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Sample records for magnetometer towed array

  1. Adaption of the Magnetometer Towed Array geophysical system to meet Department of Energy needs for hazardous waste site characterization

    SciTech Connect

    Cochran, J.R.; McDonald, J.R.; Russell, R.J.; Robertson, R.; Hensel, E.

    1995-10-01

    This report documents US Department of Energy (DOE)-funded activities that have adapted the US Navy`s Surface Towed Ordnance Locator System (STOLS) to meet DOE needs for a ``... better, faster, safer and cheaper ...`` system for characterizing inactive hazardous waste sites. These activities were undertaken by Sandia National Laboratories (Sandia), the Naval Research Laboratory, Geo-Centers Inc., New Mexico State University and others under the title of the Magnetometer Towed Array (MTA).

  2. A surface-towed vector magnetometer

    NASA Astrophysics Data System (ADS)

    Gee, J. S.; Cande, S. C.

    2002-07-01

    We have tested the feasibility of using a commercial motion sensor as a vector magnetometer that can be towed at normal survey speeds behind a research vessel. In contrast to previous studies using a shipboard mounted vector magnetometer, the towed system is essentially unaffected by the magnetization of the towing vessel. Results from a test deployment compare favorably with an earlier vector aeromagnetic survey, indicating that the towed instrument can resolve horizontal and vertical anomalies with amplitudes >30-50 nT. This instrument should be particularly useful in equatorial regions, where the vector anomalies are substantially greater than the corresponding total field anomalies.

  3. Towed and Shipboard Vector Magnetometers in Marine Geophysics

    NASA Astrophysics Data System (ADS)

    Barckhausen, U.; Engels, M.

    2011-12-01

    The use of vector magnetometer components in geomagnetics has many advantages compared to the use of total field magnetometers. However, in marine geophysics the robust and easy-to-use Proton Precession magnetometers are still the standard instruments. Most of the few vector magnetometers in use work on multi instrument deep submersible platforms. Here we present some new instrumental and methodological aspects of surface towed fluxgate vector magnetometers which we use in a combination with Overhauser sensors. Processed fluxgate total field data are practically identical to the Overhauser reference and even provide a reliable gradient when combined with one Overhauser.The vertical component derived from the vector data constrains 2-D modelling much better than the total field alone. Although towed vector magnetometers typically provide no independent estimate of yaw, we illustrate that a numerical yaw (bandpass filtered magnetic heading) can provide reasonable estimates of the horizontal field components. These component data open additional analysis tools: the strike direction of magnetic lineations can be estimated from single profiles by either magnetic boundary strike ellipses in the space domain or by coherences between vertical and horizontal components in the wavenumber domain. Auto power spectra of the total field provide an approximate depth to the anomaly source or, if in obvious contradiction to the bathymetric depth, allow the detection of distortions, for example, by external temporal geomagnetic variations. A more common application is the use of vector magnetometers as shipboard instruments where the sensor's orientation can easily be resolved with data from the ship's positioning systems. We present some comparisons of shipboard and towed vector data. The quality of the magnetic data recorded onboard the ship can be surprisingly good after a thorough compensation for the ship's magnetic field.

  4. Optical magnetometer array for fetal magnetocardiography

    PubMed Central

    Wyllie, Robert; Kauer, Matthew; Wakai, Ronald T.; Walker, Thad G.

    2012-01-01

    We describe an array of spin-exchange-relaxation-free optical magnetometers designed for detection of fetal magnetocardiography (fMCG). The individual magnetometers are configured with a small volume with intense optical pumping, surrounded by a large pump-free region. Spin-polarized atoms that diffuse out of the optical pumping region precess in the ambient magnetic field and are detected by a probe laser. Four such magnetometers, at the corners of a 7 cm square, are configured for gradiometry by feeding back the output of one magnetometer to a field coil to null uniform magnetic field noise at frequencies up to 200 Hz. We present the first measurements of fMCG signals using an atomic magnetometer. PMID:22739870

  5. Fetal Magnetocardiography with an Atomic Magnetometer Array

    NASA Astrophysics Data System (ADS)

    Sulai, Ibrahim; Deland, Zack; Wahl, Colin; Wakai, Ronald; Walker, Thad

    2014-05-01

    Fetal magnetocardiography (fMCG) is a powerful technique for analyzing the heartbeat patterns of inutero fetuses. We present results from our array of four Spin-Exchange Relaxation-Free (SERF) rubidium-87 atomic magnetometers which has been used to detect and create these magnetocardiograms. We have demonstrated a magnetic noise sensitivity of < 10 fT /√{ Hz} , limited by the Johnson noise of the magnetically-shielded room. We discuss new design features and experimental practices that have increased our sensitivity and allowed us to successfully measure an fMCG at a gestational age of only 21 weeks. We hope to eventually apply these techniques to the detection and diagnosis of heartbeat arrhythmias, which, if detected early enough, can be treated inutero . This work is supported by the National Institutes of Health.

  6. Sensor evaluation study for use with towed arrays for UXO site characterization

    SciTech Connect

    McDonald, J.R.; Robertson, R.

    1996-11-01

    The Naval Research Laboratory is developing a Multi-sensor Towed Array Detection System (MTADS) with support from the DOD Environmental Security Technology Certification Program (ESTCP). In this effort we seek to extend and refine ordnance detection technology to more efficiently characterize OEW sites, identifying nonferrous and smaller items, distinguishing ordnance from clutter and analyzing clustered targets to identify and locate individual targets within complex target fields. Our evaluation shows that these goals are best met by combining magnetic and electromagnetic sensors. We report on field studies at a prepared test range of commercial sensors in arrays in various configurations and including; Cesium vapor magnetometers in single sensor and gradiometric configurations, fluxgate gradiometers, proton procession magnetometers, and electromagnetic pulsed induction sensors. The advantages and disadvantages of each technology and their applicability based upon survey requirements is discussed. We also discuss recommended data densities including horizontal sensor spacings, survey speeds, sensor heights and make recommendations about the appropriate use of gradiometers and active sensors.

  7. Adaptive beamforming of a towed array during maneuvering

    NASA Astrophysics Data System (ADS)

    Gong, Zaixiao; Lin, Peng; Guo, Yonggang; Zhang, Renhe; Li, Fenghua

    2012-11-01

    During maneuvering, the performance of Minimum Variance Distortion-less Response (MVDR) beamforming for a towed hydrophone array will greatly degrade due to shape error. Under the assumption that the shape of a towed array changes in a known way during the observation interval, an improved MVDR method is proposed. A static array with average shape during the observation interval is taken as a reference array shape. The phase difference of the cross spectral density matrix (CSDM) between the time-varying array and the reference array is compensated on each azimuth. A coherent CSDM accumulation can then be achieved. Experimental results show that the improved MVDR method can yield better performance than conventional MVDR with a time-varying array. This helps to resolve the problems of left-right target ambiguity and weak signal detection for time-varying arrays.

  8. Fetal MCG with Atomic Magnetometer Array

    NASA Astrophysics Data System (ADS)

    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.

  9. The World's Largest Real Time Magnetometer Array: MAGDAS

    NASA Astrophysics Data System (ADS)

    Maeda, G.; Yumoto, K.; Abe, S.; Uozumi, T.

    2009-12-01

    This poster briefly out lines the current situation of the world's largest real time magnetometer array: MAGDAS. This array was conceived by Professor K. Yumoto of the Space Environment Research Center (SERC) based at Kyushu University in Japan. The first phase of MAGDAS deployment coincided with IHY (Years 2005-2009) and about 50 units were installed all over the world. The second phase of MAGDAS deployment is set to occur during ISWI (Intl. Space Weather Initiative, Years 2010-2012) using a new set of 50 magnetometers. MAGDAS stations are concentrated in three chains: (1) the 210 deg. MM chain through Asia, (2) the 96 deg. MM chain through Africa, and (3) the Dip Equator Chain. Data from MAGDAS is available to the scientific community but some conditions are attached to the data. We explain those conditions.

  10. All-weather vehicle classification using magnetometer arrays

    NASA Astrophysics Data System (ADS)

    Casalegno, James W.

    2002-08-01

    Arrays of vector magnetometers employing matched field processing have demonstrated the ability to accurately detect, track, and characterize the magnetic signature of vehicles traveling within range of the sensor field, regardless of weather conditions. This processing works on all types of vehicles, including passenger cars, light trucks, tractor-trailers, tanks, armored personnel carriers, etc. Consistency among the magnetic dipole estimates from similar vehicles has led to investigations of the ability to classify using magnetic information obtained from this process. Preliminary results suggest that separation of the permanent and induced portions of a vehicle's magnetic moment can provide the basis for an accurate, all-weather vehicle classifier.

  11. Deep water towed array measurements at close range.

    PubMed

    Heaney, Kevin D; Campbell, Richard L; Murray, James J; Baggeroer, Arthur B; Scheer, Eddie K; Stephen, Ralph A; D'Spain, Gerald L; Mercer, James A

    2013-10-01

    During the North Pacific Acoustic Laboratory Philippine Sea 2009 experiment, towed array receptions were made from a towed source as the two ships transited from a separation of several Convergence Zones through a Closest Point of Approach at 3 km. A combination of narrowband tones and broadband pulses were transmitted covering the frequency band 79-535 Hz. The received energy arrives from two general paths-direct path and bottom bounce. Bearing-time records of the narrowband arrivals at times show a 35° spread in the angle of arrival of the bottom bounce energy. Doppler processing of the tones shows significant frequency spread of the bottom bounce energy. Two-dimensional modeling using measured bathymetry, a geoacoustic parameterization based upon the geological record, and measured sound-speed field was performed. Inclusion of the effects of seafloor roughness and surface waves shows that in-plane scattering from rough interfaces can explain much of the observed spread in the arrivals. Evidence of out-of-plane scattering does exist, however, at short ranges. The amount of out-of-plane scattering is best observed in the broadband impulse-beam response analysis, which in-plane surface roughness modeling cannot explain. PMID:24116519

  12. Real-time threat detection using magnetometer arrays

    NASA Astrophysics Data System (ADS)

    Prouty, Mark D.; Tchernychev, Mikhail

    2016-05-01

    In this paper we present a discussion of using an array of atomic magnetometers to locate the presence of ferrous materials, such as concealed weapons, in real time. Ferrous materials create magnetic field anomalies. In order to determine the location of such objects, readings from many positions must be analyzed. This field inversion is typically done in post processing, once readings over a survey area or region of interest have been gathered. With the recent development of small and low power sensors, the dozen or so sensors required to provide information for magnetic field inversion may be deployed. We have built such an array and present here the results of using a realtime inversion algorithm. The inversion algorithm accurately determines target properties at a rate of 10 times per second as objects move past the array. Accuracies are as good as those obtained with target inversion methods used in analyzing data for unexploded ordnance detection. While those methods are typically applied in post processing, we show here those methods work even better when applied in real-time. We further present some analyses of the predicted performance of arrays in various geometries to address issues in security, such as crowd or perimeter monitoring. Target inversion methods may be accurately simulated, allowing for the development and testing of algorithms in an efficient manner. Additional processing may be done using the time history of the inversion results to remove false alarms and enhance detection. The key step is to start with an inversion method, utilizing the mathematical properties of magnetic fields and the known geometry of the measurements.

  13. MAGNETOMETER

    DOEpatents

    Leavitt, M.A.

    1958-11-18

    A magnetometer ls described, partlcularly to a device which accurately indicates the polarity and intensity of a magnetlc field. The main feature of the invention is a unique probe construction in combinatlon wlth a magnetic fleld detector system. The probe comprises two coils connected in series opposition for energization with an a-c voltage. The voltage lnduced in a third coll on the probe, a pick-up coil, is distorted by the presence of an external field to produce even harmonic voltages. A controlled d-c current is passed through the energized coils to counter the dlstortlon and reduce tbe even harmonic content to a null. When the null point is reached, the d-c current is a measure of the external magnetic field strength, and the phase of the pickup coil voltage indicates tbe field polarlty.

  14. Magnetocardiography with a modular spin-exchange relaxation free atomic magnetometer array

    PubMed Central

    Wyllie, R; Kauer, M; Smetana, G S; Wakai, R T; Walker, T G

    2012-01-01

    We present a portable four-channel atomic magnetometer array operating in the spin exchange relaxation-free regime. The magnetometer array has several design features intended to maximize its suitability for biomagnetic measurement, specifically foetal magnetocardiography, such as a compact modular design and fibre coupled lasers. The modular design allows the independent positioning and orientation of each magnetometer. Using this array in a magnetically shielded room, we acquire adult magnetocadiograms. These measurements were taken with a 6–11 fT Hz−1/2 single-channel baseline sensitivity that is consistent with the independently measured noise level of the magnetically shielded room. PMID:22504066

  15. Magnetocardiography with a modular spin-exchange relaxation-free atomic magnetometer array.

    PubMed

    Wyllie, R; Kauer, M; Smetana, G S; Wakai, R T; Walker, T G

    2012-05-01

    We present a portable four-channel atomic magnetometer array operating in the spin-exchange relaxation-free regime. The magnetometer array has several design features intended to maximize its suitability for biomagnetic measurement, specifically foetal magnetocardiography, such as a compact modular design and fibre-coupled lasers. The modular design allows the independent positioning and orientation of each magnetometer. Using this array in a magnetically shielded room, we acquire adult magnetocadiograms. These measurements were taken with a 6-11 fT Hz(-1/2) single-channel baseline sensitivity that is consistent with the independently measured noise level of the magnetically shielded room. PMID:22504066

  16. 77 FR 52317 - Record of Decision for Surveillance Towed Array Sensor System Low Frequency Active Sonar

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-29

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Department of the Navy Record of Decision for Surveillance Towed Array Sensor System Low Frequency Active... Array Sensor System Low Frequency Active (SURTASS LFA) sonar systems with certain...

  17. Effect of towed array stability on instantaneous localization of marine mammals.

    PubMed

    von Benda-Beckmann, A M; Beerens, S P; van Ijsselmuide, S P

    2013-09-01

    Reliable localization of marine mammals using towed arrays is often required for mitigation, population density estimates, and bioacoustics research. The accuracy of the range estimates using towed arrays is often not well quantified. Triangulation methods using multiple hydrophones allow for fast range estimates but are sensitive to the species type, location of the animal with respect to the array, sound propagation conditions, and array stability. A simple model is presented that is used to estimate the range accuracy of towed arrays for different vocalizations and is compared to measured range accuracies of sperm whale clicks recorded with a 15 m baseline towed array. The ranging performance is particularly sensitive to hydrophone position errors which are found to dominate. Hydrophone position errors could be estimated using heading sensors placed in the array and are taken into account in the model. A good agreement is found between the empirical range errors and theoretically predicted ones. Extrapolation of the model to other species suggests that species emitting high frequency clicks and calls can be localized from distances out to a few kilometers with a baseline of 15 m, but baleen whales transmitting low frequency calls require longer baselines to obtain range estimates. PMID:23968038

  18. Tracking sperm whale (Physeter macrocephalus) dive profiles using a towed passive acoustic array

    NASA Astrophysics Data System (ADS)

    Thode, Aaron

    2004-07-01

    A passive acoustic method is presented for tracking sperm whale dive profiles, using two or three hydrophones deployed as either a vertical or large-aperture towed array. The relative arrival times between the direct and surface-reflected acoustic paths are used to obtain the ranges and depths of animals with respect to the array, provided that the hydrophone depths are independently measured. Besides reducing the number of hydrophones required, exploiting surface reflections simplifies automation of the data processing. Experimental results are shown from 2002 and 2003 cruises in the Gulf of Mexico for two different towed array deployments. The 2002 deployment consisted of two short-aperture towed arrays separated by 170 m, while the 2003 deployment placed an autonomous acoustic recorder in tandem with a short-aperture towed array, and used ship noise to time-align the acoustic data. The resulting dive profiles were independently checked using single-hydrophone localizations, whenever multipath reflections from the ocean bottom could be exploited to effectively create a large-aperture vertical array. This technique may have applications for basic research and for real-time mitigation for seismic airgun surveys.

  19. Tracking sperm whale (Physeter macrocephalus) dive profiles using a towed passive acoustic array.

    PubMed

    Thode, Aaron

    2004-07-01

    A passive acoustic method is presented for tracking sperm whale dive profiles, using two or three hydrophones deployed as either a vertical or large-aperture towed array. The relative arrival times between the direct and surface-reflected acoustic paths are used to obtain the ranges and depths of animals with respect to the array, provided that the hydrophone depths are independently measured. Besides reducing the number of hydrophones required, exploiting surface reflections simplifies automation of the data processing. Experimental results are shown from 2002 and 2003 cruises in the Gulf of Mexico for two different towed array deployments. The 2002 deployment consisted of two short-aperture towed arrays separated by 170 m, while the 2003 deployment placed an autonomous acoustic recorder in tandem with a short-aperture towed array, and used ship noise to time-align the acoustic data. The resulting dive profiles were independently checked using single-hydrophone localizations, whenever multipath reflections from the ocean bottom could be exploited to effectively create a large-aperture vertical array. This technique may have applications for basic research and for real-time mitigation for seismic airgun surveys. PMID:15295984

  20. Calibration and Thermal Analysis of a Conformal SERF Magnetometer Array for MEG Applications

    NASA Astrophysics Data System (ADS)

    Alexander, Elizabeth V.

    In magnetoencephalography (MEG), a measurement of the magnetic field produced by the brain, it is critical for the distance between the magnetometers and the brain to be small and unchanging. Limitations of SQUIDs, the magnetometers used in most MEG systems, make this requirement difficult to meet. SERF magnetometers have been proposed as an alternative technology for use in more portable and flexible MEG systems. This research considers two of the challenges associated with an array of SERF magnetometers attached to a conformal cap. First, for meaningful measurements in MEG, it is important for the locations and orientations of magnetometers to be known. This information can be estimated using the magnetometers' measurements of a known magnetic field produced by a configuration of magnetic dipoles, but the estimation algorithm is extremely sensitive to the dipole configuration. This thesis introduces a graphical tool to assess the quality of a configuration of magnetic dipoles. Second, the core of SERF magnetometers has a high operating temperature. This work finds a thermal insulation layout that allows for a small overall magnetometer package size while maintaining proper operation temperature and preventing thermal injury to a patient.

  1. The development of a multichannel atomic magnetometer array for fetal magnetocardiography

    NASA Astrophysics Data System (ADS)

    Wylie, Robert, IV

    Biomagnetic signals can provide important information about electrical processes in the human body. Because of the small signal sizes, magnetic detection is generally used where other detection methods are incomplete or insufficiently sensitive. One important example is fetal magnetocardiography (fMCG), where the detection of magnetic signals is currently the only available technique for certain clinical applications, such as the detection of cardiac arrhythmia. Until now, magnetometers based on superconducting quantum interference devices (SQUIDs), which can operate at sensitivities down to 1 fT Hz-1/2 have been the only option. The low Tc superconductors and associated cryogenics required for the most sensitive devices has led to interest in alternative technologies. In the last decade, atomic magnetometers operating in the spin-exchange relaxation-free (SERF) regime have demonstrated a higher sensitivity than SQUIDs while operating near room temperature. Though large SERF magnetometer arrays have not yet been built, smaller arrays should be sufficient for applications such as fMCG. In this thesis, we present the design and characterization of a portable four-channel SERF atomic magnetometer array with a 5-10 fT Hz-1/2 single channel baseline sensitivity. The magnetometer array has several design features intended to maximize its suitability for biomagnetic measurement, specifically fMCG, such as a compact modular design and large, flexible channel spacing from 5-15 cm. The modular design allows for easily adding units to the array and the independent positioning and orientation of each magnetometer, in principle allowing for non-planar array geometries. Using this array in a magnetically shielded room, we acquire adult magnetocadiograms and, for the first time with a SERF magnetometer, fMCG. We also investigate the use of different operational modes of the magnetometer to extend its functionality, specifically modulation methods for additional directional

  2. A simple deep-towed vertical array for high-resolution reflection seismic profiling

    NASA Astrophysics Data System (ADS)

    Herber, R.; Nuppenau, V.; Weigel, W.; Wong, H. K.

    1986-06-01

    A simple, low cost, deep-towed system for high-resolution reflection seismic profiling is described. It consists of a vertical array with two hydrophones having a separation of 2.2 m and rigidly mounted onto streamlined tow bodies. Improvement of the signal-to-noise ratio is attained by simple stacking of the hydrophone outputs after signal conditioning and travel time corrections. The suppression of side echoes and surface reflections is achieved by an analog procedure which in effect improves the directional characteristics of the array. A circuit for automatic gain control is included to enhance weak signals as well as to suppress ringing. Results in Kiel Bay and over the crest of the Jan Mayen Ridge (northern Atlantic) suggest that this simple vertical array may supplement air gun systems better than conventional, surface pinger-type equipment.

  3. Subarray partitions of large aperture planar towed arrays

    NASA Astrophysics Data System (ADS)

    Watson, Jennifer A.; Baggeroer, Arthur B.; Zurk, Lisa M.; Tracey, Brian H.

    2002-05-01

    The current focus of passive detection and localization is in littoral regions where acoustic propagation becomes complicated by severe bottom interaction. The resultant high-transmission loss motivates the need for high-array gain for effective performance over long ranges. Large planar seismic arrays, with aperture dimensions upwards of 3 km×0.5 km, have potential to achieve high gain and good resolution when using matched field processing. In realistic environments, however, large arrays are suceptible to signal gain degradation mechanisms, particularly due to spatial decorrelation of the signal and non-stationary environments. One approach to overcoming this is partitioning the array. Subarray processing reduces stationarity requirements and extracts optimum coherent gain, thus achieving higher gain than that of smaller arrays. This work examines criteria for partitioning planar arrays to perform localization using MFP. Trade-offs between spatial resolution, array gain, and resilience to motion will be quantified and discussed. Performance of different subarray geometries will be presented using adaptive and conventional MFP. [Work sponsored by DARPA under Air Force Contract No. F1962800-00-C-0002. Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endorsed by the Department of Defense. AB's work was supported by ONR through the SECNAV CNO Chair.

  4. An efficient method for tracking a magnetic target using scalar magnetometer array.

    PubMed

    Fan, Liming; Kang, Chong; Zhang, Xiaojun; Zheng, Quan; Wang, Ming

    2016-01-01

    The position of a magnetic target can be obtained through magnetic anomaly which is measured by a magnetic sensor. Comparing with vector magnetic sensor, the measurement value of the scalar magnetic sensor is almost not influenced by its orientation in measurement coordinate axes. Therefore, scalar magnetic sensors can be easily assembled into an array. Based on analysis of the total scalar magnetic anomaly measured by scalar magnetometer, we present an efficient method for tracking a magnetic target using scalar magnetometer array. In this method, we separate the position information and magnetic moment information of magnetic target by matrix transformation. Then, we can obtain the position of the magnetic target in real time by a scalar magnetometer array and a particle swarm optimization algorithm. In addition, the magnetic moment of the target can be estimated when the target's position had been calculated. The simulation shows that the position of the target can be calculated accurately and the relative error of the position is <5 %. The calculated magnetic moment of the target is close to the theoretical value. In addition, execution time of each calculation is <1 s. Thus, the position of the magnetic target can be obtained in real-time through this method. PMID:27186466

  5. Geophysical Institute Magnetometer Array: Magnetic Field Data in Real-Time for Researchers

    NASA Astrophysics Data System (ADS)

    Wolf, V. G.; Hampton, D. L.

    2012-12-01

    Magnetometer data from eight remote stations across Alaska have been collected continuously since the early 1980's by the Geophysical Institute Magnetometer Array (GIMA). These three-axis, 1Hz data, with ~ 1 nT precision, are used to determine the currents associated with auroral activity in the Alaska polar regions. A primary function of the GIMA is to supply magnetic field deflection data in real time to researchers so they can determine when to launch a sub-orbital sounding rocket from the Poker Flat Research Range into the proper auroral conditions. The aurora is a key coupling mechanism between the Earth's magnetosphere and ionosphere, and the magnetometers are used to remotely sense the ionospheric currents associated with aurora. The real-time magnetometer data are displayed through a web-based interface that functions on desktop and mobile devices. The displays are highly configurable to allow researchers the flexibility to interpret the magnetic signature they need to make a successful launch decision. The data are also available for download within 24 hours of collection. The existence of real-time data has been and will continue to be critical for successful rocket launches, however the real-time system needs to improve to meet the ever growing needs of the user community. Planned upgrades will improve the reliability and resolution of the displays as well as the ease of data download, and integration into NASA virtual observatories.

  6. Comparing passive source localization and tracking approaches with a towed horizontal receiver array in an ocean waveguide.

    PubMed

    Gong, Zheng; Tran, Duong D; Ratilal, Purnima

    2013-11-01

    Approaches for instantaneous passive source localization using a towed horizontal receiver array in a random range-dependent ocean waveguide are examined. They include: (1) Moving array triangulation, (2) array invariant, (3) bearings-only target motion analysis in modified polar coordinates via the extended Kalman filter, and (4) bearings-migration minimum mean-square error. These methods are applied to localize and track a vertical source array deployed in the far-field of a towed horizontal receiver array during the Gulf of Maine 2006 Experiment. The source transmitted intermittent broadband pulses in the 300 to 1200 Hz frequency range. A nonlinear matched-filter kernel designed to replicate the acoustic signal measured by the receiver array is applied to enhance the signal-to-noise ratio. The source localization accuracy is found to be highly dependent on source-receiver geometry and the localization approach. For a relatively stationary source drifting at speeds much slower than the receiver array tow-speed, the mean source position can be estimated by moving array triangulation with less than 3% error near broadside direction. For a moving source, the Kalman filter method gives the best performance with 5.5% error. The array invariant is the best approach for localizing sources within the endfire beam of the receiver array with 7% error. PMID:24180781

  7. Fetal magnetocardiography measurements with an array of microfabricated optically pumped magnetometers

    NASA Astrophysics Data System (ADS)

    Alem, Orang; Sander, Tilmann H.; Mhaskar, Rahul; LeBlanc, John; Eswaran, Hari; Steinhoff, Uwe; Okada, Yoshio; Kitching, John; Trahms, Lutz; Knappe, Svenja

    2015-06-01

    Following the rapid progress in the development of optically pumped magnetometer (OPM) technology for the measurement of magnetic fields in the femtotesla range, a successful assembly of individual sensors into an array of nearly identical sensors is within reach. Here, 25 microfabricated OPMs with footprints of 1 cm3 were assembled into a conformal array. The individual sensors were inserted into three flexible belt-shaped holders and connected to their respective light sources and electronics, which reside outside a magnetically shielded room, through long optical and electrical cables. With this setup the fetal magnetocardiogram of a pregnant woman was measured by placing two sensor belts over her abdomen and one belt over her chest. The fetal magnetocardiogram recorded over the abdomen is usually dominated by contributions from the maternal magnetocardiogram, since the maternal heart generates a much stronger signal than the fetal heart. Therefore, signal processing methods have to be applied to obtain the pure fetal magnetocardiogram: orthogonal projection and independent component analysis. The resulting spatial distributions of fetal cardiac activity are in good agreement with each other. In a further exemplary step, the fetal heart rate was extracted from the fetal magnetocardiogram. Its variability suggests fetal activity. We conclude that microfabricated optically pumped magnetometers operating at room temperature are capable of complementing or in the future even replacing superconducting sensors for fetal magnetocardiography measurements.

  8. Fetal magnetocardiography measurements with an array of microfabricated optically pumped magnetometers.

    PubMed

    Alem, Orang; Sander, Tilmann H; Mhaskar, Rahul; LeBlanc, John; Eswaran, Hari; Steinhoff, Uwe; Okada, Yoshio; Kitching, John; Trahms, Lutz; Knappe, Svenja

    2015-06-21

    Following the rapid progress in the development of optically pumped magnetometer (OPM) technology for the measurement of magnetic fields in the femtotesla range, a successful assembly of individual sensors into an array of nearly identical sensors is within reach. Here, 25 microfabricated OPMs with footprints of 1 cm(3) were assembled into a conformal array. The individual sensors were inserted into three flexible belt-shaped holders and connected to their respective light sources and electronics, which reside outside a magnetically shielded room, through long optical and electrical cables. With this setup the fetal magnetocardiogram of a pregnant woman was measured by placing two sensor belts over her abdomen and one belt over her chest. The fetal magnetocardiogram recorded over the abdomen is usually dominated by contributions from the maternal magnetocardiogram, since the maternal heart generates a much stronger signal than the fetal heart. Therefore, signal processing methods have to be applied to obtain the pure fetal magnetocardiogram: orthogonal projection and independent component analysis. The resulting spatial distributions of fetal cardiac activity are in good agreement with each other. In a further exemplary step, the fetal heart rate was extracted from the fetal magnetocardiogram. Its variability suggests fetal activity. We conclude that microfabricated optically pumped magnetometers operating at room temperature are capable of complementing or in the future even replacing superconducting sensors for fetal magnetocardiography measurements. PMID:26041047

  9. Operational field evaluation of the PAC-MAG man-portable magnetometer array

    NASA Astrophysics Data System (ADS)

    Keranen, Joe; Topolosky, Zeke; Schultz, Gregory; Miller, Jonathan

    2013-06-01

    Detection and discrimination of unexploded ordnance (UXO) in areas of prior conflict is of high importance to the international community and the United States government. For humanitarian applications, sensors and processing methods need to be robust, reliable, and easy to train and implement using indigenous UXO removal personnel. This paper describes system characterization, system testing, and a continental United States (CONUS) Operational Field Evaluations (OFE) of the PAC-MAG man-portable UXO detection system. System testing occurred at a government test facility in June, 2010 and December, 2011 and the OFE occurred at the same location in June, 2012. NVESD and White River Technologies personnel were present for all testing and evaluation. The PAC-MAG system is a manportable magnetometer array for the detection and characterization of ferrous UXO. System hardware includes four Cesium vapor magnetometers for detection, a Real-time Kinematic Global Position System (RTK-GPS) for sensor positioning, an electronics module for merging array data and WiFi communications and a tablet computer for transmitting and logging data. An odometer, or "hipchain" encoder, provides position information in GPS-denied areas. System software elements include data logging software and post-processing software for detection and characterization of ferrous anomalies. The output of the post-processing software is a dig list containing locations of potential UXO(s), formatted for import into the system GPS equipment for reacquisition of anomalies. Results from system characterization and the OFE will be described.

  10. Enhanced Processing for a Towed Array Using an Optimal Noise Canceling Approach

    SciTech Connect

    Sullivan, E J; Candy, J V

    2005-07-21

    Noise self-generated by a surface ship towing an array in search of a weak target presents a major problem for the signal processing especially if broadband techniques are being employed. In this paper we discuss the development and application of an adaptive noise canceling processor capable of extracting the weak far-field acoustic target in a noisy ocean acoustic environment. The fundamental idea for this processor is to use a model-based approach incorporating both target and ship noise. Here we briefly describe the underlying theory and then demonstrate through simulation how effective the canceller and target enhancer perform. The adaptivity of the processor not only enables the ''tracking'' of the canceller coefficients, but also the estimation of target parameters for localization. This approach which is termed ''joint'' cancellation and enhancement produces the optimal estimate of both in a minimum (error) variance sense.

  11. Geospace Science from Ground-based Magnetometer Arrays: Advances in Sensors, Data Collection, and Data Integration

    NASA Astrophysics Data System (ADS)

    Mann, Ian; Chi, Peter

    2016-07-01

    , acceleration, and loss of electrons in the radiation belts promise high profile science returns. Integrated, global scale data products also have potential importance and application for real-time monitoring of the space weather threats to electrical power grids from geomagnetically induced currents. Such data exploitation increasingly relies on the collaborations between multiple national magnetometer arrays to generate single data products with common file format and data properties. We review advances in geospace science which can be delivered by networks of ground-based magnetometers - in terms of advances in sensors, data collection, and data integration - including through collaborations within the Ultra-Large Terrestrial International Magnetometer Array (ULTIMA) consortium.

  12. Detection and Analysis of Low-Frequency Sperm Whale Vocalizations with a Towed Array

    NASA Astrophysics Data System (ADS)

    Bohn, Alexander

    Sperm whale vocalizations recorded during a sea test and calibration experiment in the Gulf of Maine on a single towed, horizontal, densely sampled, low-frequency (< 2500 Hz), coherent hydrophone array system are detected and analyzed for signal energy level and other characteristics. The vocalizing individuals are localized in bearing, range, and depth. An algorithm is developed to achieve automatic detection of vocalizations. This analysis is shown to have potential utility despite restriction to only the low-frequency component of the vocalizations by sampling theory. In addition, transmission loss in the New England continental shelf and slope environment is accounted for with an ocean waveguide-acoustic propagation model. Multiple averaged realizations of this model are used to estimate transmission loss as a function of range and depth for transects between the receiver array and vocalizing whales. Comparison of the vocalizations and background noise levels and the estimated transmission loss suggests the sperm whale detection range after coherent array processing exceeds 60 km in low-to-moderate sea states. Low-frequency source levels of vocalizations are estimated using the received levels and the estimated transmission loss, and applications of both this estimate and the receiver-side statistics are discussed.

  13. ULTIMA: Array of ground-based magnetometer arrays for monitoring magnetospheric and ionospheric perturbations on a global scale

    NASA Astrophysics Data System (ADS)

    Yumoto, K.; Chi, P. J.; Angelopoulos, V.; Connors, M. G.; Engebretson, M. J.; Fraser, B. J.; Mann, I. R.; Milling, D. K.; Moldwin, M. B.; Russell, C. T.; Stolle, C.; Tanskanen, E.; Vallante, M.; Yizengaw, E.; Zesta, E.

    2012-12-01

    ULTIMA (Ultra Large Terrestrial International Magnetic Array) is an international consortium that aims at promoting collaborative research on the magnetosphere, ionosphere, and upper atmosphere through the use of ground-based magnetic field observatories. ULTIMA is joined by individual magnetometer arrays in different countries/regions, and the current regular-member arrays are Australian, AUTUMN, CARISMA, DTU Space, Falcon, IGPP-LANL, IMAGE, MACCS, MAGDAS, McMAC, MEASURE, THEMIS, and SAMBA. The Chair of ULTIMA has been K. Yumoto (MAGDAS), and its Secretary has been P. Chi (McMAC, Falcon). In this paper we perform case studies in which we estimate the global patterns of (1) near-Earth currents and (2) magnetic pulsations; these phenomena are observed over wide areas on the ground, thus suitable for the aims of ULTIMA. We analyze these two phenomena during (a) quiet period and (b) magnetic storm period. We compare the differences between these two periods by drawing the global maps of the ionospheric equivalent currents (which include the effects of all the near-Earth currents) and pulsation amplitudes. For ionospheric Sq currents at low latitudes during quiet periods, MAGDAS data covering an entire solar cycle has yielded a detailed statistical model, and we can use it as a reference for the aforementioned comparison. We also estimate the azimuthal wave numbers of pulsations and compare the amplitude distribution of pulsations with the distribution of highly energetic (in MeV range) particles simultaneously observed at geosynchronous satellites.

  14. Multiplexed HTS rf SQUID magnetometer array for eddy current testing of aircraft rivet joints

    NASA Astrophysics Data System (ADS)

    Gärtner, S.; Krause, H.-J.; Wolters, N.; Lomparski, D.; Wolf, W.; Schubert, J.; Kreutzbruck, M. v.; Allweins, K.

    2002-05-01

    Using three rf SQUID magnetometers, a multiplexed SQUID array was implemented. The SQUIDs are positioned in line with 7 mm spacing and operated using one feedback electronics with sequential read out demodulation at different radio frequencies (rf). The cross-talk between SQUID channels was determined to be negligible. To show the performance of the SQUID array, eddy current (EC) measurements of aluminum aircraft samples in conjunction with a differential (double-D) EC excitation and lock-in readout were carried out. With computer-controlled continuous switching of the SQUIDs during the scan, three EC signal traces of the sample are obtained simultaneously. We performed measurements with an EC excitation frequency of 135 Hz to localize an artificial crack (sawcut flaw) of 20 mm length in an aluminum sheet with 0.6 mm thickness. The flaw was still detected when covered with aluminum of up to 10 mm thickness. In addition, measurements with varying angles between scanning direction and flaw orientation are presented.

  15. The 2011 Tohoku Tsunami observed by an array of ocean bottom electro-magnetometers

    NASA Astrophysics Data System (ADS)

    Utada, H.; Zhang, L.; Baba, K.; Liang, P.; Shimizu, H.

    2014-12-01

    Previous studies have claimed that EM sensors can be used as a type of tsunami sensor. In fact, recent studies have reported the observation of EM field variations possibly caused by devastating tsunamis including the 2011 Tohoku Tsunami. During the period from June 2010 to November 2011, we deployed a small array consisting of 4 ocean bottom electro-magnetometers (OBEMs) in the northwestern Pacific basin, about 1,000 km to the east from the epicenter, to explore the mantle structure. This array successfully recorded EM signals associated with the 2011 Tohoku Tsunami.We found that the observed EM signal propagated in the array as a wave with a phase velocity approximately equal to that of an oceanic long wave. Also, we estimated the motional impedance and tipper corresponding to the propagation direction at each site from the major components of observed EM signals and found that they were approximately equal to the phase velocities of the tsunami propagation as suggested by a simple theory. Besides, ocean bottom seismograms and tilt data show that observed EM variations were not produced by instrumental shaking. These results gave us a clear proof that observed EM signals were generated by the motional induction of the 2011 Tohoku Tsunami and therefore can be used to estimate tsunami parameters such as wave height, arrival time, and propagation direction.Then, we estimated the tsunami propagation direction from observed tsunami-induced EM fields at four seafloor sites through several methods (both single station and array analyses). Resulting frequency dependence of the propagation direction was found consistent with a source model of the 2011 Tohoku earthquake and tsunami. We also estimated the tsunami height from EM data recorded at each site, and obtained the tsunami amplitude in the array to be approximately 1 m. The same set of parameters (propagation direction and wave height) was calculated from EM signals simulated by using a tsunami flow model with a

  16. Investigating dynamical complexity in the time series of the upgraded ENIGMA magnetometer array using various entropy measures

    NASA Astrophysics Data System (ADS)

    Balasis, Georgios; Daglis, Ioannis A.; Papadimitriou, Constantinos; Melis, Nikolaos; Giannakis, Omiros; Kontoes, Charalampos

    2016-04-01

    The HellENIc GeoMagnetic Array (ENIGMA) is a network of 3 ground-based magnetometer stations in the areas of Trikala, Attiki and Lakonia in Greece that provides measurements for the study of geomagnetic pulsations, resulting from the solar wind - magnetosphere coupling. ENIGMA magnetometer array enables effective remote sensing of geospace dynamics and the study of space weather effects on the ground (i.e., Geomagnetically Induced Currents - GIC). ENIGMA contributes data to SuperMAG, a worldwide collaboration of organizations and national agencies that currently operate more than 300 ground-based magnetometers. ENIGMA is currently extended and upgraded receiving financial support through the national funding KRIPIS project and European Commission's BEYOND project. In particular, the REGPOT project BEYOND is an FP7 project that aims to maintain and expand the existing state-of-the-art interdisciplinary research potential, by Building a Centre of Excellence for Earth Observation based monitoring of Natural Disasters in south-eastern Europe, with a prospect to increase its access range to the wider Mediterranean region through the integrated cooperation with twining organizations. This study explores the applicability and effectiveness of a variety of computable entropy measures to the ENIGMA time series in order to investigate dynamical complexity between pre-storm activity and magnetic storms.

  17. Synchronization sampling method based on delta-sigma analog-digital converter for underwater towed array system

    NASA Astrophysics Data System (ADS)

    Jiang, Jia-Jia; Duan, Fa-Jie; Li, Yan-Chao; Hua, Xiang-Ning

    2014-03-01

    Synchronization sampling is very important in underwater towed array system where every acquisition node (AN) samples analog signals by its own analog-digital converter (ADC). In this paper, a simple and effective synchronization sampling method is proposed to ensure synchronized operation among different ANs of the underwater towed array system. We first present a master-slave synchronization sampling model, and then design a high accuracy phase-locked loop to synchronize all delta-sigma ADCs to a reference clock. However, when the master-slave synchronization sampling model is used, both the time-delay (TD) of messages traveling along the wired transmission medium and the jitter of the clocks will bring out synchronization sampling error (SSE). Therefore, a simple method is proposed to estimate and compensate the TD of the messages transmission, and then another effective method is presented to overcome the SSE caused by the jitter of the clocks. An experimental system with three ANs is set up, and the related experimental results verify the validity of the synchronization sampling method proposed in this paper.

  18. Synchronization sampling method based on delta-sigma analog-digital converter for underwater towed array system.

    PubMed

    Jiang, Jia-Jia; Duan, Fa-Jie; Li, Yan-Chao; Hua, Xiang-Ning

    2014-03-01

    Synchronization sampling is very important in underwater towed array system where every acquisition node (AN) samples analog signals by its own analog-digital converter (ADC). In this paper, a simple and effective synchronization sampling method is proposed to ensure synchronized operation among different ANs of the underwater towed array system. We first present a master-slave synchronization sampling model, and then design a high accuracy phase-locked loop to synchronize all delta-sigma ADCs to a reference clock. However, when the master-slave synchronization sampling model is used, both the time-delay (TD) of messages traveling along the wired transmission medium and the jitter of the clocks will bring out synchronization sampling error (SSE). Therefore, a simple method is proposed to estimate and compensate the TD of the messages transmission, and then another effective method is presented to overcome the SSE caused by the jitter of the clocks. An experimental system with three ANs is set up, and the related experimental results verify the validity of the synchronization sampling method proposed in this paper. PMID:24689606

  19. A small towed beamforming array to identify vocalizing resident killer whales ( Orcinus orca) concurrent with focal behavioral observations

    NASA Astrophysics Data System (ADS)

    Miller, Patrick J.; Tyack, Peter L.

    Investigations of communication systems benefit from concurrent observation of vocal and visible behaviors of individual animals. A device has been developed to identify individual vocalizing resident killer whales ( Orcinus orca) during focal behavioral observations. The device consists of a 2-m, 15-element hydrophone array, which is easily towed behind a small vessel, on-board multi-channel recorders, and real-time signal processing equipment. Acoustic data from the hydrophones are digitized and processed using broadband frequency-domain beamforming to yield frequency-azimuth (FRAZ) and "directo-gram" displays of arriving sounds. Based upon statistical analysis of independent portions of typical killer whale calls, the precision of the angle-of-arrival estimate ranges from ±0° to ±2.5° with a mean precision of ±1.5°. Echolocation clicks also are resolved precisely with a typical -6 dB mainlobe width of ±2.0°. Careful positioning of the array relative to the animals minimizes the effects of depth ambiguities and allows identification of individual sources in many circumstances. Several strategies for identifying vocalizing individuals are discussed and an example of a successful identification is described. Use of the array with resident killer whales did not interfere with vessel maneuverability, animal tracking, or behavioral sampling of focal individuals. This localization technique has promise for advancing the abilities of researchers to conduct unbiased behavioral and acoustic sampling of individual free-ranging cetaceans.

  20. Passive acoustic monitoring using a towed hydrophone array results in identification of a previously unknown beaked whale habitat.

    PubMed

    Yack, Tina M; Barlow, Jay; Calambokidis, John; Southall, Brandon; Coates, Shannon

    2013-09-01

    Beaked whales are diverse and species rich taxa. They spend the vast majority of their time submerged, regularly diving to depths of hundreds to thousands of meters, typically occur in small groups, and behave inconspicuously at the surface. These factors make them extremely difficult to detect using standard visual survey methods. However, recent advancements in acoustic detection capabilities have made passive acoustic monitoring (PAM) a viable alternative. Beaked whales can be discriminated from other odontocetes by the unique characteristics of their echolocation clicks. In 2009 and 2010, PAM methods using towed hydrophone arrays were tested. These methods proved highly effective for real-time detection of beaked whales in the Southern California Bight (SCB) and were subsequently implemented in 2011 to successfully detect and track beaked whales during the ongoing Southern California Behavioral Response Study. The three year field effort has resulted in (1) the successful classification and tracking of Cuvier's (Ziphius cavirostris), Baird's (Berardius bairdii), and unidentified Mesoplodon beaked whale species and (2) the identification of areas of previously unknown beaked whale habitat use. Identification of habitat use areas will contribute to a better understanding of the complex relationship between beaked whale distribution, occurrence, and preferred habitat characteristics on a relatively small spatial scale. These findings will also provide information that can be used to promote more effective management and conservation of beaked whales in the SCB, a heavily used Naval operation and training region. PMID:23968056

  1. Effects of surveillance towed array sensor system (SURTASS) low frequency active sonar on fish

    NASA Astrophysics Data System (ADS)

    Popper, Arthur N.; Halvorsen, Michele B.; Miller, Diane; Smith, Michael E.; Song, Jiakun; Wysocki, Lidia E.; Hastings, Mardi C.; Kane, Andrew S.; Stein, Peter

    2005-04-01

    We investigated the effects of exposure to Low Frequency Active (LFA) sonar on rainbow trout (a hearing non-specialist related to several endangered salmonids) and channel catfish (a hearing specialist), using an element of the standard SURTASS LFA source array. We measured hearing sensitivity using auditory brainstem response, effects on inner ear structure using scanning electron microscopy, effects on non-auditory tissues using general pathology and histopathology, and behavioral effects with video monitoring. Exposure to 193 dB re 1 microPa (rms received level) in the LFA frequency band for 324 seconds resulted in a TTS of 20 dB at 400 Hz in rainbow trout, with less TTS at 100 and 200 Hz. TTS in catfish ranged from 6 to 12 dB at frequencies from 200 to 1000 Hz. Both species recovered from hearing loss in several days. Inner ears sensory tissues appeared unaffected by acoustic exposure. Gross pathology indicated no damage to non-auditory tissues, including the swim bladder. Both species showed consistent startle responses at sound onsets and changed their position relative to the sound source during exposures. There was no fish death attributable to sound exposure even up to four days post-exposure. [Work supported by Chief of Naval Operations.

  2. Small Magnetometer

    NASA Technical Reports Server (NTRS)

    Kuhnke, Falko; Musmann, Gunter; Glassmeier, K. H.; Tsurutani, Bruce

    1995-01-01

    Small, lightweight, low-power magnetometer measures three-dimensional magnetic field. Includes three toroidal cores - one for each dimension. Exhibits high sensitivity, low zero-point drift, and low noise. Magnetometer circuit includes driver circuit and three analog signal-processing circuits. Output of analog signal-processing circuit proportional to one of components of external magnetic field.

  3. MAVEN Magnetometer

    NASA Video Gallery

    MAVEN’s dual magnetometers will allow scientists to study the interactionbetween the solar wind and the Martian atmosphere, giving us a betterunderstanding of how Mars has evolved from a warm, ...

  4. Rebecca's Magnetometer.

    NASA Astrophysics Data System (ADS)

    Hossfield, Casper H.

    I describe a McWilliams torsion-balance magnetometer I helped Arkansas high school senior Rebecca Ragat build as a science fair project. Rebecca won awards at the regional fair which qualified her to enter her magnetometer in the Arkansas State Science Fair, where she won awards from the United States Geological Survey and the United States Navy. For those interested in building a McWilliams torsion-balance magnetometer similar to Rebecca's, I have created a kit that is available through the AAVSO Solar Division. I also describe my experience as a judge at the orange County Regional Science Fair in Florida, and encourage other scientists to participate in programs that help students learn about science through hands-on experience. Offering to be a judge at your local science fair is a good way to do this.

  5. A Near-real-time Data Transport System for Selected Stations in the Magnetometer Array for Cusp and Cleft Studies (MACCS)

    NASA Astrophysics Data System (ADS)

    Engebretson, M. J.; Valentic, T. A.; Stehle, R. H.; Hughes, W. J.

    2004-05-01

    The Magnetometer Array for Cusp and Cleft Studies (MACCS) is a two-dimensional array of eight fluxgate magnetometers that was established in 1992-1993 in the Eastern Canadian Arctic from 75° to over 80° MLAT to study electrodynamic interactions between the solar wind and Earth's magnetosphere and high-latitude ionosphere. A ninth site in Nain, Labrador, extends coverage down to 66° between existing Canadian and Greenland stations. Originally designed as part of NSF's GEM (Geospace Environment Modeling) Program, MACCS has contributed to the study of transients and waves at the magnetospheric boundary and in the near-cusp region as well as to large, cooperative, studies of ionospheric convection and substorm processes. Because of the limitations of existing telephone lines to each site, it has not been possible to economically access MACCS data promptly; instead, each month's collected data is recorded and mailed to the U.S. for processing and eventual posting on a publicly-accessible web site, http://space.augsburg.edu/space. As part of its recently renewed funding, NSF has supported the development of a near-real-time data transport system using the Iridium satellite network, which will be implemented at two MACCS sites in summer 2004. At the core of the new MACCS communications system is the Data Transport Network, software developed with NSF-ITR funding to automate the transfer of scientific data from remote field stations over unreliable, bandwidth-constrained network connections. The system utilizes a store-and-forward architecture based on sending data files as attachments to Usenet messages. This scheme not only isolates the instruments from network outages, but also provides a consistent framework for organizing and accessing multiple data feeds. Client programs are able to subscribe to data feeds to perform tasks such as system health monitoring, data processing, web page updates and e-mail alerts. The MACCS sites will employ the Data Transport Network

  6. Atomic magnetometer

    DOEpatents

    Schwindt, Peter; Johnson, Cort N.

    2012-07-03

    An atomic magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to magnetically polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the magnetic field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the magnetic field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.

  7. Development of Autonomous Magnetometer Rotorcraft For Wide Area Assessment

    SciTech Connect

    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

  8. Development of autonomous magnetometer rotorcraft for wide area assessment

    SciTech Connect

    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

  9. 13. VIEW NORTHNORTHEAST OF TOW TANK FROM TOW CARRIAGE. NOTE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. VIEW NORTH-NORTHEAST OF TOW TANK FROM TOW CARRIAGE. NOTE FRAME CONSTRUCTION OF STEEL TUBING AND LEFT FRONT WHEEL DRIVE MOTOR. - NASA Langley Research Center, Seaplane Towing Channel, 108 Andrews Street, Hampton, Hampton, VA

  10. Kinetic inductance magnetometer

    NASA Astrophysics Data System (ADS)

    Luomahaara, Juho; Vesterinen, Visa; Grönberg, Leif; Hassel, Juha

    2014-09-01

    Sensing ultra-low magnetic fields has various applications in the fields of science, medicine and industry. There is a growing need for a sensor that can be operated in ambient environments where magnetic shielding is limited or magnetic field manipulation is involved. To this end, here we demonstrate a new magnetometer with high sensitivity and wide dynamic range. The device is based on the current nonlinearity of superconducting material stemming from kinetic inductance. A further benefit of our approach is of extreme simplicity: the device is fabricated from a single layer of niobium nitride. Moreover, radio frequency multiplexing techniques can be applied, enabling the simultaneous readout of multiple sensors, for example, in biomagnetic measurements requiring data from large sensor arrays.

  11. Electron-Tunneling Magnetometer

    NASA Technical Reports Server (NTRS)

    Kaiser, William J.; Kenny, Thomas W.; Waltman, Steven B.

    1993-01-01

    Electron-tunneling magnetometer is conceptual solid-state device operating at room temperature, yet offers sensitivity comparable to state-of-art magnetometers such as flux gates, search coils, and optically pumped magnetometers, with greatly reduced volume, power consumption, electronics requirements, and manufacturing cost. Micromachined from silicon wafer, and uses tunneling displacement transducer to detect magnetic forces on cantilever-supported current loop.

  12. Multi-sensor magnetoencephalography with atomic magnetometers

    PubMed Central

    Johnson, Cort N; Schwindt, P D D; Weisend, M

    2014-01-01

    The authors have detected magnetic fields from the human brain with two independent, simultaneously operating rubidium spin-exchange-relaxation-free magnetometers. Evoked responses from auditory stimulation were recorded from multiple subjects with two multi-channel magnetometers located on opposite sides of the head. Signal processing techniques enabled by multi-channel measurements were used to improve signal quality. This is the first demonstration of multi-sensor atomic magnetometer magnetoencephalography and provides a framework for developing a non-cryogenic, whole-head magnetoencephalography array for source localization. PMID:23939051

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

    SciTech Connect

    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

  14. Automated real-time monitoring of the plasmasphere by means of ground-based magnetometer arrays in Europe and South Africa

    NASA Astrophysics Data System (ADS)

    Neska, M.; Collier, A.; Heilig, B.; Jozwiak, W.; Raita, T.; Vellante, M.

    2013-12-01

    The EMMA (Europe) / SANSA (South Africa) magnetometer network created in the frame of the PLASMON project serves for determining the plasmasphere's mass distribution basing on the FLR (field line resonance) technique. This determination shall be done in a fully automated way and in real time. Current data from all stations are delivered to the PLASMON center within ca. 10 minutes. The central server performs a detection of FLR frequencies for appropriate magnetometer pairs according to the FLRID algorithm. Subsequently, the plasmasphere's mass is determined by the FLRINV algorithm. First results of the whole system's working are presented.

  15. Magnetic Gradiometer and Vector Magnetometer Survey of the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Granot, R.

    2014-12-01

    Some of the fundamental tectonic problems of the Eastern Mediterranean remain unresolved due to the extremely thick sedimentary cover (~15 km) and the lack of accurate magnetic anomaly data. We conducted a magnetic survey of the Herodotus and Levant Basins (Eastern Mediterranean) to study the nature and age of the underlying igneous crust. The towed magnetometer array consisted of two Overhauser sensors recording the total magnetic field in a longitudinal gradiometer mode, and a marine vector magnetometer. Accurate navigation together with the gradiometer data allows the separation of the magnetic signature of the lithosphere from the contributions of the external magnetic field and the geomagnetic field. Total field data in the Herodotus Basin reveal a sequence of long-wavelength NE-SW lineated anomalies (~80 nT) suggesting a deep (~20 km) 2D magnetic source layer. Analysis of the vector data shows a steady azimuth of lineations that is generally consistent with the total field anomalies. The sequence of anomalies is rather short and does not allow a unique identification. However, the continuous northward motion of the African Plate during the Paleozoic and Mesozoic result in predictable anomaly skewness patterns for the different time periods. Forward magnetic modeling best fit the observed anomalies when using Early Permian remanence directions. Altogether, these observations and analysis suggest that a Neo-Tethyan Permian oceanic crust underlies the Herodotus Basin. Two short-wavelengths and strong (~400 nT) anomalies are found in the Levant Basin, proposing rather shallow (~7 km) magnetic sources there. These anomalies spatially coincide with Mesozoic uplifted continental structures (Eratosthenes and Jonah Highs).

  16. The MASCOT Magnetometer

    NASA Astrophysics Data System (ADS)

    Herčík, David; Auster, Hans-Ulrich; Blum, Jürgen; Fornaçon, Karl-Heinz; Fujimoto, Masaki; Gebauer, Kathrin; Güttler, Carsten; Hillenmaier, Olaf; Hördt, Andreas; Liebert, Evelyn; Matsuoka, Ayako; Nomura, Reiko; Richter, Ingo; Stoll, Bernd; Weiss, Benjamin P.; Glassmeier, Karl-Heinz

    2016-01-01

    The Mobile Asteroid Scout (MASCOT) is a small lander on board the Hayabusa2 mission of the Japan Aerospace Exploration Agency to the asteroid 162173 Ryugu. Among the instruments on MASCOT is a fluxgate magnetometer, the MASCOT Magnetometer (MasMag). The magnetometer is a lightweight ( ˜280 g) and low power ( ˜0.5 W) triaxial fluxgate magnetometer. Magnetic field measurements during the landing period and during the surface operational phase shall provide information about any intrinsic magnetic field of the asteroid and its remanent magnetization. This could provide important constraints on planet formation and the thermal and aqueous evolution of primitive asteroids.

  17. Tow Tank #1

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Digging the channel for the Tow Tank. In the late 1920s, the NACA decided to investigate the aero/hydro dynamics of floats for seaplanes. A Hydrodynamics Branch was established in 1929 and special towing basin was authorized in March of that same year. Starr Truscott (the first head of the new division) described the tank in NACA TR 470: 'The N.A.C.A. tank is of the Froude type; that is, the model which is being tested is towed through still water at successive constant speeds from a carriage spanning the tank. At each constant speed the towing pull is measured, the trim and the rise, or change of draft, are recorded and, if the model is being towed at a fixed trim, the moment required to hold it there is measured and recorded.' 'The reinforced concrete basin containing the water has the following dimensions: (1) Length on water, extreme, 2,020 feet; (2) Normal width of water surface, 24 feet; (3) Normal depth of water, 12 feet; (4) Length of 12 foot depth, 1,980 feet.' The tank was dedicated on May 27, 1931. In 1936 the tank was extended to a total length of 2,960 feet. In 1959 the facility was turned over to the U.S. Navy.Published in NACA TR No. 470, 'The N.A.C.A. Tank: A High-Speed Towing Basin for Testing Models of Seaplane Floats,' by Starr Truscott, 1933.

  18. Tuned cavity magnetometer sensitivity.

    SciTech Connect

    Okandan, Murat; Schwindt, Peter

    2009-09-01

    We have developed a high sensitivity (magnetometer that utilizes a novel optical (interferometric) detection technique. Further miniaturization and low-power operation are key advantages of this magnetometer, when compared to systems using SQUIDs which require liquid Helium temperatures and associated overhead to achieve similar sensitivity levels.

  19. Atomic magnetometer for human magnetoencephalograpy.

    SciTech Connect

    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.

  20. Tow Tank #1

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Digging the channel for the Tow Tank. In the late 1920s, the NACA decided to investigate the aero/hydro dynamics of floats for seaplanes. A Hydrodynamics Branch was established in 1929 and special towing basin was authorized in March of that same year. Starr Truscott (the first head of the new division) described the tank in NACA TR 470: 'The N.A.C.A. tank is of the Froude type; that is, the model which is being tested is towed through still water at successive constant speeds from a carriage spanning the tank. At each constant speed the towing pull is measured, the trim and the rise, or change of draft, are recorded and, if the model is being towed at a fixed trim, the moment required to hold it there is measured and recorded.' 'The reinforced concrete basin containing the water has the following dimensions: (1) Length on water, extreme, 2,020 feet; (2) Normal width of water surface, 24 feet; (3) Normal depth of water, 12 feet; (4) Length of 12 foot depth, 1,980 feet.' The tank was dedicated on May 27, 1931. In 1936 the tank was extended to a total length of 2,960 feet. In 1959 the facility was turned over to the U.S. Navy.

  1. Microfabricated Optically-Pumped Magnetometers for Biomagnetic Applications

    NASA Astrophysics Data System (ADS)

    Knappe, Svenja; Alem, Orang; Sheng, Dong; Kitching, John

    2016-06-01

    We report on the progress in developing microfabricated optically-pumped magnetometer arrays for imaging applications. We have improved our sensitivities by several orders of magnitude in the last ten years. Now, our zero-field magnetometers reach noise values below 15 fT/Hz1/2. Recently, we have also developed gradiometers to reject ambient magnetic field noise. We have built several imaging arrays and validated them for biomedical measurements of brain and heart activity.

  2. Cold Atom Magnetometers

    NASA Astrophysics Data System (ADS)

    Eto, Yujiro; Sadrove, Mark; Hirano, Takuya

    Detection of weak magnetic fields with high spatial resolution is an important technology for various applications such as biological imaging, detection of MRI signals and fundamental physics. Cold atom magnetometry enables 10-11 T/ Hz sqrt{text{Hz}} sensitivities at the micron scale, that is, at the scale of a typical biological cell size. This magnetometry takes advantage of unique properties of atomic gaseous Bose-Einstein condensates with internal spin degrees of freedom. In this chapter, we first overview various state-of-the-art magnetometers, addressing their sensitivities and spatial resolutions. Then we describe properties of spinor condensates, ultracold atom magnetometers, and the latest research developments achieved in the FIRST project, especially for the detection of alternate current magnetic fields using a spin-echo-based magnetometer. We also discuss future prospects of the magnetometers.

  3. Magnetometer uses bismuth-selenide

    NASA Technical Reports Server (NTRS)

    Woollman, J. A.; Spain, I. L.; Beale, H.

    1972-01-01

    Characteristics of bismuth-selenide magnetometer are described. Advantages of bismuth-selenide magnetometer over standard magnetometers are stressed. Thermal stability of bismuth-selenide magnetometer is analyzed. Linearity of output versus magnetic field over wide range of temperatures is reported.

  4. Hall effect magnetometer

    NASA Technical Reports Server (NTRS)

    Woollam, J. A.; Beale, H. A.; Spain, I. L. (Inventor)

    1974-01-01

    A magnetometer which uses a single crystal of bismuth selenide is described. The rhombohedral crystal structure of the sensing element is analyzed. The method of construction of the magnetometer is discussed. It is stated that the sensing crystal has a positive or negative Hall coefficient and a carrier concentration of about 10 to the 18th power to 10 to the 20th power per cubic centimeter.

  5. NACA Tow Tank

    NASA Technical Reports Server (NTRS)

    1930-01-01

    L4695 shows the interior view of construction of the Tow Tank. In the late 1920s, the NACA decided to investigate the aero/hydro dynamics of floats for seaplanes. A Hydrodynamics Branch was established in 1929 and special towing basin was authorized in March of that same year. Starr Truscott (the first head of the new division) described the tank in NACA TR 470: 'The N.A.C.A. tank is of the Froude type; that is, the model which is being tested is towed through still water at successive constant speeds from a carriage spanning the tank. At each constant speed the towing pull is measured, the trim and the rise, or change of draft, are recorded and, if the model is being towed at a fixed trim, the moment required to hold it there is measured and recorded.' 'The reinforced concrete basin containing the water has the following dimensions: (1) Length on water, extreme, 2,020 feet; (2) Normal width of water surface, 24 feet; (3) Normal depth of water, 12 feet; (4) Length of 12 foot depth, 1,980 feet.' This picture shows the tank before the coving was added. This brought the rails for the carriage closer together and helped suppress waves produced by the models. The finished tank would be filled with approximately 4 million gallons of salt water pumped in from the Back River. The tank was covered by a shelter which protected the water surface. The tank was dedicated on May 27, 1931. In 1936 the tank was extended to a total length of 2,960 feet. In 1959 the facility was turned over to the U.S. Navy.

  6. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

    SciTech Connect

    Chesca, Boris John, Daniel; Mellor, Christopher J.

    2015-10-19

    A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise S{sub Φ}{sup 1/2} decreases as 1/N{sup 1/2}. Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa{sub 2}Cu{sub 3}O{sub 7}. Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for S{sub Φ}{sup 1/2} between (0.25 and 0.44) μΦ{sub 0}/Hz{sup 1/2} for temperatures in the range (77–83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10–17) mV and (0.3–2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications.

  7. The UOSAT magnetometer experiment

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.

    1982-01-01

    The magnetometer aboard the University of Surrey satellite (UOSAT) and its associated electronics are described. The basic fluxgate magnetometer employed has a dynamic range of plus or minus 8000 nT with outputs digitized by a 12-bit successive approximation A-D converter having a resolution of plus or minus 2 nT. Noise in the 3-13 Hz bandwidth is less than 1 nT. A bias field generator extends the dynamic range to plus or minus 64,000 nT with quantization steps of 8000 nT. The magnetometer experiment is expected to provide information on the secular variation of the geomagnetic field, and the decay rate of the dipole term. Special emphasis will be placed on the acquisition of real time and memory data over the poles which can be correlated with that from Magsat.

  8. Detection of brain magnetic fields with an atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Xia, Hui; Hoffman, Dan; Baranga, Andrei; Romalis, Michael

    2006-05-01

    We report detection of magnetic fields generated by evoked brain activity with an atomic magnetometer. The measurements are performed with a high-density potassium magnetometer operating in a spin-exchange relaxation free regime. Compared to SQUID magnetometers which so far have been the only detectors capable of measuring the magnetic fields from the brain, atomic magnetometers have the advantages of higher sensitivity and spatial resolution, simple multi-channel recording, and no need for cryogenics. Using a multi-channel photodetector array we recorded magnetic fields from the brain correlated with an audio tone administered with a non-magnetic earphone. The spatial map of the magnetic field gives information about the location of the brain region responding to the auditory stimulation. Our results demonstrate the atomic magnetometer as an alternative and low cost technique for brain imaging applications, without using cryogenic apparatus.

  9. Tuned optical cavity magnetometer

    DOEpatents

    Okandan, Murat; Schwindt, Peter

    2010-11-02

    An atomic magnetometer is disclosed which utilizes an optical cavity formed from a grating and a mirror, with a vapor cell containing an alkali metal vapor located inside the optical cavity. Lasers are used to magnetically polarize the alkali metal vapor and to probe the vapor and generate a diffracted laser beam which can be used to sense a magnetic field. Electrostatic actuators can be used in the magnetometer for positioning of the mirror, or for modulation thereof. Another optical cavity can also be formed from the mirror and a second grating for sensing, adjusting, or stabilizing the position of the mirror.

  10. A Web Server for MACCS Magnetometer Data

    NASA Technical Reports Server (NTRS)

    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.

  11. THOR Fluxgate Magnetometer (MAG)

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    Turbulence Heating ObserveR (THOR) is the first mission ever flown in space dedicated to plasma turbulence. The goal of the Fluxgate Magnetometer (MAG) is to measure the DC to low frequency ambient magnetic field. 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.

  12. The Magnetospheric Multiscale Magnetometers

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Anderson, B. J.; Baumjohann, W.; Bromund, K. R.; Dearborn, D.; Fischer, D.; Le, G.; Leinweber, H. K.; Leneman, D.; Magnes, W.; Means, J. D.; Moldwin, M. B.; Nakamura, R.; Pierce, D.; Plaschke, F.; Rowe, K. M.; Slavin, J. A.; Strangeway, R. J.; Torbert, R.; Hagen, C.; Jernej, I.; Valavanoglou, A.; Richter, I.

    2016-03-01

    The success of the Magnetospheric Multiscale mission depends on the accurate measurement of the magnetic field on all four spacecraft. To ensure this success, two independently designed and built fluxgate magnetometers were developed, avoiding single-point failures. The magnetometers were dubbed the digital fluxgate (DFG), which uses an ASIC implementation and was supplied by the Space Research Institute of the Austrian Academy of Sciences and the analogue magnetometer (AFG) with a more traditional circuit board design supplied by the University of California, Los Angeles. A stringent magnetic cleanliness program was executed under the supervision of the Johns Hopkins University's Applied Physics Laboratory. To achieve mission objectives, the calibration determined on the ground will be refined in space to ensure all eight magnetometers are precisely inter-calibrated. Near real-time data plays a key role in the transmission of high-resolution observations stored on board so rapid processing of the low-resolution data is required. This article describes these instruments, the magnetic cleanliness program, and the instrument pre-launch calibrations, the planned in-flight calibration program, and the information flow that provides the data on the rapid time scale needed for mission success.

  13. The IRM fluxgate magnetometer

    NASA Technical Reports Server (NTRS)

    Luehr, H.; Kloecker, N.; Oelschlaegel, W.; Haeusler, B.; Acuna, M.

    1985-01-01

    This report describes the three-axis fluxgate magnetometer instrument on board the AMPTE IRM spacecraft. Important features of the instrument are its wide dynamic range (0.1-60,000 nT), a high resolution (16-bit analog to digital conversion) and the capability to operate automatically or via telecommand in two gain states. In addition, the wave activity is monitored in all three components up to 50 Hz. Inflight checkout proved the nominal functioning of the instrument in all modes.

  14. The Voyager magnetometer boom

    NASA Technical Reports Server (NTRS)

    Miller, D. C.

    1979-01-01

    The Voyager spacecraft magnetometer experiment utilizes two sensors on a deployable boom. The boom is an Astromast. The implementation of the Astromast into the Voyager design is described along with the hardware used to hold, latch, and deploy the mast and the tests to demonstrate damping, deployment, and alignments. Several problems encountered are discussed and their solutions are given. Flight deployment and preliminary alignment results are presented. Finally, the design is evaluated in retrospect.

  15. Optical atomic magnetometer

    DOEpatents

    Budker, Dmitry; Higbie, James; Corsini, Eric P

    2013-11-19

    An optical atomic magnetometers is provided operating on the principles of nonlinear magneto-optical rotation. An atomic vapor is optically pumped using linearly polarized modulated light. The vapor is then probed using a non-modulated linearly polarized light beam. The resulting modulation in polarization angle of the probe light is detected and used in a feedback loop to induce self-oscillation at the resonant frequency.

  16. Correcting GOES-R Magnetometer Data for Stray Fields

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    Time-varying spacecraft magnetic fields or stray fields are a problem for magnetometer systems. While constant fields can be removed with zero offset 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 be a good idea, but this gradiometer solution is even more susceptible to noise than a single magnetometer. Unless the stray fields are larger than the magnetometer noise, simply averaging the two measurements is a more accurate approach. If averaging is used, it may be worthwhile to explicitly estimate and remove stray fields. Models and estimation algorithms are provided for solar array, arcjet and reaction wheel fields.

  17. Dynamic Tow Maneuver Orbital Launch Technique

    NASA Technical Reports Server (NTRS)

    Rutan, Elbert L. (Inventor)

    2014-01-01

    An orbital launch system and its method of operation use a maneuver to improve the launch condition of a booster rocket and payload. A towed launch aircraft, to which the booster rocket is mounted, is towed to a predetermined elevation and airspeed. The towed launch aircraft begins the maneuver by increasing its lift, thereby increasing the flight path angle, which increases the tension on the towline connecting the towed launch aircraft to a towing aircraft. The increased tension accelerates the towed launch aircraft and booster rocket, while decreasing the speed (and thus the kinetic energy) of the towing aircraft, while increasing kinetic energy of the towed launch aircraft and booster rocket by transferring energy from the towing aircraft. The potential energy of the towed launch aircraft and booster rocket is also increased, due to the increased lift. The booster rocket is released and ignited, completing the launch.

  18. Towed and AUV Technologies for Arctic Operations

    NASA Astrophysics Data System (ADS)

    Singh, H.; Eustice, R.; Humphris, S.; Jakuba, M.; Kunz, C.; Murphy, C.; Nakamura, K.; Reves-Sohn, R.; Roman, C.; Sato, T.; Shank, T.; Willis, C.

    2007-12-01

    equipped with a 230 kHz multibeam, a digital still camera and strobe, a magnetometer and an Eh sensor. Several drift dives were carried out with the CAMPER towed vehicle at two different sites on the Gakkel Ridge this summer and yielded considerable high definition and video imagery as well as geological and biological samples. Several dives were also carried for mapping the mid-water column and the seafloor with the two AUVs and these successfully returned water column CTD, Eh, optical backscatter, magnetic and multibeam data.

  19. Iterative Magnetometer Calibration

    NASA Technical Reports Server (NTRS)

    Sedlak, Joseph

    2006-01-01

    This paper presents an iterative method for three-axis magnetometer (TAM) calibration that makes use of three existing utilities recently incorporated into the attitude ground support system used at NASA's Goddard Space Flight Center. The method combines attitude-independent and attitude-dependent calibration algorithms with a new spinning spacecraft Kalman filter to solve for biases, scale factors, nonorthogonal corrections to the alignment, and the orthogonal sensor alignment. The method is particularly well-suited to spin-stabilized spacecraft, but may also be useful for three-axis stabilized missions given sufficient data to provide observability.

  20. Superconductive imaging surface magnetometer

    DOEpatents

    Overton, Jr., William C.; van Hulsteyn, David B.; Flynn, Edward R.

    1991-01-01

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

  1. Precessing Ferromagnetic Needle Magnetometer

    NASA Astrophysics Data System (ADS)

    Jackson Kimball, Derek F.; Sushkov, Alexander O.; Budker, Dmitry

    2016-05-01

    A ferromagnetic needle is predicted to precess about the magnetic field axis at a Larmor frequency Ω under conditions where its intrinsic spin dominates over its rotational angular momentum, N ℏ≫I Ω (I is the moment of inertia of the needle about the precession axis and N is the number of polarized spins in the needle). In this regime the needle behaves as a gyroscope with spin N ℏ maintained along the easy axis of the needle by the crystalline and shape anisotropy. A precessing ferromagnetic needle is a correlated system of N spins which can be used to measure magnetic fields for long times. In principle, by taking advantage of rapid averaging of quantum uncertainty, the sensitivity of a precessing needle magnetometer can far surpass that of magnetometers based on spin precession of atoms in the gas phase. Under conditions where noise from coupling to the environment is subdominant, the scaling with measurement time t of the quantum- and detection-limited magnetometric sensitivity is t-3 /2. The phenomenon of ferromagnetic needle precession may be of particular interest for precision measurements testing fundamental physics.

  2. Precessing Ferromagnetic Needle Magnetometer.

    PubMed

    Jackson Kimball, Derek F; Sushkov, Alexander O; Budker, Dmitry

    2016-05-13

    A ferromagnetic needle is predicted to precess about the magnetic field axis at a Larmor frequency Ω under conditions where its intrinsic spin dominates over its rotational angular momentum, Nℏ≫IΩ (I is the moment of inertia of the needle about the precession axis and N is the number of polarized spins in the needle). In this regime the needle behaves as a gyroscope with spin Nℏ maintained along the easy axis of the needle by the crystalline and shape anisotropy. A precessing ferromagnetic needle is a correlated system of N spins which can be used to measure magnetic fields for long times. In principle, by taking advantage of rapid averaging of quantum uncertainty, the sensitivity of a precessing needle magnetometer can far surpass that of magnetometers based on spin precession of atoms in the gas phase. Under conditions where noise from coupling to the environment is subdominant, the scaling with measurement time t of the quantum- and detection-limited magnetometric sensitivity is t^{-3/2}. The phenomenon of ferromagnetic needle precession may be of particular interest for precision measurements testing fundamental physics. PMID:27232012

  3. Vulcan: A deep-towed CSEM receiver

    NASA Astrophysics Data System (ADS)

    Constable, Steven; Kannberg, Peter K.; Weitemeyer, Karen

    2016-03-01

    We have developed a three-axis electric field receiver designed to be towed behind a marine electromagnetic transmitter for the purpose of mapping the electrical resistivity in the upper 1000 m of seafloor geology. By careful adjustment of buoyancy and the use of real-time monitoring of depth and altitude, we are able to deep-tow multiple receivers on arrays up to 1200 m long within 50 m of the seafloor, thereby obtaining good coupling to geology. The rigid body of the receiver is designed to reduce noise associated with lateral motion of flexible antennas during towing, and allows the measurement of the vertical electric field component, which modeling shows to be particularly sensitive to near-seafloor resistivity variations. The positions and orientations of the receivers are continuously measured, and realistic estimates of positioning errors can be used to build an error model for the data. During a test in the San Diego Trough, offshore California, inversions of the data were able to fit amplitude and phase of horizontal electric fields at three frequencies on three receivers to about 1% in amplitude and 1° in phase and vertical fields to about 5% in amplitude and 5° in phase. The geological target of the tests was a known cold seep and methane vent in 1000 m water depth, which inversions show to be associated with a 1 km wide resistor at a depth between 50 and 150 m below seafloor. Given the high resistivity (30 Ωm) and position within the gas hydrate stability field, we interpret this to be massive methane hydrate.

  4. Optically transduced MEMS magnetometer

    SciTech Connect

    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.

  5. Miniature Laser Magnetometer

    NASA Technical Reports Server (NTRS)

    Slocum, Robert; Brown, Andy

    2011-01-01

    A conceptual design has been developed for a miniature laser magnetometer (MLM) that will measure the scalar magnitude and vector components of near-Earth magnetic fields. The MLM incorporates a number of technical innovations to achieve high-accuracy and high-resolution performance while significantly reducing the size of the laser-pumped helium magnetometer for use on small satellites and unmanned aerial vehicles (UAVs). and electronics sections that has the capability of measuring both the scalar magnetic field magnitude and the vector magnetic field components. Further more, the high-accuracy scalar measurements are used to calibrate and correct the vector component measurements in order to achieve superior vector accuracy and stability. The correction algorithm applied to the vector components for calibration and the same cell for vector and scalar measurements are major innovations. The separate sensor and electronics section of the MLM instrument allow the sensor to be installed on a boom or otherwise located away from electronics and other noisy magnetic components. The MLM s miniaturization will be accomplished through the use of advanced miniaturized components and packaging methods for the MLM sensor and electronics. The MLM conceptual design includes three key innovations. The first is a new non-magnetic laser package that will allow the placement of the laser pump source near the helium cell sensing elements. The second innovation is the design of compact, nested, triaxial Braunbek coils used in the vector measurements that reduce the coil size by a factor of two compared to existing Helmholtz coils with similar field-generation performance. The third innovation is a compact sensor design that reduces the sensor volume by a factor of eight compared to MLM s predecessor.

  6. The Magsat precision vector magnetometer

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.

    1980-01-01

    This paper examines the Magsat precision vector magnetometer which is designed to measure projections of the ambient field in three orthogonal directions. The system contains a highly stable and linear triaxial fluxgate magnetometer with a dynamic range of + or - 2000 nT (1 nT = 10 to the -9 weber per sq m). The magnetometer electronics, analog-to-digital converter, and digitally controlled current sources are implemented with redundant designs to avoid a loss of data in case of failures. Measurements are carried out with an accuracy of + or - 1 part in 64,000 in magnitude and 5 arcsec in orientation (1 arcsec = 0.00028 deg).

  7. 46 CFR 11.482 - Assistance towing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... mate (pilot) of towing vessels or master or mate endorsements authorizing service on inspected vessels... license or MMC for master, mate, or operator endorsed for assistance towing is authorized to engage...

  8. Electromagnetic induction imaging with a radio-frequency atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Deans, Cameron; Marmugi, Luca; Hussain, Sarah; Renzoni, Ferruccio

    2016-03-01

    We report on a compact, tunable, and scalable to large arrays imaging device, based on a radio-frequency optically pumped atomic magnetometer operating in magnetic induction tomography modality. Imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and penetration of conductive barriers. The results presented here demonstrate the potential of a future generation of imaging instruments, which combine magnetic induction tomography and the unmatched performance of atomic magnetometers.

  9. Magnetoencephalography with a two-color pump probe atomic magnetometer.

    SciTech Connect

    Johnson, Cort N.

    2010-07-01

    The authors have detected magnetic fields from the human brain with a compact, fiber-coupled rubidium spin-exchange-relaxation-free magnetometer. Optical pumping is performed on the D1 transition and Faraday rotation is measured on the D2 transition. The beams share an optical axis, with dichroic optics preparing beam polarizations appropriately. A sensitivity of <5 fT/{radical}Hz is achieved. Evoked responses resulting from median nerve and auditory stimulation were recorded with the atomic magnetometer. Recordings were validated by comparison with those taken by a commercial magnetoencephalography system. The design is amenable to arraying sensors around the head, providing a framework for noncryogenic, whole-head magnetoencephalography.

  10. 46 CFR 15.910 - Towing vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Towing vessels. 15.910 Section 15.910 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN MANNING REQUIREMENTS Equivalents § 15.910 Towing vessels. No person may serve as a master or mate (pilot) of any towing...

  11. 46 CFR 15.910 - Towing vessels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Towing vessels. 15.910 Section 15.910 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN MANNING REQUIREMENTS Equivalents § 15.910 Towing vessels. No person may serve as a master or mate (pilot) of any towing...

  12. 46 CFR 15.910 - Towing vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Towing vessels. 15.910 Section 15.910 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN MANNING REQUIREMENTS Equivalents § 15.910 Towing vessels. No person may serve as a master or mate (pilot) of any towing...

  13. 46 CFR 15.910 - Towing vessels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Towing vessels. 15.910 Section 15.910 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN MANNING REQUIREMENTS Equivalents § 15.910 Towing vessels. No person may serve as a master or mate (pilot) of any towing...

  14. 46 CFR 15.910 - Towing vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Towing vessels. 15.910 Section 15.910 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN MANNING REQUIREMENTS Equivalents § 15.910 Towing vessels. No person may serve as a master or mate (pilot) of any towing...

  15. Lunar surface magnetometer design review

    NASA Technical Reports Server (NTRS)

    1970-01-01

    Design and fabrication parameters of a lunar surface magnetometer are discussed. Drawings and requirements for mechanical design, electronic packaging design, thermal design, quality assurance and systems testing are included.

  16. Optical Magnetometer Incorporating Photonic Crystals

    NASA Technical Reports Server (NTRS)

    Kulikov, Igor; Florescu, Lucia

    2007-01-01

    According to a proposal, photonic crystals would be used to greatly increase the sensitivities of optical magnetometers that are already regarded as ultrasensitive. The proposal applies, more specifically, to a state-of-the-art type of quantum coherent magnetometer that exploits the electromagnetically-induced-transparency (EIT) method for determining a small change in a magnetic field indirectly via measurement of the shift, induced by that change, in the hyperfine levels of resonant atoms exposed to the field.

  17. Tracking sperm whales with a towed acoustic vector sensor.

    PubMed

    Thode, Aaron; Skinner, Jeff; Scott, Pam; Roswell, Jeremy; Straley, Janice; Folkert, Kendall

    2010-11-01

    Passive acoustic towed linear arrays are increasingly used to detect marine mammal sounds during mobile anthropogenic activities. However, these arrays cannot resolve between signals arriving from the port or starboard without vessel course changes or multiple cable deployments, and their performance is degraded by vessel self-noise and non-acoustic mechanical vibration. In principle acoustic vector sensors can resolve these directional ambiguities, as well as flag the presence of non-acoustic contamination, provided that the vibration-sensitive sensors can be successfully integrated into compact tow modules. Here a vector sensor module attached to the end of a 800 m towed array is used to detect and localize 1813 sperm whale "clicks" off the coast of Sitka, AK. Three methods were used to identify frequency regimes relatively free of non-acoustic noise contamination, and then the active intensity (propagating energy) of the signal was computed between 4-10 kHz along three orthogonal directions, providing unambiguous bearing estimates of two sperm whales over time. These bearing estimates are consistent with those obtained via conventional methods, but the standard deviations of the vector sensor bearing estimates are twice those of the conventionally-derived bearings. The resolved ambiguities of the bearings deduced from vessel course changes match the vector sensor predictions. PMID:21110564

  18. Microfabricated Spin Polarized Atomic Magnetometers

    NASA Astrophysics Data System (ADS)

    Jimenez Martinez, Ricardo

    Spin polarized atomic magnetometers involve the preparation of atomic spins and their detection for monitoring magnetic fields. Due to the fact that magnetic fields are ubiquitous in our world, spin polarized atomic magnetometers are used in a wide range of applications from the detection of magnetic fields generated by the human heart and brain to the detection of nuclear magnetic resonance. In this thesis we developed microfabricated spin polarized atomic magnetometers. These sensors are based on optical pumping and spin-exchange collisions between alkali atoms and noble gases contained in microfabricated millimeter-scale vapor cells. In the first part of the thesis, we improved different features of current microfabricated optical magnetometers. Specifically, we improved the bandwidth of these devices, without degrading their magnetic field sensitivity, by broadening their magnetic resonance through spin-exchange collisions between alkali atoms. We also implemented all-optical excitation techniques to avoid problems, such as the magnetic perturbation of the environment, induced by the radio-frequency fields used in some of these sensors. In the second part of the thesis we demonstrated a microfluidic chip for the optical production and detection of hyperpolarized Xe gas through spin-exchange collisions with optically pumped Rb atoms. These devices are critical for the widespread use of spin polarized atomic magnetometers in applications requiring simple, compact, low-cost, and portable instrumentation.

  19. Cryogenic High-Sensitivity Magnetometer

    NASA Technical Reports Server (NTRS)

    Day, Peter; Chui, Talso; Goodstein, David

    2005-01-01

    A proposed magnetometer for use in a cryogenic environment would be sensitive enough to measure a magnetic-flux density as small as a picogauss (10(exp -16) Tesla). In contrast, a typical conventional flux-gate magnetometer cannot measure a magnetic-flux density smaller that about 1 microgauss (10(exp -10) Tesla). One version of this device, for operation near the low end of the cryogenic temperature range, would include a piece of a paramagnetic material on a platform, the temperature of which would be controlled with a periodic variation. The variation in temperature would be measured by use of a conventional germanium resistance thermometer. A superconducting coil would be wound around the paramagnetic material and coupled to a superconducting quantum interference device (SQUID) magnetometer.

  20. Aircraft towing feasibility study. Final report

    SciTech Connect

    Not Available

    1980-09-01

    Energy costs and availability are major concerns in most parts of the world. Many ways of increasing energy supply and reducing consumption are being proposed and investigated. One that holds considerable promise is the extended towing of aircraft between airport runways and terminal gate areas with engines shut down. This study provides a preliminary assessment of the constraints on and feasibility of extended aircraft towing. Past aircraft towing experience and the state-of-the-art in towing equipment are reviewed. Safety and operational concerns associated with aircraft towing are identified, and the benefits and costs of implementing aircraft towing at 20 major US airports are analyzed. It was concluded that extended aircraft towing is technically feasible and that substantial reductions in aircraft fuel consumption and air pollutant emissions can be achieved through its implementation. It was also concluded that, although capital and operating costs associated with towing would be increased, net savings could generally be attained at these airports. Because of the lack of past experience and the necessity of proving the cost effectiveness of the towing concept, a demonstration of the feasibility of large-scale aircraft towing is necessary. The study evaluates the suitability of the 20 study airports as potential demonstration sites and makes recommendations for the first demonstration project.

  1. Digital fluxgate magnetometer: design notes

    NASA Astrophysics Data System (ADS)

    Belyayev, Serhiy; Ivchenko, Nickolay

    2015-12-01

    We presented an approach to understanding the performance of a fully digital fluxgate magnetometer. All elements of the design are important for the performance of the instrument, and the presence of the digital feed-back loop introduces certain peculiarities affecting the noise and dynamic performance of the instrument. Ultimately, the quantisation noise of the digital to analogue converter is found to dominate the noise of the current design, although noise shaping alleviates its effect to some extent. An example of magnetometer measurements on board a sounding rocket is presented, and ways to further improve the performance of the instrument are discussed.

  2. 33 CFR 163.20 - Bunching of tows.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Bunching of tows. 163.20 Section... AND WATERWAYS SAFETY TOWING OF BARGES § 163.20 Bunching of tows. (a) In all cases where tows can be bunched, it should be done. (b) Tows navigating in the North and East Rivers of New York must be...

  3. Continuous, linearly intermixed fiber tows and composite molded article thereform

    NASA Technical Reports Server (NTRS)

    McMahon, Paul E. (Inventor); Chung, Tai-Shung (Inventor); Ying, Lincoln (Inventor)

    2000-01-01

    The instant invention involves a process used in preparing fibrous tows which may be formed into polymeric plastic composites. The process involves the steps of (a) forming a carbon fiber tow; (b) forming a thermoplastic polymeric fiber tow; (c) intermixing the two tows; and (d) withdrawing the intermixed tow for further use.

  4. Noiseless Coding Of Magnetometer Signals

    NASA Technical Reports Server (NTRS)

    Rice, Robert F.; Lee, Jun-Ji

    1989-01-01

    Report discusses application of noiseless data-compression coding to digitized readings of spaceborne magnetometers for transmission back to Earth. Objective of such coding to increase efficiency by decreasing rate of transmission without sacrificing integrity of data. Adaptive coding compresses data by factors ranging from 2 to 6.

  5. A subfemtotesla multichannel atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Kominis, I. K.; Kornack, T. W.; Allred, J. C.; Romalis, M. V.

    2003-04-01

    The magnetic field is one of the most fundamental and ubiquitous physical observables, carrying information about all electromagnetic phenomena. For the past 30 years, superconducting quantum interference devices (SQUIDs) operating at 4K have been unchallenged as ultrahigh-sensitivity magnetic field detectors, with a sensitivity reaching down to 1fTHz-1/2 (1fT = 10-15T). They have enabled, for example, mapping of the magnetic fields produced by the brain, and localization of the underlying electrical activity (magnetoencephalography). Atomic magnetometers, based on detection of Larmor spin precession of optically pumped atoms, have approached similar levels of sensitivity using large measurement volumes, but have much lower sensitivity in the more compact designs required for magnetic imaging applications. Higher sensitivity and spatial resolution combined with non-cryogenic operation of atomic magnetometers would enable new applications, including the possibility of mapping non-invasively the cortical modules in the brain. Here we describe a new spin-exchange relaxation-free (SERF) atomic magnetometer, and demonstrate magnetic field sensitivity of 0.54fTHz-1/2 with a measurement volume of only 0.3cm3. Theoretical analysis shows that fundamental sensitivity limits of this device are below 0.01fTHz-1/2. We also demonstrate simple multichannel operation of the magnetometer, and localization of magnetic field sources with a resolution of 2mm.

  6. A subfemtotesla multichannel atomic magnetometer.

    PubMed

    Kominis, I K; Kornack, T W; Allred, J C; Romalis, M V

    2003-04-10

    The magnetic field is one of the most fundamental and ubiquitous physical observables, carrying information about all electromagnetic phenomena. For the past 30 years, superconducting quantum interference devices (SQUIDs) operating at 4 K have been unchallenged as ultrahigh-sensitivity magnetic field detectors, with a sensitivity reaching down to 1 fT Hz(-1/2) (1 fT = 10(-15) T). They have enabled, for example, mapping of the magnetic fields produced by the brain, and localization of the underlying electrical activity (magnetoencephalography). Atomic magnetometers, based on detection of Larmor spin precession of optically pumped atoms, have approached similar levels of sensitivity using large measurement volumes, but have much lower sensitivity in the more compact designs required for magnetic imaging applications. Higher sensitivity and spatial resolution combined with non-cryogenic operation of atomic magnetometers would enable new applications, including the possibility of mapping non-invasively the cortical modules in the brain. Here we describe a new spin-exchange relaxation-free (SERF) atomic magnetometer, and demonstrate magnetic field sensitivity of 0.54 fT Hz(-1/2) with a measurement volume of only 0.3 cm3. Theoretical analysis shows that fundamental sensitivity limits of this device are below 0.01 fT Hz(-1/2). We also demonstrate simple multichannel operation of the magnetometer, and localization of magnetic field sources with a resolution of 2 mm. PMID:12686995

  7. An optically modulated zero-field atomic magnetometer with suppressed spin-exchange broadening

    SciTech Connect

    Jiménez-Martínez, R.; Knappe, S.; Kitching, J.

    2014-04-15

    We demonstrate an optically pumped {sup 87}Rb magnetometer in a microfabricated vapor cell based on a zero-field dispersive resonance generated by optical modulation of the {sup 87}Rb ground state energy levels. The magnetometer is operated in the spin-exchange relaxation-free regime where high magnetic field sensitivities can be achieved. This device can be useful in applications requiring array-based magnetometers where radio frequency magnetic fields can induce cross-talk among adjacent sensors or affect the source of the magnetic field being measured.

  8. Towed Twin-Fuselage Glider Launch System (CGI Animation)

    NASA Video Gallery

    The towed glider is an element of the novel rocket-launching concept of the Towed Glider Air-Launch System (TGALS). The TGALS demonstration’s goal is to provide proof-of-concept of a towed, airborn...

  9. Process for preparing tows from composite fiber blends

    NASA Technical Reports Server (NTRS)

    McMahon, Paul (Inventor); Chung, Tai-Shung (Inventor); Ying, Lincoln (Inventor)

    1989-01-01

    A continuous, substantially uniform tow useful in forming composite molded articles is prepared by forming a continuous tow of continuous carbon fibers, forming a continuous tow of thermoplastic polymer fibers to a selected width, uniformly and continuously spreading the carbon fiber two to a width that is essentially the same as the selected width for the thermoplastic polymer fiber tow, intermixing the tows intimately, uniformly and continuously, in a relatively tension-free state, and continuosuly withdrawing the intermixed tow.

  10. Observational magnetometer calibration with the Hubble Space Telescope's new magnetometers

    NASA Technical Reports Server (NTRS)

    Broude, Sidney M.

    1995-01-01

    The two magnetometers recently replaced on the Hubble Space Telescope during the STS-61 Servicing Mission are now being used successfully for Coarse Attitude Determination during spacecraft vehicle safemode recovery operation. The magnetometer alignments relative to the spacecraft's vehicle's reference frame and the magnetic coupling of the sensors to the four magnetic torquer bars were determined. Coarse Attitude determination errors are now reduced to an average of 0.6 deg. Magnetometer Sensing System calibration and Coarse Attitude determination testing with the new calibration parameters is a geometrical problem. Telemetered earth magnetic field data was collected at twenty-six different vehicle attitudes. The spacecraft attitudes selected were distributed as widely apart as possible throughout the Geocentric Inertial Coordinate reference frame. It is also desirable to sample the Earth's magnetic field over as many different locations of the spacecraft's passage over the Earth as possible, within the limitation of the +/- 28.5 deg orbital inclination. A full range of magnetic moment outputs from the torquer bars needs to be sampled, +/- 3600 ampmeters squared, as well as data when the torquer bars have zero current. Graphic utilities were also developed to visually aid in optimizing the data collection process. Finally, a brief discussion of a method for collecting data for future calibrations is suggested.

  11. Towed Subsurface Optical Communications Buoy

    NASA Technical Reports Server (NTRS)

    Stirbl, Robert C.; Farr, William H.

    2013-01-01

    The innovation allows critical, high-bandwidth submarine communications at speed and depth. This reported innovation is a subsurface optical communications buoy, with active neutral buoyancy and streamlined flow surface veins for depth control. This novel subsurface positioning for the towed communications buoy enables substantial reduction in water-absorption and increased optical transmission by eliminating the intervening water absorption and dispersion, as well as by reducing or eliminating the beam spread and the pulse spreading that is associated with submarine-launched optical beams.

  12. Eclipse - tow flight closeup and release

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This clip, running 15 seconds in length, shows the QF-106 'Delta Dart' gear down, with the tow rope secured to the attachment point above the aircraft nose. First there is a view looking back from the C-141A, then looking forward from the nose of the QF-106, and finally a shot of the aircraft being released from the tow rope. NASA Dryden Flight Research Center, Edwards, California, supported a Kelly Space and Technology, Inc. (KST)/U.S. Air Force project known as Eclipse, which demonstrated a reusable tow launch vehicle concept. The purpose of the project was to demonstrate a reusable tow launch vehicle concept that had been conceived and patented by KST. Kelly Space obtained a contract with the USAF Research Laboratory for the tow launch demonstration project under the Small Business Innovation Research (SBIR) program. The USAF SBIR contract included the modifications to turn the QF-106 into the Experimental Demonstrator #1 (EXD-01), and the C141A aircraft to incorporate the tow provisions to link the two aircraft, as well as conducting flight tests. The demonstration consisted of ground and flight tests. These tests included a Combined Systems Test of both airplanes joined by a tow rope, a towed taxi test, and six towed flights. The primary goal of the project was demonstrating the tow phase of the Eclipse concept using a scaled-down tow aircraft (C-141A) and a representative aerodynamically-shaped aircraft (QF-106A) as a launch vehicle. This was successfully accomplished. On December 20, 1997, NASA research pilot Mark Stucky flew a QF-106 on the first towed flight behind an Air Force C-141 in the joint Eclipse project with KST to demonstrate a reusable tow launch vehicle concept developed by KST. Kelly Space and Technology hoped to use the data from the tow tests to validate a tow-to-launch procedure for reusable space launch vehicles. Stucky flew six successful tow tests between December 1997 and February 6, 1998. On February 6, 1998, the sixth and final towed

  13. 77 FR 40891 - Towing Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-11

    ... regarding our public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). Docket... SECURITY Coast Guard Towing Safety Advisory Committee AGENCY: Coast Guard, DHS. ACTION: Committee Management; Notice of Open Teleconference Federal Advisory Committee Meeting. SUMMARY: The Towing...

  14. 46 CFR 11.482 - Assistance towing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... The endorsement applies to all MMCs except master and mate (pilot) of towing vessels and master or mate authorizing service on inspected vessels over 200 gross tons. Holders of any of these endorsements... assistance towing safety, equipment, and procedures. (c) The holder of a license or MMC for master, mate,...

  15. 46 CFR 11.482 - Assistance towing.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    .... The endorsement applies to all MMCs except master and mate (pilot) of towing vessels and master or mate authorizing service on inspected vessels over 200 gross tons. Holders of any of these endorsements... assistance towing safety, equipment, and procedures. (c) The holder of a license or MMC for master, mate,...

  16. 46 CFR 11.482 - Assistance towing.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    .... The endorsement applies to all MMCs except master and mate (pilot) of towing vessels and master or mate authorizing service on inspected vessels over 200 gross tons. Holders of any of these endorsements... assistance towing safety, equipment, and procedures. (c) The holder of a license or MMC for master, mate,...

  17. 46 CFR 45.185 - Tow limitations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Tow limitations. 45.185 Section 45.185 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Unmanned River Barges on Lake Michigan Routes § 45.185 Tow limitations. (a) Barges must not be manned. (b) No more...

  18. 46 CFR 45.185 - Tow limitations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Tow limitations. 45.185 Section 45.185 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Unmanned River Barges on Lake Michigan Routes § 45.185 Tow limitations. (a) Barges must not be manned. (b) No more...

  19. 46 CFR 45.185 - Tow limitations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Tow limitations. 45.185 Section 45.185 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Unmanned River Barges on Lake Michigan Routes § 45.185 Tow limitations. (a) Barges must not be manned. (b) No more...

  20. 46 CFR 45.185 - Tow limitations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Tow limitations. 45.185 Section 45.185 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Unmanned River Barges on Lake Michigan Routes § 45.185 Tow limitations. (a) Barges must not be manned. (b) No more...

  1. 46 CFR 45.185 - Tow limitations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Tow limitations. 45.185 Section 45.185 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Unmanned River Barges on Lake Michigan Routes § 45.185 Tow limitations. (a) Barges must not be manned. (b) No more...

  2. 46 CFR 11.482 - Assistance towing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Assistance towing. 11.482 Section 11.482 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN REQUIREMENTS FOR OFFICER ENDORSEMENTS Professional Requirements for Deck Officers § 11.482 Assistance towing. (a) This section...

  3. Radiation source for helium magnetometers

    NASA Technical Reports Server (NTRS)

    Slocum, Robert E. (Inventor)

    1991-01-01

    A radiation source (12) for optical magnetometers (10) which use helium isotopes as the resonance element (30) includes an electronically pumped semiconductor laser (12) which produces a single narrow line of radiation which is frequency stabilized to the center frequency of the helium resonance line to be optically pumped. The frequency stabilization is accomplished using electronic feedback (34, 40, 42, 44) to control a current sources (20) thus eliminating the need for mechanical frequency tuning.

  4. THEMIS Ground-based Magnetometers

    NASA Astrophysics Data System (ADS)

    Pierce, D.; Means, J. D.; Dearborn, D.; Russell, C. T.; Strangeway, R. J.; Mende, S.; Craig, N.; Angelopoulos, V.

    2004-05-01

    This paper describes the design and development of a fluxgate suitable for full earth's field ground measurements and to be used for the ground-based segment of the THEMIS project.. The operation of the electronics is based on a 2nd order sigma-delta technique that yields a 24 bit/axis vector value with 4ppm measurement resolution at 2Hz without the use of analog to digital converters. This digital design produces superior noise performance over more conventional techniques while dramatically increasing the resolution of the magnetic field measurement. The magnetometer system is equipped with a DAC offsetting system which by program control can offset the Earth's field in any sensor orientation. Time and position data are maintained to an accuracy of 100usec and 40 meters with a dedicated Trimble Acutime2000 GPS receiver. The magnetometer may be powered from any un-regulated DC source capable of delivering 300ma. @ +10-24VDC. All data are output via USB or RS-232 interface to LabView host software which has been developed to support either Windows or Linux operating systems.Interrogation and control of the magnetometer is available via TCP protocol through a host internet connection.

  5. HTS magnetometers for fetal magnetocardiography.

    PubMed

    Li, Z; Wakai, R T; Paulson, D N; Schwartz, B

    2004-01-01

    High temperature superconducting (HTS) SQUID sensors have adequate magnetic field sensitivity for adult magnetocardiography (MCG) measurements, but it remains to be seen how well they perform for fetal MCG (fMCG), where the heart signals are typically ten times smaller than the adult signals. In this study, we assess the performance of a prototype HTS SQUID system; namely, a three-SQUID gradiometer formed from three vertically-aligned HTS dc-SQUID magnetometers integrated into a fiberglass liquid nitrogen dewar of diameter 12.5 cm and height 30 cm. Axial gradiometers with short or long baseline, as well as a second order gradiometer, can be formed out of these magnetometers via electronic subtraction. The calibrated magnetometer sensitivities at 1 kHz are 109 fT/square root of Hz, 155 fT/square root of Hz and 51 fT/square root of Hz. Direct comparison is made between the HTS SQUID system and a LTS SQUID system by making recordings with both systems during the same session on adult and fetal subjects. Although the fMCG could be resolved with the HTS SQUID system in most near-term subjects, the signal-to-noise ratio was relatively low and the system could not be operated outside of a shielded room. PMID:16012655

  6. Magnetoencephalography with Optically Pumped Atomic Magnetometers

    NASA Astrophysics Data System (ADS)

    Schwindt, Peter; Colombo, Anthony; Jau, Yuan-Yu; Carter, Tony; Berry, Christopher; Young, Amber; McKay, Jim; Weisend, Michael

    2015-05-01

    We are working to develop a 36-channel array of optically pumped atomic magnetometers (AMs) to perform magnetoencephalography (MEG) with the goal of localizing magnetic sources within the human brain. The 36-channel array will consist of nine 4-channel sensor modules where the channels within each sensor will be spaced by 18 mm and each sensor will cover a 40 mm by 40 mm area of the head. In a previous 4-channel AM prototype, we demonstrated the measurement of evoked responses in both the auditory and somatosensory cortexes. This prototype had a 5 fT/Hz1/2 sensitivity. In the current version of the AM under development we are maintaining the previous sensitivity while implementing several improvements, including increasing the bandwidth from 20 Hz to more than 100 Hz, reducing the separation of the active volume of the AM from exterior of the sensor from 25 mm to 10 mm or less, and reducing the active sensor volume by a factor >10 to ~15 mm3. We will present results on the performance of our most recent AM prototype and progress toward developing a complete MEG system including a person-sized magnetic shield to provide a low-noise magnetic environment for MEG measurements.

  7. 33 CFR 401.34 - Vessels in tow.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Vessels in tow. 401.34 Section... TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Seaway Navigation § 401.34 Vessels in tow. No vessel that is not self-propelled (including but not limited to tug/tows and/or deadship/tows) shall be...

  8. Controlling iceberg roll/stability during towing around drillships

    SciTech Connect

    Benedict, C.P.; Lewis, J.C.; Dinn, G.J.; Learning, F.R.

    1981-01-01

    Field iceberg survey data were collected and on the basis of Lagrangian computer analysis, a large sample of simulated bergs were towed from random stable floating positions. This paper presents: the results on instrumenting iceberg tow forces on the Aquitaine site during the 1980 drilling program, and an operational procedure for predicting critical tow forces on the basis of pre-tow surveys.

  9. System Applies Polymer Powder To Filament Tow

    NASA Technical Reports Server (NTRS)

    Baucom, Robert M.; Snoha, John J.; Marchello, Joseph M.

    1993-01-01

    Polymer powder applied uniformly and in continuous manner. Powder-coating system applies dry polymer powder to continuous fiber tow. Unique filament-spreading technique, combined with precise control of tension on fibers in system, ensures uniform application of polymer powder to web of spread filaments. Fiber tows impregnated with dry polymer powders ("towpregs") produced for preform-weaving and composite-material-molding applications. System and process valuable to prepreg industry, for production of flexible filament-windable tows and high-temperature polymer prepregs.

  10. Free-Flying Magnetometer Data System

    NASA Technical Reports Server (NTRS)

    Blaes, B.; Javadi, H.; Spencer, H.

    2000-01-01

    The Free-Flying Magnetometer (FFM) is an autonomous "sensorcraft" developed at the Jet Propulsion Laboratory (JPL) for the Enstrophy sounding rocket mission. This mission was a collaborative project between the University of New Hampshire, Cornell University and JPL. The science goal of the mission was the study of current filamentation phenomena in the northern auroral region through multipoint measurements of magnetic field. The technical objective of the mission was the proof of concept of the JPL FFM design and the demonstration of an in-situ multipoint measurement technique employing many free-flying spacecraft. Four FFMs were successfully deployed from a sounding rocket launched from Poker Flats, Alaska on February 11, 1999. These hockey-puck-sized (80 mm diameter, 38 mm. height, 250 gram mass) free flyers each carry a miniature 3-axis flux-gate magnetometer that output +/- 2 V signals corresponding to a +/- 60,000 nT measurement range for each axis. The FFM uses a synchronized four-channel Sigma(Delta) Analog-to-Digital Converter (ADC) having a dynamic range of +/- 2.5V and converting at a rate of 279 samples/second/channel. Three channels are used to digitize the magnetometer signals to 17-bit (1.144 nT/bit) resolution. The fourth ADC channel is multiplexed for system monitoring of four temperature sensors and two battery voltages. The FFM also contains two sun sensors, a laser diode which emits a fan-shaped beam, a miniature S-band transmitter for direct communication to the ground station antennas, an ultra-stable Temperature Compensated Crystal Oscillator (TCXO) clock, an integrated data subsystem implemented in a Field-Programmable Gate Array (FPGA), a 4 Mbit Static Random Access Memory (SRAM) for data storage and Lithium Thionyl Chloride batteries for power. Communicating commands to the FFM prior to deployment is achieved with an infrared (IR) link. The FFM IR receiver responds to 9-bit pulse coded signals that are generated by an IR Light Emitting

  11. Deep-tow magnetic survey above large exhumed mantle domains of the eastern Southwest Indian ridge

    NASA Astrophysics Data System (ADS)

    Bronner, A.; Munschy, M.; Carlut, J. H.; Searle, R. C.; Sauter, D.; Cannat, M.

    2011-12-01

    The recent discovery of a new type of seafloor, the "smooth seafloor", formed with no or very little volcanic activity along the ultra-slow spreading Southwest Indian ridge (SWIR) shows an unexpected complexity in processes of generation of the oceanic lithosphere. There, detachment faulting is thought to be a mechanism for efficient exhumation of deep-seated mantle rocks. We present here a deep-tow geological-geophysical survey over smooth seafloor at the eastern SWIR (62-64°N) combining magnetic data, geology mapping from side-scan sonar images and results from dredge sampling. We introduce a new type of calibration approach for deep-tow fluxgate magnetometer. We show that magnetic data can be corrected from the magnetic effect of the vehicle with no recourse to its attitude (pitch, roll and heading) but only using the 3 components recorded by the magnetometer and an approximation of the scalar intensity of the Earth magnetic field. The collected dredge samples as well as the side-scan images confirm the presence of large areas of exhumed mantle-derived peridodites surrounded by a few volcanic constructions. This allows us to hypothesis that magnetic anomalies are caused by serpentinized peridotites or magmatic intrusions. We show that the magnetic signature of the smooth seafloor is clearly weaker than the surrounding volcanic areas. Moreover, the calculated magnetization of a source layer as well as the comparison between deep-tow and sea-surface magnetic data argue for strong East-West variability in the distribution of the magnetized sources. This variability may results from fluid-rocks interaction along the detachment faults as well as from the repartition of the volcanic material and thus questions the seafloor spreading origin of the corresponding magnetic anomalies. Finally, we provide magnetic arguments, as calculation of block rotation or spreading asymmetry in order to better constrain tectonic mechanisms that occur during the formation of this

  12. Helicopter attempts tow of Liberty Bell 7

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Marine helicopter appears to have Liberty Bell 7 in tow after Virgil I. Grissom's successful flight of 305 miles down the Atlantic Missile Range. Minutes after 'Gus' Grissom got out of the spacecraft, it sank.

  13. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... towing fittings and must act parallel to the ground. In addition— (1) A vertical load factor equal to 1.0...) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of...

  14. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... towing fittings and must act parallel to the ground. In addition— (1) A vertical load factor equal to 1.0...) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of...

  15. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... towing fittings and must act parallel to the ground. In addition— (1) A vertical load factor equal to 1.0...) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of...

  16. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... towing fittings and must act parallel to the ground. In addition— (1) A vertical load factor equal to 1.0...) A reaction with a maximum value equal to the vertical reaction must be applied at the axle of...

  17. 14 CFR 25.509 - Towing loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... wheel to which the load is applied. Enough airplane inertia to achieve equilibrium must be applied. (ii) The loads must be reacted by airplane inertia. (d) The prescribed towing loads are as follows:...

  18. Computational Analysis of Towed Ballute Interactions

    NASA Technical Reports Server (NTRS)

    Gnoffo, Peter A.; Anderson, Brian P.

    2002-01-01

    A ballute (balloon-parachute) is an inflatable, aerodynamic drag device for application to planetary entry vehicles. Ballutes may be directly attached to a vehicle, increasing its cross-sectional area upon inflation, or towed behind the vehicle as a semi-independent device that can be quickly cut free when the requisite change in velocity is achieved. The aerothermodynamics of spherical and toroidal towed ballutes are considered in the present study. A limiting case of zero towline length (clamped system) is also considered. A toroidal system can be designed (ignoring influence of the tethers) such that all flow processed by the bow shock of the towing spacecraft passes through the hole in the toroid. For a spherical ballute, towline length is a critical parameter that affects aeroheating on the ballute being towed through the spacecraft wake. In both cases, complex and often unsteady interactions ensue in which the spacecraft and its wake resemble an aero spike situated in front of the ballute. The strength of the interactions depends upon system geometry and Reynolds number. We show how interactions may envelope the base of the towing spacecraft or impinge on the ballute surface with adverse consequences to its thermal protection system. Geometric constraints to minimize or eliminate such adverse interactions are discussed. The towed, toroidal system and the clamped, spherical system show greatest potential for a baseline design approach.

  19. A Complete Cubesat Magnetometer System Project

    NASA Technical Reports Server (NTRS)

    Zesta, Eftyhia

    2014-01-01

    The objective of this work is to provide the center with a fully tested, flexible, low cost, miniaturized science magnetometer system applicable to small satellite programs, like Cubesats, and to rides of opportunity that do not lend themselves to the high integration costs a science magnetometer on a boom necessitates.

  20. Construction of an alternating gradient magnetometer

    NASA Technical Reports Server (NTRS)

    Garland, Michael M.

    1988-01-01

    A magnetometer is described which was constructed to facilitate the study and characterization of the magnetic properties of high transition temperature superconductors. This instrument was used to measure the dc magnetic susceptibility of several superconducting compounds as a function of temperature. The construction of the magnetometer and the operating parameters are discussed in detail.

  1. High Sensitivity Optically Pumped Quantum Magnetometer

    PubMed Central

    Tiporlini, Valentina; Alameh, Kamal

    2013-01-01

    Quantum magnetometers based on optical pumping can achieve sensitivity as high as what SQUID-based devices can attain. In this paper, we discuss the principle of operation and the optimal design of an optically pumped quantum magnetometer. The ultimate intrinsic sensitivity is calculated showing that optimal performance of the magnetometer is attained with an optical pump power of 20 μW and an operation temperature of 48°C. Results show that the ultimate intrinsic sensitivity of the quantum magnetometer that can be achieved is 327 fT/Hz1/2 over a bandwidth of 26 Hz and that this sensitivity drops to 130 pT/Hz1/2 in the presence of environmental noise. The quantum magnetometer is shown to be capable of detecting a sinusoidal magnetic field of amplitude as low as 15 pT oscillating at 25 Hz. PMID:23766716

  2. Four-channel optically pumped atomic magnetometer for magnetoencephalography.

    PubMed

    Colombo, Anthony P; Carter, Tony R; Borna, Amir; Jau, Yuan-Yu; Johnson, Cort N; Dagel, Amber L; Schwindt, Peter D D

    2016-07-11

    We have developed a four-channel optically pumped atomic magnetometer for magnetoencephalography (MEG) that incorporates a passive diffractive optical element (DOE). The DOE allows us to achieve a long, 18-mm gradiometer baseline in a compact footprint on the head. Using gradiometry, the sensitivities of the channels are < 5 fT/Hz1/2, and the 3-dB bandwidths are approximately 90 Hz, which are both sufficient to perform MEG. Additionally, the channels are highly uniform, which offers the possibility of employing standard MEG post-processing techniques. This module will serve as a building block of an array for magnetic source localization. PMID:27410816

  3. Towed body measurements of flow noise from a turbulent boundary layer under sea conditions.

    PubMed

    Abshagen, J; Nejedl, V

    2014-02-01

    Results from an underwater experiment under sea conditions on flow noise beneath a flat-plate turbulent boundary layer are presented. The measurements were performed with a towed body at towing speeds U=2.3,…,6.1 m/s and depths h=-150,…,-100 m. Flow noise is measured with a linear array of equally spaced hydrophones (Δx=70 mm) that is orientated in streamwise direction and embedded within a laterally attached flat plate. In order to separate flow noise from ocean ambient noise and other acoustical noise sources wavenumber-frequency filtering is applied. The (nondimensionalized) spectral power density of flow noise Φ(ω) ⟨U∞⟩/ (⟨δ(∗)⟩ (1/2ρ ⟨U∞⟩)(2)) is found to scale like (ω⟨δ(∗)⟩/⟨U∞⟩)(-4.3) in a wide frequency range at higher towing speeds. Here, ω, ⟨δ(∗)⟩, and ⟨U∞⟩ denote frequency, boundary layer displacement thickness, and potential flow velocity in the array region, respectively. Potential flow velocity is estimated from numerical simulations around a symmetrical, two-dimensional body with a semi-elliptical nose. Evidence is given that a χ(2)-(Tsallis) superstatistics provides a reasonable representation of the probability distribution function of flow noise at higher towing speeds. PMID:25234873

  4. Optical fiber feedback SQUID magnetometer

    SciTech Connect

    Naito, S.; Sampei, Y.; Takahashi, T. )

    1989-04-01

    This paper describes an optical fiber feedback superconducting quantum interference device (SQUID) magnetometer which was developed to improve electromagnetic interference characteristics. The SQUID consists of an RF SQUID probe, an RF amplifier, two multimode fibers, and a SQUID control unit. Phase-locked pulse width modulation (PWM) was used to construct a flux locked loop (FLL) circuit in the SQUID control unit. The operation of the optical fiber feedback SQUID is stable when a common mode voltage of ac 100 V/50 Hz is applied. It has an energy resolution of 1 x 10/sup -28/ J/Hz. This paper also describes the measurement of an auditory evoked field from the human brain in a magnetically shielded room using the fiber feedback SQUID with a gradiometer type pickup coil.

  5. Micromachined magnetoflexoelastic resonator based magnetometer

    NASA Astrophysics Data System (ADS)

    Hatipoglu, Gokhan; Tadigadapa, Srinivas

    2015-11-01

    In this paper, we demonstrate the performance of a magnetoflexoelastic magnetometer consisting of a micromachined ultra-thin (7.5 μm) quartz bulk acoustic resonator on which 500 nm thick magnetostrictive Metglas® (Fe85B5Si10) film is deposited. The resonance frequency of the unimorph resonator structure is sensitively affected by the magnetostrictively induced flexoelastic effect in quartz and is exploited to detect low frequency (<100 Hz) and nanoTesla magnetic fields. The resonance frequency shift is measured by tracking the at-resonance admittance of the resonator as a function of the applied magnetic field. The frequency shifts are linearly correlated to the magnetic field strength. A minimum detectable magnetic flux density of ˜79 nT has been measured for 10 Hz modulated magnetic field input signals which corresponds to a frequency sensitivity of 0.883 Hz/μT.

  6. 46 CFR 15.610 - Master and mate (pilot) of towing vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...: (1) To operate a towing vessel with tank barges, or a tow of barges carrying hazardous materials... without barges, or a tow of uninspected barges, an officer in charge of the towing vessel must...

  7. Advanced tow placement of composite fuselage structure

    NASA Technical Reports Server (NTRS)

    Anderson, Robert L.; Grant, Carroll G.

    1992-01-01

    The Hercules NASA ACT program was established to demonstrate and validate the low cost potential of the automated tow placement process for fabrication of aircraft primary structures. The program is currently being conducted as a cooperative program in collaboration with the Boeing ATCAS Program. The Hercules advanced tow placement process has been in development since 1982 and was developed specifically for composite aircraft structures. The second generation machine, now in operation at Hercules, is a production-ready machine that uses a low cost prepreg tow material form to produce structures with laminate properties equivalent to prepreg tape layup. Current program activities are focused on demonstration of the automated tow placement process for fabrication of subsonic transport aircraft fuselage crown quadrants. We are working with Boeing Commercial Aircraft and Douglas Aircraft during this phase of the program. The Douglas demonstration panels has co-cured skin/stringers, and the Boeing demonstration panel is an intricately bonded part with co-cured skin/stringers and co-bonded frames. Other aircraft structures that were evaluated for the automated tow placement process include engine nacelle components, fuselage pressure bulkheads, and fuselage tail cones. Because of the cylindrical shape of these structures, multiple parts can be fabricated on one two placement tool, thus reducing the cost per pound of the finished part.

  8. Aerothermodynamic Analyses of Towed Ballutes

    NASA Technical Reports Server (NTRS)

    Gnoffo, Peter A.; Buck, Greg; Moss, James N.; Nielsen, Eric; Berger, Karen; Jones, William T.; Rudavsky, Rena

    2006-01-01

    A ballute (balloon-parachute) is an inflatable, aerodynamic drag device for application to planetary entry vehicles. Two challenging aspects of aerothermal simulation of towed ballutes are considered. The first challenge, simulation of a complete system including inflatable tethers and a trailing toroidal ballute, is addressed using the unstructured-grid, Navier-Stokes solver FUN3D. Auxiliary simulations of a semi-infinite cylinder using the rarefied flow, Direct Simulation Monte Carlo solver, DSV2, provide additional insight into limiting behavior of the aerothermal environment around tethers directly exposed to the free stream. Simulations reveal pressures higher than stagnation and corresponding large heating rates on the tether as it emerges from the spacecraft base flow and passes through the spacecraft bow shock. The footprint of the tether shock on the toroidal ballute is also subject to heating amplification. Design options to accommodate or reduce these environments are discussed. The second challenge addresses time-accurate simulation to detect the onset of unsteady flow interactions as a function of geometry and Reynolds number. Video of unsteady interactions measured in the Langley Aerothermodynamic Laboratory 20-Inch Mach 6 Air Tunnel and CFD simulations using the structured grid, Navier-Stokes solver LAURA are compared for flow over a rigid spacecraft-sting-toroid system. The experimental data provides qualitative information on the amplitude and onset of unsteady motion which is captured in the numerical simulations. The presence of severe unsteady fluid - structure interactions is undesirable and numerical simulation must be able to predict the onset of such motion.

  9. Fiber-integrated diamond-based magnetometer

    NASA Astrophysics Data System (ADS)

    Liu, Xiaodi; Cui, Jinming; Sun, Fangwen; Song, Xuerui; Feng, Fupan; Wang, Junfeng; Zhu, Wei; Lou, Liren; Wang, Guanzhong

    2013-09-01

    We demonstrated a fiber-integrated diamond-based magnetometer in this paper. In the system, the fluorescence of nitrogen vacancy (NV) centers in nanodiamonds deposited on a tapered fiber was coupled to the tapered fiber effectively and detected at the output end of the fiber. By using this scheme, optically detected electron spin resonance spectra were recorded for single NV centers. The results confirmed that such a tapered fiber-nanodiamond system can act as a magnetometer. Featured with excellent portability, convenient fabrication, and potential for further integration, the constructed system has been demonstrated to be a practical magnetometer prototype.

  10. Lunar magnetic permeability studies and magnetometer sensitivity

    NASA Technical Reports Server (NTRS)

    King, J. H.; Ness, N. F.

    1977-01-01

    A regression of quiet magnetic field components simultaneously measured by the two Explorer 35 magnetometers reveals uncertainties in effective sensitivity factors of up to a few percent in one or both of these instruments. Given this, the validity of previous lunar permeability studies based on Explorer 35/ALSEP regressions, wherein inferences are drawn from regression line slopes differing from unity by the order of one percent, is called into question. We emphasize the need to critically address the question of small deviations in magnetometer sensitivity factors from nominal values as a part of any two-magnetometer lunar permeability study.

  11. 49 CFR 393.70 - Coupling devices and towing methods, except for driveaway-towaway operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... that tows it. (b) Fifth wheel assemblies—(1) Mounting—(i) Lower half. The lower half of a fifth wheel... equipped with a tow-bar and a means of attaching the tow-bar to the towing and towed vehicles. The tow-bar... strength and rigidity of the frame to prevent its undue distortion. (d) Safety devices in case of...

  12. 11. VIEW NORTH OF REAR OF TOW VEHICLE. NOTE CURRENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. VIEW NORTH OF REAR OF TOW VEHICLE. NOTE CURRENT COLLECTORS AT TOP LEFT AND OVERHEAD TROLLEY WIRES FOR POWER TRANSMISSION TO DRIVE MOTORS. - NASA Langley Research Center, Seaplane Towing Channel, 108 Andrews Street, Hampton, Hampton, VA

  13. Customized ATP towpreg. [Automated Tow Placement

    NASA Technical Reports Server (NTRS)

    Sandusky, Donald A.; Marchello, Joseph M.; Baucom, Robert M.; Johnston, Norman J.

    1992-01-01

    Automated tow placement (ATP) utilizes robotic technology to lay down adjacent polymer-matrix-impregnated carbon fiber tows on a tool surface. Consolidation and cure during ATP requires that void elimination and polymer matrix adhesion be accomplished in the short period of heating and pressure rolling that follows towpreg ribbon placement from the robot head to the tool. This study examined the key towpreg ribbon properties and dimensions which play a significant role in ATP. Analysis of the heat transfer process window indicates that adequate heating can be achieved at lay down rates as high as 1 m/sec. While heat transfer did not appear to be the limiting factor, resin flow and fiber movement into tow lap gaps could be. Accordingly, consideration was given to towpreg ribbon having uniform yet non-rectangular cross sections. Dimensional integrity of the towpreg ribbon combined with customized ribbon architecture offer great promise for processing advances in ATP of high performance composites.

  14. ATS-6 - UCLA fluxgate magnetometer

    NASA Technical Reports Server (NTRS)

    Mcpherron, R. L.; Coleman, P. J., Jr.; Snare, R. C.

    1975-01-01

    A summary of the design of the University of California at Los Angeles' fluxgate magnetometer is presented. Instrument noise in the bandwidth 0.001 to 1.0 Hz is of order 85 m gamma. The DC field of the spacecraft transverse to the earth-pointing axis is 1.0 + or - 21 gamma in the X direction and -2.4 + or - 1.3 gamma in the Y direction. The spacecraft field parallel to this axis is less than 5 gamma. The small spacecraft field has made possible studies of the macroscopic field not previously possible at synchronous orbit. At the 96 W longitude of Applications Technology Satellite-6 (ATS-6), the earth's field is typically inclined 30 deg to the dipole axis at local noon. Most perturbations of the field are due to substorms. These consist of a rotation in the meridian to a more radial field followed by a subsequent rotation back. The rotation back is normally accompanied by transient variations in the azimuthal field. The exact timing of these perturbations is a function of satellite location and the details of substorm development.

  15. The Pioneer XI high field fluxgate magnetometer

    NASA Technical Reports Server (NTRS)

    Acuna, M. A.; Ness, N. F.

    1975-01-01

    The high field fluxgate magnetometer experiment flown aboard the Pioneer XI spacecraft is described. This extremely simple instrument was used to extend the spacecraft's upper-limit measurement capability by approximately an order of magnitude (from 0.14 mT to 1.00 mT) with minimum power and volume requirements. This magnetometer was designed to complement the low-field measurements provided by a helium vector magnetometer and utilizes magnetic ring core sensors with biaxial orthogonal sense coils. The instrument is a single-range, triaxial-fluxgate magnetometer capable of measuring fields of up to 1 mT along each orthogonal axis, with a maximum resolution of 1 microT.

  16. Sensitivity of double-resonance alignment magnetometers

    SciTech Connect

    Di Domenico, Gianni; Saudan, Herve; Bison, Georg; Knowles, Paul; Weis, Antoine

    2007-08-15

    We present an experimental study of the intrinsic magnetometric sensitivity of an optical or rf-frequency double-resonance magnetometer in which linearly polarized laser light is used in the optical pumping and detection processes. We show that a semiempirical model of the magnetometer can be used to describe the magnetic resonance spectra. Then, we present an efficient method to predict the optimum operating point of the magnetometer, i.e., the light power and rf Rabi frequency providing maximum magnetometric sensitivity. Finally, we apply the method to investigate the evolution of the optimum operating point with temperature. The method is very efficient to determine relaxation rates and thus allowed us to determine the three collisional disalignment cross sections for the components of the alignment tensor. Both first and second harmonic signals from the magnetometer are considered and compared.

  17. 78 FR 60890 - Towing Safety Advisory Committee; Vacancies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-02

    ... SECURITY Coast Guard Towing Safety Advisory Committee; Vacancies AGENCY: Coast Guard. ACTION: Request for applications. SUMMARY: The Coast Guard seeks applications for membership on the Towing Safety Advisory... relating ] to shallow-draft inland and coastal waterway navigation and towing safety. Applicants...

  18. 33 CFR 86.15 - Towing vessel whistles.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Towing vessel whistles. 86.15... NAVIGATION RULES ANNEX III: TECHNICAL DETAILS OF SOUND SIGNAL APPLIANCES Whistles § 86.15 Towing vessel whistles. A power-driven vessel normally engaged in pushing ahead or towing alongside may, at all...

  19. Advanced helium magnetometer for space applications

    NASA Technical Reports Server (NTRS)

    Slocum, Robert E.

    1987-01-01

    The goal of this effort was demonstration of the concepts for an advanced helium magnetometer which meets the demands of future NASA earth orbiting, interplanetary, solar, and interstellar missions. The technical effort focused on optical pumping of helium with tunable solid state lasers. We were able to demonstrate the concept of a laser pumped helium magnetometer with improved accuracy, low power, and sensitivity of the order of 1 pT. A number of technical approaches were investigated for building a solid state laser tunable to the helium absorption line at 1083 nm. The laser selected was an Nd-doped LNA crystal pumped by a diode laser. Two laboratory versions of the lanthanum neodymium hexa-aluminate (LNA) laser were fabricated and used to conduct optical pumping experiments in helium and demonstrate laser pumped magnetometer concepts for both the low field vector mode and the scalar mode of operation. A digital resonance spectrometer was designed and built in order to evaluate the helium resonance signals and observe scalar magnetometer operation. The results indicate that the laser pumped sensor in the VHM mode is 45 times more sensitive than a lamp pumped sensor for identical system noise levels. A study was made of typical laser pumped resonance signals in the conventional magnetic resonance mode. The laser pumped sensor was operated as a scalar magnetometer, and it is concluded that magnetometers with 1 pT sensitivity can be achieved with the use of laser pumping and stable laser pump sources.

  20. X-34 and HSTV tow vehicle on lakebed prior to tow test

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Following initial captive flight tests last year at NASA's Dryden Flight Research Center, Edwards Air Force Base, California, the X-34 technology demonstrator began a new series of tests last week in which it is being towed behind a semi-truck and released to coast on the Edwards dry lakebed. On July 20, 2000, it was towed and released twice at speeds of five and 10 miles per hour. On July 24, 2000, it was towed and released twice at 10 and 30 miles per hour. Twelve tests are planned during which the X-34 will be towed for distances up to 10,000 feet and released at speeds up to 80 miles per hour. The test series is expected to last at least six weeks.

  1. Development of marine magnetic vector measurement system using AUV and deep-towed vehicle

    NASA Astrophysics Data System (ADS)

    Sayanagi, K.; Isezaki, N.; Matsuo, J.; Harada, M.; Kasaya, T.; Nishimura, K.; Baba, H.

    2012-04-01

    Marine magnetic survey is one of useful methods in order to investigate the nature of the oceanic crust. Most of the data are, however, intensity of the geomagnetic field without its direction. Therefore we cannot properly apply a physical formula describing the relation between magnetic field and magnetization to analyses of the data. With this problem, Isezaki (1986) developed a shipboard three-component magnetometer which measures the geomagnetic vector at the sea. On the other hand, geophysical surveys near the seafloor have been more and more necessary in order to show the details of the oceanic crust. For instance, development of seabed resources like hydrothermal deposits needs higher resolution surveys compared with conventional surveys at the sea for accurate estimation of abundance of the resources. From these viewpoints, we have been developing a measurement system of the deep-sea geomagnetic vector using AUV and deep-towed vehicle. The measurement system consists of two 3-axis flux-gate magnetometers, an Overhauser magnetometer, an optical fiber gyro, a main unit (control, communication, recording), and an onboard unit. These devices except for the onboard unit are installed in pressure cases (depth limit: 6000m). Thus this measurement system can measure three components and intensity of the geomagnetic field in the deep-sea. In 2009, the first test of the measurement system was carried out in the Kumano Basin using AUV Urashima and towing vehicle Yokosuka Deep-Tow during the R/V Yokosuka YK09-09 cruise. In this test, we sank a small magnetic target to the seafloor, and examined how the system worked. As a result, we successfully detected magnetic anomaly of the target to confirm the expected performance of that in the sea. In 2010, the measurement system was tested in the Bayonnaise Knoll area both using a titanium towing frame during the R/V Bosei-maru cruise and using AUV Urashima during the R/V Yokosuka YK10-17 cruise. The purpose of these tests was

  2. The Chromosphere and Prominence Magnetometer

    NASA Astrophysics Data System (ADS)

    de Wijn, Alfred; Bethge, Christian; McIntosh, Scott; Tomczyk, Steven; Burkepile, Joan

    2013-04-01

    The Chromosphere and Prominence Magnetometer (ChroMag) is a synoptic instrument with the goal of quantifying the intertwined dynamics and magnetism of the solar chromosphere and in prominences through imaging spectro-polarimetry of the full solar disk in a synoptic fashion. The picture of chromospheric magnetism and dynamics is rapidly developing, and a pressing need exists for breakthrough observations of chromospheric vector magnetic field measurements at the true lower boundary of the heliospheric system. ChroMag will provide measurements that will enable scientists to study and better understand the energetics of the solar atmosphere, how prominences are formed, how energy is stored in the magnetic field structure of the atmosphere and how it is released during space weather events like flares and coronal mass ejections. An essential part of the ChroMag program is a commitment to develop and provide community access to the `inversion' tools necessary to interpret the measurements and derive the magneto-hydrodynamic parameters of the plasma. Measurements of an instrument like ChroMag provide critical physical context for the Solar Dynamics Observatory (SDO) and Interface Region Imaging Spectrograph (IRIS) as well as ground-based observatories such as the future Advanced Technology Solar Telescope (ATST). A prototype is currently under construction at the High Altitude Observatory of the National Center for Atmospheric Research in Boulder, CO, USA. The heart of the ChroMag instrument is an electro-optically tunable wide-fielded narrow-band birefringent six-stage Lyot filter with a built-in polarimeter. We will present a progress update on the ChroMag design, and present results from the prototype instrument.

  3. SEADYN Analysis of a Tow Line for a High Altitude Towed Glider

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.

    1996-01-01

    The concept of using a system, consisting of a tow aircraft, glider and tow line, which would enable subsonic flight at altitudes above 24 km (78 kft) has previously been investigated. The preliminary results from these studies seem encouraging. Under certain conditions these studies indicate the concept is feasible. However, the previous studies did not accurately take into account the forces acting on the tow line. Therefore in order to investigate the concept further a more detailed analysis was needed. The code that was selected was the SEADYN cable dynamics computer program which was developed at the Naval Facilities Engineering Service Center. The program is a finite element based structural analysis code that was developed over a period of 10 years. The results have been validated by the Navy in both laboratory and at actual sea conditions. This code was used to simulate arbitrarily-configured cable structures subjected to excitations encountered in real-world operations. The Navy's interest was mainly for modeling underwater tow lines, however the code is also usable for tow lines in air when the change in fluid properties is taken into account. For underwater applications the fluid properties are basically constant over the length of the tow line. For the tow aircraft/glider application the change in fluid properties is considerable along the length of the tow line. Therefore the code had to be modified in order to take into account the variation in atmospheric properties that would be encountered in this application. This modification consisted of adding a variable density to the fluid based on the altitude of the node being calculated. This change in the way the code handled the fluid density had no effect on the method of calculation or any other factor related to the codes validation.

  4. 78 FR 49543 - Towing Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-14

    ... regarding our public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). Docket... Discharges Incidental to the Normal Operation of a Vessel-- NPDES Vessel General Permit (VGP) (78 FR 21938... SECURITY Coast Guard Towing Safety Advisory Committee AGENCY: Coast Guard, DHS. ACTION:...

  5. Towed Articulated Housing For Geophysical Measurements

    NASA Technical Reports Server (NTRS)

    Burke, James D.; Cantrell, James

    1992-01-01

    Snakelike articulated string of rigid shells towed by helicopter, boat, kite or balloon, carries scientific instruments over land and sea surfaces. Nested shells connected to internal chain by bolt covered by preceding cone. String articulates readily to negotiate obstacles, but locally stiff to lie across a narrow crevasse.

  6. 76 FR 49975 - Inspection of Towing Vessels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-11

    ... notice regarding our public dockets in the January 17, 2008 issue of the Federal Register (73 FR 3316). D... Administration FR Federal Register FRA Federal Railroad Administration GAO Government Accountability Office gpm... public meetings titled ``Inspection of Towing Vessels'' in the Federal Register (69 FR 78471). The...

  7. Simplified method of deep-tow seismic profiling

    USGS Publications Warehouse

    Robb, James M.; Sylwester, Richard E.; Penton, Ronald

    1981-01-01

    To improve resolution of seismic-reflection profiles in continental slope water depths of 900 to 1500 m, a single hydrophone was towed about 150 m off the bottom to receive reflected signals from a surface-towed sparker sound source. That deep-towed hydrophone data show that valleys which appear V-shaped in records from a surface-towed hydrophone are flat-bottomed, and that subbottom reflections from an erosional unconformity can be much better resolved. The data produced by this technique are very hepful when used in conjunction with records from conventional surface-towed seismic-profiling equipment.

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

    NASA Technical Reports Server (NTRS)

    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.

  9. The Magnetometer Instrument on MESSENGER

    NASA Astrophysics Data System (ADS)

    Anderson, Brian J.; Acuña, Mario H.; Lohr, David A.; Scheifele, John; Raval, Asseem; Korth, Haje; Slavin, James A.

    2007-08-01

    The Magnetometer (MAG) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission is a low-noise, tri-axial, fluxgate instrument with its sensor mounted on a 3.6-m-long boom. The boom was deployed on March 8, 2005. The primary MAG science objectives are to determine the structure of Mercury’s intrinsic magnetic field and infer its origin. Mariner 10 observations indicate a planetary moment in the range 170 to 350 nT R {M/3} (where R M is Mercury’s mean radius). The uncertainties in the dipole moment are associated with the Mariner 10 trajectory and variability of the measured field. By orbiting Mercury, MESSENGER will significantly improve the determination of dipole and higher-order moments. The latter are essential to understanding the thermal history of the planet. MAG has a coarse range, ±51,300 nT full scale (1.6-nT resolution), for pre-flight testing, and a fine range, ±1,530 nT full scale (0.047-nT resolution), for Mercury operation. A magnetic cleanliness program was followed to minimize variable and static spacecraft-generated fields at the sensor. Observations during and after boom deployment indicate that the fixed residual field is less than a few nT at the location of the sensor, and initial observations indicate that the variable field is below 0.05 nT at least above about 3 Hz. Analog signals from the three axes are low-pass filtered (10-Hz cutoff) and sampled simultaneously by three 20-bit analog-to-digital converters every 50 ms. To accommodate variable telemetry rates, MAG provides 11 output rates from 0.01 s-1 to 20 s-1. Continuous measurement of fluctuations is provided with a digital 1-10 Hz bandpass filter. This fluctuation level is used to trigger high-time-resolution sampling in eight-minute segments to record events of interest when continuous high-rate sampling is not possible. The MAG instrument will provide accurate characterization of the intrinsic planetary field, magnetospheric structure, and

  10. Automatic magnetometer calibration with small space coverage

    NASA Astrophysics Data System (ADS)

    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

  11. The AUTUMNX magnetometer meridian chain in Québec, Canada

    NASA Astrophysics Data System (ADS)

    Connors, Martin; Schofield, Ian; Reiter, Kyle; Chi, Peter J.; Rowe, Kathryn M.; Russell, Christopher T.

    2016-01-01

    The AUTUMNX magnetometer array consists of 10 THEMIS-class ground-based magnetometers deployed to form a meridian chain on the eastern coast of Hudson Bay in eastern Canada, a second partial chain one hour of magnetic local time further east, and one magnetometer at an intermediate midlatitude site. These instruments, augmented by those of other arrays, permit good latitudinal coverage through the auroral zone on two meridians, some midlatitude coverage, and detection of magnetic field changes near the sensitive infrastructure of the Hydro-Québec power grid. Further, they offer the possibility for conjugate studies with Antarctica and the GOES East geosynchronous satellite, and complement the Chinese International Space Weather Meridian Circle Program. We examine current world distribution of magnetometers to show the need for AUTUMNX, and describe the instrumentation which allows near-real-time monitoring. We present magnetic inversion results for the disturbed day February 17, 2015, which showed classic signatures of the substorm current wedge, and developed into steady magnetospheric convection (SMC). For a separate event later that day, we examine a large and rapid magnetic field change event associated with an unusual near-Earth transient. We show GOES East conjugacy for these events.

  12. Magnetic induction imaging with optical atomic magnetometers: towards applications to screening and surveillance

    NASA Astrophysics Data System (ADS)

    Marmugi, Luca; Hussain, Sarah; Deans, Cameron; Renzoni, Ferruccio

    2015-10-01

    We propose a new approach, based on optical atomic magnetometers and magnetic induction tomography (MIT), for remote and non-invasive detection of conductive targets. Atomic magnetometers overcome the main limitations of conventional MIT instrumentation, in particular their poor low-frequency sensitivity, their large size and their limited scalability. Moreover, atomic magnetometers have been proven to reach extremely high sensitivities, with an improvement of up to 7 orders of magnitude in the 50 MHz to DC band, with respect to a standard pick-up coil of the same size. In the present scheme, an oscillating magnetic field induces eddy currents in a conductive target and laser-pumped atomic magnetometers, either stand-alone or in an array, detect the response of the objects. A phase-sensitive detection scheme rejects the background, allowing remote detection of the secondary field and, thus, mapping of objects, hidden in cargos, underwater or underground. The potential for extreme sensitivity, miniaturization, dynamic range and array operation paves the way to a new generation of non-invasive, active detectors for surveillance, as well as for real-time cargo screening.

  13. MAGDAS I and II Magnetometers in Peru

    NASA Astrophysics Data System (ADS)

    Choque, Ed.; Ishitsuka, J.; Yumoto, K.; Veliz, O.; Rosales, D.

    2014-01-01

    The Department of Terrestrial Magnetism of the Car negie Institution of Washington founded in 1919 the Huancayo Observatory, in Peru (Lat. -12.060, Long - 75.210) and installed a classical magnetometer which has provided a long standing flow of data since March 1st, 1922. Today, there are 10 magnetometers in operation in Peru. On October 13th, 2006, Space Environment Research Center - SERC of Kyushu University installed a new Magnetic Dat a Acquisition System MAGDAS I (PI; Prof. K. Yumoto) at Ancon Observatory (Geographic Latitude: -11.790, Longitude: - 77.160 and Geomagnetic Latitude (2000): 3.100 and Longitude (2000): 354.660). On July 13th, 2011, SERC installed a MAGDAS II at Ica Solar Station (Geographic Latitude: - 140 04' Longitude: -750 44'). Details of the magnetometer that we are hosting will be explained in this presentation.

  14. Swarm's Absolute Scalar Magnetometer metrological performances

    NASA Astrophysics Data System (ADS)

    Leger, J.; Fratter, I.; Bertrand, F.; Jager, T.; Morales, S.

    2012-12-01

    The Absolute Scalar Magnetometer (ASM) has been developed for the ESA Earth Observation Swarm mission, planned for launch in November 2012. As its Overhauser magnetometers forerunners flown on Oersted and Champ satellites, it will deliver high resolution scalar measurements for the in-flight calibration of the Vector Field Magnetometer manufactured by the Danish Technical University. Latest results of the ground tests carried out to fully characterize all parameters that may affect its accuracy, both at instrument and satellite level, will be presented. In addition to its baseline function, the ASM can be operated either at a much higher sampling rate (burst mode at 250 Hz) or in a dual mode where it also delivers vector field measurements as a by-product. The calibration procedure and the relevant vector performances will be discussed.

  15. MULTI-SENSOR TOWED ARRAY DETECTION SYSTEM (MTADS)

    EPA Science Inventory

    UXO is a serious and prevalent environmental problem currently facing DoD facility managers. Mitigation and remediation activities are often hindered by the fact that UXO is colocated with other environmental threats including ordnance explosives wastes (OEW), chemical wastes, an...

  16. Low-cost dipole hydrophone for use in towed arrays

    SciTech Connect

    Abraham, B.M.

    1996-04-01

    The design, fabrication, and testing of a low-cost acoustic particle velocity sensor are described. The primary design parameters for the dipole hydrophone are low-cost, low-mass, and small size. The sensor uses commercially available geophones to locally measure one or more components of the acoustic particle velocity field. The geophones are encapsulated in a syntactic foam to reduce their average density and hence increase their acoustic sensitivity. This method of fabrication greatly reduces costs compared to conventional methods which use machined cases. The on-axis voltage sensitivity was measured experimentally using two methods. The first used a uniaxial vibration shaker to estimate the intrinsic velocity sensitivity of the encapsulated geophone with the case fixed to the shaker head. The second measured the {ital in} {ital situ} acoustic sensitivity in water. Theoretical models of the voltage sensitivity for these two cases are developed and the results compare very well with the experimental data. Additionally, rotator tests were performed at frequencies of 100, 500, 600, and 1000 Hz to measure the quality of the dipole directivity pattern in water. Near-theoretical dipole patterns, with nulls better than 30 dB, were measured. {copyright} {ital 1996 American Institute of Physics.}

  17. Parametric modulation of an atomic magnetometer

    PubMed Central

    Li, Zhimin; Wakai, Ronald T.; Walker, Thad G.

    2012-01-01

    The authors report on a rubidium atomic magnetometer designed for use in a shielded environment. Operating in the spin-exchange relaxation-free regime, the magnetometer utilizes parametric modulation of the z-magnetic field to suppress noise associated with airflow through the oven and to simultaneously detect x- and y-field components, using a single probe beam, with minimal loss of sensitivity and bandwidth. A white noise level of 60 fT/(Hz)1/2 was achieved. PMID:22942436

  18. Cassini magnetometer measurements in the Jovian environment

    NASA Astrophysics Data System (ADS)

    Dougherty, M. K.

    2001-05-01

    M. K. Dougherty, and the Cassini magnetometer team The recent Cassini flyby of Jupiter had the spacecraft flying along the dusk flank of the magnetosphere, a region which has only been visited very briefly before during the Ulysses outbound pass. The unique Cassini flyby resulted in the spacecraft making numerous entries into the magnetosheath region as well as into the magnetosphere itself. Initial results from the magnetometer instrument will be described including information concerning the solar wind IMF, the large amount of mirror mode activity measured within the magnetosheath and incursions into the magnetosphere proper.

  19. Magnetometer deployment mechanism for Pioneer Venus

    NASA Technical Reports Server (NTRS)

    Townsend, W. L.

    1977-01-01

    A three segment, 15-foot boom mechanism was developed to deploy magnetometers from the Pioneer Venus orbiter spinning shelf. The stowage mechanism is designed to contain the magnetometers during launch and to deploy these instruments by centrifugal force upon pyrotechnic release. Unique graphite-epoxy boom segments are used for a lightweight design with sufficient strength to withstand a 7.5 g orbit insertion force while extended. The detailed design is described along with the test methods developed for qualification in a one-g field.

  20. Magnetometer deployment mechanism for Pioneer Venus

    NASA Technical Reports Server (NTRS)

    Townsend, W. L.

    1977-01-01

    A three segment, 15-foot boom mechanism was developed to deploy magnetometers from the Pioneer Venus orbiter spinning shelf. The stowage mechanism is designed to contain the magnetometers during launch and to deploy these instruments by centrifugal force upon pyrotechnic release. Unique graphite-epoxy boom segments are used for a lightweight design with sufficient strength to withstand a 7.5 g orbit insertion force while extended. The detailed design is described, along with the test methods developed for qualification in a one-g field.

  1. Digital flux-gate magnetometer structural analysis

    NASA Astrophysics Data System (ADS)

    Korepanov, Valery; Berkman, Rikhard

    1999-08-01

    Analogue and digital structures of the flux-gate magnetometer are compared. The main disturbing factors in digital circuit were singled out and the additional errors associated with the digital structure are estimated. The reader's attention is drawn to some specific problems associated with digital circuits - the special influence of the unbalanced voltage amplitude at the flux-gate-sensor output and ADC-DAC switching-time instabilities. The given analytical results could be useful for the designer when it is necessary to make a choice of the structural type of magnetometer.

  2. Aircraft attitude measurement using a vector magnetometer

    NASA Technical Reports Server (NTRS)

    Peitila, R.; Dunn, W. R., Jr.

    1977-01-01

    The feasibility of a vector magnetometer system was investigated by developing a technique to determine attitude given magnetic field components. Sample calculations are then made using the earth's magnetic field data acquired during actual flight conditions. Results of these calculations are compared graphically with measured attitude data acquired simultaneously with the magnetic data. The role and possible implementation of various reference angles are discussed along with other pertinent considerations. Finally, it is concluded that the earth's magnetic field as measured by modern vector magnetometers can play a significant role in attitude control systems.

  3. Design and simulation of MEMS capacitive magnetometer

    NASA Astrophysics Data System (ADS)

    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.

  4. Vector magnetometer as an attitude determining instrument

    NASA Technical Reports Server (NTRS)

    Pietila, R.; Dunn, W. R., Jr.

    1974-01-01

    The solid state vector magnetometer sensor system is presented for the accuracy and reliability of existing systems, and for providing independent measures of attitude. Since a large number of aircraft heading reference systems depend on measurement of the earth's magnetic field, it can be shown that by substituting a 3-axis magnetometer for the remote sensing unit, both heading and attitude measurement functions can be derived using common elements. Sample calculations are made using the earth's magnetic field data acquired during actual flight conditions.

  5. Parametric modulation of an atomic magnetometer.

    PubMed

    Li, Zhimin; Wakai, Ronald T; Walker, Thad G

    2006-01-01

    The authors report on a rubidium atomic magnetometer designed for use in a shielded environment. Operating in the spin-exchange relaxation-free regime, the magnetometer utilizes parametric modulation of the z-magnetic field to suppress noise associated with airflow through the oven and to simultaneously detect x- and y-field components, using a single probe beam, with minimal loss of sensitivity and bandwidth. A white noise level of 60 fT/(Hz)(1/2) was achieved. PMID:22942436

  6. Deep-tow geophysical survey above large exhumed mantle domains of the eastern Southwest Indian ridge

    NASA Astrophysics Data System (ADS)

    Bronner, A.; Munschy, M.; Sauter, D.; Carlut, J.; Searle, R.; Cannat, M.

    2012-04-01

    The recent discovery of a new type of seafloor, the "smooth seafloor", formed with no or very little volcanic activity along the easternmost part of the ultra-slow spreading Southwest Indian ridge (SWIR) shows an unexpected complexity in processes of generation of the oceanic lithosphere. There, detachment faulting is thought to be a mechanism for efficient exhumation of deep-seated mantle rocks. We present here a deep-tow geological-geophysical survey over smooth seafloor at the eastern SWIR (62-64°N) combining multibeam bathymetric data, magnetic data, geology mapping from sidescan sonar (TOBI) images and results from dredge sampling. We introduce a new type of calibration approach for deep-tow fluxgate magnetometer. We show that magnetic data can be corrected from the magnetic effect of the vehicle with no recourse to its attitude (pitch, roll and heading) but only using the 3 components recorded by the magnetometer and an approximation of the scalar intensity of the Earth magnetic field. The collected dredge samples as well as the sidescan sonar images confirm the presence of large areas of exhumed mantle-derived peridodites surrounded by a few volcanic constructions. We investigate the possibility that magnetic anomalies are either caused by serpentinized peridotites and/or magmatic intrusions. We show that the magnetic signature of the smooth seafloor is clearly weaker than the surrounding volcanic areas. Moreover, the calculated magnetization of a source layer as well as the comparison between deep-tow and sea-surface magnetic data argue for strong East-West variability in the distribution of the magnetized sources. This variability may result from fluid-rock interactions along the detachment faults as well as from the occurrence of small sized and thin volcanic patches and thus questions the seafloor spreading origin of the corresponding magnetic anomalies. Finally, we provide magnetic arguments, as calculation of block rotation or spreading asymmetry in

  7. Microsatellite Digital Magnetometer SMILE - Present State and Future Trends

    NASA Astrophysics Data System (ADS)

    Belyayev, Serhiy; Ivchenko, Nickolay

    2010-05-01

    The fluxgate magnetometers (FGM) are probably the most widespread instruments used onboard spacecrafts for both scientific and service purposes. The recent trend to decrease the weight and size of the spacecrafts requires creating as small as possible but enough sensitive FGM. A joint Swedish-Ukrainian team made the development of such a magnetometer and as the result the Small Magnetometer In Low mass Experiment (SMILE) - a digital fluxgate microsatellite magnetometer - was created [1]. Majority of electronic units of this FGM were combined in a digital integrated circuit - a Field Programmable Gate Array (FPGA). The FPGA provides full processing (determined by a digital correlation algorithm) of amplified and digitized fluxgate sensor output signals and provides both FGM output data and feedback signals. Such digital design makes the instrument very flexible, reduces power consumption and opens possibilities for customization of the operation modes. It allows miniaturizing the electronic unit and, together with the smallest in the world low noise three-component fluxgate sensor with the side dimension of 20 mm and weight about 20 grams only, the small but enough sensitive space qualified FGM is created. SMILE magnetometer was successfully flown onboard the NASA Cascades-2 sounding rocket, and is to fly in the LAPLander package onboard the ESA REXUS-8 student sounding rocket [2]. Unfortunately, such a design of electronic circuit does not allow us to realize all possibilities of the miniature sensor. The separate tests of the sensor with highest-class analog electronics showed that its noise level may be reduced to as low value as 10…15 picoTesla at 1 Hz. Also the use of volume compensation in the sensor provides high geometrical stability of the axes and improved performance compared to component compensated sensors. The measured parameters appear to be comparable or even better than these of best stationary FGM and, if realized in small enough volume and

  8. Paresev 1 in Flight on Tow

    NASA Technical Reports Server (NTRS)

    1962-01-01

    Pilot with Paresev 1 (Paraglider Research Vehicle) on tow in 1962. A normal flight was a takeoff on the dry lakebed at Edwards Air Force Base and a circling flight path skirting the lake edges to insure a landing on the lakebed in the event of a towline failure. Release altitude was normally 10,000 to 13,000 feet. Data was obtained on the glide part of the flight.

  9. M2-F1 in Tow

    NASA Technical Reports Server (NTRS)

    1964-01-01

    The M2-F1 lifting body is seen here being towed behind a C-47 at the Flight Research Center (later redesignated the Dryden Flight Research Center), Edwards, California. The wingless, lifting body aircraft design was initially conceived as a means of landing an aircraft horizontally after atmospheric re-entry. The absence of wings would make the extreme heat of re-entry less damaging to the vehicle.

  10. M2-F1 In Tow Flight

    NASA Technical Reports Server (NTRS)

    1964-01-01

    The M2-F1 lifting body is seen here under tow at the Flight Research Center (later redesignated the Dryden Flight Research Center), Edwards, California. The wingless, lifting body aircraft design was initially conceived as a means of landing an aircraft horizontally after atmospheric reentry. The absence of wings would make the extreme heat of re-entry less damaging to the vehicle. In 1962, Dryden management approved a program to build a lightweight, unpowered lifting body as a prototype to flight test the wingless concept. It would look like a 'flying bathtub,' and was designated the M2-F1, the 'M' referring to 'manned' and 'F' referring to 'flight' version. It featured a plywood shell placed over a tubular steel frame crafted at Dryden. Construction was completed in 1963. The first flight tests of the M2-F1 were over Rogers Dry Lake at the end of a tow rope attached to a hopped-up Pontiac convertible driven at speeds up to about 120 mph. These initial tests produced enough flight data about the M2-F1 to proceed with flights behind a NASA C-47 tow plane at greater altitudes. The C-47 took the craft to an altitude of 12,000 feet where free flights back to Rogers Dry Lake began.

  11. Magnetometer networks during the International Magnetosphere Study

    NASA Technical Reports Server (NTRS)

    Lanzerotti, L. J.; Regan, R. D.; Sugiura, M.; Williams, D. J.

    1976-01-01

    The paper describes the geographical layout of the planned North American IMS magnetometer network and outlines some plans regarding instrumentation and data transmission services. The network consists of three meridional high-latitude chains, an east-west chain along the auroral zone, and a network of stations at mid-latitudes. In addition, the Air Force Cambridge Research Laboratories will have their own network with an east-west chain along geomagnetic latitude 54 N and some other mid-latitude stations. The preliminary magnetometer specifications require that the three-component flux gate magnetometer be accurate to within 0.25 gamma and that each axis be sampled every 10 sec. A block diagram is presented showing the proposed magnetometer station, of which the most complex piece of equipment will be the interface controller. The SMS-GOES satellite telemetry relay capability will be used for transmission of data from a selected network of magnetic stations to the Space Environment Laboratory in Boulder.

  12. The DE magnetometer preprocessor users guide

    NASA Technical Reports Server (NTRS)

    Salter, L. M.; Byrnes, J. B.

    1982-01-01

    A users guide for the Dynamics Explorer magnetometer preprocessor computer program is provided. This program is written in Xerox Extended FORTRAN IV and is used to process telemetry data in order to provide data files for use in analysis programs. This preprocessor is designed to operate on the Sigma 9 and the IBM 4341.

  13. Diffusive suppression of AC-Stark shifts in atomic magnetometers

    PubMed Central

    Sulai, I. A.; Wyllie, R.; Kauer, M.; Smetana, G. S.; Wakai, R. T.; Walker, T. G.

    2016-01-01

    In atomic magnetometers, the vector AC-Stark shift associated with circularly polarized light generates spatially varying effective magnetic fields, which limit the magnetometer response and serve as sources of noise. We describe a scheme whereby optically pumping a small subvolume of the magnetometer cell and relying on diffusion to transport polarized atoms allows a magnetometer to be operated with minimal sensitivity to the AC-Stark field. © 2013 Optical Society of America PMID:23503278

  14. Investigations and Tests in the Towing Basin at Guidonia

    NASA Technical Reports Server (NTRS)

    Cremona, C

    1939-01-01

    The experimental methods at the Guidonia towing basin are discussed including specifications. Some of the components examined are the bridge towing carriage, side towing carriage, catapult installation, and dynamometer systems. Tests were performed on hulls and floats, as well as motor boats and torpedo shaped bodies. Theoretical investigations were also performed to determine pressure distributions on geometrically simple bodies, propagation of small wave motions, and planing and submerged surfaces.

  15. 33 CFR 83.24 - Towing and pushing (Rule 24).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Towing and pushing (Rule 24). 83.24 Section 83.24 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INLAND NAVIGATION RULES RULES Lights and Shapes § 83.24 Towing and pushing (Rule 24). (a) A power-driven vessel when towing astern. A power-driven...

  16. 33 CFR 83.24 - Towing and pushing (Rule 24).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Towing and pushing (Rule 24). 83.24 Section 83.24 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INLAND NAVIGATION RULES RULES Lights and Shapes § 83.24 Towing and pushing (Rule 24). (a) A power-driven vessel when towing astern. A power-driven...

  17. Magnetic Gradiometer and Vector Magnetometer Survey of the Galapagos Triple Junction

    NASA Astrophysics Data System (ADS)

    Gee, J.; Cande, S. C.; Parker, R. L.; Lonsdale, P. F.; Bowles, J.

    2004-05-01

    Several fundamental tectonic problems of the equatorial Pacific remain unsolved due to the lack of magnetic anomaly data. A basic limitation encountered with the use of the standard proton precession magnetometer (or any total field instrument) is that total field anomalies over approximately N/S striking bodies are very small at low magnetic latitudes. Another problem encountered with magnetic surveys near the magnetic equator are the diurnal variations associated with the external field. Measurements of the vector anomalous field and total field gradient offer ways to overcome these limitations. Total field gradiometer data allow recognition and removal of time dependent external field variations. Vector magnetic anomalies provide two distinct advantages over total field measurements. Although the total field anomalies are small (typically 50 nT) over most of the equatorial Pacific, the vertical and horizontal components of the anomalous field are 2-5 times larger. In addition, vector anomaly data can be used to evaluate the two dimensionality of the magnetic source since the along track and vertical anomalies are related by a 90o phase shift for a perfectly two dimensional source. To evaluate the advantages of these systems, we conducted a survey of the trails of the Galapagos triple junction using both a high resolution total field gradiometer and a vector magnetometer. The longitudinal gradiometer system consists of two Overhauser sensors (0.01 nT sensitivity) towed 350 and 450m behind the survey vessel. The towed vector magnetometer utilizes a commercial motion reference sensor (0.02o orientation accuracy with three fluxgate sensors) suitable for measuring horizontal and vertical anomalies as small as 30-50 nT. Vector anomalies across Cocos-Nazca crust corroborate the high degree of linearity of these E/W lineations; horizontal and vertical anomalies exhibit high coherence (>0.9) and the expected 90o phase relationship at wavelengths longer than ~8km. Vector

  18. Method of performing MRI with an atomic magnetometer

    SciTech Connect

    Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich

    2013-08-27

    A method and apparatus are provided for performing an in-situ magnetic resonance imaging of an object. The method includes the steps of providing an atomic magnetometer, coupling a magnetic field generated by magnetically resonating samples of the object through a flux transformer to the atomic magnetometer and measuring a magnetic resonance of the atomic magnetometer.

  19. Method of performing MRI with an atomic magnetometer

    DOEpatents

    Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A.; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich

    2012-11-06

    A method and apparatus are provided for performing an in-situ magnetic resonance imaging of an object. The method includes the steps of providing an atomic magnetometer, coupling a magnetic field generated by magnetically resonating samples of the object through a flux transformer to the atomic magnetometer and measuring a magnetic resonance of the atomic magnetometer.

  20. Effects of interparticle dipole interaction on permalloy thin film arrays

    NASA Astrophysics Data System (ADS)

    Lai, Jun-Yang; Lai, Mei-Feng; Chang, Ching-Ray; Wei, Zung-Hang; Wu, J. C.; Lo, I. C.; Kuo, J. H.; Chang, Y. C.; Hsu, Jen-Hwa; Huang, Jia-Rui

    2005-05-01

    The magnetic structures and hysteresis loops of permalloy thin film arrays are investigated here using magnetic force microscopy and vibrating sample magnetometer. The strength of interparticle dipole interaction can be revealed by the number of single-domain pairs with antiparallel magnetizations when the array is relaxed from a strong hard-axis field. Besides, hysteresis loops obtained by vibrating sample magnetometer measurements show that arrays with narrower interparticle spacings have lower coercivities and remanences. The results obtained from vibrating sample magnetometer are in very good agreement with magnetic force microscopy imaging.

  1. Towed Twin-Fuselage Glider Launch System (CGI Animation Version 2)

    NASA Video Gallery

    The towed glider is an element of the novel rocket-launching concept of the Towed Glider Air-Launch System (TGALS). The TGALS demonstration’s goal is to provide proof-of-concept of a towed, airborn...

  2. A plateau in the sensitivity of a compact optically pumped atomic magnetometer

    SciTech Connect

    Mizutani, Natsuhiko Okano, Kazuhisa; Ban, Kazuhiro; Ichihara, Sunao; Terao, Akira; Kobayashi, Tetsuo

    2014-05-15

    In a compact optically pumped atomic magnetometer (OPAM), there is a plateau in the sensitivity where the dependence of the sensitivity on pumping power is small compared with that predicted by the uniform polarization model. The mechanism that generates this plateau was explained by numerical analysis. The distribution of spin polarization in the alkali metal cell of an OPAM was modeled using the Bloch equation incorporating a diffusion term and an equation for the attenuation of the pump beam. The model was well-fitted to the experimental results for a module with a cubic cell with 20 mm sides and pump and probe beams with 8 mm diameter. On the plateau, strong magnetic response was generated at the regions that were not illuminated directly by the intense pump beam, while at the same time spin polarization as large as 0.5 was maintained due to diffusion of the spin-polarized atoms. Thus, the sensitivity of the magnetometer monitored with a probe beam decreases only slightly with increasing pump beam intensity because the spin polarization under an intense pump beam is saturated. This plateau, which is characteristic of this type of magnetometer using a narrow pump and probe beams, can be used in arrays of magnetometers because it enables stable operation with little sensitivity fluctuation from changes in pump beam power.

  3. Super-light Magnetometers For Nanosatellites

    NASA Astrophysics Data System (ADS)

    Berkman, R.; Korepanov, V.; Marussenkov, A.; Sukhynyuk, A.

    The modern tendency to decrease the weight and dimensions of the space vehicles, especially for scientific research, imply corresponding requirements to the scientific payload too. A correlation between metrological parameters (particularly sensitivity and own noise level) and mass, dimensions and power consumption of search-coil (SC) and flux gate (FG) magnetometers was studied. In this abstract both these prob- lems are considered. In order to decrease the SC weight it appeared to be necessary to derive the common equations, which describe minimum mass criterion for search- coil sensors in different frequency bands. The corresponding algorithm, based upon "generalized" SC parameters was introduced and a set of stable combinations, rela- tively independent on dimensions, number of turns and intended frequency band was developed. It was also revealed that the preamplifier connected to SC has to be charac- terized by extended set of 8 known noise parameters. As a result, the new approach of calculation and design of minimum-weight of SC magnetometers was proposed. All that allowed to manufacture first model of space qualified SC magnetometers with the following parameters: weight - 75 g, noise level density - 2 fT/sqrt(Hz) at 50 kHz. The most important problem for super-light FG magnetometers creation with low power consumption is to reduce the FG sensor (FGS) excitation power. Based on earlier de- veloped ferroresonance excitation mode a new study in this direction was made. The relations allowing to estimate the minimally possible FGS excitation power were de- rived, which allow for the given FGS dimensions and given mumetal saturation level to determine the required power. It was obtained that if we diminish the FGS volume in n^3 times, the possible power drop is only n times. Using new methodology a set of super-light FG magnetometers was manufactured with the sensor about 12 x 5 x 5 mm, consumed power about 2 mW and noise level density about 100 pT/sqrt(Hz) at

  4. Aerodynamics modeling of towed-cable dynamics

    SciTech Connect

    Kang, S.W.; Latorre, V.R.

    1991-01-17

    The dynamics of a cable/drogue system being towed by an orbiting aircraft has been investigated as a part of an LTWA project for the Naval Air Systems Command. We present here a status report on the tasks performed under Phase 1. We have accomplished the following tasks under Phase 1: A literature survey on the towed-cable motion problem has been conducted. While both static (steady-state) and dynamic (transient) analyses exist in the literature, no single, comprehensive analysis exists that directly addresses the present problem. However, the survey also reveals that, when judiciously applied, these past analyses can serve as useful building blocks for approaching the present problem. A numerical model that addresses several aspects of the towed-cable dynamic problem has been adapted from a Canadian underwater code for the present aerodynamic situation. This modified code, called TOWDYN, analyzes the effects of gravity, tension, aerodynamic drag, and wind. Preliminary results from this code demonstrate that the wind effects alone CAN generate the drogue oscillation behavior, i.e., the yo-yo'' phenomenon. This code also will serve as a benchmark code for checking the accuracy of a more general and complete R D'' model code. We have initiated efforts to develop a general R D model supercomputer code that also takes into account other physical factors, such as induced oscillations and bending stiffness. This general code will be able to evaluate the relative impacts of the various physical parameters, which may become important under certain conditions. This R D code will also enable development of a simpler operational code that can be used by the Naval Air personnel in the field.

  5. 78 FR 20684 - Towing Safety Advisory Committee; Vacancies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-05

    ... SECURITY Coast Guard Towing Safety Advisory Committee; Vacancies AGENCY: United States Coast Guard. ACTION... Safety Advisory Committee (TSAC). TSAC advises the Coast Guard on matters relating to shallow- draft inland and coastal waterway navigation and towing safety. DATES: Applications for TSAC membership...

  6. 33 CFR 164.78 - Navigation under way: Towing vessels.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Navigation under way: Towing vessels. 164.78 Section 164.78 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.78 Navigation under way: Towing vessels. (a) The owner, master,...

  7. 15. VIEW NORTHNORTHEAST OF TOW TANK No. 2, DEWATERED. ENCLOSED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW NORTH-NORTHEAST OF TOW TANK No. 2, DEWATERED. ENCLOSED AREAS AT BACK OF TUNNEL IS A HOUSING FOR CONDUCTING PERFORMANCE TESTING ON AIRCRAFT MODELS IN A VORTEX. - NASA Langley Research Center, Seaplane Towing Channel, 108 Andrews Street, Hampton, Hampton, VA

  8. 33 CFR 83.24 - Towing and pushing (Rule 24).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... line above the sternlight; and (5) When the length of the tow exceeds 200 meters, a diamond shape where... exceeds 200 meters, a diamond shape where it can best be seen. (f) Vessels being towed alongside or pushed... alongside each other shall be lighted as one vessel or object; (4) A diamond shape at or near the...

  9. 33 CFR 83.24 - Towing and pushing (Rule 24).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... line above the sternlight; and (5) When the length of the tow exceeds 200 meters, a diamond shape where... exceeds 200 meters, a diamond shape where it can best be seen. (f) Vessels being towed alongside or pushed... alongside each other shall be lighted as one vessel or object; (4) A diamond shape at or near the...

  10. 33 CFR 83.24 - Towing and pushing (Rule 24).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... line above the sternlight; and (5) When the length of the tow exceeds 200 meters, a diamond shape where... exceeds 200 meters, a diamond shape where it can best be seen. (f) Vessels being towed alongside or pushed... alongside each other shall be lighted as one vessel or object; (4) A diamond shape at or near the...

  11. 75 FR 7615 - Towing Safety Advisory Committee; Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-22

    ...The Towing Safety Advisory Committee and its working group on the Revision of Navigation and Vessel Inspection Circular 04-01 will meet in New Orleans, LA. The Committee will also discuss various issues relating to shallow-draft inland and coastal waterway navigation and towing safety. All meetings will be open to the...

  12. 77 FR 31631 - Towing Safety Advisory Committee; Vacancies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-29

    ... city with large towing centers of commerce and populated by high concentrations of towing industry and... discriminate in employment on the basis of race, color, religion, sex, national origin, political affiliation, sexual orientation, gender identity, marital status, disability and genetic information, age,...

  13. 77 FR 12863 - Towing Safety Advisory Committee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-02

    ... Register (73 FR 3316). For access to the docket to read background documents or comments received in... Towing Vessels notice of proposed rulemaking (76 FR 49976, August 11, 2011), the committee is... SECURITY Towing Safety Advisory Committee; Meeting AGENCY: Coast Guard, DHS. ACTION: Notice of...

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

    NASA Astrophysics Data System (ADS)

    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

  15. MAGSAT: Vector magnetometer absolute sensor alignment determination

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.

    1981-01-01

    A procedure is described for accurately determining the absolute alignment of the magnetic axes of a triaxial magnetometer sensor with respect to an external, fixed, reference coordinate system. The method does not require that the magnetic field vector orientation, as generated by a triaxial calibration coil system, be known to better than a few degrees from its true position, and minimizes the number of positions through which a sensor assembly must be rotated to obtain a solution. Computer simulations show that accuracies of better than 0.4 seconds of arc can be achieved under typical test conditions associated with existing magnetic test facilities. The basic approach is similar in nature to that presented by McPherron and Snare (1978) except that only three sensor positions are required and the system of equations to be solved is considerably simplified. Applications of the method to the case of the MAGSAT Vector Magnetometer are presented and the problems encountered discussed.

  16. High temperature superconductive flux gate magnetometer

    SciTech Connect

    Gershenson, M. )

    1991-03-01

    This paper proposes a different type of HTS superconducting magnetometer based on the non-linear magnetic behavior of bulk HTS materials. The device design is based on the generation of second harmonics which arise as a result of non-linear magnetization observed in Type-II superconductors. Even harmonics are generated from the non-linear interaction of an ac excitation signal with an external DC magnetic field which acts as a bias signal.

  17. Superconducting Nanobridge SQUID Magnetometers for Spin Sensing

    NASA Astrophysics Data System (ADS)

    Antler, Natania

    As the cutting edge of science and technology pushes towards smaller length scales, sensing technologies with nanoscale precision become increasingly important. In this thesis I will discuss the optimization and application of a 3D nanobridge SQUID magnetometer for studying solid state spin systems, in particular for sensing impurity spins in diamond. Solid state spins have proposed applications in memory and computation for both classical and quantum computing. Isolated spins typically have longer coherence times, making them attractive qubit candidates, but necessitating the development of very sensitive detectors for readout. This 3D nanobridge SQUID combines the exquisite spatial sensitivity of a traditional nanoSQUID with a large non-linearity on par with a tunnel junction SQUID. This allows us to build a highly sensitive magnetometer which can act as both an efficient flux transducer as well as a nearly quantum limited lumped Josephson Parametric Amplifier. We show that the device has a minimum flux noise of 17 +/- 0.9 nphi0/Hz1/2 with only a factor of ˜2.5 increase in flux noise up to 61 mT. A second generation device with a smaller capacitor achieves field tolerance up to 75 mT. The maximal bandwidth values range from 25-40 MHz in the parametric amplification regime to 70 MHz in the linear regime. This combination of large bandwidth, low flux noise, large flux coupling and field tolerance make this sensor a promising candidate for near-single-spin dynamics measurements. In the last part of this thesis we begin to demonstrate the utility of a nanobridge SQUID magnetometer for characterizing spin systems in the solid state. We use the magnetometer to measure the decay characteristics of P1 centers in diamond. We find that the spin-lattice relaxation time varies with temperature, with an order of magnitude decrease in the decay time between 25 mK and 370 mK.

  18. Fluxgate magnetometers for outer planets exploration

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.

    1974-01-01

    The exploration of the interplanetary medium and the magnetospheres of the outer planets requires the implementation of magnetic field measuring instrumentation with wide dynamic range, high stability, and reliability. The fluxgate magnetometers developed for the Pioneer 11 and Mariner-Jupiter-Saturn missions are presented. These instruments cover the range of .01 nT to 2 million nT with optimum performance characteristics and low power consumption.

  19. Science Highlights from the Cassini magnetometer instrument

    NASA Astrophysics Data System (ADS)

    Dougherty, Michele

    2014-05-01

    The Cassini dual technique magnetometer instrument has been taking data in the Saturn system for the last 10 years. Science highlights encompass topics including the magnetosphere and its aurora, the internal dynamo magnetic field of Saturn, the icy satellites and Enceladus in particular, as well as the large moon Titan. The science discoveries will be described as well as important science observations yet to be made in the remaining 4 years of the mission.

  20. Engineered Polymer Composites Through Electrospun Nanofiber Coating of Fiber Tows

    NASA Technical Reports Server (NTRS)

    Kohlman, Lee W.

    2013-01-01

    Toughening and other property enhancements of composite materials are typically implemented by-modifying the bulk properties of the constituents, either the fiber or matrix materials. This often leads to difficulties in processing and higher material costs. Many composites consist of tows or yarns (thousands of individual fibers) that are either filament wound or processed into a fabric by weaving or braiding. The matrix material can be added to the tow or fabric before final processing, resulting in a prepreg material, or infused into the fiber material during final processing by a variety of methods. By using a direct electrospun deposition method to apply thermoplastic nanofiber to the surface of the tows, the tow-tow interface in the resulting composite can be modified while using otherwise conventional materials and handling processes. Other materials of interest could also be incorporated into the electrospun precursor.

  1. Integration of micro-fabricated atomic magnetometers on military systems

    NASA Astrophysics Data System (ADS)

    Schultz, Gregory; Mhaskar, Rahul; Prouty, Mark; Miller, Jonathan

    2016-05-01

    A new generation of ultra-high sensitivity magnetic sensors based on innovative micro-electromechanical systems (MEMS) are being developed and incorporated into military systems. Specifically, we are currently working to fully integrate the latest generation of MicroFabricated Atomic Magnetometers (MFAMs) developed by Geometrics on defense mobility systems such as unmanned systems, military vehicles and handheld units. Recent reductions in size, weight, and power of these sensors has enabled new deployment opportunities for improved sensitivity to targets of interest, but has also introduced new challenges associated with noise mitigation, mission configuration planning, and data processing. Our work is focused on overcoming the practical aspects of integrating these sensors with various military platforms. Implications associated with utilizing these combined sensor systems in working environments are addressed in order to optimize signal-to-noise ratios, detection probabilities, and false alarm mitigation. Specifically, we present collaborative work that bridges the gap between commercial specialists and operation platform integration organizations including magnetic signature characterization and mitigation as well as the development of simulation tools that consider a wide array of sensor, environmental, platform, and mission-level parameters. We discuss unique deployment concepts for explosive hazard target geolocation, and data processing. Applications include configurations for undersea and underground threat detection - particularly those associated with stationary or mobile explosives and compact metallic targets such as munitions, subsea threats, and other hazardous objects. We show the potential of current and future features of miniaturized magnetic sensors including very high magnetic field sensitivities, bandwidth selectivity, and array processing.

  2. Broadband performance of a moving time reversing array

    NASA Astrophysics Data System (ADS)

    Sabra, Karim G.; Dowling, David R.

    2003-09-01

    Acoustic time reversal exploits reciprocity between sources and receivers to generate backward propagating waves that automatically focus at their point of origin. In underwater acoustics, an array of transducers that can both transmit and receive, referred to as a time reversing array (TRA) or time reversal mirror (TRM), generates the back-propagating waves. Such arrays have been shown to spatially and temporally focus sound in unknown complicated multipath environments, and are therefore of interest for active sonar and underwater communication applications. Although stationary vertical linear TRAs have been favored in prior studies, practical applications of acoustic time reversal in underwater environments are likely to involve towed, tilted, horizontal, or bottom-mounted arrays. In particular, array motion introduces Doppler effects and eliminates source-receiver reciprocity, two factors that potentially impact the automatic focusing capability of TRAs. This paper presents the results from a theoretical and computational investigation into how array motion and orientation influence TRA retrofocusing in the shallow ocean. Here, the TRA tow speed is assumed constant, and the array is assumed to be straight and linear (vertical, horizontal, or tilted). And, for simplicity, the TRA is assumed to respond to a stationary point source emitting a broadband pulse. When a TRA moves, the retrofocus is predicted to shift in the direction of array motion due to the translation of the array between its reception and broadcast times. In addition, the performance of a towed horizontal TRA is predicted to degrade more rapidly with towing speed than that of an equivalent (but clearly idealized) towed vertical array because of range-dependent Doppler phase differences that do not influence the vertical array. However, short tilted arrays may approach vertical array performance and appear to be a potentially versatile compromise for implementing TRA concepts in active sonar or

  3. Broadband performance of a moving time reversing array.

    PubMed

    Sabra, Karim G; Dowling, David R

    2003-09-01

    Acoustic time reversal exploits reciprocity between sources and receivers to generate backward propagating waves that automatically focus at their point of origin. In underwater acoustics, an array of transducers that can both transmit and receive, referred to as a time reversing array (TRA) or time reversal mirror (TRM), generates the back-propagating waves. Such arrays have been shown to spatially and temporally focus sound in unknown complicated multipath environments, and are therefore of interest for active sonar and underwater communication applications. Although stationary vertical linear TRAs have been favored in prior studies, practical applications of acoustic time reversal in underwater environments are likely to involve towed, tilted, horizontal, or bottom-mounted arrays. In particular, array motion introduces Doppler effects and eliminates source-receiver reciprocity, two factors that potentially impact the automatic focusing capability of TRAs. This paper presents the results from a theoretical and computational investigation into how array motion and orientation influence TRA retrofocusing in the shallow ocean. Here, the TRA tow speed is assumed constant, and the array is assumed to be straight and linear (vertical, horizontal, or tilted). And, for simplicity, the TRA is assumed to respond to a stationary point source emitting a broadband pulse. When a TRA moves, the retrofocus is predicted to shift in the direction of array motion due to the translation of the array between its reception and broadcast times. In addition, the performance of a towed horizontal TRA is predicted to degrade more rapidly with towing speed than that of an equivalent (but clearly idealized) towed vertical array because of range-dependent Doppler phase differences that do not influence the vertical array. However, short tilted arrays may approach vertical array performance and appear to be a potentially versatile compromise for implementing TRA concepts in active sonar or

  4. The MAGSAT vector magnetometer: A precision fluxgate magnetometer for the measurement of the geomagnetic field

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.; Scearce, C. S.; Seek, J.; Scheifele, J.

    1978-01-01

    A description of the precision triaxial fluxgate magnetometer to be flown aboard the MAGSAT spacecraft is presented. The instrument covers the range of + or - 64,000 nT with a resolution of + or - 0.5 nT, an intrinsic accuracy of + or - 0.001% of full scale and an angular alignment stability of the order of 2 seconds of arc. It was developed at NASA's Goddard Space Flight Center and represents the state-of-the-art in precision vector magnetometers developed for spaceflight use.

  5. 33 CFR 163.05 - Tows of seagoing barges within inland waters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Tows of seagoing barges within... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY TOWING OF BARGES § 163.05 Tows of seagoing barges within inland waters. (a) The tows of seagoing barges when navigating the inland waters of the United...

  6. 46 CFR 27.201 - What are the requirements for general alarms on towing vessels?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false What are the requirements for general alarms on towing vessels? 27.201 Section 27.201 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS TOWING VESSELS Fire-Protection Measures for Towing Vessels § 27.201 What are the requirements for general alarms on towing vessels? (a) You...

  7. The atomic magnetometer: A new era in biomagnetism

    NASA Astrophysics Data System (ADS)

    Wakai, Ronald T.

    2014-11-01

    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.

  8. Optimization of buffer gas pressure for Rb atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Chen, Chang; Liu, Xiaohu; Qu, Tianliang; Yang, Kaiyong

    2015-08-01

    The optimization of buffer gas pressure is very important to improve the performance of the rubidium (Rb) atomic magnetometer. In this paper we briefly introduce the basic principle and the experimental method of the rubidium magnetometer based on Faraday rotation effect, and describe the factors affecting the magnetometer sensitivity, then analyze and summarize the mechanism of the influence of spin-exchange, spin-destruction collisions, radiation trapping and the spin diffusion on spin relaxation of Rb atoms. Based on this, the relationship between the rubidium magnetometer sensitivity, the spin relaxation rate and the gas chamber conditions (buffer gas pressure, the bubble radius, measuring temperature) is established. Doing calculations by the simulation software, how the magnetometer sensitivity and the relaxation rate vary with the gas chamber conditions can be seen; finally, the optimal values of the buffer gas pressure under certain gas chamber conditions are obtained. The work is significant for the engineering development of rubidium magnetometer.

  9. The atomic magnetometer: A new era in biomagnetism

    SciTech Connect

    Wakai, Ronald T.

    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.

  10. International solar polar mission: The vector helium magnetometer

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The functional requirements for the vector helium magnetometer (VHM) on the Solar Polar spacecraft are presented. The VHM is one of the two magnetometers on board that will measure the vector magnetic field along the Earth to Jupiter transfer trajectory, as well as in the vicinity of Jupiter and along the solar polar orbit following the Jupiter encounter. The interconnection between these two magnetometers and their shared data processing unit is illustrated.

  11. Aeroelastic Tailoring via Tow Steered Composites

    NASA Technical Reports Server (NTRS)

    Stanford, Bret K.; Jutte, Christine V.

    2014-01-01

    The use of tow steered composites, where fibers follow prescribed curvilinear paths within a laminate, can improve upon existing capabilities related to aeroelastic tailoring of wing structures, though this tailoring method has received relatively little attention in the literature. This paper demonstrates the technique for both a simple cantilevered plate in low-speed flow, as well as the wing box of a full-scale high aspect ratio transport configuration. Static aeroelastic stresses and dynamic flutter boundaries are obtained for both cases. The impact of various tailoring choices upon the aeroelastic performance is quantified: curvilinear fiber steering versus straight fiber steering, certifiable versus noncertifiable stacking sequences, a single uniform laminate per wing skin versus multiple laminates, and identical upper and lower wing skins structures versus individual tailoring.

  12. Magnetometers for Geoscience (Christiaan Huygens Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Korepanov, V.

    2009-04-01

    Measuring the Earth's magnetic field is one of the first metrological actions of humankind, traceable till about 5000 years BC. It is remarkable that the interest in magnetic fields measurements still is growing and the scope of their applications is getting wider and wider. The progress in the recent 20-30 years in the development of magnetometers of different kinds is highly impressive. Currently practically all scales of the magnetic field values can be measured - from the huge magnetic fields of astronomical objects down to atto-Tesla levels. A modern flux-gate magnetometer (FGM) may cover an amazing dynamic range of the magnetic field, ranging from 10-4 down to 10-12 T, and even lower. The second most important parameter, the zero line drift, may reach below 10-5 of the full measurement scale per year. Development of state of the art FGMs requires profound research activity in various science disciplines: mathematics, metrology, electronics and material science to name a few. This talk reviews the principles of various types of existing magnetometers and their main performance aspects are compared. It is shown that the most suitable type of instrument for measurements of the magnetic fields in the range applicable for geosciences is the FGM. A few highlights of recent developments of FGMs, with record parameters concerning noise level and power consumption, are given. Techniques to lower the noise to a cutting edge level are described and a new physical phenomenon discovered during this development work is reported and explained. Advancement in flux-gate magnetometry is discussed and a few specific examples are presented: a) a one-second INTERMAGNET-compatible FGM, b) a super-low power FGM, c) the lowest available noise FGM and d) the smallest but sensitive FGM for nano-satellites. Finally some applications for FGM use in geosciences are given and envisaged progress in the future development in the field of magnetic observations is discussed.

  13. Thermomechanical Behavior of Advanced SiC Fiber Multifilament Tows

    NASA Technical Reports Server (NTRS)

    Yun, Hee Mann; DiCarlo, James A.

    1997-01-01

    In order to relate single fiber behavior to multiple fiber behavior in composites, fast-fracture tensile strength, creep, and stress-rupture studies were conducted on advanced SiC fiber multifilament tows in the temperature range from 20 to 1400 C in air as well as in inert environments. For conditions of small fiber creep (short times and low temperatures), the tow results of this study confirm the ability of limited single fiber data to model the strength behavior of multiple fibers in a bundle. For conditions of high creep (long times and high temperatures), further studies are needed to explain tow rupture behavior being better than average single fiber behavior.

  14. Thermal Testing of Tow-Placed, Variable Stiffness Panels

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey; Guerdal, Zafer

    2001-01-01

    Commercial systems for precise placement of pre-preg composite tows are enabling technology that allows fabrication of advanced composite structures in which the tows may be precisely laid down along curvilinear paths within a given ply. For laminates with curvilinear tow paths, the fiber orientation angle varies continuously throughout the laminate, and is not required to be straight and parallel in each ply as in conventional composite laminates. Hence, the stiffness properties vary as a function of location in the laminate, and the associated composite structure is called a "variable stiffness" composite structure.

  15. Magnetometer Based on Optoelectronic Microwave Oscillator

    NASA Technical Reports Server (NTRS)

    Maleki, Lute; Strekalov, Dmitry; Matsko, Andrey

    2005-01-01

    proposed instrument, intended mainly for use as a magnetometer, would include an optoelectronic oscillator (OEO) stabilized by an atomic cell that could play the role of a magnetically tunable microwave filter. The microwave frequency would vary with the magnetic field in the cell, thereby providing an indication of the magnetic field. The proposed magnetometer would offer a combination of high accuracy and high sensitivity, characterized by flux densities of less than a picotesla. In comparison with prior magnetometers, the proposed magnetometer could, in principle, be constructed as a compact, lightweight instrument: It could fit into a package of about 10 by 10 by 10 cm and would have a mass <0.5 kg. As described in several prior NASA Tech Briefs articles, an OEO is a hybrid of photonic and electronic components that generates highly spectrally pure microwave radiation, and optical radiation modulated by the microwave radiation, through direct conversion between laser light and microwave radiation in an optoelectronic feedback loop. As used here, "atomic cell" signifies a cell containing a vapor, the constituent atoms of which can be made to undergo transitions between quantum states, denoted hyperfine levels, when excited by light in a suitable wavelength range. The laser light must be in this range. The energy difference between the hyperfine levels defines the microwave frequency. In the proposed instrument (see figure), light from a laser would be introduced into an electro-optical modulator (EOM). Amplitude-modulated light from the exit port of the EOM would pass through a fiber-optic splitter having two output branches. The light in one branch would be sent through an atomic cell to a photodiode. The light in the other branch would constitute the microwave-modulated optical output. Part of the light leaving the atomic cell could also be used to stabilize the laser at a frequency in the vicinity of the desired hyperfine or other quantum transition. The

  16. Pulsed 3-Axis Vector SERF Magnetometer

    NASA Astrophysics Data System (ADS)

    Hedges, Morgan; Romalis, Michael

    2016-05-01

    We demonstrate a 3-axis atomic vector magnetometer operating in the SERF regime, using a single beam path, and capable of operating in Earth's field using field feedback. It has similar sensitivity along all 3 axes that is fundamentally limited by photon and atom shot noise. The scheme uses a high intensity pump pulse to polarize Rb atoms in ~ 1 μs and a sequence of magnetic field pulses applied while the atoms are monitored during free precession. The sequence used provides minimal sensitivity to pulse errors, while also allowing unambiguous discrimination between external magnetic fields and misalignment between laser and magnetic coil axes.

  17. Autonomous navigation system based on GPS and magnetometer data

    NASA Technical Reports Server (NTRS)

    Julie, Thienel K. (Inventor); Richard, Harman R. (Inventor); Bar-Itzhack, Itzhack Y. (Inventor)

    2004-01-01

    This invention is drawn to an autonomous navigation system using Global Positioning System (GPS) and magnetometers for low Earth orbit satellites. As a magnetometer is reliable and always provides information on spacecraft attitude, rate, and orbit, the magnetometer-GPS configuration solves GPS initialization problem, decreasing the convergence time for navigation estimate and improving the overall accuracy. Eventually the magnetometer-GPS configuration enables the system to avoid costly and inherently less reliable gyro for rate estimation. Being autonomous, this invention would provide for black-box spacecraft navigation, producing attitude, orbit, and rate estimates without any ground input with high accuracy and reliability.

  18. A Compact, High Performance Atomic Magnetometer for Biomedical Applications

    PubMed Central

    Shah, Vishal K.; Wakai, Ronald T.

    2013-01-01

    We present a highly sensitive room-temperature atomic magnetometer (AM), designed for use in biomedical applications. The magnetometer sensor head is only 2×2×5 cm3 and is constructed using readily available, low-cost optical components. The magnetic field resolution of the AM is <10 fT/√Hz, which is comparable to cryogenically cooled superconducting quantum interference device (SQUID) magnetometers. We present side-by-side comparisons between our AM and a SQUID magnetometer, and show that equally high quality magnetoencephalography (MEG) and magnetocardiography (MCG) recordings can be obtained using our AM. PMID:24200837

  19. Postflight evaluation of the solar maximum spacecraft magnetometers

    NASA Technical Reports Server (NTRS)

    Dunham, W. D.

    1985-01-01

    The Solar Maximum Mission spacecraft was launched February 14, 1980 from Cape Kennedy. Attached to one side of the spacecraft was the Modular Attitude Control System (MACS). Two Schonstedt magnetometers were located within the MACS module. Although primarily used as a backup attitude determination system during the Solar Maximum Repair Mission, the magnetometers were instrumental in stabilizing the spacecraft. In October of 1984 the Solar Maximum magnetometers were returned to Schonstedt Instrument Company for postflight analysis, where they were subjected to the same electrical performance tests performed prior to use. In both instances the magnetometer performance was exceptional. Postflight test data nearly duplicated preflight test data.

  20. Automated system for the calibration of magnetometers

    SciTech Connect

    Petrucha, Vojtech; Kaspar, Petr; Ripka, Pavel; Merayo, Jose M. G.

    2009-04-01

    A completely nonmagnetic calibration platform has been developed and constructed at DTU Space (Technical University of Denmark). It is intended for on-site scalar calibration of high-precise fluxgate magnetometers. An enhanced version of the same platform is being built at the Czech Technical 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.

  1. Vectorial atomic magnetometer using electronic and nuclear

    NASA Astrophysics Data System (ADS)

    Zhou, Binquan; Chen, Linlin; Lei, Guanqun; Meng, Xiaofeng; Fang, Jiancheng

    2015-05-01

    We present an experimental study of a vectorial atomic magnetometer, which can measure three-dimensional magnetic field simultaneously. The experimental setup for magnetometer has been described in the literature. Where an external magnetic field is added parallel to the pumping light, that the goal is to switch the nuclear spin state form an undesired state to the desired state creating a gas whose atoms are completely aligned. A probe light is added perpendicular to the pumping light. When there is transverse alternating magnetic field, the probe light will be modulated by the spin procession. We obtain the two transverse magnetic fields signal through the in-phase and out-of-phase of a lock-in amplifier, At the same time, the external magnetic field held constant relative to the external frequency reference, two nuclear signals can be used to measure z vertical magnetic field by comparing the measured two nuclear signal to a second stable reference signal generated by the same external frequency. Once the output signal is feedbacked to the coil, the external three-dimensional magnetic field is measured in real-time. The dynamic range can be adjusted through the external magnetic field,so this method can be used both in the magnetic surveys and in the prospecting field range. This work was supported in part by the NSF of China (61227902,61374210,61121003).

  2. Juno Magnetometer Observations in the Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Connerney, J. E.; Oliversen, R. J.; Espley, J. R.; MacDowall, R. J.; Schnurr, R.; Sheppard, D.; Odom, J.; Lawton, P.; Murphy, S.; Joergensen, J. L.; Joergensen, P. S.; Merayo, J. M.; Denver, T.; Bloxham, J.; Smith, E. J.; Murphy, N.

    2013-12-01

    The Juno spacecraft enjoyed a close encounter with Earth on October 9, 2013, en route to Jupiter Orbit Insertion (JOI) on July 5, 2016. The Earth Flyby (EFB) provided a unique opportunity for the Juno particles and fields instruments to sample mission relevant environments and exercise operations anticipated for orbital operations at Jupiter, particularly the period of intense activity around perijove. 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. This very capable magnetic observatory sampled the Earth's magnetic field at 64 vector samples/second throughout passage through the Earth's magnetosphere. We present observations of the Earth's magnetic field and magnetosphere obtained throughout the encounter and compare these observations with those of other Earth-orbiting assets, as available, and with particles and fields observations acquired by other Juno instruments operated during EFB.

  3. Magnetoresistive magnetometer for space science applications

    NASA Astrophysics Data System (ADS)

    Brown, P.; Beek, T.; Carr, C.; O'Brien, H.; Cupido, E.; Oddy, T.; Horbury, T. S.

    2012-02-01

    Measurement of the in situ dc magnetic field on space science missions is most commonly achieved using instruments based on fluxgate sensors. Fluxgates are robust, reliable and have considerable space heritage; however, their mass and volume are not optimized for deployment on nano or picosats. We describe a new magnetometer design demonstrating science measurement capability featuring significantly lower mass, volume and to a lesser extent power than a typical fluxgate. The instrument employs a sensor based on anisotropic magnetoresistance (AMR) achieving a noise floor of less than 50 pT Hz-1/2 above 1 Hz on a 5 V bridge bias. The instrument range is scalable up to ±50 000 nT and the three-axis sensor mass and volume are less than 10 g and 10 cm3, respectively. The ability to switch the polarization of the sensor's easy axis and apply magnetic feedback is used to build a driven first harmonic closed loop system featuring improved linearity, gain stability and compensation of the sensor offset. A number of potential geospace applications based on the initial instrument results are discussed including attitude control systems and scientific measurement of waves and structures in the terrestrial magnetosphere. A flight version of the AMR magnetometer will fly on the TRIO-CINEMA mission due to be launched in 2012.

  4. X-34 on lakebed prior to tow tests

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Following initial captive flight tests last year at NASA's Dryden Flight Research Center, Edwards Air Force Base, California, the X-34 technology demonstrator began a new series of tests last week in which it is being towed behind a semi-truck and released to coast on the Edwards dry lakebed. On July 20, 2000, it was towed and released twice at speeds of five and 10 miles per hour. On July 24, 2000, it was towed and released twice at 10 and 30 miles per hour. Twelve tests are planned during which the X-34 will be towed for distances up to 10,000 feet and released at speeds up to 80 miles per hour. The test series is expected to last at least six weeks.

  5. Composites from powder coated towpreg - Studies with variable tow sizes

    NASA Technical Reports Server (NTRS)

    Hugh, Maylene K.; Marchello, Joseph M.; Baucom, Robert M.; Johnston, Norman J.

    1992-01-01

    Part fabrication from composite materials usually costs less when larger fiber tow bundles are used. On the other hand, mechanical properties generally are lower for composites made using larger size tows. This situation gives rise to a choice between costs and properties in determining the best fiber tow bundle size to employ in preparing prepreg materials for part fabrication. To address this issue, unidirectional and eight harness satin fabric composite specimens were fabricated from 3k, 6k, and 12k carbon fiber reinforced LARC-TPI powder coated towpreg. Short beam shear strengths and longitudinal and transverse flexure properties were obtained for the unidirectional specimens. Tension properties were obtained for the eight harness satin woven towpreg specimens. Knowledge of the variation of properties with tow size may serve as a guide in material selection for part fabrication.

  6. NASA Dryden Towed Glider Air-Launch Concept

    NASA Video Gallery

    NASA Dryden Flight Research Center is developing a novel space access, rocket launching technique called the Towed Glider Air-Launch Concept. The idea is to build a relatively inexpensive, remotely...

  7. Method for Coating a Tow with an Electrospun Nanofiber

    NASA Technical Reports Server (NTRS)

    Kohlman, Lee W. (Inventor); Roberts, Gary D. (Inventor)

    2015-01-01

    Method and apparatus for enhancing the durability as well as the strength and stiffness of prepreg fiber tows of the sort used in composite materials are disclosed. The method involves adhering electrospun fibers onto the surface of such composite materials as filament-wound composite objects and the surface of prepreg fiber tows of the sort that are subsequently used in the production of composite materials of the filament-wound, woven, and braided sorts. The apparatus performs the methods described herein.

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

    NASA Technical Reports Server (NTRS)

    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.

  9. Magnetometers. (Latest citations from the US Patent database). Published Search

    SciTech Connect

    Not Available

    1992-11-01

    The bibliography contains citations of selected patents concerning magnetometer devices and equipment used in detection, control, and survey systems. The design, fabrication, and application of magnetometers using thin film, optical, nuclear, and electron beam technologies are discussed. Applications include navigation systems, vehicle direction control, and natural resource exploration. (Contains a minimum of 204 citations and includes a subject term index and title list.)

  10. A 16-channel high-Tc SQUID-magnetometer system for magnetocardiogram mapping

    NASA Astrophysics Data System (ADS)

    Yokosawa, Koichi; Tsukamoto, Akira; Suzuki, Daisuke; Kandori, Akihiko; Miyashita, Tsuyoshi; Ogata, Kuniomi; Seki, Yusuke; Tsukada, Keiji

    2003-12-01

    A compact, light and easy-to-handle magnetocardiograph (MCG) has been developed. The MCG consists of a sensor array with superconducting-quantum-interference-device magnetometers made of a high-critical temperature superconductor, arranged in a 4 × 4 matrix, and operated in a vertical magnetically shielding cylinder (1.7 m high and 1 m in diameter). Each magnetometer is paired with each of its adjacent magnetometers, and the difference between the respective outputs provides us with a measure of magnetic gradient. This configuration for the electronic gradiometers cancels out the environmental magnetic field noise within the shielding cylinder. We use the data from the multiple gradiometers to construct a current arrow map that describes the distribution of original current vectors in the area being measured. We used the fabricated MCG to record magnetocardiograms of healthy volunteers. The smallest signals, i.e., the P-waves, were clearly detected without averaging. The current arrow maps obtained from the single-beat magnetocardiograms indicate the feasibility of clinical application of this MCG.

  11. Magnetic field satellite /MAGSAT/ spacecraft vector magnetometer calibration

    NASA Technical Reports Server (NTRS)

    Hinkal, S. W.

    1980-01-01

    The low-flying MAGSAT spacecraft, launched October 30, 1979, included a Vector Magnetometer to accurately map the magnitude and direction of the magnetic field of the earth. Calibration of the magnetometer included arc-second precision determination of the relative orientations of the three sensor axes in a coordinate system defined by optical references. This determination began with laboratory measurements of the relative alignments of optical components mounted with the magnetometer. The actual calibration procedure then consisted basically of accurate and repeatable positioning of the Vector Magnetometer within a unique magnetic test facility which nulls the earth's magnetic field, then generates magnetic fields of various orientations and strengths. Analysis of the magnetometer sensor outputs together with the position and alignment data then gave the axes orientations. We used precision theodolites and methods related to surveying techniques to achieve the accurate positioning and optical component alignment measurements. The final calibration accuracy exceeded results previously achieved in the facility.

  12. Investigation of the Forces Acting on Gliders in Automobile-pulley-winch and Airplane Towed Flight

    NASA Technical Reports Server (NTRS)

    Klemperer, W B

    1942-01-01

    The magnitude, the direction, and the fluctuation of towing forces exerted upon gliders by towing them aloft behind an automobile, by means of a winch, and by airplane were measured under a variety of conditions covering a range from gentle to severe types of operation. For these tests the towing forces did not exceed 92 percent of the gross weight of the glider. The results indicate that in pulley and winch towing the towing forces are of about the same magnitude as in automobile towing. Speed increases in the accelerated phases of the towing jerks encountered in airplane towing can readily become critical as speeds in excess of placard speeds can be attained. Passage through the slipstream of the towing airplane can be equivalent to a severe gust that, at high speed, may impose high wing loads and require large control moments.

  13. Magnetic-field-compensation optical vector magnetometer.

    PubMed

    Papoyan, Aram; Shmavonyan, Svetlana; Khanbekyan, Alen; Khanbekyan, Karen; Marinelli, Carmela; Mariotti, Emilio

    2016-02-01

    A concept for an optical magnetometer used for the measurement of magnitude and direction of a magnetic field (B-field) in two orthogonal directions is developed based on double scanning of a B-field to compensate the measured field to zero value, which is monitored by a resonant magneto-optical process in an unshielded atomic vapor cell. Implementation of the technique using the nonlinear Hanle effect on the D2 line of rubidium demonstrates viability and efficiency of the proposed concept. The ways to enhance characteristics of the suggested technique and optimize its performance, as well as the possible extension to three-axis magnetometry, are discussed. PMID:26836097

  14. Towed-Grid Studies of Quantum Turbulence

    NASA Astrophysics Data System (ADS)

    Liu, Shu-Chen; Labbe, Greg; Ihas, Gary G.

    2006-11-01

    We produce Homogeneous Isotropic Quantum Turbulence (HIQT) in liquid helium at 20 mK to compare with classical experiments and theories. Specifically, in the absence of viscosity, through what path does the turbulence decay? To produce HIQT we must quickly accelerate a grid to about 1 m/s in a channel of superfluid helium, tow it for 1 cm at a nearly constant speed, and then stop it equally quickly. To avoid joule and eddy current heating of the liquid helium, a magnetically shielded superconducting linear motor has been built, guided by simulations, along with the current pulses control program written in LabView with an embedded C compiler. The simulations, design process, and the experimental data demonstrating the functioning motor will be presented. We measure the HIQT energy decay mechanism using a calorimetric technique. Recent theory suggests the decay occurs through a Kelvin-wave cascade on the vortex lines which couples the initially large turbulent eddies to the short wavelength phonon spectrum of the liquid, yielding a characteristic rate of temperature rise. Doped germanium thermometers less than 300 μm diameter immersed in the turbulent helium allow fast calorimetric measurements to be made. The decay of turbulence is detected by the rate of temperature rise in the isolated cell after the grid is pulled.

  15. Mid-Atlantic Ridge at 13-14N: Evidence of Unstable Seafloor Spreading Processes From Deep-Towed Magnetic Measurements

    NASA Astrophysics Data System (ADS)

    Searle, R.; Mallows, C.; Cipcigan, F.; Party, J. S.

    2007-12-01

    During cruise JC007 in March-April 2007 we recorded total magnetic field anomalies over two active and one defunct oceanic core complex (OCC) and the intervening seafloor. Measurements were made by towed magnetometer at the sea surface, and by the TOBI deep-towed vehicle approximately 400 m above seafloor, along 13 E-W lines about 60 km long and spaced 3 to 6 km apart. Sea-surface data show a fairly coherent central anomaly on most lines, though on some it is significantly displaced from the spreading axis as indicated by bathymetry and side-scan sonar data. Modelling in terms of a standard, simple (but probably unrealistic), continuous reversal sequence requires total spreading rates ranging from about 15 to 40 km/Myr with offsets of the axis up to 20 km and highly asymmetric spreading. The deep-towed data were corrected for the heading-dependent magnetic effects of the TOBI vehicle before inversion to crustal magnetisation using the 2D Parker & Huestis (1974) procedure. These results were checked by comparing with inversions of the sea-surface field, which shows similar features at reduced resolution. The deep-towed inversion results show a rather incoherent magnetisation pattern. The central magnetisation high is nowhere more than 13 km wide, only 70% of the expected width of the Brunhes here, and several profiles yield apparently negative magnetisation over areas we expect to be of Brunhes age based on sonar and bathymetry data. This may due to a combination of destruction of magnetisation by faulting (Hussenoeder at al., 1996), departure from the 2D geometry assumed for the inversions, and departure (via tectonic rotation) from the assumed constant magnetisation direction. We are now carrying out fully 3D inversions and forward modelling guided by the structural evidence provided by sidescan and bathymetry. These results will be presented and discussed in relation to the seafloor spreading history and structure of the region.

  16. Fine structure of methane hydrate-bearing sediments on the Blake Outer ridge as determined from deep-tow multichannel seismic data. (Reannouncement with new availability information). Final report

    SciTech Connect

    Rowe, M.M.; Gettrust, J.F.

    1993-01-01

    High-resolution, deep-tow multichannel seismic data are used to investigate the detailed structure of sediments containing methane hydrate. These data support thick, laterally extensive layers of methane hydrate-bearing sediment underlain by a bottom simulating reflector (BSR) and spatially discontinuous zones of hydrate within the sediments above the BSR depth where no BSR is present. These data resolve normal faults which extend from the surface through the BSR with apparent offsets of up to 20 m. A phase inversion identified at the top of the BSR shows that the material immediately beneath the BSR has anomalously low velocity, consistent with a layer of sediment containing free methane gas. The fault offsets along the BSR and consistent with a pressure change of approx. 200 kPa (approx. 2 bars) across the fault zone.... Directional ambient noise, Bottom scattering, Deep-towed array geophysical system, Towed array, Ocean-bottom seismometer

  17. High transition-temperature SQUID magnetometers and practical applications

    SciTech Connect

    Dantsker, E

    1997-05-01

    The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7{minus}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-SrTiO{sub 3}-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{sup {minus}1/2} at 1 Hz and 8.5 fT Hz{sup {minus}1/2} at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz{sup {minus}1/2} at 1 Hz and 18 fT Hz{sup {minus}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.

  18. The tole of towing services at motor vehicle crashes.

    PubMed

    Dean, L; Jame, W; Ryan, G A

    1975-08-16

    A survey of tow truck services operating in a defined area of the south-east suburbs of Melbourne was undertaken to determine their potential for delivering emergency medical care at the scene of crashes. Most towing firms have an association with a panel-beating shop, and operate within a limited area of one to three miles radius. The rapid response of tow trucks to crash scenes is due to their well-developed intelligence network of "spotters" and the short distances the trucks travel. Very little first aid is provided by the drivers, although one-fifth had some first aid training at some time. In about one-half of the calls to crashes a damaged vehicle is still at the scene, in about 20% an ambulance is called, and in about 5% a hospital admission occurs. Direct observation of 22 crashes suggests that on average, tow trucks arrive at a crash scene five minutes before the ambulance, and fifteen minutes before the police. There is a good case for making first aid training a preerequisite for issue of a tow truck operator's license. PMID:1160789

  19. Search Coil vs. Fluxgate Magnetometer Measurements at Interplanetary Shocks

    NASA Technical Reports Server (NTRS)

    Wilson, L.B., III

    2012-01-01

    We present magnetic field observations at interplanetary shocks comparing two different sample rates showing significantly different results. Fluxgate magnetometer measurements show relatively laminar supercritical shock transitions at roughly 11 samples/s. Search coil magnetometer measurements at 1875 samples/s, however, show large amplitude (dB/B as large as 2) fluctuations that are not resolved by the fluxgate magnetometer. We show that these fluctuations, identified as whistler mode waves, would produce a significant perturbation to the shock transition region changing the interpretation from laminar to turbulent. Thus, previous observations of supercritical interplanetary shocks classified as laminar may have been under sampled.

  20. Analysing harmonic motions with an iPhone’s magnetometer

    NASA Astrophysics Data System (ADS)

    Yavuz, Ahmet; Kağan Temiz, Burak

    2016-05-01

    In this paper, we propose an experiment for analysing harmonic motion using an iPhone’s (or iPad’s) magnetometer. This experiment consists of the detection of magnetic field variations obtained from an iPhone’s magnetometer sensor. A graph of harmonic motion is directly displayed on the iPhone’s screen using the Sensor Kinetics application. Data from this application was analysed with Eureqa software to establish the equation of the harmonic motion. Analyses show that the use of an iPhone’s magnetometer to analyse harmonic motion is a practical and effective method for small oscillations and frequencies less than 15–20 Hz.

  1. Structural Assessment of Advanced Composite Tow-Steered Shells

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey; Stanford, Bret K.; Hrinda, Glenn A.; Wang, Zhuosong; Martin, Robert a.; Kim, H. Alicia

    2013-01-01

    The structural performance of two advanced composite tow-steered shells, manufactured using a fiber placement system, is assessed using both experimental and analytical methods. The fiber orientation angles vary continuously around the shell circumference from 10 degrees on the shell crown and keel, to 45 degrees on the shell sides. The two shells differ in that one shell has the full 24-tow course applied during each pass of the fiber placement system, while the second shell uses the fiber placement system s tow drop/add capability to achieve a more uniform shell wall thickness. The shells are tested in axial compression, and estimates of their prebuckling axial stiffnesses and bifurcation buckling loads are predicted using linear finite element analyses. These preliminary predictions compare well with the test results, with an average agreement of approximately 10 percent.

  2. Air-Sea Interaction Measurements from the Controlled Towed Vehicle

    NASA Astrophysics Data System (ADS)

    Khelif, D.; Bluth, R. T.; Jonsson, H.; Barge, J.

    2014-12-01

    The Controlled Towed Vehicle (CTV) uses improved towed drone technology to actively maintain via a radar altimeter and controllable wing a user-set height that can be as low as the canonical reference height of 10 m above the sea surface. After take-off, the drone is released from the tow aircraft on a ~700-m stainless steel cable. We have instrumented the 0.23 m diameter and 2.13 m long drone with high fidelity instruments to measure the means and turbulent fluctuations of 3-D wind vector, temperature, humidity, pressure, CO2 and IR sea surface temperature. Data are recorded internally at 40 Hz and simultaneously transmitted to the tow aircraft via dedicated wireless Ethernet link. The CTV accommodates 40 kg of instrument payload and provides it with 250 W of continuous power through a ram air propeller-driven generator. Therefore its endurance is only limited by that of the tow aircraft.We will discuss the CTV development, the engineering challenges and solutions that have been successfully implemented to overcome them. We present results from recent flights as low as 9 m over the coastal ocean and comparisons of profiles and turbulent fluxes from the CTV and the tow aircraft. Manned aircraft operation at low-level boundary-layer flights is very limited. Dropsondes and UAS (Unmanned Aerial Systems) and UAS are alternates for measurements near the ocean surface. However, dropsondes have limited sensor capability and do not measure fluxes, and most present UAS vehicles do not have the payload and power capacity nor the low-flying ability in high winds over the oceans. The CTV therefore, fills a needed gap between the dropsondes, in situ aircraft, and UAS. The payload, capacity and power of the CTV makes it suitable for a variety of atmospheric research measurements. Other sensors to measure aerosol, chemistry, radiation, etc., could be readily accommodated in the CTV.

  3. High- Tc thin-film magnetometer

    SciTech Connect

    Miklich, A.H.; Wellstood, F.C.; Kingston, J.J.; Clarke, J. ); Colclough, M.S. ); Cardona, A.H.; Bourne, L.C.; Olson, W.L.; Eddy, M.M. )

    1990-09-01

    We have constructed and tested high-{Tc} magnetometers by coupling a high-{Tc} thin-film Superconducting QUantum Interference Device (SQUID) to two different high-{Tc} thin-film flux transformers. The SQUID was made from Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8+y} films grown on MgO, with junctions consisting of native grain boundaries. The flux transformers were made from YBa{sub 2}Cu{sub 3}O{sub 7-x}, and each had 10-turn input coils and a single-turn pickup loop. The first transformer, which was patterned with a combination of shadow masks and photolithography, yielded a magnetic field gain of about {minus}7.5, functioned up to 79 K, and gave a magnetic field sensitivity B{sub N} (10 Hz) {approx} 3.1 pT Hz{sup {minus}1/2}at 38 K. The second transformer, which was patterned entirely by photolithography, yielded a gain of about {minus}8.7, functioned up to 25 K, and had a sensitivity B{sub N} (10 Hz) {approx} 3.5 pT Hz{sup {minus}1/2} at 4.2 K. In both cases, the limiting noise arose in the SQUID. 10 refs., 5 figs., 1 tab.

  4. Global maps of ground magnetometer data

    NASA Astrophysics Data System (ADS)

    Waters, C. L.; Gjerloev, J. W.; Dupont, M.; Barnes, R. J.

    2015-11-01

    A statistical-based method combined with basis function expansion techniques is described in order to provide extensive maps of the ground level perturbation magnetic field from 40∘ magnetic latitude to the north magnetic pole for all longitudes. The method combines historical data from the SuperMAG data base, Principal Component Analysis, and a spherical cap harmonic basis function expansion in order to fill in magnetic perturbation data where there are no magnetometers and produce the poloidal current potential. The maps have a regular grid with a 2∘ latitude and 1 h longitude spacing. The statistical process uses SuperMAG data derived magnetic indices plus the solar zenith angle which orders the resulting spatial maps by geomagnetic activity indicators to enhance model agreement with the data. For quiet through to moderate magnetic activity intervals, the root-mean-square error between the input and the fitted data are 18 nT and 10 nT for the north-south and east-west components, respectively, which are of similar magnitude to the statistical uncertainty in the SuperMAG data set.

  5. Plasmonic fiber-optic vector magnetometer

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaochuan; Guo, Tuan; Zhang, Xuejun; Xu, Jian; Xie, Wenping; Nie, Ming; Wu, Qiang; Guan, Bai-Ou; Albert, Jacques

    2016-03-01

    A compact fiber-optic vector magnetometer based on directional scattering between polarized plasmon waves and ferro-magnetic nanoparticles is demonstrated. The sensor configuration reported in this work uses a short section of tilted fiber Bragg grating (TFBG) coated with a nanometer scale gold film and packaged with a magnetic fluid (Fe3O4) inside a capillary. The transmission spectrum of the sensor provides a fine comb of narrowband resonances that overlap with a broader absorption of the surface plasmon resonance (SPR). The wavelength of the SPR attenuation in transmission shows high sensitivity to slight perturbations by magnetic fields, due to the strong directional scattering between the SPR attenuated cladding modes and the magnetic fluid near the fiber surface. Both the orientation (2 nm/deg) and the intensity (1.8 nm/mT) of magnetic fields can be determined unambiguously from the TFBG spectrum. Temperature cross sensitivity can be referenced out by monitoring the wavelength of the core mode resonance simultaneously.

  6. Ultrasensitive Magnetometer using a Single Atom.

    PubMed

    Baumgart, I; Cai, J-M; Retzker, A; Plenio, M B; Wunderlich, Ch

    2016-06-17

    Precision sensing, and in particular high precision magnetometry, is a central goal of research into quantum technologies. For magnetometers, often trade-offs exist between sensitivity, spatial resolution, and frequency range. The precision, and thus the sensitivity of magnetometry, scales as 1/sqrt[T_{2}] with the phase coherence time T_{2} of the sensing system playing the role of a key determinant. Adapting a dynamical decoupling scheme that allows for extending T_{2} by orders of magnitude and merging it with a magnetic sensing protocol, we achieve a measurement sensitivity even for high frequency fields close to the standard quantum limit. Using a single atomic ion as a sensor, we experimentally attain a sensitivity of 4.6  pT/sqrt[Hz] for an alternating-current magnetic field near 14 MHz. Based on the principle demonstrated here, this unprecedented sensitivity combined with spatial resolution in the nanometer range and tunability from direct current to the gigahertz range could be used for magnetic imaging in as of yet inaccessible parameter regimes. PMID:27367376

  7. The Search-Coil Magnetometer for MMS

    NASA Astrophysics Data System (ADS)

    Le Contel, O.; Leroy, P.; Roux, A.; Coillot, C.; Alison, D.; Bouabdellah, A.; Mirioni, L.; Meslier, L.; Galic, A.; Vassal, M. C.; Torbert, R. B.; Needell, J.; Rau, D.; Dors, I.; Ergun, R. E.; Westfall, J.; Summers, D.; Wallace, J.; Magnes, W.; Valavanoglou, A.; Olsson, G.; Chutter, M.; Macri, J.; Myers, S.; Turco, S.; Nolin, J.; Bodet, D.; Rowe, K.; Tanguy, M.; de la Porte, B.

    2016-03-01

    The tri-axial search-coil magnetometer (SCM) belongs to the FIELDS instrumentation suite on the Magnetospheric Multiscale (MMS) mission (Torbert et al. in Space Sci. Rev. (2014), this issue). It provides the three magnetic components of the waves from 1 Hz to 6 kHz in particular in the key regions of the Earth's magnetosphere namely the subsolar region and the magnetotail. Magnetospheric plasmas being collisionless, such a measurement is crucial as the electromagnetic waves are thought to provide a way to ensure the conversion from magnetic to thermal and kinetic energies allowing local or global reconfigurations of the Earth's magnetic field. The analog waveforms provided by the SCM are digitized and processed inside the digital signal processor (DSP), within the Central Electronics Box (CEB), together with the electric field data provided by the spin-plane double probe (SDP) and the axial double probe (ADP). On-board calibration signal provided by DSP allows the verification of the SCM transfer function once per orbit. Magnetic waveforms and on-board spectra computed by DSP are available at different time resolution depending on the selected mode. The SCM design is described in details as well as the different steps of the ground and in-flight calibrations.

  8. Calibrating the Prominence Magnetometer (ProMag)

    NASA Astrophysics Data System (ADS)

    Fox, Lewis; Casini, R.

    2013-07-01

    The Prominence Magnetometer (ProMag) is a dual-channel, dual-beam, slit-scanning, full Stokes spectro-polarimeter designed by the High Altitude Observatory at the National Center for Atmospheric Research (HAO/NCAR) for the study of the magnetism of solar prominences and filaments. It was deployed in August 2009 at the 40 cm coronagraph of the Evans Solar Facility (ESF) of the National Solar Observatory on Sacramento Peak (NSO/SP). In its standard mode of operation it acquires spectro-polarimetric maps of solar targets simultaneously in the two chromospheric lines of He I at 587.6 nm and 1083.0 nm. Since August 2011 ProMag has operated in “patrol mode” with a dedicated observer. We aim to routinely measure the vector magnetic field in prominences. The electro-optic modulator and polarization analyzer are integrated into a single mechanical unit located at the coude feed of the telescope. This location was necessary for proper co-alignment of the dual beams, but complicates the precise polarimeter calibration necessary to achieve the sensitivity required for prominence measurements (< 10^-3). At this sensitivity, small variations in optical alignment can become significant. We present a calibration method for ProMag, using a polarizer and retarder at coronagraph prime focus. Calibrations are recorded before and after observations. We discuss the success of this method and its limitations.

  9. Ultrasensitive Magnetometer using a Single Atom

    NASA Astrophysics Data System (ADS)

    Baumgart, I.; Cai, J.-M.; Retzker, A.; Plenio, M. B.; Wunderlich, Ch.

    2016-06-01

    Precision sensing, and in particular high precision magnetometry, is a central goal of research into quantum technologies. For magnetometers, often trade-offs exist between sensitivity, spatial resolution, and frequency range. The precision, and thus the sensitivity of magnetometry, scales as 1 /√{T2 } with the phase coherence time T2 of the sensing system playing the role of a key determinant. Adapting a dynamical decoupling scheme that allows for extending T2 by orders of magnitude and merging it with a magnetic sensing protocol, we achieve a measurement sensitivity even for high frequency fields close to the standard quantum limit. Using a single atomic ion as a sensor, we experimentally attain a sensitivity of 4.6 pT /√{Hz } for an alternating-current magnetic field near 14 MHz. Based on the principle demonstrated here, this unprecedented sensitivity combined with spatial resolution in the nanometer range and tunability from direct current to the gigahertz range could be used for magnetic imaging in as of yet inaccessible parameter regimes.

  10. Automated Tow Placement Processing and Characterization of Composites

    NASA Technical Reports Server (NTRS)

    Prabhakaran, R.

    2004-01-01

    The project had one of the initial objectives as automated tow placement (ATP), in which a robot was used to place a collimated band of pre-impregnated ribbons or a wide preconsolidated tape onto a tool surface. It was proposed to utilize the Automated Tow Placement machine that was already available and to fabricate carbon fiber reinforced PEEK (polyether-ether-ketone) matrix composites. After initial experiments with the fabrication of flat plates, composite cylinders were to be fabricated. Specimens from the fabricated parts were to be tested for mechanical characterization. A second objective was to conduct various types of tests for characterizing composite specimens cured by different fabrication processes.

  11. Drag Characteristics of Several Towed Decelerator Models at Mach 3

    NASA Technical Reports Server (NTRS)

    Miserentino, Robert; Bohon, Herman L.

    1970-01-01

    An investigation has been made to determine the possibility of using toroid-membrane and wide-angle conical shapes as towed decelerators. Parameter variations were investigated which might render toroid-membrane models and wide-angle- cone models stable without loss of the high drag coefficients obtainable with sting-mounted models. The parameters varied included location of center of gravity, location of the pivot between the towline and the model, and configuration modifications of the aft end as the addition of a corner radius and the addition of a skirt. The toroid membrane can be made into a stable towed decelerator with a suitable configuration modification of the aft end.

  12. Detection of J-coupling using atomic magnetometer

    DOEpatents

    Ledbetter, Micah P.; Crawford, Charles W.; Wemmer, David E.; Pines, Alexander; Knappe, Svenja; Kitching, John; Budker, Dmitry

    2015-09-22

    An embodiment of a method of detecting a J-coupling includes providing a polarized analyte adjacent to a vapor cell of an atomic magnetometer; and measuring one or more J-coupling parameters using the atomic magnetometer. According to an embodiment, measuring the one or more J-coupling parameters includes detecting a magnetic field created by the polarized analyte as the magnetic field evolves under a J-coupling interaction.

  13. Magnetometer with miniature transducer and automatic transducer scanning apparatus

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    Magnetometer is simple to operate and has fast response. Transducer is rugged and flat and can measure magnetic fields as close as 0.08 mm from any relatively flat surface. Magnetometer has active region of approximately 0.64 by 0.76 mm and is capable of good spatial resolution of magnetic fields as low as 0.02 Oe (1.6 A/m).

  14. Multichannel optical atomic magnetometer operating in unshielded environment

    NASA Astrophysics Data System (ADS)

    Bevilacqua, Giuseppe; Biancalana, Valerio; Chessa, Piero; Dancheva, Yordanka

    2016-04-01

    A multichannel atomic magnetometer operating in an unshielded environment is described and characterised. The magnetometer is based on D_1 optical pumping and D_2 polarimetry of Cs vapour contained in gas-buffered cells. Several technical implementations are described and discussed in detail. The demonstrated sensitivity of the set-up is 100 fT/√{Hz} when operating in the difference mode.

  15. Ultra-sensitive Magnetic Microscopy with an Atomic Magnetometer

    SciTech Connect

    Kim, Young Jin

    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.

  16. Air-floating towing behaviors of multi-bucket foundation platform

    NASA Astrophysics Data System (ADS)

    Le, Cong-huan; Ding, Hong-yan; Zhang, Pu-yang

    2013-10-01

    Air-floating towing behaviors of multi-bucket foundation platform (MBFP) are investigated with the 1/20-scale model tests and hydrodynamic software MOSES. MOSES numerical model was validated by test results, and MOSES prototype model of MBFP can eliminate scale effect of model. The influences of towing factors of towing speed, water depth, freeboard, and wave direction on air-floating towing stability of MBFP were analyzed by model tests and validated MOSES prototype model. It is shown that the reduction of towing speed can effectively decrease the towing force and surge acceleration to improve towing stability. Water depth is another factor in towing stability. Obvious shallow water effect will appear in shallow water with small water depth-draft ratio and it will disappear gradually and air-floating towing becomes more stable with the increase of water depth. Accelerations of surge, sway and heave are small and they have modest changes when freeboard increases from 0.5 to 2 m. For MBFP, the freeboard is not suggested to be larger than 2 m in following wave. Wave direction has large influence on the towing stability, the surge acceleration and towing force are sensitive to the variation of wave direction, the surge acceleration and towing force in following wave (0°) and counter wave (180°) are much larger than that in transverse sea (90° and 270°).

  17. 46 CFR 15.610 - Master and mate (pilot) of towing vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Master and mate (pilot) of towing vessels. 15.610... MANNING REQUIREMENTS Manning Requirements; Uninspected Vessels § 15.610 Master and mate (pilot) of towing... of a person holding a license or MMC officer endorsement as master or mate (pilot) of towing...

  18. 46 CFR 11.466 - Requirements for national endorsements as apprentice mate (steersman) of towing vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... mate (steersman) of towing vessels. 11.466 Section 11.466 Shipping COAST GUARD, DEPARTMENT OF HOMELAND... apprentice mate (steersman) of towing vessels. (a) As Table 1 to § 11.466(a) shows, to obtain an endorsement as apprentice mate (steersman) of towing vessels listed in column 1, endorsed with a route listed...

  19. 46 CFR 11.465 - Requirements for endorsements as mate (pilot) of towing vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 CFR 11.429 and 11.456, then you may obtain an endorsement as mate (pilot) of towing vessels by... 46 Shipping 1 2012-10-01 2012-10-01 false Requirements for endorsements as mate (pilot) of towing....465 Requirements for endorsements as mate (pilot) of towing vessels. (a) If you would like to...

  20. 46 CFR 11.465 - Requirements for endorsements as mate (pilot) of towing vessels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 CFR 11.429 and 11.456, then you may obtain an endorsement as mate (pilot) of towing vessels by... 46 Shipping 1 2011-10-01 2011-10-01 false Requirements for endorsements as mate (pilot) of towing....465 Requirements for endorsements as mate (pilot) of towing vessels. (a) If you would like to...

  1. 46 CFR 11.465 - Requirements for endorsements as mate (pilot) of towing vessels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 CFR 11.429 and 11.456, then you may obtain an endorsement as mate (pilot) of towing vessels by... 46 Shipping 1 2013-10-01 2013-10-01 false Requirements for endorsements as mate (pilot) of towing....465 Requirements for endorsements as mate (pilot) of towing vessels. (a) If you would like to...

  2. 33 CFR 164.78 - Navigation under way: Towing vessels.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Navigation under way: Towing vessels. 164.78 Section 164.78 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.78 Navigation under...

  3. 33 CFR 164.78 - Navigation under way: Towing vessels.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Navigation under way: Towing vessels. 164.78 Section 164.78 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.78 Navigation under...

  4. 33 CFR 164.78 - Navigation under way: Towing vessels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Navigation under way: Towing vessels. 164.78 Section 164.78 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.78 Navigation under...

  5. 33 CFR 164.78 - Navigation under way: Towing vessels.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Navigation under way: Towing vessels. 164.78 Section 164.78 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.78 Navigation under...

  6. TOWING TANK STUDIES OF STRATIFIED FLOW OVER RIDGES AND VALLEYS

    EPA Science Inventory

    Stable atmospheric flow over a ridge and a valley was simulated in a large towing tank filled with stratified salt water. Flow visualization experiments were conducted using colored dye streamers and 10 cm high models with sinusoidal cross-sections. These experiments provided qua...

  7. Imperfection Insensitivity Analyses of Advanced Composite Tow-Steered Shells

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey; Farrokh, Babak; Stanford, Bret K.; Weaver, Paul M.

    2016-01-01

    Two advanced composite tow-steered shells, one with tow overlaps and another without overlaps, were previously designed, fabricated and tested in end compression, both without cutouts, and with small and large cutouts. In each case, good agreement was observed between experimental buckling loads and supporting linear bifurcation buckling analyses. However, previous buckling tests and analyses have shown historically poor correlation, perhaps due to the presence of geometric imperfections that serve as failure initiators. For the tow-steered shells, their circumferential variation in axial stiffness may have suppressed this sensitivity to imperfections, leading to the agreement noted between tests and analyses. To investigate this further, a numerical investigation was performed in this study using geometric imperfections measured from both shells. Finite element models of both shells were analyzed first without, and then, with measured imperfections that were then, superposed in different orientations around the shell longitudinal axis. Small variations in both the axial prebuckling stiffness and global buckling load were observed for the range of imperfections studied here, which suggests that the tow steering, and resulting circumferentially varying axial stiffness, may result in the test-analysis correlation observed for these shells.

  8. 20. VIEW TO WEST OF INTERIOR OF CRANEWAY WITH TOW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. VIEW TO WEST OF INTERIOR OF CRANEWAY WITH TOW TRAVELING BRIDGE CRANES (ONE OVERHEAD IN FOREGROUND AND ONE OVERHEAD IN BACKGROUNDS). NOTE WOOD BLOCK PAVING ON THE FLOOR. FIRST FLOOR ASSEMBLY AREA IS THE SPACE IN THE BACKGROUND ON THE RIGHT. - Rosie the Riveter National Historical Park, Ford Assembly Plant, 1400 Harbour Way South, Richmond, Contra Costa County, CA

  9. Full Scale Wind Tunnel and Seaplane Tow Channel

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Construction progress, aerials of East Area. L5169: Langley's seaplane towing facility (right) and the Full Scale Tunnel (left) were photographed in November of 1930. Photograph published in Winds of Change, 75th Anniversary NASA publication (page 39), by James Schultz.

  10. Field experiments on an intelligent towed vehicle ``Flying Fish``

    SciTech Connect

    Koterayama, W.; Yamaguchi, S.; Nakamura, M.

    1995-12-31

    A depth, pitch and roll controllable towed vehicle, ``Flying Fish`` is being developed to measure the ocean current, temperature, salinity, dissolved oxygen, pH, turbidity, chlorophyll and total inorganic hydrocarbon. The first field experiments on its performance were carried out in the Japan sea last summer. The motion data of the ``Flying Fish`` are compared with those of numerical simulations.

  11. 76 FR 59415 - Towing Safety Advisory Committee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-26

    ... notice of proposed rulemaking entitled ``Inspection of Towing Vessels'' (76 FR 49976; http://www.gpo.gov/fdsys/pkg/FR-2011-08-11/pdf/2011-18989.pdf ). Written comments related to this TSAC meeting must be... the January 17, 2008, issue of the Federal Register (73 FR 3316). For access to the docket to...

  12. 18. VIEW OF BALES OF CEDAR TOW (CEDAR SHAVING WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. VIEW OF BALES OF CEDAR TOW (CEDAR SHAVING WITH SAWDUST TUMBLED OUT) SOLD FOR GARDEN AND ANIMAL BEDDING, AND OTHER AGRICULTURAL USES; TUMBLER IS CYLINDRICAL MACHINE TO LEFT - Lester Shingle Mill, 1602 North Eighteenth Street, Sweet Home, Linn County, OR

  13. Recent Advances in Magnetoseismology Using Network Observations by Ground Magnetometers

    NASA Astrophysics Data System (ADS)

    Chi, P. J.; Russell, C. T.

    2011-12-01

    The rise of modern, synchronized networks of ground magnetometers in recent years has inspired and advanced research and development in magnetoseismology. Like the practice in other geophysical disciplines, magnetoseismology can infer the structure of the magnetosphere from the observations of normal-mode frequencies of the magnetic field. It can also time and locate impulsive events by measuring the signal arrival time at multiple ground stations. We highlight recent advances in using network observations by ground magnetometers for both types of magnetoseismic research. In the area of normal-mode magnetoseismology the increase in ground magnetometers has enabled ever more station pairs suitable for the gradient analysis. We demonstrate progress in automatic detection of field line resonance frequencies and the results that reveal longitudinal structure of the plasmasphere. As a relatively young research topic, travel-time magnetoseismology has shown its capability to time and locate sudden impulses and substorm onsets by using ground-based magnetometer observations. These initial successes in turn motivated detailed examination of MHD wave propagation in the magnetosphere. In the end we discuss how these magnetoseismic studies shed light on the regions in the world where future establishment of ground magnetometers is desirable.

  14. An improved RF circuit for Overhauser magnetometer excitation

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. THEMIS Ground Based Magnetometers and the Involvement of GEONS Schools

    NASA Astrophysics Data System (ADS)

    Craig, N.; Peticolas, L.; Shutkin, A.; Dearborn, D.; Pierce, D.; Odenwald, S.; Orr, L.; Gehman, W.; Dewolf, C.; Walker, A.

    2005-05-01

    The THEMIS Education and Public Outreach team selected ten ground-based magnetometer stations each located in the proximity of a rural school in traditionally under-served, under-represented communities from Alaska to Vermont. These `ground based magnetometer' observatories will assist the THEMIS Mission's five identical satellites, called probes, when they are launched in the fall of 2006. The five probes, placed in strategic locations in Earth's magnetosphere, will help to determine the onset of auroral substorms. A teacher at each of these schools is responsible for their magnetometer data and system as well as using the data with their students through lesson plans developed collaboratively with the E/PO team. The network of teachers, students, and magnetometers together with other students who participate in monitoring the geomagnetic disturbances using the web is called the Geomagnetic Event Observation Network by Students (GEONS). We will report specific contributions to the project from the Oregon, South Dakota and Michigan GEONS teachers. We have installed five magnetometers during the Fall of 2004, and will be installing the remaining five in the Spring of 2005, and have started to display the data from the first five schools on the web. We will describe the pedagogical challenges of bringing understanding of the physics behind the THEMIS science which requires some understanding of magnetic fields, charged particles, forces, motions, and energy to middle school and high school classrooms. We will also include the formative evaluation results to date.

  17. Versatile magnetometer assembly for characterizing magnetic properties of nanoparticles

    NASA Astrophysics Data System (ADS)

    Araujo, J. F. D. F.; Bruno, A. C.; Louro, S. R. W.

    2015-10-01

    We constructed a versatile magnetometer assembly for characterizing iron oxide nanoparticles. The magnetometer can be operated at room temperature or inside a cryocooler at temperatures as low as 6 K. The magnetometer's sensor can be easily exchanged and different detection electronics can be used. We tested the assembly with a non-cryogenic commercial Hall sensor and a benchtop multimeter in a four-wire resistance measurement scheme. A magnetic moment sensitivity of 8.5 × 10-8 Am2 was obtained with this configuration. To illustrate the capability of the assembly, we synthesized iron oxide nanoparticles coated with different amounts of a triblock copolymer, Pluronic F-127, and characterized their magnetic properties. We determined that the polymer coating does not affect the magnetization of the particles at room temperature and demonstrates that it is possible to estimate the average size of coating layers from measurements of the magnetic field of the sample.

  18. NQR detection of explosive simulants using RF atomic magnetometers

    NASA Astrophysics Data System (ADS)

    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.

  19. Design and Analyses of a MEMS Based Resonant Magnetometer.

    PubMed

    Ren, Dahai; Wu, Lingqi; Yan, Meizhi; Cui, Mingyang; You, Zheng; Hu, Muzhi

    2009-01-01

    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. PMID:22399981

  20. Spin-Damping in an RF atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Alem, Orang; Romalis, Michael V.; Sauer, Karen L.

    2009-05-01

    Optically pumped atomic magnetometers have demonstrated an improved sensitivity over standard tuned coils for frequencies less than 50 MHz, making these radio-frequency (RF) magnetometers attractive for low-field NMR (for example, Budker and Romalis, Nature Physics 3, April 2007). Such magnetometers are often plagued by transient effects resulting in decreased sensitivity. The decay time of these transients, or ringing, can last for milliseconds, which is particularly detrimental for rapidly decaying NMR signals. We have found that actively damping the ringing of the atomic spins can significantly reduce such dead time. This spin-damping of the atomic transients is achieved through a negative feedback mechanism in which part of the optical signal during ringing is used to apply an RF field forcing the realignment of the atomic spins with the static magnetic field. We have successfully implemented spin-damping in 100 μs and recovered our femto-Tesla signal previously obscured by the ringing.

  1. Participation in the Cluster Magnetometer Consortium for the Cluster Mission

    NASA Technical Reports Server (NTRS)

    Kivelson, Margaret

    1997-01-01

    Prof. M. G. Kivelson (UCLA) and Dr. R. C. Elphic (LANL) are Co-investigators on the Cluster Magnetometer Consortium (CMC) that provided the fluxgate magnetometers and associated mission support for the Cluster Mission. The CMC designated UCLA as the site with primary responsibility for the inter-calibration of data from the four spacecraft and the production of fully corrected data critical to achieving the mission objectives. UCLA was also charged with distributing magnetometer data to the U.S. Co-investigators. UCLA also supported the Technical Management Team, which was responsible for the detailed design of the instrument and its interface. In this final progress report we detail the progress made by the UCLA team in achieving the mission objectives.

  2. Assessing and Ensuring GOES-R Magnetometer Accuracy

    NASA Technical Reports Server (NTRS)

    Carter, Delano R.; Todirita, Monica; Kronenwetter, Jeffrey; Chu, Donald

    2016-01-01

    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. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma. 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. Both behave as expected, and their accuracy predictions agree within 30%. With the proposed calibration regimen, both suggest that the GOES-R magnetometer subsystem will meet its accuracy requirements.

  3. Rotating sample magnetometer for cryogenic temperatures and high magnetic fields

    NASA Astrophysics Data System (ADS)

    Eisterer, M.; Hengstberger, F.; Voutsinas, C. S.; Hörhager, N.; Sorta, S.; Hecher, J.; Weber, H. W.

    2011-06-01

    We report on the design and implementation of a rotating sample magnetometer (RSM) operating in the variable temperature insert (VTI) of a cryostat equipped with a high-field magnet. The limited space and the cryogenic temperatures impose the most critical design parameters: the small bore size of the magnet requires a very compact pick-up coil system and the low temperatures demand a very careful design of the bearings. Despite these difficulties the RSM achieves excellent resolution at high magnetic field sweep rates, exceeding that of a typical vibrating sample magnetometer by about a factor of ten. In addition the gas-flow cryostat and the high-field superconducting magnet provide a temperature and magnetic field range unprecedented for this type of magnetometer.

  4. Performances of compact integrated superconducting magnetometers for biomagnetic imaging

    NASA Astrophysics Data System (ADS)

    Granata, C.; Vettoliere, A.; Rombetto, S.; Nappi, C.; Russo, M.

    2008-10-01

    In the present paper, performances of compact fully integrated superconducting quantum interference device (SQUID) magnetometers, recently developed, have been investigated in view of their employment in large multichannel systems for biomagnetic imaging. The analysis has been focused on SQUID sensors having a pickup loop side length of 3 and 4 mm based on a design aimed to maximize the magnetic flux transferred from the detection coil to the SQUID in comparison with a magnetometer with 9 mm side length having a suitable sensitivity for biomagnetic applications. The performance study has been consisted in the computation of the magnetic responses to a current dipole which is the most fundamental approach used in biomagnetism. The results have shown that the dipole current sensitivity of 4 mm long side compact magnetometers is suitable for application in multichannel systems for magnetoencephalography and magnetocardiography.

  5. Magnetometer with a miniature transducer and automatic scanning

    NASA Technical Reports Server (NTRS)

    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. Assessing and ensuring GOES-R magnetometer accuracy

    NASA Astrophysics Data System (ADS)

    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.

  7. Electron Paramagnetic Resonance -- Nuclear Magnetic Resonance Three Axis Vector Magnetometer

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Larsen, Michael; Mirijanian, James

    2012-06-01

    The Northrop Grumman Corporation is leveraging the technology developed for the Nuclear Magnetic Resonance Gyroscope (NMRG) to build a combined Electron Paramagnetic Resonance -- Nuclear Magnetic Resonance (EPR-NMR) magnetometer. The EPR-NMR approach provides a high bandwidth and high sensitivity simultaneous measurement of all three vector components of the magnetic field averaged over the small volume of the sensor's one vapor cell. This poster will describe the history, operational principles, and design basics of the EPR-NMR magnetometer including an overview of the NSD designs developed and demonstrated to date. General performance results will also be presented.

  8. Heisenberg-scaled magnetometer with dipolar spin-1 condensates

    NASA Astrophysics Data System (ADS)

    Xing, Haijun; Wang, Anbang; Tan, Qing-Shou; Zhang, Wenxian; Yi, Su

    2016-04-01

    We propose a scheme to realize a Heisenberg-scaled magnetometer using dipolar spin-1 condensates. The input state of magnetometer is prepared by slowly sweeping a transverse magnetic field to zero, which yields a highly entangled spin state of N atoms. We show that this process is protected by a parity symmetry such that the state preparation time is within the reach of the current experiment. We also propose a parity measurement with a Stern-Gerlach apparatus which is shown to approach the optimal measurement in the large atom number limit. Finally, we show that the phase estimation sensitivity of the proposed scheme roughly follows the Heisenberg scaling.

  9. Lunar physical properties from analysis of magnetometer data

    NASA Technical Reports Server (NTRS)

    Daily, W. D.

    1979-01-01

    The electromagnetic properties of the lunar interior are discussed with emphasis on (1) bulk, crustal, and local anomalous conductivity; (2) bulk magnetic permeability measurements, iron abundance estimates, and core size limits; (3) lunar ionosphere and atmosphere; and (4) crustal magnetic remanence: scale size measurements and constraints on remanence origin. Appendices treat the phase relationship between the energetic particle flux modulation and current disc penetrations in the Jovian magnetosphere (Pioneer 10 inbound) theories for the origin of lunar magnetism; electrical conductivity anomalies associated with circular lunar maria; electromagnetic properties of the Moon; Mare Serenitatis conductivity anomaly detected by Apollo 16 and Lunokhod 2 magnetometers; and lunar properties from magnetometer data: effects of data errors.

  10. Three-axis atomic magnetometer based on spin precession modulation

    SciTech Connect

    Huang, H. C.; Dong, H. F. Hu, X. Y.; Chen, L.; Gao, Y.

    2015-11-02

    We demonstrate a three-axis atomic magnetometer with one intensity-modulated pump beam and one orthogonal probe beam. The main field component is measured using the resonance of the pumping light, while the transverse field components are measured simultaneously using the optical rotation of the probe beam modulated by the spin precession. It is an all-optical magnetometer without using any modulation field or radio frequency field. Magnetic field sensitivity of 0.8 pT/Hz{sup 1∕2} is achieved under a bias field of 2 μT.

  11. A high-sensitivity push-pull magnetometer

    SciTech Connect

    Breschi, E.; Grujić, Z. D.; Knowles, P.; Weis, A.

    2014-01-13

    We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/√(Hz), using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/√(Hz)

  12. A low-power, high-sensitivity micromachined optical magnetometer

    NASA Astrophysics Data System (ADS)

    Mhaskar, R.; Knappe, S.; Kitching, J.

    2012-12-01

    We demonstrate an optical magnetometer based on a microfabricated 87Rb vapor cell in a micromachined silicon sensor head. The alkali atom density in the vapor cell is increased by heating the cell with light brought to the sensor through an optical fiber, and absorbed by colored filters attached to the cell windows. A second fiber-optically coupled beam optically pumps and interrogates the atoms. The magnetometer operates on 140 mW of heating power and achieves a sensitivity below 20 fT/√Hz throughout most of the frequency band from 15 Hz to 100 Hz. Such a sensor can measure magnetic fields from the human heart and brain.

  13. Thermomechanical Characterization of SiC Fiber Tows and Implications for CMC

    NASA Technical Reports Server (NTRS)

    Yun, H. M.; DiCarlo, J. A.

    1999-01-01

    In order to better understand SiC fiber behavior within CMC microstructures, mechanical tests were performed on multifilament tows consisting of different types of as produced and pretreated fibers. Tensile strengths of tows and single fibers were measured at room temperature for nonstoichiometric Hi-Nicalon and ZMI fibers and for stoichiometric Hi-Nicalon-S, Tyranno SA. and Sylramic fibers. Based on simple bundle theory, measured strengths for as-produced and sized tows were in general agreement with the single fiber results. However, after sizing removal under inert conditions, tow strengths for the coarser grained stoichiometric fibers were typically lower than those predicted from individual fiber data. This effect is attributed to enhanced fiber-fiber mechanical interaction caused by sizing removal from the rough surfaces of these fibers. In support of this, tow strengths remained high for those fiber types with fine grains or excess surface carbon; and, when re-coated with a BN interphase coating, tow strengths for the coarser grained fibers returned to their as-produced values. When the tows were pretreated in air at intermediate temperatures, tow strengths decreased in a manner that could be correlated with the oxidation characteristics of each fiber type as measured by thermogravimetric analysis. The creep and rupture properties of Hi-Nicalon and Sylramic tows were also measured in air and argon from 1200 to 1400 C. Although displaying transient and environmental effects similar to single fibers, the tows crept faster at short times and slower at long times. This resulted in the tow rupture strengths at long time being much greater than the rupture strengths of single fibers. The CMC implications of the tow results are discussed, as well as the benefits and limitations of tow testing.

  14. A towed airborne platform for turbulence measurements over the ocean

    NASA Astrophysics Data System (ADS)

    Friehe, Carl; Khelif, Djamal

    2008-11-01

    Measurements of wind stress and associated heat and mass fluxes (water vapor and CO2) down to ˜10 meters height over the ocean are required to establish parameterizations for wave, weather, hurricane and climate models. At high winds and accompanying sea states, such measurements are difficult or impossible. A new airborne instrumented towed platform has been developed that allows measurements down to 10 meters under radar-altitude control while the tow aircraft is safely above. Measurements include the three components of the wind, temperature, humidity, infrared surface temperature, CO2, and motion and navigational parameters. The bandwidth of the sensors allows calculation of the Reynolds averaged covariance's of stress and sensible heat and evaporation fluxes. Results are compared to equivalent measurements made with an instrumented aircraft. We would like to thank Robert Bluth of the Naval Postgraduate School and Jesse Barge and Dan Bierly of Zivko Aeronautics.

  15. Optimizing an undulating magnetic microswimmer for cargo towing

    NASA Astrophysics Data System (ADS)

    Gutman, Emiliya; Or, Yizhar

    2016-06-01

    One of the promising capabilities of magnetic microswimmers is towing a cargo, which can be used for targeted drug delivery or performing tissue biopsy. A key question is what should be the optimal size ratio between the cargo and the swimmer's flexible tail. This question is addressed here for the simplest theoretical model of a magnetic microswimmer undergoing planar undulations—a spherical load connected by a torsion spring to a rigid slender link. The swimmer's dynamic is formulated and leading-order expressions for its motion are obtained explicitly under small-amplitude approximation. Optimal combinations of magnetic actuation frequency, torsion stiffness, and tail length for maximizing displacement, average speed, or energetic efficiency are obtained. The theoretical results are compared with reported experiments in several types of cargo-towing magnetic microswimmers.

  16. Powder-Curtain Feeder For Coating Filament Tow

    NASA Technical Reports Server (NTRS)

    Baucom, Robert M.; Snoha, John J.; Marchello, Joseph M.

    1994-01-01

    Continuous fiber web receives powder coat first on one side, then on other. Vibrating helical screw mechanism in powder feeder provides even flow of powder to form powder curtain that descends onto moving web. Small amount of powder that falls to side or through web recovered easily. Powder-curtain feeder part of apparatus similar to one described in "System Applies Polymer Powder to Filament Tow" (LAR-14231).

  17. Paresev 1-A on lakebed with tow plane

    NASA Technical Reports Server (NTRS)

    1962-01-01

    The Paresev 1-A (Paraglider Research Vehicle) and the tow airplane, 450-hp Stearman sport Biplane, sitting on Rogers dry lakebed, Edwards, California. The control system in the Paresev 1-A had a more conventional control stick position and was cable-operated; the main landing gear used shocks and bungees with the 150-square-foot wing membrane being made of 6-ounce unsealed Dacron.

  18. Paresev 1-A on Lakebed with Tow Plane

    NASA Technical Reports Server (NTRS)

    1962-01-01

    The Paresev 1-A (Paraglider Research Vehicle) and the tow airplane, 450-hp Stearman Sport Biplane sitting on Rogers dry lakebed, Edwards, California. The control system in the Paresev 1-A had a more conventional control stick position and was cable-operated. The main landing gear used shocks and bungees with the 150-square-foot wing membrane being made of 6-ounce unsealed Dacron.

  19. Evaluation of a Highly Anticlastic Panel with Tow Overlaps

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey; Gurdal, Zafer

    2007-01-01

    A rectangular, variable-stiffness panel with tow overlaps was manufactured using an advanced tow placement machine. The cured panel had large anticlastic imperfections, with measured amplitudes of over two times the average panel thickness. These imperfections were not due to the overall steered-fiber layup or the tow overlaps, but instead resulted from local asymmetries in the laminate that were caused by a manufacturing oversight. In the nominal panel layup, fiber angles vary linearly from 60 degrees on the panel axial centerline to 30 degrees on the parallel edges. A geometrically nonlinear analysis was performed with a -280 degree Fahrenheit thermal load to simulate the postcure cooldown to room temperature. The predicted geometric imperfections correlated well with the measured panel shape. Unique structural test fixtures were then developed which greatly reduced these imperfections, but they also caused prestresses in the panel. Surface imperfections measured after the panel was installed in the test fixtures were used with nonlinear finite element analyses to predict these fixturing-induced prestresses. These prestresses were also included in structural analyses of panel end compression to failure, and the analytical results compared well with test data when both geometric and material nonlinearities were included.

  20. Hybrid IR-Gas Heater for Automated Tow Placement

    NASA Technical Reports Server (NTRS)

    Grenoble, Ray W.; Johnston, Norman J.; Tiwari, S. N.; Marchello, Joseph M.

    1998-01-01

    A hybrid infrared-hot gas heat source has been developed and tested for the NASA Langley Tow Placement Facility. The IR heat source provides supplemental heat to the nip region. The additional heat is intended to reduce the need for conduction heating by the compaction roller, which causes (he roller to stick to the panel surface. Initial bench scale testing was performed to identify the most effective means of focusing IR energy into the nip region. A compact lamp and reflector that placed the lamp as close to the nip point as possible was found to deliver the highest heat flux in the nip region. A prototype heater was installed on the NASA Langley tow placement robot. Panels placed with a 400 C (sticking) compaction roller gave DCB initiation toughness numbers comparable to those reported for autoclave processed panels but were found to have unexpectedly high void contents. Placement with compaction roller temperatures that prevented roller sticking resulted in mode I fracture toughness approximately 70% that reported for autoclave processed panels. The variability in strength among specimens placed with reduced roller temperature was found to be greatly reduced, which implies that use of supplemental nip point heat may improve the robustness of the tow placement process. Use of the IR heat source permitted placement with a compaction roller temperature that would have resulted in negligible interfacial strength with the hot gas torch alone. The roller temperature reductions eliminated the need for the robot operator to attend placement operations.

  1. Optimizing an undulating magnetic microswimmer for cargo towing

    NASA Astrophysics Data System (ADS)

    Or, Yizhar; Gutman, Emiliya

    2015-11-01

    One of the promising applications of robotic microswimmers is towing a cargo for controlled drug delivery, micro-surgery or tumor detection. This capability has been demonstrated by the magnetically-actuated microswimmer of Dreyfus et al. [Nature 2005] in which a red blood cell was attached to a chain of magnetic beads connected by flexible DNA links. A key question is what should be the optimal size of the magnetic tail for towing a given cargo. This question is addressed here for the simplest theoretical model of a magnetic microswimmer under planar undulations - a spherical load connected by a torsion spring to a magnetized rigid slender link. The swimmer's dynamics is formulated assuming negligible hydrodynamic interaction and leading-order expressions for the resulting motion are obtained explicitly under small amplitude approximation. Optimal combinations of magnetic actuation frequency, torsion stiffness, and tail length for maximizing displacement or average speed are obtained. The theoretical results are compared with several reported magnetic microswimmers, and also agree qualitatively with recent results on cargo towing by screw rotation of magnetic helical tails [Walker et al., ACS Nano Letters 2015]. This work is supported by the Israeli Science Foundation (ISF) under Grant No. 567/14.

  2. Surface Towed CSEM Systems for Shallow Water Mapping

    NASA Astrophysics Data System (ADS)

    Sherman, J.; Constable, S.; Kannberg, P. K.

    2015-12-01

    We have developed a low-power, surface towed electric dipole-dipole system suitable for mapping seafloor geology in shallow water and deployable from small boats. The transmitter is capable of up to 50 amps output using 12 VDC from a 110/240 VAC power supply, and can generate an arbitrary GPS stabilized ternary waveform. Transmitter antennas are typically 50 to 100 m long. Receivers are built around the standard Scripps seafloor electrode, amplifier, and logging systems but housed in floating PVC cases and equipped with GPS timing and positioning, pitch/roll/heading sensors, and accelerometers. Receiver dipoles are 1.5 m long rigid booms held 1 m below the surface. As with the Scripps deep-towed Vulcan system, rigid antennas are used to avoid noise associated with flexible antennas moving across Earth's magnetic field. The tow cable is a simple floating rope up to 1000 m long. Water depth and conductivity are sampled continuously in order to provide constraints for apparent resistivity calculations and inversion, and moored seafloor recorders can be used to extend transmitter/receiver offsets. The entire system can be air freighted and transported in one utility vehicle. We will present results from a study to map permafrost in shallow water off Prudhoe Bay, Alaska.

  3. M2-F1 in hangar with Pontiac tow vehicle

    NASA Technical Reports Server (NTRS)

    1963-01-01

    The M2-F1 Lifting Body is seen here in a hangar with its hotrod Pontiac convertible tow vehicle at the Flight Research Center (later the Dryden Flight Research Center), Edwards, California. The car was a 1963 Pontiac Catalina convertible, fitted with a 421-cubic-inch tripower engine like those being run at the Daytona 500 auto race. The vehicle also had a four-speed transmission and a heavy-duty suspension and cooling system. A roll bar was also added and the passenger seat turned around so an observer could watch the M2-F1 while it was being towed. The rear seat was removed and a second, side-facing seat installed. The lifting-body team used the Pontiac for all the ground-tow flights over the next three years. The wingless, lifting body aircraft design was initially conceived as a means of landing an aircraft horizontally after atmospheric reentry. The absence of wings would make the extreme heat of re-entry less damaging to the vehicle. In 1962, Dryden management approved a program to build a lightweight, unpowered lifting body as a prototype to flight test the wingless concept. It would look like a 'flying bathtub,' and was designated the M2-F1, the 'M' referring to 'manned' and 'F' referring to 'flight' version. It featured a plywood shell placed over a tubular steel frame crafted at Dryden. Construction was completed in 1963. The first flight tests of the M2-F1 were over Rogers Dry Lake at the end of a tow rope attached to a hopped-up Pontiac convertible driven at speeds up to about 120 mph. This vehicle needed to be able to tow the M2-F1 on the Rogers Dry Lakebed adjacent to NASA's Flight Research Center (FRC) at a minimum speed of 100 miles per hour. To do that, it had to handle the 400-pound pull of the M2-F1. Walter 'Whitey' Whiteside, who was a retired Air Force maintenance officer working in the FRC's Flight Operations Division, was a dirt-bike rider and hot-rodder. Together with Boyden 'Bud' Bearce in the Procurement and Supply Branch of the FRC, Whitey

  4. Small fluxgate magnetometers: development and future trends in Spain.

    PubMed

    Ciudad, David; Díaz-Michelena, Marina; Pérez, Lucas; Aroca, Claudio

    2010-01-01

    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. PMID:22294904

  5. A new algorithm for attitude-independent magnetometer calibration

    NASA Technical Reports Server (NTRS)

    Alonso, Roberto; Shuster, Malcolm D.

    1994-01-01

    A new algorithm is developed for inflight magnetometer bias determination without knowledge of the attitude. This algorithm combines the fast convergence of a heuristic algorithm currently in use with the correct treatment of the statistics and without discarding data. The algorithm performance is examined using simulated data and compared with previous algorithms.

  6. Sensor noise in low-level flux-gate magnetometers.

    NASA Technical Reports Server (NTRS)

    Scouten, D. C.

    1972-01-01

    The noise mechanism in a well-designed magnetometer is shown to be due to small-scale magnetic moments which are probably small volumes of the core material that are not oriented by the drive field. Design developments include the sense coil radius and the development of a drive waveform which yields considerably improved performance over the commonly used sine wave drive.

  7. Determining Future Epicenters by Triangulation of Magnetometer Pulses in Peru

    NASA Astrophysics Data System (ADS)

    Heraud, J. A.; Centa, V. A.; Bleier, T.; Dunson, C.

    2013-12-01

    The direction of arrival of magnetometer pulses have been observed in several cases and in several stations since April 2010 in Tacna, Peru. The azimuth can be obtained from the three-axis magnetometers but only a direction to the possible epicenter could be deduced and not the distance or location was really possible. Three earthquakes, Ml 4.1, 3.8, 4.8, that occurred on April 4, April 12 and June 18, 2013 respectively in Central Peru, were preceded by pulses, observed in magnetometer records between 10 and 18 days before the onset of the earthquakes. This time, three axis magnetometers in two stations situated 55 km apart and about 25-35 km from the future epicenter were ready to receive the pulses simultaneously. The azimuths were computed for both stations and the triangulation of simultaneous pulses rendered the position of possible release points of p-holes during several days, in approximately the two-week period until the onset of the earthquakes. The observations have been post, however the data has been analyzed and plotted in a sequential way, showing the sequence of events from the first pulses until the occurrence of the earthquakes, giving coincidental positions with the possible rupture zone for the seismic events. The animated videos obtained of these events will be shown.

  8. Magnetometer Based on the Opto-Electronic Oscillator

    NASA Technical Reports Server (NTRS)

    Matsko, Andrey B.; Strekalov, Dmitry; Maleki, Lute

    2005-01-01

    We theoretically propose and discuss properties of two schemes of an all-optical self-oscillating magnetometer based on an opto-electronic oscillator stabilized with an atomic vapor cell. Proof of the principle DC magnetic field measurements characterized with 2 x 10(exp -7) G sensitivity and 1 - 1000 mG dynamic range in one of the schemes are demonstrated.

  9. The Pioneer 11 high-field fluxgate magnetometer

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.; Ness, N. F.

    1973-01-01

    The High Field Fluxgate Magnetometer Experiment flow aboard the Pioneer 11 spacecraft to investigate Jupiter's magnetic field is described. The instrument extends the spacecraft's upper limit measurement capability by more than an order of magnitude to 17.3 gauss with minimum power and volume requirements.

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

    PubMed Central

    Ciudad, David; Díaz-Michelena, Marina; Pérez, Lucas; Aroca, Claudio

    2010-01-01

    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. PMID:22294904

  11. Astronaut Alan Bean deploys Lunar Surface Magnetometer on lunar surface

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Astronaut Alan L. Bean, lunar module pilot, deploys the Lunar Surface Magnetometer (LSM) during the first Apollo 12 extravehicular activity on the Moon. The LSM is a component of the Apollo Lunar Surface Experiments Package (ALSEP). The Lunar Module can be seen in the left background.

  12. Real-Time Attitude Independent Three Axis Magnetometer Calibration

    NASA Technical Reports Server (NTRS)

    Crassidis, John L.; Lai, Kok-Lam; Harman, Richard R.

    2003-01-01

    In this paper new real-time approaches for three-axis magnetometer sensor calibration are derived. These approaches rely on a conversion of the magnetometer-body and geomagnetic-reference vectors into an attitude independent observation by using scalar checking. The goal of the full calibration problem involves the determination of the magnetometer bias vector, scale factors and non-orthogonality corrections. Although the actual solution to this full calibration problem involves the minimization of a quartic loss function, the problem can be converted into a quadratic loss function by a centering approximation. This leads to a simple batch linear least squares solution. In this paper we develop alternative real-time algorithms based on both the extended Kalman filter and Unscented filter. With these real-time algorithms, a full magnetometer calibration can now be performed on-orbit during typical spacecraft mission-mode operations. Simulation results indicate that both algorithms provide accurate integer resolution in real time, but the Unscented filter is more robust to large initial condition errors than the extended Kalman filter. The algorithms are also tested using actual data from the Transition Region and Coronal Explorer (TRACE).

  13. Early Results from the IMI-30 Towed Sonar System

    NASA Astrophysics Data System (ADS)

    Edwards, M. H.; Rognstad, M. R.; Tottori, S. N.; Davis, R. B.; Appelgate, T. B.; Johnson, P. D.; Kevis-Stirling, A.

    2006-12-01

    The Hawaii Mapping Research Group (HMRG) of the University of Hawaii has designed and built a 30 kHz deep-towed sonar, the IMI-30, which simultaneously collects interferometric bathymetry and backscatter data. The sonar is capable of being deployed to 6000 m water depth, where it is towed 100-500 m above the seafloor yielding a total swath width of 1-5 km for sidescan and somewhat less than that for bathymetry. The across-track resolution is <10 m for bathymetry depending on towing geometry and substrate type, and 0.3- 3 m for sidescan, depending on the selected transmit pulse length and tow vehicle altitude. The along-track resolution, which is dependent on vehicle speed and pulse repetition rate, varies between 0.6 and 3 meters. Here we report on data collected by the system during two different deployments in the Pacific: the IMI-30's initial field program in the Lau Basin in 2004 and the most recent survey using the system, south of Oahu in June of 2006. Between the 2004 Lau program and the June 2006 survey, several engineering improvements were made including: 1) changing the housings of the side-looking transducers from cast polyurethane to oil- filled polyethylene; 2) adding syntactic foam baffling to reduce surface bounce; 3) synchronizing sound velocimeter measurements with sonar transmit; 4) adding sub-bottom transducers and associated electronics to the tow vehicle; 5) adding two additional side-looking transducer rows per side, and 6) upgrading the surface and subsurface power supplies. This engineering effort has improved reliability of the system by eliminating transducer failures caused by seawater leakage and power supply over-temperature shutdown in tropical waters. Reducing the system noise - electrical, hydrodynamic, and acoustic - has improved data quality and extended the swath width. The addition of sub-bottom data acquisition further increases the utility of the IMI-30 system. Our presentation will document the engineering effort and

  14. Full Scale Tunnel (FST) and Seaplane Tow Channel

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Installation of Careystone covering at the Full-Scale Tunnel (FST) facility. The corrugated concrete and asbestos panels (1/4 inch thick; 42 inches wide; 62 inches long) which were used as siding and roofing for the Full-Scale Tunnel were manufactured by The Philip Carey Company. For the NACA, the choice of Careystone had been based on several factors. First and foremost was its low cost. NACA engineers had observed the very durable, low-maintenance and fireproof qualities of the concrete-asbestos covering of the airship hanger at Langley Field. Further, tests showed the material to be 3.8 times stronger than required (The maximum load the material was expected to withstand was 52 lbs. per square foot; the breaking load was 196 lbs. per sq. ft.). L4695 shows the interior view of construction of the Tow Tank. In the late 1920s, the NACA decided to investigate the aero/hydro dynamics of floats for seaplanes. A Hydrodynamics Branch was established in 1929 and special towing basin was authorized in March of that same year. Starr Truscott (the first head of the new division) described the tank in NACA TR 470: 'The N.A.C.A. tank is of the Froude type; that is, the model which is being tested is towed through still water at successive constant speeds from a carriage spanning the tank. At each constant speed the towing pull is measured, the trim and the rise, or change of draft, are recorded and, if the model is being towed at a fixed trim, the moment required to hold it there is measured and recorded.' 'The reinforced concrete basin containing the water has the following dimensions: (1) Length on water, extreme, 2,020 feet; (2) Normal width of water surface, 24 feet; (3) Normal depth of water, 12 feet; (4) Length of 12 foot depth, 1,980 feet.' This picture shows the tank before the coving was added. This brought the rails for the carriage closer together and helped suppress waves produced by the models. The finished tank would be filled with approximately 4 million

  15. Method and apparatus for deregistering multi-filament tow and product thereof

    DOEpatents

    Lukhard, Craig R.; Potter, Jerry F.; Todd, Maurice C.

    1995-01-01

    A method and apparatus for deregistering drawn crimped nylon multifilament tow includes the steps of stretching the tow under constant controlled tension at a temperature below the glass transition temperature of the nylon. The apparatus includes means for sensing the tension of the tow between the feed and draw sections of a stretching device and producing a signal representative of the tension sensed and a controller for changing the speed of the draw section actuated by said signal.

  16. Magnetic induction measurements using an all-optical {sup 87}Rb atomic magnetometer

    SciTech Connect

    Wickenbrock, Arne; Tricot, François; Renzoni, Ferruccio

    2013-12-09

    In this work we propose, and experimentally demonstrate, the use of a self-oscillating all-optical atomic magnetometer for magnetic induction measurements. Given the potential for miniaturization of atomic magnetometers, and their extreme sensitivity, the present work shows that atomic magnetometers may play a key role in the development of instrumentation for magnetic induction tomography.

  17. Prince William Sound disabled tanker towing study. Part 1. Evaluation of existing equipment, personnel and procedures

    SciTech Connect

    Not Available

    1993-08-01

    The study has been undertaken by the Glosten Associates, Inc., to evaluate the existing capability for emergency towing at Prince William Sound and to examine alternatives that could enhance the escort and assist capabilities for disabled tankers within the waterway from the Alyeska Oil Terminal at the Port of Valdez to the Gulf of Alaska outside Hinchinbrook Entrance. Part 1, reported herein, is an objective evaluation by an experienced salvage towing master of the existing tugs, emergency towing equipment, towing practices, and discussion of alternative tug types.

  18. Engineered Polymer Composites Through Electrospun Nanofiber Coating of Fiber Tows

    NASA Technical Reports Server (NTRS)

    Kohlman, Lee W.; Bakis, Charles; Williams, Tiffany S.; Johnston, James C.; Kuczmarski, Maria A.; Roberts, Gary D.

    2014-01-01

    Composite materials offer significant weight savings in many aerospace applications. The toughness of the interface of fibers crossing at different angles often determines failure of composite components. A method for toughening the interface in fabric and filament wound components using directly electrospun thermoplastic nanofiber on carbon fiber tow is presented. The method was first demonstrated with limited trials, and then was scaled up to a continuous lab scale process. Filament wound tubes were fabricated and tested using unmodified baseline towpreg material and nanofiber coated towpreg.

  19. Temperature Effects on the Features of the CHAMP Vector Magnetometer

    NASA Astrophysics Data System (ADS)

    Yin, Fan; Ma, Shuying; Luehr, Hermann; Rauberg, Jan

    2015-04-01

    CHAMP (CHAllenging Minisatellite Payload), a German small satellite mission to study the Earth's gravity field, magnetic field and upper atmosphere, ended in space on 19 September 2010. Thanks to the good quality of the satellite and to several altitude maneuvers, the satellite provided continuous and reliable observations including house-keeping data at different processing levels for more than 10 years. By processing the data of FGM (FluxGate vector Magnetometer), some effects of temperature on the FGM performance have been unfolded. The scale factors of the FGM show a positive correlation with the sensor temperature and the offsets show both positive and negative correlation. The 8 Hz disturbances from FGM x channel are temperature dependent and suppressed at higher temperature. It is very interesting that the noise power of the magnetometer has a larger magnitude at lower temperature rather than at higher temperature.

  20. Results from the GSFC fluxgate magnetometer on Pioneer 11

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.; Ness, N. F.

    1976-01-01

    A high-field triaxial fluxgate magnetometer was mounted on Pioneer 11 to measure the main magnetic field of Jupiter. It is found that this planetary magnetic field is more complex than that indicated by the results of the Pioneer 10 vector helium magnetometer. At distances less than 3 Jupiter radii, the magnetic field is observed to increase more rapidly than an inverse-cubed distance law associated with any simple dipole model. Contributions from higher-order multipoles are significant, with the quadrupole and octupole being 24 and 21 percent of the dipole moment, respectively. Implications of the results for the study of trapped particles, planetary radio emission, and planetary interiors are discussed. Major conclusions are that the deviation of the main planetary magnetic field from a simple dipole leads to distortion of the L shells of the charged particles and to warping of the magnetic equator. Enhanced absorption effects associated with Amalthea and Io are predicted.

  1. Space magnetometer based on an anisotropic magnetoresistive hybrid sensor

    NASA Astrophysics Data System (ADS)

    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.

  2. Performance characteristics of a three-axis superconducting rock magnetometer

    NASA Technical Reports Server (NTRS)

    Lienert, B. R.

    1977-01-01

    A series of measurements are carried out with the purpose of quantitatively determining the characteristics of a commercial 6.8 cm access superconducting rock magnetometer located in the magnetic properties laboratory at the Goddard Space Flight Center. The measurements show that although a considerable improvement in measurement speed and signal to noise ratios can be obtained using such an instrument, a number of precautions are necessary to obtain accuracies comparable with more conventional magnetometers. These include careful calibration of the sensor outputs, optimum positioning of the sample within the detection region and quantitatively establishing the degree of cross-coupling between the detector coils. In order to examine the uniformity of response for each detector, the responses are mapped as a function of position, using a small dipole.

  3. Construction of an AMR magnetometer for car detection experiments

    NASA Astrophysics Data System (ADS)

    Fúra, V.; Petrucha, V.; Platil, A.

    2016-03-01

    A new construction of magnetometer with commercially available AMR (anisotropic magnetoresistive) sensors intended for vehicle detection experiments is presented. Initial experiments with simple AMR gradiometer indicated viability of the approach in a real- world setup. For further experiments and acquisition of representative data, a new design of precise multi-channel magnetometer was developed. The design supports two models of commercial AMR sensors: the proven and reliable, but obsolete Honeywell HMC1021-series sensors and newly available Sensitec AFF755B sensors. In the comparison the two types are similar in most achieved parameters, except offset stability in flipped operation regime. Unfortunately, the new AFF755B sensors seem to have perhaps inferior coupling of the flipping (set/reset) coil to the ferromagnetic core that causes insufficient saturation of the AMR material. The issue is being solved by Sensitec, current deliverables of the AFF755B have “product sample” status (September 2015).

  4. Combined alternating gradient force magnetometer and susceptometer system

    SciTech Connect

    Pérez, M.; Mendizábal Vázquez, I. de; Aroca, C.

    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.

  5. Combined alternating gradient force magnetometer and susceptometer system.

    PubMed

    Pérez, M; Ranchal, R; de Mendizábal Vázquez, I; Cobos, P; Aroca, C

    2015-01-01

    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(-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. PMID:25638125

  6. Assessing and Ensuring GOES-R Magnetometer Accuracy

    NASA Technical Reports Server (NTRS)

    Kronenwetter, Jeffrey; Carter, Delano R.; Todirita, Monica; Chu, Donald

    2016-01-01

    The GOES-R magnetometer accuracy requirement is 1.7 nanoteslas (nT). During quiet times (100 nT), accuracy is defined as absolute mean plus 3 sigma. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma. To achieve this, the sensor itself has better than 1 nT accuracy. Because zero offset and scale factor drift over time, it is also necessary to perform annual calibration maneuvers. To predict performance, we used covariance analysis and attempted to corroborate it with simulations. Although not perfect, the two generally agree and show the expected behaviors. With the annual calibration regimen, these predictions suggest that the magnetometers will meet their accuracy requirements.

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

    PubMed

    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. PMID:25554336

  8. On-chip magnetometer for characterization of superparamagnetic nanoparticles.

    PubMed

    Kim, Kun Woo; Reddy, Venu; Torati, Sri Ramulu; Hu, Xing Hao; Sandhu, Adarsh; Kim, Cheol Gi

    2015-02-01

    An on-chip magnetometer was fabricated by integrating a planar Hall magnetoresistive (PHR) sensor with microfluidic channels. The measured in-plane field sensitivities of an integrated PHR sensor with NiFe/Cu/IrMn trilayer structure were extremely high at 8.5 μV Oe(-1). The PHR signals were monitored during the oscillation of 35 pL droplets of magnetic nanoparticles, and reversed profiles for the positive and negative z-fields were measured, where magnitudes increased with the applied z-field strength. The measured PHR signals for 35 pL droplets of magnetic nanoparticles versus applied z-fields showed excellent agreement with magnetization curves measured by a vibrating sample magnetometer (VSM) of 3 μL volume, where a PHR voltage of 1 μV change is equivalent to 0.309 emu cc(-1) of the volume magnetization with a magnetic moment resolution of ~10(-10) emu. PMID:25474348

  9. Development of NMOR magnetometer for spin-maser EDM experiment

    NASA Astrophysics Data System (ADS)

    Yoshimi, A.; Nanao, T.; Inoue, T.; Furukawa, T.; Uchida, M.; Tsuchiya, M.; Hayashi, H.; Chikamori, M.; Asahi, K.

    We have been developing a high sensitivity atomic magnetometer for atomic EDM experiments using a lowfrequency nuclear spin maser. In the developed nuclear spin maser of 129Xe, suppression of drift and fluctuation in the magnetic field is one of the important issues. The magnetometer being developed for spin maser EDM experiments utilizes the nonlinear magneto optical rotation (NMOR) e_ect in Rb atomic vapor. The enhancement of the optical rotation in a small magnetic field relies on the long spin-coherence time of Rb atoms in a vapor cell. The NMOR spectrum was measured by using fabricated Rb cells coated with an anti-relaxation material. The NMOR spectrum dependence on laser frequency, cell coating, and laser beam diameter were investigated. The magnetic sensitivity at present is 0:2 μG/√Hz from observed NMOR and noise spectra.

  10. MOURA Martian magnetometer potential for high resolution magnetic mapping

    NASA Astrophysics Data System (ADS)

    Díaz-Michelena, Marina; Kilian, Rolf

    2013-04-01

    Mars Global Surveyor (MGS) mission mapped the magnetic signature all along the Martian globe during its operation between 1996 and 2006. These data shows that Mars does not present an active global magnetic field as the Earth. However, the Martian crust has an overall magnetic signature stronger than the Earth which was inherited from the active magnetic field of the Martian core during its early cooling history. The MGS survey shows plenty of magnetic anomalies located in particular within high lands of its Southern Hemisphere. Several magnetic models have been derived to explain the MGS data considering magnetic dipoles distribution in the Martian crust with moderate to high magnetic intensities and pronounced regional anomalies. However, the origin of major magnetic anomalies remains highly disputed [1]. From the magnetic investigation point of view it would be of major importance to perform near-surface magnetic measurements [2] to compare both surface and in orbit (between 100 and 440 km) data. This would help to comprehend not only the distribution of the magnetic dipoles but also to make progress in the identification of different rock types and understanding of their degree of alteration which could have modified superficial magnetic signatures. In the frame of Finnish-Russian and Spanish MetNet mission, to perform meteorological studies on Martian surface, a miniaturized magnetometer and gradiometer named MOURA was developed with the objective to improve the interpretation of the magnetic anomalies and their origin. In order to test this magnetometer, comparative on Earth magnetic measurements were performed with MOURA and a reference absolute scalar magnetometer (Geometrics 853) in areas with a representative and large variation of magmatic rocks compositions. The final goal is to test the appropriateness of the developed magnetometer for the in situ measurements on Mars. The active continental margin of the Patagonian Andes was used for this case study

  11. A High Sensitivity Laser-Pumped Cesium Magnetometer

    NASA Astrophysics Data System (ADS)

    Huang, Kai-Kai; Li, Nan; Lu, Xuan-Hui

    2012-10-01

    An atomic magnetometer based on optically detected magnetic resonance is investigated and demonstrated experimentally. We build an 894 nm external cavity diode laser which is frequency locked to the F = 4 → F' = 3 transition of Cs D1 line with DAVLL spectroscopy. With the phase-locked loop, the frequency of the rf coils is actively locked to the Larmor frequency and the magnetometer tracks the magnetic field variations in a phase coherent manner. An ultimate sensitivity of 19 fT/Hz1/2 and an intrinsic sensitivity of 8.6 pT/Hz1/2 in the magnetic environment which is close to geomagnetic field have been achieved with the spatial resolution smaller than 2 cm.

  12. Attitude and Trajectory Determination using Magnetometers and Estimated Rates

    NASA Technical Reports Server (NTRS)

    Schierman, J. D.; Schmidt, D. K.; Deutschmann, J.

    1997-01-01

    A simultaneous attitude and orbit determination algorithm which uses magnetometer measurements and estimated attitude rates is presented. This is an extension of an algorithm which uses magnetometer and rate gyro measurements. The new algorithm is intended for gyroless spacecraft, or in the case of gyro failures/saturation. Torque control input data is used in forming the rate estimates. Simulation tests of the algorithm are presented. First, tests were performed using the 'true' rate values at each time step. This simulated using accurate gyro measurements. Then, tests were performed estimating the rates. Using estimated rates rather than 'gyro measurements' did not significantly degrade the algorithm's performance if accurate estimates of the initial rates were available. An initial Root-Sum-Square (RSS) position error of 1,400 km was reduced to an average error of approximately 100 km within the first two minutes. The RSS attitude error converged to less than 1.5 degrees within three orbits.

  13. Data Acquisition System for Russian Arctic Magnetometer Network

    NASA Astrophysics Data System (ADS)

    Janzhura, A.; Troshichev, O. A.; Takahashi, K.

    2010-12-01

    Monitoring of magnetic activity in the auroral zone is very essential for space weather problem. The big part of northern auroral zone lies in the Russian sector of Arctica. The Russian auroral zone stations are located far from the proper infrastructure and communications, and getting the data from the stations is complicated and nontrivial task. To resolve this problem a new acquisition system for magnetometers was implemented and developed in last few years, with the magnetic data transmission in real time that is important for many forecasting purpose. The system, based on microprocessor modules, is very reliable in hush climatic conditions. The information from the magnetic sensors transmits to AARI data center by satellite communication system and is presented at AARI web pages. This equipment upgrading of Russian polar magnetometer network is supported by the international RapidMag program.

  14. Versatile magnetometer assembly for characterizing magnetic properties of nanoparticles

    SciTech Connect

    Araujo, J. F. D. F.; Bruno, A. C.; Louro, S. R. W.

    2015-10-15

    We constructed a versatile magnetometer assembly for characterizing iron oxide nanoparticles. The magnetometer can be operated at room temperature or inside a cryocooler at temperatures as low as 6 K. The magnetometer’s sensor can be easily exchanged and different detection electronics can be used. We tested the assembly with a non-cryogenic commercial Hall sensor and a benchtop multimeter in a four-wire resistance measurement scheme. A magnetic moment sensitivity of 8.5 × 10{sup −8} Am{sup 2} was obtained with this configuration. To illustrate the capability of the assembly, we synthesized iron oxide nanoparticles coated with different amounts of a triblock copolymer, Pluronic F-127, and characterized their magnetic properties. We determined that the polymer coating does not affect the magnetization of the particles at room temperature and demonstrates that it is possible to estimate the average size of coating layers from measurements of the magnetic field of the sample.

  15. 33 CFR 164.76 - Towline and terminal gear for towing alongside and pushing ahead.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Towline and terminal gear for towing alongside and pushing ahead. 164.76 Section 164.76 Navigation and Navigable Waters COAST GUARD... Towline and terminal gear for towing alongside and pushing ahead. The owner, master, or operator of...

  16. 46 CFR 27.100 - What towing vessels does this part affect?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... defined by 46 CFR 10.103; (iv) For response to emergency or pollution; (2) A public vessel that is both... General Provisions for Fire-Protection Measures and Fire-Suppression Equipment on Towing Vessels § 27.100...; or (4) Exempted by the Captain of the Port (COTP). (c) If you think your towing vessel should...

  17. 33 CFR 164.74 - Towline and terminal gear for towing astern.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Towline and terminal gear for towing astern. 164.74 Section 164.74 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.74 Towline and terminal gear for towing astern. (a) Towline....

  18. 33 CFR 164.74 - Towline and terminal gear for towing astern.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Towline and terminal gear for towing astern. 164.74 Section 164.74 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.74 Towline and terminal gear for towing astern. (a) Towline....

  19. 49 CFR 393.71 - Coupling devices and towing methods, driveaway-towaway operations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Act, 49 U.S.C. 1655, and the delegations of authority at 49 CFR 1.48 and 389.4) Effective Date Note... requirements: (1) Tow-bars, structural adequacy and mounting. Every tow-bar shall be structurally adequate and.... Such means shall not depend upon either the looseness or deformation of the parts of either the...

  20. 49 CFR 393.71 - Coupling devices and towing methods, driveaway-towaway operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Act, 49 U.S.C. 1655, and the delegations of authority at 49 CFR 1.48 and 389.4) ... the following requirements: (1) Tow-bars, structural adequacy and mounting. Every tow-bar shall be.... Such means shall not depend upon either the looseness or deformation of the parts of either the...

  1. 46 CFR 27.205 - What are the requirements for internal communication systems on towing vessels?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... reliable method of voice communication, with a main or reserve power supply that is independent of the electrical system on your towing vessel; and (2) Provides two-way voice communication and calling between the... requirements for internal communication systems on towing vessels? (a) You must ensure that your vessel...

  2. 46 CFR 27.205 - What are the requirements for internal communication systems on towing vessels?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... reliable method of voice communication, with a main or reserve power supply that is independent of the electrical system on your towing vessel; and (2) Provides two-way voice communication and calling between the... requirements for internal communication systems on towing vessels? (a) You must ensure that your vessel...

  3. 46 CFR 27.205 - What are the requirements for internal communication systems on towing vessels?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... reliable method of voice communication, with a main or reserve power supply that is independent of the electrical system on your towing vessel; and (2) Provides two-way voice communication and calling between the... requirements for internal communication systems on towing vessels? (a) You must ensure that your vessel...

  4. 46 CFR 27.205 - What are the requirements for internal communication systems on towing vessels?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... reliable method of voice communication, with a main or reserve power supply that is independent of the electrical system on your towing vessel; and (2) Provides two-way voice communication and calling between the... requirements for internal communication systems on towing vessels? (a) You must ensure that your vessel...

  5. 46 CFR 11.464 - Requirements for endorsements as master of towing vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... master of towing vessels if before May 21, 2004, you complete the examination required by 46 CFR 10.903(a... Endorsement as Master of Towing Vessels 1 Route endorsed Total service 2 TOS 3 on T/V as mate (pilot) TOS 3 on T/V as mate (pilot) not as harbor assist TOS 3 onparticular route Subordinate route authorized 1 2...

  6. 46 CFR 11.464 - Requirements for endorsements as master of towing vessels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... master of towing vessels if before May 21, 2004, you complete the examination required by 46 CFR 10.903(a... Endorsement as Master of Towing Vessels 1 Route endorsed Total service 2 TOS 3 on T/V as mate (pilot) TOS 3 on T/V as mate (pilot) not as harbor assist TOS 3 onparticular route Subordinate routeauthorized 1 2...

  7. 46 CFR 15.610 - Master and mate (pilot) of towing vessels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Master and mate (pilot) of towing vessels. 15.610... MANNING REQUIREMENTS Manning Requirements; Uninspected Vessels § 15.610 Master and mate (pilot) of towing... and control of a person holding a license or MMC officer endorsement as master or mate (pilot)...

  8. 46 CFR 15.610 - Master and mate (pilot) of towing vessels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Master and mate (pilot) of towing vessels. 15.610... MANNING REQUIREMENTS Manning Requirements; Uninspected Vessels § 15.610 Master and mate (pilot) of towing... and control of a person holding a license or MMC officer endorsement as master or mate (pilot)...

  9. 46 CFR 15.610 - Master and mate (pilot) of towing vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Master and mate (pilot) of towing vessels. 15.610... MANNING REQUIREMENTS Manning Requirements; Uninspected Vessels § 15.610 Master and mate (pilot) of towing... and control of a person holding a license or MMC officer endorsement as master or mate (pilot)...

  10. 46 CFR 11.464 - Requirements for endorsements as master of towing vessels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... master of towing vessels if before May 21, 2004, you complete the examination required by 46 CFR 10.903(a... Endorsement as Master of Towing Vessels 1 Route endorsed Total service 2 TOS 3 on T/V as mate (pilot) TOS 3 on T/V as mate (pilot) not as harbor assist TOS 3 onparticular route Subordinate route authorized 1 2...

  11. 46 CFR 11.465 - Requirements for national endorsements as mate (pilot) of towing vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Requirements for national endorsements as mate (pilot... National Deck Officer Endorsements § 11.465 Requirements for national endorsements as mate (pilot) of towing vessels. (a) To obtain an endorsement as mate (pilot) of towing vessels endorsed with a...

  12. 46 CFR 11.464 - Requirements for national endorsements as master of towing vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Totalservice 2 TOS 3 on T/V as mate (pilot) TOS 3 onparticular route Sub-ordinateroute authorized (1) OCEANS (O... endorsement placed on the MMC as mate (pilot) of towing vessels for a route superior to the current route on... and remove the endorsement for mate (pilot) of towing vessels. 2 Service is in months. 3 TOS is...

  13. 33 CFR 164.74 - Towline and terminal gear for towing astern.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Towline and terminal gear for towing astern. 164.74 Section 164.74 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS § 164.74 Towline and terminal gear for towing astern. (a) Towline....

  14. Theory of double resonance magnetometers based on atomic alignment

    SciTech Connect

    Weis, Antoine; Bison, Georg; Pazgalev, Anatoly S.

    2006-09-15

    We present a theoretical study of the spectra produced by optical-radio-frequency double resonance devices, in which resonant linearly polarized light is used in the optical pumping and detection processes. We extend previous work by presenting algebraic results which are valid for atomic states with arbitrary angular momenta, arbitrary rf intensities, and arbitrary geometries. The only restriction made is the assumption of low light intensity. The results are discussed in view of their use in optical magnetometers.

  15. Using Redundancy To Reduce Errors in Magnetometer Readings

    NASA Technical Reports Server (NTRS)

    Kulikov, Igor; Zak, Michail

    2004-01-01

    A method of reducing errors in noisy magnetic-field measurements involves exploitation of redundancy in the readings of multiple magnetometers in a cluster. By "redundancy"is meant that the readings are not entirely independent of each other because the relationships among the magnetic-field components that one seeks to measure are governed by the fundamental laws of electromagnetism as expressed by Maxwell's equations. Assuming that the magnetometers are located outside a magnetic material, that the magnetic field is steady or quasi-steady, and that there are no electric currents flowing in or near the magnetometers, the applicable Maxwell 's equations are delta x B = 0 and delta(raised dot) B = 0, where B is the magnetic-flux-density vector. By suitable algebraic manipulation, these equations can be shown to impose three independent constraints on the values of the components of B at the various magnetometer positions. In general, the problem of reducing the errors in noisy measurements is one of finding a set of corrected values that minimize an error function. In the present method, the error function is formulated as (1) the sum of squares of the differences between the corrected and noisy measurement values plus (2) a sum of three terms, each comprising the product of a Lagrange multiplier and one of the three constraints. The partial derivatives of the error function with respect to the corrected magnetic-field component values and the Lagrange multipliers are set equal to zero, leading to a set of equations that can be put into matrix.vector form. The matrix can be inverted to solve for a vector that comprises the corrected magnetic-field component values and the Lagrange multipliers.

  16. Search for plant biomagnetism with a sensitive atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Corsini, Eric; Acosta, Victor; Baddour, Nicolas; Higbie, James; Lester, Brian; Licht, Paul; Patton, Brian; Prouty, Mark; Budker, Dmitry

    2011-04-01

    We report what we believe is the first experimental limit placed on plant biomagnetism. Measurements with a sensitive atomic magnetometer were performed on the Titan arum (Amorphophallus titanum) inflorescence, known for its fast biochemical processes while blooming. We find that the magnetic field from these processes, projected along the Earth's magnetic field, and measured at the surface of the plant, is ≲ 0.6 μG.

  17. J-MAG: Magnetometer science on the JUICE mission

    NASA Astrophysics Data System (ADS)

    Dougherty, Michele

    2014-05-01

    The magnetometer instrument onboard JUICE is one of the core instruments on the payload and is critical for resolving some of the prime science objectives of the mission. The primary science objectives of JUICE which will be constrained by the magnetic field observations will be described. They include characterising ocean properties at Ganymede, Callisto and Europa, resolving the dynamo magnetic field at Ganymede as well as better understanding magnetospheric dynamics.

  18. A computer control system for the alternating gradient magnetometer

    NASA Technical Reports Server (NTRS)

    Garland, Michael M.

    1989-01-01

    An alternating gradient magnetometer was interfaced to a computer for the automation of data taking. Using a fast Fourier transform analysis system data can be acquired and processed in real time. Data are stored on disk and can be recalled for plotting and further analysis. With the addition of a simple liquid nitrogen cryostat, magnetization measurements can be performed in the range from 300 to 77 K. Results are reported on three different types of piezoelectric transducers.

  19. Elimination of flux-transformer crosstalk in multichannel SQUID magnetometers

    NASA Astrophysics Data System (ADS)

    ter Brake, H. J. M.; Fleuren, F. H.; Ulfrnan, J. A.; Flokstra, J.

    Multichannel SQUID magnetometers are being developed for signal-field mapping in biomagnetic experiments. A problem that becomes more serious as the number of channels is increased is the crosstalk caused by the mutual inductances between the individual sensing coils. A simple and effective method for eliminating this crosstalk is presented in this Paper. The method is based on a rearrangement of the feedback loops which causes the flux-transformer circuits to become currentless. The feasibility of the method is verified experimentally.

  20. In-Flight Calibration Processes for the MMS Fluxgate Magnetometers

    NASA Astrophysics Data System (ADS)

    Bromund, K. R.; Leinweber, H. K.; Plaschke, F.; Strangeway, R. J.; Magnes, W.; Fischer, D.; Nakamura, R.; Anderson, B. J.; Russell, C. T.; Baumjohann, W.; Chutter, M.; Torbert, R. B.; Le, G.; Slavin, J. A.; Kepko, L.

    2015-12-01

    The calibration effort for the Magnetospheric Multiscale Mission (MMS) Analog Fluxgate (AFG) and Digital Fluxgate (DFG) magnetometers is a coordinated effort between three primary institutions: University of California, Los Angeles (UCLA); Space Research Institute, Graz, Austria (IWF); and Goddard Space Flight Center (GSFC). Since the successful deployment of all 8 magnetometers on 17 March 2015, the effort to confirm and update the ground calibrations has been underway during the MMS commissioning phase. The in-flight calibration processes evaluate twelve parameters that determine the alignment, orthogonalization, offsets, and gains for all 8 magnetometers using algorithms originally developed by UCLA and the Technical University of Braunschweig and tailored to MMS by IWF, UCLA, and GSFC. We focus on the processes run at GSFC to determine the eight parameters associated with spin tones and harmonics. We will also discuss the processing flow and interchange of parameters between GSFC, IWF, and UCLA. IWF determines the low range spin axis offsets using the Electron Drift Instrument (EDI). UCLA determines the absolute gains and sensor azimuth orientation using Earth field comparisons. We evaluate the performance achieved for MMS and give examples of the quality of the resulting calibrations.

  1. AC Circuit Measurements with a Differential Hall Element Magnetometer

    NASA Astrophysics Data System (ADS)

    Calkins, Matthew W.; Nicks, B. Scott; Quintero, Pedro A.; Meisel, Mark W.

    2013-03-01

    As the biomedical field grows, there is an increasing need to quickly and efficiently characterize more samples at room temperature. An automated magnetometer was commissioned to do these room temperature magnetic characterizations. This magnetometer, which is inspired by a Differential Hall Element Magnetometer,[2] uses two commercially available Hall elements wired in series. One Hall element measures the external magnetic field of a 9 T superconducting magnet and the other measures the same external field plus the field due to the magnetization of the sample that sits on top of the Hall element. The difference between these two Hall elements is taken while a linear stepper motor sweeps through the external magnetic field. The linear motor and data acquisition are controlled by a LabVIEW program. Recently, the system was outfitted for AC circuit measurements and these data will be compared to DC circuit data. In addition, the lowest signal to noise ratio will be found in order to deduce the smallest amount of sample needed to register an accurate coercive field. Supported by the NSF via NHMFL REU (DMR-0654118), a single investigator grant (DMR-1202033 to MWM) and by the UF Undergraduate Scholars Program.

  2. Particle swarm optimization algorithm based low cost magnetometer calibration

    NASA Astrophysics Data System (ADS)

    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

  3. In-Flight Calibration Processes for the MMS Fluxgate Magnetometers

    NASA Technical Reports Server (NTRS)

    Bromund, K. R.; Leinweber, H. K.; Plaschke, F.; Strangeway, R. J.; Magnes, W.; Fischer, D.; Nakamura, R.; Anderson, B. J.; Russell, C. T.; Baumjohann, W.; Chutter, M.; Torbert, R. B.; Le, G.; Slavin, J. A.; Kepko, E. L.

    2015-01-01

    The calibration effort for the Magnetospheric Multiscale Mission (MMS) Analog Fluxgate (AFG) and DigitalFluxgate (DFG) magnetometers is a coordinated effort between three primary institutions: University of California, LosAngeles (UCLA); Space Research Institute, Graz, Austria (IWF); and Goddard Space Flight Center (GSFC). Since thesuccessful deployment of all 8 magnetometers on 17 March 2015, the effort to confirm and update the groundcalibrations has been underway during the MMS commissioning phase. The in-flight calibration processes evaluatetwelve parameters that determine the alignment, orthogonalization, offsets, and gains for all 8 magnetometers usingalgorithms originally developed by UCLA and the Technical University of Braunschweig and tailored to MMS by IWF,UCLA, and GSFC. We focus on the processes run at GSFC to determine the eight parameters associated with spin tonesand harmonics. We will also discuss the processing flow and interchange of parameters between GSFC, IWF, and UCLA.IWF determines the low range spin axis offsets using the Electron Drift Instrument (EDI). UCLA determines the absolutegains and sensor azimuth orientation using Earth field comparisons. We evaluate the performance achieved for MMS andgive examples of the quality of the resulting calibrations.

  4. Polarization enhanced Nuclear Quadrupole Resonance with an atomic magnetometer

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    Ali, Abdelrahman; Siddharth, Siddharth; Syed, Zainab; El-Sheimy, Naser

    2012-01-01

    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.

  6. GPS/Magnetometer Based Satellite Navigation and Attitude Determination

    NASA Technical Reports Server (NTRS)

    Deutschmann, Julie; Bar-Itzhack, Itzhack; Harman, Rick; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    In recent years algorithms were developed for orbit, attitude and angular-rate determination of Low Earth Orbiting (LEO) satellites. Those algorithms rely on measurements of magnetometers, which are standard, relatively inexpensive, sensors that are normally installed on every LEO satellite. Although magnetometers alone are sufficient for obtaining the desired information, the convergence of the algorithms to the correct values of the satellite orbital parameters, position, attitude and angular velocity is very slow. The addition of sun sensors reduces the convergence time considerably. However, for many LEO satellites the sun data is not available during portions of the orbit when the spacecraft (SC) is in the earth shadow. It is here where the GPS space vehicles (SV) can provide valuable support. This is clearly demonstrated in the present paper. Although GPS measurements alone can be used to obtain SC position, velocity, attitude and angular-rate, the use of magnetometers improve the results due to the synergistic effect of sensor fusion. Moreover, it is possible to obtain these results with less than three SVs. In this paper we introduce an estimation algorithm, which is a combination of an Extended Kalman Filter (EKF) and a Pseudo Linear Kalman Filter (PSELIKA).

  7. Nonlinear analysis of the ground-based magnetometer network

    NASA Astrophysics Data System (ADS)

    DiTommaso, Joseph Henry

    When the first magnetometer was created by Frederick Gauss in 1833, scientists gained a powerful tool for studying the structure, dynamics, and strength of the Earth's magnetic field: the magnetosphere. Since Gauss' time, the world's scientific community has established ground-based magnetometer stations around the globe in an effort to study local and global perturbations and patterns of the Earth's magnetic field. The main focus of this network has been monitoring the magnetic flux and impact from the Sun's constant outflow of radiation and particles known as the solar wind, as well as its more violent eruptive events. There has been little work, by comparison, into the signals and correlations within the network itself. Since the Earth's field can roughly be mapped to a dipole and disturbances often have a large scale structure, one can surmise there should be some correlation between stations based on their relative positions to one another. What that correlation is or represents is not clear. To investigate this possible correlation and its nature, a set of nonlinear analytic methods were conducted on magnetic data collected from stations scattered across North America over an 18 year period. The analysis was focused on searching for spatial and temporal correlations of nonperiodic signals in the magnetometer network. The findings from that analysis suggest there exist nonlocal correlations between stations that are dependent on position, which could be useful in the development of a space weather risk assessment.

  8. Results of the Magnetometer Navigation (MAGNAV)lnflight Experiment

    NASA Technical Reports Server (NTRS)

    Thienel, Julie K.; Harman, Richard R.; Bar-Itzhack, Itzhack Y.; Lambertson, Mike

    2004-01-01

    The Magnetometer Navigation (MAGNAV) algorithm is currently running as a flight experiment as part of the Wide Field Infrared Explorer (WIRE) Post-Science Engineering Testbed. Initialization of MAGNAV occurred on September 4, 2003. MAGNAV is designed to autonomously estimate the spacecraft orbit, attitude, and rate using magnetometer and sun sensor data. Since the Earth's magnetic field is a function of time and position, and since time is known quite precisely, the differences between the computed magnetic field and measured magnetic field components, as measured by the magnetometer throughout the entire spacecraft orbit, are a function of the spacecraft trajectory and attitude errors. Therefore, these errors are used to estimate both trajectory and attitude. In addition, the time rate of change of the magnetic field vector is used to estimate the spacecraft rotation rate. The estimation of the attitude and trajectory is augmented with the rate estimation into an Extended Kalman filter blended with a pseudo-linear Kalman filter. Sun sensor data is also used to improve the accuracy and observability of the attitude and rate estimates. This test serves to validate MAGNAV as a single low cost navigation system which utilizes reliable, flight qualified sensors. MAGNAV is intended as a backup algorithm, an initialization algorithm, or possibly a prime navigation algorithm for a mission with coarse requirements. Results from the first six months of operation are presented.

  9. Calibration of SQUID vector magnetometers in full tensor gradiometry systems

    NASA Astrophysics Data System (ADS)

    Schiffler, M.; Queitsch, M.; Stolz, R.; Chwala, A.; Krech, W.; Meyer, H.-G.; Kukowski, N.

    2014-08-01

    Measurement of magnetic vector or tensor quantities, namely of field or field gradient, delivers more details of the underlying geological setting in geomagnetic prospection than a scalar measurement of a single component or of the scalar total magnetic intensity. Currently, highest measurement resolutions are achievable with superconducting quantum interference device (SQUID)-based systems. Due to technological limitations, it is necessary to suppress the parasitic magnetic field response from the SQUID gradiometer signals, which are a superposition of one tensor component and all three orthogonal magnetic field components. This in turn requires an accurate estimation of the local magnetic field. Such a measurement can itself be achieved via three additional orthogonal SQUID reference magnetometers. It is the calibration of such a SQUID reference vector magnetometer system that is the subject of this paper. A number of vector magnetometer calibration methods are described in the literature. We present two methods that we have implemented and compared, for their suitability of rapid data processing and integration into a full tensor magnetic gradiometry, SQUID-based, system. We conclude that the calibration routines must necessarily model fabrication misalignments, field offset and scale factors, and include comparison with a reference magnetic field. In order to enable fast processing on site, the software must be able to function as a stand-alone toolbox.

  10. Harmonic magnetometer baseline derivation in the ECLAT project

    NASA Astrophysics Data System (ADS)

    van de Kamp, Max

    2013-04-01

    In the EU FP7 project 'European Cluster Assimilation Technology' (ECLAT), a novel method for deriving the baselines, or 'quiet day curves', of magnetometer data has been developed. The full baseline is composed of two main components: the diurnal baseline and the long-term baseline. For the diurnal baseline, first 'templates' are derived, based on the lowest few harmonics of the daily curves from the quietest days. The diurnal variation of the baseline is obtained by interpolating between these templates. This method ensures a smooth baseline at all times, avoiding any discontinuities at transitions between days or months. The long-term baseline is obtained by interpolating between the daily median values. This way, the baseline is ensured to follow long-term trends, such as seasonal and tidal variations, as well as equipment drift. The daily median values are calculated for all days expect the most disturbed ones; a procedure is included to ensure that these median values are unaffected by disturbances. This procedure avoids many problems associated with other existing baseline procedures, and makes magnetometer data suitable for the calculation of ionospheric equivalent currents. Even data from remote unmanned magnetometers, which exhibit unrealistic equipment drift, can be made suitable this way, which can be valuable contributions to the equivalent current database.

  11. A YBCO RF-SQUID magnetometer and its applications

    NASA Technical Reports Server (NTRS)

    Luwei, Zhou; Jingwu, Qiu; Xienfeng, Zhang; Zhiming, Tank; Yongjia, Qian

    1990-01-01

    An applicable RF-superconducting quantum interference detector (SQUID) magnetometer was made using a bulk sintered yttrium barium copper oxide (YBCO). The temperature range of the magnetometer is 77 to 300 K and the field range 0 to 0.1T. At 77 K, the equivalent flux noise of the SQUID is 5 x 10 to minus 4 power theta sub o/square root of Hz at the frequency range of 20 to 200 Hz. The experiments show that the SQUID noise at low-frequency end is mainly from 1/f noise. A coil test shows that the magnetic moment sensitivity delta m is 10 to the minus 6th power emu. The RF-SQUID is shielded in a YBCO cylinder with a shielding ability B sub in/B sub ex of about 10 to the minus 6th power when external dc magnetic field is about a few Oe. The magnetometer is successfully used in characterizing superconducting thin films.

  12. A tow concept for the space shuttle orbiter approach and landing test

    NASA Technical Reports Server (NTRS)

    Bonner, T. F., Jr.; Pride, J. D., Jr.

    1976-01-01

    The tow concept provides the means for evaluating the orbiter aerodynamic performance and handling qualities in the same configuration as expected in actual space shuttle flight operation. A Boeing 747-100 aircraft has engine-out capability to tow the orbiter to an altitude that permits a safe orbiter approach and landing. The tow concept also provides a means for conducting a comprehensive ground test program before proceeding into the actual ALT flight operations. The implementation of the tow concept requires only a minor structural modification in the nose section of the orbiter vehicle; requires minor modifications in the 747 cargo bay; and makes use of those orbiter onboard systems installed in the ALT orbiter vehicle. The 747 wake turbulence does not constitute a problem for the orbiter during take-off or climb to altitude. The impact that the tow concept would have on the cost and schedule of the space shuttle program was not evaluated in this study.

  13. 49 CFR 214.525 - Towing with on-track roadway maintenance machines or hi-rail vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Towing with on-track roadway maintenance machines... SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.525 Towing with on-track roadway maintenance machines or hi-rail vehicles. (a) When used to tow pushcars or other maintenance-of-way...

  14. 49 CFR 214.525 - Towing with on-track roadway maintenance machines or hi-rail vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Towing with on-track roadway maintenance machines... SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.525 Towing with on-track roadway maintenance machines or hi-rail vehicles. (a) When used to tow pushcars or other maintenance-of-way...

  15. 49 CFR 214.525 - Towing with on-track roadway maintenance machines or hi-rail vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Towing with on-track roadway maintenance machines... SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.525 Towing with on-track roadway maintenance machines or hi-rail vehicles. (a) When used to tow pushcars or other maintenance-of-way...

  16. 49 CFR 214.525 - Towing with on-track roadway maintenance machines or hi-rail vehicles.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Towing with on-track roadway maintenance machines... SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.525 Towing with on-track roadway maintenance machines or hi-rail vehicles. (a) When used to tow pushcars or other maintenance-of-way...

  17. 49 CFR 214.525 - Towing with on-track roadway maintenance machines or hi-rail vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Towing with on-track roadway maintenance machines... SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.525 Towing with on-track roadway maintenance machines or hi-rail vehicles. (a) When used to tow pushcars or other maintenance-of-way...

  18. 46 CFR 2.01-50 - Persons other than crew on towing, oyster, or fishing steam vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Persons other than crew on towing, oyster, or fishing steam vessels. 2.01-50 Section 2.01-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing,...

  19. 46 CFR 2.01-50 - Persons other than crew on towing, oyster, or fishing steam vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Persons other than crew on towing, oyster, or fishing steam vessels. 2.01-50 Section 2.01-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing,...

  20. 46 CFR 2.01-50 - Persons other than crew on towing, oyster, or fishing steam vessels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Persons other than crew on towing, oyster, or fishing steam vessels. 2.01-50 Section 2.01-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing,...

  1. 46 CFR 2.01-50 - Persons other than crew on towing, oyster, or fishing steam vessels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Persons other than crew on towing, oyster, or fishing steam vessels. 2.01-50 Section 2.01-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing,...

  2. 46 CFR 2.01-50 - Persons other than crew on towing, oyster, or fishing steam vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Persons other than crew on towing, oyster, or fishing steam vessels. 2.01-50 Section 2.01-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES... than crew on towing, oyster, or fishing steam vessels. (a) A steam vessel engaged in towing,...

  3. 46 CFR 31.15-10 - Towing vessels may carry persons in addition to crew-B/LBR.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .../LBR. 31.15-10 Section 31.15-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS INSPECTION AND CERTIFICATION Manning of Tank Vessels § 31.15-10 Towing vessels may carry persons in addition to crew—B/LBR. (a) Towing vessels engaged in towing tank barges on the Great Lakes, inland waters,...

  4. 46 CFR 27.211 - What are the specifications for fuel systems on towing vessels whose construction was contracted...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false What are the specifications for fuel systems on towing vessels whose construction was contracted for on or after January 18, 2000? 27.211 Section 27.211 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS TOWING VESSELS Fire-Protection Measures for Towing Vessels § 27.211 What...

  5. 46 CFR 27.211 - What are the specifications for fuel systems on towing vessels whose construction was contracted...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false What are the specifications for fuel systems on towing vessels whose construction was contracted for on or after January 18, 2000? 27.211 Section 27.211 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS TOWING VESSELS Fire-Protection Measures for Towing Vessels § 27.211 What...

  6. Optimization of Elastically Tailored Tow-Placed Plates with Holes

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn C.; Tatting, Brian F.; Guerdal, Zafer

    2003-01-01

    Elastic stiffness tailoring of laminated composite panels by allowing the fibers to curve within the plane of the laminate is a design concept that has been demonstrated to be both beneficial and practical. The objective of the present paper is to demonstrate the effectiveness of stiffness tailoring through the use of curvilinear fibers to reduce stress concentrations around the hole and improve the load carrying capability of panels. Preliminary panel designs that are to be manufactured and tested were determined through design studies for flat plates without holes under axial compression using an optimization program. These candidate designs were then analyzed with finite element models that accurately reflect the test conditions and geometries in order to decide upon the final designs for manufacture and testing. An advanced tow-placement machine is used to manufacture the test panels with varying fiber orientation angles. A total of six large panels measuring three feet by six feet, each of which is used to produce four specimens with or without holes, are fabricated. The panels were machined into specimens with holes and tested at NASA Langley Research Center. Buckling response and failure of panels without holes and with two different hole dimensions are presented. Buckling and failure loads of tow-steered specimens are significantly greater than the buckling and failure loads of traditional straight-fiber specimens.

  7. F-106 tow cable attachment and release mechanism for Eclipse program

    NASA Technical Reports Server (NTRS)

    1997-01-01

    View of the tow cable attachment and release mechanism forward of the cockpit on the QF-106 Eclipse aircraft. This mechanism held and then released the Vectran rope used to tow the QF-106 behind an Air Force C-141A. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

  8. M2-F1 in flight on tow line

    NASA Technical Reports Server (NTRS)

    1964-01-01

    The M2-F1 Lifting Body is seen here under tow at the Flight Research Center (later redesignated the Dryden Flight Research Center), Edwards, California. The wingless, lifting-body aircraft design was initially concieved as a means of landing an aircraft horizontally after atmospheric reentry. The absence of wings would make the extreme heat of re-entry less damaging to the vehicle. In 1962, Flight Research Center management approved a program to build a lightweight, unpowered lifting body as a prototype to flight test the wingless concept. It would look like a 'flying bathtub,' and was designated the M2-F1, the 'M' referring to 'manned' and 'F' referring to 'flight' version. It featured a plywood shell placed over a tubular steel frame crafted at Dryden. Construction was completed in 1963. The M2-F1 project had limited goals. They were to show that a piloted lifting body could be built, that it could not only fly but be controlled in flight, and that it could make a successful landing. While the M2-F1 did prove the concept, with a wooden fuselage and fixed landing gear, it was far from an operational spacecraft. The next step in the lifting-body development was to build a heavyweight, rocket-powered vehicle that was more like an operational lifting body, albeit one without the thermal protection system that would be needed for reentry into the atmosphere from space at near-orbital speeds. The first flight tests of the M2-F1 were over Rogers Dry Lake at the end of a tow rope attached to a hopped-up Pontiac convertible driven at speeds up to about 120 mph. These initial tests produced enough flight data about the M2-F1 to proceed with flights behind a NASA C-47 tow plane at greater altitudes. The C-47 took the craft to an altitude of 12,000 where free flights back to Rogers Dry Lake began. Pilot for the first series of flights of the M2-F1 was NASA research pilot Milt Thompson. Typical glide flights with the M2-F1 lasted about two minutes and reached speeds of 110 to

  9. A very high-resolution, deep-towed, multichannel seismic streamer, part I: technical design

    NASA Astrophysics Data System (ADS)

    Bialas, J.; Breitzke, M.

    2003-04-01

    In order to allow very high resolution seismic data collection a new deep towed multichannel seismic streamer was developed within the gas hydrate initiative of the "Geotechnologien" program. The essential factor in terms of lateral resolution is determined by the size of the Fresnel zone. Using migration algorithms resolution could be enhanced up to half a wavelength, but this is only valid for the inline direction and will not recognize side effects. As the Fresnel zone is specified by the depth of source and receiver, as well as the velocity and frequency of the acoustic waves a lowering of source and receiver towards the sea floor will increase the lateral resolution. In our case we concentrated on the lowering of the receiver array resulting in hybrid system architecture, still using conventional surface operated airguns. Assuming a working depth of 3000 m and a source signal of 200 Hz the radius will be reduced from 106 m for surface configuration to 26 m for the hybrid case. The digital streamer comprises of single hydrophone nodes, which are coupled by cable sections of individual length. Due to this modular architecture the streamer lay out could be adapted to the source and target requirements. Currently 26 hydrophones are available which are sampled at 0.25 ms using a 24-bit A/D converter. Together with high-resolution data acquisition the request for good positioning is another issue. Therefore three of the hydrophone modules are extended to engineering modules. These nodes include a depth sensor as well as a compass, enabling the online display of a relative positioning of the streamer. Absolute coordinates of the deep towed system are measured through an ultra short baseline (USBL) system. Using a depth sensor within the deployed transponder the position could measured within 1% of the slant range even at very large offsets to the surface vessel. A permanent online connection to the deployed system is provided by a telemetry system, which is capable

  10. Experimental verification of the performance of the self-tunable loop-current array shielding module

    NASA Astrophysics Data System (ADS)

    Goleman, K.; Yamato, T.; Sasada, I.

    2006-04-01

    An active shielding module consisting of a self-tunable loop-current array is verified experimentally. Loop currents in the array are independently controlled by the magnetometer dedicated to each of them. Since magnetic field decays as 1/z3 along the distance z from the loop, the magnetic noise should be overcompensated at the location of the loop-current array to provide a good cancellation in the shielded area. In order to enable overcompensation in a stable feedback system, a small additional loop is combined to the magnetometer that reduces the magnetic direct coupling from the main loop current to the magnetometer. A feedback electronic circuit with a proportional-integral (PI) controller is combined with each of the array element to establish a stable canceling operation. An orthogonal fluxgate magnetometer is used to monitor incident magnetic noise. Shielding performance of an array consisting of nine loop currents arranged in a 3×3 grid was evaluated numerically and confirmed by experiments. Evaluation and measurements are done over the 1.5×1.5 m2 area 2 m in front of the array. The magnetic dipole disturbance source is placed 2 m further beyond the array. Attenuation of the magnetic field is calculated as 1/15. Experimental data show 1/10 attenuation.

  11. Design and Analysis of Tow-Steered Composite Shells Using Fiber Placement

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey

    2008-01-01

    In this study, a sub-scale advanced composite shell design is evaluated to determine its potential for use on a future aircraft fuselage. Two composite shells with the same nominal 8-ply [+/-45/+/-Theta](sub s) layup are evaluated, where Theta indicates a tow-steered ply. To build this shell, a fiber placement machine would be used to steer unidirectional prepreg tows as they are placed around the circumference of a 17-inch diameter right circular cylinder. The fiber orientation angle varies continuously from 10 degrees (with respect to the shell axis of revolution) at the crown, to 45 degrees on the side, and back to 10 degrees on the keel. All 24 tows are placed at each point on every fiber path in one structure designated as the shell with overlaps. The resulting pattern of tow overlaps causes the laminate thickness to vary between 8 and 16 plies. The second shell without tow overlaps uses the capability of the fiber placement machine to cut and add tows at any point along the fiber paths to fabricate a shell with a nearly uniform 8-ply laminate thickness. Issues encountered during the design and analysis of these shells are presented and discussed. Static stiffness and buckling loads of shells with tow-steered layups are compared with the performance of a baseline quasi-isotropic shell using both finite element analyses and classical strength of materials theory.

  12. Nuclear-resonance magnetometer with flowing liquid for superstrong inhomogeneous fields measuring

    NASA Astrophysics Data System (ADS)

    Davydov, V. V.; Dudkin, V. I.; Vologdin, V. A.

    2016-03-01

    Multichannel nuclear-resonance magnetometer for remote monitoring of induction and heterogeneity of a magnetic field in different areas inside and near a charged particle accelerator is considered. The maximal distance between the nuclear magnetic resonance signal detector and the magnetometer is 50 m. Measurement error is 0.5%, sensitivity of the magnetometer is 10-10 T/Hz1/2, measurement time of the magnetic field parameters in 24 control points is no more than 4 minutes.

  13. Eclipse project closeup of QF-106 under tow on takeoff on first flight December 20, 1997

    NASA Technical Reports Server (NTRS)

    1997-01-01

    OFF THE GROUND - The Kelly Space & Technology (KST)/USAF/NASA Eclipse project's modified QF-106 lifts off under tow on the project's first tethered flight on December 20, 1997. The successful 18-minute-long flight reached an altitude of 10,000 feet. NASA's Dryden Flight Research Center, Edwards, California, hosted the project, providing engineering and facility support as well as the project pilot. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

  14. Eclipse project closeup of QF-106 under tow on first tethered flight December 20, 1997

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Kelly Space and Technology (KST)/USAF/NASA Eclipse project's modified QF-106 is shown under tow on the project's first tethered flight on December 20, 1997. The successful 18-minute-long flight reached an altitude of 10,000 feet. NASA's Dryden Flight Research Center, Edwards, California, is hosting the project, providing engineering and facility support as well as the project pilot, Mark Stucky. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

  15. High-Tc SQUID Magnetometers for Industrial Applications

    NASA Astrophysics Data System (ADS)

    Diiorio, Mark; Yang, Kai-Yueh; Yoshizumi, Shozo; Haupt, Steven; Haran, Don; Koch, Roger; Lathrop, Dan; Trammel, Hoke

    1998-03-01

    We have developed high-Tc SQUID magnetometers for use in a variety of industrial applications. Relatively inexpensive direct-coupled magnetometers have been developed for low-frequency applications including fetal-magnetocardiography. A manufacturable process has been developed to reproducibly fabricate high-resistance (up to 6 Ω) SNS step-edge junctions with YBa_2Cu_3O_7-x as the superconductor and Ag-Au alloy as the normal metal. Magnetic field sensitivities at 77K of 22 ft/Hz^1/2 at 1 KHz and 32 ft/Hz^1/2 at 1 Hz have been achieved in a well-shielded laboratory environment. Current effort is focused on operation in an unshielded environment using flux dams(Milliken et al. Appl. Phys. Lett. 71 1857 (1997)) in conjunction with narrow superconducting pickup coils placed in parallel. An integrated magnetometer process has also been optimized for use in high-frequency applications. The integrated megnetometer utilizes two layers of YBa_2Cu_3O_7-x and one layer of deposited SrTiO_3, all on the same 24 mm x 5 mm substrate. The applications under development include the detection of the explosive material in non-metallic land mines using nuclear quadrupole resonance as well as the non-destructive evaluation of non-metallic composites using nuclear magnetic resonance. For operation in the MHz regime, these applications demand a high quality insulator layer and a robust SQUID that can withstand high current transients.

  16. Opportunity Science Using the Juno Magnetometer Investigation Star Trackers

    NASA Astrophysics Data System (ADS)

    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

  17. Kalman filtering for GPS/magnetometer integrated navigation system

    NASA Astrophysics Data System (ADS)

    Guo, Hang; Yu, Min; Zou, Chengwu; Huang, Wenwen

    2010-06-01

    This paper investigated the data processing method for a GPS/IMU/magnetometer integrated system with Kalman filtering (KF). As a result of GPS/IMU/magnetometer land vehicle system, dead-reckoning of magnetometer and accelerometer integrated subsystem bridged very well the GPS signal outage due to the trees on the two sides of the road. Both differential GPS data processing method and the carrier-phase method with magnetometers' outputs for predicting the car position, velocity, and acceleration (PVA) are presented. The results from DGPS with Kinematical Positioning (KINPOS) software shown that the averages of the north, east, and down direction standard deviation (short for "std") are 0.014, 0.010, and 0.018 m, respectively. The std of velocities and accelerations derived by the position and velocity differentiation are 10, 7, 13 mm/s, 7, 5, 9 mm/s 2, respectively. This method for getting velocities and accelerations requires higher accurate position coordinates. But the position accuracy has frequently been degraded in this case when the car drove under the trees or other similar kinematical environments. That caused the larger velocity and acceleration errors. While the results from the carrier-phase method are std of the velocities = 2.1 mm/s, 1.3 mm/s, 3.7 mm/s in north, east, down, and std of the accelerations = 1.5 mm/s 2, 0.9 mm/s 2, 2.3 mm/s 2 for the static test period; as compared with KINPOS software results, std of the velocity difference between the carrier-phase method and the DGPS method = 7 mm/s, 6.9 mm/s, 9.7 mm/s in north, east, down direction, and std of acceleration difference = 5.0 mm/s 2, 4.5 mm/s 2, 7.5 mm/s 2 in north, east, down direction for the kinematical test period. Obviously, errors come from both the carrier-phase method and DGPS velocity and acceleration results derived directly by the position differentiation. In addition, better accuracy of positions than that before KF has been got by means of velocities and accelerations derived

  18. Eddy current imaging with an atomic radio-frequency magnetometer

    NASA Astrophysics Data System (ADS)

    Wickenbrock, Arne; Leefer, Nathan; Blanchard, John W.; Budker, Dmitry

    2016-05-01

    We use a radio-frequency 85Rb alkali-vapor cell magnetometer based on a paraffin-coated cell with long spin-coherence time and a small, low-inductance driving coil to create highly resolved conductivity maps of different objects. We resolve sub-mm features in conductive objects, we characterize the frequency response of our technique, and by operating at frequencies up to 250 kHz we are able to discriminate between differently conductive materials based on the induced response. The method is suited to cover a wide range of driving frequencies and can potentially be used for detecting non-metallic objects with low DC conductivity.

  19. Magnetometer-Only Attitude and Rate Estimates for Spinning Spacecraft

    NASA Technical Reports Server (NTRS)

    Challa, M.; Natanson, G.; Ottenstein, N.

    2000-01-01

    A deterministic algorithm and a Kalman filter for gyroless spacecraft are used independently to estimate the three-axis attitude and rates of rapidly spinning spacecraft using only magnetometer data. In-flight data from the Wide-Field Infrared Explorer (WIRE) during its tumble, and the Fast Auroral Snapshot Explorer (FAST) during its nominal mission mode are used to show that the algorithms can successfully estimate the above in spite of the high rates. Results using simulated data are used to illustrate the importance of accurate and frequent data.

  20. Magnetometer probe with low temperature rotation and optical fibers

    NASA Astrophysics Data System (ADS)

    Pajerowski, D. M.; Meisel, M. W.

    2009-02-01

    A new probe has been developed that allows for both optical irradiation and uniaxial rotation, all in the low temperature environment of a commercial superconducting quantum interference device (SQUID) magnetometer. As part of the design process, various materials were investigated and characterized for their low temperature structural and magnetic properties, including nylon, Vespel, Delrin, Spiderwire monofilament, and PowerPro braided microfilament. Using this information, a prototype was built and operated. Characteristics of the probe will be presented along with a summary of the low temperature (T >= 2 K) and high magnetic field (H <= 7 T) properties of the construction materials.

  1. Places TV-track, ionosonde, and magnetometer operations

    NASA Astrophysics Data System (ADS)

    Chang, N. J. F.

    1981-06-01

    This report describes the TV tracking system, the slow-scan TV system, the KEL ionosonde, and the magnetometer that were operated in support of the PLACES experiment conducted at Eglin AFB, Florida in December 1980. A procedure for determining the proper launch time and aim point for both the beacon rockets and the probe rocket was developed after post-mission analysis of the first two releases. This procedure contributed to a successful beacon occultation for Event IRIS, and a successful probe penetration for Event JAN.

  2. Study of Subsonic Flow Over a TOW 2B Missile

    NASA Astrophysics Data System (ADS)

    Goudarzi, Koorosh; Jamali, Mehdi

    2016-01-01

    The objective of this investigation is to study the subsonic flow over a missile. In this paper, a model of TOW 2B missile is studied. Two computational approaches are being explored, namely solutions based on the Reynolds-averaged compressible Navier-Stokes equations and solutions based on the inviscid flow (small disturbance theory). The simulations are performed at the Mach number of 0.6, 0.7, 0.8, 0.9 and 1.0 at four angles of attack of 2, 4, 6 and 8 degree. Results obtained from analytical simulation are compared with numerical data. It is found that lift and drag coefficients would go up by increasing of the angle of attack and the Mach number. Trend of changes of the results that obtained from the small disturbance theory is roughly as same as the numeric solution.

  3. Horizontal ichthyoplankton tow-net system with unobstructed net opening

    USGS Publications Warehouse

    Nester, Robert T.

    1987-01-01

    The larval fish sampler described here consists of a modified bridle, frame, and net system with an obstruction-free net opening and is small enough for use on boats 10 m or less in length. The tow net features a square net frame attached to a 0.5-m-diameter cylinder-on-cone plankton net with a bridle designed to eliminate all obstructions forward of the net opening, significantly reducing currents and vibrations in the water directly preceding the net. This system was effective in collecting larvae representing more than 25 species of fish at sampling depths ranging from surface to 10 m and could easily be used at greater depths.

  4. Automated Tow Placed LaRC(TM)-PETI-5 Composites

    NASA Technical Reports Server (NTRS)

    Hou, T. H.; Belvin, H. L.; Johnston, N. J.

    2001-01-01

    LaRC(TM)-PETI-5 is a PhenylEthynyl-Terminated Imide resin developed at NASA Langley Research Center (LaRC) during the 1990s. It offers a combination of attractive composite and adhesive properties. IM7/LaRC(TM)-PETI-5 composites exhibit thermal and thermo-oxidative stability typical of polyimides, superior chemical resistance and processability, excellent mechanical properties, toughness and damage tolerance. It was selected for study in the High Speed Research program aimed at developing technologies for a future supersonic aircraft, the High Speed Civil Transport, with a projected life span of 60 000 h at a cruise speed up to Mach 2.4. Robust autoclave processing cycles for LaRC(TM)-PETI-5 composites have been thoroughly designed and demonstrated, which involved hand lay-up of solvent-ladened 'wet' prepregs. However, this type of processing is not only costly but also environmentally unfriendly. Volatile management and shrinkage could become serious problems in the fabrication of large complex airframe structural subcomponents. Robotic tow placement technology utilizing 'dry' material forms represents a new fabrication process which overcomes these deficiencies. This work evaluates and compares mechanical properties of composites fabricated by heated head automated tow placement (dry process) with those obtained by hand lay-up/autoclave fabrication (wet process). Thermal and rheological properties of the robotically as-placed uncured composites were measured. A post-cure cycle was designed due to the requirement of the PETI-5 resin for a 370 C/1 h hold to reach full cure, conditions which cannot be duplicated during heated head robotic placement. Mechanical properties such as 0 degree flexural strength and modulus, open hole tensile and compressive strength and moduli, reduced section compression dogbone compressive strength, and modified zippora-medium small (MZ-MS) tensile and compressive properties were obtained on the post-cured panels. These properties

  5. A Physics-based Automated Technique for the Detection of Field Line Resonance Frequency in Ground Magnetometer Data

    NASA Astrophysics Data System (ADS)

    Boudouridis, A.; Zesta, E.; Moldwin, M.

    2015-12-01

    The accurate determination of the Field Line Resonance (FLR) frequency of a resonating geomagnetic field line is necessary for the remote monitoring of the plasmaspheric mass density during geomagnetic storms and quiet times alike. Under certain assumptions the plasmaspheric mass density at the equator is inversely proportional to the square of the FLR frequency. The most common techniques to determine the FLR frequency from ground magnetometer measurements are the amplitude ratio and phase difference techniques, both based on geomagnetic field measurements at two latitudinally separated ground stations. Previously developed automated techniques have used statistical methods to pinpoint the FLR frequency using the amplitude ratio and phase difference calculations. We now introduce a physics-based automated technique that can reproduce the resonant wave characteristics from the two ground station data, and from those determine the FLR frequency. The advantage of the new technique, besides moving away from ambiguous statistical manipulations of the ground data, is the estimation of physically determined errors of the FLR frequency, which can yield physically determined errors of the equatorial plasmaspheric mass density. We present preliminary results of the new technique calculations, and test it using data from the new Inner-Magnetospheric Array for Geospace Science (iMAGS) ground magnetometer chain along the coast of Chile and the east coast of the United States. We compare the results with the results of previously published statistical automated techniques.

  6. High-resolution fully vectorial scanning Kerr magnetometer.

    PubMed

    Flajšman, Lukáš; Urbánek, Michal; Křižáková, Viola; Vaňatka, Marek; Turčan, Igor; Šikola, Tomáš

    2016-05-01

    We report on the development of a high-resolution scanning magnetometer, which fully exploits the vectorial nature of the magneto-optical Kerr effect. The three-dimensional nature of magnetization is at the basis of many micromagnetic phenomena and from these data, we can fully characterize magnetization processes of nanostructures in static and dynamic regimes. Our scanning Kerr magnetometer uses a high numerical aperture microscope objective where the incident light beam can be deterministically deviated from the objective symmetry axis, therefore, both in-plane (via the longitudinal Kerr effect) and out-of-plane (via the polar Kerr effect) components of the magnetization vector may be detected. These components are then separated by exploiting the symmetries of the polar and longitudinal Kerr effects. From four consecutive measurements, we are able to directly obtain the three orthogonal components of the magnetization vector with a resolution of 600 nm. Performance of the apparatus is demonstrated by a measurement of 3D magnetization vector maps showing out-of-plane domains and in-plane domain walls in an yttrium-iron-garnet film and on a study of magnetization reversal in a 4-μm-wide magnetic disk. PMID:27250432

  7. Lunar electrical conductivity, permeability and temperature from Apollo magnetometer experiments

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    Magnetometers were deployed at four Apollo sites on the moon to measure remanent and induced lunar magnetic fields. Measurements from this network of instruments were used to calculate the electrical conductivity, temperature, magnetic permeability, and iron abundance of the lunar interior. The measured lunar remanent fields range from 3 gammas minimum at the Apollo 15 site to 327 gammas maximum at the Apollo 16 site. Simultaneous magnetic field and solar plasma pressure measurements show that the remanent fields at the Apollo 12 and 16 sites interact with, and are compressed by, the solar wind. Remanent fields at Apollo 12 and Apollo 16 are increased 16 gammas and 32 gammas, respectively, by a solar plasma bulk pressure increase of 1.5 X 10 to the -7th power dynes/sq cm. Global lunar fields due to eddy currents, induced in the lunar interior by magnetic transients, were analyzed to calculate an electrical conductivity profile for the moon. From nightside magnetometer data in the solar wind it was found that deeper than 170 km into the moon the conductivity rises from .0003 mhos/m to .10 mhos/m at 100 km depth. Recent analysis of data obtained in the geomagnetic tail, in regions free of complicating plasma effects, yields results consistent with nightside values.

  8. Miniaturized superconducting quantum interference magnetometers for high sensitivity applications

    NASA Astrophysics Data System (ADS)

    Granata, C.; Vettoliere, A.; Russo, M.

    2007-09-01

    A miniaturized niobium based dc superconducting quantum interference device (SQUID) magnetometer for high magnetic field sensitivity applications has been developed. The sensing coil consists of an integrated square superconducting coil with a length of 3mm, involving a device area much smaller with respect to the standard SQUID magnetometers with a comparable magnetic field sensitivity; so it allows increasing the spatial resolution keeping the magnetic field sensitivity unaltered. Furthermore, a small pickup coil minimizes its antenna gain, reducing the radio frequency interference. At T =4.2K, the sensors have shown smooth and resonance free V-Φ characteristics and an intrinsic white magnetic field noise spectral density as low as 5.8fT /Hz1/2, measured in flux locked loop configuration. The good agreement with the theoretical predictions guarantees the reliability and the controllability of the sensors. Due to their compactness and good characteristic parameters, such sensors are suitable for large multichannel systems used in biomagnetic imaging.

  9. High-Tc SQUID magnetometer system with active cancellation

    NASA Astrophysics Data System (ADS)

    Kuriki, S.; Oyama, H.; Hayashi, A.; Washio, T.; Fujita, M.; Hirata, Y.

    2002-05-01

    Recent developments of high-Tc SQUIDs have enabled high sensitivity magnetometers to be used in wide range of places, such as laboratory and outdoor fields. At the early stage of developing multichannel system for measurement of magnetocardiogram (MCG) in clinical application, we have fabricated a single channel high-Tc SQUID magnetometer system. The system includes a direct-coupled SQUID with slot structure, a simple magnetically shielded room (MSR), and some active compensation electronics for the purpose of reducing various environmental field noises. A novel active noise cancellation was made by using a combination of a normal conducting detection coil that was horizontally wound in the middle height of the MSR, and two compensation coils that were wound at the top and bottom of the MSR. In addition, adaptive noise cancellation was supplemented by means of adaptive digital filter that was implemented in a digital signal processor. A total noise field attenuation of 50-60 dB was attained at 0.5-100 Hz. Low noise signals from the human heart were measured with a high-Tc SQUID in the noise reduced space in the MSR.

  10. High-resolution fully vectorial scanning Kerr magnetometer

    NASA Astrophysics Data System (ADS)

    Flajšman, Lukáš; Urbánek, Michal; Křižáková, Viola; VaÅatka, Marek; Turčan, Igor; Šikola, Tomáš

    2016-05-01

    We report on the development of a high-resolution scanning magnetometer, which fully exploits the vectorial nature of the magneto-optical Kerr effect. The three-dimensional nature of magnetization is at the basis of many micromagnetic phenomena and from these data, we can fully characterize magnetization processes of nanostructures in static and dynamic regimes. Our scanning Kerr magnetometer uses a high numerical aperture microscope objective where the incident light beam can be deterministically deviated from the objective symmetry axis, therefore, both in-plane (via the longitudinal Kerr effect) and out-of-plane (via the polar Kerr effect) components of the magnetization vector may be detected. These components are then separated by exploiting the symmetries of the polar and longitudinal Kerr effects. From four consecutive measurements, we are able to directly obtain the three orthogonal components of the magnetization vector with a resolution of 600 nm. Performance of the apparatus is demonstrated by a measurement of 3D magnetization vector maps showing out-of-plane domains and in-plane domain walls in an yttrium-iron-garnet film and on a study of magnetization reversal in a 4-μm-wide magnetic disk.

  11. Mechanical characterization of two thermoplastic composites fabricated by automated tow placement

    NASA Technical Reports Server (NTRS)

    Dickinson, Larry C.; Deaton, Jerry W.

    1993-01-01

    AS4/PEEK towpreg and IM7/Radel 8320 slit tape were used to make flat panels by automated tow placement. The panels were tested in notched and un-notched tension, notched and un-notched compression and compression after impact (CAI) at room temperature and under hot/wet conditions (notched and un-notched compression and CAI only). The properties were compared with AS4/PEEK tape laminate properties found in the literature. The tow placed AS4/PEEK material was stronger in tension but weaker in compression than the AS4/PEEK tape laminates. The tow placed AS4/PEEK was stronger but less stiff than the tow placed IM7/Radel 8320 in all compression tests. The IM7/Radel performed better in all other mechanical tests. The IM7/Radel outperformed the AS4/PEEK in all CAI tests.

  12. 46 CFR 11.465 - Requirements for endorsements as mate (pilot) of towing vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 CFR 11.429 and 11.456, then you may obtain an endorsement as mate (pilot) of towing vessels by... appropriate TOAR; (3) Successfully completing the appropriate apprentice mate exam; and (4) Having a...

  13. On-site experiment for towing procedure of pre-fabricated tendon of TLP

    SciTech Connect

    Morikawa, Masao; Ishikawa, Kuniteru; Suzuki, Hideyuki; Yoshida, Koichiro

    1994-12-31

    Research and development of the Tension Leg Platform (TLP) have been performed in the Offshore Oil and Gas Production Platform Project of Japan Ocean Industries Association (JOIA) promoted by the Ministry of International Trade and Industry, Japan (MITI). In this project, the tendons that are planned to be fabricated and assembled on the land in an overall length will be horizontally toward to the site. After that, they will be installed there. The towing procedure, however, has been established neither theoretically nor empirically. Therefore, the on-site experiment was performed to investigate whether it is possible to plan the towing procedure at the sea. The bending moment and the towing force of the tendon model during the towing procedure were measured.

  14. Driven microswimmers on a 2D substrate: A stochastic towed sled model

    NASA Astrophysics Data System (ADS)

    Marchegiani, Giampiero; Marchesoni, Fabio

    2015-11-01

    We investigate, both numerically and analytically, the diffusion properties of a stochastic sled sliding on a substrate, subject to a constant towing force. The problem is motivated by the growing interest in controlling transport of artificial microswimmers in 2D geometries at low Reynolds numbers. We simulated both symmetric and asymmetric towed sleds. Remarkable properties of their mobilities and diffusion constants include sidewise drifts and excess diffusion peaks. We interpret our numerical findings by making use of stochastic approximation techniques.

  15. Driven microswimmers on a 2D substrate: A stochastic towed sled model

    SciTech Connect

    Marchegiani, Giampiero; Marchesoni, Fabio

    2015-11-14

    We investigate, both numerically and analytically, the diffusion properties of a stochastic sled sliding on a substrate, subject to a constant towing force. The problem is motivated by the growing interest in controlling transport of artificial microswimmers in 2D geometries at low Reynolds numbers. We simulated both symmetric and asymmetric towed sleds. Remarkable properties of their mobilities and diffusion constants include sidewise drifts and excess diffusion peaks. We interpret our numerical findings by making use of stochastic approximation techniques.

  16. Recovery of a temperate reef assemblage in a marine protected area following the exclusion of towed demersal fishing.

    PubMed

    Sheehan, Emma V; Stevens, Timothy F; Gall, Sarah C; Cousens, Sophie L; Attrill, Martin J

    2013-01-01

    Marine Protected Areas MPA have been widely used over the last 2 decades to address human impacts on marine habitats within an ecosystem management context. Few studies have quantified recovery of temperate rocky reef communities following the cessation of scallop dredging or demersal trawling. This is critical information for the future management of these habitats to contribute towards conservation and fisheries targets. The Lyme Bay MPA, in south west UK, has excluded towed demersal fishing gear from 206 km(2) of sensitive reef habitat using a Statutory Instrument since July 2008. To assess benthic recovery in this MPA we used a flying video array to survey macro epi-benthos annually from 2008 to 2011. 4 treatments (the New Closure, previously voluntarily Closed Controls and Near or Far Open to fishing Controls) were sampled to test a recovery hypothesis that was defined as 'the New Closure becoming more similar to the Closed Controls and less similar to the Open Controls'. Following the cessation of towed demersal fishing, within three years positive responses were observed for species richness, total abundance, assemblage composition and seven of 13 indicator taxa. Definitive evidence of recovery was noted for species richness and three of the indicator taxa (Pentapora fascialis, Phallusia mammillata and Pecten maximus). While it is hoped that MPAs, which exclude anthropogenic disturbance, will allow functional restoration of goods and services provided by benthic communities, it is an unknown for temperate reef systems. Establishing the likely timescales for restoration is key to future marine management. We demonstrate the early stages of successful recruitment and link these to the potential wider ecosystem benefits including those to commercial fisheries. PMID:24391841

  17. A 3 He-129 Xe co-magnetometer with 87 Rb magnetometry

    NASA Astrophysics Data System (ADS)

    Limes, Mark; Sheng, Dong; Romalis, Mike

    2016-05-01

    We report progress on a 3 He-129 Xe co-magnetometer detected with a 87 Rb magnetometer. The noble-gas co-magnetometer is insensitive to any long-term bias field drifts, but the presence of hot Rb can cause instability in the ratio of 3 He-129 Xe precession frequencies. We use a sequence of Rb π pulses to suppress the instability due to Rb-noble gas interactions by a factor of 104 along all three spatial axes. For detection, our 87 Rb magnetometer operates using single-axis 87 Rb π pulses with σ+ /σ- pumping-this technique decouples the 87 Rb magnetometer from bias fields, and allows for SERF operation. We are presently investigating systematic effects due to combinations of several imperfections, such as longitudinal noble gas polarization, imperfect 87 Rb π pulses, and 87 Rb pump light shifts. Thus far, our 87 Rb magnetometer has a sensitivity of 40 fT/√{Hz}, and our 3 He-129 Xe co-magnetometer has achieved a single-shot precession frequency ratio error of 20 nHz and a long-term bias drift of 8 nHz at 7 h. We are developing the co-magnetometer for use as an NMR gyro, and to search for possible spin-gravity interactions. Supported by DARPA and NSF.

  18. Electromagnetic imaging with atomic magnetometers: a novel approach to security and surveillance

    NASA Astrophysics Data System (ADS)

    Hussain, Sarah; Marmugi, Luca; Deans, Cameron; Renzoni, Ferruccio

    2016-05-01

    We describe our research programme on the use of atomic magnetometers to detect conductive objects via electromagnetic induction. The extreme sensitivity of atomic magnetometers at low frequencies, up to seven orders of magnitude higher than a coil-based system, permits deep penetration through different media and barriers, and in various operative environments. This eliminates the limitations usually associated with electromagnetic detection.

  19. Design and Manufacturing of Tow-Steered Composite Shells Using Fiber Placement

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey; Tatting, Brian F.; Smith, Brett H.; Stevens, Randy S.; Occhipiniti, Gina P.; Swift, Jonathan B.; Achary, David C.; Thornburgh, Robert P.

    2009-01-01

    Advanced composite shells that may offer the potential to improve the structural performance of future aircraft fuselage structures were developed under this joint NASA-industry collaborative effort. Two cylindrical shells with tailored, tow-steered layups and continuously varying fiber angle orientations were designed and built at the National Center for Advanced Manufacturing - Louisiana Partnership. The shells were fabricated from unidirectional IM7/8552 graphite-epoxy pre-preg slit tape material fiber-placed on a constant-diameter mandrel. Each shell had the same nominal 8-ply [plus or minus 45/plus or minus Theta]s layup, where the nominal fiber angle in the tow-steered plies varied continuously from 10 degrees along the crown to 45 degrees on each side, then back to 10 degrees on the keel. One shell was fabricated with all 24 tows placed during each pass of the fiber placement machine, resulting in many tow overlaps on the shell surface. The fiber placement machine's individual tow cut/restart capability was also used to manufacture a second shell with tow drops and a more uniform laminate thickness. This paper presents an overview of the detailed design and manufacturing processes for these shells, and discusses issues encountered during their fabrication and post-cure evaluation. Future plans for structural testing and analyses of the shells are also discussed.

  20. M2-F1 under tow across lakebed by car

    NASA Technical Reports Server (NTRS)

    1963-01-01

    This 20-second clip shows the M2-F1 being towed by the Pontiac across Rogers Dry Lakebed. The M2-F1 lifting body, dubbed the 'flying bathtub' by the media, was the precursor of a remarkable series of wingless flying vehicles that contributed data used in the Space Shuttles, the X-33 Advanced Technology Demonstrator for the next century's Reusable Launch Vehicle, and the X-38 Technology Demonstrator for crew return from the International Space Station. Based on the ideas and basic design of Alfred J. Eggers and others at the Ames Aeronautical Laboratory (now the Ames Research Center), Mountain View, California, in the mid-1950's, the M2-F1 was built in 1962-63 over a four-month period for a cost of only about $30,000, plus an additional $8,000-$10,000 for an ejection seat. Engineers and technicians at the NASA Flight Research Center (now NASA Dryden) kept costs low by designing and fabricating it partly in-house, with the plywood shell constructed by a local sailplane builder. Someone at the time estimated that it would have cost a major aircraft company $150,000 to build the same vehicle. Unlike the later lifting bodies, the M2-F1 was unpowered and was initially towed by a souped-up Pontiac convertible until it was airborne. Later a C-47 took over the towing duties. Flown by such famous research pilots as Milt Thompson, Bruce Peterson, Chuck Yeager, and Bill Dana, the lightweight flying bathtub demonstrated that a wingless vehicle shaped for reentry into the Earth's atmosphere from space could be flown and landed safely. Flown from 1963 to 1966, the lightweight M2-F1 paved the way for the heavyweight M2-F2, M2`F3, HL-10, X-24A, and X-24B lifting bodies that flew under rocket power after launch from a B-52 mothership. The heavyweights flew from 1966 to 1975, demonstrating the viability and versatility of the wingless configuration and the ability of a vehicle with low lift-over-drag characteristics to fly to high altitudes and then to land precisely with their

  1. The Swarm Absolute Scalar Magnetometers now operating in orbit

    NASA Astrophysics Data System (ADS)

    Fratter, Isabelle; Leger, Jean-Michel; Bertrand, François; Jager, Thomas; Hulot, Gauthier

    2014-05-01

    Swarm is one of the Earth Explorer Missions run by the European Space Agency. Its principal goal is to make the best ever survey of the Earth's magnetic field and ionosphere and to study how they vary over space and time. This will be achieved by a constellation of three identical satellites, launched on the 22nd of November 2013. In order to observe the magnetic field thoroughly, each satellite carries two magnetometers: a Vector Field Magnetometer coupled with a star tracker camera, to measure the direction of the magnetic field in space, and an Absolute Scalar Magnetometer (ASM), to measure its intensity. The ASM is the French contribution to the Swarm mission. This new generation instrument, based on the atomic spectroscopy of the helium 4 metastable state, was developed by CEA-Leti (1) in Grenoble with technical assistance and financing from CNES (2) and scientific support from IPGP (3). As the Swarm magnetic reference, the ASM scalar performances are crucial for the mission's success. Thanks to a new dedicated design, the ASM offers the best precision and absolute accuracy ever attained in space, with similar performances all along the orbit. The ASM will thus deliver high resolution scalar measurements at 1 Hz for the in-flight calibration of the vector field data over the 4 year mission. It can also be operated at a much higher sampling rate ("burst" mode at 250 Hz). In addition, on an experimental basis, this instrument also takes vector field measurements, which are being validated jointly by CEA-Leti and IPGP, with support from CNES. This poster presents the capabilities and working principle of this instrument as well as the results of the in-flight verifications carried out during the 3 first months in orbit, including the performances, the last status and future prospects. 1 CEA-Leti : French Atomic Energy and Alternative Energies Commission - Electronics and Information Technology Laboratory 2 CNES : Centre National d'Etudes Spatiales - French Space

  2. Swarm Absolute Scalar Magnetometers first in-orbit results

    NASA Astrophysics Data System (ADS)

    Fratter, Isabelle; Léger, Jean-Michel; Bertrand, François; Jager, Thomas; Hulot, Gauthier; Brocco, Laura; Vigneron, Pierre

    2016-04-01

    The ESA Swarm mission will provide the best ever survey of the Earth's magnetic field and its temporal evolution. This will be achieved by a constellation of three identical satellites, launched together on the 22nd of November 2013. In order to observe the magnetic field thoroughly, each satellite carries two magnetometers: a Vector Field Magnetometer (VFM) coupled with a star tracker camera, to measure the direction of the magnetic field in space, and an Absolute Scalar Magnetometer (ASM), to measure its intensity. The ASM is the French contribution to the Swarm mission. This new generation instrument was designed by CEA-Leti and developed in close partnership with CNES, with scientific support from IPGP. Its operating principle is based on the atomic spectroscopy of the helium 4 metastable state. It makes use of the Zeeman's effect to transduce the magnetic field into a frequency, the signal being amplified by optical pumping. The primary role of the ASM is to provide absolute measurements of the magnetic field's strength at 1 Hz, for the in-flight calibration of the VFM. As the Swarm magnetic reference, the ASM scalar performance is crucial for the mission's success. Thanks to its innovative design, the ASM offers the best precision, resolution and absolute accuracy ever attained in space, with similar performance all along the orbit. In addition, thanks to an original architecture, the ASM implements on an experimental basis a capacity for providing simultaneously vector measurements at 1 Hz. This new feature makes it the first instrument capable of delivering both scalar and vector measurements simultaneously at the same point. Swarm offers a unique opportunity to validate the ASM vector data in orbit by comparison with the VFM's. Furthermore, the ASM can provide scalar data at a much higher sampling rate, when run in "burst" mode at 250 Hz, with a 100 Hz measurement bandwidth. An analysis of the spectral content of the magnetic field above 1 Hz becomes thus

  3. Magnetic arrays

    DOEpatents

    Trumper, D.L.; Kim, W.; Williams, M.E.

    1997-05-20

    Electromagnet arrays are disclosed which can provide selected field patterns in either two or three dimensions, and in particular, which can provide single-sided field patterns in two or three dimensions. These features are achieved by providing arrays which have current densities that vary in the windings both parallel to the array and in the direction of array thickness. 12 figs.

  4. Magnetic arrays

    SciTech Connect

    Trumper, David L.; Kim, Won-jong; Williams, Mark E.

    1997-05-20

    Electromagnet arrays which can provide selected field patterns in either two or three dimensions, and in particular, which can provide single-sided field patterns in two or three dimensions. These features are achieved by providing arrays which have current densities that vary in the windings both parallel to the array and in the direction of array thickness.

  5. Highly stable atomic vector magnetometer based on free spin precession.

    PubMed

    Afach, S; Ban, G; Bison, G; Bodek, K; Chowdhuri, Z; Grujić, Z D; Hayen, L; Hélaine, V; Kasprzak, M; Kirch, K; Knowles, P; Koch, H-C; Komposch, S; Kozela, A; Krempel, J; Lauss, B; Lefort, T; Lemière, Y; Mtchedlishvili, A; Naviliat-Cuncic, O; Piegsa, F M; Prashanth, P N; Quéméner, G; Rawlik, M; Ries, D; Roccia, S; Rozpedzik, D; Schmidt-Wellenburg, P; Severjins, N; Weis, A; Wursten, E; Wyszynski, G; Zejma, J; Zsigmond, G

    2015-08-24

    We present a magnetometer based on optically pumped Cs atoms that measures the magnitude and direction of a 1 μT magnetic field. Multiple circularly polarized laser beams were used to probe the free spin precession of the Cs atoms. The design was optimized for long-time stability and achieves a scalar resolution better than 300 fT for integration times ranging from 80 ms to 1000 s. The best scalar resolution of less than 80 fT was reached with integration times of 1.6 to 6 s. We were able to measure the magnetic field direction with a resolution better than 10 μrad for integration times from 10 s up to 2000 s. PMID:26368184

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

    PubMed

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

    2015-01-01

    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. PMID:25746095

  7. A three-axis SQUID-based absolute vector magnetometer

    NASA Astrophysics Data System (ADS)

    Schönau, T.; Zakosarenko, V.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, M.; Meyer, H.-G.

    2015-10-01

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth's magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz1/2. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

  8. Single-beam three-axis atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Huang, Haichao; Dong, Haifeng; Chen, Lin; Gao, Yang

    2016-08-01

    A single-beam atomic magnetometer being operated near zero-field and measuring three-axis fields simultaneously is demonstrated. We produce a rotating field on the x-0-y plane with the frequency of 90 Hz and a modulation field in the z axis at 130 Hz. The rotating field enables a nonzero z axis output when the transverse fields are zeroed using feedback systems. Based on the phase difference of π / 2 , x and y axes fields can be measured using one lock-in amplifier. Magnetic field sensitivities of 300 fT/Hz1/2 in x and y axes and 3 pT/Hz1/2 in the z axis are achieved.

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

    PubMed Central

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

    2015-01-01

    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. PMID:25746095

  10. Dual technique magnetometer experiment for the Cassini Orbiter spacecraft

    NASA Technical Reports Server (NTRS)

    Southwood, D. J.; Balogh, A.; Smith, E. J.

    1992-01-01

    The dual technique magnetometer to fly on the Cassini Saturn Orbiter Spacecraft is described. The instrument combines two separate techniques of measuring the magnetic field in space using both fluxgate and vector helium devices. In addition, the instrument can be operated in a special scalar mode which is to be used near the planet for highly accurate determination of the interior field of the planet. As well as the planetary field, the instrument will make large contributions to the scientific measurements of the planetary magnetosphere, the highly electrically conducting region of space surrounding Saturn permeated by the Saturnian field, the interaction of Saturn and the interplanetary medium and the interaction of Titan with its space environment.

  11. Magsat vector magnetometer calibration using Magsat geomagnetic field measurements

    NASA Technical Reports Server (NTRS)

    Lancaster, E. R.; Jennings, T.; Morrissey, M.; Langel, R. A.

    1980-01-01

    From the time of its launch on Oct. 30, 1979 into a nearly polar, Sun synchronous orbit, until it reentered the Earth's atmosphere on June 11, 1980, Magsat measured and transmitted more than three complete sets of global magnetic field data. The data obtained from the mission will be used primarily to compute a currently accurate model of the Earth's main magnetic field, to update and refine world and regional magnetic charts, and to develop a global scalar and vector crustal magnetic anomaly map. The in-flight calibration procecure used for 39 vector magnetometer system parameters is described as well as results obtained from some data sets and the numerical studies designed to evaluate the results.

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

    PubMed

    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. PMID:19123577

  13. Ultrasensitive 3He magnetometer for measurements of high magnetic fields

    NASA Astrophysics Data System (ADS)

    Nikiel, Anna; Blümler, Peter; Heil, Werner; Hehn, Manfred; Karpuk, Sergej; Maul, Andreas; Otten, Ernst; Schreiber, Laura M.; Terekhov, Maxim

    2014-11-01

    We describe a 3He magnetometer capable to measure high magnetic fields ( B> 0.1 T) with a relative accuracy of better than 10-12. Our approach is based on the measurement of the free induction decay of gaseous, nuclear spin polarized 3He following a resonant radio frequency pulse excitation. The measurement sensitivity can be attributed to the long coherent spin precession time T2 ∗ being of order minutes which is achieved for spherical sample cells in the regime of "motional narrowing" where the disturbing influence of field inhomogeneities is strongly suppressed. The 3He gas is spin polarized in situ using a new, non-standard variant of the metastability exchange optical pumping. We show that miniaturization helps to increase T2 ∗ further and that the measurement sensitivity is not significantly affected by temporal field fluctuations of order 10-4.

  14. Midlatitude Pi2 pulsations: AFGL and ISEE magnetometer observations correlated

    SciTech Connect

    Hughes, W.J.; Singer, H.J.; Maynard, N.C.

    1982-01-01

    The ISEE observations of the pi2 magnetic pulsations occuring substorm onset in the inner magnetosphere are discussed. One of these events which was also detected as a pi2 event by the AFGL midlatitude magnetometers is considered. The event occurred when the foot of the ISEE field line was over North America. The ground and satellite signals are remarkably similar: they start and stop at the same time, have the same period and can be correlated cycle by cycle. The waves are detected in the electric field data from ISEE 1 and in the magnetic field data from both ISEE 1 and ISEE 2. Calculation of the Poynting vector at ISEE 1 shows that the energy flowed mainly westward, but that there was also a component towards the nearer (southern) ionospheric foot of the field line. The phases between the various field components measured by ISEE 1 and 2 indicate that this is a standing hydromagnetic oscillation.

  15. Compact Atomic Magnetometer for Global Navigation (NAV-CAM)

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Larsen, Michael

    2014-05-01

    Northrop Grumman Navigation Systems Division is developing an atom-based magnetometer technology that has the potential for providing a global position reference independent of GPS. The NAV-CAM sensor is a direct outgrowth of the Nuclear Magnetic Resonance Gyro under development by the same technical team. It will be the only known magnetic field sensor capable of providing all 3 axes of magnetic vector direction and magnitude simultaneously with a whole-field scalar measurement, all within a single multi-axis sensing element measuring 4mm cube or smaller, essentially eliminating many of the problems encountered when using physically separate sensors or sensing elements. According to information presented by Ariyur et al. at the 2010 American Control Conference [1], the anticipated accuracy of 10 pico-Tesla (pT) and precision of <0.5 pT of the NAV-CAM sensor will enable magnetic determination of position with 20 meter accuracy and 1 meter resolution.

  16. The Search-coil Magnetometer for the THOR mission

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    Turbulence Heating ObserveR (THOR) is the first mission ever flown in space 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.

  17. Fiber-optic three axis magnetometer prototype development

    NASA Technical Reports Server (NTRS)

    Wang, Thomas D.; Mccomb, David G.; Kingston, Bradley R.; Dube, C. Michael; Poehls, Kenneth A.; Wanser, Keith

    1989-01-01

    The goal of this research program was to develop a high sensitivity, fiber optic, interferometric, three-axis magnetometer for interplanetary spacecraft applications. Dynamics Technology, Inc. (DTI) has successfully integrated a low noise, high bandwidth interferometer with high sensitivity metallic glass transducers. Also, DTI has developed sophisticated signal processing electronics and complete data acquisition, filtering, and display software. The sensor was packaged in a compact, low power and weight unit which facilitates deployment. The magnetic field sensor had subgamma sensitivity and a dynamic range of 10(exp 5) gamma in a 10 Hz bandwidth. Furthermore, the vector instrument exhibited the lowest noise level when only one axis was in operation. A system noise level of 1 gamma rms was observed in a 1 Hz bandwidth. However, with the other two channels operating, the noise level increased by about one order of magnitude. Higher system noise was attributed to cross-channel interference among the dither fields.

  18. A three-axis SQUID-based absolute vector magnetometer

    SciTech Connect

    Schönau, T.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, H.-G.; Zakosarenko, V.; Meyer, M.

    2015-10-15

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth’s magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz{sup 1/2}. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

  19. Construction and Operation of a Differential Hall Element Magnetometer

    NASA Astrophysics Data System (ADS)

    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.

  20. Magnetoencephalography with a chip-scale atomic magnetometer

    PubMed Central

    Sander, T. H.; Preusser, J.; Mhaskar, R.; Kitching, J.; Trahms, L.; Knappe, S.

    2012-01-01

    We report on the measurement of somatosensory-evoked and spontaneous magnetoencephalography (MEG) signals with a chip-scale atomic magnetometer (CSAM) based on optical spectroscopy of alkali atoms. The uncooled, fiber-coupled CSAM has a sensitive volume of 0.77 mm3 inside a sensor head of volume 1 cm3 and enabled convenient handling, similar to an electroencephalography (EEG) electrode. When positioned over O1 of a healthy human subject, α-oscillations were observed in the component of the magnetic field perpendicular to the scalp surface. Furthermore, by stimulation at the right wrist of the subject, somatosensory-evoked fields were measured with the sensors placed over C3. Higher noise levels of the CSAM were partly compensated by higher signal amplitudes due to the shorter distance between CSAM and scalp. PMID:22567591

  1. Reply to a paper on the use of two magnetometers for magnetic field measurements on a spacecraft

    NASA Technical Reports Server (NTRS)

    Ness, N. F.; Behannon, K. W.; Lepping, R. P.; Neubauer, F. M.; Schatten, K. H.

    1972-01-01

    The use of two magnetometers for measuring the ambient magnetic field of spacecraft is compared with the single magnetometer variance method. It is shown that the dual magnetometer concept was developed for missions which are conducted with attitude stabilized spacecraft which have been constructed without an adequate magnetics control program. Specific methods for applying the dual magnetometer technique are described and an error analysis is conducted to determine the accuracy of the results.

  2. Paresev 1-B in flight with tow cable

    NASA Technical Reports Server (NTRS)

    1964-01-01

    The Paresev 1-B tested the concept of a paraglider, designed to enable a Gemini capsule to fly to a controlled ground landing. This would remove the need to make an ocean splashdown at the end of a spaceflight. Once the paraglider was deployed, the Gemini crew could use it to steer toward a touchdown point and to land on three retractable skids. Because the paraglider represented an unproved technology, approval was given to build a simple test vehicle to try out the concept. The paraglider research vehicle, or Paresev, was built of steel tubing, with a fabric paraglider. The Paresev was unpowered, so it had to be towed aloft either by ground vehicles or aircraft, such as a biplane or a light aircraft. The Paresev was a demanding aircraft to fly. Milt Thompson said that he found it more difficult to handle than the later lifting bodies. Due to technical and cost problems, the Gemini spacecraft never used the paraglider, and all missions made ocean splashdowns.

  3. Response of automated tow placed laminates to stress concentrations

    NASA Technical Reports Server (NTRS)

    Cairns, Douglas S.; Ilcewicz, Larry B.; Walker, Tom

    1993-01-01

    In this study, the response of laminates with stress concentrations is explored. Automated Tow Placed (ATP, also known as Fiber Placement) laminates are compared to conventional tape layup manufacturing. Previous tensile fracture tests on fiber placed laminates show an improvement in tensile fracture of large notches over 20 percent compared to tape layup laminates. A hierarchial modeling scheme is presented. In this scheme, a global model is developed for laminates with notches. A local model is developed to study the influence of inhomogeneities at the notch tip, which are a consequence of the fiber placement manufacturing technique. In addition, a stacked membrane model was developed to study delaminations and splitting on a ply-by-ply basis. The results indicate that some benefit with respect to tensile fracture (up to 11 percent) can be gained from inhomogeneity alone, but that the most improvement may be obtained with splitting and delaminations which are more severe in the case of fiber placement compared to tape layup. Improvements up to 36 percent were found from the model for fiber placed laminates with damage at the notch tip compared to conventional tape layup.

  4. Full Scale Wind Tunnel and Seaplane Tow Channel

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Construction progress, Full Scale exit cone looking south from entrance cone, east switchboard, west switchboard, wind vanes at north end looking north through entrance cone, north end looking south through entrance cone, entrance cone looking north from exit cone, wind vanes south end of west exit cone, wind vanes south end of east exit cone, Tow Channel trolley lines looking north, east and west incline braces at north end. Full-Scale Tunnel (FST) exit cone construction and installation of fan motors. Smith DeFrance describes the entrance cone in NACA TR 459 as follows: 'Forward of the propellers and located on the center line of the tunnel is a smooth fairing which transforms the somewhat elliptic section of the single passage into two circular ones at the propellers. From the propellers aft, the exit cone is divided into two passages and each transforms in the length of 132 feet from a 35-foot 61/2-inch circular section to a 46-foot square. The included angle between the sides of each passage is 6 inches.' (p. 293)

  5. An experimental study of dynamics of towed flexible cylinders

    NASA Astrophysics Data System (ADS)

    Kheiri, M.; Païdoussis, M. P.; Amabili, M.

    2015-07-01

    In this paper, some experiments are described which were designed to illustrate the dynamical behaviour of towed flexible cylinders and to test the theory. A silicone rubber cylinder was manufactured such that it was almost neutrally buoyant when immersed in water. The cylinder was terminated by plexiglas end-pieces and was held in horizontal water flow by a length of nylon thread (towrope). Video capturing along with image processing techniques were used to measure the transverse displacement of the cylinder in the horizontal plane. For the cylinder with relatively streamlined nose and tail end-pieces, non-flexural (rigid-body), as well as flexural instabilities developed as the flow velocity was increased; shortening the towrope was not very effective for stabilizing the system, but a sufficiently blunt tail end-piece had a very significant stabilizing effect. The experimental observations are generally in qualitative agreement with the available nonlinear theory. Quantitative comparison of various quantities, e.g. the instability thresholds, between experiment and theory, based on the estimated values of some of the theoretical nondimensional parameters, is also fairly good.

  6. Design and Manufacture of Elastically Tailored Tow Placed Plates

    NASA Technical Reports Server (NTRS)

    Tatting, Brain F.; Guerdal, Zafer; Jegley, Dawn (Technical Monitor)

    2002-01-01

    Elastic stiffness tailoring of laminated composite panels by allowing the fibers to curve within the plane of the laminate is a relatively novel design concept that has been demonstrated to be both beneficial and practical. In particular, for structures with highly non-uniform stress states, such as the case of a flat panel with a central hole subjected to in-plane loading, the concept is likely to provide substantial improvements in load carrying capability. The objective of the present study is to determine the effectiveness of stiffness tailoring through the use of curvilinear fibers to reduce stress concentrations around the hole and improve the load carrying capability of panels with holes. In this study software was created that translates standard finite element models with traditional laminate definitions into ones that possess stacking sequences with curvilinear fiber paths that are directly manufacturable using an advanced tow placement machine. Preliminary designs for the manufacturing and testing phase were determined through rudimentary design studies for flat plates without holes under axial compression. These candidate designs were then analyzed using finite element models that accurately reflect the test conditions and geometries in order to select final designs for testing. A total of six large panels, measuring three feet by six feet, each of which are used to produce four specimens with or without holes, were fabricated and delivered to NASA for machining and testing.

  7. A Tow-Level Progressive Damage for Simulating Carbon-Fiber Textile Composites: Interim Report

    SciTech Connect

    Zywicz, E.

    2000-07-01

    A numerical approach to model the elasto-plastic and tensile damage response of tri-axially braided carbon-fiber polymeric-matrix composites is developed. It is micromechanically based and consists of a simplified unit cell geometry, a plane-stress tow-level constitutive relationship, a one-dimensional undulation constitutive law, and a non-traditional shell element integration rule. The braided composite lamina is idealized as periodic in the plane, and a simplified three-layer representative volume (RV) is assembled from axial and braider tows and pure resin regions. The constituents in each layer are homogenized with an iso-strain assumption in the fiber-direction and an iso-stress condition in the other directions. In the upper and lower layers, the fiber-direction strain is additively decomposed into an undulation and a tow portion. A finite-deformation tow model predicts the plane-stress tow response and is coupled to the undulation constitutive relationship. The overall braid model is implemented in DYNA3D and works with traditional shell elements. The finite-deformation tow constitutive relationship is derived from the fiber elasticity and the isotropic elasto-plastic power-law hardening matrix response using a thermodynamic framework and simple homogenization assumptions. The model replicates tensile damage evolution, in a smeared sense, parallel and perpendicular to the fiber axis and is regularized to yield mesh independent results. The tow-level model demonstrates reasonable agreement, prior to damage, with detailed three-dimensional FE (finite element) elasto-plastic simulations of aligned, periodically arranged, uni-directional composites. The 3-layer braid model response is compared with predictions obtained from detailed micromechanical simulations of the braid's unit cell in uni-axial extension, shear, and flexure for three braid angles. The elastic properties show good agreement as does the non-linear response for loadings dominated by the axial

  8. Kokkos Array

    Energy Science and Technology Software Center (ESTSC)

    2012-09-12

    The Kokkos Array library implements shared-memory array data structures and parallel task dispatch interfaces for data-parallel computational kernels that are performance-portable to multicore-CPU and manycore-accelerator (e.g., GPGPU) devices.

  9. A new ^3He-^129Xe Co-magnetometer using a Ramsey measurement sequence and Rb-K magnetometer for spin detection

    NASA Astrophysics Data System (ADS)

    Kabcenell, Aaron; Kominis, Iannis; Romalis, Michael

    2012-06-01

    Noble gas co-magnetometers have been used for many precision measurements, but their sensitivity is still very far from fundamental limits. We are exploring a new approach for operation of a ^3He-^129Xe co-magnetometer that uses a sensitive Rb-K magnetometer as a spin detector. By placing the noble gas atoms inside the magnetometer cell we can increase their magnetic signal using the Fermi-contact interaction, representing a gain of nearly 500 for ^129Xe, and achieve nearly quantum-noise limited detection of nuclear spins. In order to take advantage of the long coherence times of ^3He and^129Xe, the precession measurement is based on the Ramsey method of separated oscillatory fields and will be performed in an alkali-metal-free volume. The gas is then transported to the spin detector using techniques developed for remote NMR detection. The sensitivity of this approach is estimated to be on the order of 10-13 Hz/day^1/2, making it several orders of magnitude more sensitive than the best existing co-magnetometers. We are currently performing tests of the Ramsey measurement method and the sensitivity of the spin detector.

  10. Highly sensitive anisotropic magnetoresistance magnetometer for Eddy-current nondestructive evaluation.

    PubMed

    He, D F; Tachiki, M; Itozaki, H

    2009-03-01

    Using a commercially available anisotropic magnetoresistance (AMR) sensor of HMC1001, we developed a sensitive magnetometer. It could operate in amplifier mode or feedback mode. The magnetic field sensitivity of the AMR sensor was about 3.2 mV/V G. When the AMR sensor was biased by a voltage of 24 V, the magnetic field resolutions of the AMR magnetometer were about 12 pT/square root(Hz) at 1 kHz and 20 pT/square root(Hz) at 100 Hz. We used the AMR magnetometer for Eddy-current nondestructive evaluation in unshielded environment. PMID:19334957

  11. Freedom Star tows a barge with an SLWT into Port Canaveral for the first time

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Freedom Star, one of NASA's two solid rocket booster recovery ships, tows a barge containing the third Space Shuttle super lightweight external tank (SLWT) into Port Canaveral. This SLWT will be used to launch the orbiter Discovery on mission STS-95 in October. This first-time towing arrangement, part of a cost savings plan by NASA to prudently manage existing resources, began June 12 from the Michoud Assembly Facility in New Orleans where the Shuttle's external tanks are manufactured. The barge will now be transported up the Banana River to the LC-39 turn basin using a conventional tugboat. Previously, NASA relied on an outside contractor to provide external tank towing services at a cost of about $120,000 per trip. The new plan allows NASA's Space Flight Operations contractor, United Space Alliance (USA), to provide the same service directly to NASA using the recovery ships during their downtime between Shuttle launches. Studies show a potential savings of about $50,000 per trip. The cost of the necessary ship modifications should be paid back by the fourteenth tank delivery. The other recovery ship, Liberty Star, has also undergone deck strengthening enhancements and will soon have the necessary towing winch installed. The other recovery vessel, Liberty Star, has undergone deck strengthening enhancements along with Freedom Star and will soon have the necessary towing winch installed.

  12. A Model for Tow Impregnation and Consolidation for Partially Impregnated Thermoset Prepregs

    SciTech Connect

    John J. Gangloff Jr; Shatil Sinha; Suresh G. Advani

    2011-05-23

    The formation and transport of voids in composite materials remains a key research area in composite manufacturing science. Knowledge of how voids, resin, and fiber reinforcement propagate throughout a composite material continuum from green state to cured state during an automated tape layup process is key to minimizing defects induced by void-initiated stress concentrations under applied loads for a wide variety of composite applications. This paper focuses on modeling resin flow in a deforming fiber tow during an automated process of partially impregnated thermoset prepreg composite material tapes. In this work, a tow unit cell based model has been presented that determines the consolidation and impregnation of a thermoset prepreg tape under an input pressure profile. A parametric study has been performed to characterize the behavior of varying tow speed and compaction forces on the degree of consolidation. Results indicate that increased tow consolidation is achieved with slower tow speeds and higher compaction forces although the relationship is not linear. The overall modeling of this project is motivated to address optimization of the 'green state' composite properties and processing parameters to reduce or eliminate 'cured state' defects, such as porosity and de-lamination. This work is partially funded by the Department of Energy under Award number DE-EE0001367.

  13. Systolic arrays

    SciTech Connect

    Moore, W.R.; McCabe, A.P.H.; Vrquhart, R.B.

    1987-01-01

    Selected Contents of this book are: Efficient Systolic Arrays for the Solution of Toeplitz Systems, The Derivation and Utilization of Bit Level Systolic Array Architectures, an Efficient Systolic Array for Distance Computation Required in a Video-Codec Based Motion-Detection, On Realizations of Least-Squares Estimation and Kalman Filtering by Systolic Arrays, and Comparison of Systolic and SIMD Architectures for Computer Vision Computations.

  14. Nanocylinder arrays

    DOEpatents

    Tuominen, Mark; Schotter, Joerg; Thurn-Albrecht, Thomas; Russell, Thomas P.

    2007-03-13

    Pathways to rapid and reliable fabrication of nanocylinder arrays are provided. Simple methods are described for the production of well-ordered arrays of nanopores, nanowires, and other materials. This is accomplished by orienting copolymer films and removing a component from the film to produce nanopores, that in turn, can be filled with materials to produce the arrays. The resulting arrays can be used to produce nanoscale media, devices, and systems.

  15. Nanocylinder arrays

    DOEpatents

    Tuominen, Mark; Schotter, Joerg; Thurn-Albrecht, Thomas; Russell, Thomas P.

    2009-08-11

    Pathways to rapid and reliable fabrication of nanocylinder arrays are provided. Simple methods are described for the production of well-ordered arrays of nanopores, nanowires, and other materials. This is accomplished by orienting copolymer films and removing a component from the film to produce nanopores, that in turn, can be filled with materials to produce the arrays. The resulting arrays can be used to produce nanoscale media, devices, and systems.

  16. Monitoring tidal currents with a towed ADCP system

    NASA Astrophysics Data System (ADS)

    Sentchev, Alexei; Yaremchuk, Max

    2016-01-01

    The tidal circulation in the semi-enclosed Boulogne harbour (eastern English Channel) is measured during the various stages of the tidal cycle with a low-cost towed Acoustic Doppler Current Profiler (ADCP) system for the first time. The system is equipped with an interpolation algorithm which allows reconstructing space-time evolution of the velocity field for surveys whose duration is comparable or larger than the typical time of tidal variation (1-2 h). The method employs space-time velocity covariances derived from a numerical simulation of the surveyed area by a high-resolution relocatable model "Model for Applications on Regional Scale" (MARS). The covariances are utilized by the optimal interpolation algorithm to obtain the most likely evolution of the velocity field under the constraints provided by the ADCP observations and their error statistics. Technically, the MARS model run provides the first guess (background) evolution of the velocity field in the surveyed area which is then corrected by the data in a statistically consistent manner as it explicitly takes into the account both observational and modeling errors. The quality of the velocity reconstruction was validated against independent bottom-mounted ADCP data, the background model evolution, and against the results of spatial interpolation by Kriging technique. All tests demonstrated significant (30 to 60 %) reduction of the model-data misfit for the velocity field obtained as a result of space-time optimal interpolation. Although the method was applied to recover surface circulation, it can be extended for assessment of the full 4D tidal flow dynamics using the data recorded throughout the entire water column.

  17. Full Scale Tunnel (FST) and Seaplane Tow Channel

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Aerial and ground views of the overall construction of Full-Scale Tunnel (FST) and the Seaplane Tow Channel. In November 1929, Smith DeFrance submitted his recommendations for the general design of the Full Scale Wind Tunnel. The last on his list concerned the division of labor required to build this unusual facility. He believed the job had five parts and described them as follows: 'It is proposed that invitations be sent out for bids on five groups of items. The first would be for one contract on the complete structure; second the same as first, including the erection of the cones but not the fabrication, since this would be more of a shipyard job; third would cover structural steel, cover, sash and doors, but not cones or foundation; fourth, foundations; an fifth, fabrication of cones.' DeFrance's memorandum prompted the NACA to solicit estimates from a large number of companies. Preliminary designs and estimates were prepared and submitted to the Bureau of the Budget and Congress appropriated funds on February 20, 1929. The main construction contract with the J.A. Jones Company of Charlotte, North Carolina was signed one year later on February 12, 1930. It was a peculiar structure as the building's steel framework is visible on the outside of the building. DeFrance described this in NACA TR No. 459: 'The entire equipment is housed in a structure, the outside walls of which serve as the outer walls of the return passages. The over-all length of the tunnel is 434 feet 6 inches, the width 222 feet, and the maximum height 97 feet. The framework is of structural steel....' (pp. 292-293). Ground shots of work in progress, aerials of east area.

  18. Full Scale Wind Tunnel and Seaplane Tow Channel

    NASA Technical Reports Server (NTRS)

    1931-01-01

    Construction progress, studding in Tow Channel office area, Full Scale motor fairing in west exit cone, motor fairing in east exit cone. Propeller and motor fairing for west exit cone. Smith DeFrance described the propellers and motors in NACA TR No. 459. ' The propellers are located side by side and 48 feet aft of the throat of the exit-cone bell. The propellers are 35 feet 5 inches in diameter and each consists of four cast aluminum alloy blades screwed into a cast steel hub.' 'The most commonly used power plant for operating a wind tunnel is a direct-current motor and motor-generator set with Ward Leonard control system. For the full-scale wind tunnel it was found that alternating current slip-ring induction motors, together with satisfactory control equipment, could be purchased for approximately 30 percent less than the direct-current equipment. Two 4,000-horsepower slip-ring induction motors with 24 steps of speed between 75 and 300 r.p.m. were therefore installed. In order to obtain the range of speed one pole change was provided and the other variations are obtained by the introduction of resistance in the rotor circuit. This control permits a variation in air speed from 25 to 118 miles per hour. The two motors are connected through an automatic switchboard to one drum-type controller located in the test chamber. All the control equipment is interlocked and connected through time-limit relays, so that regardless of how fast the controller handle is moved the motors will increase in speed at regular intervals.' (p. 294-295)

  19. Relativistic electron acceleration by compressional-mode ULF waves: Evidence from correlated Cluster, Los Alamos National Laboratory spacecraft, and ground-based magnetometer measurements

    NASA Astrophysics Data System (ADS)

    Tan, Lun C.; Shao, X.; Sharma, A. S.; Fung, Shing F.

    2011-07-01

    Simultaneous observations by Cluster and Los Alamos National Laboratory (LANL) spacecraft and Canadian Array for Real-Time Investigations of Magnetic Activity and International Monitor for Auroral Geomagnetic Effects magnetometer arrays during a sudden storm commencement on 25 September 2001 show evidence of relativistic electron acceleration by compressional-mode ULF waves. The waves are driven by the quasiperiodic solar wind dynamical pressure fluctuations that continuously buffet the magnetosphere for ˜3 h. The compressional-mode ULF waves are identified by comparing the power of magnetic field magnitude fluctuations with the total magnetic field power. The radial distribution and azimuthal propagation of both toroidal and poloidal-mode ULF waves are derived from ground-based magnetometer data. The energetic electron fluxes measured by LANL show modulation of low-energy electrons and acceleration of high-energy electrons by the compressional poloidal-mode electric field oscillations. The energy threshold of accelerated electrons at the geosynchronous orbit is ˜0.4 MeV, which is roughly consistent with drift-resonant interaction of magnetospheric electrons with compressional-mode ULF waves.

  20. Time step size and model stiffness in the simulated slew of a tow of square sails

    NASA Astrophysics Data System (ADS)

    Greschik, Gyula

    2011-12-01

    In order to assess space tow solar sail stability and control feasibility, slew simulations are performed for a simplified but dynamically representative km-class tow-like sail of sixteen 25 m square units (10,000 m 2 total area and 110 kg gross mass) with a 250 kg payload. It is seen that, for the dimensions considered, the space tow concept is structurally sound and its control is feasible. While observed instabilities are identified as numeric in nature and are eliminated accordingly, their very occurrence highlights the need for a refinement of the model for future studies. The analyses are carried out with custom software implementing non-standard implicit-iterative time integration with innovative elements. A new damping model, specifically tailored for the analysis of truly gossamer systems such as solar sails, is also proposed.

  1. CLUSTER-STAFF search coil magnetometer calibration - comparisons with FGM

    NASA Astrophysics Data System (ADS)

    Robert, P.; Cornilleau-Wehrlin, N.; Piberne, R.; de Conchy, Y.; Lacombe, C.; Bouzid, V.; Grison, B.; Alison, D.; Canu, P.

    2014-09-01

    The main part of the Cluster Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment consists of triaxial search coils allowing the measurements of the three magnetic components of the waves from 0.1 Hz up to 4 kHz. Two sets of data are produced, one by a module to filter and transmit the corresponding waveform up to either 10 or 180 Hz (STAFF-SC), and the second by the onboard Spectrum Analyser (STAFF-SA) to compute the elements of the spectral matrix for five components of the waves, 3 × B and 2 × E (from the EFW experiment), in the frequency range 8 Hz to 4 kHz. In order to understand the way the output signals of the search coils are calibrated, the transfer functions of the different parts of the instrument are described as well as the way to transform telemetry data into physical units across various coordinate systems from the spinning sensors to a fixed and known frame. The instrument sensitivity is discussed. Cross-calibration inside STAFF (SC and SA) is presented. Results of cross-calibration between the STAFF search coils and the Cluster Fluxgate Magnetometer (FGM) data are discussed. It is shown that these cross-calibrations lead to an agreement between both data sets at low frequency within a 2% error. By means of statistics done over 10 yr, it is shown that the functionalities and characteristics of both instruments have not changed during this period.

  2. Micromachined magnetometer-accelerometer for a navigation system

    NASA Astrophysics Data System (ADS)

    Cho, Ji-Man; Kim, Kyung S.; An, Seungdo; Park, HoJoon; Hahm, Ghun

    2002-11-01

    A new type of magnetometer-accelerometer is developed with a silicon micromachining. The operation principle of the sensor is based on the well known Lorentz force caused by the interaction of a current and an external magnetic field on a suspended conducting beam. To realize a new resonant micro sensor detecting both acceleration and the geomagnetic field simultaneously, a conducting line is formed on a spring part of a silicon accelerometer having two mass plates. And a new Samsung MEMS fabrication process is developed for this sensor. The process uses a silicon-on-glass (SOG) wafer, an inverted SOG wafer, and a gold-silicon eutectic bonding for the wafer-level hermetic packaging. To operate the sensor, an ac current of its mechanical resonant frequency is driven through the conducting line. Totally 1 mW is consumed in the current driving element. This newly developed sensor is enough for the 10 degree electronic display of the orientation angle and can be used in a portable navigator such as SmartPhones and PDAs that need a small, low cost and low power electronic compass.

  3. Multilayer MgB2 superconducting quantum interference filter magnetometers

    NASA Astrophysics Data System (ADS)

    Galan, Elias; Melbourne, Thomas; Davidson, Bruce A.; Xi, X. X.; Chen, Ke

    2016-04-01

    We report two types of all-MgB2 superconductive quantum interference filter (SQIF) magnetometers that can measure absolute magnetic fields with high sensitivity. In one configuration, the SQIFs were made of 20 multilayer nonplanar all-MgB2 superconducting quantum interference devices (SQUIDs) connected in parallel with loop areas ranging in size from 0.4 to 3.6 μm2. These devices are sensitive to magnetic fields parallel to the substrate and show a single antipeak from 3 to 16 K with a maximum transfer function of ˜16 V/T at 3 K and a field noise of ˜110 pT/Hz1/2 above 100 Hz at 10 K. In a second configuration, the SQIFs were made with 16 planar SQUIDs connected in parallel with loop areas ranging in size from 4 μm2 to 25 μm2 and are sensitive to the magnetic fields perpendicular to the substrate. The planar SQIF shows a single antipeak from 10 to 22 K with a maximum transfer function of 7800 V/T at 10 K and a field noise of ˜70 pT/Hz1/2 above 100 Hz at 20 K.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Ultra-sensitive magnetic microscopy with an optically pumped magnetometer

    DOE PAGESBeta

    Kim, Young Jin; Savukov, Igor Mykhaylovich

    2016-04-22

    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 devicemore » can achieve a unique combination of high resolution (80 μm) and high sensitivity (8.1 pT/). Additionally, 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.« less

  6. Lunar magnetic anomalies detected by the Apollo subsatellite magnetometers

    NASA Technical Reports Server (NTRS)

    Hood, L. L.; Coleman, P. J., Jr.; Russell, C. T.; Wilhelms, D. E.

    1979-01-01

    Properties of lunar crustal magnetization thus far deduced from Apollo subsatellite magnetometer data are reviewed using two of the most accurate available magnetic anomaly maps, one covering a portion of the lunar near side and the other a part of the far side. The largest single anomaly found within the region of coverage on the near-side map correlates exactly with a conspicuous light-colored marking in western Oceanus Procellarum called Reiner Gamma. This feature is interpreted as an unusual deposit of ejecta from secondary craters of the large nearby primary impact crater Cavalerius. The mean altitude of the far-side anomaly gap is much higher than that of the near side map and the surface geology is more complex; individual anomaly sources have therefore not yet been identified. The mechanism of magnetization and the origin of the magnetizing field remain unresolved, but the uniformity with which the Reiner Gamma deposit is apparently magnetized, and the north-south depletion of magnetization intensity across a substantial portion of the far side, seem to require the existence of an ambient field, perhaps of global or larger extent.

  7. Pulsed field magnetometer for nondestructive monitoring of encapsulated magnetic materials

    NASA Astrophysics Data System (ADS)

    Rothwarf, F.; Simizu, S.; Huang, M. Q.; Schaefer, R. J.

    1993-05-01

    A study was recently undertaken to consolidate Sm2Fe17N3-x-based materials by hot isostatic pressing (HIPing). For HIPing, pressed green samples were placed at the center of evacuated, closely fitting, nonmagnetic, thin-walled, stainless-steel cans. The use of nonmagnetic, high-resistivity containers for the samples offered a unique opportunity to evaluate the magnetic properties of the samples after HIPing, without removing them from the HIP cans, by using a pulsed field magnetometer (PFM). The high electrical resistivity of the samples and their containers permits the slowly varying magnetic field (˜5 ms rise time, 45 ms pulse length) to penetrate a sample fully with no phase lags. Thus, the magnetization of a sample is essentially in equilibrium with the applied, time-varying magnetic field. With this method, a given set of encapsulated samples could be subjected to successively higher temperature heat treatments to determine their effects on the magnetic properties. The PFM allowed the rapid acquisition, storage, and processing of digital data by computer. The design of the PFM system, demagnetization corrections, procedures used, and some results are presented.

  8. CLUSTER STAFF search coils magnetometer calibration - comparisons with FGM

    NASA Astrophysics Data System (ADS)

    Robert, P.; Cornilleau-Wehrlin, N.; Piberne, R.; de Conchy, Y.; Lacombe, C.; Bouzid, V.; Grison, B.; Alison, D.; Canu, P.

    2013-12-01

    The main part of Cluster Spatio Temporal Analysis of Field Fluctuations (STAFF) experiment consists of triaxial search coils allowing the measurements of the three magnetic components of the waves from 0.1 Hz up to 4 kHz. Two sets of data are produced, one by a module to filter and transmit the corresponding waveform up to either 10 or 180 Hz (STAFF-SC) and the second by an onboard Spectrum Analyser (STAFF-SA) to compute the elements of the spectral matrix for five components of the waves, 3 × B and 2 × E (from EFW experiment) in the frequency range 8 Hz to 4 kHz. In order to understand the way the output signal of the search coils are calibrated, the transfer functions of the different parts of the instrument are described as well as the way to transform telemetry data into physical units, across various coordinate systems from the spinning sensors to a fixed and known frame. The instrument sensitivity is discussed. Cross-calibration inside STAFF (SC and SA) is presented. Results of cross-calibration between the STAFF search coils and the Cluster Flux Gate Magnetometer (FGM) data are discussed. It is shown that these cross-calibrations lead to an agreement between both data sets at low frequency within a 2% error. By means of statistics done over 10 yr, it is shown that the functionalities and characteristics of both instruments have not changed during this period.

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

    PubMed

    Kim, Young Jin; Savukov, Igor

    2016-01-01

    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. PMID:27103463

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    Kim, Young Jin; Savukov, Igor

    2016-01-01

    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. PMID:27103463

  12. Atomic magnetometer-based ultra-sensitive magnetic microscopy

    NASA Astrophysics Data System (ADS)

    Kim, Young Jin; Savukov, Igor

    2016-03-01

    An atomic magnetometer (AM) based on lasers and alkali-metal vapor cells is currently the most sensitive non-cryogenic magnetic-field sensor. Many applications in neuroscience and other fields require high resolution, high sensitivity magnetic microscopic measurements. In order to meet this need we combined a cm-size spin-exchange relaxation-free AM with a flux guide (FG) to produce an ultra-sensitive FG-AM magnetic microscope. The FG serves to transmit the target magnetic flux to the AM thus enhancing both the sensitivity and resolution for tiny magnetic objects. In this talk, we will describe a prototype FG-AM device and present experimental and numerical tests of its sensitivity and resolution. We also demonstrate that an optimized FG-AM achieves high resolution and high sensitivity sufficient to detect a magnetic field of a single neuron in a few seconds, which would be an important milestone in neuroscience. We anticipate that this unique device can be applied to the detection of a single neuron, the detection of magnetic nano-particles, which in turn are very important for detection of target molecules in national security and medical diagnostics, and non-destructive testing.

  13. Performance of high-TC dc SQUID magnetometers for use in a magnetically disturbed environment

    NASA Astrophysics Data System (ADS)

    Kim, I. S.; Yu, K. K.; Lee, Y. H.; Kim, K. W.; Park, Y. K.

    2004-06-01

    YBCO dc SQUID magnetometers based on bicrystal Josephson junctions on 10 mm × 10 mm STO substrates have been fabricated. We have designed three different types of pickup coils for the SQUID magnetometers, i.e., solid-type, 12 and 16 parallel loops with 50 m line width to test performances of the SQUIDs for use in a magnetically disturbed environment. Magnetometer with 16-parallel-loop pickup coil exhibit most stable FLL operation under external dc magnetic field. Finally, we could obtain optimised direct coupled YBCO SQUID magnetometer design having flux transfer coefficient B of 4.5 nT/0 and magnetic field noise BN of 30 fT/Hz1/2 measured at 100 Hz.

  14. Novel Handheld Magnetometer Probe Based on Magnetic Tunnelling Junction Sensors for Intraoperative Sentinel Lymph Node Identification

    PubMed Central

    Cousins, A.; Balalis, G. L.; Thompson, S. K.; Forero Morales, D.; Mohtar, A.; Wedding, A. B.; Thierry, B.

    2015-01-01

    Using magnetic tunnelling junction sensors, a novel magnetometer probe for the identification of the sentinel lymph node using magnetic tracers was developed. Probe performance was characterised in vitro and validated in a preclinical swine model. Compared to conventional gamma probes, the magnetometer probe showed excellent spatial resolution of 4.0 mm, and the potential to detect as few as 5 μg of magnetic tracer. Due to the high sensitivity of the magnetometer, all first-tier nodes were identified in the preclinical experiments, and there were no instances of false positive or false negative detection. Furthermore, these preliminary data encourage the application of the magnetometer probe for use in more complex lymphatic environments, such as in gastrointestinal cancers, where the sentinel node is often in close proximity to other non-sentinel nodes, and high spatial resolution detection is required. PMID:26038833

  15. Novel handheld magnetometer probe based on magnetic tunnelling junction sensors for intraoperative sentinel lymph node identification.

    PubMed

    Cousins, A; Balalis, G L; Thompson, S K; Forero Morales, D; Mohtar, A; Wedding, A B; Thierry, B

    2015-01-01

    Using magnetic tunnelling junction sensors, a novel magnetometer probe for the identification of the sentinel lymph node using magnetic tracers was developed. Probe performance was characterised in vitro and validated in a preclinical swine model. Compared to conventional gamma probes, the magnetometer probe showed excellent spatial resolution of 4.0 mm, and the potential to detect as few as 5 μg of magnetic tracer. Due to the high sensitivity of the magnetometer, all first-tier nodes were identified in the preclinical experiments, and there were no instances of false positive or false negative detection. Furthermore, these preliminary data encourage the application of the magnetometer probe for use in more complex lymphatic environments, such as in gastrointestinal cancers, where the sentinel node is often in close proximity to other non-sentinel nodes, and high spatial resolution detection is required. PMID:26038833

  16. Ultra-sensitive high-density Rb-87 radio-frequency magnetometer

    SciTech Connect

    Savukov, I.; Boshier, M. G.; Karaulanov, T.

    2014-01-13

    Radio-frequency (RF) atomic magnetometers (AMs) can be used in many applications, such as magnetic resonance imaging and nuclear quadrupole resonance. High-density AMs provide both superior sensitivity and large bandwidth. Previously, high-density potassium AMs were demonstrated, but these magnetometers have various disadvantages, such as high-temperature of operation and bulky design. We demonstrate a rubidium-87 RF AM with 5 fT/Hz{sup 1/2} sensitivity (3 fT Hz{sup 1/2} probe noise), which is comparable to that of the best potassium magnetometers. Our magnetometer also features a simple fiber-optic design, providing maximum flexibility for magnetic-field measurements.

  17. Study of earthquakes and related phenomena using a satellite scalar magnetometer

    NASA Astrophysics Data System (ADS)

    Schwingenschuh, Konrad; Magnes, Werner; Xuhui, Shen; Wang, Jindong; Pollinger, Andreas; Hagen, Christian; Lammegger, Roland; Ellmeier, Michaela; Prattes, Gustav; Eichelberger, Hans-Ulrich; Wolbang, Daniel; Boudjada, Mohammed Y.; Besser, Bruno P.; Rozhnoi, Alexander A.; Zhang, Tielong

    2016-04-01

    A new type of scalar magnetometer for space applications has been developed (see Lammegger 2008). A first instrument of this type will be flown aboard the upcoming Chinese Seismo-Electromagnetic Satellite (CSES). The scalar magnetometer can measure the total magnetic field with an accuracy of about 50 pT/sqrt(Hz) in the frequency range between 0 and 30 Hz. In order to minimize the stray field of the satellite, the sensor of the scalar magnetometer is mounted at the tip of a five meter boom. The main scientific objective of the scalar magnetometer aboard the Chinese satellite is the investigation of seismic phenomena before, during and after earthquakes or volcanic activity. The expected variations of the total magnetic field above seismic active regions, are presented, using a model based on the groundbased tectonomagnetic measurements and are simplified lithospheric-ionospheric coupling coefficient. Patent: Lammegger, R., WO 2008/151344 A3, Method and Device for Measuring Magnetic Fields

  18. Solid-State Multimission Magnetometer (SSM(3)): Application to Groundwater Exploration on Mars

    NASA Technical Reports Server (NTRS)

    Grimm, Robert E.

    2002-01-01

    This report describes work to develop solid-state magnetometers using magnetoresistive thin films, low-frequency electric-field measurements, and methods for electromagnetic detection of water and ice in the subsurface of Mars.

  19. 46 CFR 27.301 - What are the requirements for fire pumps, fire mains, and fire hoses on towing vessels?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false What are the requirements for fire pumps, fire mains... the requirements for fire pumps, fire mains, and fire hoses on towing vessels? By April 29, 2005, you must provide for your towing vessel either a self-priming, power-driven, fixed fire-pump, a fire...

  20. 46 CFR 27.301 - What are the requirements for fire pumps, fire mains, and fire hoses on towing vessels?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false What are the requirements for fire pumps, fire mains... the requirements for fire pumps, fire mains, and fire hoses on towing vessels? By April 29, 2005, you must provide for your towing vessel either a self-priming, power-driven, fixed fire-pump, a fire...