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Sample records for saturable core magnetometers

  1. Saturation current spikes eliminated in saturable core transformers

    Science.gov (United States)

    Schwarz, F. C.

    1971-01-01

    Unsaturating composite magnetic core transformer, consisting of two separate parallel cores designed so impending core saturation causes signal generation, terminates high current spike in converter primary circuit. Simplified waveform, demonstrates transformer effectiveness in eliminating current spikes.

  2. Double storey three phase saturated cores fault current limiter

    Science.gov (United States)

    Wolfus, Y.; Nikulshin, Y.; Friedman, A.; Yeshurun, Y.

    2014-05-01

    A novel saturated-cores Fault-Current-Limiter (FCL) configuration is described. This FCL is based on two parallel planes of iron rectangular cores, on which three-phase coils are mounted and connected in series to the grid. Two DC coils are mounted in between the planes on perpendicular core limbs connecting the two AC planes. The DC coils are set to magnetically saturate the AC cores. The transition to three-dimensional, double-storey design enables handling three-phase symmetrical faults while offering better decoupling between the AC and DC circuits. At the same time, it shortens the AC limb lengths and enables deeper magnetic saturation levels in comparison to other saturated cores FCL designs. Hence, this FCL configuration exhibits lower insertion impedance and higher ratio of fault to nominal state impedance in comparison with other designs.

  3. Coupled-core fluxgate magnetometer: Novel configuration scheme and the effects of a noise-contaminated external signal

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, Antonio [San Diego State University, Nonlinear Dynamical Systems Group, Department of Mathematics and Statistics, San Diego, CA 92182-7720 (United States)]. E-mail: palacios@euler.sdsu.edu; Aven, John [San Diego State University, Nonlinear Dynamical Systems Group, Department of Mathematics and Statistics, San Diego, CA 92182-7720 (United States); In, Visarath [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull St, San Diego, CA 92152-5001 (United States)]. E-mail: visarath@spawar.navy.mil; Longhini, Patrick [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull St, San Diego, CA 92152-5001 (United States); Kho, Andy [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull St, San Diego, CA 92152-5001 (United States); Neff, Joseph D. [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull St, San Diego, CA 92152-5001 (United States); Bulsara, Adi [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull St, San Diego, CA 92152-5001 (United States)]. E-mail: bulsara@spawar.navy.mil

    2007-07-16

    Recent theoretical and experimental work has shown that unidirectional coupling can induce oscillations in overdamped and undriven nonlinear dynamical systems that are non-oscillatory when uncoupled; in turn, this has been shown to lead to new mechanisms for weak (compared to the energy barrier height) signal detection and amplification. The potential applications include fluxgate magnetometers, electric field sensors, and arrays of Superconducting Quantum Interference Device (SQUID) rings. In the particular case of the fluxgate magnetometer, we have developed a ''coupled-core fluxgate magnetometer'' (CCFM); this device has been realized in the laboratory and its dynamics used to quantify many properties that are generic to this class of systems and coupling. The CCFM operation is underpinned by the emergent oscillatory behavior in a unidirectionally coupled ring of wound ferromagnetic cores, each of which can be treated as an overdamped bistable dynamic system when uncoupled. In particular, one can determine the regimes of existence and stability of the (coupling-induced) oscillations, and the scaling behavior of the oscillation frequency. More recently, we studied the effects of a (Gaussian) magnetic noise floor on a CCFM system realized with N=3 coupled ferromagnetic cores. In this Letter, we first introduce a variation on the basic CCFM configuration that affords a path to enhanced device sensitivity, particularly for N>=3 coupled elements. We then analyze the response of the basic CCFM configuration as well as the new setup to a dc target signal that has a small noisy component (or ''contamination'')

  4. BEHAVIOR OF AN IMMERSED CORE SAMPLE IN A FLUID CONTAINER DURING A SATURATION TECHNIQUE

    Directory of Open Access Journals (Sweden)

    S GHEBOULI

    2002-06-01

    Full Text Available The objective of this paper is to present the behavior of some core samples immersed in a  fluid container during a saturation technique. The experimental work was carried out by using two different fluids. The results obtained are similar except for the saturation stages. They are caused by different viscosities and surface tensions.

  5. Ohmic energy confinement saturation and core toroidal rotation reversal in Alcator C-Mod plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rice, J. E.; Greenwald, M. J.; Podpaly, Y. A.; Reinke, M. L.; Hughes, J. W.; Howard, N. T.; Ma, Y.; Cziegler, I.; Ennever, P. C.; Ernst, D.; Fiore, C. L.; Gao, C.; Irby, J. H.; Marmar, E. S.; Porkolab, M.; Tsujii, N.; Wolfe, S. M. [Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139 (United States); Diamond, P. H. [UCSD, La Jolla, California 92903 (United States); Duval, B. P. [CRPP, EPFL, Lausanne 1015 (Switzerland)

    2012-05-15

    Ohmic energy confinement saturation is found to be closely related to core toroidal rotation reversals in Alcator C-Mod tokamak plasmas. Rotation reversals occur at a critical density, depending on the plasma current and toroidal magnetic field, which coincides with the density separating the linear Ohmic confinement regime from the saturated Ohmic confinement regime. The rotation is directed co-current at low density and abruptly changes direction to counter-current when the energy confinement saturates as the density is increased. Since there is a bifurcation in the direction of the rotation at this critical density, toroidal rotation reversal is a very sensitive indicator in the determination of the regime change. The reversal and confinement saturation results can be unified, since these processes occur in a particular range of the collisionality.

  6. Characterization of trapped gas saturation and heterogeneity in core samples using miscible-displacement experiments

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.H. [USDOE Morgantown Energy Technology Center, WV (United States); Jikich, S.A. [EG& G Technical Services of West Virginia, Inc. (United States)

    1994-12-31

    Trapped gas saturation and permeability heterogeneity were evaluated in Berea cores at reservoir conditions, using standard miscible displacement experiments, with and without surfactants. Pressure and production history were influenced by core heterogeneity and foam lamellae formation when aqueous surfactant was present in the core. A simple dispersion model and a three-coefficient dispersion-capacitance model (Coates-Smith) were fit to the experimental data. The dispersion-capacitance model successfully matched the experiments in which foam lamella formed, while the simple dispersion model was used only for determining initial core flow heterogeneity. The objective of the dispersion-capacitance model was to estimate trapped gas saturations; however longitudinal dispersion and mass transfer also were examined. The results show that the dispersion-capacitance model accurately fits trapped gas saturation controlled by rock heterogeneities and foam lamellae for lamella generating mechanisms that allow a continuous gas phase (leave-behind lamellae). The practical applications resulting from this study can aid in core sample selection and scaling short laboratory corefloods to field dimensions for applications to foam stimulation and underground storage of natural gas.

  7. The effect of winding and core support material on the thermal gain dependence of a fluxgate magnetometer sensor

    Directory of Open Access Journals (Sweden)

    D. M. Miles

    2017-10-01

    Full Text Available Fluxgate magnetometers are an important tool in geophysics and space physics but are typically sensitive to variations in sensor temperature. Changes in instrumental gain with temperature, thermal gain dependence, are thought to be predominantly due to changes in the geometry of the wire coils that sense the magnetic field and/or provide magnetic feedback. Scientific fluxgate magnetometers typically employ some form of temperature compensation and support and constrain wire sense coils with bobbins constructed from materials such as MACOR machinable ceramic (Corning Inc. which are selected for their ultra-low thermal deformation rather than for robustness, cost, or ease of manufacturing. We present laboratory results comparing the performance of six geometrically and electrically matched fluxgate sensors in which the material used to support the windings and for the base of the sensor is varied. We use a novel, low-cost thermal calibration procedure based on a controlled sinusoidal magnetic source and quantitative spectral analysis to measure the thermal gain dependence of fluxgate magnetometer sensors at the ppm°C−1 level in a typical magnetically noisy university laboratory environment. We compare the thermal gain dependence of sensors built from MACOR, polyetheretherketone (PEEK engineering plastic (virgin, 30 % glass filled and 30 % carbon filled, and acetal to examine the trade between the thermal properties of the material, the impact on the thermal gain dependence of the fluxgate, and the cost and ease of manufacture. We find that thermal gain dependence of the sensor varies as one half of the material properties of the bobbin supporting the wire sense coils rather than being directly related as has been historically thought. An experimental sensor constructed from 30 % glass-filled PEEK (21.6 ppm°C−1 had a thermal gain dependence within 5 ppm°C−1 of a traditional sensor constructed from MACOR ceramic (8.1

  8. The effect of winding and core support material on the thermal gain dependence of a fluxgate magnetometer sensor

    Science.gov (United States)

    Miles, David M.; Mann, Ian R.; Kale, Andy; Milling, David K.; Narod, Barry B.; Bennest, John R.; Barona, David; Unsworth, Martyn J.

    2017-10-01

    Fluxgate magnetometers are an important tool in geophysics and space physics but are typically sensitive to variations in sensor temperature. Changes in instrumental gain with temperature, thermal gain dependence, are thought to be predominantly due to changes in the geometry of the wire coils that sense the magnetic field and/or provide magnetic feedback. Scientific fluxgate magnetometers typically employ some form of temperature compensation and support and constrain wire sense coils with bobbins constructed from materials such as MACOR machinable ceramic (Corning Inc.) which are selected for their ultra-low thermal deformation rather than for robustness, cost, or ease of manufacturing. We present laboratory results comparing the performance of six geometrically and electrically matched fluxgate sensors in which the material used to support the windings and for the base of the sensor is varied. We use a novel, low-cost thermal calibration procedure based on a controlled sinusoidal magnetic source and quantitative spectral analysis to measure the thermal gain dependence of fluxgate magnetometer sensors at the ppm°C-1 level in a typical magnetically noisy university laboratory environment. We compare the thermal gain dependence of sensors built from MACOR, polyetheretherketone (PEEK) engineering plastic (virgin, 30 % glass filled and 30 % carbon filled), and acetal to examine the trade between the thermal properties of the material, the impact on the thermal gain dependence of the fluxgate, and the cost and ease of manufacture. We find that thermal gain dependence of the sensor varies as one half of the material properties of the bobbin supporting the wire sense coils rather than being directly related as has been historically thought. An experimental sensor constructed from 30 % glass-filled PEEK (21.6 ppm°C-1) had a thermal gain dependence within 5 ppm°C-1 of a traditional sensor constructed from MACOR ceramic (8.1 ppm°C-1). If a modest increase in thermal

  9. Real-time oil-saturation monitoring in rock cores with low-field NMR

    Science.gov (United States)

    Mitchell, J.; Howe, A. M.; Clarke, A.

    2015-07-01

    Nuclear magnetic resonance (NMR) provides a powerful suite of tools for studying oil in reservoir core plugs at the laboratory scale. Low-field magnets are preferred for well-log calibration and to minimize magnetic-susceptibility-induced internal gradients in the porous medium. We demonstrate that careful data processing, combined with prior knowledge of the sample properties, enables real-time acquisition and interpretation of saturation state (relative amount of oil and water in the pores of a rock). Robust discrimination of oil and brine is achieved with diffusion weighting. We use this real-time analysis to monitor the forced displacement of oil from porous materials (sintered glass beads and sandstones) and to generate capillary desaturation curves. The real-time output enables in situ modification of the flood protocol and accurate control of the saturation state prior to the acquisition of standard NMR core analysis data, such as diffusion-relaxation correlations. Although applications to oil recovery and core analysis are demonstrated, the implementation highlights the general practicality of low-field NMR as an inline sensor for real-time industrial process control.

  10. Sulfur Saturation Limits in Silicate Melts and their Implications for Core Formation Scenarios for Terrestrial Planets

    Science.gov (United States)

    Holzheid, Astrid; Grove, Timothy L.

    2002-01-01

    This study explores the controls of temperature, pressure, and silicate melt composition on S solubility in silicate liquids. The solubility of S in FeO-containing silicate melts in equilibrium with metal sulfide increases significantly with increasing temperature but decreases with increasing pressure. The silicate melt structure also exercises a control on S solubility. Increasing the degree of polymerization of the silicate melt structure lowers the S solubility in the silicate liquid. The new set of experimental data is used to expand the model of Mavrogenes and O'Neill(1999) for S solubility in silicate liquids by incorporating the influence of the silicate melt structure. The expected S solubility in the ascending magma is calculated using the expanded model. Because the negative pressure dependence of S solubility is more influential than the positive temperature dependence, decompression and adiabatic ascent of a formerly S-saturated silicate magma will lead to S undersaturation. A primitive magma that is S-saturated in its source region will, therefore, become S-undersaturated as it ascends to shallower depth. In order to precipitate magmatic sulfides, the magma must first cool and undergo fractional crystallization to reach S saturation. The S content in a metallic liquid that is in equilibrium with a magma ocean that contains approx. 200 ppm S (i.e., Earth's bulk mantle S content) ranges from 5.5 to 12 wt% S. This range of S values encompasses the amount of S (9 to 12 wt%) that would be present in the outer core if S is the light element. Thus, the Earth's proto-mantle could be in equilibrium (in terms of the preserved S abundance) with a core-forming metallic phase.

  11. Suggested Methods for Preventing Core Saturation Instability in HVDC Transmission Systems

    Energy Technology Data Exchange (ETDEWEB)

    Norheim, Ian

    2002-07-01

    In this thesis a study of the HVDC related phenomenon core saturation instability and methods to prevent this phenomenon is performed. It is reason to believe that this phenomenon caused disconnection of the Skagerrak HVDC link 10 August 1993. Internationally, core saturation instability has been reported at several HVDC schemes and thorough complex studies of the phenomenon has been performed. This thesis gives a detailed description of the phenomenon and suggest some interesting methods to prevent the development of it. Core saturation instability and its consequences can be described in a simplified way as follows: It is now assumed that a fundamental harmonic component is present in the DC side current. Due to the coupling between the AC side and the DC side of the HVDC converter, a subsequent second harmonic positive-sequence current and DC currents will be generated on the AC side. The DC currents will cause saturation in the converter transformers. This will cause the magnetizing current to also have a second harmonic positive-sequence component. If a high second harmonic impedance is seen from the commutation bus, a high positive-sequence second harmonic component will be present in the commutation voltages. This will result in a relatively high fundamental frequency component in the DC side voltage. If the fundamental frequency impedance at the DC side is relatively low the fundamental component in the DC side current may become larger than it originally was. In addition the HVDC control system may contribute to the fundamental frequency component in the DC side voltage, and in this way cause a system even more sensitive to core saturation instability. The large magnetizing currents that eventually will flow on the AC side cause large zero-sequence currents in the neutral conductors of the AC transmission lines connected to the HVDC link. This may result in disconnection of the lines. Alternatively, the harmonics in the large magnetizing currents may cause

  12. A portable Hall magnetometer probe for characterization of magnetic iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Jefferson F.D.F.; Costa, Mateus C.; Louro, Sonia R.W.; Bruno, Antonio C., E-mail: acbruno@puc-rio.br

    2017-03-15

    We have built a portable Hall magnetometer probe, for measuring magnetic properties of iron oxide nanoparticles, that can be used for bulk materials and liquid samples as well. The magnetometer probe consists of four voltage-programmable commercial Hall sensors and a thin acrylic plate for positioning the sensors. In order to operate, it needs to be attached to a pole of an electromagnet and connected to an AD converter and a computer. It acquires a complete magnetization curve in a couple of minutes and has a magnetic moment sensitivity of 3.5×10{sup −7} Am{sup 2}. We tested its performance with magnetic nanoparticles containing an iron oxide core and having coating layers with different sizes. The magnetization results obtained were compared with measurements performed on commercial stand-alone magnetometers, and exhibited errors of about ±0.2 Am{sup 2}/kg (i.e 0.4%) at saturation and below 0.5 Am{sup 2}/kg (i.e. 10%) at remanence. - Highlights: • A low-cost portable Hall magnetometer probe has been built. • The Hall magnetometer probe can be attached to any electromagnet. • The Hall probe was calibrated and successfully compared to industry standard magnetometers. • The Hall probe was able to measure iron oxide nanoparticles with different coatings.

  13. Displacement front behavior of near miscible CO2flooding in decane saturated synthetic sandstone cores revealed by magnetic resonance imaging.

    Science.gov (United States)

    Liu, Yu; Teng, Ying; Jiang, Lanlan; Zhao, Jiafei; Zhang, Yi; Wang, Dayong; Song, Yongchen

    2017-04-01

    It is of great importance to study the CO 2 -oil two-phase flow characteristic and displacement front behavior in porous media, for understanding the mechanisms of CO 2 enhanced oil recovery. In this work, we carried out near miscible CO 2 flooding experiments in decane saturated synthetic sandstone cores to investigate the displacement front characteristic by using magnetic resonance imaging technique. Experiments were done in three consolidated sandstone cores with the permeabilities ranging from 80 to 450mD. The oil saturation maps and the overall oil saturation during CO 2 injections were obtained from the intensity of magnetic resonance imaging. Finally the parameters of the piston-like displacement fronts, including the front velocity and the front geometry factor (the length to width ratio) were analyzed. Experimental results showed that the near miscible vertical upward displacement is instable above the minimum miscible pressure in the synthetic sandstone cores. However, low permeability can restrain the instability to some extent. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Aristoteles magnetometer system

    Science.gov (United States)

    Smith, Edward J.; Marquedant, Roy J.; Langel, Robert; Acuna, Mario

    1991-12-01

    A magnetometer system capable of meeting the stringent requirements of the Aristoteles mission is described. The system will comprise a three axis or Vector Flux gas Magnetometer (VFM) and a highly accurate resonance magnetometer, the Scalar Helium Magnetometer (SHM). Basic operational features of these instruments are described and their performance is related to the scientific objectives of the mission appropriate to the geomagnetic field measurements. The major requirements imposed on the spacecraft are summarized. Photographs and diagrams of both instruments are presented along with graphs of the sensitivity of the SHM to magnetic field orientation.

  15. Modeling of viscoelastic properties of nonpermeable porous rocks saturated with highly viscous fluid at seismic frequencies at the core scale

    Science.gov (United States)

    Wang, Zizhen; Schmitt, Douglas R.; Wang, Ruihe

    2017-08-01

    A core scale modeling method for viscoelastic properties of rocks saturated with viscous fluid at low frequencies is developed based on the stress-strain method. The elastic moduli dispersion of viscous fluid is described by the Maxwell's spring-dash pot model. Based on this modeling method, we numerically test the effects of frequency, fluid viscosity, porosity, pore size, and pore aspect ratio on the storage moduli and the stress-strain phase lag of saturated rocks. And we also compared the modeling results to the Hashin-Shtrikman bounds and the coherent potential approximation (CPA). The dynamic moduli calculated from the modeling are lower than the predictions of CPA, and both of these fall between the Hashin-Shtrikman bounds. The modeling results indicate that the frequency and the fluid viscosity have similar effects on the dynamic moduli dispersion of fully saturated rocks. We observed the Debye peak in the phase lag variation with the change of frequency and viscosity. The pore structure parameters, such as porosity, pore size, and aspect ratio affect the rock frame stiffness and result in different viscoelastic behaviors of the saturated rocks. The stress-strain phase lags are larger with smaller stiffness contrasts between the rock frame and the pore fluid. The viscoelastic properties of saturated rocks are more sensitive to aspect ratio compared to other pore structure parameters. The results suggest that significant seismic dispersion (at about 50-200 Hz) might be expected for both compressional and shear waves passing through rocks saturated with highly viscous fluids.type="synopsis">type="main">Plain Language SummaryWe develop a core scale modeling method to simulate the viscoelastic properties of rocks saturated with viscous fluid at low frequencies based on the stress-strain method. The elastic moduli dispersion of viscous fluid is described by the Maxwell's spring-dash pot model. By using this modeling method, we numerically test the effects of

  16. Dynamic analysis of atomic magnetometer and co-magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shihu, E-mail: 65980623@qq.com; Yu, Linke; Wang, Wei

    2016-03-01

    Some unsteady-state solutions of Bloch equation which well-describe the behavior of a magnetometer are obtained. These solutions are in accord with the experimental result of alkali-metal magnetometer and co-magnetometer gyroscope. Many interesting phenomena can be also achieved via the solutions. First, the measuring direction of a magnetometer changes with the variation of external magnetic field along z axis. And it could be used for measuring high frequency magnetic field. Then it can be extended that the co-magnetometer without compensated field can get better performance than simple atomic magnetometer due to the effect of polarized noble gas. Finally, we discussed the limits (bandwidth and so on) of atomic magnetometer and co-magnetometer with the Bloch equation of spins. These phenomena, which have not been mentioned before, may contribute to the development of atomic magnetometer and co-magnetometer gyroscope.

  17. Spaced-based search coil magnetometers

    Science.gov (United States)

    Hospodarsky, George B.

    2016-12-01

    Search coil magnetometers are one of the primary tools used to study the magnetic component of low-frequency electromagnetic waves in space. Their relatively small size, mass, and power consumption, coupled with a good frequency range and sensitivity, make them ideal for spaceflight applications. The basic design of a search coil magnetometer consists of many thousands of turns of wire wound on a high permeability core. When a time-varying magnetic field passes through the coil, a time-varying voltage is induced due to Faraday's law of magnetic induction. The output of the coil is usually attached to a preamplifier, which amplifies the induced voltage and conditions the signal for transmission to the main electronics (usually a low-frequency radio receiver). Search coil magnetometers are usually used in conjunction with electric field antenna to measure electromagnetic plasma waves in the frequency range of a few hertz to a few tens of kilohertzs. Search coil magnetometers are used to determine the properties of waves, such as comparing the relative electric and magnetic field amplitudes of the waves, or to investigate wave propagation parameters, such as Poynting flux and wave normal vectors. On a spinning spacecraft, they are also sometimes used to determine the background magnetic field. This paper presents some of the basic design criteria of search coil magnetometers and discusses design characteristics of sensors flown on a number of spacecraft.

  18. GOES Space Environment Monitor, Magnetometer

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Three orthogonal flux-gate magnetometer elements, (spinning twin fluxgate magnetometer prior to GOES-8) provide magnetic field measurements in three mutually...

  19. Non-resonant wavelength modulation saturation spectroscopy in acetylene-filled hollow-core photonic bandgap fibres applied to modulation-free laser diode stabilisation.

    Science.gov (United States)

    Pineda-Vadillo, Pablo; Lynch, Michael; Charlton, Christy; Donegan, John F; Weldon, Vincent

    2009-12-07

    In this paper the application of Wavelength Modulation (WM) techniques to non-resonant saturation spectroscopy in acetylene-filled Hollow-Core Photonic Bandgap Fibres (HC-PBFs) and modulation-free Laser Diode (LD) frequency stabilisation is investigated. In the first part WM techniques are applied to non-resonant pump-probe saturation of acetylene overtone rotational transitions in a HC-PBF. A high-power DFB chip-on-carrier mounted LD is used in conjunction with a tuneable External Cavity Laser (ECL) and the main saturation parameters are characterized. In the second part a novel feedback system to stabilize the DFB emission wavelength based on the WM saturation results is implemented. Modulation-free locking of the DFB laser frequency to the narrow linewidth saturation feature is achieved for both constant and variable LD temperatures.

  20. THOR Fluxgate Magnetometer (MAG)

    Science.gov (United States)

    Nakamura, Rumi; Eastwood, Jonathan; Magnes, Werner; Carr, Christopher, M.; O'Brien, Helen, L.; Narita, Yasuhito; K, Chen, Christopher H.; Berghofer, Gerhard; Valavanoglou, Aris; Delva, Magda; Plaschke, Ferdinand; Cupido, Emanuele; Soucek, Jan

    2017-04-01

    Turbulence Heating ObserveR (THOR) is the first mission ever flown in space dedicated to plasma turbulence. The fluxgate Magnetometer (MAG) measures the background to low frequency magnetic field. The high sensitivity measurements of MAG enable to characterize the nature of turbulent fluctuations as well as the large-scale context. MAG will provide the reference system for determining anisotropy of field fluctuations, pitch-angle and gyro-phase of particles. The design of the magnetometer consists of two tri-axial sensors and the related magnetometer electronics; the electronics are hosted on printed circuit boards in the common electronics box of the fields and wave processor (FWP). A fully redundant two- sensor system mounted on a common boom and the new miniaturized low noise design based on MMS and Solar Orbiter instruments enable accurate measurement throughout the region of interest for THOR science. The usage of the common electronics hosted by FWP guarantees to fulfill the required timing accuracy with other fields measurements. These improvements are important to obtain precise measurements of magnetic field, which is essential to estimate basic plasma parameters and correctly identify the spatial and temporal scales of the turbulence. Furthermore, THOR MAG provides high quality data with sufficient overlap with the Search Coil Magnetometer (SCM) in frequency space to obtain full coverage of the wave forms over all the frequencies necessary to obtain the full solar wind turbulence spectrum from MHD to kinetic range with sufficient accuracy. We discuss the role of MAG in THOR key science questions and present the new developments during Phase A such as the finalised instrument design, MAG relevant requirement, and new calibraion schemes.

  1. Design of a Low-Cost 2-Axes Fluxgate Magnetometer for Small Satellite Applications

    Directory of Open Access Journals (Sweden)

    Su-Jeoung Kim

    2005-03-01

    Full Text Available This paper addresses the design and analysis results of a 2-axes magnetometer for attitude determination of small satellite. A low-cost and efficient 2-axes fluxgate magnetometer was selected as the most suitable attitude sensor for LEO microsatellites which require a low-to-medium level pointing accuracy. An optimization trade-off study has been performed for the development of 2-axes fluxgate magnetometer. All the relevant parameters such as permeability, demagnetization factor, coil diameter, core thickness, and number of coil turns were considered for the sizing of a small satellite magnetometer. The magnetometer which is designed, manufactured, and tested in-house as described in this paper satisfies linearity requirement for determining attitude position of small satellites. On the basis of magnetometer which is designed in Space System Research Lab. (SSRL, commercial magnetometer will be developed.

  2. THREE-PHASE TRANSFORMER PARAMETERS CALCULATION CONSIDERING THE CORE SATURATION FOR THE MATLAB-SIMULINK TRANSFORMER MODEL

    Directory of Open Access Journals (Sweden)

    I. V. Novash

    2015-01-01

    Full Text Available This article describes the parameters calculation for the three-phase two-winding power transformer model taken from the SimPowerSystems library, which is the part of the MatLab- Simulink environment. Presented methodology is based on the power transformer nameplate data usage. Particular attention is paid to the power transformer magnetization curve para- meters  calculation.  The  methodology  of  the  three-phase  two-winding  power  transformer model parameters calculation considering the magnetization curve nonlinearity isn’t presented in Russian-and English-language sources. Power transformers demo models described in the SimPowerSystems user’s guide have already calculated parameters, but without reference to the sources of their determination. A power transformer is a nonlinear element of the power system, that’s why for its performance analysis in different modes of operation is necessary to have the magnetization curve parameters.The process analysis during no-load energizing of the power transformer is of special interest. This regime is accompanied by the inrush current on the supply side of the power transformer, which is several times larger than the transformer rated current. Sharp rising of the magnetizing current is explained by the magnetic core saturation. Therefore, magnetiza- tion characteristic accounting during transformer no-load energizing modeling is a mandatory requirement. Article authors attempt to put all calculating formulas in a more convenient form and validate the power transformer nonlinear magnetization characteristics parameters calcu- lation. Inrush current oscillograms obtained during the simulation experiment confirmed the adequacy of the calculated model parameters.

  3. Control of Saturation level in the magnetic core of a welding transformer by Hysteresis Controller (HC and Proportional Integral (PI Controller

    Directory of Open Access Journals (Sweden)

    Rama Subbanna.S

    2016-12-01

    Full Text Available The objective of this paper is to analyse the performances of two controllers such as Hysteresis control (HC and proportional integral (PI control to control saturation level in the magnetic core of a welding transformer in a middle-frequency direct current (MFDC resistance spot welding system(RSWS. It consists of an input converter, welding transformer, and a full-wave rectifier mounted at the transformer secondary. The unequal ohmic resistances of the two transformer’s secondary circuits and the different characteristics of the diodes of output rectifier certainly lead to the magnetic core saturation which, consequently, causes the unwanted spikes in the transformer’s primary current and over-current protection switch-off. The goal is to analyse the performance of both controllers in terms of transients, total harmonic distortion(THD and variations in primary current and flux in the magnetic core of a welding transformer of highly nonlinear system of RSWS. The simulation study has been done in Matlab/Simulink environment and presented performance analysis. The responses shows that from the aforementioned aspects, proportional integral Controller is the better choice for controlling the saturation level in magnetic core of a welding transformer which is widely used in automobile industry welding system.

  4. Scalar magnetometers for space applications

    DEFF Research Database (Denmark)

    Primdahl, Fritz

    magnetometer, offer stability and resolution well suited for the calibration purposes. Recent developments are discussed. The metastable Helium magnetometer also offers quasi-absolute scalar measurements, and the use of semiconductor tuned lasers replacing an RF-excited Helium lamp holds great promise...

  5. Invasion Percolation on Correlated and Elongated Lattices : Implications for the Interpretation of Residual Saturations in Rock Cores

    NARCIS (Netherlands)

    Knackstedt, Mark A.; Marrink, S.J.; Sheppard, Adrian P.; Pinczewski, W.V.; Sahimi, Muhammad

    2001-01-01

    The invasion percolation model is used to investigate the effect of correlated heterogeneity on capillary dominated displacements in porous media. The breakthrough and residual saturations are shown to be strongly influenced by the correlations. Correlated heterogeneity leads to lower residual

  6. Optically transduced MEMS magnetometer

    Science.gov (United States)

    Nielson, Gregory N; Langlois, Eric

    2014-03-18

    MEMS magnetometers with optically transduced resonator displacement are described herein. Improved sensitivity, crosstalk reduction, and extended dynamic range may be achieved with devices including a deflectable resonator suspended from the support, a first grating extending from the support and disposed over the resonator, a pair of drive electrodes to drive an alternating current through the resonator, and a second grating in the resonator overlapping the first grating to form a multi-layer grating having apertures that vary dimensionally in response to deflection occurring as the resonator mechanically resonates in a plane parallel to the first grating in the presence of a magnetic field as a function of the Lorentz force resulting from the alternating current. A plurality of such multi-layer gratings may be disposed across a length of the resonator to provide greater dynamic range and/or accommodate fabrication tolerances.

  7. Scalar Calibration of Vector Magnetometers

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Brauer, Peter; Primdahl, Fritz

    2000-01-01

    The calibration parameters of a vector magnetometer are estimated only by the use of a scalar reference magnetometer. The method presented in this paper differs from those previously reported in its linearized parametrization. This allows the determination of three offsets or signals in the absence...... of a magnetic field, three scale factors for normalization of the axes and three non-orthogonality angles which build up an orthogonal system intrinsically in the sensor. The advantage of this method compared with others lies in its linear least squares estimator, which finds independently and uniquely...... the parameters for a given data set. Therefore, a magnetometer may be characterized inexpensively in the Earth's magnetic-field environment. This procedure has been used successfully in the pre-flight calibration of the state-of-the-art magnetometers on board the magnetic mapping satellites Orsted, Astrid-2...

  8. All optical vector magnetometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I research project will investigate a novel method of operating an atomic magnetometer to simultaneously measure total magnetic fields and vector magnetic...

  9. GALILEO MAGNETOMETER CRUISE EDR DATA

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains data acquired by the Galileo Magnetometer during the Interplanetary Cruise to Jupiter. The data are at varying resolution depending on the...

  10. Miniature Laser Magnetometer (MLM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This 2009 NASA SBIR Phase 2 proposal for an innovative Miniature Laser Magnetometer (MLM) is a response to subtopic S1.06 Particles and Field Sensors and Instrument...

  11. Miniature Laser Magnetometer (MLM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This 2009 NASA SBIR Phase 1 proposal for an innovative Miniature Laser Magnetometer (MLM) is a response to subtopic S1.06 Particles and Field Sensors and Instrument...

  12. Magnetogama: an open schematic magnetometer

    Science.gov (United States)

    Wahyudi; Khakhim, Nurul; Kuntoro, Tri; Mardiatno, Djati; Rakhman, Afif; Setyo Handaru, Anas; Akhmad Mufaqih, Adien; Marwan Irnaka, Theodosius

    2017-09-01

    Magnetogama is an open schematic hand-assembled fluxgate magnetometer. Compared to another magnetometer, Magnetogama has more benefit concerning its price and its ease of use. Practically Magnetogama can be utilized either in land or attached to an unmanned aerial vehicle (UAV). Magnetogama was designed to give open access to a cheap and accurate alternative to magnetometer sensor. Therefore it can be used as a standard design which is directly applicable to the low-budget company or education purposes. Schematic, code and several verification tests were presented in this article ensuring its reproducibility. Magnetogama has been tested with two kind of tests: a comparison with two nearest observatories at Learmonth (LRM) and Kakadu (KDU) and the response of magnetic substance.

  13. Methane hydrate pore saturation evaluation from geophysical logging and pressure core analysis, at the first offshore production test site in the eastern Nankai Trough, Japan

    Science.gov (United States)

    Fujii, T.; Suzuki, K.; Takayama, T.; Konno, Y.; Yoneda, J.; Egawa, K.; Ito, T.; Nagao, J.

    2013-12-01

    On March 2013, the first offshore production test form methane hydrate (MH) concentrated zone (MHCZ) was conducted by the Research Consortium for Methane Hydrate Resource Development in Japan (MH21) at the AT1 site located in the north-western slope of Daini-Atsumi Knoll in the eastern Nankai Trough, Japan. Before the production test, extensive geophysical logging and pressure coring using Hybrid Pressure Coring System were conducted in 2012 at monitoring well (AT1-MC) and coring well (AT1-C), in order to obtain basic information for the MH reservoir characterization. MH pore saturation (Sh) is one of the important basic parameters not only for reservoir characterization, but also the resource assessment. However, precise evaluation of Sh from geophysical logging is still challenging technical issue. The MHCZ confirmed by the geophysical logging at AT1-MC has a turbidite assemblage (from several tens of centimeters to a few meters) with 60 m of gross thickness; it is composed of lobe/sheet type sequences in the upper part, and relatively thick channel sand sequences in the lower part. In this study, the Sh evaluated from geophysical logging data were compared with those evaluated from pressure core analysis. Resistivity logs and nuclear magnetic resonance (NMR) log were used for the Sh evaluation by geophysical logging. Standard Archie equation was applied for Sh evaluation from resistivity log, while density magnetic resonance (DMR) method was used for Sh evaluation from NMR log. The Sh from pressure core samples were evaluated using the amount of dissociated gas volume, together with core sample bulk volume, measured porosity, net sand intervals, and assumed methane solubility in pore water. In the upper part of the MHCZ, Sh estimated from resistivity log showed distinct difference in value between sand and mud layers, compared to Sh from NMR log. Resistivity log has higher vertical resolution than NMR log, so it is favorable for these kinds of thin bed

  14. An Arduino-Based Magnetometer

    Science.gov (United States)

    McCaughey, Mike

    2017-01-01

    An Arduino-based system with a triple axis magnetometer chip may be used to plot both the strength and direction of the magnetic field of a magnet directly on a sheet of paper. Before taking measurements, it is necessary either to correct for or to eliminate soft and hard iron effects. The same sensor may be used to determine the presence of soft…

  15. All-optical, Three-axis Fiber Laser Magnetometer

    Science.gov (United States)

    2012-04-16

    force acting on a current carrying bridge in the presence of a magnetic field, which drives its oscillation measured with a fiber laser strain sensor... strain between two cores as a function of rotation for difference inclinations and (b) reported inclination vs. actual inclination for a bend angle of...such as those based on SQUIDS, giant magnetoresistance (GMR), scalar resonance magnetometers, and flux-gates; however, a fiber optic sensor enables

  16. Induction Magnetometers – Design Peculiarities

    Directory of Open Access Journals (Sweden)

    Valeriy KOREPANOV

    2010-09-01

    Full Text Available Induction or search-coil magnetometers (IM are widely used in many branches of science and industry. The frequency range and dynamic range of IMs are probably the widest of all existing magnetometers: they are used for the measurement of magnetic field variations in the frequency band from ~10-4 till ~106 Hz with the intensities from fractions of femtotesla till tens of tesla. This explains the permanent interest to IM design and the attempts to construct the IMs with best possible parameters. The present paper deals with the peculiarities of IM design. An attempt to re-establish the correctness of priorities in the field is made and the approaches to the IM optimization and their quality estimation are described.

  17. Atomic magnetometer for human magnetoencephalograpy.

    Energy Technology Data Exchange (ETDEWEB)

    Schwindt, Peter; Johnson, Cort N.

    2010-12-01

    We have developed a high sensitivity (<5 fTesla/{radical}Hz), fiber-optically coupled magnetometer to detect magnetic fields produced by the human brain. This is the first demonstration of a noncryogenic sensor that could replace cryogenic superconducting quantum interference device (SQUID) magnetometers in magnetoencephalography (MEG) and is an important advance in realizing cost-effective MEG. Within the sensor, a rubidium vapor is optically pumped with 795 laser light while field-induced optical rotations are measured with 780 nm laser light. Both beams share a single optical axis to maximize simplicity and compactness. In collaboration with neuroscientists at The Mind Research Network in Albuquerque, NM, the evoked responses resulting from median nerve and auditory stimulation were recorded with the atomic magnetometer and a commercial SQUID-based MEG system with signals comparing favorably. Multi-sensor operation has been demonstrated with two AMs placed on opposite sides of the head. Straightforward miniaturization would enable high-density sensor arrays for whole-head magnetoencephalography.

  18. Composite Rolled Magnetometer and Instrument Boom Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Magnetometers are the most common instrument flown on NASA science missions and interference from onboard electronics requires that these instruments be deployed...

  19. CORE

    DEFF Research Database (Denmark)

    Krigslund, Jeppe; Hansen, Jonas; Hundebøll, Martin

    2013-01-01

    different flows. Instead of maintaining these approaches separate, we propose a protocol (CORE) that brings together these coding mechanisms. Our protocol uses random linear network coding (RLNC) for intra- session coding but allows nodes in the network to setup inter- session coding regions where flows...... intersect. Routes for unicast sessions are agnostic to other sessions and setup beforehand, CORE will then discover and exploit intersecting routes. Our approach allows the inter-session regions to leverage RLNC to compensate for losses or failures in the overhearing or transmitting process. Thus, we...... increase the benefits of XORing by exploiting the underlying RLNC structure of individual flows. This goes beyond providing additional reliability to each individual session and beyond exploiting coding opportunistically. Our numerical results show that CORE outperforms both forwarding and COPE...

  20. Nuclear quantum-assisted magnetometer

    Science.gov (United States)

    Häberle, Thomas; Oeckinghaus, Thomas; Schmid-Lorch, Dominik; Pfender, Matthias; de Oliveira, Felipe Fávaro; Momenzadeh, Seyed Ali; Finkler, Amit; Wrachtrup, Jörg

    2017-01-01

    Magnetic sensing and imaging instruments are important tools in biological and material sciences. There is an increasing demand for attaining higher sensitivity and spatial resolution, with implementations using a single qubit offering potential improvements in both directions. In this article we describe a scanning magnetometer based on the nitrogen-vacancy center in diamond as the sensor. By means of a quantum-assisted readout scheme together with advances in photon collection efficiency, our device exhibits an enhancement in signal to noise ratio of close to an order of magnitude compared to the standard fluorescence readout of the nitrogen-vacancy center. This is demonstrated by comparing non-assisted and assisted methods in a T1 relaxation time measurement.

  1. A ocean bottom vector magnetometer

    Science.gov (United States)

    Wang, Xiaomei; Teng, Yuntian; Wang, Chen; Ma, Jiemei

    2017-04-01

    The new development instrument with a compact spherical coil system and Overhauser magnetometer for measuring the total strength of the magnetic field and the vectors of strength, Delta inclination - Delta declination, meanwhile we also use a triaxial fluxgate instrument of the traditional instrument for geomagnetic vector filed measurement. The advantages of this method are be calibrated by each other and get good performances with automatic operation, good stability and high resolution. Firstly, a brief description of the instrument measurement principles and the key technologies are given. The instrument used a spherical coil system with 34 coils to product the homogeneous volume inside the coils which is large enough to accommodate the sensor of Overhauser total field sensor; the rest of the footlocker-sized ocean-bottom vector magnetometer consists of equipment to run the sensors and records its data (batteries and a data logger), weight to sink it to the sea floor, a remote-controlled acoustic release and flotation to bring the instrument back to the surface. Finally, the accuracy of the instrument was tested in the Geomagnetic station, and the measurement accuracies of total strength and components were better than 0.2nT and 1nT respectively. The figure 1 shows the development instrument structure. it includes six thick glass spheres which protect the sensor, data logger and batteries from the pressures of the deep sea, meanwhile they also provide recycling positive buoyancy; To cushion the glass, the spheres then go inside yellow plastic "hardhats". The triaxial fluxgate is inside No.1 glass spheres, data logger and batteries are inside No.2 glass spheres, the new vector sensor is inside No.3 glass spheres, acoustic communication unit is inside No.4 glass spheres, No.5 and No.6 glass spheres are empty which only provide recycling positive buoyancy. The figure 2 shows the development instrument Physical photo.

  2. Fetal MCG with Atomic Magnetometer Array

    Science.gov (United States)

    Deland, Zack; Bulatowicz, Michael D.; Sulai, Ibrahim A.; Wahl, Colin P.; Wakai, Ronald T.; Walker, Thad G.

    2016-05-01

    We present results on the development of 87Rb atomic magnetometers for the detection of a fetal magnetocardiogram (fMCG). Operating in the spin-exchange relaxation free (SERF) regime, the magnetometers' sensitivities are reported at the 1 fT /√{ Hz } level. Environmental common-mode noise, including the field from the maternal heart, can be suppressed by operating the magnetometers in a gradiometric configuration. We report on schemes from implementing such gradiometers along with recent fMCG measurements. This work is supported by the National Institutes of Health.

  3. Magnetometer Data recovered from 35mm film

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The L57 CDMP recovery project takes magnetometer data on 35mm film stored at the archive's climate controlled warehouse and digitizes them.

  4. GALILEO MAGNETOMETER CRUISE DATA (RTN COORDINATES)

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset contains data acquired by the Galileo Magnetometer during the Interplanetary Cruise to Jupiter. The data are at varying resolution depending on the...

  5. Optically-Modulated Miniature Magnetometer (OMMM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Design, fabricate, and calibrate a compact helium magnetometer for high-accuracy measurements of Earth’s magnetic field Provide vector and scalar measurements...

  6. Digital Detection and feedback Fluxgate Magnetometer

    DEFF Research Database (Denmark)

    Piil-Henriksen, J.; Merayo, José M.G.; Nielsen, Otto V

    1996-01-01

    A new full Earth's field dynamic feedback fluxgate magnetometer is described. It is based entirely on digital signal processing and digital feedback control, thereby replacing the classical second harmonic tuned analogue electronics by processor algorithms. Discrete mathematical cross...

  7. ICE MAGNETOMETER DATA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — These data were obtained from the JPL magnetometer experiment on ICE (Principal Investigator: E.J. Smith produces three, high-accuracy, triaxial measurements per...

  8. Cryogenic pulsed inductive microwave magnetometer

    Science.gov (United States)

    Kos, A. B.; Nibarger, J. P.; Lopusnik, R.; Silva, T. J.; Celinski, Z.

    2003-05-01

    A cryogenic pulsed inductive microwave magnetometer is used to characterize the switching dynamics in thin-film magnetic materials at low temperatures and microwave frequencies. The system is contained inside a 20-cm-diam ultrahigh vacuum chamber and cooled by a cryopump that allows measurements between 20 and 350 K. A temperature controller regulates the sample temperature using two silicon diodes as sensors. Applied magnetic fields of up to 36 kA/m (450 Oe) are generated by a four-pole, water-cooled electromagnet with independent control of each axis. Magnetic switching in the sample is driven by high-speed current step pulses in a coplanar waveguide structure with the sample placed in a flip-chip configuration. A 20 GHz sampling oscilloscope is used to record the dynamics of the magnetic reorientation. The switching dynamics are given for a 10-nm-thick Ni-Fe film at 30 K in response to a 1 kA/m field step.

  9. A phaseonium magnetometer: A new optical magnetometer based on index enhanced media

    Science.gov (United States)

    Scully, Marlan O.; Fleischauer, Michael; Graf, Martin

    1993-01-01

    An optical magnetometer based on quantum coherence and interference effects in atoms is proposed. The sensitivity of this device is potentially superior to the present state-of-the-art devices. Optimum operating conditions are derived, and a comparison to standard optical pumping magnetometers is made.

  10. Power flow control using distributed saturable reactors

    Science.gov (United States)

    Dimitrovski, Aleksandar D.

    2016-02-13

    A magnetic amplifier includes a saturable core having a plurality of legs. Control windings wound around separate legs are spaced apart from each other and connected in series in an anti-symmetric relation. The control windings are configured in such a way that a biasing magnetic flux arising from a control current flowing through one of the plurality of control windings is substantially equal to the biasing magnetic flux flowing into a second of the plurality of control windings. The flow of the control current through each of the plurality of control windings changes the reactance of the saturable core reactor by driving those portions of the saturable core that convey the biasing magnetic flux in the saturable core into saturation. The phasing of the control winding limits a voltage induced in the plurality of control windings caused by a magnetic flux passing around a portion of the saturable core.

  11. Construction and Operation of a Differential Hall Element Magnetometer

    Science.gov (United States)

    Calkins, Matthew W.; Javernick, Philip D.; Quintero, Pedro A.; Calm, Yitzi M.; Meisel, Mark W.

    2012-02-01

    A Differential Hall Element Magnetometer (DHEM) was constructed to measure the magnetic saturation and coercive fields of small samples consisting of magnetic nanoparticles that may have biomedical applications. The device consists of two matched Hall elements that can be moved through the room temperature bore of a 9 Tesla superconducting magnet. The Hall elements are wired in opposition such that a null response, to within a small offset, is measured in the absence of a sample that may be located on top of one unit. A LabVIEW program controls the current through the Hall elements and measures the net Hall voltage while simultaneously moving the probe through the magnetic field by regulating a linear stepper motor. Ultimately, the system will be tested to obtain a figure of merit using successively smaller samples. Details of the apparatus will be provided along with preliminary data.

  12. A dumbbell-shaped hybrid magnetometer operating in DC-10 kHz

    Science.gov (United States)

    Shi, Hongyu; Wang, Yanzhang; Chen, Siyu; Lin, Jun

    2017-12-01

    This study is motivated by the need to design a hybrid magnetometer operating in a wide-frequency band from DC to 10 kHz. To achieve this objective, a residence times difference fluxgate magnetometer (RTDFM) and an induction magnetometer (IM) have been integrated into a compact form. The hybrid magnetometer has a dumbbell-shaped structure in which the RTDFM transducer is partially inserted into the tube cores of the IM. Thus, the sensitivity of the RTDFM is significantly improved due to the flux amplification. The optimal structure, which has maximum sensitivity enhancement, was obtained through FEM analysis. To validate the theoretical analysis, the optimal hybrid magnetometer was manufactured, and its performance was evaluated. The device has a sensitivity of 45 mV/nT at 1 kHz in IM mode and 0.38 μs/nT in RTDFM mode, which is approximately 3.45 times as large as that of the single RTDFM structure. Furthermore, to obtain a lower noise performance in the entire frequency band, two operation modes switch at the cross frequency (0.16 Hz) of their noise levels. The noise level is 30 pT/√Hz in RTDFM mode and 0.07 pT/√Hz at 1 kHz in IM mode.

  13. Automatic magnetometer calibration with small space coverage

    Science.gov (United States)

    Wahdan, Ahmed

    The use of a standalone Global Navigation Satellite System (GNSS) has proved to be insufficient when navigating indoors or in urban canyons due to multipath or obstruction. Recent technological advances in low cost micro-electro-mechanical system (MEMS) -- based sensors (like accelerometers, gyroscopes and magnetometers) enabled the development of sensor-based navigation systems. Although MEMS sensors are low-cost, lightweight, small size, and have low-power consumption, they have complex error characteristics. Accurate computation of the heading angle (azimuth) is one of the most important aspects of any navigation system. It can be computed either by gyroscopes or magnetometers. Gyroscopes are inertial sensors that can provide the angular rate from which the heading can be calculated, however, their outputs drift with time. Moreover, the accumulated errors due to mathematical integration, performed to obtain the heading angle, lead to large heading errors. On the other hand, magnetometers do not suffer from drift and the calculation of heading does not suffer from error accumulation. They can provide an absolute heading from the magnetic north by sensing the earth's magnetic field. However, magnetometer readings are usually affected by magnetic fields, other than the earth magnetic field, and by other error sources; therefore magnetometer calibration is required to use magnetometer as a reliable source of heading in navigation applications. In this thesis, a framework for fast magnetometer calibration is proposed. This framework requires little space coverage with no user involvement in the calibration process, and does not need specific movements to be performed. The proposed techniques are capable of performing both 2-dimensional (2D) and 3-dimensional (3D) calibration for magnetometers. They are developed to consider different scenarios suitable for different applications, and can benefit from natural device movements. Some applications involve tethering the

  14. Method and apparatus utilizing ionizing and microwave radiation for saturation determination of water, oil and a gas in a core sample

    Science.gov (United States)

    Maerefat, Nicida L.; Parmeswar, Ravi; Brinkmeyer, Alan D.; Honarpour, Mehdi

    1994-01-01

    A system for determining the relative permeabilities of gas, water and oil in a core sample has a microwave emitter/detector subsystem and an X-ray emitter/detector subsystem. A core holder positions the core sample between microwave absorbers which prevent diffracted microwaves from reaching a microwave detector where they would reduce the signal-to-noise ratio of the microwave measurements. The microwave emitter/detector subsystem and the X-ray emitter/detector subsystem each have linear calibration characteristics, allowing one subsystem to be calibrated with respect to the other subsystem. The dynamic range of microwave measurements is extended through the use of adjustable attenuators. This also facilitates the use of core samples with wide diameters. The stratification characteristics of the fluids may be observed with a windowed cell separator at the outlet of the core sample. The condensation of heavy hydrocarbon gas and the dynamic characteristics of the fluids are observed with a sight glass at the outlet of the core sample.

  15. Design and simulation of MEMS capacitive magnetometer

    Science.gov (United States)

    Jyoti, Aditi, Tripathi, C. C.; Gopal, Ram

    2016-04-01

    This paper presents the design and simulation of a MEMS Capacitive Magnetometer using FEM (Finite Element Method) tool COMSOL Multiphysics 4.3b and results from this simulation are closely matched with analytically calculated results. A comb drive structure is used for actuation purpose which operates at resonant frequency of device is 11.791 kHz to achieve maximum displacement. A magnetic field in z-axis can be detected by this comb drive structure. Quality factor of MEMS capacitive magnetometer obtained is 18 and it has good linear response in the magnetic field range of 100 µT.

  16. High resolution remanent magnetization scanner for long cores

    Science.gov (United States)

    Demory, François; Quesnel, Yoann; Uehara, Minoru; Rochette, Pierre; Zylberman, William; Romey, Carole; Pignol, Laure; Andrieu-Ponel, Valérie

    2017-04-01

    Superconducting rock magnetometer reaches saturation when measuring magnetic moments higher than 5 10-5 Am2. Due to the distance of the sensor from the measurement zone, the spatial resolution is low for continuous measurements led on U channel or cores. To solve these problems, we designed a core logger dedicated to the measurement of remanent magnetizations. Based on a fluxgate sensor located very close to the sample, the spatial resolution of the core logger is infra-centimetric. The fluxgate sensor is also able to detect magnetic fields of few nT produced by magnetic moments of the order of few 10-8 Am2. As the equipment does not reach saturation, we measured isothermal remanent magnetization of highly magnetic samples. This magnetization was acquired perpendicularly to the long axis of U-channels from Cassis paleo-lake (Romey et al., 2015) and of cores from Haughton impact structure (Zylberman et al., submitted) using Halbach cylinders (Rochette et al., 2001). To interpret local magnetic fields in terms of magnetic moments, we performed an inter-calibration with the superconducting rock magnetometer and signal inversion. This development led to the filing of a patent (FR.16/53142) and is funded by the ECCOREV project MESENVIMAG. References: Rochette, P., Vadeboin, F., Clochard, L., 2001. Rock magnetic applications of Halbach cylinders. Physics of the Earth and Planetary Interiors 126, 109-117. Romey, C., Vella, C., Rochette, P., Andrieu-Ponel, V., Magnin, F., Veron, A., Talon, B., Landure, C., D'Ovidio, A.M., Delanghe, D., Ghilardi, M., Angeletti, B., 2015. Environmental imprints of landscape evolution and human activities during the Holocene in a small catchment of the Calanques Massif (Cassis, southern France). Holocene 25 (9), 1454-1469. Zylberman W., Quesnel Y., Rochette P., Osinski G. R., Marion C., Gattacceca J. (submitted to MAPS) Hydrothermally-enhanced magnetization at the center of the Haughton impact structure? (Nunavut, Canada).

  17. Digitalization of highly precise fluxgate magnetometers

    DEFF Research Database (Denmark)

    Cerman, Ales; Kuna, A.; Ripka, P.

    2005-01-01

    allowing configurations with modulator inside and outside the feedback loop. The last principle is demonstrated on the project of the fully digital fluxgate magnetometer based on the digital signal processor (DSP). The results of the presented projects are compared with recently published competitive...

  18. Vector Magnetometer Application with Moving Carriers

    Directory of Open Access Journals (Sweden)

    Andrii Prystai

    2016-12-01

    Full Text Available In magnetic prospecting the aeromagnetic survey is a widespread method used for research in large territories or in the areas with difficult access (forests, swamps, shallow waters. At present, a new type of mobile carriers – remotely piloted vehicles or drones – is becoming very common. The drones supplied by magnetometer can be also used for underground utility location (for example, steel and concrete constructions, buried power cables, to name a few. For aeromagnetic survey, obtaining of 3-component magnetic field data gives higher processing precision, so the fluxgate magnetometers (FGM seem to be the most preferable by reason of low weight, noise, power consumption and costs. During movement of FGM fixed to a drone practically permanent attitude changes in the Earth’s magnetic field arises with corresponding changes of its projection at FGM axes. Also the electromagnetic interference from the drone motor and uncontrolled oscillations of drone and suspension are the factors which limit the magnetometer sensitivity level. Aroused because of this, signals significantly exceed the expected signals from a studied object and so should be removed by proper interference filtration and use of stabilized towed construction, as well as at data processing. To find the necessary resolution threshold of a drone-portable FGM, the modeling was made to estimate magnetic field value from a small sphere about 1 cm radius at the minimal altitude of drone flight and it was shown that such a small object can be reliably detected if the FGM noise level is less than 0.15 nT. Next requirement is the necessity to decrease as much as possible the FGM power consumption with retention of low noise level. Finally, because of drone movement, the broadening of a frequency range should be done. The LEMI-026 magnetometer was developed satisfying all requirements to the drone-mounted device. The field tests were successfully performed using two of LEMI-026

  19. A Web Server for MACCS Magnetometer Data

    Science.gov (United States)

    Engebretson, Mark J.

    1998-01-01

    NASA Grant NAG5-3719 was provided to Augsburg College to support the development of a web server for the Magnetometer Array for Cusp and Cleft Studies (MACCS), a two-dimensional array of fluxgate magnetometers located at cusp latitudes in Arctic Canada. MACCS was developed as part of the National Science Foundation's GEM (Geospace Environment Modeling) Program, which was designed in part to complement NASA's Global Geospace Science programs during the decade of the 1990s. This report describes the successful use of these grant funds to support a working web page that provides both daily plots and file access to any user accessing the worldwide web. The MACCS home page can be accessed at http://space.augsburg.edu/space/MaccsHome.html.

  20. Design, Construction, and Testing of MOKE Magnetometer

    Science.gov (United States)

    Bailey, Tighe; Miller, Casey W.

    We report on the construction of a transverse magneto-optical Kerr effect (MOKE) magnetometer using various optical and electrical components. Uniquely, our MOKE magnetometer is able to sweep the magnetic field at frequencies greater than one Hz using lock in amplifiers to simultaneously sample the photodetector and the Hall sensor. The buffer of a lock-in amplifier allows for 512 samples per second, which allow us to rapidly sweep the magnetic field without loss of resolution. This drastically cuts down on the time taken per scan. To demonstrate the MOKE's capabilities, scans were performed on multiple thin film magnetic structures, both with and without significant magnetic anisotropy. We were able to measure room temperature hysteresis loops of ferromagnets, such as Ni80Fe20. Our sample rotation capabilities allowed us to study the angular dependence of the exchange and magnetocrystalline anisotropy in bilayer structures. Supported by NSF 1515677.

  1. A Miniature Wide Band Atomic Magnetometer

    Science.gov (United States)

    2011-12-01

    current circuit is easiest to explain if we at first ignore the capacitors . The reference and the DAC output are combined by R401 and R402 to make...atomic magnetometer CSAC – Chip scale atomic clock DAC – Digital to Analog Converter DARPA – Defense Advanced Research Projects Agency DBR...Transform FPGA – Field Programmable Gate Array GHz – Gigahertz MEMS – Micro-Electro Mechanical System MF – z-component Magnetic Quantum Number, MF MFTFM

  2. Calibration of Magnetometers with GNSS Receivers and Magnetometer-Aided GNSS Ambiguity Fixing.

    Science.gov (United States)

    Henkel, Patrick

    2017-06-08

    Magnetometers provide compass information, and are widely used for navigation, orientation and alignment of objects. As magnetometers are affected by sensor biases and eventually by systematic distortions of the Earth magnetic field, a calibration is needed. In this paper, a method for calibration of magnetometers with three Global Navigation Satellite System (GNSS) receivers is presented. We perform a least-squares estimation of the magnetic flux and sensor biases using GNSS-based attitude information. The attitude is obtained from the relative positions between the GNSS receivers in the North-East-Down coordinate frame and prior knowledge of these relative positions in the platform's coordinate frame. The relative positions and integer ambiguities of the periodic carrier phase measurements are determined with an integer least-squares estimation using an integer decorrelation and sequential tree search. Prior knowledge on the relative positions is used to increase the success rate of ambiguity fixing. We have validated the proposed method with low-cost magnetometers and GNSS receivers on a vehicle in a test drive. The calibration enabled a consistent heading determination with an accuracy of five degrees. This precise magnetometer-based attitude information allows an instantaneous GNSS integer ambiguity fixing.

  3. The atomic magnetometer: A new era in biomagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Wakai, Ronald T., E-mail: rtwakai@wisc.edu [1005 Wisconsin Institutes for Medical Research, 1111 Highland Avenue, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States)

    2014-11-07

    The high cost and impracticality of SQUID (Superconducting QUantum Interference Device) magnetometers has limited the expansion of magnetoencephalography (MEG) and magnetocardiography (MCG), especially in countries where the cost of liquid helium is high. A recent breakthrough, however, has the potential to radically change this situation. In 2003, a group at Princeton University demonstrated an atomic magnetometer, known as the SERF (spin-exchange free relaxation) magnetometer, with unprecedented sensitivity. Since then, several research groups have utilized SERF magnetometers to record MEG, MCG, and fetal MCG signals. Despite some modest drawbacks, it now seems almost certain that SERF magnetometers can replace SQUIDs for many applications. With a price tag that is likely to be far less than that of SQUIDs, SERF magnetometers can propel the next wave of growth in biomagnetism.

  4. In-orbit magnetometer bias and scale factor calibration

    Directory of Open Access Journals (Sweden)

    Hajiyev Chingiz

    2016-01-01

    Full Text Available Magnetometers are widely used for LEO small satellites attitude determination and control system. In order to estimate satellite dynamics and control attitude accurately, scale factor and bias of magnetometer must be estimated. In this study a linear Kalman filter (LKF based algorithm for the estimation of magnetometer biases and scale factors is proposed. Proposed algorithms are simulated through attitude dynamics of a small satellite.

  5. Solid-state magnetometer using electrically detected magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Jander, A., E-mail: jander@eecs.oregonstate.ed [Oregon State University, Corvallis, OR 97331 (United States); Dhagat, P. [Oregon State University, Corvallis, OR 97331 (United States)

    2010-05-15

    A silicon-based magnetometer utilizing spin-dependent recombination to electrically detect electron spin resonance is described. Electronic tracking of the resonant frequency provides an absolute, calibration-free measure of the magnetic field. The magnetometer can potentially be implemented entirely in conventional complementary metal-oxide-semiconductor (CMOS) integrated circuit technology. Based on published results for spin-dependent recombination in semiconductor diodes, an estimate of the achievable sensitivity and power consumption of an integrated magnetometer is derived.

  6. Magnetometer Data in the Classroom as a part of the NASA THEMIS Satellite Mission

    Science.gov (United States)

    Peticolas, L. M.; Bean, J.; Walker, A.

    2011-12-01

    The NASA-funded THEMIS mission was designed to determine the onset time and location of magnetic substorms of Earth's space environment, a prerequisite to understanding space weather. THEMIS is an acronym for Time History of Events and Macroscale Interactions during Substorms. he Geomagnetic Event Observation Network by Students (GEONS) project was the flagship, formal education component of the E/PO program. With the placement of magnetometers in the proximity of rural schools throughout the country, middle and high school teachers along with their students benefited from the opportunity to work with 'real-time' data and participated in hands-on space science activities. Particular attention was paid to placing the magnetometer stations at schools in rural communities whose students were traditionally underserved and underrepresented in the sciences. The project offered to the teachers of these students long-term professional development opportunities that centered around THEMIS-related space science and the magnetometer data. The THEMIS E/PO final evaluation report for the main phase of the THEMIS mission covered the period from 2003-2009, describing the impact of this program such as this program placed magnetometers sites at 13 rural, underserved schools/communities, two-fifths of which are on tribal lands; and provided intensive professional development for 20 teachers from 2004 through 2009. A core group of eight teachers estimated reaching more than 2,720 students with THEMIS-related materials/ideas. 75% of these students are minorities in science. Core teachers provided evidence of the project's positive impact on students' attitudes toward science and their choices for courses that position them for STEM-related careers. Core teachers reported sharing THEMIS-related materials/ideas with 275 colleagues. The NewsHour with Jim Lehrer featured the Petersburg, Alaska site potentially reaching more than 5 million viewers in two airings, according to Nielsen

  7. Facts about saturated fats

    Science.gov (United States)

    ... fat diary with low-fat or nonfat milk, yogurt, and cheese. Eat more fruits, vegetables, whole grains, and other foods with low or no saturated fat. Alternative Names Cholesterol - saturated fat; Atherosclerosis - saturated fat; Hardening of the ...

  8. Saturated fat (image)

    Science.gov (United States)

    Saturated fat can raise blood cholesterol and can put you at risk for heart disease and stroke. You should ... limit any foods that are high in saturated fat. Sources of saturated fat include whole-milk dairy ...

  9. Quantitative 1D saturation profiles on chalk by NMR

    DEFF Research Database (Denmark)

    Olsen, Dan; Topp, Simon; Stensgaard, Anders

    1996-01-01

    Quantitative one-dimensional saturation profiles showing the distribution of water and oil in chalk core samples are calculated from NMR measurements utilizing a 1D CSI spectroscopy pulse sequence. Saturation profiles may be acquired under conditions of fluid flow through the sample. Results reveal...... that strong saturation gradients exist in chalk core samples after core floods, due to capillary effects. The method is useful in analysis of corefloods, e.g., for determination of capillary pressure functions...

  10. Digital Fluxgate Magnetometer for Detection of Microvibration

    Directory of Open Access Journals (Sweden)

    Menghui Zhi

    2017-01-01

    Full Text Available In engineering practice, instruments, such as accelerometer and laser interferometer, are widely used in vibration measurement of structural parts. A method for using a triaxial fluxgate magnetometer as a microvibration sensor to measure low-frequency pendulum microvibration (not translational vibration is proposed in this paper, so as to detect vibration from low-frequency vibration sources, such as large rotating machine, large engineering structure, earthquake, and microtremor. This method provides vibration detection based on the environmental magnetic field signal to avoid increased measurement difficulty and error due to different relative positions of permanent magnet and magnetometer on the device under test (DUT when using the original magnetic measurement method. After fixedly connecting the fluxgate probe with the DUT during the test, the angular displacement due to vibration can be deduced by measuring the geomagnetic field’s magnetic induction intensity change on the orthogonal three components during the vibration. The test shows that the microvibration sensor has angular resolution of over 0.05° and maximum measuring frequency of 64 Hz. As an exploring test aimed to detect the microvibration of earth-orbiting satellite in the in-orbit process, the simulation experiment successfully provides the real-time microvibration information for attitude and orbit control subsystem.

  11. Continuous reading SQUID magnetometer and its applications

    Science.gov (United States)

    Janů, Zdeněk; Soukup, František

    2017-06-01

    We show a continuous reading superconducting quantum interference detector magnetometer used to measure the magnetic moment of small samples of materials as a function of an applied magnetic field, temperature, and time. A sample is held stationary while the magnetic field and sample temperature may be varied continuously in an arbitrary way, determined by the user. The applied field range is ±25 mT and the temperature range is 4.2-150 K. The advantage of a stationary sample technique is that the sample is not exposed to variations in the magnetic field or temperature, which may set in when the sample is moving. An evaluation of the measurements is not bound by the dipolar magnetic moment of the sample. High linearity of the detection system, low harmonic distortion of the applied time-varying magnetic field, and precise sample temperature control make this device suitable for studies of phase transitions, hysteretic phenomena, and nonlinear phenomena in magnetic materials and superconductors. The magnetometer's sensitivity (noise floor), i.e., magnetic moment noise spectral density, is 10 pA m2 Hz-1/2 in the white noise region.

  12. Self-Compensating Excitation of Fluxgate Sensors for Space Magnetometers

    DEFF Research Database (Denmark)

    Cerman, Alec; Merayo, José M.G.; Brauer, Peter

    2008-01-01

    of the most crucial points, continuous by design of the self-compensating excitation unit and concludes with unit complex testing and application to the magnetometer. The application of the self-compensation of the excitation decreases temperature drift of the magnetometer offset caused by the temperature...... drift of the sensor (dominant source of the offset drift) by factor of 7....

  13. Internet Access to ISEE-1 and 2 Magnetometer Data

    Science.gov (United States)

    1997-01-01

    It is reported that the entire ISEE-1 and -2 magnetometer data are placed on-line, using an 8 Gbyte disk drive. The data are stored at 4-s and 60-s resolution. Also, an interactive world wide web page, which allows to plot, on request, any interval for which magnetometer data are available, is developed.

  14. Digital fluxgate magnetometer for the "Astrid-2" satellite

    DEFF Research Database (Denmark)

    Pedersen, Erik Bøje; Primdahl, Fritz; Petersen, Jan Raagaard

    1999-01-01

    The design and performance of the Astrid-2 magnetometer are described. The magnetometer uses mathematical routines implemented by software for commercially available digital dignal processors to determine the magnetic field from the fluxgate sensor. The sensor is from the latest generation of amo...

  15. Automated system for the calibration of magnetometers

    DEFF Research Database (Denmark)

    Petrucha, Vojtech; Kaspar, Petr; Ripka, Pavel

    2009-01-01

    University. There are three axes of rotation in this design (compared to two axes in the previous version). The addition of the third axis allows us to calibrate more complex devices. An electronic compass based on a vector fluxgate magnetometer and micro electro mechanical systems (MEMS) accelerometer...... is one example. The new platform can also be used to evaluate the parameters of the compass in all possible variations in azimuth, pitch, and roll. The system is based on piezoelectric motors, which are placed on a platform made of aluminum, brass, plastic, and glass. Position sensing is accomplished...... through custom-made optical incremental sensors. The system is controlled by a microcontroller, which executes commands from a computer. The properties of the system as well as calibration and measurement results will be presented. ©2009 American Institute of Physics...

  16. High transition-temperature SQUID magnetometers and practical applications

    Energy Technology Data Exchange (ETDEWEB)

    Dantsker, Eugene [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-05-01

    The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa2Cu3O7-x (YBCO) are described. Essential to the achieving high magnetic field resolution at low frequencies is the elimination of 1/f flux noise due to thermally activated hopping of flux vortices between pinning sites in the superconducting films. Through improvements in processing, 1/f noise in single layer YBCO thin films and YBCO-SrTiO3-YBCO trilayers was systematically reduced to allow fabrication of sensitive SQUID magnetometers. Both single-layer directly coupled SQUID magnetometers and multilayer magnetometers were fabricated, based on the dc SQUID with bicrystal grain boundary Josephson junctions. Multilayer magnetometers had a lower magnetic field noise for a given physical size due to greater effective sensing areas. A magnetometer consisting of a SQUID inductively coupled to the multiturn input coil of a flux transformer in a flip-chip arrangement had a field noise of 27 fT Hz-1/2 at 1 Hz and 8.5 fT Hz-1/2 at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz-1/2 at 1 Hz and 18 fT Hz-1/2 at 1 kHz. A three-axis SQUID magnetometer for geophysical applications was constructed and operated in the field in the presence of 60 Hz and radiofrequency noise. Clinical quality magnetocardiograms were measured using multilayer SQUID magnetometers in a magnetically shielded room.

  17. VOYAGER 2 SATURN MAGNETOMETER RESAMPLED DATA 48.0 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 2 Saturn encounter magnetometer data that have been resampled at a 48.0 second sample rate. The data set is composed of 6 columns: 1)...

  18. VOYAGER 2 JUPITER MAGNETOMETER RESAMPLED DATA 9.60 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 2 Jupiter encounter magnetometer data that have been resampled at a 9.6 second sample rate. The data set is composed of 6 columns: 1)...

  19. VOYAGER 1 JUPITER MAGNETOMETER RESAMPLED DATA 9.60 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 1 Jupiter encounter magnetometer data that have been resampled at a 9.6 second sample rate. The data set is composed of 6 columns: 1)...

  20. VOYAGER 1 SATURN MAGNETOMETER RESAMPLED DATA 1.92 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 1 Saturn encounter magnetometer data that have been resampled at a 1.92 second sample rate. The data set is composed of 6 columns: 1)...

  1. VOYAGER 2 JUPITER MAGNETOMETER RESAMPLED DATA 1.92 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 2 Jupiter encounter magnetometer data that have been resampled at a 1.92 second sample rate. The data set is composed of 6 columns: 1)...

  2. VOYAGER 2 SATURN MAGNETOMETER RESAMPLED DATA 9.60 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 2 Saturn encounter magnetometer data that have been resampled at a 9.6 second sample rate. The data set is composed of 6 columns: 1)...

  3. VOYAGER 2 JUPITER MAGNETOMETER RESAMPLED DATA 48.0 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 2 Jupiter encounter magnetometer data that have been resampled at a 48.0 second sample rate. The data set is composed of 6 columns: 1)...

  4. VOYAGER 1 SATURN MAGNETOMETER RESAMPLED DATA 48.0 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 1 Saturn encounter magnetometer data that have been resampled at a 48.0 second sample rate. The data set is composed of 6 columns: 1)...

  5. VOYAGER 2 SATURN MAGNETOMETER RESAMPLED DATA 1.92 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 2 Saturn encounter magnetometer data that have been resampled at a 1.92 second sample rate. The data set is composed of 6 columns: 1)...

  6. VOYAGER 1 JUPITER MAGNETOMETER RESAMPLED DATA 48.0 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 1 Jupiter encounter magnetometer data that have been resampled at a 48.0 second sample rate. The data set is composed of 6 columns: 1)...

  7. VOYAGER 1 JUPITER MAGNETOMETER RESAMPLED DATA 1.92 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 1 Jupiter encounter magnetometer data that have been resampled at a 1.92 second sample rate. The data set is composed of 6 columns: 1)...

  8. VOYAGER 1 SATURN MAGNETOMETER RESAMPLED DATA 9.60 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 1 Saturn encounter magnetometer data that have been resampled at a 9.6 second sample rate. The data set is composed of 6 columns: 1)...

  9. Differential Search Coils Based Magnetometers: Conditioning, Magnetic Sensitivity, Spatial Resolution

    Directory of Open Access Journals (Sweden)

    Timofeeva Maria

    2012-03-01

    Full Text Available A theoretical and experimental comparison of optimized search coils based magnetometers, operating either in the Flux mode or in the classical Lenz-Faraday mode, is presented. The improvements provided by the Flux mode in terms of bandwidth and measuring range of the sensor are detailed. Theory, SPICE model and measurements are in good agreement. The spatial resolution of the sensor is studied which is an important parameter for applications in non destructive evaluation. A general expression of the magnetic sensitivity of search coils sensors is derived. Solutions are proposed to design magnetometers with reduced weight and volume without degrading the magnetic sensitivity. An original differential search coil based magnetometer, made of coupled coils, operating in flux mode and connected to a differential transimpedance amplifier is proposed. It is shown that this structure is better in terms of volume occupancy than magnetometers using two separated coils without any degradation in magnetic sensitivity. Experimental results are in good agreement with calculations.

  10. Self-Calibrating Vector Helium Magnetometer (SVHM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I SBIR proposal describes proposed development of a conceptual design for a Self-Calibrating Vector Helium Magnetometer (SVHM) for design and fabrication...

  11. High-Range Scalar Helium Magnetometer (HSHM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I proposal describes development of a conceptual design for a High-range Scalar Helium Magnetometer (HSHM) for the field range +/-16 Gauss. The HSHM...

  12. Correcting GOES-R Magnetometer Data for Stray Fields

    Science.gov (United States)

    Carter, Delano; Freesland, Douglas; Tadikonda, Sivakumara K.; Kronenwetter, Jeffrey; Todirita, Monica; Dahya, Melissa; Chu, Donald

    2016-05-01

    Time-varying spacecraft magnetic fields, i.e. stray fields, are a problem for magnetometer systems. While constant fields can be removed by calibration, stray fields are difficult to distinguish from ambient field variations. Putting two magnetometers on a long boom and solving for both the ambient and stray fields can help, but this gradiometer solution is more sensitive to noise than a single magnetometer. As shown here for the R-series Geostationary Operational Environmental Satellites (GOES-R), unless the stray fields are larger than the noise, simply averaging the two magnetometer readings gives a more accurate solution. If averaging is used, it may be worthwhile to estimate and remove stray fields explicitly. Models and estimation algorithms to do so are provided for solar array, arcjet and reaction wheel fields.

  13. GALILEO ORBITER JUPITER RAW MAGNETOMETER DATA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains raw magnetic field data acquired by the Galileo Orbiter magnetometer at Jupiter. The data set covers the time period from 1995-11-06T00:21:30...

  14. Self-Calibrating Vector Helium Magnetometer (SVHM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase 2 SBIR proposal describes the design, fabrication and calibration of a brass-board Self-Calibrating Vector Helium Magnetometer (SVHM). The SVHM instrument...

  15. Low-Fiend Vector Magnetometer (V-400-LF) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This 2010 NASA SBIR Phase 1 proposal for an innovative Low-Field Vector Magnetometer (V-400-LF) is a response to subtopic S1.06 Particles and Field Sensors and...

  16. Real-Time Hand-Held Magnetometer Array

    Science.gov (United States)

    2016-04-01

    Time Magnetometer Array Geometrics ix 1.3 LIST OF ACRONYMS ADC – Analog to Digital Converter AFE – Analog Front End AGC – Automatic Gain...automatically and in real time. Linear arrays of magnetometer sensors have been deployed in many scenarios in unexploded ordnance (UXO) detection. These have...past or over a target. This leads to various positioning and time changing errors, which limits the accuracy of the device. However, linear arrays

  17. Ultra-sensitive Magnetic Microscopy with an Atomic Magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Jin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-19

    The PowerPoint presentation focused on research goals, specific information about the atomic magnetometer, response and resolution factors of the SERF magnetometer, FC+AM systems, tests of field transfer and resolution on FC, gradient cancellation, testing of AM performance, ideas for a multi-channel AM, including preliminary sensitivity testing, and a description of a 6 channel DAQ system. A few ideas for future work ended the presentation.

  18. Detection Range of Airborne Magnetometers in Magnetic Anomaly Detection

    OpenAIRE

    Chengjing Li; Shucai Huang; Daozhi Wei; Yu Zhong; K. Y. Gong

    2015-01-01

    Airborne magnetometers are utilized for the small-range search, precise positioning, and identification of the ferromagnetic properties of underwater targets. As an important performance parameter of sensors, the detection range of airborne magnetometers is commonly set as a fixed value in references regardless of the influences of environment noise, target magnetic properties, and platform features in a classical model to detect airborne magnetic anomalies. As a consequence, devi...

  19. Man-Portable Simultaneous Magnetometer and EM System (MSEMS)

    Science.gov (United States)

    2008-12-01

    75 Hz and aliasing at 15 Hz. This is expected, and is removed with a notch filter ...distribution of weight (indeed, in the photo at YPG below, the gray bulge behind the magnetometer is a gallon jug of water used as ballast). The EM61 battery...we chop it out with a notch filter . These figures show that MSEMS’ interleaving magnetometer period counter was functioning as expected. 12

  20. Calibration of the fluxgate CSC vector magnetometers

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Risbo, Torben; Primdahl, Fritz

    1995-01-01

    found. The non-linearity is less than 4.0 ppm, taking into account that the coil facility where the magnetometer has been scanned has a very low noise (0.5 nT p-p) but not sufficient low to precise much more in this parameter. There is no non-linearity over the entire temperature range. The sensor...... offsets are less than 2.0 nT and 10.0 nT for the flight and flight spare electronics, respectively. They have been determinated by two procedures which give consistant results. Firstly, as output in the spherical harmonic method, and secondly, by rotation of the CSC sensor by 180° in two axes. It does...... not change with temperature. The sensitivities are different in each axis, due to the fact that any ADC has its own oltage reference and there is a slight difference between them. They change linearly with temperature. The temperature coefficient for each sensor is different since the radius of the feedback...

  1. 3D magnetometer for a dilution refrigerator

    Science.gov (United States)

    Uchaikin, S.; Likhachev, A.; Cioata, F.; Perminov, I.; Sanghera, H.; Singh, I.; Spear, P.; Chavez, P.; Han, X.; Petroff, C.; Rich, C.

    2012-12-01

    In this report, we describe a development of a three dimensional system for measurements of magnetic field at a wide temperature range of 300K-4K. The system is based on 8 AMR sensors and allows for control of the magnetic environment in a dilution refrigerator during the cool down of a superconducting processor. With a low noise signal processing electronics and a special sensor saturation circuit, a magnetic induction resolution below of 1 nT was achieved.

  2. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  3. An improved proton magnetometer for Earth's magnetic field observation

    Science.gov (United States)

    Xiao, Chengyu; Zhang, Shuang; Guo, Xin; Fu, Haoyang

    2015-09-01

    As a precision instrument to measure the earth magnetic field, proton magnetometer is widely used in different fields such as geological survey, buried objects detection and earth field variations. Due to poor signal to noise ratio (SNR) of the system, proton magnetometer suffers from low sensitivity which directly affects the performance. In order to increase the sensitivity, we present an improved proton magnetometer. First, the effect of matching resistance on Q value is discussed to enhance SNR, and high matching resistance has been chosen to improve the Q value of the resonant circuit. Second, noise induced by pre-amplifier is investigated in order to obtain low noise signal, and we adopt the JFET with noise figure less than 0.5dB as the pre-amplifier. Third, by using band-pass filter, low-noise output signal is obtained. Fourth, the method of period measurement based on CPLD is employed to measure frequency of the square wave shaped from the output sinusoidal signal. High precision temperature compensate crystal oscillator (TCXO) has been used to improve the frequency measurement accuracy. Last, experimental data is obtained through field measurements. By calculating the standard deviation, the sensitivity of the improved proton magnetometer is 0.15nT for Earth's magnetic field observation. Experimental results show that the new magnetometer is sensitive to earth field measurement.

  4. An improved RF circuit for Overhauser magnetometer excitation

    Science.gov (United States)

    Zheng, Di; Zhang, Shuang; Guo, Xin; Fu, Haoyang

    2015-08-01

    Overhauser magnetometer is a high-precision device for magnetostatic field measurement, which can be used in a wide variety of purposes: UXO detection, pipeline mapping and other engineering and environmental applications. Traditional proton magnetometer adopts DC polarization, suffering from low polarization efficiency, high power consumption and low signal noise ratio (SNR). Compared with the traditional proton magnetometer, nitroxide free radicals are used for dynamic nuclear polarization (DNP) to enhance nuclear magnetic resonance (NMR). RF excitation is very important for electron resonance in nitrogen oxygen free radical solution, and it is primarily significant for the obtention of high SNR signal and high sensitive field observation. Therefore, RF excitation source plays a crucial role in the development of Overhauser magnetometer. In this paper, an improved design of a RF circuit is discussed. The new RF excitation circuit consists of two parts: Quartz crystal oscillator circuit and RF power amplifier circuit. Simulation and optimization designs for power amplifier circuit based on software ADS are presented. Finally we achieve a continuous and stable sine wave of 60MHz with 1-2.5 W output power, and the second harmonic suppression is close to -20dBc. The improved RF circuit has many merits such as small size, low-power consumption and high efficiency, and it can be applied to Overhauser magnetometer to obtain high sensitive field observation.

  5. Magnetometer with a miniature transducer and automatic scanning

    Science.gov (United States)

    Debnam, W. J. J.; Fales, C. L., Jr.; Breckenridge, R. A.; Pohm, A. V. (Inventor)

    1978-01-01

    The magnetometer is based on the time variation of the magnetic permeability in the magnetic material of its transducer; however, its operation is substantially different from the ordinary flux-gate magnetometer. The transducer uses 0.05 mm diameter plated magnetic wire and is made flat enabling it to make measurements of transverse magnetic fields as close as 0.08 mm from the surface, and it has very good spatial resolution because of its small active region of approximately 0.64 mm by 0.76 mm. The magnetometer uses an inexpensive clip-on millimeter for driving and processing the electrical signals and readout. It also utilizes an automatic scanning technique which is made possible by a specially designed transducer holding mechanism that replaces the ink pen on an X-Y recorder.

  6. Design and Analyses of a MEMS Based Resonant Magnetometer

    Directory of Open Access Journals (Sweden)

    Dahai Ren

    2009-09-01

    Full Text Available A novel design of a MEMS torsional resonant magnetometer based on Lorentz force is presented and fabricated. The magnetometer consists of a silicon resonator, torsional beam, excitation coil, capacitance plates and glass substrate. Working in a resonant condition, the sensor’s vibration amplitude is converted into the sensing capacitance change, which reflects the outside magnetic flux-density. Based on the simulation, the key structure parameters are optimized and the air damping effect is estimated. The test results of the prototype are in accordance with the simulation results of the designed model. The resolution of the magnetometer can reach 30 nT. The test results indicate its sensitivity of more than 400 mV/μT when operating in a 10 Pa vacuum environment.

  7. NQR detection of explosive simulants using RF atomic magnetometers

    Science.gov (United States)

    Monti, Mark C.; Alexson, Dimitri A.; Okamitsu, Jeffrey K.

    2016-05-01

    Nuclear Quadrupole Resonance (NQR) is a highly selective spectroscopic method that can be used to detect and identify a number of chemicals of interest to the defense, national security, and law enforcement community. In the past, there have been several documented attempts to utilize NQR to detect nitrogen bearing explosives using induction sensors to detect the NQR RF signatures. We present here our work on the NQR detection of explosive simulants using optically pumped RF atomic magnetometers. RF atomic magnetometers can provide an order of magnitude (or more) improvement in sensitivity versus induction sensors and can enable mitigation of RF interference, which has classically has been a problem for conventional NQR using induction sensors. We present the theory of operation of optically pumped RF atomic magnetometers along with the result of laboratory work on the detection of explosive simulant material. An outline of ongoing work will also be presented along with a path for a fieldable detection system.

  8. Assessing and ensuring GOES-R magnetometer accuracy

    Science.gov (United States)

    Carter, Delano; Todirita, Monica; Kronenwetter, Jeffrey; Dahya, Melissa; Chu, Donald

    2016-05-01

    The GOES-R magnetometer subsystem accuracy requirement is 1.7 nanoteslas (nT). During quiet times (100 nT), accuracy is defined as absolute mean plus 3 sigma error per axis. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma error per axis. Error comes both from outside the magnetometers, e.g. spacecraft fields and misalignments, as well as inside, e.g. zero offset and scale factor errors. Because zero offset and scale factor drift over time, it will be necessary to perform annual calibration maneuvers. To predict performance before launch, we have used Monte Carlo simulations and covariance analysis. With the proposed calibration regimen, both suggest that the magnetometer subsystem will meet its accuracy requirements.

  9. Synthesis and characterization of Fe3O4@Ag core-shell: structural, morphological, and magnetic properties

    Directory of Open Access Journals (Sweden)

    Mahdi Ghazanfari

    2014-12-01

    Full Text Available This paper is a report on the synthesis of the Fe3O4@Ag core-shell with high saturation magnetization of magnetite nanoparticles as the core, by using polyol route and silver shell by chemical reduction. X-ray diffraction (XRD and Fourier transform infrared spectroscopy analyses confirmed that the particles so produced were monophase. The magnetic properties of the product were investigated by using a vibrating sample magnetometer. Magnetic saturation of magnetite was 91 emu/g that around about bulk magnetization. This high saturation magnetization can be attributed to the thin dead layer. By using polyethylene glycol as a surfactant to separate and restrict the growth of the particles, magnetostatic interactions are in good agreement with the remanence ratio analysis. Morphology and the average size of the particles were determined with field emission scanning electron microscope (FESEM. Spherical aggregates of Fe3O4 (size around 73 nm are composed of a small primary particle size of about 16 nm. Silver deposition was done using butylamine as the reductant of AgNO3 in ethanol with different ratio. The silver layers were estimated using statistical histogram images of FESEM. Silver-coated iron oxide nanohybrids have been used in a broad range of applications, including chemical and biological sensing, due to the broad absorption in the optical region associated with localized surface plasmon resonance.

  10. Observations of interplanetary dust by the Juno magnetometer investigation

    DEFF Research Database (Denmark)

    Benn, Mathias; Jørgensen, John Leif; Denver, Troelz

    2017-01-01

    One of the Juno magnetometer investigation's star cameras was configured to search for unidentified objects during Juno's transit en route to Jupiter. This camera detects and registers luminous objects to magnitude 8. Objects persisting in more than five consecutive images and moving with an appa......One of the Juno magnetometer investigation's star cameras was configured to search for unidentified objects during Juno's transit en route to Jupiter. This camera detects and registers luminous objects to magnitude 8. Objects persisting in more than five consecutive images and moving...

  11. Microfabricated optically pumped magnetometer arrays for biomedical imaging

    Science.gov (United States)

    Perry, A. R.; Sheng, D.; Krzyzewski, S. P.; Geller, S.; Knappe, S.

    2017-02-01

    Optically-pumped magnetometers have demonstrated magnetic field measurements as precise as the best superconducting quantum interference device magnetometers. Our group develops miniature alkali atom-based magnetic sensors using microfabrication technology. Our sensors do not require cryogenic cooling, and can be positioned very close to the sample, making these sensors an attractive option for development in the medical community. We will present our latest chip-scale optically-pumped gradiometer developed for array applications to image magnetic fields from the brain noninvasively. These developments should lead to improved spatial resolution, and potentially sensitive measurements in unshielded environments.

  12. Calibration of the Ørsted vector magnetometer

    DEFF Research Database (Denmark)

    Olsen, Nils; Tøffner-Clausen, Lars; Sabaka, T.J.

    2003-01-01

    The vector fluxgate magnetometer of the Orsted satellite is routinely calibrated by comparing its output with measurements of the absolute magnetic intensity from the Overhauser instrument, which is the second magnetometer of the satellite. We describe the method used for and the result obtained ...... coordinate system and the reference system of the star imager. This is done by comparing the magnetic and attitude measurements with a model of Earth's magnetic field. The Euler angles describing this rotation are determined in this way with an accuracy of better than 4 arcsec....

  13. Associating ground magnetometer observations with current or voltage generators

    DEFF Research Database (Denmark)

    Hartinger, M. D.; Xu, Z.; Clauer, C. R.

    2017-01-01

    .”Statistical studies of ground magnetometer observations associated with dayside Transient High LatitudeCurrent Systems (THLCS) driven by similar mechanisms find contradictory results using this paradigm:some studies associate THLCS with voltage generators, others with current generators. We argue that mostof...... this contradiction arises from two assumptions used to interpret ground magnetometer observations:(1) measurements made at fixed position relative to the THLCS field-aligned current and (2) negligibleauroral precipitation contributions to ionospheric conductivity. We use observations and simulations toillustrate how...

  14. A 3-Axis Miniature Magnetic Sensor Based on a Planar Fluxgate Magnetometer with an Orthogonal Fluxguide

    Directory of Open Access Journals (Sweden)

    Chih-Cheng Lu

    2015-06-01

    Full Text Available A new class of tri-axial miniature magnetometer consisting of a planar fluxgate structure with an orthogonal ferromagnetic fluxguide centrally situated over the magnetic cores is presented. The magnetic sensor possesses a cruciform ferromagnetic core placed diagonally upon the square excitation coil under which two pairs of pick-up coils for in-plane field detection are allocated. Effective principles and analysis of the magnetometer for 3-D field vectors are described and verified by numerically electromagnetic simulation for the excitation and magnetization of the ferromagnetic cores. The sensor is operated by applying the second-harmonic detection technique that can verify V-B relationship and device responsivity. Experimental characterization of the miniature fluxgate device demonstrates satisfactory spatial magnetic field detection results in terms of responsivity and noise spectrum. As a result, at an excitation frequency of 50 kHz, a maximum in-plane responsivity of 122.4 V/T appears and a maximum out-of-plane responsivity of 11.6 V/T is obtained as well. The minimum field noise spectra are found to be 0.11 nT/√Hz and 6.29 nT/√Hz, respectively, in X- and Z-axis at 1 Hz under the same excitation frequency. Compared with the previous tri-axis fluxgate devices, this planar magnetic sensor with an orthogonal fluxguide provides beneficial enhancement in both sensory functionality and manufacturing simplicity. More importantly, this novel device concept is considered highly suitable for the extension to a silicon sensor made by the current CMOS-MEMS technologies, thus emphasizing its emerging applications of field detection in portable industrial electronics.

  15. Direct liquid phase deposition fabrication of waxberry-like magnetic Fe{sub 3}O{sub 4}@TiO{sub 2} core-shell microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jian, E-mail: zhengjian@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Wu, You; Zhang, Quanping; Li, Yintao [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Wang, Chengyang [Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching (Germany); Zhou, Yuanlin, E-mail: zhouyuanlin@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China)

    2016-09-15

    Magnetic Fe{sub 3}O{sub 4}@TiO{sub 2} core-shell microspheres are ideally applied in several specific fields due to their unique properties. A facile liquid phase deposition route for the fabrication of Fe{sub 3}O{sub 4}@TiO{sub 2} core-shell microspheres was developed. The core-shell structure was obtained by direct deposition of TiO{sub 2} on the surface of Fe{sub 3}O{sub 4} microspheres. The prepared products were characterized by using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). The waxberry-like microspheres were nearly spherical with diameters of about 500 nm and average shell thickness of 80 nm. The shell layer was composed of smaller primary TiO{sub 2} nanoparticles with sizes from 10 to 20 nm. A possible growth mechanism of the core-shell structure was proposed. The photo-catalytic decomposition of methylene blue and the recycling of prepared core-shell microspheres were also investigated. - Highlights: • Waxberry-like core-shell Fe3O4@TiO2 microspheres were fabricated by facile LPD route. • They have considerable saturation magnetization and small coercivity. • They can be used as recyclable photocatalyst for removal of dyestuff in aqueous solution. • The growth mechanism of the core-shell structure was proposed.

  16. Ionospheric travelling convection vortices observed by the Greenland magnetometer chain

    DEFF Research Database (Denmark)

    Kotsiaros, Stavros; Stolle, Claudia; Friis-Christensen, Eigil

    2013-01-01

    The Greenland magnetometer array continuously provides geomagnetic variometer data since the early eighties. With the polar cusp passing over it almost every day, the array is suitable to detect ionospheric traveling convection vortices (TCVs), which were rst detected by Friis-Christensen et al...

  17. Ørsted Pre-Flight Magnetometer Calibration Mission

    DEFF Research Database (Denmark)

    Risbo, T.; Brauer, Peter; Merayo, José M.G.

    2003-01-01

    modelling was developed and tested over several years and used for circle dividersted and other missions at test facilities in Europe, the United States and the Republic of South Africa. The verification of the test coil system using an Overhauser absolute scalar proton magnetometer is explained...

  18. Small Fluxgate Magnetometers: Development and Future Trends in Spain

    Directory of Open Access Journals (Sweden)

    Lucas Pérez

    2010-03-01

    Full Text Available In this paper, we give an overview of the research on fluxgate magnetometers carried out in Spain. In particular we focus in the development of the planar-type instruments. We summarize the fabrication processes and signal processing developments as well as their use in complex systems and space.

  19. Synthesis, Characterization and Cytotoxicity of Novel Multifunctional Fe3O4@SiO2@GdVO4:Dy3+ Core-Shell Nanocomposite as a Drug Carrier

    Directory of Open Access Journals (Sweden)

    Bo Li

    2016-03-01

    Full Text Available In this study, multifunctional Fe3O4@SiO2@GdVO4:Dy3+ nanocomposites were successfully synthesized via a two-step method. Their structure, luminescence and magnetic properties were characterized by X-ray diffraction (XRD, scanning electronic microscope (SEM, transmission electron microscopy (TEM, photoluminescence (PL spectra and vibrating sample magnetometer (VSM. The results indicated that the as-prepared multifunctional composites displayed a well-defined core-shell structure. The composites show spherical morphology with a size distribution of around 360 nm. Additionally, the composites exhibit high saturation magnetization (20.40 emu/g and excellent luminescence properties. The inner Fe3O4 cores and the outer GdVO4:Dy3+ layers endow the composites with good responsive magnetic properties and strong fluorescent properties, which endow the nanoparticles with great potential applications in drug delivery, magnetic resonance imaging, and marking and separating of cells in vitro.

  20. Autonomous Aeromagnetic Surveys Using a Fluxgate Magnetometer

    Directory of Open Access Journals (Sweden)

    Douglas G. Macharet

    2016-12-01

    Full Text Available Recent advances in the research of autonomous vehicles have showed a vast range of applications, such as exploration, surveillance and environmental monitoring. Considering the mining industry, it is possible to use such vehicles in the prospection of minerals of commercial interest beneath the ground. However, tasks such as geophysical surveys are highly dependent on specific sensors, which mostly are not designed to be used in these new range of autonomous vehicles. In this work, we propose a novel magnetic survey pipeline that aims to increase versatility, speed and robustness by using autonomous rotary-wing Unmanned Aerial Vehicles (UAVs. We also discuss the development of a state-of-the-art three-axis fluxgate, where our goal in this work was to refine and adjust the sensor topology and coupled electronics specifically for this type of vehicle and application. The sensor was built with two ring-cores using a specially developed stress-annealed CoFeSiB amorphous ribbon, in order to get sufficient resolution to detect concentrations of small ferrous minerals. Finally, we report on the results of experiments performed with a real UAV in an outdoor environment, showing the efficacy of the methodology in detecting an artificial ferrous anomaly.

  1. Autonomous Aeromagnetic Surveys Using a Fluxgate Magnetometer

    Science.gov (United States)

    Macharet, Douglas G.; Perez-Imaz, Héctor I. A.; Rezeck, Paulo A. F.; Potje, Guilherme A.; Benyosef, Luiz C. C.; Wiermann, André; Freitas, Gustavo M.; Garcia, Luis G. U.; Campos, Mario F. M.

    2016-01-01

    Recent advances in the research of autonomous vehicles have showed a vast range of applications, such as exploration, surveillance and environmental monitoring. Considering the mining industry, it is possible to use such vehicles in the prospection of minerals of commercial interest beneath the ground. However, tasks such as geophysical surveys are highly dependent on specific sensors, which mostly are not designed to be used in these new range of autonomous vehicles. In this work, we propose a novel magnetic survey pipeline that aims to increase versatility, speed and robustness by using autonomous rotary-wing Unmanned Aerial Vehicles (UAVs). We also discuss the development of a state-of-the-art three-axis fluxgate, where our goal in this work was to refine and adjust the sensor topology and coupled electronics specifically for this type of vehicle and application. The sensor was built with two ring-cores using a specially developed stress-annealed CoFeSiB amorphous ribbon, in order to get sufficient resolution to detect concentrations of small ferrous minerals. Finally, we report on the results of experiments performed with a real UAV in an outdoor environment, showing the efficacy of the methodology in detecting an artificial ferrous anomaly. PMID:27999307

  2. Autonomous Aeromagnetic Surveys Using a Fluxgate Magnetometer.

    Science.gov (United States)

    Macharet, Douglas G; Perez-Imaz, Héctor I A; Rezeck, Paulo A F; Potje, Guilherme A; Benyosef, Luiz C C; Wiermann, André; Freitas, Gustavo M; Garcia, Luis G U; Campos, Mario F M

    2016-12-17

    Recent advances in the research of autonomous vehicles have showed a vast range of applications, such as exploration, surveillance and environmental monitoring. Considering the mining industry, it is possible to use such vehicles in the prospection of minerals of commercial interest beneath the ground. However, tasks such as geophysical surveys are highly dependent on specific sensors, which mostly are not designed to be used in these new range of autonomous vehicles. In this work, we propose a novel magnetic survey pipeline that aims to increase versatility, speed and robustness by using autonomous rotary-wing Unmanned Aerial Vehicles (UAVs). We also discuss the development of a state-of-the-art three-axis fluxgate, where our goal in this work was to refine and adjust the sensor topology and coupled electronics specifically for this type of vehicle and application. The sensor was built with two ring-cores using a specially developed stress-annealed CoFeSiB amorphous ribbon, in order to get sufficient resolution to detect concentrations of small ferrous minerals. Finally, we report on the results of experiments performed with a real UAV in an outdoor environment, showing the efficacy of the methodology in detecting an artificial ferrous anomaly.

  3. Space magnetometer based on an anisotropic magnetoresistive hybrid sensor

    Science.gov (United States)

    Brown, P.; Whiteside, B. J.; Beek, T. J.; Fox, P.; Horbury, T. S.; Oddy, T. M.; Archer, M. O.; Eastwood, J. P.; Sanz-Hernández, D.; Sample, J. G.; Cupido, E.; O'Brien, H.; Carr, C. M.

    2014-12-01

    We report on the design and development of a low resource, dual sensor vector magnetometer for space science applications on very small spacecraft. It is based on a hybrid device combining an orthogonal triad of commercial anisotropic magnetoresistive (AMR) sensors with a totem pole H-Bridge drive on a ceramic substrate. The drive enables AMR operation in the more sensitive flipped mode and this is achieved without the need for current spike transmission down a sensor harness. The magnetometer has sensitivity of better than 3 nT in a 0-10 Hz band and a total mass of 104 g. Three instruments have been launched as part of the TRIO-CINEMA space weather mission, inter-calibration against the International Geomagnetic Reference Field model makes it possible to extract physical signals such as field-aligned current deflections of 20-60 nT within an approximately 45 000 nT ambient field.

  4. Machine Learning Based Localization and Classification with Atomic Magnetometers

    Science.gov (United States)

    Deans, Cameron; Griffin, Lewis D.; Marmugi, Luca; Renzoni, Ferruccio

    2018-01-01

    We demonstrate identification of position, material, orientation, and shape of objects imaged by a Rb 85 atomic magnetometer performing electromagnetic induction imaging supported by machine learning. Machine learning maximizes the information extracted from the images created by the magnetometer, demonstrating the use of hidden data. Localization 2.6 times better than the spatial resolution of the imaging system and successful classification up to 97% are obtained. This circumvents the need of solving the inverse problem and demonstrates the extension of machine learning to diffusive systems, such as low-frequency electrodynamics in media. Automated collection of task-relevant information from quantum-based electromagnetic imaging will have a relevant impact from biomedicine to security.

  5. Combined alternating gradient force magnetometer and susceptometer system

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, M.; Mendizábal Vázquez, I. de; Aroca, C. [Dpto. Física Aplicada, E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, Madrid 28040 (Spain); Ranchal, R. [Dpto. Física de Materiales, Facultad Ciencias Físicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, Madrid 28040 (Spain); Cobos, P. [ISOM, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, Madrid 28040 (Spain)

    2015-01-15

    We report the design, fabrication, and characterization of a new system that combines the performances of two different types of magnetic characterization systems, Alternating Gradient Force Magnetometers (AGFM) and susceptometers. The flexibility of our system is demonstrated by its capability to be used as any of them, AGFM or susceptometer, without any modification in the experimental set-up because of the electronics we have developed. Our system has a limit of sensitivity lower than 5 × 10{sup −7} emu. Moreover, its main advantage is demonstrated by the possibility of measuring small quantities of materials under DC or AC magnetic fields that cannot properly be measured with a commercial vibrating sample magnetometers or AGFM.

  6. Hansteen's magnetometer and the origin of the magnetic crusade.

    Science.gov (United States)

    Enebakk, Vidar

    2014-12-01

    In the early nineteenth century, Norwegian mathematician and astronomer Christopher Hansteen (1784-1873) contributed significantly to international collaboration in the study of terrestrial magnetism. In particular, Hansteen was influential in the origin and orientation of the magnetic lobby in Britain, a campaign which resulted in a global network of fixed geomagnetic observatories. In retrospect, however, his contribution was diminished, because his four-pole theory in Untersuchungen der Magnetismus der Erde (1819) was ultimately refuted by Carl Friedrich Gauss in Allgemeine Theorie des Erdmagnetismus (1839). Yet Hansteen's main contribution was practical rather than theoretical. His major impact was related to the circulation of his instruments and techniques. From the mid-1820s, 'Hansteen's magnetometer' was distributed all over the British Isles and throughout the international scientific community devoted to studying terrestrial magnetism. Thus in the decades before the magnetic crusade, Hansteen had established an international system of observation, standardization and representation based on measurements with his small and portable magnetometers.

  7. Space magnetometer based on an anisotropic magnetoresistive hybrid sensor.

    Science.gov (United States)

    Brown, P; Whiteside, B J; Beek, T J; Fox, P; Horbury, T S; Oddy, T M; Archer, M O; Eastwood, J P; Sanz-Hernández, D; Sample, J G; Cupido, E; O'Brien, H; Carr, C M

    2014-12-01

    We report on the design and development of a low resource, dual sensor vector magnetometer for space science applications on very small spacecraft. It is based on a hybrid device combining an orthogonal triad of commercial anisotropic magnetoresistive (AMR) sensors with a totem pole H-Bridge drive on a ceramic substrate. The drive enables AMR operation in the more sensitive flipped mode and this is achieved without the need for current spike transmission down a sensor harness. The magnetometer has sensitivity of better than 3 nT in a 0-10 Hz band and a total mass of 104 g. Three instruments have been launched as part of the TRIO-CINEMA space weather mission, inter-calibration against the International Geomagnetic Reference Field model makes it possible to extract physical signals such as field-aligned current deflections of 20-60 nT within an approximately 45,000 nT ambient field.

  8. Fiber Optic Magnetometers Using Planar And Cylindrical Magnetostrictive Transducers

    Science.gov (United States)

    Bucholtz, F.; Yurek, A. M.; Koo, K. P.; Dandridge, A.

    1987-04-01

    Fiber optic magnetometers which require high sensitivity at low frequencies (dc-10 Hz) rely on the nonlinear magnetostriction of materials such as amorphous metallic glass alloys. Typically, fiber is bonded to a magnetostrictive sample to convert strain in the sample to phase shift in a fiber interferometer. We present the results of measurements of the frequency dependence and dc and ac magnetic field sensitivity of both planar and cylindrical transducing elements, and discuss the practical advantages and disadvan-tages of each configuration.

  9. The Upgraded CARISMA Magnetometer Array in the THEMIS Era

    Science.gov (United States)

    Mann, I. R.; Milling, D. K.; Rae, I. J.; Ozeke, L. G.; Kale, A.; Kale, Z. C.; Murphy, K. R.; Parent, A.; Usanova, M.; Pahud, D. M.; Lee, E.-A.; Amalraj, V.; Wallis, D. D.; Angelopoulos, V.; Glassmeier, K.-H.; Russell, C. T.; Auster, H.-U.; Singer, H. J.

    2008-12-01

    This review describes the infrastructure and capabilities of the expanded and upgraded Canadian Array for Realtime InvestigationS of Magnetic Activity (CARISMA) magnetometer array in the era of the THEMIS mission. Formerly operated as the Canadian Auroral Network for the OPEN Program Unified Study (CANOPUS) magnetometer array until 2003, CARISMA capabilities have been extended with the deployment of additional fluxgate magnetometer stations (to a total of 28), the upgrading of the fluxgate magnetometer cadence to a standard data product of 1 sample/s (raw sampled 8 samples/s data stream available on request), and the deployment of a new network of 8 pairs of induction coils (100 samples per second). CARISMA data, GPS-timed and backed up at remote field stations, is collected using Very Small Aperture Terminal (VSAT) satellite internet in real-time providing a real-time monitor for magnetic activity on a continent-wide scale. Operating under the magnetic footprint of the THEMIS probes, data from 5 CARISMA stations at 29-30 samples/s also forms part of the formal THEMIS ground-based observatory (GBO) data-stream. In addition to technical details, in this review we also outline some of the scientific capabilities of the CARISMA array for addressing all three of the scientific objectives of the THEMIS mission, namely: 1. Onset and evolution of the macroscale substorm instability, 2. Production of storm-time MeV electrons, and 3. Control of the solar wind-magnetosphere coupling by the bow shock, magnetosheath, and magnetopause. We further discuss some of the compelling questions related to these three THEMIS mission science objectives which can be addressed with CARISMA.

  10. Venous oxygen saturation.

    Science.gov (United States)

    Hartog, Christiane; Bloos, Frank

    2014-12-01

    Early detection and rapid treatment of tissue hypoxia are important goals. Venous oxygen saturation is an indirect index of global oxygen supply-to-demand ratio. Central venous oxygen saturation (ScvO2) measurement has become a surrogate for mixed venous oxygen saturation (SvO2). ScvO2 is measured by a catheter placed in the superior vena cava. After results from a single-center study suggested that maintaining ScvO2 values >70% might improve survival rates in septic patients, international practice guidelines included this target in a bundle strategy to treat early sepsis. However, a recent multicenter study with >1500 patients found that the use of central hemodynamic and ScvO2 monitoring did not improve long-term survival when compared to the clinical assessment of the adequacy of circulation. It seems that if sepsis is recognized early, a rapid initiation of antibiotics and adequate fluid resuscitation are more important than measuring venous oxygen saturation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Metamaterial saturable absorber mirror.

    Science.gov (United States)

    Dayal, Govind; Ramakrishna, S Anantha

    2013-02-01

    We propose a metamaterial saturable absorber mirror at midinfrared wavelengths that can show a saturation of absorption with intensity of incident light and switch to a reflecting state. The design consists of an array of circular metallic disks separated by a thin film of vanadium dioxide (VO(2)) from a continuous metallic film. The heating due to the absorption in the absorptive state causes the VO(2) to transit to a metallic phase from the low temperature insulating phase. The metamaterial switches from an absorptive state (R≃0.1%) to a reflective state (R>95%) for a specific threshold intensity of the incident radiation corresponding to the phase transition of VO(2), resulting in the saturation of absorption in the metamaterial. The computer simulations show over 99.9% peak absorbance, a resonant bandwidth of about 0.8 μm at 10.22 μm wavelengths, and saturation intensity of 140 mW cm(-2) for undoped VO(2) at room temperature. We also carried out numerical simulations to investigate the effects of localized heating and temperature distribution by solving the heat diffusion problem.

  12. Polarization enhanced Nuclear Quadrupole Resonance with an atomic magnetometer

    Science.gov (United States)

    Malone, Michael W.; Barrall, Geoffrey A.; Espy, Michelle A.; Monti, Mark C.; Alexson, Dimitri A.; Okamitsu, Jeffrey K.

    2016-05-01

    Nuclear Quadrupole Resonance (NQR) has been demonstrated for the detection of 14-N in explosive compounds. Application of a material specific radio-frequency (RF) pulse excites a response typically detected with a wire- wound antenna. NQR is non-contact and material specific, however fields produced by NQR are typically very weak, making demonstration of practical utility challenging. For certain materials, the NQR signal can be increased by transferring polarization from hydrogen nuclei to nitrogen nuclei using external magnetic fields. This polarization enhancement (PE) can enhance the NQR signal by an order of magnitude or more. Atomic magnetometers (AM) have been shown to improve detection sensitivity beyond a conventional antenna by a similar amount. AM sensors are immune to piezo-electric effects that hamper conventional NQR, and can be combined to form a gradiometer for effective RF noise cancellation. In principle, combining polarization enhancement with atomic magnetometer detection should yield improvement in signal-to-noise ratio that is the product of the two methods, 100-fold or more over conventional NQR. However both methods are even more exotic than traditional NQR, and have never been combined due to challenges in operating a large magnetic field and ultra-sensitive magnetic field sensor in proximity. Here we present NQR with and without PE with an atomic magnetometer, demonstrating signal enhancement greater than 20-fold for ammonium nitrate. We also demonstrate PE for PETN using a traditional coil for detection with an enhancement factor of 10. Experimental methods and future applications are discussed.

  13. A broadband two axis flux-gate magnetometer

    Directory of Open Access Journals (Sweden)

    P. Palangio

    1998-06-01

    Full Text Available A broadband two axis flux-gate magnetometer was developed to obtain high sensitivity in magnetotelluric measurements. In magnetotelluric sounding, natural low frequency electromagnetic fields are used to estimate the conductivity of the Earth's interior. Because variations in the natural magnetic field have small amplitude(10-100 pT in the frequency range 1 Hz to 100 Hz, highly sensitive magnetic sensors are required. In magnetotelluric measurements two long and heavy solenoids, which must be installed, in the field station, perpendicular to each other (north-south and east-west and levelled in the horizontal plane are used. The coil is a critical component in magnetotelluric measurements because very slight motions create noise voltages, particularly troublesome in wooded areas; generally the installation takes place in a shallow trench. Moreover the coil records the derivative of the variations rather than the magnetic field variations, consequently the transfer function (amplitude and phase of this sensor is not constant throughout the frequency range 0.001-100 Hz. The instrument, developed at L'Aquila Geomagnetic Observatory, has a flat response in both amplitude and phase in the frequency band DC-100 Hz, in addition it has low weight, low power, small volume and it is easier to install in the field than induction magnetometers. The sensivity of this magnetometer is 10 pT rms.

  14. Detection Range of Airborne Magnetometers in Magnetic Anomaly Detection

    Directory of Open Access Journals (Sweden)

    Chengjing Li

    2015-11-01

    Full Text Available Airborne magnetometers are utilized for the small-range search, precise positioning, and identification of the ferromagnetic properties of underwater targets. As an important performance parameter of sensors, the detection range of airborne magnetometers is commonly set as a fixed value in references regardless of the influences of environment noise, target magnetic properties, and platform features in a classical model to detect airborne magnetic anomalies. As a consequence, deviation in detection ability analysis is observed. In this study, a novel detection range model is proposed on the basis of classic detection range models of airborne magnetometers. In this model, probability distribution is applied, and the magnetic properties of targets and the environment noise properties of a moving submarine are considered. The detection range model is also constructed by considering the distribution of the moving submarine during detection. A cell-averaging greatest-of-constant false alarm rate test method is also used to calculate the detection range of the model at a desired false alarm rate. The detection range model is then used to establish typical submarine search probabilistic models. Results show that the model can be used to evaluate not only the effects of ambient magnetic noise but also the moving and geomagnetic features of the target and airborne detection platform. The model can also be utilized to display the actual operating range of sensor systems.

  15. Swarm Optimization-Based Magnetometer Calibration for Personal Handheld Devices

    Directory of Open Access Journals (Sweden)

    Naser El-Sheimy

    2012-09-01

    Full Text Available Inertial Navigation Systems (INS consist of accelerometers, gyroscopes and a processor that generates position and orientation solutions by integrating the specific forces and rotation rates. In addition to the accelerometers and gyroscopes, magnetometers can be used to derive the user heading based on Earth’s magnetic field. Unfortunately, the measurements of the magnetic field obtained with low cost sensors are usually corrupted by several errors, including manufacturing defects and external electro-magnetic fields. Consequently, proper calibration of the magnetometer is required to achieve high accuracy heading measurements. In this paper, a Particle Swarm Optimization (PSO-based calibration algorithm is presented to estimate the values of the bias and scale factor of low cost magnetometers. The main advantage of this technique is the use of the artificial intelligence which does not need any error modeling or awareness of the nonlinearity. Furthermore, the proposed algorithm can help in the development of Pedestrian Navigation Devices (PNDs when combined with inertial sensors and GPS/Wi-Fi for indoor navigation and Location Based Services (LBS applications.

  16. Particle swarm optimization algorithm based low cost magnetometer calibration

    Science.gov (United States)

    Ali, A. S.; Siddharth, S., Syed, Z., El-Sheimy, N.

    2011-12-01

    Inertial Navigation Systems (INS) consist of accelerometers, gyroscopes and a microprocessor provide inertial digital data from which position and orientation is obtained by integrating the specific forces and rotation rates. In addition to the accelerometers and gyroscopes, magnetometers can be used to derive the absolute user heading based on Earth's magnetic field. Unfortunately, the measurements of the magnetic field obtained with low cost sensors are corrupted by several errors including manufacturing defects and external electro-magnetic fields. Consequently, proper calibration of the magnetometer is required to achieve high accuracy heading measurements. In this paper, a Particle Swarm Optimization (PSO) based calibration algorithm is presented to estimate the values of the bias and scale factor of low cost magnetometer. The main advantage of this technique is the use of the artificial intelligence which does not need any error modeling or awareness of the nonlinearity. The estimated bias and scale factor errors from the proposed algorithm improve the heading accuracy and the results are also statistically significant. Also, it can help in the development of the Pedestrian Navigation Devices (PNDs) when combined with the INS and GPS/Wi-Fi especially in the indoor environments

  17. Noise characterization for the FID signal from proton precession magnetometer

    Science.gov (United States)

    Liu, H.; Dong, H.; Liu, Z.; Ge, J.; Bai, B.; Zhang, C.

    2017-07-01

    Proton precession magnetometer is a high-precision device for weak magnetostatic field measurement. The measurement accuracy depends on the frequency measurement of free induction decay (FID) signal, while the signal to noise ratio (SNR) is an important factor affecting the results. Many signal processing methods have been proposed to improve the SNR of FID signal. However, the theoretical analysis of different types of noises for FID signal has not be conducted yet. In addition, the relationship between the frequency measurement accuracy and SNR has not been explicitly established and quantified. This paper first proposes a background noise model based on the extracted features from the FID signal. With this model, background noises, such as white noise, narrow-band noise, and phase noise etc., can be calculated and estimated. Secondly, the relationship between the frequency measurement accuracy and SNR is identified. We also built a prototype proton magnetometer for field tests and validation purpose. Experiments were conducted to investigate this relation through simulation. Different values for frequency accuracy were obtained with different SNRs from the acquired FID signals from field tests. The consistence between the measurement and computational results is observed. When SNR is larger than 30 dB, the absolute frequency accuracy becomes constant which is about 0.04 Hz. With the stability taken into account, the accuracy can be better even when the SNR is higher than 30 dB. This study provides a reference to optimize the design of proton precession magnetometer and the frequency calculation for FID signal.

  18. Athermal fiber laser for the SWARM absolute scalar magnetometer

    Science.gov (United States)

    Fourcault, W.; Léger, J.-M.; Costes, V.; Fratter, I.; Mondin, L.

    2017-11-01

    The Absolute Scalar Magnetometer (ASM) developed by CEA-LETI/CNES is an optically pumped 4He magnetic field sensor based on the Zeeman effect and an electronic magnetic resonance whose effects are amplified by a laser pumping process [1-2]. Consequently, the role of the laser is to pump the 4He atoms at the D0 transition as well as to allow the magnetic resonance signal detection. The ASM will be the scalar magnetic reference instrument of the three ESA Swarm satellites to be launched in 2012 in order to carry out the best ever survey of the Earth magnetic field and its temporal evolution. The sensitivity and accuracy of this magnetometer based on 4He optical pumping depend directly on the characteristics of its light source, which is the key sub-system of the sensor. We describe in this paper the selected fiber laser architecture and its wavelength stabilization scheme. Its main performance in terms of spectral emission, optical power at 1083 nm and intensity noise characteristics in the frequency bands used for the operation of the magnetometer, are then presented. Environmental testing results (thermal vacuum cycling, vibrations, shocks and ageing) are also reported at the end of this paper.

  19. A spinner magnetometer for large Apollo lunar samples

    Science.gov (United States)

    Uehara, M.; Gattacceca, J.; Quesnel, Y.; Lepaulard, C.; Lima, E. A.; Manfredi, M.; Rochette, P.

    2017-10-01

    We developed a spinner magnetometer to measure the natural remanent magnetization of large Apollo lunar rocks in the storage vault of the Lunar Sample Laboratory Facility (LSLF) of NASA. The magnetometer mainly consists of a commercially available three-axial fluxgate sensor and a hand-rotating sample table with an optical encoder recording the rotation angles. The distance between the sample and the sensor is adjustable according to the sample size and magnetization intensity. The sensor and the sample are placed in a two-layer mu-metal shield to measure the sample natural remanent magnetization. The magnetic signals are acquired together with the rotation angle to obtain stacking of the measured signals over multiple revolutions. The developed magnetometer has a sensitivity of 5 × 10-7 Am2 at the standard sensor-to-sample distance of 15 cm. This sensitivity is sufficient to measure the natural remanent magnetization of almost all the lunar basalt and breccia samples with mass above 10 g in the LSLF vault.

  20. Assaying Carcinoembryonic Antigens by Normalized Saturation Magnetization

    Science.gov (United States)

    Huang, Kai-Wen; Chieh, Jen-Jie; Shi, Jin-Cheng; Chiang, Ming-Hsien

    2015-07-01

    Biofunctionalized magnetic nanoparticles (BMNs) that provide unique advantages have been extensively used to develop immunoassay methods. However, these developed magnetic methods have been used only for specific immunoassays and not in studies of magnetic characteristics of materials. In this study, a common vibration sample magnetometer (VSM) was used for the measurement of the hysteresis loop for different carcinoembryonic antigens (CEA) concentrations ( Φ CEA) based on the synthesized BMNs with anti-CEA coating. Additionally, magnetic parameters such as magnetization ( M), remanent magnetization ( M R), saturation magnetization ( M S), and normalized parameters (Δ M R/ M R and Δ M S/ M S) were studied. Here, Δ M R and Δ M s were defined as the difference between any ΦCEA and zero Φ CEA. The parameters M, Δ M R, and Δ M S increased with Φ CEA, and Δ M S showed the largest increase. Magnetic clusters produced by the conjugation of the BMNs to CEAs showed a Δ M S greater than that of BMNs. Furthermore, the relationship between Δ M S/ M S and Φ CEA could be described by a characteristic logistic function, which was appropriate for assaying the amount of CEAs. This analytic Δ M S/ M S and the BMNs used in general magnetic immunoassays can be used for upgrading the functions of the VSM and for studying the magnetic characteristics of materials.

  1. Statistical optimization of effective parameters on saturation magnetization of nanomagnetite particles

    Science.gov (United States)

    Ramimoghadam, Donya; Bagheri, Samira; Yousefi, Amin Termeh; Abd Hamid, Sharifah Bee

    2015-11-01

    In this study, nanomagnetite particles have been successfully prepared via the coprecipitation method. The effect of the key explanatory variables on the saturation magnetization of synthetic nanomagnetite particles was investigated using the response surface methodology (RSM). The correlation of the involved parameters with the growth process was examined by employing the central composite design method through designating set up experiments that will determine the interaction of the variables. The vibrating sample magnetometer (VSM) was used to confirm the statistical analysis. Furthermore, the regression analysis monitors the priority of the variables' influence on the saturation magnetization of nanomagnetite particles by developing the statistical model of the saturation magnetization. According to the investigated model, the highest interaction of variable belongs to the pH and temperature with the optimized condition of 9-11, and 75-85 °C, respectively. The response obtained by VSM suggests that the saturation magnetization of nanomagnetite particles can be controlled by restricting the effective parameters.

  2. High-Sensitivity Low-Noise Miniature Fluxgate Magnetometers Using a Flip Chip Conceptual Design

    Directory of Open Access Journals (Sweden)

    Chih-Cheng Lu

    2014-07-01

    Full Text Available This paper presents a novel class of miniature fluxgate magnetometers fabricated on a print circuit board (PCB substrate and electrically connected to each other similar to the current “flip chip” concept in semiconductor package. This sensor is soldered together by reversely flipping a 5 cm × 3 cm PCB substrate to the other identical one which includes dual magnetic cores, planar pick-up coils, and 3-D excitation coils constructed by planar Cu interconnections patterned on PCB substrates. Principles and analysis of the fluxgate sensor are introduced first, and followed by FEA electromagnetic modeling and simulation for the proposed sensor. Comprehensive characteristic experiments of the miniature fluxgate device exhibit favorable results in terms of sensitivity (or “responsivity” for magnetometers and field noise spectrum. The sensor is driven and characterized by employing the improved second-harmonic detection technique that enables linear V-B correlation and responsivity verification. In addition, the double magnitude of responsivity measured under very low frequency (1 Hz magnetic fields is experimentally demonstrated. As a result, the maximum responsivity of 593 V/T occurs at 50 kHz of excitation frequency with the second harmonic wave of excitation; however, the minimum magnetic field noise is found to be 0.05 nT/Hz1/2 at 1 Hz under the same excitation. In comparison with other miniature planar fluxgates published to date, the fluxgate magnetic sensor with flip chip configuration offers advances in both device functionality and fabrication simplicity. More importantly, the novel design can be further extended to a silicon-based micro-fluxgate chip manufactured by emerging CMOS-MEMS technologies, thus enriching its potential range of applications in modern engineering and the consumer electronics market.

  3. High-sensitivity low-noise miniature fluxgate magnetometers using a flip chip conceptual design.

    Science.gov (United States)

    Lu, Chih-Cheng; Huang, Jeff; Chiu, Po-Kai; Chiu, Shih-Liang; Jeng, Jen-Tzong

    2014-07-30

    This paper presents a novel class of miniature fluxgate magnetometers fabricated on a print circuit board (PCB) substrate and electrically connected to each other similar to the current "flip chip" concept in semiconductor package. This sensor is soldered together by reversely flipping a 5 cm × 3 cm PCB substrate to the other identical one which includes dual magnetic cores, planar pick-up coils, and 3-D excitation coils constructed by planar Cu interconnections patterned on PCB substrates. Principles and analysis of the fluxgate sensor are introduced first, and followed by FEA electromagnetic modeling and simulation for the proposed sensor. Comprehensive characteristic experiments of the miniature fluxgate device exhibit favorable results in terms of sensitivity (or "responsivity" for magnetometers) and field noise spectrum. The sensor is driven and characterized by employing the improved second-harmonic detection technique that enables linear V-B correlation and responsivity verification. In addition, the double magnitude of responsivity measured under very low frequency (1 Hz) magnetic fields is experimentally demonstrated. As a result, the maximum responsivity of 593 V/T occurs at 50 kHz of excitation frequency with the second harmonic wave of excitation; however, the minimum magnetic field noise is found to be 0.05 nT/Hz(1/2) at 1 Hz under the same excitation. In comparison with other miniature planar fluxgates published to date, the fluxgate magnetic sensor with flip chip configuration offers advances in both device functionality and fabrication simplicity. More importantly, the novel design can be further extended to a silicon-based micro-fluxgate chip manufactured by emerging CMOS-MEMS technologies, thus enriching its potential range of applications in modern engineering and the consumer electronics market.

  4. SATURATED ZONE IN-SITU TESTING

    Energy Technology Data Exchange (ETDEWEB)

    P.W. REIMUS

    2004-11-08

    transfer coefficients, and colloid transport parameters. (4) Comparisons of sorption parameter estimates for a reactive solute tracer (lithium ion) derived from the C-wells field tracer tests and laboratory tests using C-wells core samples. (5) Sorption parameter estimates for lithium ion derived from laboratory tests using alluvium samples from ATC well NC-EWDP-19D. These estimates will allow a comparison of laboratory- and field-derived sorption parameters to be made in saturated alluvium if cross-hole tracer tests are conducted at the ATC.

  5. Saturated and trans fats

    National Research Council Canada - National Science Library

    Shader, Richard I

    2014-01-01

    ... Original Pancake Mix plus ingredients suggested by the recipe: 2 g saturated fat (SF) and no trans fatty acids or trans fat (TFA); bacon, Oscar Mayer Lower Sodium Bacon: 2.5 g SF and no TFA; sausages, Jimmy Dean Original Pork Sausage Links: 8 g SF and no TFA; potatoes, Ore-Ida Mini Tater Tots: 2 g SF and no TFA; and nondairy creamer, Nestlé Coffee-...

  6. Saturation Detection-Based Blocking Scheme for Transformer Differential Protection

    Directory of Open Access Journals (Sweden)

    Byung Eun Lee

    2014-07-01

    Full Text Available This paper describes a current differential relay for transformer protection that operates in conjunction with a core saturation detection-based blocking algorithm. The differential current for the magnetic inrush or over-excitation has a point of inflection at the start and end of each saturation period of the transformer core. At these instants, discontinuities arise in the first-difference function of the differential current. The second- and third-difference functions convert the points of inflection into pulses, the magnitudes of which are large enough to detect core saturation. The blocking signal is activated if the third-difference of the differential current is larger than the threshold and is maintained for one cycle. In addition, a method to discriminate between transformer saturation and current transformer (CT saturation is included. The performance of the proposed blocking scheme was compared with that of a conventional harmonic blocking method. The test results indicate that the proposed scheme successfully discriminates internal faults even with CT saturation from the magnetic inrush, over-excitation, and external faults with CT saturation, and can significantly reduce the operating time delay of the relay.

  7. I-DWRL: Improved Dual Wireless Radio Localization Using Magnetometer.

    Science.gov (United States)

    Aziz, Abdul; Kumar, Ramesh; Joe, Inwhee

    2017-11-15

    In the dual wireless radio localization (DWRL) technique each sensor node is equipped with two ultra-wide band (UWB) radios; the distance between the two radios is a few tens of centimeters. For localization, the DWRL technique must use at least two pre-localized nodes to fully localize an unlocalized node. Moreover, in the DWRL technique it is also not possible for two sensor nodes to properly communicate location information unless each of the four UWB radios of two communicating sensor nodes cannot approach the remaining three radios. In this paper, we propose an improved DWRL (I-DWRL) algorithm along with mounting a magnetometer sensor on one of the UWB radios of all sensor nodes. This addition of a magnetometer helps to improve DWRL algorithm such that only one localized sensor node is required for the localization of an unlocalized sensor node, and localization can also be achieved even when some of the four radios of two nodes are unable to communicate with the remaining three radios. The results show that with the use of a magnetometer a greater number of nodes can be localized with a smaller transmission range, less energy and a shorter period of time. In comparison with the conventional DWRL algorithm, our I-DWRL not only maintains the localization error but also requires around half of semi-localizations, 60% of the time, 70% of the energy and a shorter communication range to fully localize an entire network. Moreover, I-DWRL can even localize more nodes while transmission range is not sufficient for DWRL algorithm.

  8. Opportunity Science Using the Juno Magnetometer Investigation Star Trackers

    Science.gov (United States)

    Joergensen, J. L.; Connerney, J. E.; Bang, A. M.; Denver, T.; Oliversen, R. J.; Benn, M.; Lawton, P.

    2013-12-01

    The magnetometer experiment onboard Juno is equipped with four non-magnetic star tracker camera heads, two of which reside on each of the magnetometer sensor optical benches. These are located 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. The star tracker, collectively referred to as the Advanced Stellar Compass (ASC), provides high accuracy attitude information for the magnetometer sensors throughout science operations. The star tracker camera heads are pointed +/- 13 deg off the spin vector, in the anti-sun direction, imaging a 13 x 20 deg field of view every ¼ second as Juno rotates at 1 or 2 rpm. The ASC is a fully autonomous star tracker, producing a time series of attitude quaternions for each camera head, utilizing a suite of internal support functions. These include imaging capabilities, autonomous object tracking, automatic dark-sky monitoring, and related capabilities; these internal functions may be accessed via telecommand. During Juno's cruise phase, this capability can be tapped to provide unique science and engineering data available along the Juno trajectory. We present a few examples of the JUNO ASC opportunity science here. As the Juno spacecraft approached the Earth-Moon system for the close encounter with the Earth on October 9, 2013, one of the ASC camera heads obtained imagery of the Earth-Moon system while the other three remained in full science (attitude determination) operation. This enabled the first movie of the Earth and Moon obtained by a spacecraft flying past the Earth in gravity assist. We also use the many artificial satellites in orbit about the Earth as calibration targets for the autonomous asteroid detection system inherent to the ASC autonomous star tracker. We shall also profile the zodiacal dust disk, using the interstellar image data, and present the outlook for small asteroid body detection and distribution being performed during Juno's passage from Earth flyby to Jovian orbit

  9. Miniature scientific-grade induction magnetometer for cubesats

    Science.gov (United States)

    Pronenko, Vira

    2017-04-01

    One of the main areas of space research is the study and forecasting of space weather. The society is more and more depending nowadays on satellite technology and communications, so it is vital to understand the physical process in the solar-terrestrial system which may disturb them. Besides the solar radiation and Space Weather effects, the Earth's ionosphere is also modified by the ever increasing industrial activity. There have been also multiple reports relating VLF and ELF wave activity to atmospheric storms and geological processes, such as earthquakes and volcanic activity. For advancing in these fields, the AC magnetic field permanent monitoring is crucial. Using the cubesat technology would allow increasing the number of measuring points dramatically. It is necessary to mention that the cubesats use for scientific research requires the miniaturization of scientific sensors what is a serious problem because the reduction of their dimensions leads, as a rule, to the parameters degradation, especially of sensitivity threshold. Today, there is no basic model of a sensitive miniature induction magnetometer. Even the smallest one of the known - for the Bepi-Colombo mission to Mercury - is too big for cubesats. The goal of the present report is to introduce the new design of miniature three-component sensor for measurement of alternative vector magnetic fields - induction magnetometer (IM). The study directions were concentrated on the ways and possibilities to create the miniature magnetometer with best combination of parameters. For this a set of scientific and technological problems, mostly aimed at the sensor construction improvement, was solved. The most important parameter characterizing magnetometer quality is its own magnetic noise level (NL). The analysis of the NL influencing factors is made and the ways to decrease it are discussed in the report. Finally, the LEMI-151 IM was developed for the SEAM cubesat mission with optimal performances within the

  10. Poly-SiGe-based MEMS Xylophone Bar Magnetometer

    OpenAIRE

    Rochus, Véronique; Jansen, R.; Tilmans, H. A. C.; Rottenberg, X.; Chen, C.; Ranvier, S.; Lamy, Hervé; Rochus, Pierre

    2012-01-01

    This paper presents the design, fabrication and preliminary characterization of highly sensitive MEMS-based Xylophone Bar Magnetometers (XBMs) realized in imec’s poly-SiGe MEMS technology. Key for our Lorentz force driven capacitively sensed resonant sensor are the combination of reasonably high Q-factor and conductivity of imec’s poly-SiGe, our optimized multiphysics sensor design targeting the maximization of the Q-factor in a wide temperature range as well as our proprietary monolithic abo...

  11. Three axis vector atomic magnetometer utilizing polarimetric technique

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, Swarupananda, E-mail: spradhan@barc.gov.in, E-mail: pradhans75@gmail.com [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400085, India and Homi Bhabha National Institute, Department of Atomic Energy, Mumbai 400094 (India)

    2016-09-15

    The three axis vector magnetic field measurement based on the interaction of a single elliptically polarized light beam with an atomic system is described. The magnetic field direction dependent atomic responses are extracted by the polarimetric detection in combination with laser frequency modulation and magnetic field modulation techniques. The magnetometer geometry offers additional critical requirements like compact size and large dynamic range for space application. Further, the three axis magnetic field is measured using only the reflected signal (one polarization component) from the polarimeter and thus can be easily expanded to make spatial array of detectors and/or high sensitivity field gradient measurement as required for biomedical application.

  12. Testing the three axis magnetometer and gradiometer MOURA and data comparison on San Pablo de los Montes Observatory.

    Science.gov (United States)

    Belen Fernandez, Ana; Sanz, Ruy; Covisa, Pablo; Tordesillas, Jose Manuel; Diaz-Michelena, Marina

    2013-04-01

    A magnetometer and gradiometer named MOURA has been developed with the objective to measure the magnetic field on Mars in the frame of Mars MetNet Precursor Mission (MMPM) [1]. MOURA is a compact, miniaturized, intelligent and low cost instrument, based on two sets of triaxial magnetometers separated one centimeter from each other to do gradiometry studies. It has a resolution of 2.2 nT, and a field range of + 65μT, which can be extended to +130 μT when sensors are saturated. [2] These sensor heads are Anisotropic MagnetoResistances (AMR) Commercial-Off-The-Shelf (COTS) by Honeywell, specifically HMC1043, which has been selected due to their relative low consumption, weight and size, factors very important for the mission with very limited mass and power budget (shared 150 g for three full payloads). Also, this technology has been previously successfully employed on board Unmanned Aerial Vehicles (UAV) to perform geomagnetic surveys in extreme conditions areas [3], and in several space missions for different applications. [4] After the development of the MOURA Engineering Qualification Model (EQM) in November 2011, an exhaustive set of tests have been performed to validate and fully characterize the instrument. Compensation equations have been derived for the temperature corrections in the operation range (between -135 °C and 30 °C) in controlled environments. These compensation equations have been applied to field data, which have shown to follow the daily Earth's magnetic field variations as registered by San Pablo Geomagnetic Observatory (IAGA code: SPT) (available at www.ign.es and www.intermagnet.org) with deviations lower than 40 nT. These deviations were attributed to several error factors as the different locations between MOURA and SPT and other possible different geomagnetic conditions. Due to the above, a measurement campaign on SPT installations are been done. The main objective is to compare MOURA measurements on a relevant environment, with data

  13. Saturation in nuclei

    CERN Document Server

    Lappi, T

    2010-01-01

    This talk discusses some recent studies of gluon saturation in nuclei. We stress the connection between the initial condition in heavy ion collisions and observables in deep inelastic scattering (DIS). The dominant degree of freedom in the small x nuclear wavefunction is a nonperturbatively strong classical gluon field, which determines the initial condition for the glasma fields in the initial stages of a heavy ion collision. A correlator of Wilson lines from the same classical fields, known as the dipole cross section, can be used to compute many inclusive and exclusive observables in DIS.

  14. Multi-flux-transformer MRI detection with an atomic magnetometer.

    Science.gov (United States)

    Savukov, Igor; Karaulanov, Todor

    2014-12-01

    Recently, anatomical ultra-low field (ULF) MRI has been demonstrated with an atomic magnetometer (AM). A flux-transformer (FT) has been used for decoupling MRI fields and gradients to avoid their negative effects on AM performance. The field of view (FOV) was limited because of the need to compromise between the size of the FT input coil and MRI sensitivity per voxel. Multi-channel acquisition is a well-known solution to increase FOV without significantly reducing sensitivity. In this paper, we demonstrate twofold FOV increase with the use of three FT input coils. We also show that it is possible to use a single atomic magnetometer and single acquisition channel to acquire three independent MRI signals by applying a frequency-encoding gradient along the direction of the detection array span. The approach can be generalized to more channels and can be critical for imaging applications of non-cryogenic ULF MRI where FOV needs to be large, including head, hand, spine, and whole-body imaging. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Effect of mobility devices on orientation sensors that contain magnetometers.

    Science.gov (United States)

    Kendell, Cynthia; Lemaire, Edward D

    2009-01-01

    Orientation sensors containing magnetometers use the earth's magnetic field as a reference. Ferromagnetic objects may distort this magnetic field, leading to inaccurate orientation output. We explored the viability of these orientation sensors for motion analysis in an assistive mobility device rehabilitative setting. We attached two MTx orientation sensors (XSens; Enschade, the Netherlands), connected to the XBus Master data collection unit (XSens), to a plastic frame such that the relative angle between sensors was constant. We then moved a series of mobility devices in proximity to the plastic frame: two knee-ankle-foot orthoses (aluminum, stainless steel), one ankle-foot orthosis, two transtibial prostheses (exoskeletal, endoskeletal), two walkers (standard, Challenger Low Wide [Evolution Technologies; Port Coquitlam, Canada]), and two wheelchairs (Tango [OrthoFab; Quebec City, Canada], GTi [Quickie; Phoenix, Arizona]). For each mobility device, we calculated the average difference in relative angle between the baseline and peak angles for each of five trials. Errors ranged from less than 0.10 to 35.29 degrees, depending on the mobility device and frame positioning near the device. This demonstrated the large errors that can occur when magnetometer-based orientation sensors with mobility devices are used. While strategic orientation sensor placement on some mobility devices can minimize these errors to an acceptable level, testing protocols should be implemented to verify orientation sensor accuracy for these applications.

  16. Development of autonomous magnetometer rotorcraft for wide area assessment

    Energy Technology Data Exchange (ETDEWEB)

    Roelof Versteeg; Matt Anderson; Les Beard; Eric Corban; Darryl Curley; Jeff Gamey; Ross Johnson; Dwight Junkin; Mark McKay; Jared Salzmann; Mikhail Tchernychev; Suraj Unnikrishnan; Scott Vinson

    2010-04-01

    Large areas across the United States are potentially contaminated with UXO, with some ranges encompassing tens to hundreds of thousands of acres. Technologies are needed which will allow for cost effective wide area scanning with 1) near 100 % coverage and 2) near 100 % detection of subsurface ordnance or features indicative of subsurface ordnance. The current approach to wide area assessment is a multi-level one, in which medium - altitude fixed wing optical imaging is used for an initial site assessment. This assessment is followed with low altitude manned helicopter based magnetometry. Subsequent to this wide area assessment targeted surface investigations are performed using either towed geophysical sensor arrays or man portable sensors. In order to be an effective tool for small UXO detection, the sensing altitude for magnetic site investigations needs to be on the order of 1 – 3 meters. These altitude requirements mean that manned helicopter surveys will generally only be feasible in large, open and relatively flat terrains. While such surveys are effective in mapping large areas relatively fast there are substantial mobilization/demobilization, staffing and equipment costs associated with these surveys (resulting in costs of approximately $100-$150/acre). In addition, due to the low altitude there are substantial risks to pilots and equipment. Surface towed arrays provide high resolution maps but have other limitations, e.g. in their ability to navigate rough terrain effectively. There is thus a need for other systems which can be used for effective data collection. An UAV (Unmanned Aerial Vehicle) magnetometer platform is an obvious alternative. The motivation behind such a system is that it reduces risk to operators, is lower in initial and Operational and Maintenance (O&M) costs (and can thus potentially be applied to smaller sites) and has the potential of being more effective in terms of detection and possibly characterization (through the use of

  17. Structure and magnetic properties of irradiated Fe/Fe oxide core-shell nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    McCloy, John S.; Jiang, Weilin; Sundararajan, Jennifer A.; Qiang, You; Burks, Edward; Liu, Kai

    2013-04-25

    A cluster deposition method was used to produce a film of loosely aggregated particles of Fe-Fe3O4 core-shell nanoclusters with an 8 nm iron core size and 2 nm oxide shell thickness. The film of particles on a silicon substrate was irradiated with 5.5 MeV Si2+ ions to a fluence of 1016 cm-2 near room temperature, and computer simulations based on the SRIM (Stopping and Range of Ions in Matter) code show that the implanted Si species stops near the film-substrate interface. The ion irradiation creates a structural change in the film with corresponding chemical and magnetic changes. X-ray diffraction shows that the core size and chemistry stay the same but the shell becomes FeO that grows to a thickness of 17 nm. Helium ion microscopy shows that the previously separate particles have densified into a nearly continuous film. Major loop magnetic hysteresis measurements show a decrease in saturation magnetization that we attribute to the presence of the antiferromagnetic (AFM) FeO shell. First-order reversal curve measurements on the irradiated film performed with a vibrating sample magnetometer show that the AFM shell prevents the particles from interacting magnetically, leading to low coercivity from the iron core and little bias field from the core interactions. These results, and others reported previously on different compositions (Fe3O4 or FeO+Fe3N nanoclusters), show that the ion irradiation behavior of nanocluster films such as these depends strongly on the initial nanostructure and chemistry.

  18. Dynamics of saturated energy condensation in two-dimensional turbulence.

    Science.gov (United States)

    Chan, Chi-kwan; Mitra, Dhrubaditya; Brandenburg, Axel

    2012-03-01

    In two-dimensional forced Navier-Stokes turbulence, energy cascades to the largest scales in the system to form a pair of coherent vortices known as the Bose condensate. We show, both numerically and analytically, that the energy condensation saturates and the system reaches a statistically stationary state. The time scale of saturation is inversely proportional to the viscosity and the saturation energy level is determined by both the viscosity and the force. We further show that, without sufficient resolution to resolve the small-scale enstrophy spectrum, numerical simulations can give a spurious result for the saturation energy level. We also find that the movement of the condensate is similar to the motion of an inertial particle with an effective drag force. Furthermore, we show that the profile of the saturated coherent vortices can be described by a Gaussian core with exponential wings.

  19. Synthesis of superparamagnetic bare Fe₃O₄ nanostructures and core/shell (Fe₃O₄/alginate) nanocomposites.

    Science.gov (United States)

    Srivastava, Manish; Singh, Jay; Yashpal, Madhu; Gupta, Dinesh Kumar; Mishra, R K; Tripathi, Shipra; Ojha, Animesh K

    2012-07-01

    In this article we report about the synthesis of superparamagnetic bare Fe3O4 nanostructures and core/shell (Fe3O4/alginate) nanocomposites by simple low-temperature based method at pH values 5, 9, and 14. The structural morphology and magnetic behavior of Fe3O4 nanostructures and core/shell (Fe3O4/alginate) nanocomposites (Fe3O4/alg NCs) have been investigated by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (RS), ultraviolet-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and vibrating sample magnetometer (VSM). The particle size was calculated by TEM measurements and it turns out to be ∼10 nm and ∼14 nm for bare Fe3O4 nanoparticle and Fe3O4/alg NCs with core/shell structure, respectively. The magnetic properties of the synthesized products were found to be function of pH at which the synthesis has been done. The synthesized Fe3O4 nanoparticle and Fe3O4/alg NCs were found to be superparmagnetic in nature at room temperature. We observed that the value of saturation magnetization in case of Fe3O4/alg NCs decreases by increasing the pH value. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Development, construction and analysis of the "Ørsted" fluxgate magnetometer

    DEFF Research Database (Denmark)

    Nielsen, Otto V; Petersen, Jan Raagaard; Primdahl, Fritz

    1995-01-01

    The experiments and theoretical considerations leading to the construction of a high-performance three-axis fluxgate magnetometer are described. The magnetometer will be used (1996) in the Earth's field mapping satellite named "Ørsted". The fluxgate sensors are based on stress-annealed metallic g...

  1. Preliminary Report: DESiGN and Test Result of KSR-3 Rocket Magnetometers

    Directory of Open Access Journals (Sweden)

    Hyo-Min Kim

    2000-12-01

    Full Text Available The solar wind contributes to the formation of unique space environment called the Earth's magnetosphere by various interactions with the Earth's magnetic field. Thus the solar-terrestrial environment affects the Earth's magnetic field, which can be observed with an instrument for the magnetic field measurement, the magnetometer usually mounted on the rocket and the satellite and based on the ground observatory. The magnetometer is a useful instrument for the spacecraft attitude control as well as the Earth's magnetic field measurements for a scientific purpose. In this paper, we present the preliminary design and test results of the two onboard magnetometers of KARI's (Korea Aerospace Research Institute sounding rocket, KSR-3, which will be launched four times during the period of 2001-02. The KSR-3 magnetometers consist of the fluxgate magnetometer, MAG/AIM (Attitude Information Magnetometer for acquiring the rocket flight attitude information, and of the search-coil magnetometer, MAG/SIM (Scientific Investigation Magnetometer for the observation of the Earth's magnetic field fluctuations. With the MAG/AIM, the 3-axis attitude information can be acquired by the comparison of the resulting dc magnetic vector field with the IGRF (International Geomagnetic Reference Field. The Earth's magnetic field fluctuations ranging from 10 to 1,000 Hz can also be observed with the MAG/SIM measurement.

  2. Correlation between fluxgate and SQUID magnetometer data sets for geomagnetic storms

    Directory of Open Access Journals (Sweden)

    Matladi Thabang

    2014-01-01

    Full Text Available There has always been a need to monitor the near Earth's magnetic field, as this monitoring provides understanding and possible predictions of Space Weather events such as geomagnetic storms. Conventional magnetometers such as fluxgates have been used for decades for Space Weather research. The use of highly sensitive magnetometers such as Superconducting QUantum Interference Devices (SQUIDs, promise to give more insight into Space Weather. SQUIDs are relatively recent types of magnetometers that exploit the superconductive effects of flux quantization and Josephson tunneling to measure magnetic flux. SQUIDs have a very broad bandwidth compared to most conventional magnetometers and can measure magnetic flux as low as a few femtotesla. Since SQUIDs have never been used in Space Weather research, unshielded, it is necessary to investigate if they can be reliable Space Weather instruments. The validation is performed by comparing the frequency content of the SQUID and fluxgate magnetometers, as reported by Phiri.

  3. Saturated Zone Colloid Transport

    Energy Technology Data Exchange (ETDEWEB)

    H. S. Viswanathan

    2004-10-07

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, R{sub col} is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of R{sub col} that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, k{sub att}, and detachment rate constants, k{sub det}, of colloids to the fracture surface have been measured for the fractured volcanics, and separate R{sub col} uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant

  4. Magnetometer-augmented IMU simulator: in-depth elaboration.

    Science.gov (United States)

    Brunner, Thomas; Lauffenburger, Jean-Philippe; Changey, Sébastien; Basset, Michel

    2015-03-04

    The location of objects is a growing research topic due, for instance, to the expansion of civil drones or intelligent vehicles. This expansion was made possible through the development of microelectromechanical systems (MEMS), inexpensive and miniaturized inertial sensors. In this context, this article describes the development of a new simulator which generates sensor measurements, giving a specific input trajectory. This will allow the comparison of pose estimation algorithms. To develop this simulator, the measurement equations of every type of sensor have to be analytically determined. To achieve this objective, classical kinematic equations are used for the more common sensors, i.e., accelerometers and rate gyroscopes. As nowadays, the MEMS inertial measurement units (IMUs) are generally magnetometer-augmented, an absolute world magnetic model is implemented. After the determination of the perfect measurement (through the error-free sensor models), realistic error models are developed to simulate real IMU behavior. Finally, the developed simulator is subjected to different validation tests.

  5. Associating ground magnetometer observations with current or voltage generators

    DEFF Research Database (Denmark)

    Hartinger, M. D.; Xu, Z.; Clauer, C. R.

    2017-01-01

    A circuit analogy for magnetosphere-ionosphere current systems has two extremes for driversof ionospheric currents: ionospheric elec tric fields/voltages constant while current/conductivity vary—the“voltage generator”—and current constant while electric field/conductivity vary—the “current generator.......”Statistical studies of ground magnetometer observations associated with dayside Transient High LatitudeCurrent Systems (THLCS) driven by similar mechanisms find contradictory results using this paradigm:some studies associate THLCS with voltage generators, others with current generators. We argue that mostof...... these two assumptions substantially alter expectations for magnetic perturbations associatedwith either a current or a voltage generator. Our results demonstrate that before interpreting groundmagnetometer observations of THLCS in the context of current/voltage generators, the location...

  6. Magnetometer-Augmented IMU Simulator: In-Depth Elaboration

    Directory of Open Access Journals (Sweden)

    Thomas Brunner

    2015-03-01

    Full Text Available The location of objects is a growing research topic due, for instance, to the expansion of civil drones or intelligent vehicles. This expansion was made possible through the development of microelectromechanical systems (MEMS, inexpensive and miniaturized inertial sensors. In this context, this article describes the development of a new simulator which generates sensor measurements, giving a specific input trajectory. This will allow the comparison of pose estimation algorithms. To develop this simulator, the measurement equations of every type of sensor have to be analytically determined. To achieve this objective, classical kinematic equations are used for the more common sensors, i.e., accelerometers and rate gyroscopes. As nowadays, the MEMS inertial measurement units (IMUs are generally magnetometer-augmented, an absolute world magnetic model is implemented. After the determination of the perfect measurement (through the error-free sensor models, realistic error models are developed to simulate real IMU behavior. Finally, the developed simulator is subjected to different validation tests.

  7. Benchtop time-resolved magneto-optical Kerr magnetometer.

    Science.gov (United States)

    Barman, Anjan; Kimura, T; Otani, Y; Fukuma, Y; Akahane, K; Meguro, S

    2008-12-01

    We present here the construction and application of a compact benchtop time-resolved Kerr magnetometer to measure the magnetization precession in magnetic thin films and lithographically patterned elements. As opposed to very expensive femtosecond lasers this system is built upon a picosecond pulsed injection diode laser and electronic pulse and delay generators. The precession is triggered by the electronic pulses of controlled duration and shape, which is launched onto the sample by a microstrip line. We used polarized optical pulses synchronous to the electronic pulses to measure the magneto-optical Kerr rotation. The system is integrated in a conventional upright microscope configuration with separate illumination, imaging, and magneto-optical probe paths. The system offers high stability, relative ease of alignment, sample changing, and a long range of time delay. We demonstrate the measurements of time-resolved dynamics of a Permalloy microwire and microdot using this system, which showed dynamics at two different time scales.

  8. The Search-coil Magnetometer for the THOR mission

    Science.gov (United States)

    Sahraoui, Fouad; Jannet, Guillaume; Pinçon, Jean-louis; Mansour, Malik; Chalumeau, Gilles; Chabassière, Michel; Hachemi, Tedjani; Jeandet, Alexis; Henri, Pierre; Le Contel, Olivier; Rezeau, Laurence

    2017-04-01

    Turbulence Heating ObserveR (THOR) is the first mission ever flown in space that is fully dedicated to plasma turbulence. The search-coil magnetometer (SCM) of THOR is a triaxial dual-band antenna dedicated to measuring the magnetic field fluctuations in the frequency range [1Hz,4kHz] and [1,200]kHz. THOR/SCM has a long heritage from earlier space missions such as Cluster, Themis, MMS, BepiColombo, Taranis, Solar orbiter and Solar Probe. In comparison to those missions, the SCM of THOR has a higher sensitivity level, which makes it capable of measuring very low amplitude magnetic fluctuations, in particular in the solar wind. Those measurements are crucial to address the problem of turbulence and energy dissipation at electron scales, a central goal of the THOR mission.

  9. Measuring miniature eye movements by means of a SQUID magnetometer

    Science.gov (United States)

    Peters, M. J.; Dunajski, Z.; Meijzssen, T. E. M.; Breukink, E. W.; Wevers-Henke, J. J.

    A new technique to measure small eye movements is reported. The precise recording of human eye movements is necessary for research on visual fatigue induced by visual display units. 1 So far all methods used have disadvantages: especially those which are sensitive or are rather painful. 2,3 Our method is based on a transformation of mechanical vibrations into magnetic flux variations. In order to do this a small magnet is embedded in a close-fitting soft contact lens. The magnetic flux variations caused by eyeball movements during fixation are measured by means of a SQUID magnetometer. The recordings show the typical fixation pattern of a human eye. This pattern is composed of three kinds of movements: saccades, drift and microtremor. The last-mentioned type of movements are displacements in the order of 2 μm. It is possible to distinguish between movements which are perpendicular to each other.

  10. First Results of the Juno Magnetometer Investigation in Jupiter's Magnetosphere

    Science.gov (United States)

    Connerney, Jack; Oliversen, Ronald; Espley, Jared; Kotsiaros, Stavros; Joergensen, John; Joergensen, Peter; Merano, Jose; Denver, Troelz; Benn, Mathias; Bloxham, Jeremy; Bolton, Scott; Levin, Steve

    2017-04-01

    The Juno spacecraft entered polar orbit about Jupiter on July 4, 2016, after a Jupiter Orbit Insertion (JOI) main engine burn lasting 35 minutes. Juno's science instruments were not powered during the critical maneuver sequence ( 5 days) but were fully operational shortly afterward. The 53.5-day capture orbit provides Juno's science instruments with the opportunity to sample the Jovian environment close up (to 1.06 Jovian radii, Rj) and in polar orbit extending to the outer reaches of the Jovian magnetosphere. Jupiter's gravity and magnetic fields will be globally mapped with unprecedented accuracy as Juno conducts a study of Jupiter's interior structure and composition, as well as the first comprehensive exploration of the polar magnetosphere. The magnetic field investigation onboard Juno is equipped with two magnetometer sensor suites, located at 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads which provide accurate attitude determination for the FGM sensors. The first few periapsis passes available to date revealed an extraordinary spatial variation of the magnetic field close to the planet's surface, suggesting that Juno may be sampling the field closer to the dynamo region than widely anticipated, i.e., portending a dynamo surface extending to relatively large radial distance ( 0.9Rj?). We present the first observations of Jupiter's magnetic field obtained in close proximity to the planet, and speculate on what wonders await as more longitudes are drawn across the global map (32 polar orbits separated by <12° longitude) that the Juno mission was designed to acquire.

  11. SATURATED-SUBCOOLED STRATIFIED FLOW IN HORIZONTAL PIPES

    Energy Technology Data Exchange (ETDEWEB)

    Richard Schultz

    2010-08-01

    Advanced light water reactor systems are designed to use passive emergency core cooling systems with horizontal pipes that provide highly subcooled water from water storage tanks or passive heat exchangers to the reactor vessel core under accident conditions. Because passive systems are driven by density gradients, the horizontal pipes often do not flow full and thus have a free surface that is exposed to saturated steam and stratified flow is present.

  12. Brine Distribution after Vacuum Saturation

    DEFF Research Database (Denmark)

    Hedegaard, Kathrine; Andersen, Bertel Lohmann

    1999-01-01

    Experiments with the vacuum saturation method for brine in plugs of chalk showed that a homogeneous distribution of brine cannot be ensured at saturations below 20% volume. Instead of a homogeneous volume distribution the brine becomes concentrated close to the surfaces of the plugs...

  13. Misconceptions in Reporting Oxygen Saturation

    NARCIS (Netherlands)

    Toffaletti, John; Zijlstra, Willem G.

    2007-01-01

    BACKGROUND: We describe some misconceptions that have become common practice in reporting blood gas and cooximetry results. In 1980, oxygen saturation was incorrectly redefined in a report of a new instrument for analysis of hemoglobin (Hb) derivatives. Oxygen saturation (sO(2)) was redefined as the

  14. Upscaling soil saturated hydraulic conductivity from pore throat characteristics

    Science.gov (United States)

    Upscaling and/or estimating saturated hydraulic conductivity Ksat at the core scale from microscopic/macroscopic soil characteristics has been actively under investigation in the hydrology and soil physics communities for several decades. Numerous models have beendeveloped based on different approac...

  15. Nuclear Magnetic Resonance and Elastic Wave Velocity of Chalk Saturated with Brines Containing Divalent Ions

    DEFF Research Database (Denmark)

    Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    divided into groups of three and each group was saturated either with deionized water, calcite equilibrated water, or sodium chloride, magnesium chloride and calcium chloride solutions of the same ionic strength. Saturation with solutions that contain divalent ions caused major shifts in the distribution...... of the relaxation time. Core samples saturated with calcium chloride solution relaxed slower and those saturated with magnesium chloride solution relaxed faster than the rest of the samples. Along with the changes in relaxation the samples experienced smaller velocities of elastic waves when saturated with MgCl2...

  16. Saturated Zone In-Situ Testing

    Energy Technology Data Exchange (ETDEWEB)

    P. W. Reimus; M. J. Umari

    2003-12-23

    colloid transport parameters. (4) Comparisons of sorption parameter estimates for a reactive solute tracer (lithium ion) derived from both the C-wells field tracer tests and laboratory tests using C-wells core samples. (5) Sorption parameter estimates for lithium ion derived from laboratory tests using alluvium samples from NC-EWDP-19D1 (one of the wells at the ATC) so that a comparison of laboratory- and field-derived sorption parameters can be made in saturated alluvium if cross-hole tracer tests are conducted at the ATC.

  17. IceBridge Flux Gate Magnetometer L0 Raw Magnetic Field

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Flux Gate Magnetometer L0 Raw Magnetic Field (IMFGM0) data set contains magnetic field readings taken over Antarctica using the Integrity...

  18. In-orbit calibration of the lunar magnetometer onboard SELENE (KAGUYA)

    National Research Council Canada - National Science Library

    Takahashi, Futoshi; Shimizu, Hisayoshi; Matsushima, Masaki; Shibuya, Hidetoshi; Matsuoka, Ayako; Nakazawa, Satoru; Iijima, Yuichi; Otake, Hisashi; Tsunakawa, Hideo

    2009-01-01

    The high-sensitivity fluxgate Lunar MAGnetometer (LMAG) is mounted on SELENE (KAGUYA) to investigate the near-surface electromagnetic environment and the evolution of the Moon through magnetic field observation...

  19. Quantum assisted enhancement of optical magnetometer with squeezed vacuum in hot Rb vapor

    Science.gov (United States)

    Mikhailov, Eugeniy; Horrom, Travis; Singh, Robinjeet

    2012-06-01

    We demonstrate enhancement to the sensitivity of an optical magnetometer based on the nonlinear magneto-optical Faraday effect in ^87Rb vapor with the use of squeezed vacuum. We generate quantum squeezed vacuum states via the polarization self-rotation effect in hot ^87Rb vapor exhibiting noise spectrum suppression ranging from frequencies of a few hundred Hz to several MHz. Injection of such squeezed states into a magneto-optical magnetometer provides broad band noise suppression of close to 2 dB. We study various parameters of the magnetometer such as Rb cell temperature, pump power, and the noise spectrum of the probe signal to identify the most favorable conditions for quantum enhanced magnetometry. Our experimental arrangement offers potential quantum improvement to the most sensitive magnetometers at frequencies down to hundreds of Hz, which can be useful for biological, geophysical, medical, or military sensing applications.

  20. IceBridge Scintrex CS-3 Cesium Magnetometer L0 Raw Magnetic Field

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Scintrex CS-3 Cesium Magnetometer L0 Raw Magnetic Field data set contains magnetic field readings and fluxgate values taken over Greenland using...

  1. IceBridge Geometrics 823A Cesium Magnetometer L0 Raw Magnetic Field

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Geometrics 823A Cesium Magnetometer L0 Raw Magnetic Field (IMGEO0) data set contains magnetic field readings taken over Antarctica using the...

  2. IceBridge Flux Gate Magnetometer L0 Raw Magnetic Field, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Flux Gate Magnetometer L0 Raw Magnetic Field (IMFGM0) data set contains magnetic field readings taken over Antarctica using the Integrity...

  3. IceBridge Geometrics 823A Cesium Magnetometer L0 Raw Magnetic Field, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Geometrics 823A Cesium Magnetometer L0 Raw Magnetic Field (IMGEO0) data set contains magnetic field readings taken over Antarctica using the...

  4. IceBridge Geometrics 823A Cesium Magnetometer L2 Geolocated Magnetic Anomalies, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Geometrics 823A Cesium Magnetometer L2 Geolocated Magnetic Anomalies (IMGEO2) data set contains magnetic anomaly measurements taken over...

  5. Improving Sensitivity and Bandwidth of an Atomic Magnetometer using Quantum Non-Demolition Measurement

    Science.gov (United States)

    Shah, Vishal; Vasilakis, Georgios; Romalis, Michael

    2009-05-01

    The fundamental sensitivity of an atomic magnetometer is limited by spin projection noise. In the case of uniform spin relaxation, it is well understood that it is not possible to improve the sensitivity using spin squeezing induced by quantum non-demolition (QND) measurement for measurement time scales longer than spin relaxation time [1, 2]. It is however possible to increase the bandwidth of the magnetometer using QND measurement. Here we experimentally demonstrate, in excellent agreement with the theory, an improvement in the bandwidth of our scalar alkali vapor atomic magnetometer using continuous QND measurement. We also investigate the possibility of improving sensitivity of our magnetometer in the special case in which the spin relaxation is time dependent. The case of time dependent spin relaxation naturally arises in high polarization regime in an alkali-alkali spin-exchange relaxation dominated atomic sample. [1] S. F. Huelga, Phys. Rev. Lett. 79, 3865 -- 3868, 1997. [2] M. Auzinsh, Phys. Rev. Lett. 93, 173002, 2004.

  6. A rubidium Mx-magnetometer for measurements on solid state spins

    Science.gov (United States)

    Arnold, Daniel; Siegel, Steven; Grisanti, Emily; Wrachtrup, Jörg; Gerhardt, Ilja

    2017-02-01

    The detection of environmental magnetic fields is well established by optically pumped atomic magnetometers. Another focus of magnetometry can be the research on magnetic or spin-active solid-state samples. Here we introduce a simple and compact design of a rubidium-based Mx magnetometer, which allows for hosting solid-state samples. The optical, mechanical, and electrical design is reported, as well as simple measurements which introduce the ground-state spin-relaxation time, the signal-to-noise ratio of a measurement, and subsequently the overall sensitivity of the magnetometer. The magnetometer is optimized for the most sensitive operation with respect to laser power and magnetic field excitation at the Larmor frequency.

  7. A rubidium Mx-magnetometer for measurements on solid state spins.

    Science.gov (United States)

    Arnold, Daniel; Siegel, Steven; Grisanti, Emily; Wrachtrup, Jörg; Gerhardt, Ilja

    2017-02-01

    The detection of environmental magnetic fields is well established by optically pumped atomic magnetometers. Another focus of magnetometry can be the research on magnetic or spin-active solid-state samples. Here we introduce a simple and compact design of a rubidium-based Mx magnetometer, which allows for hosting solid-state samples. The optical, mechanical, and electrical design is reported, as well as simple measurements which introduce the ground-state spin-relaxation time, the signal-to-noise ratio of a measurement, and subsequently the overall sensitivity of the magnetometer. The magnetometer is optimized for the most sensitive operation with respect to laser power and magnetic field excitation at the Larmor frequency.

  8. IceBridge Geometrics 823A Cesium Magnetometer L2 Geolocated Magnetic Anomalies

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Geometrics 823A Cesium Magnetometer L2 Geolocated Magnetic Anomalies (IMGEO2) data set contains magnetic anomaly measurements taken over...

  9. Rad-Hard Sigma-Delta 3-channel ADC for Fluxgate Magnetometers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed project aims to develop a multi-channel analog to digital converter (ADC) required for a fluxgate magnetometer (EPD) employed on NASA's planetary...

  10. Magnetic property characterization of magnetite (Fe3O4) nanorod cores for integrated solenoid rf inductors

    Science.gov (United States)

    Kim, Jinsook; Ni, Weiping; Lee, Chungho; Kan, Edwin C.; Hosein, Ian D.; Song, Yanning; Liddell, Chekesha

    2006-04-01

    The on-chip magnetic solenoid inductors with Fe3O4 magnetite nanorod (MN) cores are fabricated and characterized up to 40 GHz. By vibrating-sample magnetometer measurements, the magnetic property of MN as a magnetic core for a solenoid inductor is investigated. In addition, high-frequency characterization with scattering parameter measurements is performed to estimate the high-frequency performance of the solenoid inductors with the MN cores.

  11. Integration of a MEMS Inertial Measuring Unit with a MEMS Magnetometer for 3D Orientation Estimation

    DEFF Research Database (Denmark)

    Cai, Junping; Malureanu, Christian; Andersen, Niels Lervad

    2011-01-01

    This paper presents an algorithm for combining the measurements of a MEMS Inertial Measurement Unit (IMU) and a MEMS magnetometer. The measurements are done using a special designed and customized miniature detecting system for 3D orientation estimation, and position tracking......This paper presents an algorithm for combining the measurements of a MEMS Inertial Measurement Unit (IMU) and a MEMS magnetometer. The measurements are done using a special designed and customized miniature detecting system for 3D orientation estimation, and position tracking...

  12. Identification of a dynamic atmosphere at Enceladus with the Cassini magnetometer.

    Science.gov (United States)

    Dougherty, M K; Khurana, K K; Neubauer, F M; Russell, C T; Saur, J; Leisner, J S; Burton, M E

    2006-03-10

    The Cassini magnetometer has detected the interaction of the magnetospheric plasma of Saturn with an atmospheric plume at the icy moon Enceladus. This unanticipated finding, made on a distant flyby, was subsequently confirmed during two follow-on flybys, one very close to Enceladus. The magnetometer data are consistent with local outgassing activity via a plume from the surface of the moon near its south pole, as confirmed by other Cassini instruments.

  13. Calibrating the Swarm: Networked Small Satellite Magnetometers for Auroral Plasma Science

    OpenAIRE

    Parham, Jonathan; Van Dessel, Osi; Kromis, Maria; Teng, Phillip; Semeter, Joshua; Zosuls, Alexks; Walsh, Brian

    2017-01-01

    Motivated by small-scale auroral plasma science, ANDESITE, a 6U CubeSat with eight deployable picosatellites, will fly a network of magnetometers through the Northern Lights. With the spacecraft due to launch on the upcoming ELaNa XIX mission, this work details its science mission architecture along with the payload design and calibration. Each three-axis magnetometer instrument is hosted by a deployable picosatellite about the size of a piece of toast. Calibration of these sensors included a...

  14. The MAGIC of CINEMA: First in-flight science results from a miniaturised anisotropic magnetoresistive magnetometer

    OpenAIRE

    M. O. Archer; Horbury, T. S.; Brown, P; Eastwood, J. P.; Oddy, T. M.; B. J. Whiteside; Sample, J. G.

    2015-01-01

    We present the first in-flight results from a novel miniaturised anisotropic magnetoresistive space magnetometer, MAGIC (MAGnetometer from Imperial College), aboard the first CINEMA (CubeSat for Ions, Neutrals, Electrons and MAgnetic fields) spacecraft in low Earth orbit. An attitude-independent calibration technique is detailed using the International Geomagnetic Reference Field (IGRF), which is temperature dependent in the case of the outboard sensor. We show that the sens...

  15. Design & simulation of in-plane MEMS Lorentz force magnetometer

    Science.gov (United States)

    Jyoti, Aditi, Tripathi, C. C.; Gopal, Ram

    2016-03-01

    This report presents the design and simulation of a MEMS based In-plane Lorentz Force Magnetometer (I-LFM), simulated for 8 um UV-LIGA technology using FEM tool of COMSOL Multiphysics 4.3b. Designed I-LFM was simulated in the magnetic field range varied from 1 μJT to 100μJT. The proposed structure composed of a comb drive actuator, configured such that the fingers overlap with each other to generate capacitive coupling for its actuation. The magnetic field can be detected in Z-axis by this comb drive structure. The device was excited by supplying the sinusoidal current with the frequency equivalent to resonance frequency of the device at its first mode i.e. 12.047 kHz. In order to achieve the maximum mechanical output, the device was operated at the resonant frequency. Simulations based results shows a good linearity in the magnetic field range of 1 μJT to 100 μJT with a high quality factor of 130.

  16. Ground pulsation magnetometer observations conjugated with relativistic electron precipitation

    Science.gov (United States)

    Yahnin, A. G.; Yahnina, T. A.; Raita, T.; Manninen, J.

    2017-09-01

    In this report, we investigate the role of electromagnetic ion cyclotron (EMIC) waves in production of relativistic electron precipitation (REP). Over a thousand REP events were detected from four NOAA Polar-orbiting Operational Environmental Satellites in July-December 2005. Of these, a total of 112 events were conjugated with a ground-based network of six Finnish induction coil magnetometers and one in Lovozero observatory at Kola Peninsula, Russia. The observation of geomagnetic pulsations during the conjugated events showed that about one third of them were accompanied by pulsations in the Pc1 range, which are the signature of EMIC waves. In fact, the sources of some of these EMIC waves were well outside the location of the REP event. This means that in such cases the REP events were not originated from scattering by EMIC waves. Finally, it is concluded that for this limited set of conjugated events only a quarter might be related to scattering by EMIC waves. The majority of the events are not correlated with EMIC wave signatures in ground-based observations; they were associated with either no pulsations or noise-like pulsations PiB and PiC.

  17. Ultra-sensitive Magnetic Microscopy with an Optically Pumped Magnetometer

    Science.gov (United States)

    Kim, Young Jin; Savukov, Igor

    2016-04-01

    Optically pumped magnetometers (OPMs) based on lasers and alkali-metal vapor cells are currently the most sensitive non-cryogenic magnetic field sensors. Many applications in neuroscience and other fields require high-resolution, high-sensitivity magnetic microscopic measurements. In order to meet this demand we combined a cm-size spin-exchange relaxation-free (SERF) OPM and flux guides (FGs) to realize an ultra-sensitive FG-OPM magnetic microscope. The FGs serve to transmit the target magnetic flux to the OPM thus improving both the resolution and sensitivity to small magnetic objects. We investigated the performance of the FG-OPM device using experimental and numerical methods, and demonstrated that an optimized device can achieve a unique combination of high resolution (80 μm) and high sensitivity (8.1 pT/). In addition, we also performed numerical calculations of the magnetic field distribution in the FGs to estimate the magnetic noise originating from the domain fluctuations in the material of the FGs. We anticipate many applications of the FG-OPM device such as the detection of micro-biological magnetic fields; the detection of magnetic nano-particles; and non-destructive testing. From our theoretical estimate, an FG-OPM could detect the magnetic field of a single neuron, which would be an important milestone in neuroscience.

  18. Preparation of nanofiber polythiophene layered on Ba x Sr1- x Fe12O19/Fe3O4/polyacrylic acid core-shell structure and its microwave absorption investigation

    Science.gov (United States)

    Hosseini, Seyed Hossein; Moloudi, Maryam

    2015-09-01

    Ba x Sr1- x Fe12O19/Fe3O4/polyacrylic acid/polythiophene (Ba x Sr1- x Fe12O19/Fe3O4/PAA/PTh) nanocomposites with multi-core-shell structure were successfully synthesized by four steps. The samples were characterized by FTIR, X-ray diffraction (XRD), transmission electron microscope (TEM), vibrating sample magnetometer, and radar absorbing material reflectivity far-field radar cross-section method, respectively. XRD and TEM results indicated that the obtained nanoparticles have multi-core-shell morphology. The magnetic properties and microwave absorption analyses reveal that there are interphase interactions at the interface of Ba x Sr1- x Fe12O19, Fe3O4, PAA, and PTh, which can affect the magnetic properties and microwave absorption properties of the samples. The microwave-absorbing properties of nanocomposites were investigated at 8-14 GHz. A typical layer absorber exhibited an excellent microwave absorption with a -26 dB maximum absorption at 14 GHz. Compared with core material, the coercivity and saturation magnetization of multi-core-shell nanocomposites decrease obviously, but the microwave absorption properties of nanocomposites are improved greatly. The results show that these composite could be used as advancing absorption and shielding materials due to their favorable microwave-absorbing properties.

  19. Co-seismic signatures in magnetometer, geophone, and infrasound data during the Meinong Earthquake

    Directory of Open Access Journals (Sweden)

    Jann-Yenq Liu

    2017-01-01

    Full Text Available This paper utilizes 10 stations of co-located seismometer, QuakeFinder/infrasound to observe co-seismic signatures triggered by the 6 February 2016 M 6.6 Meinong Earthquake. Each QuakeFinder system consists of a 3-axes induction magnetometer, an air conductivity sensor, a geophone, and temperature/relative humidity sensors. There are no obvious charges in the positive/negative ions, the temperature, and the humidity, while the magnetometer, the geophone, and infrasound data detect clear co-seismic signatures, similar to seismic waves recorded by seismometers. The magnetometers register high-frequency pulsations, like seismic waves, and superimpose with low-frequency variations, which could be caused by the magnetometer shaking/tilting and/or the underground water level change, respectively, upon the arrival of seismic waves. The spectrum centering around 2.0 Hz of the co-seismic geophone fluctuations is similar to that of the seismic waves. However, the energy of co-seismic geophone fluctuations (also magnetometer pulsations yields an exponential decay to the distance of a station to the epicenter, while the energy of the seismic waves is inversely proportional to the square of the distance. This suggests that the mechanisms for detecting seismic waves of the QuakeFinder system and seismometers are different. In general, the geophone and magnetometer/infrasound system are useful to record high- and low-frequency seismic waves, respectively.

  20. The low cost Proton Precession Magnetometer developed at the Indian Institute of Geomagnetism

    Science.gov (United States)

    Mahavarkar, P.; Singh, S.; Labde, S.; Dongre, V.; Patil, A.

    2017-05-01

    Proton magnetometers are the oldest scalar magnetometers. The first commercial units were produced in early 1960s as portable instruments. In continuation airborne instruments appeared with optimized speed of readings and sensitivity, large sensors etc. Later development of Overhauser and optically pumped magnetometers has eliminated Proton magnetometers from airborne surveys. However they remain very popular in various ground surveys and observatories. With this primary purpose of generating the ground based magnetic data, the Indian Institute of Geomagnetism (IIG) for the last 3 decades have been developing low cost Proton Precession Magnetometers (PPM). Beginning with the 1 nT PPM which has undergone several changes in design, the successor PM7 the advanced version has been successfully developed by the institute and is installed at various observatories of the institute. PM7 records the total field `F' with accuracy of 0.1 nT and a sampling rate of 10 seconds/sample. This article briefly discusses the design and development of this IIG make PM7 and compares the data recorded by this instrument with one of the commercially available Overhauser magnetometer in the world market. The quality of data recorded by PM7 is in excellent agreement with the Overhauser. With the available quality of data generated by this instrument, PM7 is an affordable PPM for scientific institutions, schools and colleges intending to carry out geomagnetic studies. The commercial cost of PM7 is ≈ 20% of the cost of Overhauser available in market.

  1. Proteomics Core

    Data.gov (United States)

    Federal Laboratory Consortium — Proteomics Core is the central resource for mass spectrometry based proteomics within the NHLBI. The Core staff help collaborators design proteomics experiments in a...

  2. Synthesis, magnetic and optical properties of core/shell Co1-xZnxFe2O4/SiO2 nanoparticles

    Science.gov (United States)

    2011-01-01

    The optical properties of multi-functionalized cobalt ferrite (CoFe2O4), cobalt zinc ferrite (Co0.5Zn0.5Fe2O4), and zinc ferrite (ZnFe2O4) nanoparticles have been enhanced by coating them with silica shell using a modified Stöber method. The ferrites nanoparticles were prepared by a modified citrate gel technique. These core/shell ferrites nanoparticles have been fired at temperatures: 400°C, 600°C and 800°C, respectively, for 2 h. The composition, phase, and morphology of the prepared core/shell ferrites nanoparticles were determined by X-ray diffraction and transmission electron microscopy, respectively. The diffuse reflectance and magnetic properties of the core/shell ferrites nanoparticles at room temperature were investigated using UV/VIS double-beam spectrophotometer and vibrating sample magnetometer, respectively. It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases. The cobalt ferrite nanoparticles fired at temperature 800°C; show the highest saturation magnetization while the zinc ferrite nanoparticles coated with silica shell shows the highest diffuse reflectance. On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles. These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications. PMID:21774807

  3. Development of Autonomous Magnetometer Rotorcraft For Wide Area Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Mark D. McKay; Matthew O. Anderson

    2011-08-01

    Large areas across the United States and internationally are potentially contaminated with unexploded ordinance (UXO), with some ranges encompassing tens to hundreds of thousands of acres. Technologies are needed which will allow for cost effective wide area scanning with (1) near 100% coverage and (2) near 100% detection of subsurface ordnance or features indicative of subsurface ordnance. The current approach to wide area assessment is a multi-level one, in which medium - altitude fixed wing optical imaging is used for an initial site assessment. This assessment is followed with low altitude manned helicopter based magnetometry. Subsequent to this wide area assessment targeted surface investigations are performed using either towed geophysical sensor arrays or man portable sensors. In order to be an effective tool for small UXO detection, the sensing altitude for magnetic site investigations needs to be on the order of 1 to 3 meters. These altitude requirements mean that manned helicopter surveys will generally only be feasible in large, open and relatively flat terrains. While such surveys are effective in mapping large areas relatively fast there are substantial mobilization/demobilization, staffing and equipment costs associated with these surveys, resulting in costs of approximately $100-$150/acre. In addition, due to the low altitude there are substantial risks to pilots and equipment. Surface towed arrays provide highresolution maps but have other limitations, e.g. in their ability to navigate rough terrain effectively. Thus there is a need for other systems, which can be used for effective data collection. An Unmanned Aerial Vehicle (UAV) magnetometer platform is an obvious alternative. The motivation behind such a system is that it reduces risk to operators, is lower in initial and Operational and Maintenance (O&M) costs (and can thus potentially be applied to smaller sites) and has the potential of being more effective in terms of detection and possibly

  4. Theory of graphene saturable absorption

    Science.gov (United States)

    Marini, A.; Cox, J. D.; García de Abajo, F. J.

    2017-03-01

    Saturable absorption is a nonperturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Specifically, we theoretically investigate saturable absorption in extended graphene by developing a semianalytical nonperturbative single-particle approach, describing electron dynamics in the atomically-thin material using the two-dimensional Dirac equation for massless Dirac fermions, which is recast in the form of generalized Bloch equations. By solving the electron dynamics nonperturbatively, we account for both interband and intraband contributions to the intensity-dependent saturated conductivity and conclude that the former dominates regardless of the intrinsic doping state of the material. We obtain results in qualitative agreement with atomistic quantum-mechanical simulations of graphene nanoribbons including electron-electron interactions, finite-size, and higher-band effects. Remarkably, such effects are found to affect mainly the linear absorption, while the predicted saturation intensities are in good quantitative agreement in the limit of extended graphene. Additionally, we find that the modulation depth of saturable absorption in graphene can be electrically manipulated through an externally applied gate voltage. Our results are relevant for the development of graphene-based optoelectronic devices, as well as for applications in mode-locking and random lasers.

  5. The absolute magnetometers on board Swarm, lessons learned from more than two years in space

    DEFF Research Database (Denmark)

    Hulot, Gauthier; Leger, Jean-Michel; Vigneron, Pierre

    ESA's Swarm satellites carry 4He absolute magnetometers (ASM), designed by CEA-Léti and developed in partnership with CNES. These instruments are the first-ever space-borne magnetometers to use a common sensor to simultaneously deliver 1Hz independent absolute scalar and vector readings of the ma......ESA's Swarm satellites carry 4He absolute magnetometers (ASM), designed by CEA-Léti and developed in partnership with CNES. These instruments are the first-ever space-borne magnetometers to use a common sensor to simultaneously deliver 1Hz independent absolute scalar and vector readings...... of the magnetic field. They have provided the very high accuracy scalar field data nominally required by the mission (for both science and calibration purposes, since each satellite also carries a low noise high frequency fluxgate magnetometer designed by DTU), but also very useful experimental absolute vector...... the advantages of flying ASM instruments on space-borne magnetic missions for data quality checks, geomagnetic field modeling and science objectives....

  6. Statistical optimization of effective parameters on saturation magnetization of nanomagnetite particles

    Energy Technology Data Exchange (ETDEWEB)

    Ramimoghadam, Donya [Nanotechnology & Catalysis Research Centre (NANOCAT), IPS Building, University of Malaya, 50603 Kuala Lumpur (Malaysia); Bagheri, Samira, E-mail: samira_bagheri@edu.um.my [Nanotechnology & Catalysis Research Centre (NANOCAT), IPS Building, University of Malaya, 50603 Kuala Lumpur (Malaysia); Yousefi, Amin Termeh [ChECA IKohza, Department of Environmental & Green Technology (EGT), Malaysia Japan International Institute of Technology (MJIIT), University Technology Malaysia - UTM, Kuala Lumpur (Malaysia); Abd Hamid, Sharifah Bee [Nanotechnology & Catalysis Research Centre (NANOCAT), IPS Building, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-11-01

    In this study, nanomagnetite particles have been successfully prepared via the coprecipitation method. The effect of the key explanatory variables on the saturation magnetization of synthetic nanomagnetite particles was investigated using the response surface methodology (RSM). The correlation of the involved parameters with the growth process was examined by employing the central composite design method through designating set up experiments that will determine the interaction of the variables. The vibrating sample magnetometer (VSM) was used to confirm the statistical analysis. Furthermore, the regression analysis monitors the priority of the variables' influence on the saturation magnetization of nanomagnetite particles by developing the statistical model of the saturation magnetization. According to the investigated model, the highest interaction of variable belongs to the pH and temperature with the optimized condition of 9–11, and 75–85 °C, respectively. The response obtained by VSM suggests that the saturation magnetization of nanomagnetite particles can be controlled by restricting the effective parameters. - Highlights: • Nanomagnetite particles have been prepared via the coprecipitation method. • Effects of key variables on M{sub s} of synthetic nanomagnetite investigated by RSM. • The VSM was used to confirm the statistical analysis. • Optimized condition belongs to pH of 9–11, and temperature of 75–85 °C.

  7. A novel green synthesis of Fe3O4-Ag core shell recyclable nanoparticles using Vitis vinifera stem extract and its enhanced antibacterial performance

    Science.gov (United States)

    Venkateswarlu, Sada; Natesh Kumar, B.; Prathima, B.; Anitha, K.; Jyothi, N. V. V.

    2015-01-01

    We described a novel and eco-friendly method for preparing Fe3O4-Ag core shell nanoparticles (CSNPs) with high magnetism and potent antibacterial activity. The Fe3O4-Ag CSNPs were obtained using waste material of Vitis vinifera (grape) stem extract as the green solvent, reducing and capping agent. The result recorded from X-ray powder diffraction (XRD), UV-vis spectrum, energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) supports the biosynthesis and characterization of Fe3O4-Ag CSNPs. From transmission electron microscopy (TEM) the size of the Fe3O4-Ag nanoparticles was measured below 50 nm; high-resolution TEM (HRTEM) indicates the core shell structure; and selected area electron diffraction (SAED) has revealed polycrystalline nature. Vibrating sample magnetometer (VSM) shows the ferromagnetic nature of Fe3O4-Ag CSNPs at room temperature with saturation magnetization of 15.74 emu/g. Further, these biogenic nanoparticles were highly hazardous to microorganisms. The antibacterial activity of biogenic Fe3O4-Ag CSNPs showed potent inhibitory activity against both Gram-positive and Gram-negative pathogens. These nanoparticles may also be reusable because of its excellent ferromagnetic property.

  8. A novel green synthesis of Fe{sub 3}O{sub 4}-Ag core shell recyclable nanoparticles using Vitis vinifera stem extract and its enhanced antibacterial performance

    Energy Technology Data Exchange (ETDEWEB)

    Venkateswarlu, Sada; Natesh Kumar, B.; Prathima, B. [Analytical and inorganic Division of Chemistry, S.V. University, Tirupati-517502, Andhra Pradesh (India); Anitha, K. [Department of Chemistry, S.K. University, Anantapur-515003, Andhra Pradesh (India); Jyothi, N.V.V., E-mail: nvvjyothi01@gmail.com [Analytical and inorganic Division of Chemistry, S.V. University, Tirupati-517502, Andhra Pradesh (India)

    2015-01-15

    We described a novel and eco-friendly method for preparing Fe{sub 3}O{sub 4}-Ag core shell nanoparticles (CSNPs) with high magnetism and potent antibacterial activity. The Fe{sub 3}O{sub 4}-Ag CSNPs were obtained using waste material of Vitis vinifera (grape) stem extract as the green solvent, reducing and capping agent. The result recorded from X-ray powder diffraction (XRD), UV–vis spectrum, energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) supports the biosynthesis and characterization of Fe{sub 3}O{sub 4}-Ag CSNPs. From transmission electron microscopy (TEM) the size of the Fe{sub 3}O{sub 4}-Ag nanoparticles was measured below 50 nm; high-resolution TEM (HRTEM) indicates the core shell structure; and selected area electron diffraction (SAED) has revealed polycrystalline nature. Vibrating sample magnetometer (VSM) shows the ferromagnetic nature of Fe{sub 3}O{sub 4}-Ag CSNPs at room temperature with saturation magnetization of 15.74 emu/g. Further, these biogenic nanoparticles were highly hazardous to microorganisms. The antibacterial activity of biogenic Fe{sub 3}O{sub 4}-Ag CSNPs showed potent inhibitory activity against both Gram-positive and Gram-negative pathogens. These nanoparticles may also be reusable because of its excellent ferromagnetic property.

  9. A magnetometer-free indoor human localization based on loosely coupled IMU/UWB fusion.

    Science.gov (United States)

    Zihajehzadeh, Shaghayegh; Yoon, Paul K; Park, Edward J

    2015-01-01

    The magnetic distortions in indoor environment affects the accuracy of yaw angle estimation using magnetometer. Thus, the accuracy of indoor localization based on inertial-magnetic sensors will be affected as well. To address this issue, this paper proposes a magnetometer-free solution for indoor human localization and yaw angle estimation. The proposed algorithm fuses a wearable inertial sensor consisting of MEMS-based accelerometer and gyroscope with a portable ultra-wideband (UWB) localization system in a cascaded two-step filter consisting of a tilt Kalman filter and a localization Kalman filter. By benchmarking against an optical motion capture system, the experimental results show that the proposed algorithm can accurately track position and velocity as well as the yaw angle without using magnetometer.

  10. Construction and calibration of a low cost and fully automated vibrating sample magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    El-Alaily, T.M., E-mail: toson_alaily@yahoo.com [Physics Department, Faculty of Science, Tanta University, Tanta (Egypt); El-Nimr, M.K.; Saafan, S.A.; Kamel, M.M.; Meaz, T.M. [Physics Department, Faculty of Science, Tanta University, Tanta (Egypt); Assar, S.T. [Engineering Physics and Mathematics Department, Faculty of Engineering, Tanta University, Tanta (Egypt)

    2015-07-15

    A low cost vibrating sample magnetometer (VSM) has been constructed by using an electromagnet and an audio loud speaker; where both are controlled by a data acquisition device. The constructed VSM records the magnetic hysteresis loop up to 8.3 KG at room temperature. The apparatus has been calibrated and tested by using magnetic hysteresis data of some ferrite samples measured by two scientifically calibrated magnetometers; model (Lake Shore 7410) and model (LDJ Electronics Inc. Troy, MI). Our VSM lab-built new design proved success and reliability. - Highlights: • A low cost automated vibrating sample magnetometer VSM has been constructed. • The VSM records the magnetic hysteresis loop up to 8.3 KG at room temperature. • The VSM has been calibrated and tested by using some measured ferrite samples. • Our VSM lab-built new design proved success and reliability.

  11. Ice cores

    DEFF Research Database (Denmark)

    Svensson, Anders

    2014-01-01

    Ice cores from Antarctica, from Greenland, and from a number of smaller glaciers around the world yield a wealth of information on past climates and environments. Ice cores offer unique records on past temperatures, atmospheric composition (including greenhouse gases), volcanism, solar activity......, dustiness, and biomass burning, among others. In Antarctica, ice cores extend back more than 800,000 years before present (Jouzel et al. 2007), whereas. Greenland ice cores cover the last 130,000 years...

  12. Gamma-magnetic normalization - new effect to reduce flux-gate magnetometer noise level

    Science.gov (United States)

    Korepanov, V.

    2012-04-01

    It is the author's opinion confirmed by numerous experiments, that the FGM noise level (NL) is determined not by Barkhausen jumps during the core remagnetization from positive to negative state as the majority of designers believe, but by non-repeatability of the magnetic domains transition from negative to positive states and back. This shows the way how to reduce the magnetic noise: to manufacture the magnetic material with a structure which will create conditions for magnetic domain walls to glide easily and uniformly when changing their orientation leading to minimal efforts at cyclic remagnetization. Ideally, such a material may be represented as a solid "liquid" with freely floating uniform magnetic domains without walls friction. To reduce the specific NL of the materials, several post-melting processing technologies were developed. A set of experiments made by many investigators has shown that the best results gives the magnetic materials annealing in vacuum or in any inert gas applying by this during all annealing time the alternative magnetic field, imitating core excitation field during FGM operation. If to accept the "solid liquid" model, this mechanism of NL decreasing has clear physical explanation: permanent re-magnetization of domains leads to the structural improvements favorable namely for the homogenization of transitions, rise of temperature gives necessary energy for the impurities liquidation. Probably, M. Acuna was the first who reported that during FGM operation in space its NL is decreasing with time and attributed this to the relaxation of mechanical stresses in the core material in weightlessness conditions [1]. We studied in details the conditions in which the core material is in space: weightlessness, vacuum and radiation. Mechanical stresses relaxation hypothesis was rejected because the internal forces in any solid body are much stronger as those to which a gravity force might have influence. Also the tests of FGM sensor in vacuum

  13. On the control of magnetic perturbing field onboard landers: the Magnetometer Protection program for the ESA ExoMars/Humboldt MSMO magnetometer experiment

    DEFF Research Database (Denmark)

    Menvielle, M.; Primdahl, Fritz; Brauer, Peter

    as characterizing its sub-surface. Magnetic fields are generated by electric currents in the planetary space environment, induced currents in the planetary interior and possibly remanent magnetism. In consequence, hardly any other single physical quantity can be used in such a variety of studies related......Magnetic field observations at a planetary surface have a wide potential of scientific applications, ranging from processes in the dynamic interaction between the planet environment and the solar wind, to determining the structure and thermal evolution of the interior of the planet as well...... to planetary research. The major difficulty in implementing a magnetometer experiment onboard a lander is to achieve at acceptable costs a good Magnetometer Protection, namely to control the perturbing magnetic field generated by the lander during operations at the planetary surfa ce, so as to achieve...

  14. Swarm's absolute magnetometer experimental vector mode, an innovative capability for space magnetometry

    DEFF Research Database (Denmark)

    Hulot, Gauthier; Vigneron, Pierre; Leger, Jean-Michel

    2015-01-01

    readings of the magnetic eld. Since launch, these ASMs provided very high accuracy scalar eld data, as nominally required for the mission, together with experimental vector eld data. Here, we compare geomagnetic eld models built from such ASM-only data with models built from the mission's nominal 1Hz data......, combining ASM scalar data with independent uxgate magnetometer vector data. The high level of agreement between these models demonstrates the potential of the ASM's vector mode for data quality control and as a stand alone magnetometer, and illustrates the way the evolution of key eld features can easily...

  15. Integrated high-transition temperature magnetometer with only two superconducting layers

    DEFF Research Database (Denmark)

    Kromann, R.; Kingston, J.J.; Miklich, A.H.

    1993-01-01

    We describe the fabrication and testing of an integrated YBa2Cu3O7-x thin-film magnetometer consisting of a dc superconducting quantum interference device (SQUID), with biepitaxial grain boundary junctions, integrated with a flux transformer on a single substrate. Only two superconducting layers...... are required, the SQUID body serving as the crossunder that completes the multiturn flux transformer. The highest temperature at which any of the magnetometers functioned was 76 K. At 60 K the magnetic field gain of this device was 63, and the magnetic field noise was 160 fT Hz-1/2 at 2 kHz, increasing to 3...

  16. Study of 3He Rabi nutations by optically-pumped cesium magnetometers

    Science.gov (United States)

    Koch, Hans-Christian; Bison, Georg; Grujić, Zoran Dragan; Heil, Werner; Kasprzak, Malgorzata; Knowles, Paul; Kraft, Andreas; Pazgalev, Anatoly; Schnabel, Allard; Voigt, Jens; Weis, Antoine

    2017-10-01

    We describe a method for recording the Rabi nutation of nuclear spin polarized 3He by optically pumped cesium magnetometers. The measurement is performed by detecting the time-dependent magnetic field produced by the 3He magnetization. The observed signals are compared to theoretical models and the results are used to precisely trace the evolution of the magnetization. This procedure represents a convenient way to control and measure the Rabi flip angle and the degree of spin polarization in experiments using 3He magnetometers. The method requires only very coarse knowledge of the applied magnetic field's magnitude.

  17. Development of a magnetometer-based search strategy for stopped monopoles at the Large Hadron Collider

    CERN Document Server

    De Roeck, A.; Hirt, A M; Joergensen, M-D; Katre, A; Mermod, P; Milstead, D; Sloan, T

    2012-01-01

    If produced in high energy particle collisions at the LHC, magnetic monopoles could stop in material surrounding the interaction points. Obsolete parts of the beam pipe near the CMS interaction region, which were exposed to the products of pp and heavy ion collisions, were analysed using a SQUID-based magnetometer. The purpose of this work is to quantify the performance of the magnetometer in the context of a monopole search using a small set of samples of accelerator material ahead of the 2013 shutdown.

  18. Systematic ultrasound-guided saturation and template biopsy of the prostate: Indications and advantages of extended sampling

    NARCIS (Netherlands)

    Isbarn, H.; Briganti, B.; Visschere, P.J. De; Futterer, J.J.; Ghadjar, P.; Giannarini, G.; Ost, P.; Ploussard, G.; Sooriakumaran, P.; Surcel, C.; Oort, I.M. van; Yossepowitch, O.; Bergh, R. van den

    2015-01-01

    OBJECTIVES: Prostate biopsy (PB) is the gold standard for the diagnosis of prostate cancer (PCa). However, the optimal number of biopsy cores remains debatable. We sought to compare contemporary standard (10-12 cores) vs. saturation (=18 cores) schemes on initial as well as repeat PB. METHODS: A

  19. Saturation of the turbulent dynamo.

    Science.gov (United States)

    Schober, J; Schleicher, D R G; Federrath, C; Bovino, S; Klessen, R S

    2015-08-01

    The origin of strong magnetic fields in the Universe can be explained by amplifying weak seed fields via turbulent motions on small spatial scales and subsequently transporting the magnetic energy to larger scales. This process is known as the turbulent dynamo and depends on the properties of turbulence, i.e., on the hydrodynamical Reynolds number and the compressibility of the gas, and on the magnetic diffusivity. While we know the growth rate of the magnetic energy in the linear regime, the saturation level, i.e., the ratio of magnetic energy to turbulent kinetic energy that can be reached, is not known from analytical calculations. In this paper we present a scale-dependent saturation model based on an effective turbulent resistivity which is determined by the turnover time scale of turbulent eddies and the magnetic energy density. The magnetic resistivity increases compared to the Spitzer value and the effective scale on which the magnetic energy spectrum is at its maximum moves to larger spatial scales. This process ends when the peak reaches a characteristic wave number k☆ which is determined by the critical magnetic Reynolds number. The saturation level of the dynamo also depends on the type of turbulence and differs for the limits of large and small magnetic Prandtl numbers Pm. With our model we find saturation levels between 43.8% and 1.3% for Pm≫1 and between 2.43% and 0.135% for Pm≪1, where the higher values refer to incompressible turbulence and the lower ones to highly compressible turbulence.

  20. Slow light in saturable absorbers

    OpenAIRE

    Macke, Bruno; Ségard, Bernard

    2008-01-01

    International audience; In connection with the experiments recently achieved on doped crystals, biological samples, doped optical fibers and semiconductor heterostructures, we revisit the theory of the propagation of a pulse-modulated light in a saturable absorber. Explicit analytical expressions of the transmitted pulse are obtained, enabling us to determine the parameters optimizing the time-delay of the transmitted pulse with respect to the incident pulse. We finally compare the maximum fr...

  1. Saturation of Van Allen's belts

    CERN Document Server

    Le Bel, E

    2002-01-01

    The maximum number of electrons that can be trapped in van Allen's belts has been evaluated at CEA-DAM more precisely than that commonly used in the space community. The modelization that we have developed allows to understand the disagreement (factor 50) observed between the measured and predicted electrons flux by US satellites and theory. This saturation level allows sizing-up of the protection on a satellite in case of energetic events. (authors)

  2. Transition to Turbulent Dynamo Saturation

    Science.gov (United States)

    Seshasayanan, Kannabiran; Gallet, Basile; Alexakis, Alexandros

    2017-11-01

    While the saturated magnetic energy is independent of viscosity in dynamo experiments, it remains viscosity dependent in state-of-the-art 3D direct numerical simulations (DNS). Extrapolating such viscous scaling laws to realistic parameter values leads to an underestimation of the magnetic energy by several orders of magnitude. The origin of this discrepancy is that fully 3D DNS cannot reach low enough values of the magnetic Prandtl number Pm. To bypass this limitation and investigate dynamo saturation at very low Pm, we focus on the vicinity of the dynamo threshold in a rapidly rotating flow: the velocity field then depends on two spatial coordinates only, while the magnetic field consists of a single Fourier mode in the third direction. We perform numerical simulations of the resulting set of reduced equations for Pm down to 2 ×10-5. This parameter regime is currently out of reach to fully 3D DNS. We show that the magnetic energy transitions from a high-Pm viscous scaling regime to a low-Pm turbulent scaling regime, the latter being independent of viscosity. The transition to the turbulent saturation regime occurs at a low value of the magnetic Prandtl number, Pm ≃10-3 , which explains why it has been overlooked by numerical studies so far.

  3. SATURATED PICRIC ACID PREVENTS AUTOPHAGIA

    Directory of Open Access Journals (Sweden)

    V Rahimi-Movaghar

    2008-08-01

    Full Text Available "nThe dysesthesia and paresthesia that occurs in laboratory rats after spinal cord injury (SCI results in autophagia. This self-destructive behavior interferes with functional assessments in designed studies and jeopardizes the health of the injured rat. In this study, we evaluated role of saturated picric acid in the prevention of autophagia and self-mutilation. All rats were anesthetized with an intraperitoneal injection of a mixture of ketamine (100 mg/kg and xylazine (10 mg/kg for the SCI procedures. In the first 39 rats, no solution applied to the hind limbs, but in the next 26 cases, we smeared the saturated picric acid on the tail, lower extremities, pelvic, and abdomen of the rats immediately after SCI. In the rats without picric acid, 23 rats died following autophagia, but in the 26 rats with picric acid, there was no autophagia (P < 0.001. Picric acid side effects in skin and gastrointestinal signs such as irritation, redness and diarrhea were not seen in any rat. Saturated picric acid is a topical solution that if used appropriately and carefully, might be safe and effectively prevents autophagia and self-mutilation. When the solution is applied to the lower abdomen and limbs, we presume that its bitterness effectively prevents the rat from licking and biting the limb.

  4. Comparison between SuperDARN flow vectors and equivalent ionospheric currents from ground magnetometer arrays

    DEFF Research Database (Denmark)

    Weygand, J. M.; Amm, O.; Angelopoulos, V.

    2012-01-01

    that may influence the alignment include ionospheric conductivity gradients and quiet time backgrounds. Our results can be used to approximate the macroscopic (similar to 1000 km) ionospheric convection patterns. The SECS maps represent a value-added product from the raw magnetometer database and can...

  5. Periodic H2 Synthesis for Spacecraft Attitude Determination and Control with a Vector Magnetometer and Magnetorquers

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Stoustrup, Jakob

    2001-01-01

    the expected magnetic field vector and the true magnetometer data is used for the attitude determination. The magnetic attitude control and determination is intrinsically periodic due to periodic nature of the geomagnetic field variation in orbit. The control performance is specified by the generalized H2...

  6. MgB2 magnetometer with directly coupled pick-up loop

    NARCIS (Netherlands)

    Portesi, C.; Mijatovic, D.; Veldhuis, Dick; Brinkman, Alexander; Monticone, E.; Gonnelli, R.S.

    2006-01-01

    magnetometer with a directly coupled pick-up loop. We used an all in situ technique for fabricating magnesium diboride films, which consists of the co-evaporation of B and Mg by means of an e-gun and a resistive heater respectively. Consequently, we realized the superconducting device, which

  7. Performance Improvement of Inertial Navigation System by Using Magnetometer with Vehicle Dynamic Constraints

    Directory of Open Access Journals (Sweden)

    Daehee Won

    2015-01-01

    Full Text Available A navigation algorithm is proposed to increase the inertial navigation performance of a ground vehicle using magnetic measurements and dynamic constraints. The navigation solutions are estimated based on inertial measurements such as acceleration and angular velocity measurements. To improve the inertial navigation performance, a three-axis magnetometer is used to provide the heading angle, and nonholonomic constraints (NHCs are introduced to increase the correlation between the velocity and the attitude equation. The NHCs provide a velocity feedback to the attitude, which makes the navigation solution more robust. Additionally, an acceleration-based roll and pitch estimation is applied to decrease the drift when the acceleration is within certain boundaries. The magnetometer and NHCs are combined with an extended Kalman filter. An experimental test was conducted to verify the proposed method, and a comprehensive analysis of the performance in terms of the position, velocity, and attitude showed that the navigation performance could be improved by using the magnetometer and NHCs. Moreover, the proposed method could improve the estimation performance for the position, velocity, and attitude without any additional hardware except an inertial sensor and magnetometer. Therefore, this method would be effective for ground vehicles, indoor navigation, mobile robots, vehicle navigation in urban canyons, or navigation in any global navigation satellite system-denied environment.

  8. Characterization and demonstration results of a SQUID magnetometer system developed for geomagnetic field measurements

    Science.gov (United States)

    Kawai, J.; Miyamoto, M.; Kawabata, M.; Nosé, M.; Haruta, Y.; Uehara, G.

    2017-08-01

    We characterized a low temperature superconducting quantum interference device (SQUID) magnetometer system developed for high-sensitivity geomagnetic field measurement, and demonstrated the detection of weak geomagnetic signals. The SQUID magnetometer system is comprised of three-axis SQUID magnetometers housed in a glass fiber reinforced plastic cryostat, readout electronics with flux locked loop (FLL), a 24-bit data logger with a global positioning system and batteries. The system noise was approximately 0.2 pT √Hz- 1/2 in the 1-50 Hz frequency range. This performance was determined by including the thermal noise and the shielding effect of the copper shield, which covered the SQUID magnetometers to eliminate high-frequency interference. The temperature drift of the system was ˜0.8 pT °C- 1 in an FLL operation. The system operated for a month using 33 l liquid helium. Using this system, we performed the measurements of geomagnetic field in the open-air, far away from the city. The system could detect weak geomagnetic signals such as the Schumann resonance with sixth harmonics, and the ionospheric Alfvén resonance appearing at night, for the north-south and east-west components of the geomagnetic field. We confirm that the system was capable of high-sensitivity measurement of the weak geomagnetic activities.

  9. A game-theoretic approach for calibration of low-cost magnetometers under noise uncertainty

    Science.gov (United States)

    Siddharth, S.; Ali, A. S.; El-Sheimy, N.; Goodall, C. L.; Syed, Z. F.

    2012-02-01

    Pedestrian heading estimation is a fundamental challenge in Global Navigation Satellite System (GNSS)-denied environments. Additionally, the heading observability considerably degrades in low-speed mode of operation (e.g. walking), making this problem even more challenging. The goal of this work is to improve the heading solution when hand-held personal/portable devices, such as cell phones, are used for positioning and to improve the heading estimation in GNSS-denied signal environments. Most smart phones are now equipped with self-contained, low cost, small size and power-efficient sensors, such as magnetometers, gyroscopes and accelerometers. A magnetometer needs calibration before it can be properly employed for navigation purposes. Magnetometers play an important role in absolute heading estimation and are embedded in many smart phones. Before the users navigate with the phone, a calibration is invoked to ensure an improved signal quality. This signal is used later in the heading estimation. In most of the magnetometer-calibration approaches, the motion modes are seldom described to achieve a robust calibration. Also, suitable calibration approaches fail to discuss the stopping criteria for calibration. In this paper, the following three topics are discussed in detail that are important to achieve proper magnetometer-calibration results and in turn the most robust heading solution for the user while taking care of the device misalignment with respect to the user: (a) game-theoretic concepts to attain better filter parameter tuning and robustness in noise uncertainty, (b) best maneuvers with focus on 3D and 2D motion modes and related challenges and (c) investigation of the calibration termination criteria leveraging the calibration robustness and efficiency.

  10. Promoter analysis by saturation mutagenesis

    Directory of Open Access Journals (Sweden)

    Baliga Nitin

    2001-01-01

    Full Text Available Gene expression and regulation are mediated by DNA sequences, in most instances, directly upstream to the coding sequences by recruiting transcription factors, regulators, and a RNA polymerase in a spatially defined fashion. Few nucleotides within a promoter make contact with the bound proteins. The minimal set of nucleotides that can recruit a protein factor is called a cis-acting element. This article addresses a powerful mutagenesis strategy that can be employed to define cis-acting elements at a molecular level. Technical details including primer design, saturation mutagenesis, construction of promoter libraries, phenotypic analysis, data analysis, and interpretation are discussed.

  11. Semiconductor saturable absorbers for ultrafast terahertz signals

    OpenAIRE

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    We demonstrate saturable absorber behavior of n-type semiconductors GaAs, GaP, and Ge in the terahertz THz frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum states, due to conduction band onparabolicity and scattering into satellite valleys in strong THz fields. Saturable absorber parameters, such as linear and nonsaturable transmission, and saturation fluen...

  12. Semiconductor saturable absorbers for ultrafast terahertz signals

    OpenAIRE

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    We demonstrate saturable absorber behavior of n-type semiconductorsGaAs,GaP, and Ge in the terahertz (THz) frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum states, due to conduction band nonparabolicity and scattering into satellite valleys in strong THz fields. Saturable absorber parameters, such as linear and nonsaturable transmission, and saturation flue...

  13. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2008-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  14. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2010-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  15. Mission objectives and scientific rationale for the magnetometer mission.

    Science.gov (United States)

    Langel, R. A.

    1991-12-01

    Based on a review of the characteristics of the geomagnetic field, objectives for the magnetic portion of the ARISTOTELES mission are: (1) To derive a description of the main magnetic field and its secular variation. (2) To investigate the correlation between the geomagnetic field and variations in the length of day. (3) To study properties of the fluid core. (4) To study the conductivity of the mantle. (5) To model the state and evolution of the crust and upper lithosphere. (6) To measure and characterize field aligned currents and ionospheric currents and to understand their generation mechanisms and their role in energy coupling in the interplanetary-magnetospheric-ionospheric systems. Procedures for these investigations are outlined.

  16. Input-output linearizing tracking control of induction machine with the included magnetic saturation

    DEFF Research Database (Denmark)

    Dolinar, Drago; Ljusev, Petar; Stumberger, Gorazd

    2003-01-01

    The tracking control design of an induction motor, based on input-output linearisation with magnetic saturation included is addressed. The magnetic saturation is represented by a nonlinear magnetising curve for the iron core and is used in the control, the observer of the state variables......, and in the load torque estimator. An input-output linearising control is used to achieve better tracking performances. It is based on the mixed 'stator current - rotor flux linkage' induction motor model with magnetic saturation considered in the stationary reference frame. Experimental results show...... that the proposed input-output linearising tracking control with saturation included behaves considerably better than the one without saturation, and that it introduces smaller position and speed errors, and better motor stiffness on account of the increased computational complexity....

  17. Impact of magnetic saturation on the input-output linearising tracking control of an induction motor

    DEFF Research Database (Denmark)

    Dolinar, Drago; Ljusev, Petar; Stumberger, Gorazd

    2004-01-01

    This paper deals with the tracking control design of an induction motor, based on input-output linearization with magnetic saturation included. Magnetic saturation is represented by the nonlinear magnetizing curve of the iron core and is used in the control design, the observer of state variables......, and in the load torque estimator. An input-output linearising control is used to achieve better tracking performances of the drive. It is based on the mixed ”stator current - rotor flux linkage” induction motor model with magnetic saturation considered in the stationary reference frame. Experimental results show...... that the proposed input-output linearising tracking control with the included saturation behaves considerably better than the one without saturation, and that it introduces smaller position and speed errors, and better motor stiffness on account of the increased computational complexity....

  18. The use of saturation in qualitative research.

    Science.gov (United States)

    Walker, Janiece L

    2012-01-01

    Understanding qualitative research is an important component of cardiovascular nurses' practice and allows them to understand the experiences, stories, and perceptions of patients with cardiovascular conditions. In understanding qualitative research methods, it is essential that the cardiovascular nurse understands the process of saturation within qualitative methods. Saturation is a tool used for ensuring that adequate and quality data are collected to support the study. Saturation is frequently reported in qualitative research and may be the gold standard. However, the use of saturation within methods has varied. Hence, the purpose of this column is to provide insight for the cardiovascular nurse regarding the use of saturation by reviewing the recommendations for which qualitative research methods it is appropriate to use and how to know when saturation is achieved. In understanding saturation, the cardiovascular nurse can be a better consumer of qualitative research.

  19. Development of Geomagnetic Monitoring System Using a Magnetometer for the Field

    Science.gov (United States)

    Lee, Young-Cheol; Kim, Sung-Wook; Choi, Eun-Kyeong; Kim, In-Soo

    2014-05-01

    Three institutes including KMA (Korea Meteorological Administration), KSWC (Korean Space Weather Center) of NRRA (National Radio Research Agency) and KIGAM (Korea Institute of Geoscience and Mineral Resources) are now operating magnetic observatories. Those observatories observe the total intensity and three components of geomagnetic element. This paper comes up with a magnetic monitoring system now under development that uses a magnetometer for field survey. In monitoring magnetic variations in areas (active faults or volcanic regions), more reliable results can be obtained when an array of several magnetometers are used rather than a single magnetometer. In order to establish and operate a magnetometer array, such factors as expenses, convenience of the establishment and operation of the array should be taken into account. This study has come up with a magnetic monitoring system complete with a magnetometer for the field survey of our own designing. A magnetic monitoring system, which is composed of two parts. The one is a field part and the other a data part. The field part is composed of a magnetometer, an external memory module, a power supply and a set of data transmission equipment. The data part is a data server which can store the data transmitted from the field part, analyze the data and provide service to the web. This study has developed an external memory module for ENVI-MAG (Scintrex Ltd.) using an embedded Cortex-M3 board, which can be programmed, attach other functional devices (SD memory cards, GPS antennas for time synchronization, ethernet cards and so forth). The board thus developed can store magnetic measurements up to 8 Gbytes, synchronize with the GPS time and transmit the magnetic measurements to the data server which is now under development. A monitoring system of our own developing was installed in Jeju island, taking measurements throughout Korea. Other parts including a data transfer module, a server and a power supply using solar

  20. One-step approach for the synthesis of CoFe2O4@rGO core-shell nanocomposites as efficient adsorbent for removal of organic pollutants.

    Science.gov (United States)

    Song, Z J; Ran, W; Wei, F Y

    2017-01-01

    CoFe2O4-reduced graphene oxide nanocomposites (CFG) have been successfully synthesized via one-step solvothermal method. The prepared CFG are characterized by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy (FESEM), vibrating sample magnetometer and so on. The FESEM results show that CFG have uniform core-shell structure with an average diameter of about 75 nm and the thickness of the outer graphene shell is about 15-20 nm. The mass ratio of CoFe2O4 to graphene oxide is a key factor affecting the formation of core-shell hybrids. CFG display much higher adsorption capacity for anionic dyes than cationic dyes owing to the favorable electrostatic interaction. The adsorption capacity for methyl orange is observed as high as 263 mg g-1 at 298 K, and the adsorption isotherms follow the Langmuir model. Furthermore, the specific saturation magnetization (Ms) of CFG is 32.8 emu g-1, and the as-synthesized nanocomposites can be easily separated by external magnetic field after adsorption. The results suggest that CFG have great potential for the practical industrial wastewater treatment.

  1. Inferring immobile and in-situ water saturation from laboratory and field measurements

    Energy Technology Data Exchange (ETDEWEB)

    Belen, Rodolfo P., Jr.

    2000-06-01

    Analysis of experimental data and numerical simulation results of dynamic boiling experiments revealed that there is an apparent correlation between the immobile water saturation and the shape of the steam saturation profile. An elbow in the steam saturation profile indicates the sudden drop in steam saturation that marks the transition from steam to two-phase conditions inside the core during boiling. The immobile water saturation can be inferred from this elbow in the steam saturation profile. Based on experimental results obtained by Satik (1997), the inferred immobile water saturation of Berea sandstone was found to be about 0.25, which is consistent with results of relative permeability experiments reported by Mahiya (1999). However, this technique may not be useful in inferring the immobile water saturation of less permeable geothermal rocks because the elbow in the steam saturation profile is less prominent. Models of vapor and liquid-dominated geothermal reservoirs that were developed based on Darcy's law and material and energy conservation equations proved to be useful in inferring the in-situ and immobile water saturations from field measurements of cumulative mass production, discharge enthalpy, and downhole temperature. Knowing rock and fluid properties, and the difference between the stable initial, T{sub o}, and dry-out, T{sub d}, downhole temperatures, the in-situ and immobile water saturations of vapor-dominated reservoirs can be estimated. On the other hand, the in-situ and immobile water saturations, and the change in mobile water content of liquid-dominated reservoirs can be inferred from the cumulative mass production, {Delta}m, and enthalpy, h{prime}, data. Comparison with two-phase, radial flow, numerical simulation results confirmed the validity and usefulness of these models.

  2. Core BPEL

    DEFF Research Database (Denmark)

    Hallwyl, Tim; Højsgaard, Espen

    extensions. Combined with the fact that the language definition does not provide a formal semantics, it is an arduous task to work formally with the language (e.g. to give an implementation). In this paper we identify a core subset of the language, called Core BPEL, which has fewer and simpler constructs......, does not allow omissions, and does not contain ignorable elements. We do so by identifying syntactic sugar, including default values, and ignorable elements in WS-BPEL. The analysis results in a translation from the full language to the core subset. Thus, we reduce the effort needed for working...... formally with WS-BPEL, as one, without loss of generality, need only consider the much simpler Core BPEL. This report may also be viewed as an addendum to the WS-BPEL standard specification, which clarifies the WS-BPEL syntax and presents the essential elements of the language in a more concise way...

  3. Ice Cores

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature, precipitation, atmospheric trace gases, and other aspects of climate and environment derived from ice cores drilled on glaciers and ice...

  4. Core benefits

    National Research Council Canada - National Science Library

    Keith, Brian W

    2010-01-01

    This SPEC Kit explores the core employment benefits of retirement, and life, health, and other insurance -benefits that are typically decided by the parent institution and often have significant governmental regulation...

  5. Hollow Core?

    Science.gov (United States)

    Qiao, G. J.; Liu, J. F.; Wang, Yang; Wu, X. J.; Han, J. L.

    We carried out the Gaussian fitting to the profile of PSR B1237+25 and found that six components rather than five are necessary to make a good fit. In the central part, we found that the core emission is not filled pencil beam but is a small hollow cone. This implies that the impact angle could be $\\beta<0.5^\\circ$. The ``hollow core'' is in agreement with Inverse Compton Scattering model of radio pulsars.

  6. IceBridge Geometrics 823A Cesium Magnetometer L1B Time-Tagged Magnetic Field, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Geometrics 823A Cesium Magnetometer L1B Time-Tagged Magnetic Field (IMGEO1B) data set contains magnetic field strength measurements taken over...

  7. Monitoring geomagnetic signals of groundwater movement using multiple underground SQUID magnetometers

    Directory of Open Access Journals (Sweden)

    Henry S.

    2014-01-01

    Full Text Available Groundwater can influence the geomagnetic field measured underground in at least two key ways. The water levels in rock will determine its electrical conductivity, and thus change the magnitude of the telluric currents induced in the rock by changing magnetic fields generated in the ionosphere. This can be studied by using multiple magnetometers at different underground locations. Secondly the flow of water through rock will generate a small magnetic signal, of unknown magnitude, through the electrokinetic effect. SQUID magnetometry has the potential to allow passive studies of groundwater changes in complex systems such as karst. We have monitored geomagnetic signals using two SQUID magnetometers at the LSBB underground laboratory, and set an initial limit on the magnitude of the electrokinetic signal. We now plan to carry out a longer term measurement using three SQUID systems as well as fluxgate sensors to track changes in the gradient of the magnetic field across the underground complex.

  8. New type of fluxgate magnetometer for the heart’s magnetic fields detection

    Directory of Open Access Journals (Sweden)

    Rybalko Ruslan

    2015-09-01

    Full Text Available The application area of fluxgate sensors is limited by their sensitivity. Medical researches create high demand on the magnetometers with the characteristics of high accuracy and sensibility for measuring weak magnetic fields produced by the human body, such as the heart‘s magnetic field. Due to the insufficient sensitivity of fluxgate sensors, superconducting magnetometers (SQUID take the dominant position for the cardiomagnetic measurements. They have to be cooled by liquefied gases and it leads to high service costs. Therefore an idea of creating a high sensitive sensor based on fluxgate principles and known methods of measurement is attractive and up to date. This paper is dedicated to the modified flux-gate sensors based on Racetrack technology with a new approach of signal demodulation. The improved fluxgate sensor system provides detection of the heart‘s magnetic field without additional expenditures for use.

  9. On-orbit real-time magnetometer bias determination for micro-satellites without attitude information

    Directory of Open Access Journals (Sweden)

    Zhang Zhen

    2015-10-01

    Full Text Available Due to the disadvantages such as complex calculation, low accuracy of estimation, and being non real time in present methods, a new real-time algorithm is developed for on-orbit magnetometer bias determination of micro-satellites without attitude knowledge in this paper. This method uses the differential value approach. It avoids the impact of quartic nature and uses the iterative method to satisfy real-time applications. Simulation results indicate that the new real-time algorithm is more accurate compared with other methods, which are also tested by an experiment system using real noise data. With the new real-time algorithm, a magnetometer calibration can be taken on-orbit and will reduce the demand for computing power effectively.

  10. Micromechanical ``Trampoline'' Magnetometers for Use in Pulsed Magnetic Fields Exceeding 60 Tesla

    Science.gov (United States)

    Balakirev, F. F.; Boebinger, G. S.; Aksyuk, V.; Gammel, P. L.; Haddon, R. C.; Bishop, D. J.

    1998-03-01

    We present the design, construction, and operation of a novel magnetometer for use in intense pulsed magnetic fields. The magnetometer consists of a silicon micromachined "trampoline" to which the sample is attached. The small size of the device (typically 400 microns on a side) gives a fast mechanical response (10,000 to 50,000 Hz) and extremely high sensitivity (10-11 Am^2, corresponding to 10-13 Am^2/Hz^(1/2)). The device is robust against electrical and mechanical noise and requires no special vibration isolation from the pulsed magnet. As a demonstration, we present data taken in a 60 tesla pulsed magnetic field which show clear de Haas-van Alphen oscillations in a one microgram sample of the organic superconductor K-(BEDT-TTF)_2Cu(NCS)_2.

  11. Laser pumping Cs atom magnetometer of theory research based on gradient tensor measuring

    Energy Technology Data Exchange (ETDEWEB)

    Yang Zhang; Chong Kang; Wang Qingtao; Lei Cheng; Zheng Caiping, E-mail: zhangyang@hrbeu.edu.cn [College of Science, Harbin Engineering University, Harbin 150001 (China)

    2011-02-01

    At present, due to space exploration, military technology, geological exploration, magnetic navigation, medical diagnosis and biological magnetic fields study of the needs of research and development, the magnetometer is given strong driving force. In this paper, it will discuss the theoretical analysis and system design of laser pumping cesium magnetometer, cesium atomic energy level formed hyperfine structure with the I-J coupling, the hyperfine structure has been further split into Zeeman sublevels for the effects of magnetic field. To use laser pump and RF magnetic field make electrons transition in the hyperfine structure to produce the results of magneto-optical double resonance, and ultimately through the resonant frequency will be able to achieve accurate value of the external magnetic field. On this basis, we further have a discussion about magnetic gradient tensor measuring method. To a large extent, it increases the magnetic field measurement of information.

  12. Searching for axion stars and Q-balls with a terrestrial magnetometer network

    Energy Technology Data Exchange (ETDEWEB)

    Jackson Kimball, D. F. [Cal State, East Bay; Budker, D. [UC, Berkeley; Eby, J. [Fermilab; Pospelov, M. [Perimeter Inst. Theor. Phys.; Pustelny, S. [Jagiellonian U.; Scholtes, T. [Fribourg U.; Stadnik, Y. V. [Helmholtz Inst., Mainz; Weis, A. [Fribourg U.; Wickenbrock, A. [Mainz U.

    2017-10-11

    Light (pseudo-)scalar fields are promising candidates to be the dark matter in the Universe. Under certain initial conditions in the early Universe and/or with certain types of self-interactions, they can form compact dark-matter objects such as axion stars or Q-balls. Direct encounters with such objects can be searched for by using a global network of atomic magnetometers. It is shown that for a range of masses and radii not ruled out by existing observations, the terrestrial encounter rate with axion stars or Q-balls can be sufficiently high (at least once per year) for a detection. Furthermore, it is shown that a global network of atomic magnetometers is sufficiently sensitive to pseudoscalar couplings to atomic spins so that a transit through an axion star or Q-ball could be detected over a broad range of unexplored parameter space.

  13. Versatile, high sensitivity, and automatized angular dependent vectorial Kerr magnetometer for the analysis of nanostructured materials.

    Science.gov (United States)

    Teixeira, J M; Lusche, R; Ventura, J; Fermento, R; Carpinteiro, F; Araujo, J P; Sousa, J B; Cardoso, S; Freitas, P P

    2011-04-01

    Magneto-optical Kerr effect (MOKE) magnetometry is an indispensable, reliable, and one of the most widely used techniques for the characterization of nanostructured magnetic materials. Information, such as the magnitude of coercive fields or anisotropy strengths, can be readily obtained from MOKE measurements. We present a description of our state-of-the-art vectorial MOKE magnetometer, being an extremely versatile, accurate, and sensitivity unit with a low cost and comparatively simple setup. The unit includes focusing lenses and an automatized stepper motor stage for angular dependent measurements. The performance of the magnetometer is demonstrated by hysteresis loops of Co thin films displaying uniaxial anisotropy induced on growth, MnIr/CoFe structures exhibiting the so called exchange bias effect, spin valves, and microfabricated flux guides produced by optical lithography. © 2011 American Institute of Physics

  14. Feasibility study of a sup 3 He-magnetometer for neutron electric dipole moment experiments

    CERN Document Server

    Borisov, Y; Leduc, M; Lobashev, V; Otten, E W; Sobolev, Y

    2000-01-01

    We report on a sup 3 He-magnetometer capable of detecting tiny magnetic field fluctuations of less than 10 sup - sup 1 sup 4 T in experiments for measuring the electric dipole moment (EDM) of the neutron. It is based on the Ramsey technique of separated oscillating fields and uses nuclear spin-polarized sup 3 He gas which is stored in two vessels of V approx =10 l in a sandwich-type arrangement around the storage bottle for ultra-cold neutrons (UCN). The gas is polarized by means of optical pumping in a separate, small discharge cell at pressures around 0.5 mbar and is then expanded into the actual magnetometer volume. To detect the polarization of sup 3 He gas at the end of the storage cycle the gas is pumped out by means of an oil-diffusion pump and compressed again into the discharge cell where optical detection of nuclear polarization is used.

  15. Magnetocardiography measurements with 4He vector optically pumped magnetometers at room temperature

    Science.gov (United States)

    Morales, S.; Corsi, M. C.; Fourcault, W.; Bertrand, F.; Cauffet, G.; Gobbo, C.; Alcouffe, F.; Lenouvel, F.; Le Prado, M.; Berger, F.; Vanzetto, G.; Labyt, E.

    2017-09-01

    In this paper, we present a proof of concept study which demonstrates for the first time the possibility of recording magnetocardiography (MCG) signals with 4He vector optically pumped magnetometers (OPM) operated in a gradiometer mode. Resulting from a compromise between sensitivity, size and operability in a clinical environment, the developed magnetometers are based on the parametric resonance of helium in a zero magnetic field. Sensors are operated at room temperature and provide a tri-axis vector measurement of the magnetic field. Measured sensitivity is around 210 f T (√Hz)-1 in the bandwidth (2 Hz; 300 Hz). MCG signals from a phantom and two healthy subjects are successfully recorded. Human MCG data obtained with the OPMs are compared to reference electrocardiogram recordings: similar heart rates, shapes of the main patterns of the cardiac cycle (P/T waves, QRS complex) and QRS widths are obtained with both techniques.

  16. Synthesis and properties of Pr-substituted MgZn ferrites for core materials and high frequency applications

    Energy Technology Data Exchange (ETDEWEB)

    Mukhtar, Muhammad Waqas; Irfan, Muhammad [Department of Physics, Federal Urdu University of Arts, Science and Technology, Islamabad 44000 (Pakistan); Ahmad, Ishtiaq; Ali, Ihsan [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Akhtar, Majid Niaz [Department of Physics, COMSATS Institute of Information Technology, Lahore (Pakistan); Khan, Muhammad Azhar [Department of Physics, Islamia University, Bahawalpur (Pakistan); Abbas, Ghazanfar [Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan); Rana, M.U. [Center of Excellence in Solid State Physics, University of the Punjab, Lahore (Pakistan); Ali, Akbar [Department of Basic Sciences, Riphah International University, Islamabad-44000 (Pakistan); Ahmad, Mukhtar, E-mail: ahmadmr25@yahoo.com [Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)

    2015-05-01

    A series of single phase spinel ferrites having chemical formula Mg{sub 0.5}Zn{sub 0.5}Pr{sub x}Fe{sub 2−x}O{sub 4} (x=0.00, 0.05, 0.10, 0.15, 0.20, 0.25) were prepared using the sol–gel technique after sintering at 700 °C. The thermal decomposition behavior of an as prepared powder was investigated by means of DTA/TGA analyses. The sintered powders were then characterized by Fourier transform infrared spectroscope, X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscope and vibrating sample magnetometer. X-ray diffraction patterns confirm the single phase spinel structure of prepared ferrites without the presence of any impurity phase. The value of lattice parameter (a) increases with the increase of Pr contents (x) into the spinel lattice. The grain size estimated from electron microscope images is in the range of 2.75–5.4 µm which confirms the spinel crystalline nature of the investigated samples. The saturation magnetization (M{sub s}) decreases whereas coercivity (H{sub c}) increases with the increase of Pr contents (x). The measured parameters suggest that these materials are favorable for high frequency applications and as core materials. - Highlights: • Pr-substituted spinel ferrites synthesized by autocombustion route have been investigated. • The average grain size was in the range of 2.75–5.4 µm estimated by SEM technique. • The (M{sub s}) decreases whereas (H{sub c}) increases with the increase of Pr contents (x). • These parameters are favorable for high frequency applications and as core materials.

  17. Identification of Mobile Phones Using the Built-In Magnetometers Stimulated by Motion Patterns.

    Science.gov (United States)

    Baldini, Gianmarco; Dimc, Franc; Kamnik, Roman; Steri, Gary; Giuliani, Raimondo; Gentile, Claudio

    2017-04-06

    We investigate the identification of mobile phones through their built-in magnetometers. These electronic components have started to be widely deployed in mass market phones in recent years, and they can be exploited to uniquely identify mobile phones due their physical differences, which appear in the digital output generated by them. This is similar to approaches reported in the literature for other components of the mobile phone, including the digital camera, the microphones or their RF transmission components. In this paper, the identification is performed through an inexpensive device made up of a platform that rotates the mobile phone under test and a fixed magnet positioned on the edge of the rotating platform. When the mobile phone passes in front of the fixed magnet, the built-in magnetometer is stimulated, and its digital output is recorded and analyzed. For each mobile phone, the experiment is repeated over six different days to ensure consistency in the results. A total of 10 phones of different brands and models or of the same model were used in our experiment. The digital output from the magnetometers is synchronized and correlated, and statistical features are extracted to generate a fingerprint of the built-in magnetometer and, consequently, of the mobile phone. A SVM machine learning algorithm is used to classify the mobile phones on the basis of the extracted statistical features. Our results show that inter-model classification (i.e., different models and brands classification) is possible with great accuracy, but intra-model (i.e., phones with different serial numbers and same model) classification is more challenging, the resulting accuracy being just slightly above random choice.

  18. Accelerometer and Magnetometer Based Gyroscope Emulation on Smart Sensor for a Virtual Reality Application

    Directory of Open Access Journals (Sweden)

    Baptiste Delporte

    2012-03-01

    Full Text Available In this paper, we propose two methods based on quaternions to compute the angles of inclination and the angular velocity with 6 degrees of freedom using the measurements of a 3-axis accelerometer and a 3-axis magnetometer. Each method has singularities which occur during the computation of the orientation of the device in the 3-dimensional space. We propose solutions to avoid these singularities. Experimental results are given to compare our model with a real gyroscope.

  19. Magnetometer instrument team studies for the definition phase of the outer planets grand tour

    Science.gov (United States)

    Coleman, P. J., Jr.

    1973-01-01

    The work performed by the magnetic fields investigation team during the mission definition phases of the Outer Planets Grand Tour (OPGT) and the Mariner Jupiter Saturn (MJS) Missions is reported. This work involved three tasks: (1) defining the objectives of the magnetic fields investigations, (2) defining the magnetometer systems required to meet these objectives, and (3) developing and testing hardware elements in certain mission-specific areas.

  20. Application of Overhauser DNP and K optics INTERMAGNET quantum magnetometers to fundamental physics and cosmology

    Directory of Open Access Journals (Sweden)

    Sapunov V.A., Rasson J., Sergeev A.V., Narkhov E.D., Denisov A.Y., Rubinstein B.Y., Sapunov A.V.

    2016-12-01

    Full Text Available This article provides suggestions and ideas on the use of magnetic observatories to observe the stability of the gyromagnetic ratio of the proton and the electron in order to detect the effects of new fundamental physics and cosmology. The idea consist in long continuous recording of the signals Overhauser and optical pumping K magnetometers. Such systems can be highly effective network for forecasting earthquakes due to highest long term sensitivity.

  1. New vector/scalar Overhauser DNP magnetometers POS-4 for magnetic observatories and directional oil drilling support

    Directory of Open Access Journals (Sweden)

    Sapunov V.A., Denisov A.Y., Saveliev D.V., Soloviev A.A., Khomutov S.Y., Borodin P.B., Narkhov E.D., Sergeev A.V., Shirokov A.N.

    2016-12-01

    Full Text Available This paper covers same results of the research directed at developing an absolute vector proton magnetometer POS-4 based on the switching bias magnetic fields methods. Due to the high absolute precision and stability magnetometer POS-4 found application not only for observatories and to directional drilling support of oi and gas well. Also we discuss the some basic errors of measurements and discuss the long-term experience in the testing of magnetic observatories ART and PARATUNKA.

  2. Uniform magnetic core/shell microspheres functionalized with Ni2+-iminodiacetic acid for one step purification and immobilization of his-tagged enzymes.

    Science.gov (United States)

    Zhang, Yuting; Yang, Yongkun; Ma, Wanfu; Guo, Jia; Lin, Yao; Wang, Changchun

    2013-04-10

    A facile approach has been developed to synthesize Fe3O4/PMG (poly (N,N'-methylenebisacrylamide-co-glycidyl methacrylate)) core/shell microspheres using distillation-precipitation polymerization. Treating PMG shell with iminodiacetic acid (IDA) and Ni2+ yields composite microspheres of Fe3O4/PMG/IDA-Ni2+. The Ni2+ ions loaded on the surface of microspheres provide abundant docking sites for immobilization of histidine-tagged proteins. The high saturation magnetization of Fe3O4/PMG (23 emu/g), determined by vibrating sample magnetometer (VSM), allows an easy separation of the microspheres from solution under an external magnetic field. The composite microspheres were used to purify two His-tagged cellulolytic enzymes (Cel48F and Cel9G) directly from crude cell lysates with high binding affinity, capacity, and specificity. The microspheres can be recycled for many times without significant loss of binding capacity to enzymes. The immobilized enzymes on the surface of microspheres well retain their biological activities in degradation of cellulose. These materials show great potential in the biomedical and biotechnological applications that require low-cost purification of recombinant proteins and instant enzyme immobilization at an industrial scale.

  3. An unshielded radio-frequency atomic magnetometer with sub-femtoTesla sensitivity

    Directory of Open Access Journals (Sweden)

    David A. Keder

    2014-12-01

    Full Text Available We demonstrate a radio-frequency potassium-vapor magnetometer operating with sensitivities of 0.3 fT/ Hz at 0.5 MHz and 0.9 fT/ Hz at 1.31 MHz in the absence of radio-frequency and mu-metal or magnetic shielding. The use of spatially separated magnetometers, two voxels within the same cell, permits for the subtraction of common mode noise and the retention of a gradient signal, as from a local source. At 0.5 MHz the common mode noise was white and measured to be 3.4 fT/ Hz ; upon subtraction the noise returned to the values observed when the magnetometer was shielded. At 1.31 MHz, the common mode noise was from a nearby radio station and was reduced by a factor of 33 upon subtraction, limited only by the radio signal picked up by receiver electronics. Potential applications include in-the-field low-field magnetic resonance, such as the use of nuclear quadrupole resonance for the detection of explosives.

  4. Attitude Determination with Magnetometers and Accelerometers to Use in Satellite Simulator

    Directory of Open Access Journals (Sweden)

    Helio Koiti Kuga

    2013-01-01

    Full Text Available Attitude control of artificial satellites is dependent on information provided by its attitude determination process. This paper presents the implementation and tests of a fully self-contained algorithm for the attitude determination using magnetometers and accelerometers, for application on a satellite simulator based on frictionless air bearing tables. However, it is known that magnetometers and accelerometers need to be calibrated so as to allow that measurements are used to their ultimate accuracy. A calibration method is implemented which proves to be essential for improving attitude determination accuracy. For the stepwise real-time attitude determination, it was used the well-known QUEST algorithm which yields quick response with reduced computer resources. The algorithms are tested and qualified with actual data collected on the streets under controlled situations. For such street runaways, the experiment employs a solid-state magnetoresistive magnetometer and an IMU navigation block consisting of triads of accelerometers and gyros, with MEMS technology. A GPS receiver is used to record positional information. The collected measurements are processed through the developed algorithms, and comparisons are made for attitude determination using calibrated and noncalibrated data. The results show that the attitude accuracy reaches the requirements for real-time operation for satellite simulator platforms.

  5. An Optically Pumped Magnetometer Working in the Light-Shift Dispersed Mz Mode.

    Science.gov (United States)

    Schultze, Volkmar; Schillig, Bastian; IJsselsteijn, Rob; Scholtes, Theo; Woetzel, Stefan; Stolz, Ronny

    2017-03-10

    We present an optically pumped magnetometer working in a new operational mode-the light-shift dispersed Mz (LSD-Mz) mode. It is realized combining various features; (1) high power off-resonant optical pumping; (2) Mz configuration, where pumping light and magnetic field of interest are oriented parallel to each other; (3) use of small alkali metal vapor cells of identical properties in integrated array structures, where two such cells are pumped by circularly polarized light of opposite helicity; and (4) subtraction of the Mz signals of these two cells. The LSD-Mz magnetometer's performance depends on the inherent and very complex interplay of input parameters. In order to find the configuration of optimal magnetometer resolution, a sensitivity analysis of the input parameters by means of Latin Hypercube Sampling was carried out. The resulting datasets of the multi-dimensional parameter space exploration were assessed by a subsequent physically reasonable interpretation. Finally, the best shot-noise limited magnetic field resolution was determined within that parameter space. As the result, using two 50 mm3 integrated vapor cells a magnetic field resolution below 10 fT/√Hz at Earth's magnetic field strength is possible.

  6. Combined spacecraft orbit and attitude control through extended Kalman filtering of magnetometer, gyro, and GPS measurements

    Directory of Open Access Journals (Sweden)

    Tamer Mekky Ahmed Habib

    2014-06-01

    Full Text Available The main goal of this research is to establish spacecraft orbit and attitude control algorithms based on extended Kalman filter which provides estimates of spacecraft orbital and attitude states. The control and estimation algorithms must be capable of dealing with the spacecraft conditions during the detumbling and attitude acquisition modes of operation. These conditions are characterized by nonlinearities represented by large initial attitude angles, large initial angular velocities, large initial attitude estimation error, and large initial position estimation error. All of the developed estimation and control algorithms are suitable for application to the next Egyptian scientific satellite, EGYPTSAT-2. The parameters of the case-study spacecraft are similar but not identical to the former Egyptian satellite EGYPTSAT-1. This is done because the parameters of EGYPTSAT-2 satellite have not been consolidated yet. The sensors utilized are gyro, magnetometer, and GPS. Gyro and magnetometer are utilized to provide measurements for the estimates of spacecraft attitude state vector where as magnetometer and GPS are utilized to provide measurements for the estimates of spacecraft orbital state vector.

  7. A Test Of Cpt And Lorentz Symmetry Using A Potassium- Helium-3 Co-magnetometer

    CERN Document Server

    Kornack, T W

    2005-01-01

    A K-3He co-magnetometer has been developed for a test of Lorentz and CPT symmetry. Polarized K vapor forms a spin-exchange relaxation-free (SERF) magnetometer that has record sensitivity of about 1 fT/ Hz . The polarized 3He effectively suppresses sensitivity to the magnetic fields and gradients. Together, the K-3He co-magnetometer retains sensitivity to anomalous, CPT- and Lorentz- violating fields that couple to electron and nuclear spins differently than a normal magnetic field. Data over the course of 15 months provide upper limits on the coupling energy of a CPT-violating field to neutron spin, b˜n < 1.4 × 10−31 GeV, to proton spin, b˜p < 4.4 × 10−30 GeV, and to electron spin, b˜e < 1.0 × 10−28 GeV. These limits are consistent with the existing limits of b˜n < 1.1 × 10−31 GeV (Bear et al., 2002) and b˜ e < 3.0 × 10−29 Ge...

  8. MgB{sub 2} magnetometer with a directly coupled pick-up loop

    Energy Technology Data Exchange (ETDEWEB)

    Portesi, C [Istituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, I-10135 Turin (Italy); Mijatovic, D [Low Temperature Division and Mesa Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Veldhuis, D [Low Temperature Division and Mesa Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Brinkman, A [Low Temperature Division and Mesa Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Monticone, E [Istituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, I-10135 Turin (Italy); Gonnelli, R S [INFM, Dipartimento di Fisica, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Turin (Italy)

    2006-05-15

    In this work, we show the results obtained in the fabrication and characterization of an MgB{sub 2} magnetometer with a directly coupled pick-up loop. We used an all in situ technique for fabricating magnesium diboride films, which consists of the co-evaporation of B and Mg by means of an e-gun and a resistive heater respectively. Consequently, we realized the superconducting device, which incorporates two nanobridges as weak links in a superconducting loop. The nanobridges were realized by focused ion beam milling; they were 240 nm wide and had a critical current density of 10{sup 7} A cm{sup -2}. The magnetometer was characterized at different temperatures and also measurements of the noise levels have been performed. The device shows Josephson quantum interference up to 20 K and the calculated effective area at low temperatures was 0.24 mm{sup 2}. The transport properties of the magnetometer allow determining fundamental materials properties of the MgB{sub 2} thin films, such as the penetration depth.

  9. The MAGIC of CINEMA: first in-flight science results from a miniaturised anisotropic magnetoresistive magnetometer

    Directory of Open Access Journals (Sweden)

    M. O. Archer

    2015-06-01

    Full Text Available We present the first in-flight results from a novel miniaturised anisotropic magnetoresistive space magnetometer, MAGIC (MAGnetometer from Imperial College, aboard the first CINEMA (CubeSat for Ions, Neutrals, Electrons and MAgnetic fields spacecraft in low Earth orbit. An attitude-independent calibration technique is detailed using the International Geomagnetic Reference Field (IGRF, which is temperature dependent in the case of the outboard sensor. We show that the sensors accurately measure the expected absolute field to within 2% in attitude mode and 1% in science mode. Using a simple method we are able to estimate the spacecraft's attitude using the magnetometer only, thus characterising CINEMA's spin, precession and nutation. Finally, we show that the outboard sensor is capable of detecting transient physical signals with amplitudes of ~ 20–60 nT. These include field-aligned currents at the auroral oval, qualitatively similar to previous observations, which agree in location with measurements from the DMSP (Defense Meteorological Satellite Program and POES (Polar-orbiting Operational Environmental Satellites spacecraft. Thus, we demonstrate and discuss the potential science capabilities of the MAGIC instrument onboard a CubeSat platform.

  10. Measurement Sensitivity Improvement of All-Optical Atomic Spin Magnetometer by Suppressing Noises

    Directory of Open Access Journals (Sweden)

    Xiyuan Chen

    2016-06-01

    Full Text Available Quantum manipulation technology and photoelectric detection technology have jointly facilitated the rapid development of ultra-sensitive atomic spin magnetometers. To improve the output signal and sensitivity of the spin-exchange-relaxation-free (SERF atomic spin magnetometer, the noises influencing on the output signal and the sensitivity were analyzed, and the corresponding noise suppression methods were presented. The magnetic field noises, including the residual magnetic field noise and the light shift noise, were reduced to approximately zero by employing the magnetic field compensation method and by adjusting the frequency of the pump beam, respectively. With respect to the operation temperature, the simulation results showed that the temperature of the potassium atomic spin magnetometer realizing the spin-exchange relaxation-free regime was 180 °C. Moreover, the fluctuation noises of the frequency and the power were suppressed by using the frequency and the power stable systems. The experimental power stability results showed that the light intensity stability was enhanced 10%. Contrast experiments on the sensitivity were carried out to demonstrate the validity of the suppression methods. Finally, a sensitivity of 13 fT/Hz1/2 was successfully achieved by suppressing noises and optimizing parameters.

  11. The MAGIC of CINEMA: first in-flight science results from a miniaturised anisotropic magnetoresistive magnetometer

    Science.gov (United States)

    Archer, M. O.; Horbury, T. S.; Brown, P.; Eastwood, J. P.; Oddy, T. M.; Whiteside, B. J.; Sample, J. G.

    2015-06-01

    We present the first in-flight results from a novel miniaturised anisotropic magnetoresistive space magnetometer, MAGIC (MAGnetometer from Imperial College), aboard the first CINEMA (CubeSat for Ions, Neutrals, Electrons and MAgnetic fields) spacecraft in low Earth orbit. An attitude-independent calibration technique is detailed using the International Geomagnetic Reference Field (IGRF), which is temperature dependent in the case of the outboard sensor. We show that the sensors accurately measure the expected absolute field to within 2% in attitude mode and 1% in science mode. Using a simple method we are able to estimate the spacecraft's attitude using the magnetometer only, thus characterising CINEMA's spin, precession and nutation. Finally, we show that the outboard sensor is capable of detecting transient physical signals with amplitudes of ~ 20-60 nT. These include field-aligned currents at the auroral oval, qualitatively similar to previous observations, which agree in location with measurements from the DMSP (Defense Meteorological Satellite Program) and POES (Polar-orbiting Operational Environmental Satellites) spacecraft. Thus, we demonstrate and discuss the potential science capabilities of the MAGIC instrument onboard a CubeSat platform.

  12. Research on evaluation method for water saturation of tight sandstone in Suxi region

    Science.gov (United States)

    Lv, Hong; Lai, Fuqiang; Chen, Liang; Li, Chao; Li, Jie; Yi, Heping

    2017-05-01

    The evaluation of irreducible water saturation is important for qualitative and quantitative prediction of residual oil distribution. However, it is to be improved for the accuracy of experimental measuring the irreducible water saturation and logging evaluation. In this paper, firstly the multi-functional core flooding experiment and the nuclear magnetic resonance centrifugation experiment are carried out in the west of Sulige gas field. Then, the influence was discussed about particle size, porosity and permeability on the water saturation. Finally, the evaluation model was established about irreducible water saturation and the evaluation of irreducible water saturation was carried out. The results show that the results of two experiments are both reliable. It is inversely proportional to the median particle size, porosity and permeability, and is most affected by the median particle size. The water saturation of the dry layer is higher than that of the general reservoir. The worse the reservoir property, the greater the water saturation. The test results show that the irreducible water saturation model can be used to evaluate the water floor.

  13. The QuakeFinder Magnetometer Network - a Platform for Earth and Space Science Research

    Science.gov (United States)

    Bleier, T.; Kappler, K. N.; Schneider, D.

    2016-12-01

    QuakeFinder (QF) is a humanitarian research and development project attempting to characterize earth-emitting electromagnetic (EM) signals as potential precursors to earthquakes. Beginning in 2005, QF designed, built, deployed and now maintains an array of 165 remote monitoring stations in 6 countries (US/California, Taiwan, Greece, Indonesia, Peru and Chile). Having amassed approximately 70 TB of data and greater than 140 earthquakes (M4+), QF is focused on the data analysis and signal processing algorithms in our effort to enable a forecasting capability. QF's autonomous stations, located along major fault lines, collect and transmit electromagnetic readings from 3-axis induction magnetometers and positive/negative ion sensors, a geophone, as well as various station health status and local conditions. The induction magnetometers, oriented N-S,E-W and vertically, have a 40 nT range and 1 pT sensitivity. Data is continuously collected at 50 samples/sec (sps), GPS time-stamped and transmitted, primarily through cell phone networks, to our data center in Palo Alto, California. The induction magnetometers routinely detect subtle geomagnetic and ionospheric disturbances as observed worldwide. QF seeks to make available both historic data and the array platform to strategic partners in the EM-related research and operation fields. The QF system will be described in detail with examples of local and regional geomagnetic activity. The stations are robust and will be undergoing a system-level upgrade in the near future. Domestically, QF maintains a 98% `up time' among the 120 stations in California while internationally our metric is typically near 80%. Irregular cell phone reception is chief among the reasons for outages although little data has been lost as the stations can store up to 90 days of data. These data are retrieved by QF personnel or, when communication is reestablished, the QF data ingest process automatically updates the database. Planned station upgrades

  14. Using X-ray computed tomography to evaluate the initial saturation resulting from different saturation procedures

    DEFF Research Database (Denmark)

    Christensen, Britt Stenhøj Baun; Wildenschild, D; Jensen, K.H.

    2006-01-01

    for saturation. Evaluation of the different enhanced saturation techniques was done with Xray computed tomography (CT) and gravimetrically. The use of CT scanning makes it possible to observe the spatial distribution of wetting and non-wetting phases in the porous medium in a non-destructive way. In this case...... with pressurized nitrogen between each saturation and allowed to saturate for the same length of time for all the different procedures. Both gravimetric measurements and CT attenuation levels showed that venting the sample with carbon dioxide prior to saturation clearly improved initial saturation whereas the use...

  15. Synthesis and characterization of saturated polyester and ...

    Indian Academy of Sciences (India)

    and nanocomposites derived from glycolyzed PET waste with varied compositions. SUNAIN KATOCH. ∗ ... Water vapour transmission (WVT) was determined for saturated polyester nanocomposite sheets according to ... ing the synthesis of saturated polyester (from GPET waste). This has been done for the estimation of the ...

  16. Ultrafast THz Saturable Absorption in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate THz saturable absorption in n-doped semiconductors GaAs, GaP, and Ge in a nonlinear THz time-domain spectroscopy experiment. Saturable absorption is caused by sample conductivity modulation due to electron heating and satellite valley scattering in the field of a strong THz pulse....

  17. Fault tolerant control of systems with saturations

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2013-01-01

    This paper presents framework for fault tolerant controllers (FTC) that includes input saturation. The controller architecture known from FTC is based on the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization is extended to handle input saturation. Applying this controller architecture in connec...

  18. Semiconductor saturable absorbers for ultrafast terahertz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    We demonstrate saturable absorber behavior of n-type semiconductors GaAs, GaP, and Ge in the terahertz THz frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum...

  19. Thermohydraulic design of saturated temperature capsule for IASCC irradiation test

    Energy Technology Data Exchange (ETDEWEB)

    Ide, Hiroshi; Matsui, Yoshinori; Itabashi, Yukio [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment] [and others

    2002-10-01

    An advanced water chemistry controlled irradiation research device is being developed in JAERI, to perform irradiation tests for irradiation assisted stress corrosion cracking (IASCC) research concerned with aging of LWR. This device enables the irradiation tests under the water chemistry condition and the temperature, which simulate the conditions for BWR core internals. The advanced water chemistry controlled irradiation research device is composed of saturated temperature capsule inserted into the JMTR core and the water chemistry control unit installed in the reactor building. Regarding the saturated temperature capsule, the Thermohydraulic design of capsule structure was done, aimed at controlling the specimen's temperature, feeding water velocity on specimen's surface to the environment of BWR nearer. As the result of adopting the new capsule structure based on the design study, it was found out that feeding water velocity at the surface of specimen's is increased to about 10 times as much as before, and nuclear heat generated in the capsule components can be removed safely even in the abnormal event such as the case of loss of feeding water. (author)

  20. Determination of saturation functions and wettability for chalk based on measured fluid saturations

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, D.; Bech, N.; Moeller Nielsen, C.

    1998-08-01

    The end effect of displacement experiments on low permeable porous media is used for determination of relative permeability functions and capillary pressure functions. Saturation functions for a drainage process are determined from a primary drainage experiment. A reversal of the flooding direction creates an intrinsic imbibition process in the sample, which enables determination if imbibition saturation functions. The saturation functions are determined by a parameter estimation technique. Scanning effects are modelled by the method of Killough. Saturation profiles are determined by NMR. (au)

  1. Nuclear magnetic resonance and sound velocity measurements of chalk saturated with magnesium rich brine

    DEFF Research Database (Denmark)

    Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    2013-01-01

    composition. In this study we relate NMR data to changes in P-wave velocity and electrical resistivity. Core plugs from outcrop Stevns chalk, of 44% porosity, were divided into groups of three and saturated with deionized water, calcite equilibrated water, as well as sodium chloride and magnesium chloride...

  2. Design, Analysis and Simulation of Magnetic Biased Inductors with Saturation-Gap

    DEFF Research Database (Denmark)

    Aguilar, Andres Revilla; Munk-Nielsen, Stig

    2014-01-01

    Permanent magnet biasing, is a known technique for increasing the energy storage capability of inductors operating in DC applications. The opposing flux introduced by a permanent magnet will extend the saturation flux limit of a given magnetic material. When full biasing of the core is achieved...

  3. Size Reduction of a DC Link Choke Using Saturation Gap and Biasing with Permanent Magnets

    DEFF Research Database (Denmark)

    Aguilar, Andres Revilla; Munk-Nielsen, Stig; Zuccherato, Marco

    2014-01-01

    This document describes the design procedure of permanent magnet biased DC inductors using the Saturation-gap technique [1]. This biasing configuration can provide a 50% reduction in either the core volume or the number of turns, while meeting its current and inductance requirements. A design exa...

  4. Mode instability in a Yb-doped stretched core fiber

    Science.gov (United States)

    Xia, N.; Yoo, S.

    2017-02-01

    In this work we present the theoretical study of transverse mode instability (TMI) in ytterbium (Yb)-doped rectangular core fibers with different core aspect ratios using the fast Fourier transform (FFT) beam propagation method (BPM). As expected, the rectangular core fiber with larger aspect ratio (AR.) offers more efficient heat dissipation than a circular core fiber. However, it is found that the rectangular core fiber does not benefit from the better heat dissipation to suppress the TMI when compared to the circular core counterpart. The temperature building in the rectangular core fiber decreases by up to 24.6% with a 10:1 aspect ratio core, while threshold pump power drops by up to 38.3% when compared with a circular core fiber with the same core area. Our study reveals that a smaller effective refractive index difference between modes and a weaker gain saturation effect compensate the thermal advantage from more efficient heat dissipation.

  5. Unscented KALMAN Filtering for Spacecraft Attitude and Rate Determination Using Magnetometer

    Directory of Open Access Journals (Sweden)

    Sung-Woo Kim

    2009-03-01

    Full Text Available An Unscented Kalman Filter (UKF for estimation of the attitude and rate of a spacecraft using only magnetometer vector measurement is developed. The attitude dynamics used in the estimation is the nonlinear Euler`s rotational equation which is augmented with the quaternion kinematics to construct a process model. The filter is designed for small satellite in low Earth orbit, so the disturbance torques include gravity-gradient torque, magnetic disturbance torque, and aerodynamic drag torque. The magnetometer measurements are simulated based on time-varying position of the spacecraft. The filter has been tested not only in the standby mode but also in the detumbling mode. Two types of actuators have been modeled and applied in the simulation. The PD controller is used for the two types of actuators (reaction wheels and thrusters to detumble the spacecraft. The estimation error converged to within 5 deg for attitude and 0.1 deg/s for rate respectively when the two types of actuators were used. A joint state parameter estimation has been tested and the effect of the process noise covariance on the parameter estimation has been indicated. Also, Monte-Carlo simulations have been performed to test the capability of the filter to converge with the initial conditions sampled from a uniform distribution. Finally, the UKF performance has been compared to that of the EKF and it demonstrates that UKF slightly outperforms EKF. The developed algorithm can be applied to any type of small satellites that are actuated by magnetic torquers, reaction wheels or thrusters with a capability of magnetometer vector measurements for attitude and rate estimation.

  6. Experience of 1-second magnetometer LEMI-025 use in the INTERMAGNET observatories

    Science.gov (United States)

    Marusenkov, Andriy

    2014-05-01

    More than ten years ago INTERMAGNET community decided to commence producing filtered one-second data in addition to traditional one-minute data, hourly, daily, monthly, and annual means. This decision was inspired by the increasing demand of space physics scientists, investigating wave processes in the ionosphere and the magnetosphere of the Earth's. The first requirements for a geomagnetic data acquisition system capable to acquire 1-second data were compiled during the INTERMAGNET survey, conducted by Jeffrey Love in 2005, investigating the needs of the scientific community using geomagnetic time series data. The main consensus of the survey is as follows: geomagnetic data acquired at 1 Hz sampling should have 0.01 nT resolution at least, be filtered by a digital filter and be centred onto the UTC second within 0.01 s. Besides, the one-second magnetometer has to have much lower noise than that of 1-minute one, because the natural geomagnetic signals rapidly decay at the higher frequencies. And finally, the one-second instrument has to provide a sufficient level of immunity to manmade (industrial) noise, especially as produced by power lines. In order to meet these partly conflicting requirements to the frequency response, a new magnetometer functional diagram, which combines analogue and digital filters, was proposed in the Lviv Centre of Institute for Space Research. Basing on this approach the first model LEMI-025 was designed, built, successfully tested and installed in Dourbes geomagnetic observatory (Belgium) since 2008. Later, after considerable modifications, these first commercially available instruments compatible with one-second INTERMAGNET standard were installed in a number of geomagnetic observatories over the Globe. The experience of LEMI-025 operation during the past few years let us evaluate the baseline stability of the new one-second magnetometer (factors accuracy and stability (transfer function (<0.005 %). More details on this topic will be

  7. Fluxgate Magnetometer system mounted on UAS system: First field test at Dominga IOCG deposit, Chile

    Science.gov (United States)

    Yanez, G. A.; Banchero, L.; Marco, A.; Figueroa, R.

    2016-12-01

    With the support of Fundacion Chile (FCH) grant, we developed an airborne magnetic system (GeoMagDrone GFDAS) mounted on a UAS octodrone platform (DJI, S1000), based on a low cost/light-weight fluxgate magnetometer (FGM-301) and a robust/light-weight data logger for position, temperature, radar altimeter and 3 magnetic components at 16 Hz recording. Fluxgate magnetometer is hanging from the UAS platform at a distance of 2.5m where the EM noise is reduced to less than 2 nT. The whole geophysical system, including batteries, weights 650 gr., with an autonomy of 2 hours. Magnetometer calibration includes the 9 coefficients of amplitude, offset, and orthogonality, and temperature correction. We test the system over the IOCG deposit of Dominga-Chile, a magnetite ore (40%) (a block of 2x3 km with NS lines separated every 50m and a clearance of 40m, the mineral deposit buried 50-100m from the surface, where a ground magnetic survey was conducted previously. Ground conditions includes relatively rough topography with slopes of 10-20%, and some windy days. We use the digital terrain model SRTM30 to define the drape flight shape Average flight performance includes a mean speed of 35-40 km/hour, and an UAS battery consumption of 18-12 minutes depending on the wind conditions. A good correspondence was found between plan deployment and survey results in terms of line direction/separation/clearance. Line path were flown with errors less than 5 meters, whereas clearance of 40m was kept depending on the amount of control points used. The comparison between ground survey and GeoMagDrone results show a perfect match (anomaly amplitude/shape and noise envelope), validating in this way the system developed. Main concern for the productive application of this technology in unmanned geophysical platforms is the battery performance and the quality of digital terrain models to follow the topography.

  8. Rb atomic magnetometer toward EDM experiment with laser cooled francium atoms

    Science.gov (United States)

    Inoue, Takeshi; Ando, Shun; Aoki, Takahiro; Arikawa, Hiroshi; Harada, Ken-Ichi; Hayamizu, Tomohiro; Ishikawa, Taisuke; Itoh, Masatoshi; Kato, Ko; Kawamura, Hirokazu; Sakamoto, Kosuke; Uchiyama, Aiko; Asahi, Koichiro; Yoshimi, Akihiro; Sakemi, Yasuhiro

    2014-09-01

    A permanent electric dipole moment (EDM) of a particle or an atom is a suited observable to test the physics beyond the standard model. We plan to search for the electron EDM by using the laser cooled francium (Fr) atom, since the Fr atom has a large enhancement factor of the electron EDM and the laser cooling techniques can suppress both statistical and systematic errors. In the EDM experiment, a fluctuation of the magnetic field is a main source of the errors. In order to achieve the high precision magnetometry, a magnetometer based on the nonlinear magneto-optical rotation effect of the Rb atom is under development. A long coherence time of Rb atom is the key issue for the highly sensitive detection of the field fluctuations. The coherence time is limited due both to collisions with an inner surface of a cell contained the Rb atom and to residual field in a magnetic shield. We prepared the cell coated with an anti-relaxation material and measured the relaxation time. A degauss of the shield was performed to eliminate the residual field. We will report the present status of the magnetometer. A permanent electric dipole moment (EDM) of a particle or an atom is a suited observable to test the physics beyond the standard model. We plan to search for the electron EDM by using the laser cooled francium (Fr) atom, since the Fr atom has a large enhancement factor of the electron EDM and the laser cooling techniques can suppress both statistical and systematic errors. In the EDM experiment, a fluctuation of the magnetic field is a main source of the errors. In order to achieve the high precision magnetometry, a magnetometer based on the nonlinear magneto-optical rotation effect of the Rb atom is under development. A long coherence time of Rb atom is the key issue for the highly sensitive detection of the field fluctuations. The coherence time is limited due both to collisions with an inner surface of a cell contained the Rb atom and to residual field in a magnetic shield

  9. Searches for Exotic Transient Signals with a Global Network of Optical Magnetometers for Exotic Physics

    CERN Document Server

    Pustelny, S

    2016-01-01

    In this letter, we describe a novel scheme for searching for physics beyond the Standard Model. The idea is based on correlation of time-synchronized readouts of distant ($\\gtrsim$100~km) optical magnetometers. Such an approach limits hard-to-identify local transient noise, providing the system with unique capabilities of identification of global transient events. Careful analysis of the signal can reveal the nature of the events (e.g., its nonmagnetic origin), which opens avenues for new class of exotic-physics searches (searches for global transient exotic spin couplings) and tests of yet unverified theoretical models.

  10. Ultra-low-field NMR relaxation and diffusion measurements using an optical magnetometer.

    Science.gov (United States)

    Ganssle, Paul J; Shin, Hyun D; Seltzer, Scott J; Bajaj, Vikram S; Ledbetter, Micah P; Budker, Dmitry; Knappe, Svenja; Kitching, John; Pines, Alexander

    2014-09-08

    Nuclear magnetic resonance (NMR) relaxometry and diffusometry are important tools for the characterization of heterogeneous materials and porous media, with applications including medical imaging, food characterization and oil-well logging. These methods can be extremely effective in applications where high-resolution NMR is either unnecessary, impractical, or both, as is the case in the emerging field of portable chemical characterization. Here, we present a proof-of-concept experiment demonstrating the use of high-sensitivity optical magnetometers as detectors for ultra-low-field NMR relaxation and diffusion measurements. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Analysis of magnetometer data/wave signals in the Earth's magnetosphere

    Science.gov (United States)

    Engebretson, Mark J.

    1993-01-01

    Work on the reduction and analysis of Dynamics Explorer (DE) satellite magnetometer data with special emphasis on the ULF fluctuations and waves evident in such data is described. Research focused on the following: (1) studies of Pc 1 wave packets near the plasmapause; (2) satellite-ground pulsation study; (3) support for studies of ion energization processes; (4) search for Pc 1 wave events in 1981 DE 1 data; (5) study of Pc 3-5 events observed simultaneously by DE 1 and by AMPTE CCE; (6) support for studies of electromagnetic transients on DE 1; and (7) analysis of wave events induced by sudden impulses.

  12. An atomic magnetometer with autonomous frequency stabilization and large dynamic range

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, S., E-mail: spradhan@barc.gov.in, E-mail: pradhans75@gmail.com; Poornima,; Dasgupta, K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 85 (India); Homi Bhabha National Institute, Department of Atomic Energy, Mumbai 85 (India); Mishra, S.; Behera, R. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 85 (India)

    2015-06-15

    The operation of a highly sensitive atomic magnetometer using elliptically polarized resonant light is demonstrated. It is based on measurement of zero magnetic field resonance in degenerate two level systems using polarimetric detection. The transmitted light through the polarimeter is used for laser frequency stabilization, whereas reflected light is used for magnetic field measurement. Thus, the experimental geometry allows autonomous frequency stabilization of the laser frequency leading to compact operation of the overall device and has a preliminary sensitivity of <10 pT/Hz{sup 1/2} @ 1 Hz. Additionally, the dynamic range of the device is improved by feedback controlling the bias magnetic field without compromising on its sensitivity.

  13. The analysis of initial Juno magnetometer data using a sparse magnetic field representation

    DEFF Research Database (Denmark)

    Moore, Kimberly M.; Bloxham, Jeremy; Connerney, John E. P.

    2017-01-01

    The Juno spacecraft, now in polar orbit about Jupiter, passes much closer to Jupiter's surface than any previous spacecraft, presenting a unique opportunity to study the largest and most accessible planetary dynamo in the solar system. Here we present an analysis of magnetometer observations from...... Juno's first perijove pass (PJ1; to within 1.06 RJ of Jupiter's center). We calculate the residuals between the vector magnetic field observations and that calculated using the VIP4 spherical harmonic model and fit these residuals using an elastic net regression. The resulting model demonstrates how...

  14. Is light narrowing possible with dense-vapor paraffin coated cells for atomic magnetometers?

    Science.gov (United States)

    Han, Runqi; Balabas, Mikhail; Hovde, Chris; Li, Wenhao; Roig, Hector Masia; Wang, Tao; Wickenbrock, Arne; Zhivun, Elena; You, Zheng; Budker, Dmitry

    2017-12-01

    We investigated the operation of an all-optical rubidium-87 atomic magnetometer with amplitude-modulated light. To study the suppression of spin-exchange relaxation, three schemes of pumping were implemented with room-temperature and heated paraffin coated vacuum cells. Efficient pumping and accumulation of atoms in the F=2 ground state were obtained. However, the sought-for narrowing of the resonance lines has not been achieved. A theoretical analysis of the polarization degree is presented to illustrate the absence of light narrowing due to radiation trapping at high temperature.

  15. Magnetocardiographic Data Using Squid Magnetometer And Its Movie Display By Means Of Spline Function

    Science.gov (United States)

    Funakubo, Noboru; Koga, Seiki

    1984-08-01

    At present electrocardiogram has been most developped in the area of heart diagnosis. But at the surface of body there is also the magnetic field which is induced from electromotive forces in the muscles of heart. This magnetic field has attracted doctor's considerable interest recently, and it is called magnetocardiogram(MCGD. In this paper, a method which we used for measuring the MCG data using a superconducting quantum interference device magnetometer is firstly explained. Next, in order to be able to evaluate the data more easily for doctor they are made into a movie using image processing by computer, then its contents and the result are presented.

  16. Feasibility Study for an Autonomous UAV -Magnetometer System -- Final Report on SERDP SEED 1509:2206

    Energy Technology Data Exchange (ETDEWEB)

    Roelof Versteeg; Mark McKay; Matt Anderson; Ross Johnson; Bob Selfridge; Jay Bennett

    2007-09-01

    Large areas across the United States are potentially contaminated with UXO, with some ranges encompassing tens to hundreds of thousands of acres. Technologies are needed which will allow for cost effective wide area scanning with 1) near 100 % coverage and 2) near 100 % detection of subsurface ordnance or features indicative of subsurface ordnance. The current approach to wide area scanning is a multi-level one, in which medium altitude fixed wing optical imaging is used for an initial site assessment. This assessment is followed with low altitude manned helicopter based magnetometry followed by surface investigations using either towed geophysical sensor arrays or man portable sensors. In order to be effective for small UXO detection, the sensing altitude for magnetic site investigations needs to be on the order of 1 – 3 meters. These altitude requirements means that manned helicopter surveys will generally only be feasible in large, open and relatively flat terrains. While such surveys are effective in mapping large areas relatively fast there are substantial mobilization/demobilization, staffing and equipment costs associated with these surveys (resulting in costs of approximately $100-$150/acre). Surface towed arrays provide high resolution maps but have other limitations, e.g. in their ability to navigate rough terrain effectively. Thus, other systems are needed allowing for effective data collection. An UAV (Unmanned Aerial Vehicle) magnetometer platform is an obvious alternative. The motivation behind such a system is that it would be safer for the operators, cheaper in initial and O&M costs, and more effective in terms of site characterization. However, while UAV data acquisition from fixed wing platforms for large (> 200 feet) stand off distances is relatively straight forward, a host of challenges exist for low stand-off distance (~ 6 feet) UAV geophysical data acquisition. The objective of SERDP SEED 1509:2006 was to identify the primary challenges

  17. netPICOMAG: a low-cost turn-key magnetometer for aurora detection

    Science.gov (United States)

    Schofield, I.; Connors, M.

    2008-12-01

    Previous work on development of a compact, low-cost, fluxgate magnetometer, dubbed PICOMAG, yielded a 1-nanotesla resolution, 1-second cadence instrument, suitable for research or teaching solar/terrestrial physics. With a low-cost magnetic instrument and the wider availability of Internet connectivity in the auroral zone (of Canada for example), the potential exists to fill gaps in spatial coverage that still plague auroral geomagnetic research. Thus, the ability to widely distribute accurate, low cost magnetometers was the motivating factor to develop PICOMAG. NetPICOMAG was developed in the effort to refine PICOMAG into a turn-key magnetometer data collection system that is self contained, simple to install and requires zero-maintenance. Once the unit is placed in the ground and connected to the Internet, it locks onto a GPS time signal and begins to transmit magnetic field measurements back to a central data repository, where it is archived, processed and plotted for public viewing via the World Wide Web. It is envisaged (among many other uses) that science teachers can use real scientific data provided by netPICOMAG in teaching the interactions between the sun and the Earth's magnetic field, manifesting itself in the phenomenon known as the northern lights. As such, netPICOMAG can be aptly described and is being promoted as an aurora detector. The netPICOMAG unit is based around three spatially oriented Speake and Company FGM-3/3h series magnetic field sensors that each emit a pulse stream whose frequency is related to the magnetic field along these three axes, and is nearly linearly related to magnetic field perturbations relevant to auroral studies. The individual pulse frequencies are measured by two PIC18F252 programmable microcontrollers. The measurements are combined with a GPS timestamp from a Garmin GPS 18 LVC GPS receiver, and transmitted as plain text as UDP datagrams by a Rabbit Semiconductor RCM4010 8-bit, networked microcontroller module. The self

  18. A 70 kV solid-state high voltage pulse generator based on saturable pulse transformer.

    Science.gov (United States)

    Fan, Xuliang; Liu, Jinliang

    2014-02-01

    High voltage pulse generators are widely applied in many fields. In recent years, solid-state and operating at repetitive mode are the most important developing trends of high voltage pulse generators. A solid-state high voltage pulse generator based on saturable pulse transformer is proposed in this paper. The proposed generator is consisted of three parts. They are charging system, triggering system, and the major loop. Saturable pulse transformer is the key component of the whole generator, which acts as a step-up transformer and main switch during working process of this generator. The circuit and working principles of the proposed pulse generator are introduced first in this paper, and the saturable pulse transformer used in this generator is introduced in detail. Circuit of the major loop is simulated to verify the design of the system. Demonstration experiments are carried out, and the results show that when the primary energy storage capacitor is charged to a high voltage, such as 2.5 kV, a voltage with amplitude of 86 kV can be achieved on the secondary winding. The magnetic core of saturable pulse transformer is saturated deeply and the saturable inductance of the secondary windings is very small. The switch function of the saturable pulse transformer can be realized ideally. Therefore, a 71 kV output voltage pulse is formed on the load. Moreover, the magnetic core of the saturable pulse transformer can be reset automatically.

  19. Combinatorics of saturated secondary structures of RNA.

    Science.gov (United States)

    Clote, P

    2006-11-01

    Following Zuker (1986), a saturated secondary structure for a given RNA sequence is a secondary structure such that no base pair can be added without violating the definition of secondary structure, e.g., without introducing a pseudoknot. In the Nussinov-Jacobson energy model (Nussinov and Jacobson, 1980), where the energy of a secondary structure is -1 times the number of base pairs, saturated secondary structures are local minima in the energy landscape, hence form kinetic traps during the folding process. Here we present recurrence relations and closed form asymptotic limits for combinatorial problems related to the number of saturated secondary structures. In addition, Python source code to compute the number of saturated secondary structures having k base pairs can be found at the web servers link of bioinformatics.bc.edu/clotelab/.

  20. Saturated fat, carbohydrate, and cardiovascular disease

    National Research Council Canada - National Science Library

    Siri-Tarino, Patty W; Sun, Qi; Hu, Frank B; Krauss, Ronald M

    2010-01-01

    A focus of dietary recommendations for cardiovascular disease (CVD) prevention and treatment has been a reduction in saturated fat intake, primarily as a means of lowering LDL-cholesterol concentrations...

  1. Saturated thickness, High Plains aquifer, 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents the saturated thickness of the High Plains aquifer of the United States, 2009, in feet. The High Plains aquifer underlies...

  2. Semiconductor saturable absorbers for ultrafast THz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths.......We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths....

  3. Magnetometer and radar observations of magnetohydrodynamic cavity modes in the Earth's magnetosphere

    Energy Technology Data Exchange (ETDEWEB)

    Samson, J.C. (Alberta Univ., Edmonton, AB (Canada)); Greenwald, R.A.; Ruohoniemi, J.M. (Johns Hopkins Univ., Laurel, MD (USA)); Hughes, T.J.; Wallis, D.D. (National Research Council of Canada, Ottawa, ON (Canada))

    1991-01-01

    Night and early morning data from high frequency radar at Goose Bay, Labrador, and from the magnetometers in the Canadian CANOPUS array often show structured spectra with distinct spectral peaks at 1.3, 1.9, and 2.6 mHz. These frequencies are very stable and vary by less than {plus minus}5% for the 6 days of data that have been analyzed. The radar measurements of the F-region drift velocities indicate that these spectral peaks are often associated with field line resonances of the shear Alfven wave, and that the resonances are seen at lower latitudes as the frequency increases. The magnetometer data indicate that the magnetohydrodynamic (MHD) waves have westward phase velocities. It is shown that these observations are compatible with the formation of MHD cavity modes in the early morning and nightside magnetosphere, between the magnetopause, at approximately 14.5 earth radii, and turning points in the dipolar magnetosphere, outside the plasmasphere. Likely sources of energy are compressional pulses from the solar wind or Kelvin-Helmholtz instabilities in the low-latitude boundary layer. 22 refs., 13 figs., 3 tabs.

  4. Counter electrojet features in the Brazilian sector: simultaneous observation by radar, digital sounder and magnetometers

    Directory of Open Access Journals (Sweden)

    C. M. Denardini

    2009-04-01

    Full Text Available In the present work we show new results regarding equatorial counter electrojet (CEJ events in the Brazilian sector, based on the RESCO radar, two set of fluxgate magnetometer systems and a digital sounder. RESCO radar is a 50 MHz backscatter coherent radar installed in 1998 at São Luís (SLZ, 2.33° S, 44.60° W, an equatorial site. The Digital sounder routinely monitors the electron density profile at the radar site. The magnetometer systems are fluxgate-type installed at SLZ and Eusébio (EUS, 03.89° S, 38.44° W. From the difference between the horizontal component of magnetic field at SLZ station and the same component at EUS (EEJ ground strength several cases of westward morning electrojet and its normal inversion to the eastward equatorial electrojet (EEJ have been observed. Also, the EEJ ground strength has shown some cases of CEJ events, which been detected with the RESCO radar too. Detection of these events were investigated with respect to their time and height of occurrence, correlation with sporadic E (Es layers at the same time, and their spectral characteristics as well as the radar echo power intensity.

  5. An Optically Pumped Magnetometer Working in the Light-Shift Dispersed Mz Mode

    Directory of Open Access Journals (Sweden)

    Volkmar Schultze

    2017-03-01

    Full Text Available We present an optically pumped magnetometer working in a new operational mode—the light-shift dispersed Mz (LSD-Mz mode. It is realized combining various features; (1 high power off-resonant optical pumping; (2 Mz configuration, where pumping light and magnetic field of interest are oriented parallel to each other; (3 use of small alkali metal vapor cells of identical properties in integrated array structures, where two such cells are pumped by circularly polarized light of opposite helicity; and (4 subtraction of the Mz signals of these two cells. The LSD-Mz magnetometer’s performance depends on the inherent and very complex interplay of input parameters. In order to find the configuration of optimal magnetometer resolution, a sensitivity analysis of the input parameters by means of Latin Hypercube Sampling was carried out. The resulting datasets of the multi-dimensional parameter space exploration were assessed by a subsequent physically reasonable interpretation. Finally, the best shot-noise limited magnetic field resolution was determined within that parameter space. As the result, using two 50 mm3 integrated vapor cells a magnetic field resolution below 10 fT/√Hz at Earth’s magnetic field strength is possible.

  6. Calibration of QM-MOURA three-axis magnetometer and gradiometer

    Science.gov (United States)

    Díaz-Michelena, M.; Sanz, R.; Cerdán, M. F.; Fernández, A. B.

    2015-01-01

    MOURA instrument is a three-axis magnetometer and gradiometer designed and developed for Mars MetNet Precursor mission. The initial scientific goal of the instrument is to measure the local magnetic field in the surroundings of the lander i.e. to characterize the magnetic environment generated by the remanent magnetization of the crust and the superimposed daily variations of the field produced either by the solar wind incidence or by the thermomagnetic variations. Therefore, the qualification model (QM) will be tested in representative scenarios like magnetic surveys on terrestrial analogues of Mars and monitoring solar events, with the aim to achieve some experience prior to the arrival to Mars. In this work, we present a practical first approach for calibration of the instrument in the laboratory; a finer correction after the comparison of MOURA data with those of a reference magnetometer located in San Pablo de los Montes (SPT) INTERMAGNET Observatory; and a comparative recording of a geomagnetic storm as a demonstration of the compliance of the instrument capabilities with the scientific objectives.

  7. Demonstration of the SeptiStrand benthic microbial fuel cell powering a magnetometer for ship detection

    Science.gov (United States)

    Arias-Thode, Y. Meriah; Hsu, Lewis; Anderson, Greg; Babauta, Jerome; Fransham, Roy; Obraztsova, Anna; Tukeman, Gabriel; Chadwick, D. Bart

    2017-07-01

    The Navy has a need for monitoring conditions and gathering information in marine environments. Sensors can monitor and report environmental parameters and potential activities such as animal movements, ships, or personnel. However, there has to be a means to power these sensors. One promising enabling technology that has been shown to provide long-term power production in underwater environments is the benthic microbial fuel cells (BMFC). BMFCs are devices that generate energy by coupling bioanodes and biocathodes through an external energy harvester. Recent studies have demonstrated success for usage of BMFCs in powering small instruments and other devices on the seafloor over limited periods of time. In this effort, a seven-stranded BMFC linear array of 30 m was designed to power a seafloor magnetometer to detect passing ship movements through Pearl Harbor, Hawaii. The BMFC system was connected to a flyback energy harvesting circuit that charged the battery powering the magnetometer. The deployment was demonstrated the BMFC supplied power to the battery for approximately 38 days. This is the first large-scale demonstration system for usage of the SeptiStrand BMFC technology to power a relevant sensor.

  8. Real-time estimation of projectile roll angle using magnetometers: in-lab experimental validation

    Science.gov (United States)

    Changey, S.; Pecheur, E.; Wey, P.; Sommer, E.

    2013-12-01

    The knowledge of the roll angle of a projectile is decisive to apply guidance and control law. For example, the goal of ISL's project GSP (Guided Supersonic Projectile) is to change the flight path of an airdefence projectile in order to correct the aim error due to the target manoeuvres. The originality of the concept is based on pyrotechnical actuators and onboard sensors which control the angular motion of the projectile. First of all, the control of the actuators requires the precise control of the roll angle of the projectile. To estimate the roll angle of the projectile, two magnetometers are embedded in the projectile to measure the projection of the Earth magnetic field along radial axes of the projectiles. Then, an extended Kalman filter (EKF) is used to compute the roll angle estimation. As the rolling frequency of the GSP is about 22 Hz, it was easy to test the navigation algorithm in laboratory. In a previous paper [1], the In-Lab demonstration of this concept showed that the roll angle estimation was possible with an accuracy of about 1◦ . In this paper, the demonstration is extended to high-speed roll rate, up to 1000 Hz. Thus, two magnetometers, a DSP (Digital Signal Processor) and a LED (Light Eminent Diode), are rotated using a pneumatic motor; the DSP runs an EKF and a guidance algorithm to compute the trigger times of the LED. By using a high-speed camera, the accuracy of the method can be observed and improved.

  9. Integrating a High Resolution Optically Pumped Magnetometer with a Multi-Rotor UAV towards 3-D Magnetic Gradiometry

    Science.gov (United States)

    Braun, A.; Walter, C. A.; Parvar, K.

    2016-12-01

    The current platforms for collecting magnetic data include dense coverage, but low resolution traditional airborne surveys, and high resolution, but low coverage terrestrial surveys. Both platforms leave a critical observation gap between the ground surface and approximately 100m above ground elevation, which can be navigated efficiently by new technologies, such as Unmanned Aerial Vehicles (UAVs). Specifically, multi rotor UAV platforms provide the ability to sense the magnetic field in a full 3-D tensor, which increases the quality of data collected over other current platform types. Payload requirements and target requirements must be balanced to fully exploit the 3-D magnetic tensor. This study outlines the integration of a GEM Systems Cesium Vapour UAV Magnetometer, a Lightware SF-11 Laser Altimeter and a uBlox EVK-7P GPS module with a DJI s900 Multi Rotor UAV. The Cesium Magnetometer is suspended beneath the UAV platform by a cable of varying length. A set of surveys was carried out to optimize the sensor orientation, sensor cable length beneath the UAV and data collection methods of the GEM Systems Cesium Vapour UAV Magnetometer when mounted on the DJI s900. The target for these surveys is a 12 inch steam pipeline located approximately 2 feet below the ground surface. A systematic variation of cable length, sensor orientation and inclination was conducted. The data collected from the UAV magnetometer was compared to a terrestrial survey conducted with the GEM GST-19 Proton Procession Magnetometer at the same elevation, which also served a reference station. This allowed for a cross examination between the UAV system and a proven industry standard for magnetic field data collection. The surveys resulted in optimizing the above parameters based on minimizing instrument error and ensuring reliable data acquisition. The results demonstrate that optimizing the UAV magnetometer survey can yield to industry standard measurements.

  10. Error Analysis of High Frequency Core Loss Measurement for Low-Permeability Low-Loss Magnetic Cores

    DEFF Research Database (Denmark)

    Niroumand, Farideh Javidi; Nymand, Morten

    2016-01-01

    in magnetic cores is B-H loop measurement where two windings are placed on the core under test. However, this method is highly vulnerable to phase shift error, especially for low-permeability, low-loss cores. Due to soft saturation and very low core loss, low-permeability low-loss magnetic cores are favorable...... in many of the high-efficiency high power-density power converters. Magnetic powder cores, among the low-permeability low-loss cores, are very attractive since they possess lower magnetic losses in compared to gapped ferrites. This paper presents an analytical study of the phase shift error in the core....... The analysis has been validated by experimental measurements for relatively low-loss magnetic cores with different permeability values....

  11. Impact of Reservoir Fluid Saturation on Seismic Parameters: Endrod Gas Field, Hungary

    Science.gov (United States)

    El Sayed, Abdel Moktader A.; El Sayed, Nahla A.

    2017-12-01

    Outlining the reservoir fluid types and saturation is the main object of the present research work. 37 core samples were collected from three different gas bearing zones in the Endrod gas field in Hungary. These samples are belonging to the Miocene and the Upper - Lower Pliocene. These samples were prepared and laboratory measurements were conducted. Compression and shear wave velocity were measured using the Sonic Viewer-170-OYO. The sonic velocities were measured at the frequencies of 63 and 33 kHz for compressional and shear wave respectively. All samples were subjected to complete petrophysical investigations. Sonic velocities and mechanical parameters such as young’s modulus, rigidity, and bulk modulus were measured when samples were saturated by 100%-75%-0% brine water. Several plots have been performed to show the relationship between seismic parameters and saturation percentages. Robust relationships were obtained, showing the impact of fluid saturation on seismic parameters. Seismic velocity, Poisson’s ratio, bulk modulus and rigidity prove to be applicable during hydrocarbon exploration or production stages. Relationships among the measured seismic parameters in gas/water fully and partially saturated samples are useful to outline the fluid type and saturation percentage especially in gas/water transitional zones.

  12. Influence of the Saturation Ratio on Concrete Behavior under Triaxial Compressive Loading

    Directory of Open Access Journals (Sweden)

    Xuan-Dung Vu

    2015-01-01

    Full Text Available When a concrete structure is subjected to an impact, the material is subjected to high triaxial compressive stresses. Furthermore, the water saturation ratio in massive concrete structures may reach nearly 100% at the core, whereas the material dries quickly on the skin. The impact response of a massive concrete wall may thus depend on the state of water saturation in the material. This paper presents some triaxial tests performed at a maximum confining pressure of 600 MPa on concrete representative of a nuclear power plant containment building. Experimental results show the concrete constitutive behavior and its dependence on the water saturation ratio. It is observed that as the degree of saturation increases, a decrease in the volumetric strains as well as in the shear strength is observed. The coupled PRM constitutive model does not accurately reproduce the response of concrete specimens observed during the test. The differences between experimental and numerical results can be explained by both the influence of the saturation state of concrete and the effect of deviatoric stresses, which are not accurately taken into account. The PRM model was modified in order to improve the numerical prediction of concrete behavior under high stresses at various saturation states.

  13. Saturated fats and cardiovascular disease risk: A review

    OpenAIRE

    Ishi Khosla; Gayatri C Khosla1

    2017-01-01

    Saturated fats have been in the line of fire for more than three decades. The major mistake in understanding fats was to equate all saturated fatty acids as one. The oversimplification of the relationship of saturated fats with cardiovascular disease (CVD) led to unwarranted removal of some valuable fats from our diets. Recently, the relationship of dietary saturated fats and that of individual saturated fatty acids (SFAs) to CVD risk has been reevaluated. All saturated fats are not equal and...

  14. Results of neutron irradiation of liquid lithium saturated with deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Tazhibayeva, Irina, E-mail: tazhibayeva@ntsc.kz [Institute of Atomic Energy, National Nuclear Center of RK, Kurchatov (Kazakhstan); Ponkratov, Yuriy; Kulsartov, Timur; Gordienko, Yuriy; Skakov, Mazhyn; Zaurbekova, Zhanna [Institute of Atomic Energy, National Nuclear Center of RK, Kurchatov (Kazakhstan); Lyublinski, Igor [JSC «Red Star», Moscow (Russian Federation); NRNU «MEPhI», Moscow (Russian Federation); Vertkov, Alexey [JSC «Red Star», Moscow (Russian Federation); Mazzitelli, Giuseppe [ENEA, RC Frascati, Frascati (Italy)

    2017-04-15

    Highlights: • The results on neutron irradiation of liquid lithium saturated with deuterium at the IVG.1M research reactor are described. • At temperatures below 573 K the efficiency coefficient of tritium release is well described by the expression K = 0.015 exp(−14/RT), and above 623 K − K = 10{sup 9} exp(−144/RT). • The T{sub 2} molecules contribution into the overall tritium release becomes apparent at temperatures higher than 673 K and increases with the temperature rise. - Abstract: This paper describes the results on neutron irradiation of liquid lithium saturated with deuterium at the IVG.1 M research reactor. The neutron flux at the reactor core center at 2 MW was 5 10{sup −13} cm{sup −2} s{sup −1}. The efficiency coefficients of helium and tritium release from lithium saturated with deuterium were calculated. The tritium interaction with lithium atoms (formation and dissociation of lithium tritide) has an effect on tritium release. An increment of sample’s temperature results in tritium release acceleration due to rising of the dissociation rate of lithium tritide. At temperatures below 573 K the efficiency coefficient of tritium release is well described by the expression K = 0.015 exp(−14/RT), and above 623 K − K = 10{sup 9} exp(-144/RT). The T{sub 2} molecules contribution into the overall tritium release becomes apparent at temperatures higher than 673 K and increases with the temperature rise.

  15. Current and Noise Saturation in Graphene Superlattice

    Science.gov (United States)

    Yang, Wei; Lu, Xiaobo; Berthou, Simon; Wilmart, Quentin; Boukhicha, Mohamed; Voisin, Christophe; Zhang, Guangyu; Placais, Bernard

    One of the merits of graphene is that the Fermi level can be easily tuned by electrical gating, which render charge carriers n type or p type, or even insulating around the Dirac point (DP). By aligning graphene on top of Boron Nitride (BN), the presence of graphene superlattice makes transport properties even more versatile owning to the emergence of secondary Dirac points (SDPs). Here we present a study of high electric field performance of graphene superlattice obtained from epitaxial approach. By using microwave cavity, noise produced from graphene by joule heating is recorded up to 5GHz. Current and noise saturation are observed and investigated. Depending on Fermi energy, saturation can be attributed to intrinsic optical or remote surface polar phonon scattering at a doping far away from DP, while no saturation are found around DP. Moreover, noise saturation is identified around Fermi energy between DP and SDP, which can be attributed to the influence of van Hove singularity arising from the superlattice. Lastly, saturation due to the bias induced shift of DP, or so called Dirac fermion pinch-off, is well observed by local top gate technique. EU Graphene flagship project (Contract No. 604391).

  16. Integrated induction coil and fluxgate magnetometers for EM analysis and monitoring

    Science.gov (United States)

    Hanstein, T.; Strack, K.; Jiang, J.

    2013-12-01

    The concept of a full field array electromagnetic system is an ideal tool to support hydrocarbon and geothermal E & P as well as various engineering monitoring applications. Some of the key questions are defining the reservoir, mapping of the fractures and reservoir depletion monitoring. The reservoirs are all too often relative thin and give an anomalous electromagnetic (EM) response, which is often small in amplitude and challenging for the EM measuring system. A digital fluxgate magnetometer (32-bit) is connected to the KMS magnetotelluric acquisition system with analogue induction coils and electrodes to extend the range of application of a single recording site. Since the noise level is above that of the induction coil for periods shorter than 20 s, the apparent resistivity is biased. For longer periods the apparent resistivity is consistent and eventually better than the induction coil. However, phase and tipper are not biased and agree well with the induction data even for shorter periods. This allows us to develop algorithms that significantly extend the range of application of the fluxgate beyond what was done in the past. The highest frequency of the fluxgate magnetometer is about 180 Hz and the hightest sampling of the FG-board is 4 kHz.The different induction coils and fluxgate magnetometer have intensively been tested in the magnetic chamber and at the field test site near Houston for noise performance by parallel recordings. They show that even in an environment with high cultural noise, the specification can be met. In Northeast China, a 30-day monitoring test with MT was carried out for seismologic applications. Acquisitition schedule included different recordings times and sampling rates. Daily, the data was collected and processed via the internet from either Europe or the US. Even with long recording, we still had to select the time windows for data averaging and coherences are not a good threshhold criteria in this case. During another MT

  17. Lipid order, saturation and surface property relationships: a study of human meibum saturation.

    Science.gov (United States)

    Mudgil, Poonam; Borchman, Douglas; Yappert, Marta C; Duran, Diana; Cox, Gregory W; Smith, Ryan J; Bhola, Rahul; Dennis, Gary R; Whitehall, John S

    2013-11-01

    Tear film stability decreases with age however the cause(s) of the instability are speculative. Perhaps the more saturated meibum from infants may contribute to tear film stability. The meibum lipid phase transition temperature and lipid hydrocarbon chain order at physiological temperature (33 °C) decrease with increasing age. It is reasonable that stronger lipid-lipid interactions could stabilize the tear film since these interactions must be broken for tear break up to occur. In this study, meibum from a pool of adult donors was saturated catalytically. The influence of saturation on meibum hydrocarbon chain order was determined by infrared spectroscopy. Meibum is in an anhydrous state in the meibomian glands and on the surface of the eyelid. The influence of saturation on the surface properties of meibum was determined using Langmuir trough technology. Saturation of native human meibum did not change the minimum or maximum values of hydrocarbon chain order so at temperatures far above or below the phase transition of human meibum, saturation does not play a role in ordering or disordering the lipid hydrocarbon chains. Saturation did increase the phase transition temperature in human meibum by over 20 °C, a relatively high amount. Surface pressure-area studies showing the late take off and higher maximum surface pressure of saturated meibum compared to native meibum suggest that the saturated meibum film is quite molecularly ordered (stiff molecular arrangement) and elastic (molecules are able to rearrange during compression and expansion) compared with native meibum films which are more fluid agreeing with the infrared spectroscopic results of this study. In saturated meibum, the formation of compacted ordered islands of lipids above the surfactant layer would be expected to decrease the rate of evaporation compared to fluid and more loosely packed native meibum. Higher surface pressure observed with films of saturated meibum compared to native meibum

  18. MOURA magnetometer for Mars MetNet Precursor Mission. Its potential for an in situ magnetic environment and surface characterization

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Michelena, M.; Sanz, R.; Fernandez, A.B.; Manuel, V. de; Cerdan, M.F.; Apestigue, V.; Arruego, I.; Azcue, J.; Dominguez, J.A.; Gonzalez, M.; Guerrero, H.; Sabau, M.; Kilian, R.; Baeza, O.; Ros, F.; Vazquez, M.; Tordesillas, J.M.; Covisa, P.; Aguado, J.

    2016-07-01

    MOURA magnetometer and gradiometer is part of the scientific instrumentation for Mars MetNet Precursor mission. This work describes the objective of the investigation, summarizes the work done in the design and development of the sensor as well as its calibration, and shows the demonstration campaigns to show the potential of such instrument for planetary landers and rovers. (Author)

  19. Soil Structure and Saturated Hydraulic Conductivity

    Science.gov (United States)

    Houskova, B.; Nagy, V.

    The role of soil structure on saturated hydraulic conductivity changes is studied in plough layers of texturally different soils. Three localities in western part of Slovakia in Zitny ostrov (Corn Island) were under investigation: locality Kalinkovo with light Calcaric Fluvisol (FAO 1970), Macov with medium heavy Calcari-mollic Fluvisol and Jurova with heavy Calcari-mollic Fluvisol. Soil structure was determined in dry as well as wet state and in size of macro and micro aggregates. Saturated hydraulic conductivity was measured by the help of double ring method. During the period of ring filling the soil surface was protected against aggregates damage by falling water drops. Spatial and temporal variability of studied parameters was evaluated. Cultivated crops were ensilage maize at medium heavy and heavy soil and colza at light soil. Textural composition of soil and actual water content at the beginning of measurement are one of major factor affecting aggregate stability and consequently also saturated hydraulic conductivity.

  20. Perturbative Saturation and the Soft Pomeron

    CERN Document Server

    Kovner, A; Kovner, Alex; Wiedemann, Urs Achim

    2002-01-01

    We show that perturbation theory provides two distinct mechanisms for the power like growth of hadronic cross sections at high energy. One, the leading BFKL effect is due to the growth of the parton density, and is characterized by the leading BFKL exponent. The other mechanism is due to the infrared diffusion, or the long range nature of the Coulomb field of perturbatively massless gluons. When perturbative saturation effects are taken into account, the first mechanism is rendered ineffective but the second one persists. We suggest that these two distinct mechanisms are responsible for the appearance of two pomerons. The density growth effects are responsible for the hard pomeron and manifest themselves in small systems (e.g. gamma^* or small size fluctuations in the proton wave function) where saturation effects are not important. The soft pomeron is the manifestation of the exponential growth of the black saturated regions which appear in typical hadronic systems. We point out that the nonlinear generaliza...

  1. Interger multiplication with overflow detection or saturation

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, M.J.; Balzola, P.I.; Akkas, A.; Brocato, R.W.

    2000-01-11

    High-speed multiplication is frequently used in general-purpose and application-specific computer systems. These systems often support integer multiplication, where two n-bit integers are multiplied to produce a 2n-bit product. To prevent growth in word length, processors typically return the n least significant bits of the product and a flag that indicates whether or not overflow has occurred. Alternatively, some processors saturate results that overflow to the most positive or most negative representable number. This paper presents efficient methods for performing unsigned or two's complement integer multiplication with overflow detection or saturation. These methods have significantly less area and delay than conventional methods for integer multiplication with overflow detection and saturation.

  2. The Danish tax on saturated fat

    DEFF Research Database (Denmark)

    Vallgårda, Signild; Holm, Lotte; Jensen, Jørgen Dejgård

    2015-01-01

    BACKGROUND/OBJECTIVES: Health promoters have repeatedly proposed using economic policy tools, taxes and subsidies, as a means of changing consumer behaviour. As the first country in the world, Denmark introduced a tax on saturated fat in 2011. It was repealed in 2012. In this paper, we present...... on saturated fat had been suggested by two expert committees and was introduced with a majority in parliament, as a part of a larger economic reform package. Many actors, including representatives from the food industry and nutrition researchers, opposed the tax both before and after its introduction, claiming......, research was published showing that consumption of saturated fat had declined in Denmark. CONCLUSIONS: The analysis indicates that the Danish tax on fat was introduced mainly to increase public revenue. As the tax had no strong proponents and many influential adversaries, it was repealed. New research...

  3. Tracking Controller for Intrinsic Output Saturated Systems in Presence of Amplitude and Rate Input Saturations

    DEFF Research Database (Denmark)

    Chater, E.; Giri, F.; Guerrero, Josep M.

    2014-01-01

    We consider the problem of controlling plants that are subject to multiple saturation constraints. Especially, we are interested in linear systems whose input is subject to amplitude and rate constraints of saturation type. Furthermore, the considered systems output is also subject to an intrinsi...

  4. Femoral venous oxygen saturation is no surrogate for central venous oxygen saturation

    NARCIS (Netherlands)

    van Beest, Paul A.; van der Schors, Alice; Liefers, Henriette; Coenen, Ludo G. J.; Braam, Richard L.; Habib, Najib; Braber, Annemarije; Scheeren, Thomas W. L.; Kuiper, Michael A.; Spronk, Peter E.

    2012-01-01

    Objective:  The purpose of our study was to determine if central venous oxygen saturation and femoral venous oxygen saturation can be used interchangeably during surgery and in critically ill patients. Design:  Prospective observational controlled study. Setting:  Nonacademic university-affiliated

  5. Aeromagnetic Survey by Small Unmanned Aerial Vehicle with Magneto-Resistant Magnetometer at the northern Kalgoorlie area, Western Australia

    Science.gov (United States)

    Funaki, M.; Group, A.; Milligan, P.

    2006-12-01

    We have developed the technology of small drones (unmanned aerial vehicles (UAV)) and an onboard magnetometer focussed on the aeromagnetic surveys under the Ant-Plane project. We succeeded long distant flight to 500km with agnetometer by Ant-Plene4 drone collaborated with Geoscience, Australia, in March 2006. The survey was carried out in the area 10kmx10km around Mt. Vetters Station, Kalgoorlie, West Australian. The magnetic data are obtained from 41 courses (250m in interval) of EW dierction. The altitude of the flight was 900m from sea level and 500m from the runway. The Ant-Plane #4 consists of 2.6m span and 2.0m length with 2-cycles and 2-cylinder 85cc gasoline engine, GPS navigation system by microcomputer and radio telemeter system. The total weight is 25kg including 12.4 litter fuels and the coursing speed is 130. The magnetometer system consists of a 3-component magneto- resistant magnetometer (MR) sensor (Honeywell HMR2300), GPS and data logger. Three components of magnetic field, latitude, longitude, altitude, the number of satellite and time can be recorded in every second during 6 hours. The sensitivity of the magnetometer is 7 nT and we use a total magnetic field intensity for magnetic analysis due to unknown direction of heading of the plane. MR-magnetometer sensor was installed at the tip of a FRP pipe of 1m length, and the pipe was fixed to the head of the plane in order to reduce the plane magnetization. After 4 hours 14 minutes from the takeoff, the 500km flight was accomplished and the magnetic data were obtained from the data logger. The straight flight course was almost consistent with the way point course, but the course was drastically disturbed when the plane was turning. The magnetic noise level during the flight increased to 30nT, when the plane was flight in the tail wind. However, it is much higher when the plane flew in the head wind. The anomaly pattern obtained from Ant-Plane 4 was compared with the magnetic anomaly map published by

  6. Atomic Magnetometer Multisensor Array for rf Interference Mitigation and Unshielded Detection of Nuclear Quadrupole Resonance

    Science.gov (United States)

    Cooper, Robert J.; Prescott, David W.; Matz, Peter; Sauer, Karen L.; Dural, Nezih; Romalis, Michael V.; Foley, Elizabeth L.; Kornack, Thomas W.; Monti, Mark; Okamitsu, Jeffrey

    2016-12-01

    An array of four 87Rb vector magnetometers is used to detect nuclear quadrupole resonance signals in an unshielded environment at 1 MHz. With a baseline of 25 cm, the length of the array, radio-frequency interference mitigation is also demonstrated; a radio-station signal is suppressed by a factor of 20 without degradation to the signal of interest. With these compact sensors, in which the probe beam passes through twice, the fundamental limit to detection sensitivity is found to be photon-shot noise. More passes of the probe beam overcome this limitation. With a sensor of similar effective volume, 0.25 cm3 , but 25 × more passes, the sensitivity is improved by an order of magnitude to 1.7 ±0.2 fT /√{Hz } .

  7. Robust Adaptive Filter for Small Satellite Attitude Estimation Based on Magnetometer and Gyro

    Directory of Open Access Journals (Sweden)

    Zhankui Zeng

    2014-01-01

    Full Text Available Based on magnetometer and gyro measurement, a sequential scheme is proposed to determine the orbit and attitude of small satellite simultaneously. In order to reduce the impact of orbital errors on attitude estimation, a robust adaptive Kalman filter is developed. It uses a scale factor and an adaptive factor, which are constructed by Huber function and innovation sequence, respectively, to adjust the covariance matrix of system state and observational noise, change the weights of predicted and measured parameters, get suitable Kalman filter gain and approximate optimal filtering results. Numerical simulations are carried out and the proposed filter is approved to be robust for the noise disturbance and parameter uncertainty and can provide higher accuracy attitude estimation.

  8. Pc 5 ULF waves observed simultaneously by GOES 7 and the CANOPUS magnetometer array

    Energy Technology Data Exchange (ETDEWEB)

    Ziesolleck, C.W.S.; Feng, Q.; McDiarmid, D.R. [National Research Council of Canada, Ottawa, Ontario (Canada)

    1996-03-01

    The authors have looked at a months worth of data from the CANOPUS magnetometer array (Canadian Auroral Network for the OPEN Program Unified Study) in conjunction with satellite observations from GOES 7 taken in March 1990. Applying filtering techniques they extract Pc 5 type event signatures from this data, and find several events clearly observable in both data sets. The satellite indicated dominantly compressional type events associated with field line resonances. The ground system allows the observation of polarization characteristics, in addition to being able to infer points of origin for the wave events. They then correlate the satellite observations versus relative position from the wave origin. This study shows daily variations in the signals and implies an origin for these compressional waves near local noon.

  9. Nuclear-Spin Gyroscope Based on an Atomic Co-Magnetometer

    Science.gov (United States)

    Romalis, Michael; Komack, Tom; Ghost, Rajat

    2008-01-01

    An experimental nuclear-spin gyroscope is based on an alkali-metal/noblegas co-magnetometer, which automatically cancels the effects of magnetic fields. Whereas the performances of prior nuclear-spin gyroscopes are limited by sensitivity to magnetic fields, this gyroscope is insensitive to magnetic fields and to other external perturbations. In addition, relative to prior nuclear-spin gyroscopes, this one exhibits greater sensitivity to rotation. There is commercial interest in development of small, highly sensitive gyroscopes. The present experimental device could be a prototype for development of nuclear spin gyroscopes suitable for navigation. In comparison with fiber-optic gyroscopes, these gyroscopes would draw less power and would be smaller, lighter, more sensitive, and less costly.

  10. An improved quaternion Gauss–Newton algorithm for attitude determination using magnetometer and accelerometer

    Directory of Open Access Journals (Sweden)

    Liu Fei

    2014-08-01

    Full Text Available For the vector attitude determination, the traditional optimal algorithms which are based on quaternion estimator (QUEST measurement noise model are complicated for just two observations. In our application, the magnetometer and accelerometer are not two comparable kinds of sensors and both are not small field-of-view sensors as well. So in this paper a new unit measurement model is derived. According to the Wahba problem, the optimal weights for each measurement are obtained by the error variance researches. Then an improved quaternion Gauss–Newton method is presented and adopted to acquire attitude. Eventually, simulation results and experimental validation employed to test the proposed method demonstrate the usefulness of the improved algorithm.

  11. Software interface and data acquisition package for the LakeShore cryogenics vibrating sample magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    O`Dell, B.H.

    1995-11-01

    A software package was developed to replace the software provided by LakeShore for their model 7300 vibrating sample magnetometer (VSM). Several problems with the original software`s functionality caused this group to seek a new software package. The new software utilizes many features that were unsupported in the LakeShore software, including a more functional step mode, point averaging mode, vector moment measurements, and calibration for field offset. The developed software interfaces the VSM through a menu driven graphical user interface, and bypasses the VSM`s on board processor leaving control of the VSM up to the software. The source code for this software is readily available to any one. By having the source, the experimentalist has full control of data acquisition and can add routines specific to their experiment.

  12. Magnetic field `flyby' measurement using a smartphone's magnetometer and accelerometer simultaneously

    Science.gov (United States)

    Monteiro, Martín; Stari, Cecilia; Cabeza, Cecilia; Marti, Arturo C.

    2017-12-01

    The spatial dependence of magnetic fields in simple configurations is a common topic in introductory electromagnetism lessons, both in high school and in university courses. In typical experiments, magnetic fields and distances are obtained taking point-by-point values using a Hall sensor and a ruler, respectively. Here, we show how to take advantage of the smartphone capabilities to get simultaneous measures with the built-in accelerometer and magnetometer and to obtain the spatial dependence of magnetic fields. We consider a simple setup consisting of a smartphone mounted on a track whose direction coincides with the axis of a coil. While the smartphone is moving on the track, both the magnetic field and the distance from the center of the coil (integrated numerically from the acceleration values) are simultaneously obtained. This methodology can easily be extended to more complicated setups.

  13. Frequency signal acquisition of scalar atomic magnetometer based on using TDC and FPGA

    Science.gov (United States)

    Ge, Y. H.; Chen, Q. Y.; Zhang, Y. F.; Xia, M. Y.

    2017-09-01

    An improved equal precision frequency measurement method is presented for acquisition of frequency signal output from high sensitivity scalar atomic magnetometers. The frequency range to be measured is from 75 kHz to 350 kHz with a resolution better than 0.01 Hz, and the sampling rate should be at least 10 Hz. To meet the requirements on dynamic range, measurement accuracy and speed, at least eight significant digits must be kept. The TDC and FPGA are used to improve the traditional equal precision method. The FPGA acts as the controlling and computing centre, while the TDC measures the time deviation to eliminate the counting error of ±1 reference signal. A prototype frequency detector is fabricated and tested. The measured data show that the design is viable and further improvement is possible.

  14. Motor Bourn Magnetic Noise Filtering for Magnetometers in Micro-Rotary Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Nathan J. UNWIN

    2015-10-01

    Full Text Available Avionics systems of micro aerial vehicles (MAV pose unique problems in system design, sensor signal handling and control. This is evident in micro-rotary aircraft as their whole body rotates with the sensors of the flight control. The precise calculation of attitude and heading from magnetometer readings is complex due to the body rotation. It is made even more difficult by noise induced in the geomagnetic signal by fluctuating magnetic field of the closely positioned motors. Filtering that noise is challenging since the rotation speed of motors and the vehicle can be very close. This paper presents analysis of motor induced noise, based on experimental data of brushless micro motors. A novel time domain filter is proposed, designed, implemented in FPGA hardware, tested and compared to other filters. This filter provides good performance even when the rotational rate of the motor and vehicle are close and traditional frequency domain filters would perform poorly.

  15. Saturated poroelastic actuators generated by topology optimization

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    2011-01-01

    In this paper the fluid-structure interaction problem of a saturated porous media is considered. The pressure coupling properties of porous saturated materials change with the microstructure and this is utilized in the design of an actuator using a topology optimized porous material. By maximizing...... the coupling of internal fluid pressure and elastic shear stresses a slab of the optimized porous material deflects/deforms when a pressure is imposed and an actuator is created. Several phenomenologically based constraints are imposed in order to get a stable force transmitting actuator....

  16. On the saturation of astrophysical dynamos

    DEFF Research Database (Denmark)

    Dorch, Bertil; Archontis, Vasilis

    2004-01-01

    In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and we study the dynamo's mode of operation during both the linear and non-linear saturation regimes. It turns out that in addition to a high growth rate in the li......In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and we study the dynamo's mode of operation during both the linear and non-linear saturation regimes. It turns out that in addition to a high growth rate...

  17. Site-Scale Saturated Zone Flow Model

    Energy Technology Data Exchange (ETDEWEB)

    G. Zyvoloski

    2003-12-17

    The purpose of this model report is to document the components of the site-scale saturated-zone flow model at Yucca Mountain, Nevada, in accordance with administrative procedure (AP)-SIII.lOQ, ''Models''. This report provides validation and confidence in the flow model that was developed for site recommendation (SR) and will be used to provide flow fields in support of the Total Systems Performance Assessment (TSPA) for the License Application. The output from this report provides the flow model used in the ''Site-Scale Saturated Zone Transport'', MDL-NBS-HS-000010 Rev 01 (BSC 2003 [162419]). The Site-Scale Saturated Zone Transport model then provides output to the SZ Transport Abstraction Model (BSC 2003 [164870]). In particular, the output from the SZ site-scale flow model is used to simulate the groundwater flow pathways and radionuclide transport to the accessible environment for use in the TSPA calculations. Since the development and calibration of the saturated-zone flow model, more data have been gathered for use in model validation and confidence building, including new water-level data from Nye County wells, single- and multiple-well hydraulic testing data, and new hydrochemistry data. In addition, a new hydrogeologic framework model (HFM), which incorporates Nye County wells lithology, also provides geologic data for corroboration and confidence in the flow model. The intended use of this work is to provide a flow model that generates flow fields to simulate radionuclide transport in saturated porous rock and alluvium under natural or forced gradient flow conditions. The flow model simulations are completed using the three-dimensional (3-D), finite-element, flow, heat, and transport computer code, FEHM Version (V) 2.20 (software tracking number (STN): 10086-2.20-00; LANL 2003 [161725]). Concurrently, process-level transport model and methodology for calculating radionuclide transport in the saturated zone at Yucca

  18. Evaluation of structural, morphological and magnetic properties of CuZnNi (CuxZn0.5-xNi0.5Fe2O4) nanocrystalline ferrites for core, switching and MLCI's applications

    Science.gov (United States)

    Akhtar, Majid Niaz; Khan, Muhammad Azhar; Ahmad, Mukhtar; Nazir, M. S.; Imran, M.; Ali, A.; Sattar, A.; Murtaza, G.

    2017-01-01

    The influence of Cu substitution on the structural and morphological characteristics of Ni-Zn nanocrystalline ferrites have been discussed in this work. The detailed and systematic magnetic characterizations were also done for Cu substituted Ni-Zn nanoferrites. The nanocrystalline ferrites of Cu substituted CuxZn0.5-xNi0.5Fe2O4 ferrites (x=0, 0.1, 0.2, 0.3, 0.4 and 0.5) were synthesized using sol gel self-combustion hybrid method. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscope (TEM) and Vibrating sample magnetometer (VSM) were used to investigate the properties of Cu substituted nanocrystalline ferrites. Single phase structure of Cu substituted in Ni-Zn nanocrystalline ferrites were investigated for all the samples. Crystallite size, lattice constant and volume of the cell were found to increase by increasing Cu contents in spinel structure. The better morphology with well-organized nanocrystals of Cu-Zn-Ni ferrites at x=0 and 0.5 were observed from both FESEM and TEM analysis. The average grain size was 35-46 nm for all prepared nanocrystalline samples. Magnetic properties such as coercivity, saturation, remanence, magnetic squareness, magneto crystalline anisotropy constant (K) and Bohr magneton were measured from the recorded M-H loops. The magnetic saturation and remanence were increased by the incorporation of Cu contents. However, coercivity follow the Stoner-Wolforth model except for x=0.3 which may be due to the site occupancy and replacement of Cu contents from octahedral site. The squareness ratio confirmed the super paramgnetic behaviour of the Cu substituted in Ni-Zn nanocrystalline ferrites. Furthermore, Cu substituted Ni-Zn nanocrystalline ferrites may be suitable for many industrial and domestic applications such as components of transformers, core, switching, and MLCI's due to variety of the soft magnetic characteristics.

  19. Study of the Nortern polar ionosphere by all-sky imager, riometer and magnetometer data

    Science.gov (United States)

    Guineva, Veneta; Trondsen, Espen; Marple, Steve; Dahle, Kolbjorn; Stauning, Peter

    The variety of the auroral forms and their behaviour, as a result of the complexity of the processes in the upper atmosphere at high latitudes and the connection between them as well as the large number of influencing factors give a lot of possibilities for new investigations. The opportunity for simultaneous multi-instrument observations by different instruments, as well by sets of instruments of the same kind, nowadays is a precondition for an extensive research of the polar ionosphere phenomena. For this study, simultaneous observations' data of the OI 5577 ´˚ and 6300 ´˚ emissions, the electron precipitation flux and the terrestrial magnetic A A field have been used from the following instruments: the All-Sky Imager (ASI), ALOMAR Imaging Riometer for Ionospheric Studies (AIRIS) and the magnetometer, positioned at Andøya Rocket Range (ARR), Andenes (69.3° N, 16.03° E); ASI, 64-beam Imaging Riometer and the magnetometer at the Auroral Observatory, Longyearbyen, Svalbard (78.20° N, 15.83° E); IRIS at Kilpisj¨rvi, Finland (69.05° N, 20.79° E). The fields of view of the instruments cover a large a area of the auroral oval and the polar cap. The distribution and the behaviour of the optical emissions and the absorption features have been analysed. A good correlation between the spatial and temporal evolutions of the optical emissions, the precipitating electron fluxes and the terrestrial magnetic field has been observed. The response of the ionosphere to the solar and geomagnetic activity changes has been studied. Data access has been provided under the Project "ALOMAR eARI" (RITA-CT-2003-506208), Andenes, Norway. This Project received research funding from the European Community's 6th Framework Program.

  20. What can we tell about global auroral-electrojet activity from a single meridional magnetometer chain?

    Directory of Open Access Journals (Sweden)

    K. Kauristie

    Full Text Available The AE indices are generally used for monitoring the level of magnetic activity in the auroral oval region. In some cases, however, the oval is either so expanded or contracted that the latitudinal coverage of the AE magnetometer chain is not adequate. Then, a longitudinal chain in the key region would give more information of the real situation, but, of course, only during some limited UT-period. In order to find out the UT coverage of a single meridional chain, we have compared the global AL and AU indices with corresponding local indices determined using data from the meridional part of the EISCAT Magnetometer Cross during the years 1985–1987. A statistical study shows that the local indices are close (within relative error of 0.2 to the global AU and AL during periods 1500–2000 UT (~1730–2230 MLT and 2130–0130 UT (~0000–0400 MLT, respectively. In the middle of these optimal MLT-sectors the EISCAT Cross sees more than 70% of the cases when the global AE chain records activity. Then, also the correlation between the local and global indices is generally good (>0.7. Thus we conclude that five to six evenly located meridional chains are needed for covering all the UT-periods. On the other hand, already the combination of IMAGE, CANOPUS, and the Greenland chains catches ~50% of the substorms. Case-studies show that usually during 2130–1100 UT the AL achieved from these chains reproduces the real AL with good timing, although it does not follow all transient variations.

  1. What can we tell about global auroral-electrojet activity from a single meridional magnetometer chain?

    Directory of Open Access Journals (Sweden)

    K. Kauristie

    1996-11-01

    Full Text Available The AE indices are generally used for monitoring the level of magnetic activity in the auroral oval region. In some cases, however, the oval is either so expanded or contracted that the latitudinal coverage of the AE magnetometer chain is not adequate. Then, a longitudinal chain in the key region would give more information of the real situation, but, of course, only during some limited UT-period. In order to find out the UT coverage of a single meridional chain, we have compared the global AL and AU indices with corresponding local indices determined using data from the meridional part of the EISCAT Magnetometer Cross during the years 1985–1987. A statistical study shows that the local indices are close (within relative error of 0.2 to the global AU and AL during periods 1500–2000 UT (~1730–2230 MLT and 2130–0130 UT (~0000–0400 MLT, respectively. In the middle of these optimal MLT-sectors the EISCAT Cross sees more than 70% of the cases when the global AE chain records activity. Then, also the correlation between the local and global indices is generally good (>0.7. Thus we conclude that five to six evenly located meridional chains are needed for covering all the UT-periods. On the other hand, already the combination of IMAGE, CANOPUS, and the Greenland chains catches ~50% of the substorms. Case-studies show that usually during 2130–1100 UT the AL achieved from these chains reproduces the real AL with good timing, although it does not follow all transient variations.

  2. High-sensitivity multifunctional spinner magnetometer using a magneto-impedance sensor

    Science.gov (United States)

    Kodama, Kazuto

    2017-01-01

    A novel spinner magnetometer was developed with a wide dynamic range from 10-10 to 10-4 Am2 and a resolution of 10-11 Am2. High sensitivity was achieved with the use of a magneto-impedance (MI) sensor, which is a compact, sensitive magnetic sensor used industrially. Its slow-spinning rate (5 Hz) and the incorporation of a unique mechanism for adjusting the spacing between the sensing unit and the spinning axis allows the measurement of fragile samples sized 10-50 mm. The sensor configuration, in which a pair of MI sensors is connected in opposite serial, along with an amplification circuit with a programmable low-pass filter, reduces the problems of external noise and sensor drift. The signal, with reference to the spinning frequency, is detected with a lock-in amplifier. The MI spinner has two selectable measurement modes: the fundamental mode (F mode) and the harmonic mode (H mode). Measurements in the F mode detect signals of the fundamental frequency (5 Hz), in the same way as conventional spinner magnetometers. In the H mode, the second (10 Hz) and the third (15 Hz) harmonic components are measured, in addition to the fundamental component. Tests in the H mode were performed using a small coil and a natural sample to simulate dipoles with various degrees of offset. The results revealed that the magnitude of the fundamental component of the offset dipole was systematically larger (by several percent) than that of the nonoffset dipole. These findings suggest that this novel MI spinner will be useful in estimating the inhomogeneity of the magnetization of a sample that can equivalently be described by an offset dipole.

  3. Inverse procedure for high-latitude ionospheric electrodynamics: Analysis of satellite-borne magnetometer data

    Science.gov (United States)

    Matsuo, Tomoko; Knipp, Delores J.; Richmond, Arthur D.; Kilcommons, Liam; Anderson, Brian J.

    2015-06-01

    This paper presents an analysis of data from the magnetometers on board the Defense Meteorological Satellite Program (DMSP) F-15, F-16, F-17, and F-18 satellites and the Iridium satellite constellation, using an inverse procedure for high-latitude ionospheric electrodynamics, during the period of 29-30 May 2010. The Iridium magnetometer data are made available through the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) program. The method presented here is built upon the assimilative mapping of ionospheric electrodynamics procedure but with a more complete treatment of the prior model uncertainty to facilitate an optimal inference of complete polar maps of electrodynamic variables from irregularly distributed observational data. The procedure can provide an objective measure of uncertainty associated with the analysis. The cross-validation analysis, in which the DMSP data are used as independent validation data sets, suggests that the procedure yields the spatial prediction of DMSP perturbation magnetic fields from AMPERE data alone with a median discrepancy of 30-50 nT. Discrepancies larger than 100 nT are seen in about 20% of total samples, whose location and magnitude are generally consistent with the previously identified discrepancy between DMSP and AMPERE data sets. Resulting field-aligned current (FAC) patterns exhibit more distinct spatial patterns without spurious high-frequency oscillatory features in comparison to the FAC products provided by AMPERE. Maps of the toroidal magnetic potential and FAC estimated from both AMPERE and DMSP data under four distinctive interplanetary magnetic field (IMF) conditions during a magnetic cloud event demonstrate the IMF control of high-latitude electrodynamics and the opportunity for future scientific investigation.

  4. Quantum-limited biochemical magnetometers designed using the Fisher information and quantum reaction control

    Science.gov (United States)

    Vitalis, K. M.; Kominis, I. K.

    2017-03-01

    Radical-ion pairs and their reactions have triggered the study of quantum effects in biological systems. This is because they exhibit a number of effects best understood within quantum information science, and at the same time are central in understanding the avian magnetic compass and the spin transport dynamics in photosynthetic reaction centers. Here we address radical-pair reactions from the perspective of quantum metrology. Since the coherent spin motion of radical pairs is effected by an external magnetic field, these spin-dependent reactions essentially realize a biochemical magnetometer. Using the quantum Fisher information, we find the fundamental quantum limits to the magnetic sensitivity of radical-pair magnetometers, arriving at a sensitivity δ B =2 pT /τ [1 μ s] √{ν0[1012] } , given in terms of radical-pair lifetime τ and number of radical pairs ν0. We then explore how well the usual measurement scheme considered in radical-pair reactions, the measurement of reaction yields, approaches the fundamental limits. In doing so, we find the optimal hyperfine interaction Hamiltonian that leads to the best magnetic sensitivity as obtained from reaction yields. This is still an order of magnitude smaller than the absolute quantum limit. Finally, we demonstrate that with a realistic quantum reaction control reminding one of Ramsey interferometry, here presented as a quantum circuit involving the spin-exchange interaction and a recently proposed molecular switch, we can approach the fundamental quantum limit within a factor of 2. This work opens the application of well-advanced quantum metrology methods to biological systems.

  5. Exploring the Use of Alfven Waves in Magnetometer Calibration at Geosynchronous Orbit

    Science.gov (United States)

    Bentley, John; Sheppard, David; RIch, Frederick; Redmon, Robert; Loto'aniu, Paul; Chu, Donald

    2016-01-01

    An Alfven wave is a type magnetohydrodynamicwave that travels through a conducting fluid under the influence of a magnetic field. Researchers have successfully calculated offset vectors of magnetometers in interplanetary space by optimizing the offset to maximize certain Alfvenic properties of observed waves (Leinweber, Belcher). If suitable Alfven waves can be found in the magnetosphere at geosynchronous altitude then these techniques could be used to augment the overall calibration plan for magnetometers in this region such as on the GOES spacecraft, possibly increasing the time between regular maneuvers. Calibration maneuvers may be undesirable because they disrupt the activities of other instruments. Various algorithms to calculate an offset using Alfven waves were considered. A new variation of the Davis-Smith method was derived because it can be mathematically shown that the Davis-Smith method tolerates filtered data, which expands potential applications. The variant developed was designed to find only the offset in the plane normal to the main field because the overall direction of Earth's magnetic field rarely changes, and theory suggests the Alfvenic disturbances occur transverse to the main field. Other variations of the Davis-Smith method encounter problems with data containing waves that propagate in mostly the same direction. A searching algorithm was then designed to look for periods of time with potential Alfven waves in GOES 15 data based on parameters requiring that disturbances be normal to the main field and not change field magnitude. Final waves for calculation were hand-selected. These waves produced credible two-dimensional offset vectors when input to the Davis-Smith method. Multiple two-dimensional solutions in different planes can be combined to get a measurement of the complete offset. The resulting three dimensional offset did not show sufficient precision over several years to be used as a primary calibration method, but reflected

  6. The Mesospheric Sodium Layer as a Remotely, Optically Pumped Magnetometer for Investigation of Birkeland Currents

    Science.gov (United States)

    Matzka, J.; Johnsen, M. G.; Hoppe, U. P.; Serrano, A.

    2016-12-01

    By means of optical pumping, it is possible to use the naturally occurring sodium layer in the mesosphere to measure Earth's scalar magnetic field at 90 km above ground. This is an altitude not accessible by other means than rockets, which only will provide point measurements of very short time scales. We are planning to modify the sodium lidar at ALOMAR in Northern Norway to be able, for the first time, to measure and monitor the magnetic field in situ in the high latitude mesosphere over longer time scales. The planned modifications to the lidar instrument will allow alternating between the new magnetometer mode and its present mode for atmospheric temperatures and winds. The technique, which has been proposed earlier for measurements at low or mid-latitudes for studies of Earth's internal magnetic field, will in our project be applied to high latitudes in the auroral zone. This opens for a completely new domain of measurements of externally generated geomagnetic variations related to currents in the magnetosphere-ionosphere system. In particular, we aim to measure the magnetic field variations in close vicinity to Birkeland currents associated with particle precipitation events penetrating to altitudes below 90 km and small-scale, discrete auroral arcs. It is, furthermore, anticipated that it will be possible to detect horizontal current structures in the E-layer on much smaller length scales than it is presently possible from ground observations alone. During the project we plan take advantage of the rich space science infrastructure located in northern Norway, including ALOMAR, EISCAT and the Tromsø Geophysical Observatory magnetometer network. If possible, we also aim to make measurements in conjunction with overpasses of the SWARM satellites.

  7. Fullerene Transport in Saturated Porous Media

    Science.gov (United States)

    We investigated the effects of background solution chemistry and residence time within the soil column on the transport of aqu/C60 through saturated ultrapure quartz sand columns. Aqu/C60 breakthrough curves were obtained under different pore water velocities, solution pHs, and i...

  8. Oxygenation of saturated and unsaturated hydrocarbons with ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 118; Issue 5. Oxygenation of saturated and unsaturated hydrocarbons with sodium periodate catalyzed by manganese(III) tetra-arylporphyrins, to study the axial ligation of imidazole. Reza Tayebee. Volume 118 Issue 5 September 2006 pp 429-433 ...

  9. Nasal pulse oximetry overestimates oxygen saturation

    DEFF Research Database (Denmark)

    Rosenberg, J; Pedersen, M H

    1990-01-01

    Ten surgical patients were monitored with nasal and finger pulse oximetry (Nellcor N-200) for five study periods with alternating mouth and nasal breathing and switching of cables and sensors. Nasal pulse oximetry was found to overestimate arterial oxygen saturation by 4.7 (SD 1.4%) (bias...

  10. Determination of saturated and unsaturated hydraulic conductivity ...

    African Journals Online (AJOL)

    The estimation of hydraulic conductivity indicates how fluids flow through a substance and thus determine the water balance in the soil profile. In determining the saturated and unsaturated hydraulic conductivity of soil, five plots of 5.0 x 4.0 m were prepared with a PVC access tube installed in each plot. The plots were ...

  11. Understanding 'saturation' of radar signals over forests.

    Science.gov (United States)

    Joshi, Neha; Mitchard, Edward T A; Brolly, Matthew; Schumacher, Johannes; Fernández-Landa, Alfredo; Johannsen, Vivian Kvist; Marchamalo, Miguel; Fensholt, Rasmus

    2017-06-14

    There is an urgent need to quantify anthropogenic influence on forest carbon stocks. Using satellite-based radar imagery for such purposes has been challenged by the apparent loss of signal sensitivity to changes in forest aboveground volume (AGV) above a certain 'saturation' point. The causes of saturation are debated and often inadequately addressed, posing a major limitation to mapping AGV with the latest radar satellites. Using ground- and lidar-measurements across La Rioja province (Spain) and Denmark, we investigate how various properties of forest structure (average stem height, size and number density; proportion of canopy and understory cover) simultaneously influence radar backscatter. It is found that increases in backscatter due to changes in some properties (e.g. increasing stem sizes) are often compensated by equal magnitude decreases caused by other properties (e.g. decreasing stem numbers and increasing heights), contributing to the apparent saturation of the AGV-backscatter trend. Thus, knowledge of the impact of management practices and disturbances on forest structure may allow the use of radar imagery for forest biomass estimates beyond commonly reported saturation points.

  12. Wave propagation in thermoelastic saturated porous medium

    Indian Academy of Sciences (India)

    Biot 's theory for wave propagation in saturated porous solid is modified to study the propagation of thermoelastic waves in poroelastic medium. Propagation of plane harmonic waves is considered in isotropic poroelastic medium. Relations are derived among the wave-induced temperature in the medium and the ...

  13. Spontaneous emission from saturated parametric amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Ott, Johan Raunkjær; Steffensen, Henrik

    2009-01-01

    Noise performance of parametric amplifiers is typically calculated assuming un-depleted operation. However, in many applications especially when applied as regenerative amplifiers in systems based on phase shift keyed modulation schemes, this assumption is not valid. Here we show the impact...... on accumulated spontaneous emission for a parametric amplifier operated in saturation....

  14. Elevated transferrin saturation and risk of diabetes

    DEFF Research Database (Denmark)

    Ellervik, Christina; Mandrup-Poulsen, Thomas; Andersen, Henrik Ullits

    2011-01-01

    OBJECTIVE We tested the hypothesis that elevated transferrin saturation is associated with an increased risk of any form of diabetes, as well as type 1 or type 2 diabetes separately. RESEARCH DESIGN AND METHODS We used two general population studies, The Copenhagen City Heart Study (CCHS, N = 9...

  15. Saturated fat, carbohydrates and cardiovascular disease

    NARCIS (Netherlands)

    Kuipers, R. S.; de Graaf, D. J.; Luxwolda, M. F.; Muskiet, M. H. A.; Dijck-Brouwer, D. A. J.; Muskiet, F. A. J.

    The dietary intake of saturated fatty acids (SAFA) is associated with a modest increase in serum total cholesterol, but not with cardiovascular disease (CVD). Replacing dietary SAFA with carbohydrates (CHO), notably those with a high glycaemic index, is associated with an increase in CVD risk in

  16. Two-beam interaction in saturable media

    DEFF Research Database (Denmark)

    Schjødt-Eriksen, Jens; Schmidt, Michel R.; Juul Rasmussen, Jens

    1998-01-01

    The dynamics of two coupled soliton solutions of the nonlinear Schrodinger equation with a saturable nonlinearity is investigated It is shown by means of a variational method and by direct numerical calculations that two well-separated solitons can orbit around each other, if their initial velocity...

  17. Synthesis and characterization of saturated polyester and ...

    Indian Academy of Sciences (India)

    Saturated polyester resin, derived from the glycolysis of polyethyleneterephthalate (PET) was examined as an effective way for PET recycling. The glycolyzed PET (GPET) was reacted with the mixture of phthalic anhydride and ethylene glycol (EG) with varied compositions and their reaction kinetic were studied. During ...

  18. Multi-spectral imaging of oxygen saturation

    Science.gov (United States)

    Savelieva, Tatiana A.; Stratonnikov, Aleksander A.; Loschenov, Victor B.

    2008-06-01

    The system of multi-spectral imaging of oxygen saturation is an instrument that can record both spectral and spatial information about a sample. In this project, the spectral imaging technique is used for monitoring of oxygen saturation of hemoglobin in human tissues. This system can be used for monitoring spatial distribution of oxygen saturation in photodynamic therapy, surgery or sports medicine. Diffuse reflectance spectroscopy in the visible range is an effective and extensively used technique for the non-invasive study and characterization of various biological tissues. In this article, a short review of modeling techniques being currently in use for diffuse reflection from semi-infinite turbid media is presented. A simple and practical model for use with a real-time imaging system is proposed. This model is based on linear approximation of the dependence of the diffuse reflectance coefficient on relation between absorbance and reduced scattering coefficient. This dependence was obtained with the Monte Carlo simulation of photon propagation in turbid media. Spectra of the oxygenated and deoxygenated forms of hemoglobin differ mostly in the red area (520 - 600 nm) and have several characteristic points there. Thus four band-pass filters were used for multi-spectral imaging. After having measured the reflectance, the data obtained are used for fitting the concentration of oxygenated and free hemoglobin, and hemoglobin oxygen saturation.

  19. Microscopic analysis of saturable absorbers: Semiconductor saturable absorber mirrors versus graphene

    Energy Technology Data Exchange (ETDEWEB)

    Hader, J.; Moloney, J. V. [Nonlinear Control Strategies, Inc., 3542 N. Geronimo Ave., Tucson, Arizona 85705 (United States); College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); Yang, H.-J.; Scheller, M. [College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); Koch, S. W. [Department of Physics and Materials Sciences Center, Philipps Universität Marburg, Renthof 5, 35032 Marburg (Germany)

    2016-02-07

    Fully microscopic many-body calculations are used to study the influence of strong sub-picosecond pulses on the carrier distributions and corresponding optical response in saturable absorbers used for mode-locking—semiconductor (quantum well) saturable absorber mirrors (SESAMs) and single layer graphene based saturable absorber mirrors (GSAMs). Unlike in GSAMs, the saturation fluence and recovery time in SESAMs show a strong spectral dependence. While the saturation fluence in the SESAM is minimal at the excitonic bandgap, the optimal recovery time and least pulse distortion due to group delay dispersion are found for excitation higher in the first subband. For excitation near the SESAM bandgap, the saturation fluence is about one tenth of that in the GSAM. At energies above the bandgap, the fluences in both systems become similar. A strong dependence of the saturation fluence on the pulse width in both systems is caused by carrier relaxation during the pulse. The recovery time in graphene is found to be about two to four times faster than that in the SESAMs. The occurrence of negative differential transmission in graphene is shown to be caused by dopant related carriers. In SESAMs, a negative differential transmission is found when exciting below the excitonic resonance where excitation induced dephasing leads to an enhancement of the absorption. Comparisons of the simulation data to the experiment show a very good quantitative agreement.

  20. Microscopic analysis of saturable absorbers: Semiconductor saturable absorber mirrors versus graphene

    Science.gov (United States)

    Hader, J.; Yang, H.-J.; Scheller, M.; Moloney, J. V.; Koch, S. W.

    2016-02-01

    Fully microscopic many-body calculations are used to study the influence of strong sub-picosecond pulses on the carrier distributions and corresponding optical response in saturable absorbers used for mode-locking—semiconductor (quantum well) saturable absorber mirrors (SESAMs) and single layer graphene based saturable absorber mirrors (GSAMs). Unlike in GSAMs, the saturation fluence and recovery time in SESAMs show a strong spectral dependence. While the saturation fluence in the SESAM is minimal at the excitonic bandgap, the optimal recovery time and least pulse distortion due to group delay dispersion are found for excitation higher in the first subband. For excitation near the SESAM bandgap, the saturation fluence is about one tenth of that in the GSAM. At energies above the bandgap, the fluences in both systems become similar. A strong dependence of the saturation fluence on the pulse width in both systems is caused by carrier relaxation during the pulse. The recovery time in graphene is found to be about two to four times faster than that in the SESAMs. The occurrence of negative differential transmission in graphene is shown to be caused by dopant related carriers. In SESAMs, a negative differential transmission is found when exciting below the excitonic resonance where excitation induced dephasing leads to an enhancement of the absorption. Comparisons of the simulation data to the experiment show a very good quantitative agreement.

  1. Prospecting For Magnetite Ore Deposits With A Innovative Sensor's of Unique Fundamentally New Magnetometer.

    Science.gov (United States)

    Emelianenko, T. I.; Tachaytdinov, R. S.; Sarichev, V. F.; Kotov, B. V.; Susoeva, G. N.

    After careful study of principles and abilities of all existing magnetmeters of all three revolutions in magnetic prospecting we have come to the conclusion that they cannot solve local guestions of the magnetic prospecting or determine centre coordinates of magnetite ore body before drilling Electromagnetism lows and achievents magnetprospectings and radioelectronics of all 20th century serve as a theoretical base of the "locator". While creating this cardinally new magnetmeter , we borrowed different things from radio-prospectors, magnetprospectors, wireless operators and combined all of them while creating the "locators''. The "locators' construction is bas ed on the "magnetic intensification" principle ,owing to which this "locators" are characterised by hight sensitiveness and ability to determine centers of even little commercial magnetite ore deposits with relatively weak magnetic anomalies. The main advantage of the "locators" over existing ones is that it can solve local questions determine centre coordinates. A remarkably simple locator construction determine direction of the on-surface measurings towards the ore body centre and gives approximate prognosis resourses before/withour/ drilling. The "locators" were worked out for the first time in history , they have 2 licences. The fundamental design and drawbacks of the existing magnetometers have been inherited from the original magnetometre dating back two or three hundred years. The developers of the existing magnetometres have all gone along the same well- beaten track of replacing the primitive sensor in the form of a piece of ore hung on a string at first by an arrow sensor and later by magnetically oriented protons and quanta, with amplification of the sensors' OUTPUT signal. Furthermore, all the existing magnetometres are imperfect in that they, lacking the directivity of the ground-level magnetic measurements, only record the overall magnetic vector field generated by all the ore bodies around the

  2. Replacing foods high in saturated fat by low-saturated fat alternatives: a computer simulation of the potential effects on reduction of saturated fat consumption

    NARCIS (Netherlands)

    Schickenberg, B.; Assema, P.; Brug, J.; Verkaik-Kloosterman, J.; Ocke, M.C.; Vries, de N.

    2009-01-01

    10 en%) increased from 23.3 % to 86.0 %. We conclude that the replacement of relatively few important high-saturated fat products by available lower-saturated fat alternatives can significantly reduce saturated fat intake and increase the proportion of individuals complying with recommended intake

  3. Industrial survey of core handling, storage, and analysis procedures for ROS measurements. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ward, C.E.; Barnwell, J.L.

    1980-10-01

    Core analysis is an essential function in the evaluation of residual oil saturation of a reservoir. This report describes the basic techniques of core handling and measurement of porosity, permeability, and fluid saturations. Special analysis techniques such as wettability, imbibition, capillary pressure and waterflood tests are also described. Interviews with industry experts provided opinions on the applicability and reliability of the various alternative testing procedures as well as an estimation of the size of the US domestic market in coring and core analysis services.

  4. Investigating Size- and Temperature-Dependent Coercivity and Saturation Magnetization in PEG Coated Fe3O4 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Chiranjib Nayek

    2017-05-01

    Full Text Available Polyethylene glycol (PEG coated magnetic Fe3O4 nanoparticles with diameters of 12 nm, 15 nm, and 16 nm were synthesized by the usual co-precipitation method. The structure and morphology of the samples were characterized using X-ray diffraction (XRD and high resolution transmission electron microscopy (HRTEM. The ac magnetic susceptibility measurements were carried out using a vibrating sample magnetometer (VSM. The dc magnetic measurements were carried out using a commercial Quantum Design superconducting quantum interference device (SQUID. The XRD patterns indicated the sole existence of the inverse cubic spinel phase of Fe3O4 in all the samples. The histograms extracted from the TEM images show narrow size distributions with average sizes that are very similar to those obtained from the XRD images using the Scherrer’s formula. The temperature dependence of both coercivity and saturation magnetization, which were determined from the magnetic hysteresis loops, were found to have considerable deviations from the Bloch’s and Kneller’s laws. The size-dependent coercivity and saturation magnetization were found to be non-monotonic at nearly all temperatures. These results are discussed and attributed mainly to the finite size effects in addition to the existence of inter-particle interactions and of spin-glass structures that resulted from frozen canted surface spins at low temperatures.

  5. Comparison of pulseoximetry oxygen saturation and arterial oxygen saturation in open heart intensive care unit

    Directory of Open Access Journals (Sweden)

    Alireza Mahoori

    2013-08-01

    Full Text Available Background: Pulseoximetry is widely used in the critical care setting, currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SPO2 (puls-eoximetry oxygen saturation in intensive care unit after cardiac surgery. Our objective was to compare pulseoximetry with arterial oxygen saturation (SaO2 during clinical routine in such patients, and to examine the effect of mild acidosis on this relationship.Methods: In an observational prospective study 80 patients were evaluated in intensive care unit after cardiac surgery. SPO2 was recorded and compared with SaO2 obtained by blood gas analysis. One or serial arterial blood gas analyses (ABGs were performed via a radial artery line while a reliable pulseoximeter signal was present. One hundred thirty seven samples were collected and for each blood gas analyses, SaO2 and SPO2 we recorded.Results: O2 saturation as a marker of peripheral perfusion was measured by Pulseoxim-etry (SPO2. The mean difference between arterial oxygen saturation and pulseoximetry oxygen saturation was 0.12%±1.6%. A total of 137 paired readings demonstrated good correlation (r=0.754; P<0.0001 between changes in SPO2 and those in SaO2 in samples with normal hemoglobin. Also in forty seven samples with mild acidosis, paired readings demonstrated good correlation (r=0.799; P<0.0001 and the mean difference between SaO2 and SPO2 was 0.05%±1.5%.Conclusion: Data showed that in patients with stable hemodynamic and good signal quality, changes in pulseoximetry oxygen saturation reliably predict equivalent changes in arterial oxygen saturation. Mild acidosis doesn’t alter the relation between SPO2 and SaO2 to any clinically important extent. In conclusion, the pulse oximeter is useful to monitor oxygen saturation in patients with stable hemodynamic.

  6. [Monitoring of jugular venous oxygen saturation].

    Science.gov (United States)

    Nakamura, Shunsuke

    2011-04-01

    The continuous monitoring of jugular venous oxygen saturation(SjO2) has become a practical method for monitoring global cerebral oxygenation and metabolism. SjO2 reflects the balance between the cerebral blood flow and the cerebral metabolic rate for oxygen (CMRO2), if arterial oxyhemoglobin saturation, hemoglobin concentration remain constant. Normal SjO2 values range between 55% and 75%. Low SjO2 indicates cerebral hypoperfusion or ischemia. Conversely, an increased SjO2 indicates either cerebral hyperemia or a disorder that decreases CMRO2. In minimizing secondary brain damage following resuscitation from cardiopulmonary arrest, SjO2 monitoring is thus considered to be an integral part of multimodality monitoring and can provide important information for the management of patients in neurointensive care.

  7. The danish tax on saturated fat

    DEFF Research Database (Denmark)

    Jensen, Jørgen Dejgård; Smed, Sinne

    Denmark introduced a new tax on saturated fat in food products with effect from October 2011. The objective of this paper is to make an effect assessment of this tax for some of the product categories most significantly affected by the new tax, namely fats such as butter, butter-blends, margarine...... on saturated fat in food products has had some effects on the market for the considered products, in that the level of consumption of fats dropped by 10 – 20%. Furthermore, the analysis points at shifts in demand from high-price supermarkets towards low-price discount stores – a shift that seems to have been...... – and broaden – the analysis at a later stage, when data are available for a longer period after the introduction of the fat tax....

  8. Nonlinear saturation of Weibel-type instabilities

    Science.gov (United States)

    Srinivasan, Bhuvana; Cagas, Petr; Hakim, Ammar

    2017-10-01

    Weibel-type instabilities, which grow in plasmas with anisotropic velocity distribution, have been studied for many years and drawn recent interest due to their broad applicability spanning from laboratory laser plasmas to origins of intergalactic magnetic fields in astrophysical plasmas. Magnetic particle trapping has been considered as the main mechanism of the nonlinear saturation of these instabilities. However, novel continuum kinetic and two-fluid five moment simulations show that there are additional effects - the transverse flow introduced by the magnetic field creates a secondary electrostatic two-stream instability which alters the saturation and is responsible for a quasi-periodic behavior in the nonlinear phase. This research was supported by the Air Force Office of Scientific Research under Grant Number FA9550-15-1-0193.

  9. WAter Saturation Shift Referencing (WASSR) for chemical exchange saturation transfer experiments

    Science.gov (United States)

    Kim, Mina; Gillen, Joseph; Landman, Bennett. A.; Zhou, Jinyuan; van Zijl, Peter C.M.

    2010-01-01

    Chemical exchange saturation transfer (CEST) is a contrast mechanism exploiting exchange-based magnetization transfer (MT) between solute and water protons. CEST effects compete with direct water saturation and conventional MT processes and generally can only be quantified through an asymmetry analysis of the water saturation spectrum (Z-spectrum) with respect to the water frequency, a process that is exquisitely sensitive to magnetic field inhomogeneities. Here, it is shown that direct water saturation imaging allows measurement of the absolute water frequency in each voxel, allowing proper centering of Z-spectra on a voxel-by-voxel basis independent of spatial B0 field variations. Optimal acquisition parameters for this “water saturation shift referencing” or “WASSR” approach were estimated using Monte Carlo simulations and later confirmed experimentally. The optimal ratio of the WASSR sweep width to the linewidth of the direct saturation curve was found to be 3.3–4.0, requiring a sampling of 16–32 points. The frequency error was smaller than 1 Hz at signal to noise ratios of 40 or higher. The WASSR method was applied to study glycogen, where the chemical shift difference between the hydroxyl (OH) protons and bulk water protons at 3T is so small (0.75–1.25 ppm) that the CEST spectrum is inconclusive without proper referencing. PMID:19358232

  10. Water saturation shift referencing (WASSR) for chemical exchange saturation transfer (CEST) experiments.

    Science.gov (United States)

    Kim, Mina; Gillen, Joseph; Landman, Bennett A; Zhou, Jinyuan; van Zijl, Peter C M

    2009-06-01

    Chemical exchange saturation transfer (CEST) is a contrast mechanism that exploits exchange-based magnetization transfer (MT) between solute and water protons. CEST effects compete with direct water saturation and conventional MT processes, and generally can only be quantified through an asymmetry analysis of the water saturation spectrum (Z-spectrum) with respect to the water frequency, a process that is exquisitely sensitive to magnetic field inhomogeneities. Here it is shown that direct water saturation imaging allows measurement of the absolute water frequency in each voxel, allowing proper centering of Z-spectra on a voxel-by-voxel basis independently of spatial B(0) field variations. Optimal acquisition parameters for this "water saturation shift referencing" (WASSR) approach were estimated using Monte Carlo simulations and later confirmed experimentally. The optimal ratio of the WASSR sweep width to the linewidth of the direct saturation curve was found to be 3.3-4.0, requiring a sampling of 16-32 points. The frequency error was smaller than 1 Hz at signal-to-noise ratios of 40 or higher. The WASSR method was applied to study glycogen, where the chemical shift difference between the hydroxyl (OH) protons and bulk water protons at 3T is so small (0.75-1.25 ppm) that the CEST spectrum is inconclusive without proper referencing.

  11. Gluon saturation beyond (naive) leading logs

    Energy Technology Data Exchange (ETDEWEB)

    Beuf, Guillaume

    2014-12-15

    An improved version of the Balitsky–Kovchegov equation is presented, with a consistent treatment of kinematics. That improvement allows to resum the most severe of the large higher order corrections which plague the conventional versions of high-energy evolution equations, with approximate kinematics. This result represents a further step towards having high-energy QCD scattering processes under control beyond strict Leading Logarithmic accuracy and with gluon saturation effects.

  12. 2D Saturable Absorbers for Fibre Lasers

    Directory of Open Access Journals (Sweden)

    Robert I. Woodward

    2015-11-01

    Full Text Available Two-dimensional (2D nanomaterials are an emergent and promising platform for future photonic and optoelectronic applications. Here, we review recent progress demonstrating the application of 2D nanomaterials as versatile, wideband saturable absorbers for Q-switching and mode-locking fibre lasers. We focus specifically on the family of few-layer transition metal dichalcogenides, including MoS2, MoSe2 and WS2.

  13. Stabilization of Neutral Systems with Saturating Actuators

    Directory of Open Access Journals (Sweden)

    F. El Haoussi

    2012-01-01

    to determine stabilizing state-feedback controllers with large domain of attraction, expressed as linear matrix inequalities, readily implementable using available numerical tools and with tuning parameters that make possible to select the most adequate solution. These conditions are derived by using a Lyapunov-Krasovskii functional on the vertices of the polytopic description of the actuator saturations. Numerical examples demonstrate the effectiveness of the proposed technique.

  14. Low-Frequency Noise in High-T Superconductor Josephson Junctions, Squids, and Magnetometers.

    Science.gov (United States)

    Miklich, Andrew Hostetler

    The design and performance of high-T_ {rm c} dc superconducting quantum interference devices (SQUIDs), the junctions that comprise them, and magnetometers made from them are described, with special attention paid to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUIDs. This noise suggests a poorly connected interface at the grain boundary junction. SQUIDs from bicrystal junctions, in contrast, have levels of critical current noise that are controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5times 10^{-30} J Hz^ {-1} at 1 Hz is reported. Magnetometers in which a (9 mm)^2 pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz^{-1/2} down to frequencies below 1 Hz, improving to 39 fT Hz^{-1/2} at 1 Hz with the addition of a 50 mm-diameter single-turn flux transformer. Although the performance of these devices is sufficient for single -channel biomagnetometry or geophysical studies, their relatively poor coupling to the pickup loop makes it difficult to satisfy the competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz^{-1/2} in the white noise region is reported with a (10 mm) ^2 pickup loop. However, additional 1/f noise from the processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz^ {-1/2}. High-T_{ rm c} SQUIDs are shown to exhibit additional 1/f noise when they are cooled in a nonzero static magnetic field because of the additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10-20 in a field of 0.05 mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution

  15. Low-frequency noise in high-(Tc) superconductor Josephson junctions, SQUIDs, and magnetometers

    Science.gov (United States)

    Miklich, A. H.

    1994-05-01

    Design and performance of high-T(sub c) dc superconducting quantum interference devices (SQUID's), junctions that comprise them, and magnetometers made from them are described, with attention to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUID's; this suggests a poorly connected interface at the grain boundary junction. SQUID's from bicrystal junctions have levels of critical current noise controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5 x 10(exp -30) J Hz(exp -1) at 1 Hz is reported. Magnetometers in which a (9 mm)(exp 2) pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz(exp -1/2) down to frequencies below 1 Hz, improving to 39 fT Hz(exp -1/2) at 1 Hz with the addition of a 50mm-diameter single-turn flux transformer. Poor coupling to pickup loop makes it difficult to satisfy competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz(exp -1/2) in the white noise region is reported with a (10 mm)(exp 2) pickup loop. However, additional 1/f noise from processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz(exp -1/2). High-T(sub c) SQUID's exhibit additional 1/f noise when cooled in a nonzero static magnetic field because of additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10-20 in a field of 0.05mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution of 9.2 pV Hz(exp -1/2) at 10 Hz (24 pV Hz(exp -1/2) at 1 Hz) is described.

  16. Electrodynamics of an omega-band as deduced from optical and magnetometer data

    Directory of Open Access Journals (Sweden)

    H. Vanhamäki

    2009-09-01

    Full Text Available We investigate an omega-band event that took place above northern Scandinavia around 02:00–02:30 UT on 9 March 1999. In our analysis we use ground based magnetometer, optical and riometer measurements together with satellite based optical images. The optical and riometer data are used to estimate the ionospheric Hall and Pedersen conductances, while ionospheric equivalent currents are obtained from the magnetometer measurements. These data sets are used as input in a local KRM calculation, which gives the ionospheric potential electric field as output, thus giving us a complete picture of the ionospheric electrodynamic state during the omega-band event. The overall structure of the electric field and field-aligned current (FAC provided by the local KRM method are in good agreement with previous studies. Also the E×B drift velocity calculated from the local KRM solution is in good qualitative agreement with the plasma velocity measured by the Finnish CUTLASS radar, giving further support for the new local KRM method. The high-resolution conductance estimates allow us to discern the detailed structure of the omega-band current system. The highest Hall and Pedersen conductances, ~50 and ~25 S, respectively, are found at the edges of the bright auroral tongue. Inside the tongue, conductances are somewhat smaller, but still significantly higher than typical background values. The electric field shows a converging pattern around the tongues, and the field strength drops from ~40 mV/m found at optically dark regions to ~10 mV/m inside the areas of enhanced conductivity. Downward FAC flow in the dark regions, while upward currents flow inside the auroral tongue. Additionally, sharp conductance gradients at the edge of an auroral tongue are associated with narrow strips of intense FACs, so that a strip of downward current flows at the eastern (leading edge and a similar strip of upward current is present at the western (trailing edge. The Joule

  17. Saturated Dispersive Extinction Theory of Red Shift

    Science.gov (United States)

    Wang, Ling Jun

    2012-03-01

    The Dispersive Extinction Theory (DET) proposed by WangfootnotetextWang, Ling Jun, Physics Essays, 18, No. 2, (2005). offers an alternative to the Big Bang. According to DET, the cosmic red shift is caused by the dispersive extinction of the star light during the propagation from the stars to the earth, instead of being caused by the Doppler shift due to the expansion of the universe.footnotetextHubble, E., Astrophys. J. 64, 321 (1926).^,footnotetextHubble, E., The Realm of the Nebulae, (Yale University Press, New Haven, 1936). DET allows an infinite, stable, non expanding universe, and is immune of the fundamental problems inherent to the Big Bang such as the horizon problem, the extreme violation of the conservation of mass, energy and charge, and the geocentric nature which violates the principle of relativity.footnotetextWang, Ling Jun, Physics Essays, 20, No. 2, (2007). The scenario dealt with in Reference (1) is a one in which the extinction by the space medium is not saturated. This work deals with a different scenario when the extinction is saturated. The saturated extinction causes limited energy loss, and the star light can travel a much greater distance than in the unsaturated scenario.

  18. Optimal oxygen saturation in premature infants

    Directory of Open Access Journals (Sweden)

    Meayoung Chang

    2011-09-01

    Full Text Available There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebral palsy. It is still unclear what range of oxygen saturation is appropriate for premature infants; however, until the results of further studies are available, a reasonable target for pulse oxygen saturation (SpO2 is 90 to 93% with an intermittent review of the correlation between SpO2 and the partial pressure of arterial oxygen tension (PaO2. Because optimal oxygenation depends on individuals at the bedside making ongoing adjustments, each unit must define an optimal target range and set alarm limits according to their own equipment or conditions. All staff must be aware of these values and adjust the concentration of supplemental oxygen frequently.

  19. Animal MRI Core

    Data.gov (United States)

    Federal Laboratory Consortium — The Animal Magnetic Resonance Imaging (MRI) Core develops and optimizes MRI methods for cardiovascular imaging of mice and rats. The Core provides imaging expertise,...

  20. Fluxgate vector magnetometers: Compensated multi-sensor devices for ground, UAV and airborne magnetic survey for various application in near surface geophysics

    Science.gov (United States)

    Gavazzi, Bruno; Le Maire, Pauline; Munschy, Marc; Dechamp, Aline

    2017-04-01

    Fluxgate 3-components magnetometer is the kind of magnetometer which offers the lightest weight and lowest power consumption for the measurement of the intensity of the magnetic field. Moreover, vector measurements make it the only kind of magnetometer allowing compensation of magnetic perturbations due to the equipment carried with it. Unfortunately, Fluxgate magnetometers are quite uncommon in near surface geophysics due to the difficulty to calibrate them precisely. The recent advances in calibration of the sensors and magnetic compensation of the devices from a simple process on the field led Institut de Physique du Globe de Strasbourg to develop instruments for georeferenced magnetic measurements at different scales - from submetric measurements on the ground to aircraft-conducted acquisition through the wide range offered by unmanned aerial vehicles (UAVs) - with a precision in the order of 1 nT. Such equipment is used for different kind of application: structural geology, pipes and UXO detection, archaeology.

  1. Preparation of core-shell magnetic molecular imprinted polymer with binary monomer for the fast and selective extraction of bisphenol A from milk.

    Science.gov (United States)

    Yuan, Yanhao; Liu, Yan; Teng, Weidi; Tan, Jiean; Liang, Yong; Tang, Youwen

    2016-09-02

    In the current study, a new strategy for the extraction of bisphenol A (BPA) from milk has been employed by using surface-imprinted core-shell magnetic beads, prepared by the reversible addition-fragmentation chain transfer (RAFT) polymerization. In order to obtain highly selective recognition cavities, an enhanced imprinting method based on binary functional monomers, e.g. 4-vinylpyridine (4-VP) and β-cyclodextrin (β-CD), was chosen for BPA imprinting. The morphological and magnetic properties of the Fe3O4-MIP beads were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FT-IR) Spectroscopy, Thermogravimetric Analysis (TGA), and Vibrating Sample Magnetometer (VSM). The characterization results suggested that MIP was synthesized evenly on Fe3O4-SiO2 surface. The adsorption experiments revealed that Fe3O4-MIPs showed better extraction capacity and selectivity toward BPA and its analogues than the non-imprinted polymers (NIPs). The saturation capacity of Fe3O4-MIP was 17.98mg/g. In milk samples, the present method displayed a lower the detection thresholds, down to 3.7μg/L. The recoveries of BPA in milk samples for three concentrations were found to be within 99.21%, 98.07% and 97.23%, respectively to three concentrations: 1.0μmol/L, 10.0mol/L, 100.0μmol/L. Thus, the MIPs can be used for remove BPA in milk samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Unsaturated Zone and Saturated Zone Transport Properties (U0100)

    Energy Technology Data Exchange (ETDEWEB)

    J. Conca

    2000-12-20

    This Analysis/Model Report (AMR) summarizes transport properties for the lower unsaturated zone hydrogeologic units and the saturated zone at Yucca Mountain and provides a summary of data from the Busted Butte Unsaturated Zone Transport Test (UZTT). The purpose of this report is to summarize the sorption and transport knowledge relevant to flow and transport in the units below Yucca Mountain and to provide backup documentation for the sorption parameters decided upon for each rock type. Because of the complexity of processes such as sorption, and because of the lack of direct data for many conditions that may be relevant for Yucca Mountain, data from systems outside of Yucca Mountain are also included. The data reported in this AMR will be used in Total System Performance Assessment (TSPA) calculations and as general scientific support for various Process Model Reports (PMRs) requiring knowledge of the transport properties of different materials. This report provides, but is not limited to, sorption coefficients and other relevant thermodynamic and transport properties for the radioisotopes of concern, especially neptunium (Np), plutonium (Pu), Uranium (U), technetium (Tc), iodine (I), and selenium (Se). The unsaturated-zone (UZ) transport properties in the vitric Calico Hills (CHv) are discussed, as are colloidal transport data based on the Busted Butte UZTT, the saturated tuff, and alluvium. These values were determined through expert elicitation, direct measurements, and data analysis. The transport parameters include information on interactions of the fractures and matrix. In addition, core matrix permeability data from the Busted Butte UZTT are summarized by both percent alteration and dispersion.

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

    Energy Technology Data Exchange (ETDEWEB)

    Garaio, E., E-mail: eneko.garayo@ehu.es [Elektrizitatea eta Elektronika Saila, UPV/EHU, P.K. 644, Bilbao (Spain); Collantes, J.M. [Elektrizitatea eta Elektronika Saila, UPV/EHU, P.K. 644, Bilbao (Spain); Garcia, J.A. [Fisika Aplikatua II Saila, UPV/EHU, P.K. 644, Bilbao (Spain); Plazaola, F. [Elektrizitatea eta Elektronika Saila, UPV/EHU, P.K. 644, Bilbao (Spain); Mornet, S. [Institut de Chimie de la Matière Condensée de Bordeaux, UPR 9048 CNRS / Université de Bordeaux, Bordeaux (France); Couillaud, F. [Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS / Université de Bordeaux, Bordeaux (France); Sandre, O., E-mail: olivier.sandre@enscbp.fr [Laboratoire de Chimie des Polymères Organiques, UMR 5629 CNRS / Université de Bordeaux, Bordeaux (France)

    2014-11-15

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

  4. Determining the direction of a geometrical/optical reference axis in the coordinate system of a triaxial magnetometer sensor

    DEFF Research Database (Denmark)

    Primdahl, Fritz; Brauer, Peter; Merayo, José M.G.

    2002-01-01

    The reference coordinate axes of a magnetic vector field sensor are related to the instrument digital output vector (U) over bar by the calibration matrix C and the offset vector (O) over bar. In addition, this reference coordinate system must be related to (at least) two externally accessible op...... for two different positions, rotated about a fixed reference axis; (2) in the Earth's field the magnetometer sensor is rotated about a fixed axis into a number of (at least three) positions....

  5. Auto-Calibration Methods of Kinematic Parameters and Magnetometer Offset for the Localization of a Tracked Mobile Robot

    Directory of Open Access Journals (Sweden)

    Luciano Cantelli

    2016-11-01

    Full Text Available This paper describes an automatic calibration procedure adopted to improve the localization of an outdoor mobile robot. The proposed algorithm estimates, by using an extended Kalman filter, the main kinematic parameters of the vehicles, such as the wheel radii and the wheelbase as well as the magnetometer offset. Several trials have been performed to validate the proposed strategy on a tracked electrical mobile robot. The mobile robot is aimed to be adopted as a tool to help humanitarian demining operations.

  6. Elevated gas hydrate saturation within silt and silty clay sediments in the Shenhu area, South China Sea

    Science.gov (United States)

    Wang, Xiujuan; Hutchinson, Deborah R.; Wu, Shiguo; Yang, Shengxiong; Guo, Yiqun

    2011-01-01

    Gas hydrate saturations were estimated using five different methods in silt and silty clay foraminiferous sediments from drill hole SH2 in the South China Sea. Gas hydrate saturations derived from observed pore water chloride values in core samples range from 10 to 45% of the pore space at 190–221 m below seafloor (mbsf). Gas hydrate saturations estimated from resistivity (Rt) using wireline logging results are similar and range from 10 to 40.5% in the pore space. Gas hydrate saturations were also estimated by P wave velocity obtained during wireline logging by using a simplified three-phase equation (STPE) and effective medium theory (EMT) models. Gas hydrate saturations obtained from the STPE velocity model (41.0% maximum) are slightly higher than those calculated with the EMT velocity model (38.5% maximum). Methane analysis from a 69 cm long depressurized core from the hydrate-bearing sediment zone indicates that gas hydrate saturation is about 27.08% of the pore space at 197.5 mbsf. Results from the five methods show similar values and nearly identical trends in gas hydrate saturations above the base of the gas hydrate stability zone at depths of 190 to 221 mbsf. Gas hydrate occurs within units of clayey slit and silt containing abundant calcareous nannofossils and foraminifer, which increase the porosities of the fine-grained sediments and provide space for enhanced gas hydrate formation. In addition, gas chimneys, faults, and fractures identified from three-dimensional (3-D) and high-resolution two-dimensional (2-D) seismic data provide pathways for fluids migrating into the gas hydrate stability zone which transport methane for the formation of gas hydrate. Sedimentation and local canyon migration may contribute to higher gas hydrate saturations near the base of the stability zone.

  7. Non-invasive detection of animal nerve impulses with an atomic magnetometer operating near quantum limited sensitivity

    Science.gov (United States)

    Jensen, Kasper; Budvytyte, Rima; Thomas, Rodrigo A.; Wang, Tian; Fuchs, Annette M.; Balabas, Mikhail V.; Vasilakis, Georgios; Mosgaard, Lars D.; Stærkind, Hans C.; Müller, Jörg H.; Heimburg, Thomas; Olesen, Søren-Peter; Polzik, Eugene S.

    2016-07-01

    Magnetic fields generated by human and animal organs, such as the heart, brain and nervous system carry information useful for biological and medical purposes. These magnetic fields are most commonly detected using cryogenically-cooled superconducting magnetometers. Here we present the first detection of action potentials from an animal nerve using an optical atomic magnetometer. Using an optimal design we are able to achieve the sensitivity dominated by the quantum shot noise of light and quantum projection noise of atomic spins. Such sensitivity allows us to measure the nerve impulse with a miniature room-temperature sensor which is a critical advantage for biomedical applications. Positioning the sensor at a distance of a few millimeters from the nerve, corresponding to the distance between the skin and nerves in biological studies, we detect the magnetic field generated by an action potential of a frog sciatic nerve. From the magnetic field measurements we determine the activity of the nerve and the temporal shape of the nerve impulse. This work opens new ways towards implementing optical magnetometers as practical devices for medical diagnostics.

  8. High-sensitivity operation of single-beam optically pumped magnetometer in a kHz frequency range

    Science.gov (United States)

    Savukov, I.; Kim, Y. J.; Shah, V.; Boshier, M. G.

    2017-03-01

    Optically pumped magnetometers (OPM) can be used in various applications, from magnetoencephalography to magnetic resonance imaging and nuclear quadrupole resonance (NQR). OPMs provide high sensitivity and have the significant advantage of non-cryogenic operation. To date, many magnetometers have been demonstrated with sensitivity close to 1 fT, but most devices are not commercialized. Most recently, QuSpin developed a model of OPM that is low cost, high sensitivity, and convenient for users, which operates in a single-beam configuration. Here we developed a theory of single-beam (or parallel two-beam) magnetometers and showed that it is possible to achieve good sensitivity beyond their usual frequency range by tuning the magnetic field. Experimentally we have tested and optimized a QuSpin OPM for operation in the frequency range from DC to 1.7 kHz, and found that the performance was only slightly inferior despite the expected decrease due to deviation from the spin-exchange relaxation-free regime.

  9. Airborne gamma-ray spectrometer and magnetometer survey: Huron quadrangle, South Dakota. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over eleven (11) 2/sup 0/ x 1/sup 0/ NTMS quadrangles located in the states of Minnesota and Wisconsin and seven (7) 2/sup 0/ x 1/sup 0/ NTMS quadrangles in North and South Dakota. The quadrangles located within the North and South Dakota survey area include Devil's Lake, New Rockford, Jamestown, Aberdeen, Huron, Mitchell, and Sioux Falls. This report discusses the results obtained over the Huron map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately twenty-four (24) miles apart. A total of 21,481 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1459 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  10. Magnetic microscopic imaging with an optically pumped magnetometer and flux guides

    Science.gov (United States)

    Kim, Young Jin; Savukov, Igor; Huang, Jen-Huang; Nath, Pulak

    2017-01-01

    By combining an optically pumped magnetometer (OPM) with flux guides (FGs) and by installing a sample platform on automated translation stages, we have implemented an ultra-sensitive FG-OPM scanning magnetic imaging system that is capable of detecting magnetic fields of ˜20 pT with spatial resolution better than 300 μm (expected to reach ˜10 pT sensitivity and ˜100 μm spatial resolution with optimized FGs). As a demonstration of one possible application of the FG-OPM device, we conducted magnetic imaging of micron-size magnetic particles. Magnetic imaging of such particles, including nano-particles and clusters, is very important for many fields, especially for medical cancer diagnostics and biophysics applications. For rapid, precise magnetic imaging, we constructed an automatic scanning system, which holds and moves a target sample containing magnetic particles at a given stand-off distance from the FG tips. We show that the device was able to produce clear microscopic magnetic images of 10 μm-size magnetic particles. In addition, we also numerically investigated how the magnetic flux from a target sample at a given stand-off distance is transmitted to the OPM vapor cell.

  11. Airborne gamma-ray spectrometer and magnetometer survey, Medford Quadrangle Oregon. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Medford, Oregon, map area. Traverse lines were flown in an east-west direction at a line spacing of three miles. Tie lines were flown north-south approximately twelve miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 2925 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  12. The analysis of initial Juno magnetometer data using a sparse magnetic field representation

    Science.gov (United States)

    Moore, Kimberly M.; Bloxham, Jeremy; Connerney, John E. P.; Jørgensen, John L.; Merayo, José M. G.

    2017-05-01

    The Juno spacecraft, now in polar orbit about Jupiter, passes much closer to Jupiter's surface than any previous spacecraft, presenting a unique opportunity to study the largest and most accessible planetary dynamo in the solar system. Here we present an analysis of magnetometer observations from Juno's first perijove pass (PJ1; to within 1.06 RJ of Jupiter's center). We calculate the residuals between the vector magnetic field observations and that calculated using the VIP4 spherical harmonic model and fit these residuals using an elastic net regression. The resulting model demonstrates how effective Juno's near-surface observations are in improving the spatial resolution of the magnetic field within the immediate vicinity of the orbit track. We identify two features resulting from our analyses: the presence of strong, oppositely signed pairs of flux patches near the equator and weak, possibly reversed-polarity patches of magnetic field over the polar regions. Additional orbits will be required to assess how robust these intriguing features are.

  13. Signal Conditioning for the Kalman Filter: Application to Satellite Attitude Estimation with Magnetometer and Sun Sensors

    Directory of Open Access Journals (Sweden)

    Segundo Esteban

    2016-10-01

    Full Text Available Most satellites use an on-board attitude estimation system, based on available sensors. In the case of low-cost satellites, which are of increasing interest, it is usual to use magnetometers and Sun sensors. A Kalman filter is commonly recommended for the estimation, to simultaneously exploit the information from sensors and from a mathematical model of the satellite motion. It would be also convenient to adhere to a quaternion representation. This article focuses on some problems linked to this context. The state of the system should be represented in observable form. Singularities due to alignment of measured vectors cause estimation problems. Accommodation of the Kalman filter originates convergence difficulties. The article includes a new proposal that solves these problems, not needing changes in the Kalman filter algorithm. In addition, the article includes assessment of different errors, initialization values for the Kalman filter; and considers the influence of the magnetic dipole moment perturbation, showing how to handle it as part of the Kalman filter framework.

  14. Swarm Deployable Boom Assembly (DBA) Development of a Deployable Magnetometer Boom for the Swarm Spacecraft

    Science.gov (United States)

    McMahon, Paul; Jung, Hans-Juergen; Edwards, Jeff

    2013-09-01

    The Swarm programme consists of 3 magnetically clean satellites flying in close formation designed to measure the Earth's magnetic field using 2 Magnetometers mounted on a 4.3m long deployable boom.Deployment is initiated by releasing 3 HDRMs, once released the boom oscillates back and forth on a pair of pivots, similar to a restaurant kitchen door hinge, for around 120 seconds before coming to rest on 3 kinematic mounts which are used to provide an accurate reference location in the deployed position. Motion of the boom is damped through a combination of friction, spring hysteresis and flexing of the 120+ cables crossing the hinge. Considerable development work and accurate numerical modelling of the hinge motion was required to predict performance across a wide temperature range and ensure that during the 1st overshoot the boom did not damage itself, the harness or the spacecraft.Due to the magnetic cleanliness requirements of the spacecraft no magnetic materials could be used in the design of the hardware.

  15. Real-space imaging of non-collinear antiferromagnetic order with a single-spin magnetometer

    Science.gov (United States)

    Gross, I.; Akhtar, W.; Garcia, V.; Martínez, L. J.; Chouaieb, S.; Garcia, K.; Carrétéro, C.; Barthélémy, A.; Appel, P.; Maletinsky, P.; Kim, J.-V.; Chauleau, J. Y.; Jaouen, N.; Viret, M.; Bibes, M.; Fusil, S.; Jacques, V.

    2017-09-01

    Although ferromagnets have many applications, their large magnetization and the resulting energy cost for switching magnetic moments bring into question their suitability for reliable low-power spintronic devices. Non-collinear antiferromagnetic systems do not suffer from this problem, and often have extra functionalities: non-collinear spin order may break space-inversion symmetry and thus allow electric-field control of magnetism, or may produce emergent spin-orbit effects that enable efficient spin-charge interconversion. To harness these traits for next-generation spintronics, the nanoscale control and imaging capabilities that are now routine for ferromagnets must be developed for antiferromagnetic systems. Here, using a non-invasive, scanning single-spin magnetometer based on a nitrogen-vacancy defect in diamond, we demonstrate real-space visualization of non-collinear antiferromagnetic order in a magnetic thin film at room temperature. We image the spin cycloid of a multiferroic bismuth ferrite (BiFeO3) thin film and extract a period of about 70 nanometres, consistent with values determined by macroscopic diffraction. In addition, we take advantage of the magnetoelectric coupling present in BiFeO3 to manipulate the cycloid propagation direction by an electric field. Besides highlighting the potential of nitrogen-vacancy magnetometry for imaging complex antiferromagnetic orders at the nanoscale, these results demonstrate how BiFeO3 can be used in the design of reconfigurable nanoscale spin textures.

  16. Internal Field of Homogeneously Magnetized Toroid Sensor for Proton Free Precession Magnetometer

    DEFF Research Database (Denmark)

    Primdahl, Fritz; Merayo, José M.G.; Brauer, Peter

    2005-01-01

    The shift of the NMR spectral line frequency in a proton free precession absolute scalar magnetometer using the omni-directional toroid container for a proton-rich liquid depends on the magnetic susceptibility of the liquid and on the direction of the external field relative to the axis...... of the toroid. The theoretical shift is estimated for water by computing the additional magnetic field from the magnetization of the liquid and comparing it to the theoretical field in a spherical container. Along the axis the estimated average shift is -0.08 nT and perpendicular to the axis the shift is +0.......08 nT relative to that of a spherical sensor. The field inhomogeneity introduced by the toroid shape amounts to 0.32 nT over the volume of the sensor and is not expected to significantly affect the signal decay time, when considering the typical water line width of about 2.5 InT....

  17. Signal Conditioning for the Kalman Filter: Application to Satellite Attitude Estimation with Magnetometer and Sun Sensors.

    Science.gov (United States)

    Esteban, Segundo; Girón-Sierra, Jose M; Polo, Óscar R; Angulo, Manuel

    2016-10-31

    Most satellites use an on-board attitude estimation system, based on available sensors. In the case of low-cost satellites, which are of increasing interest, it is usual to use magnetometers and Sun sensors. A Kalman filter is commonly recommended for the estimation, to simultaneously exploit the information from sensors and from a mathematical model of the satellite motion. It would be also convenient to adhere to a quaternion representation. This article focuses on some problems linked to this context. The state of the system should be represented in observable form. Singularities due to alignment of measured vectors cause estimation problems. Accommodation of the Kalman filter originates convergence difficulties. The article includes a new proposal that solves these problems, not needing changes in the Kalman filter algorithm. In addition, the article includes assessment of different errors, initialization values for the Kalman filter; and considers the influence of the magnetic dipole moment perturbation, showing how to handle it as part of the Kalman filter framework.

  18. Airborne gamma-ray spectrometer and magnetometer survey: Susanville quadrangle, California. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Susanville, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1642.8 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  19. Magnetic measurements with a SQUID magnetometer: Possible artifacts induced by sample-holder off-centering

    Science.gov (United States)

    Casañ-Pastor, Nieves; Gomez-Romero, Pedro; Baker, Louis C. W.

    1991-04-01

    Asymmetries in sample holders used for magnetic measurements on magnetometers based on induction methods, such as those equipped with SQUID sensors, can lead to substantial errors and/or important artifacts which resemble phase transitions. They occur under the conditions for which sample and/holder have signals of opposite sign, but are nearly equal in magnitude. The most serious errors can occur often, but not exclusively, for compounds having intermediate magnetic dilution. We present here a general discussion of the problem illustrated by measurements of a polyoxometallate with the known Keggin structure K6[Fe(III)W12O40]ṡnH2O, done on a SHE VTS model 905. While one of the obvious solutions to this problem is the use of holders with a signal much smaller than that of the sample, it would be preferable if, in addition, the holder had a response of the same sign as that of the sample, for all temperatures and fields measured.

  20. Airborne gamma-ray spectrometer and magnetometer survey: Alturas quadrangle, California. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Alturas, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1631.6 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  1. Airborne gamma-ray spectrometer and magnetometer survey: Chico quadrangle, California. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Chico, California, map area. Traverse lines were flown in an east-west direction at a line spacing of three. Tie lines were flown north-south approximately twelve miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 3026.4 line miles are in the quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  2. Airborne gamma-ray spectrometer and magnetometer survey: Eureka quadrangle, California. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Eureka/Crescent City, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were aquired, compiled, and interpreted during the survey, of which 349.5 line miles are in this area. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  3. Airborne gamma-ray spectrometer and magnetometer survey: Ukiah quadrangle, California. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Ukiah, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1517 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  4. Template guided transperineal saturation biopsy of the prostate: lessons for focal and urethra-sparing high-dose-rate brachytherapy for localized prostate cancer

    Directory of Open Access Journals (Sweden)

    Sergey Nikolaevich Novikov

    2016-04-01

    Full Text Available Purpose : The aim of this work is to evaluate results of prostate transperineal saturation biopsy as a guide for focal high-dose-rate brachytherapy in patients with prostate cancer (PCa. Material and methods: Template guided saturation biopsy was performed in 67 primary patients with suspicion for prostate cancer. Biopsy was performed under ultrasonography (US control with the help of brachytherapy grid and 5 mm distance between samples. We put special attention for accurate sampling of prostate in periurethral region. The number of cores varied from 17 to 81 (average 36 cores. Finally, in 40 patients with confirmed prostate cancer results of biopsy were used for brachytherapy planning. Results : Saturation biopsy revealed prostate cancer in 40 of 67 evaluated patients. The extent of biopsy core involvement varied from 5% to 100% (average: 57%. Focal nature of PCa (single unilateral tumor nodule was diagnosed in 10 (25%, multifocal – in another 30 (75% patients. Hemigland invasion was mentioned in 12 (30% cases. Saturation biopsy detected PCa in periurethral cores in 27 (67.5% of 40 evaluated patients. In 10 patients, the extent of involvement in periurethral cores varied between 10% and 50%; in another, 17 observations exceeded 50%. According to results obtained on saturation biopsy, we performed HDR brachytherapy with “urethra low dose tunnel” (D10ur ≤ 80-90% in 13 patients with noninvolved periurethral cores. Theoretically, hemigland brachytherapy was possible in 12 of 40 evaluated patients with PCa. Conclusions : In low risk patients with PCa results of template guided saturation biopsy indicates high frequency (75% of multifocal disease and high probability (67.5% of periurethral invasion. Suitable candidates for focal HDR brachytherapy or irradiation with additional sparing of urethra can be effectively determined with the help of saturation biopsy.

  5. Conceptual design of safety injection tanks using saturated water

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hae Min; Jeong, Yong Hoon; Chang, Won Joon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2009-07-01

    Safety Injection Tanks (SITs) which is the one of Safety Injection System (SIS) play an important role in mitigating the Loss of Coolant Accidents (LOCAs) in Pressurized Water Reactor (PWR). APR1400 has the advanced 4 SITs directly connected to a reactor vessel. We expect the capacity of the SITs is getting more important since the coolant from SITs equipped with a FD during LBLOCA can replace the injection from low pressure safety injection pumps (LPSIPs). In designing a larger capacity SIT, we may have three problems; the excessively large volume for pressurized N{sub 2} gas, which is about 1/3 of the total volume, the difficulties controlling injection flowrate and the solubility of the non-condensable N{sub 2} gas in the coolant. In here, there is the contradiction which is 'there must be nitrogen gas for pressurization but there must not be nitrogen gas for more coolant.' For this problem, the axiomatic design (AD) theory enabled us to define or regularize the intrinsic problem which is termed the coupling and the contradiction. TRIZ facilitates creating solutions on the contradiction. This study proposes a conceptual design of SITs which are pressurized by steam from the saturated water as a demonstration of the conceptual design framework, AD theory and TRIZ. The purpose of this conceptual design is to increase coolant volume and to reduce N{sub 2} gas volume in SITs. In order to investigate the feasibility of the proposed design, we derived an analytical model to find the heat loss of saturated water and thermo-hydraulic safety analysis using MARS3.1. To confirm the safety and integrity of core, we conducted LBLOCA simulation to find peak cladding temperature (PCT) of design using the proposed SITs comparing with the conventional SITs. From the analysis results, the benefits of the new SIT design were observed in terms of the PCT, the quenching time and the size. And the new SIT design may enable emergency core cooling water to be injected

  6. Laboratory calibration of the seismo-acoustic response of CO2 saturated sandstones

    Science.gov (United States)

    Siggins, A. F.; Lwin, M.; Wisman, P.

    2009-04-01

    Geological sequestration can be regarded as one of the promising mitigation strategies against the negative effects of atmospheric carbon dioxide on global climate change. Injection of CO2into depleted natural gas reservoirs in particular, sandstone formations at depth with suitable porosity and seals, seems to be a promising scenario for on-land storage. In fact, a demonstration project is currently underway in the Otway Basin in South Eastern Australia under the auspices of the Australian CO2CRC. One of the most useful geophysical remote sensing tools for monitoring sub surface CO2 injection is seismic imaging. Interpretation of seismic data for the quantitative measurement of the distribution and saturations of CO2 in the subsurface requires a knowledge of the effects of CO2as a pore fluid on the seismo-acoustic response of the reservoir rocks. This report describes some recent experiments that we have conducted to investigate this aspect under controlled laboratory conditions at pressures representative of in-situ reservoir conditions. Prior to the availability of core from the actual Otway injection site, two synthetic sandstones were tested ultrasonically in a computer controlled triaxial testing rig under a range of confining pressures and pore pressures representative of in-situ reservoir pressures. These sandstones comprised; (1) a synthetic material with calcite intergranular cement (CIPS) and (2), a synthetic sandstone with silica intergranular cement. Porosities of the sandstones were respectively, 32%,and 33%. Initial testing was carried on the cores at room temperature-dried condition with confining pressures up to 65MPa in steps of 5 MPa. Cores were then flooded with CO2, initially at 6MPa, 22 degrees C, then with liquid phase CO2at pressures from 7MPa to 17 MPa in steps of 5 MPa. Confining pressures varied from 10 MPa to 65 MPa. A limited number of experiments were also conducted in an additional rig at 50oC with supercritical phase CO2. Ultrasonic

  7. PLD-grown thin film saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Tellkamp, Friedjof

    2012-11-01

    The subject of this thesis is the preparation and characterization of thin films made of oxidic dielectrics which may find their application as saturable absorber in passively Q-switched lasers. The solely process applied for fabrication of the thin films was the pulsed laser deposition (PLD) which stands out against other processes by its flexibility considering the composition of the systems to be investigated. Within the scope of this thesis the applied saturable absorbers can be divided into two fundamentally different kinds of functional principles: On the one hand, saturable absorption can be achieved by ions embedded in a host medium. Most commonly applied bulk crystals are certain garnets like YAG (Y{sub 3}Al{sub 5}O{sub 12}) or the spinel forsterite (Mg{sub 2}SiO{sub 4}), in each case with chromium as dopant. Either of these media was investigated in terms of their behavior as PLD-grown saturable absorber. Moreover, experiments with Mg{sub 2}GeO{sub 4}, Ca{sub 2}GeO{sub 4}, Sc{sub 2}O{sub 3}, and further garnets like YSAG or GSGG took place. The absorption coefficients of the grown films of Cr{sup 4+}:YAG were determined by spectroscopic investigations to be one to two orders of magnitude higher compared to commercially available saturable absorbers. For the first time, passive Q-switching of a Nd:YAG laser at 1064 nm with Cr{sup 4+}:YAG thin films could be realized as well as with Cr:Sc{sub 2}O{sub 3} thin films. On the other hand, the desirable effect of saturable absorption can also be generated by quantum well structures. For this purpose, several layer system like YAG/LuAG, Cu{sub 2}O/MgO, and ZnO/corumdum were investigated. It turned out that layer systems with indium oxide (In{sub 2}O{sub 3}) did not only grew in an excellent way but also showed up a behavior regarding their photo luminescence which cannot be explained by classical considerations. The observed luminescence at roughly 3 eV (410 nm) was assumed to be of excitonic nature and its

  8. Making Mercury's Core with Light Elements

    Science.gov (United States)

    Vander Kaaden, Kathleen E.; McCubbin, Francis M.; Ross, D. Kent

    2016-01-01

    Recent results obtained from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft showed the surface of Mercury has low FeO abundances (less than 2 wt%) and high S abundances (approximately 4 wt%), suggesting the oxygen fugacity of Mercury's surface materials is somewhere between 3 to 7 log10 units below the IW buffer. The highly reducing nature of Mercury has resulted in a relatively thin mantle and a large core that has the potential to exhibit an exotic composition in comparison to the other terrestrial planets. This exotic composition may extend to include light elements (e.g., Si, C, S). Furthermore, has argued for a possible primary floatation crust on Mercury composed of graphite, which may require a core that is C-saturated. In order to investigate mercurian core compositions, we conducted piston cylinder experiments at 1 GPa, from 1300 C to 1700 C, using a range of starting compositions consisting of various Si-Fe metal mixtures (Si5Fe95, Si10Fe90, Si22Fe78, and Si35Fe65). All metals were loaded into graphite capsules used to ensure C-saturation during the duration of each experimental run. Our experiments show that Fe-Si metallic alloys exclude carbon relative to more Fe-rich metal. This exclusion of carbon commences within the range of 5 to 10 wt% Si. These results indicate that if Mercury has a Si-rich core (having more than approximately 5 wt% silicon), it would have saturated in carbon at low C abundances allowing for the possible formation of a graphite floatation crust as suggested by. These results have important implications for the thermal and magmatic evolution of Mercury.

  9. Trans Fat Now Listed With Saturated Fat and Cholesterol

    Science.gov (United States)

    ... Trans Fat Now Listed With Saturated Fat and Cholesterol Share Tweet Linkedin Pin it More sharing options ... I Do About Saturated Fat, Trans Fat, and Cholesterol? When comparing foods, look at the Nutrition Facts ...

  10. Calcium phosphate saturation in the western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.; Reddy, C.V.G.

    Temperature, inorganic phosphate concentration and pH seem to be the major factors influencing the degree of saturation of calcium phosphate in sea water. Two water regions can be demarcated in the study area based on the saturation patterns...

  11. Nonmonotone Saturation Profiles for Hydrostatic Equilibrium in Homogeneous Porous Media

    NARCIS (Netherlands)

    Hilfer, R.; Doster, F.; Zegeling, P.A.|info:eu-repo/dai/nl/073634433

    2012-01-01

    Nonmonotonic saturation profiles (saturation overshoot) occur as travelling waves in gravity driven fingering. They seem important for preferential flow mechanisms and have found much attention recently. Here, we predict them even for hydrostatic equilibrium when all velocities vanish. We suggest

  12. Heavy Flavor Production in DGLAP improved Saturation Model

    CERN Document Server

    Sapeta, S

    2007-01-01

    The saturation model with DGLAP evolution is shown to give good description of the production of the charm and beauty quarks in deep inelastic scattering. The modifications of saturation properties caused by the presence of heavy quarks are also discussed.

  13. Rigid aleph_epsilon-saturated models of superstable theories

    OpenAIRE

    Shami, Ziv; Shelah, Saharon

    1999-01-01

    In a countable superstable NDOP theory, the existence of a rigid aleph_epsilon-saturated model implies the existence of 2^lambda rigid aleph_epsilon-saturated models of power lambda for every lambda>2^{aleph_0}.

  14. Silica fractal atomic clusters saturated with OH

    CERN Document Server

    Olivi-Tran, N

    2003-01-01

    We constructed regular fractal SiOH atomic clusters which pending bonds are saturated with OH molecules. We calculated the binding energies of these clusters as well as for sp sup 2 hybridization as for sp sup 3 hybridizations. The result are the following: for the two hybridizations, the total binding energies have a linear dependence on the size of the fractal cluster, which comes directly from the scaling law of the fractal characteristic of the building of the cluster. We related by a scaling law, the number of electronic bonds and the total bonding energy.

  15. Chloride diffusion in partially saturated cementitious material

    DEFF Research Database (Denmark)

    Nielsen, Erik Pram; Geiker, Mette Rica

    2003-01-01

    The paper proposes a combined application of composite theory and Powers' model for microstructural development for the estimation of the diffusion coefficient as a function of the moisture content of a defect-free cementitious material. Measurements of chloride diffusion in mortar samples (440 kg....../m(3) rapid-hardening Portland cement, w/c = 0.5, maturity minimum 6 months) stored at 65% and 85% RH, as well as in vacuum-saturated mortar samples, illustrate the applicability of the method. (C) 2003 Elsevier Science Ltd. All rights reserved....

  16. THE PROGNOSTIC AND DIAGNOSTIC VALUE OF REPEATED TRANSRECTAL PROSTATE SATURATION BIOPSY

    Directory of Open Access Journals (Sweden)

    M. A. Kurdzhiev

    2014-08-01

    Full Text Available Objective: to determine the rate of prostate cancer (PC development after repeated transrectal saturation prostate biopsy (RTRSPB, to study the characteristics of diagnosed tumors, and to estimate their clinical significance from the data of radical retropubic prostatectomy (RRP.Materials and methods. The results of RTRSPB were analyzed in 226 patients with a later evaluation of a tumor from the results of RRP. All the patients underwent at least 2 prostate biopsies (mean 2.4. The average number of biopsy cores was 26.7 (range 24—30. The average value of total prostate-specific antigen before saturation biopsy was 7.5 (range 7.5 to 28.6 ng/ml. The mean age of patients was 62 years (range 53 to 70.  Results. PC was diagnosed in 14.6% of cases (33/226. An isolated lesion of the prostatic transition zone was in 12.1% of cases. If this zone had been excluded from the biopsy scheme, the detection rate of PC during saturation biopsy should be reduced by 13.8%. Better PC detectability during repeated saturation biopsy generally occurred due to the localized forms of the disease (93.3%. The agreement of Gleason tumor grading in the biopsy and prostatectomy specimens was noted in 66.7% of cases.Conclusion. Saturation biopsy allows prediction of a pathological stage of PC, Gleason grade of a tumor and its site localization with a greater probability. Most tumors detectable by saturation biopsy were clinically significant, which makes it possible to recommend RTRSPB to some cohort of high PC-risk patients 

  17. The presence of prostate cancer on saturation biopsy can be accurately predicted.

    Science.gov (United States)

    Ahyai, Sascha A; Isbarn, Hendrik; Karakiewicz, Pierre I; Chun, Felix K H; Reichert, Mathias; Walz, Jochen; Steuber, Thomas; Jeldres, Claudio; Schlomm, Thorsten; Heinzer, Hans; Salomon, Georg; Budäus, Lars; Perrotte, Paul; Huland, Hartwig; Graefen, Markus; Haese, Alexander

    2010-03-01

    To improve the ability of our previously reported saturation biopsy nomogram quantifying the risk of prostate cancer, as the use of office-based saturation biopsy has increased. Saturation biopsies of 540 men with one or more previously negative 6-12 core biopsies were used to develop a multivariable logistic regression model-based nomogram, predicting the probability of prostate cancer. Candidate predictors were used in their original or stratified format, and consisted of age, total prostate-specific antigen (PSA) level, percentage free PSA (%fPSA), gland volume, findings on a digital rectal examination, cumulative number of previous biopsy sessions, presence of high-grade prostatic intraepithelial neoplasia on any previous biopsy, and presence of atypical small acinar proliferation (ASAP) on any previous biopsy. Two hundred bootstraps re-samples were used to adjust for overfit bias. Prostate cancer was diagnosed in 39.4% of saturation biopsies. Age, total PSA, %fPSA, gland volume, number of previous biopsies, and presence of ASAP at any previous biopsy were independent predictors for prostate cancer (all P < 0.05). The nomogram was 77.2% accurate and had a virtually perfect correlation between predicted and observed rates of prostate cancer. We improved the accuracy of the saturation biopsy nomogram from 72% to 77%; it relies on three previously included variables, i.e. age, %fPSA and prostate volume, and on three previously excluded variables, i.e. PSA, the number of previous biopsy sessions, and evidence of ASAP on previous biopsy. Our study represents the largest series of saturation biopsies to date.

  18. Inheritance of reduced saturated fatty acid content in sunflower oil

    OpenAIRE

    Vick Brady A.; Jan C.C.; Miller Jerry F.

    2002-01-01

    In recent years, consumers have become concerned with reducing the saturated fat content of their diet. Studies have indicated that high levels of saturated fat consumption are correlated with increased risk of coronary heart disease. The total saturated fat content of oil from current sunflower hybrids averages about 130 g kg-1. To identify sunflower germplasm with reduced saturated fatty acid composition, a total of 884 cultivated sunflower accessions from the USDA-ARS North Central Regiona...

  19. Test of Scintillometer Saturation Correction Methods Using Field Experimental Data

    NARCIS (Netherlands)

    Kleissl, J.; Hartogensis, O.K.; Gomez, J.D.

    2010-01-01

    Saturation of large aperture scintillometer (LAS) signals can result in sensible heat flux measurements that are biased low. A field study with LASs of different aperture sizes and path lengths was performed to investigate the onset of, and corrections for, signal saturation. Saturation already

  20. A demonstration experiment for studying the properties of saturated vapor

    Science.gov (United States)

    Grebenev, Igor V.; Lebedeva, Olga V.; Polushkina, Svetlana V.

    2017-11-01

    The paper proposes an important demonstration experiment that can be used at secondary schools in physics. The described experiment helps students learn the main concepts of the topic ‘saturated vapor’, namely, evaporation, condensation, dynamic equilibrium, saturation vapor, partial pressure, and the dependence of saturated vapor pressure on temperature.

  1. Nonlinear saturation of the Rayleigh instability due to oscillatory flow in a liquid-lined tube

    Science.gov (United States)

    Halpern, David; Grotberg, James B.

    2003-10-01

    In this paper, the stability of core annular flows consisting of two immiscible fluids in a cylindrical tube with circular cross-section is examined. Such flows are important in a wide range of industrial and biomedical applications. For example, in secondary oil recovery, water is pumped into the well to displace the remaining oil. It is also of relevance in the lung, where a thin liquid film coats the inner surface of the small airways of the lungs. In both cases, the flow is influenced by a surface-tension instability, which may induce the breakup of the core fluid into short plugs, reducing the efficiency of the oil recovery, or blocking the passage of air in the lung thus inducing airway closure. We consider the stability of a thin film coating the inner surface of a rigid cylindrical tube with the less viscous fluid in the core. For thick enough films, the Rayleigh instability forms a liquid bulge that can grow to eventually create a plug blocking the tube. The analysis explores the effect of an oscillatory core flow on the interfacial dynamics and particularly the nonlinear stabilization of the bulge. The oscillatory core flow exerts tangential and normal stresses on the interface between the two fluids that are simplified by uncoupling the core and film analyses in the thin-film high-frequency limit of the governing equations. Lubrication theory is used to derive a nonlinear evolution equation for the position of the air liquid interface which includes the effects of the core flow. It is shown that the core flow can prevent plug formation of the more viscous film layer by nonlinear saturation of the capillary instability. The stabilization mechanism is similar to that of a reversing butter knife, where the core shear wipes the growing liquid bulge back on to the tube wall during the main tidal volume stroke, but allows it to grow back as the stoke and shear turn around. To be successful, the leading film thickness ahead of the bulge must be smaller than the

  2. Passively Q-switched erbium-doped fiber laser based on Zn nanoparticles as a saturable absorber

    Science.gov (United States)

    Zaca-Morán, P.; Ortega-Mendoza, J. G.; Lozano-Perera, G. J.; Gómez-Pavón, L. C.; Pérez-Sánchez, G. F.; Padilla-Martínez, J. P.; Felipe, C.

    2017-10-01

    In this work, a passively Q-switched erbium-doped ring laser using zinc nanoparticles as a saturable absorber is studied and experimentally demonstrated. To achieve this, a saturable absorber was developed through a selective incorporation of zinc nanoparticles onto the core of an optical fiber using a coherent light source of an infrared laser at 1550 nm, then the saturable absorber was inserted into a laser cavity. The laser has a threshold pump power of 57.7 mW at 980 nm, and a range of pulse-repetition rate from 12.3 to 43 kHz. The highest pulse energy of 2.6 nJ was obtained at a repetition rate of 43 kHz and an output wavelength of 1565.5 nm. In addition, the saturable absorber was morphologically characterized by using both scanning electron and atomic force microscopy showing a uniform distribution of nanoparticles deposited on the optical fiber core. This is, to the best of our knowledge, the first demonstration of a Q-switched fiber laser using Zn nanoparticles as a device of saturable absorption.

  3. SITE-SCALE SATURATED ZONE TRANSPORT

    Energy Technology Data Exchange (ETDEWEB)

    S. KELLER

    2004-11-03

    This work provides a site-scale transport model for calculating radionuclide transport in the saturated zone (SZ) at Yucca Mountain, for use in the abstractions model in support of ''Total System Performance Assessment for License Application'' (TSPA-LA). The purpose of this model report is to provide documentation for the components of the site-scale SZ transport model in accordance with administrative procedure AP-SIII.10Q, Models. The initial documentation of this model report was conducted under the ''Technical Work Plan For: Saturated Zone Flow and Transport Modeling and Testing'' (BSC 2003 [DIRS 163965]). The model report has been revised in accordance with the ''Technical Work Plan For: Natural System--Saturated Zone Analysis and Model Report Integration'', Section 2.1.1.4 (BSC 2004 [DIRS 171421]) to incorporate Regulatory Integration Team comments. All activities listed in the technical work plan that are appropriate to the transport model are documented in this report and are described in Section 2.1.1.4 (BSC 2004 [DIRS 171421]). This report documents: (1) the advection-dispersion transport model including matrix diffusion (Sections 6.3 and 6.4); (2) a description and validation of the transport model (Sections 6.3 and 7); (3) the numerical methods for simulating radionuclide transport (Section 6.4); (4) the parameters (sorption coefficient, Kd ) and their uncertainty distributions used for modeling radionuclide sorption (Appendices A and C); (5) the parameters used for modeling colloid-facilitated radionuclide transport (Table 4-1, Section 6.4.2.6, and Appendix B); and (6) alternative conceptual models and their dispositions (Section 6.6). The intended use of this model is to simulate transport in saturated fractured porous rock (double porosity) and alluvium. The particle-tracking method of simulating radionuclide transport is incorporated in the finite-volume heat and mass transfer numerical

  4. k -core covers and the core

    NARCIS (Netherlands)

    Sanchez-Rodriguez, E.; Borm, P.; Estevez Fernandez, M.A.; Fiestras-Janeiro, M.G.; Mosquera, M.A.

    2015-01-01

    This paper extends the notion of individual minimal rights for a transferable utility game (TU-game) to coalitional minimal rights using minimal balanced families of a specific type, thus defining a corresponding minimal rights game. It is shown that the core of a TU-game coincides with the core of

  5. k-core covers and the core

    NARCIS (Netherlands)

    Sanchez-Rodriguez, E.; Borm, Peter; Estevez-Fernandez, A.; Fiestras-Janeiro, G.; Mosquera, M.A.

    This paper extends the notion of individual minimal rights for a transferable utility game (TU-game) to coalitional minimal rights using minimal balanced families of a specific type, thus defining a corresponding minimal rights game. It is shown that the core of a TU-game coincides with the core of

  6. Structure and Performance Characteristics of Saturated Iron-core Superconducting Fault Current Limiter

    National Research Council Canada - National Science Library

    Niu, Xiaoye; Chen, Zhili; Wang, Haizhen; Chen, Zhifu; Zhang, Lifeng; Niu, Guojun; Hong, Hui; Xin, Ying

    2014-01-01

    .... The immediately reacting and fast recovering are also its main characteristics. The structure and function of SISFCL is similar to that of traditional transformer and current limiting reactor respectively...

  7. Reactive/Adsorptive transport in (partially-) saturated porous media: from pore scale to core scale

    NARCIS (Netherlands)

    Raoof, A.

    2011-01-01

    Pore-scale modeling provides opportunities to study transport phenomena in fundamental ways because detailed information is available at the microscopic pore scale. This offers the best hope for bridging the traditional gap that exists between pore scale and macro (lab) scale description of the

  8. Meridian-scanning photometer, coherent HF radar, and magnetometer observations of the cusp: a case study

    Directory of Open Access Journals (Sweden)

    S. E. Milan

    1999-02-01

    Full Text Available The dynamics of the cusp region and post-noon sector for an interval of predominantly IMF By, Bz < 0 nT are studied with the CUTLASS Finland coherent HF radar, a meridian-scanning photometer located at Ny Ålesund, Svalbard, and a meridional network of magnetometers. The scanning mode of the radar is such that one beam is sampled every 14 s, and a 30° azimuthal sweep is completed every 2 minutes, all at 15 km range resolution. Both the radar backscatter and red line (630 nm optical observations are closely co-located, especially at their equatorward boundary. The optical and radar aurora reveal three different behaviours which can interchange on the scale of minutes, and which are believed to be related to the dynamic nature of energy and momentum transfer from the solar wind to the magnetosphere through transient dayside reconnection. Two interpretations of the observations are presented, based upon the assumed location of the open/closed field line boundary (OCFLB. In the first, the OCFLB is co-located with equatorward boundary of the optical and radar aurora, placing most of the observations on open field lines. In the second, the observed aurora are interpreted as the ionospheric footprint of the region 1 current system, and the OCFLB is placed near the poleward edge of the radar backscatter and visible aurora; in this interpretation, most of the observations are placed on closed field lines, though transient brightenings of the optical aurora occur on open field lines. The observations reveal several transient features, including poleward and equatorward steps in the observed boundaries, "braiding" of the backscatter power, and 2 minute quasi-periodic enhancements of the plasma drift and optical intensity, predominantly on closed field lines.Key words. Ionosphere (auroral ionosphere; plasma convection · Magnetospheric physics (magnetopause · cusp · and boundary layers

  9. On the Potential of a New Generation of Magnetometers for MEG: A Beamformer Simulation Study.

    Directory of Open Access Journals (Sweden)

    Elena Boto

    Full Text Available Magnetoencephalography (MEG is a sophisticated tool which yields rich information on the spatial, spectral and temporal signatures of human brain function. Despite unique potential, MEG is limited by a low signal-to-noise ratio (SNR which is caused by both the inherently small magnetic fields generated by the brain, and the scalp-to-sensor distance. The latter is limited in current systems due to a requirement for pickup coils to be cryogenically cooled. Recent work suggests that optically-pumped magnetometers (OPMs might be a viable alternative to superconducting detectors for MEG measurement. They have the advantage that sensors can be brought to within ~4 mm of the scalp, thus offering increased sensitivity. Here, using simulations, we quantify the advantages of hypothetical OPM systems in terms of sensitivity, reconstruction accuracy and spatial resolution. Our results show that a multi-channel whole-head OPM system offers (on average a fivefold improvement in sensitivity for an adult brain, as well as clear improvements in reconstruction accuracy and spatial resolution. However, we also show that such improvements depend critically on accurate forward models; indeed, the reconstruction accuracy of our simulated OPM system only outperformed that of a simulated superconducting system in cases where forward field error was less than 5%. Overall, our results imply that the realisation of a viable whole-head multi-channel OPM system could generate a step change in the utility of MEG as a means to assess brain electrophysiological activity in health and disease. However in practice, this will require both improved hardware and modelling algorithms.

  10. Origin of the SuperDARN broad Doppler spectra:simultaneous observation with Oersted satellite magnetometer

    Directory of Open Access Journals (Sweden)

    K. Hosokawa

    2004-01-01

    Full Text Available We perform a case study of a favorable conjunction of an overpass of the Oersted satellite with the field-of-view of the SuperDARN Syowa East radar during an interval of the southward IMF Bz. At the time, the radar observed an L-shell aligned boundary in the spectral width around the dayside ionosphere. Simultaneously, high-frequency (0.2–5Hz magnetic field fluctuations were observed by the Oersted satellite's high-time resolution magnetometer. These magnetic field fluctuations are considered to be Alfvén waves possibly associated with the particle which precipitates into the dayside high-latitude ionosphere when magnetic reconnection occurs. It has been theoretically predicted that the time-varying electric field is the dominant physical process to expand the broad HF radar Doppler spectra. Our observation clearly demonstrates that the boundary between narrow and broad spectral widths is corresponding well to the boundary in the level of the fluctuations, which supports the previous theoretical prediction. A close relationship between electric and magnetic field fluctuations and particle precipitations during southward IMF conditions has been confirmed by many authors. The present observation allows us to suggest that the boundary between narrow and broad Doppler spectral widths observed in the dayside ionosphere is connected with the signature of the open/closed field line boundary, such as the cusp particle precipitations via electric and magnetic field fluctuations for the case of the negative IMF Bz conditions. Key words. Ionosphere (ionosphere-magnetosphere interactions; plasma convection. Magnetospheric physics (magnetopause, cusp, and boundary layers

  11. Origin of the SuperDARN broad Doppler spectra:simultaneous observation with Oersted satellite magnetometer

    Directory of Open Access Journals (Sweden)

    K. Hosokawa

    2004-01-01

    Full Text Available We perform a case study of a favorable conjunction of an overpass of the Oersted satellite with the field-of-view of the SuperDARN Syowa East radar during an interval of the southward IMF Bz. At the time, the radar observed an L-shell aligned boundary in the spectral width around the dayside ionosphere. Simultaneously, high-frequency (0.2–5Hz magnetic field fluctuations were observed by the Oersted satellite's high-time resolution magnetometer. These magnetic field fluctuations are considered to be Alfvén waves possibly associated with the particle which precipitates into the dayside high-latitude ionosphere when magnetic reconnection occurs. It has been theoretically predicted that the time-varying electric field is the dominant physical process to expand the broad HF radar Doppler spectra. Our observation clearly demonstrates that the boundary between narrow and broad spectral widths is corresponding well to the boundary in the level of the fluctuations, which supports the previous theoretical prediction. A close relationship between electric and magnetic field fluctuations and particle precipitations during southward IMF conditions has been confirmed by many authors. The present observation allows us to suggest that the boundary between narrow and broad Doppler spectral widths observed in the dayside ionosphere is connected with the signature of the open/closed field line boundary, such as the cusp particle precipitations via electric and magnetic field fluctuations for the case of the negative IMF Bz conditions.

    Key words. Ionosphere (ionosphere-magnetosphere interactions; plasma convection. Magnetospheric physics (magnetopause, cusp, and boundary layers

  12. Cognitive zonal fusion biopsy of the prostate: Original technique between target and saturation

    Directory of Open Access Journals (Sweden)

    Andrea B. Galosi

    2016-12-01

    Full Text Available We describe our experience in prostate biopsy using a new standardized cognitive fusion techniques, that we call “cognitive zonal fusion biopsy”. This new technique is based on two operative options: the first based on target biopsies, the Cognitive Target Biopsy (CTB if the same target was detected with transrectal ultrasound (TRUS and multiparametric magnetic resonance (mpMRI; the second based on saturation biopsies, the Zonal Saturation Biopsy (ZSB on anatomical zone/s containing the region of interest if the same target was not evident with TRUS and MRI. We evaluated results of our technique compared to standard biopsy in order to identify clinically relevant prostate cancer. Methods: This is a single-center prospective study conducted in 58 pts: 25 biopsy-naïve, 25 with previous negative biopsy and in 8 with cancer in active surveillance. Based on mpMRI and transrectal ultrasonography (TRUS, all patients were scheduled for standard 12-core TRUS-guided biopsy. If mpMRI was suggestive or positive (PI-RADS 3, 4 or 5: patients underwent additional targeted 2 to 6 cores using cognitive zonal fusion technique. Results: 31/58 (53.4% patients had a cancer. Our technique detected 80.6% (25 of 31 with clinically significant prostate cancer, leading to detection of insignificant cancer in 20%. Using standard mapping in MR negative areas we found 5 clinically significant cancer and 4 not significant cancers. MRI cancer detection rate was 18/31 (58.1%, and 9/18 (50% in high grade tumors. Therefore MRI missed 50% of high grade cancers. The mean number of cores taken with cognitive zonal fusion biopsy was 6.1 (2-17, in addition biopsy sampling was done outside the ROI areas. Overall 15.4 cores (12-22 were taken. Cancer amount in Zonal Biopsy was larger than 7.3 mm (1-54.5 in comparison with 5.2 mm (1-23.5 in standard mapping. Largest percentage of cancer involvement with cognitive zonal fusion technique was detected in 19.4% vs 15.9%. Conclusions

  13. Optical frequency standard using acetylene-filled hollow-core photonic crystal fibers

    DEFF Research Database (Denmark)

    Triches, Marco; Michieletto, Mattia; Hald, Jan

    2015-01-01

    Gas-filled hollow-core photonic crystal fibers are used to stabilize a fiber laser to the 13C2H2 P(16) (ν1+ν3) transition at 1542 nm using saturated absorption. Four hollow-core fibers with different crystal structure are compared in terms of long term lock-point repeatability and fractional freq...

  14. Energy dependent saturable and reverse saturable absorption in cube-like polyaniline/polymethyl methacrylate film

    Energy Technology Data Exchange (ETDEWEB)

    Thekkayil, Remyamol [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India); Philip, Reji [Light and Matter Physics Group, Raman Research Institute, C.V. Raman Avenue, Bangalore 560 080 (India); Gopinath, Pramod [Department of Physics, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India); John, Honey, E-mail: honey@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India)

    2014-08-01

    Solid films of cube-like polyaniline synthesized by inverse microemulsion polymerization method have been fabricated in a transparent PMMA host by an in situ free radical polymerization technique, and are characterized by spectroscopic and microscopic techniques. The nonlinear optical properties are studied by open aperture Z-scan technique employing 5 ns (532 nm) and 100 fs (800 nm) laser pulses. At the relatively lower laser pulse energy of 5 μJ, the film shows saturable absorption both in the nanosecond and femtosecond excitation domains. An interesting switchover from saturable absorption to reverse saturable absorption is observed at 532 nm when the energy of the nanosecond laser pulses is increased. The nonlinear absorption coefficient increases with increase in polyaniline concentration, with low optical limiting threshold, as required for a good optical limiter. - Highlights: • Synthesized cube-like polyaniline nanostructures. • Fabricated polyaniline/PMMA nanocomposite films. • At 5 μJ energy, saturable absorption is observed both at ns and fs regime. • Switchover from SA to RSA is observed as energy of laser beam increases. • Film (0.1 wt % polyaniline) shows high β{sub eff} (230 cm GW{sup −1}) and low limiting threshold at 150 μJ.

  15. Femoral venous oxygen saturation and central venous oxygen saturation in critically ill patients.

    Science.gov (United States)

    Zhang, Xiaohong; Wang, Jiandong; Dong, Yun; Chen, Youdai

    2015-08-01

    To investigate the relationship between central venous oxygen saturation (ScvO(2)) and femoral venous oxygen saturation (SfvO(2)) in a large group of critically ill patients. Observational study. A group of unselected critically ill patients with central line placed into superior vena cava were included. A 26-bed intensive care unit in a tertiary referral hospital. None. Venous blood samples of superior vena cava and femoral vein were collected within an interval of 5 to 15 minutes and analyzed with blood gas/electrolyte analyzer immediately. Although SfvO(2) was significantly correlated with ScvO(2) (r = 0.493, P 731 pairs of blood samples collected from 357 patients. The fit line of scatter diagram ScvO(2) vs SfvO(2) had a large intercept (48.68%) and a low slope (0.2978); ScvO(2) was still around 50% while SfvO(2) was nearing 0%. The distribution of blood flow, measured with Doppler ultrasound, had a similar trend in 237 patients and 412 measurements. The ratio of femoral artery flow over common carotid artery flow varied widely (from 0 to 7.13). Blood flow was not distributed in a fixed ratio to the superior vena cava-drained organs and tissues. Central venous oxygen saturation was not representative of the whole systemic circulation in critically ill patients. Central venous oxygen saturation alone might be misleading in goal-directed therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Speed control of switched reluctance motors taking into account mutual inductances and magnetic saturation effects

    Energy Technology Data Exchange (ETDEWEB)

    Alrifai, M., E-mail: alrifm@eng.kuniv.edu.k [Electrical Engineering Department, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, Safat 13060 (Kuwait); Zribi, M.; Rayan, M. [Electrical Engineering Department, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, Safat 13060 (Kuwait); Krishnan, R. [Center for Rapid Transit Systems, Electrical and Computer Engineering Department, Virginia Tech University, 461 Durham Hall, Blacksburg, VA 24061-011 (United States)

    2010-06-15

    This paper deals with the speed control of switched reluctance motor (SRM) drives taking into account the effects of the mutual inductances between two adjacent phases and the effects of the magnetic saturation of the core. To overcome the problems commonly associated with single-phase excitation, a nonlinear SRM model, which is suitable for two-phase excitation and which takes into account the effects of mutual inductances between two adjacent phases and the magnetic saturation effects, is considered in the design of the proposed controllers. A feedback linearization control scheme and a sliding mode control scheme are designed for this motor drive. The proposed controllers guarantee the convergence of the phase currents and the rotor speed of the motor to their desired values. Simulation results indicate that the proposed controllers work well and that they are robust to changes in the parameters of the system and to changes in the load torque.

  17. A sulfide-saturated lunar mantle?

    Science.gov (United States)

    Brenan, James M.; Mungall, James E.

    2017-04-01

    Although much work has been done to understand the controls on the sulfur content at sulfide saturation (SCSS) for terrestrial melt compositions, little information exists to evaluate the SCSS for the high FeO compositions typical of lunar magmas, and at the reduced conditions of the Moon's interior. Experiments were done to measure the SCSS for a model low Ti mare basalt with 20 wt% FeO at 1400oC as a function of fO2 and pressure. Synthetic lunar basalt was encapsulated along with stoichiometric FeS in capsules made from Fe-Ir alloy. The fO2 of the experiment can be estimated by the heterogeneous equilibrium: Femetal + 1 /2 O2 = FeOsilicate Variation in the metal composition, by addition of Ir, serves to change the fO2 of the experiment. Capsule compositions spanning the range Fe25Ir75 to Fe96Ir4 (at%) were synthesized by sintering of pressed powders under reducing conditions. Fe100 capsules were fabricated from pure Fe rod. For a melt with 20 wt% FeO, this range in capsule composition spans the fO2 interval of ˜IW-1 (Fe100, Fe96Ir4) to IW+2.2 (Fe25Ir75). Experiments were done over the pressure interval of 0.1 MPa to 2 GPa. Results for experiments involving Fe100capsules indicate that the SCSS decreases from ˜2000 ppm (0.1 MPa) to 700 ppm (2 GPa). Experiments done thus far at 1 GPa, involving the range of capsule compositions indicated, show a marked decrease in SCSS as the Fe content of the capsule increases (fO2 decreases). Complementary to the decrease in SCSS is a drop in the sulfur content of the coexisting sulfide melt, from ˜50 at% at ΔIW = +2.2 to ˜20 at% at ΔIW-1. In fact, both the composition of the sulfide melt and the SCSS are essentially indistinguishable for Fe96Ir4 and Fe100 compositions. Results thus far indicate that at reduced conditions and high pressure, the SCSS for high FeO lunar compositions is low, and overlaps with Apollo 11 melt inclusion data. Importantly, such low SCSS does not require Fe metal saturation, and suggests that some

  18. From QCD to nuclear matter saturation

    Energy Technology Data Exchange (ETDEWEB)

    Ericson, Magda [Universite de Lyon, Univ. Lyon 1, CNRS/IN2P3, IPN Lyon, F-69622 Villeurbanne Cedex (France)]|[Theory division, CERN, CH-12111 Geneva (Switzerland); Chanfray, Guy [Universite de Lyon, Univ. Lyon 1, CNRS/IN2P3, IPN Lyon, F-69622 Villeurbanne Cedex (France)

    2007-03-15

    We discuss a relativistic chiral theory of nuclear matter with {sigma} and {omega} exchange using a formulation of the {sigma} model in which all the chiral constraints are automatically fulfilled. We establish a relation between the nuclear response to the scalar field and the QCD one which includes the nucleonic parts. It allows a comparison between nuclear and QCD information. Going beyond the mean field approach we introduce the effects of the pion loops supplemented by the short-range interaction. The corresponding Landau-Migdal parameters are taken from spin-isospin physics results. The parameters linked to the scalar meson exchange are extracted from lattice QCD results. These inputs lead to a reasonable description of the saturation properties, illustrating the link between QCD and nuclear physics. We also derive from the corresponding equation of state the density dependence of the quark condensate and of the QCD susceptibilities. (authors)

  19. The Danish tax on saturated fat

    DEFF Research Database (Denmark)

    Jensen, Jørgen Dejgård; Smed, Sinne

    2013-01-01

    Denmark introduced a new tax on saturated fat in food products with effect from October 2011. The objective of this paper is to make an effect assessment of this tax for some of the product categories most significantly affected by the new tax, namely fats such as butter, butter-blends, margarine...... fat in food products has had some effects on the market for the considered products, in that the level of consumption of fats dropped by 10 – 20%. Furthermore, the analysis points at shifts in demand from high-price supermarkets towards low-price discount stores – at least for some types of oils...... and fats, a shift that seems to have been utilized by discount chains to raise the prices of butter and margarine by more than the pure tax increase. Due to the relatively short data period with the tax being active, interpretation of these findings from a long-run perspective should be done...

  20. Integrated petrophysical and reservoir characterization workflow to enhance permeability and water saturation prediction

    Science.gov (United States)

    Al-Amri, Meshal; Mahmoud, Mohamed; Elkatatny, Salaheldin; Al-Yousef, Hasan; Al-Ghamdi, Tariq

    2017-07-01

    Accurate estimation of permeability is essential in reservoir characterization and in determining fluid flow in porous media which greatly assists optimize the production of a field. Some of the permeability prediction techniques such as Porosity-Permeability transforms and recently artificial intelligence and neural networks are encouraging but still show moderate to good match to core data. This could be due to limitation to homogenous media while the knowledge about geology and heterogeneity is indirectly related or absent. The use of geological information from core description as in Lithofacies which includes digenetic information show a link to permeability when categorized into rock types exposed to similar depositional environment. The objective of this paper is to develop a robust combined workflow integrating geology and petrophysics and wireline logs in an extremely heterogeneous carbonate reservoir to accurately predict permeability. Permeability prediction is carried out using pattern recognition algorithm called multi-resolution graph-based clustering (MRGC). We will bench mark the prediction results with hard data from core and well test analysis. As a result, we showed how much better improvements are achieved in the permeability prediction when geology is integrated within the analysis. Finally, we use the predicted permeability as an input parameter in J-function and correct for uncertainties in saturation calculation produced by wireline logs using the classical Archie equation. Eventually, high level of confidence in hydrocarbon volumes estimation is reached when robust permeability and saturation height functions are estimated in presence of important geological details that are petrophysically meaningful.

  1. Direct determination of IMF B-Y-related cusp current systems, using SuperDARN radar and multiple ground magnetometer data: A link to theory on cusp current origin

    DEFF Research Database (Denmark)

    Amm, O.; Engebretson, M.J.; Greenwald, R.A.

    1999-01-01

    We analyze an ionospheric "enhanced convection event" in the cusp on November 13, 1996, at 1900 UT, by using data of the SuperDARN radar, and of the IMAGE, Greenland, MACCS and CANOPUS magnetometer arrays; and from other magnetometer stations. The event occurs similar to 20 minutes after a transi......We analyze an ionospheric "enhanced convection event" in the cusp on November 13, 1996, at 1900 UT, by using data of the SuperDARN radar, and of the IMAGE, Greenland, MACCS and CANOPUS magnetometer arrays; and from other magnetometer stations. The event occurs similar to 20 minutes after...

  2. The fabrication and performance of YBa[sub 2]Cu[sub 3]O[sub 7-x] SQUID magnetometers

    Energy Technology Data Exchange (ETDEWEB)

    Kingston, J.J.

    1992-07-01

    To enhance the SQUID's field sensitivity, it is coupled to a flux transformer, a closed superconducting circuit consisting of a pickup loop, to which a signal is applied, connected in series to an input coil, which is inductively coupled to the SQUID. To fabricate an optimal flux transformer, one must use more than one superconducting thin-film layer, each of which is patterned into narrow strips or wires. Some wires from different layers cross, yet remain electrically isolated, to form crossovers, while in other places there must be superconducting contact between wires from different layers. Together, the superconducting wire, superconducting-superconducting contact and the superconducting crossover constitute a superconducting interconnect or multilayer wiring technology. We discuss the development of an interconnect technology involving the high transition temperature ([Tc]) superconductor YBa[sub 2]Cu[sub 3]O[sub 7-x] (YBCO). Because of the need for epitaxial growth there are limits on materials for the insulating layer separating the YBCO films in multilayer structures, and on deposition and patterning techniques. We discuss the use of pulsed laser deposition in conjunction with patterning by shadow masks and later by photolithography to produce interconnects, multiturn input coils, and flux transformers. We also discuss the performance of SQUID magnetometers, in which a flux transformer fabricated on one substrate is coupled to a SQUID fabricated on another. The first magnetometers were hybrids -- high [Tc] transformers coupled to low [Tc] SQUIDS, while later ones had both high [Tc] transformers and SQUIDs and could operate immersed in liquid nitrogen. We report on a magnetometer with a magnetic field sensitivity at lHz of about 2pTHz[minus][sup 1/2] at 77K, that was successfully used to perform magnetocardiograms on human subjects.

  3. IMF By effects on ground magnetometer response to increased solar wind dynamic pressure derived from global MHD simulations

    Science.gov (United States)

    Ozturk, Dogacan Su; Zou, Shasha; Slavin, James A.

    2017-05-01

    During sudden solar wind dynamic pressure enhancements, the magnetosphere undergoes rapid compression resulting in a reconfiguration of the global current systems, most notably the field-aligned currents (FACs). Ground-based magnetometers are traditionally used to study such compression events. However, factors affecting the polarity and magnitude of the ground-based magnetic perturbations are still not well understood. In particular, interplanetary magnetic field (IMF) By is known to create significant asymmetries in the FAC patterns. We use the University of Michigan Block Adaptive Tree Roe Upwind Scheme (BATS'R'US) magnetohydrodynamic code to investigate the effects of IMF By on the global variations of ground magnetic perturbations during solar wind dynamic pressure enhancements. Using virtual magnetometers in three idealized simulations with varying IMF By, we find asymmetries in the peak amplitude and magnetic local time of the ground magnetic perturbations during the preliminary impulse (PI) and the main impulse (MI) phases. These asymmetries are especially evident at high-latitude ground magnetometer responses where the peak amplitudes differ by 50 nT at different locations. We show that the FACs related with the PI are due to magnetopause deformation, and the FACs related with the MI are generated by vortical flows within the magnetosphere, consistent with other simulation results. The perturbation FACs due to pressure enhancements and their magnetospheric sources do not differ much under different IMF By polarities. However, the conductance profile affected by the superposition of the preexisting FACs and the perturbation FACs including their closure currents is responsible for the magnitude and location asymmetries in the ground magnetic perturbations.

  4. Multi-core Microprocessors

    Indian Academy of Sciences (India)

    programming and computer fundamentals. His current research interests are parallel computing and history of computing. Multi-core microprocessor is an interconnected set of inde- pendent processors called cores integrated on a single sili- con chip. These processing cores communicate and cooperate with one another ...

  5. Core Competence and Education.

    Science.gov (United States)

    Holmes, Gary; Hooper, Nick

    2000-01-01

    Outlines the concept of core competence and applies it to postcompulsory education in the United Kingdom. Adopts an educational perspective that suggests accreditation as the core competence of universities. This economic approach suggests that the market trend toward lifetime learning might best be met by institutions developing a core competence…

  6. Measurement of intravenously administered γ-Fe2O3 particle amount in mice tissues using vibrating sample magnetometer.

    Science.gov (United States)

    Kishimoto, Mikio; Miyamoto, Ryoichi; Oda, Tatsuya; Ohara, Yusuke; Yanagihara, Hideto; Ohkohchi, Nobuhiro; Kita, Eiji

    2014-12-01

    Dispersions of platelet γ-Fe2O3 particles 30-50nm in size were intravenously administered to mice and the amount of particles accumulated in each tissue was obtained by magnetization measurement using a vibrating sample magnetometer. Background noise was greatly reduced by measuring dried tissues under a magnetic field of 500 Oe so that the effect of diamagnetism was slight. Remarkable particle accumulation was observed in the liver and spleen. Considerable particle accumulation was observed in the lung when a large quantity of γ-Fe2 O3 particles was administered. There was no significant particle accumulation in the kidney and heart.

  7. Miniature Free-Flying Magnetometer Utilizing System-On-A-Chip Technology

    Science.gov (United States)

    Blaes, B. R.; Eyre, F. B.

    2001-01-01

    Four Free-Flying Magnetometers (FFMs), developed at the Jet Propulsion Laboratory (JPL) for the Enstrophy mission, were successfully deployed from the payload of a sounding rocket launched from Poker Flats, Alaska on February 11, 1999. The FFMs functioned successfully by synchronously measuring the vector magnetic field at 4 points separate from the payload and at relative distances up to 3 km, and communicated their data, in bursts, to the ground. This is the first time synchronized in-situ multipoint measurements of the Earth's magnetic field utilizing miniature spin-stabilized "sensorcraft" have been performed. The data they provided have enabled, for the first time, the direct measure of field-aligned current density and are enabling new science by determining the fine-scale structure of the currents in the Earth's ionosphere involved in the production of aurora. These proof-of-concept "hockey puck" (80 mm diameter, 38 mm height, 250 gram mass) FFMs were built using off-the-shelf commercial, industrial, and military grade surface-mount electronic components. Radiation-hard electronics was not required for the Enstrophy mission's short sub-orbital flight. The successful design, implementation, and flight demonstration of this 1st generation FFM design has provided a solid base for further development of a 2nd generation FFM design for planetary science applications. A reliable ultra-miniature radiation-hard 2nd-generation FFM utilizing System-On-A-Chip (SOAC) technologies is proposed. This design would be targeted for long-term planetary missions to investigate magnetospheric field configurations in regions having small-scale structure and to separate spatial and temporal variations. A fleet of short-lived (expendable) FFMs would be deployed into a targeted region to gather multiprobe vector magnetic field data. The FFMs would be ejected from a parent spacecraft at a speed of a few m/sec and would cover spatial volumes of order tens of kilometers for times of

  8. Magnetoencephalography with a Cs-based high-sensitivity compact atomic magnetometer

    Science.gov (United States)

    Sheng, Jingwei; Wan, Shuangai; Sun, Yifan; Dou, Rongshe; Guo, Yuhao; Wei, Kequan; He, Kaiyan; Qin, Jie; Gao, Jia-Hong

    2017-09-01

    In recent years, substantial progress has been made in developing a new generation of magnetoencephalography (MEG) with a spin-exchange relaxation free (SERF)-based atomic magnetometer (AM). An AM employs alkali atoms to detect weak magnetic fields. A compact AM array with high sensitivity is crucial to the design; however, most proposed compact AMs are potassium (K)- or rubidium (Rb)-based with single beam configurations. In the present study, a pump-probe two beam configuration with a Cesium (Cs)-based AM (Cs-AM) is introduced to detect human neuronal magnetic fields. The length of the vapor cell is 4 mm, which can fully satisfy the need of designing a compact sensor array. Compared with state-of-the-art compact AMs, our new Cs-AM has two advantages. First, it can be operated in a SERF regime, requiring much lower heating temperature, which benefits the sensor with a closer distance to scalp due to ease of thermal insulation and less electric heating noise interference. Second, the two-beam configuration in the design can achieve higher sensitivity. It is free of magnetic modulation, which is necessary in one-beam AMs; however, such modulation may cause other interference in multi-channel circumstances. In the frequency band between 10 Hz and 30 Hz, the noise level of the proposed Cs-AM is approximately 10 f T/Hz1/2, which is comparable with state-of-the-art K- or Rb-based compact AMs. The performance of the Cs-AM was verified by measuring human auditory evoked fields (AEFs) in reference to commercial superconducting quantum interference device (SQUID) channels. By using a Cs-AM, we observed a clear peak in AEFs around 100 ms (M100) with a much larger amplitude compared with that of a SQUID, and the temporal profiles of the two devices were in good agreement. The results indicate the possibility of using the compact Cs-AM for MEG recordings, and the current Cs-AM has the potential to be designed for multi-sensor arrays and gradiometers for future neuroscience

  9. Rotation reversal bifurcation and energy confinement saturation in tokamak Ohmic L-mode plasmas.

    Science.gov (United States)

    Rice, J E; Cziegler, I; Diamond, P H; Duval, B P; Podpaly, Y A; Reinke, M L; Ennever, P C; Greenwald, M J; Hughes, J W; Ma, Y; Marmar, E S; Porkolab, M; Tsujii, N; Wolfe, S M

    2011-12-23

    Direction reversals of intrinsic toroidal rotation have been observed in diverted Alcator C-Mod Ohmic L-mode plasmas following electron density ramps. For low density discharges, the core rotation is directed cocurrent, and reverses to countercurrent following an increase in the density above a certain threshold. Such reversals occur together with a decrease in density fluctuations with 2 cm(-1)≤k(θ)≤11 cm(-1) and frequencies above 70 kHz. There is a strong correlation between the reversal density and the density at which the Ohmic L-mode energy confinement changes from the linear to the saturated regime.

  10. Postponement of saturation of the Richtmyer-Meshkov instability in a convergent geometry.

    Science.gov (United States)

    Fincke, J R; Lanier, N E; Batha, S H; Hueckstaedt, R M; Magelssen, G R; Rothman, S D; Parker, K W; Horsfield, C J

    2004-09-10

    Strongly shocked cylindrically convergent implosions were conducted on the OMEGA laser. The directly driven targets consist of a low-density foam core and an embedded aluminum shell covered by an epoxy ablator. The outer surface of the aluminum shell has imposed single-mode perturbations with wave numbers k=0.08, 0.25, and 0.7 (rad/microm) and initial amplitudes eta(0)/lambda=0.013, 0.04 and 0.11. The perturbation growth rate is found to scale with k and, in our convergent geometry, no evidence of saturation for eta/lambda as large as 5 is observed.

  11. Core stability exercise principles.

    Science.gov (United States)

    Akuthota, Venu; Ferreiro, Andrea; Moore, Tamara; Fredericson, Michael

    2008-02-01

    Core stability is essential for proper load balance within the spine, pelvis, and kinetic chain. The so-called core is the group of trunk muscles that surround the spine and abdominal viscera. Abdominal, gluteal, hip girdle, paraspinal, and other muscles work in concert to provide spinal stability. Core stability and its motor control have been shown to be imperative for initiation of functional limb movements, as needed in athletics. Sports medicine practitioners use core strengthening techniques to improve performance and prevent injury. Core strengthening, often called lumbar stabilization, also has been used as a therapeutic exercise treatment regimen for low back pain conditions. This article summarizes the anatomy of the core, the progression of core strengthening, the available evidence for its theoretical construct, and its efficacy in musculoskeletal conditions.

  12. Magnetic properties of monodispersed Ni/NiO core-shell nanoparticles.

    Science.gov (United States)

    Seto, Takafumi; Akinaga, Hiroyuki; Takano, Fumiyoshi; Koga, Kenji; Orii, Takaaki; Hirasawa, Makoto

    2005-07-21

    We have recently developed a method to fabricate monodispersed Ni/NiO core-shell nanoparticles by pulsed laser ablation. In this report, the size-dependent magnetic properties of monodispersed Ni/NiO core-shell nanoparticles were investigated. These nanoparticles were formed in two steps. The first was to fabricate a series of monodispersed Ni nanoparticles of 5 to 20 nm in diameter using a combination of laser ablation and size classification by a low-pressure differential mobility analyzer (DMA). The second step was to oxidize the surfaces of the Ni particles in situ to form core-shell structures. A superconducting quantum interference device (SQUID) magnetometer was used to measure the magnetic properties of nanostructured films prepared by depositing the nanoparticles at room temperature. Ferromagnetism was observed in the magnetic hysteresis loop of the nanostructured films composed of core-shell nanoparticles with core diameters smaller than the superparamagnetic limit, which suggests the spin of Ni core was weakly exchange coupled with antiferromagnetic NiO shell. In contrast, smaller nanoparticles with core diameters of 3.0 nm exhibited superparamagnetism. The drastic change in the hysteresis loops between field-deposited and zero-field-deposited samples was attributable to the strong anisotropy that developed during the magnetic-field-assisted nanostructuring process.

  13. Saturation of Van Allen's belts; Saturation des ceintures de Van Allen

    Energy Technology Data Exchange (ETDEWEB)

    Le Bel, E.; Simonet, F. [CEA Bruyeres-le-Chatel, 91 (France)

    2002-12-01

    The maximum number of electrons that can be trapped in van Allen's belts has been evaluated at CEA-DAM more precisely than that commonly used in the space community. The modelization that we have developed allows to understand the disagreement (factor 50) observed between the measured and predicted electrons flux by US satellites and theory. This saturation level allows sizing-up of the protection on a satellite in case of energetic events. (authors)

  14. Reaching saturation in patterned source vertical organic field effect transistors

    Science.gov (United States)

    Greenman, Michael; Sheleg, Gil; Keum, Chang-min; Zucker, Jonathan; Lussem, Bjorn; Tessler, Nir

    2017-05-01

    Like most of the vertical transistors, the Patterned Source Vertical Organic Field Effect Transistor (PS-VOFET) does not exhibit saturation in the output characteristics. The importance of achieving a good saturation is demonstrated in a vertical organic light emitting transistor; however, this is critical for any application requiring the transistor to act as a current source. Thereafter, a 2D simulation tool was used to explain the physical mechanisms that prevent saturation as well as to suggest ways to overcome them. We found that by isolating the source facet from the drain-source electric field, the PS-VOFET architecture exhibits saturation. The process used for fabricating such saturation-enhancing structure is then described. The new device demonstrated close to an ideal saturation with only 1% change in the drain-source current over a 10 V change in the drain-source voltage.

  15. Brain oxygen saturation assessment in neonates using T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy.

    Science.gov (United States)

    Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra Ma; Hendrikse, Jeroen; Groenendaal, Floris; van Bel, Frank; Benders, Manon Jnl; Petersen, Esben T

    2017-03-01

    Although near-infrared spectroscopy is increasingly being used to monitor cerebral oxygenation in neonates, it has a limited penetration depth. The T2-prepared Blood Imaging of Oxygen Saturation (T2-BIOS) magnetic resonance sequence provides an oxygen saturation estimate on a voxel-by-voxel basis, without needing a respiratory calibration experiment. In 15 neonates, oxygen saturation measured by T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy were compared. In addition, these measures were compared to cerebral blood flow and venous oxygen saturation in the sagittal sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy ( R2 = 0.64, p infrared spectroscopy oxygen saturation, and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus ( R2 = 0.71, 0.50, 0.65; p infrared spectroscopy and T2-prepared blood imaging of oxygen saturation, confirming the validity of using of these techniques for determining cerebral oxygenation.

  16. HYDRATE CORE DRILLING TESTS

    Energy Technology Data Exchange (ETDEWEB)

    John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

    2002-11-01

    The ''Methane Hydrate Production from Alaskan Permafrost'' project is a three-year endeavor being conducted by Maurer Technology Inc. (MTI), Noble, and Anadarko Petroleum, in partnership with the U.S. DOE National Energy Technology Laboratory (NETL). The project's goal is to build on previous and ongoing R&D in the area of onshore hydrate deposition. The project team plans to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope includes drilling and coring one well on Anadarko leases in FY 2003 during the winter drilling season. A specially built on-site core analysis laboratory will be used to determine some of the physical characteristics of the hydrates and surrounding rock. Prior to going to the field, the project team designed and conducted a controlled series of coring tests for simulating coring of hydrate formations. A variety of equipment and procedures were tested and modified to develop a practical solution for this special application. This Topical Report summarizes these coring tests. A special facility was designed and installed at MTI's Drilling Research Center (DRC) in Houston and used to conduct coring tests. Equipment and procedures were tested by cutting cores from frozen mixtures of sand and water supported by casing and designed to simulate hydrate formations. Tests were conducted with chilled drilling fluids. Tests showed that frozen core can be washed out and reduced in size by the action of the drilling fluid. Washing of the core by the drilling fluid caused a reduction in core diameter, making core recovery very difficult (if not impossible). One successful solution was to drill the last 6 inches of core dry (without fluid circulation). These tests demonstrated that it will be difficult to capture core when drilling in permafrost or hydrates without implementing certain safeguards. Among the coring tests was a simulated hydrate

  17. In-situ gas hydrate hydrate saturation estimated from various well logs at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

    Science.gov (United States)

    Lee, M.W.; Collett, T.S.

    2011-01-01

    In 2006, the U.S. Geological Survey (USGS) completed detailed analysis and interpretation of available 2-D and 3-D seismic data and proposed a viable method for identifying sub-permafrost gas hydrate prospects within the gas hydrate stability zone in the Milne Point area of northern Alaska. To validate the predictions of the USGS and to acquire critical reservoir data needed to develop a long-term production testing program, a well was drilled at the Mount Elbert prospect in February, 2007. Numerous well log data and cores were acquired to estimate in-situ gas hydrate saturations and reservoir properties.Gas hydrate saturations were estimated from various well logs such as nuclear magnetic resonance (NMR), P- and S-wave velocity, and electrical resistivity logs along with pore-water salinity. Gas hydrate saturations from the NMR log agree well with those estimated from P- and S-wave velocity data. Because of the low salinity of the connate water and the low formation temperature, the resistivity of connate water is comparable to that of shale. Therefore, the effect of clay should be accounted for to accurately estimate gas hydrate saturations from the resistivity data. Two highly gas hydrate-saturated intervals are identified - an upper ???43 ft zone with an average gas hydrate saturation of 54% and a lower ???53 ft zone with an average gas hydrate saturation of 50%; both zones reach a maximum of about 75% saturation. ?? 2009.

  18. Saturated fat -a never ending story?

    Science.gov (United States)

    Svendsen, Karianne; Arnesen, Erik; Retterstøl, Kjetil

    2017-01-01

    Science has no clear message regarding health effects of saturated fats, it seems. Different RCTs, prospective cohort studies and meta-analysis have led to contrasting conclusions. The aim of the present commentary is to discuss some possible reasons for an apparently never-ending fat controversy. They are of a purely scientific nature, which is important to recognize, but unfortunately hard to overcome. First is the placebo problem. In pharmaceutical science, evidence-based medicine is often synonymous with data on verified medical events from long-lasting double-blind randomized placebo controlled trials. In nutritional science the lack of double-blind design and lack of placebo food generate less conclusive data than those achieved in pharmaceutical science. Some scientists may apply the same type of scientific criteria used to evaluate the effects of drugs for foods. This leaves an impression of insufficient data since in this respect the fundamental criteria for evidence based medicine are not present. The next scientific problem is the energy balance equation. In contrast to pharmaceuticals, nutrients contain energy. An increased intake of one nutrient will lead to a decreased intake of another. The effect of change in only one nutrient is then difficult to isolate. Lastly, in nutritional science, generalizability is difficult compared to pharmaceutical science. Food culture interferes with lifestyle and food habits change over time. In conclusion, all available knowledge, from molecular experiments to population studies, must be taken in to account, to convert scientific data into dietary recommendations.

  19. Sensorial saturation and neonatal pain: a review.

    Science.gov (United States)

    Locatelli, Chiara; Bellieni, Carlo Valerio

    2017-08-23

    Sensorial saturation (SS) is an analgesic approach to babies' pain that includes three types of stimulations: oral sugar, massage and caregivers' voice. The aim of this review is to assess its efficacy. We performed an analysis of scientific literature from 2001 to 2017, retrieving those clinical trials where SS had been compared with other analgesic treatments during procedural pain in babies. We retrieved 14 studies. Pain sources were heel-prick in nine, eye examination and intramuscular shots in two each, and endotracheal aspiration in one. SS was the most effective treatment in all cases, except in endotracheal suctioning. No drawbacks were reported in any study using SS. SS is a safe and effective approach to neonatal pain due to heel-prick, more effective than oral sucrose or glucose in both term and preterm babies; it seems also effective in other types of acute procedural pain like eye examination or intramuscular injections, but more studies are needed to confirm these preliminary data. More studies are also needed to test SS efficacy for other procedures, and for older infants.

  20. SATURATED ZONE FLOW AND TRANSPORT MODEL ABSTRACTION

    Energy Technology Data Exchange (ETDEWEB)

    B.W. ARNOLD

    2004-10-27

    The purpose of the saturated zone (SZ) flow and transport model abstraction task is to provide radionuclide-transport simulation results for use in the total system performance assessment (TSPA) for license application (LA) calculations. This task includes assessment of uncertainty in parameters that pertain to both groundwater flow and radionuclide transport in the models used for this purpose. This model report documents the following: (1) The SZ transport abstraction model, which consists of a set of radionuclide breakthrough curves at the accessible environment for use in the TSPA-LA simulations of radionuclide releases into the biosphere. These radionuclide breakthrough curves contain information on radionuclide-transport times through the SZ. (2) The SZ one-dimensional (I-D) transport model, which is incorporated in the TSPA-LA model to simulate the transport, decay, and ingrowth of radionuclide decay chains in the SZ. (3) The analysis of uncertainty in groundwater-flow and radionuclide-transport input parameters for the SZ transport abstraction model and the SZ 1-D transport model. (4) The analysis of the background concentration of alpha-emitting species in the groundwater of the SZ.

  1. Highly sensitive YBa2Cu3O7 dc SQUID magnetometer with thin-film flux transformer

    Science.gov (United States)

    Grundler, D.; David, B.; Eckart, R.; Dössel, O.

    1993-11-01

    We have designed and fabricated a thin-film flux transformer by a YBa2Cu3O7/SrTiO3 (YBCO/STO) multilayer process. The flux transformer consists of a 20-turn input coil of 10 μm linewidth and a single-turn pickup loop surrounding an area of 7.5 by 7.5 mm2. All device levels are patterned by standard photolithography and Ar-ion-beam etching. The flux transformer has been combined in flip-chip configuration with the square washer of a low-noise YBCO dc SQUID. The dc SQUID magnetometer exhibits a magnetic field sensitivity of 1.4 nT/Φ0. The intrinsic white flux noise level of 70μΦ0/√Hz at 77 K is mainly dominated by the SQUID corresponding to a magnetic field resolution of the magnetometer of 100 fT/√Hz for frequencies above 40 Hz. At 1 Hz we measured 200 fT/√Hz. Biomagnetic measurements were performed in a magnetically shielded chamber.

  2. Quantifying the spatio-temporal correlation during a substorm using dynamical networks formed from the SuperMAG database of ground based magnetometer stations.

    Science.gov (United States)

    Dods, J.; Chapman, S. C.; Gjerloev, J. W.; Barnes, R. J.

    2014-12-01

    The overall morphology and dynamics of magnetospheric substorms is well established in terms of observed qualitative auroral features and signatures seen in ground based magnetometers. The detailed evolution of a given substorm is captured by typically ~100 ground based magnetometer observations and this work seeks to synthesise all these observations in a quantitative manner. We present the first analysis of the full available set of ground based magnetometer observations of substorms using dynamical networks. SuperMAG offers a database containing ground station magnetometer data at a cadence of 1min from 100s stations situated across the globe. We use this data to form dynamic networks which capture spatial dynamics on timescales from the fast reconfiguration seen in the aurora, to that of the substorm cycle. Windowed linear cross-correlation between pairs of magnetometer time series along with a threshold is used to determine which stations are correlated and hence connected in the network. Variations in ground conductivity and differences in the response functions of magnetometers at individual stations are overcome by normalizing to long term averages of the cross-correlation. These results are tested against surrogate data in which phases have been randomised. The network is then a collection of connected points (ground stations); the structure of the network and its variation as a function of time quantify the detailed dynamical processes of the substorm. The network properties can be captured quantitatively in time dependent dimensionless network parameters and we will discuss their behaviour for examples of 'typical' substorms and storms. The network parameters provide a detailed benchmark to compare data with models of substorm dynamics, and can provide new insights on the similarities and differences between substorms and how they correlate with external driving and the internal state of the magnetosphere.

  3. The 3 Hours-hydrothermal Synthesis of High Surface Area Super Paramagnetic Fe3o4 Core-shell Nano Particles

    OpenAIRE

    Octiana Sari, Esty; Fadli, Ahmad; Amri, Amun

    2017-01-01

    THE 3 HOURS-HYDROTHERMAL SYNTHESIS OF HIGH SURFACE AREA SUPER PARAMAGNETIC Fe3O4 CORE-SHELL NANO PARTICLES. The monodisperse core-shell Fe3O4 nanoparticles have been successfully synthesized by short times (3 hours) hydrothermal method at 220-oC from FeCl3, citrate, urea and PEG. The as-synthesized samples have been characterized using X-RayDiffraction (XRD), Transmission Electron Microscope (TEM), Bruneur-Emmet-Teller (BET) surface area analyzer, and Vibrating Sample Magnetometer (VSM). The ...

  4. Stimulation of sulfate-reducing activity at salt-saturation in the salterns of Ribandar, Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Kerkar, S.; LokaBharathi, P.A.

    straw-mud plugs in the bandhs. Water gets heated up evaporates in the sun, forming frothy layer at saturation. To speed up crystallization, the pan is seeded with crude salt. In the peak salt producing season, salt is harvested and collected daily.... Part1: Unammended sediment from 3 depths incubated for 24 and 48hrs: Triplicate mini cores from the above intact cores (85 and 330 psu) were prepared corresponding to the three depths by removing the luer tips from plastic disposable syringes (2ml...

  5. Amendment of saturation magnetization, blocking temperature and particle size homogeneity in Mn-ferrite nanoparticles using Co-Zn substitution

    Energy Technology Data Exchange (ETDEWEB)

    Eltabey, M.M. [Basic Engineering Science Department, Faculty of Engineering, Menoufiya University (Egypt); Physics Department, Faculty of Science, Jazan University, Jazan (Saudi Arabia); Massoud, A.M., E-mail: Amassouda1@yahoo.com [Physics Department, Faculty of Science, Ain Shams University, Abbassia 11566, Cairo (Egypt); Radu, Cosmin [Lake Shore Cryotronics, Inc., Westerville, OH (United States)

    2017-01-15

    Nanocrystalline particles of compositions (CoZn){sub x}Mn{sub 1−x}Fe{sub 2}O{sub 4} were prepared by the coprecipitation method from stoichiometric aqueous solutions, where x varies from 0 to 0.3 in steps of 0.05. The synthesized powders were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FT-IR). A vibrating sample magnetometer (VSM) was used to measure the hysteresis parameters at 300 and 6 K. Zero field cooling (ZFC) and field cooling (FC) curves were obtained at the temperature range 6–400 K and the blocking temperature values were determined. XRD analysis confirmed the formation of the obtained powder in a single cubic spinel phase and it showed also that the lattice parameter is decreasing with the increase of (Co-Zn) content. FT-IR measurements between 160 and 650 cm{sup −1} also confirmed the intrinsic cation vibrations of the spinel structure. The magnetic measurements showed that the saturation magnetization, coercivity and the values of blocking temperatures were increased with the (Co-Zn) content. TEM micrographs declared the improvement of particle size homogeneity with the increase of (Co-Zn) content without remarkable change in the average particle size. The obtained results were discussed in view of A-B sublattices interaction and superparamagnetic phenomenon. - Highlights: • Nanocrystalline particles of compositions (CoZn){sub x}Mn{sub 1-x}Fe{sub 2}O{sub 4} were prepared by the coprecipitation method. • XRD analysis showed that the lattice parameter is decreased with the increase of (Co,Zn) content. • The saturation magnetization is improved with the (Co,Zn) content. • Particle size homogeneity is enhanced with (Co,Zn) content. • The values of blocking temperatures are enhanced with increasing (Co,Zn) content.

  6. Can Polyphosphate Biochemistry Affect Biological Apatite Saturation?

    Science.gov (United States)

    Omelon, S. J.; Matsuura, N.; Gorelikov, I.; Wynnyckyj, C.; Grynpas, M. D.

    2010-12-01

    Phosphorus (P) is an important and limiting element for life. One strategy for storing ortho phosphates (Pi) is polymerization. Polymerized Pi's (polyphosphates: (PO3-)n: polyPs) serve as a Pi bank, as well as a catiion chelator, energy source, & regulator of responses to stresses in the stationary phase of culture growth and development1. PolyP biochemistry has been investigated in yeasts, bacteria & plants2. Bigeochemical cycling of P includes the condensation of Pi into pyro (P2O7-4), & polyPs, & the release of Pi from these compounds by the hydrolytic degradation of Pi from phosphomonoester bonds. Alkaline phosphatase (ALP) is one of the predominate enzymes for regenerating Pi in aquatic systems3, & it cleaves Pi from polyPs. ALP is also the enzyme associated with apatite biomineralization in vertebrates4. PolyP was proposed to be the ALP substrate in bone mineralization5. Where calcium ions are plentiful in many aquatic environments, there is no requirement for aquatic life to generate Ca-stores. However, terrestrial vertebrates benefit from a bioavailable Ca-store such as apatite. The Pi storage strategy of polymerizing PO4-3 into polyPs dovetails well with Ca-banking, as polyPs sequester Ca, forming a neutral calcium polyphosphate (Ca-polyP: (Ca(PO3)2)n) complex. This neutral complex represents a high total [Ca+2] & [PO4-3], without the threat of inadvertent apatite precipitation, as the free [Ca+2] & [PO4-3], and therefore apatite saturation, are zero. Recent identification of polyP in regions of bone resorption & calcifying cartilage5 suggests that vertebrates may use polyP chemistry to bank Ca+2 and PO4-3. In vitro experiments with nanoparticulate Ca-polyP & ALP were undertaken to determine if carbonated apatite could precipitate from 1M Ca-polyP in Pi-free “physiological fluid” (0.1 M NaCl, 2 mM Ca+2, 0.8 mM Mg+2, pH ~8.0 ±0.5, 37 °C), as this is estimated to generate the [Ca+2] & [PO4-3] required to form the apatite content of bone tissue

  7. Extended and saturation prostatic biopsy in the diagnosis and characterisation of prostate cancer: a critical analysis of the literature.

    Science.gov (United States)

    Scattoni, Vincenzo; Zlotta, Alexandre; Montironi, Rodolfo; Schulman, Claude; Rigatti, Patrizio; Montorsi, Francesco

    2007-11-01

    To review and critically analyse all the recent literature on the detection and characterisation of prostate cancer by means of extended and saturation protocols. A systematic review of the literature was performed by searching MedLine from January 1995 to April 2007. Electronic searches were limited to the English language, and the key words "prostate cancer," "diagnosis," "transrectal ultrasound (TRUS)," "prostate biopsy," and "prognosis" were used. The prostate biopsy technique has changed significantly since the original Hodge sextant biopsy protocol. Several types of local anaesthesia are now available, but periprostatic nerve block (PPNB) has proved to be the most effective method to reduce pain during TRUS biopsy. It remains controversial whether PPNB should be associated with other medications. The optimal extended protocol (sextant template with at least four additional cores) should include six standard sextant biopsies, with additional biopsies (up to 12 cores) taken more laterally (anterior horn) to the base and medially to the apex. Repeat biopsies should be based on saturation biopsies (number of cores >/= 20) and should include the transition zone, especially in a patient with an initial negative biopsy. As a means of increasing accuracy of prostatic biopsy and reducing unnecessary prostate biopsy, colour and power Doppler imaging, with or without contrast enhancement, and elastography now can be successfully adopted, but their routine use is still controversial. Extended and saturation biopsy schemes should be performed at first and repeat biopsy, respectively. The widespread use of local anaesthesia makes the procedures more comfortable.

  8. Sediment Core Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides instrumentation and expertise for physical and geoacoustic characterization of marine sediments.DESCRIPTION: The multisensor core logger measures...

  9. Adaptive core simulation

    Science.gov (United States)

    Abdel-Khalik, Hany Samy

    The work presented in this thesis is a continuation of a master's thesis research project conducted by the author to gain insight into the applicability of inverse methods to developing adaptive simulation capabilities for core physics problems. Use of adaptive simulation is intended to improve the fidelity and robustness of important core attributes predictions such as core power distribution, thermal margins and core reactivity. Adaptive simulation utilizes a selected set of past and current reactor measurements of reactor observables, i.e. in-core instrumentations readings, to adapt the simulation in a meaningful way. A meaningful adaption will result in high fidelity and robust adapted core simulators models. To perform adaption, we propose an inverse theory approach in which the multitudes of input data to core simulators, i.e. reactor physics and thermal-hydraulic data, are to be adjusted to improve agreement with measured observables while keeping core simulators models unadapted. At a first glance, devising such adaption for typical core simulators models would render the approach impractical. This follows, since core simulators are based on very demanding computational models, i.e. based on complex physics models with millions of input data and output observables. This would spawn not only several prohibitive challenges but also numerous disparaging concerns. The challenges include the computational burdens of the sensitivity-type calculations required to construct Jacobian operators for the core simulators models. Also, the computational burdens of the uncertainty-type calculations required to estimate the uncertainty information of core simulators input data presents a demanding challenge. The concerns however are mainly related to the reliability of the adjusted input data. We demonstrate that the power of our proposed approach is mainly driven by taking advantage of this unfavorable situation. Our contribution begins with the realization that to obtain

  10. Residual-oil-saturation-technology test, Bell Creek Field, Montana. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-06-01

    A field test was conducted of the technology available to measure residual oil saturation following waterflood secondary oil recovery processes. The test was conducted in a new well drilled solely for that purpose, located immediately northwest of the Bell Creek Micellar Polymer Pilot. The area where the test was conducted was originally drilled during 1968, produced by primary until late 1970, and was under line drive waterflood secondary recovery until early 1976, when the area was shut in at waterflood depletion. This report presents the results of tests conducted to determine waterflood residual oil saturation in the Muddy Sandstone reservoir. The engineering techniques used to determine the magnitude and distribution of the remaining oil saturation included both pressure and sidewall cores, conventional well logs (Dual Laterolog - Micro Spherically Focused Log, Dual Induction Log - Spherically Focused Log, Borehole Compensated Sonic Log, Formation Compensated Density-Compensated Neutron Log), Carbon-Oxygen Logs, Dielectric Logs, Nuclear Magnetism Log, Thermal Decay Time Logs, and a Partitioning Tracer Test.

  11. Core physics experiment of 100% MOX core: MISTRAL

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, T.; Matsu-ura, H.; Ueji, M. [Nuclear Power Engineering Corp., Tokyo (Japan); Cathalau, S.; Cabrillat, J.C.; Chauvin, J.P.; Finck, P.J.; Fougeras, P.; Flamenbaum, G.

    1997-12-31

    An extensive experimental program, MISTRAL, was undertaken in the EOLE critical facility of CEA in order to measure the main core physics parameters of 100% MOX loaded cores of light water reactors. The experimental program comprises four core configurations with high moderator to fuel ratio, including three homogeneous cores and one PWR type mock-up core. This paper presents the experiment of the first homogeneous core of uranium fuel as a reference core of the MOX cores and a part of the experiment of the second core, a 100% MOX homogeneous core. (author)

  12. Poly(amidehydroxyurethane template magnetite NPs electrosynthesis. II. Core and shell characterization

    Directory of Open Access Journals (Sweden)

    Laura Ursu

    2013-10-01

    Full Text Available Core and layer polymer characterization of magnetite nanoparticles (NPs surface-functionalized with poly(amidehydroxyurethane (PAmHU, obtained by a new electrochemical synthesis route is presented. The core magnetic properties were investigated by Vibrating Sample Magnetometer (VSM, showing that the obtained NPs have superparamagnetic to ferromagnetic behaviour (very low coercivity and remanence. The magnetite–PAmHU NPs morphology and size were studied by Atomic Force Microscopy (AFM and Dynamic Light Scattering (DLS; both methods showed the existence of PAmHU out-flaked layer on NPs. Structural analysis by Infrared spectroscopy (FTIR and Thermogravimetry (TG confirm the out-flaking of magnetic NPs with PAmHU.

  13. Coupling-induced cooperative behaviour in dynamic ferromagnetic cores in the presence of a noise floor

    Energy Technology Data Exchange (ETDEWEB)

    Bulsara, Adi R. [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull Street, San Diego, CA 92152-5001 (United States)]. E-mail: bulsara@spawar.navy.mil; Lindner, John F. [Physics Department, College of Wooster, Wooster, OH 44691 (United States); In, Visarath [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull Street, San Diego, CA 92152-5001 (United States); Kho, Andy [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull Street, San Diego, CA 92152-5001 (United States); Baglio, Salvatore [Dipartimento di Ingegneria Elettrica Elettronica e dei Sistemi, Universita degli Studi di Catania, Viale A. Doria 6, 95125 Catania (Italy); Sacco, Vincenzo [Dipartimento di Ingegneria Elettrica Elettronica e dei Sistemi, Universita degli Studi di Catania, Viale A. Doria 6, 95125 Catania (Italy); Ando, Bruno [Dipartimento di Ingegneria Elettrica Elettronica e dei Sistemi, Universita degli Studi di Catania, Viale A. Doria 6, 95125 Catania (Italy); Longhini, Patrick [Nonlinear Dynamics Group, Department of Mathematics, San Diego State University, San Diego, CA 92182 (United States); Palacios, Antonio [Nonlinear Dynamics Group, Department of Mathematics, San Diego State University, San Diego, CA 92182 (United States); Rappel, Wouter-Jan [Physics Department, University of California at San Diego, La Jolla, CA 929093 (United States)

    2006-04-17

    Recently, we have shown the emergence of oscillations in overdamped undriven nonlinear dynamic systems subject to carefully crafted coupling schemes and operating conditions. Here, we summarize experimental results obtained on a system of N=3 coupled ferromagnetic cores, the underpinning of a 'coupled-core fluxgate magnetometer' (CCFM); the oscillatory behaviour is triggered when the coupling constant exceeds a threshold value (bifurcation point), and the oscillation frequency exhibits a characteristic scaling behaviour with the 'separation' of the coupling constant from its threshold value, as well as with an external target DC magnetic flux signal. The oscillations, which can be induced at frequencies ranging from a few Hz to high-kHz, afford a new detection scheme for weak target magnetic signals. We also present the first (numerical) results on the effects of a (Gaussian, exponentially correlated) noise floor on the spectral properties of the system response.

  14. Lamb-Dicke spectroscopy of atoms in a hollow-core photonic crystal fibre

    Science.gov (United States)

    Okaba, Shoichi; Takano, Tetsushi; Benabid, Fetah; Bradley, Tom; Vincetti, Luca; Maizelis, Zakhar; Yampol'skii, Valery; Nori, Franco; Katori, Hidetoshi

    2014-01-01

    Unlike photons, which are conveniently handled by mirrors and optical fibres without loss of coherence, atoms lose their coherence via atom–atom and atom–wall interactions. This decoherence of atoms deteriorates the performance of atomic clocks and magnetometers, and also hinders their miniaturization. Here we report a novel platform for precision spectroscopy. Ultracold strontium atoms inside a kagome-lattice hollow-core photonic crystal fibre are transversely confined by an optical lattice to prevent atoms from interacting with the fibre wall. By confining at most one atom in each lattice site, to avoid atom–atom interactions and Doppler effect, a 7.8-kHz-wide spectrum is observed for the 1S0−3P1(m=0) transition. Atoms singly trapped in a magic lattice in hollow-core photonic crystal fibres improve the optical depth while preserving atomic coherence time. PMID:24934478

  15. Prioritized Control Allocation for Quadrotors Subject to Saturation

    NARCIS (Netherlands)

    Smeur, E.J.J.; de Wagter, C.; J.-M. Moschetta G. Hattenberger, H. de Plinval

    2017-01-01

    This paper deals with the problem of actuator saturation for INDI (Incremental Nonlinear Dynamic Inversion) controlled flying vehicles. The primary problem that arises from actuator saturation for quadrotors, is that of arbitrary control objective realization. We have integrated the weighted least

  16. Polar spots and stellar spindown: is dynamo saturation needed?

    NARCIS (Netherlands)

    Solanki, S. K.; Motamen, S.; Keppens, R.

    1997-01-01

    Dynamo saturation is often invoked when calculating the rotational evolution of cool stars. At rapid rotation rates a saturated dynamo reduces the angular momentum carried away by the stellar wind. This, in turn, may explain the high rotation rates present in the distribution of rotation periods in

  17. Polar spots and stellar spindown: Is dynamo saturation needed?

    NARCIS (Netherlands)

    Solanki, S. K.; Motamen, S.; Keppens, R.

    1997-01-01

    Dynamo saturation is often invoked when calculating the rotational evolution of cool stars. At rapid rotation rates a saturated dynamo reduces the angular momentum carried away by the stellar wind. This, in turn, may explain the high rotation rates present in the distribution of rotation periods in

  18. Gain characteristics of a saturated fiber optic parametric amplifier

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Lorenzen, Michael Rodas; Noordegraaf, Danny

    2008-01-01

    In this work we discuss saturation performance of a fiber optic parametric amplifier. A simple numerical model is described and applied to specific cases. A system experiment using a saturated amplifier illustrates a 4 dB improvement in required signal to noise ratio for a fixed bit error ratio....

  19. Renal vein oxygen saturation in renal artery stenosis

    DEFF Research Database (Denmark)

    Nielsen, K; Rehling, M; Henriksen, Jens Henrik Sahl

    1992-01-01

    Renal vein oxygen-saturation was measured in 56 patients with arterial hypertension and unilateral stenosis or occlusion of the renal artery. Oxygen-saturation in blood from the ischaemic kidney (84.4%, range 73-93%) was significantly higher than that from the 'normal' contralateral kidney (81...

  20. Comparison of empirical models and laboratory saturated hydraulic ...

    African Journals Online (AJOL)

    Numerous methods for estimating soil saturated hydraulic conductivity exist, which range from direct measurement in the laboratory to models that use only basic soil properties. A study was conducted to compare laboratory saturated hydraulic conductivity (Ksat) measurement and that estimated from empirical models.

  1. Stability and stabilization of linear systems with saturating actuators

    CERN Document Server

    Tarbouriech, Sophie; Gomes da Silva Jr, João Manoel; Queinnec, Isabelle

    2011-01-01

    Gives the reader an in-depth understanding of the phenomena caused by the more-or-less ubiquitous problem of actuator saturation. Proposes methods and algorithms designed to avoid, manage or overcome the effects of actuator saturation. Uses a state-space approach to ensure local and global stability of the systems considered. Compilation of fifteen years' worth of research results.

  2. Excitable solitons in a semiconductor laser with a saturable absorber

    Science.gov (United States)

    Turconi, Margherita; Prati, Franco; Barland, Stéphane; Tissoni, Giovanna

    2015-11-01

    Self-pulsing cavity solitons may exist in a semiconductor laser with an intracavity saturable absorber. They show locally the passive Q -switching behavior that is typical of lasers with saturable absorbers in the plane-wave approximation. Here we show that excitable cavity solitons are also possible in a suitable parameter range and characterize their excitable dynamics and properties.

  3. Saturated hydraulic conductivity values of some forest soils of ...

    African Journals Online (AJOL)

    A simple falling-head method is presented for the laboratory determination of saturated hydraulic conductivity of some forest soils of Ghana. Using the procedure, it was found that saturated hydraulic conductivity was positively and negatively correlated with sand content and clay content, respectively, both at P = 0.05 level.

  4. Significance of saturation index of certain clay minerals in shallow ...

    Indian Academy of Sciences (India)

    In reality, a number of kinetic reasons exist that may ..... of SI with increase of pH. This increase of pH reduces the availability of H+ for ion exchange. Group B: The SI of Gibbsite ranges from near saturation to saturation. This may be due to the .... tion of ions in solution which emphasizes increased contribution of species with ...

  5. Serum albumin--a non-saturable carrier

    DEFF Research Database (Denmark)

    Brodersen, R; Honoré, B; Larsen, F G

    1984-01-01

    The shape of binding isotherms for sixteen ligands to human serum albumin showed no signs of approaching saturation at high ligand concentrations. It is suggested that ligand binding to serum albumin is essentially different from saturable binding of substrates to enzymes, of oxygen to haemoglobi...

  6. Retinal oxygen saturation in patients with systemic hypoxemia

    DEFF Research Database (Denmark)

    Traustason, Sindri; Jensen, Annette Schophuus; Arvidsson, Henrik Sven

    2011-01-01

    To assess spectrophotometric oximetry across a broad range of arterial saturation levels and to study the effect of chronic systemic hypoxemia on retinal oxygen extraction.......To assess spectrophotometric oximetry across a broad range of arterial saturation levels and to study the effect of chronic systemic hypoxemia on retinal oxygen extraction....

  7. Estimation of Saturation Flow Rates at Signalized Intersections

    Directory of Open Access Journals (Sweden)

    Chang-qiao Shao

    2012-01-01

    Full Text Available The saturation flow rate is a fundamental parameter to measure the intersection capacity and time the traffic signals. However, it is revealed that traditional methods which are mainly developed using the average value of observed queue discharge headways to estimate the saturation headway might lead to underestimate saturation flow rate. The goal of this paper is to study the stochastic nature of queue discharge headways and to develop a more accurate estimate method for saturation headway and saturation flow rate. Based on the surveyed data, the characteristics of queue discharge headways and the estimation method of saturated flow rate are studied. It is found that the average value of queue discharge headways is greater than the median value and that the skewness of the headways is positive. Normal distribution tests were conducted before and after a log transformation of the headways. The goodness-of-fit test showed that for some surveyed sites, the queue discharge headways can be fitted by the normal distribution and for other surveyed sites, the headways can be fitted by lognormal distribution. According to the queue discharge headway characteristics, the median value of queue discharge headways is suggested to estimate the saturation headway and a new method of estimation saturation flow rates is developed.

  8. Transport of Sr 2+ and SrEDTA 2- in partially-saturated and heterogeneous sediments

    Science.gov (United States)

    Pace, M. N.; Mayes, M. A.; Jardine, P. M.; McKay, L. D.; Yin, X. L.; Mehlhorn, T. L.; Liu, Q.; Gürleyük, H.

    2007-05-01

    Strontium-90 has migrated deep into the unsaturated subsurface beneath leaking storage tanks in the Waste Management Areas (WMA) at the U.S. Department of Energy's (DOE) Hanford Reservation. Faster than expected transport of contaminants in the vadose zone is typically attributed to either physical hydrologic processes such as development of preferential flow pathways, or to geochemical processes such as the formation of stable, anionic complexes with organic chelates, e.g., ethylenediaminetetraacetic acid (EDTA). The goal of this paper is to determine whether hydrological processes in the Hanford sediments can influence the geochemistry of the system and hence control transport of Sr 2+ and SrEDTA 2-. The study used batch isotherms, saturated packed column experiments, and an unsaturated transport experiment in an undisturbed core. Isotherms and repacked column experiments suggested that the SrEDTA 2- complex was unstable in the presence of Hanford sediments, resulting in dissociation and transport of Sr 2+ as a divalent cation. A decrease in sorption with increasing solid:solution ratio for Sr 2+ and SrEDTA 2- suggested mineral dissolution resulted in competition for sorption sites and the formation of stable aqueous complexes. This was confirmed by detection of MgEDTA 2-, MnEDTA 2-, PbEDTA 2-, and unidentified Sr and Ca complexes. Displacement of Sr 2+ through a partially-saturated undisturbed core resulted in less retardation and more irreversible sorption than was observed in the saturated repacked columns, and model results suggested a significant reservoir (49%) of immobile water was present during transport through the heterogeneous layered sediments. The undisturbed core was subsequently disassembled along distinct bedding planes and subjected to sequential extractions. Strontium was unequally distributed between carbonates (49%), ion exchange sites (37%), and the oxide (14%) fraction. An inverse relationship between mass wetness and Sr suggested that

  9. Can Psychiatric Rehabilitation Be Core to CORE?

    Science.gov (United States)

    Olney, Marjorie F.; Gill, Kenneth J.

    2016-01-01

    Purpose: In this article, we seek to determine whether psychiatric rehabilitation principles and practices have been more fully incorporated into the Council on Rehabilitation Education (CORE) standards, the extent to which they are covered in four rehabilitation counseling "foundations" textbooks, and how they are reflected in the…

  10. Development of multicore hybrid particles for drug delivery through the precipitation of CO2 saturated emulsions.

    Science.gov (United States)

    Gonçalves, V S S; Rodríguez-Rojo, S; Matias, A A; Nunes, A V M; Nogueira, I D; Nunes, D; Fortunato, E; de Matos, A P Alves; Cocero, M J; Duarte, C M M

    2015-01-15

    Hybrid lipid-polymer particles are gaining increasing interest to be applied as drug delivery systems due to their greater stability in biological fluids and enhanced cellular uptake of drugs. However, a major drawback is the fact that these particles are usually produced through techniques that use organic solvents. This work studies the possibility of producing for the first time hybrid particles composed by lipid multicores enveloped in a polymeric layer through Particles from Gas Saturated Solutions (PGSS(®)), without using organic solvents. An oil-in-water emulsion, composed by Gelucire 43/01™ (GEL) as the discontinuous phase and by an aqueous polyethylene glycol 4000 (PEG) solution as the continuous phase, was successfully precipitated by PGSS(®). Operating conditions that ensured the stability of the CO2 saturated emulsion were previously evaluated. The resulting PEG-GEL particles present a spherical-like morphology constituted by several lipid cores encapsulated into a polymeric shell. The applicability of these structured particles to be used as drug delivery system (DDS) was studied by using ketoprofen, a nonsteroidal anti-inflammatory drug (NSAID), as model drug. The particles provided an initial burst release of the drug due to the progressive dissolution of the external layer of PEG, followed by a controlled release of the NSAID from the GEL cores. Copyright © 2014. Published by Elsevier B.V.

  11. Electrical Resistivity as an Indicator of Saturation in Fractured Geothermal Reservoir Rocks: Experimental Data and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Detwiler, R L; Roberts, J J

    2003-06-23

    The electrical resistivity of rock cores under conditions representative of geothermal reservoirs is strongly influenced by the state and phase (liquid/vapor) of the pore fluid. In fractured samples, phase change (vaporization/condensation) can result in resistivity changes that are more than an order of magnitude greater than those measured in intact samples. These results suggest that electrical resistivity monitoring of geothermal reservoirs may provide a useful tool for remotely detecting the movement of water and steam within fractures, the development and evolution of fracture systems and the formation of steam caps. We measured the electrical resistivity of cores of welded tuff containing fractures of various geometries to investigate the resistivity contrast caused by active boiling and to determine the effects of variable fracture dimensions and surface area on water extraction from the matrix. We then used the Nonisothermal Unsaturated Flow and Transport model (NUFT) (Nitao, 1998) to simulate the propagation of boiling fronts through the samples. The simulated saturation profiles combined with previously reported measurements of resistivity-saturation curves allow us to estimate the evolution of the sample resistivity as the boiling front propagates into the rock matrix. These simulations provide qualitative agreement with experimental measurements suggesting that our modeling approach may be used to estimate resistivity changes induced by boiling in more complex systems.

  12. Interference Cancellation for Hollow-Core Fiber Reference Cells

    DEFF Research Database (Denmark)

    Seppä, Jeremias; Merimaa, Mikko; Merimaa, Mikko

    2015-01-01

    Doppler-free saturated absorption spectroscopy of gases in hollow-core fiber (HCF)-based cells can be used for realizing new compact, robust, and portable frequency standards. In this paper, methods for cancelling interferences resulting from the optical connections between standard fiber and HCF...... and other factors such as varying coupling to HCF modes are investigated. Laser power modulation with simultaneous detection of ac and dc signal is used to separate saturated absorption from interferences. In addition, a technique of two piezoelectric stack actuators stretching the fiber at different...... locations is described. The presented experimental results demonstrate that 99% interference attenuation is readily attainable with the techniques. Frequency comb-referenced measurement of saturated acetylene absorption features near 1.54 μm, with fiber length and power modulation, is presented...

  13. Magnetization distribution of hydrothermal deposits from three component magnetometer survey using ROV in the Lau Basin, the southwestern Pacific

    Science.gov (United States)

    Kim, C.; Choi, S.; Park, C.

    2013-12-01

    Deep sea three component magnetic surveys, using ROV (Remotely Operated Vehicle), were conducted at Apr., 2011 and Jan., 2012 in TA25 and TA26 seamounts, the Lau Basin, the southwestern Pacific. At 2011, the survey area was only the western slope of the caldera of TA25 using IBRV(Ice Breaker Research Vessel) ARAON of KIOST (Korea Institute of Ocean Science & Technology) and ROV of Oceaneering Co. And, at Jan. 2012, the magnetic survey was conducted in the western (site A) and eastern (site B) slopes of the caldera of TA25 and the summit area of TA26 using German R/V SONNE and ROV of ROPOS Co. The 2011 and 2012 three component magnetic survey lines were the 13 N-S lines and the 29 N-S lines (TA25-East : 12 lines, TA25-West : 11 lines, TA26 : 6 lines) with about 100 m spacing, respectively. Also, we conducted the 8 figure circle rotation survey of ROV for magnetic calibration at 2011 and 2012. For the magnetic survey, the magnetometer sensor was attached with the line frame of ROV and the data logger and motion sensor in ROV. The three component magnetometer measure the X (North), Y (East) and Z (Vertical) vector components of a magnetic field. A motion sensor (Octans) provided us the data of pitch, roll, yaw for the correction of the magnetic data to the motion of ROV. In the survey, ROV followed the tracks of the plan at 50 m above seafloor. The data of the magnetometer and motion sensors and the USBL(Ultra Short Base Line) data of the position of ROV were recorded on a notebook through the optical cable of ROV. Hydrothermal fluids over Curie temperature can quickly alter or replace the iron-rich magnetic minerals, reducing the magnetic remanence of the crustal rocks, in some cases to near 0 A/m magnetization. Low magnetization zones occur in the south-western and northern parts of TA25 site A and the south-south-western, north-western and central parts of TA25 site B. TA26 has low magnetization zones in the central part. The low magnetization zones of the survey

  14. The distribution of saturated clusters in wetted granular materials

    Science.gov (United States)

    Li, Shuoqi; Hanaor, Dorian; Gan, Yixiang

    2017-06-01

    The hydro-mechanical behaviour of partially saturated granular materials is greatly influenced by the spatial and temporal distribution of liquid within the media. The aim of this paper is to characterise the distribution of saturated clusters in granular materials using an optical imaging method under different water drainage conditions. A saturated cluster is formed when a liquid phase fully occupies the pore space between solid grains in a localized region. The samples considered here were prepared by vibrating mono-sized glass beads to form closely packed assemblies in a rectangular container. A range of drainage conditions were applied to the specimen by tilting the container and employing different flow rates, and the liquid pressure was recorded at different positions in the experimental cell. The formation of saturated clusters during the liquid withdrawal processes is governed by three competing mechanisms arising from viscous, capillary, and gravitational forces. When the flow rate is sufficiently large and the gravity component is sufficiently small, the viscous force tends to destabilize the liquid front leading to the formation of narrow fingers of saturated material. As the water channels along these liquid fingers break, saturated clusters are formed inside the specimen. Subsequently, a spatial and temporal distribution of saturated clusters can be observed. We investigated the resulting saturated cluster distribution as a function of flow rate and gravity to achieve a fundamental understanding of the formation and evolution of such clusters in partially saturated granular materials. This study serves as a bridge between pore-scale behavior and the overall hydro-mechanical characteristics in partially saturated soils.

  15. Saturated phosphatidic acids mediate saturated fatty acid–induced vascular calcification and lipotoxicity

    Science.gov (United States)

    Masuda, Masashi; Miyazaki-Anzai, Shinobu; Keenan, Audrey L.; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; Ntambi, James M.; Kuro-o, Makoto; Miyazaki, Makoto

    2015-01-01

    Recent evidence indicates that saturated fatty acid–induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic events in the development of vascular calcification. We evaluated whether SMC-specific inhibition of SCD and the resulting SFA accumulation plays a causative role in the pathogenesis of vascular calcification and generated mice with SMC-specific deletion of both Scd1 and Scd2. Mice lacking both SCD1 and SCD2 in SMCs displayed severe vascular calcification with increased ER stress. Moreover, we employed shRNA library screening and radiolabeling approaches, as well as in vitro and in vivo lipidomic analysis, and determined that fully saturated phosphatidic acids such as 1,2-distearoyl-PA (18:0/18:0-PA) mediate SFA-induced lipotoxicity and vascular calcification. Together, these results identify a key lipogenic pathway in SMCs that mediates vascular calcification. PMID:26517697

  16. Saturated phosphatidic acids mediate saturated fatty acid-induced vascular calcification and lipotoxicity.

    Science.gov (United States)

    Masuda, Masashi; Miyazaki-Anzai, Shinobu; Keenan, Audrey L; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; Ntambi, James M; Kuro-O, Makoto; Miyazaki, Makoto

    2015-10-26

    Recent evidence indicates that saturated fatty acid-induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic events in the development of vascular calcification. We evaluated whether SMC-specific inhibition of SCD and the resulting SFA accumulation plays a causative role in the pathogenesis of vascular calcification and generated mice with SMC-specific deletion of both Scd1 and Scd2. Mice lacking both SCD1 and SCD2 in SMCs displayed severe vascular calcification with increased ER stress. Moreover, we employed shRNA library screening and radiolabeling approaches, as well as in vitro and in vivo lipidomic analysis, and determined that fully saturated phosphatidic acids such as 1,2-distearoyl-PA (18:0/18:0-PA) mediate SFA-induced lipotoxicity and vascular calcification. Together, these results identify a key lipogenic pathway in SMCs that mediates vascular calcification.

  17. Elastoplastic model for unsaturated, quasi-saturated and fully saturated fine soils

    Directory of Open Access Journals (Sweden)

    Lai Ba Tien

    2016-01-01

    Full Text Available In unsaturated soils, the gaseous phase is commonly assumed to be continuous. This assumption is no more valid at high saturation ratio. In that case, air bubbles and pockets can be trapped in the porous network by the liquid phase and the gas phase becomes discontinuous. This trapped air reduces the apparent compressibility of the pore fluid and affect the mechanical behavior of the soil. Although it is trapped in the pores, its dissolution can take place. Dissolved air can migrate through the pore space, either by following the flow of the fluid or by diffusion. In this context, this paper present a hydro mechanical model that separately considers the kinematics and the mechanical behavior of each fluid species (eg liquid water, dissolved air, gaseous air and the solid matrix. This new model was implemented in a C++ code. Some numerical simulations are performed to demonstrate the ability of this model to reproduce a continuous transition of unsaturated to saturated states.

  18. Transport Properties of Earth's Core

    Science.gov (United States)

    Cohen, R. E.; Zhang, P.; Xu, J.

    2016-12-01

    One of the most important parameters governing the original heat that drives all processes in the Earth is the thermal conductivity of Earth's core. Heat is transferred through the core by convection and conduction, and the convective component provides energy to drive the geodynamo. Sha and Cohen (2011) found that the electrical conductivity of solid hcp-iron was much higher than had been assumed by geophysicists, based on electronic structure computations for electron-phonon scattering (e-p) within density functional theory [1]. Thermal conductivity is related to electrical conductivity through the empirical Wiedmann-Franz law of 1853 [2]. Pozzo et al. [3] found that the high electrical conductivity of liquid iron alloys was too high for conventional dynamo models to work—there simply is not enough energy, so O'Rourke and Stevenson proposed a model driven by participation of Mg from the core [4], supported by recent experients [5]. Recent measurements by Ohta et al. show even lower resistivities than predicted by DFT e-p, and invoked a saturation model to account for this, [6] whereas, Konopkova et al. found thermal conductivities consistent with earlier geophysical estimates. [7] We are using first-principles methods, including dynamical mean field theory for electron-electron scattering, and highly converged e-p computations, and find evidence for strong anisotropy in solid hcp-Fe that may help explain some experimental results. The current status of the field will be discussed along with our recent results. This work is supported by the ERC Advanced grant ToMCaT, the NSF, and the Carnegie Institution for Science.[1] X. Sha and R. E. Cohen, J.Phys.: Condens.Matter 23, 075401 (2011).[2] R. Franz and G. Wiedemann, Annalen Physik 165, 497 (1853).[3] M. Pozzo, C. Davies, D. Gubbins, and D. Alfe, Nature 485, 355 (2012).[4] J. G. O'Rourke and D. J. Stevenson, Nature 529, 387 (2016).[5] J. Badro, J. Siebert, and F. Nimmo, Nature (2016).[6] K. Ohta, Y. Kuwayama, K

  19. Changes in air saturation and air water interfacial area during surfactant-enhanced air sparging in saturated sand

    Science.gov (United States)

    Kim, Heonki; Choi, Kyong-Min; Moon, Ji-Won; Annable, Michael D.

    2006-11-01

    Reduction in the surface tension of groundwater, prior to air sparging for removal of volatile organic contaminant from aquifer, can greatly enhance the air content and the extent of influence when air sparging is implemented. However, detailed information on the functional relationship between water saturation, air-water contact area induced by air sparging and the surface tension of water has not been available. In this study, the influence of adding water-soluble anionic surfactant (sodium dodecyl benzene sulfonate) into groundwater before air sparging on the air-water interfacial area and water saturation was investigated using a laboratory-scale sand packed column. It was found that water saturation decreases with decreasing surface tension of water until it reaches a point where this trend is reversed so that water saturation increases with further decrease in the surface tension. The lowest water saturation of 0.58 was achieved at a surface tension of 45.4 dyn/cm, which is considered as the optimum surface tension for maximum de-saturation for the initially water-saturated sand used in this study. The air-water contact area generated in the sand column due to air sparging was measured using a gaseous interfacial tracer, n-decane, and was found to monotonically increase with decreasing water saturation. The results of this study provide useful design information for surfactant-enhanced air sparging removal of volatile contaminants from aquifers.

  20. Lunar Core and Tides

    Science.gov (United States)

    Williams, J. G.; Boggs, D. H.; Ratcliff, J. T.

    2004-01-01

    Variations in rotation and orientation of the Moon are sensitive to solid-body tidal dissipation, dissipation due to relative motion at the fluid-core/solid-mantle boundary, and tidal Love number k2 [1,2]. There is weaker sensitivity to flattening of the core-mantle boundary (CMB) [2,3,4] and fluid core moment of inertia [1]. Accurate Lunar Laser Ranging (LLR) measurements of the distance from observatories on the Earth to four retroreflector arrays on the Moon are sensitive to lunar rotation and orientation variations and tidal displacements. Past solutions using the LLR data have given results for dissipation due to solid-body tides and fluid core [1] plus Love number [1-5]. Detection of CMB flattening, which in the past has been marginal but improving [3,4,5], now seems significant. Direct detection of the core moment has not yet been achieved.