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Flash-Type Discrimination

By: Koshak, William J

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; This viewgraph presentation describes the significant progress made in the flash-type discrimination algorithm development. The contents inc...

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Positive Ionospheric Storm Effects at Latin America Longitude During the Superstorm of 20–22 November 2003: Revisit : Volume 30, Issue 5 (10/05/2012)

By: J. Lei; Y. Wei; B. Reinisch; B. Zhao; Y. Sahai; W. Wan

Description: Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China. Positive ionospheric storm effects that occurred during the superstorm on 20 November 2003 are investigated using a combination of ground-based Global Positioning System (GPS) total electron content (TEC), and the meridian chain of ionosondes distributed along the Latin America longitude of ~280° E. Both the ground-based GPS TEC and ionosonde electron density profile data reveal significant enhancements at mid-low latitudes over the 280° E region during the main phase of the November 2003 superstorm. The maximum enhancement of the topside ionospheric electron content is 3.2–7.7 times of the bottomside ionosphere at the locations of the ionosondes distributed around the mid- and low latitudes. Moreover, the height of maximum electron density exceeds 400 km and increases by 100 km compared with the quiet day over the South American area from middle to low latitudes, which might have resulted from a continuous eastward penetration electric field and storm-generated equatorward wi...

Abdu, M. A., Batista, I. S., Carrasco, A. J., and Brum, C. G. M.: South Atlantic magnetic anomaly, ionization: A review and a new focus on electrodynamic effects in the equatorial ionosphere, J. Atmos. Solar Terr.Phys., 67, 1643–1657, 2005.; Anderson, D., Anghel, A., Yumoto, K., Ishitsuka, M., and Kudeki, E.: Estimating daytime vertical $\vec{E}\times\vec{B}$ drift velocities in the equatorial F region using ground-based magnetometer observations, Geophys. Res. Lett., 29, 1596, doi:10.1029/2001GL014562, 2002.; Anderson, D., Anghel, A., Araujo, E., Eccles, V., Valladares, C., and Lin, C.: Theoretically modeling the lowlatitude, ionospheric response to large geomagnetic storms, Radio Sci., 41, RS5S04, doi:10.1029/2005RS003376, 2006.; Araki, T.: A physical model of the geomagnetic sudden commencement, Geophys. Monogr., 81, 183–200, 1994.; Astafyeva, E.: Effects of strong IMF $B_z$ southward events on the equatorial and mid-latitude ionosphere, Ann. Geophys., 27, 1175–1187, doi:10.519...

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Marquette Island: A Distinct Mafic Lithology Discovered by Opportunity

By: Mittlefehldt, David W. ; Gellert, R. ; Herkenhoff, K. E. ; Clark, B. C. ; Cohen, B. A. ; Fleischer, I. ; Jolliff, B. L. ; Klingelhoefer, G. ; Ming, D. W. ; Yingst, R. A

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; While rolling over the Meridiani Planum sedimentary terrane, the rover Opportunity has occasionally discovered large, 10 cm erratics. Most o...

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Rocket and Radar Investigation of Background Electrodynamics and Bottom-type Scattering Layers at the Onset of Equatorial Spread F : Volume 24, Issue 5 (03/07/2006)

By: T. W. Bullett; A. Barjatya; C. M. Swenson; T. F. Wheeler; D. L. Hysell; M. F. Larsen; J. L. Chau; D. Sponseller; M. F. Sarango; R. F. Woodman

Description: Earth and Atmospheric Science, Cornell University, Ithaca, New York, USA. Sounding rocket experiments were conducted during the NASA EQUIS II campaign on Kwajalein Atoll designed to elucidate the electrodynamics and layer structure of the postsunset equatorial F region ionosphere prior to the onset of equatorial spread F (ESF). Experiments took place on 7 and 15 August 2004, each comprised of the launch of an instrumented and two chemical release sounding rockets. The instrumented rockets measured plasma number density, vector electric fields, and other parameters to an apogee of about 450 km. The chemical release rockets deployed trails of trimethyl aluminum (TMA) which yielded wind profile measurements. The Altair radar was used to monitor coherent and incoherent scatter in UHF and VHF bands. Electron density profiles were also measured with rocket beacons and an ionosonde. Strong plasma shear flow was evident in both experiments. Bottom-type scattering layers were observed mainly in the valley region, below the shear nodes, in westward-drifting plasma strata. The layers were likely pr...

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Aerial navigation : on the problem of guiding aircraft in a fog or by night when there is no visibility

By: Loth, Willia

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; The use of magnetic fields and wire to navigate aircraft in conditions of poor visibility is presented. This field may be considered to be d...

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The Field Radiated from Two Horizontal Coils; Aeroplane Landings Aided By Wireless Signals

Description: The landing of aeroplanes can be facilitated by emitting from the landing field a vertical beam of radio-frequency electromagnetic radiation. A type of transmitting coil antenna has been devised for this purpose by J.A. Willoughby, of the Bureau of Standards. The behaviour of this transmitting coil antenna is calculated in the paper. Formulæ are worked out for the current received in a coil aerial and in an antenna oriented in a known manner at a sufficient distance from the transmitter. It is found that if a vertical coil aerial is used for reception and if the aeroplane flies horizontally a maximum signal is obtained when the distance l makes an angle of 30° with the vertical. The influence of the earth is also...

Digitized by NIST Research Library

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MoCog1: A computer simulation of recognition-primed human decision making

By: Gevarter, William B

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; The results of the first stage of a research effort to develop a 'sophisticated' computer model of human cognitive behavior are described. M...

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Radial Evolution of Intermittent Heat Flux in Solar Coronal Holes : Volume 11, Issue 4 (08/11/2004)

By: J. V. Hollweg; S. A. Markovskii

Description: Space Science Center, University of New Hampshire, Durham, NH 03824, USA. Recently, we suggested that the source of ion heating in solar coronal holes is small-scale reconnection events (microflares) at the coronal base. The microflares launch intermittent heat flux up into the corona exciting ion cyclotron waves through a plasma microinstability. The ions are heated by these waves during the microflare bursts and then evolve with no energy input between the bursts. The overall coronal heating by this mechanism is a summed effect of all microflare bursts during the expansion time of the solar wind and adiabatic cooling between the microflares. The intermittent heat flux produced by the microflares was modeled as electron beams with constant speed and temperature for simplicity. In this paper, we consider a more sophisticated model of the heat flux taking into account the action of the mirror force and the charge separation electric field on the beam particles. We show that the radial evolution of the heat flux is determined mainly by the beam expansion along the magnetic field roughly at the root mean squar...

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NASA Automated Rendezvous and Capture Review. A compilation of the abstracts

By: NON

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; This document presents a compilation of abstracts of papers solicited for presentation at the NASA Automated Rendezvous and Capture Review h...

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Observations of Pc5 Micropulsation-related Electric Field Oscillations in the Equatorial Ionosphere : Volume 12, Issue 6 (30/11/-0001)

By: K. S. Viswanathan; T. Araki; C. A. Reddy; D. R. K. Rao; B. V. Krishna Murthy; Sudha Ravindran

Description: A 54.95-MHz coherent backscatter radar, an ionosonde and the magnetometer located at Trivandrum in India (8.5°N, 77°E, 0.5°N dip angle) recorded large-amplitude ionospheric fluctuations and magnetic field fluctuations associated with a Pc5 micropulsation event, which occurred during an intense magnetic storm on 24 March 1991 (Ap=161). Simultaneous 100-nT-level fluctuations are also observed in the H-component at Brorfelde, Denmark (55.6°N gm) and at Narsarsuaq, Greenland (70.6°N gm). Our study of the above observations shows that the E-W electric field fluctuations in the E- and F-regions and the magnetic field fluctuations at Thumba are dominated by a near-sinusoidal oscillation of 10 min during 1730-1900 IST (1200-1330 UT), the amplitude of the electric field oscillation in the equatorial electrojet (EEJ) is 0.1-0.25 mV m-1 and it increases with height, while it is about 1.0 mV m-1 in the F-region, the ground-level H-component oscillation can be accounted for by the ionospheric current oscillation generated by the observed electric field oscillation in the EEJ and the H-...

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Acoustic mode measurements in the inlet of a model turbofan using a continuously rotating rake

By: Heidelberg, Laurence J. ; Hall, David G

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; Comprehensive measurements of the spinning acoustic mode structure in the inlet of the Advanced Ducted Propeller (ADP) have been completed....

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Response of Ionospheric Electric Fields to Variations in the Interplanetary Magnetic Field : Volume 14, Issue 8 (30/11/-0001)

By: E. Nielsen; S. P. Mishra

Description: The STARE system (Scandinavian Twin Auroral Radar Experiment) provides estimates of electron drift velocities, and hence also of the electric field in the high-latitude E-region ionosphere between 65 and 70 degrees latitude. The occurrence of drift velocities larger than about 400 m/s (equivalent to an electric field of 20 mV/m) have been correlated with the magnitude of the Interplanetary Magnetic Field (IMF) components Bz and By at all local times. Observation days have been considered during which both southward (Bz<0) and northward (Bz>0) IMF occurred. The occurrence of electric fields larger than 20 mV/m increases with increases in Bz magnitudes when Bz<0. It is found that the effects of southward IMF continue for some time following the northward turnings of the IMF. In order to eliminate such residual effects for Bz<0, we have, in the second part of the study, considered those days which were characterized by a pure northward IMF. The occurrence is considerably lower during t...

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Determination of parameters of a new method for predicting alloy properties

By: Bozzolo, Guillermo; Ferrante, Joh

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; Recently, a semiempirical method for alloys based on equivalent crystal theory was introduced. The method successfully predicts the concentr...

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Experimental Evidence of the Simultaneous Occurrence of Vlf Chorus on the Ground in the Global Azimuthal Scale – from Pre-midnight to the Late Morning : Volume 30, Issue 4 (24/04/2012)

By: M. Parrot; T. Turunen; O. V. Kozyreva; N. G. Kleimenova; T. Raita; J. Manninen

Description: Sodankylä Geophysical Observatory, Finland. Night-time VLF (very low frequency) chorus bursts lasting about one hour have been recorded at Finnish temporal station Kannuslehto (CGM: 64.2°; 107.9°, L = 5.3) during two VLF campaigns (on 25 February–4 March 2008 and 27 March–17 April 2011). The chorus bursts were associated with substorm development. They were accompanied by riometer absorption enhancements, which occurred simultaneously within as large longitude areas as from pre-midnight (Sodankylä, ~22:00 MLT) to the late morning (Tixie, ~03:00 MLT and Gakona, ~08:00 MLT) longitudes. It was found that the pre-midnight chorus observed on the ground occurred simultaneously with VLF chorus emissions recorded in the late morning on the low-altitude DEMETER satellite crossing the similar geomagnetic latitudes on the opposite local time sector. For the first time some evidence of simultaneous chorus burst generation in the global longitudinal scale was found (from pre-midnight to the late morning) by using direct comparison with satellite data as well as using non-direct indicator–azimuthally extended rio...

Agapitov, O., Krasnoselskikh, V., Zaliznyak, Yu., Angelopoulos, V., Le Contel, O., and Rolland, G.: Chorus source region localization in the Earth's outer magnetosphere using THEMIS measurements, Ann. Geophys., 28, 1377–1386, doi:10.5194/angeo-28-1377-2010, 2010.; Anderson, R. R. and Maeda, K.: VLF emissions associated with enhanced magnetospheric electrons, J. Geophys. Res., 82, 135–146, 1977.; Bortnik, J. and Thorne, R. M.: The dual role of ELF/VLF chorus waves in the acceleration and precipitation of radiation belt electrons, J. Atmos. Sol. Terr. Phys., 69, 377–386, 2007.; Bortnik, J., Thorne, R. M., and Inan, U. S.: Nonlinear interaction of energetic electrons with large amplitude chorus, Geophys. Res. Lett., 35, L21102, doi:10.1029/2008GL035500, 2008.; Collier, A. B. and Hughes, A. R. W.: Modelling substorm chorus events in terms of dispersive azimuthal drift, Ann. Geophys., 22, 4311–4327, doi:10.5194/angeo-22-4311-2004, 2004.; Gołkowski, M. and Inan, U. S.: Multist...

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Analysis of SMS-2 attitude sensor behavior including OABIAS results

By: Chen, L. C

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; The Synchronous Meteorological Satellite-2 (SMS-2) was launched on 6 Feb. 1975. For the first four days of the mission an extensive program...

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A Multi-spacecraft Survey of Magnetic Field Line Draping in the Dayside Magnetosheath : Volume 23, Issue 3 (30/03/2005)

By: I. J. Coleman

Description: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK. When the interplanetary magnetic field (IMF) encounters the Earth's magnetosphere, it is compressed and distorted. This distortion is known as draping, and plays an important role in the interaction between the IMF and the geomagnetic field. This paper considers a particular aspect of draping, namely how the orientation of the IMF in a plane perpendicular to the Sun-Earth line (the clock angle) is altered by draping in the magnetosheath close to the dayside magnetopause. The clock angle of the magnetosheath field is commonly estimated from the interplanetary magnetic field (IMF) measured by upstream monitoring spacecraft either by assuming that the draping process does not significantly alter the clock angle (perfect draping) or that the change in clock angle is reasonably approximated by a gas dynamic model. In this paper, the magnetosheath clock angles measured during 36 crossings of the magnetopause by the Geotail and Interball-Tail spacecraft are compared to the upstream IMF clock angles measured by the Wind spacecraft. Overal...

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Control and augmentation of passive porosity through transpiration control

By: NON

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; A device for controlling pressure loading of a member caused by a fluid moving past the member or the member moving through a fluid is prese...

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Considerations on the Frequency Resource of Professional Wireless Microphone Systems : Volume 6, Issue 1 (26/05/2008)

By: I. Rolfes; M. Fehr; S. Dortmund

Description: Institute for Radiofrequency and Microwave Engineering, Leibniz Universität Hannover, Germany. This Paper presents the results of spectral observations in the UHF TV Bands IV and V from 470 MHz up to 862 MHz with focus on the TV-Channels 61 to 63 and 67 to 69. Concerning the discussions on \citet{WRC} this frequency range is in great demand of several applications and is usually treated as a white space in the TV-Bands. According to typical scenarios, two different spectral loads will be presented considering the requirements of professional wireless microphone receivers with respect to in-band intermodulation....

BNetzA: Allgemeinzuteilung von Frequenzen für drahtlose Mikrofone für professionelle Nutzung in den Frequenzbereichen 790–814 und 838–862 MHz, Bonn, Germany, 2005 (http://www.bundesnetzagentur.de/media/archive/4469.pdf).; CEPT: The Chester 1997 multilateral coordination agreement related to technical criteria, coordination principles and procedures for the introduction of Terrestrial Digial Video Broadcasting (DVB-T), Chester, England, 1997 (http://www.ero.dk/132D67A4-8815-48CB-B482-903844887DE3?frames=0).; ERC: Compatibility and sharing analysis between DVB-T and radio microphones in bands IV and V, Naples, Italy, 2000 (http://www.ero.dk/doc98/official/Word/REP088.DOC).; ETSI: Electromagnetic compatibility and Radio Spectrum Matters (ERM), Technical characteristics for Professional Wireless Microphone Systems (PWMS), System Reference Document, Sophia-Antipolis, France, 2006.; Konstantinos, M., Athanassios, A. V.,Petros, V. P., Elias, K. K., Nocolaos, R. E., and Constantinou, P.: A new methology for frequency coordination of wireless microphone systems over occupied TV-spectrum, IEEE Conference on wireless and mobile computing, netw...

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Application of three-dimensional Bezier patches in grid generation

By: Mastin, C. Wayn

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; Bezier and B-spline patches are popular tools in surface modeling. With these methods, a surface is represented by the tensor product of uni...

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Non-linear Dynamo Waves in an Incompressible Medium when the Turbulence Dissipative Coefficients Depend on Temperature : Volume 15, Issue 1 (30/11/-0001)

By: T. A. Pataraya; A. D. Pataraya

Description: Abastumany Astrophysical Observatory, Kazbegi Str. 2, 380060, Tbilisi, Republic of Georgia. Non-linear α-ω; dynamo waves existing in an incompressible medium with the turbulence dissipative coefficients depending on temperature are studied in this paper. We investigate of α-ω solar non-linear dynamo waves when only the first harmonics of magnetic induction components are included. If we ignore the second harmonics in the non-linear equation, the turbulent magnetic diffusion coefficient increases together with the temperature, the coefficient of turbulent viscosity decreases, and for an interval of time the value of dynamo number is greater than 1. In these conditions a stationary solution of the non-linear equation for the dynamo wave's amplitude exists; meaning that the magnetic field is sufficiently excited. The amplitude of the dynamo waves oscillates and becomes stationary. Using these results we can explain the existence of Maunder's minimum....

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The NASA Scientific and Technical Information Program: Prologue to the future

By: NON

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; The NASA STI Program offers researchers an infrastructure of people and systems that facilitates access to STI; worldwide. The Program is al...

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Investigation of the Behaviour of Uwb Protection Elements Against Hpm Signals : Volume 6, Issue 11 (26/05/2008)

By: R. Krzikalla; J. L. Ter Haseborg; F. Brauer

Description: Institute of Measurement Technology and EMC, Hamburg, Germany. The development of protection circuits against a variety of electromagnetic disturbances is important to assure the immunity to interferences of an electronic system. In this paper protection elements which were investigated under UWB conditions are now to be tested with HPM signals to achieve a comprehensive protection....

Weber, T., Krzikalla R., and ter Haseborg, J. L.: Linear and Nonlinear Filters Suppressing UWB Pulses, IEEE Transactions on EMC, Vol. 46, No. 3, August, 2004.; Krzikalla, R., Weber, T., and ter Haseborg, J. L.: EMP und UWB Schutz von elektronischen Bauelementen – Final report of the BWB-contract E/E590/1X038/Y5140, October, 2004.; Weber, T.: Messverfahren und Schutzmaßnahmen für elektromagnetische Pulse im UWB-Bereich, PhD Thesis, Hamburg University of Technology, 2004.; Borgeest, K.: Optimierung und Simulation des transienten Ansprech- und Übertragungsverhaltens nichtlinearer Schutzschaltungen für HF-Systeme, PhD Thesis, Hamburg University of Technology, 1998....

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How to securely replicate services (preliminary version)

By: Reiter, Michael; Birman, Kennet

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; A method is presented for constructing replicated services that retain their availability and integrity despite several servers and clients...

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Plos One : Probing the Neural Basis of Perceptual Phenomenology with the Touch-induced Visual Illusion, Volume 7

By: Maurice Ptito

Description : Using the touch-induced visual illusion we examine whether the brain regions involved in coding sensory information are dissociable from those that contain decision information. Activity in the intraparietal sulcus, as measured by functional magnetic resonance imaging, was associated with the illusion suggesting a sensory coding role whereas activity in the middle occipital gyrus differentially modulated activity according to the decisions made by subjects consistent with their reported perceptual phenomenology....

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Magnetic effects of large-scale impacts on airless planetary bodies

By: Hood, L. L. ; Huang, Z

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; The analysis of lunar orbital and sample data combined with laboratory measurements of impact-produced plasmas suggest that large-scale impa...

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Experimental Test of the Ρ(1-α) Evolution for Rotational Discontinuities: Cluster Magnetopause Observations : Volume 33, Issue 1 (15/01/2015)

By: B. Klecker; O. Marghitu; G. Paschmann; A. Blagau

Description: Institute for Space Sciences, Bucharest, Romania. Rotational discontinuities (RDs) are governed by two relations: the Walén relation predicting that the plasma velocity observed in the deHoffmann–Teller frame equals the local Alfvén velocity and another relation that connects the variation in plasma mass density, Ρ, to variations in the pressure anisotropy factor, α, defined as Α: ≡(pp) Μ0/B2, so that Ρ(1 − Α) is constant. While the Walén relation has become a standard tool for classifying magnetopause crossings as RDs , the Ρ(1 − Α)= const. condition has never been directly verified at the same time, largely due to problems with determining Ρ when no ion composition measurements were available. In fact, to overcome the lack of composition information, the validity of the relation has often been assumed and the Walén relation reformulated so that variations in Ρ are replaced by variations in α. In this paper we exploit the availability of high-time-resolution composition measurements on the Cluster spacecraft to directly test the...

Balogh, A., Carr, C. M., Acuña, M. H., Dunlop, M. W., Beek, T. J., Brown, P., Fornacon, K.-H., Georgescu, E., Glassmeier, K.-H., Harris, J., Musmann, G., Oddy, T., and Schwingenschuh, K.: The Cluster Magnetic Field Investigation: overview of in-flight performance and initial results, Ann. Geophys., 19, 1207–1217, doi:10.5194/angeo-19-1207-2001, 2001.; Bauer, T. M.: Particles and Fields at the Dayside Low-latitude Magnetopause, Ph.D. thesis, Max-Planck-Institut für extraterrestrische Physik, Garching, Germany, 1997.; Blagau, A.: Characteristics of Earth's magnetopause from Cluster measurements, Ph.D. thesis, Max-Planck-Institut für extraterrestrische Physik, Garching, Germany, available at: http://edoc.ub.uni-muenchen.de/7806/ (last access: 12 January 2015), 2007.; Borovsky, J. E., Denton, M. H., Denton, R. E., Jordanova, V. K., and Krall, J.: Estimating the effects of ionospheric plasma on solar wind/magnetosphere coupling via mass loading of dayside reconnection: Ion-plasma-sheet oxygen, plasmaspheric drainage plumes, and the p...

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M.S.L.A.P. Modular Spectral Line Analysis Program documentation

By: Joseph, Charles L. ; Jenkins, Edward B

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; MSLAP is a software for analyzing spectra, providing the basic structure to identify spectral features, to make quantitative measurements of...

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Severe Geomagnetic Storms and Forbush Decreases: Interplanetary Relationships Reexamined : Volume 28, Issue 2 (09/02/2010)

By: R. P. Kane

Description: Instituto Nacional de Pesquisas Espaciais, C.P. 515, 12245-970 – São José dos Campos, SP, Brazil. Severe storms (Dst) and Forbush decreases (FD) during cycle 23 showed that maximum negative Dst magnitudes usually occurred almost simultaneously with the maximum negative values of the Bz component of interplanetary magnetic field B, but the maximum magnitudes of negative Dst and Bz were poorly correlated (+0.28). A parameter Bz(CP) was calculated (cumulative partial Bz) as sum of the hourly negative values of Bz from the time of start to the maximum negative value. The correlation of negative Dst maximum with Bz(CP) was higher (+0.59) as compared to that of Dst with Bz alone (+0.28). When the product of Bz with the solar wind speed V (at the hour of negative Bz maximum) was considered, the correlation of negative Dst maximum with VBz was +0.59 and with VBz(CP), 0.71. Thus, including V improved the corre...

Barnden, L. R.: The Large-Scale Magnetic Field Configuration Associated With Forbush Decreases, Proc. 13th Int. Cosmic Ray Conf., 2, 1277, 1973.; Belov, A. V. and Ivanov, K. G.: Forbush-Effects in 1977–1979, Proc. 25th Int. Cosmic Ray Conf., Durban, 1, 421, 1997.; Belov, A. V., Eroshenko, E. A., Oleneva, V. A., Struminsky, A. B., and Yanke, V. G.: What determines the magnitude of Forbush decreases?, Adv. Space Res., 27(3), 625–630, 2001.; Belov, A., Baisultanova, L., Eroshenko, E., Mavromichalaki, H., Yanke, V., Pchelkin, V., Plainaki, C., and Mariatos, G.: Magnetospheric effects in cosmic rays during the unique magnetic storm on November 2003, J. Geophys. Res., 110, A09S20, doi:10.1029/2005JA011067, 2005.; Burlaga, L. F., McDonald, F. B., Ness, N. F., Schwenn, R., Lazarus, A. J., and Mariani, F.: Interplanetary flow systems associated with cosmic ray modulation in 1977–1980, J. Geophys. Res., 89, 6579–6587, 1984.; Cane, H. V.: Cosmic Ray Decreases and Magnetic Clouds, J. Geophys. Res., 98, 3509–3512, 1993.; Cane, H. V.: Coronal mass ejections and Forbush decreases, Space Sci. Rev., 93, 55–77, 2000.; Cane, H. V., Richardson, I. G., ...

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CFD analysis of jet mixing in low NOx flametube combustors

By: Talpallikar, M. V. ; Lai, M. C. ; Holdeman, J. D; Smith, C. E.

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; The Rich-burn/Quick-mix/Lean-burn (RQL) combustor was identified as a potential gas turbine combustor concept to reduce NO(x) emissions in H...

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Weak Ionization of the Global Ionosphere in Solar Cycle 24 : Volume 32, Issue 7 (21/07/2014)

By: D. H. Zhang; Z. Xiao; H. Shi; Y. Q. Hao

Description: Department of Geophysics, Peking University, Beijing, China. Following prolonged and extremely quiet solar activity from 2008 to 2009, the 24th solar cycle started slowly. It has been almost 5 years since then. The measurement of ionospheric critical frequency (foF2) shows the fact that solar activity has been significantly lower in the first half of cycle 24, compared to the average levels of cycles 19 to 23; the data of global average total electron content (TEC) confirm that the global ionosphere around the cycle 24 peak is much more weakly ionized, in contrast to cycle 23. The weak ionization has been more notable since the year 2012, when both the ionosphere and solar activity were expected to be approaching their maximum level. The undersupply of solar extreme ultraviolet (EUV) irradiance somewhat continues after the 2008–2009 minimum, and is considered to be the main cause of the weak ionization. It further implies that the thermosphere and ionosphere in the first solar cycle of this millennium would probably differ from what we have ...

Araujo-Pradere, E. A., Redmon, R., Fedrizzi, M., Viereck, R., and Fuller-Rowell, T. J.: Some Characteristics of the Ionospheric Behavior During the Solar Cycle 23–24 Minimum, Sol. Phys., 274, 439–456, doi:10.1007/s11207-011-9728-3, 2011.; Clilverd, M. A., Clarke, E., Ulich, T., Rishbeth, H., and Jarvis, M. J.: Predicting Solar Cycle 24 and beyond, Space Weather, 4, S09005, doi:10.1029/2005SW000207, 2006.; Emmert, J. T., Lean, J. L., and Picone, J. M.: Record-low thermospheric density during the 2008 solar minimum, Geophys. Res. Lett., 37, L12102, doi:10.1029/2010GL043671, 2010.; Gentile, L. C., Burke, W. J., Roddy, P. A., Retterer, J. M., and Tsunoda, R. T.: Climatology of plasma density depletions observed by DMSP in the dawn sector, J. Geophys. Res., 116, A03321, doi:10.1029/2010JA016176, 2011.; Hocke, K.: Oscillations of global mean TEC, J. Geophys. Res., 113, A04302, doi:10.102...

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Suckdown, fountain lift, and pressures induced on several tandem jet V/STOL configurations

By: Bellavia, David C. ; Corsiglia, Victor R. ; Kuhn, Richard E; Wardwell, Douglas A.

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; As part of a program to improve the methods for predicting the suckdown and hot gas ingestion for jet V/STOL aircraft in ground effect, a da...

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Inter-instrument Calibration Using Magnetic Field Data from Flux Gate Magnetometer (Fgm) and Electron Drift Instrument (Edi) Onboard Cluster : Volume 3, Issue 2 (30/07/2013)

By: L. Giner; R. Teubenbacher; W. Magnes; F. Plaschke; K.-h. Fornaçon; K.-h. Glassmeier; M. Chutter; W. Baumjohann; M. Steller; H. Vaith; R. Nakamura; C. Carr; R. B. Torbert

Description: Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria. We compare the magnetic field data obtained from the Flux-Gate Magnetometer (FGM) and the magnetic field data deduced from the gyration time of electrons measured by the Electron Drift Instrument (EDI) onboard Cluster to determine the spin axis offset of the FGM measurements. Data are used from orbits with their apogees in the magnetotail, when the magnetic field magnitude was between about 20 nT and 500 nT. Offset determination with the EDI-FGM comparison method is of particular interest for these orbits, because no data from solar wind are available in such orbits to apply the usual calibration methods using the Alfvén waves. In this paper, we examine the effects of the different measurement conditions, such as direction of the magnetic field relative to the spin plane and field magnitude in determining the FGM spin-axis offset, and also take into account the time-of-flight offset of the EDI measurements. It is shown that the method works best when the magnetic field magnitude is less tha...

Acuña, M. H.: Space-based magnetometers, Rev. Sci. Instrum., 73, 3717–3736, doi:10.1063/1.1510570, 2002.; Auster, H. U., Fornacon, K. H., Georgescu, E., Glassmeier, K. H., and Motschmann, U.: Calibration of flux-gate magnetometers using relative motion, Meas. Sci. Technol., 13, 1124–1131, doi:10.1088/0957-0233/13/7/321, 2002.; Auster, H. U., Glassmeier, K. H., Magnes, W., Aydogar, O., Baumjohann, W., Constantinescu, D., Fischer, D., Fornacon, K. H., Georgescu, E., Harvey, P., Hillenmaier, O., Kroth, R., Ludlam, M., Narita, Y., Nakamura, R., Okrafka, K., Plaschke, F., Richter, I., Schwarzl, H., Stoll, B., Valavanoglou, A., and Wiedemann, M.: The THEMIS Fluxgate Magnetometer, Space Sci. Rev., 141, 235–264, doi:10.1007/s11214-008-9365-9, 2008.; Balogh, A.: Planetary magnetic field measurements: missions and instrumentation, Space Sci. Rev., 152, 23–97, doi:10.1007/s11214-010-9643-1, 2010.; Balogh, A., Carr, C. M., Acuña, M...

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A Study of Strong Stability of Distributed Systems

By: Cataltepe, Tayfu

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; The strong stability of distributed systems is studied and the problem of characterizing strongly stable semigroups of operators associated...

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Plos One : the Temporal Dynamics of Early Visual Cortex Involvement in Behavioral Priming, Volume 7

By: Floris P. De Lange

Description : Transcranial magnetic stimulation (TMS) allows for non-invasive interference with ongoing neural processing. Applied in a chronometric design over early visual cortex (EVC), TMS has proved valuable in indicating at which particular time point EVC must remain unperturbed for (conscious) vision to be established. In the current study, we set out to examine the effect of EVC TMS across a broad range of time points, both before (pre-stimulus) and after (post-stimulus) the onset of symbolic visual stimuli. Behavioral priming studies have shown that the behavioral impact of a visual stimulus can be independent from its conscious perception, suggesting two independent neural signatures. To assess whether TMS-induced suppression of visual awareness can be dissociated from behavioral priming in the temporal domain, we thus implemented three different measures of visual processing, namely performance on a standard visual discrimination task, a subjective rating of stimulus visibility, and a visual priming task. To control for non-neural TMS effects, we performed electrooculographical recordings, placebo TMS (sham), and control s...

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Interpreting the convergence of Lyman series absorption lines

By: Jenkins, Edward B

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; Spectra of quasars at high z often show absorption at the Lyman limit from intervening gas systems at intermediate z having N(H) approx. gre...

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Directional Features of the Downshifted Peak Observed in Hf-induced Stimulated Electromagnetic Emission Spectra Obtained Using an Interferometer : Volume 24, Issue 7 (09/08/2006)

By: A. Brekke; B. Isham; M. Grill; E. D. Tereshchenko; T. Hagfors; V. Belyey; R. Yu. Yurik; M. T. Rietveld; B. Z. Khudukon

Description: Polar Geophysical Institute, Murmansk, Russia. A high frequency (HF) ionospheric modification experiment was carried out between 25 September and 8 October 2004, using the EISCAT HF transmitter located near Tromsø, Norway. During this experiment the spectra of the stimulated HF sideband waves (stimulated electromagnetic emission or SEE) induced by the HF pump were observed using an interferometer consisting of three spaced receiving antennas with baselines both along and perpendicular to the meridian, and a multi-channel coherent receiver, installed in the vicinity of the HF facility. The transmitter operated at 4040kHz and its antenna beam was scanned to angles of 0°, 7°, 14°, and 21° south from vertical, pausing 4min at each position. This paper focuses on features of the downshifted peak (DP) emission, which has not been as thoroughly studied as many of the other SEE spectral features observable within the EISCAT pump frequency range. It was found that the signal-weighted direction of the DP source region remained within 5° of magnetic zenith as the HF beam was tilted between 0 and 21° south of vertical...

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Propulsion simulation for magnetically suspended wind tunnel models

By: Joshi, Prakash B. ; Chen, James; Krech, Robert H. ; Lintz, Andrew L. ; Rosen, David I; Beerman, Henry P.

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; The feasibility of simulating propulsion-induced aerodynamic effects on scaled aircraft models in wind tunnels employing Magnetic Suspension...

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The Karlsruhe Dynamo Experiment : Volume 9, Issue 3/4 (30/11/-0001)

By: U. Müller; R. Stieglitz

Description: It has been shown theoretically in the past that homogeneous dynamos may occur in electrically conducting fluids for various vortical velocity fields. Roberts (1972) investigated spatially periodic, infinitely extended fields of vortices which Busse (1978, 1992) confined to a finite cylindrical domain. Based on Busse's vortex arrangement a conceptual design for an experimental homogeneous dynamo has been developed and a test facility was setup at the Forschungszentrum Karlsruhe. The first experiments demonstrated that permanent dynamo action can be generated in a cylindrical container filled with liquid sodium in which by means of guide tubes counterrotating and countercurrent spiral vortices are established. The dynamo is self-exciting and the magnetic field saturates at a mean value for fixed super-critical flow rates. The instantaneous magnetic field fluctuates around this mean value by an order of about 5%. As predicted by theory the mode of the observed magnetic field is non-axisymmetric. In a series of experiments a phase- and a bifurcation diagram has be...

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Preliminary evaluation of space station transmission line in a ring configuration

By: Roth, Mary Elle

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; The results of a preliminary evaluation of a space station type transmission line and commercial transmission lines in a ring configuration...

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A New Formulation for the Ionospheric Cross Polar Cap Potential Including Saturation Effects : Volume 23, Issue 11 (21/12/2005)

By: A. J. Ridley

Description: University of Michigan, Ann Arbor, Michigan, USA. It is known that the ionospheric cross polar cap potential (CPCP) saturates when the interplanetary magnetic field (IMF) Bz becomes very large. Few studies have offered physical explanations as to why the polar cap potential saturates. We present 13 events in which the reconnection electric field (REF) goes above 12mV/m at some time. When these events are examined as typically done in previous studies, all of them show some signs of saturation (i.e., over-prediction of the CPCP based on a linear relationship between the IMF and the CPCP). We show that by taking into account the size of the magnetosphere and the fact that the post-shock magnetic field strength is strongly dependent upon the solar wind Mach number, we can better specify the ionospheric CPCP. The CPCP (Φ) can be expressed as Φ=(10-4v2+11.7B(1-e-Ma/3)sin3(Θ/2)) {rms/9 (where v is the solar wind velocity, B is the combined Y and Z components of the interplane...

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