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Sample records for field ii source

  1. Kr II and Xe II axial velocity distribution functions in a cross-field ion source

    Science.gov (United States)

    Lejeune, A.; Bourgeois, G.; Mazouffre, S.

    2012-07-01

    Laser induced fluorescence measurements were carried out in a cross-field ion source to examine the behaviour of the axial ion velocity distribution functions (VDFs) in the expanding plasma. In the present paper, we focus on the axial VDFs of Kr II and Xe II ions. We examine the contourplots in a 1D-phase space (x,vx) representation in front of the exhaust channel and along the centerline of the ion source. The main ion beam, whose momentum corresponds to the ions that are accelerated through the whole potential drop, is observed. A secondary structure reveals the ions coming from the opposite side of the channel. We show that the formation of the neutralized ion flow is governed by the annular geometry. The assumption of a collisionless shock or a double layer due to supersonic beam interaction is not necessary. A non-negligible fraction of slow ions originates in local ionization or charge-exchange collision events between ions of the expanding plasma and atoms of the background residual gas. Slow ions that are produced near the centerline in the vicinity of the exit plane are accelerated toward the source body with a negative velocity leading to a high sputtering of front face. On the contrary, the ions that are produced in the vicinity of the channel exit plane are partially accelerated by the extended electric field.

  2. 3D-MHD simulations of the evolution of magnetic fields in FR II radio sources

    CERN Document Server

    Huarte-Espinosa, Martin; Alexander, Paul

    2010-01-01

    3D-MHD numerical simulations of bipolar, hypersonic, weakly magnetized jets and synthetic synchrotron observations are presented to study the structure and evolution of magnetic fields in FR II radio sources. The magnetic field setup in the jet is initially random. The power of the jets as well as the observational viewing angle are investigated. We find that synthetic polarization maps agree with observations and show that magnetic fields inside the sources are shaped by the jets' backflow. Polarimetry statistics correlates with time, the viewing angle and the jet-to-ambient density contrast. The magnetic structure inside thin elongated sources is more uniform than for ones with fatter cocoons. Jets increase the magnetic energy in cocoons, in proportion to the jet velocity. Both, filaments in synthetic emission maps and 3D magnetic power spectra suggest that turbulence develops in evolved sources.

  3. Integral field spectroscopy of the ultraluminous X-ray source Holmberg II X-1

    CERN Document Server

    Lehmann, I; Fabrika, S; Roth, M; Miyaji, T; Afanasiev, V; Sholukhova, O; Sánchez, S F; Greiner, J; Hasinger, G; Costantini, E; Surkov, A; Burenkov, A

    2004-01-01

    We present optical integral field observations of the H II region containing the ultraluminous X-ray source Holmberg II X-1. We confirm the existence of an X-ray ionized nebula as the counterpart of the source due to the detection of an extended He II (4686A) region (21 x 47 pc) at the Chandra ACIS-S position. An extended blue objects with a size of 11 x 14 pc is coincident with the X-ray/He II region, which could indicate either a young stellar complex or a cluster. We have derived an X-ray to optical luminosity ratio of Lx/Lb>170, and presumable it is Lx/Lb~300-400 using the recent HST ACS data. We find a complex velocity dispersion at the position of the ULX. In addition, there is a radial velocity variation in the X-ray ionized region found in the He II emission of +-50 km/s on spatial scales of 2-3 arcsec. We believe that the putative black hole not only ionizes the surrounding HII gas, but also perturbs it dynamically (via jets or the accretion disk wind). The spatial analysis of the public Chandra ACIS...

  4. Three-dimensional magnetohydrodynamic simulations of the evolution of magnetic fields in Fanaroff-Riley class II radio sources

    CERN Document Server

    Huarte-Espinosa, Martin; Alexander, Paul

    2011-01-01

    Radio observations of Fanaroff-Riley class II sources often show correlations between the synchrotron emission and the linear-polarimetric distributions. Magnetic position vectors seem to align with the projected emission of both the radio jets and the sources' edges. Using statistics we study such relation as well as its unknown time evolution via synthetic polarisation maps of model FR II sources formed in 3D-MHD numerical simulations of bipolar, hypersonic and weakly magnetised jets. The magnetic field is initially random with a Kolmogorov power spectrum, everywhere. We investigate the structure and evolution of magnetic fields in the sources as a function of the power of jets and the observational viewing angle. Our synthetic polarisation maps agree with observations, showing B-field vectors which are predominantly aligned with the jet axis, and show that magnetic fields inside sources are shaped by the jets' backflow. Polarimetry is found to correlate with time, the viewing angle and the jet-to-ambient d...

  5. Point-source idealization in classical field theories. II. Mechanical energy losses from electromagnetic radiation reaction

    Science.gov (United States)

    Kates, Ronald E.; Rosenblum, Arnold

    1982-05-01

    This paper compares the mechanical energy losses due to electromagnetic radiation reaction on a two-particle, slow-motion system, as calculated from (1) the method of matched asymptotic expansions and (2) the Lorentz-Dirac equation, which assumes point sources. The matching derivation of the preceding paper avoided the assumption of a δ-function source by using Reissner-Nordström matching zones. Despite the differing mathematical assumptions of the two methods, their results are in agreement with each other and with the electromagnetic-field energy losses calculated by the evaluation of flux integrals. Our purpose is eventually to analyze Rosenblum's use of point sources as a possible cause of disagreement between the analogous calculations of gravitational radiation on a slow-motion system of two bodies. We begin with the simpler electromagnetic problem.

  6. Field emission electron source

    Science.gov (United States)

    Zettl, Alexander Karlwalter; Cohen, Marvin Lou

    2000-01-01

    A novel field emitter material, field emission electron source, and commercially feasible fabrication method is described. The inventive field emission electron source produces reliable electron currents of up to 400 mA/cm.sup.2 at 200 volts. The emitter is robust and the current it produces is not sensitive to variability of vacuum or the distance between the emitter tip and the cathode. The novel emitter has a sharp turn-on near 100 volts.

  7. Null-field radiationless sources.

    Science.gov (United States)

    Hurwitz, Elisa; Gbur, Greg

    2014-11-15

    It is shown that it is in principle possible to produce combined sources of polarization and magnetization that are not only radiationless but that have any (and sometimes several) of the four microscopic or macroscopic electromagnetic fields exactly zero. The conditions that such a "null-field radiationless source" must satisfy are derived, and examples are given for several cases. The implications for transformation optics and invisibility physics in general are discussed.

  8. Relativistic Hotspots in FR II Radio Sources

    Science.gov (United States)

    Chartrand, Alex M.; Miller, B. P.; Brandt, W. N.; Gawronski, M. P.; Cederbloom, S. E.

    2011-01-01

    We present a list of six FR II radio sources that are candidates to possess hotspots with modestly relativistic (v/c > 0.2) bulk velocities, in contrast to the vast majority of FR II radio sources that possess non-relativistic hotspot bulk velocities (e.g., v/c = 0.03+/- 0.02 from Scheuer 1995). These objects display arm- length and flux-ratio asymmetries between lobes that self-consistently indicate relativistic motion. The candidates are selected from the FIRST 1.4 GHz survey (including but not limited to the catalog of FR II quasars of de Vries et al. 2006) with the requirement that the radio core have a spectroscopic SDSS counterpart. We find no significant difference in the number of neighboring sources within 300 projected kpc of the candidate sources and randomly selected nearby regions. The deprojected and light travel-time corrected lobe distances are not abnormal for FR II sources, and neither are the core-to-lobe flux ratios after correcting for lobe beaming. We briefly consider four possibilities for these type of objects: (i) environmental interactions randomly mimicking relativistic effects, (ii) a restarted jet causing the near hotspot to brighten while the far hotspot still appears faint, (iii) observation during a short interval common to FR II lifetimes during which the hotspot decelerates from relativistic to non-relativistic velocities, and (iv) innately unusual characteristics (e.g., a mass-loaded jet) driving relativistic bulk velocities in the hotspots of a small fraction (< 1%) of FR II objects. We favor the last interpretation but cannot rule out the alternatives. We also comment on the useful external constraints such objects provide to the evaluation of hotspot X-ray emission mechanisms.

  9. A new laser vibrometry-based 2D selective intensity method for source identification in reverberant fields: part II. Application to an aircraft cabin

    Science.gov (United States)

    Revel, G. M.; Martarelli, M.; Chiariotti, P.

    2010-07-01

    The selective intensity technique is a powerful tool for the localization of acoustic sources and for the identification of the structural contribution to the acoustic emission. In practice, the selective intensity method is based on simultaneous measurements of acoustic intensity, by means of a couple of matched microphones, and structural vibration of the emitting object. In this paper high spatial density multi-point vibration data, acquired by using a scanning laser Doppler vibrometer, have been used for the first time. Therefore, by applying the selective intensity algorithm, the contribution of a large number of structural sources to the acoustic field radiated by the vibrating object can be estimated. The selective intensity represents the distribution of the acoustic monopole sources on the emitting surface, as if each monopole acted separately from the others. This innovative selective intensity approach can be very helpful when the measurement is performed on large panels in highly reverberating environments, such as aircraft cabins. In this case the separation of the direct acoustic field (radiated by the vibrating panels of the fuselage) and the reverberant one is difficult by traditional techniques. The work shown in this paper is the application of part of the results of the European project CREDO (Cabin Noise Reduction by Experimental and Numerical Design Optimization) carried out within the framework of the EU. Therefore the aim of this paper is to illustrate a real application of the method to the interior acoustic characterization of an Alenia Aeronautica ATR42 ground test facility, Alenia Aeronautica being a partner of the CREDO project.

  10. FIELD STRENGTH MEASUREMENTS, PHASE II.

    Science.gov (United States)

    The measurement of the strength of radio frequency fields at high frequency and above has followed practices which are standard for the measurement...of field strength at medium and low frequencies. Variability of measurements made in practical situations and a lack of reproducibility of...measurements made under apparently identical conditions has prompted an investigation of equipment and methods used in the determinations. The field strength

  11. Fields from point sources using the aperture field method

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1991-01-01

    It is shown that the field of arbitrary point sources can be found from the aperture field method. It is demonstrated that the exact result in the far field is easily obtained for an electric Hertzian dipole in free space.......It is shown that the field of arbitrary point sources can be found from the aperture field method. It is demonstrated that the exact result in the far field is easily obtained for an electric Hertzian dipole in free space....

  12. Gravitational Field Shielding by Scalar Field and Type II Superconductors

    Directory of Open Access Journals (Sweden)

    Zhang B. J.

    2013-01-01

    Full Text Available The gravitational field shielding by scalar field and type II superconductors are theoret- ically investigated. In accord with the well-developed five-dimensional fully covariant Kaluza-Klein theory with a scalar field, which unifies the Einsteinian general relativity and Maxwellian electromagnetic theory, the scalar field cannot only polarize the space as shown previously, but also flatten the space as indicated recently. The polariza- tion of space decreases the electromagnetic field by increasing the equivalent vacuum permittivity constant, while the flattening of space decreases the gravitational field by decreasing the equivalent gravitational constant. In other words, the scalar field can be also employed to shield the gravitational field. A strong scalar field significantly shield the gravitational field by largely decreasing the equivalent gravitational constant. According to the theory of gravitational field shielding by scalar field, the weight loss experimentally detected for a sample near a rotating ceramic disk at very low tempera- ture can be explained as the shielding of the Earth gravitational field by the Ginzburg- Landau scalar field, which is produced by the type II superconductors. The significant shielding of gravitational field by scalar field produced by superconductors may lead to a new spaceflight technology in future.

  13. The sources of our iron ores. II

    Science.gov (United States)

    Burchard, E.F.

    1933-01-01

    In this instalment** the iron ore deposits of the Lake Superior States, which normally furnish about 80 per cent, of the annual output of the United States, are described together with historical notes on discovery and transportation of ore. Deposits in the Mississippi Valley and Western States are likewise outlined and the sources of imported ore are given. Reviewing the whole field, it is indicated that the great producing deposits of the Lake Superior and southern Appalachian regions are of hematite in basin areas of sedimentary rocks, that hydrated iron oxides and iron carbonates are generally found in undisturbed comparatively recent sediments, and that magnetite occurs in metamorphic and igneous rocks; also that numerical abundance of deposits is not a criterion as to their real importance as a source of supply. Statistics of production of iron ore and estimates of reserves of present grade conclude the paper.

  14. Field ion source development for neutron generators

    Science.gov (United States)

    Bargsten Johnson, B.; Schwoebel, P. R.; Holland, C. E.; Resnick, P. J.; Hertz, K. L.; Chichester, D. L.

    2012-01-01

    An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption (˜20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with ˜10,000 tip arrays have achieved deuterium ion currents of ˜50 nA. Neutron production by field ionization has yielded ˜10 2 n/s from ˜1 mm 2 of array area using the deuterium-deuterium fusion reaction at 90 kV.

  15. Field ion source development for neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    Bargsten Johnson, B. [University of New Mexico, Albuquerque, NM 87131 (United States); Schwoebel, P.R., E-mail: schwoebel@chtm.unm.edu [University of New Mexico, Albuquerque, NM 87131 (United States); Holland, C.E. [SRI International, Menlo Park, CA 94025 (United States); Resnick, P.J. [Sandia National Laboratories, Albuquerque, NM 87123 (United States); Hertz, K.L. [Sandia National Laboratories, Livermore, CA 94551 (United States); Chichester, D.L. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

    2012-01-21

    An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption ({approx}20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with {approx}10,000 tip arrays have achieved deuterium ion currents of {approx}50 nA. Neutron production by field ionization has yielded {approx}10{sup 2} n/s from {approx}1 mm{sup 2} of array area using the deuterium-deuterium fusion reaction at 90 kV.

  16. Field Ion Source Development for Neutron Generators

    Energy Technology Data Exchange (ETDEWEB)

    B. Bargsten Johnson; P. R. Schwoebel; C. E. Holland; P. J. Resnick; K. L. Hertz; D. L. Chichester

    2012-01-01

    An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption ({approx}20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with {approx}10,000 tip arrays have achieved deuterium ion currents of {approx}50 nA. Neutron production by field ionization has yielded {approx}10{sup 2} n/s from {approx}1 mm{sup 2} of array area using the deuterium-deuterium fusion reaction at 90 kV.

  17. Laser ion source with solenoid field

    Science.gov (United States)

    Kanesue, Takeshi; Fuwa, Yasuhiro; Kondo, Kotaro; Okamura, Masahiro

    2014-11-01

    Pulse length extension of highly charged ion beam generated from a laser ion source is experimentally demonstrated. The laser ion source (LIS) has been recognized as one of the most powerful heavy ion source. However, it was difficult to provide long pulse beams. By applying a solenoid field (90 mT, 1 m) at plasma drifting section, a pulse length of carbon ion beam reached 3.2 μs which was 4.4 times longer than the width from a conventional LIS. The particle number of carbon ions accelerated by a radio frequency quadrupole linear accelerator was 1.2 × 1011, which was provided by a single 1 J Nd-YAG laser shot. A laser ion source with solenoid field could be used in a next generation heavy ion accelerator.

  18. Emittance of a Field Emission Electron Source

    Science.gov (United States)

    2010-01-05

    approximately correct. The gate and switching time A thermionic source is run space-charge limited for which the current varies as a power 3 /2 of the grid...and millimeter-wave power amplifiers that use thermionic cathodes, requiring the sources to produce a current density characteristic of that in the...Rb radius, magnetic field strength B, accelerating voltage Vb, frequency f inversely related to Rb, harmonic number n, and emit- tance via 1− J

  19. Tailed Radio Sources in the CDFS Field

    Indian Academy of Sciences (India)

    S. Dehghan; M. Johnston-Hollitt; M. Mao; R. P. Norris; N. A. Miller; M. Huynh

    2011-12-01

    Using 1.4 GHz ATCA & VLA images with 5.5 GHz ATCA data, we present a sample of 12 bent-tailed galaxies over the 4 deg2 area of the Chandra Deep Field South (CDFS). We find 10 new sources, one of which is possibly the highest red-shift bent-tailed galaxy detected at ∼ 2.

  20. TRIGA MARK-II source term

    Science.gov (United States)

    Usang, M. D.; Hamzah, N. S.; J. B., Abi M.; M. Z., M. Rawi; Abu, M. P.

    2014-02-01

    ORIGEN 2.2 are employed to obtain data regarding γ source term and the radio-activity of irradiated TRIGA fuel. The fuel composition are specified in grams for use as input data. Three types of fuel are irradiated in the reactor, each differs from the other in terms of the amount of Uranium compared to the total weight. Each fuel are irradiated for 365 days with 50 days time step. We obtain results on the total radioactivity of the fuel, the composition of activated materials, composition of fission products and the photon spectrum of the burned fuel. We investigate the differences of results using BWR and PWR library for ORIGEN. Finally, we compare the composition of major nuclides after 1 year irradiation of both ORIGEN library with results from WIMS. We found only minor disagreements between the yields of PWR and BWR libraries. In comparison with WIMS, the errors are a little bit more pronounced. To overcome this errors, the irradiation power used in ORIGEN could be increased a little, so that the differences in the yield of ORIGEN and WIMS could be reduced. A more permanent solution is to use a different code altogether to simulate burnup such as DRAGON and ORIGEN-S. The result of this study are essential for the design of radiation shielding from the fuel.

  1. TRIGA MARK-II source term

    Energy Technology Data Exchange (ETDEWEB)

    Usang, M. D., E-mail: mark-dennis@nuclearmalaysia.gov.my; Hamzah, N. S., E-mail: mark-dennis@nuclearmalaysia.gov.my; Abi, M. J. B., E-mail: mark-dennis@nuclearmalaysia.gov.my; Rawi, M. Z. M. Rawi, E-mail: mark-dennis@nuclearmalaysia.gov.my; Abu, M. P., E-mail: mark-dennis@nuclearmalaysia.gov.my [Bahagian Teknologi Reaktor, Agensi Nuklear Malaysia, 43000 Kajang (Malaysia)

    2014-02-12

    ORIGEN 2.2 are employed to obtain data regarding γ source term and the radio-activity of irradiated TRIGA fuel. The fuel composition are specified in grams for use as input data. Three types of fuel are irradiated in the reactor, each differs from the other in terms of the amount of Uranium compared to the total weight. Each fuel are irradiated for 365 days with 50 days time step. We obtain results on the total radioactivity of the fuel, the composition of activated materials, composition of fission products and the photon spectrum of the burned fuel. We investigate the differences of results using BWR and PWR library for ORIGEN. Finally, we compare the composition of major nuclides after 1 year irradiation of both ORIGEN library with results from WIMS. We found only minor disagreements between the yields of PWR and BWR libraries. In comparison with WIMS, the errors are a little bit more pronounced. To overcome this errors, the irradiation power used in ORIGEN could be increased a little, so that the differences in the yield of ORIGEN and WIMS could be reduced. A more permanent solution is to use a different code altogether to simulate burnup such as DRAGON and ORIGEN-S. The result of this study are essential for the design of radiation shielding from the fuel.

  2. Field mapping of ballistic pressure pulse sources

    Directory of Open Access Journals (Sweden)

    Rad Abtin Jamshidi

    2015-09-01

    Full Text Available Ballistic pressure pulse sources are used since late 1990s for the extracorporeal treatment of chronic Enthesitis. Newly indications are found in trigger-point-therapy for the treatment of musculoskeletal disorders. In both applications excellent results without relevant side effects were found in clinical trials. The technical principle of pressure pulse source is based on the same techniques used in air guns. A projectile is accelerated by pressurized air and hits the applicator with high kinetic energy. By this a compression wave travels through the material and induces a fast (4..5μs, almost singular pressure pulse of 2..10 MPa, which is followed by an equally short rarefaction phase of about the same amplitude. It is assumed that the pressure pulse accounts for the biomedical effects of the device. The slower inertial motion of the waveguide is damped by elastic stoppers, but still can be measured several micro seconds after the initial pressure pulse. In order to characterize the pressure pulse devices, field mapping is performed on several radial pressure pulse sources using the fiber optic hydrophone and a polyvinylidenfluorid (PVDF piezoelectric hydrophone. It could be shown that the current standard (IEC 61846 is not appropriate for characterization of ballistic pressure pulse sources.

  3. FR II radio galaxies at low frequencies - II. Spectral ageing and source dynamics

    Science.gov (United States)

    Harwood, Jeremy J.; Hardcastle, Martin J.; Morganti, Raffaella; Croston, Judith H.; Brüggen, Marcus; Brunetti, Gianfranco; Röttgering, Huub J. A.; Shulevski, Aleksander; White, Glenn J.

    2017-07-01

    In this paper, the second in a series investigating Fanaroff-Riley type II (FR II) radio galaxies at low frequencies, we use LOw Frequency ARray (LOFAR) and Very Large Array (VLA) observations between 117 and 456 MHz, in addition to archival data, to determine the dynamics and energetics of two radio galaxies, 3C 452 and 3C 223, by fitting spectral ageing models on small spatial scales. We provide improved measurements for the physical extent of the two sources, including a previously unknown low surface brightness extension to the northern lobe of 3C 223, and revised energetics based on these values. We find spectral ages of 77.05^{+9.22}_{-8.74} and 84.96^{+15.02}_{-13.83} Myr for 3C 452 and 3C 223, respectively, suggesting a characteristic advance speed for the lobes of around 1 per cent of the speed of light. For 3C 452, we show that, even for a magnetic field strength not assumed to be in equipartition, a disparity of a factor of approximately 2 exists between the spectral age and that determined from a dynamical standpoint. We confirm that the injection index of both sources (as derived from the lobe emission) remains steeper than classically assumed values, even when considered on well-resolved scales at low frequencies. However, we find an unexpected sharp discontinuity between the spectrum of the hotspots and the surrounding lobe emission. We suggest that this discrepancy is a result of the absorption of hotspot emission and/or non-homogeneous and additional acceleration mechanisms; as such, hotspots should not be used in the determination of the underlying initial electron energy distribution.

  4. Testing of a one dimensional model for Field II calibration

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2008-01-01

    to the calibrated Field II program for 1, 4, and 10 cycle excitations. Two parameter sets were applied for modeling, one real valued Pz27 parameter set, manufacturer supplied, and one complex valued parameter set found in literature, Alguer´o et al. [11]. The latter implicitly accounts for attenuation. Results show......Field II is a program for simulating ultrasound transducer fields. It is capable of calculating the emitted and pulse-echoed fields for both pulsed and continuous wave transducers. To make it fully calibrated a model of the transducer’s electro-mechanical impulse response must be included. We...... examine an adapted one dimensional transducer model originally proposed by Willatzen [9] to calibrate Field II. This model is modified to calculate the required impulse responses needed by Field II for a calibrated field pressure and external circuit current calculation. The testing has been performed...

  5. The Theory of Quantized Fields. II

    Science.gov (United States)

    Schwinger, J.

    1951-01-01

    The arguments leading to the formulation of the Action Principle for a general field are presented. In association with the complete reduction of all numerical matrices into symmetrical and anti-symmetrical parts, the general field is decomposed into two sets, which are identified with Bose-Einstein and Fermi-Dirac fields. The spin restriction on the two kinds of fields is inferred from the time reflection invariance requirement. The consistency of the theory is verified in terms of a criterion involving the various generators of infinitesimal transformations. Following a discussion of charged fields, the electromagnetic field is introduced to satisfy the postulate of general gauge invariance. As an aspect of the latter, it is recognized that the electromagnetic field and charged fields are not kinematically independent. After a discussion of the field-strength commutation relations, the independent dynamical variable of the electromagnetic field are exhibited in terms of a special gauge.

  6. Sound power radiated by sources in diffuse fields

    DEFF Research Database (Denmark)

    Polack, Jean-Dominique

    2000-01-01

    Sound power radiated by sources at low frequency notoriously depends on source position. We sampled the sound field of a rectangular room at 18 microphone and 4 source positions. Average power spectra were extrapolated from the reverberant field, taking into account the frequency dependent...... reverberation times. They reveal fluctuations that depend on source position and extend far above Schroeder frequency....

  7. Cropscout II, a modular mini field robot for precision agriculture

    NARCIS (Netherlands)

    Hemming, J.; Tuijl, van B.A.J.; Balendonck, J.; Henten, van E.J.; Janssen, H.J.J.

    2009-01-01

    In this paper a small agricultural robot named Cropscout II is described. Besides the objective to participate in the annual Field Robot Event competition Cropscout II operates as a modular test bed for autonomous robot control using sensor fusion techniques and artificial intelligence. The main cha

  8. Plasma wake field XUV radiation source

    Energy Technology Data Exchange (ETDEWEB)

    Prono, Daniel S. (Los Alamos, NM); Jones, Michael E. (Los Alamos, NM)

    1997-01-01

    A XUV radiation source uses an interaction of electron beam pulses with a gas to create a plasma radiator. A flowing gas system (10) defines a circulation loop (12) with a device (14), such as a high pressure pump or the like, for circulating the gas. A nozzle or jet (16) produces a sonic atmospheric pressure flow and increases the density of the gas for interacting with an electron beam. An electron beam is formed by a conventional radio frequency (rf) accelerator (26) and electron pulses are conventionally formed by a beam buncher (28). The rf energy is thus converted to electron beam energy, the beam energy is used to create and then thermalize an atmospheric density flowing gas to a fully ionized plasma by interaction of beam pulses with the plasma wake field, and the energetic plasma then loses energy by line radiation at XUV wavelengths Collection and focusing optics (18) are used to collect XUV radiation emitted as line radiation when the high energy density plasma loses energy that was transferred from the electron beam pulses to the plasma.

  9. Impedance-Source Networks for Electric Power Conversion Part II

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Peng, Fang Zheng; Blaabjerg, Frede

    2015-01-01

    Impedance-source networks cover the entire spectrum of electric power conversion applications (dc-dc, dc-ac, ac-dc, ac-ac) controlled and modulated by different modulation strategies to generate the desired dc or ac voltage and current at the output. A comprehensive review of various impedance-source......-network-based power converters has been covered in a previous paper and main topologies were discussed from an application point of view. Now Part II provides a comprehensive review of the most popular control and modulation strategies for impedance-source network-based power converters/inverters. These methods...... topology at a certain power level, switching frequency and demanded dynamic response....

  10. Concepts of UCN sources for the FRM-II

    CERN Document Server

    Trinks, U; Paul, S; Schott, W

    2000-01-01

    Three concepts for sources of ultra-cold neutrons (UCN) for the reactor FRM-II at Garching near Munich are studied: one, Mini-D sub 2 , is a source with 170 cm sup 3 of solid deuterium in the beam tube SR4 and the second one a large solid-deuterium source (volume about 30 dm sup 3), mounted in the beam tube SR5 as an advanced cold source with a number of neutron guides. The third one, Mark 3000, uses superfluid sup 4 He at a cold-neutron guide. A UCN density of up to 7x10 sup 4 cm sup - sup 3 may possibly be achieved in the storage volumes of Mini-D sub 2 yielding more than 10 sup 9 UCN for extraction to an attached experimental setup. The usable UCN flux at the periphery of the large deuterium source is predicted to be 2x10 sup 7 cm sup - sup 2 s sup - sup 1. Mark 3000, finally, is expected to yield a UCN density of about 10 sup 5 cm sup - sup 3.

  11. Acoustic source localization in mixed field using spherical microphone arrays

    Science.gov (United States)

    Huang, Qinghua; Wang, Tong

    2014-12-01

    Spherical microphone arrays have been used for source localization in three-dimensional space recently. In this paper, a two-stage algorithm is developed to localize mixed far-field and near-field acoustic sources in free-field environment. In the first stage, an array signal model is constructed in the spherical harmonics domain. The recurrent relation of spherical harmonics is independent of far-field and near-field mode strengths. Therefore, it is used to develop spherical estimating signal parameter via rotational invariance technique (ESPRIT)-like approach to estimate directions of arrival (DOAs) for both far-field and near-field sources. In the second stage, based on the estimated DOAs, simple one-dimensional MUSIC spectrum is exploited to distinguish far-field and near-field sources and estimate the ranges of near-field sources. The proposed algorithm can avoid multidimensional search and parameter pairing. Simulation results demonstrate the good performance for localizing far-field sources, or near-field ones, or mixed field sources.

  12. Coronal magnetic fields from multiple type II bursts

    Science.gov (United States)

    Honnappa, Vijayakumar; Raveesha, K. H.; Subramanian, K. R.

    Coronal magnetic fields from multiple type II bursts Vijayakumar H Doddamani1*, Raveesha K H2 and Subramanian3 1Bangalore University, Bangalore, Karnataka state, India 2CMR Institute of Technology, Bangalore, Karnataka state, India 3 Retd, Indian Institute of Astrophysics, Bangalore, Karnataka state, India Abstract Magnetic fields play an important role in the astrophysical processes occurring in solar corona. In the solar atmosphere, magnetic field interacts with the plasma, producing abundant eruptive activities. They are considered to be the main factors for coronal heating, particle acceleration and the formation of structures like prominences, flares and Coronal Mass Ejections. The magnetic field in solar atmosphere in the range of 1.1-3 Rsun is especially important as an interface between the photospheric magnetic field and the solar wind. Its structure and time dependent change affects space weather by modifying solar wind conditions, Cho (2000). Type II doublet bursts can be used for the estimation of the strength of the magnetic field at two different heights. Two type II bursts occur sometimes in sequence. By relating the speed of the type II radio burst to Alfven Mach Number, the Alfven speed of the shock wave generating type II radio burst can be calculated. Using the relation between the Alfven speed and the mean frequency of emission, the magnetic field strength can be determined at a particular height. We have used the relative bandwidth and drift rate properties of multiple type II radio bursts to derive magnetic field strengths at two different heights and also the gradient of the magnetic field in the outer corona. The magnetic field strength has been derived for different density factors. It varied from 1.2 to 2.5 gauss at a solar height of 1.4 Rsun. The empirical relation of the variation of the magnetic field with height is found to be of the form B(R) = In the present case the power law index ‘γ’ varied from -3 to -2 for variation of

  13. Simulating Capacitive Micromachined Ultrasonic Transducers (CMUTs) using Field II

    DEFF Research Database (Denmark)

    Bæk, David; Oralkan, Omer; Kupnik, Mario;

    2010-01-01

    Field II has been a recognized simulation tool for piezoceramic medical transducer arrays for more than a decade. The program has its strength in doing fast computations of the spatial impulse response (SIR) from array elements by dividing the elements into smaller mathematical elements (ME)s from...... which it calculates the SIR responses. The program features predefined models for classical transducer geometries, but currently none for the fast advancing CMUTs. This work addresses the assumptions required for modeling CMUTs with Field II. It is shown that rectangular array elements, populated...

  14. On the Relationship of UC H II Regions and Class II Methanol Masers: I. Source Catalogs

    CERN Document Server

    Hu, Bo; Wu, Yuanwei; Bartkiewicz, Anna; Rygl, Kazi; Reid, Mark J; Urquhart, James S; Zheng, Xingwu

    2016-01-01

    We conducted VLA C-configuration observations to measure positions and luminosities of Galactic Class II 6.7 GHz methanol masers and their associated ultra-compact H II regions. The spectral resolution was 3.90625 kHz and the continuum sensitivity reached 45 \\uJypb. We mapped 372 methanol masers with peak flux densities of more than 2 Jy selected from the literature, 367 of them were detected. Absolute positions have nominal uncertainties of 0.3 arcsec. In this first paper on the data analysis, we present three catalogs, the first gives information on the strongest feature of 367 methanol maser sources, and the second on all detected maser spots. The third catalog present derived data of the 279 radio continuum sources found in the vicinity of maser sources. Among them, 140 show evidence of physical association with maser sources. Our catalogs list properties including distance, flux density, radial velocity and the distribution of masers on the Galactic plane is then provided as well. We found no significant...

  15. Design of Magnetic Field System for Calutron Ion Source Set

    Institute of Scientific and Technical Information of China (English)

    REN; Xiu-yan; ZENG; Zi-qiang

    2013-01-01

    The Calutron ion source is the most important equipment of EMIS,and the structure of the ion source is more complicated.Because the parameter of each part is interrelate,as experiment and test set,It is very convenient to adjust the parameter of ion source and make the ion source get a good quality.Magnetic field system is the leading and necessary auxiliary equipment of the Calutron ion source

  16. Field biomass as global energy source

    Directory of Open Access Journals (Sweden)

    K. HAKALA

    2008-12-01

    Full Text Available Current (1997–2006 and future (2050 global field biomass bioenergy potential was estimated based on FAO (2009 production statistics and estimations of climate change impacts on agriculture according to emission scenario B1 of IPCC. The annual energy potential of raw biomass obtained from crop residues and bioenergy crops cultivated in fields set aside from food production is at present 122–133 EJ, 86–93 EJ or 47–50 EJ, when a vegetarian, moderate or affluent diet is followed, respectively. In 2050, with changes in climate and increases in population, field bioenergy production potential could be 101–110 EJ, 57–61 EJ and 44–47 EJ, following equivalent diets. Of the potential field bioenergy production, 39–42 EJ now and 38–41 EJ in 2050 would derive from crop residues. The residue potential depends, however, on local climate, and may be considerably lower than the technically harvestable potential, when soil quality and sustainable development are considered. Arable land could be used for bioenergy crops, particularly in Australia, South and Central America and the USA. If crop production technology was improved in areas where environmental conditions allow more efficient food production, such as the former Soviet Union, large areas in Europe could also produce bioenergy in set aside fields. The realistic potential and sustainability of field bioenergy production are discussed.;

  17. Calibration of Field II using a Convex Ultrasound Transducer

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2010-01-01

    Field II is an ultrasound simulation program capable of simulating the pressure scattering from inhomogeneous tissue. The simulations are based on a convolution between spatial impulse responses from the field in front of the transducer and the volt-to-surface acceleration impulse response...... of the transducer. For such simulations to reflect actual measured intensities and pressure levels, the transducer impulse response is to be known. This work presents the results of combining a modified form of a 1D linear transducer model originally suggested by Willatzen with the Field II program to calibrate...... BK-Medical (Herlev, Denmark). As input waveform for the Field model we measured the output voltage of the research amplifier, which peak voltage was limited to 31 V to avoid too high non linear effects. We measured the hydrophone output from three transducer front elements by averaging 40 shoot...

  18. Multilayer piezoelectric transducer models combined with Field II

    DEFF Research Database (Denmark)

    Bæk, David; Willatzen, Morten; Jensen, Jørgen Arendt

    2012-01-01

    with a polymer ring, and submerged into water. The transducer models are developed to account for any external electrical loading impedance in the driving circuit. The models are adapted to calculate the surface acceleration needed by the Field II software in predicting pressure pulses at any location in front...

  19. Linac Coherent Light Source II (LCLS-II) Conceptual Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Stohr, J

    2011-11-16

    The LCLS-II Project is designed to support the DOE Office of Science mission, as described in the 22 April 2010 Mission Need Statement. The scope of the Project was chosen to provide an increase in capabilities and capacity for the facility both at project completion in 2017 and in the subsequent decade. The Project is designed to address all points of the Mission Need Statement (MNS): (1) Expanded spectral reach; (2) Capability to provide x-ray beams with controllable polarization; (3) Capability to provide 'pump' pulses over a vastly extended range of photon energies to a sample, synchronized to LCLS-II x-ray probe pulses with controllable inter-pulse time delay; and (4) Increase of user access through parallel rather than serial x-ray beam use within the constraint of a $300M-$400M Total Project Cost (TPC) range. The LCLS-II Project will construct: (1) A hard x-ray undulator source (2-13 keV); (2) A soft x-ray undulator source (250-2,000 eV); (3) A dedicated, independent electron source for these new undulators, using sectors 10-20 of the SLAC linac; (4) Modifications to existing SLAC facilities for the injector and new shielded enclosures for the undulator sources, beam dumps and x-ray front ends; (5) A new experiment hall capable of accommodating four experiment stations; and (6) Relocation of the two soft x-ray instruments in the existing Near Experiment Hall (NEH) to the new experiment hall (Experiment Hall-II). A key objective of LCLS-II is to maintain near-term international leadership in the study of matter on the fundamental atomic length scale and the associated ultrafast time scales of atomic motion and electronic transformation. Clearly, such studies promise scientific breakthroughs in key areas of societal needs like energy, environment, health and technology, and they are uniquely enabled by forefront X-ray Free Electron Laser (X-FEL) facilities. While the implementation of LCLS-II extends to about 2017, it is important to realize that

  20. A microsystems enabled field desorption source.

    Energy Technology Data Exchange (ETDEWEB)

    Hertz, Kristin L.; Resnick, Paul James; Schwoebel, Paul R. (University of New Mexico, Albuquerque, NM); Holland, Christopher E. (SRI International, Menlo Park, CA); Chichester, David L. (Idaho National Laboratory, Idaho Falls, ID)

    2010-07-01

    Technologies that have been developed for microelectromechanical systems (MEMS) have been applied to the fabrication of field desorption arrays. These techniques include the use of thick films for enhanced dielectric stand-off, as well as an integrated gate electrode. The increased complexity of MEMS fabrication provides enhanced design flexibility over traditional methods.

  1. Agreements concluded by the Federal Republic of Germany under international law in the field of environmental protection. Source index in the Federal Law Gazette, part II. As of June 1, 1992. Voelkerrechtliche Vereinbarungen der Bundesrepublik Deutschland auf dem Gebiet des Umweltschutzes. Fundstellen im Bundesgesetzblatt II. Stand 1. Juni 1992

    Energy Technology Data Exchange (ETDEWEB)

    Lohse, S. (comp.)

    1992-06-01

    This compilation contains all agreements under international law in the field of environmental protection, the FRG has joined and that have been published and/or announced in the Federal Law Gazette, part II. The summary is of September 15, 1987. The classification is made according to the subjects: waste management law, pollution is made according to the date of treaty/agreement. For easier access, there are a chronological index, an index of the contracting states and an index of the places of contract. In the annex the relevant treaties with the German Democratic Republic are indicated. (orig.)

  2. Instability in the magnetic field penetration in type II superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Isaías G. de, E-mail: isaias@ufrrj.br

    2015-07-17

    Under the view of the time-dependent Ginzburg–Landau theory we have investigated the penetration of the magnetic field in the type II superconductors. We show that the single vortices, situated along the borderline, between the normal region channel and the superconducting region, can escape to regions still empty of vortices. We show that the origin of this process is the repulsive nature of vortex–vortex interaction, in addition to the non-homogeneous distribution of the vortices along the normal region channel. Using London theory we explain the extra gain of kinetic energy by the vortices situated along this borderline. - Highlights: • TDGL is used to study the magnetic field penetration in type II superconductors. • Instability process is found during the magnetic field penetration. • Vortices along the front of the normal region escape to superconducting region. • We explain the extra-gain of kinetic energy by vortices along the borderline.

  3. Personal Exposure to Contaminant Sources in a Uniform Velocity Field

    DEFF Research Database (Denmark)

    Brohus, Henrik; Nielsen, Peter V.

    The objective of this study has been to determine the personal exposure to a contaminant source in a uniform velocity field. This was done by full-scale measurements and computer simulations. The results showed a significant dependence on the velocity field both regarding the direction and the ma...... the usual operation range. Guidelines for personal exposure reduction in a uniform velocity field are discussed.......The objective of this study has been to determine the personal exposure to a contaminant source in a uniform velocity field. This was done by full-scale measurements and computer simulations. The results showed a significant dependence on the velocity field both regarding the direction...

  4. Refurbishment of a used in-vacuum undulator from the National Synchrotron Light Source for the National Synchrotron Light Source-II ring.

    Science.gov (United States)

    Tanabe, Toshiya; Bassan, Harmanpreet; Broadbent, Andrew; Cappadoro, Peter; Escallier, John; Harder, David; Hetzel, Charles; Hidas, Dean; Kitegi, Charles; Kosciuk, Bernard; Musardo, Marco; Kirkland, Johnny

    2017-09-01

    The National Synchrotron Light Source (NSLS) ceased operation in September 2014 and was succeeded by NSLS-II. There were four in-vacuum undulators (IVUs) in operation at NSLS. The most recently constructed IVU for NSLS was the mini-gap undulator (MGU-X25, to be renamed IVU18 for NSLS-II), which was constructed in 2006. This device was selected to be reused for the New York Structural Biology Consortium Microdiffraction beamline at NSLS-II. At the time of construction, IVU18 was a state-of-the-art undulator designed to be operated as a cryogenic permanent-magnet undulator. Due to the more stringent field quality and impedance requirements of the NSLS-II ring, the transition region was redesigned. The control system was also updated to NSLS-II specifications. This paper reports the details of the IVU18 refurbishment activities including additional magnetic measurement and tuning.

  5. Herschel-ATLAS: Planck sources in the Phase 1 fields

    CERN Document Server

    Herranz, D; Clements, D L; Clemens, M; De Zotti, G; López-Caniego, M; Lapi, A; Rodighiero, G; Danese, L; Fu, H; Cooray, A; Baes, M; Bendo, G J; Bonavera, L; Carrera, F J; Dole, H; Eales, S; Ivison, R J; Jarvis, M; Lagache, G; Massardi, M; Michalowski, M J; Negrello, M; Rigby, E; Scott, D; Valiante, E; Valtchanov, I; Van der Werf, P; Auld, R; Buttiglione, S; Dariush, A; Dunne, L; Hopwood, R; Hoyos, C; Ibar, E; Maddox, S

    2012-01-01

    We present the results of a cross-correlation of the Planck Early Release Compact Source Catalog (ERCSC) with the catalog of Herschel-ATLAS sources detected in the Phase 1 fields, covering 134.55 deg2. There are 28 ERCSC sources detected by Planck at 857 GHz in this area. As many as 16 of them are probably high Galactic latitude cirrus; 10 additional sources can be clearly identified as bright, low-z galaxies; one further source is resolved by Herschel as two relatively bright sources; and the last is resolved into an unusual condensation of low-flux, probably high-redshift point sources, around a strongly lensed Herschel-ATLAS source at z = 3.26. Our results demonstrate that the higher sensitivity and higher angular resolution H-ATLAS maps provide essential information for the interpretation of candidate sources extracted from Planck sub-mm maps.

  6. PM10 source measurement methodology: Field studies

    Energy Technology Data Exchange (ETDEWEB)

    Farthing, W.E.; Martin, R.S.; Dawes, S.S.; Williamson, A.D.

    1989-05-01

    Two candidate measurement methods, Constant Sampling Rate (CSR) and Exhaust Gas Recycle (EGR), have been developed to measure emissions of in-stack PM-10 particulate matter with aerodynamic diameter less than 10 micrometers. Two field tests were performed at the clinker cooler exhaust of a Portland cement plant to quantify precision and comparability of these techniques. In addition, accuracy was determined for total particulate measurement by comparison to Method 17. Collocated sampling trains were operated parallel with two Method 17 trains. In the second test, two CSR and one EGR trains were operated parallel to two Method 17 trains. The operating procedures used for the CSR and EGR trains are described in detail. In measurement of PM-10 and total particulate matter, the precision of both the CSR and EGR techniques was found to be of the same magnitude as Method 17 (approximately 5%). A small bias was found between CSR and EGR PM-10 results (15%) and between EGR and Method 17 total particulate matter (10%). Although small, these observed differences, combined with the results of laboratory studies reported elsewhere, led to a recommendation for an increase in the length of sampling nozzles. This modification improved cyclone performance and is incorporated into the nozzle geometries described in the application guides for CSR and EGR.

  7. Quantum correlations in nuclear mean field theory through source terms

    CERN Document Server

    Lee, S J

    1996-01-01

    Starting from full quantum field theory, various mean field approaches are derived systematically. With a full consideration of external source dependence, the stationary phase approximation of an action gives a nuclear mean field theory which includes quantum correlation effects (such as particle-hole or ladder diagram) in a simpler way than the Brueckner-Hartree-Fock approach. Implementing further approximation, the result can be reduced to Hartree-Fock or Hartree approximation. The role of the source dependence in a mean field theory is examined.

  8. Concerning the work of the II international field archaeological school

    Directory of Open Access Journals (Sweden)

    Sitdikov Ayrat G.

    2015-09-01

    Full Text Available The II international field archaeological school was held in Bolgar, 17-30 August, 2015. Basic theoretical lectures were included into syllabus, as well as methodical studies and work of such scientific sections as: History of ancient metallurgy and metal processing; Palaeoanthropology; Archeobiological methods in archaeology; Techniques of field conservation and restoration; Geoinformational systems in archaeology; History of ancient ceramics; Experimental and traseology study of ancient tools; Archaeological glass. The Bolgar school is an example of organisation an academic educational centre which is focused on practical acquisition of contemporary techniques of complex archaeological monuments’ study with wide usage of experimental research methods.

  9. Exotic dual of type II double field theory

    Science.gov (United States)

    Bergshoeff, Eric A.; Hohm, Olaf; Riccioni, Fabio

    2017-04-01

    We perform an exotic dualization of the Ramond-Ramond fields in type II double field theory, in which they are encoded in a Majorana-Weyl spinor of O (D , D). Starting from a first-order master action, the dual theory in terms of a tensor-spinor of O (D , D) is determined. This tensor-spinor is subject to an exotic version of the (self-)duality constraint needed for a democratic formulation. We show that in components, reducing O (D , D) to GL (D), one obtains the expected exotically dual theory in terms of mixed Young tableaux fields. To this end, we generalize exotic dualizations to self-dual fields, such as the 4-form in type IIB string theory.

  10. Exotic dual of type II double field theory

    Directory of Open Access Journals (Sweden)

    Eric A. Bergshoeff

    2017-04-01

    Full Text Available We perform an exotic dualization of the Ramond–Ramond fields in type II double field theory, in which they are encoded in a Majorana–Weyl spinor of O(D,D. Starting from a first-order master action, the dual theory in terms of a tensor–spinor of O(D,D is determined. This tensor–spinor is subject to an exotic version of the (self-duality constraint needed for a democratic formulation. We show that in components, reducing O(D,D to GL(D, one obtains the expected exotically dual theory in terms of mixed Young tableaux fields. To this end, we generalize exotic dualizations to self-dual fields, such as the 4-form in type IIB string theory.

  11. Reaching saturation in patterned source vertical organic field effect transistors

    Science.gov (United States)

    Greenman, Michael; Sheleg, Gil; Keum, Chang-min; Zucker, Jonathan; Lussem, Bjorn; Tessler, Nir

    2017-05-01

    Like most of the vertical transistors, the Patterned Source Vertical Organic Field Effect Transistor (PS-VOFET) does not exhibit saturation in the output characteristics. The importance of achieving a good saturation is demonstrated in a vertical organic light emitting transistor; however, this is critical for any application requiring the transistor to act as a current source. Thereafter, a 2D simulation tool was used to explain the physical mechanisms that prevent saturation as well as to suggest ways to overcome them. We found that by isolating the source facet from the drain-source electric field, the PS-VOFET architecture exhibits saturation. The process used for fabricating such saturation-enhancing structure is then described. The new device demonstrated close to an ideal saturation with only 1% change in the drain-source current over a 10 V change in the drain-source voltage.

  12. Excitation of field line resonances by sources outside the magnetosphere

    Directory of Open Access Journals (Sweden)

    A. D. M. Walker

    2005-11-01

    Full Text Available Field line resonances are thought to be excited by sources either at the magnetopause or outside it. Recent observations suggest that they may be associated with coherent oscillations or pressure pulses in the solar wind. In either case the excitation mechanism can be understood by considering the incidence of a harmonic wave on the magnetopause from outside the magnetosphere. Calculations are performed in a plane stratified model that consists of (i a magnetosheath region streaming tailward at uniform velocity (ii a sharp boundary representing the magnetopause, (iii a magnetosphere region in which the Alfvén speed increases monotonically with distance from the magnetopause. The structure implies the existence of a propagating region within the magnetopause bounded by a reflection level or turning point. Beyond this is a region in which waves are evanescent and a resonance level. The reflection and transmission of harmonic waves incident from the magnetosheath is considered in this model. It is shown that, in most cases, because of the mismatch between the magnetosphere and the magnetopause, the wave is reflected from the magnetopause with little penetration. At critical frequencies corresponding to the natural frequencies of the cavity formed between the magnetopause and turning point the signal excites the cavity and may leak evanescently to the resonance. The calculation includes the effect of the counter-streaming magnetosheath and magnetosphere plasmas on the wave. This can lead to amplification or attenuation. The nature of the processes that lead to transmission of the wave from magnetosheath to resonance are considered by synthesising the signal from plane wave spectra. A number of mechanisms for exciting cavity modes are reviewed and the relationship of the calculations to these mechanisms are discussed. Observations needed to discriminate between the mechanisms are specified.

  13. Transverse Field Perturbation For PIP-II SRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Berrutti, Paolo [Fermilab; Khabiboulline, Timergali N. [Fermilab; Lebedev, Valeri [Fermilab; Yakovlev, Vyacheslav P. [Fermilab

    2015-06-01

    Proton Improvement Plan II (PIP-II) consists in a plan for upgrading the Fermilab proton accelerator complex to a beam power capability of at least 1 MW delivered to the neutrino production target. A room temperature section accelerates H⁻ ions to 2.1 MeV and creates the desired bunch structure for injection into the superconducting (SC) linac. Five cavity types, operating at three different frequencies 162.5, 325 and 650 MHz, provide acceleration to 800 MeV. This paper presents the studies on transverse field perturbation on particle dynamic for all the superconducting cavities in the linac. The effects studied include quadrupole defocusing for coaxial resonators, and dipole kick due to couplers for elliptical cavities. A multipole expansion has been performed for each of the cavity designs including effects up to octupole.

  14. FR II radio galaxies at low frequencies - I. Morphology, magnetic field strength and energetics

    Science.gov (United States)

    Harwood, Jeremy J.; Croston, Judith H.; Intema, Huib T.; Stewart, Adam J.; Ineson, Judith; Hardcastle, Martin J.; Godfrey, Leith; Best, Philip; Brienza, Marisa; Heesen, Volker; Mahony, Elizabeth K.; Morganti, Raffaella; Murgia, Matteo; Orrú, Emanuela; Röttgering, Huub; Shulevski, Aleksandar; Wise, Michael W.

    2016-06-01

    Due to their steep spectra, low-frequency observations of Fanaroff-Riley type II (FR II) radio galaxies potentially provide key insights in to the morphology, energetics and spectrum of these powerful radio sources. However, limitations imposed by the previous generation of radio interferometers at metre wavelengths have meant that this region of parameter space remains largely unexplored. In this paper, the first in a series examining FR IIs at low frequencies, we use LOFAR (LOw Frequency ARray) observations between 50 and 160 MHz, along with complementary archival radio and X-ray data, to explore the properties of two FR II sources, 3C 452 and 3C 223. We find that the morphology of 3C 452 is that of a standard FR II rather than of a double-double radio galaxy as had previously been suggested, with no remnant emission being observed beyond the active lobes. We find that the low-frequency integrated spectra of both sources are much steeper than expected based on traditional assumptions and, using synchrotron/inverse-Compton model fitting, show that the total energy content of the lobes is greater than previous estimates by a factor of around 5 for 3C 452 and 2 for 3C 223. We go on to discuss possible causes of these steeper-than-expected spectra and provide revised estimates of the internal pressures and magnetic field strengths for the intrinsically steep case. We find that the ratio between the equipartition magnetic field strengths and those derived through synchrotron/inverse-Compton model fitting remains consistent with previous findings and show that the observed departure from equipartition may in some cases provide a solution to the spectral versus dynamical age disparity.

  15. FR II radio galaxies at low frequencies - I. Morphology, magnetic field strength and energetics.

    Science.gov (United States)

    Harwood, Jeremy J; Croston, Judith H; Intema, Huib T; Stewart, Adam J; Ineson, Judith; Hardcastle, Martin J; Godfrey, Leith; Best, Philip; Brienza, Marisa; Heesen, Volker; Mahony, Elizabeth K; Morganti, Raffaella; Murgia, Matteo; Orrú, Emanuela; Röttgering, Huub; Shulevski, Aleksandar; Wise, Michael W

    2016-06-01

    Due to their steep spectra, low-frequency observations of Fanaroff-Riley type II (FR II) radio galaxies potentially provide key insights in to the morphology, energetics and spectrum of these powerful radio sources. However, limitations imposed by the previous generation of radio interferometers at metre wavelengths have meant that this region of parameter space remains largely unexplored. In this paper, the first in a series examining FR IIs at low frequencies, we use LOFAR (LOw Frequency ARray) observations between 50 and 160 MHz, along with complementary archival radio and X-ray data, to explore the properties of two FR II sources, 3C 452 and 3C 223. We find that the morphology of 3C 452 is that of a standard FR II rather than of a double-double radio galaxy as had previously been suggested, with no remnant emission being observed beyond the active lobes. We find that the low-frequency integrated spectra of both sources are much steeper than expected based on traditional assumptions and, using synchrotron/inverse-Compton model fitting, show that the total energy content of the lobes is greater than previous estimates by a factor of around 5 for 3C 452 and 2 for 3C 223. We go on to discuss possible causes of these steeper-than-expected spectra and provide revised estimates of the internal pressures and magnetic field strengths for the intrinsically steep case. We find that the ratio between the equipartition magnetic field strengths and those derived through synchrotron/inverse-Compton model fitting remains consistent with previous findings and show that the observed departure from equipartition may in some cases provide a solution to the spectral versus dynamical age disparity.

  16. Chandra X-Ray Sources in the LALA Cetus Field

    Science.gov (United States)

    Wang, J. X.; Zheng, Z. Y.; Malhotra, S.; Finkelstein, S. L.; Rhoads, J. E.; Norman, C. A.; Heckman, T. M.

    2007-11-01

    The 174 ks Chandra Advanced CCD Imaging Spectrometer exposure of the Large Area Lyman Alpha Survey (LALA) Cetus field is the second of the two deep Chandra images on LALA fields. In this paper we present the Chandra X-ray sources detected in the Cetus field, along with an analysis of X-ray source counts, stacked X-ray spectrum, and optical identifications. A total of 188 X-ray sources were detected: 174 in the 0.5-7.0 keV band, 154 in the 0.5-2.0 keV band, and 113 in the 2.0-7.0 keV band. The X-ray source counts were derived and compared with LALA field (172 ks exposure). Interestingly, we find consistent hard-band X-ray source density, but (36+/-12)% higher soft-band X-ray source density in Cetus field. The weighted stacked spectrum of the detected X-ray sources can be fitted by a power law with photon index Γ=1.55. Based on the weighted stacked spectrum, we find that the resolved fraction of the X-ray background drops from (72+/-1)% at 0.5-1.0 keV to (63+/-4)% at 6.0-8.0 keV. The unresolved spectrum can be fitted by a power law over the range 0.5-7 keV, with a photon index Γ=1.22. We also present optical counterparts for 154 of the X-ray sources, down to a limiting magnitude of r'=25.9 (Vega), using a deep r'-band image obtained with the MMT. Optical Observations reported here were obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution.

  17. On the Field of a Stationary Charged Spherical Source

    Directory of Open Access Journals (Sweden)

    Stavroulakis N.

    2009-04-01

    Full Text Available The equations of gravitation related to the field of a spherical charged source imply the existence of an interdependence between gravitation and electricity [5]. The present paper deals with the joint action of gravitation and electricity in the case of a stationary charged spherical source. Let m and " be respectively the mass and the charge of the source, and let k be the gravitational constant. Then the equations of gravitation need specific discussion according as j " j m p k (source strongly charged. In any case the curvature radius of the sphere bounding the matter possesses a strictly positive greatest lower hound, so that the source is necessarily an extended object. Pointwise sources do not exist. In particular, charged black holes do not exist.

  18. Electromagnetic and transient shielding effectiveness for near-field sources

    Directory of Open Access Journals (Sweden)

    C. Möller

    2007-06-01

    Full Text Available The contribution deals with an investigation of the recently proposed definitions for the electromagnetic and transient shielding effectiveness (SE in the case of an electric-dipole near-field source. To this end, new factors are introduced which depend on the distance between the dipole source and the measurement point inside the shield and which are valid for perpendicularly (with respect to the distance vector polarized dipoles. Numerical results support and confirm the theoretical derivations.

  19. Integral field spectroscopy of a sample of nearby galaxies: II. Properties of the H ii regions

    CERN Document Server

    Sanchez, S F; Marino, R A; Iglesias-Paramo, J; Vilchez, J M; Kennicutt, R C; Diaz, A I; Mast, D; Monreal-Ibero, A; Garcia-Benito, R; Bland-Hawthorn, J; Perez, E; Delgado, R Gonzalez; Husemann, B; Lopez-Sanchez, A R; Fernandes, R Cid; Kehrig, C; Walcher, C J; de Paz, A Gil; Ellis, S

    2012-01-01

    In this work we analyze the spectroscopic properties of a large number of H ii regions, \\sim2600, located in 38 galaxies. The sample of galaxies has been assembled from the face-on spirals in the PINGS survey and a sample described in M\\'armol-Queralt\\'o (2011, henceforth Paper I). All the galaxies were observed using Integral Field Spectroscopy with a similar setup, covering their optical extension up to \\sim2.4 effective radii within a wavelength range from \\sim3700 to \\sim6900{\\AA}. We develop a new automatic procedure to detect H ii regions, based on the contrast of the H{\\alpha} intensity maps. Once detected, the procedure provides us with the integrated spectra of each individual segmented region. A well-tested automatic decoupling procedure has been applied to remove the underlying stellar population, deriving the main proper- ties of the strongest emission lines in the considered wavelength range (covering from [O ii] {\\lambda}3727 to [S ii] {\\lambda}6731). A final catalogue of the spectroscopic prope...

  20. Classical Electromagnetic Field Theory in the Presence of Magnetic Sources

    Institute of Scientific and Technical Information of China (English)

    LI Kang(李康); CHEN Wen-Jun(陈文俊); NAON Carlos M.

    2003-01-01

    Using two new well-defined four-dimensional potential vectors, we formulate the classical Maxwell field theory in a form which has manifest Lorentz covariance and SO(2) duality symmetry in the presence of magnetic sources.We set up a consistent Lagrangian for the theory. Then from the action principle we obtain both Maxwell's equation and the equation of motion of a dyon moving in the electromagnetic field.

  1. Classical electromagnetic field theory in the presence of magnetic sources

    CERN Document Server

    Chen, W J; Naón, C M; Chen, Wen-Jun; Li, Kang

    2001-01-01

    Using two new well defined 4-dimensional potential vectors, we formulate the classical Maxwell's field theory in a form which has manifest Lorentz covariance and SO(2) duality symmetry in the presence of magnetic sources. We set up a consistent Lagrangian for the theory. Then from the action principle we get both Maxwell's equation and the equation of motion of a dyon moving in the electro-magnetic field.

  2. Near-field acoustic holography analysis of modulated sound source

    Institute of Scientific and Technical Information of China (English)

    MAO Rongfu; ZHU Haichao; DU Xianghua; ZHU Haipeng

    2011-01-01

    When conventional near-field acoustic holography (NAH) technique is appliedto sound field induced by modulated signal, the modulating frequency can not be revealed by the reconstructed results. To solve the problem, a NAH analysis methodology for modulated sound source was proposed. Firstly, Hilbert transform was introduced to demodulate the signal, and then modulating component was reconstructed by NAH technique. Both numerical simulation and experiment results demonstrate that accurate reconstruction analysis can be obtained by the proposed method.

  3. Wormhole solutions sourced by fluids, II: three-fluid two-charged sources

    Energy Technology Data Exchange (ETDEWEB)

    Azreg-Aïnou, Mustapha, E-mail: azreg@baskent.edu.tr [Faculty of Engineering, Başkent University, Bağlıca Campus, 06810, Ankara (Turkey)

    2016-01-05

    Lack of a consistent metric for generating rotating wormholes motivates us to present a new one endowed with interesting physical and geometrical properties. When combined with the generalized method of superposition of fields, which consists in attaching a form of matter to each moving frame, it generates massive and charged (charge without charge) two-fluid-sourced, massive and two-charged three-fluid-sourced, rotating as well as new static wormholes which, otherwise, can hardly be derived by integration. If the lapse function of the static wormhole is bounded from above, no closed timelike curves occur in the rotating counterpart. For positive energy densities dying out faster than 1 / r, the angular velocity includes in its expansion a correction term, to the leading one that corresponds to ordinary stars, proportional to lnr/r{sup 4}. Such a term is not present in the corresponding expansion for the Kerr–Newman black hole. Based on this observation and our previous work, the dragging effects of falling neutral objects may constitute a substitute for other known techniques used for testing the nature of the rotating black hole candidates that are harbored in the center of galaxies. We discuss the possibility of generating (n+1)-fluid-sourced, n-charged, rotating as well as static wormholes.

  4. Wormhole solutions sourced by fluids, II: three-fluid two-charged sources

    Energy Technology Data Exchange (ETDEWEB)

    Azreg-Ainou, Mustapha [Baskent University, Faculty of Engineering, Ankara (Turkey)

    2016-01-15

    Lack of a consistent metric for generating rotating wormholes motivates us to present a new one endowed with interesting physical and geometrical properties. When combined with the generalized method of superposition of fields, which consists in attaching a form of matter to each moving frame, it generates massive and charged (charge without charge) two-fluid-sourced, massive and two-charged three-fluid-sourced, rotating as well as new static wormholes which, otherwise, can hardly be derived by integration. If the lapse function of the static wormhole is bounded from above, no closed timelike curves occur in the rotating counterpart. For positive energy densities dying out faster than 1/r, the angular velocity includes in its expansion a correction term, to the leading one that corresponds to ordinary stars, proportional to ln r/r{sup 4}. Such a term is not present in the corresponding expansion for the Kerr-Newman black hole. Based on this observation and our previous work, the dragging effects of falling neutral objects may constitute a substitute for other known techniques used for testing the nature of the rotating black hole candidates that are harbored in the center of galaxies. We discuss the possibility of generating (n + 1)-fluid-sourced, n-charged, rotating as well as static wormholes. (orig.)

  5. First field experiences with OBD II; Erste Felderfahrungen mit OBD II

    Energy Technology Data Exchange (ETDEWEB)

    Zander, W. [AUDI AG, Ingolstadt (Germany)

    1994-12-31

    A report is given on first field experiences of the diagnosis technology (OBD II) with the help of examples. Since the vehicles which were sold to customers have not done enough miles yet the experience report mainly refers to AUDI`s own vehicles. The results are positive. Hence the company AUDI AG can claim that a sensitive, reliable system for assessing important engine components is available due to this new technology. (orig.) [Deutsch] Es wird anhand von Beispielen aus der Diagnosetechnik (OBD II) ueber erste Felderfahrungen berichtet. Da ausgelieferte Fahrzeuge beim Kunden noch zu geringe Laufstrecken hinter sich haben, beziehen sich die Erfahrungen in erster Linie auf eigene Dauerlaeufer. Die Ergebnisse sind positiv, so dass wir behaupten koennen, mit dieser Technik ein sensibles, zuverlaessiges System zur Beurteilung wesentlicher Motorkomponenten zur Verfuegung zu haben. (orig.)

  6. Top-up operation at Pohang Light Source-II

    Science.gov (United States)

    Hwang, I.; Huang, J. Y.; Kim, M.; Lee, B.-J.; Kim, C.; Choi, J.-Y.; Kim, M.-H.; Lee, H. S.; Moon, D.; Lee, E. H.; Kim, D.-E.; Nam, S. H.; Shin, S.; Cho, Moohyun

    2014-05-01

    After three years of upgrading work, PLS-II (S. Shin, Commissioning of the PLS-II, JINST, January 2013) is now successfully operating. The top-up operation of the 3 GeV linear accelerator had to be delayed because of some challenges encountered, and PLS-II was run in decay mode at the beginning in March 2012. The main difficulties encountered in the top-up operation of PLS-II are different levels between the linear accelerator and the storage ring, the 14 narrow gap in-vacuum undulators in operation, and the full energy injection by 3 GeV linear accelerator. Large vertical emittance and energy jitter of the linac were the major obstacles that called for careful control of injected beam to reduce beam loss in the storage ring during injection. The following measures were taken to resolve these problems: (1) The high resolution Libera BPM (see http://www.i-tech.si) was implemented to measure the beam trajectory and energy. (2) Three slit systems were installed to filter the beam edge. (3) De-Qing circuit was applied to the modulator system to improve the energy stability of injected beam. As a result, the radiation by beam loss during injection is reduced drastically, and the top-up mode has been successfully operating since 19th March 2013. In this paper, we describe the experimental results of the PLS-II top-up operation and the improvement plan.

  7. Further Sources of Our Field's Embattled Public Reputation

    Science.gov (United States)

    Lilienfeld, Scott O.

    2012-01-01

    Responds to the comments made by Newman et al., Tryon, and Teo on the current author's original article. In the original article on public skepticism toward psychology, the author delineated eight reasons why many laypersons are dubious of our field's scientific status. The author argued that although some of these sources (e.g., hindsight bias,…

  8. Thermal radiation field of low-temperature sources

    Science.gov (United States)

    Łakomy, T.

    1989-05-01

    The asymmetric thermal radiation field of heat sources existing in industry and in the building of apartments has been determined in this work. A description was realised by vector radiant and mean radiant temperatures ( VRT, TMR) obtaining their statistic reciprocal relationships at summer and winter terms.

  9. Locally covariant quantum field theory with external sources

    CERN Document Server

    Fewster, Christopher J

    2014-01-01

    We provide a detailed analysis of the classical and quantized theory of a multiplet of inhomogeneous Klein-Gordon fields, which couple to the spacetime metric and also to an external source term; thus the solutions form an affine space. Following the formulation of affine field theories in terms of presymplectic vector spaces as proposed in [Annales Henri Poincare 15, 171 (2014)], we determine the relative Cauchy evolution induced by metric as well as source term perturbations and compute the automorphism group of natural isomorphisms of the presymplectic vector space functor. Two pathological features of this formulation are revealed: the automorphism group contains elements that cannot be interpreted as global gauge transformations of the theory; moreover, the presymplectic formulation does not respect a natural requirement on composition of subsystems. We therefore propose a systematic strategy to improve the original description of affine field theories at the classical and quantized level, first passing ...

  10. Emission characteristics of AuSiBe field ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Drandarov, N.; Georgieva, St.; Nikolov, B.; Donchev, T. (Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. po Elektronika)

    A ribbon type AuSiBe alloy field ion source, which combines the advantages of both hairpin type sources and reservoir type sources, has been constructed. The current-voltage characteristics of this source have been investigated. Hysteresis and four differentiated emission regions have been observed for them. By means of scanning electronic microscopy, it has been established that this complicated behaviour of the I-V curves and the angular distribution of the extracted ions are associated with the shape of the emitting surface. The mass spectrum of the emitted ions has been determined by means of an E x B mass filter. Considerable emission of Au[sup +], AuBe[sub 3][sup 2+], Si[sup 2+], Be[sup 2+], AuBe[sub 3][sup +], Be[sup +], Si[sup +], and Au[sup 2+] has been observed. (author).

  11. Structure on Interplanetary Shock Fronts: Type II Radio Burst Source Regions

    CERN Document Server

    Pulupa, M

    2007-01-01

    We present \\emph{in situ} observations of the source regions of interplanetary (IP) type II radio bursts, using data from the Wind spacecraft during the period 1996-2002. We show the results of this survey as well as in-depth analysis of several individual events. Each event analyzed in detail is associated with an interplanetary coronal mass ejection (ICME) and an IP shock driven by the ICME. Immediately prior to the arrival of each shock, electron beams along the interplanetary magnetic field (IMF) and associated Langmuir waves are detected, implying magnetic connection to a quasiperpendicular shock front acceleration site. These observations are analogous to those made in the terrestrial foreshock region, indicating that a similar foreshock region exists on IP shock fronts. The analogy suggests that the electron acceleration process is a fast Fermi process, and this suggestion is borne out by loss cone features in the electron distribution functions. The presence of a foreshock region requires nonplanar st...

  12. A Survey of Fertilizer Dealers: II. Sources of Agronomic Information.

    Science.gov (United States)

    Schmitt, M. A.

    1988-01-01

    Reports on a survey of fertilizer dealers that was conducted to assess how the dealers were obtaining their agronomic information, aside from formal training sessions, and determine if these sources of information were satisfactory in fulfilling the dealers' needs. (TW)

  13. Discontinuous Electromagnetic Fields Using Huygens Sources For Wavefront Manipulation

    CERN Document Server

    Selvanayagam, Michael

    2013-01-01

    We introduce the idea of discontinuous electric and magnetic fields at a boundary to design and shape wavefronts in an arbitrary manner. To create this discontinuity in the field we use electric and magnetic currents which act like a Huygens source to radiate the desired wavefront. These currents can be synthesized either by an array of electric and magnetic dipoles or by a combined impedance and admittance surface. A dipole array is an active implementation to impose discontinuous fields while the impedance/admittance surface acts as a passive one. We then expand on our previous work showing how electric and magnetic dipole arrays can be used to cloak an object demonstrating two novel cloaking schemes. We also show how to arbitrarily refract a beam using a set of impedance and admittance surfaces. Refraction using the idea of discontinuous fields is shown to be a more general case of refraction using phase discontinuities.

  14. Cosmic Radiation Fields: Sources in the early Universe

    Science.gov (United States)

    Raue, Martin; Kneiske, Tanja; Horns, Dieter; Elsaesser, Dominik; Hauschildt, Peter

    The workshop "Cosmic Radiation Fields - Sources in the Early Universe" (CRF 2010) focuses on the connection between the extragalactic infrared background and sources in the early universe, in particular stars powered by dark matter burning (Dark Stars; DS). The workshop covers the following topics: the cosmic infrared background, formation of early stars, dark stars, effect of dark matter in the early universe, dark matter halos, primordial star formation rate, and reionization. Further information can be found on the conference webpage: http://www.desy.de/crf2010/. Organizing committee: Tanja Kneiske, Martin Raue, Dominik Elsaesser, Alexander Gewering-Peine, Peter Hausschildt, Dieter Horns, and Andreas Maurer.

  15. Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources

    Energy Technology Data Exchange (ETDEWEB)

    Geddes, Cameron G.R.; Cormier-Michel, Estelle; Esarey, Eric H.; Schroeder, Carl B.; Vay, Jean-Luc; Leemans, Wim P.; Bruhwiler, David L.; Cary, John R.; Cowan, Ben; Durant, Marc; Hamill, Paul; Messmer, Peter; Mullowney, Paul; Nieter, Chet; Paul, Kevin; Shasharina, Svetlana; Veitzer, Seth; Weber, Gunther; Rubel, Oliver; Ushizima, Daniela; Bethel, Wes; Wu, John

    2009-03-20

    Compared to conventional particle accelerators, plasmas can sustain accelerating fields that are thousands of times higher. To exploit this ability, massively parallel SciDAC particle simulations provide physical insight into the development of next-generation accelerators that use laser-driven plasma waves. These plasma-based accelerators offer a path to more compact, ultra-fast particle and radiation sources for probing the subatomic world, for studying new materials and new technologies, and for medical applications.

  16. Finding joy in social work. II: Intrapersonal sources.

    Science.gov (United States)

    Pooler, David Kenneth; Wolfer, Terry; Freeman, Miriam

    2014-07-01

    Despite the social work profession's strengths orientation, research on its workforce tends to focus on problems (for example, depression, problem drinking, compassion fatigue, burnout). In contrast, this study explored ways in which social workers find joy in their work. The authors used an appreciative inquiry approach, semistructured interviews (N = 26), and a collaborative grounded theory method of analysis. Participants identified interpersonal (making connections and making a difference) and intrapersonal (making meaning and making a life) sources of joy and reflected significant personal initiative in the process of finding joy. The authors present findings regarding these intrapersonal sources of joy.

  17. Geodesics in the field of a rotating deformed gravitational source

    CERN Document Server

    Boshkayev, Kuantay; Abutalip, Marzhan; Kalymova, Zhanerke; Suleymanova, Sharara

    2015-01-01

    We investigate equatorial geodesics in the gravitational field of a rotating and deformed source described by the approximate Hartle-Thorne metric. In the case of massive particles, we derive within the same approximation analytic expressions for the orbital angular velocity, the specific angular momentum and energy, and the radii of marginally stable and marginally bound circular orbits. Moreover, we calculate the orbital angular velocity and the radius of lightlike circular geodesics. We study numerically the frame dragging effect and the influence of the quadrupolar deformation of the source on the motion of test particles. We show that the effects originating from the rotation can be balanced by the effects due to the oblateness of the source.

  18. Geodesics in the field of a rotating deformed gravitational source

    Science.gov (United States)

    Boshkayev, K. A.; Quevedo, H.; Abutalip, M. S.; Kalymova, Zh. A.; Suleymanova, Sh. S.

    2016-01-01

    We investigate equatorial geodesics in the gravitational field of a rotating and deformed source described by the approximate Hartle-Thorne metric. In the case of massive particles, we derive within the same approximation analytic expressions for the orbital angular velocity, the specific angular momentum and energy, and the radii of marginally stable and marginally bound circular orbits. Moreover, we calculate the orbital angular velocity and the radius of lightlike circular geodesics. We study numerically the frame dragging effect and the influence of the quadrupolar deformation of the source on the motion of test particles. We show that the effects originating from the rotation can be balanced by the effects due to the oblateness of the source.

  19. Miniature field emission light sources for bio-chips

    Energy Technology Data Exchange (ETDEWEB)

    Cichy, Bartlomiej; Gorecka-Drzazga, Anna; Dziuban, Jan A [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wroclaw (Poland)], E-mail: bartlomiej.cichy@pwr.wroc.pl

    2009-01-01

    A concept based on preparation of miniature field emission light sources (FELS) for integration with bio-chips is presented. Glass and silicon-glass micro-fluidic systems (biochips) with spectrofluorometric detection are designated for this solution. Planar, miniature silicon-glass field emission light sources were designed and fabricated for this conception. Carbon nanotubes (CNTs) have been used as a low-voltage electron emissive layer. Nanocrystalline yttria matrices doped with rare earth (Re) ions (Re: Eu{sup 3+}, Tb{sup 3+}) have been synthesized and utilized as phosphor layers. Light emission spectral characteristics of fabricated sources allow to couple them with typical fluorescent markers as e.g. Alexa, Fluorescein or TO-PRO, used on the wide scale in biochemical researches. Fabricated FELSs are characterized by the intensive and homogenous light emission with well defined sharp emission lines. The efficient and stable field emission from carbon nanotubes has also been noticed. Fabricated FELS are technologically compatible with highly developing micromachined fluidic systems and are able to direct on-chip integration with these microsystems.

  20. 4D Near-Field Source Localization Using Cumulant

    Directory of Open Access Journals (Sweden)

    Zhao Feng

    2007-01-01

    Full Text Available This paper proposes a new cumulant-based algorithm to jointly estimate four-dimensional (4D source parameters of multiple near-field narrowband sources. Firstly, this approach proposes a new cross-array, and constructs five high-dimensional Toeplitz matrices using the fourth-order cumulants of some properly chosen sensor outputs; secondly, it forms a parallel factor (PARAFAC model in the cumulant domain using these matrices, and analyzes the unique low-rank decomposition of this model; thirdly, it jointly estimates the frequency, two-dimensional (2D directions-of-arrival (DOAs, and range of each near-field source from the matrices via the low-rank three-way array (TWA decomposition. In comparison with some available methods, the proposed algorithm, which efficiently makes use of the array aperture, can localize sources using sensors. In addition, it requires neither pairing parameters nor multidimensional search. Simulation results are presented to validate the performance of the proposed method.

  1. 4D Near-Field Source Localization Using Cumulant

    Directory of Open Access Journals (Sweden)

    Junying Zhang

    2007-01-01

    Full Text Available This paper proposes a new cumulant-based algorithm to jointly estimate four-dimensional (4D source parameters of multiple near-field narrowband sources. Firstly, this approach proposes a new cross-array, and constructs five high-dimensional Toeplitz matrices using the fourth-order cumulants of some properly chosen sensor outputs; secondly, it forms a parallel factor (PARAFAC model in the cumulant domain using these matrices, and analyzes the unique low-rank decomposition of this model; thirdly, it jointly estimates the frequency, two-dimensional (2D directions-of-arrival (DOAs, and range of each near-field source from the matrices via the low-rank three-way array (TWA decomposition. In comparison with some available methods, the proposed algorithm, which efficiently makes use of the array aperture, can localize N−3 sources using N sensors. In addition, it requires neither pairing parameters nor multidimensional search. Simulation results are presented to validate the performance of the proposed method.

  2. Gravitational Field of the Early Universe; 1, Non-linear Scalar Field as the Source

    CERN Document Server

    Chervon, S V

    1997-01-01

    In this review article we consider three most important sources of the gravitational field of the Early Universe: self-interacting scalar field, chiral field and gauge field. The correspondence between all of them are pointed out. More attention is payed to nonlinear scalar field source of gravity. The progress in finding the exact solutions in inflationary universe is reviewed. The basic idea of `fine turning of the potential' method is discussed and computational background is presented in details. A set of new exact solutions for standard inflationary model and conformally-flat space-times are obtained. Special attention payed to relations between `fine turning of the potential' and Barrow's approaches. As the example of a synthesis of both methods new exact solution is obtained.

  3. Analysis and categorization of information sources in the subject field of cynology

    OpenAIRE

    Bušková, Markéta

    2015-01-01

    The aim of this bachelor thesis, titled "Analysis and Categorization of Information Sources for the Field of Dog-breeding", is to map and analyze information sources relating to the field of dog-breeding, introduce dog-breeding as a field, compile an overview of current information sources for this field and focus on particularly defined groups of information sources.

  4. Hydrocyanation of sulfonylimines using potassium hexacyanoferrate(II) as an eco-friendly cyanide source

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zheng; Li, Rongzhi; Zheng, Huanhuan; Wen, Fei; Li, Hongbo; Yin, Junjun; Yang, Jingya, E-mail: lizheng@nwnu.edu.cn [Key Laboratory of Eco-Environment-Related Polymer Materials for Ministry of Education, College of Chemistry and Chemical Engineering, Northwest Normal University, Gansu (China)

    2013-11-15

    An efficient and eco-friendly method for hydrocyanation of sulfonylimines via one-pot two-step procedure using potassium hexacyanoferrate)II) as cyanide source, benzoyl chloride as a promoter, and potassium carbonate as a base is described. This protocol has the features of using nontoxic, nonvolatile and inexpensive cyanide source, high yield, and simple work-up procedure. (author)

  5. Studies of radiation fields of LCLS-II super conducting radio frequency cavities

    Science.gov (United States)

    Santana Leitner, M.; Ge, L.; Li, Z.; Xu, C.; Adolphsen, C.; Ross, M.; Carrasco, M.

    2016-09-01

    The Linac Coherent Light Source II (LCLS-II) will be a hard X-ray Free Electron Laser whose linac can deliver a 1.2 MW CW electron beam with bunch rates up to 1 MHz. To efficiently generate such a high power beam, Super-Conducting Radio-Frequency (SCRF) cavities will be installed in the upstream portion of the existing 3 km Linac at the SLAC National Accelerator Laboratory. The 9-cell niobium cavities will be cooled at 2K inside 35 cryomodules, each containing a string of eight of those cavities followed by a quadrupole. The strong electromagnetic fields in the SCRF cavities will extract electrons from the cavity walls that may be accelerated. Most such dark current will be deposited locally, although some electrons may reach several neighboring cryomodules, gaining substantial energy before they hit a collimator or other aperture. The power deposited by the field emitted electrons and the associated showers may pose radiation and machine protection issues at the cryomodules and also in other areas of the accelerator. Simulation of these effects is therefore crucial for the design of the machine. The in-house code Track3P was used to simulate field emitted electrons from the LCLS-II cavities, and a sophisticated 3D model of the cryomodules including all cavities was written to transport radiation with the Fluka Monte Carlo code, which was linked to Track3P through custom-made routines. This setup was used to compute power deposition in components, prompt and residual radiation fields, and radioisotope inventories.

  6. FEASIBILITY STUDY II OF A MUON BASED NEUTRINO SOURCE.

    Energy Technology Data Exchange (ETDEWEB)

    GALLARDO,J.C.; OZAKI,S.; PALMER,R.B.; ZISMAN,M.

    2001-06-30

    The concept of using a muon storage ring to provide a well characterized beam of muon and electron neutrinos (a Neutrino Factory) has been under study for a number of years now at various laboratories throughout the world. The physics program of a Neutrino Factoryis focused on the relatively unexplored neutrino sector. In conjunction with a detector located a suitable distance from the neutrino source, the facility would make valuable contributions to the study of neutrino masses and lepton mixing. A Neutrino Factory is expected to improve the measurement accuracy of sin{sup 2}(2{theta}{sub 23}) and {Delta}m{sup 2}{sub 32} and provide measurements of sin{sup 2}(2{theta}{sub 13}) and the sign of {Delta}m{sup 2}{sub 32}. It may also be able to measure CP violation in the lepton sector.

  7. Effects of Source Correlations on the Spectrum of Radiated Fields

    Science.gov (United States)

    1990-09-01

    directivltv Chapter 2 68 12 K. Kim and E. Wolf, "Non-radiating monochromatic sources and their fields", Opt. Commun. 59, 1-6 (1986). 13 The Jacobian of...Amer. 68 , 1597-1605 (1978). 15 R. Bracewell, The Fourier Transform and Its Applications (McGraw-Hill, New York, 1965), Chap. 6. 16 The method of...Ghatak and C.L. Metha, "Propagation of a partially coherent beam through selfoc fibers", Opt. Commun. 12, 333-337(1974). D. Marcuse , Light Transmission

  8. Inexpensive Open-Source Data Logging in the Field

    Science.gov (United States)

    Wickert, A. D.

    2013-12-01

    I present a general-purpose open-source field-capable data logger, which provides a mechanism to develop dense networks of inexpensive environmental sensors. This data logger was developed as a low-power variant of the Arduino open-source development system, and is named the ALog ("Arduino Logger") BottleLogger (it is slim enough to fit inside a Nalgene water bottle) version 1.0. It features an integrated high-precision real-time clock, SD card slot for high-volume data storage, and integrated power switching. The ALog can interface with sensors via six analog/digital pins, two digital pins, and one digital interrupt pin that can read event-based inputs, such as those from a tipping-bucket rain gauge. We have successfully tested the ALog BottleLogger with ultrasonic rangefinders (for water stage and snow accumulation and melt), temperature sensors, tipping-bucket rain gauges, soil moisture and water potential sensors, resistance-based tools to measure frost heave, and cameras that it triggers based on events. The source code for the ALog, including functions to interface with a a range of commercially-available sensors, is provided as an Arduino C++ library with example implementations. All schematics, circuit board layouts, and source code files are open-source and freely available under GNU GPL v3.0 and Creative Commons Attribution-ShareAlike 3.0 Unported licenses. Through this work, we hope to foster a community-driven movement to collect field environmental data on a budget that permits citizen-scientists and researchers from low-income countries to collect the same high-quality data as researchers in wealthy countries. These data can provide information about global change to managers, governments, scientists, and interested citizens worldwide. Watertight box with ALog BottleLogger data logger on the left and battery pack with 3 D cells on the right. Data can be collected for 3-5 years on one set of batteries.

  9. Alternative current source based Schottky contact with additional electric field

    Science.gov (United States)

    Mamedov, R. K.; Aslanova, A. R.

    2017-07-01

    Additional electric field (AEF) in the Schottky contacts (SC) that covered the peripheral contact region wide and the complete contact region narrow (as TMBS diode) SC. Under the influence of AEF is a redistribution of free electrons produced at certain temperatures of the semiconductor, and is formed the space charge region (SCR). As a result of the superposition of the electric fields SCR and AEF occurs the resulting electric field (REF). The REF is distributed along a straight line perpendicular to the contact surface, so that its intensity (and potential) has a minimum value on the metal surface and the maximum value at a great distance from the metal surface deep into the SCR. Under the influence of AEF as a sided force the metal becomes negative pole and semiconductor - positive pole, therefore, SC with AEF becomes an alternative current source (ACS). The Ni-nSi SC with different diameters (20-1000 μm) under the influence of the AEF as sided force have become ACS with electromotive force in the order of 0.1-1.0 mV, which are generated the electric current in the range of 10-9-10-7 A, flowing through the external resistance 1000 Ohm.

  10. Analytic solution of field distribution and demagnetization function of ideal hollow cylindrical field source

    Science.gov (United States)

    Xu, Xiaonong; Lu, Dingwei; Xu, Xibin; Yu, Yang; Gu, Min

    2017-09-01

    The Halbach type hollow cylindrical permanent magnet array (HCPMA) is a volume compact and energy conserved field source, which have attracted intense interests in many practical applications. Here, using the complex variable integration method based on the Biot-Savart Law (including current distributions inside the body and on the surfaces of magnet), we derive analytical field solutions to an ideal multipole HCPMA in entire space including the interior of magnet. The analytic field expression inside the array material is used to construct an analytic demagnetization function, with which we can explain the origin of demagnetization phenomena in HCPMA by taking into account an ideal magnetic hysteresis loop with finite coercivity. These analytical field expressions and demagnetization functions provide deeper insight into the nature of such permanent magnet array systems and offer guidance in designing optimized array system.

  11. New 20-cm radio-continuum study of the Small Magellanic Cloud, part II: Point sources

    Directory of Open Access Journals (Sweden)

    Wong G.F.

    2011-01-01

    Full Text Available We present a new catalogue of radio-continuum sources in the field of the Small Magellanic Cloud (SMC. This catalogue contains sources previously not found in 2370 MHz (λ=13 cm with sources found at 1400 MHz (λ=20 cm and 843 MHz (λ=36 cm. 45 sources have been detected at 13 cm, with 1560 sources at 20 cm created from new high sensitivity and resolution radio-continuum images of the SMC at 20 cm from paper I. We also created a 36 cm catalogue to which we listed 1689 radio-continuum sources.

  12. Cyclic Evolution of Coronal Fields from a Coupled Dynamo Potential-Field Source-Surface Model.

    Science.gov (United States)

    Dikpati, Mausumi; Suresh, Akshaya; Burkepile, Joan

    The structure of the Sun's corona varies with the solar-cycle phase, from a near spherical symmetry at solar maximum to an axial dipole at solar minimum. It is widely accepted that the large-scale coronal structure is governed by magnetic fields that are most likely generated by dynamo action in the solar interior. In order to understand the variation in coronal structure, we couple a potential-field source-surface model with a cyclic dynamo model. In this coupled model, the magnetic field inside the convection zone is governed by the dynamo equation; these dynamo-generated fields are extended from the photosphere to the corona using a potential-field source-surface model. Assuming axisymmetry, we take linear combinations of associated Legendre polynomials that match the more complex coronal structures. Choosing images of the global corona from the Mauna Loa Solar Observatory at each Carrington rotation over half a cycle (1986 - 1991), we compute the coefficients of the associated Legendre polynomials up to degree eight and compare with observations. We show that at minimum the dipole term dominates, but it fades as the cycle progresses; higher-order multipolar terms begin to dominate. The amplitudes of these terms are not exactly the same for the two limbs, indicating that there is a longitude dependence. While both the 1986 and the 1996 minimum coronas were dipolar, the minimum in 2008 was unusual, since there was a substantial departure from a dipole. We investigate the physical cause of this departure by including a North-South asymmetry in the surface source of the magnetic fields in our flux-transport dynamo model, and find that this asymmetry could be one of the reasons for departure from the dipole in the 2008 minimum.

  13. Search for extraterrestrial point sources of neutrinos with AMANDA-II

    CERN Document Server

    Ahrens, J; Barwick, S W; Becka, T; Becker, J K; Bernardini, E; Bertrand, D; Binon, Freddy G; Biron, A; Boersma, D J; Boser, S; Botner, O; Bouchta, A; Bouhali, O; Burgess, T; Carius, S; Castermans, T; Chen, A; Chirkin, D; Collin, B; Conrad, J; Cooley, J; Cowen, D F; Davour, A; De Clercq, C; De Young, T R; Desiati, P; Dewulf, J P; Ekstrom, P; Feser, T; Gaisser, T K; Ganugapati, R; Gaug, M; Geenen, H; Gerhardt, L; Goldschmidt, A; Gross, A; Hallgren, A; Halzen, F; Hanson, K; Hardtke, R; Harenberg, T; Hauschildt, T; Helbing, K; Hellwig, M; Herquet, P; Hill, G C; Hubert, D; Hughey, B; Hulth, P O; Hultqvist, K; Hundertmark, S; Jacobsen, J; Karle, A; Kestel, M; Köpke, L; Kowalski, M; Kühn, K; Lamoureux, J I; Leich, H; Leuthold, M J; Lindahl, P; Liubarsky, I; Madsen, J; Mandli, K; Marciniewski, P; Matis, H S; McParland, C P; Messarius, T; Minaeva, Y; Miocinovic, P; Morse, R; Munich, K; Nahnhauer, R; Neunhoffer, T; Niessen, P; Nygren, D R; Ögelman, H B; Olbrechts, P; Pérez de los Heros, C; Pohl, A C; Porrata, R; Price, P B; Przybylski, G T; Rawlins, K; Resconi, E; Rhode, W; Ribordy, M; Richter, S; Rodríguez-Martino, J; Sander, H G; Schinarakis, K; Schlenstedt, S; Schmidt, T; Schneider, D; Schwarz, R; Silvestri, A; Solarz, M; Spiczak, G M; Spiering, C; Stamatikos, M; Steele, D; Steffen, P; Stokstad, R G; Sulanke, K H; Taboada, I; Thollander, L; Tilav, S; Wagner, W; Walck, C; Wang, Y R; Wiebusch, C; Wiedemann, C; Wischnewski, R; Wissing, H; Woschnagg, K; Yodh, G B

    2004-01-01

    We present the results of a search for point sources of high energy neutrinos in the northern hemisphere using AMANDA-II data collected in the year 2000. Included are flux limits on several AGN blazars, microquasars, magnetars and other candidate neutrino sources. A search for excesses above a random background of cosmic-ray-induced atmospheric neutrinos and misreconstructed downgoing cosmic-ray muons reveals no statistically significant neutrino point sources. We show that AMANDA-II has achieved the sensitivity required to probe known TeV gamma-ray sources such as the blazar Markarian 501 in its 1997 flaring state at a level where neutrino and gamma-ray fluxes are equal.

  14. Asymptotics with a positive cosmological constant: II. Linear fields on de Sitter space-time

    CERN Document Server

    Ashtekar, Abhay; Kesavan, Aruna

    2015-01-01

    Linearized gravitational waves in de Sitter space-time are analyzed in detail to obtain guidance for constructing the theory of gravitational radiation in presence of a positive cosmological constant in full, nonlinear general relativity. Specifically: i) In the exact theory, the intrinsic geometry of $\\scri$ is often assumed to be conformally flat in order to reduce the asymptotic symmetry group from $\\Diff$ to the de Sitter group. Our {results show explicitly} that this condition is physically unreasonable; ii) We obtain expressions of energy-momentum and angular momentum fluxes carried by gravitational waves in terms of fields defined at $\\scrip$; iii) We argue that, although energy of linearized gravitational waves can be arbitrarily negative in general, gravitational waves emitted by physically reasonable sources carry positive energy; and, finally iv) We demonstrate that the flux formulas reduce to the familiar ones in Minkowski space-time in spite of the fact that the limit $\\Lambda \\to 0$ is discontin...

  15. Cortical current source connectivity by means of partial coherence fields

    CERN Document Server

    Pascual-Marqui, Roberto D; Valdes-Sosa, Pedro A; Bosch-Bayard, Jorge; Riera-Diaz, Jorge J

    2011-01-01

    An important field of research in functional neuroimaging is the discovery of integrated, distributed brain systems and networks, whose different regions need to work in unison for normal functioning. The EEG is a non-invasive technique that can provide information for massive connectivity analyses. Cortical signals of time varying electric neuronal activity can be estimated from the EEG. Although such techniques have very high time resolution, two cortical signals even at distant locations will appear to be highly similar due to the low spatial resolution nature of the EEG. In this study a method for eliminating the effect of common sources due to low spatial resolution is presented. It is based on an efficient estimation of the whole-cortex partial coherence matrix. Using as a starting point any linear EEG tomography that satisfies the EEG forward equation, it is shown that the generalized partial coherences for the cortical grey matter current density time series are invariant to the selected tomography. I...

  16. Strong soil source of carbonyl sulfide in an agricultural field

    Science.gov (United States)

    Maseyk, K. S.; Seibt, U.; Berry, J. A.; Billesbach, D. P.; Campbell, J.; Torn, M. S.

    2012-12-01

    A promising new approach to constrain biosphere-atmosphere carbon and water exchange is the use of carbonyl sulfide (COS). COS is taken up by leaves via the same pathway as CO2, leading to a close coupling of vegetation COS and CO2 fluxes during photosynthesis. Therefore it has been proposed that the gross fluxes of photosynthesis and respiration can be quantified through the concurrent measurements of COS and CO2. A necessary requirement for this approach at ecosystem and continental scales are estimates of soil COS fluxes. Soil is largely considered a sink for COS, but our knowledge of in situ soil COS fluxes remains very limited. We measured soil COS fluxes in a wheat field in Oklahoma from April to June 2012, using a novel combination of an automated soil chamber coupled to a COS laser analyzer. We provide the first continuous record of soil COS fluxes under natural conditions, and report on a phenomenon that has not been observed before. In contrast to the majority of published results, we found that the agricultural soil was a strong source of COS under most conditions during the campaign. The COS flux over the study period was highly correlated with soil temperature. Up to a soil temperature of around 15°C, the soil acted as a COS sink. Above 15°C, it acted a source of COS, with fluxes of up to 25 pmol m-2 s-1. To locate the source of the COS production, we investigated different soil components. Wheat roots were found to be emitting COS under all conditions. Root-free soil was a COS sink up to a soil temperature of around 25°C, but turned into a COS source at higher soil temperatures. We also observed COS production from the roots of several other species, indicating that this may be a widespread phenomenon. Using eddy covariance data of COS and CO2 that was collected concurrently with the soil measurements, we also demonstrate how the soil COS source can be taken into account when partitioning net ecosystem exchange into photosynthesis and respiration.

  17. The Seyfert II Nature of the IRAS Source FSC10214+4724

    Science.gov (United States)

    Eisenhardt, P.; Elston, R.; McCarthy, P.; Dickinson, M.; Spinrad, H.; Jannuzi, B.; Maloney, P.

    1993-05-01

    We (Elston et al. 1993) have observed the rest frame optical and UV spectra of the luminous, high redshift IRAS galaxy FSC10214+4724. We find the [NII]/Hα and [OIII]/Hβ emission line ratios to be typical of those found in Seyfert II galaxies. The large Hα /Hβ ratio suggests substantial reddening of the narrow line region. The rest-frame optical emission is unpolarized (P=2.6+/-3.0%). These properties are very similar to those of the infrared luminous galaxies found at lower redshift, suggesting that FSC10214+4724 is the luminous extreme of the same population. A deep 1.6microns image of the field shows FSC10214+4724 to be unresolved with two nearby companions and several other faint objects within 10('') of the point source. These could be a a foreground group of galaxies or galaxies physically associated with FSC10214+4724. This aggregate of objects may have contributed some of the far-infrared flux detected within the large beam of IRAS. If there is a foreground group gravitational lensing may contribute to the large luminosity of FSC10214+4724.

  18. Intense positron source at the Munich research reactor FRM-II

    CERN Document Server

    Hugenschmidt, C; Schreckenbach, K; Strasser, B; Koegel, G; Sperr, P; Triftshaeuser, W

    2002-01-01

    The principle and the design of the in-pile positron source at the new Munich research reactor FRM-II are presented. Absorption of high-energy prompt gamma-rays from thermal neutron capture in sup 1 sup 1 sup 3 Cd generates positrons by pair production. For this purpose, a cadmium cap is placed inside the tip of the inclined beam tube SR11 in the neutron field of the reactor, where an undisturbed thermal neutron flux up to 2 x 10 sup 1 sup 4 n cm sup - sup 2 s sup - sup 1 is expected. At this position the flux ratio of thermal to fast neutrons will be better than 10 sup 4. Monte Carlo calculations showed that a mean capture rate in cadmium between 4.5 and 6.0 x 10 sup 1 sup 3 n cm sup - sup 2 s sup - sup 1 can be expected. Inside the cadmium cap a structure of platinum foils is placed for converting gamma-radiation into positron-electron pairs. The heated foils also act as positron moderators to generate monoenergetic positrons. After acceleration to 5 keV a positron beam is formed by electric lenses and guid...

  19. Correlation functions in conformal Toda field theory II

    CERN Document Server

    Fateev, V A

    2009-01-01

    This is the second part of the paper 0709.3806v2. Here we show that three-point correlation function with one semi-degenerate field in Toda field theory as well as four-point correlation function with one completely degenerate and one semi-degenerate field can be represented by the finite dimensional integrals.

  20. The ultraluminous X-ray source HoII X-1: kinematic evidence of its escape from the cluster

    CERN Document Server

    Egorov, Oleg V; Moiseev, Alexei V

    2016-01-01

    We analyse the structure and kinematics of ionized gas in the vicinity of the ultraluminous X-ray source (ULX) HoII X-1 in the Holmberg II galaxy using observational data obtained with a scanning Fabry-Perot interferometer in the H$\\alpha$, [SII] and [OIII] emission lines at the Russian 6-m telescope. Decomposition of the line profiles allows us to identify the broad component of emission lines caused by the ULX action. We found evidence of an expanding superbubble around the young star cluster located in the studied region. We conclude that the blue-shifted 'arc' around the ULX observed in the line-of-sight velocity field may correspond to a bow shock caused by the ULX movement from that nearby young star cluster. If this interpretation is correct, it will be the first kinematic evidence of ULX's escape from their parent star clusters.

  1. FR II radio galaxies at low frequencies - I. Morphology, magnetic field strength and energetics

    NARCIS (Netherlands)

    Harwood, Jeremy J.; Croston, Judith H.; Intema, Huib T.; Stewart, Adam J.; Ineson, Judith; Hardcastle, Martin J.; Godfrey, Leith; Best, Philip; Brienza, Marisa; Heesen, Volker; Mahony, Elizabeth K.; Morganti, Raffaella; Murgia, Matteo; Orrú, Emanuela; Röttgering, Huub; Shulevski, Aleksandar; Wise, Michael W.

    2016-01-01

    Due to their steep spectra, low-frequency observations of Fanaroff-Riley type II (FR II) radio galaxies potentially provide key insights in to the morphology, energetics and spectrum of these powerful radio sources. However, limitations imposed by the previous generation of radio interferometers at

  2. A dynamical model for FR II type radio sources with terminated jet activity

    Science.gov (United States)

    Kuligowska, Elżbieta

    2017-02-01

    Context. The extension of the KDA analytical model of FR II-type source evolution originally assuming a continuum injection process in the jet-IGM interaction towards a case of the jet's termination is presented and briefly discussed. Aims: The dynamical evolution of FR II-type sources predicted with this extended model, hereafter referred to as KDA EXT, and its application to the chosen radio sources. Methods: Following the classical approach based on the source's continuous injection and self-similarity, I propose the effective formulae describing the length and luminosity evolution of the lobes during an absence of the jet flow, and present the resulting diagrams for the characteristics mentioned. Results: Using an algorithm based on the numerical integration of a modified formula for jet power, the KDA EXT model is fitted to three radio galaxies. Their predicted spectra are then compared to the observed spectra, proving that these fits are better than the best spectral fit provided by the original KDA model of the FR II-type sources dynamical evolution.

  3. Henselian valued quasilocal fields with totally indivisible value groups, II

    OpenAIRE

    Chipchakov, I. D.

    2010-01-01

    This paper characterizes the quasilocal fields from the class of Henselian valued fields with totally indivisible value groups, which possess finite separable extensions of nontrivial defect. We show that, for any prime number $q$, a divisible subgroup $T$ in the multiplicative group of complex numbers is realizable as the Brauer group of such a quasilocal field of residual characteristic $q$ unless $q = 2$ and the $2$-component of T$ is trivial.

  4. Ferroelectric plasma sources for NDCX-II and heavy ion drivers

    Energy Technology Data Exchange (ETDEWEB)

    Gilson, E.P., E-mail: egilson@pppl.gov [Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey, 08543 (United States); Davidson, R.C.; Efthimion, P.C.; Kaganovich, I.D. [Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey, 08543 (United States); Kwan, J.W.; Lidia, S.M.; Ni, P.A.; Roy, P.K.; Seidl, P.A.; Waldron, W.L. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California, 94720 (United States); Barnard, J.J.; Friedman, A. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California, 94550 (United States)

    2014-01-01

    A barium titanate ferroelectric cylindrical plasma source has been developed, tested and delivered for the Neutralized Drift Compression Experiment NDCX-II at Lawrence Berkeley National Laboratory (LBNL). The plasma source design is based on the successful design of the NDCX-I plasma source. A 7 kV pulse applied across the 3.8 mm-thick ceramic cylinder wall produces a large polarization surface charge density that leads to breakdown and plasma formation. The plasma that fills the NDCX-II drift section upstream of the final-focusing solenoid has a plasma number density exceeding 10{sup 10} cm{sup −3} and an electron temperature of several eV. The operating principle of the ferroelectric plasma source are reviewed and a detailed description of the installation plans is presented. The criteria for plasma sources with larger number density will be given, and concepts will be presented for plasma sources for driver applications. Plasma sources for drivers will need to be highly reliable, and operate at several Hz for millions of shots.

  5. Ferroelectric plasma sources for NDCX-II and heavy ion drivers

    Science.gov (United States)

    Gilson, E. P.; Davidson, R. C.; Efthimion, P. C.; Kaganovich, I. D.; Kwan, J. W.; Lidia, S. M.; Ni, P. A.; Roy, P. K.; Seidl, P. A.; Waldron, W. L.; Barnard, J. J.; Friedman, A.

    2014-01-01

    A barium titanate ferroelectric cylindrical plasma source has been developed, tested and delivered for the Neutralized Drift Compression Experiment NDCX-II at Lawrence Berkeley National Laboratory (LBNL). The plasma source design is based on the successful design of the NDCX-I plasma source. A 7 kV pulse applied across the 3.8 mm-thick ceramic cylinder wall produces a large polarization surface charge density that leads to breakdown and plasma formation. The plasma that fills the NDCX-II drift section upstream of the final-focusing solenoid has a plasma number density exceeding 1010 cm-3 and an electron temperature of several eV. The operating principle of the ferroelectric plasma source are reviewed and a detailed description of the installation plans is presented. The criteria for plasma sources with larger number density will be given, and concepts will be presented for plasma sources for driver applications. Plasma sources for drivers will need to be highly reliable, and operate at several Hz for millions of shots.

  6. MODE I AND MODE II CRACK TIP ASYMPTOTIC FIELDS WITH STRAIN GRADIENT EFFECTS

    Institute of Scientific and Technical Information of China (English)

    陈少华; 王自强

    2001-01-01

    The strain gradient effect becomes significant when the size of fracture process zone around a crack tip is comparable to the intrinsic material length l,typically of the order of microns. Using the new strain gradient deformation theory given by Chen and Wang, the asymptotic fields near a crack tip in an elastic-plastic material with strain gradient effects are investigated. It is established that the dominant strain field is irrotational. For mode I plane stress crack tip asymptotic field,the stress asymptotic field and the couple stress asymptotic field can not exist simultaneously. In the stress dominated asymptotic field, the angular distributions of stresses are consistent with the classical plane stress HRR field; In the couple stress dominated asymptotic field, the angular distributions of couple stresses are consistent with that obtained by Huang et al. For mode II plane stress and plane strain crack tip asymptotic fields, only the stress-dominated asymptotic fields exist. The couple stress asymptotic field is less singular than the stress asymptotic fields. The stress asymptotic fields are the same as mode II plane stress and plane strain HRR fields,respectively. The increase in stresses is not observed in strain gradient plasticity for mode I and mode II, because the present theory is based only on the rotational gradient of deformation and the crack tip asymptotic fields are irrotational and dominated by the stretching gradient.

  7. Reconstruction and prediction of multi-source acoustic field with the distributed source boundary point method based nearfield acoustic holography

    Institute of Scientific and Technical Information of China (English)

    BI; Chuanxing; CHEN; Jian; CHEN; Xinzhao

    2004-01-01

    In a multi-source acoustic field, the actual measured pressure is a scalar sum of pressures from all the sources. The pressure belonging to every source cannot be separated out with the existing techniques. Consequently, routine formulas cannot be used to reconstruct the acoustic source and predict the acoustic field directly. In this paper, a novel theoretical model of reconstruction and prediction of multi-source acoustic field in the distributed source boundary point method (DSBPM) based nearfield acoustic holography (NAH) is established. Three different methods, namely combination method with single surface measurement, combination method with multi-surface measurement and elimination method with multi-surface measurement, are proposed to realize the holographic reconstruction of sources. With these methods, the problem of reconstruction and prediction of acoustic field existing multiple coherent sources synchronously is solved effectively. Using the particular solutions constructed by the DSBPM to establish the vibro-acoustic transfer matrix, the calculation time, calculation precision and calculation stability are improved. These methods are valuable in localizing acoustic source and predicting acoustic field in engineering field.

  8. An Equivalent Source Method for Modelling the Global Lithospheric Magnetic Field

    DEFF Research Database (Denmark)

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

    We produce a new model of the global lithospheric magnetic field based on 3-component vector field observations at all latitudes from the CHAMP satellite using an equivalent source technique.......We produce a new model of the global lithospheric magnetic field based on 3-component vector field observations at all latitudes from the CHAMP satellite using an equivalent source technique....

  9. Positions of type II fundamental and harmonic sources in the 30-100 MHZ range

    Science.gov (United States)

    Sawant, H. S.; Gergely, T. E.; Kundu, M. R.

    1982-01-01

    An excellent example of a type III-V burst followed by a type II burst with fundamental and harmonic bands was observed on June 18, 1979 at the Clark Lake Radio Observatory. The observations are described in detail and their implications are discussed with regard to the problem of directionality with respect to the magnetic field lines of the collisionless MHD shock wave generated at the start of the flash phase. It is found that the positions of type III and type II (F) bursts at a number of frequencies are essentially the same, which implies that the shock responsible for the type II radiation follows the path of the type III exciter, that is, the shock propagates along the open field lines.

  10. Faraday Rotation from Magnesium II Absorbers towards Polarized Background Radio Sources

    CERN Document Server

    Farnes, J S; Corrigan, M E; Gaensler, B M

    2014-01-01

    Strong magnesium II (MgII) absorption lines in quasar spectra typically serve as a proxy for an intervening galaxy along the line of sight. Previous studies have found a correlation between the number of these MgII absorbers and the rotation measure (RM) at $\\approx5$ GHz. We cross-match a sample of 35,752 optically-identified non-intrinsic MgII absorption systems with 25,649 polarized background radio sources for which we have measurements of both the spectral index and RM at 1.4 GHz. We use the spectral index to split the resulting sample of 599 sources into flat-spectrum and steep-spectrum subsamples. We find that our flat-spectrum sample shows significant ($\\sim3.5\\sigma$) evidence for a correlation between MgII absorption and RM at 1.4 GHz, while our steep-spectrum sample shows no such correlation. We argue that such an effect cannot be explained by either luminosity or other observational effects, by evolution in another confounding variable, by wavelength-dependent polarization structure in an active g...

  11. Getting to the Source: a Survey of Quantitative Data Sources Available to the Everyday Librarian: Part II: Data Sources from Specific Library Applications

    Directory of Open Access Journals (Sweden)

    Lisa Goddard

    2007-03-01

    Full Text Available This is the second part of a two-part article that provides a survey of data sources which are likely to be immediately available to the typical practitioner who wishes to engage in statistical analysis of collections and services within his or her own library. Part I outlines the data elements which can be extracted from web server logs, and discusses web log analysis tools. Part II looks at logs, reports, and data sources from proxy servers, resource vendors, link resolvers, federated search engines, institutional repositories, electronic reference services, and the integrated library system.

  12. RadSTraM: Radiological Source Tracking and Monitoring, Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Tracy A [ORNL; Walker, Randy M [ORNL; Hill, David E [ORNL; Gross, Ian G [ORNL; Smith, Cyrus M [ORNL; Abercrombie, Robert K [ORNL

    2008-12-01

    This report focuses on the technical information gained from the Radiological Source Tracking and Monitoring (RadSTraM) Phase II investigation and its implications. The intent of the RadSTraM project was to determine the feasibility of tracking radioactive materials in commerce, particularly International Atomic Energy Agency (IAEA) Category 3 and 4 materials. Specifically, Phase II of the project addressed tracking radiological medical isotopes in commerce. These categories of materials are susceptible to loss or theft but the problem is not being addressed by other agencies.

  13. Analysis of the wake field effects in the PEP-II storage rings with extremely high currents

    Energy Technology Data Exchange (ETDEWEB)

    Novokhatski, A., E-mail: novo@slac.stanford.edu; Seeman, J.; Sullivan, M.

    2014-01-21

    We present the history and analysis of different wake field effects throughout the operational life of the PEP-II SLAC B-factory. Although the impedance of the high and low energy rings is small, the intense high-current beams generated a lot of power. The effects from these wake fields are: heating and damage of vacuum beam chamber elements like RF seals, vacuum valves, shielded bellows, BPM buttons and ceramic tiles; vacuum spikes, vacuum instabilities and high detector background; and beam longitudinal and transverse instabilities. We also discuss the methods used to eliminate these effects. Results of this analysis and the PEP-II experience may be very useful in the design of new storage rings and light sources.

  14. Analysis of the wake field effects in the PEP-II storage rings with extremely high currents

    Science.gov (United States)

    Novokhatski, A.; Seeman, J.; Sullivan, M.

    2014-01-01

    We present the history and analysis of different wake field effects throughout the operational life of the PEP-II SLAC B-factory. Although the impedance of the high and low energy rings is small, the intense high-current beams generated a lot of power. The effects from these wake fields are: heating and damage of vacuum beam chamber elements like RF seals, vacuum valves, shielded bellows, BPM buttons and ceramic tiles; vacuum spikes, vacuum instabilities and high detector background; and beam longitudinal and transverse instabilities. We also discuss the methods used to eliminate these effects. Results of this analysis and the PEP-II experience may be very useful in the design of new storage rings and light sources.

  15. Modern Quantum Field Theory II - Proceeeings of the International Colloquium

    Science.gov (United States)

    Das, S. R.; Mandal, G.; Mukhi, S.; Wadia, S. R.

    1995-08-01

    The Table of Contents for the book is as follows: * Foreword * 1. Black Holes and Quantum Gravity * Quantum Black Holes and the Problem of Time * Black Hole Entropy and the Semiclassical Approximation * Entropy and Information Loss in Two Dimensions * Strings on a Cone and Black Hole Entropy (Abstract) * Boundary Dynamics, Black Holes and Spacetime Fluctuations in Dilation Gravity (Abstract) * Pair Creation of Black Holes (Abstract) * A Brief View of 2-Dim. String Theory and Black Holes (Abstract) * 2. String Theory * Non-Abelian Duality in WZW Models * Operators and Correlation Functions in c ≤ 1 String Theory * New Symmetries in String Theory * A Look at the Discretized Superstring Using Random Matrices * The Nested BRST Structure of Wn-Symmetries * Landau-Ginzburg Model for a Critical Topological String (Abstract) * On the Geometry of Wn Gravity (Abstract) * O(d, d) Tranformations, Marginal Deformations and the Coset Construction in WZNW Models (Abstract) * Nonperturbative Effects and Multicritical Behaviour of c = 1 Matrix Model (Abstract) * Singular Limits and String Solutions (Abstract) * BV Algebra on the Moduli Spaces of Riemann Surfaces and String Field Theory (Abstract) * 3. Condensed Matter and Statistical Mechanics * Stochastic Dynamics in a Deposition-Evaporation Model on a Line * Models with Inverse-Square Interactions: Conjectured Dynamical Correlation Functions of the Calogero-Sutherland Model at Rational Couplings * Turbulence and Generic Scale Invariance * Singular Perturbation Approach to Phase Ordering Dynamics * Kinetics of Diffusion-Controlled and Ballistically-Controlled Reactions * Field Theory of a Frustrated Heisenberg Spin Chain * FQHE Physics in Relativistic Field Theories * Importance of Initial Conditions in Determining the Dynamical Class of Cellular Automata (Abstract) * Do Hard-Core Bosons Exhibit Quantum Hall Effect? (Abstract) * Hysteresis in Ferromagnets * 4. Fundamental Aspects of Quantum Mechanics and Quantum Field Theory

  16. Dispersion of Magnetic Fields in Molecular Clouds. II

    CERN Document Server

    Houde, Martin; Hildebrand, Roger H; Chitsazzadeh, Shadi; Kirby, Larry

    2009-01-01

    We expand our study on the dispersion of polarization angles in molecular clouds. We show how the effect of signal integration through the thickness of the cloud as well as across the area subtended by the telescope beam inherent to dust continuum measurements can be incorporated in our analysis to correctly account for its effect on the measured angular dispersion and inferred turbulent to large-scale magnetic field strength ratio. We further show how to evaluate the turbulent magnetic field correlation scale from polarization data of sufficient spatial resolution and high enough spatial sampling rate. We apply our results to the molecular cloud OMC-1, where we find a turbulent correlation length of approximately 16 mpc, a turbulent to large-scale magnetic field strength ratio of approximately 0.5, and a plane-of-the-sky large-scale magnetic field strength of approximately 0.76 mG.

  17. Unconstrained Higher Spins of Mixed Symmetry. II. Fermi Fields

    CERN Document Server

    Campoleoni, Andrea; Mourad, Jihad; Sagnotti, Augusto

    2010-01-01

    This paper is a sequel of arXiv:0810.4350 [hep-th], and is also devoted to the local "metric-like" unconstrained Lagrangians and field equations for higher-spin fields of mixed symmetry in flat space. Here we complete the previous constrained on-shell formulation of Labastida for Fermi fields, deriving the corresponding constrained Lagrangians both via the Bianchi identities and via the requirement of self-adjointness. We also describe two types of unconstrained Lagrangian formulations: a "minimal" one, containing higher derivatives of the compensator fields, and another non-minimal one, containing only one-derivative terms. We identify classes of these systems that are invariant under Weyl-like symmetry transformations.

  18. Unconstrained higher spins of mixed symmetry II. Fermi fields

    Energy Technology Data Exchange (ETDEWEB)

    Campoleoni, A., E-mail: a.campoleoni@sns.i [Scuola Normale Superiore and INFN, Piazza dei Cavalieri, 7, I-56126 Pisa (Italy); Francia, D., E-mail: francia@apc.univ-paris7.f [AstroParticule et Cosmologie (APC), Universite Paris VII - Campus Paris Rive Gauche, 10, rue Alice Domon et Leonie Duquet, F-75205 Paris Cedex 13 (France); Mourad, J., E-mail: mourad@apc.univ-paris7.f [AstroParticule et Cosmologie (APC), Universite Paris VII - Campus Paris Rive Gauche, 10, rue Alice Domon et Leonie Duquet, F-75205 Paris Cedex 13 (France); Sagnotti, A., E-mail: sagnotti@sns.i [Scuola Normale Superiore and INFN, Piazza dei Cavalieri, 7, I-56126 Pisa (Italy)

    2010-04-01

    This paper is a sequel of [A. Campoleoni, D. Francia, J. Mourad, A. Sagnotti, Nucl. Phys. B 815 (2009) 289, (arXiv:0810.4350 [hep-th])], and is also devoted to the local 'metric-like' unconstrained Lagrangians and field equations for higher-spin fields of mixed symmetry in flat space. Here we complete the previous constrained on-shell formulation of Labastida for Fermi fields, deriving the corresponding constrained Lagrangians both via the Bianchi identities and via the requirement of self-adjointness. We also describe two types of unconstrained Lagrangian formulations: a 'minimal' one, containing higher derivatives of the compensator fields, and another non-minimal one, containing only one-derivative terms. We identify classes of these systems that are invariant under Weyl-like symmetry transformations.

  19. Acceleration and Particle Field Interactions of Cosmic Rays II: Calculations

    CERN Document Server

    Tawfik, A; Ghoneim, M T; Hady, A

    2010-01-01

    Based on the generic acceleration model, which suggests different types of electromagnetic interactions between the cosmic charged particles and the different configurations of the electromagnetic (plasma) fields, the ultra high energy cosmic rays are studied. The plasma fields are assumed to vary, spatially and temporally. The well-known Fermi accelerations are excluded. Seeking for simplicity, it is assumed that the energy loss due to different physical processes is negligibly small. The energy available to the plasma sector is calculated in four types of electromagnetic fields. It has been found that the drift in a time--varying magnetic field is extremely energetic. The energy scale widely exceeds the Greisen-Zatsepin-Kuzmin (GZK) cutoff. The polarization drift in a time--varying electric field is also able to raise the energy of cosmic rays to an extreme value. It can be compared with the Hillas mechanism. The drift in a spatially--varying magnetic field is almost as strong as the polarization drift. The...

  20. Monoenergetic positron beam at the reactor based positron source at FRM-II

    Science.gov (United States)

    Hugenschmidt, C.; Kögel, G.; Repper, R.; Schreckenbach, K.; Sperr, P.; Straßer, B.; Triftshäuser, W.

    2002-05-01

    The principle of the in-pile positron source at the Munich research reactor FRM-II is based on absorption of high energy prompt γ-rays from thermal neutron capture in 113Cd. For this purpose, a cadmium cap is placed inside the tip of the inclined beam tube SR-11 in the moderator tank of the reactor, where an undisturbed thermal neutron flux up to 2×10 14n cm-2 s-1 is expected. Inside the cadmium cap a structure of platinum foils is placed for converting high energy γ-radiation into positron-electron pairs. Due to the negative positron work function, moderation in annealed platinum leads to emission of monoenergetic positrons. Therefore, platinum will also be used as moderator, since its moderation property seems to yield long-term stability under reactor conditions and it is much easier to handle than tungsten. Model calculations were performed with SIMION-7.0w to optimise geometry and potential of Pt-foils and electrical lenses. It could be shown that the potentials between the Pt-foils must be chosen in the range of 1-10 V to extract moderated positrons. After successive acceleration to 5 keV by four electrical lenses the beam is magnetically guided in a solenoid field of 7.5 mT resulting in a beam diameter of about 25 mm. An intensity of about 10 10 slow positrons per second is expected in the primary positron beam. Outside of the reactor shield a W(1 0 0) single crystal remoderation stage will lead to an improvement of the positron beam brilliance before the positrons are guided to the experimental facilities.

  1. The possible detection of high redshift Type II QSOs in deep fields

    OpenAIRE

    Meiksin, Avery

    2005-01-01

    The colours of high redshift Type II QSOs are synthesized from observations of moderate redshift systems. It is shown that Type II QSOs are comparable to starbursts in their success at matching the colours of z_850-dropouts and i_775-drops in the Hubble Ultra Deep Field, and more naturally account for the bluest objects detected. Type II QSOs may also account for some of the i_775-drops detected in the GOODS fields. It is shown that by combining imaging data from the Hubble Space Telescope an...

  2. Source Identification Of Airborne Antimony On The Basis Of The Field Monitoring And The Source Profiling

    Science.gov (United States)

    Iijima, A.; Sato, K.; Fujitani, Y.; Fujimori, E.; Tanabe, K.; Ohara, T.; Shimoda, M.; Kozawa, K.; Furuta, N.

    2008-12-01

    The results of the long-term monitoring of airborne particulate matter (APM) in Tokyo indicated that APM have been extremely enriched with antimony (Sb) compared to crustal composition. This observation suggests that the airborne Sb is distinctly derived from human activities. According to the material flow analysis, automotive brake abrasion dust and fly ash from waste incinerator were suspected as the significant Sb sources. To clarify the emission sources of the airborne Sb, elemental composition, particle size distribution, and morphological profiles of dust particles collected from two possible emission sources were characterized and compared to the field observation data. Brake abrasion dust samples were generated by using a brake dynamometer. During the abrasion test, particle size distribution was measured by an aerodynamic particle sizer spectrometer. Concurrently, size- classified dust particles were collected by an Andersen type air sampler. Fly ash samples were collected from several municipal waste incinerators, and the bulk ash samples were re-dispersed into an enclosed chamber. The measurement of particle size distribution and the collection of size-classified ash particles were conducted by the same methodologies as described previously. Field observations of APM were performed at a roadside site and a residential site by using an Andersen type air sampler. Chemical analyses of metallic elements were performed by an inductively coupled plasma atomic emission spectrometry and an inductively coupled plasma mass spectrometr. Morphological profiling of the individual particle was conducted by a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. High concentration of Sb was detected from both of two possible sources. Particularly, Sb concentrations in a brake abrasion dust were extremely high compared to that in an ambient APM, suggesting that airborne Sb observed at the roadside might have been largely derived from

  3. High average power CO II laser MOPA system for Tin target LPP EUV light source

    Science.gov (United States)

    Ariga, Tatsuya; Hoshino, Hideo; Endo, Akira

    2007-02-01

    Extreme ultraviolet lithography (EUVL) is the candidate for next generation lithography to be introduced by the semiconductor industry to HVM (high volume manufacturing) in 2013. The power of the EUVL light source has to be at least 115W at a wavelength of 13.5nm. A laser produced plasma (LPP) is the main candidate for this light source but a cost effective laser driver is the key requirement for the realization of this concept. We are currently developing a high power and high repetition rate CO II laser system to achieve 50 W intermediate focus EUV power with a Tin droplet target. We have achieved CE of 2.8% with solid Tin wire target by a transversely excited atmospheric (TEA) CO II laser MOPA system with pulse width, pulse energy and pulse repetition rate as 10~15 ns, 30 mJ and 10 Hz, respectively. A CO II laser system with a short pulse length less than 15 ns, a nominal average power of a few kW, and a repetition rate of 100 kHz, based on RF-excited, fast axial flow CO II laser amplifiers is under development. Output power of about 3 kW has been achieved with a pulse length of 15 ns at 130 kHz repletion rate in a small signal amplification condition with P(20) single line. The phase distortion of the laser beam after amplification is negligible and the beam can be focused to about 150μm diameter in 1/e2. The CO II laser system is reported on short pulse amplification performance using RF-excited fast axial flow lasers as amplifiers. And the CO II laser average output power scaling is shown towards 5~10 kW with pulse width of 15 ns from a MOPA system.

  4. CCD surface photometry of radio galaxies: Pt. 1. FR class I and II sources

    Energy Technology Data Exchange (ETDEWEB)

    Owen, F.N.; Laing, R.A.

    1989-05-01

    CCD surface photometry of 47 radio galaxies in the R-band is reported. The goal of the programme is to study the relationship of the properties of the parent galaxies to the radio structure and, in particular, to look for differences between Fanaroff and Riley (FR) class I and II sources. In order to clarify some ambiguous cases in the FR classification, we define Classical Double, Twin Jet and Fat Double sources. We describe our definitions of these three classes and their relation to the FR classification. (author).

  5. Search for Point Sources of High Energy Neutrinos with Final Data from AMANDA-II

    CERN Document Server

    Abbasi, R; Adams, J; Ahlers, M; Ahrens, J; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Baret, B; Barwick, S W; Bay, R; Bazo Alba, J L; Beattie, K; Becka, T; Becker, J K; Becker, K H; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Blaufuss, E; Boersma, D J; Bohm, C; Bolmont, J; Boser, S; Botner, O; Braun, J; Breder, D; Burgess, T; Castermans, T; Chirkin, D; Christy, B; Clem, J; Cowen, D F; D'Agostino, M V; Danninger, M; Davour, A; Day, C T; Depaepe, O; De Clercq, C; Demirors, L; Descamps, F; Desiati, P; De Vries-Uiterweerd, G; De Young, T; Díaz-Veléz, J C; Dreyer, J; Dumm, J P; Duvoort, M R; Edwards, W R; Ehrlich, R; Eisch, J; Ellsworth, R W; Engdegard, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Filimonov, K; Finley, C; Foerster, M M; Fox, B D; Franckowiak, A; Franke, R; Gaisser, T K; Gallagher, J; Ganugapati, R; Gerhardt, L; Gladstone, L; Goldschmidt, A; Goodman, J A; Gozzini, R; Grant, D; Griesel, T; Gro, A; Grullon, S; Gunasingha, R M; Gurtner, M; Ha, C; Hallgren, A; Halzen, F; Han, K; Hanson, K; Hardtke, R; Hasegawa, Y; Heise, J; Helbing, K; Hellwig, M; Herquet, P; Hickford, S; Hill, G C; Hodges, J; Hoffman, K D; Hoshina, K; Hubert, D; Huelsnitz, W; Hughey, B; Hul, J P; Hulth, P O; Hultqvist, K; Hundertmark, S; Hussain, S; Imlay, R L; Inaba, M; Ishihara, A; Jacobsen, J; Japaridze, G S; Johansson, H; Joseph, J M; Kampert, K H; Kappes, A; Karg, T; Karle, A; Kawai, H; Kelley, J L; Kiryluk, J; Kislat, F; Klein, S R; Klepser, S; Kohnen, G; Kolanoski, H; Köpke, L; Kowalski, M; Kowarik, T; Krasberg, M; Kühn, K; Kuwabara, T; Labare, M; Laihem, K; Landsman, H; Lauer, R; Leich, H; Leier, D; Lewis, C; Lucke, A; Lundberg, J; Lunemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McParland, C P; Meagher, K; Meli, A; Merck, M; Messarius, T; Mészáros, P; Miyamoto, H; Mohr, A; Montaruli, T; Morse, R; Movit, S M; Munich, K; Nahnhauer, R; Nam, J W; Nieen, P; Nygren, D R; Odrowski, S; Olivas, A; Olivo, M; Ono, M; Panknin, S; Patton, S; Pérez de los Heros, C; Petrovic, J; Piegsa, A; Pieloth, D; Pohl, A C; Porrata, R; Potthoff, N; Pretz, J; Price, P B; Przybylski, G T; Rawlins, K; Razzaque, S; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Rizzo, A; Robbins, W J; Rodríguez, J; Roth, P; Rothmaier, F; Rott, C; Roucelle, C; Rutledge, D; Ryckbosch, D; Sander, H G; Sarkar, S; Satalecka, K; Schlenstedt, S; Schmidt, T; Schneider, D; Schultz, O; Seckel, D; Semburg, B; Seo, S H; Sestayo, Y; Seunarine, S; Silvestri, A; Smith, A J; Song, C; Spiczak, G M; Spiering, C; Stanev, T; Stezelberger, T; Stokstad, R G; Stoufer, M C; Stoyanov, S; Strahler, E A; Straszheim, T; Sulanke, K H; Sullivan, G W; Swillens, Q; Taboada, I; Tarasova, O; Tepe, A; Ter-Antonyan, S; Tilav, S; Tluczykont, M; Toale, P A; Tosi, D; Turcan, D; van Eijndhoven, N; Vandenbroucke, J; Van Overloop, A; Viscomi, V; Vogt, C; Voigt, B; Walck, C; Waldenmaier, T; Walter, M; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebusch, C H; Wiedemann, C; Wikström, G; Williams, D R; Wischnewski, R; Wissing, H; Woschnagg, K; Xu, X W; Yodh, G; Yoshida, S

    2008-01-01

    We present a search for point sources of high energy neutrinos using 3.8 years of data recorded by the AMANDA-II neutrino telescope during 2000-2006. Applying muon track reconstruction and quality criteria, we select 6595 candidate events, predominantly from atmospheric neutrinos. Our search reveals no indications of a neutrino point source. We place the most stringent limits to date on E$^{-2}$ neutrino fluxes from points in the Northern Sky, with an average upper limit of E$^{2}\\Phi_{\

  6. Simultaneous observation of water and class I methanol masers toward class II methanol maser sources

    CERN Document Server

    Kang, Hyunwoo; Byun, Do-Young; Lee, Seokho; Park, Yong-Sun

    2015-01-01

    We present a simultaneous single-dish survey of 22 GHz water maser and 44 GHz and 95 GHz class I methanol masers toward 77 6.7 GHz class II methanol maser sources, which were selected from the Arecibo methanol maser Galactic plane survey (AMGPS) catalog.Water maser emission is detected in 39 (51%) sources, of which 15 are new detections. Methanol maser emission at 44 GHz and 95 GHz is found in 25 (32%) and 19 (25%) sources, of which 21 and 13 sources are newly detected, respectively. We find 4 high-velocity (> 30 km/s) water maser sources, including 3 dominant blue- or redshifted outflows.The 95 GHz masers always appear with the 44 GHz maser emission. They are strongly correlated with 44 GHz masers in velocity, flux density, and luminosity, while they are not correlated with either water or 6.7 GHz class II methanol masers. The average peak flux density ratio of 95 GHz to 44 GHz masers is close to unity, which is two times higher than previous estimates. The flux densities of class I methanol masers are more ...

  7. Observations of the Hubble Deep Field with the Infrared Space Observatory .4. Association of sources with Hubble Deep Field galaxies

    DEFF Research Database (Denmark)

    Mann, R.G.; Oliver, S.J.; Serjeant, S.B.G.

    1997-01-01

    We discuss the identification of sources detected by the Infrared Space Observatory (ISO) at 6.7 and 15 mu m in the Hubble Deep Field (HDF) region. We conservatively associate ISO sources with objects in existing optical and near-infrared HDF catalogues using the likelihood ratio method, confirming...... these results (and, in one case, clarifying them) with independent visual searches, We find 15 ISO sources to be reliably associated with bright [I-814(AB) Hubble Flanking Fields (10 galaxies...

  8. Observations of the Hubble Deep Field with the Infrared Space Observatory .4. Association of sources with Hubble Deep Field galaxies

    DEFF Research Database (Denmark)

    Mann, R.G.; Oliver, S.J.; Serjeant, S.B.G.;

    1997-01-01

    We discuss the identification of sources detected by the Infrared Space Observatory (ISO) at 6.7 and 15 mu m in the Hubble Deep Field (HDF) region. We conservatively associate ISO sources with objects in existing optical and near-infrared HDF catalogues using the likelihood ratio method, confirming...... these results (and, in one case, clarifying them) with independent visual searches, We find 15 ISO sources to be reliably associated with bright [I-814(AB) Hubble Flanking Fields (10 galaxies...

  9. Worldline approach to vector and antisymmetric tensor fields II

    Science.gov (United States)

    Bastianelli, Fiorenzo; Benincasa, Paolo; Giombi, Simone

    2005-10-01

    We extend the worldline description of vector and antisymmetric tensor fields coupled to gravity to the massive case. In particular, we derive a worldline path integral representation for the one-loop effective action of a massive antisymmetric tensor field of rank p (a massive p-form) whose dynamics is dictated by a standard Proca-like lagrangian coupled to a background metric. This effective action can be computed in a proper time expansion to obtain the corresponding Seeley-DeWitt coefficients a0, a1, a2. The worldline approach immediately shows that these coefficients are derived from the massless ones by the simple shift D→D+1, where D is the spacetime dimension. Also, the worldline representation makes it simple to derive exact duality relations. Finally, we use such a representation to calculate the one-loop contribution to the graviton self-energy due to both massless and massive antisymmetric tensor fields of arbitrary rank, generalizing results already known for the massless spin 1 field (the photon).

  10. Worldline approach to vector and antisymmetric tensor fields II

    Energy Technology Data Exchange (ETDEWEB)

    Bastianelli, Fiorenzo [Dipartimento di Fisica, Universita di Bologna (Italy); INFN, Sezione di Bologna, Via Irnerio 46, I-40126 Bologna (Italy); Benincasa, Paolo [Department of Applied Mathematics, University of Western Ontario, Middlesex College, London, ON, N6A 5B7 (Canada); Giombi, Simone [C.N. Yang Institute for Theoretical Physics, State University of New York at Stony Brook, Stony Brook, NY 11794-3840 (United States)

    2005-10-15

    We extend the worldline description of vector and antisymmetric tensor fields coupled to gravity to the massive case. In particular, we derive a worldline path integral representation for the one-loop effective action of a massive antisymmetric tensor field of rank p (a massive p-form) whose dynamics is dictated by a standard Proca-like lagrangian coupled to a background metric. This effective action can be computed in a proper time expansion to obtain the corresponding Seeley-DeWitt coefficients a{sub 0}, a{sub 1}, a{sub 2}. The worldline approach immediately shows that these coefficients are derived from the massless ones by the simple shift D{yields}D+1, where D is the spacetime dimension. Also, the worldline representation makes it simple to derive exact duality relations. Finally, we use such a representation to calculate the one-loop contribution to the graviton self-energy due to both massless and massive antisymmetric tensor fields of arbitrary rank, generalizing results already known for the massless spin 1 field (the photon)

  11. Worldline approach to vector and antisymmetric tensor fields II

    CERN Document Server

    Bastianelli, F; Giombi, S; Bastianelli, Fiorenzo; Benincasa, Paolo; Giombi, Simone

    2005-01-01

    We extend the worldline description of vector and antisymmetric tensor fields coupled to gravity to the massive case. In particular, we derive a worldline path integral representation for the one-loop effective action of a massive antisymmetric tensor field of rank p (a massive p-form) whose dynamics is dictated by a standard Proca-like lagrangian coupled to a background metric. This effective action can be computed in a proper time expansion to obtain the corresponding Seeley-DeWitt coefficients a0, a1, a2. The worldline approach immediately shows that these coefficients are derived from the massless ones by the simple shift D -> D+1, where D is the spacetime dimension. Also, the worldline representation makes it simple to derive exact duality relations. Finally, we use such a representation to calculate the one-loop contribution to the graviton self-energy due to both massless and massive antisymmetric tensor fields of arbitrary rank, generalizing results already known for the massless spin 1 field (the pho...

  12. New gamma irradiation source at the research reactor Muenchen FRM II; Neue Gamma-Bestrahlungsanlage am Forschungsreaktor Muenchen FRM II

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Gerstenberg, H.; Lichtenstein, K.; Tralmer, F.L.; Zill, V.; Neuhaus, I. [Technische Univ. Muenchen, Garching (DE). Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II)

    2009-07-01

    The new research reactor FRM II is a high-performance neutron source. A new gamma irradiation line for high-intensity gamma radiation is planned in spent fuel elements including a heating system that will allow irradiation at temperatures up to 150 C. The design concept considers the experimental boundary conditions, i.e. irradiation inhomogeneity and sample temperatures, but also the spent fuel element safety. The neutron flux was measured in two spent fuel elements with decay times of 90 and 450 days, respectively. A significant neutron activation of the irradiation samples can be excluded. The dose rate profile in the spent fuel element was measured with a special measuring device. The irradiation facility will be started in 2009. An first research program concerning microstructure investigations of gamma irradiated rock salt is described.

  13. Separation of radiation from two sources from their known radiated sum field

    DEFF Research Database (Denmark)

    Laitinen, Tommi; Pivnenko, Sergey

    2011-01-01

    This paper presents a technique for complete and exact separation of the radiated fields of two sources (at the same frequency) from the knowledge of their radiated sum field. The two sources can be arbitrary but it must be possible to enclose the sources inside their own non-intersecting minimum...

  14. Grassmann phase space methods for fermions. II. Field theory

    Energy Technology Data Exchange (ETDEWEB)

    Dalton, B.J., E-mail: bdalton@swin.edu.au [Centre for Quantum and Optical Science, Swinburne University of Technology, Melbourne, Victoria 3122 (Australia); Jeffers, J. [Department of Physics, University of Strathclyde, Glasgow G4ONG (United Kingdom); Barnett, S.M. [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2017-02-15

    In both quantum optics and cold atom physics, the behaviour of bosonic photons and atoms is often treated using phase space methods, where mode annihilation and creation operators are represented by c-number phase space variables, with the density operator equivalent to a distribution function of these variables. The anti-commutation rules for fermion annihilation, creation operators suggests the possibility of using anti-commuting Grassmann variables to represent these operators. However, in spite of the seminal work by Cahill and Glauber and a few applications, the use of Grassmann phase space methods in quantum-atom optics to treat fermionic systems is rather rare, though fermion coherent states using Grassmann variables are widely used in particle physics. This paper presents a phase space theory for fermion systems based on distribution functionals, which replace the density operator and involve Grassmann fields representing anti-commuting fermion field annihilation, creation operators. It is an extension of a previous phase space theory paper for fermions (Paper I) based on separate modes, in which the density operator is replaced by a distribution function depending on Grassmann phase space variables which represent the mode annihilation and creation operators. This further development of the theory is important for the situation when large numbers of fermions are involved, resulting in too many modes to treat separately. Here Grassmann fields, distribution functionals, functional Fokker–Planck equations and Ito stochastic field equations are involved. Typical applications to a trapped Fermi gas of interacting spin 1/2 fermionic atoms and to multi-component Fermi gases with non-zero range interactions are presented, showing that the Ito stochastic field equations are local in these cases. For the spin 1/2 case we also show how simple solutions can be obtained both for the untrapped case and for an optical lattice trapping potential.

  15. Unconventional superconductors under a rotating magnetic field. II. Thermal transport

    Science.gov (United States)

    Vorontsov, A. B.; Vekhter, I.

    2007-06-01

    We present a microscopic approach to the calculations of thermal conductivity in unconventional superconductors for a wide range of temperatures and magnetic fields. Our work employs the nonequilibrium Keldysh formulation of the quasiclassical theory. We solve the transport equations using a variation of the Brandt-Pesch-Tewordt method that accounts for the quasiparticle scattering on vortices. We focus on the dependence of the thermal conductivity on the direction of the field with the respect to the nodes of the order parameter, and discuss it in the context of experiments aiming to determine the shape of the gap from such anisotropy measurements. We consider quasi-two-dimensional Fermi surfaces with vertical line nodes and use our analysis to establish the location of gap nodes in heavy-fermion CeCoIn5 and the organic superconductor κ-(BEDT-TTF)2Cu(NCS)2 .

  16. High-field Faraday rotation in II-VI-based semimagnetic semiconductors

    NARCIS (Netherlands)

    Savchuk, AI; Fediv, [No Value; Nikitin, PI; Perrone, A; Tatzenko, OM; Platonov, VV

    1998-01-01

    The effects of d-d exchange interaction have been studied by measuring high-field Faraday rotation in II-VI-based semimagnetic semiconductors. For Cd1-xMnxTe crystals with x = 0.43 and at room temperature a saturation in magnetic field dependence of the Faraday rotation has been observed. In the cas

  17. Quantum backreaction (Casimir) effect. II. Scalar and electromagnetic fields

    CERN Document Server

    Herdegen, A

    2005-01-01

    Casimir effect in most general terms may be understood as a backreaction of a quantum system causing an adiabatic change of the external conditions under which it is placed. This paper is the second installment of a work scrutinizing this effect with the use of algebraic methods in quantum theory. The general scheme worked out in the first part is applied here to the discussion of particular models. We consider models of the quantum scalar field subject to external interaction with ``softened'' Dirichlet or Neumann boundary conditions on two parallel planes. We show that the case of electromagnetic field with softened perfect conductor conditions on the planes may be reduced to the other two. The ``softening'' is implemented on the level of the dynamics, and is not imposed ad hoc, as is usual in most treatments, on the level of observables. We calculate formulas for the backreaction energy in these models. We find that the common belief that for electromagnetic field the backreaction force tends to the strict...

  18. Modeling transducer impulse responses for predicting calibrated pressure pulses with the ultrasound simulation program Field II

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2010-01-01

    FIELD II is a simulation software capable of predicting the field pressure in front of transducers having any complicated geometry. A calibrated prediction with this program is, however, dependent on an exact voltage-to-surface acceleration impulse response of the transducer. Such impulse response...... is not calculated by FIELD II. This work investigates the usability of combining a one-dimensional multilayer transducer modeling principle with the FIELD II software. Multilayer here refers to a transducer composed of several material layers. Measurements of pressure and current from Pz27 piezoceramic disks...... as well as pressure and intensity measurements in front of a 128 element commercial convex medical transducer are compared to the simulations. Results show that the models can predict the pressure from the piezoceramic disks with a root mean square (rms) error of 11.2% to 36.2% with a 2 dB amplitude...

  19. Family of Quantum Sources for Improving Near Field Accuracy in Transducer Modeling by the Distributed Point Source Method

    Directory of Open Access Journals (Sweden)

    Dominique Placko

    2016-10-01

    Full Text Available The distributed point source method, or DPSM, developed in the last decade has been used for solving various engineering problems—such as elastic and electromagnetic wave propagation, electrostatic, and fluid flow problems. Based on a semi-analytical formulation, the DPSM solution is generally built by superimposing the point source solutions or Green’s functions. However, the DPSM solution can be also obtained by superimposing elemental solutions of volume sources having some source density called the equivalent source density (ESD. In earlier works mostly point sources were used. In this paper the DPSM formulation is modified to introduce a new kind of ESD, replacing the classical single point source by a family of point sources that are referred to as quantum sources. The proposed formulation with these quantum sources do not change the dimension of the global matrix to be inverted to solve the problem when compared with the classical point source-based DPSM formulation. To assess the performance of this new formulation, the ultrasonic field generated by a circular planer transducer was compared with the classical DPSM formulation and analytical solution. The results show a significant improvement in the near field computation.

  20. HerMES: Point source catalogues from Herschel-SPIRE observations II

    CERN Document Server

    Wang, L; Clarke, C; Bock, J; Buat, V; Conley, A; Farrah, D; Heinis, S; Magdis, G; Marchetti, L; Marsden, G; Norberg, P; Oliver, S J; Roehlly, Y; Roseboom, I G; Schulz, B; Smith, A J; Vaccari, M; Zemcov, M

    2013-01-01

    The Herschel Multi-tiered Extragalactic Survey (HerMES) is the largest Guaranteed Time Key Programme on the Herschel Space Observatory. With a wedding cake survey strategy, it consists of nested fields with varying depth and area totalling ~380 deg^2. In this paper, we present deep point source catalogues extracted from Herschel-SPIRE observations of all HerMES fields, except for the later addition of the 270 deg^2 HeLMS field. These catalogues constitute the second Data Release (DR2) made in October 2013. A subset of these catalogues, which consists of bright sources extracted from Herschel-SPIRE observations completed by May 1, 2010 (covering ~ 74 deg^2) were released earlier in the first extensive Data Release (DR1) in March 2012. Two different methods are used to generate the point source catalogues, the SUSSEXtractor (SXT) point source extractor used in two earlier data releases (EDR and EDR2) and a new source detection and photometry method. The latter combines an iterative source detection algorithm, S...

  1. Adsorption Capacity of Kaolinite for Copper (II) under Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    DONG Wei

    2004-01-01

    The adsorption of Cu2+ on kaolinite under magnetic field was studied at 25℃.The magnetic effects were investigated by designing the variation of exposure time,magnetic flux density and the method of magnetic exposure.The results from these study show that the magnetic treatment significantly enhance the fraction of adsorption of Cu2+,the adsorption of Cu2+ by kaolinite increases with the increase of pH value from 2 to 6.Both the magnetic exposure time and the magnetic flux density promote the fraction of adsorption Cu2+ on kaolinite.

  2. Test of the rem-counter WENDI-II from Eberline in different energy-dispersed neutron fields

    Energy Technology Data Exchange (ETDEWEB)

    Gutermuth, F.; Radon, T.; Fehrenbacher, G.; Siekmann, R.

    2004-03-01

    The neutron rem-counter WENDI-II from Eberline was tested in high-energy particle accelerator produced neutron fields. A radioactive {sup 241}Am-Be({alpha}n) source was used as a reference. The experimentally determined responses are compared to Monte-Carlo simulations of the response function done by R. H. Olsher et al. (2000). The energy spectra of the accelerator produced neutron fields were determined employing Monte-Carlo simulations, too. According to the simulations done by C. Birattari et al. (1998) and in this work these neutron fields exhibit large contributions to the ambient dose equivalent resulting from neutrons with kinetic energy of more than 20 MeV up to a few 100 MeV. The WENDI-II detector proved to show a response of approximately 3.10{sup 9} pulses per Sievert ambient dose equivalent. Considering the experimental and statistical uncertainties the results are consistent with the assumption that the dose response of the WENDI-II reproduces quite accurately the function for the ambient dose equivalent of the ICRP 74.

  3. Zeeman-Doppler Imaging of II Peg - The magnetic field restructuring from 2004 to 2007

    CERN Document Server

    Carroll, T A; Strassmeier, K G; Ilyin, I; Tuominen, I

    2009-01-01

    We present Zeeman-Doppler images of the active K2 star II Peg for the years 2004 and 2007. The surface magnetic field was reconstructed with our new ZDI code "iMap" which provides a full polarized radiative transfer driven inversion to simultaneously reconstruct the surface temperature and magnetic vector field distribution. II Peg shows a remarkable large scale magnetic field structure for both years. The magnetic field is predominantly located at high latitudes and is arranged in active longitudes. A dramatic evolution in the magnetic field structure is visible for the two years, where a dominant and largely unipolar field in 2004 has developed into two distinct and large scale bipolar structures in 2007.

  4. THE INTERSTELLAR MAGNETIC FIELD CLOSE TO THE SUN. II

    Energy Technology Data Exchange (ETDEWEB)

    Frisch, P. C. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Andersson, B-G [SOFIA Science Center, Universities Space Research Association, NASA Ames Research Center, M.S. N232-12 Moffett Field, CA 94035 (United States); Berdyugin, A.; Piirola, V. [Finnish Centre for Astronomy with ESO, University of Turku (Finland); DeMajistre, R. [The Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States); Funsten, H. O. [Los Alamos National Laboratory, Los Alamos, NM (United States); Magalhaes, A. M.; Seriacopi, D. B. [Inst. de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo (Brazil); McComas, D. J. [Southwest Research Institute, San Antonio, TX (United States); Schwadron, N. A. [Space Science Center, University of New Hampshire, Durham, NH (United States); Slavin, J. D. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Wiktorowicz, S. J. [Department of Astronomy, University of California at Santa Cruz, Santa Cruz, CA (United States)

    2012-12-01

    The magnetic field in the local interstellar medium (ISM) provides a key indicator of the galactic environment of the Sun and influences the shape of the heliosphere. We have studied the interstellar magnetic field (ISMF) in the solar vicinity using polarized starlight for stars within 40 pc of the Sun and 90 Degree-Sign of the heliosphere nose. In Frisch et al. (Paper I), we developed a method for determining the local ISMF direction by finding the best match to a group of interstellar polarization position angles obtained toward nearby stars, based on the assumption that the polarization is parallel to the ISMF. In this paper, we extend the analysis by utilizing weighted fits to the position angles and by including new observations acquired for this study. We find that the local ISMF is pointed toward the galactic coordinates l, b =47 Degree-Sign {+-} 20 Degree-Sign , 25 Degree-Sign {+-} 20 Degree-Sign . This direction is close to the direction of the ISMF that shapes the heliosphere, l, b =33 Degree-Sign {+-} 4 Degree-Sign , 55 Degree-Sign {+-} 4 Degree-Sign , as traced by the center of the 'Ribbon' of energetic neutral atoms discovered by the Interstellar Boundary Explorer (IBEX) mission. Both the magnetic field direction and the kinematics of the local ISM are consistent with a scenario where the local ISM is a fragment of the Loop I superbubble. A nearby ordered component of the local ISMF has been identified in the region l Almost-Equal-To 0 Degree-Sign {yields} 80 Degree-Sign and b Almost-Equal-To 0 Degree-Sign {yields} 30 Degree-Sign , where PlanetPol data show a distance-dependent increase of polarization strength. The ordered component extends to within 8 pc of the Sun and implies a weak curvature in the nearby ISMF of {approx}0.{sup 0}25 pc{sup -1}. This conclusion is conditioned on the small sample of stars available for defining this rotation. Variations from the ordered component suggest a turbulent component of {approx}23 Degree-Sign . The

  5. Localization from near-source quasi-static electromagnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Mosher, J.C.

    1993-09-01

    A wide range of research has been published on the problem of estimating the parameters of electromagnetic and acoustical sources from measurements of signals measured at an array of sensors. In the quasi-static electromagnetic cases examined here, the signal variation from a point source is relatively slow with respect to the signal propagation and the spacing of the array of sensors. As such, the location of the point sources can only be determined from the spatial diversity of the received signal across the array. The inverse source localization problem is complicated by unknown model order and strong local minima. The nonlinear optimization problem is posed for solving for the parameters of the quasi-static source model. The transient nature of the sources can be exploited to allow subspace approaches to separate out the signal portion of the spatial correlation matrix. Decomposition techniques are examined for improved processing, and an adaptation of MUtiple SIgnal Characterization (MUSIC) is presented for solving the source localization problem. Recent results on calculating the Cramer-Rao error lower bounds are extended to the multidimensional problem here. This thesis focuses on the problem of source localization in magnetoencephalography (MEG), with a secondary application to thunderstorm source localization. Comparisons are also made between MEG and its electrical equivalent, electroencephalography (EEG). The error lower bounds are examined in detail for several MEG and EEG configurations, as well as localizing thunderstorm cells over Cape Canaveral and Kennedy Space Center. Time-eigenspectrum is introduced as a parsing technique for improving the performance of the optimization problem.

  6. Electromagnetic induction by finite wavenumber source fields in 2-D lateral heterogeneities - The transverse electric mode

    Science.gov (United States)

    Hermance, J. F.

    1984-01-01

    Electromagnetic induction in a laterally homogeneous earth is analyzed in terms of a source field with finite dimensions. Attention is focused on a time-varying two-dimensional current source directed parallel to the strike of a two-dimensional anomalous structure within the earth, i.e., the E-parallel mode. The spatially harmonic source field is expressed as discontinuities in the magnetic (or electric) field of the current in the source. The model is applied to describing the magnetic gradients across megatectonic features, and may be used to predict the magnetic fields encountered by a satellite orbiting above the ionosphere.

  7. Turbulent Convection in Stellar Interiors. II. The Velocity Field

    CERN Document Server

    Arnett, David; Young, P A

    2008-01-01

    We analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of the simulations (we relate temperature and density fluctuations via coefficients); the procedure (CABS, Convection Algorithms Based on Simulations) is terrestrially testable and is amenable to systematic improvement. We develop a turbulent kinetic energy equation which contains both nonlocal and time dependent terms, and is appropriate if the convective transit time is shorter than the evolutionary time scale. The interpretation of mixing-length theory (MLT) as generally used in astrophysics is incorrect; MLT forces the mixing length to be an imposed constant. Direct tests show that the damping associated with the flow is that suggested by Kolmogorov. The eddy size is approximately the depth of the convection zone, and this dissipation length corresponds to the "mixing length...

  8. Mini-D{sub 2} a source for ultracold neutrons at FRM-II

    Energy Technology Data Exchange (ETDEWEB)

    Altarev, I.; Hartmann, F.J.; Paul, S.; Schott, W.; Trinks, U.; Gobrecht, K.; Gutsmiedl, E. [Technische Universitaet Muenchen, Garching (Germany); Scheuer, A. [TUEV Rheinland, Koeln (Germany)

    2001-03-01

    The new Munich high-flux reactor FRM-II offers the possibility to install a unique source for ultracold neutrons (UCN), the Mini-D{sub 2} UCN source, with a small volume of solid deuterium at a temperature of 5 K as converter, exposed to the cold neutron flux. This new source, being dedicated for storage experiments, is designed to be much superior to any existing UCN facility. In the pulsed operation mode the Mini-D{sub 2} source is expected to provide UCN densities up to 10{sup 4} n/cm{sup 3}. This density is orders of magnitude larger than that from the best existing source at Institut Laue Langevin (ILL) in Grenoble ({approx}50 n/cm{sup 3} at the exit of the neutron turbine). The large gain factor will enable new precision measurements of elementary properties of the free neutron, especially the electric dipole moment, the lifetime, and the angular correlation coefficients of the decay. These quantities are of fundamental interest in particle physics. Operated in the continuous mode, the UCN source will provide an UCN flux density of up to 5{center_dot}10{sup 5} n/cm{sup 2}s at the exit, to be compared with {approx}3{center_dot}10{sup 4} n/cm{sup 2}s at ILL. This improved UCN-flux offers new possibilities for traditional studies with UCN. (author)

  9. XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources

    CERN Document Server

    Haakonsen, Christian Bernt; 10.1088/0067-0049/184/1/138

    2009-01-01

    The 18806 ROSAT All Sky Survey Bright Source Catalog (RASS/BSC) X-ray sources are quantitatively cross-associated with near-infrared (NIR) sources from the Two Micron All Sky Survey Point Source Catalog (2MASS/PSC). An association catalog is presented, listing the most likely counterpart for each RASS/BSC source, the probability Pid that the NIR source and X-ray source are uniquely associated, and the probability Pnoid that none of the 2MASS/PSC sources are associated with the X-ray source. The catalog includes 3853 high quality (Pid>0.98) X-ray--NIR matches, 2280 medium quality (0.98>Pid>0.9) matches, and 4153 low quality (0.9>Pid>0.5) matches. Of the high quality matches, 1418 are associations that are not listed in the SIMBAD database, and for which no high quality match with a USNO-A2 optical source was presented for the RASS/BSC source in previous work. The present work offers a significant number of new associations with RASS/BSC objects that will require optical/NIR spectroscopy for classification. For...

  10. Integral field spectroscopy of supernova explosion sites: constraining mass and metallicity of the progenitors -- II. Type II-P and II-L supernovae

    CERN Document Server

    Kuncarayakti, Hanindyo; Aldering, Greg; Arimoto, Nobuo; Maeda, Keiichi; Morokuma, Tomoki; Pereira, Rui; Usuda, Tomonori; Hashiba, Yasuhito

    2013-01-01

    Thirteen explosion sites of type II-P and II-L supernovae in nearby galaxies have been observed using integral field spectroscopy, enabling both spatial and spectral study of the explosion sites. We used the properties of the parent stellar population of the coeval supernova progenitor star to derive its metallicity and initial mass (c.f. Paper I). The spectrum of the parent stellar population yields the estimates of metallicity via strong-line method, and age via comparison with simple stellar population (SSP) models. These metallicity and age parameters are adopted for the progenitor star. Age, or lifetime of the star, was used to derive initial (ZAMS) mass of the star by comparing with stellar evolution models. With this technique, we were able to determine metallicity and initial mass of the SN progenitors in our sample. Our result indicates that some type-II supernova progenitors may have been stars with mass comparable to SN Ib/c progenitors.

  11. A Deep XMM-Newton Survey of M33: Point Source Catalog, Source Detection and Characterization of Overlapping Fields

    CERN Document Server

    Williams, Benjamin F; Haberl, Frank; Garofali, Kristen; Blair, William P; Gaetz, Terrance J; Kuntz, K D; Long, Knox S; Pannuti, Thomas G; Pietsch, Wolfgang; Plucinsky, Paul P; Winkler, P Frank

    2015-01-01

    We have obtained a deep 8-field XMM-Newton mosaic of M33 covering the galaxy out to the D$_{25}$ isophote and beyond to a limiting 0.2--4.5 keV unabsorbed flux of 5$\\times$10$^{-16}$ erg cm$^{-2}$ s$^{-1}$ (L${>}$4$\\times$10$^{34}$ erg s$^{-1}$ at the distance of M33). These data allow complete coverage of the galaxy with high sensitivity to soft sources such as diffuse hot gas and supernova remnants. Here we describe the methods we used to identify and characterize 1296 point sources in the 8 fields. We compare our resulting source catalog to the literature, note variable sources, construct hardness ratios, classify soft sources, analyze the source density profile, and measure the X-ray luminosity function. As a result of the large effective area of XMM-Newton below 1 keV, the survey contains many new soft X-ray sources. The radial source density profile and X-ray luminosity function for the sources suggests that only $\\sim$15% of the 391 bright sources with L${>}$3.6$\\times$10$^{35}$ erg s$^{-1}$ are likely...

  12. Teachers' Sources of Knowledge for Field Trip Practices

    Science.gov (United States)

    Rebar, Bryan M.

    2012-01-01

    Teachers draw from many personal and professional experiences when organising and leading field trips. In order to identify the influences on teachers' field trip practices, I used surveys, interviews, artifacts and observations gathered from teachers who led trips to an aquarium. Findings clarified the types of influence and the impact that these…

  13. Nonlinear Electromagnetic Fields As a Source of Universe Acceleration

    CERN Document Server

    Kruglov, S I

    2016-01-01

    A model of nonlinear electromagnetic fields with a dimensional parameter $\\beta$ is proposed. From PVLAS experiment the bound on the parameter $\\beta$ was obtained. Electromagnetic fields are coupled with the gravitation field and we show that the universe accelerates due to nonlinear electromagnetic fields. The magnetic universe is considered and the stochastic magnetic field is a background. After inflation the universe decelerates and approaches to the radiation era. The range of the scale factor, when the causality of the model and a classical stability take place, was obtained. The spectral index, the tensor-to-scalar ratio, and the running of the spectral index were estimated which are in approximate agreement with the PLANCK, WMAP, and BICEP2 data.

  14. Diagnostics on the source properties of type II radio burst with spectral bumps

    CERN Document Server

    Feng, S W; Kong, X L; Li, G; Song, H Q; Feng, X S; Guo, F

    2013-01-01

    In recent studies (Feng et al., 2012; Kong et al., 2012), we proposed that source properties of type II radio bursts can be inferred through a causal relationship between the special shape of the type II dynamic spectrum (e.g., bump or break) and simultaneous extreme ultraviolet (EUV)/white light imaging observations (e.g., CME-shock crossing streamer structures). As a further extension of these studies, in this paper we examine the CME event dated on December 31 2007 associated with a multiple type II radio burst. We identify the presence of two spectral bump features on the observed dynamic spectrum. By combining observational analyses of the radio spectral observations and the EUV-white light imaging data, we conclude that the two spectral bumps are resulted from CME-shock propagating across dense streamers on the southern and northern sides of the CME, respectively. It is inferred that the corresponding two type II emissions originate separately from the two CME-shock flanks where the shock geometries are...

  15. An Equivalent Source Method for Modelling the Global Lithospheric Magnetic Field

    DEFF Research Database (Denmark)

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

    2014-01-01

    are also employed to minimize the influence of the ionospheric field. The model for the remaining lithospheric magnetic field consists of magnetic point sources (monopoles) arranged in an icosahedron grid. The corresponding source values are estimated using an iteratively reweighted least squares algorithm......We present a new technique for modelling the global lithospheric magnetic field at Earth's surface based on the estimation of equivalent potential field sources. As a demonstration we show an application to magnetic field measurements made by the CHAMP satellite during the period 2009-2010 when...

  16. Calabi-Yau Manifolds Over Finite Fields, II

    CERN Document Server

    Candelas, Philip; Rodríguez-Villegas, F; Candelas, Philip; Ossa, Xenia de la; Rodriguez-Villegas, Fernando

    2004-01-01

    We study zeta-functions for a one parameter family of quintic threefolds defined over finite fields and for their mirror manifolds and comment on their structure. The zeta-function for the quintic family involves factors that correspond to a certain pair of genus 4 Riemann curves. The appearance of these factors is intriguing since we have been unable to `see' these curves in the geometry of the quintic. Having these zeta-functions to hand we are led to comment on their form in the light of mirror symmetry. That some residue of mirror symmetry survives into the zeta-functions is suggested by an application of the Weil conjectures to Calabi-Yau threefolds: the zeta-functions are rational functions and the degrees of the numerators and denominators are exchanged between the zeta-functions for the manifold and its mirror. It is clear nevertheless that the zeta-function, as classically defined, makes an essential distinction between Kahler parameters and the coefficients of the defining polynomial. It is an inter...

  17. Homogeneous Magnetic Field Source For Attenuated Total Reflection

    Directory of Open Access Journals (Sweden)

    Lesňák Michal

    2014-07-01

    Full Text Available The paper is focused on the study of two-dimensional magnetic field distribution used for an analysis of samples containing magnetically active films by means of the Attenuated Total Reflection (ATR method. The design of a proposed electromagnet and the magnetic field model computation are presented together with the results obtained from magnetic field distribution measurement. The ATR method can provide information about a thin film thickness, refractive index, and attenuation in addition to the perfunctory coupling of an optical wave into and off a waveguide [1, 2]. The prism coupling conditions are determined for magnetic structures with induced anisotropy.

  18. A procedure to estimate the electric field induced in human body exposed to unknown magnetic sources.

    Science.gov (United States)

    Wang, Wencui; Bottauscio, Oriano; Chiampi, Mario; Giordano, Domenico; Zilberti, Luca

    2013-04-01

    The paper proposes and discusses a boundary element procedure able to predict the distribution of the electric field induced in a human body exposed to a low-frequency magnetic field produced by unknown sources. As a first step, the magnetic field on the body surface is reconstructed starting from the magnetic field values detected on a closed surface enclosing the sources. Then, the solution of a boundary value problem provides the electric field distribution inside the human model. The procedure is tested and validated by considering different non-uniform magnetic field distributions generated by a Helmholtz coil system as well as different locations of the human model.

  19. An Equivalent Source Method for Modelling the Global Lithospheric Magnetic Field

    DEFF Research Database (Denmark)

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

    2015-01-01

    are also employed to minimize the influence of the ionospheric field. The model for the remaining lithospheric magnetic field consists of magnetic equivalent potential field sources (monopoles) arranged in an icosahedron grid at a depth of 100 km belowthe surface. The corresponding model parameters......We present a new technique for modelling the global lithospheric magnetic field at Earth’s surface based on the estimation of equivalent potential field sources. As a demonstration we show an application to magnetic field measurements made by the CHAMP satellite during the period 2009–2010 when...

  20. A multi-source precipitation approach to fill gaps over a radar precipitation field

    Science.gov (United States)

    Tesfagiorgis, K. B.; Mahani, S. E.; Khanbilvardi, R.

    2012-12-01

    Satellite Precipitation Estimates (SPEs) may be the only available source of information for operational hydrologic and flash flood prediction due to spatial limitations of radar and gauge products. The present work develops an approach to seamlessly blend satellite, radar, climatological and gauge precipitation products to fill gaps over ground-based radar precipitation fields. To mix different precipitation products, the bias of any of the products relative to each other should be removed. For bias correction, the study used an ensemble-based method which aims to estimate spatially varying multiplicative biases in SPEs using a radar rainfall product. Bias factors were calculated for a randomly selected sample of rainy pixels in the study area. Spatial fields of estimated bias were generated taking into account spatial variation and random errors in the sampled values. A weighted Successive Correction Method (SCM) is proposed to make the merging between error corrected satellite and radar rainfall estimates. In addition to SCM, we use a Bayesian spatial method for merging the gap free radar with rain gauges, climatological rainfall sources and SPEs. We demonstrate the method using SPE Hydro-Estimator (HE), radar- based Stage-II, a climatological product PRISM and rain gauge dataset for several rain events from 2006 to 2008 over three different geographical locations of the United States. Results show that: the SCM method in combination with the Bayesian spatial model produced a precipitation product in good agreement with independent measurements. The study implies that using the available radar pixels surrounding the gap area, rain gauge, PRISM and satellite products, a radar like product is achievable over radar gap areas that benefits the scientific community.

  1. Probabilistic Tsunami Hazard in the NE Atlantic from Near- and Far-field Tectonic Sources

    Science.gov (United States)

    Omira, R.; Baptista, M.; Matias, L.; Carrilho, F.; Miranda, J. M.

    2012-12-01

    A comprehensive assessment of the hazard posed by tsunamis must include an evaluation of the possible tsunami impact from near- and far-field sources as well as its likelihood of occurrence. In the NE Atlantic region, tsunami hazard assessment has been mainly performed through deterministic approaches considering regional most credible earthquake scenarios. This work focuses on the probabilistic approach for tsunami hazard assessment in the NE Atlantic region. The advantage of such approach consists of yielding information on the likelihood of tsunami impact in addition to the other components of hazard assessment (wave heights, inundation, run-up…etc). Probabilistic tsunami hazard assessment approach, used here, integrates tsunami waveform and inundation modeling with probabilistic seismic hazard assessment methods. This approach consists of various steps: i) identification of tsunami sources and assessment of their annual rates of recurrence; ii) Numerical simulations of near-shore waveform and flooding; iii) Evaluation of the probability exceedance for wave heights and inundations for a given period of time; vi) Derivation of tsunami hazard curves. Both near- and far-field seismic sources able to trigger tsunamis that reach/affect the NE Atlantic coasts are considered in order to generate a set of credible scenarios for the region. This database incorporates various magnitude ranges of possible earthquakes generated at the potential tsunamigenic zones from the Gulf of Cadiz to the Caribbean. The annual recurrence rate of each magnitude range is derived through the Bayesian method that incorporates seismic information from historical catalog and instrumental periods for the Gulf of Cadiz, while we will use only instrumental information for the Caribbean source area. A numerical code, solving shallow water equations in their linear and non linear forms, is then employed to simulate the tsunami propagation and flooding resulting from the occurrence of the

  2. Gamma-Ray Bursts as Sources of Strong Magnetic Fields

    CERN Document Server

    Granot, Jonathan; Bromberg, Omer; Racusin, Judith L; Daigne, Frédéric

    2015-01-01

    Gamma-Ray Bursts (GRBs) are the strongest explosions in the Universe, which due to their extreme character likely involve some of the strongest magnetic fields in nature. This review discusses the possible roles of magnetic fields in GRBs, from their central engines, through the launching, acceleration and collimation of their ultra-relativistic jets, to the dissipation and particle acceleration that power their $\\gamma$-ray emission, and the powerful blast wave they drive into the surrounding medium that generates their long-lived afterglow emission. An emphasis is put on particular areas in which there have been interesting developments in recent years.

  3. A Novel Algorithm Based on 3D-MUSIC Algorithm for Localizing Near-Field Source

    Institute of Scientific and Technical Information of China (English)

    SHAN Zhi-yong; ZHOU Xi-lang; PEN Gen-jiang

    2005-01-01

    A novel 3-D MUSIC algorithm based on the classical 3D-MUSIC algorithm for the location of near-field source was presented. Under the far-field assumption of actual near-field, two algebraic relations of the location parameters between the actual near-field sources and the far-field ones were derived. With Fourier transformation and polynomial-root methods, the elevation and the azimuth of the far-field were obtained, the tracking paths can be developed, and the location parameters of the near-field source can be determined, then the more accurate results can be estimated using an optimization method. The computer simulation results p rove that the algorithm for the location of the near-fields is more accurate, effective and suitable for real-time applications.

  4. Wave field synthesis of moving virtual sound sources with complex radiation properties.

    Science.gov (United States)

    Ahrens, Jens; Spors, Sascha

    2011-11-01

    An approach to the synthesis of moving virtual sound sources with complex radiation properties in wave field synthesis is presented. The approach exploits the fact that any stationary sound source of finite spatial extent radiates spherical waves at sufficient distance. The angular dependency of the radiation properties of the source under consideration is reflected by the amplitude and phase distribution on the spherical wave fronts. The sound field emitted by a uniformly moving monopole source is derived and the far-field radiation properties of the complex virtual source under consideration are incorporated in order to derive a closed-form expression for the loudspeaker driving signal. The results are illustrated via numerical simulations of the synthesis of the sound field of a sample moving complex virtual source.

  5. Six-dimensional Methods for Four-dimensional Conformal Field Theories II: Irreducible Fields

    CERN Document Server

    Weinberg, Steven

    2012-01-01

    This note supplements an earlier paper on conformal field theories. There it was shown how to construct tensor, spinor, and spinor-tensor primary fields in four dimensions from their counterparts in six dimensions, where conformal transformations act simply as SO(4,2) Lorentz transformations. Here we show how to constrain fields in six dimensions so that the corresponding primary fields in four dimensions transform according to irreducible representations of the four-dimensional Lorentz group, even when the irreducibility conditions on these representations involve the four-component Levi-Civita tensor $\\epsilon_{\\mu\

  6. A Fast Field Scheme for the Parametric Sound Radiation from Rectangular Aperture Source

    Institute of Scientific and Technical Information of China (English)

    杨军; 沙侃; 颜允圣; 田静

    2004-01-01

    A virtual complex source approach has been developed to calculate numerically the ultrasound field generated by a rectangular planar source with high efficiency. The sound field can be treated as the resultant sound pressure from a set of complex virtual sources located at a complex distance, and then by exploiting the integrability of Gaussian function, a substantial analytical reduction to single integral is derived for the second-order field of the sum-, difference-frequency and second harmonic components. The validity of this fast field scheme is confirmed by comparison of numerical results and the experimental data published previously.

  7. Observations of the Hubble Deep Field with the Infrared Space Observatory .2. Source detection and photometry

    DEFF Research Database (Denmark)

    Goldschmidt, P.; Oliver, S.J.; Serjeant, S.B.G.

    1997-01-01

    We present positions and fluxes of point sources found in the Infrared Space Observatory (ISO) images of the Hubble Deep Field (HDF) at 6.7 and 15 mu m. We have constructed algorithmically selected 'complete' flux-limited samples of 19 sources in the 15-mu m image, and seven sources in the 6.7-mu m...

  8. Manipulating carbon nanotubes Towards the application as novel field emission sources

    NARCIS (Netherlands)

    Heeres, Erwin Cornelis

    2014-01-01

    This thesis is about the research performed on novel field emission sources. Having a better electron source can reduce the time needed to obtain an electron microscope image and enable studying processes at a higher resolution. We chose to fabricate electron sources by means of mounting

  9. Observations of the Hubble Deep Field with the Infrared Space Observatory .2. Source detection and photometry

    DEFF Research Database (Denmark)

    Goldschmidt, P.; Oliver, S.J.; Serjeant, S.B.G.;

    1997-01-01

    We present positions and fluxes of point sources found in the Infrared Space Observatory (ISO) images of the Hubble Deep Field (HDF) at 6.7 and 15 mu m. We have constructed algorithmically selected 'complete' flux-limited samples of 19 sources in the 15-mu m image, and seven sources in the 6.7-mu m...

  10. SOLUTION OF FIELD TASKS OF AN ELECTRICAL ENGINEERING WITH THE HELP OF SECONDARY SOURCES OF A FIELD AND FOURIER SERIES

    Directory of Open Access Journals (Sweden)

    Popov B. K.

    2013-11-01

    Full Text Available For a field task, we have shown the analytical solution of the control example by means of which the condi-tions of the correct application of a method of second-ary sources of a field. The numerical decision in the form of Fourier series of the same task, but with use of the method of secondary sources is found. The method of the registration of heterogeneity of the environment which enters secondary sources the way that bring together analytical and numerical solutions is offered

  11. On guided versus deflected fields in controlled-source electromagnetics

    Science.gov (United States)

    Swidinsky, Andrei

    2015-06-01

    The detection of electrically resistive targets in applied geophysics is of interest to the hydrocarbon, mining and geotechnical industries. Elongated thin resistive bodies have been extensively studied in the context of offshore hydrocarbon exploration. Such targets guide electromagnetic fields in a process which superficially resembles seismic refraction. On the other hand, compact resistive bodies deflect current in a process which has more similarities to diffraction and scattering. The response of a real geological structure is a non-trivial combination of these elements-guiding along the target and deflection around its edges. In this note the electromagnetic responses of two end-member models are compared: a resistive layer, which guides the electromagnetic signal, and a resistive cylinder, which deflects the fields. Results show that the response of a finite resistive target tends to saturate at a much lower resistivity than a resistive layer, under identical survey configurations. Furthermore, while the guided electromagnetic fields generated by a buried resistive layer contain both anomalous horizontal and vertical components, the process of electromagnetic deflection from a buried resistive cylinder creates mainly anomalous vertical fields. Finally, the transmitter orientation with respect to the position of a finite body is an important survey parameter: when the distance to the target is much less than the host skin depth, a transmitter pointing towards the resistive cylinder will produce a stronger signal than a transmitter oriented azimuthally with respect to the cylinder surface. The opposite situation is observed when the distance to the target is greater than the host skin depth.

  12. History of Reading: Status and Sources of a Growing Field.

    Science.gov (United States)

    Cranney, A. Garr; Miller, Janet

    Recent developments in the field of reading indicate that a number of reading educators recognize the importance of studying the history of reading as a part of the knowledge base of reading education. A questionnaire was mailed to all coordinators of United States and Canadian programs listed in the International Reading Association's…

  13. Directivity of Spherical Polyhedron Sound Source Used in Near-Field HRTF Measurements

    Institute of Scientific and Technical Information of China (English)

    YU Guang-Zheng; XIE Bo-Sun; RAO Dan

    2010-01-01

    @@ The omnidirectional character is one of important requirements for the sound source used in near-field headrelated transfer function(HRTF)measurements.Based on the analysis on the radiation sound pressure and directivity character of various spherical polyhedron sound sources,a spherical dodecahedral sound source with radius of 0.035 m is proposed and manufactured.Theoretical and measured results indicate that the sound source is approximately omnidirectional below the frequency of 8 kHz.In addition,the sound source has reasonable magnitude response from 350Hz to 20kHz and linear phase characteristics.Therefore.it is suitahle for the near-field HRTF measurements.

  14. Blank field submm sources, failed stars, and the dark matter

    CERN Document Server

    Lawrence, A

    2000-01-01

    I discuss the possibility that a significant fraction (possibly a third) of the faint SCUBA sources are not in fact high redshift galaxies, but actually local cold dark dusty gas clouds emitting only in the submm, with a temperature around 7K. I show that the observational constraints on such a population - dynamical limits on missing matter, the FIR-mm background, and the absence of gross high-latitude extinction features - constrains the mass of such objects to be in the range 0.1 - 10 Jupiter masses. The characteristics deduced are closely similar to those of the objects proposed by Walker and Wardle (1998) to explain halo dark matter. However, such objects, if they explain a large fraction of the SCUBA sources, cannot extend through the halo without greatly exceeding the FIR-mm background. Instead, I deduce the characteristic distance of the SCUBA sources to be around 100 pc, consistent with being drawn from a disk population with a scale height of few hundred parsecs. Regardless of the dark matter proble...

  15. Uncertainties in field-line tracing in the magnetosphere. Part II: the complete internal geomagnetic field

    Directory of Open Access Journals (Sweden)

    K. S. C. Freeman

    Full Text Available The discussion in the preceding paper is restricted to the uncertainties in magnetic-field-line tracing in the magnetosphere resulting from published standard errors in the spherical harmonic coefficients that define the axisymmetric part of the internal geomagnetic field (i.e. gn0 ± δgn0. Numerical estimates of these uncertainties based on an analytic equation for axisymmetric field lines are in excellent agreement with independent computational estimates based on stepwise numerical integration along magnetic field lines. This comparison confirms the accuracy of the computer program used in the present paper to estimate the uncertainties in magnetic-field-line tracing that arise from published standard errors in the full set of spherical harmonic coefficients, which define the complete (non-axisymmetric internal geomagnetic field (i.e. gnm ± δgnm and hnm ± δhnm. An algorithm is formulated that greatly reduces the computing time required to estimate these uncertainties in magnetic-field-line tracing. The validity of this algorithm is checked numerically for both the axisymmetric part of the internal geomagnetic field in the general case (1 ≤ n ≤ 10 and the complete internal geomagnetic field in a restrictive case (0 ≤ m ≤ n, 1 ≤ n ≤ 3. On this basis it is assumed that the algorithm can be used with confidence in those cases for which the computing time would otherwise be prohibitively long. For the complete internal geomagnetic field, the maximum characteristic uncertainty in the geocentric distance of a field line that crosses the geomagnetic equator at a nominal dipolar distance of 2 RE is typically 100 km. The corresponding characteristic uncertainty for a field line that crosses the geomagnetic equator at a nominal dipolar distance of 6 RE is typically 500 km. Histograms and scatter plots showing the characteristic uncertainties associated with magnetic-field-line tracing in the magnetosphere are presented for a range of

  16. A carbon nanotube field emission multipixel x-ray array source for microradiotherapy application

    OpenAIRE

    Wang, Sigen; Calderon, Xiomara; Peng, Rui; Schreiber, Eric C.; Zhou, Otto; Chang, Sha

    2011-01-01

    The authors report a carbon nanotube (CNT) field emission multipixel x-ray array source for microradiotherapy for cancer research. The developed multipixel x-ray array source has 50 individually controllable pixels and it has several distinct advantages over other irradiation source including high-temporal resolution (millisecond level), the ability to electronically shape the form, and intensity distribution of the radiation fields. The x-ray array was generated by a CNT cathode array (5×10)...

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

    DEFF Research Database (Denmark)

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

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

  18. Cosmological evolution of the Fanaroff-Riley type II source population

    CERN Document Server

    Wang, Y

    2008-01-01

    By combining a model for the evolution of the radio luminosity of an individual source with the radio luminosity function, we perform a multi-dimensional Monte-Carlo simulation to investigate the cosmological evolution of the Fanaroff-Riley Class II radio galaxy population by generating large artificial samples. The properties of FRII sources are required to evolve with redshift in the artificial samples to fit the observations. Either the maximum jet age or the maximum density of the jet environment or both evolve with redshift. We also study the distribution of FRII source properties as a function of redshift. From currently available data we can not constrain the shape of the distribution of environment density or age, but jet power is found to follow a power-law distribution with an exponent of approximately -2. This power-law slope does not change with redshift out to z=0.6. We also find the distribution of the pressure in the lobes of FRII sources to evolve with redshift up to $z\\sim1.2$.

  19. The universal C*-algebra of the electromagnetic field II. Topological charges and spacelike linear fields

    Science.gov (United States)

    Buchholz, Detlev; Ciolli, Fabio; Ruzzi, Giuseppe; Vasselli, Ezio

    2017-02-01

    Conditions for the appearance of topological charges are studied in the framework of the universal C*-algebra of the electromagnetic field, which is represented in any theory describing electromagnetism. It is shown that non-trivial topological charges, described by pairs of fields localised in certain topologically non-trivial spacelike separated regions, can appear in regular representations of the algebra only if the fields depend non-linearly on the mollifying test functions. On the other hand, examples of regular vacuum representations with non-trivial topological charges are constructed, where the underlying field still satisfies a weakened form of "spacelike linearity". Such representations also appear in the presence of electric currents. The status of topological charges in theories with several types of electromagnetic fields, which appear in the short distance (scaling) limit of asymptotically free non-abelian gauge theories, is also briefly discussed.

  20. Understanding the source: The nitrogen isotope composition of Type II mantle diamonds

    Science.gov (United States)

    Mikhail, Sami; Howell, Dan; Jones, Adrian; Milledge, Judith; Verchovsky, Sasha

    2010-05-01

    Diamonds can be broadly subdivided into 2 groups based on their nitrogen content; type I with > 10ppm nitrogen and type II with growth nitrogen can be incorporated into diamond as a compatible element in a closed system and therefore the N/C ratio in the source can be depleted by Rayleigh fractionation as the first diamonds to crystallise will partition nitrogen atoms into their lattice as a 1:1 substitution for carbon atoms (type I diamonds). However nitrogen may behave as an incompatible element in diamond (and be a compatible element in the metasomatic fluid), this coupled with an open system would lead to the removal of nitrogen by the metasomatic fluids, thus causing the source to progressively become depleted in nitrogen. Continued diamond crystallization in either system will produce diamonds with ever decreasing nitrogen concentrations with time, possibly to the point of them being almost nitrogen free. 2- It is conceivable that type I & II diamonds found in the same deposit and sharing a common paragenesis (eclogitic or peridotitic) may have formed from different metasomatic fluids in separate diamond forming events. The latter has been proposed for samples from the Cullinan mine (South Africa) based on their carbon isotope compositions (3). Both models can be tested using the stable isotope compositions of carbon and nitrogen with the N/C ratio of the diamonds in a given population with varying nitrogen content (from type I to type II). 1.D. G. Pearson, D. Canil, S. B. Shirey, D. H. Heinrich, K. T. Karl, in Treatise on Geochemistry. (Pergamon, Oxford, 2003), pp. 171-275. 2.C. McCammon, Science 293, 813 (August 3, 2001, 2001). 3.A. E. Moore, South African Journal of Geology 112, 23 (March 1, 2009, 2009).

  1. FR II radio galaxies at low frequencies I: morphology, magnetic field strength and energetics

    CERN Document Server

    Harwood, Jeremy J; Intema, Huib T; Stewart, Adam J; Ineson, Judith; Hardcastle, Martin J; Godfrey, Leith; Best, Philip; Brienza, Marisa; Heesen, Volker; Mahony, Elizabeth K; Morganti, Raffaella; Murgia, Matteo; Orrú, Emanuela; Röttgering, Huub; Shulevski, Aleksandar; Wise, Michael W

    2016-01-01

    Due to their steep spectra, low-frequency observations of FR II radio galaxies potentially provide key insights in to the morphology, energetics and spectrum of these powerful radio sources. However, limitations imposed by the previous generation of radio interferometers at metre wavelengths has meant that this region of parameter space remains largely unexplored. In this paper, the first in a series examining FR IIs at low frequencies, we use LOFAR observations between 50 and 160 MHz, along with complementary archival radio and X-ray data, to explore the properties of two FR II sources, 3C452 and 3C223. We find that the morphology of 3C452 is that of a standard FR II rather than of a double-double radio galaxy as had previously been suggested, with no remnant emission being observed beyond the active lobes. We find that the low-frequency integrated spectra of both sources are much steeper than expected based on traditional assumptions and, using synchrotron/inverse-Compton model fitting, show that the total ...

  2. Effect of Sound Source Scattering on Measurement of Near-Field Head-Related Transfer Functions

    Institute of Scientific and Technical Information of China (English)

    YU Guang-Zheng; XIE Bo-Sun; RAO Dan

    2008-01-01

    @@ A simple spherical head and pulsating spherical sound source model are proposed to investigate the effect of multiple scattering between the head and the sound source on near-field head-related transfer function (HRTF) measurement. Multipole expansion method is used to calculate HRTFs of the model, then the relationships among the magnitude error of HRTF with frequency, source direction, source size, and the distance between the head centre and the sound source are analysed. The results show that to ensure the magnitude error of HRTF within 1.0 dB up to 20 kHz, for source distance not less than 0.15m or 0.20 m, the radius of the sound source should not exceed 0.03 m or 0.05 m, respectively. The conclusion suggests an appropriate size of sound source in near-field HRTF measurement.

  3. Magnetic field disorder and Faraday effects on the polarization of extragalactic radio sources

    CERN Document Server

    Lamee, Mehdi; Farnes, Jamie S; Carretti, Ettore; Gaensler, B M; Haverkorn, Marijke; Poppi, Sergio

    2016-01-01

    We present a polarization catalog of 533 extragalactic radio sources with 2.3 GHz total intensity above 420 mJy from the S-band Polarization All Sky Survey, S-PASS, with corresponding 1.4 GHz polarization information from the NRAO VLA Sky Survey, NVSS. We studied selection effects and found that fractional polarization, $\\pi$, of radio objects at both wavelengths depends on the spectral index, source magnetic field disorder, source size and depolarization. The relationship between depolarization, spectrum and size shows that depolarization occurs primarily in the source vicinity. The median $\\pi_{2.3}$ of resolved objects in NVSS is approximately two times larger than that of unresolved sources. Sources with little depolarization are $\\sim2$ times more polarized than both highly depolarized and re-polarized sources. This indicates that intrinsic magnetic field disorder is the dominant mechanism responsible for the observed low fractional polarization of radio sources at high frequencies. We predict that numbe...

  4. VizieR Online Data Catalog: GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)

    Science.gov (United States)

    Spitzer Science, Center

    2009-06-01

    The Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE), is a survey of Galactic Plane central parts made with the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope (SST). It covers approximately 220 square degrees, between galactic longitudes ±65° and ±1° in galactic latitude (up to 4.2° in the central parts). The four IRAC bands are centered at approximately 3.6, 4.5, 5.8 and 8.0μm. The GLIMPSE combines the 3 surveys: * GLIMPSE-I covers the longitude ranges |l|=10--65° and the latitude range |b|Benjamin et al. 2003PASP..115..953B) * GLIMPSE-II covers the longitude range of |l| 5 cut for the band with the two detections. There are also faint and bright flux limits on the Catalog entries. The more complete v2.0 Archive (v2.0_GLMIIA) has less stringent criteria, namely two detections in any bands, those detections having a S/N > 5. The IRAC data were bandmerged with the 2MASS All-Sky Point Source Catalog. See the GLIMPSEII v2.0 Data Products & Data Delivery document for more details. The catalog available from CDS merges the 3 surveys GLIMPSE-I (v2.0), GLIMPSE-II (v2.0), and GLIMPSE-3D; Catalog and Archive records are also merged here. In the regions of overlap between the 3 surveys (e.g. longitude around 10°) preference was given to (1) GLIMPSE-II, as recommended in the GLIMPSE documents of May 2007 (glimpse1_v2.0.pdf) and April 2008 (glimpse2-v2.0.pdf); (2) GLIMPSE-I, and (3) GLIMPSE-3D sources. Sources from different surveys were merged if their position is closer than 0.1arcsec. Documents and a document describing in detail the point source photometry steps, see http://www.astro.wisc.edu/glimpse/docs.html (1 data file).

  5. Clustering, randomness and regularity in cloud fields. I - Theoretical considerations. II - Cumulus cloud fields

    Science.gov (United States)

    Weger, R. C.; Lee, J.; Zhu, Tianri; Welch, R. M.

    1992-01-01

    The current controversy existing in reference to the regularity vs. clustering in cloud fields is examined by means of analysis and simulation studies based upon nearest-neighbor cumulative distribution statistics. It is shown that the Poisson representation of random point processes is superior to pseudorandom-number-generated models and that pseudorandom-number-generated models bias the observed nearest-neighbor statistics towards regularity. Interpretation of this nearest-neighbor statistics is discussed for many cases of superpositions of clustering, randomness, and regularity. A detailed analysis is carried out of cumulus cloud field spatial distributions based upon Landsat, AVHRR, and Skylab data, showing that, when both large and small clouds are included in the cloud field distributions, the cloud field always has a strong clustering signal.

  6. The 1995 revision of the joint US/UK geomagnetic field models. II: Main field

    Science.gov (United States)

    Quinn, J.M.; Coleman, R.J.; Macmillan, S.; Barraclough, D.R.

    1997-01-01

    This paper presents the 1995 main-field revision of the World Magnetic Model (WMM-95). It is based on Project MAGNET high-level (??? 15,000 ft.) vector aeromagnetic survey data collected between 1988 and 1994 and on scalar total intensity data collected by the Polar Orbiting Geomagnetic Survey (POGS) satellite during the period 1991 through 1993. The spherical harmonic model produced from these data describes that portion of the Earth's magnetic field generated internal to the Earth's surface at the 1995.0 Epoch. When combined with the spherical harmonic model of the Earth's secular variation described in paper I, the Earth's main magnetic field is fully characterized between the years 1995 and 2000. Regional magnetic field models for the conterminous United States, Alaska and, Hawaii were generated as by-products of the global modeling process.

  7. Distributional sources for Newman's holomorphic Coulomb field

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Gerald [Center for Signals and Waves, Austin, TX (United States)

    2004-09-10

    Newman (1973 J. Math. Phys. 14 102-3) considered the holomorphic extension E-tilde(z) of the Coulomb field E(x) in R{sup 3}. From an analysis of its multipole expansion, he concluded that the real and imaginary parts E(x+iy){identical_to}Re E-tilde(x+iy), H(x+iy){identical_to}Im E-tilde(x+iy), viewed as functions of x, are the electric and magnetic fields generated by a spinning ring of charge R. This represents the EM part of the Kerr-Newman solution to the Einstein-Maxwell equations (Newman E T and Janis A I 1965 J. Math. Phys. 6 915-7; Newman E T et al 1965 J. Math. Phys. 6 918-9). As already pointed out in Newman and Janis (1965 J. Math. Phys. 6 915-7), this interpretation is somewhat problematic since the fields are double-valued. To make them single-valued, a branch cut must be introduced so that R is replaced by a charged disc D having R as its boundary. In the context of curved spacetime, D becomes a spinning disc of charge and mass representing the singularity of the Kerr-Newman solution. Here we confirm the above interpretation of E and H without resorting to asymptotic expansions, by computing the charge and current densities directly as distributions in R{sup 3} supported in D. This will show that D spins rigidly at the critical rate so that its rim R moves at the speed of light.

  8. Crowd-sourcing Meteorological Data for Student Field Projects

    Science.gov (United States)

    Bullard, J. E.

    2016-12-01

    This paper explains how students can rapidly collect large datasets to characterise wind speed and direction under different meteorological conditions. The tools used include a mobile device (tablet or phone), low cost wind speed/direction meters that are plugged in to the mobile device, and an app with online web support for uploading, collating and georeferencing data. Electronic customised data input forms downloaded to the mobile device are used to ensure students collect data using specified protocols which streamlines data management and reduces the likelihood of data entry errors. A key benefit is the rapid collection and quality control of field data that can be promptly disseminated to students for subsequent analysis.

  9. Selective Monohydrocyanation of Diimine using Potassium Hexacyanoferrate(II)-Benzoyl Chloride Reagent System as a Cyanide Source

    Indian Academy of Sciences (India)

    ZHENG LI; FEI WEN; JINGYA YANG

    2016-12-01

    The selective monohydrocyanation of diimines using potassium hexacyanoferrate(II)-benzoyl chloride reagent system as a cyanide source under catalyst-free condition is described. The advantages of this protocol are the non-toxic, non-volatile and inexpensive cyanide source, high yield, and simple work-up procedure.

  10. LRS Bianchi Type II Massive String Cosmological Models with Magnetic Field in Lyra's Geometry

    Directory of Open Access Journals (Sweden)

    Raj Bali

    2013-01-01

    Full Text Available Bianchi type II massive string cosmological models with magnetic field and time dependent gauge function ( in the frame work of Lyra's geometry are investigated. The magnetic field is in -plane. To get the deterministic solution, we have assumed that the shear ( is proportional to the expansion (. This leads to , where and are metric potentials and is a constant. We find that the models start with a big bang at initial singularity and expansion decreases due to lapse of time. The anisotropy is maintained throughout but the model isotropizes when . The physical and geometrical aspects of the model in the presence and absence of magnetic field are also discussed.

  11. Slender Ca II H fibrils mapping magnetic fields in the low solar chromosphere

    CERN Document Server

    Jafarzadeh, Shahin; Solanki, S K; Wiegelmann, T; Riethmueller, T; van Noort, M; Szydlarski, M; Rodriguez, J Blanco; Barthol, P; Iniesta, J C del Toro; Gandorfer, A; Gizon, L; Hirzberger, J; Knoelker, M; Pillet, V Martinez; Suarez, D Orozco; Schmidt, W

    2016-01-01

    A dense forest of slender bright fibrils near a small solar active region is seen in high-quality narrow-band Ca II H images from the SuFI instrument onboard the Sunrise balloon-borne solar observatory. The orientation of these slender Ca II H fibrils (SCF) overlaps with the magnetic field configuration in the low solar chromosphere derived by magnetostatic extrapolation of the photospheric field observed with Sunrise/IMaX and SDO/HMI. In addition, many observed SCFs are qualitatively aligned with small-scale loops computed from a novel inversion approach based on best-fit numerical MHD simulation. Such loops are organized in canopy-like arches over quiet areas that differ in height depending on the field strength near their roots.

  12. Two charges on plane in a magnetic field: II. Moving neutral quantum system across magnetic field

    CERN Document Server

    Escobar-Ruiz, M A

    2014-01-01

    The moving neutral system of two Coulomb charges on a plane subject to a constant magnetic field $B$ perpendicular to the plane is considered. It is shown that the composite system of finite total mass is bound for any center-of-mass momentum $P$ and magnetic field strength; the energy of the ground state is calculated accurately using a variational approach. Their accuracy is cross-checked in Lagrange-mesh method for $B=1$\\,a.u. and in a perturbation theory at small $B$ and $P$. The constructed trial function has a property to be a uniform approximation of the exact eigenfunction. For Hydrogen atom and Positronium a double perturbation theory in $B$ and $P$ is developed and the first corrections are found algebraically. A phenomenon of a sharp change of energy behavior for a certain center-of-mass momentum but a fixed magnetic field is indicated.

  13. Sources of the Geomagnetic Field and theModern Data That Enable Their Investigation

    DEFF Research Database (Denmark)

    Olsen, Nils; Hulot, Gauthier; Sabaka, Terence J.

    2010-01-01

    Abstract The geomagnetic field one canmeasure at the Earth’s surface or on board satellites is the sumof contributions frommany different sources.These sources have different physical origins and can be found both below (in the form of electrical currents and magnetized material) and above (only...... sets are available and analyzed in an adequate way, to produce the so-called geomagnetic field models.Here a general overview of the various sources that contribute to the observed geomagnetic field, and of the modern data that enable their investigation via such procedures is provided....

  14. Magnetic field design for a Penning ion source for a 200 keV electrostatic accelerator

    Science.gov (United States)

    Fathi, A.; Feghhi, S. A. H.; Sadati, S. M.; Ebrahimibasabi, E.

    2017-04-01

    In this study, the structure of magnetic field for a Penning ion source has been designed and constructed with the use of permanent magnets. The ion source has been designed and constructed for a 200 keV electrostatic accelerator. With using CST Studio Suite, the magnetic field profile inside the ion source was simulated and an appropriate magnetic system was designed to improve particle confinement. Designed system consists of two ring magnets with 9 mm distance from each other around the anode. The ion source was constructed and the cylindrical magnet and designed magnetic system were tested on the ion source. The results showed that the ignition voltage for ion source with the designed magnetic system is almost 300 V lower than the ion source with the cylindrical magnet. Better particle confinement causes lower voltage discharge to occur.

  15. Stray light in cone beam optical computed tomography: II. Reduction using a convergent light source.

    Science.gov (United States)

    Dekker, Kurtis H; Battista, Jerry J; Jordan, Kevin J

    2016-04-07

    Optical cone beam computed tomography (CBCT) using a broad beam and CCD camera is a fast method for densitometry of 3D optical gel dosimeters. However, diffuse light sources introduce considerable stray light into the imaging system, leading to underestimation of attenuation coefficients and non-uniformities in CT images unless corrections are applied to each projection image. In this study, the light source of a commercial optical CT scanner is replaced with a convergent cone beam source consisting of almost exclusively image forming primary rays. The convergent source is achieved using a small isotropic source and a Fresnel lens. To characterize stray light effects, full-field cone beam CT imaging is compared to fan beam CT (FBCT) using a 1 cm high fan beam aperture centered on the optic axis of the system. Attenuating liquids are scanned within a large 96 mm diameter uniform phantom and in a small 13.5 mm diameter finger phantom. For the uniform phantom, cone and fan beam CT attenuation coefficients agree within a maximum deviation of (1  ±  2)% between mean values over a wide range from 0.036 to 0.43 cm(-1). For the finger phantom, agreement is found with a maximum deviation of (4  ±  2)% between mean values over a range of 0.1-0.47 cm(-1). With the convergent source, artifacts associated with refractive index mismatch and vessel optical features are more pronounced. Further optimization of the source size to achieve a balance between quantitative accuracy and artifact reduction should enable practical, accurate 3D dosimetry, avoiding time consuming 3D scatter measurements.

  16. Stray light in cone beam optical computed tomography: II. Reduction using a convergent light source

    Science.gov (United States)

    Dekker, Kurtis H.; Battista, Jerry J.; Jordan, Kevin J.

    2016-04-01

    Optical cone beam computed tomography (CBCT) using a broad beam and CCD camera is a fast method for densitometry of 3D optical gel dosimeters. However, diffuse light sources introduce considerable stray light into the imaging system, leading to underestimation of attenuation coefficients and non-uniformities in CT images unless corrections are applied to each projection image. In this study, the light source of a commercial optical CT scanner is replaced with a convergent cone beam source consisting of almost exclusively image forming primary rays. The convergent source is achieved using a small isotropic source and a Fresnel lens. To characterize stray light effects, full-field cone beam CT imaging is compared to fan beam CT (FBCT) using a 1 cm high fan beam aperture centered on the optic axis of the system. Attenuating liquids are scanned within a large 96 mm diameter uniform phantom and in a small 13.5 mm diameter finger phantom. For the uniform phantom, cone and fan beam CT attenuation coefficients agree within a maximum deviation of (1  ±  2)% between mean values over a wide range from 0.036 to 0.43 cm-1. For the finger phantom, agreement is found with a maximum deviation of (4  ±  2)% between mean values over a range of 0.1-0.47 cm-1. With the convergent source, artifacts associated with refractive index mismatch and vessel optical features are more pronounced. Further optimization of the source size to achieve a balance between quantitative accuracy and artifact reduction should enable practical, accurate 3D dosimetry, avoiding time consuming 3D scatter measurements.

  17. Radial electric field computations with DKES and neoclassical models in TJ-II stellarator

    Science.gov (United States)

    Martinell, Julio; Gutierrez-Tapia, Cesar; Lopez-Bruna, Daniel

    2015-11-01

    Radial electric fields arise due to the non-ambipolar transport in stellarator plasmas and play an important role in determining some improved confinement regimes. In order to calculate this electric field it is necessary to take all particle fluxes that are not ambipolar. The most important contribution to these fluxes comes from neoclassical transport. Here we use particle fluxes obtained from kinetic equation computations using the code DKES to evaluate the radial electric field profiles for certain discharges of the heliac TJ-II. Experimental profiles for the density and temperatures are used together with the diffusion coefficients obtained with DKES. A similar computation of the electric field is performed with three analytical neoclassical models that use an approximation for the magnetic geometry. The ambipolar electric field from the models is compared with the one given by DKES and we find that they are all qualitatively similar. They are also compared with experimental measurements of the electric field obtained with HIBP. It is shown that, although the electric field is reasonably well reproduced by the neoclassical computations, especially in high temperature regimes, the particle fluxes are not. Thus, neoclassical theory provides good Er estimates in TJ-II. Support from CONACyT 152905 and DGAPA IN109115 projects is acknowledged.

  18. Fan Noise Source Diagnostic Test: LDV Measured Flow Field Results

    Science.gov (United States)

    Podboy, Gary C.; Krupar, Martin J.; Hughes, Christopher E.; Woodward, Richard P.

    2003-01-01

    Results are presented of an experiment conducted to investigate potential sources of noise in the flow developed by two 22-in. diameter turbofan models. The R4 and M5 rotors that were tested were designed to operate at nominal take-off speeds of 12,657 and 14,064 RPMC, respectively. Both fans were tested with a common set of swept stators installed downstream of the rotors. Detailed measurements of the flows generated by the two were made using a laser Doppler velocimeter system. The wake flows generated by the two rotors are illustrated through a series of contour plots. These show that the two wake flows are quite different, especially in the tip region. These data are used to explain some of the differences in the rotor/stator interaction noise generated by the two fan stages. In addition to these wake data, measurements were also made in the R4 rotor blade passages. These results illustrate the tip flow development within the blade passages, its migration downstream, and (at high rotor speeds) its merging with the blade wake of the adjacent (following) blade. Data also depict the variation of this tip flow with tip clearance. Data obtained within the rotor blade passages at high rotational speeds illustrate the variation of the mean shock position across the different blade passages.

  19. Development of PM2.5 source impact spatial fields using a hybrid source apportionment air quality model

    Directory of Open Access Journals (Sweden)

    C. E. Ivey

    2015-01-01

    Full Text Available An integral part of air quality management is knowledge of the impact of pollutant sources on ambient concentrations of particulate matter (PM. There is also a growing desire to directly use source impact estimates in health studies; however, source impacts cannot be directly measured. Several limitations are inherent in most source apportionment methods, which has led to the development of a novel hybrid approach that is used to estimate source impacts by combining the capabilities of receptor modeling (RM and chemical transport modeling (CTM. The hybrid CTM-RM method calculates adjustment factors to refine the CTM-estimated impact of sources at monitoring sites using pollutant species observations and the results of CTM sensitivity analyses, though it does not directly generate spatial source impact fields. The CTM used here is the Community Multi-Scale Air Quality (CMAQ model, and the RM approach is based on the Chemical Mass Balance model. This work presents a method that utilizes kriging to spatially interpolate source-specific impact adjustment factors to generate revised CTM source impact fields from the CTM-RM method results, and is applied to January 2004 over the continental United States. The kriging step is evaluated using data withholding and by comparing results to data from alternative networks. Directly applied and spatially interpolated hybrid adjustment factors at withheld monitors had a correlation coefficient of 0.89, a linear regression slope of 0.83 ± 0.02, and an intercept of 0.14 ± 0.02. Refined source contributions reflect current knowledge of PM emissions (e.g., significant differences in biomass burning impact fields. Concentrations of 19 species and total PM2.5 mass were reconstructed for withheld monitors using directly applied and spatially interpolated hybrid adjustment factors. The mean concentrations of total PM2.5 for withheld monitors were 11.7 (± 8.3, 16.3 (± 11, 8.59 (± 4.7, and 9.20 (± 5.7 μg m−3

  20. The Young principle and integration-masked lumped sources of a diffracted field

    Science.gov (United States)

    Urusovskii, I. A.

    2016-11-01

    A methodologically simple modification of the Young principle is proposed for describing diffracted field formation in problems of wave diffraction by the sharp edges of screens and wedges without using Sommerfeld's two-sheeted space. The method of determining the diffracted field constructs the derivative of the field by introducing lumped sources positioned at given scattering edges with subsequent integration of the constructed field along the directions parallel to the wave fronts of the incident plane wave.

  1. The neutron distribution system of the new ultra-cold neutron source at the FRM II

    Energy Technology Data Exchange (ETDEWEB)

    Wlokka, Stephan; Frei, Andreas [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Techische Universitaet Muenchen, Lichtenbergstrasse 1, D-85747 Garching (Germany); Fierlinger, Peter; Paul, Stephan [Physik Department, Technische Universitaet Muenchen, James-Franck-Strasse 1, D-85748 Garching (Germany); Geltenbort, Peter [Institut Laue-Langevin, BP 156, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2013-07-01

    Ultra-cold neutrons (UCN) are neutrons which are totally reflected from a given material surface. Typical energies of UCN are below 300 neV and velocities below 8 m/s. Thus they can be stored in material or magnetic bottles for several hundreds of seconds. As such, UCN are excellent laboratories to study fundamental parameters, e.g. the free neutron lifetime or the electric dipole moment of the neutron. The new UCN source foreseen at the FRM II will deliver high UCN densities to four experimental areas. Hence a mechanism to distribute as many UCN as possible to these areas is needed. We have developed a high efficiency UCN switch for this purpose. This talk reports about a series of measurements conducted with this switch. There have been three types of measurements, testing the transmission, storage and surface properties of the switch.

  2. Boîtes quantiques II-VI comme sources de photons uniques

    Science.gov (United States)

    Couteau, C.; Moehl, S.; Tinjod, F.; Suffczynski, J.; Romestain, R.; Vial, J.-C.; Gérard, J.-M.; Kheng, K.; Poizat, J.-P.

    2004-11-01

    Dans le cadre de l'information et de la communication quantique, la nécessité d'avoir des photons uniques monomodes et à la demande se révèle cruciale. De récents travaux théoriques ont montré la possibilité de réaliser des portes logiques quantiques n'utilisant que de l'optique linéaire. C'est dans ce contexte que s'insère notre travail sur l'élaboration et l'utilisation de boîtes quantiques semi-conductrices II-VI comme “pistolet” à photons. Des expériences de dégroupement et d'interférences à 2 photons sont les premiers pas nécessaires pour caractériser notre source.

  3. Social Work Program. Field Placement Manual for Social Work Field Placement I, Social Work Field Placement II.

    Science.gov (United States)

    Miller, Howard J.; And Others

    This document is a manual for a social work field placement program. The social work field placement is described as a learning experience designed to translate the students' interests, interpersonal abilities, and academic knowledge and theory into the capability of enabling others to solve problems. Expectations of skills to be learned in the…

  4. THE COORDINATED RADIO AND INFRARED SURVEY FOR HIGH-MASS STAR FORMATION. II. SOURCE CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    Purcell, C. R.; Hoare, M. G.; Lumsden, S. L.; Urquhart, J. S. [School of Physics and Astronomy, E.C. Stoner Building, University of Leeds, Leeds LS2 9JT (United Kingdom); Cotton, W. D. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Chandler, C. [National Radio Astronomy Observatory, Array Operations Center, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801-0387 (United States); Churchwell, E. B. [The University of Wisconsin, Department of Astronomy, 475 North Charter Street, Madison, WI 53706 (United States); Diamond, P.; Fuller, G.; Garrington, S. T. [Jodrell Bank Centre for Astrophysics, The Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Rd, Manchester, M13 9PL (United Kingdom); Dougherty, S. M. [National Research Council of Canada, Herzberg Institute for Astrophysics, Dominion Radio Astrophysical Observatory, P.O. Box 248, Penticton, British Columbia V2A 6J9 (Canada); Fender, R. P. [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Gledhill, T. M. [Science and Technology Research Institute, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Goldsmith, P. F. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Hindson, L. [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia); Jackson, J. M. [Astronomy Department, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Kurtz, S. E. [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico - Morelia, Apartado Postal 3-72, C.P. 58090 Morelia, Michoacan (Mexico); Marti, J., E-mail: C.R.Purcell@leeds.ac.uk [Departamento de Fisica, EPSJ, Universidad de Jaen, Campus Las Lagunillas s/n, Edif. A3, E-23071 Jaen (Spain); and others

    2013-03-01

    The CORNISH project is the highest resolution radio continuum survey of the Galactic plane to date. It is the 5 GHz radio continuum part of a series of multi-wavelength surveys that focus on the northern GLIMPSE region (10 Degree-Sign < l < 65 Degree-Sign ), observed by the Spitzer satellite in the mid-infrared. Observations with the Very Large Array in B and BnA configurations have yielded a 1.''5 resolution Stokes I map with a root mean square noise level better than 0.4 mJy beam{sup -1}. Here we describe the data-processing methods and data characteristics, and present a new, uniform catalog of compact radio emission. This includes an implementation of automatic deconvolution that provides much more reliable imaging than standard CLEANing. A rigorous investigation of the noise characteristics and reliability of source detection has been carried out. We show that the survey is optimized to detect emission on size scales up to 14'' and for unresolved sources the catalog is more than 90% complete at a flux density of 3.9 mJy. We have detected 3062 sources above a 7{sigma} detection limit and present their ensemble properties. The catalog is highly reliable away from regions containing poorly sampled extended emission, which comprise less than 2% of the survey area. Imaging problems have been mitigated by down-weighting the shortest spacings and potential artifacts flagged via a rigorous manual inspection with reference to the Spitzer infrared data. We present images of the most common source types found: H II regions, planetary nebulae, and radio galaxies. The CORNISH data and catalog are available online at http://cornish.leeds.ac.uk.

  5. Crystal-field spectra of 3d super n impurities in II-VI and III-V compound semiconductors.

    Science.gov (United States)

    Allen, J. W.; Baranowski, J. M.; Pearson, G. L.

    1967-01-01

    Impurity crystal-field spectra in II-VI and III- V compound semiconductors used to predict unexplored systems spectra impurity crystal-field spectra in II-VI and III-V compound semiconductors used to predict unexplored systems spectra

  6. Periodic variable stars in CoRoT field LRa02 observed with BEST II

    CERN Document Server

    Kabath, P; Rauer, H; Pasternacki, T; Csizmadia, Sz; Chini, R; Lemke, R; Murphy, M; Fruth, T; Titz, R; Eigmueller, P

    2009-01-01

    The Berlin Exoplanet Search Telescope II (BEST II) is a small wide field-of-view photometric survey telescope system located at the Observatorio Cerro Armazones, Chile. The high duty cycle combined with excellent observing conditions and millimagnitude photometric precision makes this instrument suitable for ground based support observations for the CoRoT space mission. Photometric data of the CoRoT LRa02 target field collected between November 2008 and March 2009 were analysed for stellar variability. The presented results will help in the future analysis of the CoRoT data, particularly in additional science programs related to variable stars. BEST II observes selected CoRoT target fields ahead of the space mission. The photometric data acquired are searched for stellar variability, periodic variable stars are identified with time series analysis of the obtained stellar light curves. We obtained the light curves of 104335 stars in the CoRoT LRa02 field over 41 nights. Variability was detected in light curves...

  7. Amplification of magnetic fields in a primordial H II region and supernova

    Science.gov (United States)

    Koh, Daegene; Wise, John H.

    2016-10-01

    Magnetic fields permeate the Universe on all scales and play a key role during star formation. We study the evolution of magnetic fields around a massive metal-free (Population III) star at z ˜ 15 during the growth of its H II region and subsequent supernova explosion by conducting three cosmological magnetohydrodynamics simulations with radiation transport. Given the theoretical uncertainty and weak observational constraints of magnetic fields in the early universe, we initialize the simulations with identical initial conditions only varying the seed field strength. We find that magnetic fields grow as ρ2/3 during the gravitational collapse preceding star formation, as expected from ideal spherical collapse models. Massive Population III stars can expel a majority of the gas from the host halo through radiative feedback, and we find that the magnetic fields are not amplified above the spherical collapse scaling relation during this phase. However, afterwards when its supernova remnant can radiatively cool and fragment, the turbulent velocity field in and around the shell causes the magnetic field to be significantly amplified on average by ˜100 in the shell and up to 6 orders of magnitude behind the reverse shock. Within the shell, field strengths are on the order of a few nG at a number density of 1 cm-3. We show that this growth is primarily caused by small-scale dynamo action in the remnant. These strengthened fields will propagate into the first generations of galaxies, possibly affecting the nature of their star formation.

  8. Ablation plasma transport using multicusp magnetic field for laser ion source

    Science.gov (United States)

    Takahashi, K.; Umezawa, M.; Uchino, T.; Ikegami, K.; Sasaki, T.; Kikuchi, T.; Harada, N.

    2016-05-01

    We propose a plasma guiding method using multicusp magnetic field to transport the ablation plasma keeping the density for developing laser ion sources. To investigate the effect of guiding using the magnetic field on the ablation plasma, we demonstrated the transport of the laser ablation plasma in the multicusp magnetic field. The magnetic field was formed with eight permanent magnets and arranged to limit the plasma expansion in the radial direction. We investigated the variation of the plasma ion current density and charge distribution during transport in the magnetic field. The results indicate that the plasma is confined in the radial direction during the transport in the multicusp magnetic field.

  9. The discovery of new AGN candidates within the field of Fermi unassociated γ-ray sources

    Science.gov (United States)

    Fujinaga, Yoshitaka; Niinuma, Kotaro; Kimura, Atsushi; Fujisawa, Kenta; Oyama, Tomoaki; Mizuno, Syota; Kono, Yusuke; Takemura, Shinji; Sawada-Satoh, Satoko; Akutagawa, Kengo; Sugiyama, Koichiro; Motogi, Kazuhito; Fukuzaki, Yoshihiro

    2016-10-01

    In this paper, we report on the discovery of 26 new radio sources located within positional error range of unassociated γ-ray sources listed in the Fermi Large Area Telescope Second Source Catalog (2FGL catalog) by very long baseline interferometry (VLBI) observations. To search for new γ-ray AGN candidates, we conducted e-VLBI observations for 845 radio sources located in the field of 149 Fermi unassociated γ-ray sources at high galactic latitude, using the Japanese VLBI Network (JVN) at 8.4 GHz with a noise level of approximately 2 mJy. As a result of our JVN observations, we detected 29 VLBI sources having a brightness temperature of TB > 106 K within positional error of 28 γ-ray sources in the 2FGL catalog. These high brightness temperatures imply that the newly detected sources are possibly GeV γ-ray AGNs, such as most of 2FGL sources, which have already been classified as AGNs. Also, precise radio coordinates make it possible to identify the multiwavelength counterparts to the newly detected VLBI sources. Their color-color diagrams derived from Wide-field Infrared Survey Explorer photometric data of these sources imply that eight out of all sources we detected would be classified as γ-ray blazars.

  10. Cyclotron Line Features from Near-Critical Fields II on the Effect of Anisotropic Radiation Fields

    CERN Document Server

    Araya-Gochez, R A; Araya-Gochez, Rafael A.; Harding, Alice K.

    2000-01-01

    We assess the impact of radiation anisotropy on the line shapes that result from relativistic magnetic Compton scattering in the low-density/high-field regime. A Monte Carlo implementation of radiation transport allows for spatial diffusion of photons in arbitrary geometries and accounts for relativistic angular redistribution. The cross section includes natural line widths and photon "spawning" from up to fourth harmonic photons. In our first paper we noted that even if the photon injection is isotropic a strongly anisotropic radiation field rapidly ensues. We now investigate the angular distribution of cyclotron spectra emerging from an internally irradiated magnetized plasma with a prescribed global geometry (either cylindrical or plane parallel) and the effects of anisotropic photon injection on the line shapes. Varying the input angular distribution permits a better understanding of the line formation process in more realistic scenarios where the radiative mechanisms are influenced by the intrinsic aniso...

  11. Radiofrequency hydrogen ion source with permanent magnets providing axial magnetic field.

    Science.gov (United States)

    Oikawa, Kohei; Saito, Yuta; Komizunai, Shota; Takahashi, Kazunori; Ando, Akira

    2014-02-01

    Uniform axial magnetic field of about 70 G is applied to a radiofrequency (rf) hydrogen ion source by arrays of permanent magnets. The plasma density and electron temperature downstream of the source and near the magnetic filter are compared with those in the previously described ion source, where the axial field has been applied by two solenoids. The source is operated at ∼350 kHz and above 10 kW rf power with a field-effect-transistor-based invertor power supply in 1.5 Pa hydrogen. The results show that the plasma density of ∼10(19) m(-3) near the source exit and ∼10(18) m(-3) near the magnetic filter can be obtained, which are higher than those with the solenoids.

  12. Radiofrequency hydrogen ion source with permanent magnets providing axial magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Oikawa, Kohei, E-mail: oikawa@ecei.tohoku.ac.jp; Saito, Yuta; Komizunai, Shota; Takahashi, Kazunori; Ando, Akira [Department of Electrical Engineering, Tohoku University, Sendai 980-8579 (Japan)

    2014-02-15

    Uniform axial magnetic field of about 70 G is applied to a radiofrequency (rf) hydrogen ion source by arrays of permanent magnets. The plasma density and electron temperature downstream of the source and near the magnetic filter are compared with those in the previously described ion source, where the axial field has been applied by two solenoids. The source is operated at ∼350 kHz and above 10 kW rf power with a field-effect-transistor-based invertor power supply in 1.5 Pa hydrogen. The results show that the plasma density of ∼10{sup 19} m{sup −3} near the source exit and ∼10{sup 18} m{sup −3} near the magnetic filter can be obtained, which are higher than those with the solenoids.

  13. AMUSE-Field II. Nucleation of early-type galaxies in the field vs. cluster environment

    CERN Document Server

    Baldassare, Vivienne F; Miller, Brendan P; Plotkin, Richard M; Treu, Tommaso; Valluri, Monica; Woo, Jong-Hak

    2014-01-01

    The optical light profiles of nearby early type galaxies are known to exhibit a smooth transition from nuclear light deficits to nuclear light excesses with decreasing galaxy mass, with as much as 80 per cent of the galaxies with stellar masses below 10^10 Msun hosting a massive nuclear star cluster. At the same time, while all massive galaxies are thought to harbor nuclear super-massive black holes (SMBHs), observational evidence for SMBHs is slim at the low end of the mass function. Here, we explore the environmental dependence of the nucleation fraction by comparing two homogeneous samples of nearby field vs. cluster early type galaxies with uniform Hubble Space Telescope (HST) coverage. Existing Chandra X-ray Telescope data for both samples yield complementary information on low-level accretion onto nuclear SMBHs. Specifically, we report on dual-band (F475W & F850LP) Advanced Camera for Surveys (ACS) imaging data for 28 out of the 103 field early type galaxies that compose the AMUSE-Field Chandra surv...

  14. Patch near-field acoustic holography: The influence of acoustic contributions from outside the source

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn; Zhang, Yong-Bin

    2009-01-01

    is of particular interest (known as the “patch” or “source patch”). The area of the source beyond this patch is not of interest in the analysis. However, its acoustic output may nevertheless contribute to the total sound field in the measurement plane, and influence the reconstruction of the field close...... that an acceptable reconstruction of the normal velocity can be achieved if the contributions from beyond the patch area are accounted for.......It is a requirement of conventional Near-field Acoustic Holography that the measurement area covers the entire surface of the source. In the case of Patch Near-field Acoustic Holography (patch NAH), the measurement area can be reduced to cover only a specific area of the source which...

  15. A study of the properties of twin radio arms of FR-II extragalactic radio sources within z≤1-II (dynamical properties)

    Science.gov (United States)

    Onuchukwu, C. C.; Ubachukwu, A. A.

    2017-04-01

    We carried out a comparative study on the dynamical properties of the Longer Arm (LA) and the Shorter Arm (SA) of different classes of FR-II radio sources (Broad Line Radio Galaxies (BLRG), Quasars (Q), Narrow Line Radio Galaxies (NLRG) and Low Excitation Radio Galaxies (LERG)) based on self-similar model of time evolution of the radio lobes and hotspot properties of radio sources, using the power-law expression for the dependence of hotspot size (D_{hs}), the advance velocity of the hotspot (v_{hs}) and hotspot luminosity (PL) on the core-lobe length (DL). Using observational values of D_{hs}, PL and DL we constrained the exponents of these power-law relations for the LA and SA. We also estimated the hotspot pressure, (p_{hs}), cocoon pressure within the lobe (p_{cc}), the ratio of the hotspot pressure to the cocoon pressure (p_{hc}), the cocoon volume (Vcc), the energy density within the cocoon (u_{cc}), the equipartition magnetic field (B_{em}) in the lobe, the particle number density at the hotspot (n_{hs}), the external density profile (ρ _{ext}) and the kinetic jet power (Q_{jet}) for the LA and the SA. Linear regression analyses indicate a tight correlation between the D_{hs} and the DL of LA for all classes of radio sources with r˜0.5-0.8. Similar result was obtained for SA except for that of Q with r˜ 0.2. For P_{hs} and DL correlation, the result indicates a mild negative correlation that seems stronger for the SA (r˜-0.3 to -0.6) than LA (r˜-0.2 to -0.4) for all the different classes of radio sources. Comparing the values of ρ_{ext}, B_{em}, uB, p_{hs}, p_{cc}, Vcc, and u_{cc} between SA side and LA side, indicate that the SA values of the parameters are higher than those of LA; while (p_{hs}) showed higher values in LA than SA for all the different classes of radio sources. Generally, the hotspot has a larger volume on the LA side than on the SA side except for NLRG, while the hotspot of the SA side contains more particle per unit volume than the

  16. MAGNETIC FIELD GRADIENT EFFECTS ON ION FLUX BEHAVIORS IN ECR PLASMA SOURCES

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The available electron cyclotron resonance plasma source has been simulated in two-dimensional configuration space (z, r) and three-dimensional velocity space (Vz, Vr Vθ). The simulation is focused on the magnetic field gradient effects on ion flux behaviors in electron cyclotron resonance plasma sources. The simulation results show that, when the magnetic field gradients increase, electron temperature, plasma density, ionization rate, and ion flux in Zdirection would decrease, while ion energy and plasma potential would increase.

  17. Near- and Far-Field Response to Compact Acoustic Sources in Stratified Convection Zones

    OpenAIRE

    Cally, Paul S.

    2013-01-01

    The role of the acoustic continuum associated with compact sources in the Sun's interior wave field is explored for a simple polytropic model. The continuum produces a near-field acoustic structure -- the so-called `acoustic jacket' -- that cannot be represented by a superposition of discrete normal modes. Particular attention is paid to monochromatic point sources of various frequency and depth, and to the surface velocity power that results, both in the discrete f- and p-mode spectrum and i...

  18. Computer simulation of the emission process of some field emission alloy ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Georgieva, S.; Vichev, R.; Drandarov, N. [Bulgarian Academy of Sciences, Sofia (Bulgaria)

    1996-10-01

    The ion emission process from InGa, AuBe and AuSi field emission alloy ion sources (LAIS) is simulated. Field strength is calculated using the SOC model. Paraxial source size, beam spot size, energy and angular distributions are estimated. The effects on the emission characteristics of Coulomb interaction between ions are investigated, and the strong influences of ion mass and charge are also shown. (Author).

  19. The VLA-COSMOS Survey: II. Source Catalog of the Large Project

    CERN Document Server

    Schinnerer, E; Carilli, C L; Bondi, M; Ciliegi, P; Jahnke, K; Scoville, N Z; Aussel, H; Bertoldi, F; Blain, A W; Impey, C D; Koekemoer, A M; Lefèvre, O; Urry, C M

    2006-01-01

    The VLA-COSMOS large project is described and its scientific objective is discussed. We present a catalog of ~ 3,600 radio sources found in the 2deg^2 COSMOS field at 1.4 GHz. The observations in the VLA A and C configuration resulted in a resolution of 1.5''x1.4'' and a mean rms noise of ~ 10.5(15) uJy/beam in the central 1(2)deg^2. 80 radio sources are clearly extended consisting of multiple components, and most of them appear to be double-lobed radio galaxies. The astrometry of the catalog has been thoroughly tested and the uncertainty in the relative and absolute astrometry are 130mas and <55mas, respectively.

  20. Assessing Model Characterization of Single Source Secondary Pollutant Impacts Using 2013 SENEX Field Study Measurements.

    Science.gov (United States)

    Baker, Kirk R; Woody, Matthew C

    2017-03-15

    Aircraft measurements made downwind from specific coal fired power plants during the 2013 Southeast Nexus field campaign provide a unique opportunity to evaluate single source photochemical model predictions of both O3 and secondary PM2.5 species. The model did well at predicting downwind plume placement. The model shows similar patterns of an increasing fraction of PM2.5 sulfate ion to the sum of SO2 and PM2.5 sulfate ion by distance from the source compared with ambient based estimates. The model was less consistent in capturing downwind ambient based trends in conversion of NOX to NOY from these sources. Source sensitivity approaches capture near-source O3 titration by fresh NO emissions, in particular subgrid plume treatment. However, capturing this near-source chemical feature did not translate into better downwind peak estimates of single source O3 impacts. The model estimated O3 production from these sources but often was lower than ambient based source production. The downwind transect ambient measurements, in particular secondary PM2.5 and O3, have some level of contribution from other sources which makes direct comparison with model source contribution challenging. Model source attribution results suggest contribution to secondary pollutants from multiple sources even where primary pollutants indicate the presence of a single source.

  1. Effect of three common sources of electromagnetic fields on health

    Energy Technology Data Exchange (ETDEWEB)

    Mortazavi, S.M.J.; Ahmadi, J.; Behnejad, B. [Rafsanjan Univ. of Medical Sciences, Rafsanjan (Iran, Islamic Republic of)

    2006-07-01

    Background And Aims: The number of people complaining about different symptoms that may be associated with exposure to electromagnetic fields (E.M.F.) has increased rapidly during the past years. Students use both mobile phones and video display terminals frequently. The purpose of this study was to investigate the association of mobile phone use and E.M.F. health hazards. Methods: Basic demographic data and self-reported symptoms were sought using a questionnaire administered to all apparently healthy students at Rafsanjan University of Medical Sciences (R.U.M.S.) and Vali-e-Asr University (V.A.U.). Questions ab out some major confounding factors such as age, gender, amount of video display terminal work were also included. All symptoms were self reported and there was no medical examination. Exact Fisher Test was used for data analysis. Results: 518 complete responses were collected. The responders comprised 317 Vali-e-Asr students (61.2%) and 201 R.U.M.S. students (38.8%). The gender distribution was male 175 33.8%), and female 343 (66.2 %). Thirty percent of the students had been using mobile phones (26% in female students and 38.2% in males, P<0.01). There was a significant difference between the frequency of mobile phone users in medical/par a medical (41.3%) and non-medical (23%) students (P<0. 001). Thirty six percent of the students had been using cord-less phones (no statistically significant gender difference). 56.3% used cathode ray tubes (C.R.T.) as computer monitors (47.1% in female students and 74.3% in males, P<0.001). Regarding self-reported symptoms, headache (52%), fatigue (35%), difficulties in concentration (31.7%), vertigo/dizziness (30%), attention disorders (28.8%), nervousness (28.1%), palpitation (14.7%), low back pain (14.3%), myalgia (12.3%), and tinnitus (10%) were the main self-reported symptoms. There were significantly more women with headache, dizziness, myalgia, and nervousness than men (in each case P<0.001). No significant

  2. Applying the Background-Source separation algorithm to Chandra Deep Field South data

    CERN Document Server

    Guglielmetti, F; Fischer, R; Rosati, P; Tozzi, P

    2012-01-01

    A probabilistic two-component mixture model allows one to separate the diffuse background from the celestial sources within a one-step algorithm without data censoring. The background is modeled with a thin-plate spline combined with the satellite's exposure time. Source probability maps are created in a multi-resolution analysis for revealing faint and extended sources. All detected sources are automatically parametrized to produce a list of source positions, fluxes and morphological parameters. The present analysis is applied to the Chandra Deep Field South 2 Ms public released data. Within its 1.884 ks of exposure time and its angular resolution (0.984 arcsec), the Chandra Deep Field South data are particularly suited for testing the Background-Source separation algorithm.

  3. Photonic forces in the near field of statistically homogeneous fluctuating sources

    CERN Document Server

    Aunon, Juan Miguel

    2012-01-01

    Electromagnetic sources, as e.g. lasers, antennas, diffusers or thermal sources, produce a wavefield that interacts with objects to transfer them its momentum. We show that the photonic force exerted on a small particle in the near field of a planar statistically homogeneous fluctuating source uniquely depends and acts along the coordinate perpendicular to its surface. The gradient part of this force is contributed by only the evanescent components of the emitted field, its sign being opposite to that of the real part of the particle polarizability. The non-conservative force part is uniquely due to the propagating components, being repulsive and constant. Also, the source coherence length adds a degree of freedom since it largely affects these forces. The excitation of plasmons in the source surface drastically enhances the gradient force. Hence, partially coherent wavefields from fluctuating sources constitute new concepts for particle manipulation at the subwavelength scale

  4. Exploring the origin of magnetic fields in massive stars: II. New magnetic field measurements in cluster and field stars

    CERN Document Server

    Hubrig, S; Ilyin, I; Kharchenko, N V; Oskinova, L M; Langer, N; Gonzalez, J F; Kholtygin, A F; Briquet, M

    2013-01-01

    Theories on the origin of magnetic fields in massive stars remain poorly developed, because the properties of their magnetic field as function of stellar parameters could not yet be investigated. To investigate whether magnetic fields in massive stars are ubiquitous or appear only in stars with a specific spectral classification, certain ages, or in a special environment, we acquired 67 new spectropolarimetric observations for 30 massive stars. Among the observed sample, roughly one third of the stars are probable members of clusters at different ages, whereas the remaining stars are field stars not known to belong to any cluster or association. Spectropolarimetric observations were obtained during four different nights using the low-resolution spectropolarimetric mode of FORS2 (FOcal Reducer low dispersion Spectrograph) mounted on the 8-m Antu telescope of the VLT. Furthermore, we present a number of follow-up observations carried out with the high-resolution spectropolarimeters SOFIN mounted at the Nordic O...

  5. Field ionization characteristics of an ion source array for neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    Bargsten Johnson, B.; Schwoebel, P. R. [University of New Mexico, Albuquerque, New Mexico 87131 (United States); Resnick, P. J. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Holland, C. E. [SRI International, Menlo Park, California 94025 (United States); Hertz, K. L. [Sandia National Laboratories, Livermore, California 94551 (United States); Chichester, D. L. [Idaho National Laboratory, Idaho Falls, Idaho 83415 (United States)

    2013-11-07

    A new deuterium ion source is being developed to improve the performance of existing compact neutron generators. The ion source is a microfabricated array of metal tips with an integrated gate (i.e., grid) and produces deuterium ions by field ionizing (or field desorbing) a supply of deuterium gas. Deuterium field ion currents from arrays at source temperatures of 77 K and 293 K are studied. Ion currents from single etched-wire tips operating under the same conditions are used to help understand array results. I-F characteristics of the arrays were found to follow trends similar to those of the better understood single etched-wire tip results; however, the fields achieved by the arrays are limited by electrical breakdown of the structure. Neutron production by field ionization at 293 K was demonstrated for the first time from microfabricated array structures with integrated gates.

  6. Field ionization characteristics of an ion source array for neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    B. Bargsten Johnson; P. R. Schwoebel; P. J. Resnick; C. E. Holland; L. Hertz; D. L. Chichester

    2013-11-01

    A new deuterium ion source is being developed to improve the performance of existing compact neutron generators. The ion source is a microfabricated array of metal tips with an integrated gate (i.e., grid) and produces deuterium ions by field ionizing (or field desorbing) a supply of deuterium gas. Deuterium field ion currents from arrays at source temperatures of 77?K and 293?K are studied. Ion currents from single etched-wire tips operating under the same conditions are used to help understand array results. I-F characteristics of the arrays were found to follow trends similar to those of the better understood single etched-wire tip results; however, the fields achieved by the arrays are limited by electrical breakdown of the structure. Neutron production by field ionization at 293?K was demonstrated for the first time from microfabricated array structures with integrated gates.

  7. Field ionization characteristics of an ion source array for neutron generators

    Science.gov (United States)

    Bargsten Johnson, B.; Schwoebel, P. R.; Resnick, P. J.; Holland, C. E.; Hertz, K. L.; Chichester, D. L.

    2013-11-01

    A new deuterium ion source is being developed to improve the performance of existing compact neutron generators. The ion source is a microfabricated array of metal tips with an integrated gate (i.e., grid) and produces deuterium ions by field ionizing (or field desorbing) a supply of deuterium gas. Deuterium field ion currents from arrays at source temperatures of 77 K and 293 K are studied. Ion currents from single etched-wire tips operating under the same conditions are used to help understand array results. I-F characteristics of the arrays were found to follow trends similar to those of the better understood single etched-wire tip results; however, the fields achieved by the arrays are limited by electrical breakdown of the structure. Neutron production by field ionization at 293 K was demonstrated for the first time from microfabricated array structures with integrated gates.

  8. Reproduction of nearby sources by imposing true interaural differences on a sound field control approach

    DEFF Research Database (Denmark)

    Badajoz, Javier; Chang, Ji-ho; Agerkvist, Finn T.

    2015-01-01

    In anechoic conditions, the Interaural Level Difference (ILD) is the most significant auditory cue to judge the distance to a sound source located within 1 m of the listener's head. This is due to the unique characteristics of a point source in its near field, which result in exceptionally high, ...

  9. Sources of the Geomagnetic Field and the Modern Data That Enable Their Investigation

    DEFF Research Database (Denmark)

    Olsen, Nils; Hulot, Gauthier; Sabaka, Terence J.

    2014-01-01

    The geomagnetic field one can measure at the Earth’s surface or on board satellites is the sum of contributions from many different sources. These sources have different physical origins and can be found both below (in the form of electrical currents and magnetized material) and above (only in th...

  10. Effects of the near field on source-independent q estimation

    NARCIS (Netherlands)

    Shigapov, R.; Kashtan, B.; Droujinine, A.; Mulder, W.A.

    2013-01-01

    We consider the problem of Q estimation from microseismic and from perforation shot data. Assuming that the source wavelet is not well known, we focused on the spectral ratio method and on source-independent viscoelastic full waveform inversion. We derived 3-D near-field approximations of monopole a

  11. Search for point sources of high energy neutrinos with final data from AMANDA-II

    Science.gov (United States)

    Abbasi, R.; Ackermann, M.; Adams, J.; Ahlers, M.; Ahrens, J.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Baret, B.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Becka, T.; Becker, J. K.; Becker, K.-H.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.; Böser, S.; Botner, O.; Braun, J.; Breder, D.; Burgess, T.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; Davour, A.; Day, C. T.; Depaepe, O.; de Clercq, C.; Demirörs, L.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; De Young, T.; Diaz-Velez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Gerhardt, L.; Gladstone, L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hardtke, R.; Hasegawa, Y.; Heise, J.; Helbing, K.; Hellwig, M.; Herquet, P.; Hickford, S.; Hill, G. C.; Hodges, J.; Hoffman, K. D.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hughey, B.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hundertmark, S.; Hussain, S.; Imlay, R. L.; Inaba, M.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kawai, H.; Kelley, J. L.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Klepser, S.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kuehn, K.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Lauer, R.; Leich, H.; Leier, D.; Lewis, C.; Lucke, A.; Lundberg, J.; Lünemann, J.; Madsen, J.; Maruyama, R.; Mase, K.; Matis, H. S.; McParland, C. P.; Meagher, K.; Meli, A.; Merck, M.; Messarius, T.; Mészáros, P.; Miyamoto, H.; Mohr, A.; Montaruli, T.; Morse, R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Patton, S.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Pohl, A. C.; Porrata, R.; Potthoff, N.; Pretz, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Razzaque, S.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Robbins, W. J.; Rodriguez, J.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Rutledge, D.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Satalecka, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schultz, O.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Smith, A. J.; Song, C.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sulanke, K.-H.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Tluczykont, M.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; Viscomi, V.; Vogt, C.; Voigt, B.; Walck, C.; Waldenmaier, T.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebusch, C. H.; Wiedemann, C.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh, G.; Yoshida, S.

    2009-03-01

    We present a search for point sources of high energy neutrinos using 3.8 yr of data recorded by AMANDA-II during 2000-2006. After reconstructing muon tracks and applying selection criteria designed to optimally retain neutrino-induced events originating in the northern sky, we arrive at a sample of 6595 candidate events, predominantly from atmospheric neutrinos with primary energy 100 GeV to 8 TeV. Our search of this sample reveals no indications of a neutrino point source. We place the most stringent limits to date on E-2 neutrino fluxes from points in the northern sky, with an average upper limit of E2Φνμ+ντ≤5.2×10-11TeVcm-2s-1 on the sum of νμ and ντ fluxes, assumed equal, over the energy range from 1.9 TeV to 2.5 PeV.

  12. NuSTAR, XMM-Newton and Suzaku Observations of the Ultraluminous X-Ray Source Holmberg II X-1

    DEFF Research Database (Denmark)

    Walton, D. J.; Middleton, M. J.; Rana, V.;

    2015-01-01

    We present the first broadband 0.3-25.0 keV X-ray observations of the bright ultraluminous X-ray source (ULX) Holmberg II X-1, performed by NuSTAR, XMM-Newton, and Suzaku in 2013 September. The NuSTAR data provide the first observations of Holmberg II X-1 above 10 keV and reveal a very steep high...

  13. A Wide-Field View of Leo II -- A Structural Analysis Using the SDSS

    CERN Document Server

    Coleman, Matthew G; Rix, Hans-Walter; Grebel, Eva K; Koch, Andreas

    2007-01-01

    Using SDSS I data, we have analysed the stellar distribution of the Leo II dwarf spheroidal galaxy (distance of 233 kpc) to search for evidence of tidal deformation. The existing SDSS photometric catalogue contains gaps in regions of high stellar crowding, hence we filled the area at the centre of Leo II using the DAOPHOT algorithm applied to the SDSS images. The combined DAOPHOT-SDSS dataset contains three-filter photometry over a 4x4 square degree region centred on Leo II. By defining a mask in three-filter colour-magnitude space, we removed the majority of foreground field stars. We have measured the following Leo II structural parameters: a core radius of r_c = 2.64 +/- 0.19 arcmin (178 +/- 13 pc), a tidal radius of r_t = 9.33 +/- 0.47 arcmin (632 +/- 32 pc) and a total V-band luminosity of L_V = (7.4 +/- 2.0) times 10^5 L_sun (M_V = -9.9 +/- 0.3). Our comprehensive analysis of the Leo II structure did not reveal any significant signs of tidal distortion. The internal structure of this object contains onl...

  14. Spitzer mid-infrared point sources in the fields of nearby galaxies

    CERN Document Server

    Williams, S J

    2016-01-01

    We present $Spitzer$ IRAC mid-infrared point source catalogs for mosaics covering the fields of the nearby ($\\lesssim$4 Mpc) galaxies NGC 55, NGC 253, NGC 2366, NGC 4214, and NGC 5253. We detect a total of 20159 sources in these five fields. Point spread function photometry was performed on sources detected in both $Spitzer$ IRAC 3.6 $\\mu$m and 4.5 $\\mu$m bands at greater than 3$\\sigma$ above background. These data were then supplemented by aperture photometry in the IRAC 5.8 $\\mu$m and 8.0 $\\mu$m bands conducted at the positions of the shorter wavelength sources. For sources with no detected object in the longer wavelengths, we estimated magnitude limits based on the local sky background. The individual galaxy point source breakdown is the following: NGC 55, 8746 sources; NGC 253, 9001 sources; NGC 2366, 505 sources; NGC 4214, 1185 sources; NGC 5253, 722 sources. The completeness limits of the full catalog vary with bandpass and were found to be $m_{3.6}=18.0$, $m_{4.5}=17.5$, $m_{5.8}=17.0$, and $m_{8.0}=16...

  15. Measurements of the neutron brightness from a phase II solid methane moderator at the LENS neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Shin Yunchang, E-mail: yunchang.shin@yale.ed [Department of Physics, Indiana University Bloomington, IN 47408 (United States); Department of Physics, Yale University, New Haven, CT 06511 (United States); Lavelle, C.M.; Mike Snow, W.; Baxter, David V.; Tong Xin; Yan Haiyang [Department of Physics, Indiana University Bloomington, IN 47408 (United States); Leuschner, Mark [ProCure 420 North Walnut Street Bloomington, IN 47404 (United States)

    2010-08-21

    Measurements of the neutron brightness from a solid methane moderator were performed at the Low Energy Neutron Source (LENS) at the Indiana University Cyclotron Facility (IUCF) to characterize the source and to test our new neutron scattering model of phase II solid methane . A time-of-flight method was used to measure the neutron energy spectrum from the moderator in the energy range of 0.1 meV {approx}1eV. Neutrons were counted with a high efficiency {sup 3}He detector. The solid methane in the moderator occupied phase II and the energy spectra were measured at 20 K and 4 K. We tested our newly developed scattering kernels for phase II solid methane by calculating the neutron brightness expected from the methane moderator at the LENS neutron source using MCNP (Monte Carlo N-particle Transport Code). Within the accuracy of our approximate approach, our model correctly predicts the neutron brightness at both temperatures.

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

    Science.gov (United States)

    Kother, L. K.; Hammer, M. D.; Finlay, C. C.; Olsen, N.

    2014-12-01

    We present a technique for modelling the lithospheric magnetic field based on estimation of equivalent potential field sources. As a first demonstration we present an application to magnetic field measurements made by the CHAMP satellite during the period 2009-2010. Three component vector field data are utilized at all latitudes. Estimates of core and large-scale magnetospheric sources are removed from the satellite measurements using the CHAOS-4 model. Quiet-time and night-side data selection criteria are also employed to minimize the influence of the ionospheric field. The model for the remaining lithospheric magnetic field consists of magnetic point sources (monopoles) arranged in an icosahedron grid with an increasing grid resolution towards the airborne survey area. The corresponding source values are estimated using an iteratively reweighted least squares algorithm that includes model regularization (either quadratic or maximum entropy) and Huber weighting. Data error covariance matrices are implemented, accounting for the dependence of data error variances on quasi-dipole latitudes. Results show good consistency with the CM5 and MF7 models for spherical harmonic degrees up to n = 95. Advantages of the equivalent source method include its local nature and the ease of transforming to spherical harmonics when needed. The method can also be applied in local, high resolution, investigations of the lithospheric magnetic field, for example where suitable aeromagnetic data is available. To illustrate this possibility, we present preliminary results from a case study combining satellite measurements and local airborne scalar magnetic measurements of the Norwegian coastline.

  17. A unified field theory II: Gravity interacting with a Yang-Mills and Higgs field

    CERN Document Server

    Gerhardt, Claus

    2016-01-01

    We quantize the interaction of gravity with a Yang-Mills and Higgs field using canonical quantization. Similar to the approach in a previous paper we discard the Wheeler-DeWitt equation and express the Hamilton constraint by the evolution equation of the mean curvature of the hypersurfaces in the foliation defined by the Hamiltonian setting. Expressing the time derivative of the mean curvature with the help of the Poisson brackets the canonical quantization of this equation leads to a wave equation in $Q=(0,\\infty)\\times \\cal{S}_o$, where $\\cal{S}_o$ is one of the Cauchy hypersurfaces in the Hamiltonian setting. The wave equation describes the interaction of an arbitrary Riemannian metric in $\\cal{S}_o$ and a given Yang-Mills and Higgs field. If the metric is complete $Q$ is globally hyperbolic. In case $\\cal{S}_o$ is compact we also prove a spectral resolution of the wave equation and establish sufficient conditions guaranteeing a mass gap.

  18. Transducer models in the ultrasound simulation program FIELD II and their accuracy

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Bæk, David

    2010-01-01

    The FIELD II simulation program can be used for simulating any kind of linear ultrasound fields. The program is capable of describing multi-element transducers used with any kind of excitation, apodization, and focusing. The program has been widely used in both academia and by commercial ultrasound...... companies for investigation novel transducer geometries and advanced linear imaging schemes. The program models transducer geometries using a division of the transducer elements into either rectangles, triangles, or bounding lines. The precision of the simulation and the simulation time is intimately linked...

  19. Influence of external resonant magnetic perturbation field on edge plasma of small tokamak HYBTOK-II

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Y., E-mail: hayashi-yuki13@ees.nagoya-u.ac.jp [Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Suzuki, Y.; Ohno, N. [Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Okamoto, M. [Ishikawa National College of Technology, Kitachujo, Tsubata-cho, Kahoku-gun, Ishikawa 929-0392 (Japan); Kikuchi, Y. [University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Sakakibara, S.; Watanabe, K.; Takemura, Y. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan)

    2015-08-15

    Radial profile of externally applied resonant magnetic perturbation (RMP) field with mode numbers of m = 6 and n = 2 in a small tokamak device HYBTOK-II have been investigated using a magnetic probe array, which is able to measure the radial profile of magnetic field perturbation induced by applying RMP. Results of RMP penetration into the plasma show that the RMP decreased toward the plasma center, while they were amplified around the resonant surface with a safety factor q = 3 due to the formation of magnetic islands. This suggests that RMP fields for controlling edge plasmas may trigger some kind of MHD instabilities. In addition, simulation results, based on a linearized four-field model, which agrees with the experimental ones, indicates that the penetration and amplification process of RMP strongly depend on a Doppler-shifted frequency between the RMP and plasma rotation.

  20. Constraining the Solar Coronal Magnetic Field Strength using Split-band Type II Radio Burst Observations

    Science.gov (United States)

    Kishore, P.; Ramesh, R.; Hariharan, K.; Kathiravan, C.; Gopalswamy, N.

    2016-11-01

    We report on low-frequency radio (85-35 MHz) spectral observations of four different type II radio bursts, which exhibited fundamental-harmonic emission and split-band structure. Each of the bursts was found to be closely associated with a whitelight coronal mass ejection (CME) close to the Sun. We estimated the coronal magnetic field strength from the split-band characteristics of the bursts, by assuming a model for the coronal electron density distribution. The choice of the model was constrained, based on the following criteria: (1) when the radio burst is observed simultaneously in the upper and lower bands of the fundamental component, the location of the plasma level corresponding to the frequency of the burst in the lower band should be consistent with the deprojected location of the leading edge (LE) of the associated CME; (2) the drift speed of the type II bursts derived from such a model should agree closely with the deprojected speed of the LE of the corresponding CMEs. With the above conditions, we find that: (1) the estimated field strengths are unique to each type II burst, and (2) the radial variation of the field strength in the different events indicate a pattern. It is steepest for the case where the heliocentric distance range over which the associated burst is observed is closest to the Sun, and vice versa.

  1. Depositional environment and source potential of Jurassic coal-bearing sediments (Gresten Formation, Hoflein gas/condensate field, Austria)

    Energy Technology Data Exchange (ETDEWEB)

    Sachsenhofer, R.F.; Bechtel, A.; Kuffner, T.; Rainer, T.; Gratzer, R.; Sauer, R.; Sperl, H. [Mount University of Leoben, Leoben (Austria)

    2006-05-15

    Coal-bearing Jurassic sediments (Gresten Formation; Lower Quartzarenite Member) are discussed as source rocks for gas and minor oil in the basement of the Alpine-Carpathian frontal zone (e.g. Hoflein gas/condensate field). Core material has therefore been analysed to characterize depositional environment and source potential of the Lower Quartzarenite Member (LQM). Geochemical data from the Hoflein condensate are used to establish a Source-condensate correlation. The LQM was deposited in a flood basin with transitions to a delta-plain environment. Coal originated in frequently flooded mires and evolved within an oxygenated and acidic environment. It is inferred from geochemical data that organic matter from aquatic macrophytes and gymnosperms contributed to coal formation. Wildfires were abundant and oxidation of plant remains occurred frequently. This resulted in the formation of dull coal with very high inertinite contents. Bituminous shales were formed in deeper waters under dysoxic conditions. Apart from abundant algae and micro-organisms, it is concluded that there was an increased contribution of higher land plants relative to macrophytes to the biomass of the shales. Despite high inertinite contents, coal within the LQM has a significant oil potential. Bituminous shales contain a Type III-II kerogen. According to pyrolysis-gas chromatography data, coal and shale generate a high wax paraffinic oil. The organic matter is immature to marginal mature (0.55% Rr). Bituminous shales are considered a potential source for the Hoflein condensate. Coal may be the source for gas and minor oil in the Klement Field, but is not the source for the condensate.

  2. Observations of the Hubble Deep Field with the Infrared Space Observatory; 4, Association of sources with Hubble Deep Field Galaxies

    CERN Document Server

    Mann, B M

    1997-01-01

    We discuss the identification of sources detected by ISO at 6.7 and 15 micron in the Hubble Deep Field (HDF) region. We conservatively associate ISO sources with objects in existing optical and near-infrared HDF catalogues using the likelihood ratio method, confirming these results (and, in one case, clarifying them) with independent visual searches. We find fifteen ISO sources to be reliably associated with bright [I(AB) < 23] galaxies in the HDF, and one with an I(AB)=19.9 star, while a further eleven are associated with objects in the Hubble Flanking Fields (ten galaxies and one star). Amongst optically bright HDF galaxies, ISO tends to detect luminous, star-forming galaxies at fairly high redshift and with disturbed morphologies, in preference to nearby ellipticals.

  3. The Effects of Primary Sources and Field Trip Experience on the Knowledge Retention of Multicultural Content

    Science.gov (United States)

    Farmer, James; Knapp, Doug; Benton, Gregory M.

    2007-01-01

    Although small in scope, this study attempted to analyze the impacts of primary sources and field trip experiences on multicultural education through first-hand narrative interviews, one year after the experience. In particular, it assessed the recollections of students who participated in a one-half-day field trip to George Washington Carver…

  4. Particle acceleration and magnetic field amplification in hotspots of FR II galaxies: The case study 4C74.26

    CERN Document Server

    Araudo, Anabella T; Blundell, Katherine M

    2016-01-01

    It has been suggested that relativistic shocks in extragalactic sources may accelerate the most energetic cosmic rays. However, recent theoretical advances indicating that relativistic shocks are probably unable to accelerate particles to energies much larger than a PeV cast doubt on this. In the present contribution we model the radio to X-ray emission in the southern hotspot of the quasar 4C74.26. The synchrotron radio emission is resolved near the shock with the MERLIN radio-interferometer, and the rapid decay of this emission behind the shock is interpreted as the decay of the downstream magnetic field as expected for small scale turbulence. If our result is confirmed by analyses of other radiogalaxies, it provides firm observational evidence that relativistic shocks at the termination region of powerful jets in FR II radiogalaxies do not accelerate ultra high energy cosmic rays.

  5. A sparse equivalent source method for near-field acoustic holography

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Xenaki, Angeliki; Gerstoft, Peter

    2017-01-01

    This study examines a near-field acoustic holography method consisting of a sparse formulation of the equivalent source method, based on the compressive sensing (CS) framework. The method, denoted Compressive–Equivalent Source Method (C-ESM), encourages spatially sparse solutions (based...... on the superposition of few waves) that are accurate when the acoustic sources are spatially localized. The importance of obtaining a non-redundant representation, i.e., a sensing matrix with low column coherence, and the inherent ill-conditioning of near-field reconstruction problems is addressed. Numerical...

  6. Anoxic and Oxic Oxidation of Rocks Containing Fe(II)Mg-Silicates and Fe(II)-Monosulfides as Source of Fe(III)-Minerals and Hydrogen. Geobiotropy.

    Science.gov (United States)

    Bassez, Marie-Paule

    2017-03-01

    In this article, anoxic and oxic hydrolyses of rocks containing Fe (II) Mg-silicates and Fe (II)-monosulfides are analyzed at 25 °C and 250-350 °C. A table of the products is drawn. It is shown that magnetite and hydrogen can be produced during low-temperature (25 °C) anoxic hydrolysis/oxidation of ferrous silicates and during high-temperature (250 °C) anoxic hydrolysis/oxidation of ferrous monosulfides. The high-T (350 °C) anoxic hydrolysis of ferrous silicates leads mainly to ferric oxides/hydroxides such as the hydroxide ferric trihydroxide, the oxide hydroxide goethite/lepidocrocite and the oxide hematite, and to Fe(III)-phyllosilicates. Magnetite is not a primary product. While the low-T (25 °C) anoxic hydrolysis of ferrous monosulfides leads to pyrite. Thermodynamic functions are calculated for elementary reactions of hydrolysis and carbonation of olivine and pyroxene and E-pH diagrams are analyzed. It is shown that the hydrolysis of the iron endmember is endothermic and can proceed within the exothermic hydrolysis of the magnesium endmember and also within the exothermic reactions of carbonations. The distinction between three products of the iron hydrolysis, magnetite, goethite and hematite is determined with E-pH diagrams. The hydrolysis/oxidation of the sulfides mackinawite/troilite/pyrrhotite is highly endothermic but can proceed within the heat produced by the exothermic hydrolyses and carbonations of ferromagnesian silicates and also by other sources such as magma, hydrothermal sources, impacts. These theoretical results are confirmed by the products observed in several related laboratory experiments. The case of radiolyzed water is studied. It is shown that magnetite and ferric oxides/hydroxides such as ferric trihydroxide, goethite/lepidocrocite and hematite are formed in oxic hydrolysis of ferromagnesian silicates at 25 °C and 350 °C. Oxic oxidation of ferrous monosulfides at 25 °C leads mainly to pyrite and ferric oxides/hydroxides such as

  7. Source Regions of the Type II Radio Burst Observed During a CME-CME Interaction on 2013 May 22

    CERN Document Server

    Gopalswamy, P Mäkelä N; Akiyama, S; Krupar, V

    2016-01-01

    We report on our study of radio source regions during the type II radio burst on 2013 May 22 based on direction finding (DF) analysis of the Wind/WAVES and STEREO/WAVES (SWAVES) radio observations at decameter-hectometric (DH) wavelengths. The type II emission showed an enhancement that coincided with interaction of two coronal mass ejections (CMEs) launched in sequence along closely spaced trajectories. The triangulation of the SWAVES source directions posited the ecliptic projections of the radio sources near the line connecting the Sun and the STEREO-A spacecraft. The WAVES and SWAVES source directions revealed shifts in the latitude of the radio source indicating that the spatial location of the dominant source of the type II emission varies during the CME-CME interaction. The WAVES source directions close to 1 MHz frequencies matched the location of the leading edge of the primary CME seen in the images of the LASCO/C3 coronagraph. This correspondence of spatial locations at both wavelengths confirms tha...

  8. Classical 5D fields generated by a uniformly accelerated point source

    CERN Document Server

    Aharonovich, I

    2009-01-01

    Gauge fields associated with the manifestly covariant dynamics of particles in $(3,1)$ spacetime are five-dimensional. In this paper we explore the old problem of fields generated by a source undergoing hyperbolic motion in this framework. The 5D fields are computed numerically using absolute time $\\tau$-retarded Green-functions, and qualitatively compared with Maxwell fields generated by the same motion. We find that although the zero mode of all fields coincides with the corresponding Maxwell problem, the non-zero mode should affect, through the Lorentz force, the observed motion of test particles.

  9. The Herschel-ATLAS Data Release 1 Paper II: Multi-wavelength counterparts to submillimetre sources

    CERN Document Server

    Bourne, N; Maddox, S J; Dye, S; Furlanetto, C; Hoyos, C; Smith, D J B; Eales, S; Smith, M W L; Valiante, E; Alpaslan, M; Andrae, E; Baldry, I K; Cluver, M E; Cooray, A; Driver, S P; Dunlop, J S; Grootes, M W; Ivison, R J; Jarrett, T H; Liske, J; Madore, B F; Popescu, C C; Robotham, A G; Rowlands, K; Seibert, M; Thompson, M A; Tuffs, R J; Viaene, S; Wright, A H

    2016-01-01

    This paper is the second in a pair of articles presenting data release 1 (DR1) of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS), the largest single open-time key project carried out with the Herschel Space Observatory. The H-ATLAS is a wide-area imaging survey carried out in five photometric bands at 100, 160, 250, 350 and 500$\\mu$m covering a total area of 600deg$^2$. In this paper we describe the identification of optical counterparts to submillimetre sources in DR1, comprising an area of 161 deg$^2$ over three equatorial fields of roughly 12$^\\circ$x4.5$^\\circ$ centred at 9$^h$, 12$^h$ and 14.5$^h$ respectively. Of all the H-ATLAS fields, the equatorial regions benefit from the greatest overlap with current multi-wavelength surveys spanning ultraviolet (UV) to mid-infrared regimes, as well as extensive spectroscopic coverage. We use a likelihood-ratio technique to identify SDSS counterparts at r<22.4 for 250-$\\mu$m-selected sources detected at $\\geq$ 4$\\sigma$ ($\\approx$28mJy). We fin...

  10. New 6 and 3-cm radio-continuum maps of the Small Magellanic Cloud - part II: Point source catalogue

    Directory of Open Access Journals (Sweden)

    Wong G.F.

    2012-01-01

    Full Text Available We present two new catalogues of radio-continuum sources in the field of the Small Magellanic Cloud (SMC. These catalogues contain sources found at 4800 MHz (λ=6cm and 8640 MHz (λ=3cm. Some 457 sources have been detected at 3cm with 601 sources at 6cm created from new high-sensitivity and resolution radio-continuum images of the SMC from Crawford et al. (2011.

  11. New 6 and 3-cm radio-continuum maps of the Small Magellanic Cloud: Part II - Point source catalogue

    CERN Document Server

    Wong, G F; Filipović, M D; De Horta, A Y; Tothill, N F H; Collier, J D; Drasković, D; Galvin, T J; Payne, J L

    2012-01-01

    We present two new catalogues of radio-continuum sources in the field of the Small Magellanic Cloud (SMC). These catalogues contain sources found at 4800 MHz (lambda=6 cm) and 8640 MHz (lambda=3 cm). Some 457 sources have been detected at 3 cm with 601 sources at 6 cm created from new high-sensitivity and resolution radio-continuum images of the SMC from Crawford et al. (2011).

  12. The HST/ACS Coma Cluster Survey. II. Data Description and Source Catalogs

    Science.gov (United States)

    Hammer, Derek; Kleijn, Gijs Verdoes; Hoyos, Carlos; Den Brok, Mark; Balcells, Marc; Ferguson, Henry C.; Goudfrooij, Paul; Carter, David; Guzman, Rafael; Peletier, Reynier F.; hide

    2010-01-01

    The Coma cluster, Abell 1656, was the target of a HST-ACS Treasury program designed for deep imaging in the F475W and F814W passbands. Although our survey was interrupted by the ACS instrument failure in early 2007, the partially-completed survey still covers approximately 50% of the core high density region in Coma. Observations were performed for twenty-five fields with a total coverage area of 274 aremin(sup 2), and extend over a wide range of cluster-centric radii (approximately 1.75 Mpe or 1 deg). The majority of the fields are located near the core region of Coma (19/25 pointings) with six additional fields in the south-west region of the cluster. In this paper we present SEXTRACTOR source catalogs generated from the processed images, including a detailed description of the methodology used for object detection and photometry, the subtraction of bright galaxies to measure faint underlying objects, and the use of simulations to assess the photometric accuracy and completeness of our catalogs. We also use simulations to perform aperture corrections for the SEXTRACTOR Kron magnitudes based only on the measured source flux and its half-light radius. We have performed photometry for 76,000 objects that consist of roughly equal numbers of extended galaxies and unresolved objects. Approximately two-thirds of all detections are brighter than F814W=26.5 mag (AB), which corresponds to the 10sigma, point-source detection limit. We estimate that Coma members are 5-10% of the source detections, including a large population of compact objects (primarily GCs, but also cEs and UCDs), and a wide variety of extended galaxies from cD galaxies to dwarf low surface brightness galaxies. The initial data release for the HST-ACS Coma Treasury program was made available to the public in August 2008. The images and catalogs described in this study relate to our second data release.

  13. Military jet noise source imaging using multisource statistically optimized near-field acoustical holography.

    Science.gov (United States)

    Wall, Alan T; Gee, Kent L; Neilsen, Tracianne B; McKinley, Richard L; James, Michael M

    2016-04-01

    The identification of acoustic sources is critical to targeted noise reduction efforts for jets on high-performance tactical aircraft. This paper describes the imaging of acoustic sources from a tactical jet using near-field acoustical holography techniques. The measurement consists of a series of scans over the hologram with a dense microphone array. Partial field decomposition methods are performed to generate coherent holograms. Numerical extrapolation of data beyond the measurement aperture mitigates artifacts near the aperture edges. A multisource equivalent wave model is used that includes the effects of the ground reflection on the measurement. Multisource statistically optimized near-field acoustical holography (M-SONAH) is used to reconstruct apparent source distributions between 20 and 1250 Hz at four engine powers. It is shown that M-SONAH produces accurate field reconstructions for both inward and outward propagation in the region spanned by the physical hologram measurement. Reconstructions across the set of engine powers and frequencies suggests that directivity depends mainly on estimated source location; sources farther downstream radiate at a higher angle relative to the inlet axis. At some frequencies and engine powers, reconstructed fields exhibit multiple radiation lobes originating from overlapped source regions, which is a phenomenon relatively recently reported for full-scale jets.

  14. Experimental Development of Low-emittance Field-emission Electron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Lueangaranwong, A. [Northern Illinois Univ., DeKalb, IL (United States). Northern Illinois Center for Accelerator & Detector Development; Buzzard, C. [Northern Illinois Univ., DeKalb, IL (United States); Divan, R. [Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials; Korampally, V. [Northern Illinois Univ., DeKalb, IL (United States); Piot, P. [Northern Illinois Univ., DeKalb, IL (United States). Northern Illinois Center for Accelerator & Detector Development; Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-10-10

    Field emission electron sources are capable of extreme brightness when excited by static or time-dependent electro- magnetic fields. We are currently developing a cathode test stand operating in DC mode with possibility to trigger the emission using ultra-short (~ 100-fs) laser pulses. This contribution describes the status of an experiment to investigate field-emission using cathodes under development at NIU in collaboration with the Argonne’s Center for Nanoscale Materials.

  15. Simulation of RF power and multi-cusp magnetic field requirement for H- ion sources

    Science.gov (United States)

    Pathak, Manish; Senecha, V. K.; Kumar, Rajnish; Ghodke, Dharmraj. V.

    2016-12-01

    A computer simulation study for multi-cusp RF based H- ion source has been carried out using energy and particle balance equation for inductively coupled uniformly dense plasma considering sheath formation near the boundary wall of the plasma chamber for RF ion source used as high current injector for 1 Gev H- Linac project for SNS applications. The average reaction rates for different reactions responsible for H- ion production and destruction have been considered in the simulation model. The RF power requirement for the caesium free H- ion source for a maximum possible H- ion beam current has been derived by evaluating the required current and RF voltage fed to the coil antenna using transformer model for Inductively Coupled Plasma (ICP). Different parameters of RF based H- ion source like excited hydrogen molecular density, H- ion density, RF voltage and current of RF antenna have been calculated through simulations in the presence and absence of multicusp magnetic field to distinctly observe the effect of multicusp field. The RF power evaluated for different H- ion current values have been compared with the experimental reported results showing reasonably good agreement considering the fact that some RF power will be reflected from the plasma medium. The results obtained have helped in understanding the optimum field strength and field free regions suitable for volume emission based H- ion sources. The compact RF ion source exhibits nearly 6 times better efficiency compare to large diameter ion source.

  16. On the angular distribution of cosmic rays from an individual source in a turbulent magnetic field

    CERN Document Server

    Harari, Diego; Roulet, Esteban

    2015-01-01

    We obtain the angular distribution of the cosmic rays reaching an observer from an individual source and after propagation through a turbulent magnetic field, for different ratios between the source distance and the diffusion length. We study both the high-energy quasi-rectilinear regime as well as the transition towards the diffusive regime at lower energies where the deflections become large. We consider the impact of energy losses, showing that they tend to enhance the anisotropy of the source at a given energy. We also discuss lensing effects, in particular those that could result from the regular galactic magnetic field component, and show that the effect of the turbulent extragalactic magnetic fields can smooth out the divergent magnification peaks that would result for point-like sources in the limit of no turbulent deflections.

  17. A compact source condition for modelling focused fields using the pseudospectral time-domain method.

    Science.gov (United States)

    Munro, Peter R T; Engelke, Daniel; Sampson, David D

    2014-03-10

    The pseudospectral time-domain (PSTD) method greatly extends the physical volume of biological tissue in which light scattering can be calculated, relative to the finite-difference time-domain (FDTD) method. We have developed an analogue of the total-field scattered-field source condition, as employed in FDTD, for introducing focussed illuminations into PSTD simulations. This new source condition requires knowledge of the incident field, and applies update equations, at a single plane in the PSTD grid. Numerical artifacts, usually associated with compact PSTD source conditions, are minimized by using a staggered grid. This source condition's similarity with that used by the FDTD suggests a way in which existing FDTD codes can be easily adapted to PSTD codes.

  18. Synthesis of Directional Sources Using Wave Field Synthesis, Possibilities, and Limitations

    Directory of Open Access Journals (Sweden)

    Corteel E

    2007-01-01

    Full Text Available The synthesis of directional sources using wave field synthesis is described. The proposed formulation relies on an ensemble of elementary directivity functions based on a subset of spherical harmonics. These can be combined to create and manipulate directivity characteristics of the synthesized virtual sources. The WFS formulation introduces artifacts in the synthesized sound field for both ideal and real loudspeakers. These artifacts can be partly compensated for using dedicated equalization techniques. A multichannel equalization technique is shown to provide accurate results thus enabling for the manipulation of directional sources with limited reconstruction artifacts. Applications of directional sources to the control of the direct sound field and the interaction with the listening room are discussed.

  19. Neuromagnetic fields accompanying unilateral and bilateral voluntary movements: topography and analysis of cortical sources.

    Science.gov (United States)

    Kristeva, R; Cheyne, D; Deecke, L

    1991-08-01

    Movement-related magnetic fields (MRMFs) accompanying left and right unilateral and bilateral finger flexions were studied in 6 right-handed subjects. Six different MRMF components occurring prior to, and during both unilateral and bilateral movements are described: a slow pre-movement readiness field (RF, 1-0.5 sec prior to movement onset); a motor field (MF) starting shortly before EMG onset; 3 separate "movement-evoked" fields following EMG onset (MEFI at 100 msec; MEFII at 225 msec; and MEFIII at 320 msec); and a "post-movement" field (PMF) following the movement itself. The bilateral topography of the RF and MF for both unilateral and bilateral movements suggested bilateral generators for both conditions. Least-squares fitting of equivalent current dipole sources also indicated bilateral sources for MF prior to both unilateral and bilateral movements with significantly greater strength of contralateral sources in the case of unilateral movements. Differences in pre-movement field patterns for left versus right unilateral movements indicated possible cerebral dominance effects as well. A single current dipole in the contralateral sensorimotor cortex could account for the MEFI for unilateral movements and bilateral sensorimotor sources for bilateral movements. Other MRMF components following EMG onset indicated similar sources in sensorimotor cortex related to sensory feedback or internal monitoring of the movement. The results are discussed with respect to the possible generators active in sensorimotor cortex during unilateral and bilateral movement preparation and execution and their significance for the study of cortical organization of voluntary movement.

  20. The alkaline aluminium/hydrogen peroxide power source in the Hugin II unmanned underwater vehicle

    Science.gov (United States)

    Hasvold, Øistein; Johansen, Kjell Håvard; Mollestad, Ole; Forseth, Sissel; Størkersen, Nils

    In 1993, The Norwegian Defence Research Establishment (FFI) demonstrated AUV-Demo, an unmanned (untethered) underwater vehicle (UUV), powered by a magnesium/dissolved oxygen seawater battery (SWB). This technology showed that an underwater range of at least 1000 nautical miles at a speed of 4 knots was possible, but also that the maximum hotel load this battery system could support was very limited. Most applications for UUV technology need more power over a shorter period of time. Seabed mapping using a multibeam echo sounder mounted on an UUV was identified as a viable application and the Hugin project was started in 1995 in cooperation with Norwegian industry. For this application, an endurance of 36 h at 4 knots was required. Development of the UUV hull and electronics system resulted in the UUV Hugin I. It carries a Ni/Cd battery of 3 kW h, allowing up to 6 h under-water endurance. In parallel, we developed a battery based on a combination of alkaline Al/air and SWB technology, using a circulating alkaline electrolyte, aluminium anodes and maintaining the oxidant concentration in the electrolyte by continuously adding hydrogen peroxide (HP) to the electrolyte. This concept resulted in a safe battery, working at ambient pressure (balanced) and with sufficient power and energy density to allow the UUV Hugin II to make a number of successive dives, each of up to 36 h duration and with only 1 h deck time between dives for HP refill and electrolyte exchange. After 100 h, an exchange of anodes takes place. The power source consists of a four-cell Al/HP battery, a DC/DC converter delivering 600 W at 30 V, circulation and dosing pumps and a battery control unit. Hugin II is now in routine use by the Norwegian Underwater Intervention AS (NUI) which operates the UUV for high-precision seabed mapping down to a water depth of 600 m.

  1. The alkaline aluminium/hydrogen peroxide power source in the Hugin II unmanned underwater vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Hasvold, Oe.; Johansen, K.H.; Mollestad, O.; Forseth, S.; Stoerkersen, N. [Forsvarets Forskningsinstitutt, Kjeller (Norway)

    1999-07-01

    In 1993, the Norwegian Defence Research Establishment (FFI) demonstrated AUV-Demo, an unmanned (untethered) underwater vehicle (UUV), powered by a magnesium/dissolved oxygen seawater battery (SWB). This technology showed that an underwater range of at least 1000 nautical miles at a speed of 4 knots was possible, but also that the maximum hotel load this battery system could support was very limited. Most applications for UUV technology need more power over a shorter period of time. Seabed mapping using a multibeam echo sounder mounted on a UUV was identified as a viable application and the Hugin project was started in 1995 in cooperation with Norwegian industry. For this application, an endurance of 36 h at 4 knots was required. Development of the UUV hull and electronics system resulted in the UUV Hugin I. It carries a Ni/Cd battery of 3 kW h, allowing up to 6 h under-water endurance. In parallel, we developed a battery based on a combination of alkaline Al/air and SWB technology, using a circulating alkaline electrolyte, aluminium anodes and maintaining the oxidant concentration in the electrolyte by continuously adding hydrogen peroxide (HP) to the electrolyte. This concept resulted in a safe battery, working at ambient pressure (balanced) and with sufficient power and energy density to allow the UUV Hugin II to make a number of successive dives, each of up to 36 h duration and with only 1 h deck time between dives for HP refill and electrolyte exchange. After 100 h, an exchange of anodes takes place. The power source consists of a four-cell Al/HP battery, a DC/DC converter delivering 600 W at 30 V, circulation and dosing pumps and a battery control unit. Hugin II is now in routine use by the Norwegian Underwater Intervention AS (NUI) which operates the UUV for high-precision seabed mapping down to a water depth of 600 m. (orig.)

  2. Shielding NSLS-II light source: Importance of geometry for calculating radiation levels from beam losses

    Science.gov (United States)

    Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.; Wahl, W.

    2016-11-01

    Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and ramped operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (Designing supplemental shielding near the loss point using the analytic shielding model is shown to be inadequate because of its lack of geometry specification for the EM shower process. To predict the dose rates outside the tunnel requires detailed description of the geometry and materials that the beam losses will encounter inside the tunnel. Modern radiation shielding Monte-Carlo codes, like FLUKA, can handle this geometric description of the radiation transport process in sufficient detail, allowing accurate predictions of the dose rates expected and the ability to show weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. This made the effective shielding process for NSLS-II quite accurate and reliable. The principles used to provide supplemental shielding to the NSLS-II accelerators and the lessons learned from this process are presented.

  3. Chemical Ionization Mass Spectrometry Using Carbon Nanotube Field Emission Electron Sources

    Science.gov (United States)

    Radauscher, Erich J.; Keil, Adam D.; Wells, Mitch; Amsden, Jason J.; Piascik, Jeffrey R.; Parker, Charles B.; Stoner, Brian R.; Glass, Jeffrey T.

    2015-11-01

    A novel chemical ionization (CI) source has been developed based on a carbon nanotube (CNT) field emission electron source. The CNT-based electron source was evaluated and compared with a standard filament thermionic electron source in a commercial explosives trace detection desktop mass spectrometer. This work demonstrates the first reported use of a CNT-based ion source capable of collecting CI mass spectra. Both positive and negative modes were investigated. Spectra were collected for a standard mass spectrometer calibration compound, perfluorotributylamine (PFTBA), as well as trace explosives including trinitrotoluene (TNT), Research Department explosive (RDX), and pentaerythritol tetranitrate (PETN). The electrical characteristics, lifetime at operating pressure, and power requirements of the CNT-based electron source are reported. The CNT field emission electron sources demonstrated an average lifetime of 320 h when operated in constant emission mode under elevated CI pressures. The ability of the CNT field emission source to cycle on and off can provide enhanced lifetime and reduced power consumption without sacrificing performance and detection capabilities.

  4. Concepts of magnetic filter fields in powerful negative ion sources for fusion

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, W., E-mail: kraus@ipp.mpg.de; Fantz, U.; Heinemann, B.; Wünderlich, D. [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany)

    2016-02-15

    The performance of large negative ion sources used in neutral beam injection systems is in long pulses mainly determined by the increase of the currents of co-extracted electrons. This is in particular a problem in deuterium and limits the ion currents which are for long pulses below the requirements for the ITER source. In the source of the ELISE test facility, the magnetic field in front of the first grid, which is essential to reduce the electron current, is generated by a current of several kA flowing through the plasma facing grid. Weakening of this field by the addition of permanent magnets placed close to the lateral walls has led to a reduction of the electron current by a factor three without loss of ion current when source was operated in volume production. If this effect can be validated for the cesiated source, it would be a large step towards achieving the ITER parameter in long pulses.

  5. Variable Stars in the Field of the Hydra II Ultra-faint Dwarf Galaxy

    Science.gov (United States)

    Vivas, A. Katherina; Olsen, Knut; Blum, Robert; Nidever, David L.; Walker, Alistair R.; Martin, Nicolas F.; Besla, Gurtina; Gallart, Carme; van der Marel, Roeland P.; Majewski, Steven R.; Kaleida, Catherine C.; Muñoz, Ricardo R.; Saha, Abhijit; Conn, Blair C.; Jin, Shoko

    2016-05-01

    We report the discovery of one RR Lyrae star in the ultra-faint satellite galaxy Hydra II based on time series photometry in the g, r and i bands obtained with the Dark Energy Camera at Cerro Tololo Inter-American Observatory, Chile. The association of the RR Lyrae star discovered here with Hydra II is clear because is located at 42\\prime\\prime from the center of the dwarf, well within its half-light radius of 102\\prime\\prime . The RR Lyrae star has a mean magnitude of i=21.30+/- 0.04 which is too faint to be a field halo star. This magnitude translates to a heliocentric distance of 151 ± 8 kpc for Hydra II; this value is ∼ 13% larger than the estimate from the discovery paper based on the average magnitude of several blue horizontal branch star candidates. The new distance implies a slightly larger half-light radius of {76}-10+12 pc and a brighter absolute magnitude of {M}V=-5.1+/- 0.3, which keeps this object within the realm of the dwarf galaxies. A comparison with other RR Lyrae stars in ultra-faint systems indicates similar pulsational properties among them, which are different to those found among halo field stars and those in the largest of the Milky Way satellites. We also report the discovery of 31 additional short period variables in the field of view (RR Lyrae, SX Phe, eclipsing binaries, and a likely anomalous cepheid) which are likely not related with Hydra II.

  6. Source term derivation and radiological safety analysis for the TRICO II research reactor in Kinshasa

    Energy Technology Data Exchange (ETDEWEB)

    Muswema, J.L., E-mail: jeremie.muswem@unikin.ac.cd [Faculty of Science, University of Kinshasa, P.O. Box 190, KIN XI (Congo, The Democratic Republic of the); Ekoko, G.B. [Faculty of Science, University of Kinshasa, P.O. Box 190, KIN XI (Congo, The Democratic Republic of the); Lukanda, V.M. [Faculty of Science, University of Kinshasa, P.O. Box 190, KIN XI (Congo, The Democratic Republic of the); Democratic Republic of the Congo' s General Atomic Energy Commission, P.O. Box AE1 (Congo, The Democratic Republic of the); Lobo, J.K.-K. [Faculty of Science, University of Kinshasa, P.O. Box 190, KIN XI (Congo, The Democratic Republic of the); Darko, E.O. [Radiation Protection Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana); Boafo, E.K. [University of Ontario Institute of Technology, 2000 Simcoe St. North, Oshawa, ONL1 H7K4 (Canada)

    2015-01-15

    Highlights: • Atmospheric dispersion modeling for two credible accidents of the TRIGA Mark II research reactor in Kinshasa (TRICO II) was performed. • Radiological safety analysis after the postulated initiating events (PIE) was also carried out. • The Karlsruhe KORIGEN and the HotSpot Health Physics codes were used to achieve the objectives of this study. • All the values of effective dose obtained following the accident scenarios were below the regulatory limits for reactor staff members and the public, respectively. - Abstract: The source term from the 1 MW TRIGA Mark II research reactor core of the Democratic Republic of the Congo was derived in this study. An atmospheric dispersion modeling followed by radiation dose calculation were performed based on two possible postulated accident scenarios. This derivation was made from an inventory of peak radioisotope activities released in the core by using the Karlsruhe version of isotope generation code KORIGEN. The atmospheric dispersion modeling was performed with HotSpot code, and its application yielded to radiation dose profile around the site using meteorological parameters specific to the area under study. The two accident scenarios were picked from possible accident analyses for TRIGA and TRIGA-fueled reactors, involving the case of destruction of the fuel element with highest activity release and a plane crash on the reactor building as the worst case scenario. Deterministic effects of these scenarios are used to update the Safety Analysis Report (SAR) of the reactor, and for its current version, these scenarios are not yet incorporated. Site-specific meteorological conditions were collected from two meteorological stations: one installed within the Atomic Energy Commission and another at the National Meteorological Agency (METTELSAT), which is not far from the site. Results show that in both accident scenarios, radiation doses remain within the limits, far below the recommended maximum effective

  7. An equivalent source method for modelling the global lithospheric magnetic field

    Science.gov (United States)

    Kother, Livia; Hammer, Magnus D.; Finlay, Christopher C.; Olsen, Nils

    2015-10-01

    We present a new technique for modelling the global lithospheric magnetic field at Earth's surface based on the estimation of equivalent potential field sources. As a demonstration we show an application to magnetic field measurements made by the CHAMP satellite during the period 2009-2010 when it was at its lowest altitude and solar activity was quiet. All three components of the vector field data are utilized at all available latitudes. Estimates of core and large-scale magnetospheric sources are removed from the measurements using the CHAOS-4 model. Quiet-time and night-side data selection criteria are also employed to minimize the influence of the ionospheric field. The model for the remaining lithospheric magnetic field consists of magnetic equivalent potential field sources (monopoles) arranged in an icosahedron grid at a depth of 100 km below the surface. The corresponding model parameters are estimated using an iteratively reweighted least-squares algorithm that includes model regularization (either quadratic or maximum entropy) and Huber weighting. Data error covariance matrices are implemented, accounting for the dependence of data variances on quasi-dipole latitude. The resulting equivalent source lithospheric field models show a degree correlation to MF7 greater than 0.7 out to spherical harmonic degree 100. Compared to the quadratic regularization approach, the entropy regularized model possesses notably lower power above degree 70 and a lower number of degrees of freedom despite fitting the observations to a very similar level. Advantages of our equivalent source method include its local nature, the possibility for regional grid refinement and the production of local power spectra, the ability to implement constraints and regularization depending on geographical position, and the ease of transforming the equivalent source values into spherical harmonics.

  8. Newton's 2nd Law, Radiation Reaction & Type II Einstein-Maxwell Fields

    CERN Document Server

    Newman, Ezra T

    2011-01-01

    Considering perturbations off the Reissner-Nordstrom metric while keeping the perturbations in the class of type II Einstein-Maxwell metrics, we do a spherical harmonic expansion of all the variables up to the quadrupole term. This leads to a rather surprising results. Referring to the source of the metric as a type II particle (analogous to referring to a Schwarzschild-Reissner-Nordstrom or Kerr-Newman particle), we see immediately that the Bondi momentum of the particle take the classical form of mass times velocity plus an electromagnetic radiation reaction term while the Bondi mass loss equation become the classical gravitational and electromagnetic (electric and magnetic) dipole and quadrupole radiation. The Bondi momentum loss equation turns into Newtons second law of motion containing the Abraham, Lorentz, Dirac radiation reaction force plus a momentum recoil (rocket) force while the reality condition on the Bondi mass aspect yields the conservation of angular momentum.

  9. An ion species model for positive ion sources - part II analysis of hydrogen isotope effects

    CERN Document Server

    Surrey, E

    2014-01-01

    A one dimensional model of the magnetic multipole volume plasma source has been developed for application to intense ion/neutral atom beam injectors. The model uses plasma transport coefficients for particle and energy flow to create a detailed description of the plasma parameters along an axis parallel to that of the extracted beam. In this paper the isotopic modelling of positive hydrogenic ions is considered and compared with experimental data from the neutral beam injectors of the Joint European Torus. The use of the code to gain insights into the processes contributing to the ratios of the ionic species is demonstrated and the conclusion is drawn that 75% of the atomic ion species arises from ionization of dissociated molecules and 25% from dissociation of the molecular ions. However whilst the former process is independent of the filter field, the latter is sensitive to the change in distribution of fast and thermal electrons produced by the magnetic filter field and an optimum combination of field stre...

  10. Self-consistent evolution of gas and cosmic rays in Cygnus A and similar FR II classic double radio sources

    CERN Document Server

    Mathews, William G

    2010-01-01

    In Cygnus A and other classical FR II double radio sources, powerful opposing jets from the cores of halo-centered galaxies drive out into the surrounding cluster gas, forming hotspots of shocked and compressed cluster gas at the jet extremities. The moving hotspots are sandwiched between two shocks. An inner-facing shock receives momentum and cosmic rays from the jet and creates additional cosmic rays that form a radio lobe elongated along the jet axis. An outer-facing bow shock moves directly into the undisturbed group or cluster gas, creating a cocoon of shocked gas enclosing the radio lobe. We describe computations that follow the self-consistent dynamical evolution of the shocked cluster gas and the relativistic synchrotron-emitting gas inside the lobes. Relativistic and non-relativistic components exchange momentum by interacting with small magnetic fields having dynamically negligible energy densities. The evolution of Cygnus A is governed almost entirely by cosmic ray energy flowing from the hotspots....

  11. An Angular Overlap Model for Cu(II) Ion in the AMOEBA Polarizable Force Field.

    Science.gov (United States)

    Xiang, Jin Yu; Ponder, Jay W

    2014-01-01

    An extensible polarizable force field for transition metal ion was developed based on AMOEBA and the angular overlap model (AOM) with consistent treatment of electrostatics for all atoms. Parameters were obtained by fitting molecular mechanics (MM) energies to various ab initio gas-phase calculations. The results of parameterization were presented for copper (II) ion ligated to water and model fragments of amino acid residues involved in the copper binding sites of type 1 copper proteins. Molecular dynamics (MD) simulations were performed on aqueous copper (II) ion at various temperatures, as well as plastocyanin (1AG6) and azurin (1DYZ). Results demonstrated that the AMOEBA-AOM significantly improves the accuracy of classical MM in a number of test cases when compared to ab initio calculations. The Jahn-Teller distortion for hexa-aqua copper (II) complex was handled automatically without specifically designating axial and in-plane ligands. Analyses of MD trajectories resulted in a 6-coordination first solvation shell for aqueous copper (II) ion and a 1.8ns average residence time of water molecules. The ensemble average geometries of 1AG6 and 1DYZ copper binding sites were in general agreement with X-ray and previous computational studies.

  12. Magnetic field structure of IC 63 and IC 59 associated with H II region Sh 185

    Science.gov (United States)

    Soam, A.; Maheswar, G.; Lee, Chang Won; Neha, S.; Andersson, B.-G.

    2017-02-01

    Bright-rimmed clouds (BRCs) are formed at the periphery of H II regions as the radiation from the central star interacts with dense gas. The ionization and resulting compression of the clouds may lead to cloud disruption causing secondary star formation depending on the stellar and gas parameters. Here we use R-band polarimetry to probe the plane-of-the sky magnetic field for two nearby BRCs, IC 59 and IC 63. Both nebulae are illuminated by γ Cas with the direction of the ionizing radiation being orientated parallel or perpendicular to the local magnetic field, allowing us to probe the importance of magnetic field pressure in the evolution of BRCs. Because of the proximity of the system (˜200 pc), we have acquired a substantial sample of over 500 polarization measurements for stars that form the background to the nebulae. On large scales, the magnetic field geometries of both clouds are anchored to the ambient magnetic field. For IC 63, the magnetic field is aligned parallel to the head-tail morphology of the main condensation, with a convex morphology relative to the direction of the ionizing radiation. We estimate the plane-of-the-sky magnetic field strength in IC 63 to be ˜ 90 μG. In IC 59, the projected magnetic field follows the M-shape morphology of the cloud. Here, field lines present a concave shape with respect to the direction of the ionizing radiation from γ Cas. Comparing our observations to published theoretical models, we find good general agreement, supporting the importance of magnetic fields in BRC evolution.

  13. Passive Lossless Huygens Metasurfaces for Conversion of Arbitrary Source Field to Directive Radiation

    CERN Document Server

    Epstein, Ariel

    2014-01-01

    We present a semi-analytical formulation of the interaction between a given source field and a scalar Huygens metasurface (HMS), a recently introduced promising concept for wavefront manipulation based on a sheet of orthogonal electric and magnetic dipoles. Utilizing the equivalent surface impedance representation of these metasurfaces, we establish that an arbitrary source field can be converted into directive radiation via a passive lossless HMS if two physical conditions are met: local power conservation and local impedance equalization. Expressing the fields via their plane-wave spectrum and harnessing the slowly-varying envelope approximation we obtain semi-analytical formulae for the scattered fields, and prescribe the surface reactance required for the metasurface implementation. The resultant design procedure indicates that the local impedance equalization induces a Fresnel-like reflection, while local power conservation forms a radiating virtual aperture which follows the total excitation field magni...

  14. Effect of axial magnetic field on a 2.45 GHz permanent magnet ECR ion source

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, T., E-mail: tsubasa@oshima-k.ac.jp; Wada, H.; Furuse, M. [National Institute of Technology, Oshima College, 1091-1 Komatsu, Suouoshima, Oshima, Yamaguchi 742-2193 (Japan); Asaji, T. [National Institute of Technology, Toyama College, 13 Hongo, Toyama 939-8630 (Japan)

    2016-02-15

    Herein, we conduct a fundamental study to improve the generation efficiency of a multi-charged ion source using argon. A magnetic field of our electron cyclotron resonance ion source is composed of a permanent magnet and a solenoid coil. Thereby, the axial magnetic field in the chamber can be tuned. Using the solenoid coil, we varied the magnetic field strength in the plasma chamber and measured the ion beam current extracted at the electrode. We observed an approximately three times increase in the Ar{sup 4+} ion beam current when the magnetic field on the extractor-electrode side of the chamber was weakened. From our results, we can confirm that the multi-charged ion beam current changes depending on magnetic field intensity in the plasma chamber.

  15. Classical Electromagnetic Fields from Quantum Sources in Heavy-Ion Collisions

    CERN Document Server

    Holliday, Robert

    2016-01-01

    Electromagnetic fields are generated in high energy nuclear collisions by spectator valence protons. These fields are traditionally computed by integrating the Maxwell equations with point sources. One might expect that such an approach is valid at distances much larger than the proton size and thus such a classical approach should work well for almost the entire interaction region in the case of heavy nuclei. We argue that, in fact, the contrary is true: due to the quantum diffusion of the proton wave function, the classical approximation breaks down at distances of the order of the system size. As a result, the electromagnetic field (in vacuum) is present in the interaction region in the form of a traveling wave for much longer time than it was previously anticipated. Additionally, the quantum treatment of the sources removes the short-distance divergence of the field, making it possible to compute the maximal field strength achievable at a given collision energy.

  16. Source rock evaluation and organic geochemistry of Belayim Marine Oil Field, Gulf of Suez, Egypt

    Directory of Open Access Journals (Sweden)

    Mohamed Abu Al-Atta

    2014-09-01

    In general, TOC analyses showed that the Nubia-A and B formation sediments are fairly immature compared to good source rocks with very high Hydrogen Index indicative of kerogen type II. The geochemical investigations of two oil samples indicate that the Upper Rudeis oil of Belayim Marine was derived from a marine carbonate rich source, which is relatively rich in algal organic matter and has moderate sulfur content. The maturity of the analyzed oils (about 0.75% R0 falls short from the stage of peak hydrocarbon generation which is known to be reached at about 0.85% R0.

  17. Plasma expansion across a transverse magnetic field in a negative hydrogen ion source for fusion

    Science.gov (United States)

    Fantz, U.; Schiesko, L.; Wünderlich, D.

    2014-08-01

    High power negative hydrogen ion sources operating at 0.3 Pa are a key component of the neutral beam injection systems for the international fusion experiment ITER. To achieve the required large ion current at a tolerable number of co-extracted electrons the source is equipped with a magnetic filter field (up to 10 mT). The IPP prototype source (1/8 of the area of the ITER source) has been equipped with a flexible magnetic filter frame to perform filter field studies (position, polarity, strength). Axial profiles of the plasma parameters are measured with two Langmuir probes, positioned in the upper and the lower half of the expansion chamber. In addition to the expected decrease in electron temperature and density a vertical drift develops the direction depending on the polarity of the field. Without field no drift is observed. The drift is less pronounced in caesium seeded discharges and almost vanishes in deuterium, indicating an influence of the ion mass on the drift. A comparison with results from a half-size ITER source reveals that the plasma is much more uniform in the large source.

  18. The SRP-II as a Rich Source of Data on the Psychopathic Personality

    Science.gov (United States)

    Lester, Whitney S.; Salekin, Randall T.; Sellbom, Martin

    2013-01-01

    This study examined the factor structure, external correlates, and predictive utility of the Self-Report Psychopathy scale (SRP-II; Hare, Harpur, & Hemphill, 1989). Despite a revision of the SRP-II to address, among other criticisms, a lack of items reflecting antisocial behavior, we hypothesized that the SRP-II would have a conceptually coherent…

  19. Aspects of ultra-cold neutron production in radiation fields at the FRM II

    Energy Technology Data Exchange (ETDEWEB)

    Wlokka, Stephan Albrecht

    2016-08-17

    Neutrons are called ''ultra-cold'', if they are reflected by a material surface under all angles of incident. They can then be stored for long times (ca. 1000s). In the new UCN source at the FRM II, Deuterium will be used to produce the UCN. Its behaviour under irradiation was investigated. Additionally the transport properties of new UCN guides were tested. Also, the helium-3 content of purified helium samples was examined, because using this type of helium greatly reduces the tritium production when used at the reactor.

  20. The ROSAT deep survey; 5, X-rays Sources and Optical Identifications in the Marano Field

    CERN Document Server

    Zamorani, G; Hasinger, G; Burg, R; Giacconi, R; Schmidt, M; Trümper, J E; Ciliegi, P; Gruppioni, C; Marano, B

    1999-01-01

    We present the X-ray data and the optical identifications for a deep ROSAT PSPC observation in the "Marano field". In the inner region of the ROSAT field (15' radius) we detected 50 X-ray sources with Sx >= 3.7x10^(-15) erg/cm^2/s. When corrected for the different sensitivity over the field, the estimated observed surface density at Sx >= 4x10^(-15) erg/cm^2/s is 272+/-40 sources/sq.deg. Four X-ray sources, corresponding to 8% of the total sample, have been detected in radio images with a flux limit of about 0.2 mJy. Careful statistical analysis of multicolour CCD data in the error boxes of the 50 X-ray sources has led to the identification of 42 sources, corresponding to 84% of the X-ray sample. These 42 reliable identifications are 33 AGNs (including two radio galaxies and one BL Lac candidate; 79% of the identified sources), 2 galaxies, 3 groups or clusters of galaxies and 4 stars. We also show that it is likely that a few of the 8 unidentified sources are such because the derived X-ray positions may be of...

  1. Developments in Polarization and Energy Control of APPLE-II Undulators at Diamond Light Source

    Science.gov (United States)

    Longhi, E. C.; Bencok, P.; Dobrynin, A.; Rial, E. C. M.; Rose, A.; Steadman, P.; Thompson, C.; Thomson, A.; Wang, H.

    2013-03-01

    A pair of 2m long APPLE-II type undulators have been built for the I10 BLADE beamline at Diamond Light Source. These 48mm period devices have gap as well as four moveable phase axes which provide the possibility to produce the full range of elliptical polarizations as well as linear polarization tilted through a full 180deg. The mechanical layout chosen has a 'master and slave' arrangement of the phase axes on the top and bottom. This arrangement allows the use of symmetries to provide operational ease for both changing energy using only the master phase while keeping fixed linear horizontal or circular polarization, as well as changing linear polarization angle while keeping fixed energy [1]. The design allows very fast motion of the master phase arrays, without sacrifice of accuracy, allowing the possibility of mechanical polarization switching at 1Hz for dichroism experiments. We present the mechanical design features of these devices, as well as the results of magnetic measurements and shimming from before installation. Finally, we present the results of characterization of these devices by the beamline, including polarimetry, which has been done on the various modes of motion to control energy and polarization. These modes of operation have been available to users since 2011.

  2. Highly Parallel Demagnetization Field Calculation Using the Fast Multipole Method on Tetrahedral Meshes with Continuous Sources

    CERN Document Server

    Palmesi, Pietro; Bruckner, Florian; Abert, Claas; Suess, Dieter

    2016-01-01

    The long-range magnetic field is the most time-consuming part in micromagnetic simulations. Improvements both on a numerical and computational basis can relief problems related to this bottleneck. This work presents an efficient implementation of the Fast Multipole Method [FMM] for the magnetic scalar potential as used in micromagnetics. We assume linearly magnetized tetrahedral sources, treat the near field directly and use analytical integration on the multipole expansion in the far field. This approach tackles important issues like the vectorial and continuous nature of the magnetic field. By using FMM the calculations scale linearly in time and memory.

  3. Measurement of coherence length and incoherent source size of hard x-ray undulator beamline at Pohang Light Source-II

    Energy Technology Data Exchange (ETDEWEB)

    Park, So Yeong; Hong, Chung Ki [Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of); Lim, Jun, E-mail: limjun@postech.ac.kr [Pohang Accelerator Laboratory, POSTECH, Pohang 790-784 (Korea, Republic of)

    2014-04-15

    We measured the spatial coherence length and incoherent source size of a hard x-ray undulator beamline at Pohang Light Source-II, the stored electron energy of which has been increased from 2.5 GeV to 3 GeV. The coherence length was determined by single-slit measurement of the visibility of the Fresnel diffraction pattern. The correlated incoherent source size was cross-checked for three different optics: the single slit, beryllium parabolic compound refractive lenses, and the Fresnel zone plate. We concluded that the undulator beamline has an effective incoherent source size (FWHM) of 540 μm (horizontal) × 50 μm (vertical)

  4. Measurement of coherence length and incoherent source size of hard x-ray undulator beamline at Pohang Light Source-II.

    Science.gov (United States)

    Park, So Yeong; Hong, Chung Ki; Lim, Jun

    2014-04-01

    We measured the spatial coherence length and incoherent source size of a hard x-ray undulator beamline at Pohang Light Source-II, the stored electron energy of which has been increased from 2.5 GeV to 3 GeV. The coherence length was determined by single-slit measurement of the visibility of the Fresnel diffraction pattern. The correlated incoherent source size was cross-checked for three different optics: the single slit, beryllium parabolic compound refractive lenses, and the Fresnel zone plate. We concluded that the undulator beamline has an effective incoherent source size (FWHM) of 540 μm (horizontal) × 50 μm (vertical).

  5. Magnetic field structure of IC 63 and IC 59 associated to H II region - Sh 185

    CERN Document Server

    Soam, A; Lee, Chang Won; Neha, S; Andersson, B-G

    2016-01-01

    Bright-rimmed clouds (BRCs) are formed at the periphery of H$~$II regions as the radiation from the central star interacts with dense gas. The ionization and resulting compression of the clouds may lead to cloud disruption causing secondary star formation depending on the stellar and gas parameters. Here we use R-band polarimetry to probe the plane-of-the sky magnetic field in the two near-by BRCs IC\\,59 and IC\\,63. Both nebulae are illuminated by $\\gamma$ Cas with the direction of ionizing radiation being orientated parallel or perpendicular to the local magnetic field, allowing us to probe the importance of magnetic field pressure in the evolution of BRCs. Because of the proximity of the system ($\\sim$200pc) we have acquired a substantial sample of over 500 polarization measurements for stars background to the nebulae. On large scales, the magnetic field geometries of both clouds are anchored to the ambient magnetic field. For IC 63, the magnetic field is aligned parallel to the head-tail morphology of the ...

  6. Spectra of faint sources in crowded fields with FRODOSpec on the Liverpool Robotic Telescope

    CERN Document Server

    Shalyapin, Vyacheslav N

    2014-01-01

    We check the performance of the FRODOSpec integral-field spectrograph for observations of faint sources in crowded fields. Although the standard processing pipeline L2 yields too noisy fibre spectra, we present a new processing software (L2LENS) that gives rise to accurate spectra for the two images of the gravitationally lensed quasar Q0957+561. Among other things, this L2LENS reduction tool accounts for the presence of cosmic-ray events, scattered-light backgrounds, blended sources, and chromatic source displacements due to differential atmospheric refraction. Our non-standard reduction of Q0957+561 data shows the ability of FRODOSpec to provide useful information on a wide variety of targets, and thus, the big potential of integral-field spectrographs on current and future robotic telescopes.

  7. Near- and Far-field Response to Compact Acoustic Sources in Stratified Convection Zones

    Science.gov (United States)

    Cally, Paul S.

    2013-05-01

    The role of the acoustic continuum associated with compact sources in the Sun's interior wave field is explored for a simple polytropic model. The continuum produces a near-field acoustic structure—the so-called acoustic jacket—that cannot be represented by a superposition of discrete normal modes. Particular attention is paid to monochromatic point sources of various frequency and depth, and to the surface velocity power that results, both in the discrete f- and p-mode spectrum and in the continuum. It is shown that a major effect of the continuum is to heal the surface wave field produced by compact sources, and therefore to hide them from view. It is found that the continuous spectrum is not a significant contributor to observable inter-ridge seismic power.

  8. Near- and Far-Field Response to Compact Acoustic Sources in Stratified Convection Zones

    CERN Document Server

    Cally, Paul S

    2013-01-01

    The role of the acoustic continuum associated with compact sources in the Sun's interior wave field is explored for a simple polytropic model. The continuum produces a near-field acoustic structure -- the so-called `acoustic jacket' -- that cannot be represented by a superposition of discrete normal modes. Particular attention is paid to monochromatic point sources of various frequency and depth, and to the surface velocity power that results, both in the discrete f- and p-mode spectrum and in the continuum. It is shown that a major effect of the continuum is to heal the surface wave field produced by compact sources, and therefore to hide them from view. It is found that the continuous spectrum is not a significant contributor to observable inter-ridge seismic power.

  9. NEAR- AND FAR-FIELD RESPONSE TO COMPACT ACOUSTIC SOURCES IN STRATIFIED CONVECTION ZONES

    Energy Technology Data Exchange (ETDEWEB)

    Cally, Paul S., E-mail: paul.cally@monash.edu [Monash Centre for Astrophysics and School of Mathematical Sciences, Monash University, Clayton, Victoria 3800 (Australia)

    2013-05-01

    The role of the acoustic continuum associated with compact sources in the Sun's interior wave field is explored for a simple polytropic model. The continuum produces a near-field acoustic structure-the so-called acoustic jacket-that cannot be represented by a superposition of discrete normal modes. Particular attention is paid to monochromatic point sources of various frequency and depth, and to the surface velocity power that results, both in the discrete f- and p-mode spectrum and in the continuum. It is shown that a major effect of the continuum is to heal the surface wave field produced by compact sources, and therefore to hide them from view. It is found that the continuous spectrum is not a significant contributor to observable inter-ridge seismic power.

  10. A carbon nanotube field emission multipixel x-ray array source for microradiotherapy application

    Science.gov (United States)

    Wang, Sigen; Calderon, Xiomara; Peng, Rui; Schreiber, Eric C.; Zhou, Otto; Chang, Sha

    2011-05-01

    The authors report a carbon nanotube (CNT) field emission multipixel x-ray array source for microradiotherapy for cancer research. The developed multipixel x-ray array source has 50 individually controllable pixels and it has several distinct advantages over other irradiation source including high-temporal resolution (millisecond level), the ability to electronically shape the form, and intensity distribution of the radiation fields. The x-ray array was generated by a CNT cathode array (5×10) chip with electron field emission. A dose rate on the order of >1.2 Gy/min per x-ray pixel beam is achieved at the center of the irradiated volume. The measured dose rate is in good agreement with the Monte Carlo simulation result.

  11. A SMALL UNBALANCED MAGNETRON SPUTTERING SOURCE WITH MULTIPOLE MAGNETIC FIELD ANODE

    Institute of Scientific and Technical Information of China (English)

    郑思孝; 孙官清; 等

    1994-01-01

    A small unbalanced magnetron atom source with multipole cusp magnetic field anode is described.The co-axial magnetron rpinciple is extended to the circular planar magnetron atom source,which raises the efficiency of sputtering target area up to 60%.The multipole magnetic field is put in the anode.which makes the unbalanced magnetron atom source run in a higher discharge current at a lower arc voltage condition.Meanwhile.the sputtering atoms through out the anode can be ionized partially,because the electron reaching the anode have to suffer multiple collisons in order to advance across the multipole magnetic field lines in the anode,which enhances the chemical reactivity of the ejecting atoms in film growth and improve the property of film depositing.

  12. Application of Abaqus to analysis of the temperature field in elements heated by moving heat sources

    Directory of Open Access Journals (Sweden)

    W. Piekarska

    2010-10-01

    Full Text Available Numerical analysis of thermal phenomena occurring during laser beam heating is presented in this paper. Numerical models of surface andvolumetric heat sources were presented and the influence of different laser beam heat source power distribution on temperature field wasanalyzed. Temperature field was obtained by a numerical solution the transient heat transfer equation with activity of inner heat sources using finite element method. Temperature distribution analysis in welded joint was performed in the ABAQUS/Standard solver. The DFLUXsubroutine was used for implementation of the movable welding heat source model. Temperature-depended thermophysical properties for steelwere assumed in computer simulations. Temperature distribution in laser beam surface heated and butt welded plates was numericallyestimated.

  13. The Finite Field Multi-Way Relay Channel with Correlated Sources: The Three-User Case

    CERN Document Server

    Ong, Lawrence; Lechner, Gottfried; Johnson, Sarah J; Kellett, Christopher M

    2011-01-01

    The three-user finite field multi-way relay channel with correlated sources is considered. The three users generate possibly correlated messages, and each user is to transmit its message to the two other users reliably in the Shannon sense. As there is no direct link among the users, communication is carried out via a relay, and the link from the users to the relay and those from the relay to the users are finite field adder channels with additive noise of arbitrary distribution. The problem is to determine the set of all possible achievable rates, defined as channel uses per source symbol for reliable communication. For two classes of source/channel combinations, the solution is obtained using Slepian-Wolf source coding combined with functional-decode-forward channel coding.

  14. Field experiment on coalmine heat disaster governance using cold source from surface water

    Institute of Scientific and Technical Information of China (English)

    Guo Pingye; Zhu Guolong; Liu Yuqing; Duan Mengmeng; Wu Junyin

    2014-01-01

    Regarding the lack of cold source for underground cooling systems from either mine inflow or return air, field experiments were taken in a high temperature deep coal mine with abundant cold source from surface water. Taking Sanhejian coal mine as an example, this paper introduced the technology scheme of heat disaster governance using surface water cold source. The paper presents the basics of this field experiment at the beginning, following by the design and site layout of the cooling system including the analysis and calculation of cold source. Numerical calculation method is also applied based on the operation parameters to simulate the influence to the surface river ecosystem. The results suggest that the temperature of surface water shall be lower than 34 ?C after heat exchange, and when more cooling capacities are needed in the future, increasing the water flow is more favorable than increasing the cooling range of water, which is better for the ecological environment protection.

  15. The Chandra Deep Field-South Survey: 7 Ms Source Catalogs

    CERN Document Server

    Luo, B; Xue, Y Q; Lehmer, B; Alexander, D M; Bauer, F E; Vito, F; Yang, G; Basu-Zych, A R; Comastri, A; Gilli, R; Gu, Q -S; Hornschemeier, A E; Koekemoer, A; Liu, T; Mainieri, V; Paolillo, M; Ranalli, P; Rosati, P; Schneider, D P; Shemmer, O; Smail, I; Sun, M; Tozzi, P; Vignali, C; Wang, J -X

    2016-01-01

    We present X-ray source catalogs for the $\\approx7$ Ms exposure of the Chandra Deep Field-South (CDF-S), which covers a total area of 484.2 arcmin$^2$. Utilizing WAVDETECT for initial source detection and ACIS Extract for photometric extraction and significance assessment, we create a main source catalog containing 1008 sources that are detected in up to three X-ray bands: 0.5-7.0 keV, 0.5-2.0 keV, and 2-7 keV. A supplementary source catalog is also provided including 47 lower-significance sources that have bright ($K_s\\le23$) near-infrared counterparts. We identify multiwavelength counterparts for 992 (98.4%) of the main-catalog sources, and we collect redshifts for 986 of these sources, including 653 spectroscopic redshifts and 333 photometric redshifts. Based on the X-ray and multiwavelength properties, we identify 711 active galactic nuclei (AGNs) from the main-catalog sources. Compared to the previous $\\approx4$ Ms CDF-S catalogs, 291 of the main-catalog sources are new detections. We have achieved unpre...

  16. Investigation of the Parametric Field from a Focusing Source by Using Superposition of Gaussian Beams

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dong; GONG Xiu-Fen; LU Rong-Rong

    2000-01-01

    The superposition method of Gaussian beams is extended to describe the acoustical parametric field from a focusing source. The axial sound pressure of the difference frequency wave 1MHz generated due to the interaction of two primary wave 3.5 and 4.5MHz is theoretically calculated by using 10 items of Gaussian functions. Experimental results coincide well with the calculated results except for the case at the vicinity of the focusing source.

  17. Magnetic Field Disorder and Faraday Effects on the Polarization of Extragalactic Radio Sources

    Science.gov (United States)

    Lamee, Mehdi; Rudnick, Lawrence; Farnes, Jamie S.; Carretti, Ettore; Gaensler, B. M.; Haverkorn, Marijke; Poppi, Sergio

    2016-09-01

    We present a polarization catalog of 533 extragalactic radio sources that have a 2.3 GHz total intensity above 420 mJy from the S-band Polarization All Sky Survey, S-PASS, with corresponding 1.4 GHz polarization information from the NRAO VLA Sky Survey, NVSS. We studied the selection effects and found that fractional polarization, π, of radio objects at both wavelengths depends on the spectral index, the source magnetic field disorder, the source size, and depolarization. The relationship between depolarization, spectrum, and size shows that depolarization occurs primarily in the source vicinity. The median {π }2.3 of resolved objects in NVSS is approximately two times larger than that of unresolved sources. Sources with little depolarization are ∼2 times more polarized than both highly depolarized and re-polarized sources. This indicates that intrinsic magnetic field disorder is the dominant mechanism responsible for the observed low fractional polarization of radio sources at high frequencies. We predict that number counts from polarization surveys will be similar at 1.4 GHz and at 2.3 GHz, for fixed sensitivity, although ∼10% of all sources may currently be missing because of strong depolarization. Objects with {π }1.4≈ {π }2.3≥slant 4 % typically have simple Faraday structures, so they are most useful for background samples. Almost half of flat-spectrum (α ≥slant -0.5) and ∼25% of steep-spectrum objects are re-polarized. Steep-spectrum, depolarized sources show a weak negative correlation of depolarization with redshift in the range 0 < z < 2.3. Previous non-detections of redshift evolution are likely due the inclusion of re-polarized sources as well.

  18. Engineering complex nanolasers: from spaser quantum information sources to near-field anapole lasers

    KAUST Repository

    Gongora, J. S. Totero

    2017-02-16

    In this invited contribution I will review recent results of our research in the field of complex nanolasers. I will begin by discussing recent experimental results from a new type of ultra-dark nanoparticles, which behave as an ideal black-body and spontaneously produce single color pulses thanks to an equivalent Bose-Einstein Condensation of light. I will then discuss new quantum information sources from core-shell spaser nanoparticles. Finally, I will illustrate a new type of laser source that emits only in the near field, discussing applications in integrated optical circuits.

  19. Field structure and electron life times in the MEFISTO electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Bodendorfer, M. [EPFL - Ecole Polytechnique Federale de Lausanne (Switzerland); University of Berne, Institute of Physics, Space Research and Planetary Sciences, Siedlerstrasse 5, 3012 Berne (Switzerland)], E-mail: michael.bodendorfer@space.unibe.ch; Altwegg, K. [University of Berne, Institute of Physics, Space Research and Planetary Sciences, Siedlerstrasse 5, 3012 Berne (Switzerland); Shea, H. [EPFL - Ecole Polytechnique Federale de Lausanne (Switzerland); Wurz, P. [University of Berne, Institute of Physics, Space Research and Planetary Sciences, Siedlerstrasse 5, 3012 Berne (Switzerland)

    2008-03-15

    The complex magnetic field of the permanent magnet electron cyclotron resonance (ECR) ion source MEFISTO located at the University of Berne has been numerically simulated. For the first time the magnetized volume qualified for electron cyclotron resonance at 2.45 GHz and 87.5 mT has been analyzed in highly detailed 3D simulations with unprecedented resolution. New results were obtained from the numerical simulation of 25,211 electron trajectories. The evident characteristic ion sputtering trident of hexapole confined ECR ion sources has been identified with the field and electron trajectory distribution. Furthermore, unexpected long electron trajectory lifetimes were found.

  20. Field structure and electron life times in the MEFISTO electron cyclotron resonance ion source

    Science.gov (United States)

    Bodendorfer, M.; Altwegg, K.; Shea, H.; Wurz, P.

    2008-03-01

    The complex magnetic field of the permanent magnet electron cyclotron resonance (ECR) ion source MEFISTO located at the University of Berne has been numerically simulated. For the first time the magnetized volume qualified for electron cyclotron resonance at 2.45 GHz and 87.5 mT has been analyzed in highly detailed 3D simulations with unprecedented resolution. New results were obtained from the numerical simulation of 25,211 electron trajectories. The evident characteristic ion sputtering trident of hexapole confined ECR ion sources has been identified with the field and electron trajectory distribution. Furthermore, unexpected long electron trajectory lifetimes were found.

  1. Field structure and electron life times in the MEFISTO Electron Cyclotron Resonance Ion Source

    CERN Document Server

    Bodendorfer, Michael; Shea, Herbert; Wurz, Peter

    2008-01-01

    The complex magnetic field of the permanent-magnet electron cyclotron resonance (ECR) ion source MEFISTO located at the University of Bern have been numerically simulated. For the first time the magnetized volume qualified for electron cyclotron resonance at 2.45 GHz and 87.5 mT has been analyzed in highly detailed 3D simulations with unprecedented resolution. New results were obtained from the numerical simulation of 25211 electron trajectories. The evident characteristic ion sputtering trident of hexapole confined ECR sources has been identified with the field and electron trajectory distribution. Furthermore, unexpected long electron trajectory lifetimes were found.

  2. Planar near-field acoustical holography based on equivalent source method and its experimental investigation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yongbin; CHEN Xinzhao; BI Chuanxing; CHEN Jian

    2008-01-01

    The current main approach to reconstruct and predict the acoustic field of a planar source is Near-field Acoustical Holography (NAH) based on FFT. But this method has some disadvantages such as wraparound error and edge Gibbs phenomena which will contaminate the results badly. A planar NAH based on equivalent source approach is developed, which has no wraparound error and edge Gibbs phenomena, and it is beneficial for engineering application.The experimental results of acoustic radiation generated by a point-driven plate with clamped boundaries validate the correctness and availability of the method.

  3. Reconstruction of the sound field above a reflecting plane using the equivalent source method

    Science.gov (United States)

    Bi, Chuan-Xing; Jing, Wen-Qian; Zhang, Yong-Bin; Lin, Wang-Lin

    2017-01-01

    In practical situations, vibrating objects are usually located above a reflecting plane instead of exposing to a free field. The conventional nearfield acoustic holography (NAH) sometimes fails to identify sound sources under such situations. This paper develops two kinds of equivalent source method (ESM)-based half-space NAH to reconstruct the sound field above a reflecting plane. In the first kind of method, the half-space Green's function is introduced into the ESM-based NAH, and the sound field is reconstructed based on the condition that the surface impedance of the reflecting plane is known a prior. The second kind of method regards the reflections as being radiated by equivalent sources placed under the reflecting plane, and the sound field is reconstructed by matching the pressure on the hologram surface with the equivalent sources distributed within the vibrating object and those substituting for reflections. Thus, this kind of method is independent of the surface impedance of the reflecting plane. Numerical simulations and experiments demonstrate the feasibility of these two kinds of methods for reconstructing the sound field above a reflecting plane.

  4. Classical electromagnetic fields from quantum sources in heavy-ion collisions

    Science.gov (United States)

    Holliday, Robert; McCarty, Ryan; Peroutka, Balthazar; Tuchin, Kirill

    2017-01-01

    Electromagnetic fields are generated in high energy nuclear collisions by spectator valence protons. These fields are traditionally computed by integrating the Maxwell equations with point sources. One might expect that such an approach is valid at distances much larger than the proton size and thus such a classical approach should work well for almost the entire interaction region in the case of heavy nuclei. We argue that, in fact, the contrary is true: due to the quantum diffusion of the proton wave function, the classical approximation breaks down at distances of the order of the system size. We compute the electromagnetic field created by a charged particle described initially as a Gaussian wave packet of width 1 fm and evolving in vacuum according to the Klein-Gordon equation. We completely neglect the medium effects. We show that the dynamics, magnitude and even sign of the electromagnetic field created by classical and quantum sources are different.

  5. The Berlin Exoplanet Search Telescope II Catalog of Variable Stars. II. Characterization of the CoRoT SRc02 field

    CERN Document Server

    Klagyivik, P; Pasternacki, T; Cabrera, J; Chini, R; Eigmüller, P; Erikson, A; Fruth, T; Kabath, P; Lemke, R; Murphy, M; Rauer, H; Titz-Weider, R

    2015-01-01

    Time-series photometry of the CoRoT field SRc02 was obtained by the Berlin Exoplanet Search Telescope II (BEST II) in 2009. The main aim was the ground based follow-up of the CoRoT field in order to detect variable stars with better spatial resolution than what can be achieved with the CoRoT space telescope. A total of 1,846 variable stars were detected, of which only 30 have been previously known. For nine eclipsing binaries the stellar parameters were determined by modeling their light curve.

  6. Magnetic fields, stellar feedback, and the geometry of H II Regions

    CERN Document Server

    Ferland, Gary J

    2009-01-01

    Magnetic pressure has long been known to dominate over gas pressure in atomic and molecular regions of the interstellar medium. Here I review several recent observational studies of the relationships between the H^+, H^0 and H_2 regions in M42 (the Orion complex) and M17. A simple picture results. When stars form they push back surrounding material, mainly through the outward momentum of starlight acting on grains, and field lines are dragged with the gas due to flux freezing. The magnetic field is compressed and the magnetic pressure increases until it is able to resist further expansion and the system comes into approximate magnetostatic equilibrium. Magnetic field lines can be preferentially aligned perpendicular to the long axis of quiescent cloud before stars form. After star formation and pushback occurs ionized gas will be constrained to flow along field lines and escape from the system along directions perpendicular to the long axis. The magnetic field may play other roles in the physics of the H II r...

  7. THE NATURAL CONVECTION OF AQUIFERS WITH CONSTANT HEAT SOURCES AND ITS INFLUENCE ON TEMPERATURE FIELDS

    Institute of Scientific and Technical Information of China (English)

    LIU Guo-qing; ZHOU Zhi-fang

    2012-01-01

    By combining sand tank tests with numerical simulations,this paper studies the temperature fields around constant heat sources to reveal the mechanism of the natural convection and its influence on the temperature fields in the process of energy storage.Using the “24-channel temperature auto acquisition system” developed by our research group in the tests,the temperatures are recorded at measuring points within the research area in the tests,the revised Brinkman equation and a transfer-convection balance model are used for solving the aquifer water-thermal coupling problems,and through comparison of the test results with the calculation results,it is discovered that the influence ranges and the variations of the two temperature fields are consistent,which validates the mathematical model.On the basis of this,we also study the influences of the heat source positions and the boundary conditions on the temperature fields,and the results show that,under the natural convection,the heat source positions may influence the distribution of the temperature fields,thus affect the energy storage.For the same energy storage layer,the temperature field for the top energy storage is characterized by a smaller heat influence range and a relatively concentrated temperature distribution.However,when the heat source is at the bottom,the range of a temperature field,and the temperature is relatively dispersed,which is not favorable to heat recycle,with the same heat sourcc position,the boundary conditions determine the size of the critical Rayleigh number,and thus have an influence on the occurrence and the strength of the natural convection,and accordingly,on the temperature fields.

  8. An Algorithm for Joint Estimating Range, DOA and Frequency of Near-Field Sources

    Institute of Scientific and Technical Information of China (English)

    CHENJianfeng; ZHANGXianda; WUYuntao

    2004-01-01

    Most of the existing eigen-decomposition based localization methods make the plane wave assumption in order to estimate the signal parameters of multiple sources. This paper proposes a novel joint algorithm for ranges, DOA's and frequencies of multiple narrow-band sources with the sources in the near field. This algorithm uses the Estimating signal parameters via rotational invariance technique (ESPRIT) based on cumulant-domain signal subspaces. The new algorithm does not require searching spectral peak or pairing among parameters, and has the power to resist an additive Gaussian noise due to use of the fourth-order cumulants. The performance of the new algorithm is confirmed by computer simulations.

  9. Infrared Faint Radio Sources in the Extended Chandra Deep Field South

    Science.gov (United States)

    Huynh, Minh T.

    2009-01-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey (ATLAS) which have no observable counterpart in the Spitzer Wide-area Infrared Extragalactic Survey (SWIRE). The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6 to 70 micron) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the SED of these objects shows that they are consistent with high redshift AGN (z > 2).

  10. Electromagnetic field generated by a modulated moving point source in a planarly layered waveguide

    Science.gov (United States)

    Barrera-Figueroa, V.; Rabinovich, V. S.

    2016-04-01

    In the present work, we consider a modulated point source in an arbitrary motion in an isotropic planarly layered waveguide. The radiation field generated by this source is represented in the form of double oscillatory integrals in terms of the time and the frequency, depending on the large parameter λ. By means of the stationary phase method, we analyze, in the waveguide, the Doppler effect, the retarded time, and the Vavilov-Cherenkov radiation. Numerically, the problem of the moving source is approached by the method of spectral parameter power series.

  11. Horizontal flow fields observed in Hinode G-band images II. Flow fields in the final stages of sunspot decay

    CERN Document Server

    Verma, M; Deng, N; Liu, C; Shimizu, T; Wang, H; Denker, C

    2011-01-01

    We present a subset of multi-wavelengths observations obtained with the Japanese Hinode mission, the Solar Dynamics Observatory (SDO), and the Vacuum Tower Telescope (VTT) at Observatorio del Teide, Tenerife, Spain during the time period from 2010 November 18-23. Horizontal proper motions were derived from G-band and Ca II H images, whereas line-of-sight velocities were extracted from VTT Echelle H-alpha 656.28 nm spectra and Fe I 630.25 nm spectral data of the Hinode/Spectro-Polarimeter, which also provided three-dimensional magnetic field information. The Helioseismic and Magnetic Imager on board SDO provided continuum images and line-of-sight magnetograms as context for the high-resolution observations for the entire disk passage of the active region. We have performed a quantitative study of photospheric and chromospheric flow fields in and around decaying sunspots. In one of the trailing sunspots of active region NOAA 11126, we observed moat flow and moving magnetic features (MMFs), even after its penumb...

  12. EMF Rapid Program Engineering Projects, Project 1, Development of Recommendations for Guidelines for Field Source Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Electric Research and Management, Inc.

    1997-03-11

    The goal of this project is to develop a protocol for measuring the electric and magnetic fields around sources. Data from these measurements may help direct future biological effects research by better defining the complexity of magnetic and electric fields to which humanity is exposed, as well asprovide the basis for rigorous field exposure analysis and risk assessment once the relationship between field exposure and biological response. is better understood. The data base also should have sufficient spatial and temporal characteristics to guide electric and magnetic field management. The goal of Task A is to construct a set of characteristics that would be ideal to have for guiding and interpreting biological studies and for focusing any future effort at field management. This ideal set will then be quantified and reduced according to the availability (or possible development of) instrumentation to measure the desired characteristics. Factors that also will be used to define pragmatic data sets will be the cost of collecting the data, the cost of developing an adequate data base, and the needed precision in measuring specific characteristics. A field, electric or magnetic, will always be ,some function of time and space. The first step in this section of the protocol development will be to determine what span of time and what portion of space are required to quantify the electric and magnetic fields around sources such as appliances and electrical apparatus. Constraints on time will be set by examining measurement limitations and biological data requirements.

  13. D/H isotope ratios of kerogen, bitumen, oil, and water in hydrous pyrolysis of source rocks containing kerogen types-I,-II,IIS, and -III

    Science.gov (United States)

    Schimmelmann, Arndt; Lewan, Michael D.; Wintsch, Robert P.

    1999-11-01

    Immature source rock chips containing different types of kerogen (I, II, IIS, III) were artificially matured in isotopically distinct waters by hydrous pyrolysis and by pyrolysis in supercritical water. Converging isotopic trends of inorganic (water) and organic (kerogen, bitumen, oil) hydrogen with increasing time and temperature document that water-derived hydrogen is added to or exchanged with organic hydrogen, or both, during chemical reactions that take place during thermal maturation. Isotopic mass-balance calculations show that, depending on temperature (310-381°C), time (12-144 h), and source rock type, between ca. 45 and 79% of carbon-bound hydrogen in kerogen is derived from water. Estimates for bitumen and oil range slightly lower, with oil-hydrogen being least affected by water-derived hydrogen. Comparative hydrous pyrolyses of immature source rocks at 330°C for 72 h show that hydrogen in kerogen, bitumen, and expelled oil/wax ranks from most to least isotopically influenced by water-derived hydrogen in the order IIS > II ≈ III > I. Pyrolysis of source rock containing type II kerogen in supercritical water at 381°C for 12 h yields isotopic results that are similar to those from hydrous pyrolysis at 350°C for 72 h, or 330°C for 144 h. Bulk hydrogen in kerogen contains several percent of isotopically labile hydrogen that exchanges fast and reversibly with hydrogen in water vapor at 115°C. The isotopic equilibration of labile hydrogen in kerogen with isotopic standard water vapors significantly reduces the analytical uncertainty of D/H ratios when compared with simple D/H determination of bulk hydrogen in kerogen. If extrapolation of our results from hydrous pyrolysis is permitted to natural thermal maturation at lower temperatures, we suggest that organic D/H ratios of fossil fuels in contact with formation waters are typically altered during chemical reactions, but that D/H ratios of generated hydrocarbons are subsequently little or not affected

  14. D/H isotope ratios of kerogen, bitumen, oil, and water in hydrous pyrolysis of source rocks containing kerogen types I, II, IIS, and III

    Science.gov (United States)

    Schimmelmann, A.; Lewan, M.D.; Wintsch, R.P.

    1999-01-01

    Immature source rock chips containing different types of kerogen (I, II, IIS, III) were artificially matured in isotopically distinct waters by hydrous pyrolysis and by pyrolysis in supercritical water. Converging isotopic trends of inorganic (water) and organic (kerogen, bitumen, oil) hydrogen with increasing time and temperature document that water-derived hydrogen is added to or exchanged with organic hydrogen, or both, during chemical reactions that take place during thermal maturation. Isotopic mass-balance calculations show that, depending on temperature (310-381??C), time (12-144 h), and source rock type, between ca. 45 and 79% of carbon-bound hydrogen in kerogen is derived from water. Estimates for bitumen and oil range slightly lower, with oil-hydrogen being least affected by water-derived hydrogen. Comparative hydrous pyrolyses of immature source rocks at 330??C for 72 h show that hydrogen in kerogen, bitumen, and expelled oil/wax ranks from most to least isotopically influenced by water-derived hydrogen in the order IIS > II ~ III > I. Pyrolysis of source rock containing type II kerogen in supercritical water at 381 ??C for 12 h yields isotopic results that are similar to those from hydrous pyrolysis at 350??C for 72 h, or 330??C for 144 h. Bulk hydrogen in kerogen contains several percent of isotopically labile hydrogen that exchanges fast and reversibly with hydrogen in water vapor at 115??C. The isotopic equilibration of labile hydrogen in kerogen with isotopic standard water vapors significantly reduces the analytical uncertainty of D/H ratios when compared with simple D/H determination of bulk hydrogen in kerogen. If extrapolation of our results from hydrous pyrolysis is permitted to natural thermal maturation at lower temperatures, we suggest that organic D/H ratios of fossil fuels in contact with formation waters are typically altered during chemical reactions, but that D/H ratios of generated hydrocarbons are subsequently little or not affected

  15. Impact of Galactic magnetic field modelling on searches of point sources via UHECR-Neutrino correlations

    CERN Document Server

    Carpio, J A

    2016-01-01

    We use the Jansson-Farrar JF12 magnetic field configuration in the context of point source searches by correlating the Telescope Array ultra-high energy cosmic ray data and the IceCube-40 neutrino candidates. As expected, we have found no correlations, thus, we devote this paper to the study of the effect of different magnetic field hypotheses on the minimum neutrino source flux strength required for a $5\\sigma$ discovery and the derived $90\\%$ CL upper limits. In this study we present a comparison between the JF12 field, that includes a combination of regular and random field components, and the standard turbulent magnetic field used in previous correlation analyses. For a wider perspective, we also incorporate in our comparison the cases of no magnetic field and the JF12 regular component alone and consider different power law indices $\\alpha=2,\\alpha=2.3$ for the neutrino point source flux. Collaterally, a novel parameterisation of the JF12 random component is introduced. We have observed that the discover...

  16. Two field trials for deblending of simultaneous source surveys: Why we failed and why we succeeded?

    Science.gov (United States)

    Zu, Shaohuan; Zhou, Hui; Chen, Haolin; Zheng, Hao; Chen, Yangkang

    2017-08-01

    Currently, deblending is the main strategy for dealing with the intense interference problem of simultaneous source data. Most deblending methods are based on the property that useful signal is coherent while the interference is incoherent in some domains other than common shot domain. In this paper, two simultaneous source field trials were studied in detail. In the first trial, the simultaneous source survey was not optimal, as the dithering code had strong coherency and the minimum distance between the two vessels was also small. The chosen marine shot scheduling and vessel deployment made it difficult to deblend the simultaneous source data, and result was an unexpected failure. Next, we tested different parameters (the dithering code and the minimum distance between vessels) of the simultaneous source survey using the simulated blended data and got some useful insights. Then, we carried out the second field trial with a carefully designed survey that was much different from the first trial. The deblended results in common receiver gather, common shot gather or the final stacked profile were encouraging. We obtained a complete success in the second field trial, which gave us confidence in the further test (such as a full three dimensional acquisition test or a high-resolution acquisition test with denser spatial sampling). Remembering that failures with simultaneous sourcing seldom reported, in this paper, our contribution is the discussion in detail about both our failed and successful field experiments and the lessons we have learned from them with the hope that the experience gained from this study can be very useful to other researchers in the same field.

  17. Electron optics simulation for designing carbon nanotube based field emission x-ray source

    Science.gov (United States)

    Sultana, Shabana

    In this dissertation, electron optics simulation for designing carbon nanotube (CNT) based field emission x-ray source for medical imaging applications will be presented. However, for design optimization of x-ray tubes accurate electron beam optics simulation is essential. To facilitate design of CNT x-ray sources a commercial 3D finite element software has been chosen for extensive simulation. The results show that a simplified model of uniform electron field emission from the cathode surface is not sufficient when compared to experimental measurements. This necessitated the development of a refined model to describe a macroscopic field emission CNT cathode for electron beam optics simulations. The model emulates the random distribution of CNTs and the associated variation of local field enhancement factor. The main parameter of the model has been derived empirically from the experimentally measured I-V characteristics of the CNT cathode. Simulation results based on this model agree well with experiments which include measurements of the transmission rate and focus spot size. The model provides a consistent simulation platform for optimization of electron beam optics in CNT x-ray source design. A systematic study of electron beam optics in CNT x-ray tubes led to the development of a new generation of compact x-ray source with multiple pixels. A micro focus field emission x-ray source with a variable focal spot size has been fully characterized and evaluated. It has been built and successfully integrated into micro-CT scanners which are capable of dynamic cardiac imaging of free-breathing small animals with high spatial and temporal resolutions. In addition a spatially distributed high power multi-beam x-ray source has also been designed and integrated into a stationary digital breast tomosynthesis (s-DBT) configuration. This system has the potential to reduce the total scan time to 4 seconds and yield superior image quality in breast imaging.

  18. Source and path effects in the wave fields of tremor and explosions at Stromboli Volcano, Italy

    Science.gov (United States)

    Chouet, B.; Saccorotti, G.; Martini, M.; Dawson, P.; De Luca, G.; Milana, G.; Scarpa, R.

    1997-01-01

    The wave fields generated by Strombolian activity are investigated using data from small-aperture seismic arrays deployed on the north flank of Stromboli and data from seismic and pressure transducers set up near the summit crater. Measurements of slowness and azimuth as a function of time clearly indicate that the sources of tremor and explosions are located beneath the summit crater at depths shallower than 200 m with occasional bursts of energy originating from sources extending to a depth of 3 km. Slowness, azimuth, and particle motion measurements reveal a complex composition of body and surface waves associated with topography, structure, and source properties. Body waves originating at depths shallower than 200 m dominate the wave field at frequencies of 0.5-2.5 Hz, and surface waves generated by the surficial part of the source and by scattering sources distributed around the island dominate at frequencies above 2.5 Hz. The records of tremor and explosions are both dominated by SH motion. Far-field records from explosions start with radial motion, and near-field records from those events show dominantly horizontal motion and often start with a low-frequency (1-2 Hz) precursor characterized by elliptical particle motion, followed within a few seconds by a high-frequency radial phase (1-10 Hz) accompanying the eruption of pyroclastics. The dominant component of the near- and far-field particle motions from explosions, and the timing of air and body wave phases observed in the near field, are consistent with a gaspiston mechanism operating on a shallow (<200 m deep), vertical crack-like conduit. Models of a degassing fluid column suggest that noise emissions originating in the collective oscillations of bubbles ascending in the magma conduit may provide an adequate self-excitation mechanism for sustained tremor generation at Stromboli. Copyright 1997 by the American Geophysical Union.

  19. Molecular Mechanics (MM) Force Fields for Modelling of Copper(II) Amino Acid Complexes in Different Environments

    Science.gov (United States)

    Sabolović, Jasmina

    2009-03-01

    New MM force field developed for modelling the properties of copper(II) complexes with aliphatic amino acid in vacuo, in crystal, and in aqueous solution was applied to study conformational properties of bis(N,N-diethylglycinato)copper(II). Two hypotheses are examined and confirmed as true: (i) the conformations which do not allow apical coordination to the copper(II) are the most stable in vacuo and in aqueous solution; (ii) MM calculations quantitatively support the supposition that the experimentally observed conformer is better suited for crystal packing than the in vacuo and in solution most stable conformers.

  20. New 20-CM Radio-Continuum Study of The Small Magellanic Cloud: Part II - Point Sources Catalogue

    CERN Document Server

    Wong, G F; Crawford, E J; Tothill, N F H; Drasković, A Y De Horta D; Galvin, T J; Collier, J D; Payne, J L

    2011-01-01

    We present a new catalogue of point radio-continuum sources in the field of the Small Magellanic Cloud (SMC). This catalogue also contains point sources previously not found in 2300 MHz (\\lambda=13 cm) with sources found at 1400 MHz (\\lambda=20 cm) and 843 MHz (\\lambda=36 cm). We found 1576 point sources at 20 cm image that is created from new high sensitivity and resolution radio-continuum images of the SMC from Paper I. Some 46 new point sources have been detected at 13 cm as an addition the Filipovi\\'c et al. (2002) catalogue. We also created a 36 cm catalogue to which we listed 1692 point radio-continuum sources. Follow up studies on these sources nature will be presented in Paper III of this series.

  1. The fluctuation Hall conductivity and the Hall angle in type-II superconductor under magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Tinh, Bui Duc, E-mail: tinhbd@hnue.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam); Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam); Hoc, Nguyen Quang; Thu, Le Minh [Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam)

    2016-02-15

    Highlights: • The time-dependent Ginzburg–Landau was used to calculate fluctuation Hall conductivity and Hall angle in type-II superconductor in 2D and 3D. • We obtain analytical expressions for the fluctuation Hall conductivity and the Hall angle summing all Landau levels without need to cutoff higher Landau levels to treat arbitrary magnetic field. • The results were compared to the experimental data on YBCO. - Abstract: The fluctuation Hall conductivity and the Hall angle, describing the Hall effect, are calculated for arbitrary value of the imaginary part of the relaxation time in the frame of the time-dependent Ginzburg–Landau theory in type II-superconductor with thermal noise describing strong thermal fluctuations. The self-consistent Gaussian approximation is used to treat the nonlinear interaction term in dynamics. We obtain analytical expressions for the fluctuation Hall conductivity and the Hall angle summing all Landau levels without need to cutoff higher Landau levels to treat arbitrary magnetic field. The results are compared with experimental data on high-T{sub c} superconductor.

  2. Stage II Chronic Maxillary Atelectasis Associated with Subclinical Visual Field Defect

    Directory of Open Access Journals (Sweden)

    Mangussi-Gomes, João

    2013-09-01

    Full Text Available Introduction: Chronic maxillary atelectasis (CMA is characterized by a persistent decrease in the maxillary sinus volume due to inward bowing of its walls. According to its severity, it may be classified into three clinical-radiological stages. Objective: To report a case of stage II CMA associated with subclinical visual field defect. Case Report: A 34-year-old woman presented with a 15-year history of recurrent episodes of sinusitis and intermittent right facial discomfort for the past 5 years. She denied visual complaints, and no facial deformities were observed on physical examination. Paranasal sinus computed tomography (CT demonstrated a completely opacified right maxillary sinus with inward bowing of its walls, suggesting the diagnosis of stage II CMA. A computerized campimetry (CC disclosed a scotoma adjacent to the blind spot of the right eye, indicating a possible damage to the optic nerve. The patient was submitted to functional endoscopic sinus surgery, with drainage of a thick mucous fluid from the sinus. She did well after surgery and has been asymptomatic since then. Postoperative CT was satisfactory and CC was normal. Discussion: CMA occurs because of a persistent ostiomeatal obstruction, which creates negative pressure inside the sinus. It is associated with nasosinusal symptoms but had never been described in association with any visual field defect. It can be divided into stage I (membranous deformity, stage II (bony deformity, and stage III (clinical deformity. The silent sinus syndrome is a special form of CMA. This term should only be used to describe those cases with spontaneous enophthalmos, hypoglobus, and/or midfacial deformity in the absence of nasosinusal symptoms.

  3. Expansion design for a radioactive sources handling laboratory type II class B; Diseno de ampliacion para un laboratorio de manejo de fuentes radiactivas tipo II clase B

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez S, P. S. [Universidad Mexiquense del Bicentenario, Av. Industria Poniente s/n, Parque Industrial Dona Rosa, 52000 Lerma, Estado de Mexico (Mexico); Monroy G, F.; Alanis, J., E-mail: salvador-21@live.com.mx [ININ, Carretera Mexico-Touca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2013-10-15

    The Radioactive Wastes Research Laboratory (RWRL) of the Instituto Nacional de Investigaciones Nucleares (Mexico), at the moment has three sections: instrumental analysis, radioactive material processes, counting and a license type II class C, to manipulate radioactive material. This license limits the open sources handling to 300 kBq for radionuclides of very high radio-toxicity as the Ra-226, for what is being projected the license extension to type II class B, to be able to manage until 370 MBq of this radionuclides type, and the Laboratory, since the location where is the RWRL have unused area. This work presents a proposal of the RWRL expansion, taking into account the current laboratory sections, as well as the established specifications by the Comision Nacional de Seguridad Nuclear y Salvaguardias (CNSNS). The current planes of the RWRL and the expansion proposal of the laboratory are presented. (Author)

  4. Modeling and analysis of secondary sources coupling for active sound field reduction in confined spaces

    Science.gov (United States)

    Montazeri, Allahyar; Taylor, C. James

    2017-10-01

    This article addresses the coupling of acoustic secondary sources in a confined space in a sound field reduction framework. By considering the coupling of sources in a rectangular enclosure, the set of coupled equations governing its acoustical behavior are solved. The model obtained in this way is used to analyze the behavior of multi-input multi-output (MIMO) active sound field control (ASC) systems, where the coupling of sources cannot be neglected. In particular, the article develops the analytical results to analyze the effect of coupling of an array of secondary sources on the sound pressure levels inside an enclosure, when an array of microphones is used to capture the acoustic characteristics of the enclosure. The results are supported by extensive numerical simulations showing how coupling of loudspeakers through acoustic modes of the enclosure will change the strength and hence the driving voltage signal applied to the secondary loudspeakers. The practical significance of this model is to provide a better insight on the performance of the sound reproduction/reduction systems in confined spaces when an array of loudspeakers and microphones are placed in a fraction of wavelength of the excitation signal to reduce/reproduce the sound field. This is of particular importance because the interaction of different sources affects their radiation impedance depending on the electromechanical properties of the loudspeakers.

  5. The source of the intermediate wavelength component of the Earth's magnetic field

    Science.gov (United States)

    Harrison, C. G. A.

    1985-01-01

    The intermediate wavelength component of the Earth's magnetic field has been well documented by observations made by MAGSAT. It has been shown that some significant fraction of this component is likely to be caused within the core of the Earth. Evidence for this comes from analysis of the intermediate wavelength component revealed by spherical harmonics between degrees 14 and 23, in which it is shown that it is unlikely that all of this signal is crustal. Firstly, there is no difference between average continental source strength and average oceanic source strength, which is unlikely to be the case if the anomalies reside within the crust, taking into account the very different nature and thickness of continental and oceanic crust. Secondly, there is almost no latitudinal variation in the source strength, which is puzzling if the sources are within the crust and have been formed by present or past magnetic fields with a factor of two difference in intensity between the equator and the poles. If however most of the sources for this field reside within the core, then these observations are not very surprising.

  6. General relativistic radiation hydrodynamics of accretion flows - II. Treating stiff source terms and exploring physical limitations

    Science.gov (United States)

    Roedig, C.; Zanotti, O.; Alic, D.

    2012-10-01

    We present the implementation of an implicit-explicit (IMEX) Runge-Kutta numerical scheme for general relativistic (GR) hydrodynamics coupled to an optically thick radiation field in two existing GR-(magneto)hydrodynamics codes. We argue that the necessity of such an improvement arises naturally in most astrophysically relevant regimes where the optical thickness is high as the equations become stiff. By performing several simple 1D tests, we verify the codes' new ability to deal with this stiffness and show consistency. Then, still in one spatial dimension, we compute a luminosity versus accretion rate diagram for the set-up of spherical accretion on to a Schwarzschild black hole and find good agreement with previous work which included more radiation processes than we currently have available. Lastly, we revisit the supersonic Bondi-Hoyle-Lyttleton (BHL) accretion in two dimensions where we can now present simulations of realistic temperatures, down to T ˜ 106 K or less. Here we find that radiation pressure plays an important role, but also that these highly dynamical set-ups push our approximate treatment towards the limit of physical applicability. The main features of radiation hydrodynamics BHL flows manifest as (i) an effective adiabatic index approaching γeff ˜ 4/3; (ii) accretion rates two orders of magnitude lower than without radiation pressure, but still super-Eddington; (iii) luminosity estimates around the Eddington limit, hence with an overall radiative efficiency as small as ηBHL˜10-2; (iv) strong departures from thermal equilibrium in shocked regions; (v) no appearance of the flip-flop instability. We conclude that the current optically thick approximation to the radiation transfer does give physically substantial improvements over the pure hydro also in set-ups departing from equilibrium, and, once accompanied by an optically thin treatment, is likely to provide a fundamental tool for investigating accretion flows in a large variety of

  7. Second-order spatial correlation in the far-field: Comparing entangled and classical light sources

    Science.gov (United States)

    Zhang, Erfeng; Liu, Weitao; Lin, Huizu; Chen, Pingxing

    2016-02-01

    We consider second-order spatial correlation with entangled and classical light in the far-field. The quantum theory of second-order spatial correlation is analyzed, and the role of photon statistics and detection mode in the second-order spatial correlation are discussed. Meanwhile, the difference of second-order spatial correlation with entangled and classical light sources is deduced.

  8. Field sources in a Lorentz-symmetry breaking scenario with a single background vector

    Energy Technology Data Exchange (ETDEWEB)

    Borges, L.H.C. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [IFQ, Universidade Federal de Itajuba, Av. BPS 1303, Pinheirinho, Caixa Postal 50, Itajuba, MG (Brazil); Helayel-Neto, J.A. [Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, RJ (Brazil)

    2014-06-15

    This paper is devoted to an investigation of the interactions between stationary sources of the electromagnetic field, in a model which exhibits explicit Lorentz-symmetry breaking due to the presence of a single background vector. We focus on physical phenomena that emerge from this kind of breaking and which have no counterpart in Maxwell electrodynamics. (orig.)

  9. FieldTrip: Open source software for advanced analysis of MEG, EEG, and invasive electrophysiological data

    NARCIS (Netherlands)

    Oostenveld, R.; Fries, P.; Maris, E.; Schoffelen, J.M.

    2011-01-01

    This paper describes FieldTrip, an open source software package that we developed for the analysis of MEG, EEG, and other electrophysiological data. The software is implemented as a MATLAB toolbox and includes a complete set of consistent and user-friendly high-level functions that allow experimenta

  10. Field Plate Optimization in Low-Power High-Gain Source-Gated Transistors

    NARCIS (Netherlands)

    Sporea,R.A.; Trainor, M.J.; Young, N.D.; Shannon, J.M.; Silva, S.R.P.

    2012-01-01

    Source-gated transistors (SGTs) have potentially very high output impedance and low saturation voltages, which make them ideal as building blocks for high performance analog circuits fabricated in thin-film technologies. The quality of the saturation is greatly influenced by the design of the field-

  11. MOBILE PHONE AS A SOURCE OF ARTIFICIAL EXPOSURE OF ELECTROMAGNETIC FIELDS ON THE POPULATION

    Directory of Open Access Journals (Sweden)

    A. N. Liberman

    2011-01-01

    Full Text Available The paper presents characteristics  of the main sources of artificial exposure of electromagnetic fields on the population. Particular attention is drawn to the means of mobile telecommunication that became commonplace in the world, mobile and cordless (home phones.

  12. Environmental monitoring survey of oil and gas fields in Region II in 2009. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    2010-03-15

    The oil companies Statoil ASA, ExxonMobil Exploration and Production Norway AS, Total E&P Norge AS, Talisman Energy Norge AS and Marathon Petroleum Norge AS commissioned Section of Applied Environmental Research at UNI RESEARCH AS to undertake the monitoring survey of Region II in 2009. Similar monitoring surveys in Region II have been carried out in 1996, 2000, 2003 and 2006. The survey in 2009 included in total 18 fields: Rev, Varg, Sigyn, Sleipner Vest, Sleipner OEst, Sleipner Alfa Nord, Glitne, Grane, Balder, Ringhorne, Jotun, Vale, Skirne, Byggve, Heimdal, Volve, Vilje og Alvheim. Sampling was conducted from the vessel MV Libas between May 18 and May 27. Samples were collected from in totally 137 sampling sites, of which 15 were regional sampling sites. Samples for chemical analysis were collected at all sites, whereas samples for benthos analysis were collected at 12 fields. As in previous surveys, Region II is divided into natural sub-regions. One sub-region is shallow (77-96 m) sub-region, a central sub-region (107-130 m) and a northern subregion (115-119 m). The sediments of the shallow sub-region had relatively lower content of TOM and pelite and higher content of fine sand than the central and northern sub-regions. Calculated areas of contamination are shown for the sub-regions in Table 1.1. The fields Sigyn, Sleipner Alfa Nord, Glitne, Grane, Balder, Ringhorne, Jotun, Skirne, Byggve, Vilje og Alvheim showed no contamination of THC. At the other fields there were minor changes from 2006. The concentrations of barium increased in the central sub-region from 2006 to 2009, also at fields where no drilling had been undertaken during the last years. The same laboratory and methods are used during the three last regional investigations. The changes in barium concentrations may be due to high variability of barium concentrations in the sediments. This is supported by relatively large variations in average barium concentrations at the regional sampling sites in

  13. Phase II: Field Detector Development For Undeclared/Declared Nuclear Testing For Treaty Verfiation Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kriz, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hunter, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Riley, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-02

    Radioactive xenon isotopes are a critical part of the Comprehensive Nuclear Test Ban Treaty (CTBT) for the detection or confirmation of nuclear weapons tests as well as on-site treaty verification monitoring. On-site monitoring is not currently conducted because there are no commercially available small/robust field detector devices to measure the radioactive xenon isotopes. Xenon is an ideal signature to detect clandestine nuclear events since they are difficult to contain and can diffuse and migrate through soils due to their inert nature. There are four key radioxenon isotopes used in monitoring: 135Xe (9 hour half-life), 133mXe (2 day half-life), 133Xe (5 day half-life) and 131mXe (12 day half-life) that decay through beta emission and gamma emission. Savannah River National Laboratory (SRNL) is a leader in the field of gas collections and has developed highly selective molecular sieves that allow for the collection of xenon gas directly from air. Phase I assessed the development of a small, robust beta-gamma coincidence counting system, that combines collection and in situ detection methodologies. Phase II of the project began development of the custom electronics enabling 2D beta-gamma coincidence analysis in a field portable system. This will be a significant advancement for field detection/quantification of short-lived xenon isotopes that would not survive transport time for laboratory analysis.

  14. Study of Near-Field Vibration Sources for the NLC Linac Components

    CERN Document Server

    Le Pimpec, F

    2003-01-01

    The vibration stability requirements for the Next Linear Collider (NLC) are far more stringent than for the previous generation of Colliders. To meet these goals, it is imperative that the effects of vibration on NLC Linac components from near-field sources (e.g. compressors, high vacuum equipment, klystrons, modulators, pumps, fans, etc) be well understood. The civil construction method, whether cut-and-cover or parallel bored tunnels, can determine the proximity and possible isolation of noise sources. This paper presents a brief summary and analysis of recently completed and planned studies for characterization of near-field vibration sources under either construction method. The results of in-situ vibration measurements will also be included.

  15. Effects of Electromagnetic Field on The Collapse and Expansion of Anisotropic Gravitating Source

    CERN Document Server

    Abbas, G

    2013-01-01

    This paper is devoted to study the effects of electromagnetic on the collapse and expansion of anisotropic gravitating source. For this purpose, we have evaluated the generating solutions of Einstein-Maxwell field equations with spherically symmetric anisotropic gravitating source. Such solutions exit only due to the absence of heat flux in the source. We found that a single function generates the various anisotropic solutions. In this case every generating function involves an arbitrary function of time which can be chosen to fit several astrophysical time profiles. Two physical phenomenon occur, one is gravitational collapse and other is the cosmological expanding solution. In both cases electromagnetic field effects the anisotropy of the model. For collapse the anisotropy is increased while for expansion it deceases from maximum value to finite positive value. In case of collaps there exits two horizons like in case of Reissner-Nordstr$\\ddot{o}$m metric.

  16. The VLA Survey of the Chandra Deep Field South. IV. Source Population

    CERN Document Server

    Padovani, P; Tozzi, P; Kellermann, K I; Fomalont, E B; Miller, N; Rosati, P; Shaver, P

    2008-01-01

    We present a detailed analysis of 256 radio sources from our deep (flux density limit of 42 microJy at the field centre at 1.4 GHz) Chandra Deep Field South 1.4 and 5 GHz VLA survey. The radio population is studied by using a wealth of multi-wavelength information in the radio, optical, and X-ray bands. The availability of redshifts for ~ 80% of the sources in our complete sample allows us to derive reliable luminosity estimates for the majority of the objects. X-ray data, including upper limits, for all our sources turn out to be a key factor in establishing the nature of faint radio sources. Due to the faint optical levels probed by this study, we have uncovered a population of distant Active Galactic Nuclei (AGN) systematically missing from many previous studies of sub-millijansky radio source identifications. We find that, while the well-known flattening of the radio number counts below 1 mJy is mostly due to star forming galaxies, these sources and AGN make up an approximately equal fraction of the sub-m...

  17. Segmenting Multi-Source images using hidden Markov fields with copula-based multivariate statistical distributions.

    Science.gov (United States)

    Lapuyade-Lahorgue, Jerome; Xue, Jing-Hao; Ruan, Su

    2017-03-21

    Nowadays, multi-source image acquisition attracts an increasing interest in many fields such as multi-modal medical image segmentation. Such acquisition aims at considering complementary information to perform image segmentation since the same scene has been observed by various types of images. However, strong dependency often exists between multi-source images. This dependency should be taken into account when we try to extract joint information for precisely making a decision. In order to statistically model this dependency between multiple sources, we propose a novel multi-source fusion method based on the Gaussian copula. The proposed fusion model is integrated in a statistical framework with the hidden Markov field inference in order to delineate a target volume from multi-source images. Estimation of parameters of the models and segmentation of the images are jointly performed by an iterative algorithm based on Gibbs sampling. Experiments are performed on multi-sequence MRI to segment tumors. The results show that the proposed method based on the Gaussian copula is effective to accomplish multi-source image segmentation.

  18. The Three-User Finite Field Multi-Way Relay Channel with Correlated Sources

    CERN Document Server

    Ong, Lawrence; Lechner, Gottfried; Johnson, Sarah J; Kellett, Christopher M

    2012-01-01

    This paper studies the three-user finite field multi-way relay channel with correlated sources, where three users exchange possibly correlated messages via a relay. Full data exchange is considered where each user is to decode the messages from the other two users. There is no direct link among the users; the uplink from the users to the relay and the downlinks from the relay to the users are finite field adder channels with independent additive noise of arbitrary distributions. The problem is to determine the set of all achievable rates, defined as channel uses per source symbol for reliable communication. Using the Slepian-Wolf source coding and a functional-decode-forward channel coding scheme, the solution is obtained for two classes of source and channel combinations. Furthermore, for correlated sources with common cores, two new functional-decode-forward coding schemes are constructed and are shown to obtain the set of all achievable rates for any source and channel combination.

  19. Geochemistry of Eagle Ford group source rocks and oils from the first shot field area, Texas

    Science.gov (United States)

    Edman, Janell D.; Pitman, Janet K.; Hammes, Ursula

    2010-01-01

    Total organic carbon, Rock-Eval pyrolysis, and vitrinite reflectance analyses performed on Eagle Ford Group core and cuttings samples from the First Shot field area, Texas demonstrate these samples have sufficient quantity, quality, and maturity of organic matter to have generated oil. Furthermore, gas chromatography and biomarker analyses performed on Eagle Ford Group oils and source rock extracts as well as weight percent sulfur analyses on the oils indicate the source rock facies for most of the oils are fairly similar. Specifically, these source rock facies vary in lithology from shales to marls, contain elevated levels of sulfur, and were deposited in a marine environment under anoxic conditions. It is these First Shot Eagle Ford source facies that have generated the oils in the First Shot Field. However, in contrast to the generally similar source rock facies and organic matter, maturity varies from early oil window to late oil window in the study area, and these maturity variations have a pronounced effect on both the source rock and oil characteristics. Finally, most of the oils appear to have been generated locally and have not experienced long distance migration. 

  20. Residential magnetic field: Accounting for external sources and residential grounding circuits

    Energy Technology Data Exchange (ETDEWEB)

    Barrow, D.A.

    1989-06-14

    A project to characterize the sources of magnetic fields in residential locations was established as part of Ontario Hydro's program to assess the risks, if any, posed by fields due to the electric power system. In this report, a simple model for the strength of the magnetic field at 60 Hz found inside houses is developed to account for the house wiring, and for sources external to the house. In the model the house wiring is reduced to a single circuit carrying the net current on the service drop to the house and the service grounding current. All sources external to the house are combined and represented as a single ambient field assumed to be spatially uniform throughout the volume of the house. This model and a measurmement procedure were tested on 5 houses in locations inside the houses remote from appliances, which were not included in the model. In the main, good agreement was found between actual measured field strengths and those predicted by the model. 4 refs., 10 figs., 6 tabs.

  1. Influence of head models on neuromagnetic fields and inverse source localizations

    Directory of Open Access Journals (Sweden)

    Schimpf Paul H

    2006-10-01

    Full Text Available Abstract Background The magnetoencephalograms (MEGs are mainly due to the source currents. However, there is a significant contribution to MEGs from the volume currents. The structure of the anatomical surfaces, e.g., gray and white matter, could severely influence the flow of volume currents in a head model. This, in turn, will also influence the MEGs and the inverse source localizations. This was examined in detail with three different human head models. Methods Three finite element head models constructed from segmented MR images of an adult male subject were used for this study. These models were: (1 Model 1: full model with eleven tissues that included detailed structure of the scalp, hard and soft skull bone, CSF, gray and white matter and other prominent tissues, (2 the Model 2 was derived from the Model 1 in which the conductivity of gray matter was set equal to the white matter, i.e., a ten tissuetype model, (3 the Model 3 consisted of scalp, hard skull bone, CSF, gray and white matter, i.e., a five tissue-type model. The lead fields and MEGs due to dipolar sources in the motor cortex were computed for all three models. The dipolar sources were oriented normal to the cortical surface and had a dipole moment of 100 μA meter. The inverse source localizations were performed with an exhaustive search pattern in the motor cortex area. A set of 100 trial inverse runs was made covering the 3 cm cube motor cortex area in a random fashion. The Model 1 was used as a reference model. Results The reference model (Model 1, as expected, performed best in localizing the sources in the motor cortex area. The Model 3 performed the worst. The mean source localization errors (MLEs of the Model 3 were larger than the Model 1 or 2. The contour plots of the magnetic fields on top of the head were also different for all three models. The magnetic fields due to source currents were larger in magnitude as compared to the magnetic fields of volume currents

  2. Chandra view of the dynamically young cluster of galaxies A1367 II. point sources

    CERN Document Server

    Sun, M

    2002-01-01

    A 40 ks \\emph{Chandra} ACIS-S observation of the dynamically young cluster A1367 yields new insights on X-ray emission from cluster member galaxies. We detect 59 point-like sources in the ACIS field, of which 8 are identified with known cluster member galaxies. Thus in total 10 member galaxies are detected in X-rays when three galaxies discussed in paper I (Sun & Murray 2002; NGC 3860 is discussed in both papers) are included. The superior spatial resolution and good spectroscopy capability of \\chandra allow us to constrain the emission nature of these galaxies. Central nuclei, thermal halos and stellar components are revealed in their spectra. Four new low luminosity nuclei (LLAGN) are found, including an absorbed one (NGC 3861). This discovery makes the LLAGN/AGN content in this part of A1367 very high ($\\sim$ 20%). Thermal halos with temperatures around 0.5 - 0.8 keV are revealed in the spectra of two elliptical galaxies NGC 3842 and NGC 3837, which suggests that galactic coronae can survive in cluster...

  3. Five years of searches for point sources of astrophysical neutrinos with the AMANDA-II neutrino telescope

    CERN Document Server

    Achterberg, A; Adams, J; Ahrens, J; Andeen, K; Atlee, D W; Bahcall, J N; Bai, X; Baret, B; Barwick, S W; Bay, R; Beattie, K; Becka, T; Becker, J K; Becker, K H; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Blaufuss, E; Boersma, D J; Bohm, C; Bolmont, J; Boser, S; Botner, O; Bouchta, A; Braun, J; Burgess, C; Burgess, T; Castermans, T; Chirkin, D; Christy, B; Clem, J; Cowen, D F; D'Agostino, M V; Davour, A; Day, C T; De Clercq, C; Demirors, L; Descamps, F; Desiati, P; De Young, T; Díaz-Veléz, J C; Dreyer, J; Dumm, J P; Duvoort, M R; Edwards, W R; Ehrlich, R; Eisch, J; Ellsworth, R W; Evenson, P A; Fadiran, O; Fazely, A R; Feser, T; Filimonov, K; Fox, B D; Gaisser, T K; Gallagher, J; Ganugapati, R; Geenen, H; Gerhardt, L; Goldschmidt, A; Goodman, J A; Gozzini, R; Grullon, S; Gross, A; Gunasingha, R M; Gurtner, M; Hallgren, A; Halzen, F; Han, K; Hanson, K; Hardtke, D; Hardtke, R; Harenberg, T; Hart, J E; Hauschildt, T; Hays, D; Heise, J; Helbing, K; Hellwig, M; Herquet, P; Hill, G C; Hodges, J; Hoffman, K D; Hommez, B; Hoshina, K; Hubert, D; Hughey, B; Hulth, P O; Hultqvist, K; Hundertmark, S; Hulss, J P; Ishihara, A; Jacobsen, J; Japaridze, G S; Johansson, H; Jones, A; Joseph, J M; Kampert, K H; Karle, A; Kawai, H; Kelley, J L; Kestel, M; Kitamura, N; Klein, S R; Klepser, S; Kohnen, G; Kolanoski, H; Kowalski, M; Köpke, L; Krasberg, M; Kühn, K; Landsman, H; Leich, H; Leier, D; Leuthold, M; Liubarsky, I; Lundberg, J; Lunemann, J; Madsen, J; Mase, K; Matis, H S; McCauley, T; McParland, C P; Meli, A; Messarius, T; Mészáros, P; Miyamoto, H; Mokhtarani, A; Montaruli, T; Morey, A; Morse, R; Movit, S M; Munich, K; Nahnhauer, R; Nam, J W; Niessen, P; Nygren, D R; Ogelman, H; Olivas, A; Patton, S; Peña-Garay, C; Pérez de los Heros, C; Piegsa, A; Pieloth, D; Pohl, A C; Porrata, R; Pretz, J; Price, P B; Przybylski, G T; Rawlins, K; Razzaque, S; Resconi, E; Rhode, W; Ribordy, M; Rizzo, A; Robbins, S; Roth, P; Rott, C; Rutledge, D; Ryckbosch, D; Sander, H G; Sarkar, S; Schlenstedt, S; Schmidt, T; Schneider, D; Seckel, D; Seo, S H; Seunarine, S; Silvestri, A; Smith, A J; Solarz, M; Song, C; Sopher, J E; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Steffen, P; Stezelberger, T; Stokstad, R G; Stoufer, M C; Stoyanov, S; Strahler, E A; Straszheim, T; Sulanke, K H; Sullivan, G W; Sumner, T J; Taboada, I; Tarasova, O; Tepe, A; Thollander, L; Tilav, S; Tluczykont, M; Toale, P A; Turcan, D; van Eijndhoven, N; Vandenbroucke, J; Van Overloop, A; Voigt, B; Wagner, W; Walck, C; Waldmann, H; Walter, M; Wang, Y R; Wendt, C; Wiebusch, C; Wikström, G; Williams, D R; Wischnewski, R; Wissing, H; Woschnagg, K; Xu, X W; Yodh, G; Yoshida, S; De Dios-Zornoza-Gomez, Juan

    2006-01-01

    We report the results of a five-year survey of the northern sky to search for point sources of high energy neutrinos. The search was performed on the data collected with the AMANDA-II neutrino telescope in the years 2000 to 2004, with a live-time of 1001 days. The sample of selected events consists of 4282 upward going muon tracks with high reconstruction quality and an energy larger than about 100 GeV. We found no indication of point sources of neutrinos and set 90% confidence level flux upper limits for an all-sky search and also for a catalog of 32 selected sources. For the all-sky search, our average (over declination and right ascension) experimentally observed upper limit \\Phi^{0}=(E/TeV)^\\gamma d\\Phi/dE to a point source flux of muon and tau neutrino (detected as muons arising from taus) is \\Phi_{\

  4. Search for extraterrestrial point sources of high energy neutrinos with AMANDA-II using data collected in 2000-2002

    CERN Document Server

    Ackermann, M; Bai, X; Bay, R; Bartelt, M; Barwick, S W; Becka, T; Becker, K H; Becker, J K; Bernardini, E; Bertrand, D; Boersma, D J; Boser, S; Botner, O; Bouchta, A; Bouhali, O; Braun, J; Burgess, C; Burgess, T; Castermans, T; Chirkin, D; Collin, B; Conrad, J; Cooley, J; Cowen, D F; Davour, A; De Clercq, C; De Young, T R; Desiati, P; Ekstrom, P; Feser, T; Gaisser, T K; Ganugapati, R; Geenen, H; Gerhardt, L; Goldschmidt, A; Gross, A; Hallgren, A; Halzen, F; Hanson, K; Hardtke, D; Hardtke, R; Harenberg, T; Hauschildt, T; Helbing, K; Hellwig, M; Herquet, P; Hill, G C; Hodges, J; Hubert, D; Hughey, B; Hulth, P O; Hultqvist, K; Hundertmark, S; Jacobsen, J; Kampert, K H; Karle, A; Kelley, J L; Kestel, M; Kohnen, G; Köpke, L; Kowalski, M; Krasberg, M; Kühn, K; Leich, H; Leuthold, M; Liubarsky, I; Lundberg, J; Madsen, J; Marciniewski, P; Matis, H S; McParland, C P; Messarius, T; Minaeva, Y; Miocinovic, P; Morse, R; Munich, K; Nahnhauer, R; Nam, J W; Neunhoffer, T; Niessen, P; Nygren, D R; Ogelman, H; Olbrechts, P; Pérez de los Heros, C; Pohl, A C; Porrata, R; Price, P B; Przybylski, G T; Rawlins, K; Resconi, E; Rhode, W; Ribordy, M; Richter, S; Rodríguez-Martino, J; Sander, H G; Schinarakis, K; Schlenstedt, S; Schneider, D; Schwarz, R; Silvestri, A; Solarz, M; Spiczak, G M; Spiering, C; Stamatikos, M; Steele, D; Steffen, P; Stokstad, R G; Sulanke, K H; Taboada, I; Tarasova, O; Thollander, L; Tilav, S; Wagner, W; Walck, C; Walter, M; Wang, Y R; Wendt, C; Wiebusch, C; Wischnewski, R; Wissing, H; Woschnagg, K; Yodh, G

    2005-01-01

    The results of a search for point sources of high energy neutrinos in the northern hemisphere using data collected by AMANDA-II in the years 2000, 2001 and 2002 are presented. In particular, a comparison with the single-year result previously published shows that the sensitivity was improved by a factor of 2.2. The muon neutrino flux upper limits on selected candidate sources, corresponding to an E^{-2} neutrino energy spectrum, are included. Sky grids were used to search for possible excesses above the background of cosmic ray induced atmospheric neutrinos. This search reveals no statistically significant excess for the three years considered.

  5. Correlation of source rocks and oils in the Sespe oil field, Ventura County, California

    Energy Technology Data Exchange (ETDEWEB)

    Lillis, P.G. (Geological Survey, Lakewood, CO (United States)); Clark, M.S. (Colorado School of Mines, Golden (United States))

    1991-02-01

    The Sespe oil field in the central Ventura basin produces low sulfur (< 1%), intermediate gravity (23-32{degree} API) oil from Middle Eocene to Lower Miocene reservoirs in the upper plate of the San Cayetano thrust. Previous studies proposed the Eocene Cozy Dell, Matilija, and Juncal formations in the San Cayetano overthrust as the source rocks. Alternatively, the oils could be derived from the Miocene Monterey Formation in the subthrust. Gas chromatography and gas chromatography/mass spectrometry data are used to characterize and correlate the Sespe oils from comparison with bitumen extracts of the possible source rocks. The oils have pristane/phytane ratios of 1.3-1.6, bisnorhopane/hopane ratios of about 0.2, and relatively low amounts of diasteranes, oleanane, and C{sub 29} steranes. These data indicate that all of the oils belong to the same family and that variations in the API gravity are due to the degree of biodegradation. In addition, the sterane and triterpane distributions imply that the source organic matter is derived from marine phytoplankton and bacteria with a minor contribution from land plants. The Sespe oils do not correlate with the upper plate Eocene source rocks but correlate fairly well with the upper plate Eocene source rocks. Thus, a subthrust source is proposed. However, the Sespe oils have higher gravity and lower sulfur content than typical Monterey oils. The low sulfur content may result from the higher iron content, due to terrigenous input, of the Sespe field source rocks relative to other Monterey source rocks. Alternatively, the Sespe oils were expelled from the Monterey Formation at relatively high levels of thermal maturity.

  6. Polynuclear complex family of cobalt(II)/sulfonylcalixarene: one-pot synthesis of cluster salt [Co14(II)]+[Co4(II)]- and field-induced slow magnetic relaxation in a six-coordinate dinuclear cobalt(II)/sulfonylcalixarene complex.

    Science.gov (United States)

    Lamouchi, Meriem; Jeanneau, Erwann; Novitchi, Ghenadie; Luneau, Dominique; Brioude, Arnaud; Desroches, Cédric

    2014-01-06

    In this paper, we report the synthesis and description of a new family of polynuclear cobalt(II) complexes. Starting from the same initial compounds but varying the reaction time results in the formation of several new clusters, an original structure based on [Co14][Co4] clusters was obtained, representing the first one-pot synthesis of a cobalt aggregate salt reported in the literature. The synthesis and magnetic properties of these cobalt compounds are discussed. Three of them display a binuclear molecular structure (1-3) with two encapsulated Co(II) ions and show slow relaxation of magnetization at small applied magnetic field (Ueff = 10.7 K for 2 and Ueff = 20.3 K for 3), a characteristic of single-molecule-magnet materials.

  7. Numerical simulation of seepage flow field in groundwater source heat pump system and its influence on temperature field

    Institute of Scientific and Technical Information of China (English)

    Jihua HU; Yanjun ZHANG; Danyan DU; Gang WU; Ziwang YU; Chen WANG; Fuquan NI

    2008-01-01

    Energy utilization in the aquifers is a new technology closely related to development of heat pump technique. It is significant for the flow distribution to be predicted in the aquifer surrounding the Groundwater Source Heat Pump System (GSHPS). The authors presented a new concept of "flow transfixion" by analyzing general features of aquifers, and then discussed interaction of the flow transfixion with the heat transfixion, which has practical significance to projects. A numerical model of groundwater flow was established based on the basic tenets of water-heat transferring in the aquifer. On this basis the flow field and the temperature field of GSHPS for a site in Shenyang City were numerically simulated. The basis of the flow transfixion was obtained; it was discussed for the influence of the flow transfixion on the heat transfixion. To a certain extent, the study offers some reference for the projects' design of GSHP in the studied area.

  8. Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kim, June Young, E-mail: beacoolguy@snu.ac.kr; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr; Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2016-02-15

    The influence of magnetic filter field on plasma properties in the heating region has been investigated in a planar-type inductively coupled radio-frequency (RF) H{sup −} ion source. Besides filtering high energy electrons near the extraction region, the magnetic filter field is clearly observed to increase the electron temperature in the heating region at low pressure discharge. With increasing the operating pressure, enhancement of electron temperature in the heating region is reduced. The possibility of electron cyclotron resonance (ECR) heating in the heating region due to stray magnetic field generated by a filter magnet located at the extraction region is examined. It is found that ECR heating by RF wave field in the discharge region, where the strength of an axial magnetic field is approximately ∼4.8 G, can effectively heat low energy electrons. Depletion of low energy electrons in the electron energy distribution function measured at the heating region supports the occurrence of ECR heating. The present study suggests that addition of axial magnetic field as small as several G by an external electromagnet or permanent magnets can greatly increase the generation of highly ro-vibrationally excited hydrogen molecules in the heating region, thus improving the performance of H{sup −} ion generation in volume-produced negative hydrogen ion sources.

  9. Observations of the Hubble Deep Field with the Infrared Space Observatory; 2, Source detection and photometry

    CERN Document Server

    Goldschmidt, P

    1997-01-01

    We present positions and fluxes of point sources found in the Infrared Space Observatory (ISO) images of the Hubble Deep Field (HDF) at 6.7 and 15 micron. We have constructed algorithmically selected ``complete'' flux-limited samples of 19 sources in the 15 micron image, and 7 sources in the 6.7 micron image. The typical flux limit at 15 micron is 0.2 mJy and at 6.7 micron is 0.04 mJy. We have selected ``supplementary'' samples of 3 sources at 15 micron and 20 sources at 6.7 micron by eye. We discuss the completeness and reliability of the connected pixel source detect ion algorithm used, by comparing the intrinsic and estimated properties of simulated data, and also by estimating the noise properties of the real data. The most pessimistic estimate of the number of spurious sources in the ``complete'' samples is 1 at 15 micron and 2 at 6.7 micron, and in the ``supplementary'' lists is 1 at 15 micron and 5 at 6.7 micron.

  10. The 172 ks Chandra Exposure of the LALA Bootes Field: X-Ray Source Catalog

    Science.gov (United States)

    Wang, J. X.; Malhotra, S.; Rhoads, J. E.; Brown, M. J. I.; Dey, A.; Heckman, T. M.; Jannuzi, B. T.; Norman, C. A.; Tiede, G. P.; Tozzi, P.

    2004-01-01

    We present an analysis of a deep, 172 ks Chandra observation of the Large Area Lyman Alpha survey (LALA) Bootes field, obtained with the Advanced CCD Imaging Spectrometer (ACIS-I) on board the Chandra X-Ray Observatory. This is one of the deepest Chandra images of the extragalactic sky; only the 2 Ms Chandra Deep Field North (CDF-N) and 1 Ms Chandra Deep Field South (CDF-S) are substantially deeper. In this paper we present the X-ray source catalog obtained from this image, along with an analysis of source counts and optical identifications. The X-ray image is composed of two individual observations obtained in 2002 and reaches 0.5-2.0 and 2.0-10.0 keV flux limits of 1.5×10-16 and 1.0×10-15 ergs cm-2 s-1, respectively, for point sources near the aim point. A total of 168 X-ray sources were detected: 160 in the 0.5-7.0 keV band, 132 in the 0.5-2.0 keV band, and 111 in the 2.0-7.0 keV band. The X-ray source counts were derived and compared with those from other Chandra deep surveys; the hard X-ray source density of the LALA Bootes field is 33% higher than that of CDF-S at the flux level of 2.0×10-15 ergs cm-2 s-1, confirming the field-to-field variances of the hard-band source counts reported by previous studies. The deep exposure resolves >~72% of the 2.0-10.0 keV X-ray background. Our primary optical data are R-band imaging from the NOAO Deep Wide-Field Survey (NDWFS), with a limiting magnitude of R=25.7 (Vega, 3 σ, and 4" diameter aperture). We have found optical counterparts for 152 of the 168 Chandra sources (90%); 144 of these are detected in the R-band image, and eight have optical counterparts in other bands (either BW, V, I, or z'). Among the R-band nondetected sources, not more than 11 of them can possibly be at z>5, based on the hardness ratios of their X-ray emission and nondetections in bluer bands (BW, V). The majority (~76%) of the X-ray sources are found to have log(fX/fR) within 0.0+/-1 these are believed to be AGNs. Most of the X

  11. CANDELS Multi-wavelength Catalogs: Source Identification and Photometry in the CANDELS COSMOS Survey Field

    Science.gov (United States)

    Nayyeri, H.; Hemmati, S.; Mobasher, B.; Ferguson, H. C.; Cooray, A.; Barro, G.; Faber, S. M.; Dickinson, M.; Koekemoer, A. M.; Peth, M.; Salvato, M.; Ashby, M. L. N.; Darvish, B.; Donley, J.; Durbin, M.; Finkelstein, S.; Fontana, A.; Grogin, N. A.; Gruetzbauch, R.; Huang, K.; Khostovan, A. A.; Kocevski, D.; Kodra, D.; Lee, B.; Newman, J.; Pacifici, C.; Pforr, J.; Stefanon, M.; Wiklind, T.; Willner, S. P.; Wuyts, S.; Castellano, M.; Conselice, C.; Dolch, T.; Dunlop, J. S.; Galametz, A.; Hathi, N. P.; Lucas, R. A.; Yan, H.

    2017-01-01

    We present a multi-wavelength photometric catalog in the COSMOS field as part of the observations by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. The catalog is based on Hubble Space Telescope Wide Field Camera 3 (HST/WFC3) and Advanced Camera for Surveys observations of the COSMOS field (centered at R.A.: {10}{{h}}{00}{{m}}{28}{{s}}, Decl.: +02^\\circ 12\\prime {21}\\prime\\prime ). The final catalog has 38671 sources with photometric data in 42 bands from UV to the infrared (∼ 0.3{--}8 μ {{m}}). This includes broadband photometry from HST, CFHT, Subaru, the Visible and Infrared Survey Telescope for Astronomy, and Spitzer Space Telescope in the visible, near-infrared, and infrared bands along with intermediate- and narrowband photometry from Subaru and medium-band data from Mayall NEWFIRM. Source detection was conducted in the WFC3 F160W band (at 1.6 μm) and photometry is generated using the Template FITting algorithm. We further present a catalog of the physical properties of sources as identified in the HST F160W band and measured from the multi-band photometry by fitting the observed spectral energy distributions of sources against templates.

  12. The relationship between the occurrence of type II spicules and the dynamics of underlying magnetic fields

    Science.gov (United States)

    Yurchyshyn, V.; Abramenko, V.; Goode, P. R.

    2012-12-01

    Type II spicules are thought to be small-scale chromospheric up-flows. When observed against the solar disk they can be identified as rapid blue shifted events (or excursions, RBE, Rouppe van der Voort et al.). While their nature is being questioned and their associated driving mechanism remains elusive, these up-flows may be instrumental in the processes of coronal heating and solar wind. We use high resolution photospheric, chromospheric and magnetic field data from the New Solar Telescope operating at Big Bear Solar Observatory to further determine the properties of these events and refine the role that they may play. We find that the majority of RBEs, occurring around network clusters of bright points, can be linked to episodes of small flux emergence, in particular appearance of opposite polarity fields. Case studies further indicate that some of the RBEs appear to have kink and inverted "Y" shaped roots. The data thus suggest that magnetic reconnection may be responsible for at least some fraction of observed RBEs. We will present these observations in details and discuss possible implications.Sequence of H-alpha-0.075nm images spanning 7 min showing evolution of RBE activity near a cluster of network fields. The two yellow circles enclose the area where multipolar fields rapidly appeared. Comparing panels 19:05:11 UT and 19:05:55 UT one may notice that a new magnetic dipole and a dark jet appeared in the encircled area. The same is true about the encircled area in 19:07:26UT panel. The RBE activity ceased as soon as the the field of view was cleared from small-scale magnetic elements.

  13. A stress field in the vortex lattice in the type-II superconductor

    Directory of Open Access Journals (Sweden)

    Maruszewski, Bogdan

    2008-02-01

    Full Text Available Magnetic flux can penetrate a type-II superconductor in the form of Abrikosov vortices (also called flux lines, flux tubes, or fluxons, each carrying a quantum of magnetic flux. These tiny vortices of supercurrent tend to arrange themselves in a triangular and/or quadratic flux-line lattice, which is more or less perturbed by material inhomogeneities that pin the flux lines. Pinning is caused by imperfections of the crystal lattice, such as dislocations, point defects, grain boundaries, etc. Hence, a honeycomb-like pattern of the vortex array presents some mechanical properties. If the Lorentz force of interactions between the vortices is much bigger than the pinning force, the vortex lattice behaves elastically. So we assume that the pinning force is negligible in the sequel and we deal with soft vortices. The vortex motion in the vortex lattice and/or creep of the vortices in the vortex fluid is accompanied by energy dissipation. Hence, except for the elastic properties, the vortex field is also of a viscous character. The main aim of the paper is a formulation of a thermoviscoelastic stress - strain constitutive law consisted of coexistence of the ordered and disordered states of the vortex field. Its form describes an auxetic-like thermomechanical (anomalous property of the vortex field.

  14. Principles for transformation of scalp EEG from potential field into source distribution.

    Science.gov (United States)

    Hjorth, B

    1991-10-01

    Tracings representing simultaneously recorded values of EEG potentials from different positions on the scalp surface describe how the instantaneous potential field over the scalp surface changes with time. Each instantaneous distribution of potential can be seen as resulting from spatial integration of primary components into the potential field. These components may be derived by means of the reverse procedure: subjecting the data from the potential field to spatial differentiation as provided by the Laplacian source operator. The result is a "deblurred," i.e., a more differentiated, distribution of source components hypothetically associated with the generators of the potential field. The Laplacian source operator can be implemented as a linear combination of the instantaneous potential values, either by means of very simple electronic circuitry or in a computer. The linear combination is a standard operation in matrix algebra and is widely applied in signal processing. The formalism of matrix algebra simplifies a precise evaluation of the method in relation to conventional derivation techniques and provides further methods for analysis of the EEG data.

  15. Source fields reconstruction with 3D mapping by means of the virtual acoustic volume concept

    Science.gov (United States)

    Forget, S.; Totaro, N.; Guyader, J. L.; Schaeffer, M.

    2016-10-01

    This paper presents the theoretical framework of the virtual acoustic volume concept and two related inverse Patch Transfer Functions (iPTF) identification methods (called u-iPTF and m-iPTF depending on the chosen boundary conditions for the virtual volume). They are based on the application of Green's identity on an arbitrary closed virtual volume defined around the source. The reconstruction of sound source fields combines discrete acoustic measurements performed at accessible positions around the source with the modal behavior of the chosen virtual acoustic volume. The mode shapes of the virtual volume can be computed by a Finite Element solver to handle the geometrical complexity of the source. As a result, it is possible to identify all the acoustic source fields at the real surface of an irregularly shaped structure and irrespective of its acoustic environment. The m-iPTF method is introduced for the first time in this paper. Conversely to the already published u-iPTF method, the m-iPTF method needs only acoustic pressure and avoids particle velocity measurements. This paper is focused on its validation, both with numerical computations and by experiments on a baffled oil pan.

  16. Estimating sediment sources by multiple scale field measurements and fingerprinting using radionuclides

    Science.gov (United States)

    Onda, Y.; Mizugaki, S.; Nanko, K.; Asai, H.

    2006-12-01

    To study the fluvial sediment sources in forested watershed in Shikoku Island, Japan, field measurements and radionuclide analysis were conducted. The observation of erosion and runoff processes were conducted in variable scale in an unmanaged Japanese cypress (Chamaecyparis obtusa) plantation catchment with splash cup, runoff plot, Parshall flumes and integrated suspended sediment samplers for 5 months. For fingerprinting of suspended sediment, Cs-137 and Pb-210ex were determined by gamma-ray spectrometry for the potential sources as the surface soil of forest floor, stream bank and skid trail, eroded sediment by splash and runoff, and fluvial sediment. The concentrations of 1 Cs-137 and Pb-210ex of fluvial sediment are found to be varied in each sampling period. Therefore, there is temporal variation of suspended sediment sources in the watershed. The contribution of forest floor as suspended sediment source was estimated as high as -77 % by 137Cs. The results suggest that forest floor should be recognized as important source of fluvial sediment in this watershed. Based on the field measurements, splash detachment and overland flow occurred during rainfall event on the hillslope, eroded the surface soil on the forest floor, and transported fine particle downslope. Overland flow on the skid trails networks can transport the forest floor sediment into the stream channel, and can result in high contribution of forest floor soil to fluvial sediment in Japanese cypress catchment.

  17. Smooth and sharp creation of a pointlike source for a $(3+1)$-dimensional quantum field

    CERN Document Server

    Zhou, L J; Kunstatter, Gabor; Louko, Jorma

    2016-01-01

    We analyse the smooth and sharp creation of a pointlike source for a quantised massless scalar field in $(3+1)$-dimensional Minkowski spacetime, as a model for the breakdown of correlations that has been proposed to occur at the horizon of an evaporating black hole. After a smooth creation, the renormalised energy density $\\langle T_{00} \\rangle$ is well defined away from the source, but it is time dependent, and it is so large near the source that the total energy transmitted into the field during the source creation is infinite. In the sharp creation limit, $\\langle T_{00} \\rangle$ diverges everywhere in the causal future of the creation event, and so does the response of an Unruh-DeWitt detector that operates in the causal future of the creation event. The source creation is hence significantly more singular than the corresponding process in $1+1$ dimensions, and may be sufficiently singular to break down quantum correlations in the way which has been proposed to happen in the spacetime of an evaporating b...

  18. Solar axions as an energy source and modulator of the Earth magnetic field

    CERN Document Server

    Rusov, V D; Kudela, K; Mavrodiev, S Cht; Zelentsova, T N; Smolyar, V P; Merkotan, K K

    2010-01-01

    We show existence of strong negative correlation between the temporal variations of magnetic field toroidal component of the solar tachocline (the bottom of convective zone) and the Earth magnetic field (Y-component). The possibility that hypothetical solar axions, which can transform into photons in external electric or magnetic fields (the inverse Primakoff effect), can be the instrument by which the magnetic field of convective zone of the Sun modulates the magnetic field of the Earth is considered. We propose the axion mechanism of "solar dynamo-geodynamo" connection, where an energy of axions, which form in the Sun core, is modulated at first by the magnetic field of the solar tachocline zone (due to the inverse coherent Primakoff effect) and after that is absorbed in the liquid core of the Earth under influence of the terrestrial magnetic field, thereby playing the role of an energy source and a modulator of the Earth magnetic field. Within the framework of this mechanism new estimations of the strength...

  19. Coronal structure analysis based on the potential field source surface modeling and total solar eclipse observation

    Science.gov (United States)

    Muhamad, Johan; Mumtahana, Farahhati; Sutastio, Heri; Imaduddin, Irfan; Putri, Gerhana P.

    2016-11-01

    We constructed global coronal magnetic fields of the Sun during the Total Solar Eclipse (TSE) 9 March 2016 by using Potential Field Source Surface (PFSS) model. Synoptic photospheric magnetogram data from Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory (SDO) was used as a boundary condition to extrapolate the coronal magnetic fields of the Sun. This extrapolated structure was analyzed by comparing the alignment of the fields from the model with coronal structure from the observation. We also used observational data of coronal structure during the total solar eclipse to know how well the model agree with the observation. As a result, we could identify several coronal streamers which were produced by the large closed loops in the lower regime of the corona. This result verified that the PFSS extrapolation can be used as a tool to model the inner corona with several constraints. We also discussed how the coronal structure can be used to deduce the phase of the solar cycle.

  20. Behavior of moving plasma in solenoidal magnetic field in a laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, S., E-mail: ikeda.s.ae@m.titech.ac.jp [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0108 (Japan); Takahashi, K. [Department of Electrical Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2137 (Japan); Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Horioka, K. [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502 (Japan)

    2016-02-15

    In a laser ion source, a solenoidal magnetic field is useful to guide the plasma and to control the extracted beam current. However, the behavior of the plasma drifting in the magnetic field has not been well understood. Therefore, to investigate the behavior, we measured the plasma ion current and the total charge within a single pulse in the solenoid by changing the distance from the entrance of the solenoid to a detector. We observed that the decrease of the total charge along the distance became smaller as the magnetic field became larger and then the charge became almost constant with a certain magnetic flux density. The results indicate that the transverse spreading speed of the plasma decreased with increasing the field and the plasma was confined transversely with the magnetic flux density. We found that the reason of the confinement was not magnetization of ions but an influence induced by electrons.

  1. Behavior of moving plasma in solenoidal magnetic field in a laser ion source

    Science.gov (United States)

    Ikeda, S.; Takahashi, K.; Okamura, M.; Horioka, K.

    2016-02-01

    In a laser ion source, a solenoidal magnetic field is useful to guide the plasma and to control the extracted beam current. However, the behavior of the plasma drifting in the magnetic field has not been well understood. Therefore, to investigate the behavior, we measured the plasma ion current and the total charge within a single pulse in the solenoid by changing the distance from the entrance of the solenoid to a detector. We observed that the decrease of the total charge along the distance became smaller as the magnetic field became larger and then the charge became almost constant with a certain magnetic flux density. The results indicate that the transverse spreading speed of the plasma decreased with increasing the field and the plasma was confined transversely with the magnetic flux density. We found that the reason of the confinement was not magnetization of ions but an influence induced by electrons.

  2. Fourier method for recovering acoustic sources from multi-frequency far-field data

    Science.gov (United States)

    Wang, Xianchao; Guo, Yukun; Zhang, Deyue; Liu, Hongyu

    2017-03-01

    We consider an inverse source problem of determining a source term in the Helmholtz equation from multi-frequency far-field measurements. Based on the Fourier series expansion, we develop a novel non-iterative reconstruction method for solving the problem. A promising feature of this method is that it utilizes the data from only a few observation directions for each frequency. Theoretical uniqueness and stability analysis are provided. Numerical experiments are conducted to illustrate the effectiveness and efficiency of the proposed method in both two and three dimensions.

  3. Imaging Seismic Source Variations Using Back-Projection Methods at El Tatio Geyser Field, Northern Chile

    Science.gov (United States)

    Kelly, C. L.; Lawrence, J. F.

    2014-12-01

    During October 2012, 51 geophones and 6 broadband seismometers were deployed in an ~50x50m region surrounding a periodically erupting columnar geyser in the El Tatio Geyser Field, Chile. The dense array served as the seismic framework for a collaborative project to study the mechanics of complex hydrothermal systems. Contemporaneously, complementary geophysical measurements (including down-hole temperature and pressure, discharge rates, thermal imaging, water chemistry, and video) were also collected. Located on the western flanks of the Andes Mountains at an elevation of 4200m, El Tatio is the third largest geyser field in the world. Its non-pristine condition makes it an ideal location to perform minutely invasive geophysical studies. The El Jefe Geyser was chosen for its easily accessible conduit and extremely periodic eruption cycle (~120s). During approximately 2 weeks of continuous recording, we recorded ~2500 nighttime eruptions which lack cultural noise from tourism. With ample data, we aim to study how the source varies spatially and temporally during each phase of the geyser's eruption cycle. We are developing a new back-projection processing technique to improve source imaging for diffuse signals. Our method was previously applied to the Sierra Negra Volcano system, which also exhibits repeating harmonic and diffuse seismic sources. We back-project correlated seismic signals from the receivers back to their sources, assuming linear source to receiver paths and a known velocity model (obtained from ambient noise tomography). We apply polarization filters to isolate individual and concurrent geyser energy associated with P and S phases. We generate 4D, time-lapsed images of the geyser source field that illustrate how the source distribution changes through the eruption cycle. We compare images for pre-eruption, co-eruption, post-eruption and quiescent periods. We use our images to assess eruption mechanics in the system (i.e. top-down vs. bottom-up) and

  4. The potential use of diamond coated tungsten tips as a field ionisation source

    Energy Technology Data Exchange (ETDEWEB)

    Brown, A.; Prawer, S.; Legge, G.J.F.; Kostidis, L.I. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Tungsten tips are convenient for use in a high brightness gaseous phase field ionisation source. However, the lifetime of these tips is not adequate for practical use. The authors are investigating whether coating tungsten tips with diamond using Chemical Vapor Deposition (CVD) will improve the practicality of using these tips by an improvement in longevity of the source and/or an improvement in brightness due to the effects of the property of negative electron affinity which has been observed on CVD diamond. 1 ref.

  5. MOSFIRE and LDSS3 spectroscopy for an [O II] Blob at z = 1.18: gas outflow and energy source

    Energy Technology Data Exchange (ETDEWEB)

    Harikane, Yuichi; Ouchi, Masami; Yuma, Suraphong; Ono, Yoshiaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Rauch, Michael [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Nakajima, Kimihiko, E-mail: hari@icrr.u-tokyo.ac.jp [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2014-10-20

    We report our Keck/MOSFIRE and Magellan/Low-Dispersion Survey Spectrograph spectroscopy for an [O II] Blob, O II B 10, that is a high-z galaxy with spatially extended [O II] λλ3726, 3729 emission over 30 kpc recently identified by a Subaru large-area narrowband survey. The systemic redshift of O II B 10 is z = 1.18 securely determined with [O III] λλ4959, 5007 and Hβ emission lines. We identify Fe II λ2587 and Mg II λλ2796, 2804 absorption lines blueshifted from the systemic redshift by 80 ± 50 and 260 ± 40 km s{sup –1}, respectively, which indicates gas outflow from O II B 10 with the velocity of ∼80-260 km s{sup –1}. This outflow velocity is comparable with the escape velocity, 250 ± 140 km s{sup –1}, estimated under the assumption of a singular isothermal halo potential profile. Some fraction of the outflowing gas could escape from the halo of O II B 10, suppressing O II B 10's star-formation (SF) activity. We estimate a mass loading factor, η, that is a ratio of mass outflow rate to SF rate, and obtain η > 0.8 ± 0.1, which is relatively high compared with low-z starbursts including U/LIRGs and active galactic nuclei (AGNs). The major energy source of the outflow is unclear with the available data. Although no signature of AGNs is found in the X-ray data, O II B 10 falls in the AGN/star-forming composite region in the line diagnostic diagrams. It is possible that the outflow is powered by SF and a type-2 AGN with narrow FWHM emission line widths of 70-130 km s{sup –1}. This is the first detailed spectroscopic study of oxygen-line blobs that includes analyses of the escape velocity, the mass loading factor, and the presence of an AGN, and is a significant step to understanding the nature of oxygen-line blobs and the relation between gas outflow and SF quenching at high redshift.

  6. Exciton in vertically coupled type II quantum dots in threading magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza-Cantillo, J., E-mail: jhofry@gmail.com [Group of Investigation in Condensed Matter Theory, Universidad del Magdalena, Carrera 32 No 22-08, Santa Marta (Colombia); Universidad de la Guajira, Riohacha (Colombia); Escorcia-Salas, G. Elizabeth, E-mail: elizabethescorcia@gmail.com [Group of Investigation in Condensed Matter Theory, Universidad del Magdalena, Carrera 32 No 22-08, Santa Marta (Colombia); Mikhailov, I.D., E-mail: mikhail2811@gmail.com [Universidad Industrial de Santander, A. A. 678, Bucaramanga (Colombia); Sierra-Ortega, J., E-mail: jsierraortega@gmail.com [Group of Investigation in Condensed Matter Theory, Universidad del Magdalena, Carrera 32 No 22-08, Santa Marta (Colombia)

    2014-11-15

    We analyze the energy spectrum of a neutral exciton confined in a semiconductor heterostructure formed by two vertically coupled axially symmetrical type II quantum dots located close to each other. The electron in the structure is mainly located inside dots tunneling between them while the hole generally is placed in the exterior region close to the symmetry axis. Solutions of the Schrödinger equation are obtained by a variational separation of variables in the adiabatic limit. Numerical results are presented for the energies of bonding and anti-bonding lowest-lying of the exciton states and for the density of states for different InP/GaInP quantum dots' morphologies and the magnetic field strength values.

  7. Parameter sensitivity study of a Field II multilayer transducer model on a convex transducer

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2009-01-01

    .ResultsPredictions using the ZR give a pressure pulse error (PPE) and an intensity error (IE) of 32 % and 23 %, respectively, relative to the measured. Altering the piezoelectric permittivity +12 % from ZR decreases the PPE to 30 % and the IE to 2 % relative to the measured. Changing the stiffness constant of the lens -4......A multilayer transducer model for predicting a transducer impulse response has in earlier works been developed and combined with the Field II software. This development was tested on current, voltage, and intensity measurements on piezoceramics discs (Bæk et al. IUS 2008) and a convex 128 element...... ultrasound imaging transducer (Bæk et al. ICU 2009). The model benefits from its 1D simplicity and hasshown to give an amplitude error around 1.7‐2 dB. However, any prediction of amplitude, phase, and attenuation of pulses relies on the accuracy of manufacturer supplied material characteristics, which may...

  8. Reconstruction of an atmospheric tracer source in Fusion Field Trials: Analyzing resolution features

    Science.gov (United States)

    Singh, Sarvesh Kumar; Turbelin, Gregory; Issartel, Jean-Pierre; Kumar, Pramod; Feiz, Amir Ali

    2015-06-01

    Reconstruction of unknown atmospheric releases using measured concentrations is an ill-posed inverse problem. Due to insufficient measurements and dispersion model uncertainties, reliable interpretation of a retrieved source is limited by lack of resolution, nonuniqueness, and instability in the inverse solution. The study presents an optimality analysis, in terms of resolution, stability, and reliability, of an inverse solution given by a recently proposed inversion technique, called as renormalization. The inversion technique is based on an adjoint source-receptor framework and construction of a weight function which interprets a priori information about the unknown release apparent to the monitoring network. The properties of weight function provide a perfect data resolution, maximum model resolution, and minimum variance (or stability) for the retrieved source. The reliability of the retrieved source is interpreted in view of the information derived from the geometry of the monitoring network. The inversion technique and resolution features are evaluated for a point source reconstruction using measurements from a recent dispersion experiment (Fusion Field Trials 2007) conducted at Dugway Proving Ground, Utah. With the real measurements, the point release is reconstructed within an average distance of 23 m from the true release where the average distance of the nearest receptor from the true source was 32 m. In all the trials, the point release is retrieved within 3-60 m Euclidean distance from their true location. The source strength is retrieved within a factor of 1.5 to the true release mass. The posterior uncertainty in the release parameters is observed to be within 20% of their mean value. The source localization features are resolved to its maximum extent feasible with the design of the monitoring network. The sensitivity studies are conducted to highlight the importance of receptors reporting zero concentration measurements and variations in the

  9. Dipole source analysis for readiness potential and field using simultaneously measured EEG and MEG signals.

    Science.gov (United States)

    Mideksa, K G; Hellriegel, H; Hoogenboom, N; Krause, H; Schnitzler, A; Deuschl, G; Raethjen, J; Heute, U; Muthuraman, M

    2013-01-01

    Various source localization techniques have indicated the generators of each identifiable component of movement-related cortical potentials, since the discovery of the surface negative potential prior to self-paced movement by Kornhuber and Decke. Readiness potentials and fields preceding self-paced finger movements were recorded simultaneously using multichannel electroencephalography (EEG) and magnetoencephalography (MEG) from five healthy subjects. The cortical areas involved in this paradigm are the supplementary motor area (SMA) (bilateral), pre-SMA (bilateral), and contralateral motor area of the moving finger. This hypothesis is tested in this paper using the dipole source analysis independently for only EEG, only MEG, and both combined. To localize the sources, the forward problem is first solved by using the boundary-element method for realistic head models and by using a locally-fitted-sphere approach for spherical head models consisting of a set of connected volumes, typically representing the scalp, skull, and brain. In the source reconstruction it is to be expected that EEG predominantly localizes radially oriented sources while MEG localizes tangential sources at the desired region of the cortex. The effect of MEG on EEG is also observed when analyzing both combined data. When comparing the two head models, the spherical and the realistic head models showed similar results. The significant points for this study are comparing the source analysis between the two modalities (EEG and MEG) so as to assure that EEG is sensitive to mostly radially orientated sources while MEG is only sensitive to only tangential sources, and comparing the spherical and individual head models.

  10. Integral Field Spectroscopy of Massive Young Stellar Objects in the N113 H\\,{\\sc ii} Region in the Large Magellanic Cloud

    CERN Document Server

    Ward, J L; van Loon, J Th; Sewilo, M

    2015-01-01

    The \\textit{Spitzer} SAGE survey has allowed the identification and analysis of significant samples of Young Stellar Object (YSO) candidates in the Large Magellanic Cloud (LMC). However the angular resolution of \\textit{Spitzer} is relatively poor meaning that at the distance of the LMC, it is likely that many of the \\textit{Spitzer} YSO candidates in fact contain multiple components. We present high resolution \\textit{K}-band integral field spectroscopic observations of the three most prominent massive YSO candidates in the N113 H\\,{\\sc ii} region using VLT/SINFONI. We have identified six \\textit{K}-band continuum sources within the three \\textit{Spitzer} sources and we have mapped the morphology and velocity fields of extended line emission around these sources. Br$\\gamma$, He\\,{\\sc i} and H$_2$ emission is found at the position of all six \\textit{K}-band sources; we discuss whether the emission is associated with the continuum sources or whether it is ambient emission. H$_2$ emission appears to be mostly a...

  11. Characterization of metal oxide field-effect transistors for first helical tomotherapy Hi-Art II unit in India

    Directory of Open Access Journals (Sweden)

    Kinhikar Rajesh

    2009-01-01

    Full Text Available Purpose : To characterize metal oxide semiconductor field-effect transistors (MOSFETs for a 6-MV photon beam with a first helical tomotherapy Hi-Art II unit in India. Materials and Methods : Standard sensitivity MOSFETs were first calibrated and then characterized for reproducibility, field size dependence, angular dependence, fade effects, and temperature dependence. The detector sensitivity was estimated for static as well as rotational modes for three jaw settings (1.0 cm × 40 cm, 2.5 cm × 40 cm, and 5 cm × 40 cm at 1.5-cm depth with a source-to-axis distance (SAD of 85 cm in virtual water slabs. The A1SL ion chamber and thermoluminescence dosimeters (TLDs were used to compare the results. Results : No significant difference was found in the detector sensitivity for static and rotational procedures. The average detector sensitivity for static procedures was 1.10 mV/cGy (SD 0.02 while it was 1.12 mV/cGy (SD 0.02 for rotational procedures. The average detector sensitivity found was the same within the experimental uncertainty for static and rotational dose deliveries. The MOSFET reading was consistent and its reproducibility was excellent (+0.5% while there was no significant dependence of field size. The angular dependence of less than 1.0% was observed. There was negligible fading effect of the MOSFET. The MOSFET response was found independent of temperature in the range 18°-30°. The ion chamber readings were assumed to be a reference for the estimation of the MOSFET calibration factor. The ion chamber and the TLD were in good agreement (+2% with each other. Conclusion : This study deals only with the measurements and calibration performed on the surface of the phantom. MOSFET was calibrated and validated for phantom surface measurements for a 6-MV photon beam generated by a tomotherapy machine. The sensitivity of the detector was the same for both modes of treatment delivery with tomotherapy. The performance of the MOSFET was validated

  12. Acoustic radiation field of the truncated parametric source generated by a piston radiator model and experiment

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiaoliang; ZHU Zhemin; DU Gonghuan; TANG Haiqing; LI Shui; MIAO Rongxing

    2001-01-01

    A theoretical model is presented to describe the parametric acoustic field generated by a piston radiator. In the model, the high-frequency primary wave interaction region that is truncated by a low-pass acoustic filter can be viewed as a cylindrical source within the Rayleigh distance of the piston. When the radius of the piston is much smaller than the length of the parametric region, this model is reduced to the Berketey's End-Fire Line Array model. Comparison between numerical calculations and experimental measurement show that the generated parametric sound field (especially near the axis) agrees well with the experiment results.

  13. Field-induced slow magnetic relaxation in a six-coordinate mononuclear cobalt(II) complex with a positive anisotropy.

    Science.gov (United States)

    Vallejo, Julia; Castro, Isabel; Ruiz-García, Rafael; Cano, Joan; Julve, Miguel; Lloret, Francesc; De Munno, Giovanni; Wernsdorfer, Wolfgang; Pardo, Emilio

    2012-09-26

    The novel mononuclear Co(II) complex cis-[Co(II)(dmphen)(2)(NCS)(2)]·0.25EtOH (1) (dmphen = 2,9-dimethyl-1,10-phenanthroline) features a highly rhombically distorted octahedral environment that is responsible for the strong positive axial and rhombic magnetic anisotropy of the high-spin Co(II) ion (D = +98 cm(-1) and E = +8.4 cm(-1)). Slow magnetic relaxation effects were observed for 1 in the presence of a dc magnetic field, constituting the first example of field-induced single-molecule magnet behavior in a mononuclear six-coordinate Co(II) complex with a transverse anisotropy energy barrier.

  14. The multiplicity of 250-$\\mu$m Herschel sources in the COSMOS field

    CERN Document Server

    Scudder, Jillian M; Hurley, Peter D; Griffin, Matt; Sargent, Mark T; Scott, Douglas; Wang, Lingyu; Wardlow, Julie L

    2016-01-01

    We investigate the multiplicity of extragalactic sources detected by the Herschel Space Observatory in the COSMOS field. Using 3.6- and 24-$\\mu$m catalogues, in conjunction with 250-$\\mu$m data from Herschel, we seek to determine if a significant fraction of Herschel sources are composed of multiple components emitting at 250 $\\mu$m. We use the XID+ code, using Bayesian inference methods to produce probability distributions of the possible contributions to the observed 250-$\\mu$m flux for each potential component. The fraction of Herschel flux assigned to the brightest component is highest for sources with total 250-$\\mu$m fluxes < 45 mJy; however, the flux in the brightest component is still highest in the brightest Herschel sources. The faintest 250-$\\mu$m sources (30-45 mJy) have the majority of their flux assigned to a single bright component; the second brightest component is typically significantly weaker, and contains the remainder of the 250-$\\mu$m source flux. At the highest 250-$\\mu$m fluxes (45-...

  15. BLAST Observations of the South Ecliptic Pole field: Number Counts and Source Catalogs

    CERN Document Server

    Valiante, Elisabetta; Bock, James; Braglia, Filiberto; Chapin, Edward; Devlin, Mark Joseph; Griffin, Matthew; Gundersen, Joshua; Halpern, Mark; Hargrave, Peter; Hughes, David; Klein, Jeff; Marsden, Gaelen; Mauskopf, Philip; Netterfield, Calvin; Olmi, Luca; Pascale, Enzo; Patanchon, Guillaume; Rex, Marie; Scott, Douglas; Scott, Kimberly; Semisch, Christopher; Stabenau, Hans; Thomas, Nicholas; Truch, Matthew; Tucker, Carole; Tucker, Gregory; Viero, Marco; Wiebe, Donald

    2010-01-01

    We present results from a survey carried out by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) on a 9 deg^2 field near the South Ecliptic Pole at 250, 350 and 500 {\\mu}m. The median 1{\\sigma} depths of the maps are 36.0, 26.4 and 18.4 mJy, respectively. We apply a statistical method to estimate submillimeter galaxy number counts and find that they are in agreement with other measurements made with the same instrument and with the more recent results from Herschel/SPIRE. Thanks to the large field observed, the new measurements give additional constraints on the bright end of the counts. We identify 132, 89 and 61 sources with S/N>4 at 250, 350, 500 {\\mu}m, respectively and provide a multi-wavelength combined catalog of 232 sources. The new BLAST maps and catalogs are available publicly at http://blastexperiment.info.

  16. Second-order spatial correlation in the far-field: Comparing entangled and classical light sources

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Erfeng, E-mail: efzhang@163.com; Liu, Weitao; Lin, Huizu; Chen, Pingxing

    2016-02-15

    Highlights: • Second-order spatial correlation with entangled and classical light in the far-field is investigated. • The role of photon statistics and detection mode in the second-order spatial correlation are discussed. • The difference of second-order spatial correlation with entangled and classical light sources is deduced. - Abstract: We consider second-order spatial correlation with entangled and classical light in the far-field. The quantum theory of second-order spatial correlation is analyzed, and the role of photon statistics and detection mode in the second-order spatial correlation are discussed. Meanwhile, the difference of second-order spatial correlation with entangled and classical light sources is deduced.

  17. Bright and durable field emission source derived from refractory taylor cones

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, Gregory

    2016-12-20

    A method of producing field emitters having improved brightness and durability relying on the creation of a liquid Taylor cone from electrically conductive materials having high melting points. The method calls for melting the end of a wire substrate with a focused laser beam, while imposing a high positive potential on the material. The resulting molten Taylor cone is subsequently rapidly quenched by cessation of the laser power. Rapid quenching is facilitated in large part by radiative cooling, resulting in structures having characteristics closely matching that of the original liquid Taylor cone. Frozen Taylor cones thus obtained yield desirable tip end forms for field emission sources in electron beam applications. Regeneration of the frozen Taylor cones in-situ is readily accomplished by repeating the initial formation procedures. The high temperature liquid Taylor cones can also be employed as bright ion sources with chemical elements previously considered impractical to implement.

  18. Developing and using the field emitter as a high intensity electron source

    Science.gov (United States)

    Charbonnier, Francis

    1996-03-01

    In the 1940's, Erwin Müller dominated field emission research. The 50's and 60's saw considerable growth in the number of scientists interested in field emission. While many made important contributions, three persons stood out who had different talents and interests. First and foremost: Erwin Müller, a very innovative, creative and skilled inventor and experimentalist. Second: Robert Gomer, equally adept at theory and experiment, with a unique mastery of fundamental physics concepts. Third: Walter Dyke, who was intrigued by the unique properties of field emission and resolved to develop field emission cathodes as high performance electron sources for a variety of electron beam devices. This paper summarizes Dyke's work at Linfield College, Linfield Research Institute and Field Emission Corporation from 1948 to 1972. However, while Dyke established a solid foundation for useful field emission cathodes and investigated several devices, particularly in microwaves, electron optics and flash radiography, he was unable to complete his work and produce commercial devices, except for flash radiography. Many groups have pursued this work in recent years, sometimes with great success. This paper briefly summarizes current work on field emission cathodes and device applications, as this puts Dyke's work in better perspective and adds to its significance.

  19. Variation in energy stored and dissipated in type-II superconductor in applied ac magnetic field with relative phase of two sinusoidal components of the field

    Science.gov (United States)

    Janů, Zdeněk; Chagovets, Tymofiy

    2017-01-01

    We show that both the energy stored and dissipated by a system with hysteretic nonlinearity in an applied field varies with the relative phase of the sinusoidal components of the field, even if the magnitude of these components, and thus an effective value of the field, are kept constant. The explored system is a type-II superconductor in the critical state subjected to a time varying applied magnetic field. Complete analytical expressions for hysteresis loops, determined from basic physical phenomena, are known for this system. A theoretically predicted variation in the energy is in good agreement with our experimental measurements.

  20. Assessment of control technology for stationary sources. Volume II: control technology data tables. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Minicucci, D.; Herther, M.; Babb, L.; Kuby, W.

    1980-02-01

    This report, the Control Technology Data Tables, is the second volume of the three-volume final report for the contract. It presents in tabular format, qualitative descriptions of control options for the various sources and quantitative information on control technology cost, efficiency, reliability, energy consumption, other environmental impacts and application status. Also included is a code list which classifies the stationary sources examined by industry, process, and emission source.

  1. Main Magnetic Focus Ion Source: II. The first investigations at 10 keV

    CERN Document Server

    Ovsyannikov, V P

    2015-01-01

    The basic principles of design for the compact ion source of new generation are presented. The device uses the local ion trap created by the axial electron beam rippled in a thick magnetic lens. In accordance with this feature, the ion source is given the name main magnetic focus ion source. The experimental evidences for the production of Ir$^{59+}$, Xe$^{44+}$, and Ar$^{16+}$ ions are obtained. The control over depth of the local ion trap is shown to be feasible.

  2. Non ionizing radiations Sources, fields of application, problem issues and normatives

    CERN Document Server

    Raganella, L

    1988-01-01

    The purpose of this paper is briefly to review radiation sources, in work and life places, and national standards, proposed or enforced in different countries, with particular reference to ELF. RF and MW electromagnetic fields. It is aimed to give a help to qualitative valutation on the work we can carry out for the development of an effective health protection of workers and general public.

  3. Ion Source for Neutral beam injection meant for plasma and magnetic field diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Vainionpaa, Jaakko Hannes; Leung, Ka Ngo; Gough, Richard A.; Kwan, Joe W.; Levinton, Fred

    2007-06-01

    At the Lawrence Berkeley National Laboratory (LBNL) a diagnostic neutral beam injection system for measuring plasma parameters, flow velocity, and local magnetic field is being developed. The systems is designed to have a 90 % proton fraction and small divergence with beam current at 5-6 A and a pulse length of {approx}1 s occurring once every 1-2 min. The ion source needs to generate uniform plasma over a large (8 cm x 5 cm) extraction area. For this application, we have compared RF driven multicusp ion sources operating with either an external or an internal antenna in similar ion source geometry. The ion beam will be made of an array of six sheet-shaped beamlets. The design is optimized using computer simulation programs.

  4. A Volt-Second Source for Calibration of Integrator in a Pulsed Field Magnetometer

    Institute of Scientific and Technical Information of China (English)

    LIN An-Li; HE Jian; ZHANG Yue; John Dudding; Michael Hall

    2007-01-01

    A volt-second (Vs) source intended for absolutely calibrating the integrator in a pulsed field magnetometer (PFM) is designed and proven to be with accurate rising and falling edges and reasonable lower uncertainty. A comparison experiment shows that the difference between the magnetic fluxes generated respectively by the Vs source and the mutual inductor is within ±0.04%. The PFM is then calibrated in an absolute way of the Vs source. The calibrated PFM gives the measured results in good agreement with a static BH tracer supplied by National Institute of Metrology of China and provides a convenient way of studying the effect of mathematic process on the dynamic measuring curve of PFMs.

  5. A complete census of Herschel-detected infrared sources within the HST Frontier Fields

    CERN Document Server

    Rawle, T D; Egami, E; Pérez-González, P G; Boone, F; Clement, B; Ivison, R J; Richard, J; Rujopakarn, W; Valtchanov, I; Walth, G; Weiner, B; Blain, A W; Dessauges-Zavadsky, M; Kneib, J -P; Lutz, D; Rodighiero, G; Schaerer, D; Smail, I

    2015-01-01

    We present a complete census of all 263 Herschel-detected sources within the HST Frontier Fields (HFF), a deep multi-filter HST programme covering six massive lensing clusters. We provide a robust legacy catalogue of Herschel fluxes, primarily based on imaging from the Herschel Lensing Survey (HLS) and PEP/HerMES Key Programmes. Photometry is derived via a simultaneous PSF-fit using priors from archival Spitzer imaging. We optimally combine Herschel, Spitzer and WISE infrared (IR) photometry with data from HST, VLA and ground-based observatories, identifying optical counterparts to gain source redshifts. Hence for each Herschel-detected source we also present magnification factor (mu), intrinsic IR luminosity and characteristic dust temperature, providing a comprehensive view of dust-obscured star formation within the HFF. We demonstrate the utility of our catalogues through an exploratory overview of HST morphologies for the IR-bright population. In particular we briefly describe the highest redshift (z>2.5)...

  6. NuSTAR Hard X-ray Survey of the Galactic Center Region II: X-ray Point Sources

    CERN Document Server

    Hong, JaeSub; Hailey, Charles J; Nynka, Melania; Zhang, Shuo; Gotthelf, Eric; Fornasini, Francesca M; Krivonos, Roman; Bauer, Franz; Perez, Kerstin; Tomsick, John A; Bodaghee, Arash; Chiu, Jeng-Lun; Clavel, Maïca; Stern, Daniel; Grindlay, Jonathan E; Alexander, David M; Aramaki, Tsuguo; Baganoff, Frederick K; Barret, David; Barrière, Nicolas; Boggs, Steven E; Canipe, Alicia M; Christensen, Finn E; Craig, William W; Desai, Meera A; Forster, Karl; Giommi, Paolo; Grefenstette, Brian W; Harrison, Fiona A; Hong, Dooran; Hornstrup, Allan; Kitaguchi, Takao; Koglin, Jason E; Madsen, Kristen K; Mao, Peter H; Miyasaka, Hiromasa; Perri, Matteo; Pivovaroff, Michael J; Puccetti, Simonetta; Rana, Vikram; Westergaard, Niels J; Zhang, William W; Zoglauer, Andreas

    2016-01-01

    We present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3-79 keV) X-ray point sources in a 0.6 deg^2 region around Sgr A* with a total exposure of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. We identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of ~4 x and ~8 x 10^32 erg s^-1 at the GC (8 kpc) in the 3-10 and 10-40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources ...

  7. Two-Dimensional Far Field Source Locating Method with Nonprior Velocity

    Directory of Open Access Journals (Sweden)

    Qing Chen

    2016-01-01

    Full Text Available Relative position of seismic source and sensors has great influence on locating accuracy, particularly in far field conditions, and the accuracy will decrease seriously due to limited calculation precision and prior velocity error. In order to improve the locating accuracy of far field sources by isometric placed sensors in a straight line, a new locating method with nonprior velocity is proposed. After exhaustive research, this paper states that the hyperbola which is used for locating will be very close to its asymptote when seismic source locates in far field of sensors; therefore, the locating problem with prior velocity is equivalent to solving linear equations and the problem with nonprior velocity is equivalent to a nonlinear optimization problem with respect to the unknown velocity. And then, this paper proposed a new locating method based on a one-variable objective function with respect to the unknown velocity. Numerical experiments show that the proposed method has faster convergence speed, higher accuracy, and better stability.

  8. NEAR-FIELD SOURCE LOCALIZATION METHOD AND APPLICATION USING THE TIME REVERSAL MIRROR TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    Fu Yongqing; Jiang Yulei; Liu Zhanya

    2011-01-01

    In order to develop the acoustic keyboard for Personal Computer (PC),it is necessary to seek high-precision near-field source localization algorithm for identifying the keyboard characters.First of all,the focusing property of Time Reversal Mirror (TRM) is introduced,and then a mathematical model of microphone array receiving typing sound is established according to the realization of acoustic keyboard from which the TRM localization algorithm is carried out.The results through computer simulation show that the localization Root Mean Square Error (RMSE) performance of the algorithm can reach 10-3,which demonstrates that the algorithm possesses a high accuracy for the actual near-field acoustic source localization,with potential of developing the computer acoustic keyboard.Furthermore,for the purpose of testing its effect on actual near-field source localization,we organize three experiments for acoustic keyboard characters localization.The experiment results show that the positioning error of TRM algorithm is less than 1 cm within a provided acoustic keyboard region.This will provide theoretical guidance for the further research of computer acoustic keyboard.

  9. Field and synthetic experiments for virtual source crosswell tomography in vertical wells: Perth Basin, Western Australia

    Science.gov (United States)

    Almalki, Majed; Harris, Brett; Dupuis, J. Christian

    2013-11-01

    It is common for at least one monitoring well to be located proximally to a production well. This presents the possibility of applying crosswell technologies to resolve a range of earth properties between the wells. We present both field and synthetic examples of dual well walk-away vertical seismic profiling in vertical wells and show how the direct arrivals from a virtual source may be used to create velocity images between the wells. The synthetic experiments highlight the potential of virtual source crosswell tomography where large numbers of closely spaced receivers can be deployed in multiple wells. The field experiment is completed in two monitoring wells at an aquifer storage and recovery site near Perth, Western Australia. For this site, the crosswell velocity distribution recovered from inversion of travel times between in-hole virtual sources and receivers is highly consistent with what is expected from sonic logging and detailed zero-offset vertical seismic profiling. When compared to conventional walkaway vertical seismic profiling, the only additional effort required to complete dual-well walkaway vertical seismic profiling is the deployment of seismic sensors in the second well. The significant advantage of virtual source crosswell tomography is realised where strong near surface heterogeneity results in large travel time statics.

  10. Neutron calibration field of bare {sup 252}Cf source in Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Le, Ngoc Thiem; Tran, Hoai Nam; Nguyen, Khai Tuan [Institute for Nuclear Science and Technology, Hanoi (Viet Nam); Trinh, Glap Van [Institute of Research and Development, Duy Tan University, Da Nang (Viet Nam)

    2017-02-15

    This paper presents the establishment and characterization of a neutron calibration field using a bare {sup 252}Cf source of low neutron source strength in Vietnam. The characterization of the field in terms of neutron flux spectra and neutron ambient dose equivalent rates were performed by Monte Carlo simulations using the MCNP5 code. The anisotropy effect of the source was also investigated. The neutron ambient dose equivalent rates at three reference distances of 75, 125, and 150 cm from the source were calculated and compared with the measurements using the Aloka TPS-451C neutron survey meters. The discrepancy between the calculated and measured values is found to be about 10%. To separate the scattered and the direct components from the total neutron flux spectra, an in-house shadow cone of 10% borated polyethylene was used. The shielding efficiency of the shadow cone was estimated using the MCNP5 code. The results confirmed that the shielding efficiency of the shadow cone is acceptable.

  11. Field portable low temperature porous layer open tubular cryoadsorption headspace sampling and analysis part II: Applications.

    Science.gov (United States)

    Harries, Megan; Bukovsky-Reyes, Santiago; Bruno, Thomas J

    2016-01-15

    This paper details the sampling methods used with the field portable porous layer open tubular cryoadsorption (PLOT-cryo) approach, described in Part I of this two-part series, applied to several analytes of interest. We conducted tests with coumarin and 2,4,6-trinitrotoluene (two solutes that were used in initial development of PLOT-cryo technology), naphthalene, aviation turbine kerosene, and diesel fuel, on a variety of matrices and test beds. We demonstrated that these analytes can be easily detected and reliably identified using the portable unit for analyte collection. By leveraging efficiency-boosting temperature control and the high flow rate multiple capillary wafer, very short collection times (as low as 3s) yielded accurate detection. For diesel fuel spiked on glass beads, we determined a method detection limit below 1 ppm. We observed greater variability among separate samples analyzed with the portable unit than previously documented in work using the laboratory-based PLOT-cryo technology. We identify three likely sources that may help explain the additional variation: the use of a compressed air source to generate suction, matrix geometry, and variability in the local vapor concentration around the sampling probe as solute depletion occurs both locally around the probe and in the test bed as a whole. This field-portable adaptation of the PLOT-cryo approach has numerous and diverse potential applications.

  12. Influence of the Galactic Gravitational Field on the Positional Accuracy of Extragalactic Sources

    Science.gov (United States)

    Larchenkova, Tatiana I.; Lutovinov, Alexander A.; Lyskova, Natalya S.

    2017-01-01

    We investigate the influence of random variations of the Galactic gravitational field on the apparent celestial positions of extragalactic sources. The basic statistical characteristics of a stochastic process (first-order moments, an autocorrelation function and a power spectral density) are used to describe a light ray deflection in a gravitational field of randomly moving point masses as a function of the source coordinates. We map a 2D distribution of the standard deviation of the angular shifts in positions of distant sources (including reference sources of the International Celestial Reference Frame) with respect to their true positions. For different Galactic matter distributions the standard deviation of the offset angle can reach several tens of μas (microarcsecond) toward the Galactic center, decreasing down to 4–6 μas at high galactic latitudes. The conditional standard deviation (“jitter”) of 2.5 μas is reached within 10 years at high galactic latitudes and within a few months toward the inner part of the Galaxy. The photometric microlensing events are not expected to be disturbed by astrometric random variations anywhere except the inner part of the Galaxy as the Einstein–Chvolson times are typically much shorter than the jittering timescale. While a jitter of a single reference source can be up to dozens of μas over some reasonable observational time, using a sample of reference sources would reduce the error in relative astrometry. The obtained results can be used for estimating the physical upper limits on the time-dependent accuracy of astrometric measurements.

  13. Separation of radiated sound field components from waves scattered by a source under non-anechoic conditions

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn

    2010-01-01

    A method of estimating the sound field radiated by a source under non-anechoic conditions has been examined. The method uses near field acoustic holography based on a combination of pressure and particle velocity measurements in a plane near the source for separating outgoing and ingoing wave...... components. The outgoing part of the sound field is composed of both radiated and scattered waves. The method compensates for the scattered components of the outgoing field on the basis of the boundary condition of the problem, exploiting the fact that the sound field is reconstructed very close...... to the source. Thus the radiated free-field component is estimated simultaneously with solving the inverse problem of reconstructing the sound field near the source. The method is particularly suited to cases in which the overall contribution of reflected sound in the measurement plane is significant....

  14. Mapping Field Trials II Mendocino Volcano Field I and II (EX0905, EM302) on NOAA Ship Okeanos Explorer in North Pacific Ocean

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goals of this field trial cruise are to test use of EX mapping sensors to characterize complex geological areas (i.e. volcanic field) and develop protocols to...

  15. Vortex and characteristics of prestrained type-II deformable superconductors under magnetic fields

    Science.gov (United States)

    Ma, Zeling; Wang, Xingzhe; Zhou, Youhe

    2016-04-01

    Based on the time-dependent Ginzburg-Landau (TDGL) theory and the linear deformation theory, we present a numerical investigation of magnetic vortex characteristics of a type-II deformable superconductor with prestrain. The effect of prestrain on the wave function, vortex dynamics and energy density of a superconducting film is analyzed by solving the nonlinear TDGL equations in the presence of magnetic field. The results show that the prestrain has a remarkable influence on the magnetic vortex distribution and the vortex dynamics, as well as value of wave function of the superconductor. The different prestrains, i.e., pre-given compression and tension strains, result in dissimilar characteristics on a half-plane of deformable superconductor in an applied magnetic field, and the vortex distribution and entrance in a two dimensional superconducting film. The studies demonstrated that the compression prestrain may speed up the vortexes entering into the region of the superconducting film and increases the vortex number in comparison with those of free-prestrain case, while the tension prestrain shows the reversal features. The energy density and spectrum in the superconductor are further demonstrated numerically and discussed. The present investigation is an attempt to give insight into the superconductivity and electromagnetic characteristics taking into account the elastic deformation in superconductors.

  16. THE WIDE-AREA ENERGY STORAGE AND MANAGEMENT SYSTEM PHASE II Final Report - Flywheel Field Tests

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ning; Makarov, Yuri V.; Weimar, Mark R.; Rudolph, Frank; Murthy, Shashikala; Arseneaux, Jim; Loutan, Clyde; Chowdhury, S.

    2010-08-31

    This research was conducted by Pacific Northwest National Laboratory (PNNL) operated for the U.S. department of Energy (DOE) by Battelle Memorial Institute for Bonneville Power Administration (BPA), California Institute for Energy and Environment (CIEE) and California Energy Commission (CEC). A wide-area energy management system (WAEMS) is a centralized control system that operates energy storage devices (ESDs) located in different places to provide energy and ancillary services that can be shared among balancing authorities (BAs). The goal of this research is to conduct flywheel field tests, investigate the technical characteristics and economics of combined hydro-flywheel regulation services that can be shared between Bonneville Power Administration (BPA) and California Independent System Operator (CAISO) controlled areas. This report is the second interim technical report for Phase II of the WAEMS project. This report presents: 1) the methodology of sharing regulation service between balancing authorities, 2) the algorithm to allocate the regulation signal between the flywheel and hydro power plant to minimize the wear-and-tear of the hydro power plants, 3) field results of the hydro-flywheel regulation service (conducted by the Beacon Power), and 4) the performance metrics and economic analysis of the combined hydro-flywheel regulation service.

  17. Geomagnetic Field Variations as Determined from Bulgarian Archaeomagnetic Data. Part II: The Last 8000 Years

    Science.gov (United States)

    Kovacheva, Mary; Jordanova, Neli; Karloukovski, Vassil

    The knowledge about past secular variations of the geomagnetic field is achieved on the basis of archaeomagnetic researches of which the Bulgarian studies form an extended data set. In Part I (Kovacheva and Toshkov, 1994), the methodology used in the Sofia palaeomagnetic laboratory was described and the secular variation curves for the last 2000 years were shown. In Part II (this paper), the basic characteristics of the prehistoric materials used in the archaeomagnetic studies are emphasised, particularly in the context of the rock magnetic studies used in connection with palaeointensity determinations. The results of magnetic anisotropy studies of the prehistoric ovens and other fired structures are summarised, including the anisotropy correction of the palaeointensity results for prehistoric materials, different from bricks and pottery. Curves of the direction and intensity of the geomagnetic field during the last 8000 years in Bulgaria are given. The available directional and intensity values have been used to calculate the variation curve of the virtual dipole moment (VDM) for the last 8000 years based on different time interval averages. The path of virtual geomagnetic pole (VGP) positions is discussed.

  18. Structure and physics of solar faculae. II - The non-thermal velocity field above faculae

    Science.gov (United States)

    Mouradian, Z.; Dumont, S.; Pecker, J.-C.; Chipman, E.; Artzner, G. E.; Vial, J. C.

    1982-01-01

    The OSO-8 satellite enabled the study of various characteristics of the profiles of Si II, Si IV, C IV, and O VI lines above active areas of the sun, as well as above quiet areas, and the derivation of some physical properties of the transition region between chromosphere and corona (CCT). The study of the lines shows a general tendency for the microvelocity fields on the average to be nearly constant for the heights corresponding to a temperature greater than 100,000 K; however they seem to slightly increase with height in quiet areas, and decrease in active areas. A multicomponent model of the CCT is necessary, and its geometry is far from being a set of plane-parallel columns. It is similar to an association of moving knots within the nonmoving principal component of the matter. The proportion of mass, in the knots relative to that in the nonmoving component, is several times larger in active regions than in quiet regions. In the knots, the nonthermal microvelocity fields are smaller in active regions and seem to decrease for temperature increasing above 100,000 K, contrary to what happens in the steady principal component.

  19. The evolution of a jet ejection of the ultraluminous X-ray source Holmberg II X-1

    CERN Document Server

    Cseh, D; Jonker, P G; Grise, F; Paragi, Z; Corbel, S; Falcke, H; Frey, S; Kaaret, P; Koerding, E

    2015-01-01

    We present quasi-simultaneous, multi-epoch radio and X-ray measurements of Holmberg II X-1 using the European VLBI Network (EVN), the Karl G. Jansky Very Large Array (VLA), and the Chandra and Swift X-ray telescopes. The X-ray data show apparently hard spectra with steady X-ray luminosities 4 months apart from each other. In the high-resolution EVN radio observations, we have detected an extended milli-arcsecond scale source with unboosted radio emission. The source emits non-thermal, likely optically thin synchrotron emission and its morphology is consistent with a jet ejection. The 9-GHz VLA data show an arcsecond-scale triple structure of Holmberg II X-1 similar to that seen at lower frequencies. However, we find that the central ejection has faded by at least a factor of 7.3 over 1.5 years. We estimate the dynamical age of the ejection to be higher than 2.1 years. We show that such a rapid cooling can be explained with simple adiabatic expansion losses. These properties of Holmberg II X-1 imply that ULX r...

  20. Ambient formaldehyde source attribution in Houston during TexAQS II and TRAMP

    Science.gov (United States)

    Buzcu Guven, Birnur; Olaguer, Eduardo P.

    2011-08-01

    An online data repository known as the Air Research Information Infrastructure (ARII) was used to discriminate large industrial sources of formaldehyde (HCHO) from mobile and secondary formaldehyde sources in Houston. Analysis of continuous online measurements at one urban and two industrial sites obtained during the summer of 2006 enabled us to isolate and evaluate major source factors associated with formaldehyde. The contribution of industrial sources to total atmospheric formaldehyde at the urban Houston site is estimated to be 17%, compared to 23% for mobile sources, 36% secondary formation, and 24% biogenic sources. The potential industrial sources include flares from petrochemical plants and refineries in the Port of Houston. The relative contribution of industrial source factors to ambient HCHO at the urban site increased to about 66% on some mornings, coinciding with the HCHO peak concentration. Secondary formation of HCHO during the day and night resulted from reactions of industrial olefins and other VOCs with OH or ozone. Some peak HCHO concentrations can also be linked to emission events of other VOCs, while a significant portion remains unexplained by the reported events. It is likely, based on the results from the SHARP campaign and our analysis, that some episodic emission events releasing primary HCHO are unreported to the Texas Commission on Environmental Quality (TCEQ).

  1. Analysis of petroleum company investments in nonpetroleum energy sources. Book II. Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, P. Jr.; Ryan, T.C.

    1979-12-12

    Financial data from the analysis of investment strategies of US oil companies and the depth of their present and future investments in nonpetroleum energy sources are tabulated in these appendices. The nonpetroleum energy sources included in the study are: coal, oil shale, geothermal, and solar.

  2. A New Hermean Magnetic Field Model using a Modified Equivalent Source Dipole Method

    Science.gov (United States)

    Oliveira, Joana S.; Langlais, Benoit; Pais, M. Alexandra; Amit, Hagay; Thébault, Erwan

    2017-04-01

    Mercury is the only terrestrial planet, besides the Earth, that has a core dynamo which generates a global magnetic field. MESSENGER orbited Mercury from 2011 to 2015 and provided magnetic measurements which convey crucial information on the magnetic field environment of the planet. We use a local method based on Equivalent Source Dipole approach to model the internal field of Mercury. The method is especially well suited when measurements cover a limited fraction of the planet's surface. Dipoles are placed deep into the planet. Note that with this modeling scheme, we do not attempt to explicitly model the external field. As the planet is in spin-orbit resonance completing three sidereal days in two years, it takes three sidereal days (one solar day) for the Sun to cover all local longitudes. We therefore consider successive periods of one solar day. A dominantly axisymmetric field is found for each solar-day model showing a significant temporal variability. This could be due to some large-scale external field that appears as internal with respect to the spacecraft orbit. The changing altitude and latitude coverage of each model may also be invoked for this variability. We finally compute a 8-solar-day model, including all solar days during the MESSENGER mission, to describe the Hermean magnetic field. Maps of the field computed at 200 km altitude show a magnetic equator at 16°N latitude, and confirm the large-scale and close-to-axisymmetry structure of the internal magnetic field of Mercury. Our model is also in agreement with the magnetic equator crossings detected before. However, our magnetic equator latitude varies with the altitude to the planet. This is indicative that the dipole-offset hypothesis is over-simplified, and that dynamo modelers have to consider alternative models when attempting to model the Hermean dynamo.

  3. Evaluation of thermal neutron irradiation field using a cyclotron-based neutron source for alpha autoradiography.

    Science.gov (United States)

    Tanaka, H; Sakurai, Y; Suzuki, M; Masunaga, S; Mitsumoto, T; Kinashi, Y; Kondo, N; Narabayashi, M; Nakagawa, Y; Watanabe, T; Fujimoto, N; Maruhashi, A; Ono, K

    2014-06-01

    It is important to measure the microdistribution of (10)B in a cell to predict the cell-killing effect of new boron compounds in the field of boron neutron capture therapy. Alpha autoradiography has generally been used to detect the microdistribution of (10)B in a cell. Although it has been performed using a reactor-based neutron source, the realization of an accelerator-based thermal neutron irradiation field is anticipated because of its easy installation at any location and stable operation. Therefore, we propose a method using a cyclotron-based epithermal neutron source in combination with a water phantom to produce a thermal neutron irradiation field for alpha autoradiography. This system can supply a uniform thermal neutron field with an intensity of 1.7×10(9) (cm(-2)s(-1)) and an area of 40mm in diameter. In this paper, we give an overview of our proposed system and describe a demonstration test using a mouse liver sample injected with 500mg/kg of boronophenyl-alanine.

  4. Cosmic-ray source of runaway electrons in thundercloud electric field.

    Science.gov (United States)

    Babich, L. P.; Bochkov, E. I.; Kutsyk, I. M.

    2008-12-01

    To increase an accuracy of numerical simulations of the high-altitude and high-energy electric phenomena in thunderstorm atmosphere basing on the electric breakdown combining the cosmic-ray effects and relativistic runaway electron (RE) avalanches it is necessary to have accurate source of seed REs produced by cosmic rays. We calculated the source using the Monte-Carlo technique. Actually a number of secondary electrons was calculated with energies above the runaway threshold depending on the field overvoltage relative to the minimum of the drag force affecting electrons. The cosmic radiation propagation through the atmosphere was simulated based on simplified model of the nuclear cascade: a cosmic proton was assumed to completely lose its energy in the first interaction with air nuclei, producing 15 pions with equal energies. The flux of primary radiation was divided into 20 angular groups containing equal number of particles. In view of the lack of the experimental data on the RE source it is impossible to directly estimate the accuracy of the obtained source. Therefore the model reliability was verified by comparing results of secondary radiation calculations with known experimental altitude variations in the secondary cosmic rays and their spectra. The source was calculated as the specific generation rate of the secondary electrons by cosmic radiation dependent on electric field overvoltage and the altitude above the Earth's surface. It is recommended as a source of relativistic runaway electron avalanches in numerical simulations of electric discharges in atmosphere controlled by REs in thunderstorm fields and their emissions: optical, gamma and neutrons. The source already was used to simulate the high-altitude discharge and its emissions. In particular, the calculated gamma-ray pulses (photon numbers and spectra, pulse duration) agree with detected terrestrial gamma-ray flashes (TGFs). Conclusions of the published analyses (Cummer and Lyons, 2005; Cummer et

  5. Module II development of Espadarte Field: from the conception to the first oil; Desenvolvimento do modulo II do Campo de Espadarte: da concepcao ao primeiro oleo

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Marcelo Oliveira de [Unidade de Negocios Bacia de Campos. Ativo de Producao Centro. Gerencia de Intervencoes em Pocos (Brazil)], e-mail: marcelo.andrade@petrobras.com.br

    2008-12-15

    The goal of the present article is to present the main challenges encountered in the construction of nine wells of module II of the Espadarte Field development project, a concession of the Center Production Asset of the Campos Basin Business Unit. Some innovations involved in the project will also be presented as well as some results concerning the time for the construction of the wells. (author)

  6. The neon gas field ion source-a first characterization of neon nanomachining properties

    Energy Technology Data Exchange (ETDEWEB)

    Livengood, Richard H., E-mail: richard.h.livengood@intel.com [Intel Corporation, Intel Architecture Group, Santa Clara, CA (United States); Tan, Shida; Hallstein, Roy [Intel Corporation, Intel Architecture Group, Santa Clara, CA (United States); Notte, John; McVey, Shawn; Faridur Rahman, F.H.M. [Carl Zeiss SMT, Nano Technology Systems Division, Peabody, MA (United States)

    2011-07-21

    At the Charged Particle Optics Conference (CPO7) in 2006, a novel trimer based helium gas field ion source (GFIS) was introduced for use in a new helium ion microscope (HIM), demonstrating the novel source performance attributes and unique imaging applications of the HIM (Hill et al., 2008 ; Livengood et al., 2008). Since that time there have been numerous enhancements to the HIM source and platform demonstrating resolution scaling into the sub 0.5 nm regime (Scipioni et al., 2009 ; Pickard et al., 2010). At this Charged Particle Optics Conference (CPO8) we will be introducing a neon version of the trimer-GFIS co-developed by Carl Zeiss SMT and Intel Corporation. The neon source was developed as a possible supplement to the gallium liquid metal ion source (LMIS) used today in most focused ion beam (FIB) systems (Abramo et al., 1994 ; Young et al.,1998). The neon GFIS source has low energy spread ({approx}1 eV) and a small virtual source size (sub-nanometer), similar to that of the helium GFIS. However neon does differ from the helium GFIS in two significant ways: neon ions have high sputtering yields (e.g. 1 Si atom per incident ion at 20 keV); and have relatively shallow implant depth (e.g. 46 nm in silicon at 20 keV). Both of these are limiting factors for helium in many nanomachining applications. In this paper we will present both simulation and experimental results of the neon GFIS used for imaging and nanomachining applications.

  7. Characteristics of a high brightness gaseous field ion source employing tungsten-carbon doped NiAl needles

    Energy Technology Data Exchange (ETDEWEB)

    Mousa, Marwan S., E-mail: mmousa@mutah.edu.jo [Department of Physics, Mu' tah University, P.O. Box 7, Al-Karak (Jordan)

    2011-05-15

    We report on the characterization of a high brightness gaseous field ion source using an emitter made of a NiAl needle containing tiny spherical tungsten-carbon precipitates. By field evaporation of such a multiphase alloy, a surface protrusion is formed out of a precipitate, which can act as a small source size field ion emitter. The emission current-voltage characteristics of this emitter were recorded for a variety of parameters. The results obtained suggest that its application as a stable ion source is possible even on long term operation. -- Research highlights: {yields} High brightness gaseous field ion source of precipitation hardened NiAl+W+C emitter. {yields} Emission current-voltage characteristics are recorded for a variety of parameters. {yields} Very small virtual source sizes and energy spreads can be attained. {yields} Results suggest that application as long term stable ion source is possible.

  8. Assessing the pollution risk of a groundwater source field at western Laizhou Bay under seawater intrusion.

    Science.gov (United States)

    Zeng, Xiankui; Wu, Jichun; Wang, Dong; Zhu, Xiaobin

    2016-07-01

    Coastal areas have great significance for human living, economy and society development in the world. With the rapid increase of pressures from human activities and climate change, the safety of groundwater resource is under the threat of seawater intrusion in coastal areas. The area of Laizhou Bay is one of the most serious seawater intruded areas in China, since seawater intrusion phenomenon was firstly recognized in the middle of 1970s. This study assessed the pollution risk of a groundwater source filed of western Laizhou Bay area by inferring the probability distribution of groundwater Cl(-) concentration. The numerical model of seawater intrusion process is built by using SEAWAT4. The parameter uncertainty of this model is evaluated by Markov Chain Monte Carlo (MCMC) simulation, and DREAM(ZS) is used as sampling algorithm. Then, the predictive distribution of Cl(-) concentration at groundwater source field is inferred by using the samples of model parameters obtained from MCMC. After that, the pollution risk of groundwater source filed is assessed by the predictive quantiles of Cl(-) concentration. The results of model calibration and verification demonstrate that the DREAM(ZS) based MCMC is efficient and reliable to estimate model parameters under current observation. Under the condition of 95% confidence level, the groundwater source point will not be polluted by seawater intrusion in future five years (2015-2019). In addition, the 2.5% and 97.5% predictive quantiles show that the Cl(-) concentration of groundwater source field always vary between 175mg/l and 200mg/l. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. 5 CFR Appendix II to Part 1201 - Appropriate Regional or Field Office for Filing Appeals

    Science.gov (United States)

    2010-01-01

    ... ORGANIZATION AND PROCEDURES PRACTICES AND PROCEDURES Pt. 1201, App. II Appendix II to Part 1201—Appropriate...-5109, (Arizona; Colorado; Kansas—except Kansas City; Montana; Nebraska; New Mexico; North Dakota; South...

  10. High-Redshift Superwinds as the Source of the Strongest Mg II Absorbers A Feasibility Analysis

    CERN Document Server

    Bond, N A; Charlton, J C; Vogt, S S

    2001-01-01

    We present HIRES/Keck profiles of four extremely strong (W_r > 1.8 A) Mg II absorbers at 1 1.8 A evolve away from z = 2 to the present. We propose that a substantial fraction of these very strong absorbers are due to superwinds and that their evolution is related to the redshift evolution of star-forming galaxies. Based on the observed redshift number density of W_r > 1.8 A Mg II absorbers at 1 < z < 2, we explore whether it is realistic that superwinds from starbursting galaxies could give rise to these absorbers. Finally, we do an analysis of the superwind connection to damped Lya absorbers (DLAs). DLAs and superwinds evolve differently and usually have different kinematic structure, indicating that superwinds probably do not give rise to the majority of DLAs.

  11. Fast-ignition design transport studies: realistic electron source, integrated PIC-hydrodynamics, imposed magnetic fields

    CERN Document Server

    Strozzi, D J; Larson, D J; Divol, L; Kemp, A J; Bellei, C; Marinak, M M; Key, M H

    2012-01-01

    Transport modeling of idealized, cone-guided fast ignition targets indicates the severe challenge posed by fast-electron source divergence. The hybrid particle-in-cell [PIC] code Zuma is run in tandem with the radiation-hydrodynamics code Hydra to model fast-electron propagation, fuel heating, and thermonuclear burn. The fast electron source is based on a 3D explicit-PIC laser-plasma simulation with the PSC code. This shows a quasi two-temperature energy spectrum, and a divergent angle spectrum (average velocity-space polar angle of 52 degrees). Transport simulations with the PIC-based divergence do not ignite for > 1 MJ of fast-electron energy, for a modest 70 micron standoff distance from fast-electron injection to the dense fuel. However, artificially collimating the source gives an ignition energy of 132 kJ. To mitigate the divergence, we consider imposed axial magnetic fields. Uniform fields ~50 MG are sufficient to recover the artificially collimated ignition energy. Experiments at the Omega laser facil...

  12. LOFAR 150-MHz observations of the Boötes field: catalogue and source counts

    Science.gov (United States)

    Williams, W. L.; van Weeren, R. J.; Röttgering, H. J. A.; Best, P.; Dijkema, T. J.; de Gasperin, F.; Hardcastle, M. J.; Heald, G.; Prandoni, I.; Sabater, J.; Shimwell, T. W.; Tasse, C.; van Bemmel, I. M.; Brüggen, M.; Brunetti, G.; Conway, J. E.; Enßlin, T.; Engels, D.; Falcke, H.; Ferrari, C.; Haverkorn, M.; Jackson, N.; Jarvis, M. J.; Kapińska, A. D.; Mahony, E. K.; Miley, G. K.; Morabito, L. K.; Morganti, R.; Orrú, E.; Retana-Montenegro, E.; Sridhar, S. S.; Toribio, M. C.; White, G. J.; Wise, M. W.; Zwart, J. T. L.

    2016-08-01

    We present the first wide area (19 deg2), deep (≈120-150 μJy beam-1), high-resolution (5.6 × 7.4 arcsec) LOFAR High Band Antenna image of the Boötes field made at 130-169 MHz. This image is at least an order of magnitude deeper and 3-5 times higher in angular resolution than previously achieved for this field at low frequencies. The observations and data reduction, which includes full direction-dependent calibration, are described here. We present a radio source catalogue containing 6 276 sources detected over an area of 19 deg2, with a peak flux density threshold of 5σ. As the first thorough test of the facet calibration strategy, introduced by van Weeren et al., we investigate the flux and positional accuracy of the catalogue. We present differential source counts that reach an order of magnitude deeper in flux density than previously achieved at these low frequencies, and show flattening at 150-MHz flux densities below 10 mJy associated with the rise of the low flux density star-forming galaxies and radio-quiet AGN.

  13. Synchrotron soft X-ray and field-emission electron sources: a comparison.

    Science.gov (United States)

    Spence, J C H; Howells, M R

    2002-12-01

    The soft X-ray spectral region and the useful range of electron energy-loss spectroscopy are very similar, both including the energy range 100-1000 eV. Moreover, well-developed monochromators and parallel detection devices with comparable resolution exist for both. Despite the differing interactions of electrons and photons, many complementary experiments in imaging, spectroscopy and diffraction have been performed using both techniques. We therefore compare the brightness, degeneracy, monochromaticity, beam size, source size, spatial and temporal coherence of field-emission electron beams and soft X-ray synchrotron radiation from typical undulators. Recent brightness values for nanotip field emitters and undulators, both measured and calculated, are provided with examples from the Advanced Light Source synchrotron-radiation facility at Berkeley USA. The quantum mechanical upper limit on source brightness, as well as relationships among beam brightness, coherence parameters, and degeneracy, are discussed. Factors which limit these parameters and methods of measurement are reviewed, and the implications for diffraction, imaging and spectroscopic experiments as well as radiation damage are briefly commented on.

  14. Infrared-Faint Radio Sources in the SERVS deep fields: Pinpointing AGNs at high redshift

    CERN Document Server

    Maini, Alessandro; Norris, Ray P; Spitler, Lee R; Mignano, Arturo; Lacy, Mark; Morganti, Raffaella

    2016-01-01

    Infrared-Faint Radio Sources (IFRS) represent an unexpected class of objects relatively bright at radio wavelength, but unusually faint at infrared (IR) and optical wavelengths. A recent and extensive campaign on the radio-brightest IFRSs (S_{1.4GHz} >= 10 mJy) has provided evidence that most of them (if not all) contain an AGN. Still uncertain is the nature of the radio-faintest ones (S_{1.4GHz} 4). We analysed a number of IFRS samples identified in SERVS fields, including a new sample (21 sources) extracted from the Lockman Hole. 3.6 and 4.5 mum IR counterparts of the 64 sources located in the SERVS fields were searched for, and, when detected, their IR properties were studied. We compared the radio/IR properties of the IR-detected IFRSs with those expected for a number of known classes of objects. We found that they are mostly consistent with a mixture of high-redshift (z >= 3) radio-loud AGNs. The faintest ones (S_{1.4GHz} ~ 100 muJy), however, could be also associated with nearer (z ~ 2) dust-enshrouded...

  15. LOFAR 150-MHz observations of the Bo\\"otes field: Catalogue and Source Counts

    CERN Document Server

    Williams, W L; Röttgering, H J A; Best, P; Dijkema, T J; de Gasperin, F; Hardcastle, M J; Heald, G; Prandoni, I; Sabater, J; Shimwell, T W; Tasse, C; van Bemmel, I M; Brüggen, M; Brunetti, G; Conway, J E; Enßlin, T; Engels, D; Falcke, H; Ferrari, C; Haverkorn, M; Jackson, N; Jarvis, M J; Kapinska, A D; Mahony, E K; Miley, G K; Morabito, L K; Morganti, R; Orrú, E; Retana-Montenegro, E; Sridhar, S S; Toribio, M C; White, G J; Wise, M W; Zwart, J T L

    2016-01-01

    We present the first wide area (19 deg$^2$), deep ($\\approx120-150$ {\\mu}Jy beam$^{-1}$), high resolution ($5.6 \\times 7.4$ arcsec) LOFAR High Band Antenna image of the Bo\\"otes field made at 130-169 MHz. This image is at least an order of magnitude deeper and 3-5 times higher in angular resolution than previously achieved for this field at low frequencies. The observations and data reduction, which includes full direction-dependent calibration, are described here. We present a radio source catalogue containing 6276 sources detected over an area of $19$\\,deg$^2$, with a peak flux density threshold of $5\\sigma$. As the first thorough test of the facet calibration strategy, introduced by van Weeren et al., we investigate the flux and positional accuracy of the catalogue. We present differential source counts that reach an order of magnitude deeper in flux density than previously achieved at these low frequencies, and show flattening at 150 MHz flux densities below 10 mJy associated with the rise of the low flux...

  16. Near-field hazard assessment of March 11, 2011 Japan Tsunami sources inferred from different methods

    Science.gov (United States)

    Wei, Y.; Titov, V.V.; Newman, A.; Hayes, G.; Tang, L.; Chamberlin, C.

    2011-01-01

    Tsunami source is the origin of the subsequent transoceanic water waves, and thus the most critical component in modern tsunami forecast methodology. Although impractical to be quantified directly, a tsunami source can be estimated by different methods based on a variety of measurements provided by deep-ocean tsunameters, seismometers, GPS, and other advanced instruments, some in real time, some in post real-time. Here we assess these different sources of the devastating March 11, 2011 Japan tsunami by model-data comparison for generation, propagation and inundation in the near field of Japan. This study provides a comparative study to further understand the advantages and shortcomings of different methods that may be potentially used in real-time warning and forecast of tsunami hazards, especially in the near field. The model study also highlights the critical role of deep-ocean tsunami measurements for high-quality tsunami forecast, and its combination with land GPS measurements may lead to better understanding of both the earthquake mechanisms and tsunami generation process. ?? 2011 MTS.

  17. Novel thin film field emission electron source laboratory directed research and development final report

    Energy Technology Data Exchange (ETDEWEB)

    Walko, R.J.; Fleming, J.G.; Hubbs, J.W.

    1997-04-01

    The objective of this project was to demonstrate proof of concept of a thin film field emission electron source based on electron tunneling between discrete metal islands on an insulating substrate. An electron source of this type should be more easily fabricated permitting the use of a wider range of materials, and be less prone to damage and erratic behavior than the patterned field emitter arrays currently under development for flat panel displays and other vacuum microelectronic applications. This report describes the results of the studies of electron and light emission from such structures, and the subsequent discovery of a source of light emission from conductive paths across thin insulating gaps of the semiconductor-insulator-semiconductor (SIS) and metal-insulator-semiconductor (MIS) structures. The substrates consisted of silicon nitride and silicon dioxide on silicon wafers, Kapton{reg_sign}, quartz, and cut slabs of silica aerogels. The conductive film samples were prepared by chemical vapor deposition (CVD) and sputtering, while the MIS and SIS samples were prepared by CVD followed by cleaving, grinding, mechanical indentation, erosion by a sputter Auger beam, electrical arcing and chemical etching. Electron emission measurements were conducted in high and ultra high vacuum systems at SNL, NM as well as at SNL, CA. Optical emission measurements were made in air under an optical microscope as well as in the above vacuum environments. Sample morphology was investigated using both scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

  18. Discrete and continuum simulations of near-field ground motion from Source Physics Experiments (SPE) (Invited)

    Science.gov (United States)

    Ezzedine, S. M.; Vorobiev, O.; Herbold, E. B.; Glenn, L. A.; Antoun, T.

    2013-12-01

    This work is focused on analysis of near-field measurements (up to 100 m from the source) recorded during Source Physics Experiments in a granitic formation. One of the main goals of these experiments is to investigate the possible mechanisms of shear wave generation in the nonlinear source region. SPE experiments revealed significant tangential motion (up to 30 % of the magnitude in the radial direction) at many locations. Furthermore, azimuthal variations in radial velocities were also observed which cannot be generated by a spherical source in isotropic materials. Understanding the nature of this non-radial motion is important for discriminating between the natural seismicity and underground explosions signatures. Possible mechanisms leading to such motion include, but not limited to, heterogeneities in the rock such as joints, faults and geologic layers as well as surface topography and vertical motion at the surface caused by material spall and gravity. We have performed a three dimensional computational studies considering all these effects. Both discrete and continuum methods have been employed to model heterogeneities. In the discrete method, the joints and faults were represented by cohesive contact elements. This enables us to examine various friction laws at the joints which include softening, dilatancy, water saturation and rate-dependent friction. Yet this approach requires the mesh to be aligned with joints, which may present technical difficulties in three dimensions when multiple non-persistent joints are present. In addition, the discrete method is more computationally expensive. The continuum approach assumes that the joints are stiff and the dilatancy and shear softening can be neglected. In this approach, the joints are modeled as weakness planes within the material, which are imbedded into and pass through many finite elements. The advantage of this approach is that it requires neither sophisticated meshing algorithms nor contact detection

  19. Optical design and performance of the phase II inelastic scattering beamline at the National Synchrotron Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Caliebe, W.A.; Kao, C.-C.; Oversluizen, T.; Montanez, P.; Hastings, J.B. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton New York, 11973 (United States); Caliebe, W.A. [Hamburger Synchrotronstrahlungslabor HASYLAB, Deutsches Elektronen-Synchrotron DESY, 22603Hamburg (Germany)] Krisch, M. [European Synchrotron Radiation Facility, F-38043Grenoble Cedex (France)

    1997-07-01

    We report the optical design and performance of the phase II inelastic scattering beamline at the National Synchrotron Light Source. The new beamline consists of a four-crystal Si(220) monochromator followed by a bent cylinder mirror. The monochromator is tunable from 5 to 10 keV with about 0.2 eV energy resolution throughout the tuning range. The size of the focused beam is about 0.5mm(H){times}0.3mm(V). {copyright} {ital 1997 American Institute of Physics.}

  20. The Neutron Energy Spectrum Study from the Phase II Solid Methane Moderator at the LENS Neutron Source

    OpenAIRE

    Shin, Yunchang; Snow, W. Mike; Lavelle, Christopher M.; Baxter, David V.; Tong, Xin; Yan, Haiyang; Leuschner, Mark

    2007-01-01

    Neutron energy spectrum measurements from a solid methane moderator were performed at the Low Energy Neutron Source (LENS) at Indiana University Cyclotron Facility (IUCF) to verify our neutron scattering model of solid methane. The time-of-flight method was used to measure the energy spectrum of the moderator in the energy range of 0.1$meV\\sim$ 1$eV$. Neutrons were counted with a high efficiency $^{3}{He}$ detector. The solid methane moderator was operated in phase II temperature and the ener...

  1. High Field Pulsed Magnets for Neutron Scattering at the Spallation Neutron Source

    Science.gov (United States)

    Granroth, G. E.; Lee, J.; Fogh, E.; Christensen, N. B.; Toft-Petersen, R.; Nojiri, H.

    2015-03-01

    A High Field Pulsed Magnet (HFPM) setup, is in use at the Spallation Nuetron Source(SNS), Oak Ridge National Laboratory. With this device, we recently measured the high field magnetic spin structure of LiNiPO4. The results of this study will be highlighted as an example of possible measurements that can be performed with this device. To further extend the HFPM capabilities at SNS, we have learned to design and wind these coils in house. This contribution will summarize the magnet coil design optimization procedure. Specifically by varying the geometry of the multi-layer coil, we arrive at a design that balances the maximum field strength, neutron scattering angle, and the field homogeneity for a specific set of parameters. We will show that a 6.3kJ capacitor bank, can provide a magnetic field as high as 30T for a maximum scattering angle around 40° with homogeneity of +/- 4 % in a 2mm diameter spherical volume. We will also compare the calculations to measurements from a recently wound test coil. This work was supported in part by the Lab Directors' Research and Development Fund of ORNL.

  2. Effect of an electric field on superfluid helium scintillation produced by α-particle sources

    Science.gov (United States)

    Ito, T. M.; Clayton, S. M.; Ramsey, J.; Karcz, M.; Liu, C.-Y.; Long, J. C.; Reddy, T. G.; Seidel, G. M.

    2012-04-01

    We report a study of the intensity and time dependence of scintillation produced by weak α-particle sources in superfluid helium in the presence of an electric field (0-45 kV/cm) in the temperature range of 0.2 to 1.1 K at the saturated vapor pressure. Both the prompt and the delayed components of the scintillation exhibit a reduction in intensity with the application of an electric field. The reduction in the intensity of the prompt component is well approximated by a linear dependence on the electric field strength with a reduction of 15% at 45 kV/cm. When analyzed using the Kramers theory of columnar recombination, this electric field dependence leads to the conclusion that roughly 40% of the scintillation results from species formed from atoms originally promoted to excited states and 60% from excimers created by ionization and subsequent recombination with the charges initially having a cylindrical Gaussian distribution about the α track of 60 nm radius. The intensity of the delayed component of the scintillation has a stronger dependence on the electric field strength and on temperature. The implications of these data on the mechanisms affecting scintillation in liquid helium are discussed.

  3. Source imaging of potential fields through a matrix space-domain algorithm

    Science.gov (United States)

    Baniamerian, Jamaledin; Oskooi, Behrooz; Fedi, Maurizio

    2017-01-01

    Imaging of potential fields yields a fast 3D representation of the source distribution of potential fields. Imaging methods are all based on multiscale methods allowing the source parameters of potential fields to be estimated from a simultaneous analysis of the field at various scales or, in other words, at many altitudes. Accuracy in performing upward continuation and differentiation of the field has therefore a key role for this class of methods. We here describe an accurate method for performing upward continuation and vertical differentiation in the space-domain. We perform a direct discretization of the integral equations for upward continuation and Hilbert transform; from these equations we then define matrix operators performing the transformation, which are symmetric (upward continuation) or anti-symmetric (differentiation), respectively. Thanks to these properties, just the first row of the matrices needs to be computed, so to decrease dramatically the computation cost. Our approach allows a simple procedure, with the advantage of not involving large data extension or tapering, as due instead in case of Fourier domain computation. It also allows level-to-drape upward continuation and a stable differentiation at high frequencies; finally, upward continuation and differentiation kernels may be merged into a single kernel. The accuracy of our approach is shown to be important for multi-scale algorithms, such as the continuous wavelet transform or the DEXP (depth from extreme point method), because border errors, which tend to propagate largely at the largest scales, are radically reduced. The application of our algorithm to synthetic and real-case gravity and magnetic data sets confirms the accuracy of our space domain strategy over FFT algorithms and standard convolution procedures.

  4. Strains of scattering of near-field of a point source

    Indian Academy of Sciences (India)

    M D Sharma

    2004-06-01

    Three dimensional scattering of near-field is studied for dilatation and rotation in the time domain. The perturbation method is applied to solve the equation of motion for the first order scattering from a weak inhomogeneity in an otherwise homogeneous medium. The inhomogeneity is assumed close enough to the point source so that the near-field intermediate wave is dominating over the far-field spherical and pulses. The integral expressions are derived to relate dilatation and rotation of scattering to the radial fluctuations of velocities and density in the inhomogeneity. These integrals are solved to calculate the strains of scattering from (a part of) an inhomogeneous spherical shell of arbitrary curvature. Variable curvature may allow the shape of inhomogeneity volume element to change uniformly from spherical to rectangular. Rotation of scattering from a spherical shell is independent of wave velocity inhomogeneity. Dilatation of scattering does not involve wave velocity inhomogeneity but its gradient. The back scattering results are obtained as a special case. Strains are computed numerically, for hypothetical models to study the effects of various parameters viz., velocity inhomogeneity, distance of source from inhomogeneity and from receiver, and thickness of inhomogeneity. The curvature of the spherical shell is varied to study the effects of the shape of inhomogeneous volume element on scattering.

  5. CHANDRA OBSERVATIONS OF 3C RADIO SOURCES WITH z < 0.3. II. COMPLETING THE SNAPSHOT SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F. [SLAC National Laboratory and Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Tremblay, G. R. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Muenchen (Germany); Harris, D. E.; O' Dea, C. P. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Kharb, P.; Axon, D. [Department of Physics, Rochester Institute of Technology, Carlson Center for Imaging Science 76-3144, 84 Lomb Memorial Dr., Rochester, NY 14623 (United States); Balmaverde, B.; Capetti, A. [INAF-Osservatorio Astrofisico di Torino, Strada Osservatorio 20, I-10025 Pino Torinese (Italy); Baum, S. A. [Carlson Center for Imaging Science 76-3144, 84 Lomb Memorial Dr., Rochester, NY 14623 (United States); Chiaberge, M.; Macchetto, F. D.; Sparks, W. [Space Telescope Science Institute, 3700 San Martine Drive, Baltimore, MD 21218 (United States); Gilli, R. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Giovannini, G. [INAF-Istituto di Radioastronomia di Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Grandi, P.; Torresi, E. [INAF-IASF-Istituto di Astrofisica Spaziale e fisica Cosmica di Bologna, Via P. Gobetti 101, I-40129 Bologna (Italy); Risaliti, G. [INAF-Osservatorio Astronomico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy)

    2012-12-15

    We report on the second round of Chandra observations of the 3C snapshot survey developed to observe the complete sample of 3C radio sources with z < 0.3 for 8 ks each. In the first paper, we illustrated the basic data reduction and analysis procedures performed for the 30 sources of the 3C sample observed during Chandra Cycle 9, while here we present the data for the remaining 27 sources observed during Cycle 12. We measured the X-ray intensity of the nuclei and of any radio hot spots and jet features with associated X-ray emission. X-ray fluxes in three energy bands, i.e., soft, medium, and hard, for all the sources analyzed are also reported. For the stronger nuclei, we also applied the standard spectral analysis, which provides the best-fit values of the X-ray spectral index and absorbing column density. In addition, a detailed analysis of bright X-ray nuclei that could be affected by pile-up has been performed. X-ray emission was detected for all the nuclei of the radio sources in our sample except for 3C 319. Among the current sample, there are two compact steep spectrum radio sources, two broad-line radio galaxies, and one wide angle tail radio galaxy, 3C 89, hosted in a cluster of galaxies clearly visible in our Chandra snapshot observation. In addition, we also detected soft X-ray emission arising from the galaxy cluster surrounding 3C 196.1. Finally, X-ray emission from hot spots has been found in three FR II radio sources and, in the case of 3C 459, we also report the detection of X-ray emission associated with the eastern radio lobe as well as X-ray emission cospatial with radio jets in 3C 29 and 3C 402.

  6. The faint radio source population at 15.7 GHz - II. Multi-wavelength properties

    CERN Document Server

    Whittam, I H; Green, D A; Jarvis, M J; Vaccari, M

    2015-01-01

    A complete, flux density limited sample of 96 faint ($> 0.5$ mJy) radio sources is selected from the 10C survey at 15.7 GHz in the Lockman Hole. We have matched this sample to a range of multi-wavelength catalogues, including SERVS, SWIRE, UKIDSS and optical data; multi-wavelength counterparts are found for 80 of the 96 sources and spectroscopic redshifts are available for 24 sources. Photometric reshifts are estimated for the sources with multi-wavelength data available; the median redshift of the sample is 0.91 with an interquartile range of 0.84. Radio-to-optical ratios show that at least 94 per cent of the sample are radio loud, indicating that the 10C sample is dominated by radio galaxies. This is in contrast to samples selected at lower frequencies, where radio-quiet AGN and starforming galaxies are present in significant numbers at these flux density levels. All six radio-quiet sources have rising radio spectra, suggesting that they are dominated by AGN emission. These results confirm the conclusions o...

  7. Source mechanism of small-moderate earthquakes and tectonic stress field in Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    吴建平; 明跃红; 王椿镛

    2004-01-01

    In the paper, source mechanisms of 33 small-moderate earthquakes occurred in Yunnan are determined by modeling of regional waveforms from Yunnan digital seismic network. The result shows that most earthquakes occurred within or near the Chuandian rhombic block have strike-slip mechanism. The orientations of maximum compressive stresses obtained from source mechanism are changed from NNW-SSN to NS in the areas from north to south of the block, and tensile stresses are mainly in ENE-WSW or NE-SE. In the eastern Tibetan Plateau, the orientations of maximum compressive stress radiate toward outside from the plateau, and the tensile stress orientations mostly parallel to arc structures. Near 28°N the orientations of both maximum compressive stress and tensile stress changed greatly, and the boundary seems to correspond to the southwestern extended line of Longmenshan fault. Outside of the Chuandian rhombic block, the orientations of P and T axes are some different from those within the block. The comparison shows that the source mechanism of small-moderate events presented in the paper is consistence with that of moderate-strong earthquakes determined by Harvard University, which means the source mechanism of small-moderate events can be used to study the tectonic stress field in this region.

  8. Linear Track Estimation Using Double Pulse Sources for Near-Field Underwater Moving Target

    Institute of Scientific and Technical Information of China (English)

    Zhifei Chen; Hong Hou; Jianhua Yang; Jincai Sun; Qian Wang

    2013-01-01

    The double pulse sources (DPS) method is presented for linear track estimation in this work.In the field of noise identification of underwater moving target,the Doppler will distort the frequency and amplitude of the radiated noise.To eliminate this,the track estimation is necessary.In the DPS method,we first estimate bearings of two sinusoidal pulse sources installed in the moving target through baseline positioning method.Meanwhile,the emitted and recorded time of each pulse are also acquired.Then the linear track parameters will be achieved based on the geometry pattern with the help of double sources spacing.The simulated results confirm that the DPS improves the performance of the previous double source spacing method.The simulated experiments were carried out using a moving battery car to further evaluate its performance.When the target is 40-60m away,the experiment results show that biases of track azimuth and abeam distance of DPS are under 0.6° and 3.4m,respectively.And the average deviation of estimated velocity is around 0.25m/s.

  9. Stellar Sources in the ISOGAL Inner Galactic Bulge Field (=00, =-10)

    Indian Academy of Sciences (India)

    D. Κ. Ojha; A. Omont; S. Ganesh; G. Simon; Μ. Schultheis

    2000-06-01

    ISOGAL is a survey at 7 and 15 μm with ISOCAM of the inner galactic disk and bulge of our Galaxy. The survey covers ∼ 22 deg2 in selected areas of the central = ± 30 degree of the inner Galaxy. In this paper, we report the study of a small ISOGAL field in the inner galactic bulge (=0°, =-1°, area = 0.033deg2). Using the multicolor near-infrared data (IJK) of DENIS (DEep Near Infrared Southern Sky Survey) and mid-infrared ISOGAL data, we discuss the nature of the ISOGAL sources. The various color-color and color-magnitude diagrams are discussed in the paper. While most of the detected sources are red giants (RGB tip stars), a few of them show an excess in J-K and K-[15] colors with respect to the red giant sequence. Most of them are probably AGB stars with large mass-loss rates.

  10. Piranti Lunak Pengujian Struktur Matematika Grup, Ring, Field Berbasis Osp (Open Source Program

    Directory of Open Access Journals (Sweden)

    Ngarap Im Manik

    2014-06-01

    Full Text Available This design of a computer software is a development and continuation of the software made on the previous research (2009/2010. However, this further research developed and expanded the scopes of testing more on the Siclic Group, Isomorphism Group, Semi Group, Sub Group and Abelian Group, Factor Ring, Sub Ring and Polynomial Ring; developed on the OSP (Open Source Program-based. The software was developed using the OSP-based language programming, such Java, so it is open and free to use for its users. This research succeeded to develop an open source software of Java program that can be used for testing specific mathematical Groups, such Ciclic Group, Isomorphism Group, Semi Group, Sub Group and Abelian Group, and Rings, Commutative Ring, Division Ring, Ideal Sub Ring, Ring Homomorphism, Ring Epimorphism and Fields. By the results, the software developed was able to test as same as the results from manual testing.

  11. Investigation of source-emission PM-10 particulate matter field studies of candidate methods. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Farthing, W.E.; Williamson, A.D.; Dawes, S.S.; Martin, R.S.; Ragland, J.W.

    1986-12-01

    The report outlines the results of four field tests of two candidate methods for source PM10 measurement. The first method involves a new sampling-train design which incorporates emission gas recycle (EGR) to avoid the anisokinetic sampling bias inherent in size-specific emissions measurement. The second technique, the simulated Method 5 (SIM-5) approach, uses existing sampling hardware with an altered traversing protocol to minimize this bias. The results of the test series suggest that both techniques are sufficiently advanced that they should be documented in more detail for potential use as sampling methods. Further, more extensive testing should be performed in order to define precision, reproducibility, and comparability of each technique as well as identify potential sources of interference or bias.

  12. Low-noise pulsed current source for magnetic-field measurements of magnets for accelerators

    Science.gov (United States)

    Omelyanenko, M. M.; Borisov, V. V.; Donyagin, A. M.; Khodzhibagiyan, H. G.; Kostromin, S. A.; Makarov, A. A.; Shemchuk, A. V.

    2017-01-01

    The schematic diagram, design, and technical characteristics of the pulsed current source developed and produced for the magnetic-field measurement system of superconducting magnets for accelerators are described. The current source is based on the current regulator with pass transistor bank in the linear mode. Output current pulses (0-100 A) are produced by utilizing the energy of the preliminarily charged capacitor bank (5-40 V), which is additionally charged between pulses. The output current does not have the mains frequency and harmonics ripple. The relative noise level is less than-100 dB (or 10-5) of RMS value (it is defined as the ratio of output RMS noise current to a maximal output current of 100 A within the operating bandwidth, expressed in dB). The work was performed at the Veksler and Baldin Laboratory of High Energy Physics, Joint Institute for Nuclear Research (JINR).

  13. Measurement of the Internal Magnetic Field of Plasmas using an Alpha Particle Source

    Energy Technology Data Exchange (ETDEWEB)

    S.J. Zweben; D.S. Darrow; P.W. Ross; J.L. Lowrance; G. Renda

    2004-05-13

    The internal magnetic fields of plasmas can be measured under certain conditions from the integrated v x B deflection of MeV alpha particles emitted by a small radioactive source. This alpha source and large-area alpha particle detector would be located inside the vacuum vessel but outside the plasma. Alphas with a typical energy of 5.5 MeV (241Am) can reach the center of almost all laboratory plasmas and magnetic fusion devices, so this method can potentially determine the q(r) profile of tokamaks or STs. Orbit calculations, background evaluations, and conceptual designs for such a vxB (or ''AVB'') detector are described.

  14. A designer ligand field for blue-green luminescence of organoeuropium(ii) sandwich complexes with cyclononatetraenyl ligands.

    Science.gov (United States)

    Kawasaki, Kenshiro; Sugiyama, Rion; Tsuji, Takashi; Iwasa, Takeshi; Tsunoyama, Hironori; Mizuhata, Yoshiyuki; Tokitoh, Norihiro; Nakajima, Atsushi

    2017-06-21

    A novel η(9)-coordinated double-decker sandwich complex of divalent europium is synthesized. The complex exhibits blue-green photoluminescence at 516 nm, which is significantly blue-shifted from those of other organoeuropium(ii) sandwich complexes (∼630 nm). The blue-shift was quantitatively explained by the weakened electrostatic field of the expanded 10-π ring.

  15. Hanna, Wyoming underground coal gasification data base. Volume 3. The Hanna II, Phase I field test

    Energy Technology Data Exchange (ETDEWEB)

    Bartke, T.C.; Fischer, D.D.; King, S.B.; Boyd, R.M.; Humphrey, A.E.

    1985-08-01

    This report is part of a seven-volume series on the Hanna, Wyoming, underground coal gasification field tests. Volume 1 is a summary of the project, and each of Volumes 2 through 6 describes a particular test. Volume 7 is a compilation of all the data for the tests in Volumes 2 through 6. Hanna II, Phase I was conducted during the spring and summer of 1975, at a site about 700 feet up dip (to the southwest) of the Hanna I test. The test was conducted in two stages - Phase IA and IB. Phase IA consisted of linking and gasification operations between Wells 1 and 3 and Phase IB of linking from the 1-3 gasification zone to Well 2, followed by a short period of gasification from Well 2 to Well 3 over a broad range of air injection rates, in order to determine system turndown capabilities and response times. This report covers: (1) site selection and characteristics; (2) test objectives; (3) facilities description; (4) pre-operational testing; (5) test operations summary; and (6) post-test activity. 7 refs., 11 figs., 8 tabs.

  16. Graphene field-effect transistors with tunable sensitivity for high performance Hg (II) sensing

    Science.gov (United States)

    Li, Peng; Liu, Baijun; Zhang, Dongzhi; Sun, Yan'e.; Liu, Jingjing

    2016-10-01

    Graphene field-effect transistors (FETs) capped with ionophore were fabricated to demonstrate the highly sensitive and selective detection of Hg (II) ions in solution. We systematically investigated the ion detection performances and sensing mechanism of this 2D material. Due to its ambipolar nature, graphene can work as either an n-type or a p-type sensor when a gate voltage is applied to switch its carrier characteristic, resulting in completely different sensing performances. The strong dependence of sensitivity on gate voltage was also investigated. Graphene FETs in optimal regimes were able to detect Hg2+ down to 0.1 ppb, one-fold lower than the World Health Organization tolerance level. Hg2+ ions can be effectively detected over a wide range of concentration (from 0.1 ppb to 1000 ppb) with graphene conductance change following the Langmuir isotherm for molecules adsorption on surface, and the time constant for ion adsorption extracted was only 3.5 s, approximately. The transfer characteristics of graphene FETs capped with mercury ionophore did not show obvious change by the existence of arsenite ions, demonstrating good selectivity. Our results illustrate the potential utility of ionophore integrated graphene FETs for monitoring heavy metal ions in solution.

  17. CALIFA, the Calar Alto Legacy Integral Field Area survey: II. First public data release

    CERN Document Server

    Husemann, B; Sánchez, S F; Barrado-Navascues, D; Bekeraitė, S; Bomans, D J; Castillo-Morales, A; Catalán-Torrecilla, C; Fernandes, R Cid; Falcón-Barroso, J; García-Benito, R; Delgado, R M González; Iglesias-Páramo, J; Johnson, B D; Kupko, D; López-Fernandez, R; Lyubenova, M; Marino, R A; Mast, D; Miskolczi, A; Monreal-Ibero, A; de Paz, A Gil; Pérez, E; Pérez, I; Rosales-Ortega, F F; Ruiz-Lara, T; Schilling, U; van de Ven, G; Walcher, J; Alves, J; de Amorim, A L; Backsmann, N; Barrera-Ballesteros, J K; Bland-Hawthorn, J; Dettmar, R -J; Demleitner, M; Díaz, A I; Enke, H; Florido, E; Flores, H; Galbany, L; Gallazzi, A; García-Lorenzo, B; Gomes, J M; Gruel, N; Haines, T; Holmes, L; Jungwiert, B; Kalinova, V; Kehrig, C; Kennicutt, R C; Klar, J; Lehnert, M D; Lóez-Sáchez, Á R; de Lorenzo-Cáceres, A; Mármol-Queraltó, E; Márquez, I; Mendez-Abreu, J; Mollá, M; del Olmo, A; Meidt, S E; Papaderos, P; Puschnig, J; Quirrenbach, A; Roth, M M; Sánchez-Blázquez, P; Spekkens, K; Singh, R; Stanishev, V; Trager, S C; Vilchez, J M; Wild, V; Wisotzki, L; Zibetti, S; Ziegler, B

    2012-01-01

    We present the first public data release of the CALIFA survey. It consists of science-grade optical datacubes for the first 100 of eventually 600 nearby (0.005field spectrograph PMAS/PPak mounted on the 3.5m telescope at the Calar Alto observatory. The galaxies in DR1 already cover a wide range of properties in color-magnitude space, morphological type, stellar mass, and gas ionization conditions. This offers the potential to tackle a variety of open questions in galaxy evolution using spatially resolved spectroscopy. Two different spectral setups are available for each galaxy, (i) a low-resolution V500 setup covering the nominal wavelength range 3745-7500A with a spectral resolution of 6.0A (FWHM), and (ii) a medium-resolution V1200 setup covering the nominal wavelength range 3650-4840A with a spectral resolution of 2.3A (FWHM). We present the characteristics and data structure of the CALIFA datasets that should be taken into account for scientific exploita...

  18. ALMA Deep Field in SSA22: Source Catalog and Number Counts

    Science.gov (United States)

    Umehata, Hideki; Tamura, Yoichi; Kohno, Kotaro; Ivison, R. J.; Smail, Ian; Hatsukade, Bunyo; Nakanishi, Kouichiro; Kato, Yuta; Ikarashi, Soh; Matsuda, Yuichi; Fujimoto, Seiji; Iono, Daisuke; Lee, Minju; Steidel, Charles C.; Saito, Tomoki; Alexander, D. M.; Yun, Min S.; Kubo, Mariko

    2017-01-01

    We present results from a deep 2‧ × 3‧ (comoving scale of 3.7 Mpc × 5.5 Mpc at z = 3) survey at 1.1 mm, taken with the Atacama Large Millimeter/submillimeter Array (ALMA) in the SSA22 field. We observe the core region of a z = 3.09 protocluster, achieving a typical rms sensitivity of 60 μJy beam‑1 at a spatial resolution of 0.″7. We detect 18 robust ALMA sources at a signal-to-noise ratio (S/N) > 5. Comparison between the ALMA map and a 1.1 mm map, taken with the AzTEC camera on the Atacama Submillimeter Telescope Experiment (ASTE), indicates that three submillimeter sources discovered by the AzTEC/ASTE survey are resolved into eight individual submillimeter galaxies (SMGs) by ALMA. At least 10 of our 18 ALMA SMGs have spectroscopic redshifts of z ≃ 3.09, placing them in the protocluster. This shows that a number of dusty starburst galaxies are forming simultaneously in the core of the protocluster. The nine brightest ALMA SMGs with S/N > 10 have a median intrinsic angular size of 0\\buildrel{\\prime\\prime}\\over{.} {32}-0.06+0.13 ({2.4}-0.4+1.0 physical kpc at z = 3.09), which is consistent with previous size measurements of SMGs in other fields. As expected, the source counts show a possible excess compared to the counts in the general fields at S1.1mm ≥ 1.0 mJy, due to the protocluster. Our contiguous mm mapping highlights the importance of large-scale structures on the formation of dusty starburst galaxies.

  19. Protracted Overexposure to a {sup 137}Cs Source: II, Clinical Sequelae

    Energy Technology Data Exchange (ETDEWEB)

    Baranov, A.E.; Guskova, A.K.; Davtian, A.A.; Sevankaev, A.V.; Lloyd, D.C.; Edwards, A.A.; Domracheva, E.V.; Gordeeva, A.A.; Gusev, I.A.; Mikhailova, G.F.; Moiseenko, V.V.; Nugis, V.Yu.; Olshanskaya, Yu.V

    1999-07-01

    The clinical condition and treatment of a driver who was overexposed to an unshielded {sup 137}Cs source that was in his truck for about 5 months is described. Bone marrow and blood changes are presented as he progressed from pancytopaenia to myelodysplasia with features of refractory anaemia and then anaemia with an excess of blasts and transformation to frank myelomonocytic leukaemia. He died about 22 months after the discovery of the source from an overwhelming hepatitis B infection concurrent with immunosuppression following cytostatic treatment for the leukaemia. (author)

  20. Permanent tremor of Masaya Volcano, Nicaragua: Wave field analysis and source location

    Science.gov (United States)

    MéTaxian, Jean-Philippe; Lesage, Philippe; Dorel, Jacques

    1997-10-01

    The Masaya Volcano, Nicaragua, is a basaltic caldera in a subduction zone. The permanent source of the volcanic tremor was located inside Santiago crater, at the lava lake's position and 400 m below the NE rim, and therefore corresponds to superficial magma activity. We used two tripartite arrays (90 m side), one semicircular array (r=120 m) in 1992, and two semicircular arrays (r=60 m) and a 2500 m long linear array radiating out from the source and on the flank of the crater in 1993. We used both a cross-spectrum method and a correlation method to determine the wave delay time between the reference station and the other stations of an array and to quantify the wave field. Using the delays therefore by intersecting the back azimuth wave directions from the arrays, we could pinpoint the source. Additionally, the correlation coefficients obtained as functions of frequency for the three components of motion confirm the inferred position of the source of tremor. The tremor's wave field is composed of comparable quantities of dispersed Rayleigh and Love surface waves, whose phase velocities lie in the ranges 730-1240 m/s at 2 Hz and 330-550 m/s at 6 Hz. The dispersive phase velocities were inverted to obtain crustal structures with a minimal number of layers. The resulting velocity models are similar for the northern and southern parts of the volcano. After geometrical spreading corrections, Q2Hz=14 and Q3Hz=31 were determined along the northern linear array. The typical low velocities and low Q corresponding to the cone structure and are similar to those of other basaltic volcanoes like Puu Oo, Hawaii, and Klyuchevskoy, Kamchatka.

  1. A distinct source and differentiation history for Kolumbo submarine volcano, Santorini volcanic field, Aegean arc.

    Science.gov (United States)

    Klaver, Martijn; Carey, Steven; Nomikou, Paraskevi; Smet, Ingrid; Godelitsas, Athanasios; Vroon, Pieter

    2016-08-01

    This study reports the first detailed geochemical characterization of Kolumbo submarine volcano in order to investigate the role of source heterogeneity in controlling geochemical variability within the Santorini volcanic field in the central Aegean arc. Kolumbo, situated 15 km to the northeast of Santorini, last erupted in 1650 AD and is thus closely associated with the Santorini volcanic system in space and time. Samples taken by remotely-operated vehicle that were analyzed for major element, trace element and Sr-Nd-Hf-Pb isotope composition include the 1650 AD and underlying K2 rhyolitic, enclave-bearing pumices that are nearly identical in composition (73 wt.% SiO2, 4.2 wt.% K2O). Lava bodies exposed in the crater and enclaves are basalts to andesites (52-60 wt.% SiO2). Biotite and amphibole are common phenocryst phases, in contrast with the typically anhydrous mineral assemblages of Santorini. The strong geochemical signature of amphibole fractionation and the assimilation of lower crustal basement in the petrogenesis of the Kolumbo magmas indicates that Kolumbo and Santorini underwent different crustal differentiation histories and that their crustal magmatic systems are unrelated. Moreover, the Kolumbo samples are derived from a distinct, more enriched mantle source that is characterized by high Nb/Yb (>3) and low (206)Pb/(204)Pb (<18.82) that has not been recognized in the Santorini volcanic products. The strong dissimilarity in both petrogenesis and inferred mantle sources between Kolumbo and Santorini suggests that pronounced source variations can be manifested in arc magmas that are closely associated in space and time within a single volcanic field.

  2. Design of SuSI - superconducting source for ions at NSCL/MSU - II. The conventional parts

    Energy Technology Data Exchange (ETDEWEB)

    Zavodszky, P.A. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States)]. E-mail: zavodszky@nscl.msu.edu; Arend, B. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States); Cole, D. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States); DeKamp, J. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States); Machicoane, G. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States); Marti, F. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States); Miller, P. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States); Moskalik, J. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States); Ottarson, J. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States); Vincent, J. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States); Zeller, A. [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron Road, East Lansing, MI 48824 (United States)

    2005-12-15

    An ECR ion source is being designed to initially serve as a test bench for development and later will replace the existing 6.4 GHz SC-ECRIS. This ECRIS will operate at 18 + 14.5 GHz microwave frequencies. The radial magnetic field will be produced by six superconducting hexapole coils, capable to reach 1.5 T at the aluminum plasma chamber wall (R = 50 mm). The axial trapping will be produced with six superconducting solenoids enclosed in an iron yoke. We will present the conventional parts of this ion source design: plasma chamber, injection and extraction hardware design and principles of the associated test beamline.

  3. Noise source localization using Matched Field Processing: wind turbines, mofettes and geysirs.

    Science.gov (United States)

    Umlauft, Josefine; Flores Estrella, Hortencia; Christin Obermann, Anne; Korn, Michael

    2017-04-01

    The Matched Field Processing (MFP) is a beamforming method, derived from ocean acoustics, that serves as a noise source localization and exploration tool in applied geophysics. Here, we present three case studies to explore the applicability of MFP in the presence of different source types, and using sensor arrays with different aperture and density. First, we show the localization of a single wind turbine (Saxony, Eastern Germany), which acts as a point source at the surface generating continuous vibrations due to the rotation of their blades. Using 30 vertical sensors (Reftek Texans) randomly distributed within an area of approximately 50 x 50 m2 around the wind turbine, we identified the turbine as the dominant noise source within the array. Therefore we verified that the MFP procedure gives useful results. The second test was performed in Hartouŝov (NW Bohemia, Czech Republic). This area is characterized by several natural degassing areas of mantle-originating fluids and CO2 (mofettes). Mofettes either appear as little sinks filled with bubbling groundwater or more extensive as vegetation anomalies. We located these mofettes, using the collapsing water bubbles as seismic noise source, and compared our results with CO2 flux values of the same field measured by Nickschick et al. (2015). The array consisted of 130 stations in total (30 Reftek Texans, 50 Omnirecs Data-Cubes3 and 50 Summit X-One channels) and covered an area of about 500 x 1000 m2. Additionally to MFP, we perfomed a polarization analysis of surface waves to characterize the wave field generated by the the degassing process. The last example is a geysering system in NE Java (Indonesia) which is called LUSI (Lumpur Sidoarjo). The geysir was surrounded by 5 stations (Trillium Compacts) arranged in a circle with about 1.5 km diameter. Here, we could successfully locate the surface position of the geysir as well as image its feeding channel to a depth of 100 m. This example shows the suitability of MFP

  4. Status of the High Brilliance Synchrotron Light Source BESSY-II

    Science.gov (United States)

    Jaeschke, E.

    1997-05-01

    The construction of BESSY-II at Berlin-Adlershof has entered the decisive phase: The injector complex comprising a 50 MeV racetrack microtron and a booster synchrotron with 10 Hz repetition rate and a final energy of 1.9 GeV has been set up ready for commissioning in the 2nd quarter of 1997. All major storage ring components are in house and the assembly of the 240 m DBA storage ring in 16-fold symmetry has started. Stored beam is expected for the 2nd quarter of 1998. The paper describes the status of the project.

  5. A New Algorithm for Joint Range-DOA-Frequency Estimation of Near-Field Sources

    Directory of Open Access Journals (Sweden)

    Jian-Feng Chen

    2004-03-01

    Full Text Available This paper studies the joint estimation problem of ranges, DOAs, and frequencies of near-field narrowband sources and proposes a new computationally efficient algorithm, which employs a symmetric uniform linear array, uses eigenvalues together with the corresponding eigenvectors of two properly designed matrices to estimate signal parameters, and does not require searching for spectral peak or pairing among parameters. In addition, the proposed algorithm can be applied in arbitrary Gaussian noise environment since it is based on the fourth-order cumulants, which is verified by extensive computer simulations.

  6. Filtered x-ray diode diagnostics fielded on the Z-accelerator for source power measurements

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, G.A.; Deeney, C.; Cuneo, M. [and others

    1998-06-02

    Filtered x-ray diode, (XRD), detectors are used as primary radiation flux diagnostics on Sandia`s Z-accelerator, which generates nominally a 200 TW, 2 MJ, x-ray pulse. Given such flux levels and XRD sensitivities the detectors are being fielded 23 meters from the source. The standard diagnostic setup and sensitivities are discussed. Vitreous carbon photocathodes are being used to reduce the effect of hydrocarbon contamination present in the Z-machine vacuum system. Nevertheless pre- and post-calibration data taken indicate spectrally dependent changes in the sensitivity of these detectors by up to factors up to 2 or 3.

  7. Creation and recovery of a W(111) single atom gas field ion source.

    Science.gov (United States)

    Pitters, Jason L; Urban, Radovan; Wolkow, Robert A

    2012-04-21

    Tungsten single atom tips have been prepared from a single crystal W(111) oriented wire using the chemical assisted field evaporation and etching method. Etching to a single atom tip occurs through a symmetric structure and leads to a predictable last atom unlike etching with polycrystalline tips. The single atom tip formation procedure is shown in an atom by atom removal process. Rebuilds of single atom tips occur on the same crystalline axis as the original tip such that ion emission emanates along a fixed direction for all tip rebuilds. This preparation method could be utilized and developed to prepare single atom tips for ion source development.

  8. Robust algorithm of direction of arrival estimation for coherent wideband sources in unknown correlated noise fields

    Institute of Scientific and Technical Information of China (English)

    TENG Pengxiao; MA Chizhou; YANG Yichun; LI Xiaodong

    2007-01-01

    A robust algorithm of direction of arrival (DOA) estimation for coherent wideband sources in unknown correlated noise fields was investigated. The noise is usually unknown and correlated among sensors in practical applications, especially for arrays with comparatively small apertures. The spatially correlated noise incurs an increase in focusing error and a severe degradation in the DOA estimation, and therefore a method of focusing transformation based on differentiating covariance matrix was proposed to eliminate noise, hence reduce the focusing error. The simulation and experimental results demonstrate the effectiveness of the proposed method.

  9. Preliminary study on the source field mode of geomagnetic six-month-period variations

    Institute of Scientific and Technical Information of China (English)

    陈伯舫; 冯戬云

    1997-01-01

    The monthly means of north component X of geomagnetic field from 16 observatories during 1984-1988 were analyzed using the Sompi spectral analysis technique. Most of these observatories are located in China. The analysis of the semiannual variations indicates that the latitude has no apparent effect on the X component. This clearly implies that the source field mode of semiannual variations cannot simply be described by using the P°1 mode. Using the P°1 mode to estimate the inductive scale length C in the semiannual period, the value of C at each observatory would be biased significantly. The purpose of this study is to find which kind of modes is optimal for estimating the values of C corresponding to the semiannual variations. The results show that a composite mode, involving five terms P°n(n = 1,....,5), might be a reasonable and acceptable one.

  10. Near-UV Sources in the Hubble Ultra Deep Field: The Catalog

    CERN Document Server

    Voyer, Elysse N; Siana, Brian; Gardner, Jonathan P; Quirk, Cori; Teplitz, Harry I

    2009-01-01

    The catalog from the first high resolution U-band image of the Hubble Ultra Deep Field, taken with Hubble's Wide Field Planetary Camera 2 through the F300W filter, is presented. We detect 96 U-band objects and compare and combine this catalog with a Great Observatories Origins Deep Survey (GOODS) B-selected catalog that provides B, V, i, and z photometry, spectral types, and photometric redshifts. We have also obtained Far-Ultraviolet (FUV, 1614 \\AA) data with Hubble's Advanced Camera for Surveys Solar Blind Channel (ACS/SBC) and with Galaxy Evolution Explorer (GALEX). We detected 31 sources with ACS/SBC, 28 with GALEX/FUV, and 45 with GALEX/NUV. The methods of observations, image processing, object identification, catalog preparation, and catalog matching are presented.

  11. Numerical correction of coherence gate in full-field swept-source interference microscopy.

    Science.gov (United States)

    Grebenyuk, Anton A; Ryabukho, Vladimir P

    2012-07-01

    A big problem in low-coherence interference microscopy is the degradation of the coherence signal caused by shift of the angular and temporal spectrum gates. It limits the depth of field in confocal optical coherence microscopy and degrades images of sample inner structure in most interference microscopy techniques. To overcome this problem we propose numerical correction of the coherence gate in application to full-field swept-source interference microscopy. The proposed technique allows three-dimensional sample imaging without mechanical movement of the microscope components and is also capable of determining separately the geometrical thickness and the refractive index of the sample layers, when the sample contains a transversal pattern. The applicability of the proposed technique is verified with numerical simulation.

  12. Near field acoustic holography based on the equivalent source method and pressure-velocity transducers

    DEFF Research Database (Denmark)

    Zhang, Y.-B.; Chen, X.-Z.; Jacobsen, Finn

    2009-01-01

    on particle velocity input data than when it is based on measurements of sound pressure data, and this is confirmed by a simulation study and by experimental results. A method that combines pressure- and particle velocity-based reconstructions in order to distinguish between contributions to the sound field......The advantage of using the normal component of the particle velocity rather than the sound pressure in the hologram plane as the input of conventional spatial Fourier transform based near field acoustic holography (NAH) and also as the input of the statistically optimized variant of NAH has...... recently been demonstrated. This paper examines whether there might be a similar advantage in using the particle velocity as the input of NAH based on the equivalent source method (ESM). Error sensitivity considerations indicate that ESM-based NAH is less sensitive to measurement errors when it is based...

  13. Folded Fields as the Source of Extreme Radio-Wave Scattering in the Galactic Center

    CERN Document Server

    Goldreich, P; Goldreich, Peter

    2006-01-01

    A strong case has been made that radio waves from sources within about half a degree of the Galactic Center undergo extreme diffractive scattering. However, problems arise when standard (``Kolmogorov'') models of electron density fluctuations are employed to interpret the observations of scattering in conjunction with those of free-free radio emission. Specifically, the outer scale of a Kolmogorov spectrum of electron density fluctuations is constrained to be so small that it is difficult to identify an appropriate astronomical setting. Moreover, an unacceptably high turbulent heating rate results if the outer scale of the velocity field coincides with that of the density fluctuations. We propose an alternative model based on folded magnetic field structures that have been reported in numerical simulations of small-scale dynamos. Nearly isothermal density variations across thin current sheets suffice to account for the scattering. There is no problem of excess turbulent heating because the outer scale for the...

  14. The fields of reference stars for optical positional observations of astrometric extragalactic radio sources

    Science.gov (United States)

    Dement'eva, A. A.; Ryl'Kov, V. P.

    The Pulkovo programme (Pul ERS) and the techniques used to create a catalogue of coordinates and magnitudes for more than 7000 faint stars in 73 small fields around extragalactic radiosources (ERS) are described. Accurate positions of stars in the fields around ERS 2200+420 and ERS 2021+614 are given. The catalogue containing 223 stars is presented. The errors of coordinate reductions in the system of reference stars from the CMC catalogue are found to be 1.5-2.0 times smaller than for those in the system of the PPM catalogue. This programme (Pul ERS) is required for quick identification of the extragalactic radio sources and for obtaining their characteristics from observations with large telescopes and CCD detectors.

  15. Near-UV Sources in the Hubble Ultra Deep Field: The Catalog

    Science.gov (United States)

    Gardner, Jonathan P.; Voyrer, Elysse; de Mello, Duilia F.; Siana, Brian; Quirk, Cori; Teplitz, Harry I.

    2009-01-01

    The catalog from the first high resolution U-band image of the Hubble Ultra Deep Field, taken with Hubble s Wide Field Planetary Camera 2 through the F300W filter, is presented. We detect 96 U-band objects and compare and combine this catalog with a Great Observatories Origins Deep Survey (GOODS) B-selected catalog that provides B, V, i, and z photometry, spectral types, and photometric redshifts. We have also obtained Far-Ultraviolet (FUV, 1614 Angstroms) data with Hubble s Advanced Camera for Surveys Solar Blind Channel (ACS/SBC) and with Galaxy Evolution Explorer (GALEX). We detected 31 sources with ACS/SBC, 28 with GALEX/FUV, and 45 with GALEX/NUV. The methods of observations, image processing, object identification, catalog preparation, and catalog matching are presented.

  16. The new high field photoexcitation muon spectrometer at the ISIS pulsed neutron and muon source

    CERN Document Server

    Yokoyama, K; Murahari, P; Wang, K; Dunstan, D J; Waller, S P; McPhail, D J; Hillier, A D; Henson, J; Harper, M R; Heathcote, P; Drew, A J

    2016-01-01

    A high power pulsed laser system has been installed on the high magnetic field muon instrument (HiFi) at the ISIS pulsed neutron and muon source, situated at the STFC Rutherford Appleton Laboratory in the UK. The upgrade enables one to perform light-pump muon-probe experiments under a high field, which opens up a brand-new area in the muon spin spectroscopy. In this report we overview the principle of the HiFi Laser system, and describe the newly developed techniques and devices that enable a controlled photoexcitation in the muon instrument. A demonstration experiment illustrates the unique combination of the photoexcited system and avoided level crossing technique.

  17. Field-scale operation of methane biofiltration systems to mitigate point source methane emissions

    Energy Technology Data Exchange (ETDEWEB)

    Hettiarachchi, Vijayamala C. [Centre for Environmental Engineering Research and Education (CEERE), Schulich School of Engineering, University of Calgary, Calgary, AB, T2N 1N4 (Canada); Hettiaratchi, Patrick J., E-mail: jhettiar@ucalgary.ca [Centre for Environmental Engineering Research and Education (CEERE), Schulich School of Engineering, University of Calgary, Calgary, AB, T2N 1N4 (Canada); Mehrotra, Anil K. [Centre for Environmental Engineering Research and Education (CEERE), Schulich School of Engineering, University of Calgary, Calgary, AB, T2N 1N4 (Canada); Kumar, Sunil, E-mail: sunil_neeri@yahoo.co.in [Centre for Environmental Engineering Research and Education (CEERE), Schulich School of Engineering, University of Calgary, Calgary, AB, T2N 1N4 (Canada)

    2011-06-15

    Methane biofiltration (MBF) is a novel low-cost technique for reducing low volume point source emissions of methane (CH{sub 4}). MBF uses a granular medium, such as soil or compost, to support the growth of methanotrophic bacteria responsible for converting CH{sub 4} to carbon dioxide (CO{sub 2}) and water (H{sub 2}O). A field research program was undertaken to evaluate the potential to treat low volume point source engineered CH{sub 4} emissions using an MBF at a natural gas monitoring station. A new comprehensive three-dimensional numerical model was developed incorporating advection-diffusive flow of gas, biological reactions and heat and moisture flow. The one-dimensional version of this model was used as a guiding tool for designing and operating the MBF. The long-term monitoring results of the field MBF are also presented. The field MBF operated with no control of precipitation, evaporation, and temperature, provided more than 80% of CH{sub 4} oxidation throughout spring, summer, and fall seasons. The numerical model was able to predict the CH{sub 4} oxidation behavior of the field MBF with high accuracy. The numerical model simulations are presented for estimating CH{sub 4} oxidation efficiencies under various operating conditions, including different filter bed depths and CH{sub 4} flux rates. The field observations as well as numerical model simulations indicated that the long-term performance of MBFs is strongly dependent on environmental factors, such as ambient temperature and precipitation. - Highlights: > One-dimensional version of the model was used as a guiding tool for designing and operating the MBF. > Mathematical model predicted CH{sub 4} oxidation behaviors of the field MBF with high accuracy i.e. (> 80 %). > Performance of MBF is dependent on ambient temperature and precipitation. - The developed numerical model simulations and field observations for estimating CH{sub 4} oxidation efficiencies under various operating conditions indicate that

  18. NuSTAR, XMM-Newton and Suzaku Observations of the Ultraluminous X-ray Source Holmberg II X-1

    CERN Document Server

    Walton, D J; Rana, V; Miller, J M; Harrison, F A; Fabian, A C; Bachetti, M; Barret, D; Boggs, S E; Christensen, F E; Craig, W W; Fuerst, F; Grefenstette, B W; Hailey, C J; Madsen, K K; Stern, D; Zhang, W

    2015-01-01

    We present the first broadband 0.3-25.0 kev X-ray observations of the extreme ultraluminous X-ray source (ULX) Holmberg II X-1, performed by NuSTAR, XMM-Newton and Suzaku in September 2013. The NuSTAR data provide the first observations of Holmberg II X-1 above 10 keV, and reveal a very steep high-energy spectrum, similar to other ULXs observed by NuSTAR to date. This implies that Holmberg II X-1 accretes at a high fraction of its Eddington accretion rate, and possibly exceeds it. The soft X-ray spectrum (E<10 keV) appears to be dominated by two blackbody-like emission components, the hotter of which may be associated with an accretion disk. However, all such models under-predict the NuSTAR data above ~10 keV, implying the presence of an additional emission component at the highest energies probed. We investigate plausible physical origins for this component, and favor a scenario in which the excess arises from Compton scattering in a hot corona of electrons with some properties similar to the very-high st...

  19. LOFAR low-band antenna observations of the 3C 295 and Boötes fields: source counts and ultra-steep spectrum sources

    Energy Technology Data Exchange (ETDEWEB)

    Van Weeren, R. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Williams, W. L.; Röttgering, H. J. A.; Rafferty, D. A.; Van der Tol, S. [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Tasse, C. [Department of Physics and Electronics, Rhodes University, P.O. Box 94, Grahamstown 6140 (South Africa); Heald, G. [Netherlands Institute for Radio Astronomy (ASTRON), P.O. Box 2, NL-7990 AA Dwingeloo (Netherlands); White, G. J. [Department of Physics and Astronomy, The Open University, Buckinghamshire MK7 6AA (United Kingdom); Shulevski, A. [Kapteyn Astronomical Institute, P.O. Box 800, NL-9700 AV Groningen (Netherlands); Best, P. [Institute for Astronomy, University of Edinburgh, Royal Observatory of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Intema, H. T.; Bhatnagar, S. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Reich, W. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Steinmetz, M. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Van Velzen, S. [Department of Astrophysics, Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud University Nijmegen, P.O. Box 9010, NL-6500 GL Nijmegen (Netherlands); Enßlin, T. A. [Max Planck Institute for Astrophysics, Karl-Schwarzschildstrasse 1, D-85748 Garching (Germany); Prandoni, I.; Brunetti, G. [INAF—Istituto di Radioastronomia, Via Gobetti 101, I-40129 Bologna (Italy); De Gasperin, F. [Hamburger Sternwarte, University of Hamburg, Gojenbergsweg 112, D-21029 Hamburg (Germany); Jamrozy, M., E-mail: rvanweeren@cfa.harvard.edu [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Kraków (Poland); and others

    2014-10-01

    We present Low Frequency Array (LOFAR) Low Band observations of the Boötes and 3C 295 fields. Our images made at 34, 46, and 62 MHz reach noise levels of 12, 8, and 5 mJy beam{sup –1}, making them the deepest images ever obtained in this frequency range. In total, we detect between 300 and 400 sources in each of these images, covering an area of 17-52 deg{sup 2}. From the observations, we derive Euclidean-normalized differential source counts. The 62 MHz source counts agree with previous GMRT 153 MHz and Very Large Array 74 MHz differential source counts, scaling with a spectral index of –0.7. We find that a spectral index scaling of –0.5 is required to match up the LOFAR 34 MHz source counts. This result is also in agreement with source counts from the 38 MHz 8C survey, indicating that the average spectral index of radio sources flattens toward lower frequencies. We also find evidence for spectral flattening using the individual flux measurements of sources between 34 and 1400 MHz and by calculating the spectral index averaged over the source population. To select ultra-steep spectrum (α < –1.1) radio sources that could be associated with massive high-redshift radio galaxies, we compute spectral indices between 62 MHz, 153 MHz, and 1.4 GHz for sources in the Boötes field. We cross-correlate these radio sources with optical and infrared catalogs and fit the spectral energy distribution to obtain photometric redshifts. We find that most of these ultra-steep spectrum sources are located in the 0.7 ≲ z ≲ 2.5 range.

  20. Systematic review of biological effects of exposure to static electric fields. Part II: Invertebrates and plants.

    Science.gov (United States)

    Schmiedchen, Kristina; Petri, Anne-Kathrin; Driessen, Sarah; Bailey, William H

    2017-09-27

    The construction of high-voltage direct current (HVDC) lines for the long-distance transport of energy is becoming increasingly popular. This has raised public concern about potential environmental impacts of the static electric fields (EF) produced under and near HVDC power lines. As the second part of a comprehensive literature analysis, the aim of this systematic review was to assess the effects of static EF exposure on biological functions in invertebrates and plants and to provide the basis for an environmental impact assessment of such exposures. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was used to guide the methodological conduct and reporting. Thirty-three studies - 14 invertebrate and 19 plant studies - met the eligibility criteria and were included in this review. The reported behavioral responses of insects and planarians upon exposure strongly suggest that invertebrates are able to perceive the presence of a static EF. Many other studies reported effects on physiological functions that were expressed as, for example, altered metabolic activity or delayed reproductive and developmental stages in invertebrates. In plants, leaf damage, alterations in germination rates, growth and yield, or variations in the concentration of essential elements, for example, have been reported. However, these physiological responses and changes in plant morphology appear to be secondary to surface stimulation by the static EF or caused by concomitant parameters of the electrostatic environment. Furthermore, all of the included studies suffered from methodological flaws, which lowered credibility in the results. At field levels encountered from natural sources or HVDC lines (effects of static EF on other biological functions in invertebrates and plants. At far higher field levels (> 35kV/m), adverse effects on physiology and morphology, presumably caused by corona-action, appear to be more likely. Higher quality studies are needed to

  1. FIRST "Winged" and X-shaped Radio Source Candidates: II. New Redshifts

    CERN Document Server

    Cheung, C C; Landt, Hermine; Kleijn, Gijs Verdoes; Jordán, Andrés

    2008-01-01

    We report optical spectroscopic observations of X-shaped radio sources with the Hobby-Eberly Telescope and Multiple-Mirror Telescope, focused on the sample of candidates from the FIRST survey presented in Paper I (Cheung 2007). A total of 27 redshifts were successfully obtained, 21 of which are new, including that of a newly identified candidate source of this type which is presented here. With these observations, the sample of candidates from Paper I is over 50% spectroscopically identified. Two new broad emission-lined X-shaped radio sources are revealed, while no emission lines were detected in about one third of the observed sources; a detailed study of the line properties is deferred to a future paper. Finally, to explore their relation to the Fanaroff-Riley division, the radio luminosities and host galaxy absolute magnitudes of a spectroscopically identified sample of 50 X-shaped radio galaxies are calculated to determine their placement in the Owen-Ledlow plane.

  2. Sources of Mesoscale Variability of Gravity Waves. Part II: Frontal, Convective, and Jet Stream Excitation.

    Science.gov (United States)

    Fritts, David C.; Nastrom, Gregory D.

    1992-01-01

    We present studies of four cases of mesoscale variance enhancements of horizontal velocity and temperature due to frontal activity, nonfrontal convection, and wind shear. These data were obtained aboard commercial aircraft during the Global Atmospheric Sampling Program (GASP) in 1978 and 1979 and from the corresponding meteorological analyses and satellite imagery. Additional GASP data were used to permit a statistical assessment of the importance of various sources of enhanced variances. Our results, and those in a companion paper addressing the variance enhancements associated with topography, represent refinements of previous source analyses using the GASP dataset. Significant findings include mean variance enhancements of velocity and temperature due to convection and jet-stream flow ranging from 2 to 8 for 64-km and 256-km data segments, and enhancements for individual segments as high as 20 to 100. The mean 64-km variance enhancement for all variables and source types, relative to a quiescent background, was estimated to be 6.1. These results suggest a major role for localized sources in energizing the mesoscale motion spectrum at horizontal scales < 100 km, and correspondingly greater influences for such motions at greater heights.

  3. VizieR Online Data Catalog: Optically Bright extragalactic Radio Sources II (Petrov, 2013)

    Science.gov (United States)

    Petrov, L.

    2014-06-01

    The first VLBI (Very Long Baseline Interferometry) observing campaign in 2007 resulted in the detection of 398 targets with the European VLBI Network (EVN; Bourda et al., 2010, cat. J/A+A/520/A113). During the second observing campaign, a subset of 105 sources detected in the previous campaign was observed (Bourda et al., 2011, cat. J/A+A/526/A102). Their positions were derived by Petrov (2011, cat. J/AJ/142/105) and formed the OBRS-1 (Optically Bright extragalactic Radio Sources) catalog. The remaining sources were observed in the third campaign, called OBRS-2. During the OBRS-2 campaign, there were three observing sessions with 10 VLBA (Very Long Baseline Array) stations and 5-6 EVN stations from this list: EFLSBERG, MEDICINA, ONSALA60, YEBES40M, DSS63, HARTRAO, and NOTO. Observations were made on 2010 Mar 23 (session ID gc034a), on 2011 Nov 8 (gc034bcd), and on 2011 Mar 15 (gc034ef). The OBRS-2 catalog presents precise positions of the 295 extragalactic radio sources as well as median correlated flux densities at 8.4 and 2.2GHz at baseline lengths shorter than 900km and at baseline lengths longer than 5000km. (1 data file).

  4. FIRST "WINGED" AND X-SHAPED RADIO SOURCE CANDIDATES. II. NEW REDSHIFTS

    NARCIS (Netherlands)

    Cheung, C. C.; Healey, Stephen E.; Landt, Hermine; Kleijn, Gijs Verdoes; Jordan, Andres

    2009-01-01

    We report optical spectroscopic observations of X-shaped radio sources with the Hobby-Eberly Telescope and Multiple-Mirror Telescope, focused on the sample of candidates from the FIRST survey presented in a previous paper. A total of 27 redshifts were successfully obtained, 21 of which are new, incl

  5. Immobilized Tannin from Sanseviera trifasciata on Carbon as Adsorbent For Iron(II in Polluted Water Source

    Directory of Open Access Journals (Sweden)

    Irfan Hanafi Arif

    2016-03-01

    Full Text Available The organic-agricultural waste resulted from local farmer or community gardening recently paid public attention. The presence and easily grown of “Lidah Mertua” or Sanseviera trifasciata being focused on potency investigation for its prospecting application. It was reported contain some phenolic and also tannin extracted from aqueous solvents. This paper revealed recent investigation applying of its isolated tannin from leave part to modifying of activated carbon. The previous report published that carbon were able to adsorb some toxic heavy metals. However, it has some limitation including lower capacity adsorption. Impregnated or immobilized the tannin-isolated from S. trifasciata leaves was able to modify the carbon functionality, physical appearance, pores size, and it adsorption capacity. Both Langmuir and Freundlich adsorption mechanism model also disclosed the developed adsorbent mechanism of iron(II adsorption on the adsorbent tannin-immobolized on carbon. The real test using community well drilling water source also gave important finding on the concentration of iron(II contained on water source.

  6. The Neutron Energy Spectrum Study from the Phase II Solid Methane Moderator at the LENS Neutron Source

    CERN Document Server

    Shin, Yunchang; Lavelle, Christopher M; Baxter, David V; Tong, Xin; Yan, Haiyang; Leuschner, Mark

    2007-01-01

    Neutron energy spectrum measurements from a solid methane moderator were performed at the Low Energy Neutron Source (LENS) at Indiana University Cyclotron Facility (IUCF) to verify our neutron scattering model of solid methane. The time-of-flight method was used to measure the energy spectrum of the moderator in the energy range of 0.1$meV\\sim$ 1$eV$. Neutrons were counted with a high efficiency $^{3}{He}$ detector. The solid methane moderator was operated in phase II temperature and the energy spectra were measured at the temperatures of 20K and 4K. We have also tested our newly-developed scattering kernels for phase II solid methane by calculating the neutron spectral intensity expected from the methane moderator at the LENS neutron source using MCNP (Monte Carlo N-particle Transport Code). Within the expected accuracy of our approximate approach, our model predicts both the neutron spectral intensity and the optimal thickness of the moderator at both temperatures. The predictions are compared to the measur...

  7. DEEP GALEX UV SURVEY OF THE KEPLER FIELD. I. POINT SOURCE CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    Olmedo, Manuel; Chávez, Miguel; Bertone, Emanuele [Instituto Nacional de Astrofísica Optica y Electrónica Luis Enrique Erro #1, CP 72840, Tonantzintla, Puebla (Mexico); Lloyd, James [Department of Astronomy, Cornell University, Ithaca, NY (United States); Mamajek, Eric E. [University of Rochester, Department of Physics and Astronomy, Rochester, NY 14627-0171 (United States); Martin, D. Christopher; Neill, James D., E-mail: olmedo@inaoep.mx [California Institute of Technology, 1200 East California Boulevard, MC 278-17, Pasadena, CA 91125 (United States)

    2015-11-10

    We report observations of a deep near-ultraviolet (NUV) survey of the Kepler field made in 2012 with the Galaxy Evolution Explorer (GALEX) Complete All-Sky UV Survey Extension (CAUSE). The GALEX-CAUSE Kepler survey (GCK) covers 104 square degrees of the Kepler field and reaches a limiting magnitude of NUV ≃ 22.6 at 3σ. Analysis of the GCK survey has yielded a catalog of 669,928 NUV sources, of which 475,164 are cross-matched with stars in the Kepler Input Catalog. Approximately 327 of 451 confirmed exoplanet host stars and 2614 of 4696 candidate exoplanet host stars identified by Kepler have NUV photometry in the GCK survey. The GCK catalog should enable the identification and characterization of UV-excess stars in the Kepler field (young solar-type and low-mass stars, chromospherically active binaries, white dwarfs, horizontal branch stars, etc.), and elucidation of various astrophysics problems related to the stars and planetary systems in the Kepler field.

  8. Effect of an electric field on superfluid helium scintillation produced by alpha-particle sources

    CERN Document Server

    Ito, T M; Ramsey, J; Karcz, M; Liu, C -Y; Long, J C; Reddy, T G; Seidel, G M

    2012-01-01

    We report a study of the intensity and time dependence of scintillation produced by weak alpha particle sources in superfluid helium in the presence of an electric field (0 - 45 kV/cm) in the temperature range of 0.2 K to 1.1 K at the saturated vapor pressure. Both the prompt and the delayed components of the scintillation exhibit a reduction in intensity with the application of an electric field. The reduction in the intensity of the prompt component is well approximated by a linear dependence on the electric field strength with a reduction of 15% at 45 kV/cm. When analyzed using the Kramers theory of columnar recombination, this electric field dependence leads to the conclusion that roughly 40% of the scintillation results from species formed from atoms originally promoted to excited states and 60% from excimers created by ionization and subsequent recombination with the charges initially having a cylindrical Gaussian distribution about the alpha track of 60 nm radius. The intensity of the delayed component...

  9. Properties of the Scuba-2 850 μm Sources in the XMM-LSS Field

    Science.gov (United States)

    Seo, Hyunjong; Jeong, Woong-Seob; Kim, Seong Jin; Pyo, Jeonghyun; Kim, Min Gyu; Ko, Jongwan; Kim, Minjin; Kim, Sam

    2017-02-01

    We carry out the study of 850 μm sources in a part of the XMM-LSS field. The 850 μm imaging data were obtained by the SCUBA-2 on the James Clerk Maxwell Telescope(JCMT) for three days in July 2015 with an integration time of 6.1 hours, covering a circular area with a radius of 15'. We choose the central area up to a radius of 9.15 arcmin for the study, where the noise distribution is relatively uniform. The root mean square (rms) noise at the center is 2.7 mJy. We identify 17 sources with S/N > 3.5. Differential number count is estimated in flux range between 3.5 and 9.0 mJy after applying various corrections derived by imaging simulations, which is consistent with previous studies. For detailed study on the individual sources, we select three sources with more reliable measurements (S/N > 4.5), and construct their spectral energy distributions (SEDs) from optical to far-infrared band. Redshift distribution of the sources ranges from 0.36 to 3.28, and their physical parameters are extracted using MAGPHYS model, which yield infrared luminosity L_{IR}= 10^{11.3}-10^{13.4} L_{⊙}, star formation rate SFR = 10^{1.3}-10^{3.2} M_{⊙}yr^{-1} and dust temperature T_{D} = 30-53 K. We investigate the correlation between L_{IR} and T_{D}, which appears to be consistent with previous studies.}

  10. ELECTROMAGNETIC FIELD MEASUREMENT OF FUNDAMENTAL AND HIGHER-ORDER MODES FOR 7-CELL CAVITY OF PETRA-II

    Energy Technology Data Exchange (ETDEWEB)

    Kawashima, Y.; Blednykh, A.; Cupolo, J.; Davidsaver, M.; Holub, B.; Ma, H.; Oliva, J.; Rose, J.; Sikora, R.; Yeddulla, M.

    2011-03-28

    The booster synchrotron for NSLS-II will include a 7-cell PETRA cavity, which was manufactured for the PETRA-II project at DESY. The cavity fundamental frequency operates at 500 MHz. In order to verify the impedances of the fundamental and higher-order modes (HOM), which were calculated by computer code, we measured the magnitude of the electromagnetic field of the fundamental acceleration mode and HOM using the bead-pull method. To keep the cavity body temperature constant, we used a chiller system to supply cooling water at 20 degrees C. The bead-pull measurement was automated with a computer. We encountered some issues during the measurement process due to the difficulty in measuring the electromagnetic field magnitude in a multi-cell cavity. We describe the method and apparatus for the field measurement, and the obtained results.

  11. Deploying quantum light sources on nanosatellites II: lessons and perspectives on CubeSat spacecraft

    CERN Document Server

    Bedington, Robert; Chuan, Tan Yue; Cheng, Cliff; Durak, Kadir; Grieve, James Anthony; Larsen, Jesper; Oi, Daniel; Ling, Alexander

    2015-01-01

    To enable space-based quantum key distribution proposals the Centre for Quantum Technologies is developing a source of entangled photons ruggedized to survive deployment in space and greatly miniaturised so that it conforms to the strict form factor and power requirements of a 1U CubeSat. The Small Photon Entangling Quantum System is an integrated instrument where the pump, photon pair source and detectors are combined within a single optical tray and electronics package that is no larger than 10 cm x 10 cm x 3 cm. This footprint enables the instrument to be placed onboard nanosatellites or the CubeLab structure aboard the International Space Station. We will discuss the challenges and future prospects of CubeSat-based missions.

  12. Deploying quantum light sources on nanosatellites II: lessons and perspectives on CubeSat spacecraft

    Science.gov (United States)

    Bedington, R.; Truong-Cao, E.; Tan, Y. C.; Cheng, C.; Durak, K.; Grieve, J.; Larsen, J.; Oi, D.; Ling, A.

    2015-10-01

    To enable space-based quantum key distribution proposals the Centre for Quantum Technologies is developing a source of entangled photons ruggedized to survive deployment in space and greatly miniaturised so that it conforms to the strict form factor and power requirements of a 1U CubeSat. The Small Photon Entangling Quantum System is an integrated instrument where the pump, photon pair source and detectors are combined within a single optical tray and electronics package that is no larger than 10 cm x 10 cm x 3 cm. This footprint enables the instrument to be placed onboard nanosatellites or the CubeLab structure aboard the International Space Station. We will discuss the challenges and future prospects of CubeSat-based missions.

  13. Sources and sinks of formic, acetic, and pyruvic acids over central Amazonia. II - Wet season

    Science.gov (United States)

    Talbot, R. W.; Andreae, M. O.; Berresheim, H.; Jacob, D. J.; Beecher, K. M.

    1990-01-01

    Potential sources and sinks of formic, acetic, and pyruvic acids over the Amazon forest were investigated using a photochemical model and data collected on gas phase concentrations of these acids in the forest canopy, boundary layer, and free troposphere over the central Amazon Basin during the 1987 wet season. It was found that the atmospheric reactions previously suggested in the literature as sources of carboxylic acids (i.e., the gas phase decomposition of isoprene, the reaction between CH3CO3 and a peroxide, and aqueous phase oxidation of CH2O) appear to be too slow to explain the observed concentrations, suggesting that other atmospheric reactions, so far unidentified, could make a major contribution to the carboxylic acid budgets.

  14. Effects of reconstructed magnetic field from sparse noisy boundary measurements on localization of active neural source.

    Science.gov (United States)

    Shen, Hui-min; Lee, Kok-Meng; Hu, Liang; Foong, Shaohui; Fu, Xin

    2016-01-01

    Localization of active neural source (ANS) from measurements on head surface is vital in magnetoencephalography. As neuron-generated magnetic fields are extremely weak, significant uncertainties caused by stochastic measurement interference complicate its localization. This paper presents a novel computational method based on reconstructed magnetic field from sparse noisy measurements for enhanced ANS localization by suppressing effects of unrelated noise. In this approach, the magnetic flux density (MFD) in the nearby current-free space outside the head is reconstructed from measurements through formulating the infinite series solution of the Laplace's equation, where boundary condition (BC) integrals over the entire measurements provide "smooth" reconstructed MFD with the decrease in unrelated noise. Using a gradient-based method, reconstructed MFDs with good fidelity are selected for enhanced ANS localization. The reconstruction model, spatial interpolation of BC, parametric equivalent current dipole-based inverse estimation algorithm using reconstruction, and gradient-based selection are detailed and validated. The influences of various source depths and measurement signal-to-noise ratio levels on the estimated ANS location are analyzed numerically and compared with a traditional method (where measurements are directly used), and it was demonstrated that gradient-selected high-fidelity reconstructed data can effectively improve the accuracy of ANS localization.

  15. Definitions of database files and fields of the Personal Computer-Based Water Data Sources Directory

    Science.gov (United States)

    Green, J. Wayne

    1991-01-01

    This report describes the data-base files and fields of the personal computer-based Water Data Sources Directory (WDSD). The personal computer-based WDSD was derived from the U.S. Geological Survey (USGS) mainframe computer version. The mainframe version of the WDSD is a hierarchical data-base design. The personal computer-based WDSD is a relational data- base design. This report describes the data-base files and fields of the relational data-base design in dBASE IV (the use of brand names in this abstract is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey) for the personal computer. The WDSD contains information on (1) the type of organization, (2) the major orientation of water-data activities conducted by each organization, (3) the names, addresses, and telephone numbers of offices within each organization from which water data may be obtained, (4) the types of data held by each organization and the geographic locations within which these data have been collected, (5) alternative sources of an organization's data, (6) the designation of liaison personnel in matters related to water-data acquisition and indexing, (7) the volume of water data indexed for the organization, and (8) information about other types of data and services available from the organization that are pertinent to water-resources activities.

  16. Development of a Field-Aligned Integrated Conductivity Model Using the SAMI2 Open Source Code

    Science.gov (United States)

    Hildebrandt, Kyle; Gearheart, Michael; West, Keith

    2003-03-01

    The SAMI2 open source code is a middle and low latitude ionspheric model developed by the Naval Research Lab for the dual purposes of research and education. At the time of this writing the source code has no component for the integrated magnetic field-aligned conductivity. The dependence of human activities on conditions in the space environment, such as communications, has grown and will continue to do so. With this growth comes higher financial stakes, as changes in the space environment have greater economic impact. In order to minimize the adverse effects of these changes, predictive models are being developed. Among the geophysical parameters that affect communications is the conductivity in the ionosphere. As part of the commitment of Texas A & M Univeristy-Commerce to build a strong undergraduate research program, a team consisting of two students and a faculty mentor are developing a model of the integrated field-aligned conductivity using the SAMI2 code. The current status of the research and preliminary results are presented as well as a summary of future work.

  17. Source Attributions of Pollution to the Western Arctic During the NASA ARCTAS Field Campaign

    Science.gov (United States)

    Bian, H.; Colarco, P. R.; Chin, M.; Chen, G.; Rodriquez, J. M.; Liang, Q.; Blake, D.; Chu, D. A.; daSilva, A.; Darmenov, A. S.; Diskin. G.; Fuelberg, H. E.; Huey, G.; Kondo, Y.; Nielsen, J. E.; Pan, X.; Wisthaler, A.

    2013-01-01

    We use the NASA GEOS-5 transport model with tagged tracers to investigate the contributions of different regional sources of CO and black carbon (BC) to their concentrations in the Western Arctic (i.e., 50-90 deg N and 190- 320 deg E) in spring and summer 2008. The model is evaluated by comparing the results with airborne measurements of CO and BC from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) field campaigns to demonstrate the strengths and limitations of our simulations. We also examine the reliability of tagged CO tracers in characterizing air mass origins using the measured fossil fuel tracer of dichloromethane and the biomass burning tracer of acetonitrile. Our tagged CO simulations suggest that most of the enhanced CO concentrations (above background level from CH4 production) observed during April originate from Asian anthropogenic emissions. Boreal biomass burning emissions and Asian anthropogenic emissions are of similar importance in July domain wise, although the biomass burning CO fraction is much larger in the area of the ARCTAS field experiments. The fraction of CO from Asian anthropogenic emissions is larger in spring than in summer. European sources make up no more than 10% of CO levels in the campaign domain during either period. Comparisons of CO concentrations along the flight tracks with regional averages from GEOS-5 show that the alongtrack measurements are representative of the concentrations within the large domain of the Western Arctic in April but not in July.

  18. A systematic search for near-infrared counterparts of nearby ultraluminous X-ray sources (II)

    Science.gov (United States)

    López, K. M.; Heida, M.; Jonker, P. G.; Torres, M. A. P.; Roberts, T. P.; Walton, D. J.; Moon, D.-S.; Harrison, F. A.

    2017-07-01

    We present the results of our continued systematic search for near-infrared (NIR) candidate counterparts to ultraluminous X-ray sources (ULXs) within 10 Mpc. We observed 42 ULXs in 24 nearby galaxies and detected NIR candidate counterparts to 15 ULXs. Fourteen of these ULXs appear to have a single candidate counterpart in our images and the remaining ULX has two candidate counterparts. Seven ULXs have candidate counterparts with absolute magnitudes in the range between -9.26 and -11.18 mag, consistent with them being red supergiants (RSGs). The other eight ULXs have candidate counterparts with absolute magnitudes too bright to be a single stellar source. Some of these NIR sources show extended morphology or colours expected for active galactic nuclei (AGNs), strongly suggesting that they are likely stellar clusters or background galaxies. The RSG candidate counterparts form a valuable sample for follow-up spectroscopic observations to confirm their nature, with the ultimate goal of directly measuring the mass of the compact accretor that powers the ULX using binary Doppler shifts.

  19. Unveiling the nature of INTEGRAL objects through optical spectroscopy. II. The nature of four unidentified sources

    CERN Document Server

    Masetti, N; Bassani, L; Bird, A J; Maiorano, E; Malizia, A; Palazzi, E; Stephen, J B; Bazzano, A; Dean, A J; Ubertini, P; Walter, R

    2005-01-01

    We present the results of our optical spectrophotometric campaign ongoing at the Astronomical Observatory of Bologna in Loiano (Italy) on hard X-ray sources detected by INTEGRAL. We observed spectroscopically the putative optical counterparts of four more INTEGRAL sources, IGR J12391-1610, IGR J18406-0539, 2E 1853.7+1534 and IGR J19473+4452. These data have allowed us to determine their nature, finding that IGR J12391-1610 (=LEDA 170194) and IGR J19473+4452 are Seyfert 2 galaxies at redshifts z = 0.036 and z = 0.053, respectively, IGR J18406-0539 (=SS 406) is a Be massive X-ray binary located at about 1.1 kpc from Earth, and 2E 1853.7+1534 is a Type 1 Seyfert galaxy with z = 0.084. Physical parameters for these objects are also evaluated by collecting and discussing the available multiwavelength information. The determination of the extragalactic nature of a substantial fraction of sources inside the INTEGRAL surveys underlines the importance of hard X-ray observations for the study of background Active Galac...

  20. Probabilistic tsunami hazard assessment at Seaside, Oregon, for near- and far-field seismic sources

    Science.gov (United States)

    GonzáLez, F. I.; Geist, E. L.; Jaffe, B.; KâNoǧLu, U.; Mofjeld, H.; Synolakis, C. E.; Titov, V. V.; Arcas, D.; Bellomo, D.; Carlton, D.; Horning, T.; Johnson, J.; Newman, J.; Parsons, T.; Peters, R.; Peterson, C.; Priest, G.; Venturato, A.; Weber, J.; Wong, F.; Yalciner, A.

    2009-11-01

    The first probabilistic tsunami flooding maps have been developed. The methodology, called probabilistic tsunami hazard assessment (PTHA), integrates tsunami inundation modeling with methods of probabilistic seismic hazard assessment (PSHA). Application of the methodology to Seaside, Oregon, has yielded estimates of the spatial distribution of 100- and 500-year maximum tsunami amplitudes, i.e., amplitudes with 1% and 0.2% annual probability of exceedance. The 100-year tsunami is generated most frequently by far-field sources in the Alaska-Aleutian Subduction Zone and is characterized by maximum amplitudes that do not exceed 4 m, with an inland extent of less than 500 m. In contrast, the 500-year tsunami is dominated by local sources in the Cascadia Subduction Zone and is characterized by maximum amplitudes in excess of 10 m and an inland extent of more than 1 km. The primary sources of uncertainty in these results include those associated with interevent time estimates, modeling of background sea level, and accounting for temporal changes in bathymetry and topography. Nonetheless, PTHA represents an important contribution to tsunami hazard assessment techniques; viewed in the broader context of risk analysis, PTHA provides a method for quantifying estimates of the likelihood and severity of the tsunami hazard, which can then be combined with vulnerability and exposure to yield estimates of tsunami risk.

  1. Clustering Properties of Far-Infrared Sources in Hi-GAL Science Demonstration Phase Fields

    CERN Document Server

    Billot, N; Pestalozzi, M; Molinari, S; Noriega-Crespo, A; Mottram, J C; Anderson, L D; Elia, D; Stringfellow, G; Thompson, M A; Polychroni, D; Testi, L

    2011-01-01

    We use a Minimum Spanning Tree algorithm to characterize the spatial distribution of Galactic Far-IR sources and derive their clustering properties. We aim to reveal the spatial imprint of different types of star forming processes, e.g. isolated spontaneous fragmentation of dense molecular clouds, or events of triggered star formation around HII regions, and highlight global properties of star formation in the Galaxy. We plan to exploit the entire Hi-GAL survey of the inner Galactic plane to gather significant statistics on the clustering properties of star forming regions, and to look for possible correlations with source properties such as mass, temperature or evolutionary stage. In this paper we present a pilot study based on the two 2x2 square degree fields centered at longitudes l=30 and l=59 obtained during the Science Demonstration Phase (SDP) of the Herschel mission. We find that over half of the clustered sources are associated with HII regions and infrared dark clouds. Our analysis also reveals a sm...

  2. CANDELS Multiwavelength catalogs: Source Identification and Photometry in the CANDELS UKIDSS Ultra-Deep Survey Field

    CERN Document Server

    Galametz, Audrey; Fontana, Adriano; Ferguson, Henry C; Ashby, M L N; Barro, Guillermo; Castellano, Marco; Dahlen, Tomas; Donley, Jennifer L; Faber, Sandy M; Grogin, Norman; Guo, Yicheng; Huang, Kuang-Han; Kocevski, Dale D; Koekemoer, Anton M; Lee, Kyoung-Soo; McGrath, Elizabeth J; Peth, Michael; Willner, S P; Almaini, Omar; Cooper, Michael; Cooray, Asantha Roshan; Conselice, Christopher J; Dickinson, Mark; Dunlop, James S; Fazio, G G; Foucaud, Sebastien; Gardner, Jonathan P; Giavalisco, Mauro; Hathi, N P; Hartley, Will G; Koo, David C; Lai, Kamson; de Mello, Duilia F; McLure, Ross J; Lucas, Ray A; Paris, Diego; Pentericci, Laura; Santini, Paola; Simpson, Chris; Sommariva, Veronica; Targett, Thomas; Weiner, Benjamin J; Wuyts, Stijn

    2013-01-01

    We present the multiwavelength - ultraviolet to mid-infrared - catalog of the UKIDSS Ultra-Deep Survey (UDS) field observed as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). Based on publicly available data, the catalog includes: the CANDELS data from the Hubble Space Telescope (near-infrared WFC3 F125W and F160W data and visible ACS F606W and F814W data), u-band data from CFHT/Megacam, B, V, Rc, i' and z' band data from Subaru/Suprime-Cam, Y and Ks band data from VLT/HAWK-I, J, H and K bands data from UKIDSS (Data Release 8), and Spitzer/IRAC data (3.6, 4.5 from SEDS, 5.8 and 8.0um from SpUDS). The present catalog is F160W-selected and contains 35932 sources over an area of 201.7 square arcmin and includes radio and X-ray detected sources and spectroscopic redshifts available for 210 sources.

  3. Open Drug Discovery Toolkit (ODDT): a new open-source player in the drug discovery field.

    Science.gov (United States)

    Wójcikowski, Maciej; Zielenkiewicz, Piotr; Siedlecki, Pawel

    2015-01-01

    There has been huge progress in the open cheminformatics field in both methods and software development. Unfortunately, there has been little effort to unite those methods and software into one package. We here describe the Open Drug Discovery Toolkit (ODDT), which aims to fulfill the need for comprehensive and open source drug discovery software. The Open Drug Discovery Toolkit was developed as a free and open source tool for both computer aided drug discovery (CADD) developers and researchers. ODDT reimplements many state-of-the-art methods, such as machine learning scoring functions (RF-Score and NNScore) and wraps other external software to ease the process of developing CADD pipelines. ODDT is an out-of-the-box solution designed to be easily customizable and extensible. Therefore, users are strongly encouraged to extend it and develop new methods. We here present three use cases for ODDT in common tasks in computer-aided drug discovery. Open Drug Discovery Toolkit is released on a permissive 3-clause BSD license for both academic and industrial use. ODDT's source code, additional examples and documentation are available on GitHub (https://github.com/oddt/oddt).

  4. Transmission type flat-panel X-ray source using ZnO nanowire field emitters

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Daokun; Song, Xiaomeng; Zhang, Zhipeng; Chen, Jun, E-mail: stscjun@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou 510275 (China); School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Li, Ziping [The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510275 (China); She, Juncong; Deng, Shaozhi; Xu, Ningsheng [State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou 510275 (China); School of Microelectronics, Sun Yat-sen University, Guangzhou 510275 (China)

    2015-12-14

    A transmission type flat-panel X-ray source in diode structure was fabricated. Large-scale patterned ZnO nanowires grown on a glass substrate by thermal oxidation were utilized as field emitters, and tungsten thin film coated on silica glass was used as the transmission anode. Uniform distribution of X-ray generation was achieved, which benefited from the uniform electron emission from ZnO nanowires. Self-ballasting effect induced by the intrinsic resistance of ZnO nanowire and decreasing of screening effect caused by patterned emitters account for the uniform emission. Characteristic X-ray peaks of W-L lines and bremsstrahlung X-rays have been observed under anode voltages at a range of 18–20 kV, the latter of which were the dominant X-ray signals. High-resolution X-ray images with spatial resolution less than 25 μm were obtained by the flat-panel X-ray source. The high resolution was attributed to the small divergence angle of the emitted X-rays from the transmission X-ray source.

  5. Probabilistic tsunami hazard assessment at Seaside, Oregon, for near-and far-field seismic sources

    Science.gov (United States)

    Gonzalez, F.I.; Geist, E.L.; Jaffe, B.; Kanoglu, U.; Mofjeld, H.; Synolakis, C.E.; Titov, V.V.; Areas, D.; Bellomo, D.; Carlton, D.; Horning, T.; Johnson, J.; Newman, J.; Parsons, T.; Peters, R.; Peterson, C.; Priest, G.; Venturato, A.; Weber, J.; Wong, F.; Yalciner, A.

    2009-01-01

    The first probabilistic tsunami flooding maps have been developed. The methodology, called probabilistic tsunami hazard assessment (PTHA), integrates tsunami inundation modeling with methods of probabilistic seismic hazard assessment (PSHA). Application of the methodology to Seaside, Oregon, has yielded estimates of the spatial distribution of 100- and 500-year maximum tsunami amplitudes, i.e., amplitudes with 1% and 0.2% annual probability of exceedance. The 100-year tsunami is generated most frequently by far-field sources in the Alaska-Aleutian Subduction Zone and is characterized by maximum amplitudes that do not exceed 4 m, with an inland extent of less than 500 m. In contrast, the 500-year tsunami is dominated by local sources in the Cascadia Subduction Zone and is characterized by maximum amplitudes in excess of 10 m and an inland extent of more than 1 km. The primary sources of uncertainty in these results include those associated with interevent time estimates, modeling of background sea level, and accounting for temporal changes in bathymetry and topography. Nonetheless, PTHA represents an important contribution to tsunami hazard assessment techniques; viewed in the broader context of risk analysis, PTHA provides a method for quantifying estimates of the likelihood and severity of the tsunami hazard, which can then be combined with vulnerability and exposure to yield estimates of tsunami risk. Copyright 2009 by the American Geophysical Union.

  6. X-ray Sources in the Hubble Deep Field Detected by Chandra

    CERN Document Server

    Hornschemeier, A E; Garmire, G P; Schneider, D P; Broos, P S; Townsley, L K; Bautz, M W; Burrows, D N; Chartas, G; Feigelson, E D; Griffiths, R; Lumb, D H; Nousek, J A; Sargent, W L W

    2000-01-01

    We present first results from an X-ray study of the Hubble Deep Field North (HDF-N) and its environs obtained using 166 ks of data collected by the Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-ray Observatory. This is the deepest X-ray observation ever reported, and in the HDF-N itself we detect six X-ray sources down to a 0.5--8 keV flux limit of 4E-16 erg cm^-2 s^-1. Comparing these sources with objects seen in multiwavelength HDF-N studies shows positional coincidences with the extremely red object NICMOS J123651.74 +621221.4, an active galactic nucleus (AGN), three elliptical galaxies, and one nearby spiral galaxy. The X-ray emission from the ellipticals is consistent with that expected from a hot interstellar medium, and the spiral galaxy emission may arise from a `super-Eddington' X-ray binary or ultraluminous supernova remnant. Four of the X-ray sources have been detected at radio wavelengths. We also place X-ray upper limits on AGN candidates found in the HDF-N, and we present the t...

  7. AzTEC Millimetre Survey of the COSMOS Field: I. Data Reduction and Source Catalogue

    CERN Document Server

    Scott, K S; Perera, T A; Wilson, G W; Aretxaga, I; Bock, J J; Hughes, D H; Kang, Y; Kim, S; Mauskopf, P D; Sanders, D B; Scoville, N; Yun, M S

    2008-01-01

    We present a 1.1 mm wavelength imaging survey covering 0.3 sq. deg. in the COSMOS field. These data, obtained with the AzTEC continuum camera on the James Clerk Maxwell Telescope (JCMT), were centred on a prominent large-scale structure over-density which includes a rich X-ray cluster at z = 0.73. A total of 50 millimetre galaxy candidates, with a significance ranging from 3.5-8.5 sigma, are extracted from the central 0.15 sq. deg. area which has a uniform sensitivity of 1.3 mJy/beam. Sixteen sources are detected with S/N > 4.5, where the expected false-detection rate is zero, of which a surprisingly large number (9) have intrinsic (de-boosted) fluxes > 5 mJy at 1.1 mm. Assuming the emission is dominated by radiation from dust, heated by a massive population of young, optically-obscured stars, then these bright AzTEC sources have FIR luminosities > 6 x 10^12 L(sun) and star formation-rates > 1100 M(sun)/yr. Two of these nine bright AzTEC sources are found towards the extreme peripheral region of the X-ray clu...

  8. A contrast source method for nonlinear acoustic wave fields in media with spatially inhomogeneous attenuation.

    Science.gov (United States)

    Demi, L; van Dongen, K W A; Verweij, M D

    2011-03-01

    Experimental data reveals that attenuation is an important phenomenon in medical ultrasound. Attenuation is particularly important for medical applications based on nonlinear acoustics, since higher harmonics experience higher attenuation than the fundamental. Here, a method is presented to accurately solve the wave equation for nonlinear acoustic media with spatially inhomogeneous attenuation. Losses are modeled by a spatially dependent compliance relaxation function, which is included in the Westervelt equation. Introduction of absorption in the form of a causal relaxation function automatically results in the appearance of dispersion. The appearance of inhomogeneities implies the presence of a spatially inhomogeneous contrast source in the presented full-wave method leading to inclusion of forward and backward scattering. The contrast source problem is solved iteratively using a Neumann scheme, similar to the iterative nonlinear contrast source (INCS) method. The presented method is directionally independent and capable of dealing with weakly to moderately nonlinear, large scale, three-dimensional wave fields occurring in diagnostic ultrasound. Convergence of the method has been investigated and results for homogeneous, lossy, linear media show full agreement with the exact results. Moreover, the performance of the method is demonstrated through simulations involving steered and unsteered beams in nonlinear media with spatially homogeneous and inhomogeneous attenuation.

  9. Large Subduction Earthquake Simulations using Finite Source Modeling and the Offshore-Onshore Ambient Seismic Field

    Science.gov (United States)

    Viens, L.; Miyake, H.; Koketsu, K.

    2016-12-01

    Large subduction earthquakes have the potential to generate strong long-period ground motions. The ambient seismic field, also called seismic noise, contains information about the elastic response of the Earth between two seismic stations that can be retrieved using seismic interferometry. The DONET1 network, which is composed of 20 offshore stations, has been deployed atop the Nankai subduction zone, Japan, to continuously monitor the seismotectonic activity in this highly seismically active region. The surrounding onshore area is covered by hundreds of seismic stations, which are operated the National Research Institute for Earth Science and Disaster Prevention (NIED) and the Japan Meteorological Agency (JMA), with a spacing of 15-20 km. We retrieve offshore-onshore Green's functions from the ambient seismic field using the deconvolution technique and use them to simulate the long-period ground motions of moderate subduction earthquakes that occurred at shallow depth. We extend the point source method, which is appropriate for moderate events, to finite source modeling to simulate the long-period ground motions of large Mw 7 class earthquake scenarios. The source models are constructed using scaling relations between moderate and large earthquakes to discretize the fault plane of the large hypothetical events into subfaults. Offshore-onshore Green's functions are spatially interpolated over the fault plane to obtain one Green's function for each subfault. The interpolated Green's functions are finally summed up considering different rupture velocities. Results show that this technique can provide additional information about earthquake ground motions that can be used with the existing physics-based simulations to improve seismic hazard assessment.

  10. Infrared-faint radio sources in the SERVS deep fields. Pinpointing AGNs at high redshift

    Science.gov (United States)

    Maini, A.; Prandoni, I.; Norris, R. P.; Spitler, L. R.; Mignano, A.; Lacy, M.; Morganti, R.

    2016-12-01

    Context. Infrared-faint radio sources (IFRS) represent an unexpected class of objects which are relatively bright at radio wavelength, but unusually faint at infrared (IR) and optical wavelengths. A recent and extensive campaign on the radio-brightest IFRSs (S1.4 GHz≳ 10 mJy) has provided evidence that most of them (if not all) contain an active galactic nuclei (AGN). Still uncertain is the nature of the radio-faintest IFRSs (S1.4 GHz≲ 1 mJy). Aims: The scope of this paper is to assess the nature of the radio-faintest IFRSs, testing their classification and improving the knowledge of their IR properties by making use of the most sensitive IR survey available so far: the Spitzer Extragalactic Representative Volume Survey (SERVS). We also explore how the criteria of IFRSs can be fine-tuned to pinpoint radio-loud AGNs at very high redshift (z > 4). Methods: We analysed a number of IFRS samples identified in SERVS fields, including a new sample (21 sources) extracted from the Lockman Hole. 3.6 and 4.5 μm IR counterparts of the 64 sources located in the SERVS fields were searched for and, when detected, their IR properties were studied. Results: We compared the radio/IR properties of the IR-detected IFRSs with those expected for a number of known classes of objects. We found that IR-detected IFRSs are mostly consistent with a mixture of high-redshift (z ≳ 3) radio-loud AGNs. The faintest ones (S1.4 GHz 100 μJy), however, could be also associated with nearer (z 2) dust-enshrouded star-burst galaxies. We also argue that, while IFRSs with radio-to-IR ratios >500 can very efficiently pinpoint radio-loud AGNs at redshift 2 < z < 4, lower radio-to-IR ratios ( 100-200) are expected for higher redshift radio-loud AGNs.

  11. Low pressure water vapour discharge as a light source: II. Electrical characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Artamonova, E; Artamonova, T; Beliaeva, A; Khodorkovskii, M; Melnikov, A; Milenin, V; Murashov, S; Rakcheeva, L; Timofeev, N [Saint Petersburg State University, Ulyanovskaya 3, Petrodvoretz, Saint Petersburg 198504 (Russian Federation); Michael, D [General Electric Global Research Center, One Research Circle (Bldg K1 Rm 4B31A), Niskayuna, NY 12309 (United States); Zissis, G, E-mail: timofeev@pobox.spbu.r, E-mail: michael@crd.ge.co, E-mail: georges.zissis@laplace.univ-tlse.f [Universite Toulouse 3-Paul Sabatier, LAPLACE Building 3R2, 118 rte de Narbonne, F-31062 Toulouse Cedex 9 (France)

    2009-09-07

    The electric field strength, electrode fall voltage, light emission characteristics and efficiency of a (Ar + H{sub 2}O) dc discharge as functions of water vapour content, argon pressure and electric current are presented. The data show that the main processes of 306.4 nm OH band generation are (1) a collision between an excited argon atom and a water molecule with simultaneous excitation of OH into the A {sup 2}{Sigma}{sup +} state and (2) electron excitation of a ground state hydroxyl molecule produced by a quenching process from a water molecule. Electric field strength measurements make it possible to conclude that the light production efficiency of the plasma under study can reach 35 lm W{sup -1}. It is possible, with these data, to propose a model of the plasma in question having reasonable accordance with the experiment and show the way to further increase the efficiency.

  12. On the physics of power, energy and economics of renewable electric energy sources - Part II

    Energy Technology Data Exchange (ETDEWEB)

    Skoglund, Annika [Dep. of Industrial Economics, Royal Institute of Technology, Lindstedts vaeg 30, 100 44 Stockholm (Sweden); Leijon, Mats; Waters, Rafael [Div. of Electricity, Swedish Centre for Renewable Electric Energy Conversion, Uppsala University, Aangstroem 751 21 Uppsala (Sweden); Rehn, Alf [Dep. of Business Administration, Aabo Akademi University, Henriksgatan 7FIN-20500 Aabo (Finland); Lindahl, Marcus [Div. of Industrial Management, Uppsala University, Aangstroem 751 21 Uppsala (Sweden)

    2010-08-15

    Renewable Energy Technologies (RETs) are often recognized as less competitive than traditional electric energy conversion systems. Obstacles with renewable electric energy conversion systems are often referred to the intermittency of the energy sources and the relatively high maintenance cost. However, due to an intensified discourse on climate change and its effects, it has from a societal point of view, become more desirable to adopt and install CO{sub 2} neutral power plants. Even if this has increased the competitiveness of RETs in a political sense, the new goals for RET installations must also be met with economical viability. We propose that the direction of technical development, as well as the chosen technology in new installations, should not primarily be determined by policies, but by the basic physical properties of the energy source and the associated potential for inexpensive energy production. This potential is the basic entity that drives the payback of the investment of a specific RET power plant. With regard to this, we argue that the total electric energy conversion system must be considered if effective power production is to be achieved, with focus on the possible number of full loading hours and the Degree of Utilization. This will increase the cost efficiency and economical competitiveness of RET investments, and could enhance faster diffusion of new innovations and installations without over-optimistic subsidies. This paper elaborates on the overall problem of the economy of renewable electric energy conversion systems by studying the interface between physics, engineering and economy reported for RET power plants in different scientific publications. The core objective is to show the practical use of the Degree of Utilization and how the concept is crucial for the design and economical optimization disregarding subsidies. The results clearly indicate that the future political regulative frameworks should consider the choice of renewable

  13. Long-term studies with the Ariel 5 ASM. II - The strong Cygnus sources

    Science.gov (United States)

    Holt, S. S.; Kaluzienski, L. J.; Boldt, E. A.; Serlemitsos, P. J.

    1979-01-01

    The three bright 3-6 keV X-ray sources in Cygnus are examined for regular temporal variability with a 1300 day record from the Ariel 5 All-Sky Monitor. The only periods consistently observed are 5.6 days for Cyg X-1, 11.23 days for Cyg X-2, and 4.8 hours for Cyg X-3. The 78.4 day period of Kemp, Herman, and Barbour for Cyg X-1, the 9.843 day period of Cowley, Crampton, and Hutchings for Cyg X-2, and the 16.75 day period of Holt et al. for Cyg X-3 are not confirmed.

  14. Symbiotic Stars in X-rays. II. Faint Sources Detected with XMM-Newton and Chandra

    Science.gov (United States)

    Nunez, N. E.; Luna, G. J. M.; Pillitteri, I.; Mukai, K.

    2014-01-01

    We report the detection from four symbiotic stars that were not known to be X-ray sources. These four object show a ß-type X-ray spectrum, that is, their spectra can be modeled with an absorbed optically thin thermal emission with temperatures of a few million degrees. Photometric series obtained with the Optical Monitor on board XMM-Newton from V2416 Sgr and NSV 25735 support the proposed scenario where the X-ray emission is produced in a shock-heated region inside the symbiotic nebulae.

  15. A calderón-preconditioned single source combined field integral equation for analyzing scattering from homogeneous penetrable objects

    KAUST Repository

    Valdés, Felipe

    2011-06-01

    A new regularized single source equation for analyzing scattering from homogeneous penetrable objects is presented. The proposed equation is a linear combination of a Calderón-preconditioned single source electric field integral equation and a single source magnetic field integral equation. The equation is immune to low-frequency and dense-mesh breakdown, and free from spurious resonances. Unlike dual source formulations, this equation involves operator products that cannot be discretized using standard procedures for discretizing standalone electric, magnetic, and combined field operators. Instead, the single source equation proposed here is discretized using a recently developed technique that achieves a well-conditioned mapping from div- to curl-conforming function spaces, thereby fully respecting the space mapping properties of the operators involved, and guaranteeing accuracy and stability. Numerical results show that the proposed equation and discretization technique give rise to rapidly convergent solutions. They also validate the equation\\'s resonant free character. © 2006 IEEE.

  16. Neutral Beam Source and Target Plasma for Development of a Local Electric Field Fluctuation Diagnostic

    Science.gov (United States)

    Bakken, M. R.; Burke, M. G.; Fonck, R. J.; Lewicki, B. T.; Rhodes, A. T.; Winz, G. R.

    2016-10-01

    A new diagnostic measuring local E-> (r , t) fluctuations is being developed for plasma turbulence studies in tokamaks. This is accomplished by measuring fluctuations in the separation of the π components in the Hα motional Stark spectrum. Fluctuations in this separation are expected to be Ẽ / ẼEMSE 10-3EMSE 10-3 . In addition to a high throughput, high speed spectrometer, the project requires a low divergence (Ω 0 .5°) , 80 keV, 2.5 A H0 beam and a target plasma test stand. The beam employs a washer-stack arc ion source to achieve a high species fraction at full energy. Laboratory tests of the ion source demonstrate repeatable plasmas with Te 10 eV and ne 1.6 ×1017 m-3, sufficient for the beam ion optics requirements. Te and ne scalings of the ion source plasma are presented with respect to operational parameters. A novel three-phase resonant converter power supply will provide 6 mA/cm2 of 80 keV H0 at the focal plane for pulse lengths up to 15 ms, with low ripple δV / 80 keV 0.05 % at 280 kHz. Diagnostic development and validation tests will be performed on a magnetized plasma test stand with 0.5 T field. The test chamber will utilize a washer-stack arc source to produce a target plasma comparable to edge tokamak plasmas. A bias-plate with programmable power supply will be used to impose Ẽ within the target plasma. Work supported by US DOE Grant DE-FG02-89ER53296.

  17. On the problems of stability and durability of field-emission current sources for electrovacuum devices

    Science.gov (United States)

    Yakunin, Alexander N.; Aban'shin, Nikolay P.; Akchurin, Garif G.; Akchurin, Georgy G.; Avetisyan, Yuri A.

    2016-03-01

    The results of the practical implementation of the concept of field-emission current source with high average current density of 0.1-0.3 A-cm-2 are shown. The durability of cathode samples at a level of 6000 hours is achieved under conditions of technical vacuum. A phenomenological model is suggested that describes the tunneling of both equilibrium and nonequilibrium electrons in a vacuum from the zone of concentration of electrostatic field. Conditions are discussed as the resulting increase in the emission current due to the connection mechanism of the photoelectric effect is thermodynamically favorable, that is not accompanied by an undesirable increase in the temperature of the local emission zone. It is shown that to ensure stability and durability of the cathode is also important to limit the concentration of equilibrium carriers using composite structures «DLC film on Mo substrate." This helps to reduce the criticality of the CVC. A possible alternative is to use a restrictive resistance in the cathode. However, this increases the heat losses and thus decreases assembly efficiency. The results of experimental studies of the structure showing the saturation of photoemission current component with an increase in operating voltage. This fact suggests the existence of an effective mechanism for control of emission at constant operating voltage. This is fundamentally important for the stabilization of field emission cathode, providing a reliability and durability. The single-photon processes and the small thickness DLC films (15-20 nm) provide high-speed process of control.

  18. Field Investigation of an Air-Source Cold Climate Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [ORNL; Abdelaziz, Omar [ORNL; Rice, C Keith [ORNL; Baxter, Van D [ORNL

    2017-01-01

    In the U.S., there are approximately 2.6 million dwellings that use electricity for heating in cold and very cold regions with an annual energy consumption of 0.16 quads (0.17 EJ). A high performance cold climate heat pump (CCHP) would result in significant savings over current technologies (greater than 60% compared to electric resistance heating). We developed an air-source cold climate heat pump, which uses tandem compressors, with a single compressor rated for the building design cooling load, and running two compressors to provide, at -13 F (-25 C), 75% of rated heating capacity. The tandem compressors were optimized for heating operation and are able to tolerate discharge temperatures up to 280 F (138 C). A field investigation was conducted in the winter of 2015, in an occupied home in Ohio, USA. During the heating season, the seasonal COP was measured at 3.16, and the heat pump was able to operate down to -13 F (-25 C) and eliminate resistance heat use. The heat pump maintained an acceptable comfort level throughout the heating season. In comparison to a previous single-speed heat pump in the home, the CCHP demonstrated more than 40% energy savings in the peak heating load month. This paper illustrates the measured field performance, including compressor run time, frost/defrosting operations, distributions of building heating load and capacity delivery, comfort level, field measured COPs, etc.

  19. Separation of image-distortion sources and magnetic-field measurement in scanning electron microscope (SEM).

    Science.gov (United States)

    Płuska, Mariusz; Czerwinski, Andrzej; Ratajczak, Jacek; Katcki, Jerzy; Oskwarek, Lukasz; Rak, Remigiusz

    2009-01-01

    The electron-microscope image distortion generated by electromagnetic interference (EMI) is an important problem for accurate imaging in scanning electron microscopy (SEM). Available commercial solutions to this problem utilize sophisticated hardware for EMI detection and compensation. Their efficiency depends on the complexity of distortions influence on SEM system. Selection of a proper method for reduction of the distortions is crucial. The current investigations allowed for a separation of the distortions impact on several components of SEM system. A sum of signals from distortion sources causes wavy deformations of specimen shapes in SEM images. The separation of various reasons of the distortion is based on measurements of the periodic deformations of the images for different electron beam energies and working distances between the microscope final aperture and the specimen. Using the SEM images, a direct influence of alternating magnetic field on the electron beam was distinguished. Distortions of electric signals in the scanning block of SEM were also separated. The presented method separates the direct magnetic field influence on the electron beam below the SEM final aperture (in the chamber) from its influence above this aperture (in the electron column). It also allows for the measurement of magnetic field present inside the SEM chamber. The current investigations gave practical guidelines for selecting the most efficient solution for reduction of the distortions.

  20. FOUR PI CALIBRATION AND MODELING OF A BARE GERMANIUM DETECTOR IN A CYLINDRICAL FIELD SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Dewberry, R.; Young, J.

    2011-04-29

    In reference 1 the authors described {gamma}-ray holdup assay of a Mossbauer spectroscopy instrument where they utilized two axial symmetric cylindrical shell acquisitions and two disk source acquisitions to determine Am-241 and Np-237 contamination. The measured contents of the two species were determined using a general detector efficiency calibration taken from a 12-inch point source.2 The authors corrected the raw spectra for container absorption as well as for geometry corrections to transform the calibration curve to the applicable axial symmetric cylindrical source - and disk source - of contamination. The authors derived the geometry corrections with exact calculus that are shown in equations (1) and (2) of our Experimental section. A cylindrical shell (oven source) acquisition configuration is described in reference 3, where the authors disclosed this configuration to gain improved sensitivity for holdup measure of U-235 in a ten-chamber oven. The oven was a piece of process equipment used in the Savannah River Plant M-Area Uranium Fuel Fabrication plant for which a U-235 holdup measurement was necessary for its decontamination and decommissioning in 2003.4 In reference 4 the authors calibrated a bare NaI detector for these U-235 holdup measurements. In references 5 and 6 the authors calibrated a bare HpGe detector in a cylindrical shell configuration for improved sensitivity measurements of U-235 in other M-Area process equipment. Sensitivity was vastly improved compared to a close field view of the sample, with detection efficiency of greater than 1% for the 185.7-keV {gamma}-ray from U-235. In none of references 3 - 7 did the authors resolve the exact calculus descriptions of the acquisition configurations. Only the empirical efficiency for detection of the 185.7-keV photon from U-235 decay was obtained. Not until the 2010 paper of reference 1 did the authors derive a good theoretical description of the flux of photons onto the front face of a detector