulator package. This technology, known as Top-Down Intelligent Reservoir Modeling, starts with performing conventional reservoir engineering analysis on individual wells such as decline curve analysis and volumetric reserves estimation. Statistical techniques along with information generated from the reservoir engineering analysis contribute to an extensive spatio-temporal database of reservoir behavior. The database is used to develop a cohesive model of the field using fuzzy pattern recognition or similar techniques. The reservoir model is calibrated (history matched) with production history from the most recently

  15. Mode-locking via dissipative Faraday instability

    NASA Astrophysics Data System (ADS)

    Tarasov, Nikita; Perego, Auro M.; Churkin, Dmitry V.; Staliunas, Kestutis; Turitsyn, Sergei K.

    2016-08-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system--spectrally dependent losses--achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  16. Faraday polarization fluctuations of satellite beacon signals

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Klobuchar, J. A.

    1988-01-01

    The anisotropic effects of random density irregularities in causing Faraday polarization fluctuations of VHF radio signals are examined, taking both rod-like and sheet-like irregularities into consideration. It is found that the variance of Faraday polarization fluctuations depends on the ratio of perpendicular to parallel correlation lengths. The anisotropic effect of rod-like ionospheric irregularities are shown to be most appreciable for longitudinal propagation. The anisotropic effect of sheet-like ionospheric irregularities, however, is not strongly dependent on the radio propagation angle. During transionospheric propagation at large angles with respect to the geomagnetic field, sheet-like irregularities may cause greater Faraday polarization fluctuations than rod-like irregularities.

  17. Mode-locking via dissipative Faraday instability

    PubMed Central

    Tarasov, Nikita; Perego, Auro M.; Churkin, Dmitry V.; Staliunas, Kestutis; Turitsyn, Sergei K.

    2016-01-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin–Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system—spectrally dependent losses—achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin–Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering. PMID:27503708

  18. Faraday waves under time-reversed excitation.

    PubMed

    Pietschmann, Dirk; Stannarius, Ralf; Wagner, Christian; John, Thomas

    2013-03-01

    Do parametrically driven systems distinguish periodic excitations that are time mirrors of each other? Faraday waves in a Newtonian fluid are studied under excitation with superimposed harmonic wave forms. We demonstrate that the threshold parameters for the stability of the ground state are insensitive to a time inversion of the driving function. This is a peculiarity of some dynamic systems. The Faraday system shares this property with standard electroconvection in nematic liquid crystals [J. Heuer et al., Phys. Rev. E 78, 036218 (2008)]. In general, time inversion of the excitation affects the asymptotic stability of a parametrically driven system, even when it is described by linear ordinary differential equations. Obviously, the observed symmetry has to be attributed to the particular structure of the underlying differential equation system. The pattern selection of the Faraday waves above threshold, on the other hand, discriminates between time-mirrored excitation functions.

  19. Mode-locking via dissipative Faraday instability.

    PubMed

    Tarasov, Nikita; Perego, Auro M; Churkin, Dmitry V; Staliunas, Kestutis; Turitsyn, Sergei K

    2016-08-09

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system-spectrally dependent losses-achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  20. Calibrated Faraday Current And Magnetic Field Sensor

    NASA Astrophysics Data System (ADS)

    Neyer, B. T.; Chang, J.; Ruggles, L. E.

    1986-01-01

    We have developed a calibrated optical fiber Faraday rotation current sensor. A strong magnetic field in an optical fiber introduces circular birefringence, causing the plane of polarization of light to rotate by an amount proportional to the magnetic field. Faraday loops used in the past were nonlinear due to the stress-induced linear birefringence caused by bending the loop. This linear birefringence interfered with the Faraday rotation, yielding a complicated relationship between the current and detected light signal. We have found a way to overcome the effects of the unwanted linear birefringence and produce a calibrated current waveform. The calibration is limited only by the accurate knowledge of the Verdet constant of the optical fiber. Results of recent experiments as well as planned measurements will be presented.

  1. Rapid determination of Faraday rotation in optical glasses by means of secondary Faraday modulator.

    PubMed

    Sofronie, M; Elisa, M; Sava, B A; Boroica, L; Valeanu, M; Kuncser, V

    2015-05-01

    A rapid high sensitive method for determining the Faraday rotation of optical glasses is proposed. Starting from an experimental setup based on a Faraday rod coupled to a lock-in amplifier in the detection chain, two methodologies were developed for providing reliable results on samples presenting low and large Faraday rotations. The proposed methodologies were critically discussed and compared, via results obtained in transmission geometry, on a new series of aluminophosphate glasses with or without rare-earth doping ions. An example on how the method can be used for a rapid examination of the optical homogeneity of the sample with respect to magneto-optical effects is also provided.

  2. A potassium Faraday anomalous dispersion optical filter

    NASA Technical Reports Server (NTRS)

    Yin, B.; Shay, T. M.

    1992-01-01

    The characteristics of a potassium Faraday anomalous dispersion optical filter operating on the blue and near infrared transitions are calculated. The results show that the filter can be designed to provide high transmission, very narrow pass bandwidth, and low equivalent noise bandwidth. The Faraday anomalous dispersion optical filter (FADOF) provides a narrow pass bandwidth (about GHz) optical filter for laser communications, remote sensing, and lidar. The general theoretical model for the FADOF has been established in our previous paper. In this paper, we have identified the optimum operational conditions for a potassium FADOF operating on the blue and infrared transitions. The signal transmission, bandwidth, and equivalent noise bandwidth (ENBW) are also calculated.

  3. Evidence of high-frequency/small-scale turbulence in the Cygnus region and anomalous Faraday rotation

    NASA Astrophysics Data System (ADS)

    Medvedev, Mikhail V.

    2017-01-01

    Faraday effect - a common and useful probe of cosmic magnetic fields - is the result of magnetically-induced birefringence in plasmas causing rotation of the polarization plane of a linearly polarized electromagnetic wave. Classically, the rotation angle scales with the wavelength as Δϕ =RMλ2 , where RM is the rotation measure. Although a typical RM in the Milky Way is of the order of a few hundred to a few thousand, a famous Cygnus region shows anomalously small, even negative rotation measures. Moreover, Faraday rotation measurements seem to be inconsistent with the standard λ2-law. We argue that fast micro-turbulence can cause this anomaly. We demonstrate that electromagnetic high-frequency and/or small-scale fluctuations can lead to effective plasma collisionality by scattering electrons over pitch-angle. We show that such quasi-collisionality radically alters Faraday rotation and other radiative transport properties, e.g., absorption, transmission and reflection. Thus, we explain the Cygnus puzzle by anomalous Faraday rotation in a thin ``blanket'' of highly turbulent plasma at the front of an interstellar bubble/shock. Supported by DOE grant DE-SC0016368.

  4. Faraday current sensing employing chromatic modulation

    NASA Astrophysics Data System (ADS)

    Jones, G. R.; Li, G.; Spencer, J. W.; Aspey, R. A.; Kong, M. G.

    1998-01-01

    Faraday current sensors using a variety of sensing elements have been investigated extensively for their high sensitivity as well as other advantages [G.L. Lewis et al., Proc. IEE Conf. on The Reliability of Transmission and Distribution Equipment, 1995; Y.N. Ning et al., Optics Lett. 16 (1991); C.M.M. van den Tempel, Appl. Optics 32 (1993)]. Concurrently chromatic modulation techniques have been investigated at the University of Liverpool for use with optical fibre sensors of different types [N.A. Pilling, Ph.D. Thesis, 1992; M.M. Murphy, Ph.D. Thesis, 1991] including Faraday current sensing, for overcoming difficulties with non-referenced intensity modulation systems. In this contribution a brief discussion of the scope of chromatically based Faraday current sensing with particular regard to electric power transmission and distribution industries is given. A novel sensor based upon a Faraday glass block in combination with a BSO crystal in the sensing element is described. The sensor takes advantage of the natural gyrotropy of the BSO which conversely has been previously regarded as a disadvantage. The experimental results obtained indicate that this method offers a novel approach to improving system sensitivity. The extension of the approach from a simple bench top demonstrator to real power systems deployment is also discussed.

  5. QUANTUM ELECTRONIC DEVICES: Cryogenic Faraday isolator

    NASA Astrophysics Data System (ADS)

    Zheleznov, D. S.; Zelenogorskii, V. V.; Katin, E. V.; Mukhin, I. B.; Palashov, O. V.; Khazanov, Efim A.

    2010-05-01

    A Faraday isolator is described in which thermal effects are suppressed by cooling down to liquid nitrogen temperatures. The principal scheme, main characteristics and modifications of the isolator are presented. The isolation degree is studied experimentally for the subkilowatt average laser radiation power. It is shown that the isolator can be used at radiation powers up to tens of kilowatts.

  6. Reflections of a Faraday Challenge Day Leader

    ERIC Educational Resources Information Center

    Sewell, Keira

    2014-01-01

    Keira Sewell has just finished her second year as a Challenge Leader for the Faraday Challenge, a STEM-based scheme run by the Institution of Engineering and Technology. Aimed at 12-13 year-old students, its purpose is to engage students in future careers in engineering. Each year, a new challenge is held in over sixty schools and universities…

  7. Fiber optic, Faraday rotation current sensor

    SciTech Connect

    Veeser, L.R.; Day, G.W.

    1986-01-01

    At the Second Megagauss Conference in 1979, there were reports of experiments that used the Faraday magneto-optic effect in a glass rod to measure large electric current pulses or magnetic fields. Since then we have seen the development of single-mode optical fibers that can carry polarized light in a closed loop around a current load. A fiber optic Faraday rotation sensor will integrate the flux, instead of sampling it at a discrete point, to get a measurement independent of the current distribution. Early Faraday rotation experiments using optical fibers to measure currents dealt with problems such as fiber birefringence and difficulties in launching light into the tiny fiber cores. We have built on those experiments, working to reduce the effects of shocks and obtaining higher bandwidths, absolute calibration, and computerized recording and data analysis, to develop the Faraday rotation sensors into a routine current diagnostic. For large current pulses we find reduced sensitivity to electromagnetic interference and other backgrounds than for Rogowski loops; often the fiber optic sensors are useful where conductive probes cannot be used at all. In this paper we describe the fiber optic sensors and some practical matters involved in fielding them.

  8. The Minus Sign in Faraday's Law Revisited

    ERIC Educational Resources Information Center

    O'Sullivan, Colm; Hurley, Donal

    2013-01-01

    By introducing the mathematical concept of orientation, the significance of the minus sign in Faraday's law may be made clear to students with some knowledge of vector calculus. For many students, however, the traditional approach of treating the law as a relationship between positive scalars and of relying on Lenz's law to provide the information…

  9. Design and modeling of Faraday cages for substrate noise isolation

    NASA Astrophysics Data System (ADS)

    Wu, Joyce H.; del Alamo, Jesús A.

    2013-07-01

    A Faraday cage structure using through-substrate vias is an effective strategy to suppress substrate crosstalk, particularly at high frequencies. Faraday cages can reduce substrate noise by 32 dB at 10 GHz, and 26 dB at 50 GHz. We have developed lumped-element, equivalent circuit models of the Faraday cages and test structures to better understand the performance of the Faraday cages. These models compare well to measured results and show that the vias of the Faraday cage act as an RLC shunt to ground that draws substrate current. Designing a Faraday cage to achieve optimum isolation requires low via impedance and mitigation of via sidewall capacitance. The Faraday cage inductance is correlated to the number of vias and via spacing of the cage and can be optimized for the frequency of operation.

  10. How Fast Is Your Body Motion? Determining a Sufficient Frame Rate for an Optical Motion Tracking System Using Passive Markers.

    PubMed

    Song, Min-Ho; Godøy, Rolf Inge

    2016-01-01

    This paper addresses how to determine a sufficient frame (sampling) rate for an optical motion tracking system using passive reflective markers. When using passive markers for the optical motion tracking, avoiding identity confusion between the markers becomes a problem as the speed of motion increases, necessitating a higher frame rate to avoid a failure of the motion tracking caused by marker confusions and/or dropouts. Initially, one might believe that the Nyquist-Shannon sampling rate estimated from the assumed maximal temporal variation of a motion (i.e. a sampling rate at least twice that of the maximum motion frequency) could be the complete solution to the problem. However, this paper shows that also the spatial distance between the markers should be taken into account in determining the suitable frame rate of an optical motion tracking with passive markers. In this paper, a frame rate criterion for the optical tracking using passive markers is theoretically derived and also experimentally verified using a high-quality optical motion tracking system. Both the theoretical and the experimental results showed that the minimum frame rate is proportional to the ratio between the maximum speed of the motion and the minimum spacing between markers, and may also be predicted precisely if the proportional constant is known in advance. The inverse of the proportional constant is here defined as the tracking efficiency constant and it can be easily determined with some test measurements. Moreover, this newly defined constant can provide a new way of evaluating the tracking algorithm performance of an optical tracking system.

  11. How Fast Is Your Body Motion? Determining a Sufficient Frame Rate for an Optical Motion Tracking System Using Passive Markers

    PubMed Central

    Song, Min-Ho; Godøy, Rolf Inge

    2016-01-01

    This paper addresses how to determine a sufficient frame (sampling) rate for an optical motion tracking system using passive reflective markers. When using passive markers for the optical motion tracking, avoiding identity confusion between the markers becomes a problem as the speed of motion increases, necessitating a higher frame rate to avoid a failure of the motion tracking caused by marker confusions and/or dropouts. Initially, one might believe that the Nyquist-Shannon sampling rate estimated from the assumed maximal temporal variation of a motion (i.e. a sampling rate at least twice that of the maximum motion frequency) could be the complete solution to the problem. However, this paper shows that also the spatial distance between the markers should be taken into account in determining the suitable frame rate of an optical motion tracking with passive markers. In this paper, a frame rate criterion for the optical tracking using passive markers is theoretically derived and also experimentally verified using a high-quality optical motion tracking system. Both the theoretical and the experimental results showed that the minimum frame rate is proportional to the ratio between the maximum speed of the motion and the minimum spacing between markers, and may also be predicted precisely if the proportional constant is known in advance. The inverse of the proportional constant is here defined as the tracking efficiency constant and it can be easily determined with some test measurements. Moreover, this newly defined constant can provide a new way of evaluating the tracking algorithm performance of an optical tracking system. PMID:26967900

  12. What Is Required to End the AIDS Epidemic as a Public Health Threat by 2030? The Cost and Impact of the Fast-Track Approach

    PubMed Central

    Stover, John; Bollinger, Lori; Izazola, Jose Antonio; Loures, Luiz; DeLay, Paul; Ghys, Peter D.

    2016-01-01

    In 2011 a new Investment Framework was proposed that described how the scale-up of key HIV interventions could dramatically reduce new HIV infections and AIDS-related deaths in low and middle income countries by 2015. This framework included ambitious coverage goals for prevention and treatment services for 2015, resulting in a reduction of new HIV infections by more than half, in line with the goals of the declaration of the UN High Level Meeting in June 2011. However, the approach suggested a leveling in the number of new infections at about 1 million annually—far from the UNAIDS goal of ending AIDS by 2030. In response, UNAIDS has developed the Fast-Track approach that is intended to provide a roadmap to the actions required to achieve this goal. The Fast-Track approach is predicated on a rapid scale-up of focused, effective prevention and treatment services over the next 5 years and then maintaining a high level of programme implementation until 2030. Fast-Track aims to reduce new infections and AIDS-related deaths by 90% from 2010 to 2030 and proposes a set of biomedical, behavioral and enabling intervention targets for 2020 and 2030 to achieve that goal, including the rapid scale-up initiative for antiretroviral treatment known as 90-90-90. Compared to a counterfactual scenario of constant coverage for all services at early-2015 levels, the Fast-Track approach would avert 18 million HIV infections and 11 million deaths from 2016 to 2030 globally. This paper describes the analysis that produced these targets and the estimated resources needed to achieve them in low- and middle-income countries. It indicates that it is possible to achieve these goals with a significant push to achieve rapid scale-up of key interventions between now and 2020. The annual resources required from all sources would rise to US$7.4Bn in low-income countries, US$8.2Bn in lower middle-income countries and US$10.5Bn in upper-middle-income-countries by 2020 before declining

  13. The performance of the γ-ray tracking array GRETINA for γ-ray spectroscopy with fast beams of rare isotopes

    NASA Astrophysics Data System (ADS)

    Weisshaar, D.; Bazin, D.; Bender, P. C.; Campbell, C. M.; Recchia, F.; Bader, V.; Baugher, T.; Belarge, J.; Carpenter, M. P.; Crawford, H. L.; Cromaz, M.; Elman, B.; Fallon, P.; Forney, A.; Gade, A.; Harker, J.; Kobayashi, N.; Langer, C.; Lauritsen, T.; Lee, I. Y.; Lemasson, A.; Longfellow, B.; Lunderberg, E.; Macchiavelli, A. O.; Miki, K.; Momiyama, S.; Noji, S.; Radford, D. C.; Scott, M.; Sethi, J.; Stroberg, S. R.; Sullivan, C.; Titus, R.; Wiens, A.; Williams, S.; Wimmer, K.; Zhu, S.

    2017-03-01

    The γ-ray tracking array GRETINA was coupled to the S800 magnetic spectrometer for spectroscopy with fast beams of rare isotopes at the National Superconducting Cyclotron Laboratory on the campus of Michigan State University. We describe the technical details of this powerful setup and report on GRETINA's performance achieved with source and in-beam measurements. The γ-ray multiplicity encountered in experiments with fast beams is usually low, allowing for a simplified and efficient treatment of the data in the γ-ray analysis in terms of Doppler reconstruction and spectral quality. The results reported in this work were obtained from GRETINA consisting of 8 detector modules hosting four high-purity germanium crystals each. Currently, GRETINA consists of 10 detector modules.

  14. Growth, Faraday and inverse Faraday characteristics of Tb2Ti2O7 crystal.

    PubMed

    Guo, Feiyun; Sun, Yilin; Yang, Xiongsheng; Chen, Xin; Zhao, Bin; Zhuang, Naifeng; Chen, Jianzhong

    2016-03-21

    Tb2Ti2O7 (TTO) single crystal with dimensions of 20 × 20 × 16 mm3 was grown by the Czochralski method. Rietveld structure refinement of X-ray diffraction (XRD) data confirms that the compound crystallizes in the cubic system with pyrochlore structure. Transmission spectra, Magnetic circular dichroism (MCD) spectra, Faraday and inverse Faraday characteristics of TTO crystal have been measured and analyzed in detail. The results demonstrate that TTO crystal has high transmittance at 700-1400 nm waveband and a larger Verdat constant than that of TGG reported. Magnetic circular dichroism (MCD) spectra showed that the 4f→4f transitions of Tb3+ have significant contributions to the magneto-optical activity (MOA). In the time-resolved pump-probe spectroscopy, the rotation signals of the probe beam based on the inverse Faraday effect in magneto-optical crystal were observed at zero time delay, the full width at half maximum of the rotation and ellipticity signals can be as fast as ~500 fs, which indicates that TTO crystal can be a promising material for ultrafast all-optical magnetic switching.

  15. Fast and accurate calibration of an X-ray imager to an electromagnetic tracking system for interventional cardiac procedures.

    PubMed

    Lang, Andrew; Stanton, Douglas; Parthasarathy, Vijay; Jain, Ameet

    2010-01-01

    Cardiovascular disease affects millions of Americans each year. Interventional guidance systems are being developed as treatment options for some of the more delicate procedures, including targeted stem cell therapy. As advanced systems for such types of interventional guidance are being developed, electromagnetic (EM) tracking is coming in demand to perform navigation. To use this EM tracking technology, a calibration is necessary to register the tracker to the imaging system. In this paper we investigate the calibration of an X-ray imaging system to EM tracking. Two specially designed calibration phantoms have been designed for this purpose, each having a rigidly attached EM sensor. From a clinical usability point-of-view, we propose to divide this calibration problem into two steps: i) in initial calibration of the EM sensor to the phantom design using an EM tracked needle to trace out grooves in the phantom surface and ii) segmentation from X-ray images and 3D reconstruction of beads embedded in the phantom in a known geometric pattern. Combining these two steps yields and X-ray-to-EM calibration accuracy of less than 1 mm when overlaying an EM tracked needle on X-ray images.

  16. In-vacuum Faraday isolation remote tuning.

    PubMed

    Accadia, T; Acernese, F; Antonucci, F; Aoudia, S; Arun, K G; Astone, P; Ballardin, G; Barone, F; Barsuglia, M; Bauer, Th S; Beker, M G; Bigotta, S; Birindelli, S; Bitossi, M; Bizouard, M A; Blom, M; Boccara, C; Bondu, F; Bonelli, L; Bosi, L; Braccini, S; Bradaschia, C; Brillet, A; Brisson; Budzynski, R; Bulik, T; Bulten, H J; Buskulic, D; Cagnoli, G; Calloni, E; Campagna, E; Canuel, B; Carbognani, F; Cavalier, F; Cavalieri, R; Cella, G; Cesarini, E; Chassande-Mottin, E; Chincarini, A; Cleva, F; Coccia, E; Colacino, C N; Colas, J; Colla, A; Colombini, M; Corda, C; Corsi, A; Coulon, J-P; Cuoco, E; D'Antonio, S; Dari, A; Dattilo, V; Davier, M; Day, R; De Rosa, R; del Prete, M; Di Fiore, L; Di Lieto, A; Emilio, M Di Paolo; Di Virgilio, A; Dietz, A; Drago, M; Fafone, V; Ferrante, I; Fidecaro, F; Fiori, I; Flaminio, R; Fournier, J-D; Franc, J; Frasca, S; Frasconi, F; Freise, A; Gammaitoni, L; Garufi, F; Gemme, G; Genin, E; Gennai, A; Giazotto, A; Gouaty, R; Granata, M; Greverie, C; Guidi, G M; Heitmann, H; Hello, P; Hild, S; Huet, D; Jaranowski, P; Kowalska, I; Królak, A; La Penna, P; Leroy, N; Letendre, N; Li, T G F; Lorenzini, M; Loriette, V; Losurdo, G; Mackowski, J M; Majorana, E; Man, N; Mantovani, M; Marchesoni, F; Marion, F; Marque, J; Martelli, F; Masserot, A; Michel, C; Milano, L; Minenkov, Y; Mohan, M; Moreau, J; Morgado, N; Morgia, A; Mosca, S; Moscatelli, V; Mours, B; Neri, I; Nocera, F; Pagliaroli, G; Palladino, L; Palomba, C; Paoletti, F; Pardi, S; Parisi, M; Pasqualetti, A; Passaquieti, R; Passuello, D; Persichetti, G; Pichot, M; Piergiovanni, F; Pietka, M; Pinard, L; Poggiani, R; Prato, M; Prodi, G A; Punturo, M; Puppo, P; Rabaste, O; Rabeling, D S; Rapagnani, P; Re, V; Regimbau, T; Ricci, F; Robinet, F; Rocchi, A; Rolland, L; Romano, R; Rosińska, D; Ruggi, P; Sassolas, B; Sentenac, D; Sturani, R; Swinkels, B; Toncelli, A; Tonelli, M; Tournefier, E; Travasso, F; Trummer, J; Vajentei, G; van den Brand, J F J; van der Putten, S; Vavoulidis, M; Vedovato, G; Verkindt, D; Vetrano, F; Viceré, A; Vinet, J-Y; Vocca, H; Was, M; Yvert, M

    2010-09-01

    In-vacuum Faraday isolators (FIs) are used in gravitational wave interferometers to prevent the disturbance caused by light reflected back to the input port from the interferometer itself. The efficiency of the optical isolation is becoming more critical with the increase of laser input power. An in-vacuum FI, used in a gravitational wave experiment (Virgo), has a 20 mm clear aperture and is illuminated by an almost 20 W incoming beam, having a diameter of about 5 mm. When going in vacuum at 10(-6) mbar, a degradation of the isolation exceeding 10 dB was observed. A remotely controlled system using a motorized lambda=2 waveplate inserted between the first polarizer and the Faraday rotator has proven its capability to restore the optical isolation to a value close to the one set up in air.

  17. Faraday's first dynamo: An alternate analysis

    NASA Astrophysics Data System (ADS)

    Redinz, José Arnaldo

    2015-02-01

    The steady-state charge densities, electric potential, and current densities are determined analytically in the case of the first dynamo created by Michael Faraday, which consists of a conducting disk rotating between the poles of an off-axis permanent magnet. The results obtained are compared with another work that considered the same problem using a different approach. We also obtain analytical expressions for the total current on the disk and for the dynamo's electromotive force.

  18. Modelling Faraday Screens in the Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Wolleben, M.; Reich, W.

    2004-02-01

    Maps of Galactic polarized continuum emission at 1408, 1660, and 1713 MHz towards the local Taurus molecular cloud complex were made with the Effelsberg 100-m telescope. Minima in the polarized emission which are located at the boundary of a molecular cloud were detected. Beside high rotation measures and unusual spectral indices of the polarized intensity, these features are associated with the molecular gas. At the higher frequencies the minima get less distinct. We have modelled the multi-frequency observations by placing magneto-ionic Faraday screens at the distance of the molecular cloud. In this model Faraday rotated background emission adds to foreground emission towards these screens. The systematic variation of the observed properties is the result of different line-of-sight lengths through the screen assuming spherical symmetry. For a distance of 140 pc to the Taurus clouds the physical sizes of the Faraday screens are of the order of 2 pc. In this paper we describe the data calibration and modelling process for one such object. We find an intrinsic rotation measure of about -29 rad m-2 to model the observations. It is pointed out that the observed rotation measure differs from the physical. Further observational constraints from Hα observations limit the thermal electron density to less than 0.8 cm-3, and we conclude that the regular magnetic field strength parallel to the line-of-sight exceeds 20 μG to account for the intrinsic rotation measure.

  19. MUSIC for Faraday rotation measure synthesis

    NASA Astrophysics Data System (ADS)

    Andrecut, M.

    2013-03-01

    Faraday rotation measure (RM) synthesis requires the recovery of the Faraday dispersion function (FDF) from measurements restricted to limited wavelength ranges, which is an ill-conditioned deconvolution problem. Here, we propose a novel deconvolution method based on an extension of the MUltiple SIgnal Classification (MUSIC) algorithm. The complexity and speed of the method is determined by the eigen-decomposition of the covariance matrix of the observed polarizations. We show numerically that for high to moderate signal-to-noise ratio (S/N) cases the RM-MUSIC method is able to recover the Faraday depth values of closely spaced pairs of thin RM components, even in situations where the peak response of the FDF is outside of the RM range between the two input RM components. This result is particularly important because the standard deconvolution approach based on RM-CLEAN fails systematically in such situations, due to its greedy mechanism used to extract the RM components. For low S/N situations, both the RM-MUSIC and RM-CLEAN methods provide similar results.

  20. Tracking the speech signal--time-locked MEG signals during perception of ultra-fast and moderately fast speech in blind and in sighted listeners.

    PubMed

    Hertrich, Ingo; Dietrich, Susanne; Ackermann, Hermann

    2013-01-01

    Blind people can learn to understand speech at ultra-high syllable rates (ca. 20 syllables/s), a capability associated with hemodynamic activation of the central-visual system. To further elucidate the neural mechanisms underlying this skill, magnetoencephalographic (MEG) measurements during listening to sentence utterances were cross-correlated with time courses derived from the speech signal (envelope, syllable onsets and pitch periodicity) to capture phase-locked MEG components (14 blind, 12 sighted subjects; speech rate=8 or 16 syllables/s, pre-defined source regions: auditory and visual cortex, inferior frontal gyrus). Blind individuals showed stronger phase locking in auditory cortex than sighted controls, and right-hemisphere visual cortex activity correlated with syllable onsets in case of ultra-fast speech. Furthermore, inferior-frontal MEG components time-locked to pitch periodicity displayed opposite lateralization effects in sighted (towards right hemisphere) and blind subjects (left). Thus, ultra-fast speech comprehension in blind individuals appears associated with changes in early signal-related processing mechanisms both within and outside the central-auditory terrain.

  1. Competing Turing and Faraday Instabilities in Longitudinally Modulated Passive Resonators.

    PubMed

    Copie, François; Conforti, Matteo; Kudlinski, Alexandre; Mussot, Arnaud; Trillo, Stefano

    2016-04-08

    We experimentally investigate the interplay of Turing (modulational) and Faraday (parametric) instabilities in a bistable passive nonlinear resonator. The Faraday branch is induced via parametric resonance owing to a periodic modulation of the resonator dispersion. We show that the bistable switching dynamics is dramatically affected by the competition between the two instability mechanisms, which dictates two completely novel scenarios. At low detunings from resonance, switching occurs between the stable stationary lower branch and the Faraday-unstable upper branch, whereas at high detunings we observe the crossover between the Turing and Faraday periodic structures. The results are well explained in terms of the universal Lugiato-Lefever model.

  2. Very large array faraday rotation studies of the coronal plasma

    NASA Astrophysics Data System (ADS)

    Kooi, Jason Earl

    Knowledge of the coronal magnetic field is crucial for understanding (1) the heating mechanism(s) of the solar corona, (2) the acceleration of the fast solar wind, and (3) the structure and dynamics of coronal mass ejections (CMEs). Observation of Faraday rotation (FR) is one of the best remote-sensing techniques for determining plasma properties in the corona and can provide information on the plasma structure of a CME shortly after launch, shedding light on the initiation process. I used the Karl G. Jansky Very Large Array (VLA) to make sensitive Faraday rotation measurements to investigate the general plasma structure of the corona, properties of coronal plasma inhomogeneities and waves, and transients associated with coronal mass ejections. To enhance my measurements of FR transients, I also developed an algorithm in the Common Astronomy Software Applications (CASA) package to mitigate ionospheric Faraday rotation. In August, 2011, I made FR observations at 5.0 and 6.1 GHz of the radio galaxy 3C 228 through the solar corona at heliocentric distances of 4.6-5.0 solar radii using the VLA. Observations at 5.0 GHz permit measurements deeper in the corona than previous VLA observations at 1.4 and 1.7 GHz. These FR observations provided unique information on the magnetic field in this region of the corona. My data on 3C 228 provide two lines of sight (separated by 46 arcseconds, 33,000 km in the corona). I detected three periods during which there appeared to be a difference in the Faraday rotation measure between these two closely spaced lines of sight, which I used to estimate coronal currents; these values (ranging from 2.6 to 4.1 GA) are several orders of magnitude below that which is necessary for significant coronal heating (assuming the Spitzer resistivity). I also used the data to determine upper limits (3.3 and 6.4 rad/m2 along the two lines of sight) on FR fluctuations caused by coronal waves. These upper limits are comparable to and, thus, not inconsistent

  3. Tracking and Pointing of Target by a Bifocal Relay Mirror Spacecraft Using Attitude Control and Fast Steering Mirrors Tilting

    DTIC Science & Technology

    2002-08-01

    proposed for the tracking and pointing of the target of the Bifocal Relay Mirror. The attitude control system consists of reaction wheels , star trackers and...nautics, Inc. with permission. T Transmitter portion of the spacecraft w Reaction wheel m Mirror rel Relative B Acronyms BRM Bifocal Relay Mirror...tem are respectively OR and OS . The other bodies considered in the dynamic model are: • four reaction wheels mounted in tetrahedral configuration on

  4. A fast-track anaemia clinic in the Emergency Department: feasibility and efficacy of intravenous iron administration for treating sub-acute iron deficiency anaemia

    PubMed Central

    Quintana-Díaz, Manuel; Fabra-Cadenas, Sara; Gómez-Ramírez, Susana; Martínez-Virto, Ana; García-Erce, José A.; Muñoz, Manuel

    2016-01-01

    Background Clinically significant anaemia, requiring red blood cell transfusions, is frequently observed in Emergency Departments (ED). To optimise blood product use, we developed a clinical protocol for the management of iron-deficiency anaemia in a fast-track anaemia clinic within the ED. Materials and methods From November 2010 to January 2014, patients presenting with sub-acute, moderate-to-severe anaemia (haemoglobin [Hb] <11 g/dL) and confirmed or suspected iron deficiency were referred to the fast-track anaemia clinic. Those with absolute or functional iron deficiency were given intravenous (IV) ferric carboxymaltose 500–1,000 mg/week and were reassessed 4 weeks after receiving the total iron dose. The primary study outcome was the haematological response (Hb≥12 g/dL and/or Hb increment ≥2 g/dL). Changes in blood and iron parameters, transfusion rates and IV iron-related adverse drug effects were secondary outcomes. Results Two hundred and two anaemic patients with iron deficiency (150 women/52 men; mean age, 64 years) were managed in the fast-track anaemia clinic, and received a median IV iron dose of 1,500 mg (1,000–2,000 mg). Gastro-intestinal (44%) or gynaecological (26%) bleeding was the most frequent cause of the anaemia. At follow-up (183 patients), the mean Hb increment was 3.9±2.2 g/dL; 84% of patients were classified as responders and blood and iron parameters normalised in 90%. During follow-up, 35 (17%) patients needed transfusions (2 [range: 1–3] units per patient) because they had low Hb levels, symptoms of anaemia and/or were at risk. Eight mild and one moderate, self-limited adverse drug effects were witnessed. Discussion Our data support the feasibility of a clinical protocol for management of sub-acute anaemia with IV iron in the ED. IV iron was efficacious, safe and well tolerated. Early management of anaemia will improve the use of blood products in the ED. PMID:26674819

  5. Faraday screens associated with local molecular clouds

    NASA Astrophysics Data System (ADS)

    Wolleben, M.; Reich, W.

    2004-11-01

    Polarization observations at λ 21 cm and λ 18 cm towards the local Taurus molecular cloud complex were made with the Effelsberg 100-m telescope. Highly structured, frequency-dependent polarized emission features were detected. We discuss polarization minima with excessive rotation m easures located at the boundaries of molecular clouds. These minima get less pronounced at the higher frequencies. The multi-frequency polarization data have been successfully modeled by considering magneto-ionic Faraday screens at the surface of the molecular clouds. Faraday rotated background emiss ion adds to foreground emission towards these screens in a different way than in its surroundings. The physical size of the Faraday screens is of the order of 2 pc for 140 pc distance to the Taurus clouds. Intrinsic rotation measures between about -18 rad m-2 to -30 rad m-2 are required to model the observations. Depolarization of the background emission is quite small (compatible with zero), indicating a regular magnetic field structure with little turbulence within the Faraday screens. With observational {constraints} for the thermal electron density from Hα observations of less than 0.8 cm-3 we conclude that the regular magnetic field strength along the line of sight exceeds 20 μ G, to account for the observed rotation measure. We discuss some possibilities for the origin of such strong and well ordered magnetic fields. The modeling also predicts a large-scale, regularly polarized emission in the foreground of the Taurus clouds which is of the order of 0.18 K at λ 21 cm. This in turn constrains the observed synchrotron emission in total intensity within 140 pc of the Taurus clouds. A lower limit of about 0.24 K, or about 1.7 K/kpc, is required for a perfectly ordered magnetic field with intrinsic (˜ 75%) percentage polarization. Since this is rather unlikely to be the case, the fraction of foreground synchrotron emission is even larger. This amount of synchrotron emission is

  6. Observation of Phillips's spectrum in Faraday waves

    NASA Astrophysics Data System (ADS)

    Castillo, Gustavo; Falcon, Claudio

    2016-11-01

    We consider the problem of wave turbulence generated by singularities from an experimental point of view. We study a system of Faraday waves interacting with waves generated by a wave-maker driven with a random forcing. We measure the temporal fluctuations of the surface wave amplitude at a given location and we show that for a wide range of forcing parameters the surface height displays a power-law spectra that greatly differs from the one predicted by the WT theory. In the capillary region the power spectrum turns out to be proportional to f-5, which we believe is due to singularities moving across the system. Proyecto Postdoctorado Fondecyt Nro 3160032.

  7. C60 as a Faraday cage

    NASA Astrophysics Data System (ADS)

    Delaney, P.; Greer, J. C.

    2004-01-01

    Endohedral fullerenes have been proposed for a number of technological uses, for example, as a nanoscale switch, memory bit and as qubits for quantum computation. For these technology applications, it is important to know the ease with which the endohedral atom can be manipulated using an applied electric field. We find that the Buckminsterfullerene (C60) acts effectively as a small Faraday cage, with only 25% of the field penetrating the interior of the molecule. Thus influencing the atom is difficult, but as a qubit the endohedral atom should be well shielded from environmental electrical noise. We also predict how the field penetration should increase with the fullerene radius.

  8. Faraday isolator based on TSAG crystal for high power lasers.

    PubMed

    Mironov, E A; Palashov, O V

    2014-09-22

    A Faraday isolator based on a new magneto-optical medium, TSAG (terbium scandium aluminum garnet) crystal, has been constructed and investigated experimentally. The device provides an isolation ratio of more than 30 dB at 500 W laser power. It is shown that this medium can be used in Faraday isolators for kilowatt-level laser powers.

  9. A note on random excitation of nonlinear Faraday waves

    NASA Astrophysics Data System (ADS)

    Miles, John

    2004-06-01

    The evolution equations for weakly nonlinear Faraday waves in a cylinder that is subjected to a narrow-band, random acceleration are constructed and shown to be isomorphic to Repetto and Galletta's ["Finite amplitude Faraday waves induced by random forcing," Phys. Fluids 14, 4284 (2002)] results for the two-dimensional problem, which, therefore, are applicable to laboratory experiments in circular cylinders.

  10. Rethinking Faraday's Law for Teaching Motional Electromotive Force

    ERIC Educational Resources Information Center

    Zuza, Kristina; Guisasola, Jenaro; Michelini, Marisa; Santi, Lorenzo

    2012-01-01

    This study shows physicists' discussions on the meaning of Faraday's law where situations involving extended conductors or moving contact points are particularly troublesome. We raise questions to test students' difficulties in applying Faraday's law in motional electromotive force phenomena. We suggest the benefit of analysing these phenomena…

  11. Laser-Based Faraday-Effect Measurement of Magnetic Fluctuations and Fluctuation-Induced Transport

    NASA Astrophysics Data System (ADS)

    Lin, L.; Brower, D. L.; Ding, W. X.; Sarff, J. S.

    2013-10-01

    A multichord far-infrared laser-based Faraday-effect polarimetry diagnostic has been well developed on MST. Combined polarimetry-interferometry capability permits simultaneous measurement of internal structure of density and magnetic field with fast time response (~ 4 μs) and low phase noise (< 0 .01°) . With this diagnostic, the impact on toroidal current profile from a tangentially injected neutral beam is directly measured, allowing evaluation of non-inductive current drive. In addition, 0 .05° Faraday-effect fluctuations associated with global tearing modes are resolved with an uncertainty below 0 .01° . For physics investigations, these Faraday-effect fluctuations are complicated by contributions from both density and magnetic fluctuations. In our analysis, the local density fluctuations are obtained by inverting the line-integrated interferometry data after resolving the mode helicity through correlation techniques. The local magnetic fluctuations are then reconstructed using a parameterized fit of the polarimetry data, accounting for both the density and magnetic contributions. For the same mode, density and radial magnetic fluctuations exhibit very different spatial structure. In this process, their relative phase is also determined, thereby allowing the determination of magnetic-fluctuation-induced transport. Work supported by US DoE.

  12. Searching for Faraday rotation in cosmic microwave background polarization

    NASA Astrophysics Data System (ADS)

    Ruiz-Granados, B.; Battaner, E.; Florido, E.

    2016-08-01

    We use the Wilkinson Microwave Anisotropy Probe (WMAP) 9th-year foreground reduced data at 33, 41 and 61 GHz to derive a Faraday rotation at map and at angular power spectrum levels taking into account their observational errors. A processing mask provided by WMAP is used to avoid contamination from the disc of our Galaxy and local spurs. We have found a Faraday rotation component at both, map and power spectrum levels. The lack of correlation of the Faraday rotation with Galactic Faraday rotation, synchrotron and dust polarization from our Galaxy or with cosmic microwave background anisotropies or lensing suggests that it could be originated at reionization (ℓ ≲ 12). Even if the detected Faraday rotation signal is weak, the present study could contribute to establish magnetic fields strengths of B0 ˜ 10-8 G at reionization.

  13. Fast ion conductivity in strained defect-fluorite structure created by ion tracks in Gd2Ti2O7

    PubMed Central

    Aidhy, Dilpuneet S.; Sachan, Ritesh; Zarkadoula, Eva; Pakarinen, Olli; Chisholm, Matthew F.; Zhang, Yanwen; Weber, William J.

    2015-01-01

    The structure and ion-conducting properties of the defect-fluorite ring structure formed around amorphous ion-tracks by swift heavy ion irradiation of Gd2Ti2O7 pyrochlore are investigated. High angle annular dark field imaging complemented with ion-track molecular dynamics simulations show that the atoms in the ring structure are disordered, and have relatively larger cation-cation interspacing than in the bulk pyrochlore, illustrating the presence of tensile strain in the ring region. Density functional theory calculations show that the non-equilibrium defect-fluorite structure can be stabilized by tensile strain. The pyrochlore to defect-fluorite structure transformation in the ring region is predicted to be induced by recrystallization during a melt-quench process and stabilized by tensile strain. Static pair-potential calculations show that planar tensile strain lowers oxygen vacancy migration barriers in pyrochlores, in agreement with recent studies on fluorite and perovskite materials. In view of these results, it is suggested that strain engineering could be simultaneously used to stabilize the defect-fluorite structure and gain control over its high ion-conducting properties. PMID:26555848

  14. Fast ion conductivity in strained defect-fluorite structure created by ion tracks in Gd2Ti2O7.

    PubMed

    Aidhy, Dilpuneet S; Sachan, Ritesh; Zarkadoula, Eva; Pakarinen, Olli; Chisholm, Matthew F; Zhang, Yanwen; Weber, William J

    2015-11-10

    The structure and ion-conducting properties of the defect-fluorite ring structure formed around amorphous ion-tracks by swift heavy ion irradiation of Gd2Ti2O7 pyrochlore are investigated. High angle annular dark field imaging complemented with ion-track molecular dynamics simulations show that the atoms in the ring structure are disordered, and have relatively larger cation-cation interspacing than in the bulk pyrochlore, illustrating the presence of tensile strain in the ring region. Density functional theory calculations show that the non-equilibrium defect-fluorite structure can be stabilized by tensile strain. The pyrochlore to defect-fluorite structure transformation in the ring region is predicted to be induced by recrystallization during a melt-quench process and stabilized by tensile strain. Static pair-potential calculations show that planar tensile strain lowers oxygen vacancy migration barriers in pyrochlores, in agreement with recent studies on fluorite and perovskite materials. In view of these results, it is suggested that strain engineering could be simultaneously used to stabilize the defect-fluorite structure and gain control over its high ion-conducting properties.

  15. Fast ion conductivity in strained defect-fluorite structure created by ion tracks in Gd2Ti2O7

    DOE PAGES

    Aidhy, Dilpuneet S.; Sachan, Ritesh; Zarkadoula, Eva; ...

    2015-11-10

    The structure and ion-conducting properties of the defect-fluorite ring structure formed around amorphous ion-tracks by swift heavy ion irradiation of Gd2Ti2O7 pyrochlore are investigated. High angle annular dark field imaging complemented with ion-track molecular dynamics simulations show that the atoms in the ring structure are disordered, and have relatively larger cation-cation interspacing than in the bulk pyrochlore, illustrating the presence of tensile strain in the ring region. Density functional theory calculations show that the non-equilibrium defect-fluorite structure can be stabilized by tensile strain. The pyrochlore to defect-fluorite structure transformation in the ring region is predicted to be induced by recrystallizationmore » during a melt-quench process and stabilized by tensile strain. Static pair-potential calculations show that planar tensile strain lowers oxygen vacancy migration barriers in pyrochlores, in agreement with recent studies on fluorite and perovskite materials. Lastly, in view of these results, it is suggested that strain engineering could be simultaneously used to stabilize the defect-fluorite structure and gain control over its high ion-conducting properties.« less

  16. New Fast Fall Detection Method Based on Spatio-Temporal Context Tracking of Head by Using Depth Images

    PubMed Central

    Yang, Lei; Ren, Yanyun; Hu, Huosheng; Tian, Bo

    2015-01-01

    In order to deal with the problem of projection occurring in fall detection with two-dimensional (2D) grey or color images, this paper proposed a robust fall detection method based on spatio-temporal context tracking over three-dimensional (3D) depth images that are captured by the Kinect sensor. In the pre-processing procedure, the parameters of the Single-Gauss-Model (SGM) are estimated and the coefficients of the floor plane equation are extracted from the background images. Once human subject appears in the scene, the silhouette is extracted by SGM and the foreground coefficient of ellipses is used to determine the head position. The dense spatio-temporal context (STC) algorithm is then applied to track the head position and the distance from the head to floor plane is calculated in every following frame of the depth image. When the distance is lower than an adaptive threshold, the centroid height of the human will be used as the second judgment criteria to decide whether a fall incident happened. Lastly, four groups of experiments with different falling directions are performed. Experimental results show that the proposed method can detect fall incidents that occurred in different orientations, and they only need a low computation complexity. PMID:26378540

  17. Wave - fluid particle interaction in the Faraday waves

    NASA Astrophysics Data System (ADS)

    Francois, Nicolas; Xia, Hua; Punzmann, Horst; Shats, Michael

    2016-11-01

    Faraday waves are parametrically excited perturbations that appear on a liquid surface when the latter is vertically vibrated. Recently it has been discovered that: 1) such wave field can be described as a disordered lattice made of localised oscillating excitations, termed oscillons, 2) the horizontal motion of fluid particles on the water surface reproduces in detail the motion of fluid in two-dimensional turbulence. Here we report experimental measurements of the motion of both entities using Particle Image Velocimetry and Particle Tracking Velocimetry techniques. Those techniques allow to measure Lagrangian and Eulerian features of the oscillon motion and compare them with those of the fluid motion. A strong coupling is uncovered between the erratic motion of the waves and the turbulent agitation of the fluid particles. Both motions show Brownian-type dispersion and the r.m.s velocity of oscillons is directly related to the r.m.s. velocity of the fluid particles in a broad range of vertical accelerations. These results offer new perspectives for predicting surface fluid transport from the knowledge of the wave fields and vice versa. In particular, the broadening of the wave spectra at high wave amplitude can be predicted if the 2D turbulence energy is known. This work was supported by the Australian Research Council's Discovery Projects funding scheme (DP150103468 and DP160100863). NF acknowledges support by the Australian Research Council's DECRA Award (DE160100742).

  18. Midplane Faraday rotation: A tokamak densitometer

    NASA Astrophysics Data System (ADS)

    Jobes, F. C.

    1995-01-01

    The density in a tokamak can be determined by measuring the Faraday rotation of a laser directed tangent to the toroidal field. If there is a horizontal array of such beams, then ne(R) can be readily obtained with a simple Abel inversion about the center line of the tokamak. For a large machine, such as ITER, TPX, or JT-60, a 10.6 μm laser would be appropriate. If the machine operated at a full field of 10-50 T m and a peak density of 2.5×1020/m3, the rotation angle would be quite large—about 15°-75° per pass. An elegant measurement system can be made up from a single laser beam diffracted off a moving grating to form a fan of ˜10 probe beams. With the addition of a few optical components to the system, the return beams can be recombined and sent to a single detector. In the detector there is a separate frequency component for both the right and left hand component of each ray. These can be separated electronically to provide a reference and probe signal for each ray; the difference in phase between the two signals is twice the Faraday rotation angle.

  19. Faraday diagnostics for R-damage

    SciTech Connect

    Oro, David M; Tabaka, Leonard J

    2011-01-13

    ALT-3 and R-Damage are experiments to be executed in collaboration between LANL and VNIIEF personnel. They are planned to be fielded in Sarov, Russia at VNIIEF. Both experiments employ Russian explosively driven pulse-power systems to generate a pulse of electrical current that is used to drive the experiment. The current pulse will be measured with Faraday-rotation fiber-optic loops. Using this well known technique, the change in the current enclosed by the loops is determined by measuring the change in the magnetic field integrated along the fiber-optic loop by detecting the Faraday rotation of linearly polarized light traveling through the fiber. The amount of polarization rotation of the light is related to the integrated magnetic field and therefore the enclosed current (Ampere's law) through the Verdet constant which for the optical-fibers used in this experiment has been determined to within 1 %. The presentation describes how the technique will be employed in the R-Damage experiment.

  20. Correcting ionospheric Faraday rotation for ASKAP

    NASA Astrophysics Data System (ADS)

    O'Sullivan, Shane; Gaensler, Bryan; Landecker, Tom L.; Willis, Tony

    2012-10-01

    Next-generation polarisation surveys, such as the POSSUM survey on ASKAP, aim to measure weak, statistical, cosmological effects associated with weak magnetic fields, and so will require unprecedented accuracy and stability for measuring polarisation vectors and their Faraday rotation measures (RMs). Ionospheric Faraday rotation (IFR) corrupts polarization observations and cannot be ignored at mid to low frequencies. In aperture-synthesis polarimetry IFR rotates individual visibilities and leads to a loss of coherence and accuracy of polarization angle determination. Through the POSSUM survey science team we have been involved in developing detailed ionospheric prediction software (POSSUM memos #10a,b) that will be used to correct the observed visibilities on ASKAP before imaging to obtain sufficiently accurate polarization and RM data. To provide a stringent test of this software, we propose a continuous 24 hr observing block using the 1.1-3.1 GHz band to monitor the variations caused by the time-variable ionosphere in the polarization angle and RM of a strongly polarized calibrator source, PKS B1903-802. We request a total of 96 hrs (4 x 24 hrs) to monitor the changes in the ionosphere every 3 to 6 months until BETA/ASKAP-12 is taking reliable polarization data.

  1. Analytical balance-based Faraday magnetometer

    NASA Astrophysics Data System (ADS)

    Riminucci, Alberto; Uhlarz, Marc; De Santis, Roberto; Herrmannsdörfer, Thomas

    2017-03-01

    We introduce a Faraday magnetometer based on an analytical balance in which we were able to apply magnetic fields up to 0.14 T. We calibrated it with a 1 mm Ni sphere previously characterized in a superconducting quantum interference device (SQUID) magnetometer. The proposed magnetometer reached a theoretical sensitivity of 3 × 10-8 A m2. We demonstrated its operation on magnetic composite scaffolds made of poly(ɛ-caprolactone)/iron-doped hydroxyapatite. To confirm the validity of the method, we measured the same scaffold properties in a SQUID magnetometer. The agreement between the two measurements was within 5% at 0.127 T and 12% at 24 mT. With the addition, for a small cost, of a permanent magnet and computer controlled linear translators, we were thus able to assemble a Faraday magnetometer based on an analytical balance, which is a virtually ubiquitous instrument. This will make simple but effective magnetometry easily accessible to most laboratories, in particular, to life sciences ones, which are increasingly interested in magnetic materials.

  2. Micro-position sensor using faraday effect

    SciTech Connect

    McElfresh, Michael; Lucas, Matthew; Silveira, Joseph P.; Groves, Scott E.

    2007-02-27

    A micro-position sensor and sensing system using the Faraday Effect. The sensor uses a permanent magnet to provide a magnetic field, and a magneto-optic material positioned in the magnetic field for rotating the plane of polarization of polarized light transmitted through the magneto-optic material. The magnet is independently movable relative to the magneto-optic material so as to rotate the plane of polarization of the polarized light as a function of the relative position of the magnet. In this manner, the position of the magnet relative to the magneto-optic material may be determined from the rotated polarized light. The sensing system also includes a light source, such as a laser or LED, for producing polarized light, and an optical fiber which is connected to the light source and to the magneto-optic material at a sensing end of the optical fiber. Processing electronics, such as a polarimeter, are also provided for determining the Faraday rotation of the plane of polarization of the back-reflected polarized light to determine the position of the magnet relative to the sensing end of the optical fiber.

  3. Faraday rotation measure synthesis of UGC 10288

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    Faraday rotation measure synthesis is a powerful tool that has been employed in the past decade when studying line-of-sight magnetic fields of galactic and extragalactic sources. Rotation measures, which are sensitive to the strength and direction of fields in an intervening medium between the source and observer, were classically determined by assuming a single, uniform Faraday-rotating medium. Rotation measure synthesis, on the other hand, is a more robust method that allows for probing a more complicated scenario. We will outline results from a study of magnetic field structure in the disk and halo of edge-on galaxy UGC 10288, using 6 cm and 20 cm observations from CHANG-ES (Continuum Halos in Nearby Galaxies - an EVLA Survey). The presence of a strongly polarized complex background source situated perpendicular to the foreground disk allows for an investigation of the disk-halo magnetic fields of UGC 10288. In particular, we present evidence of magnetic field reversals above the plane of the disk. This finding is not easily explained solely by the prevailing α-Ω dynamo mechanism. Rather, a field reversal may be indicative of different parities of the poloidal field components for the individual disk and halo mechanisms.

  4. Faraday waves, streaming flow, and relaxation oscillations in nearly circular containers.

    PubMed

    Higuera, M; Porter, J; Knobloch, E

    2008-03-01

    Faraday waves near onset in an elliptical container are described by a third-order system of ordinary differential equations with characteristic slow-fast structure. These equations describe the interaction of standing waves with a weakly damped streaming flow driven by Reynolds stresses in boundary layers at the free surface and the rigid walls, and capture the proliferation with decreasing damping of periodic and nonperiodic relaxation oscillations observed near onset in previous simulations. These structures are the result of slow drift through symmetry-related Hopf bifurcations.

  5. The Interactions between Global Education Initiatives and National Education Policy and Planning Processes: A Comparative Case Study of the Education For All Fast Track Initiative in Rwanda and Ethiopia. CREATE Pathways to Access. Research Monograph No. 67

    ERIC Educational Resources Information Center

    Bermingham, Desmond

    2011-01-01

    The Education for All Fast Track Initiative (FTI) was launched by the World Bank in 2002 as a global initiative to help low income countries accelerate progress towards the MDG target of universal primary education by 2015. Over the past decade, the FTI has expanded to become one of the most important initiatives to emerge out of the Dakar World…

  6. Faraday effect in Sn2P2S6 crystals.

    PubMed

    Krupych, Oleh; Adamenko, Dmytro; Mys, Oksana; Grabar, Aleksandr; Vlokh, Rostyslav

    2008-11-10

    We have revealed a large Faraday rotation in tin thiohypodiphosphate (Sn(2)P(2)S(6)) crystals, which makes this material promising for magneto-optics. The effective Faraday tensor component and the Verdet constant for the direction of the optic axis have been determined by measuring the pure Faraday rotation in Sn(2)P(2)S(6) crystals with both the single-ray and small-angular polarimetric methods at the normal conditions and a wavelength of 632.8 nm. The effective Verdet constant is found to be equal to 115 rad/T x m.

  7. Miniature modified Faraday cup for micro electron beams

    DOEpatents

    Teruya, Alan T.; Elmer, John W.; Palmer, Todd A.; Walton, Chris C.

    2008-05-27

    A micro beam Faraday cup assembly includes a refractory metal layer with an odd number of thin, radially positioned traces in this refractory metal layer. Some of the radially positioned traces are located at the edge of the micro modified Faraday cup body and some of the radially positioned traces are located in the central portion of the micro modified Faraday cup body. Each set of traces is connected to a separate data acquisition channel to form multiple independent diagnostic networks. The data obtained from the two diagnostic networks are combined and inputted into a computed tomography algorithm to reconstruct the beam shape, size, and power density distribution.

  8. Current measurement by Faraday effect on GEPOPU

    NASA Astrophysics Data System (ADS)

    N, Correa; H, Chuaqui; E, Wyndham; F, Veloso; J, Valenzuela; M, Favre; H, Bhuyan

    2014-05-01

    The design and calibration of an optical current sensor using BK7 glass is presented. The current sensor is based on the polarization rotation by Faraday effect. GEPOPU is a pulsed power generator, double transit time 120ns, 1.5 Ohm impedance, coaxial geometry, where Z pinch experiment are performed. The measurements were performed at the Optics and Plasma Physics Laboratory of Pontificia Universidad Catolica de Chile. The verdet constant for two different optical materials was obtained using He-Ne laser. The values obtained are within the experimental error bars of measurements published in the literature (less than 15% difference). Two different sensor geometries were tried. We present the preliminary results for one of the geometries. The values obtained for the current agree within the measurement error with those obtained by means of a Spice simulation of the generator. Signal traces obtained are completely noise free.

  9. Line-of-sight kinematics and corrections for fast-steering mirrors used in precision pointing and tracking systems

    NASA Astrophysics Data System (ADS)

    Hilkert, J. M.; Kanga, Gavin; Kinnear, K.

    2014-06-01

    Fast steering mirrors, or FSMs, have been used for several decades to enhance or augment the performance of electrooptical imaging and beam-steering systems in applications such as astronomy, laser communications and military targeting and surveillance systems. FSMs are high-precision, high-bandwidth electro-mechanical mechanisms used to deflect a mirror over a small angular displacement relative to the base it is mounted on which is typically a stabilized gimbal or other primary pointing device. Although the equations describing the line-of-sight kinematics derive entirely from the simple plane-mirror law of reflection, they are non-linear and axis-coupled and these effects increase as the FSM angular displacement increases. These inherent non-linearities and axis-coupling effects can contribute to pointing errors in certain modes of operation. The relevant kinematic equations presented in this paper can be used to assess the magnitude of the errors for a given application and make corrections as necessary.

  10. Tracking the time course of action priming on object recognition: evidence for fast and slow influences of action on perception.

    PubMed

    Kiefer, Markus; Sim, Eun-Jin; Helbig, Hannah; Graf, Markus

    2011-08-01

    Perception and action are classically thought to be supported by functionally and neuroanatomically distinct mechanisms. However, recent behavioral studies using an action priming paradigm challenged this view and showed that action representations can facilitate object recognition. This study determined whether action representations influence object recognition during early visual processing stages, that is, within the first 150 msec. To this end, the time course of brain activation underlying such action priming effects was examined by recording ERPs. Subjects were sequentially presented with two manipulable objects (e.g., tools), which had to be named. In the congruent condition, both objects afforded similar actions, whereas dissimilar actions were afforded in the incongruent condition. In order to test the influence of the prime modality on action priming, the first object (prime) was presented either as picture or as word. We found an ERP effect of action priming over the central scalp as early as 100 msec after target onset for pictorial, but not for verbal primes. A later action priming effect on the N400 ERP component known to index semantic integration processes was obtained for both picture and word primes. The early effect was generated in a fronto-parietal motor network, whereas the late effect reflected activity in anterior temporal areas. The present results indicate that action priming influences object recognition through both fast and slow pathways: Action priming affects rapid visuomotor processes only when elicited by pictorial prime stimuli. However, it also modulates comparably slow conceptual integration processes independent of the prime modality.

  11. Faraday effect based optical fiber current sensor for tokamaks

    SciTech Connect

    Aerssens, M.; Gusarov, A.; Brichard, B.; Massaut, V.; Megret, P.; Wuilpart, M.

    2011-07-01

    Fiber optical current sensor (FOCS) is a technique considered to be compatible with the ITER nuclear environment. FOCS principle is based on the magneto-optic Faraday effect that produces non-reciprocal circular birefringence when a magnetic field is applied in the propagation direction of the light beam. The magnetic field or the electrical current is deduced from the modification of the state of polarization of light. The linear birefringence of the fiber related with non-perfect manufacturing, temperature changes or stress constitute a parasitic effect that reduces the precision and sensitivity of FOCS. A two-pass optical scheme with a Faraday mirror at the end has been proposed to compensate the influence of linear birefringence. In this paper we perform a Stokes analysis of the two-pass optical scheme to highlight the fact that the linear birefringence is not compensated perfectly by the Faraday mirror when non-reciprocal birefringence such as Faraday effect is also present. (authors)

  12. The Faraday effect of natural and artificial ferritins

    NASA Astrophysics Data System (ADS)

    Koralewski, M.; Kłos, J. W.; Baranowski, M.; Mitróová, Z.; Kopčanský, P.; Melníková, L.; Okuda, M.; Schwarzacher, W.

    2012-09-01

    Measurements of the Faraday rotation at room temperature over the light wavelength range of 300-680 nm for horse spleen ferritin (HSF), magnetoferritin with different loading factors (LFs) and nanoscale magnetite and Fe2O3 suspensions are reported. The Faraday rotation and the magnetization of the materials studied present similar magnetic field dependences and are characteristic of a superparamagnetic system. The dependence of the Faraday rotation on the magnetic field is described, excluding HSF and Fe2O3, by a Langevin function with a log-normal distribution of the particle size allowing the core diameters of the substances studied to be calculated. It was found that the specific Verdet constant depends linearly on the LF. Differences in the Faraday rotation spectra and their magnetic field dependences allow discrimination between magnetoferritin with maghemite and magnetite cores which can be very useful in biomedicine.

  13. Faraday effect in hybrid magneto-plasmonic photonic crystals.

    PubMed

    Caballero, B; García-Martín, A; Cuevas, J C

    2015-08-24

    We present a theoretical study of the Faraday effect in hybrid magneto-plasmonic crystals that consist of Au-Co-Au perforated membranes with a periodic array of sub-wavelength holes. We show that in these hybrid systems the interplay between the extraordinary optical transmission and the magneto-optical activity leads to a resonant enhancement of the Faraday rotation, as compared to purely ferromagnetic membranes. In particular, we determine the geometrical parameters for which this enhancement is optimized and show that the inclusion of a noble metal like Au dramatically increases the Faraday rotation over a broad bandwidth. Moreover, we show that the analysis of the Faraday rotation in these periodically perforated membranes provides a further insight into the origin of the extraordinary optical transmission.

  14. The Faraday effect of natural and artificial ferritins.

    PubMed

    Koralewski, M; Kłos, J W; Baranowski, M; Mitróová, Z; Kopčanský, P; Melníková, L; Okuda, M; Schwarzacher, W

    2012-09-07

    Measurements of the Faraday rotation at room temperature over the light wavelength range of 300-680 nm for horse spleen ferritin (HSF), magnetoferritin with different loading factors (LFs) and nanoscale magnetite and Fe(2)O(3) suspensions are reported. The Faraday rotation and the magnetization of the materials studied present similar magnetic field dependences and are characteristic of a superparamagnetic system. The dependence of the Faraday rotation on the magnetic field is described, excluding HSF and Fe(2)O(3), by a Langevin function with a log-normal distribution of the particle size allowing the core diameters of the substances studied to be calculated. It was found that the specific Verdet constant depends linearly on the LF. Differences in the Faraday rotation spectra and their magnetic field dependences allow discrimination between magnetoferritin with maghemite and magnetite cores which can be very useful in biomedicine.

  15. One-Piece Faraday Generator: A Paradoxical Experiment from 1851

    ERIC Educational Resources Information Center

    Crooks, M. J.; And Others

    1978-01-01

    Describes an experiment based on Faraday's one-piece generator, where the rotating disk is replaced by a cylindrical permanent magnet. Explains the apparent paradox that an observer in an inertial frame could measure his absolute velocity. (GA)

  16. Vibration immunity for a triangular Faraday current sensor

    NASA Astrophysics Data System (ADS)

    Fisher, Norman E.; Jackson, David A.

    1996-10-01

    We demonstrate a common-mode rejection scheme for a bulk- optic triangular Faraday current sensor that can eliminate optical noise induced by fiber-link vibration. The noise floor before applying common rejection was about 30 dB for a 100A Faraday signal and transceiver vibration levels of approximately 30 g. This was reduced to about 60 dB for the same vibration levels. The sensor's exploitation of Ampere's circuital law is also demonstrated.

  17. Faraday rotation due to excitation of magnetoplasmons in graphene microribbons.

    PubMed

    Tymchenko, Mykhailo; Nikitin, Alexey Yu; Martín-Moreno, Luis

    2013-11-26

    A single graphene sheet, when subjected to a perpendicular static magnetic field, provides a Faraday rotation that, per atomic layer, greatly surpasses that of any other known material. In continuous graphene, Faraday rotation originates from the cyclotron resonance of massless carriers, which allows dynamical tuning through either external electrostatic or magneto-static setting. Furthermore, the rotation direction can be controlled by changing the sign of the carriers in graphene, which can be done by means of an external electric field. However, despite these tuning possibilities, the requirement of large magnetic fields hinders the application of the Faraday effect in real devices, especially for frequencies higher than a few terahertz. In this work we demonstrate that large Faraday rotation can be achieved in arrays of graphene microribbons, through the excitation of the magnetoplasmons of individual ribbons, at larger frequencies than those dictated by the cyclotron resonance. In this way, for a given magnetic field and chemical potential, structuring graphene periodically can produce large Faraday rotation at larger frequencies than what would occur in a continuous graphene sheet. Alternatively, at a given frequency, graphene ribbons produce large Faraday rotation at much smaller magnetic fields than in continuous graphene.

  18. The fast track to canonical Wnt signaling in MC3T3-E1 cells protected by substance P against serum deprivation-induced apoptosis.

    PubMed

    Yang, Jianguo; Nie, Jiping; Fu, Su; Liu, Song; Wu, Jianqun; Cui, Liang; Zhang, Yongtao; Yu, Bin

    2017-01-01

    The canonical Wnt pathway is vital to bone physiology by increasing bone mass through elevated osteoblast survival. Although investigated extensively in stem cells, its role in osteoblastic MC3T3-E1 cells has not been completely determined. To explore how this pathway is regulated by different conditions, we assessed the anti-apoptotic effects of substance P on the canonical Wnt pathway in MC3T3-E1 cells by treating cells with serum deprivation or serum starving with "substance P," a neuropeptide demonstrated to promote bone growth and stimulate Wnt signaling. The results showed that serum deprivation both induced apoptosis and activated Wnt signal transduction while substance P further stimulated the Wnt pathway via the NK-1 receptor but protected the cells from apoptotic death. Fast-tracking of Wnt signaling by substance P was also noted. These results indicate that nutritional deprivation and substance P synergistically activated the canonical Wnt pathway, a finding that helps to reveal the role of Wnt signaling in bone physiology affected by nutritional deprivation and neuropeptide substance P.

  19. Relationship between self-reported pain sensitivity and pain after total knee arthroplasty: a prospective study of 71 patients 8 weeks after a standardized fast-track program

    PubMed Central

    Valeberg, Berit T; Høvik, Lise H; Gjeilo, Kari H

    2016-01-01

    Background and purpose This was a prospective cohort study assessing data from 71 adult patients undergoing total knee arthroplasty (TKA) following a standardized fast-track program between January and July 2013. The objective was to examine the relationship between self-rated pain sensitivity, as measured by the Pain Sensitivity Questionnaire (PSQ), and postoperative pain after TKA. Methods The baseline questionnaires, PSQ and Brief Pain Inventory, were given to the patients for self-administration at the presurgical evaluation (1–2 weeks prior to surgery). The follow-up questionnaire, Brief Pain Inventory, was administered at the first follow-up, 8 weeks after surgery. Results A statistically significant association was found between average preoperative pain and average pain 8 weeks after surgery (P=0.001). The PSQ-minor was statistically significantly associated with average pain only for patients younger than 70 years (P=0.03). Interpretation This is the first study to examine the relationship between pain sensitivity measured by PSQ and postoperative pain in patients after TKA. We found that a lower score on the PSQ-minor was statistically significantly associated with patients’ pain 8 weeks after TKA surgery, but only for younger patients. Further research is needed to explore whether the PSQ could be a useful screening tool for patients’ pain sensitivity in clinical settings. PMID:27660489

  20. Testing Ionospheric Faraday Rotation Corrections in CASA

    NASA Astrophysics Data System (ADS)

    Kooi, Jason E.; Moellenbrock, George

    2015-04-01

    The Earth’s ionosphere introduces direction- and time-dependent effects over a range of physical and temporal scales and so is a major source for unmodeled phase offsets for low frequency radioastronomical observations. Ionospheric effects are often the limiting factor to making sensitive radioastronomical measurements to probe the solar corona or coronal mass ejections at low frequencies (< 5 GHz). It has become common practice to use global ionospheric models derived from the Global Positioning System (GPS) to provide a means of externally calibrating low frequency data. We have developed a new calibration algorithm in the Common Astronomy Software Applications (CASA) package. CASA, which was developed to meet the data post-processing needs of next generation telescopes such as the Karl G. Jansky Very Large Array (VLA), did not previously have the capability to mitigate ionospheric effects. This algorithm uses GPS-based global ionosphere maps to mitigate the first and second order ionospheric effects (dispersion delay and Faraday rotation, respectively). We investigated several data centers as potential sources for global ionospheric models and chose the International Global Navigation Satellite System Service data product because data from other sources are generally too sparse to use without additional interpolation schemes. This implementation of ionospheric corrections in CASA has been tested on several sets of VLA observations and all of them showed a significant reduction of the dispersion delay. In order to rigorously test CASA’s ability to mitigate ionospheric Faraday rotation, we made VLA full-polarization observations of the standard VLA phase calibrators J0359+5057 and J0423+4150 in August 2014, using L band (1 - 2 GHz), S band (2 - 4 GHz), and C band (4 - 6 GHz) frequencies in the D array configuration. The observations were 4 hours in duration, beginning near local sunrise. In this paper, we give a general description of how these corrections are

  1. Fluctuation dynamos and their Faraday rotation signatures

    NASA Astrophysics Data System (ADS)

    Bhat, Pallavi; Subramanian, Kandaswamy

    2013-03-01

    Turbulence is ubiquitous in many astrophysical systems like galaxies, galaxy clusters and possibly even the filaments in the intergalactic medium. We study fluctuation dynamo action in turbulent systems focusing on one observational signature, the random Faraday rotation measure (RM) from radio emission of background sources seen through the intermittent magnetic field generated by such a dynamo. We simulate the fluctuation dynamo in periodic boxes up to resolutions of 5123, with varying fluid and magnetic Reynolds numbers, and measure the resulting random RMs. We show that even though the magnetic field generated is intermittent, it still allows for contributions to the RM to be significant. When the dynamo saturates, the rms value of RM is of the order of 40-50 per cent of the value expected in a model where fields of strength Brms uniformly fill cells of the largest turbulent eddy but are randomly oriented from one cell to another. This level of RM dispersion is obtained across different values of magnetic Reynolds number and Prandtl number explored. We also use the random RMs to probe the structure of the generated fields to distinguish the contribution from intense and diffuse field regions. We find that the strong field regions (say with B > 2Brms) contribute only of the order of 15-20 per cent to the RM. Thus, rare structures do not dominate the RM; rather, the general `sea' of volume filling fluctuating fields are the dominant contributors. We also show that the magnetic integral scale, Lint, which is directly related to the RM dispersion, increases in all the runs, as Lorentz forces become important to saturate the dynamo. It appears that due to the ordering effect of the Lorentz forces, Lint of the saturated field tends to a modest fraction, 1/2-1/3 of the integral scale of the velocity field, for all our runs. These results are then applied to discuss the Faraday rotation signatures of fluctuation dynamo generated fields in young galaxies, galaxy

  2. Resonant inverse Faraday effect in nanorings

    NASA Astrophysics Data System (ADS)

    Koshelev, K. L.; Kachorovskii, V. Yu.; Titov, M.

    2015-12-01

    A circularly polarized light can induce a dissipationless dc current in a quantum nanoring which is responsible for a resonant helicity-driven contribution to magnetic moment. This current is not suppressed by thermal averaging despite its quantum nature. We refer to this phenomenon as the quantum resonant inverse Faraday effect. For weak electromagnetic field, when the characteristic coupling energy is small compared to the energy level spacing, we predict narrow resonances in the circulating current and, consequently, in the magnetic moment of the ring. For strong fields, the resonances merge into a wide peak with a width determined by the spectral curvature. We further demonstrate that weak short-range disorder splits the resonances and induces additional particularly sharp and high resonant peaks in dc current and magnetization. In contrast, long-range disorder leads to a chaotic behavior of the system in the vicinity of the separatrix that divides the phase space of the system into regions with dynamically localized and delocalized states.

  3. Linear diffusion into a Faraday cage.

    SciTech Connect

    Warne, Larry Kevin; Lin, Yau Tang; Merewether, Kimball O.; Chen, Kenneth C.

    2011-11-01

    Linear lightning diffusion into a Faraday cage is studied. An early-time integral valid for large ratios of enclosure size to enclosure thickness and small relative permeability ({mu}/{mu}{sub 0} {le} 10) is used for this study. Existing solutions for nearby lightning impulse responses of electrically thick-wall enclosures are refined and extended to calculate the nearby lightning magnetic field (H) and time-derivative magnetic field (HDOT) inside enclosures of varying thickness caused by a decaying exponential excitation. For a direct strike scenario, the early-time integral for a worst-case line source outside the enclosure caused by an impulse is simplified and numerically integrated to give the interior H and HDOT at the location closest to the source as well as a function of distance from the source. H and HDOT enclosure response functions for decaying exponentials are considered for an enclosure wall of any thickness. Simple formulas are derived to provide a description of enclosure interior H and HDOT as well. Direct strike voltage and current bounds for a single-turn optimally-coupled loop for all three waveforms are also given.

  4. 1/f Noise Inside a Faraday Cage

    SciTech Connect

    Handel, Peter H.; George, Thomas F.

    2009-04-23

    We show that quantum 1/f noise does not have a lower frequency limit given by the lowest free electromagnetic field mode in a Faraday cage, even in an ideal cage. Indeed, quantum 1/f noise comes from the infrared-divergent coupling of the field with the charges, in their joint nonlinear system, where the charges cause the field that reacts back on the charges, and so on. This low-frequency limitation is thus not applicable for the nonlinear system of matter and field in interaction. Indeed, this nonlinear system is governed by Newton's laws, Maxwell's equations, in general also by the diffusion equations for particles and heat, or reaction kinetics given by quantum matrix elements. Nevertheless, all the other quantities can be eliminated in principle, resulting in highly nonlinear integro-differential equations for the electromagnetic field only, which no longer yield a fundamental frequency. Alternatively, we may describe this through the presence of an infinite system of subharmonics. We show how this was proven early in the classical and quantum domains, adding new insight.

  5. 1/f Noise Inside a Faraday Cage

    NASA Astrophysics Data System (ADS)

    Handel, Peter H.; George, Thomas F.

    2009-04-01

    We show that quantum 1/f noise does not have a lower frequency limit given by the lowest free electromagnetic field mode in a Faraday cage, even in an ideal cage. Indeed, quantum 1/f noise comes from the infrared-divergent coupling of the field with the charges, in their joint nonlinear system, where the charges cause the field that reacts back on the charges, and so on. This low-frequency limitation is thus not applicable for the nonlinear system of matter and field in interaction. Indeed, this nonlinear system is governed by Newton's laws, Maxwell's equations, in general also by the diffusion equations for particles and heat, or reaction kinetics given by quantum matrix elements. Nevertheless, all the other quantities can be eliminated in principle, resulting in highly nonlinear integro-differential equations for the electromagnetic field only, which no longer yield a fundamental frequency. Alternatively, we may describe this through the presence of an infinite system of subharmonics. We show how this was proven early in the classical and quantum domains, adding new insight.

  6. Multifrequency control of Faraday wave patterns.

    PubMed

    Topaz, Chad M; Porter, Jeff; Silber, Mary

    2004-12-01

    We show how pattern formation in Faraday waves may be manipulated by varying the harmonic content of the periodic forcing function. Our approach relies on the crucial influence of resonant triad interactions coupling pairs of critical standing wave modes with damped, spatiotemporally resonant modes. Under the assumption of weak damping and forcing, we perform a symmetry-based analysis that reveals the damped modes most relevant for pattern selection, and how the strength of the corresponding triad interactions depends on the forcing frequencies, amplitudes, and phases. In many cases, the further assumption of Hamiltonian structure in the inviscid limit determines whether the given triad interaction has an enhancing or suppressing effect on related patterns. Surprisingly, even for forcing functions with arbitrarily many frequency components, there are at most five frequencies that affect each of the important triad interactions at leading order. The relative phases of those forcing components play a key role, sometimes making the difference between an enhancing and suppressing effect. In numerical examples, we examine the validity of our results for larger values of the damping and forcing. Finally, we apply our findings to one-dimensional periodic patterns obtained with impulsive forcing and to two-dimensional superlattice patterns and quasipatterns obtained with multifrequency forcing.

  7. Thromboembolic and major bleeding events in relation to perioperative bridging of vitamin K antagonists in 649 fast-track total hip and knee arthroplasties

    PubMed Central

    Jørgensen, Christoffer C; Kehlet, Henrik

    2017-01-01

    Background — The benefit of preoperative bridging in surgical patients with continuous anticoagulant therapy is debatable, and drawing of meaningful conclusions may have been limited by mixed procedures with different thromboembolic and bleeding risks in most published studies. Patients and methods — This was an observational cohort treatment study in consecutive primary unilateral total hip and knee arthroplasty patients between January 2010 and November 2013 in 8 Danish fast-track departments. Data were collected prospectively on preoperative comorbidity and anticoagulants in patients with preoperative vitamin K antagonist (VKA) treatment. We performed 30-day follow-up on in-hospital complications and re-admissions through the Danish National Patient Registry and patient records. Results — Of 13,375 procedures, 649 (4.7%) were in VKA patients with a mean age of 73 (SD 9) years and a median length of stay of 3 days (IQR: 2–4). Preoperative bridging was used in 430 (67%), while 215 (33%) were paused. Of 4 arterial thromboembolic events (ATEs) (0.6%), 2 were in paused patients and 2 were in bridged patients (p = 0.6). Of 3 venous thromboembolic events (VTEs) (0.5%), 2 were in paused patients and 1 was in a bridged patient (p = 0.3). Of 8 major bleedings (MBs) (1.2%), 1 was in a paused patient and 7 were in bridged patients (p = 0.3), 5 of whom received therapeutic bridging. Similar results were found in a propensity-matched cohort. Interpretation — In contrast to recent studies in mixed surgical procedures, no statistically significant differences in ATE, VTE, or MB were found between preoperative bridging and pausation of VKA patients. However, the higher number of thromboembolic events in paused patients and the higher number of major bleedings in bridged patients warrant more extensive investigation. PMID:27759465

  8. Anomalous Faraday rotation in the ISM/ICM

    NASA Astrophysics Data System (ADS)

    Medvedev, Mikhail V.

    2016-10-01

    Faraday effect is a common and useful way to deduce cosmic magnetic fields in the interstellar and intracluster media (ISM and ICM). Faraday rotation is the result of magnetically-induced birefringence in a dielectric medium causing a linearly polarized wave to suffer a rotation of its polarization axis as it traverses such a medium. However, the standard λ2-law of the rotation angle may not hold in strongly turbulent plasmas. Electromagnetic high-frequency and/or small-scale fluctuations may lead to effective collisionality with the pitch-angle diffusion coefficient being an effective ``quasi-collision'' frequency. Recently, we showed that quasi-collisionality may radically alter radiative transport properties of plasmas, such as absorption, transmission and reflection and other effects, which can be very important in laboratory and astrophysical plasmas. Here we briefly discuss the quasi-collisional generalization of the classical Faraday effect, which is drastically modified and can even become negative. Furthermore, we explore the origin of the long-known anomaly of Faraday rotation in a famous Cygnus regions. We argue that the anomaly can be due to the anomalous Faraday rotation in a thin ``blanket'' of turbulent plasma at the front of an interstellar bubble/shock. Supported by KU CLAS and DOE Grant ID0000225143 (07/01/16).

  9. Faraday instability in a near-critical fluid under weightlessness.

    PubMed

    Gandikota, G; Chatain, D; Amiroudine, S; Lyubimova, T; Beysens, D

    2014-01-01

    Experiments on near-critical hydrogen have been conducted under magnetic compensation of gravity to investigate the Faraday instability that arises at the liquid-vapor interface under zero-gravity conditions. We investigated such instability in the absence of stabilizing gravity. Under such conditions, vibration orients the interface and can destabilize it. The experiments confirm the existence of Faraday waves and demonstrate a transition from a square to a line pattern close to the critical point. They also show a transition very close to the critical point from Faraday to periodic layering of the vapor-liquid interface perpendicular to vibration. It was seen that the Faraday wave instability is favored when the liquid-vapor density difference is large enough (fluid far from the critical point), whereas periodic layering predominates for small difference in the liquid and vapor densities (close to the critical point). It was observed for the Faraday wave instability that the wavelength of the instability decreases as one approaches the critical point. The experimental results demonstrate good agreement to the dispersion relation for zero gravity except for temperatures very close to the critical point where a transition from a square pattern to a line pattern is detected, similarly to what is observed under 1g conditions.

  10. Laplace's equation and Faraday's lines of force

    SciTech Connect

    Narasimhan, T.N.

    2007-06-01

    Boundary-value problems involve two dependent variables: a potential function, and a stream function. They can be approached in two mutually independent ways. The first, introduced by Laplace, involves spatial gradients at a point. Inspired by Faraday, Maxwell introduced the other, visualizing the flow domain as a collection of flow tubes and isopotential surfaces. Boundary-value problems intrinsically entail coupled treatment (or, equivalently, optimization) of potential and stream functions Historically, potential theory avoided the cumbersome optimization task through ingenious techniques such as conformal mapping and Green's functions. Laplace's point-based approach, and Maxwell's global approach, each provides its own unique insights into boundary-value problems. Commonly, Laplace's equation is solved either algebraically, or with approximate numerical methods. Maxwell's geometry-based approach opens up novel possibilities of direct optimization, providing an independent logical basis for numerical models, rather than treating them as approximate solvers of the differential equation. Whereas points, gradients, and Darcy's law are central to posing problems on the basis of Laplace's approach, flow tubes, potential differences, and the mathematical form of Ohm's law are central to posing them in natural coordinates oriented along flow paths. Besides being of philosophical interest, optimization algorithms can provide advantages that complement the power of classical numerical models. In the spirit of Maxwell, who eloquently spoke for a balance between abstract mathematical symbolism and observable attributes of concrete objects, this paper is an examination of the central ideas of the two approaches, and a reflection on how Maxwell's integral visualization may be practically put to use in a world of digital computers.

  11. Multi-chord Faraday-Effect measurements of fluctuations in C-Mod

    NASA Astrophysics Data System (ADS)

    Bergerson, William; Xu, P.; Brower, D. L.; Ding, W. X.; Irby, J. H.

    2012-10-01

    Three chords measuring the Faraday effect are operated routinely across all machine conditions in C-mod and allow for internal measurements of the equilibrium poloidal magnetic field. Absolute error attributed to stray magnetic field effects is below 0.5 degree and noise related to contamination from the lower hybrid and ion cyclotron radio frequency systems are not observed. Tests indicate there is no measurable signal contamination from the toroidal magnetic field due to the Cotton-Mouton effect or misalignment. Polarization sensitivity of the wire mesh beamsplitters requires system calibration which is achieved using a rotating half-wave plate. Individual channels can be modified to measure the Cotton-Mouton effect directly and yield a line integrated density measurement without ``fringe skips.'' Fluctuations on the Faraday signal associated with sawteeth, tearing modes, the quasi-coherent mode, broadband turbulence, and fast particle driven modes are observed at frequencies up to 1 MHz. Efforts are underway to differentiate between density and magnetic fluctuations in the polarimetry measurement via cross correlation techniques and combined density measurements. This work supported by DOE contract DE-FG02-01ER54615 and DE-FC02-99ER54512-CMOD.

  12. Faraday-Effect Polarimeter-Interferometer System for current density measurement on EAST

    NASA Astrophysics Data System (ADS)

    Liu, Haiqing; Jie, Yinxian; Ding, Weixing; Brower, David Lyn; Zou, Zhiyong; Li, Weiming; Qian, Jinping; Yang, Yao; Zeng, Long; Lan, Ting; Li, Gongshun; Hu, Liqun; Wan, Baonian

    2014-10-01

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. System time response (~1 microsecond) and phase resolution (<0.1°) allows resolution of fast equilibrium changes associated with MHD events. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 1016 m-2 (~2°), and the Faraday rotation angle rms phase noise is <0.1°. Initial results of POINT system will be presented. This work is supported by the National Magnetic Confinement Fusion Program of China Contract No. 2012GB101002. This work is partly supported by the US D.O.E. Contract DESC0010469.

  13. Scientific Verification of Faraday Rotation Modulators: Detection of Diffuse Polarized Galactic Emission

    NASA Technical Reports Server (NTRS)

    Moyerman, S.; Bierman, E.; Ade, P. A. R.; Aiken, R.; Barkats, D.; Bischoff, C.; Bock, J. J.; Chiang, H. C.; Dowell, C. D.; Duband, L.; Hivon, E. F.; Holzapel, W. L.; Hristov, V. V.; Jones, W. C.; Kaufman, J.; Keating, B. G.; Kovac, J. M.; Kuo, C. L.; Leitch, E. M.; Mason, P. V.; Matsumura, T.; Nguyen, H. T.; Ponthieu, N.; Pryke, C.; Wollack, E.

    2012-01-01

    The design and performance of a wide bandwidth linear polarization-modulator based on the Faraday effect is described. Faraday Rotation Modulators (FRMs) are solid-state polarization switches that are capable of modulation up to approx 10 kHz. Six FRMs were utilized during the 2006 observing season in the Background Imaging of Cosmic Extragalactic Polarization (BICEP) experiment; three FRMs were used at each of BICEP fs 100 and 150 GHz frequency bands. The technology was verified through high signal-to-noise detection of Galactic polarization using two of the six FRMs during four observing runs in 2006. The features exhibit strong agreement with BICEP fs measurements of the Galaxy using non-FRM pixels and with the Galactic polarization models. This marks the first detection of high signal-to-noise mm-wave celestial polarization using fast, active optical modulation. The performance of the FRMs during periods when they were not modulated was also analyzed and compared to results from BICEP fs 43 pixels without FRMs.

  14. Versatile, high-sensitivity faraday cup array for ion implanters

    DOEpatents

    Musket, Ronald G.; Patterson, Robert G.

    2003-01-01

    An improved Faraday cup array for determining the dose of ions delivered to a substrate during ion implantation and for monitoring the uniformity of the dose delivered to the substrate. The improved Faraday cup array incorporates a variable size ion beam aperture by changing only an insertable plate that defines the aperture without changing the position of the Faraday cups which are positioned for the operation of the largest ion beam aperture. The design enables the dose sensitivity range, typically 10.sup.11 -10.sup.18 ions/cm.sup.2 to be extended to below 10.sup.6 ions/cm.sup.2. The insertable plate/aperture arrangement is structurally simple and enables scaling to aperture areas between <1 cm.sup.2 and >750 cm.sup.2, and enables ultra-high vacuum (UHV) applications by incorporation of UHV-compatible materials.

  15. Fabry-Perot enhanced Faraday rotation in graphene

    NASA Astrophysics Data System (ADS)

    Ubrig, Nicolas; Crassee, Iris; Levallois, Julien; Nedoliuk, Ievgeniia O.; Fromm, Felix; Kaiser, Michl; Seyller, Thomas; Kuzmenko, Alexey B.

    2013-10-01

    We demonstrate that giant Faraday rotation in graphene in the terahertz range due to the cyclotron resonance is further increased by constructive Fabry-Perot interference in the supporting substrate. Simultaneously, an enhanced total transmission is achieved, making this effect doubly advantageous for graphene-based magneto-optical applications. As an example, we present far-infrared spectra of epitaxial multilayer graphene grown on the C-face of 6H-SiC, where the interference fringes are spectrally resolved and a Faraday rotation up to 0.15 radians (9{\\deg}) is attained. Further, we discuss and compare other ways to increase the Faraday rotation using the principle of an optical cavity.

  16. Faraday tomography with LOFAR: new probe of the interstellar

    NASA Astrophysics Data System (ADS)

    Alves, M. I. R.; Jelić, V.; Ferrière, K.; Boulanger, F.

    2016-12-01

    Magnetic fields are a key constituent of the interstellar medium of our Galaxy. However, their exact role in the Galactic ecosystem is still poorly understood since we do not yet have a complete view of its structure in the Galaxy. This is about to change with the Faraday tomography technique, which allows us to derive the magnetic field in separate regions along the line of sight. We first describe the principle of Faraday tomography and illustrate the power of this novel technique with some of the latest results from the LOw Frequency ARray (LOFAR). We present preliminary results of our LOFAR project, aimed at investigating the origin of the filamentary-like structures revealed by Faraday tomography observations.

  17. Fabry-Perot enhanced Faraday rotation in graphene.

    PubMed

    Ubrig, Nicolas; Crassee, Iris; Levallois, Julien; Nedoliuk, Ievgeniia O; Fromm, Felix; Kaiser, Michl; Seyller, Thomas; Kuzmenko, Alexey B

    2013-10-21

    We demonstrate that giant Faraday rotation in graphene in the terahertz range due to the cyclotron resonance is further increased by constructive Fabry-Perot interference in the supporting substrate. Simultaneously, an enhanced total transmission is achieved, making this effect doubly advantageous for graphene-based magneto-optical applications. As an example, we present far-infrared spectra of epitaxial multilayer graphene grown on the C-face of 6H-SiC, where the interference fringes are spectrally resolved and a Faraday rotation up to 0.15 radians (9°) is attained. Further, we discuss and compare other ways to increase the Faraday rotation using the principle of an optical cavity.

  18. Evaluation of Plume Divergence and Facility Effects on Far-Field Faraday Probe Current Density Profiles

    DTIC Science & Technology

    2009-09-01

    elevated background pressure, compared nude Faraday probe designs, and evaluated design modifications to minimize uncertainty due to charge exchange...evaluated Faraday probe design and facility background pressure on collected ion current. A comparison of two nude Faraday probe designs concluded...140.5 Plasma potential in the region surrounding a nude Faraday probe has been measured to study the possibility of probe bias voltage acting as a

  19. Evaluation of ion collection area in Faraday probes.

    PubMed

    Brown, Daniel L; Gallimore, Alec D

    2010-06-01

    A Faraday probe with three concentric rings was designed and fabricated to assess the effect of gap width and collector diameter in a systematic study of the diagnostic ion collection area. The nested Faraday probe consisted of two concentric collector rings and an outer guard ring, which enabled simultaneous current density measurements on the inner and outer collectors. Two versions of the outer collector were fabricated to create gaps of 0.5 and 1.5 mm between the rings. Distribution of current density in the plume of a low-power Hall thruster ion source was measured in azimuthal sweeps at constant radius from 8 to 20 thruster diameters downstream of the exit plane with variation in facility background pressure. A new analytical technique is proposed to account for ions collected in the gap between the Faraday probe collector and guard ring. This method is shown to exhibit excellent agreement between all nested Faraday probe configurations, and to reduce the magnitude of integrated ion beam current to levels consistent with Hall thruster performance analyses. The technique is further studied by varying the guard ring bias potential with a fixed collector bias potential, thereby controlling ion collection in the gap. Results are in agreement with predictions based on the proposed analytical technique. The method is applied to a past study comparing the measured ion current density profiles of two Faraday probe designs. These findings provide new insight into the nature of ion collection in Faraday probe diagnostics, and lead to improved accuracy with a significant reduction in measurement uncertainty.

  20. All-Fiber Optical Faraday Mirror Using 56-wt%-Terbium-Doped Fiber

    SciTech Connect

    Sun, L.; Jiang, S.; Marciante, J.R.

    2010-06-22

    An all-fiber optical Faraday mirror that consists of a fiber Faraday rotator and a fiber Bragg grating is demonstrated. The fiber Faraday rotator uses a 21-cm-long section of 56-wt%-terbium-doped silicate fiber. The polarization state of the reflected light is rotated 89 degrees +/- 2 degrees with a 16-dB polarization extinction ratio.

  1. Compensation of thermally induced polarisation distortions in Faraday isolators

    SciTech Connect

    Khazanov, E A

    1999-01-31

    Two new Faraday isolator designs are proposed. They make it possible to compensate partly for the depolarisation of radiation which occurs in magneto-optical elements because of the photoelastic effect caused by heating associated with the absorption of laser radiation. Analytic and numerical comparisons of the new and traditional designs demonstrate a significant (by orders of magnitude) increase in the isolation ratio of the new isolators. The results obtained indicate that it should be possible to construct a Faraday isolator with the isolation ratio of 30 dB for laser radiation with an average power of several kilowatts. (laser applications and other topics in quantum electronics)

  2. Earth-based observations of Faraday rotation in radio bursts from Jupiter

    NASA Technical Reports Server (NTRS)

    Phillips, J. A.; Ferree, Thomas C.; Wang, Joe

    1989-01-01

    New observations have been made of Faraday rotation in decameter-wavelength radio bursts from the planet Jupiter. Data obtained during six Io-B storms clearly indicate that an appreciable fraction of the observed Faraday rotation occurs in the Jovian magnetosphere. All of the Faraday rotation observed during a single Io-A storm can be accounted for by earth's ionosphere. Measurements of the Faraday effect in Io-B emissions indicate that the source is in Jupiter's northern magnetic hemisphere. Observations of the Faraday effect in Io-C emissions are proposed to determine its location as well.

  3. Faraday's Investigation of Electromagnetic Induction. Experiment No. 21.

    ERIC Educational Resources Information Center

    Devons, Samuel

    This paper focuses on Michael Faraday's experimental research in electricity in the 1830's. Historical notes related to his work are included as well as experiments, his objectives, and illustrations of equipment for the experiments. Examples from his diary are given so that students can attempt to emulate his honest and systematic manner of…

  4. High-power Faraday isolators based on TAG ceramics.

    PubMed

    Zheleznov, Dmitry; Starobor, Aleksey; Palashov, Oleg; Chen, Chong; Zhou, Shengming

    2014-02-10

    The Faraday isolator based on a new magneto-optical medium--TAG (terbium aluminum garnet) ceramics was implemented and investigated experimentally. The magneto-optical element was temperature-stabilized using water cooling. The device provides a stable isolation ratio of 38 dB at 300 W laser power. Estimates show high performance of the device at a kilowatt laser power.

  5. Michael Faraday: Prince of lecturers in Victorian England

    NASA Astrophysics Data System (ADS)

    Lan, Boon Leong; Lim, Jeanette B. S.

    2001-01-01

    In this note, we focus on Faraday as a lecturer/teacher. We trace his development as a lecturer/teacher and highlight his approaches in popular-science lecturing and in teaching chemistry to military cadets. We appraise his success and conclude with an account of his poignant last lecture.

  6. Faraday, Dickens and Science Education in Victorian Britain

    ERIC Educational Resources Information Center

    Melville, Wayne; Allingham, Philip V.

    2011-01-01

    The achievements of Michael Faraday in the fields of electricity and electrochemistry have led some to describe him as the greatest experimental scientist in history. Charles Dickens was the creative genius behind some of the most memorable characters in literature. In this article, we share an historical account of how the collaboration of these…

  7. Professor Henry, Mr. Faraday, and the Hunt for Electromagnetic Induction

    NASA Astrophysics Data System (ADS)

    Moyer, Albert E.

    1997-04-01

    On different sides of the Atlantic but about the same time, Michael Faraday and Joseph Henry announced success in a quest that had preoccupied the scientific community for a decade: coaxing electricity from magnetism. "Mutual induction," what Faraday and Henry had identified in the early 1830s, would turn out to be not only a foundational concept in the physics of electricity and magnetism but also the principle behind the technology of electrical transformers and generators--two mainstays of industrialization. Although Faraday's breakthrough in London and Henry's in Albany might appear to be classic examples of "independent discovery," they were not. The two natural philosophers shared a similar orientation toward their research and, moreover, a distinctive laboratory instrument: Henry's new, powerful electromagnet. Thus, the story of Henry's and Faraday's search for induction illuminates not only the workings of Victorian science but also the crucial part that an instrument--the unadorned hardware--can play in scientific inquiry. Albert Moyer takes this story from his biography of Joseph Henry that Smithsonian Institution Press is about to publish in commemoration of the 200th anniversary of Henry's birth. The biography focuses on Henry's early and middle years, 1797-1847, from his emergence as America's foremost physical scientist to his election as the Smithsonian Institution's first director.

  8. Faraday signature of magnetic helicity from reduced depolarization

    SciTech Connect

    Brandenburg, Axel; Stepanov, Rodion

    2014-05-10

    Using one-dimensional models, we show that a helical magnetic field with an appropriate sign of helicity can compensate the Faraday depolarization resulting from the superposition of Faraday-rotated polarization planes from a spatially extended source. For radio emission from a helical magnetic field, the polarization as a function of the square of the wavelength becomes asymmetric with respect to zero. Mathematically speaking, the resulting emission occurs then either at observable or at unobservable (imaginary) wavelengths. We demonstrate that rotation measure (RM) synthesis allows for the reconstruction of the underlying Faraday dispersion function in the former case, but not in the latter. The presence of positive magnetic helicity can thus be detected by observing positive RM in highly polarized regions in the sky and negative RM in weakly polarized regions. Conversely, negative magnetic helicity can be detected by observing negative RM in highly polarized regions and positive RM in weakly polarized regions. The simultaneous presence of two magnetic constituents with opposite signs of helicity is shown to possess signatures that can be quantified through polarization peaks at specific wavelengths and the gradient of the phase of the Faraday dispersion function. Similar polarization peaks can tentatively also be identified for the bi-helical magnetic fields that are generated self-consistently by a dynamo from helically forced turbulence, even though the magnetic energy spectrum is then continuous. Finally, we discuss the possibility of detecting magnetic fields with helical and non-helical properties in external galaxies using the Square Kilometre Array.

  9. Theoretical model for a Faraday anomalous dispersion optical filter

    NASA Technical Reports Server (NTRS)

    Yin, B.; Shay, T. M.

    1991-01-01

    A model for the Faraday anomalous dispersion optical filter is presented. The model predicts a bandwidth of 0.6 GHz and a transmission peak of 0.98 for a filter operating on the Cs (D2) line. The model includes hyperfine effects and is valid for arbitrary magnetic fields.

  10. Concluding remarks: Faraday Discussion on chemistry in the urban atmosphere.

    PubMed

    Jimenez, Jose L

    2016-07-18

    This article summarises the Concluding remarks from the Faraday Discussion on Chemistry in the Urban Atmosphere. The following themes are addressed: (a) new results that inform our understanding of the evolving sources and composition of the urban atmosphere ("News"); (b) results that identify gaps in our understanding that necessitate further work ("Gaps");

  11. VLA Measurements of Faraday Rotation through Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Kooi, Jason E.; Fischer, Patrick D.; Buffo, Jacob J.; Spangler, Steven R.

    2017-04-01

    Coronal mass ejections (CMEs) are large-scale eruptions of plasma from the Sun, which play an important role in space weather. Faraday rotation is the rotation of the plane of polarization that results when a linearly polarized signal passes through a magnetized plasma such as a CME. Faraday rotation is proportional to the path integral through the plasma of the electron density and the line-of-sight component of the magnetic field. Faraday-rotation observations of a source near the Sun can provide information on the plasma structure of a CME shortly after launch. We report on simultaneous white-light and radio observations made of three CMEs in August 2012. We made sensitive Very Large Array (VLA) full-polarization observations using 1 - 2 GHz frequencies of a constellation of radio sources through the solar corona at heliocentric distances that ranged from 6 - 15 R_{⊙}. Two sources (0842+1835 and 0900+1832) were occulted by a single CME, and one source (0843+1547) was occulted by two CMEs. In addition to our radioastronomical observations, which represent one of the first active hunts for CME Faraday rotation since Bird et al. ( Solar Phys., 98, 341, 1985) and the first active hunt using the VLA, we obtained white-light coronagraph images from the Large Angle and Spectrometric Coronagraph (LASCO) C3 instrument to determine the Thomson-scattering brightness [BT], providing a means to independently estimate the plasma density and determine its contribution to the observed Faraday rotation. A constant-density force-free flux rope embedded in the background corona was used to model the effects of the CMEs on BT and Faraday rotation. The plasma densities (6 - 22×103 cm^{-3}) and axial magnetic-field strengths (2 - 12 mG) inferred from our models are consistent with the modeling work of Liu et al. ( Astrophys. J., 665, 1439, 2007) and Jensen and Russell ( Geophys. Res. Lett., 35, L02103, 2008), as well as previous CME Faraday-rotation observations by Bird et al

  12. Faraday Probe Analysis, Part 2: Evaluation of Facility Effects on Ion Migration in a Hall Thruster Plume (Preprint)

    DTIC Science & Technology

    2010-02-24

    and may alter the thruster performance and plume properties [1,2,3]. A number of investigations have studied nude Faraday probe design...Release, Distribution Unlimited (JA-2010-064) 3 propulsion plumes. One approach is to attach a collimator to the entrance of a nude Faraday probe to...energy CEX ions. A study by Rovey [5] compared results from a magnetically filtered Faraday probe, a boxed Faraday probe, and a nude Faraday probe to

  13. CRADA Final Report, 2011S003, Faraday Technologies

    SciTech Connect

    Faraday Technologies

    2012-12-12

    This Phase I SBIR program addressed the need for an improved manufacturing process for electropolishing niobium RF superconducting cavities for the International Linear Collider (ILC). The ILC is a proposed particle accelerator that will be used to gain a deeper understanding of the forces of energy and matter by colliding beams of electrons and positrons at nearly the speed of light. The energy required for this to happen will be achieved through the use of advanced superconducting technology, specifically ~16,000 RF superconducting cavities operating at near absolute zero. The RF superconductor cavities will be fabricated from highly pure Nb, which has an extremely low surface resistance at 2 Kelvin when compared to other materials. To take full advantage of the superconducting properties of the Nb cavities, the inner surface must be a) polished to a microscale roughness < 0.1 µm with removal of at least 100 µm of material, and b) cleaned to be free of impurities that would degrade performance of the ILC. State-of-the-art polishing uses either chemical polishing or electropolishing, both of which require hydrofluoric acid to achieve breakdown of the strong passive film on the surface. In this Phase I program, Faraday worked with its collaborators at the Thomas Jefferson National Accelerator Facility (JLab) to demonstrate the feasibility of an electropolishing process for pure niobium, utilizing an environmentally benign alternative to chemical or electrochemical polishing electrolytes containing hydrofluoric acid. Faraday utilized a 31 wt% aqueous sulfuric acid solution (devoid of hydrofluoric acid) in conjunction with the FARADAYICSM Process, which uses pulse/pulse reverse fields for electropolishing, to demonstrate the ability to electropolish niobium to the desired surface finish. The anticipated benefits of the FARADAYICSM Electropolishing process will be a simpler, safer, and less expensive method capable of surface finishing high purity niobium cavities

  14. Todd, Faraday and the electrical basis of brain activity.

    PubMed

    Reynolds, Edward

    2007-10-01

    The origins of our understanding of brain electricity and electrical discharges in epilepsy can be traced to Robert Bentley Todd (1809-60). Todd was influenced by his contemporary in London, Michael Faraday (1791-1867), who in the 1830 s and 1840 s was laying the foundations of our modern understanding of electromagnetism. Todd's concept of nervous polarity, generated in nerve vesicles and transmitted in nerve fibres (neurons in later terminology), was confirmed a century later by the Nobel Prize-winning work of Hodgkin and Huxley, who demonstrated the ionic basis of neuro-transmission, involving the same ions which had had been discovered by Faraday's mentor, Sir Humphry Davy (1778-1829).

  15. A Faraday effect position sensor for interventional magnetic resonance imaging.

    PubMed

    Bock, M; Umathum, R; Sikora, J; Brenner, S; Aguor, E N; Semmler, W

    2006-02-21

    An optical sensor is presented which determines the position and one degree of orientation within a magnetic resonance tomograph. The sensor utilizes the Faraday effect to measure the local magnetic field, which is modulated by switching additional linear magnetic fields, the gradients. Existing methods for instrument localization during an interventional MR procedure often use electrically conducting structures at the instruments that can heat up excessively during MRI and are thus a significant danger for the patient. The proposed optical Faraday effect position sensor consists of non-magnetic and electrically non-conducting components only so that heating is avoided and the sensor could be applied safely even within the human body. With a non-magnetic prototype set-up, experiments were performed to demonstrate the possibility of measuring both the localization and the orientation in a magnetic resonance tomograph. In a 30 mT m(-1) gradient field, a localization uncertainty of 1.5 cm could be achieved.

  16. Improved method for Faraday current sensor data processing

    NASA Astrophysics Data System (ADS)

    Ferrari, José A.; Perciante, César D.; Lagos, Alejandro; Frins, Erna M.

    2001-11-01

    There are several practical problems that have made difficult the prompt application of Faraday current sensors in industrial environments. Two of them are the multiplicative noise generated by mechanical vibrations and the normalization of the output signal. In this paper we propose a logarithmical processing and a posterior bandpass filtering of the sensor data in order to solve simultaneously both issues. Experimental results demonstrating the viability of the procedure and a comparison with standard processing methods are presented.

  17. Triangular-shaped bulk optic glass Faraday current sensor

    NASA Astrophysics Data System (ADS)

    Chu, Beatrice C.; Ning, Yanong N.; Jackson, David A.

    1993-03-01

    A new triangular topology for a bulk optic Faraday current sensor is presented with a demonstrated resolution of 20 mA/(root)Hz over a measurement range from 1 to 3000 A. The sensitivity of the system was 2.35 X 10-5 rad/A. This sensor is relatively easy to fabricate and overcome problems encountered using current sensors based upon bulk optic 'square' configurations and all fiber systems.

  18. Oscillon dynamics and rogue wave generation in Faraday surface ripples.

    PubMed

    Xia, H; Maimbourg, T; Punzmann, H; Shats, M

    2012-09-14

    We report new experimental results which suggest that the generation of extreme wave events in the Faraday surface ripples is related to the increase in the horizontal mobility of oscillating solitons (oscillons). The analysis of the oscillon trajectories in a horizontal plane shows that at higher vertical acceleration, oscillons move chaotically, merge and form enclosed areas on the water surface. The probability of the formation of such craters, which precede large wave events, increases with the increase in horizontal mobility.

  19. A new approach for miniaturization of multiple faraday cup collectors.

    SciTech Connect

    Banar, J. C.; Chamberlin, E. P.; Poths, J.; Perrin, R. E.; Chastagner, P.

    2002-01-01

    The mass spectrometry section in CST-7 has been working for several years on a novel so0lution to overcome the size and placement restrictions of multiple Faraday cup collectors. Use of simultaneous collection of multiple isotopes both increases precision in the isotopic measurements and shortens the data collection time. Our application is for the measurement of the isotopic composition of Xe, ionized in a source that produces a large (10{sup -11} amp) but variable ion beam.

  20. Midplane Faraday rotation: A densitometer for large tokamaks

    NASA Astrophysics Data System (ADS)

    Jobes, F. C.; Mansfield, D. K.

    1992-10-01

    The density in a large tokamak such as International Thermonuclear Experimental Reactor (ITER), or any of the proposed future US machines, can be determined by measuring the Faraday rotation of a 10.6 μm laser directed tangent to the toroidal field. If there is a horizontal array of such beams, then ne(R) can be readily obtained with a simple Abel inversion about the center line of the tokamak. For a large machine, operated at a full field of 30 T m and a density of 2×1020/m3, the rotation angle would be quite large-about 60° for two passes. A layout in which a single laser beam is fanned out in the horizontal midplane of the tokamak, with a set of retroreflectors on the far side of the vacuum vessel, would provide good spatial resolution, depending only upon the number of reflectors. With this proposed layout, only one window would be needed. Because the rotation angle is never more than 1 ``fringe,'' the data is always good, and it is also a continuous measurement in time. Faraday rotation is dependent only upon the plasma itself, and thus is not sensitive to vibration of the optical components. Simulations of the expected results show that ITER, or any large tokamak, existing or proposed, would be well served even at low densities by a midplane Faraday rotation densitometer of ˜64 channels.

  1. Todd, Faraday, and the electrical basis of brain activity.

    PubMed

    Reynolds, Edward H

    2004-09-01

    Robert Bentley Todd (1809-60) was the UK's first eminent neurologist and neuroscientist. An anatomist, physiologist, and clinical scientist with an interest in the nervous system, he was the first to confirm the electrical basis of brain activity in the 1840s. He was influenced by his contemporary, Michael Faraday at the Royal Institution, and by two colleagues at King's College, John Daniell and Charles Wheatstone, who were also working at the cutting edge of electrical science. Todd conceived of nervous polarity (force) generated in nervous centres and compared this with the polar force of voltaic electricity developed in the galvanic battery. He brilliantly foresaw each nerve vesicle (cell) and its related fibres (ie, neuron) as a distinct apparatus for the development and transmission of nervous polarity. Epilepsy was the result of periodic unnatural development of nervous force leading to the "disruptive discharge" described by Faraday. Faraday, who studied animal electricity in the Gymnotus (electric eel), and Todd saw nervous polarity as a higher form of interchangeable energy.

  2. Toward instructional design principles: Inducing Faraday's law with contrasting cases

    NASA Astrophysics Data System (ADS)

    Kuo, Eric; Wieman, Carl E.

    2016-06-01

    Although physics education research (PER) has improved instructional practices, there are not agreed upon principles for designing effective instructional materials. Here, we illustrate how close comparison of instructional materials could support the development of such principles. Specifically, in discussion sections of a large, introductory physics course, a pair of studies compare two instructional strategies for teaching a physics concept: having students (i) explain a set of contrasting cases or (ii) apply and build on previously learned concepts. We compare these strategies for the teaching of Faraday's law, showing that explaining a set of related contrasting cases not only improves student performance on Faraday's law questions over building on a previously learned concept (i.e., Lorentz force), but also prepares students to better learn subsequent topics, such as Lenz's law. These differences persist to the final exam. We argue that early exposure to contrasting cases better focuses student attention on a key feature related to both concepts: change in magnetic flux. Importantly, the benefits of contrasting cases for both learning and enjoyment are enhanced for students who did not first attend a Faraday's law lecture, consistent with previous research suggesting that being told a solution can circumvent the benefits of its discovery. These studies illustrate an experimental approach for understanding how the structure of activities affects learning and performance outcomes, a first step toward design principles for effective instructional materials.

  3. Effects of Faraday Rotation Observed in Filter Magnetograph Data

    NASA Technical Reports Server (NTRS)

    Hagyard, Mona J.; Adams, Mitzi L.; Smith, J. E.; West, Edward A.

    1999-01-01

    In this paper we analyze the effects of Faraday rotation on the azimuth of the transverse magnetic field from observations taken with the Marshall Space Flight Center's vector magnetograph for a simple sunspot observed on June 9, 1985. Vector magnetograms were obtained over the wavelength interval of 170 mA redward of line center of the Fe I 5250.22 A spectral line to 170 mA to the blue, in steps of 10 mA. These data were analyzed to produce the variation of the azimuth as a function of wavelength at each pixel over the field of vi ew of the sunspot. At selected locations in the sunspot, curves of the observed variation of azimuth with wavelength were compared with model calculations for the amount of Faraday rotation of the azimuth. From these comparisons we derived the amount of rotation as functions of bo th the magnitude and inclination of the sunspot's field and deduced the ranges of these field values for which Faraday rotation presents a significant problem in observations taken near the center of a spectral line.

  4. Analyzing Extragalactic Magnetic Fields Using Faraday Rotation Measure Synthesis

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  5. Effects of interband transitions on Faraday rotation in metallic nanoparticles.

    PubMed

    Wysin, G M; Chikan, Viktor; Young, Nathan; Dani, Raj Kumar

    2013-08-14

    The Faraday rotation in metallic nanoparticles is considered based on a quantum model for the dielectric function ϵ(ω) in the presence of a DC magnetic field B. We focus on effects in ϵ(ω) due to interband transitions (IBTs), which are important in the blue and ultraviolet for noble metals used in plasmonics. The dielectric function is found using the perturbation of the electron density matrix due to the optical field of the incident electromagnetic radiation. The calculation is applied to transitions between two bands (d and p, for example) separated by a gap, as one finds in gold at the L-point of the Fermi surface. The result of the DC magnetic field is a shift in the effective optical frequency causing IBTs by ±μBB/ħ, where opposite signs are associated with left/right circular polarizations. The Faraday rotation for a dilute solution of 17 nm diameter gold nanoparticles is measured and compared with both the IBT theory and a simpler Drude model for the bound electron response. Effects of the plasmon resonance mode on Faraday rotation in nanoparticles are also discussed.

  6. Development and first experimental tests of Faraday cup array.

    PubMed

    Prokůpek, J; Kaufman, J; Margarone, D; Krůs, M; Velyhan, A; Krása, J; Burris-Mog, T; Busold, S; Deppert, O; Cowan, T E; Korn, G

    2014-01-01

    A new type of Faraday cup, capable of detecting high energy charged particles produced in a high intensity laser-matter interaction environment, has recently been developed and demonstrated as a real-time detector based on the time-of-flight technique. An array of these Faraday cups was designed and constructed to cover different observation angles with respect to the target normal direction. Thus, it allows reconstruction of the spatial distribution of ion current density in the subcritical plasma region and the ability to visualise its time evolution through time-of-flight measurements, which cannot be achieved with standard laser optical interferometry. This is a unique method for two-dimensional visualisation of ion currents from laser-generated plasmas. A technical description of the new type of Faraday cup is introduced along with an ad hoc data analysis procedure. Experimental results obtained during campaigns at the Petawatt High-Energy Laser for Heavy Ion Experiments (GSI, Darmstadt) and at the Prague Asterix Laser System (AS CR) are presented. Advantages and limitations of the used diagnostic system are discussed.

  7. Faraday rotation data analysis with least-squares elliptical fitting

    SciTech Connect

    White, Adam D.; McHale, G. Brent; Goerz, David A.; Speer, Ron D.

    2010-10-15

    A method of analyzing Faraday rotation data from pulsed magnetic field measurements is described. The method uses direct least-squares elliptical fitting to measured data. The least-squares fit conic parameters are used to rotate, translate, and rescale the measured data. Interpretation of the transformed data provides improved accuracy and time-resolution characteristics compared with many existing methods of analyzing Faraday rotation data. The method is especially useful when linear birefringence is present at the input or output of the sensing medium, or when the relative angle of the polarizers used in analysis is not aligned with precision; under these circumstances the method is shown to return the analytically correct input signal. The method may be pertinent to other applications where analysis of Lissajous figures is required, such as the velocity interferometer system for any reflector (VISAR) diagnostics. The entire algorithm is fully automated and requires no user interaction. An example of algorithm execution is shown, using data from a fiber-based Faraday rotation sensor on a capacitive discharge experiment.

  8. Faraday rotation dispersion microscopy imaging of diamagnetic and chiral liquids with pulsed magnetic field.

    PubMed

    Suwa, Masayori; Nakano, Yusuke; Tsukahara, Satoshi; Watarai, Hitoshi

    2013-05-21

    We have constructed an experimental setup for Faraday rotation dispersion imaging and demonstrated the performance of a novel imaging principle. By using a pulsed magnetic field and a polarized light synchronized to the magnetic field, quantitative Faraday rotation images of diamagnetic organic liquids in glass capillaries were observed. Nonaromatic hydrocarbons, benzene derivatives, and naphthalene derivatives were clearly distinguished by the Faraday rotation images due to the difference in Verdet constants. From the wavelength dispersion of the Faraday rotation images in the visible region, it was found that the resonance wavelength in the UV region, which was estimated based on the Faraday B-term, could be used as characteristic parameters for the imaging of the liquids. Furthermore, simultaneous acquisition of Faraday rotation image and natural optical rotation image was demonstrated for chiral organic liquids.

  9. Observation of two-dimensional Faraday waves in extremely shallow depth.

    PubMed

    Li, Xiaochen; Yu, Zhengyue; Liao, Shijun

    2015-09-01

    A family of two-dimensional Faraday waves in extremely shallow depth (1 mm to 2 mm) of absolute ethanol are observed experimentally using a Hele-Shaw cell that vibrates vertically. The same phenomena are not observed by means of water, ethanol solution, and silicone oil. These Faraday waves are quite different from the traditional ones. These phenomena are helpful to deepen and enrich our understandings about Faraday waves, and besides provide a challenging problem for computational fluid dynamics.

  10. Quantum Faraday effect in a double-dot Aharonov-Bohm loop

    NASA Astrophysics Data System (ADS)

    Kang, Kicheon

    2012-07-01

    We investigate the role of Faraday's law of induction manifested in the quantum state of Aharonov-Bohm (AB) loops. In particular, a flux-switching experiment is proposed for a double-dot AB loop to verify the phase shift induced by Faraday's law. The induced Faraday phase is shown to be geometric and nontopological. This study demonstrates that the relation between the local phases of a ring at different fluxes is not arbitrary but is instead determined by Faraday's inductive law, which is in contrast to the arbitrary local phase of an AB loop for a given flux.

  11. Comparison of algorithms for determination of rotation measure and Faraday structure. I. 1100–1400 MHz

    SciTech Connect

    Sun, X. H.; Akahori, Takuya; Anderson, C. S.; Farnes, J. S.; O’Sullivan, S. P.; Rudnick, L.; O’Brien, T.; Bell, M. R.; Bray, J. D.; Scaife, A. M. M.; Ideguchi, S.; Kumazaki, K.; Stepanov, R.; Stil, J.; Wolleben, M.; Takahashi, K.; Weeren, R. J. van E-mail: larry@umn.edu

    2015-02-01

    Faraday rotation measures (RMs) and more general Faraday structures are key parameters for studying cosmic magnetism and are also sensitive probes of faint ionized thermal gas. A definition of which derived quantities are required for various scientific studies is needed, as well as addressing the challenges in determining Faraday structures. A wide variety of algorithms has been proposed to reconstruct these structures. In preparation for the Polarization Sky Survey of the Universe's Magnetism (POSSUM) to be conducted with the Australian Square Kilometre Array Pathfinder and the ongoing Galactic Arecibo L-band Feeds Array Continuum Transit Survey (GALFACTS), we run a Faraday structure determination data challenge to benchmark the currently available algorithms, including Faraday synthesis (previously called RM synthesis in the literature), wavelet, compressive sampling, and QU-fitting. The input models include sources with one Faraday thin component, two Faraday thin components, and one Faraday thick component. The frequency set is similar to POSSUM/GALFACTS with a 300 MHz bandwidth from 1.1 to 1.4 GHz. We define three figures of merit motivated by the underlying science: (1) an average RM weighted by polarized intensity, RM{sub wtd}, (2) the separation Δϕ of two Faraday components, and (3) the reduced chi-squared χ{sub r}{sup 2}. Based on the current test data with a signal-to-noise ratio of about 32, we find the following. (1) When only one Faraday thin component is present, most methods perform as expected, with occasional failures where two components are incorrectly found. (2) For two Faraday thin components, QU-fitting routines perform the best, with errors close to the theoretical ones for RM{sub wtd} but with significantly higher errors for Δϕ. All other methods, including standard Faraday synthesis, frequently identify only one component when Δϕ is below or near the width of the Faraday point-spread function. (3) No methods as currently implemented

  12. Ultrafast magnetic vortex core switching driven by the topological inverse Faraday effect.

    PubMed

    Taguchi, Katsuhisa; Ohe, Jun-ichiro; Tatara, Gen

    2012-09-21

    We present a theoretical discovery of an unconventional mechanism of inverse Faraday effect which acts selectively on topological magnetic structures. The effect, topological inverse Faraday effect, is induced by the spin Berry's phase of the magnetic structure when a circularly polarized light is applied. Thus a spin-orbit interaction is not necessary unlike that in the conventional inverse Faraday effect. We demonstrate by numerical simulation that topological inverse Faraday effect realizes ultrafast switching of a magnetic vortex within a switching time of 150 ps without magnetic field.

  13. A novel Cs-(129)Xe atomic spin gyroscope with closed-loop Faraday modulation.

    PubMed

    Fang, Jiancheng; Wan, Shuangai; Qin, Jie; Zhang, Chen; Quan, Wei; Yuan, Heng; Dong, Haifeng

    2013-08-01

    We report a novel Cs-(129)Xe atomic spin gyroscope (ASG) with closed-loop Faraday modulation method. This ASG requires approximately 30 min to start-up and 110 °C to operate. A closed-loop Faraday modulation method for measurement of the optical rotation was used in this ASG. This method uses an additional Faraday modulator to suppress the laser intensity fluctuation and Faraday modulator thermal induced fluctuation. We theoretically and experimentally validate this method in the Cs-(129)Xe ASG and achieved a bias stability of approximately 3.25 °∕h.

  14. Comparison of Algorithms for Determination of Rotation Measure and Faraday Structure. I. 1100-1400 MHz

    NASA Astrophysics Data System (ADS)

    Sun, X. H.; Rudnick, L.; Akahori, Takuya; Anderson, C. S.; Bell, M. R.; Bray, J. D.; Farnes, J. S.; Ideguchi, S.; Kumazaki, K.; O'Brien, T.; O'Sullivan, S. P.; Scaife, A. M. M.; Stepanov, R.; Stil, J.; Takahashi, K.; van Weeren, R. J.; Wolleben, M.

    2015-02-01

    Faraday rotation measures (RMs) and more general Faraday structures are key parameters for studying cosmic magnetism and are also sensitive probes of faint ionized thermal gas. A definition of which derived quantities are required for various scientific studies is needed, as well as addressing the challenges in determining Faraday structures. A wide variety of algorithms has been proposed to reconstruct these structures. In preparation for the Polarization Sky Survey of the Universe's Magnetism (POSSUM) to be conducted with the Australian Square Kilometre Array Pathfinder and the ongoing Galactic Arecibo L-band Feeds Array Continuum Transit Survey (GALFACTS), we run a Faraday structure determination data challenge to benchmark the currently available algorithms, including Faraday synthesis (previously called RM synthesis in the literature), wavelet, compressive sampling, and QU-fitting. The input models include sources with one Faraday thin component, two Faraday thin components, and one Faraday thick component. The frequency set is similar to POSSUM/GALFACTS with a 300 MHz bandwidth from 1.1 to 1.4 GHz. We define three figures of merit motivated by the underlying science: (1) an average RM weighted by polarized intensity, R{{M}wtd}, (2) the separation Δφ of two Faraday components, and (3) the reduced chi-squared χ r2. Based on the current test data with a signal-to-noise ratio of about 32, we find the following. (1) When only one Faraday thin component is present, most methods perform as expected, with occasional failures where two components are incorrectly found. (2) For two Faraday thin components, QU-fitting routines perform the best, with errors close to the theoretical ones for R{{M}wtd} but with significantly higher errors for Δφ . All other methods, including standard Faraday synthesis, frequently identify only one component when Δφ is below or near the width of the Faraday point-spread function. (3) No methods as currently implemented work well for

  15. Michael Faraday, 30,000 Teenagers and Climate Change

    NASA Astrophysics Data System (ADS)

    Giles, K. A.; Wingham, D. J.

    2006-12-01

    One of the objectives of IPY is to engage the awareness, interest and understanding of schoolchildren, the general public and decision-makers worldwide in the purpose and value of polar research and monitoring. Between January and March 2006 I co-presented the Faraday Lecture, run by the Institution of Engineering Technology, which aims to interest the public, and young people in particular, in science and engineering. The topic of the lecture this year was climate change and the technologies that have the potential to reduce our carbon dioxide emissions. As a research fellow at the Centre for Polar Observation and Modelling, University College London, I was able to use my knowledge of the polar regions to help explain the fundamentals of human induced climate change, from using ice cores for paleoclimate studies to what would happen if Greenland melted. The lecture was attended by 30,000 people, mainly aged between 14 to 16, at theatres across the UK and Asia, as well as broadcast on the web to North America and Europe. While the lecture was generally well received, it was apparent that there are misconceptions about the roles of scientists and engineers and a limited understanding of the polar regions and why they are important. The Faraday Lecture is a useful example of a large-scale vehicle for public understanding of science, and for assessing what works and what does not work when addressing young audiences. We consider the lessons learnt from the Faraday lectures in terms of bringing the IPY activities to the attention of the next generation of polar scientists using not only lectures, but a also wider variety of multi-media techniques.

  16. Kalman filter-based fast track reconstruction for charged particles in a Compressed Baryonic Matter experiment using parallel computing on a multicore server at the Laboratory of Information Technologies, Joint Institute for Nuclear Research

    NASA Astrophysics Data System (ADS)

    Ablyazimov, T. O.; Zyzak, M. V.; Ivanov, V. V.; Kisel, P. I.

    2015-05-01

    One of the main goals in the Compressed Baryonic Matter (CBM) experiment (GSI, Germany) is to find parameters of charged particle trajectories. An online full event reconstruction is planned to be carried out in this experiment, thus demanding fast algorithms be developed, which make the most of the capabilities of modern CPU and GPU architectures. This paper presents the results of an analysis of the Kalman filter-based track reconstruction for charged particles implemented by using various code parallelization methods. A multicore server located at the Laboratory of Information Technologies, Joint Institute for Nuclear Research (LIT JINR), with two CPU Intel Xeon X5660 processors and a GPU Nvidia GTX 480 video card is used.

  17. RF-sheath assessment of ICRF Faraday Screens

    SciTech Connect

    Colas, L.

    2007-09-28

    The line-integrated parallel RF electric field {delta}V{sub RF} is studied on 'long field lines' radially in front of an ICRF antenna closed by a Faraday screen (FS). Several issues are addressed analytically and numerically. To what extent is a FS necessary to shield {delta}V{sub RF} in presence of magnetized plasma, depending on strap phasing? How efficient is it as a function of FS misalignment on tilted magnetic field? Can a FS attenuate {delta}V{sub RF} produced on antenna frame?.

  18. Faraday rotator based on TSAG crystal with <001> orientation.

    PubMed

    Yasuhara, Ryo; Snetkov, Ilya; Starobor, Aleksey; Mironov, Evgeniy; Palashov, Oleg

    2016-07-11

    A Faraday isolator (FI) for high-power lasers with kilowatt-level average power and 1-µm wavelength was demonstrated using a terbium scandium aluminum garnet (TSAG) with its crystal axis aligned in the <001> direction. Furthermore, no compensation scheme for thermally induced depolarization in a magnetic field was used. An isolation ratio of 35.4 dB (depolarization ratio γ of 2.9 × 10-4) was experimentally observed at a maximum laser power of 1470 W. This result for room-temperature FIs is the best reported, and provides a simple, practical solution for achieving optical isolation in high-power laser systems.

  19. Faraday cup: absolute dosimetry for ELIMED beam line

    NASA Astrophysics Data System (ADS)

    Leanza, R.; Romano, F.; Scuderi, V.; Amico, A. G.; Cuttone, G.; Larosa, G.; Margarone, D.; Milluzzo, G.; Petringa, G.; Pipek, J.; Schillaci, F.; Cirrone, G. A. P.

    2017-03-01

    The scientific community has shown a growing interest towards multidisciplinary applications of laser-driven beams. In this framework, the ELIMED (ELI-Beamlines MEDical and multidisciplinary applications) beamline will be the first transport beamline dedicated to the medical and multidisciplinary studies with laser-accelerated ion beams. Detectors for dosimetry represent one of key-element of the ELIMED beamline, allowing a dose delivering with good result as required in the clinical applications. In this contribution, a Faraday Cup for absolute dosimetry, designed and realized at INFN-LNS, is described.

  20. A model for Faraday pilot waves over variable topography

    NASA Astrophysics Data System (ADS)

    Faria, Luiz M.

    2017-01-01

    Couder and Fort discovered that droplets walking on a vibrating bath possess certain features previously thought to be exclusive to quantum systems. These millimetric droplets synchronize with their Faraday wavefield, creating a macroscopic pilot-wave system. In this paper we exploit the fact that the waves generated are nearly monochromatic and propose a hydrodynamic model capable of quantitatively capturing the interaction between bouncing drops and a variable topography. We show that our reduced model is able to reproduce some important experiments involving the drop-topography interaction, such as non-specular reflection and single-slit diffraction.

  1. Response function of modulated grid Faraday cup plasma instruments

    NASA Technical Reports Server (NTRS)

    Barnett, A.; Olbert, S.

    1986-01-01

    Modulated grid Faraday cup plasma analyzers are a very useful tool for making in situ measurements of space plasmas. One of their great attributes is that their simplicity permits their angular response function to be calculated theoretically. An expression is derived for this response function by computing the trajectories of the charged particles inside the cup. The Voyager plasma science experiment is used as a specific example. Two approximations to the rigorous response function useful for data analysis are discussed. Multisensor analysis of solar wind data indicates that the formulas represent the true cup response function for all angles of incidence with a maximum error of only a few percent.

  2. Faraday rotation in bilayer graphene-based integrated microcavity.

    PubMed

    Da, Hai-Xia; Yan, Xiao-Hong

    2016-01-01

    Bernal-stacked bilayer graphene has rich ground states with various broken symmetries, allowing the existence of magneto-optical (MO) effects even in the absence of an external magnetic field. Here we report controllable Faraday rotation (FR) of bilayer graphene induced by electrostatic gate voltage, whose value is 10 times smaller than the case of single layer graphene with a magnetic field. A proposed bilayer graphene-based microcavity configuration enables the enhanced FR angle due to the large localized electromagnetic field. Our results offer unique opportunities to apply bilayer graphene for MO devices.

  3. Representing the Electromagnetic Field: How Maxwell's Mathematics Empowered Faraday's Field Theory

    ERIC Educational Resources Information Center

    Tweney, Ryan D.

    2011-01-01

    James Clerk Maxwell "translated" Michael Faraday's experimentally-based field theory into the mathematical representation now known as "Maxwell's Equations." Working with a variety of mathematical representations and physical models Maxwell extended the reach of Faraday's theory and brought it into consistency with other…

  4. Polarization-induced phase noise in fiber optic Michelson interferometer with Faraday rotator mirrors

    NASA Astrophysics Data System (ADS)

    Wu, Yuefeng; Li, Fang; Zhang, Wentao; Xiao, Hao; Liu, Yuliang

    2008-11-01

    Polarization-induced phase noise in Michelson interferometer with imperfect Faraday rotator mirrors was investigated. This kind of noise generates from the rotation angle errors of Faraday rotator mirrors and external polarization perturbation. The conversion factor κ, representing the magnitude conversion ability from polarization-noise to polarization induced phase-noise, have been theoretically evaluated and experimentally investigated.

  5. Nonreciprocal plasmonics enables giant enhancement of thin-film Faraday rotation.

    PubMed

    Chin, Jessie Yao; Steinle, Tobias; Wehlus, Thomas; Dregely, Daniel; Weiss, Thomas; Belotelov, Vladimir I; Stritzker, Bernd; Giessen, Harald

    2013-01-01

    Light propagation is usually reciprocal. However, a static magnetic field along the propagation direction can break the time-reversal symmetry in the presence of magneto-optical materials. The Faraday effect in magneto-optical materials rotates the polarization plane of light, and when light travels backward the polarization is further rotated. This is applied in optical isolators, which are of crucial importance in optical systems. Faraday isolators are typically bulky due to the weak Faraday effect of available magneto-optical materials. The growing research endeavour in integrated optics demands thin-film Faraday rotators and enhancement of the Faraday effect. Here, we report significant enhancement of Faraday rotation by hybridizing plasmonics with magneto-optics. By fabricating plasmonic nanostructures on laser-deposited magneto-optical thin films, Faraday rotation is enhanced by one order of magnitude in our experiment, while high transparency is maintained. We elucidate the enhanced Faraday effect by the interplay between plasmons and different photonic waveguide modes in our system.

  6. A Left-Hand Rule for Faraday's Law

    ERIC Educational Resources Information Center

    Salu, Yehuda

    2014-01-01

    A left-hand rule for Faraday's law is presented here. This rule provides a simple and quick way of finding directional relationships between variables of Faraday's law without using Lenz's rule.

  7. The continuity of scientific discovery and its communication: the example of Michael Faraday.

    PubMed

    Gross, Alan G

    2009-02-25

    This paper documents the cognitive strategies that led to Faraday's first significant scientific discovery. For Faraday, discovery is essentially a matter seeing as, of substituting for the eye all possess the eye of analysis all scientists must develop. In the process of making his first significant discovery, Faraday learns to dismiss the magnetic attractions and repulsions he and others had observed; by means of systematic variations in his experimental set-up, he learns to see these motions as circular: it is the first indication that an electro-magnetic field exists. In communicating his discoveries, Faraday, of course, takes into consideration his various audiences' varying needs and their differences in scientific competence; but whatever his audience, Faraday learns to convey what it feels like to do science, to shift from seeing to seeing as, from sight to insight.

  8. Faraday rotation enhancement of gold coated Fe2O3 nanoparticles: comparison of experiment and theory.

    PubMed

    Dani, Raj Kumar; Wang, Hongwang; Bossmann, Stefan H; Wysin, Gary; Chikan, Viktor

    2011-12-14

    Understanding plasmonic enhancement of nanoscale magnetic materials is important to evaluate their potential for application. In this study, the Faraday rotation (FR) enhancement of gold coated Fe(2)O(3) nanoparticles (NP) is investigated experimentally and theoretically. The experiment shows that the Faraday rotation of a Fe(2)O(3) NP solution changes from approximately 3 rad/Tm to 10 rad/Tm as 5 nm gold shell is coated on a 9.7 nm Fe(2)O(3) core at 632 nm. The results also show how the volume fraction normalized Faraday rotation varies with the gold shell thickness. From the comparison of experiment and calculated Faraday rotation based on the Maxwell-Garnett theory, it is concluded that the enhancement and shell dependence of Faraday rotation of Fe(2)O(3) NPs is a result of the shifting plasmon resonance of the composite NP. In addition, the clustering of the NPs induces a different phase lag on the Faraday signal, which suggests that the collective response of the magnetic NP aggregates needs to be considered even in solution. From the Faraday phase lag, the estimated time of the full alignment of the magnetic spins of bare (cluster size 160 nm) and gold coated NPs (cluster size 90 nm) are found to be 0.65 and 0.17 μs. The calculation includes a simple theoretical approach based on the Bruggeman theory to account for the aggregation and its effect on the Faraday rotation. The Bruggeman model provides a qualitatively better agreement with the experimentally observed Faraday rotation and points out the importance of making a connection between component properties and the average "effective" optical behavior of the Faraday medium containing magnetic nanoparticles.

  9. Resonant microsphere gyroscope based on a double Faraday rotator system.

    PubMed

    Xie, Chengfeng; Tang, Jun; Cui, Danfeng; Wu, Dajin; Zhang, Chengfei; Li, Chunming; Zhen, Yongqiu; Xue, Chenyang; Liu, Jun

    2016-10-15

    The resonant microsphere gyroscope is proposed based on a double Faraday rotator system for the resonant microsphere gyroscope (RMSG) that is characterized by low insertion losses and does not destroy the reciprocity of the gyroscope system. Use of the echo suppression structure and the orthogonal polarization method can effectively inhibit both the backscattering noise and the polarization error, and reduce them below the system sensitivity limit. The resonance asymmetry rate dropped from 34.2% to 2.9% after optimization of the backscattering noise and the polarization noise, which greatly improved the bias stability and the scale factor linearity of the proposed system. Additionally, based on the optimum parameters for the double Faraday rotator system, a bias stability of 0.04°/s has been established for an integration time of 10 s in 1000 s in a resonator microsphere gyroscope using a microsphere resonator with a diameter of 1 mm and a Q of 7.2×106.

  10. Protection characteristics of a Faraday cage compromised by lightning burnthrough.

    SciTech Connect

    Warne, Larry Kevin; Bystrom, Edward; Jorgenson, Roy Eberhardt; Montoya, Sandra L.; Merewether, Kimball O.; Coats, Rebecca Sue; Martinez, Leonard E.; Jojola, John M.

    2012-01-01

    A lightning flash consists of multiple, high-amplitude but short duration return strokes. Between the return strokes is a lower amplitude, continuing current which flows for longer duration. If the walls of a Faraday cage are made of thin enough metal, the continuing current can melt a hole through the metal in a process called burnthrough. A subsequent return stroke can couple energy through this newly-formed hole. This LDRD is a study of the protection provided by a Faraday cage when it has been compromised by burnthrough. We initially repeated some previous experiments and expanded on them in terms of scope and diagnostics to form a knowledge baseline of the coupling phenomena. We then used a combination of experiment, analysis and numerical modeling to study four coupling mechanisms: indirect electric field coupling, indirect magnetic field coupling, conduction through plasma and breakdown through the hole. We discovered voltages higher than those encountered in the previous set of experiments (on the order of several hundreds of volts).

  11. Cs 728 nm Laser Spectroscopy and Faraday Atomic Filter

    NASA Astrophysics Data System (ADS)

    Liu, Zhong-Zheng; Tao, Zhi-Ming; Jiang, Zhao-Jie; Chen, Jing-Biao

    2014-12-01

    We mainly present the 728 nm laser spectroscopy and Faraday atomic filter of Cs atoms with 650 MHz linewidth and 2.6% transmission based on an electrodeless discharge vapor lamp, compared with Rb 728 nm laser spectroscopy. Accidentally, this remarkably strong Cs 728 nm transition from the 6F7/2 state to the 5D5/2 state is only about 2.5 GHz away from the Rb 728 nm transition of the future potential four-level active optical clock, once laser cooled and trapped from the 7S1/2 state to the 5P1/2 state, as we proposed previously. A Faraday atomic filter stabilized 728 nm laser using a Cs electrodeless discharge vapor lamp with a power of 10mW will provide a frequency reference to evaluate the performance of the potential Rb four-level active optical clock at 728 nm with power less than 1 nW by 2.5 GHz heterodyne measurements.

  12. Elliptical polarization effects in a chromatically addressed Faraday current sensor

    NASA Astrophysics Data System (ADS)

    Li, G. D.; Aspey, R. A.; Kong, M. G.; Gibson, J. R.; Jones, G. R.

    1999-01-01

    Optical polarization processes in a parallel-sided glass element used in a Faraday rotation current sensor have been considered. In such sensors the path length necessary to produce sufficient rotation of the plane of polarization is produced by a multiplicity of reflections within the glass element. It is shown that such reflections induce ellipticity of polarization and that this affects the current-sensing performance of the sensor. Two reflection cases, corresponding to total internal reflections at a glass-air interface and reflections by aluminium-coated surfaces, are considered. The latter are shown to produce higher optical attenuation but a lower degree of elliptical polarization. The implications of the induced elliptical polarization in relation to chromatically modulated polychromatic light are considered. It is shown that the resolution of the Faraday sensing is improved by minimizing the ellipticity of the polarization with the aluminium-coated reflections. However a greater dynamic range and signal strength may be achievable with the total internal reflection element.

  13. A fast Adaptive-Gain Orientation Filter of inertial/magnetic data for human motion tracking in free-living environments.

    PubMed

    Tian, Ya; Tan, Jindong

    2012-01-01

    High-resolution, real-time data obtained by human motion tracking systems can be used for gait analysis, which helps better understanding the cause of many diseases for more effective treatments, such as rehabilitation for outpatients or recovery from lost motor functions after a stroke. This paper presents an analytically derived method for an adaptive-gain complementary filter based on the convergence rate from the Gauss-Newton optimization algorithm (GNA) and the divergence rate from the gyroscope, which is referred as Adaptive-Gain Orientation Filter (AGOF) in this paper. The AGOF has the advantages of one iteration calculation to reduce the computing load and accurate estimation of gyroscope measurement error. Moreover, for handling magnetic distortions especially in indoor environments and movements with excessive acceleration, adaptive measurement vectors and a reference vector for Earth's magnetic field selection schemes are introduced to help the GNA find more accurate direction of gyroscope error. Experimental results are presented to verify the performance of the proposed method, which shows better accuracy of orientation estimation than several well-known methods.

  14. Design of Faraday cup ion detectors built by thin film deposition

    NASA Astrophysics Data System (ADS)

    Szalkowski, G. A.; Darrow, D. S.; Cecil, F. E.

    2017-03-01

    Thin film Faraday cup detectors can provide measurements of fast ion loss from magnetically confined fusion plasmas. These multilayer detectors can resolve the energy distribution of the lost ions in addition to giving the total loss rate. Prior detectors were assembled from discrete foils and insulating sheets. Outlined here is a design methodology for creating detectors using thin film deposition that are suited to particular scientific goals. The intention is to use detectors created by this method on the Joint European Torus (JET) and the National Spherical Torus Experiment-Upgrade (NSTX-U). The detectors will consist of alternating layers of aluminum and silicon dioxide, with layer thicknesses chosen to isolate energies of interest. Thin film deposition offers the advantage of relatively simple and more mechanically robust construction compared to other methods, as well as allowing precise control of film thickness. Furthermore, this depositional fabrication technique places the layers in intimate thermal contact, providing for three-dimensional conduction and dissipation of the ion-produced heating in the layers, rather than the essentially two-dimensional heat conduction in the discrete foil stack implementation.

  15. SQUIDs vs. Faraday coils for ultlra-low field nuclear magnetic resonance: experimental and simulation comparison

    SciTech Connect

    Matlashov, Andrei N; Espy, Michelle A; Kraus, Robert H; Sayukov, Igor M; Schultz, Larry J; Urbaitis, Algis V; Volegov, Petr L; Wurden, Caroline J

    2010-01-01

    Nuclear magnetic resonance (NMR) methods are widely used in medicine, chemistry and industry. One application area is magnetic resonance imaging or MRI. Recently it has become possible to perform NMR and MRI in ultra-low field (ULF) regime that requires measurement field strengths only of the order of 1 Gauss. These techniques exploit the advantages offered by superconducting quantum interference devices or SQUIDs. Our group at LANL has built SQUID based MRI systems for brain imaging and for liquid explosives detection at airports security checkpoints. The requirement for liquid helium cooling limits potential applications of ULF MRI for liquid identification and security purposes. Our experimental comparative investigation shows that room temperature inductive magnetometers provide enough sensitivity in the 3-10 kHz range and can be used for fast liquid explosives detection based on ULF NMR/MRI technique. We describe an experimental and computer simulation comparison of the world's first multichannel SQUID based and Faraday coils based instruments that are capable of performing ULF MRI for liquids identification.

  16. Fast-Track, One-Step E. coli Detection: A Miniaturized Hydrogel Array Permits Specific Direct PCR and DNA Hybridization while Amplification.

    PubMed

    Beyer, Antje; Pollok, Sibyll; Rudloff, Anne; Cialla-May, Dana; Weber, Karina; Popp, Jürgen

    2016-09-01

    A timesaving and convenient method for bacterial detection based on one-step, one-tube deoxyribonucleic acid (DNA) hybridization on hydrogel array while target gene amplification is described. The hydrogel array is generated by a fast one-pot synthesis, where N,N'-dimethylacrylamide/polyethyleneglycol(PEG1900 )-bisacrylamide mixture polymerizes via radical photoinitiation by visible light within 20 min concomitant with in situ capture probe immobilization. These DNA-functionalized hydrogel droplets arrayed on a planar glass surface are placed in the polymerase chain reaction (PCR) mixture during the thermal amplification cycles. The bacterial cells can be implemented in a direct PCR reaction, omitting the need for prior template DNA extraction. The resulting fluorescence signal is immediately detectable after the end of the PCR (1 h) following one short washing step by microscopy. Therefore a valid signal can be reached within 1.5 h including 10 min for pipetting and placement of the tubes and chips. The performance of this novel hydrogel DNA array was successfully proven with varying cell numbers down to a limit of 10(1) Escherichia coli cells.

  17. Urban development change detection based on Multi-Temporal Satellite Images as a fast tracking approach--a case study of Ahwaz County, southwestern Iran.

    PubMed

    Malmir, Maryam; Zarkesh, Mir Masoud Kheirkhah; Monavari, Seyed Masoud; Jozi, Seyed Ali; Sharifi, Esmail

    2015-03-01

    Rapid land-use/land-cover changes in suburbs of metropolitan cities of Iran have recently caused serious environmental damages. Detection of these changes can be a very important step in urban planning and optimal use of natural resources. Accordingly, the present study was carried out to track land-use/land-cover (LULC) changes of Ahwaz County in southwestern Iran using remote sensing techniques over a period of 26 years, from 1987 to 2013. For this, ISODATA algorithm and Maximum Likelihood were initially used for unsupervised and supervised classifications of the satellite images. The accuracy of the LULC maps was checked by the Kappa Coefficient and the Overall Accuracy methods. As the final step, the LULC changes were detected using the cross-tabulation technique. The obtained results indicated that urban and agricultural areas have been increased about 57.5 and 84.5 %, respectively, from 1987 to 2013. Further, the area of poorly vegetated regions, in the same period, has been decreased to approximately 36 %. The largest land conversion area belongs to the poorly vegetated regions, which have been declined to about 10,371 and 1,334 ha during 1987-2007 and 2007-2013, respectively. Approximately 1,670 and 382 ha of the agricultural lands have also been changed to built-up areas by about 1,670 and 382 ha during the same periods. As a result, it was found that the northwest, southwest, and south of the county were highly subjected to urban development. This would be of great importance for urban planning decision-making faced by the planners of the city in the present and future.

  18. VLA Measurements of Faraday Rotation through a Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Kooi, Jason E.; Fischer, Patrick D.; Buffo, Jacob J.; Spangler, Steven R.

    2015-04-01

    Coronal mass ejections (CMEs) are large scale eruptions of plasma from the Sun that play an important role in space weather. Although CMEs have been an active field of research since their discovery in the 1970s, there is still much to understand. While the plasma structure of a CME is typically modeled as a magnetic flux rope, there is no consensus on the effective trigger that initiates a CME. Other issues include identifying what causes the shift towards non-equilibrium and how CMEs are accelerated after initiation. Faraday rotation (FR) is the rotation of the plane of polarization that results when a linearly polarized signal passes through a magnetized plasma such as a CME. FR observations of a source near the Sun can provide information on the plasma structure of a CME shortly after launch and shed light on the initiation process. We made sensitive Very Large Array (VLA) full-polarization observations in August, 2012, using L band (1 - 2 GHz) frequencies of a “constellation” of radio sources through the solar corona at heliocentric distances that ranged from 6 - 15 solar radii. Because is it difficult to predict whether any given line of sight to a background source will be occulted by a CME, we were only successful in capturing a single CME occultation out of three sessions. In LASCO C3 coronagraph images, the CME clearly occults a few of our sources, the most promising being 0843+1547. The line of sight for this latter source is clearly occulted by the outer loop structure and may also be occulted by the inner cavity most closely associated with the flux rope structure. Preliminary data analysis shows a Faraday rotation transient for 0843+1547; the Faraday rotation measure changes from ~ 0 before CME occultation, to a value of about -12 rad/m^2 before declining after CME passage. In this paper, we discuss the results of these FR observations and their implications in terms of models for the plasma structure of CMEs. This work was supported at the

  19. Faraday rotation as a probe of coronal and astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Mancuso, Salvatore

    Faraday rotation observations of polarized radiation from natural radio sources yield a unique diagnostic of coronal and astrophysical plasmas. We made observations of the radiogalaxy 4C+03.01 seen through the solar corona when the source was at a distance of 8.6 solar radii from the Sun. Nearly continuous polarimetric observations were made on March 28, 1997 with the Very Large Array (VLA) at frequencies of 1465 and 1635 MHz. Dual frequency polarization measurements yield the rotation measure, a quantity that is proportional to the product along the line of sight of the electron density and the line-of-sight component of the magnetic field. We measure a rotation measure of +6.2 +/- 1.0 rad m-2 attributable to the corona. We obtain a weak detection of rotation measure fluctuations which may be due to coronal Alfvén waves and derive model-dependent upper limits to the Alfvén wave flux at the coronal base. We also report dual frequency linear polarization observations of thirteen polarized radio sources made on four days in May 1997 at elongations ranging from 5 to 14 solar radii. A tridimensional model of the solar minimum corona was found to be in excellent agreement with the observed rotation measures and deviations from the values predicted by the model were suggestive of long wavelength coronal Alfvén waves. These observations were also used for detection of high frequency magnetohydrodynamic waves. These waves can be detected through a Faraday screen depolarization mechanism, that is a reduction of the observed degree of linear polarization of an extended polarized source when viewed through a medium in which the Faraday rotation varies randomly. The observations show no detectable depolarization, and rule out some turbulence models. Finally we derive expressions for auto- and cross- correlation functions of the Stokes parameters Q and U of the galactic synchrotron radiation. Fluctuations in the polarization characteristics of the galactic synchrotron

  20. Experimental study of the mutual influence of fibre Faraday elements in a spun-fibre interferometer

    SciTech Connect

    Gubin, V P; Morshnev, S K; Przhiyalkovsky, Ya V; Starostin, N I; Sazonov, A I

    2015-08-31

    An all-spun-fibre linear reflective interferometer with two linked Faraday fibre coils is studied. It is found experimentally that there is mutual influence of Faraday fibre coils in this interferometer. It manifests itself as an additional phase shift of the interferometer response, which depends on the circular birefringence induced by the Faraday effect in both coils. In addition, the interferometer contrast and magneto-optical sensitivity of one of the coils change. A probable physical mechanism of the discovered effect is the distributed coupling of orthogonal polarised waves in the fibre medium, which is caused by fibre bend in the coil. (interferometry)

  1. A two-in-one Faraday rotator mirror exempt of active optical alignment.

    PubMed

    Wan, Qiong; Wan, Zhujun; Liu, Hai; Liu, Deming

    2014-02-10

    A two-in-one Faraday rotator mirror was presented, which functions as two independent Faraday rotation mirrors with a single device. With the introduction of a reflection lens as substitution of the mirror in traditional structure, this device is characterized by exemption of active optical alignment for the designers and manufacturers of Faraday rotator mirrors. A sample was fabricated by passive mechanical assembly. The insertion loss was measured as 0.46 dB/0.50 dB for the two independent ports, respectively.

  2. Permanent magnets for Faraday rotators inspired by the design of the magic sphere.

    PubMed

    Trénec, Gérard; Volondat, William; Cugat, Orphée; Vigué, Jacques

    2011-08-20

    Faraday polarization rotators are commonly used in laser experiments. Most Faraday materials have a nonnegligible absorption, which is a limiting factor for high power laser optical isolators or for intracavity optical diodes. By using a stronger magnetic field and a shorter length of Faraday material, one can obtain the same polarization rotation and a reduced absorption. In this paper, we describe two permanent magnet arrangements that are easy to build and produce magnetic fields up to 1.7 T, substantially more than commonly used. The field homogeneity is largely sufficient for a 30 dB isolation ratio. We finally discuss the prospects for producing even larger fields with permanent magnets.

  3. Inverse energy cascade and emergence of large coherent vortices in turbulence driven by Faraday waves.

    PubMed

    Francois, N; Xia, H; Punzmann, H; Shats, M

    2013-05-10

    We report the generation of large coherent vortices via inverse energy cascade in Faraday wave driven turbulence. The motion of floaters in the Faraday waves is three dimensional, but its horizontal velocity fluctuations show unexpected similarity with two-dimensional turbulence. The inverse cascade is detected by measuring frequency spectra of the Lagrangian velocity, and it is confirmed by computing the third moment of the horizontal velocity fluctuations. This is observed in deep water in a broad range of wavelengths and vertical accelerations. The results broaden the scope of recent findings on Faraday waves in thin layers [A. von Kameke et al., Phys. Rev. Lett. 107, 074502 (2011)].

  4. Electrical control of Faraday rotation at a liquid-liquid interface.

    PubMed

    Marinescu, Monica; Kornyshev, Alexei A; Flatté, Michael E

    2015-01-01

    A theory is developed for the Faraday rotation of light from a monolayer of charged magnetic nanoparticles at an electrified liquid-liquid interface. The polarization fields of neighboring nanoparticles enhance the Faraday rotation. At such interfaces, and for realistic sizes and charges of nanoparticles, their adsorption-desorption can be controlled with a voltage variation<1 V, providing electrovariable Faraday rotation. A calculation based on the Maxwell-Garnett theory predicts that the corresponding redistribution of 40 nm nanoparticles of yttrium iron garnet can switch a cavity with a quality factor larger than 10(4) for light of wavelength 500 nm at normal incidence.

  5. White LED based Faraday current sensor using a quartz wavelength encoder

    NASA Astrophysics Data System (ADS)

    Li, G. D.; Aspey, R. A.; Jones, G. R.

    1999-04-01

    The use of polychromatic light with chromatic modulation has been shown to provide a different approach to Faraday current sensing. In this contribution the use of purely white LEDs along with a quartz rotary encoder and a multiple reflection Faraday sensing element is described for realizing a practical form of a chromatic modulation Faraday current sensor. It is shown that such a sensor embodiment leads to a system sensitivity, for a chromatic system, which is approximately a factor of three times higher than previously reported (0.65 nm A -1 compared with 0.19 nm A -1).

  6. Ramsey-CPT spectrum with the Faraday effect and its application to atomic clocks

    NASA Astrophysics Data System (ADS)

    Tian, Yuan; Tan, Bo-Zhong; Yang, Jing; Zhang, Yi; Gu, Si-Hong

    2015-06-01

    A method that obtains the Ramsey-coherent population trapping (CPT) spectrum with the Faraday effect is investigated. An experiment is implemented to detect the light polarization components generated from the Faraday effect. The experimental results agree with the theoretical calculations based on the Liouville equation. By comparing with the method without using the Faraday effect, the potential of this method for a CPT-based atomic clock is assessed. The results indicate that this method should improve the short-term frequency stability by several times. Project supported by the National Natural Science Foundation of China (Grant Nos. 11304362 and 11204351).

  7. WE-A-17A-10: Fast, Automatic and Accurate Catheter Reconstruction in HDR Brachytherapy Using An Electromagnetic 3D Tracking System

    SciTech Connect

    Poulin, E; Racine, E; Beaulieu, L; Binnekamp, D

    2014-06-15

    Purpose: In high dose rate brachytherapy (HDR-B), actual catheter reconstruction protocols are slow and errors prompt. The purpose of this study was to evaluate the accuracy and robustness of an electromagnetic (EM) tracking system for improved catheter reconstruction in HDR-B protocols. Methods: For this proof-of-principle, a total of 10 catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a Philips-design 18G biopsy needle (used as an EM stylet) and the second generation Aurora Planar Field Generator from Northern Digital Inc. The Aurora EM system exploits alternating current technology and generates 3D points at 40 Hz. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical CT system with a resolution of 0.089 mm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, 5 catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 seconds or less. This would imply that for a typical clinical implant of 17 catheters, the total reconstruction time would be less than 3 minutes. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.92 ± 0.37 mm and 1.74 ± 1.39 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be significantly more accurate (unpaired t-test, p < 0.05). A mean difference of less than 0.5 mm was found between successive EM reconstructions. Conclusion: The EM reconstruction was found to be faster, more accurate and more robust than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators. We would like to disclose that the equipments, used in this study, is coming from a collaboration with Philips Medical.

  8. Faraday Rotation Optical Isolator for 10.6-microm Radiation.

    PubMed

    Jacobs, S D; Teegarden, K J; Ahrenkiel, R K

    1974-10-01

    Measurements that have been performed indicate that hot-pressed ferromagnetic CdCr(2)S(4) would be a useful Faraday optical isolator material for laser systems at 10.6 microm. A large-aperture, liquid-nitrogen-cooled isolator, requiring modest magnetic fields with material of optimum thickness, would provide isolation in excess of 30 dB with insertion loss due to optical absorption in the active element of less than 3 dB. Consideration of its figure of merit indicates that hot-pressed CdCr(2)S(4) could be used as an isolator at 1.06 microm, introducing less than 2 dB insertion loss due to optical absorption at that wavelength.

  9. Faraday isolator stably operating in a wide temperature range

    NASA Astrophysics Data System (ADS)

    Mironov, E. A.; Voitovich, A. V.; Palashov, O. V.

    2016-03-01

    A method of stabilizing Faraday isolator characteristics at varying temperatures is proposed in this letter. The method is based on the use of a magnetic system with an inhomogeneous magnetic field and a magneto-optical element holder made of a material with a high value of thermal expansion coefficient. Changing the rotation angle of the polarization plane of radiation caused by the temperature variation of the magneto-optical element and the temperature dependence of its Verdet constant is compensated by its shifting in the magnetic field. The developed device demonstrates an isolation ratio of more than 40 dB at a temperature range of 25 °C. Estimates show the possibility of providing an isolation ratio of more than 45 dB in a temperature range of 60 °C.

  10. Macroscopic drift current in the inverse Faraday effect

    NASA Astrophysics Data System (ADS)

    Hertel, Riccardo; Fähnle, Manfred

    2015-01-01

    The inverse Faraday effect (IFE) describes the spontaneous magnetization of a conducting or dielectric medium due to irradiation with a circularly polarized electromagnetic wave. The effect has recently been discussed in the context of laser-induced magnetic switching of solids. We analyze analytically the electron dynamics induced by a circularly polarized laser beam within the framework of plasma theory. A macroscopic drift current is obtained, which circulates around the perimeter of the laser beam. The magnetic moment due to this macroscopic current has an opposite sign and half of the magnitude of the magnetic moment that is generated directly by the IFE. This constitutes an important contribution of angular momentum transferred from the wave to the medium and a classical mechanism for the light-induced generation of magnetic fields.

  11. The response function of modulated grid Faraday cup plasma instruments

    NASA Astrophysics Data System (ADS)

    Barnett, A.; Olbert, S.

    Modulated grid Faraday cup plasma analyzers are a very useful tool for making in situ measurements of space plasmas. One of their great attributes is that their simplicity permits their angular response function to be calculated theoretically. An expression is derived for this response function by computing the trajectories of the charged particles inside the cup. The Voyager Plasma Science (PLS) experiment is used as a specific example. Two approximations to the rigorous response function useful for data analysis are discussed. The theoretical formulas were tested by multi-sensor analysis of solar wind data. The tests indicate that the formulas represent the true cup response function for all angles of incidence with a maximum error of only a few percent.

  12. Electrostatic capacitance and Faraday cage behavior of carbon nanotube forests

    SciTech Connect

    Ya'akobovitz, A.; Bedewy, M.; Hart, A. J.

    2015-02-02

    Understanding of the electrostatic properties of carbon nanotube (CNT) forests is essential to enable their integration in microelectronic and micromechanical devices. In this study, we sought to understand how the hierarchical geometry and morphology of CNT forests determines their capacitance. First, we find that at small gaps, solid micropillars have greater capacitance, yet at larger gaps the capacitance of the CNT forests is greater. The surface area of the CNT forest accessible to the electrostatic field was extracted by analysis of the measured capacitance, and, by relating the capacitance to the average density of CNTs in the forest, we find that the penetration depth of the electrostatic field is on the order of several microns. Therefore, CNT forests can behave as a miniature Faraday cage. The unique electrostatic properties of CNT forests could therefore enable their use as long-range proximity sensors and as shielding elements for miniature electronic devices.

  13. Non-destructive Faraday imaging of dynamically controlled ultracold atoms

    SciTech Connect

    Gajdacz, Miroslav; Pedersen, Poul L.; Mørch, Troels; Hilliard, Andrew J.; Arlt, Jan; Sherson, Jacob F.

    2013-08-15

    We describe an easily implementable method for non-destructive measurements of ultracold atomic clouds based on dark field imaging of spatially resolved Faraday rotation. The signal-to-noise ratio is analyzed theoretically and, in the absence of experimental imperfections, the sensitivity limit is found to be identical to other conventional dispersive imaging techniques. The dependence on laser detuning, atomic density, and temperature is characterized in a detailed comparison with theory. Due to low destructiveness, spatially resolved images of the same cloud can be acquired up to 2000 times. The technique is applied to avoid the effect of shot-to-shot fluctuations in atom number calibration, to demonstrate single-run vector magnetic field imaging and single-run spatial imaging of the system's dynamic behavior. This demonstrates that the method is a useful tool for the characterization of static and dynamically changing properties of ultracold atomic clouds.

  14. Aurora on Uranus - A Faraday disc dynamo mechanism

    NASA Astrophysics Data System (ADS)

    Hill, T. W.; Dessler, A. J.; Rassbach, M. E.

    1983-10-01

    A mechanism is proposed whereby the solar wind flowing past the magnetosphere of Uranus causes a Faraday disk dynamo topology to be established and power to be extracted from the kinetic energy of rotation of Uranus. An immediate consequence of this dynamo is the generation of Birkeland currents that flow in and out of the sunlit polar cap with the accompanying production of polar aurora. The power extracted from planetary rotation is calculated as a function of planetary dipole magnetic moment and the ionospheric conductivity of Uranus. For plausible values of ionospheric conductivity, the observed auroral power requires a magnetic moment corresponding to a surface equatorial field of the order of 4 Gauss, slightly larger than the value 1.8 Gauss given by the empirical 'magnetic Bodes law'.

  15. Pseudo Magnetic Faraday and Quantum Hall Effect In Oscillating Graphene

    NASA Astrophysics Data System (ADS)

    Bhagat, Anita; Mullen, Kieran

    When a graphene layer is stressed, the strain changes the phase between sites in a tight binding model of the system. This phase can be viewed as a pseudo-magnetic vector potential. The corresponding pseudo-magnetic field has been experimentally verified in static cases. We examine the case of oscillating graphene ribbons and explore two new effects. The first is to investigate an oscillating pseudo-magnetic field that produces a quantum Hall effect: we calculate the I-V characteristic of an oscillating graphene nanoribbon as a function of frequency, and amplitude in both the oscillations and the applied driving voltage. Second, the time dependent pseudo-magnetic field should produce a pseudo-Faraday effect driving electrons in different valleys in opposite directions. In both cases, we make explicit calculations for experiment. This project was supported in part by the US National Science Foundation under Grant DMR-1310407.

  16. Effects of irregularity anisotropy on Faraday polarization fluctuations

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Nghiem, S. V.; Yoo, C.

    1989-01-01

    The previous model (Lee et al., 1982) of the Faraday polarization fluctuations (FPF) is extended after taking into account the anisotropic nature of the commonly observed, rodlike and sheetlike ionospheric irregularities. Striking effects of irregularity anisotropy are found in the longitudinal radio propagation. However, if the wave propagation angle is not small (say, greater than 5 deg), the effects of irregularity anisotropy on FPF introduced by rodlike irregularities weaken significantly, while those caused by sheetlike irregularities remain prominent. Therefore, under the same ionospheric propagation conditions, sheetlike ionospheric irregularities are more effective than rodlike ionospheric irregularities in causing the FPF of radio waves. It is expected that intense FPF of VHF radio signals can be observed not only near the equatorial anomaly but also in the auroral region.

  17. The response function of modulated grid Faraday cup plasma instruments

    NASA Technical Reports Server (NTRS)

    Barnett, A.; Olbert, S.

    1986-01-01

    Modulated grid Faraday cup plasma analyzers are a very useful tool for making in situ measurements of space plasmas. One of their great attributes is that their simplicity permits their angular response function to be calculated theoretically. An expression is derived for this response function by computing the trajectories of the charged particles inside the cup. The Voyager Plasma Science (PLS) experiment is used as a specific example. Two approximations to the rigorous response function useful for data analysis are discussed. The theoretical formulas were tested by multi-sensor analysis of solar wind data. The tests indicate that the formulas represent the true cup response function for all angles of incidence with a maximum error of only a few percent.

  18. Interplay of air and sand: Faraday heaping unravelled.

    PubMed

    van Gerner, Henk Jan; van der Hoef, Martin A; van der Meer, Devaraj; van der Weele, Ko

    2007-11-01

    We report on numerical simulations of a vibrated granular bed including the effect of the ambient air, generating the famous Faraday heaps known from experiment. A detailed analysis of the forces shows that the heaps are formed and stabilized by the airflow through the bed while the gap between bed and vibrating bottom is growing, confirming the pressure gradient mechanism found experimentally by Thomas and Squires [Phys. Rev. Lett. 81, 574 (1998)], with the addition that the airflow is partly generated by isobars running parallel to the surface of the granular bed. Importantly, the simulations also explain the heaping instability of the initially flat surface and the experimentally observed coarsening of a number of small heaps into a larger one.

  19. Electrostatic capacitance and Faraday cage behavior of carbon nanotube forests

    NASA Astrophysics Data System (ADS)

    Ya'akobovitz, A.; Bedewy, M.; Hart, A. J.

    2015-02-01

    Understanding of the electrostatic properties of carbon nanotube (CNT) forests is essential to enable their integration in microelectronic and micromechanical devices. In this study, we sought to understand how the hierarchical geometry and morphology of CNT forests determines their capacitance. First, we find that at small gaps, solid micropillars have greater capacitance, yet at larger gaps the capacitance of the CNT forests is greater. The surface area of the CNT forest accessible to the electrostatic field was extracted by analysis of the measured capacitance, and, by relating the capacitance to the average density of CNTs in the forest, we find that the penetration depth of the electrostatic field is on the order of several microns. Therefore, CNT forests can behave as a miniature Faraday cage. The unique electrostatic properties of CNT forests could therefore enable their use as long-range proximity sensors and as shielding elements for miniature electronic devices.

  20. THz near-field Faraday imaging in hybrid metamaterials.

    PubMed

    Kumar, Nishant; Strikwerda, Andrew C; Fan, Kebin; Zhang, Xin; Averitt, Richard D; Planken, Paul C M; Adam, Aurèle J L

    2012-05-07

    We report on direct measurements of the magnetic near-field of metamaterial split ring resonators at terahertz frequencies using a magnetic field sensitive material. Specifically, planar split ring resonators are fabricated on a single magneto-optically active terbium gallium garnet crystal. Normally incident terahertz radiation couples to the resonator inducing a magnetic dipole oscillating perpendicular to the crystal surface. Faraday rotation of the polarisation of a near-infrared probe beam directly measures the magnetic near-field with 100 femtosecond temporal resolution and (λ/200) spatial resolution. Numerical simulations suggest that the magnetic field can be enhanced in the plane of the resonator by as much as a factor of 200 compared to the incident field strength. Our results provide a route towards hybrid devices for dynamic magneto-active control of light such as isolators, and highlight the utility of split ring resonators as compact probes of magnetic phenomena in condensed matter.

  1. Sensitive Faraday rotation measurement with auto-balanced photodetection.

    PubMed

    Chang, Chia-Yu; Wang, Likarn; Shy, Jow-Tsong; Lin, Chu-En; Chou, Chien

    2011-06-01

    A magneto-optic polarimetry based on auto-balanced photodetection is investigated. In this experiment, a commercial auto-balanced photoreceiver is adopted to measure the Faraday rotation of air. With a proper setup to utilize its noise cancellation capability, the measurement can be flexible and sensitive. The angular sensitivity is 2.99×10(-8) rad Hz(-1/2), which is about 2.7 times the shot noise limit. The measured Verdet constant of air is +1.39×10(-9) rad G(-1) cm(-1) at 634.8 nm. Significantly we applied a small AC current to induce the magnetic field, so there was no heating in the coil. In addition, a double current modulation scheme was used to demonstrate that there was no zero drift and amplifier instability in the measurement. The possibility of improvement of the angular sensitivity and the potential applications are also discussed.

  2. Giant faraday rotation in conjugated, rod-like molecules

    NASA Astrophysics Data System (ADS)

    Vleugels, Rick; Brullot, Ward; Verbiest, Thierry

    2016-09-01

    Faraday rotation is a magneto-optic phenomenon in which the polarization plane of light is rotated due to magnetically induced circular birefringence. It can be used in a variety of applications such as optical isolators, magnetic field sensors and current sensors. So far, most of the applications use inorganic, paramagnetic materials, which have Verdet constants up to millions of degrees per tesla per meter in the visible spectrum range. They are performant at telecommunication wavelengths, though with smaller Verdet constants, so thicker materials are used. Disadvantages of these materials are their magnetic saturation at low magnetic fields and their strong temperature dependency. Organic, diamagnetic materials on the contrary, saturate at much larger magnetic fields and are less temperature dependent. Furthermore, they also have the advantage of their flexibility and processability. Up to now, magneto-optical research on organic materials has mostly characterized materials with low magneto-optical activity in regions without absorption, but there are some exceptions. Some pi-conjugated polymers have been shown to have very large magneto-optic responses. Furthermore, a mesogenic, organic molecule has been reported with a very high Verdet constant. Conclusive explanations for these large Verdet constants are still lacking, but different possible hypotheses were proposed. In our ongoing search for organic materials with exceptional magneto-optical properties, we examined conjugated, rod-like molecules. Structural, these molecules show close resemblances with the earlier reported mesogenic, organic molecule. We measured giant Verdet constants for thin films of these molecules, reaching values almost as giant as the previous reported mesogenic molecule. These findings shed first preliminary light on a structure-activity relationship for giant Faraday rotation in diamagnetic organic materials.

  3. Graphit-ceramic RF Faraday-thermal shield and plasma limiter

    DOEpatents

    Hwang, David L.; Hosea, Joel C.

    1989-01-01

    The present invention is directed to a process of brazing a ceramic mater to graphite. In particular, the brazing procedure is directed to the production of a novel brazed ceramic graphite product useful as a Faraday shield.

  4. RAPID COMMUNICATION: Vibration immunity and Ampere's circuital law for a near perfect triangular Faraday current sensor

    NASA Astrophysics Data System (ADS)

    Fisher, N. E.; Jackson, D. A.

    1996-08-01

    We report a common-mode rejection scheme for a bulk-optic triangular Faraday current sensor that can eliminate optical noise induced by fibre-link vibration. The sensor's exploitation of Ampere's circuital law is also demonstrated.

  5. The Continuity of Scientific Discovery and Its Communication: The Example of Michael Faraday

    PubMed Central

    Gross, Alan G.

    2009-01-01

    This paper documents the cognitive strategies that led to Faraday’s first significant scientific discovery. For Faraday, discovery is essentially a matter seeing as, of substituting for the eye all possess the eye of analysis all scientists must develop. In the process of making his first significant discovery, Faraday learns to dismiss the magnetic attractions and repulsions he and others had observed; by means of systematic variations in his experimental set-up, he learns to see these motions as circular: it is the first indication that an electro-magnetic field exists. In communicating his discoveries, Faraday, of course, takes into consideration his various audiences’ varying needs and their differences in scientific competence; but whatever his audience, Faraday learns to convey what it feels like to do science, to shift from seeing to seeing as, from sight to insight. PMID:19350498

  6. Ship Tracks

    Atmospheric Science Data Center

    2013-04-19

    article title:  Ship Tracks in a Stratiform Cloud Layer     ... stratocumulus. These striking linear patterns are known as "ship tracks", and are produced when fine particles (also called aerosols) from ... be used with the red filter placed over your left eye. Ship tracks are important examples of aerosol-cloud interactions. They are ...

  7. 45-dB Faraday isolator for 100 W average radiation power

    SciTech Connect

    Andreev, N F; Palashov, O V; Potemkin, A K; Sergeev, Aleksandr M; Khazanov, E A; Reitze, D H

    2000-12-31

    It is demonstrated experimentally that at high average radiation power, the optical isolation in the recently proposed design of a Faraday isolator is substantially higher than in the conventional scheme. The Faraday isolator with the isolation of 45 dB at the radiation power of 100 W is implemented. The data obtained show that a 30-dB isolator for the average laser radiation power of 1 kW can be realised. (laser applications and other topics in quantum electronics)

  8. BROADBAND RADIO POLARIMETRY AND FARADAY ROTATION OF 563 EXTRAGALACTIC RADIO SOURCES

    SciTech Connect

    Anderson, C. S.; Gaensler, B. M.; Feain, I. J.; Franzen, T. M. O.

    2015-12-10

    We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 and 2.0 GHz using data taken with the Australia Telescope Compact Array. We have used rotation-measure synthesis to identify Faraday-complex polarized sources, those objects whose frequency-dependent polarization behavior indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday-complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday-simple polarized sources (sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12% of polarized sources at ∼1′ resolution, but we demonstrate that underlying signal-to-noise limitations mean the true percentage is likely to be significantly higher in the polarized radio source population. We find that the properties of Faraday-complex objects are diverse, but that complexity is most often associated with depolarization of extended radio sources possessing a relatively steep total intensity spectrum. We find an association between Faraday complexity and LOS structure in the Galactic interstellar medium (ISM) and claim that a significant proportion of the Faraday complexity we observe may be generated at interfaces of the ISM associated with ionization fronts near neutral hydrogen structures. Galaxy cluster environments and internally generated Faraday complexity provide possible alternative explanations in some cases.

  9. Broadband Radio Polarimetry and Faraday Rotation of 563 Extragalactic Radio Sources

    NASA Astrophysics Data System (ADS)

    Anderson, C. S.; Gaensler, B. M.; Feain, I. J.; Franzen, T. M. O.

    2015-12-01

    We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 and 2.0 GHz using data taken with the Australia Telescope Compact Array. We have used rotation-measure synthesis to identify Faraday-complex polarized sources, those objects whose frequency-dependent polarization behavior indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday-complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday-simple polarized sources (sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12% of polarized sources at ∼1‧ resolution, but we demonstrate that underlying signal-to-noise limitations mean the true percentage is likely to be significantly higher in the polarized radio source population. We find that the properties of Faraday-complex objects are diverse, but that complexity is most often associated with depolarization of extended radio sources possessing a relatively steep total intensity spectrum. We find an association between Faraday complexity and LOS structure in the Galactic interstellar medium (ISM) and claim that a significant proportion of the Faraday complexity we observe may be generated at interfaces of the ISM associated with ionization fronts near neutral hydrogen structures. Galaxy cluster environments and internally generated Faraday complexity provide possible alternative explanations in some cases.

  10. Geometric Phase Of The Faraday Rotation Of Electromagnetic Waves In Magnetized Plasma

    SciTech Connect

    Jian Liu and Hong Qin

    2011-11-07

    The geometric phase of circularly polarized electromagnetic waves in nonuniform magnetized plasmas is studied theoretically. The variation of the propagation direction of circularly polarized waves results in a geometric phase, which also contributes to the Faraday rotation, in addition to the standard dynamical phase. The origin and properties of the geometric phase is investigated. The in uence of the geometric phase to plasma diagnostics using Faraday rotation is also discussed as an application of the theory.

  11. Effects of Faraday Rotation on Microwave Remote Sensing From Space at L-Band

    NASA Technical Reports Server (NTRS)

    LeVine, D. M.; Kao, M.

    1997-01-01

    The effect of Faraday rotation on the remote sensing of soil moisture from space is investigated using the International Reference Ionosphere (IRI) to obtain electron density profiles and the International Geomagnetic Reference Field (IGRF) to model the magnetic field. With a judicious choice of satellite orbit (6 am, sunsynchronous) the errors caused by ignoring Faraday rotation are less than 1 K at incidence angles less than 40 degrees.

  12. Diode-laser frequency stabilization based on the resonant Faraday effect

    NASA Technical Reports Server (NTRS)

    Wanninger, P.; Valdez, E. C.; Shay, T. M.

    1992-01-01

    The authors present the results of a method for frequency stabilizing laser diodes based on the resonant Faraday effects. A Faraday cell in conjunction with a polarizer crossed with respect to the polarization of the laser diode comprises the intracavity frequency selective element. In this arrangement, a laser pull-in range of 9 A was measured, and the laser operated at a single frequency with a linewidth less than 6 MHz.

  13. Enhanced modified faraday cup for determination of power density distribution of electron beams

    DOEpatents

    Elmer, John W.; Teruya, Alan T.

    2001-01-01

    An improved tomographic technique for determining the power distribution of an electron or ion beam using electron beam profile data acquired by an enhanced modified Faraday cup to create an image of the current density in high and low power ion or electron beams. A refractory metal disk with a number of radially extending slits, one slit being about twice the width of the other slits, is placed above a Faraday cup. The electron or ion beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. The enlarged slit enables orientation of the beam profile with respect to the coordinates of the welding chamber. A second disk having slits therein is positioned below the first slit disk and inside of the Faraday cup and provides a shield to eliminate the majority of secondary electrons and ions from leaving the Faraday cup. Also, a ring is located below the second slit disk to help minimize the amount of secondary electrons and ions from being produced. In addition, a beam trap is located in the Faraday cup to provide even more containment of the electron or ion beam when full beam current is being examined through the center hole of the modified Faraday cup.

  14. Linear theory on temporal instability of megahertz faraday waves for monodisperse microdroplet ejection.

    PubMed

    Tsai, Shirley C; Tsai, Chen S

    2013-08-01

    A linear theory on temporal instability of megahertz Faraday waves for monodisperse microdroplet ejection based on mass conservation and linearized Navier-Stokes equations is presented using the most recently observed micrometer- sized droplet ejection from a millimeter-sized spherical water ball as a specific example. The theory is verified in the experiments utilizing silicon-based multiple-Fourier horn ultrasonic nozzles at megahertz frequency to facilitate temporal instability of the Faraday waves. Specifically, the linear theory not only correctly predicted the Faraday wave frequency and onset threshold of Faraday instability, the effect of viscosity, the dynamics of droplet ejection, but also established the first theoretical formula for the size of the ejected droplets, namely, the droplet diameter equals four-tenths of the Faraday wavelength involved. The high rate of increase in Faraday wave amplitude at megahertz drive frequency subsequent to onset threshold, together with enhanced excitation displacement on the nozzle end face, facilitated by the megahertz multiple Fourier horns in resonance, led to high-rate ejection of micrometer- sized monodisperse droplets (>10(7) droplets/s) at low electrical drive power (<;1 W) with short initiation time (<;0.05 s). This is in stark contrast to the Rayleigh-Plateau instability of a liquid jet, which ejects one droplet at a time. The measured diameters of the droplets ranging from 2.2 to 4.6 μm at 2 to 1 MHz drive frequency fall within the optimum particle size range for pulmonary drug delivery.

  15. How Fast Is Fast?

    ERIC Educational Resources Information Center

    Korn, Abe

    1994-01-01

    Presents an activity that enables students to answer for themselves the question of how fast a body must travel before the nonrelativistic expression must be replaced with the correct relativistic expression by deciding on the accuracy required in describing the kinetic energy of a body. (ZWH)

  16. Faraday's Law, Lenz's Law, and Conservation of Energy

    NASA Astrophysics Data System (ADS)

    Wood, Lowell; Rottmann, Ray; Barrera, Regina

    2003-03-01

    A magnet accelerates upward through a coil and generates an emf that is recorded by a data acquisition system and a computer. Simultaneously, the position of the magnet as a function of time is recorded using a photogate/pulley system. When the circuit is completed by adding an appropriate load resistor, a current that opposes the flux change is generated in the coil. This current causes a magnetic field in the coil that decreases the acceleration of the rising magnet, a fact that is evident from the position versus time data. The energy dissipated by the resistance in the circuit is shown experimentally to equal the loss in mechanical energy of the system to within a few percent, thus demonstrating conservation of energy. The graphs of speed squared versus displacement show the changes in acceleration produced by the interaction of the induced current and the magnet. Students in introductory physics laboratories have successfully performed this experiment and are able to see many relevant features of Faraday's law.

  17. A sensitive Faraday rotation setup using triple modulation

    SciTech Connect

    Phelps, G.; Abney, J.; Broering, M.; Korsch, W.

    2015-07-15

    The utilization of polarized targets in scattering experiments has become a common practice in many major accelerator laboratories. Noble gases are especially suitable for such applications, since they can be easily hyper-polarized using spin exchange or metastable pumping techniques. Polarized helium-3 is a very popular target because it often serves as an effective polarized neutron due to its simple nuclear structure. A favorite cell material to generate and store polarized helium-3 is GE-180, a relatively dense aluminosilicate glass. In this paper, we present a Faraday rotation method, using a new triple modulation technique, where the measurement of the Verdet constants of SF57 flint glass, pyrex glass, and air was tested. The sensitivity obtained shows that this technique may be implemented in future cell wall characterization and thickness measurements. We also discuss the first ever extraction of the Verdet constant of GE-180 glass for four wavelength values of 632 nm, 773 nm, 1500 nm, and 1547 nm, whereupon the expected 1/λ{sup 2} dependence was observed.

  18. A sensitive Faraday rotation setup using triple modulation

    NASA Astrophysics Data System (ADS)

    Phelps, G.; Abney, J.; Broering, M.; Korsch, W.

    2015-07-01

    The utilization of polarized targets in scattering experiments has become a common practice in many major accelerator laboratories. Noble gases are especially suitable for such applications, since they can be easily hyper-polarized using spin exchange or metastable pumping techniques. Polarized helium-3 is a very popular target because it often serves as an effective polarized neutron due to its simple nuclear structure. A favorite cell material to generate and store polarized helium-3 is GE-180, a relatively dense aluminosilicate glass. In this paper, we present a Faraday rotation method, using a new triple modulation technique, where the measurement of the Verdet constants of SF57 flint glass, pyrex glass, and air was tested. The sensitivity obtained shows that this technique may be implemented in future cell wall characterization and thickness measurements. We also discuss the first ever extraction of the Verdet constant of GE-180 glass for four wavelength values of 632 nm, 773 nm, 1500 nm, and 1547 nm, whereupon the expected 1/λ2 dependence was observed.

  19. PROBING THE ROSETTE NEBULA STELLAR BUBBLE WITH FARADAY ROTATION

    SciTech Connect

    Savage, Allison H.; Spangler, Steven R.; Fischer, Patrick D.

    2013-03-01

    We report the results of Faraday rotation measurements of 23 background radio sources whose lines of sight pass through or close to the Rosette Nebula. We made linear polarization measurements with the Karl G. Jansky Very Large Array (VLA) at frequencies of 4.4 GHz, 4.9 GHz, and 7.6 GHz. We find the background Galactic contribution to the rotation measure in this part of the sky to be +147 rad m{sup -2}. Sources whose lines of sight pass through the nebula have an excess rotation measure of 50-750 rad m{sup -2}, which we attribute to the plasma shell of the Rosette Nebula. We consider two simple plasma shell models and how they reproduce the magnitude and sign of the rotation measure, and its dependence on distance from the center of the nebula. These two models represent different modes of interaction of the Rosette Nebula star cluster with the surrounding interstellar medium. Both can reproduce the magnitude and spatial extent of the rotation measure enhancement, given plausible free parameters. We contend that the model based on a stellar bubble more closely reproduces the observed dependence of rotation measure on distance from the center of the nebula.

  20. Homogenized boundary conditions and resonance effects in Faraday cages

    PubMed Central

    Hewitt, I. J.

    2016-01-01

    We present a mathematical study of two-dimensional electrostatic and electromagnetic shielding by a cage of conducting wires (the so-called ‘Faraday cage effect’). Taking the limit as the number of wires in the cage tends to infinity, we use the asymptotic method of multiple scales to derive continuum models for the shielding, involving homogenized boundary conditions on an effective cage boundary. We show how the resulting models depend on key cage parameters such as the size and shape of the wires, and, in the electromagnetic case, on the frequency and polarization of the incident field. In the electromagnetic case, there are resonance effects, whereby at frequencies close to the natural frequencies of the equivalent solid shell, the presence of the cage actually amplifies the incident field, rather than shielding it. By appropriately modifying the continuum model, we calculate the modified resonant frequencies, and their associated peak amplitudes. We discuss applications to radiation containment in microwave ovens and acoustic scattering by perforated shells. PMID:27279775

  1. Plasmaspheric, Faraday and Total Electron Contents, 1977 and 1978.

    DTIC Science & Technology

    1980-12-01

    CdP ~ J I ~~ 1 7,-4 4 U-,’ ’JD- r-’ T --s Iil v -w’s v:C,, . :D’ C)’.,f 7 ’It’j 0’f -i ; 7 *L ’ rc AtA : -r , i’, I**-.~4 .,-~--4 i ----- 1.0 U 7...1-3. i7--. OJ ’ Sx 1 Sr ’*𔃽 c: t _ ’ 1 r;f 173-1 PLASMASPHERIC, FARADAY, AND TOTAL ELECTRON CONTENTS TABLES -1978 1PlLED1L PA(Z BLAUM-X FIIUD...0 U’) L)N CDp 0 O-w41 0.)7O’ RJoItr- C GC’~ (I) ~ - --- -~ - -c nN N N C4 238 I- * c)o Si) nr ’D 0’- Ir - ’ict cI i7 (i 7 Z: C, CC, IsI~

  2. Two-dimensional variational vibroequilibria and Faraday's drops

    NASA Astrophysics Data System (ADS)

    Gavrilyuk, Ivan; Lukovsky, Ivan; Timokha, Alexander

    2004-11-01

    When contacting with acoustically-vibrated structures a fluid volume can take a [time-averaged] geometric shape differing from capillary equilibrium. In accordance with theorems by Beyer et al. (2001) this shape (vibroequilibrium) furnishes a local minimum of a [quasi-potential energy] functional. The variational problem contains five dimensionless parameters evaluating the fluid volume, the wave number of acoustic field in the fluid domain, the contact angle and two newly-introduced numbers (η1, η2) giving relationships between (surface tension, gravitation) and Kapitsa’s vibrational forces/energy. The paper focuses on negligible small wave numbers (incompressible fluid) and two-dimensional flows. Although the variational problem may in some isolated cases have analytical solutions, it requires in general numerical approaches. Numerical examples simulate experiments by Wolf (1969) and Ganiyev et al. (1977) on vibroequilibria in horizontally vibrating tanks. These show that there appear at least two types of stable vibroequilibria associated with symmetric (possible non-connected) and asymmetric surface shapes. The paper represents also numerical results on flattening and vibrostabilisation of a drop hanging beneath a vibrating plate (experiments by Faraday (1831)).

  3. Probing the Rosette Nebula stellar bubble with Faraday rotation

    NASA Astrophysics Data System (ADS)

    Savage, Allison Hainline

    We report the results of Faraday rotation measurements of 23 background radio sources whose lines of sight pass through or close to the Rosette Nebula. We made linear polarization measurements with the Karl G. Jansky Very Large Array (VLA) at frequencies of 4.4 GHz, 4.9 GHz, and 7.6 GHz. We find the background Galactic contribution to the rotation measure in this part of the sky to be +147 rad m-2. Sources whose lines of sight pass through the nebula have an excess rotation measure of 50-750 rad m-2, which we attribute to the plasma shell of the Rosette Nebula. We consider two simple plasma shell models and how they reproduce the magnitude and sign of the rotation measure, and its dependence on distance from the center of the nebula. These two models represent different modes of interaction of the Rosette Nebula star cluster with the surrounding interstellar medium. Both can reproduce the magnitude and spatial extent of the rotation measure enhancement, given plausible free parameters. We contend that the model based on a stellar bubble more closely reproduces the observed dependence of rotation measure on distance from the center of the nebula.

  4. Scaling properties of weakly nonlinear coefficients in the Faraday problem.

    PubMed

    Skeldon, A C; Porter, J

    2011-07-01

    Interesting and exotic surface wave patterns have regularly been observed in the Faraday experiment. Although symmetry arguments provide a qualitative explanation for the selection of some of these patterns (e.g., superlattices), quantitative analysis is hindered by mathematical difficulties inherent in a time-dependent, free-boundary Navier-Stokes problem. More tractable low viscosity approximations are available, but these do not necessarily capture the moderate viscosity regime of the most interesting experiments. Here we focus on weakly nonlinear behavior and compare the scaling results derived from symmetry arguments in the low viscosity limit with the computed coefficients of appropriate amplitude equations using both the full Navier-Stokes equations and a reduced set of partial differential equations due to Zhang and Vinãls. We find the range of viscosities over which one can expect "low viscosity" theories to hold. We also find that there is an optimal viscosity range for locating superlattice patterns experimentally-large enough that the region of parameters giving stable patterns is not impracticably small, yet not so large that crucial resonance effects are washed out. These results help explain some of the discrepancies between theory and experiment.

  5. Hollow cathode lamp based Faraday anomalous dispersion optical filter.

    PubMed

    Pan, Duo; Xue, Xiaobo; Shang, Haosen; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2016-07-15

    The Faraday anomalous dispersion optical filter (FADOF), which has acquired wide applications, is mainly limited to some gaseous elements and low melting-point metals before, for the restriction of the attainable atomic density. In conventional FADOF systems a high atomic density is usually achieved by thermal equilibrium at the saturated vapor pressure, hence for elements with high melting-points a high temperature is required. To avoid this restriction, we propose a scheme of FADOF based on the hollow cathode lamp (HCL), instead of atomic vapor cells. Experimental results in strontium atoms verified this scheme, where a transmission peak corresponding to the (88)Sr (5s(2))(1)S0 - (5s5p)(1)P1 transition (461 nm) is obtained, with a maximum transmittance of 62.5% and a bandwith of 1.19 GHz. The dependence of transmission on magnetic field and HCL discharge current is also studied. Since the state-of-art commercial HCLs cover about 70 elements, this scheme can greatly expand the applications of FADOFs, and the abundant atomic transitions they provide bring the HCL based FADOFs potential applications for frequency stabilization.

  6. Fabrication of a high power Faraday isolator by direct bonding

    NASA Astrophysics Data System (ADS)

    Rothhardt, Carolin; Rekas, Miroslaw; Kalkowski, Gerhard; Haarlammert, Nicoletta; Eberhardt, Ramona; Tünnermann, Andreas

    2013-03-01

    With increasing output power of lasers, absorption in optical components grows larger and demands on heat withdrawal become challenging. We report on the fabrication of a Faraday isolator for high power fiber laser applications (P = 1 kW) at a wavelength of 1080 nm and operation at ambient conditions. We investigate direct bonding of Terbium Gallium Garnet to sapphire disks, to benefit from the good heat spreading properties (having a 6-fold higher thermal conductivity than TGG) at high transparency of the latter. Successful bonding was achieved by extensive cleaning of the plane and smooth surfaces prior to low pressure plasma activation. The surfaces to be bonded were then contacted in a vacuum environment at elevated temperature under axial load. Our measurements show that the bonded interface has no measurable influence on transmission properties and bonded samples are stable for laser output powers of at least 260 W. As compared to a single Terbium Gallium Garnet substrate, wavefront aberrations were significantly decreased by bonding sapphire disks to Terbium Gallium Garnet.

  7. Homogenized boundary conditions and resonance effects in Faraday cages.

    PubMed

    Hewett, D P; Hewitt, I J

    2016-05-01

    We present a mathematical study of two-dimensional electrostatic and electromagnetic shielding by a cage of conducting wires (the so-called 'Faraday cage effect'). Taking the limit as the number of wires in the cage tends to infinity, we use the asymptotic method of multiple scales to derive continuum models for the shielding, involving homogenized boundary conditions on an effective cage boundary. We show how the resulting models depend on key cage parameters such as the size and shape of the wires, and, in the electromagnetic case, on the frequency and polarization of the incident field. In the electromagnetic case, there are resonance effects, whereby at frequencies close to the natural frequencies of the equivalent solid shell, the presence of the cage actually amplifies the incident field, rather than shielding it. By appropriately modifying the continuum model, we calculate the modified resonant frequencies, and their associated peak amplitudes. We discuss applications to radiation containment in microwave ovens and acoustic scattering by perforated shells.

  8. Na-Faraday rotation filtering: The optimal point

    PubMed Central

    Kiefer, Wilhelm; Löw, Robert; Wrachtrup, Jörg; Gerhardt, Ilja

    2014-01-01

    Narrow-band optical filtering is required in many spectroscopy applications to suppress unwanted background light. One example is quantum communication where the fidelity is often limited by the performance of the optical filters. This limitation can be circumvented by utilizing the GHz-wide features of a Doppler broadened atomic gas. The anomalous dispersion of atomic vapours enables spectral filtering. These, so-called, Faraday anomalous dispersion optical filters (FADOFs) can be by far better than any commercial filter in terms of bandwidth, transition edge and peak transmission. We present a theoretical and experimental study on the transmission properties of a sodium vapour based FADOF with the aim to find the best combination of optical rotation and intrinsic loss. The relevant parameters, such as magnetic field, temperature, the related optical depth, and polarization state are discussed. The non-trivial interplay of these quantities defines the net performance of the filter. We determine analytically the optimal working conditions, such as transmission and the signal to background ratio and validate the results experimentally. We find a single global optimum for one specific optical path length of the filter. This can now be applied to spectroscopy, guide star applications, or sensing. PMID:25298251

  9. Theory of Kerr and Faraday rotation in Topological Weyl Semimetals

    NASA Astrophysics Data System (ADS)

    Kargarian, Mehdi; Randeria, Mohit; Trivedi, Nandini

    2015-03-01

    Topological Weyl semimetals are characterized by bulk Dirac nodes separated in momentum space by a distance 2 b and lead to Fermi arcs in the surfaces electronic structure. We calculate the Faraday θF and Kerr θK angles for electromagnetic waves scattered from such a Weyl semimetal using the Kubo formalism. (1) For thin films with electromagnetic radiation incident on a surface without arcs, we show that θK = bd / απ and θF = απ / bd where α is the fine structure constant, and the film thickness d << λ , the wavelength. We further show multiple reflections give rise to giant Kerr rotation, under certain conditions, for a film on a substrate. (2) In the case when the electromagnetic radiation is incident on the surface with arcs, the wave propagating inside the material acquires a longitudinal component of the electric field proportional to b. We discuss the implications of our results for thin films of pyrochlore iridates, and also for the recently discovered Dirac semimetals in a magnetic field. We acknowledge the support of the CEM, an NSF MRSEC, under Grant DMR-1420451.

  10. Homogenized boundary conditions and resonance effects in Faraday cages

    NASA Astrophysics Data System (ADS)

    Hewett, D. P.; Hewitt, I. J.

    2016-05-01

    We present a mathematical study of two-dimensional electrostatic and electromagnetic shielding by a cage of conducting wires (the so-called `Faraday cage effect'). Taking the limit as the number of wires in the cage tends to infinity, we use the asymptotic method of multiple scales to derive continuum models for the shielding, involving homogenized boundary conditions on an effective cage boundary. We show how the resulting models depend on key cage parameters such as the size and shape of the wires, and, in the electromagnetic case, on the frequency and polarization of the incident field. In the electromagnetic case, there are resonance effects, whereby at frequencies close to the natural frequencies of the equivalent solid shell, the presence of the cage actually amplifies the incident field, rather than shielding it. By appropriately modifying the continuum model, we calculate the modified resonant frequencies, and their associated peak amplitudes. We discuss applications to radiation containment in microwave ovens and acoustic scattering by perforated shells.

  11. Hollow cathode lamp based Faraday anomalous dispersion optical filter

    PubMed Central

    Pan, Duo; Xue, Xiaobo; Shang, Haosen; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2016-01-01

    The Faraday anomalous dispersion optical filter (FADOF), which has acquired wide applications, is mainly limited to some gaseous elements and low melting-point metals before, for the restriction of the attainable atomic density. In conventional FADOF systems a high atomic density is usually achieved by thermal equilibrium at the saturated vapor pressure, hence for elements with high melting-points a high temperature is required. To avoid this restriction, we propose a scheme of FADOF based on the hollow cathode lamp (HCL), instead of atomic vapor cells. Experimental results in strontium atoms verified this scheme, where a transmission peak corresponding to the 88Sr (5s2)1S0 − (5s5p)1P1 transition (461 nm) is obtained, with a maximum transmittance of 62.5% and a bandwith of 1.19 GHz. The dependence of transmission on magnetic field and HCL discharge current is also studied. Since the state-of-art commercial HCLs cover about 70 elements, this scheme can greatly expand the applications of FADOFs, and the abundant atomic transitions they provide bring the HCL based FADOFs potential applications for frequency stabilization. PMID:27418112

  12. Faraday rotation echo spectroscopy and detection of quantum fluctuations.

    PubMed

    Chen, Shao-Wen; Liu, Ren-Bao

    2014-04-15

    Central spin decoherence is useful for detecting many-body physics in environments and moreover, the spin echo control can remove the effects of static thermal fluctuations so that the quantum fluctuations are revealed. The central spin decoherence approach, however, is feasible only in some special configurations and often requires uniform coupling between the central spin and individual spins in the baths, which are very challenging in experiments. Here, by making analogue between central spin decoherence and depolarization of photons, we propose a scheme of Faraday rotation echo spectroscopy (FRES) for studying quantum fluctuations in interacting spin systems. The echo control of the photon polarization is realized by flipping the polarization with a birefringence crystal. The FRES, similar to spin echo in magnetic resonance spectroscopy, can suppress the effects of the static magnetic fluctuations and therefore reveal dynamical magnetic fluctuations. We apply the scheme to a rare-earth compound LiHoF4 and calculate the echo signal, which is related to the quantum fluctuations of the system. We observe enhanced signals at the phase boundary. The FRES should be useful for studying quantum fluctuations in a broad range of spin systems, including cold atoms, quantum dots, solid-state impurities, and transparent magnetic materials.

  13. An evolutionary fast-track to biocalcification.

    PubMed

    Jackson, D J; Thiel, V; Wörheide, G

    2010-06-01

    The ability to construct mineralized shells, spicules, spines and skeletons is thought to be a key factor that fuelled the expansion of multicellular animal life during the early Cambrian. The genes and molecular mechanisms that control the process of biomineralization in disparate phyla are gradually being revealed, and it is broadly recognized that an insoluble matrix of proteins, carbohydrates and other organic molecules are required for the initiation, regulation and inhibition of crystal growth. Here, we show that Astrosclera willeyana, a living representative of the now largely extinct stromatoporid sponges (a polyphyletic grade of poriferan bauplan), has apparently bypassed the requirement to evolve many of these mineral-regulating matrix proteins by using the degraded remains of bacteria to seed CaCO(3) crystal growth. Because stromatoporid sponges formed extensive reefs during the Paelozoic and Mesozoic eras (fulfilling the role that stony corals play in modern coral reefs), and fossil evidence suggests that the same process of bacterial skeleton formation occurred in these stromatoporid ancestors, we infer that some ancient reef ecosystems might have been founded on this microbial-metazoan relationship.

  14. FAST TRACK PAPER: Older crust underlies Iceland

    NASA Astrophysics Data System (ADS)

    Foulger, G. R.

    2006-05-01

    The oldest rocks outcropping in northwest Iceland are ~16 Myr old and in east Iceland ~13 Myr. The full plate spreading rate in this region during the Cenozoic has been ~2 cm a-1, and thus these rocks are expected to be separated by ~290 km. They are, however, ~500 km apart. The conclusion is inescapable that an expanse of older crust ~210 km wide underlies Iceland, submerged beneath younger lavas. This conclusion is independent of any considerations regarding spreading ridge migrations, jumps, the simultaneous existence of multiple active ridges, three-dimensionality, or subsidence of the lava pile. Such complexities bear on the distribution and age of the older crust, but not on its existence or its width. If it is entirely oceanic its maximum age is most likely 26-37 Ma. It is at least 150 km in north-south extent, but may taper and extend beneath south Iceland. Part of it might be continental-a southerly extension of the Jan Mayen microcontinent. This older crust contributes significantly to crustal thickness beneath Iceland and the ~40 km local thickness measured seismically is thus probably an overestimate of present-day steady-state crustal production at Iceland.

  15. Certificates: A Fast Track to Careers

    ERIC Educational Resources Information Center

    Torpey, Elka

    2013-01-01

    Certificates are nondegree awards for completing an educational program of study after high school. Typically, students finish these programs to prepare for a specific occupation. And they do so in a relatively short period of time: Most certificates take less than a year to complete, and almost all are designed to take less than 2 years. Among…

  16. Apprenticeship: Fast Track to the Future.

    ERIC Educational Resources Information Center

    Virginia State Dept. of Labor and Industry, Richmond.

    This guide is designed for use by school counselors and students (especially in Virginia), working with parents and teachers to investigate career and educational opportunities. It presents apprenticeship as a beneficial option for high school students, based on four trends: (1) a global economy, advancing technology, and increased competition in…

  17. FAST TRACK: daytime sleepiness in Parkinson's disease.

    PubMed

    Rye, D B; Bliwise, D L; Dihenia, B; Gurecki, P

    2000-03-01

    We describe multiple sleep latency test (MSLT) results in 27 adult patients with idiopathic Parkinson's disease (PD). Pathological sleepiness (i.e. mean sleep latency

  18. Fast Track to College Act of 2011

    THOMAS, 112th Congress

    Sen. Kohl, Herb [D-WI

    2011-01-25

    01/25/2011 Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (text of measure as introduced: CR S225-227) (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  19. Fast Track to College Act of 2009

    THOMAS, 111th Congress

    Sen. Kohl, Herb [D-WI

    2009-03-18

    03/18/2009 Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (text of measure as introduced: CR S3371-3373) (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  20. Fast Track to College Act of 2009

    THOMAS, 111th Congress

    Rep. Kildee, Dale E. [D-MI-5

    2009-03-18

    03/22/2010 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  1. Faraday tomography of the local interstellar medium with LOFAR: Galactic foregrounds towards IC 342

    NASA Astrophysics Data System (ADS)

    Van Eck, C. L.; Haverkorn, M.; Alves, M. I. R.; Beck, R.; de Bruyn, A. G.; Enßlin, T.; Farnes, J. S.; Ferrière, K.; Heald, G.; Horellou, C.; Horneffer, A.; Iacobelli, M.; Jelić, V.; Martí-Vidal, I.; Mulcahy, D. D.; Reich, W.; Röttgering, H. J. A.; Scaife, A. M. M.; Schnitzeler, D. H. F. M.; Sobey, C.; Sridhar, S. S.

    2017-01-01

    Magnetic fields pervade the interstellar medium (ISM), but are difficult to detect and characterize. The new generation of low-frequency radio telescopes, such as the Low Frequency Array (LOFAR: a Square Kilometre Array-low pathfinder), provides advancements in our capability of probing Galactic magnetism through low-frequency polarimetry. Maps of diffuse polarized radio emission and the associated Faraday rotation can be used to infer properties of, and trace structure in, the magnetic fields in the ISM. However, to date very little of the sky has been probed at high angular and Faraday depth resolution. We observed a 5° by 5° region centred on the nearby galaxy IC 342 (ℓ = 138.2°,b = + 10.6°) using the LOFAR high-band antennae in the frequency range 115-178 MHz. We imaged this region at 4'.5x3'.8 resolution and performed Faraday tomography to detect foreground Galactic polarized synchrotron emission separated by Faraday depth (different amounts of Faraday rotation). Our Faraday depth cube shows a rich polarized structure, with up to 30 K of polarized emission at 150 MHz. We clearly detect two polarized features that extend over most of the field, but are clearly separated in Faraday depth. Simulations of the behaviour of the depolarization of Faraday-thick structures at such low frequencies show that such structures would be too strongly depolarized to explain the observations. These structures are therefore rejected as the source of the observed polarized features. Only Faraday thin structures will not be strongly depolarized at low frequencies; producing such structures requires localized variations in the ratio of synchrotron emissivity to Faraday depth per unit distance. Such variations can arise from several physical phenomena, such as a transition between regions of ionized and (mostly) neutral gas. We conclude that the observed polarized emission is Faraday thin, and propose that the emission originates from two mostly neutral clouds in the local ISM

  2. The CDF II eXtremely fast tracker upgrade

    SciTech Connect

    Abulencia, A.; Azzurri, P.; Cochran, E.; Dittmann, J.; Donati, S.; Efron, J.; Erbacher, R.; Errede, D.; Fedorko, I.; Flanagan, G.; Forrest, R.; /Illinois U., Urbana /INFN, Pisa /Pisa U. /Ohio State U. /Baylor U. /UC, Davis /Athens Natl. Capodistrian U. /Purdue U. /Fermilab

    2006-09-01

    The CDF II Extremely Fast Tracker is the trigger track processor which reconstructs charged particle tracks in the transverse plane of the CDF II central outer tracking chamber. The system is now being upgraded to perform a three dimensional track reconstruction. A review of the upgrade is presented here.

  3. Faraday laser using 1.2 km fiber as an extended cavity

    NASA Astrophysics Data System (ADS)

    Tao, Zhiming; Zhang, Xiaogang; Pan, Duo; Chen, Mo; Zhu, Chuanwen; Chen, Jingbiao

    2016-07-01

    We demonstrate a Faraday laser using a 1.2 km fiber as an extended cavity, which provides optical feedback and obtains small free spectrum range (FSR) of 83 kHz, and have succeeded in limiting the laser frequency to a crossover transition {5}2{S}1/2,F=2\\to {5}2{P}3/2,F\\prime =1,3 of the natural 87Rb at 780 nm. The Faraday laser is based on a Faraday anomalous dispersion optical filter (FADOF) with an ultra-narrow bandwidth and the long fiber extended cavity of 1.2 km. The peak transmission assigned to the crossover transition F=2\\to F\\prime =1,3 in the FADOF is 20.5% with an ultra-narrow bandwidth of 29.1 MHz. The Allan deviation of the Faraday laser is around 6.0× {10}-11 in 0.06 to 1 s sampling time. Laser frequency is always kept in the center of the transmitted peak assigned to F=2\\to F\\prime =1,3. The Faraday laser realized here can provide light exactly resonant with an atomic transition used for atom-photon interaction experiments and is insensitive to diode temperature and injection current fluctuations.

  4. Position control of desiccation cracks by memory effect and Faraday waves.

    PubMed

    Nakayama, Hiroshi; Matsuo, Yousuke; Takeshi, Ooshida; Nakahara, Akio

    2013-01-01

    Pattern formation of desiccation cracks on a layer of a calcium carbonate paste is studied experimentally. This paste is known to exhibit a memory effect, which means that a short-time application of horizontal vibration to the fresh paste predetermines the direction of the cracks that are formed after the paste is dried. While the position of the cracks (as opposed to their direction) is still stochastic in the case of horizontal vibration, the present work reports that their positioning is also controllable, at least to some extent, by applying vertical vibration to the paste and imprinting the pattern of Faraday waves, thus breaking the translational symmetry of the system. The experiments show that the cracks tend to appear in the node zones of the Faraday waves: in the case of stripe-patterned Faraday waves, the cracks are formed twice more frequently in the node zones than in the anti-node zones, presumably due to the localized horizontal motion. As a result of this preference of the cracks to the node zones, the memory of the square lattice pattern of Faraday waves makes the cracks run in the oblique direction differing by 45 degrees from the intuitive lattice direction of the Faraday waves.

  5. Diagnostics of the solar corona from comparison between Faraday rotation measurements and magnetohydrodynamic simulations

    SciTech Connect

    Le Chat, G.; Cohen, O.; Kasper, J. C.; Spangler, S. R.

    2014-07-10

    Polarized natural radio sources passing behind the Sun experience Faraday rotation as a consequence of the electron density and magnetic field strength in coronal plasma. Since Faraday rotation is proportional to the product of the density and the component of the magnetic field along the line of sight of the observer, a model is required to interpret the observations and infer coronal structures. Faraday rotation observations have been compared with relatively ad hoc models of the corona. Here for the first time we compare these observations with magnetohydrodynamic (MHD) models of the solar corona driven by measurements of the photospheric magnetic field. We use observations made with the NRAO Very Large Array of 34 polarized radio sources occulted by the solar corona between 5 and 14 solar radii. The measurements were made during 1997 May, and 2005 March and April. We compare the observed Faraday rotation values with values extracted from MHD steady-state simulations of the solar corona. We find that (1) using a synoptic map of the solar magnetic field just one Carrington rotation off produces poorer agreements, meaning that the outer corona changes in the course of one month, even in solar minimum; (2) global MHD models of the solar corona driven by photospheric magnetic field measurements are generally able to reproduce Faraday rotation observations; and (3) some sources show significant disagreement between the model and the observations, which appears to be a function of the proximity of the line of sight to the large-scale heliospheric current sheet.

  6. Online Tracking

    MedlinePlus

    ... used to track you on all kinds of internet-connected devices that have browsers, such as smart phones, tablets, laptop and desktop computers. How does tracking in mobile apps occur? When you access mobile applications, companies don’t have access to ...

  7. Beyond Tracking.

    ERIC Educational Resources Information Center

    Bates, Percy; And Others

    1992-01-01

    On the surface, educational tracking may seem like a useful tool for allowing students to work at their own pace, and to avoid discouraging competition, but abuses of the tracking idea have arisen through biased placement practices that have denied equal access to education for minority students. The articles in this issue explore a number of…

  8. Derailing Tracking.

    ERIC Educational Resources Information Center

    Black, Susan

    1993-01-01

    Reviews recent research on student achievement, self-concept, and curriculum and instruction showing the ineffectiveness of tracking and ability grouping. Certain court rulings show that tracking violates the equal protection clause of the Fourteenth Amendment. Innovative alternatives include cooperative learning, mastery learning, peer tutoring,…

  9. High-dynamic GPS tracking

    NASA Technical Reports Server (NTRS)

    Hinedi, S.; Statman, J. I.

    1988-01-01

    The results of comparing four different frequency estimation schemes in the presence of high dynamics and low carrier-to-noise ratios are given. The comparison is based on measured data from a hardware demonstration. The tested algorithms include a digital phase-locked loop, a cross-product automatic frequency tracking loop, and extended Kalman filter, and finally, a fast Fourier transformation-aided cross-product frequency tracking loop. The tracking algorithms are compared on their frequency error performance and their ability to maintain lock during severe maneuvers at various carrier-to-noise ratios. The measured results are shown to agree with simulation results carried out and reported previously.

  10. Bromine-doped DWNTs: A Molecular Faraday Cage

    NASA Astrophysics Data System (ADS)

    Chen, Gugang; Margine, Roxana; Gupta, Rajeev; Crespi, Vincent; Eklund, Peter; Sumanasekera, Gamini; Bandow, Shunji; Iijima, S.

    2003-03-01

    Raman scattering is used to probe the charge transfer distribution in Bromine-doped double-walled carbon nanotubes (DWNT). Using 1064 nm and 514.5 nm laser excitation we are able to study the charge-transfer sensitive phonons in the inner ( (5,5)) and outer ( (10,10)) tubes of the double-walled pair. The experimental results are compared to our tight binding band structure calculations that include a self-consistent electrostatic term sensitive to the average net charge density on each tube. Upon doping, the nanotube tangential and radial Raman bands from the outer (primary) tubes were observed to shift dramatically to higher frequencies, consistent with a C-C bond contraction driven by the acceptor-doping. The peak intensities of these bands significantly decreased with increasing doping exposure, and they eventually vanished, consistent with a deep depression in the Fermi energy that extinguishes the resonant Raman effect. Interestingly, at the same time, we observed little or no change for the tangential and radial Raman features identified with the inner (secondary) tubes during the bromine doping. Our electronic structure calculations show that the charge distribution between the outer and inner tubes depends on doping level and also, to some extent, on specific tube chirality combinations. In general, in agreement with experiment, the calculations find a very small net charge on the inner tube, consistent with a "Molecular Faraday Effect", e.g., a DWNT of (10, 10)/ (5, 5) configuration that exhibits 0.5 holes/Å total charge transfer, has only 0.04 holes/Å on the inner (secondary) tube.

  11. Effective optical Faraday rotations of semiconductor EuS nanocrystals with paramagnetic transition-metal ions.

    PubMed

    Hasegawa, Yasuchika; Maeda, Masashi; Nakanishi, Takayuki; Doi, Yoshihiro; Hinatsu, Yukio; Fujita, Koji; Tanaka, Katsuhisa; Koizumi, Hitoshi; Fushimi, Koji

    2013-02-20

    Novel EuS nanocrystals containing paramagnetic Mn(II), Co(II), or Fe(II) ions have been reported as advanced semiconductor materials with effective optical rotation under a magnetic field, Faraday rotation. EuS nanocrystals with transition-metal ions, EuS:M nanocrystals, were prepared by the reduction of the Eu(III) dithiocarbamate complex tetraphenylphosphonium tetrakis(diethyldithiocarbamate)europium(III) with transition-metal complexes at 300 °C. The EuS:M nanocrystals thus prepared were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), inductively coupled plasma atomic emission spectroanalysis (ICP-AES), and a superconducting quantum interference device (SQUID) magnetometer. Enhanced Faraday rotations of the EuS:M nanocrystals were observed around 550 nm, and their enhanced spin polarization was estimated using electron paramagnetic resonance (EPR) measurements. In this report, the magneto-optical relationship between the Faraday rotation efficiency and spin polarization is discussed.

  12. Michael Faraday on the Learning of Science and Attitudes of Mind

    NASA Astrophysics Data System (ADS)

    Crawford, Elspeth

    The paper makes use of Michael Faraday's ideas about learning, in particular his thoughts about attitudes to the unknowns of science and the development of an attitude which improves scientific decision-making. An invented scenario involving nursery school children demonstrates some attitudes displayed there. Discussion of the scenario and variation in possible outcomes suggests that Faraday's views are relevant to scientific learning in general. The main thesis of the paper is that it is central to learning in science to acknowledge that there is an inner struggle involved in facing unknowns, and that empathy with the fears and expectations of learners is an essential quality if genuinely scientific thought is to develop. It is suggested, following Faraday, that understanding our own feelings while we teach is a pre-requisite to enabling such empathy and that only then will we be in a position to evaluate accurately whether or not our pupils are thinking scientifically.

  13. Peculiarities of the inverse Faraday effect induced in iron garnet films by femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Kozhaev, M. A.; Chernov, A. I.; Savochkin, I. V.; Kuz'michev, A. N.; Zvezdin, A. K.; Belotelov, V. I.

    2016-12-01

    The inverse Faraday effect in iron garnet films subjected to femtosecond laser pulses is experimentally investigated. It is found that the magnitude of the observed effect depends nonlinearly on the energy of the optical pump pulses, which is in contradiction with the notion that the inverse Faraday effect is linear with respect to the pump energy. Thus, for pump pulses with a central wavelength of 650 nm and an energy density of 1 mJ/cm2, the deviation from a linear dependence is as large as 50%. Analysis of the experimental data demonstrates that the observed behavior is explained by the fact that the optically induced normal component of the magnetization is determined, apart from the field resulting from the inverse Faraday effect, by a decrease in the magnitude of the precessing magnetization under the influence of the femtosecond electromagnetic field.

  14. Faraday rotation measurements by phase-based technique on HL-2A

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Deng, Z. C.; Li, Y. G.; Li, C. Z.; Yi, J.; Li, L. C.; Lui, Y.; Yang, Q. W.; Duan, X. R.; Brower, D. L.; Ding, W. X.

    2012-06-01

    Poloidal magnetic field is a very important physical parameter for the understanding of heating and confinement in tokamak plasmas. One channel of an eight-chord, horizontally-viewing, double-path interferometer system on HL-2A has been modified to include a polarimeter capability in order to measure Faraday rotation. The polarimeter utilizes one phase technique, which is based on a Veron-type HCN laser interferometer and ``Dodel and Kunz''-type polarimeter including a rotating grating to shift the frequency of one probing beam by Δω, and two counter-rotating circularly-polarized probing beams. The Faraday rotation angle can be directly determined by measuring the plasma birefringence. The implementation of this instrument only needs one HCN laser source and one detector to characterize the rotation. The first experimental results have shown that the Faraday rotation angle of less than 1° can be measured with up to 0.1 ms time resolution.

  15. Diagnostics of the Solar corona from Comparison Between Faraday Rotation Measurements and MHD Simulations

    NASA Astrophysics Data System (ADS)

    LE CHAT, G.; Kasper, J. C.; Cohen, O.; Spangler, S.

    2013-05-01

    Faraday rotation observations of natural radio sources allow remote diagnostics of the density and magnetic field of the solar corona. We use linear polarization observations made with the NRAO Very Large Array at frequencies of 1465 and 1665 MHz of 33 polarized radio sources occulted by the solar corona within 5 to 14 solar radii. The measurements were made during May 1997 (Mancuso and Spangler, 2000), March 2005 and april 2005 (Ingleby et al., 2005), corresponding to Carrington rotation number 1922, 1923, 2027 and 2028. We compare the observed Faraday rotation values with values extracted from MHD steady-state simulations of the solar corona using the BATS-R-US model. The simulations are driven by magnetogram data taken at the same time as the observed data. We present the agreement between the model and the Faraday rotation measurements, and we discuss the contraints imposed on models of the quiet corona and CMEs by these observations.

  16. Cavity-enhanced Faraday rotation measurement with auto-balanced photodetection.

    PubMed

    Chang, Chia-Yu; Shy, Jow-Tsong

    2015-10-01

    Optical cavity enhancement for a tiny Faraday rotation is demonstrated with auto-balanced photodetection. This configuration is analyzed using the Jones matrix formalism. The resonant rotation signal is amplified, and thus, the angular sensitivity is improved. In the experiment, the air Faraday rotation is measured with an auto-balanced photoreceiver in single-pass and cavity geometries. The result shows that the measured Faraday rotation in the single-pass geometry is enhanced by a factor of 85 in the cavity geometry, and the sensitivity is improved to 7.54×10(-10)  rad Hz(-1/2), which agrees well with the Jones matrix analysis. With this verification, we propose an AC magnetic sensor whose magnetic sensitivity is expected to achieve 10  pT Hz(-1/2).

  17. Giant Faraday Rotation of High-Order Plasmonic Modes in Graphene-Covered Nanowires.

    PubMed

    Kuzmin, Dmitry A; Bychkov, Igor V; Shavrov, Vladimir G; Temnov, Vasily V

    2016-07-13

    Plasmonic Faraday rotation in nanowires manifests itself in the rotation of the spatial intensity distribution of high-order surface plasmon polariton (SPP) modes around the nanowire axis. Here we predict theoretically the giant Faraday rotation for SPPs propagating on graphene-coated magneto-optically active nanowires. Upon the reversal of the external magnetic field pointing along the nanowire axis some high-order plasmonic modes may be rotated by up to ∼100° on the length scale of about 500 nm at mid-infrared frequencies. Tuning the carrier concentration in graphene by chemical doping or gate voltage allows for controlling SPP-properties and notably the rotation angle of high-order azimuthal modes. Our results open the door to novel plasmonic applications ranging from nanowire-based Faraday isolators to the magnetic control in quantum-optical applications.

  18. Magneto-optical Faraday rotation of semiconductor nanoparticles embedded in dielectric matrices.

    PubMed

    Savchuk, Andriy I; Stolyarchuk, Ihor D; Makoviy, Vitaliy V; Savchuk, Oleksandr A

    2014-04-01

    Faraday rotation has been studied for CdS, CdTe, and CdS:Mn semiconductor nanoparticles synthesized by colloidal chemistry methods. Additionally these materials were prepared in a form of semiconductor nanoparticles embedded in polyvinyl alcohol films. Transmission electron microscopy and atomic force microscopy analyses served as confirmation of nanocrystallinity and estimation of the average size of the nanoparticles. Spectral dependence of the Faraday rotation for the studied nanocrystals and nanocomposites is correlated with a blueshift of the absorption edge due to the confinement effect in zero-dimensional structures. Faraday rotation spectra and their temperature behavior in Mn-doped nanocrystals demonstrates peculiarities, which are associated with s, p-d exchange interaction between Mn²⁺ ions and band carriers in diluted magnetic semiconductor nanostructures.

  19. Faraday tomography: a new, three-dimensional probe of the interstellar magnetic field

    NASA Astrophysics Data System (ADS)

    Ferrière, Katia

    2016-11-01

    Much of our present observational knowledge of the interstellar magnetic field of our Galaxy comes from two different sources, both of which involve mechanisms operating at radio wavelengths: the first one is the Faraday rotation of linearly-polarized radio waves propagating through the magneto-ionic interstellar medium, and the second one is the diffuse synchrotron emission from our Galaxy. I will review what these two classical probes have taught us about the strength, the direction/orientation, and the spatial distribution of the interstellar magnetic field. I will then present a recent method, known as Faraday tomography or rotation measure synthesis, which relies on a combination of Faraday rotation and synchrotron emission and which makes it possible to probe the interstellar magnetic field in three dimensions.

  20. Dispersion of Electric-Field-Induced Faraday Effect in Magnetoelectric Cr2O3

    NASA Astrophysics Data System (ADS)

    Wang, Junlei; Binek, Christian

    2016-03-01

    The frequency dependence of the electric-field-induced magneto-optical Faraday effect is investigated in the magnetoelectric antiferromagnet chromia. Two electrically induced Faraday signals superimpose in proportion to the linear magnetoelectric susceptibility α and the antiferromagnetic order parameter η . The relative strength of these contributions is determined by the frequency of the probing light and can be tuned between extreme characteristics following the temperature dependence of α or η . The frequency dependence is analyzed in terms of electric dipole transitions of perturbed Cr3 + crystal-field states. The results allow us to measure voltage-controlled selection, isothermal switching, and temperature dependence of η in a tabletop setup. The voltage-specific Faraday rotation is independent of the sample thickness, making the method scalable and versatile down to the limit of dielectric breakdown.

  1. Stochastic Faraday rotation induced by the electric current fluctuations in nanosystems

    NASA Astrophysics Data System (ADS)

    Smirnov, D. S.; Glazov, M. M.

    2017-01-01

    We demonstrate theoretically that in gyrotropic semiconductors and semiconductor nanosystems the Brownian motion of electrons results in temporal fluctuations of the polarization plane of light passing through or reflected from the structure, i.e., in stochastic Faraday or Kerr rotation effects. The theory of the effects is developed for a number of prominent gyrotropic systems such as bulk tellurium, ensembles of chiral carbon nanotubes, and GaAs-based quantum wells of different crystallographic orientations. We show that the power spectrum of these fluctuations in thermal equilibrium is proportional to the a c conductivity of the system. We evaluate contributions resulting from the fluctuations of the electric current, as well as of spin, valley polarization, and the spin current to the noise of the Faraday/Kerr rotation. Hence all-optical measurements of the Faraday and Kerr rotation noise provide an access to the transport properties of the semiconductor systems.

  2. Rover tracks

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Tracks made by the Sojourner rover are visible in this image, taken by one of the cameras aboard Sojourner on Sol 3. The tracks represent the rover maneuvering towards the rock dubbed 'Barnacle Bill.' The rover, having exited the lander via the rear ramp, first traveled towards the right portion of the image, and then moved forward towards the left where Barnacle Bill sits. The fact that the rover was making defined tracks indicates that the soil is made up of particles on a micron scale.

    Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration.

  3. Faraday Effect sensor redressed by Nd2Fe14B biasing magnetic film.

    PubMed

    Jiao, Xinbing; Nguyen, Truong Giang; Qian, Bo; Jiang, Chunping; Ma, Lixin

    2012-01-16

    A Faraday Effect sensor with Nd(2)Fe(14)B biasing magnetic film was described. Ta/Nd(2)Fe(14)B/Ta films were grown by magnetron sputtering method. The magnetic domain in the sensor with the Nd(2)Fe(14)B biasing magnetic film can persist its distribution. The average linearity error of Faraday Effect sensor with biasing magnetic film decreased from 1.42% to 0.125% compared with non-biasing magnetic film, and the measurement range increased from 820 Oe to 900 Oe.

  4. Polarization-induced noise in a fiber-optic Michelson interferometer with Faraday rotator mirror elements

    NASA Astrophysics Data System (ADS)

    Ferreira, L. A.; Santos, J. L.; Farahi, F.

    1995-10-01

    Faraday rotator mirror elements have been used in a number of applications as compensators for induced birefringence in retracing paths. In interferometric systems, such as the fiber-optic Michelson interferometer, this approach proved to be useful in providing maximum fringe visibility and insensitivity to the polarization state of light injected into the interferometer. However, it is found that, when the characteristics of the fiber coupler depend on the polarization state of the input beam, the efficiency of the Faraday mirror elements is limited. Theoretical analysis and experimental results in support of this statement are presented.

  5. Collinearity alignment of probe beams in a laser-based Faraday effect diagnostica)

    NASA Astrophysics Data System (ADS)

    Lin, L.; Ding, W. X.; Brower, D. L.

    2012-10-01

    Two counter-rotating circularly polarized beams are used in a laser-based polarimetry diagnostic providing a phase measurement of the Faraday effect. Collinearity of these beams is a key issue that affects measurement accuracy. Spatial offset from even small misalignment induces systematic error due to density gradient and path length difference. Here, we report an alignment technique using a rotating dielectric wedge, which is capable of reducing spatial offset of two probe beams below 0.1 mm for beams with 40 mm diameter. With optimized alignment, 0.05° Faraday effect fluctuations associated with global tearing modes are resolved with an uncertainty below 0.01°.

  6. Theoretical model for frequency locking a diode laser with a Faraday cell

    NASA Technical Reports Server (NTRS)

    Wanninger, P.; Shay, T. M.

    1992-01-01

    A new method was developed for frequency locking a diode lasers, called 'the Faraday anomalous dispersion optical transmitter (FADOT) laser locking', which is much simpler than other known locking schemes. The FADOT laser locking method uses commercial laser diodes with no antireflection coatings, an atomic Faraday cell with a single polarizer, and an output coupler to form a compound cavity. The FADOT method is vibration insensitive and exhibits minimal thermal expansion effects. The system has a frequency pull in the range of 443.2 GHz (9 A). The method has potential applications in optical communication, remote sensing, and pumping laser excited optical filters.

  7. The Rb 780-nanometer Faraday anomalous dispersion optical filter: Theory and experiment

    NASA Technical Reports Server (NTRS)

    Yin, B.; Alvarez, L. S.; Shay, T. M.

    1994-01-01

    The Faraday anomalous dispersion optical filter may provide ultra-high background noise rejection for free-space laser communications systems. The theoretical model for the filter is reported. The experimental measurements and their comparison with theoretical results are discussed. The results show that the filter can provide a 56-dB solar background noise rejection with about a 2-GHz transmission bandwidth and no image degradation. To further increase the background noise rejection, a composite Zeeman and Faraday anomalous dispersion optical filter is designed and experimentally demonstrated.

  8. VizieR Online Data Catalog: Faraday tomography of foreground towards IC342 (Van Eck+, 2017)

    NASA Astrophysics Data System (ADS)

    van Eck, C. L.; Haverkorn, M.; Alves, M. I. R.; Beck, R.; de Bruyn, A. G.; Ensslin, T.; Farnes, J. S.; Ferriere, K.; Heald, G.; Horellou, C.; Horneffer, A.; Iacobelli, M.; Jelic, V.; Marti-Vidal, I.; Mulcahy, D. D.; Reich, W.; Rottgering, H. J. A.; Scaife, A. M. M.; Schnitzeler, D. H. F. M.; Sobey, C.; Sridhar, S. S.

    2016-11-01

    The Faraday depth cube of the IC342 field in polarized intensity, produced from LOFAR HBA observations as part of LOFAR proposal LC0_043. The cube is approximately 5x5 degrees in size, with 4-arcmin resolution, and covers Faraday depths from -25 to +25rad/m2. The detailed specifications are given in the table and in the FITS header. Selected frames from this cubes are shown in the paper in Figures 2 through 5. An extended description of the data processing leading to this cube is included in the paper. (2 data files).

  9. Graphite-ceramic rf Faraday-thermal shield and plasma limiter

    DOEpatents

    Hwang, D.L.Q.; Hosea, J.C.

    1983-05-05

    The present invention is directed to a brazing procedure for joining a ceramic or glass material (e.g., Al/sub 2/O/sub 3/ or Macor) to graphite. In particular, the present invention is directed to a novel brazing procedure for the production of a brazed ceramic graphite product useful as a Faraday shield. The brazed ceramic graphite Faraday shield of the present invention may be used in Magnetic Fusion Devices (e.g., Princeton Large Torus Tokamak) or other high temperature resistant apparatus.

  10. Polarization-induced noise in a fiber-optic Michelson interferometer with Faraday rotator mirror elements.

    PubMed

    Ferreira, L A; Santos, J L; Farahi, F

    1995-10-01

    Faraday rotator mirror elements have been used in a number of applications as compensators for induced birefringence in retracing paths. In interferometric systems, such as the fiber-optic Michelson interferometer, this approach proved to be useful in providing maximum fringe visibility and insensitivity to the polarization state of light injected into the interferometer. However, it is found that, when the characteristics of the fiber coupler depend on the polarization state of the input beam, the efficiency of the Faraday mirror elements is limited. Theoretical analysis and experimental results in support of this statement are presented.

  11. Strong interband Faraday rotation in 3D topological insulator Bi2Se3.

    PubMed

    Ohnoutek, L; Hakl, M; Veis, M; Piot, B A; Faugeras, C; Martinez, G; Yakushev, M V; Martin, R W; Drašar, Č; Materna, A; Strzelecka, G; Hruban, A; Potemski, M; Orlita, M

    2016-01-11

    The Faraday effect is a representative magneto-optical phenomenon, resulting from the transfer of angular momentum between interacting light and matter in which time-reversal symmetry has been broken by an externally applied magnetic field. Here we report on the Faraday rotation induced in the prominent 3D topological insulator Bi2Se3 due to bulk interband excitations. The origin of this non-resonant effect, extraordinarily strong among other non-magnetic materials, is traced back to the specific Dirac-type Hamiltonian for Bi2Se3, which implies that electrons and holes in this material closely resemble relativistic particles with a non-zero rest mass.

  12. Interaction of vortex lattice with ultrasound and the acoustic Faraday effect

    SciTech Connect

    Dominguez, D.; Bulaevskii, L.; Ivlev, B.; Maley, M.; Bishop, A.R. |

    1995-03-27

    The interaction of sound with the vortex lattice is considered for high-{ital T}{sub {ital c}} superconductors, taking into account pinning and electrodynamic forces between vortices and crystal displacements. At low temperatures the Magnus force results in the acoustic Faraday effect; the velocity of sound propagating along the magnetic field depends on the polarization. This effect is linear in the Magnus force and magnetic field in crystals with equivalent {ital a} and {ital b} axes for a field parallel to the {ital c} axis. In the thermally activated flux flow regime, the Faraday effect is caused by electric and magnetic fields induced by vortices and acting on ions.

  13. Patterns beyond Faraday waves: observation of parametric crossover from Faraday instabilities to the formation of vortex lattices in open dual fluid strata

    NASA Astrophysics Data System (ADS)

    Ohlin, Kjell; Berggren, Karl Fredrik

    2016-07-01

    Faraday first characterised the behaviour of a fluid in a container subjected to vertical periodic oscillations. His study pertaining to hydrodynamic instability, the ‘Faraday instability’, has catalysed a myriad of experimental, theoretical, and numerical studies shedding light on the mechanisms responsible for the transition of a system at rest to a new state of well-ordered vibrational patterns at fixed frequencies. Here we study dual strata in a shallow vessel containing distilled water and high-viscosity lubrication oil on top of it. At elevated driving power, beyond the Faraday instability, the top stratum is found to ‘freeze’ into a rigid pattern with maxima and minima. At the same time there is a dynamic crossover into a new state in the form of a lattice of recirculating vortices in the lower layer containing the water. Instrumentation and the physics behind are analysed in a phenomenological way together with a basic heuristic modelling of the wave field. The study, which is based on relatively low-budget equipment, stems from related art projects that have evolved over the years. The study is of value within basic research as well as in education, especially as more advanced collective project work in e.g. engineering physics, where it invites further studies of pattern formation, the emergence of vortex lattices and complexity.

  14. Features of collisionless turbulence in the intracluster medium from simulated Faraday rotation maps - II. The effects of instabilities feedback

    NASA Astrophysics Data System (ADS)

    Santos-Lima, R.; de Gouveia Dal Pino, E. M.; Falceta-Gonçalves, D. A.; Nakwacki, M. S.; Kowal, G.

    2017-03-01

    Statistical analysis of Faraday rotation measure (RM) maps of the intracluster medium (ICM) of galaxy clusters provides a unique tool to evaluate some spatial features of the magnetic fields there. Its combination with numerical simulations of magnetohydrodynamic (MHD) turbulence allows the diagnosis of the ICM turbulence. Being the ICM plasma weakly collisional, the thermal velocity distribution of the particles naturally develops anisotropies as a consequence of the large-scale motions and the conservation of the magnetic moment of the charged particles. A previous study (Paper I) analysed the impact of large-scale thermal anisotropy on the statistics of RM maps synthesized from simulations of turbulence; these simulations employed a collisionless MHD model that considered a tensor pressure with uniform anisotropy. In this work, we extend that analysis to a collisionless MHD model in which the thermal anisotropy develops according to the conservation of the magnetic moment of the thermal particles. We also consider the effect of anisotropy relaxation caused by the microscale mirror and firehose instabilities. We show that if the relaxation rate is fast enough to keep the anisotropy limited by the threshold values of the instabilities, the dispersion and power spectrum of the RM maps are indistinguishable from those obtained from collisional MHD. Otherwise, there is a reduction in the dispersion and steepening of the power spectrum of the RM maps (compared to the collisional case). Considering the first scenario, the use of collisional MHD simulations for modelling the RM statistics in the ICM becomes better justified.

  15. Magnetooptical Faraday and Light-Scattering Diagnostics of Laser Plasma in Leopard Laser Facility at UNR/NTF

    NASA Astrophysics Data System (ADS)

    Sarkisov, G. S.; Yates, K.; Ivanov, V. V.; Sotnikov, V. I.; Yasin, E.; Wiewior, P.; Astanovitsky, A.; Chaly, O.; Kindel, J.

    2009-11-01

    Laser plasma of the solid target on Leopard Laser Facility at University of Nevada Reno was investigated using polarimetry, interferometry and laser-scattering diagnostics. 50 TW Nd:glass Leopard laser operates on 1056 nm wavelength, 10 J energy and 1ns/400 fs pulse width. Power flux on a target surface varied from 10^14 to 10^19W/cm^2 with 20 μm focus spot from off-axis parabola. The diagnostic of spontaneous magnetic fields in laser plasma was carried out using three-channel polarinterferometer with Faraday, shadow and interferogram channels. Ultrafast two-frame shadowgrams/interferograms with two probing beams with orthogonal polarizations were used for investigation of fast moving plasma phenomena (jets, ionization front propagation). Continuous 1W green DPSS-laser with external modulation was used for light scattering experiments for investigation of the late-time micro-particles generation in laser plasma with expected large charge number of the grain Z ˜ 100-1000.

  16. Detection of a Coherent Magnetic Field in the Magellanic Bridge through Faraday Rotation

    NASA Astrophysics Data System (ADS)

    Kaczmarek, J. F.; Purcell, C. R.; Gaensler, B. M.; McClure-Griffiths, N. M.; Stevens, J.

    2017-01-01

    We present an investigation into the magnetism of the Magellanic Bridge, carried out through the observation of Faraday rotation towards 167 polarized extragalactic radio sources spanning the continuous frequency range of 1.3 - 3.1 GHz with the Australia Telescope Compact Array. Comparing measured Faraday depth values of sources `on' and `off' the Bridge, we find that the two populations are implicitly different. Assuming that this difference in populations is due to a coherent field in the Magellanic Bridge, the observed Faraday depths indicate a median line-of-sight coherent magnetic-field strength of B∥ ≃ 0.3 μG directed uniformly away from us. Motivated by the varying magnitude of Faraday depths of sources on the Bridge, we speculate that the coherent field observed in the Bridge is a consequence of the coherent magnetic fields from the Large and SMCs being pulled into the tidal feature. This is the first observation of a coherent magnetic field spanning the entirety of the Magellanic Bridge and we argue that this is a direct probe of a `pan-Magellanic' field.

  17. If Maxwell Had Worked between Ampere and Faraday: An Historical Fable with a Pedagogical Moral.

    ERIC Educational Resources Information Center

    Jammer, Max; Stachel, John

    1980-01-01

    Describes a new pedagogical approach to electromagnetic theory, in which the displacement current and the Galilean relativity principle are introduced before discussion of the Faraday induction term. Rationale for the alternate order of introducing these concepts and laws is explained, relative to their historical development. (CS)

  18. Permanent-magnet Faraday isolator with the field intensity of 25 kOe

    SciTech Connect

    Mironov, E A; Snetkov, I L; Voitovich, A V; Palashov, O V

    2013-08-31

    A Faraday isolator with a single magneto-optical element is constructed and experimentally tested. It provides the isolation ratio of 30 dB at an average laser radiation power of 650 W. These parameters are obtained by increasing the field intensity in the magnetic system of the isolator and employing a low-absorption magneto-optical element. (elements of laser devices)

  19. In-vacuum optical isolation changes by heating in a Faraday isolator.

    PubMed

    Acernese, Fausto; Alshourbagy, Mohamed; Amico, Paolo; Antonucci, Federica; Aoudia, S; Astone, P; Avino, Saverio; Ballardin, G; Baggio, L; Barone, Fabrizio; Barsotti, Lisa; Barsuglia, Matteo; Bauer, Th S; Bigotta, Stefano; Birindelli, Simona; Bizouard, Marie-Anne; Boccara, Albert-Claude; Bondu, François; Bosi, Leone; Braccini, Stefano; Bradaschia, Carlo; Brillet, Alain; Brisson, Violette; Buskulic, Damir; Cagnoli, G; Calloni, Enrico; Campagna, Enrico; Carbognani, Franco; Carbone, L; Cavalier, Fabien; Cavalieri, R; Cella, G; Cesarini, E; Chassande-Mottin, E; Chatterji, S; Cleva, F; Coccia, E; Corda, C; Corsi, A; Cottone, F; Coulon, J-P; Cuoco, E; D'Antonio, S; Dari, A; Dattilo, V; Davier, M; De Rosa, R; Del Prete, M; Di Fiore, L; Di Lieto, A; Di Paolo Emilio, M; Di Virgilio, A; Evans, M; Fafone, V; Ferrante, I; Fidecaro, F; Fiori, I; Flaminio, R; Fournier, J-D; Frasca, S; Frasconi, F; Gammaitoni, L; Garufi, F; Genin, E; Gennai, A; Giazotto, A; Giordano, L; Granata, V; Greverie, C; Grosjean, D; Guidi, G; Hamdani, S; Hebri, S; Heitmann, H; Hello, P; Huet, D; La Penna, P; Laval, M; Leroy, N; Letendre, N; Lopez, B; Lorenzini, M; Loriette, V; Losurdo, G; Mackowski, J-M; Majorana, E; Man, N; Mantovani, M; Marchesoni, F; Marion, F; Marque, J; Martelli, F; Masserot, A; Menzinger, F; Milano, L; Minenkov, Y; Moins, C; Morgado, N; Mosca, S; Mours, B; Neri, I; Nocera, F; Pagliaroli, G; Palomba, C; Paoletti, F; Pardi, S; Pasqualetti, A; Passaquieti, R; Passuello, D; Persichetti, G; Piergiovanni, F; Pinard, L; Poggiani, R; Punturo, M; Puppo, P; Rabaste, O; Rapagnani, P; Regimbau, T; Remillieux, A; Ricci, F; Ricciardi, I; Rocchi, A; Rolland, L; Romano, R; Ruggi, P; Russo, G; Sentenac, D; Solimeno, S; Swinkels, B L; Tarallo, M; Terenzi, R; Toncelli, A; Tonelli, M; Tournefier, E; Travasso, F; Vajente, G; van den Brand, J F J; van der Putten, S; Verkindt, D; Vetrano, F; Viceré, A; Vinet, J-Y; Vocca, H; Yvert, M

    2008-11-01

    We describe a model evaluating changes in the optical isolation of a Faraday isolator when passing from air to vacuum in terms of different thermal effects in the crystal. The changes are particularly significant in the crystal thermal lensing (refraction index and thermal expansion) and in its Verdet constant and can be ascribed to the less efficient convection cooling of the magneto-optic crystal of the Faraday isolator. An isolation decrease by a factor of 10 is experimentally observed in a Faraday isolator that is used in a gravitational wave experiment (Virgo) with a 10 W input laser when going from air to vacuum. A finite element model simulation reproduces with a great accuracy the experimental data measured on Virgo and on a test bench. A first set of measurements of the thermal lensing has been used to characterize the losses of the crystal, which depend on the sample. The isolation factor measured on Virgo confirms the simulation model and the absorption losses of 0.0016 +/- 0.0002/cm for the TGG magneto-optic crystal used in the Faraday isolator.

  20. Michael Faraday on the Learning of Science and Attitudes of Mind.

    ERIC Educational Resources Information Center

    Crawford, Elspeth

    1998-01-01

    Makes use of Michael Faraday's ideas on learning, focusing on his attitudes toward the unknowns of science and the development of an attitude that improves scientific decision making. This approach acknowledges that there is an inner struggle involved in facing unknowns. (DDR)

  1. A Bright Spark: Open Teaching of Science Using Faraday's Lectures on Candles

    ERIC Educational Resources Information Center

    Walker, Mark; Groger, Martin; Schutler, Kirsten; Mosler, Bernd

    2008-01-01

    As well as being a founding father of modern chemistry and physics Michael Faraday was also a skilled lecturer, able to explain scientific principles and ideas simply and concisely to nonscientific audiences. However science didactics today emphasizes the use of open and student-centered methods of teaching in which students find and develop…

  2. Faraday Rotation Measure Synthesis of Intermediate Redshift Quasars as a Probe of Intervening Matter

    NASA Astrophysics Data System (ADS)

    Kim, Kwang Seong; Lilly, Simon J.; Miniati, Francesco; Bernet, Martin L.; Beck, Rainer; O'Sullivan, Shane P.; Gaensler, Bryan M.

    2016-10-01

    There is evidence that magnetized material along the line of sight to distant quasars is detectable in the polarization properties of the background sources. The polarization properties appear to be correlated with the presence of intervening Mg ii absorption, which is thought to arise in outflowing material from star forming galaxies. In order to investigate this further, we have obtained high spectral resolution polarization measurements, with the Very Large Array and the Australia Telescope Compact Array, of a set of 49 unresolved quasars for which we have high quality optical spectra. These enable us to produce a Faraday Depth spectrum for each source, using Rotation Measure (RM) Synthesis. Our new independent radio data confirms that interveners are strongly associated with depolarization. We characterize the complexity of the Faraday Depth spectrum using a number of parameters and show how these are related, or not, to the depolarization and to the presence of Mg ii absorption along the line of sight. We argue that complexity and structure in the Faraday Depth distribution likely arise from both intervening material and intrinsically to the background source and attempt to separate these. We find that the strong radio depolarization effects associated with intervening material at redshifts out to z≈ 1 arise from inhomogeneous Faraday screens producing a dispersion in RM across individual sources of around 10 rad m-2. This is likely produced by disordered fields with strengths of at least 3 μG.

  3. Thermooptics of magnetoactive media: Faraday isolators for high average power lasers

    NASA Astrophysics Data System (ADS)

    Khazanov, E. A.

    2016-09-01

    The Faraday isolator, one of the key high-power laser elements, provides optical isolation between a master oscillator and a power amplifier or between a laser and its target, for example, a gravitational wave detector interferometer. However, the absorbed radiation inevitably heats the magnetoactive medium and leads to thermally induced polarization and phase distortions in the laser beam. This self-action process limits the use of Faraday isolators in high average power lasers. A unique property of magnetoactive medium thermooptics is that parasitic thermal effects arise on the background of circular birefringence rather than in an isotropic medium. Also, even insignificant polarization distortions of the radiation result in a worse isolation ratio, which is the key characteristic of the Faraday isolator. All possible laser beam distortions are analyzed for their deteriorating effect on the Faraday isolator parameters. The mechanisms responsible for and key physical parameters associated with different kinds of distortions are identified and discussed. Methods for compensating and suppressing parasitic thermal effects are described in detail, the published experimental data are systematized, and avenues for further research are discussed based on the results achieved.

  4. Shot-noise-limited optical Faraday polarimetry with enhanced laser noise cancelling

    SciTech Connect

    Li, Jiaming; Luo, Le Carvell, Jeff; Cheng, Ruihua; Lai, Tianshu Wang, Zixin

    2014-03-14

    We present a shot-noise-limited measurement of optical Faraday rotations with sub-ten-nanoradian angular sensitivity. This extremely high sensitivity is achieved by using electronic laser noise cancelling and phase sensitive detection. Specially, an electronic laser noise canceller with a common mode rejection ratio of over 100 dB was designed and built for enhanced laser noise cancelling. By measuring the Faraday rotation of ambient air, we demonstrate an angular sensitivity of up to 9.0×10{sup −9} rad/√(Hz), which is limited only by the shot-noise of the photocurrent of the detector. To date, this is the highest angular sensitivity ever reported for Faraday polarimeters in the absence of cavity enhancement. The measured Verdet constant of ambient air, 1.93(3)×10{sup −9}rad/(G cm) at 633 nm wavelength, agrees extremely well with the earlier experiments using high finesse optical cavities. Further, we demonstrate the applications of this sensitive technique in materials science by measuring the Faraday effect of an ultrathin iron film.

  5. Far off-resonance laser frequency stabilization using multipass cells in Faraday rotation spectroscopy.

    PubMed

    Quan, Wei; Li, Yang; Li, Rujie; Shang, Huining; Fang, Zishan; Qin, Jie; Wan, Shuangai

    2016-04-01

    We propose a far off-resonance laser frequency stabilization method by using multipass cells in Rb Faraday rotation spectroscopy. Based on the detuning equation, if multipass cells with several meters optical path length are used in the conventional Faraday spectroscopy, the detuning of the lock point can be extended much further from the alkali metal resonance. A plate beam splitter was used to generate two different Faraday signals at the same time. The transmitted optical path length was L=50  mm and the reflected optical path length was 2L=100  mm. When the optical path length doubled, the detuning of the lock points moved further away from the atomic resonance. The temperature dependence of the detuning of the lock point was also analyzed. A temperature-insensitive lock point was found near resonance when the cell temperature was between 110°C and 130°C. We achieved an rms fluctuation of 0.9 MHz/23 h at a detuning of 0.5 GHz. A frequency drift of 16 MHz/h at a detuning of -5.6  GHz and 4 MHz/h at a detuning of -5.2  GHz were also obtained for the transmitted and reflected light Faraday signal.

  6. Conditions for the Validity of Faraday's Law of Induction and Their Experimental Confirmation

    ERIC Educational Resources Information Center

    Lopez-Ramos, A.; Menendez, J. R.; Pique, C.

    2008-01-01

    This paper, as its main didactic objective, shows the conditions needed for the validity of Faraday's law of induction. Inadequate comprehension of these conditions has given rise to several paradoxes about the issue; some are analysed and solved in this paper in the light of the theoretical deduction of the induction law. Furthermore, an…

  7. Theory of Kerr and Faraday rotations and linear dichroism in Topological Weyl Semimetals.

    PubMed

    Kargarian, Mehdi; Randeria, Mohit; Trivedi, Nandini

    2015-08-03

    We consider the electromagnetic response of a topological Weyl semimetal (TWS) with a pair of Weyl nodes in the bulk and corresponding Fermi arcs in the surface Brillouin zone. We compute the frequency-dependent complex conductivities σαβ(ω) and also take into account the modification of Maxwell equations by the topological θ-term to obtain the Kerr and Faraday rotations in a variety of geometries. For TWS films thinner than the wavelength, the Kerr and Faraday rotations, determined by the separation between Weyl nodes, are significantly larger than in topological insulators. In thicker films, the Kerr and Faraday angles can be enhanced by choice of film thickness and substrate refractive index. We show that, for radiation incident on a surface with Fermi arcs, there is no Kerr or Faraday rotation but the electric field develops a longitudinal component inside the TWS, and there is linear dichroism signal. Our results have implications for probing the TWS phase in various experimental systems.

  8. All-Fiber Optical Magnetic Field Sensor Based on Faraday Rotation

    SciTech Connect

    Sun, L.; Jiang, S.; Marciante, J.R.

    2010-06-18

    An all-fiber optical magnetic field sensor with a sensitivity of 0.49 rad/T is demonstrated. It consists of a fiber Faraday rotator (56-wt.%-terbium–doped silica fiber) and a fiber polarizer (Corning SP1060 fiber).

  9. Design and construction of a Faraday cup for measurement of small electronic currents

    NASA Technical Reports Server (NTRS)

    Veyssiere, A.

    1985-01-01

    The design of a device to measure and integrate very small currents generated by the impact of a charged particle beam upon a Faraday cut is described. The main component is a graphite block capable of stopping practically all the incident changes. The associated electronic apparatus required to measure better than 10/13 ampere with a precision of 10/0 is described.

  10. Exploring Faraday's Law of Electrolysis Using Zinc-Air Batteries with Current Regulative Diodes

    ERIC Educational Resources Information Center

    Kamata, Masahiro; Paku, Miei

    2007-01-01

    Current regulative diodes (CRDs) are applied to develop new educational experiments on Faraday's law by using a zinc-air battery (PR2330) and a resistor to discharge it. The results concluded that the combination of zinc-air batteries and the CRD array is simpler, less expensive, and quantitative and gives accurate data.

  11. Web life: Faraday's Cage Is Where You Put Schrödinger's Cat

    NASA Astrophysics Data System (ADS)

    2012-01-01

    Faraday's Cage Is Where You Put Schrödinger's Cat (FCIWYPSC) is a blog written by Cherish Bauer-Reich, who is pursuing a PhD in geophysics at the University of Minnesota while also working part-time as a research engineer at North Dakota State University (NDSU), some 250 miles away.

  12. A New Method for Analyzing Near-Field Faraday Probe Data in Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Huang, Wensheng; Shastry, Rohit; Herman, Daniel A.; Soulas, George C.; Kamhawi, Hani

    2013-01-01

    This paper presents a new method for analyzing near-field Faraday probe data obtained from Hall thrusters. Traditional methods spawned from far-field Faraday probe analysis rely on assumptions that are not applicable to near-field Faraday probe data. In particular, arbitrary choices for the point of origin and limits of integration have made interpretation of the results difficult. The new method, called iterative pathfinding, uses the evolution of the near-field plume with distance to provide feedback for determining the location of the point of origin. Although still susceptible to the choice of integration limits, this method presents a systematic approach to determining the origin point for calculating the divergence angle. The iterative pathfinding method is applied to near-field Faraday probe data taken in a previous study from the NASA-300M and NASA-457Mv2 Hall thrusters. Since these two thrusters use centrally mounted cathodes the current density associated with the cathode plume is removed before applying iterative pathfinding. A procedure is presented for removing the cathode plume. The results of the analysis are compared to far-field probe analysis results. This paper ends with checks on the validity of the new method and discussions on the implications of the results.

  13. A New Method for Analyzing Near-Field Faraday Probe Data in Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Huang, Wensheng; Shastry, Rohit; Herman, Daniel A.; Soulas, George C.; Kamhawi, Hani

    2013-01-01

    This paper presents a new method for analyzing near-field Faraday probe data obtained from Hall thrusters. Traditional methods spawned from far-field Faraday probe analysis rely on assumptions that are not applicable to near-field Faraday probe data. In particular, arbitrary choices for the point of origin and limits of integration have made interpretation of the results difficult. The new method, called iterative pathfinding, uses the evolution of the near-field plume with distance to provide feedback for determining the location of the point of origin. Although still susceptible to the choice of integration limits, this method presents a systematic approach to determining the origin point for calculating the divergence angle. The iterative pathfinding method is applied to near-field Faraday probe data taken in a previous study from the NASA-300M and NASA-457Mv2 Hall thrusters. Since these two thrusters use centrally mounted cathodes, the current density associated with the cathode plume is removed before applying iterative pathfinding. A procedure is presented for removing the cathode plume. The results of the analysis are compared to far-field probe analysis results. This paper ends with checks on the validity of the new method and discussions on the implications of the results.

  14. Parsec-scale Faraday rotation and polarization of 20 active galactic nuclei jets

    NASA Astrophysics Data System (ADS)

    Kravchenko, E. V.; Kovalev, Y. Y.; Sokolovsky, K. V.

    2017-01-01

    We perform polarimetry analysis of 20 active galactic nuclei (AGN) jets using the Very Long Baseline Array (VLBA) at 1.4, 1.6, 2.2, 2.4, 4.6, 5.0, 8.1, 8.4, and 15.4 GHz. The study allowed us to investigate linearly polarized properties of the jets at parsec-scales: distribution of the Faraday rotation measure (RM) and fractional polarization along the jets, Faraday effects and structure of Faraday-corrected polarization images. Wavelength-dependence of the fractional polarization and polarization angle is consistent with external Faraday rotation, while some sources show internal rotation. The RM changes along the jets, systematically increasing its value towards synchrotron self-absorbed cores at shorter wavelengths. The highest core RM reaches 16,900 rad m-2 in the source rest frame for the quasar 0952+179, suggesting the presence of highly magnetized, dense media in these regions. The typical RM of transparent jet regions has values of an order of a hundred rad m-2 . Significant transverse rotation measure gradients are observed in seven sources. The magnetic field in the Faraday screen has no preferred orientation, and is observed to be random or regular from source to source. Half of the sources show evidence for the helical magnetic fields in their rotating magnetoionic media. At the same time jets themselves contain large-scale, ordered magnetic fields and tend to align its direction with the jet flow. The observed variety of polarized signatures can be explained by a model of spine-sheath jet structure.

  15. Fast Reactors

    NASA Astrophysics Data System (ADS)

    Esposito, S.; Pisanti, O.

    The following sections are included: * Elementary Considerations * The Integral Equation to the Neutron Distribution * The Critical Size for a Fast Reactor * Supercritical Reactors * Problems and Exercises

  16. A fast meteor detection algorithm

    NASA Astrophysics Data System (ADS)

    Gural, P.

    2016-01-01

    A low latency meteor detection algorithm for use with fast steering mirrors had been previously developed to track and telescopically follow meteors in real-time (Gural, 2007). It has been rewritten as a generic clustering and tracking software module for meteor detection that meets both the demanding throughput requirements of a Raspberry Pi while also maintaining a high probability of detection. The software interface is generalized to work with various forms of front-end video pre-processing approaches and provides a rich product set of parameterized line detection metrics. Discussion will include the Maximum Temporal Pixel (MTP) compression technique as a fast thresholding option for feeding the detection module, the detection algorithm trade for maximum processing throughput, details on the clustering and tracking methodology, processing products, performance metrics, and a general interface description.

  17. Simplified fast neutron dosimeter

    DOEpatents

    Sohrabi, Mehdi

    1979-01-01

    Direct fast-neutron-induced recoil and alpha particle tracks in polycarbonate films may be enlarged for direct visual observation and automated counting procedures employing electrochemical etching techniques. Electrochemical etching is, for example, carried out in a 28% KOH solution at room temperature by applying a 2000 V peak-to-peak voltage at 1 kHz frequency. Such recoil particle amplification can be used for the detection of wide neutron dose ranges from 1 mrad. to 1000 rads. or higher, if desired.

  18. A Faraday rotation search for magnetic fields in quasar damped Ly alpha absorption systems

    NASA Technical Reports Server (NTRS)

    Oren, Abraham L.; Wolfe, Arthur M.

    1995-01-01

    We present the results of a Faraday rotation survey of 61 radio-bright QSOs conducted at the National Radio Astronomy Observatory (NRAO) Very Large Array (VLA). The Galactic contribution to the Faraday rotation is estimated and subtracted to determine the extragalactic rotation measure (RRM) for each source. Eleven of these QSOs are known to exhibit damped Ly alpha absorption. The rate of incidence of significant Faraday rotation of these 11 sources is compared to the remaining 50 and is found to be higher at the 99.8% confidence level. However, as this is based upon only two detections of Faraday rotation in the damped Ly alpha sample, the result is only tentative. If the two detections in the damped Ly alpha sample are dug to the absorbing systems, then the inferred rotation measure induced by these systems is roughly 250 rad/sq m. The two detections were for the two lowest redshift absorbers in the sample. We find that a rotation measure of 250 rad/sq m would have gone undetected for any other absorber in the damped Ly alpha sample due to the 1/(1 + 2) squared dilution of the observed RRM with redshift. Thus the data are consistent with, but do not prove, the hypothesis that Faraday rotation is a generic property of damped Ly alpha absorbers. We do not confirm the suggestion that the amplitude of RRMs increases with redshift. Rather, the data are consistent with no redshift evolution. We find that the uncertainty in the estimation of the Galactic rotation measure (GRM) is a more serious problem than previously realized for extra-galactic Faraday rotation studies of QSO absorbers. A careful analysis of current methods for estimating GRM indicate that it can be determined to an accuracy of about 15 - 20 rad/sq m. Previous studies underestimated this uncertainty by more than a factor of 2. Due to this uncertainty, rotation measures such as we suspect are associated with damped Ly alpha absorption systems can only be detected at redshifts less than z approximately

  19. Giant Faraday rotation in Bi(x)Ce(3-x)Fe5O12 epitaxial garnet films.

    PubMed

    Chandra Sekhar, M; Singh, Mahi R; Basu, Shantanu; Pinnepalli, Sai

    2012-04-23

    Thin films of Bi(x)Ce(3-x)Fe(5)O(12) with x = 0.7 and 0.8 compositions were prepared by using pulsed laser deposition. We investigated the effects of processing parameters used to fabricate these films by measuring various physical properties such as X-ray diffraction, transmittance, magnetization and Faraday rotation. In this study, we propose a phase diagram which provides a suitable window for the deposition of Bi(x)Ce(3-x)Fe(5)O(12) epitaxial films. We have also observed a giant Faraday rotation of 1-1.10 degree/µm in our optimized films. The measured Faraday rotation value is 1.6 and 50 times larger than that of CeYIG and YIG respectively. A theoretical model has been proposed for Faraday rotation based on density matrix method and an excellent agreement between experiment and theory is found.

  20. MOJAVE: MONITORING OF JETS IN ACTIVE GALACTIC NUCLEI WITH VLBA EXPERIMENTS. VIII. FARADAY ROTATION IN PARSEC-SCALE AGN JETS

    SciTech Connect

    Hovatta, Talvikki; Lister, Matthew L.; Aller, Margo F.; Aller, Hugh D.; Homan, Daniel C.; Kovalev, Yuri Y.

    2012-10-01

    We report observations of Faraday rotation measures for a sample of 191 extragalactic radio jets observed within the MOJAVE program. Multifrequency Very Long Baseline Array observations were carried out over 12 epochs in 2006 at four frequencies between 8 and 15 GHz. We detect parsec-scale Faraday rotation measures in 149 sources and find the quasars to have larger rotation measures on average than BL Lac objects. The median core rotation measures are significantly higher than in the jet components. This is especially true for quasars where we detect a significant negative correlation between the magnitude of the rotation measure and the de-projected distance from the core. We perform detailed simulations of the observational errors of total intensity, polarization, and Faraday rotation, and concentrate on the errors of transverse Faraday rotation measure gradients in unresolved jets. Our simulations show that the finite image restoring beam size has a significant effect on the observed rotation measure gradients, and spurious gradients can occur due to noise in the data if the jet is less than two beams wide in polarization. We detect significant transverse rotation measure gradients in four sources (0923+392, 1226+023, 2230+114, and 2251+158). In 1226+023 the rotation measure is for the first time seen to change sign from positive to negative over the transverse cuts, which supports the presence of a helical magnetic field in the jet. In this source we also detect variations in the jet rotation measure over a timescale of three months, which are difficult to explain with external Faraday screens and suggest internal Faraday rotation. By comparing fractional polarization changes in jet components between the four frequency bands to depolarization models, we find that an external purely random Faraday screen viewed through only a few lines of sight can explain most of our polarization observations, but in some sources, such as 1226+023 and 2251+158, internal

  1. Useful Equations for Calculating the Induced Voltage Inside a Faraday Cage that has been Struck by Lightning

    SciTech Connect

    JORGENSON, ROY E.; WARNE, LARRY K.

    2001-09-01

    One of the tasks performed routinely by the Electromagnetics and Plasma Physics Analysis Department at Sandia National Laboratories is analyzing the effects of direct-strike lightning on Faraday cages that protect sensitive items. The Faraday cages analyzed thus far have many features in common. This report is an attempt to collect equations and other information that have been routinely used in the past in order to facilitate future analysis.

  2. Consecutive pedestrian tracking in large scale space

    NASA Astrophysics Data System (ADS)

    Lan, Jinpeng; Xu, Yi

    2016-09-01

    Pedestrian tracking is an important and meaningful part of the computer vision topic. Given the position of pedestrian in the first frame, our goal is to automatically determine the accurate position of the target pedestrian in every frame that follows. Current tracking methods show good performance in short-term tracking. However, there are still some open problems in real scenes, e.g. pedestrian re-identification under multi-camera surveillance and pedestrian tracking under occlusions. In our paper, we proposed an efficient method for consecutive tracking, which can deal with the challenging view changes and occlusions. Proposed tracker consists of short-time tracking mechanism and consecutive tracking mechanism. The consecutive tracking mechanism will be activated while the target pedestrian is under occlusion or changes dramatically in appearance. In consecutive tracking mechanism, proposed algorithm will detect the target pedestrian using a coarse but fast feature as first level classifier and a fine feature as the last level classifier. After regaining the accurate position of target pedestrian, the appearance model of the target pedestrian will be updated as historical information and the short-time tracking mechanism will be activated again to continue tracking the target pedestrian. Experimental results show that the proposed method can handle hard cases and achieve higher success rate than the current existing methods.

  3. Fast CRCs

    DTIC Science & Technology

    2009-10-01

    Detecting Codes: General Theory and Their Application in Feedback Communication Systems. Kluwer Academic, 1995. [8] D.E. Knuth , The Art of Computer ... computation . Index Terms—Fast CRC, low-complexity CRC, checksum, error-detection code, Hamming code, period of polynomial, fast software implementation...simulations, and performance analysis of systems and networks. CRC implementation in software is desirable, because many computers do not have hardware

  4. Faraday-Active Fabry-Perot Resonator: Transmission, Reflection, and Emissivity

    NASA Technical Reports Server (NTRS)

    Liptuga, Anatoliy; Morozhenko, Vasyl; Pipa, Viktor; Venger, Evgen; Kostiuk, Theodor

    2011-01-01

    The propagation of light within a semiconductor Faraday-active Fabry-Perot resonator (FAFR) is investigated theoretically and experimentally. It is shown that an external magnetic field radically changes the angular and spectral characteristics of transmission, reflection and emissivity of the resonator not only for polarized, but also for unpolarized light. Suppression of interference patterns and phase inversion of the interference extrema were observed in both monochromatic and polychromatic light. The investigations were carried out for the plane-parallel plates of n-InAs in the spectral range of free charge carrier absorption. The results can be used to create new controllable optical and spectroscopic devices for investigation of Faraday-active material properties and for control of parameters of plane-parallel layers and structures.

  5. Probing the gravitational Faraday rotation using quasar X-ray microlensing.

    PubMed

    Chen, Bin

    2015-11-17

    The effect of gravitational Faraday rotation was predicted in the 1950s, but there is currently no practical method for measuring this effect. Measuring this effect is important because it will provide new evidence for correctness of general relativity, in particular, in the strong field limit. We predict that the observed degree and angle of the X-ray polarization of a cosmologically distant quasar microlensed by the random star field in a foreground galaxy or cluster lens vary rapidly and concurrently with flux during caustic-crossing events using the first simulation of quasar X-ray microlensing polarization light curves. Therefore, it is possible to detect gravitational Faraday rotation by monitoring the X-ray polarization of gravitationally microlensed quasars. Detecting this effect will also confirm the strong gravity nature of quasar X-ray emission.

  6. Faraday-effect polarimeter-interferometer system for current density measurement on EAST

    NASA Astrophysics Data System (ADS)

    Liu, H. Q.; Jie, Y. X.; Ding, W. X.; Brower, D. L.; Zou, Z. Y.; Li, W. M.; Wang, Z. X.; Qian, J. P.; Yang, Y.; Zeng, L.; Lan, T.; Wei, X. C.; Li, G. S.; Hu, L. Q.; Wan, B. N.

    2014-11-01

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 1016 m-2 (˜2°), and the Faraday rotation angle rms phase noise is <0.1°.

  7. Faraday effect of polycrystalline bismuth iron garnet thin film prepared by mist chemical vapor deposition method

    NASA Astrophysics Data System (ADS)

    Yao, Situ; Kamakura, Ryosuke; Murai, Shunsuke; Fujita, Koji; Tanaka, Katsuhisa

    2017-01-01

    We have synthesized polycrystalline thin film composed of a single phase of metastable bismuth iron garnet, Bi3Fe5O12, on a fused silica substrate, one of the most widely utilized substrates in the solid-state electronics, by using mist chemical vapor deposition (mist CVD) method. The phase purity and stoichiometry are confirmed by X-ray diffraction and Rutherford backscattering spectrometry. The resultant thin film shows a small surface roughness of 3.251 nm. The saturation magnetization at room temperature is 1200 G, and the Faraday rotation angle at 633 nm reaches -5.2 deg/μm. Both the magnetization and the Faraday rotation angles are somewhat higher than those of polycrystalline BIG thin films prepared by other methods.

  8. Plasmonically enhanced Faraday effect in metal and ferrite nanoparticles composite precipitated inside glass.

    PubMed

    Nakashima, Seisuke; Sugioka, Koji; Tanaka, Katsuhisa; Shimizu, Masahiro; Shimotsuma, Yasuhiko; Miura, Kiyotaka; Midorikawa, Katsumi; Mukai, Kohki

    2012-12-17

    Using femtosecond laser irradiation and subsequent annealing, nanocomposite structures composed of spinel-type ferrimagnetic nanoparticles (NPs) and plasmonic metallic NPs have been formed space-selectively within glass doped with both α-Fe(2)O(3) and Al. The Faraday rotation spectra exhibit a distinct negative peak at around 400 nm, suggesting that the ferrimagnetic Faraday response is enhanced by the localized surface plasmon resonance (LSPR) due to metallic Al NPs. At the interfaces in the nanocomposites, the ferrimagnetism of magnetite NPs is directly coupled with the plasmon in the Al NPs. The control of the resonance wavelength of the magneto-optical peaks, namely, the size of plasmonic NPs has been demonstrated by changing the irradiation or annealing conditions.

  9. Limits to the Magnetic Field in the Planetary Nebula NGC 246 from Faraday Rotation

    NASA Astrophysics Data System (ADS)

    Rodríguez, L. F.; Carrasco-González, C.; Cantó, J.; Pasetto, A.; Raga, A. C.; Tafoya, D.

    2017-04-01

    We present radio continuum observations of the linearly polarized extragalactic source J0047-1150, whose line of sight traverses the galactic planetary nebula NGC 246. We determine the position angle of the electric vector at seven frequencies between 1.3 and 1.8 GHz, finding no evidence of Faraday rotation and setting a 4-σ upper limit to the rotation measure of 9.6 rad m-2, which implies an upper limit to the average line-of-sight component of the magnetic field in NGC 246 of 1.3 μG. However, we show that the rotation measure across a source with a dipolar magnetic field morphology practically cancels out. Therefore, if the magnetic field has this morphology, the local values of the magnetic field in NGC 246 could be much larger and will not be evident in a Faraday rotation experiment.

  10. Probing the gravitational Faraday rotation using quasar X-ray microlensing

    PubMed Central

    Chen, Bin

    2015-01-01

    The effect of gravitational Faraday rotation was predicted in the 1950s, but there is currently no practical method for measuring this effect. Measuring this effect is important because it will provide new evidence for correctness of general relativity, in particular, in the strong field limit. We predict that the observed degree and angle of the X-ray polarization of a cosmologically distant quasar microlensed by the random star field in a foreground galaxy or cluster lens vary rapidly and concurrently with flux during caustic-crossing events using the first simulation of quasar X-ray microlensing polarization light curves. Therefore, it is possible to detect gravitational Faraday rotation by monitoring the X-ray polarization of gravitationally microlensed quasars. Detecting this effect will also confirm the strong gravity nature of quasar X-ray emission. PMID:26574051

  11. Interaction between Faraday rotation and Cotton-Mouton effects in polarimetry modeling for NSTX

    SciTech Connect

    Zhang, J.; Crocker, N. A.; Carter, T. A.; Kubota, S.; Peebles, W. A.

    2010-10-15

    The evolution of electromagnetic wave polarization is modeled for propagation in the major radial direction in the National Spherical Torus Experiment with retroreflection from the center stack of the vacuum vessel. This modeling illustrates that the Cotton-Mouton effect-elliptization due to the magnetic field perpendicular to the propagation direction-is shown to be strongly weighted to the high-field region of the plasma. An interaction between the Faraday rotation and Cotton-Mouton effects is also clearly identified. Elliptization occurs when the wave polarization direction is neither parallel nor perpendicular to the local transverse magnetic field. Since Faraday rotation modifies the polarization direction during propagation, it must also affect the resultant elliptization. The Cotton-Mouton effect also intrinsically results in rotation of the polarization direction, but this effect is less significant in the plasma conditions modeled. The interaction increases at longer wavelength and complicates interpretation of polarimetry measurements.

  12. Faraday effect improvement by Dy3+-doping of terbium gallium garnet single crystal

    NASA Astrophysics Data System (ADS)

    Chen, Zhe; Yang, Lei; Hang, Yin; Wang, Xiangyong

    2016-01-01

    Highly transparent Dy3+-doped terbium gallium garnet (TGG) single crystal was grown by Czochralski (Cz) method. Phase composition of the crystal was tested by XRD measurements. The distribution coefficient of Dy3+ in the crystal was obtained. The optical and magneto-optical properties were analyzed in detail, and magnetic properties of the Dy3+-TGG crystal were studied. The paramagnetic behavior is observed down to 10 K. The as-grown crystal exhibited high optical transmittance, particularly in the visible region. The Faraday rotation was investigated over visible and near-infrared regions (VIS-NIR) at room temperature. The Verdet constants increase at measured wavelengths and high thermal stability was found in Dy3+-doped TGG, as compared to the properties of pure TGG, indicating that Dy3+-doped crystals are preferable for magneto-active materials used in Faraday devices at VIS-NIR wavelengths.

  13. Terahertz spectroscopy on Faraday and Kerr rotations in a quantum anomalous Hall state

    PubMed Central

    Okada, Ken N.; Takahashi, Youtarou; Mogi, Masataka; Yoshimi, Ryutaro; Tsukazaki, Atsushi; Takahashi, Kei S.; Ogawa, Naoki; Kawasaki, Masashi; Tokura, Yoshinori

    2016-01-01

    Electrodynamic responses from three-dimensional topological insulators are characterized by the universal magnetoelectric term constituent of the Lagrangian formalism. The quantized magnetoelectric coupling, which is generally referred to as topological magnetoelectric effect, has been predicted to induce exotic phenomena including the universal low-energy magneto-optical effects. Here we report the experimental indication of the topological magnetoelectric effect, which is exemplified by magneto-optical Faraday and Kerr rotations in the quantum anomalous Hall states of magnetic topological insulator surfaces by terahertz magneto-optics. The universal relation composed of the observed Faraday and Kerr rotation angles but not of any material parameters (for example, dielectric constant and magnetic susceptibility) well exhibits the trajectory towards the fine structure constant in the quantized limit. PMID:27436710

  14. Progress Towards the Detection of Faraday Rotation on Spin Polarized 3He

    NASA Astrophysics Data System (ADS)

    Abney, Josh; Broering, Mark; Korsch, Wolfgang

    2016-03-01

    Off-resonance Faraday rotation can offer a new method to monitor the nuclear spin polarization of a dense 3He target and gain access to new information about the magnetic polarizability of the 3He nucleus. The interaction of the polarization state of light with the nuclear spin of the helium atom is very weak and has never been detected. A sensitive triple modulation technique has been developed which can detect the expected rotation angle on the order of 100 nrad. Once a Faraday rotation signal is observed, the next step is to separate the magnetic and electric contributions to the rotation by utilizing their different frequency dependencies. Recent studies involved optimizing several parameters which impact 3He target polarization. Progress towards detecting nuclear spin optical rotation on 3He will be reported. This research is supported by DOE Grant DE-FG02-99ER41101.

  15. Universal Faraday Rotation in HgTe Wells with Critical Thickness.

    PubMed

    Shuvaev, A; Dziom, V; Kvon, Z D; Mikhailov, N N; Pimenov, A

    2016-09-09

    The universal value of the Faraday rotation angle close to the fine structure constant (α≈1/137) is experimentally observed in thin HgTe quantum wells with a thickness on the border between trivial insulating and the topologically nontrivial Dirac phases. The quantized value of the Faraday angle remains robust in the broad range of magnetic fields and gate voltages. Dynamic Hall conductivity of the holelike carriers extracted from the analysis of the transmission data shows a theoretically predicted universal value of σ_{xy}=e^{2}/h, which is consistent with the doubly degenerate Dirac state. On shifting the Fermi level by the gate voltage, the effective sign of the charge carriers changes from positive (holes) to negative (electrons). The electronlike part of the dynamic response does not show quantum plateaus and is well described within the classical Drude model.

  16. Dual role of gravity on the Faraday threshold for immiscible viscous layers.

    PubMed

    Batson, W; Zoueshtiagh, F; Narayanan, R

    2013-12-01

    This work discusses the role of gravity on the Faraday instability, and the differences one can expect to observe in a low-gravity experiment when compared to an earth-based system. These differences are discussed in the context of the viscous linear theory for laterally infinite systems, and a surprising result of the analysis is the existence of a crossover frequency where an interface in low gravity switches from being less to more stable than an earth-based system. We propose this crossover exists in all Faraday systems, and the frequency at which it occurs is shown to be strongly influenced by layer height. In presenting these results physical explanations are provided for the behavior of the predicted forcing amplitude thresholds and wave number selection.

  17. Enhancement of optical Faraday effect of nonanuclear Tb(III) complexes.

    PubMed

    Nakanishi, Takayuki; Suzuki, Yuki; Doi, Yoshihiro; Seki, Tomohiro; Koizumi, Hitoshi; Fushimi, Koji; Fujita, Koji; Hinatsu, Yukio; Ito, Hajime; Tanaka, Katsuhisa; Hasegawa, Yasuchika

    2014-07-21

    The effective magneto-optical properties of novel nonanuclear Tb(III) complexes with Tb-O lattice (specifically, [Tb9(sal-R)16(μ-OH)10](+)NO3(-), where sal-R = alkyl salicylate (R = -CH3 (Me), -C2H5 (Et), -C3H7 (Pr), or -C4H9 (Bu)) are reported. The geometrical structures of these nonanuclear Tb(III) complexes were characterized using X-ray single-crystal analysis and shape-measure calculation. Optical Faraday rotation was observed in nonanuclear Tb(III) complexes in the visible region. The Verdet constant per Tb(III) ion of the Tb9(sal-Me) complex is 150 times larger than that of general Tb(III) oxide glass. To understand their large Faraday rotation, electron paramagnetic resonance measurements of Gd(III) complexes were carried out. In this Report, the magneto-optical relation to the coordination geometry of Tb ions is discussed.

  18. Terahertz spectroscopy on Faraday and Kerr rotations in a quantum anomalous Hall state.

    PubMed

    Okada, Ken N; Takahashi, Youtarou; Mogi, Masataka; Yoshimi, Ryutaro; Tsukazaki, Atsushi; Takahashi, Kei S; Ogawa, Naoki; Kawasaki, Masashi; Tokura, Yoshinori

    2016-07-20

    Electrodynamic responses from three-dimensional topological insulators are characterized by the universal magnetoelectric term constituent of the Lagrangian formalism. The quantized magnetoelectric coupling, which is generally referred to as topological magnetoelectric effect, has been predicted to induce exotic phenomena including the universal low-energy magneto-optical effects. Here we report the experimental indication of the topological magnetoelectric effect, which is exemplified by magneto-optical Faraday and Kerr rotations in the quantum anomalous Hall states of magnetic topological insulator surfaces by terahertz magneto-optics. The universal relation composed of the observed Faraday and Kerr rotation angles but not of any material parameters (for example, dielectric constant and magnetic susceptibility) well exhibits the trajectory towards the fine structure constant in the quantized limit.

  19. Faraday-effect polarimeter-interferometer system for current density measurement on EAST.

    PubMed

    Liu, H Q; Jie, Y X; Ding, W X; Brower, D L; Zou, Z Y; Li, W M; Wang, Z X; Qian, J P; Yang, Y; Zeng, L; Lan, T; Wei, X C; Li, G S; Hu, L Q; Wan, B N

    2014-11-01

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 10(16) m(-2) (∼2°), and the Faraday rotation angle rms phase noise is <0.1°.

  20. Transfer matrix approach for the Kerr and Faraday rotation in layered nanostructures.

    PubMed

    Széchenyi, Gábor; Vigh, Máté; Kormányos, Andor; Cserti, József

    2016-09-21

    To study the optical rotation of the polarization of light incident on multilayer systems consisting of atomically thin conductors and dielectric multilayers we present a general method based on transfer matrices. The transfer matrix of the atomically thin conducting layer is obtained using the Maxwell equations. We derive expressions for the Kerr (Faraday) rotation angle and for the ellipticity of the reflected (transmitted) light as a function of the incident angle and polarization of the light. The method is demonstrated by calculating the Kerr (Faraday) angle for bilayer graphene in the quantum anomalous Hall state placed on the top of dielectric multilayers. The optical conductivity of the bilayer graphene is calculated in the framework of a four-band model.