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Sample records for particle explorer sampex

  1. Small Explorers - Small is beautiful. [Solar, Anomalous, and Magnetospheric Particles Explorer (SAMPEX)

    NASA Technical Reports Server (NTRS)

    Gilman, David

    1990-01-01

    NASA's Small Explorer Program aims to achieve a flight rate of one mission per year in a program of small scientific satellites launched from small expendable launch vehicles. The Program is developing 3 missions for launch in the early 1990's: the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), the Submillimeter Wave Astronomy Satellite (SWAS), and the Fast Auroral Snapshot Explorer (FAST). This paper gives an overview of the program, a description of the selected missions, the approach to developing the missions and the plans for the next Announcement of Opportunity.

  2. SAMPEX

    NASA Technical Reports Server (NTRS)

    Catena, J.; Colon, G.

    1991-01-01

    The DSN (Deep Space Network) mission support requirements for SAMPEX are summarized. SAMPEX is the first mission of the GSFC Small Explorer Satellite program (SMEX). Its primary scientific objectives are to measure the elemental and isotopic composition of solar energetic particles, anomalous cosmic rays, and galactic cosmic rays over the energy range from approximately one to several hundred MeV per nucleon. The SAMPEX mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility.

  3. An overview of the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) mission

    NASA Technical Reports Server (NTRS)

    Baker, Daniel N.; Mason, Glenn M.; Figueroa, Orlando; Colon, G.; Watzin, J. G.; Aleman, Roberto M.

    1993-01-01

    The scientific objective of the NASA Small-class Explorer Mission SAMPEX is summarized. A brief history of the Small Explorer program is provided along with a description of the SAMPEX project development and structure. The spacecraft and scientific instrument configuration is presented. The orbit of SAMPEX has an altitude of 520 by 670 km and an 82 deg inclination. Maximum possible power is provided by articulated solar arrays that point continuously toward the sun. Highly sensitive science instruments point generally toward the local zenith, especially over the terrestrial poles, in order to measure optimally the galactic and solar cosmic ray flux. Energetic magnetospheric particle precipitation is monitored at lower geomagnetic latitudes. The spacecraft uses several innovative approaches including an optical fiber bus, powerful onboard computers, and large solid state memories (instead of tape recorders). Spacecraft communication and data acquisition are discussed, and the space- and ground-segment data flows are summarized. A mission lifetime of 3 years is sought with the goal of extending data acquisition over an even longer portion of the 11-year solar activity cycle.

  4. SAMPEX: New Insights into Solar Energetic Particles

    NASA Astrophysics Data System (ADS)

    Klecker, B.

    2012-12-01

    One of the scientific objectives of SAMPEX (Solar, Anomalous, Magnetospheric Particle EXplorer) was the study of solar energetic particles (SEPs). The low altitude high inclination (82°) orbit of SAMPEX was selected in part to measure SEPs and interplanetary particles (e.g. related to corotating interaction regions) over the polar caps, and to provide the unique capability of determining their charge states, utilizing the rigidity dependent cutoff of the magnetic field of the Earth. The four instruments onboard SAMPEX were novel ion and electron detectors with unprecedented sensitivity, with geometric factors of up to 100 cm2 sr, providing measurements of solar and interplanetary particles with elemental and isotopic resolution over a wide energy range (~0.3 to 70 MeV/nuc for Fe). The high sensitivity of the SAMPEX instrumentation combined with using Earth's magnetic field as a M/Q spectrometer provided the first (and so far only) direct SEP ionic charge measurements at energies up to 10s of MeV/nuc. These measurements showed for the first time evidence of an energy dependence of the mean charge of solar energetic particles, suggesting multiple sources in large SEP events and ion stripping in the low corona. The high sensitivity of the SAMPEX instruments also allowed the measurement of energy spectra over a wide energy range, showing characteristic differences in spectral breaks in large SEP events, and systematic enrichment of heavy isotopes in 3He-rich events. Furthermore, the high time resolution SEP measurements from the polar cap to low latitudes provided an ideal tool to study dynamic variations of the Earth's large scale magnetic field, by measuring cutoff variations during large SEP events. This talk will give an overview of the contributions of SAMPEX to our present understanding of SEPs and also summarize related SAMPEX highlights.

  5. The Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) yo-yo despin and solar array deployment mechanism

    NASA Technical Reports Server (NTRS)

    Kellogg, James W.

    1993-01-01

    The SAMPEX spacecraft, successfully launched in July 1992, carried a yo-yo despin system and deployable solar arrays. The despin and solar array mechanisms formed an integral system as the yo-yo cables held the solar array release mechanism in place. The SAMPEX design philosophy was to minimize size and weight through the use of a predominantly single string system. The design challenge was to build a system in a limited space, which was reliable with minimal redundancy. This paper covers the design and development of the SAMPEX yo-yo despin and solar array deployment mechanisms. The problems encountered during development and testing will also be discussed.

  6. New magnetospheric results from the SAMPEX mission

    SciTech Connect

    Baker, D.N.; Blake, J.B.; Callis, L.B.; Hovestadt, D.; Kanekal, S.; Mewaldt, R.A.; Nakamura, R.

    1996-07-01

    Results are described from energetic particle detectors onboard the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) satellite. Electron data are shown for energies {ital E}{gt}400 keV in the outer zone of electron trapping ({ital L}{approx_gt}3). The processes by which electrons are accelerated to very high energies ({ital E}{gt}1 MeV) are discussed. Data are sorted according to {ital L}-values and are compared with concurrent solar wind and geomagnetic conditions. Data from SAMPEX are also compared to GOES and UARS measurements. It is found that high-speed solar wind streams drive the acceleration and recirculation of electrons throughout the outer zone on time scales of one day (or less). Very high time resolution measurements from SAMPEX show the very sporadic nature of magnetosphere-atmosphere coupling processes. {copyright} {ital 1996 American Institute of Physics.}

  7. SAMPEX Spin Stabilized Mode

    NASA Technical Reports Server (NTRS)

    Tsai, Dean C.; Markley, F. Landis; Watson, Todd P.

    2008-01-01

    The Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), the first of the Small Explorer series of spacecraft, was launched on July 3, 1992 into an 82' inclination orbit with an apogee of 670 km and a perigee of 520 km and a mission lifetime goal of 3 years. After more than 15 years of continuous operation, the reaction wheel began to fail on August 18,2007. With a set of three magnetic torquer bars being the only remaining attitude actuator, the SAMPEX recovery team decided to deviate from its original attitude control system design and put the spacecraft into a spin stabilized mode. The necessary operations had not been used for many years, which posed a challenge. However, on September 25, 2007, the spacecraft was successfully spun up to 1.0 rpm about its pitch axis, which points at the sun. This paper describes the diagnosis of the anomaly, the analysis of flight data, the simulation of the spacecraft dynamics, and the procedures used to recover the spacecraft to spin stabilized mode.

  8. SAMPEX Relativistic Microbursts Observation

    NASA Astrophysics Data System (ADS)

    Liang, X.; Comess, M.; Smith, D. M.; Selesnick, R. S.; Sample, J. G.; Millan, R. M.

    2012-12-01

    Relativistic (>1 MeV) electron microburst precipitation is thought to account for significant relativistic electron loss. We present the statistical and spectral analysis of relativistic microbursts observed by the Proton/Electron Telescope (PET) on board the Solar Anomalous Magnetospheric Particle Explorer(SAMPEX) satellite from 1992 to 2004. Spectrally we find that microbursts are well fit by an exponential energy distribution in the 0.5-4 MeV range with a spectral e-folding energy of E0 < 375 keV. We also discuss the comparison of morning microbursts with events at midnight, which were first identified as microbursts by O'Brien et al. (2004). Finally, we compare the loss-rates due to microbursts and non-microburst precipitation during storm times and averaged over all times.

  9. Solar Cycle Dynamics of Solar, Magnetospheric, and Heliospheric Particles, and Long-Term Atmospheric Coupling: SAMPEX

    NASA Technical Reports Server (NTRS)

    Mason, G. M.; Blake, J. B.; Mewaldt, R. A.; Stone, E. C.; Baker, D. N.; vonRosenvinge, T. T.; Callis, L. B.; Hamilton, D. C.; Klecker, B.; Hovestadt, D.; Scholer, M.

    1997-01-01

    This report summarizes science analysis activities by the SAMPEX mission science team during the period during the period July 1, 1997 through July 1, 1997. Bibliographic entries for 1996 and 1997 to date (July 1997) are included. The SAMPEX science team was extremely active, with 27 articles published or submitted to refereed journals, 17 papers published in their entirety in Conference Proceedings, and 74 contributed papers, seminars, and miscellaneous presentations. The bibliography at the end of this report constitutes the primary description of the research activity. Science highlights are given under the major activity headings, as well as other activities of the team.

  10. Solar Cycle Dynamics of Solar, Magnetospheric, and Heliospheric Particles, and Long-Term Atmospheric Coupling: SAMPEX

    NASA Technical Reports Server (NTRS)

    Mason, G. M.; Blake, J. B.; Mewaldt, R. A.; Stone, E. C.; Baker, D. N.

    1998-01-01

    This report summarizes science analysis activities by the SAMPEX mission science team during the period during the period July 1, 1997 through July 1, 1998. Bibliographic entries for 1997 and 1998 to date (July 1998) are included. The SAMPEX science team was extremely active, with 20 articles published or submitted to refereed journals, 11 papers published in their entirety in Conference Proceedings, and 49 contributed papers, seminars, and miscellaneous presentations. The bibliography at the end of this report constitutes the primary description of the research activity. Science highlights are given under the major activity headings, as well as other activities of the team.

  11. Solar Cycle Dynamics of Solar, Magnetospheric, and Heliospheric Particles, and Long-Term Atmospheric Coupling: SAMPEX

    NASA Technical Reports Server (NTRS)

    Mason, G. M.; Blake, J. B.; Mazur, J. E.; Mewaldt, R. A.; Stone, E. C.; Baker, D. N.; vonRosenvinge, T. T.; Callis, L. B.; Klecker, B.; Hovestadt, D.; Scholer, M.

    2000-01-01

    This final technical report summarizes science analysis activities by the SAMPEX mission science team during the period July 1, 1995 through September 30, 2000. Bibliographic entries for 1995 to date (October 2000) are included. The SAMPEX science team was extremely active, with 72 articles published or submitted to referred journals, 38 papers published in their entirety in Conference Proceedings, and 260 contributed papers, seminars, and miscellaneous presentations. The bibliography at the end of this report constitutes the primary description of the research activity. Science highlights are given under the major activity headings, as well as other activities of the team. One Ph.D. student, Mr. Daniel Williams, completed his thesis at California Institute of Technology based on data from the MAST instrument.

  12. On-board attitude determination and control algorithms for SAMPEX

    NASA Technical Reports Server (NTRS)

    Flatley, Thomas W.; Forden, Josephine K.; Henretty, Debra A.; Lightsey, E. Glenn; Markley, F. Landis

    1990-01-01

    Algorithms for onboard attitude determination and control of the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) were developed. The algorithms include spacecraft ephemeris and geomagnetic field models, attitude determination with 2 degree accuracy, control of pitch axis pointing to the sun and yaw axis pointing away from the Earth to achieve control of pitch axis within 5 degrees of sunline, momentum unloading, and nutation damping. The closed loop simulations were performed on a VAX 8830 using a prototype version of the on-board software.

  13. GaAs/Ge solar panels for the SAMPEX program

    NASA Technical Reports Server (NTRS)

    Dobson, Rodney; Kukulka, Jerry; Dakermanji, George; Roufberg, Lew; Ahmad, Anisa; Lyons, John

    1992-01-01

    GaAs based solar cells have been developed for spacecraft use for several years. However, acceptance and application of these cells for spacecraft missions has been slow because of their high cost and concerns about their integration onto solar panels. Spectrolab has now completed fabrication of solar panels with GaAs/Ge solar cells for a second space program. This paper will focus on the design, fabrication and test of GaAs/Ge solar panels for the Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) Program.

  14. MME-based attitude dynamics identification and estimation for SAMPEX

    NASA Astrophysics Data System (ADS)

    Depena, Juan; Crassidis, John L.; McPartland, Michael D.; Meyer, Thomas J.; Mook, D. Joseph

    1994-05-01

    A method is described for obtaining optimal attitude estimation algorithms for spacecraft lacking attitude rate measurement devices (rate gyros), and then demonstrated using actual flight data from the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) spacecraft. SAMPEX does not have on-board rate sensing, and relies on sun sensors and a three-axis magnetometer for attitude determination. Problems arise since typical attitude estimation is accomplished by filtering measurements of both attitude and attitude rates. Rates are nearly always sampled much more densely than are attitudes. Thus, the absence/loss of rate data normally reduces both the total amount of data available and the sampling density (in time) by a substantial fraction. As a result, the sensitivity of the estimates to model uncertainty and to measurement noise increases. In order to maintain accuracy in the attitude estimates, there is increased need for accurate models of the rotational dynamics. The proposed approach is based on the minimum model error (MME) optimal estimation strategy, which has been successfully applied to estimation of poorly modeled dynamic systems which are relatively sparsely and/or noisily measured. The MME estimates may be used to construct accurate models of the system dynamics (i.e. perform system model identification). Thus, an MME-based approach directly addresses the problems created by absence of attitude rate measurements.

  15. SAMPEX and Relativistic Electron Microbursts

    NASA Astrophysics Data System (ADS)

    Blake, J. B.

    2012-12-01

    The launch of SAMPEX ushered in a new era in the study electron microbursts. Bursty electron precipitation had long been known from rocket and balloon observations but SAMPEX, with its extremely large geometric factor and rapid sampling (100 cm2-sr and 50 samples/sec for electrons > 1 MeV) has provided a far more complete and detailed view for almost two decades of nearly continuous data acquisition. Highlights of these observations will be presented.

  16. Mission Operations Report (MOR) for the Solar, Anomalous, and Magnetosphere Particle Explorer (SAMPEX)

    NASA Technical Reports Server (NTRS)

    1992-01-01

    MISSION OPERATIONS REPORTS are published for use by NASA senior management, as required by NASA Headquarters Management Instruction HQMI 8610. lC, effective November 26, 1991. The purpose of these reports is to provide a documentation system that represents an internal discipline to establish critical discriminators selected in advance to measure mission accomplishment, provide a formal written assessment of mission accomplishment, and provide an accountability of technical achievement. Prelaunch reports are prepared and issued for each flight project just prior to launch. Following launch, updating (Post Launch) reports are issued to provide mission status and progress in meeting mission objectives. Primary distribution of these reports is intended for personnel having program/project management responsibilities.

  17. Charge state of anomalous cosmic-ray nitrogen, oxygen, and neon: SAMPEX observations

    NASA Technical Reports Server (NTRS)

    Klecker, B.; Mcnab, M. C.; Blake, J. B.; Hamilton, D. C.; Hovestadt, D.; Kaestle, H.; Looper, M. D.; Mason, G. M.; Mazur, J. E.; Scholer, M.

    1995-01-01

    We report observations of the ionization state of anomalous cosmic-ray (ACR) nitrogen, oxygen, and neon during the period 1992 October to 1993 May, carried out with instrumentation on the Solar, Anomalous & Magnetospheric Particle Explorer (SAMPEX) spacecraft. The low-altitude (510 x 675 km) and high-inclination (82 deg) orbit enables SAMPEX to sample the interplanetary ACR fluxes on each polar pass and then to observe the cutoff of these fluxes by the geomagnetic field at lower latitudes. The arrival time and direction of each ion is recorded by the instruments, allowing detailed calculations of the particle's trajectory through the Earth's magnetic field and thereby placing upper limits on the ionization state of the particles. We find (a) that ACR nitrogen, oxygen, and neon each contain singly ionized particles and (b) that ACR oxygen is predominantly singly ionized with an upper limit of 10% for higher ionization states. These ionization states confirm theories of ACR origin as neutral interstellar material that is singly ionized near the Sun by UV or charge exchange with the solar wind, and is subsequently accelerated in the outer heliosphere.

  18. Use of nonlinear identification in robust attitude and attitude rate estimation for SAMPEX

    NASA Astrophysics Data System (ADS)

    Mook, D. Joseph; Depena, Juan; Trost, Kelly; Wen, Jung; McPartland, Michael

    1995-05-01

    A method is described for obtaining optimal attitude estimation/identification algorithms for spacecraft lacking attitude rate measurement devices (rate gyros), and then demonstrated using actual flight data from the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) spacecraft. SAMPEX does not have on-board rate sensing, and relies on sun sensors and a three-axis magnetometer for attitude determination. The absence of rate data normally reduces both the total amount of data available and the sampling density (in time) by a substantial fraction. In addition, attitude data is occasionally unavailable (for example, during sun occultation). As a result, the sensitivity of the estimates to model uncertainty and to measurement noise increases. In order to maintain accuracy in the attitude estimates, there is an increased need for accurate models of the rotational dynamics. The Minimum Model Error(MME)/Least Square Correlation(LSC) algorithm accurately identifies an improved model for SAMPEX to be used during periods of complete data loss or extreme noise. The model correction is determined by estimating only one orbit(the identification pass) just prior to the assumed data loss(the prediction pass). The MME estimator correctly predicted the states during the identification phase, but more importantly determines the necessary model correction trajectory, d(t). The LSC algorithm is then used to find this trajectory's functional form, H(x(t)). The results show significant improvement of the new corrected model's attitude estimates as compared to the original uncorrected model's estimates. The possible functional form of the correction term is limited at this point in the study to functions strictly of the estimated states. The results, however, strongly suggest that functions based on the relative position of the satellite may also be possible candidates for future consideration.

  19. SAMPEX relativistic micorbursts: PET spectra and comparison to DREP and balloon microbursts

    NASA Astrophysics Data System (ADS)

    Liang, X.; Comess, M.; Smith, D. M.; Selesnick, R. S.; Sample, J. G.; Millan, R. M.

    2011-12-01

    Relativistic(> 1 MeV) electron microbursts may account for significant relativistic electron losses from the outer belt. We will present the spectral characteristics of relativistic microbursts observed with the Proton/Electron telescope (PET) on board the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX) satellite from 1992 to 2004. We find that these events, concentrated in the morning sector, are well fitted by an exponential spectrum with e-folding energies of 100-375 keV in the 0.5-4 MeV range. We have compared the time-averaged precipitation rate from relativistic microbursts with the time-avearged rate from duskside Relativistic Electron Precipitation (DREP), and find that microbursts appear more important < 1.5 MeV and DREP above 1.5 MeV. The > 100 keV microburst e-folding energies contrast with 16 hours of microburst data from the MeV Auroral X-ray Imaging and Spectroscopy (MAXIS) balloon campaign, which show exponential microburst spectra with folding energies ranging from 50-105 keV. We used the Monte Carlo simulation package GEANT3 calculate the count-rate spectra that would have been expected from MAXIS from the SAMPEX microburst spectra. We use these simulations to address the apparent contradictions between the satellite and balloon pictures of microbursts in anticipation of the upcoming flights of the Balloon Array for RBSP Relativistic Electron Losses (BARREL).

  20. Testing of the on-board attitude determination and control algorithms for SAMPEX

    NASA Technical Reports Server (NTRS)

    Mccullough, Jon D.; Flatley, Thomas W.; Henretty, Debra A.; Markley, F. Landis; San, Josephine K.

    1993-01-01

    Algorithms for on-board attitude determination and control of the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) have been expanded to include a constant gain Kalman filter for the spacecraft angular momentum, pulse width modulation for the reaction wheel command, an algorithm to avoid pointing the Heavy Ion Large Telescope (HILT) instrument boresight along the spacecraft velocity vector, and the addition of digital sun sensor (DSS) failure detection logic. These improved algorithms were tested in a closed-loop environment for three orbit geometries, one with the sun perpendicular to the orbit plane, and two with the sun near the orbit plane - at Autumnal Equinox and at Winter Solstice. The closed-loop simulator was enhanced and used as a truth model for the control systems' performance evaluation and sensor/actuator contingency analysis. The simulations were performed on a VAX 8830 using a prototype version of the on-board software.

  1. Precipitating auroral electrons and lower thermospheric nitric oxide densities: SNOE, POLAR, SAMPEX, and NOAA/POES Comparisons for Geomagnetic Storms in 1998-2001

    NASA Astrophysics Data System (ADS)

    Baker, D. N.; Fisher, T. A.; Barth, C. A.; Mankoff, K. D.; Kanekal, S. G.; Bailey, S. M.; Petrinec, S. M.; Luhmann, J. G.; Mason, G. M.; Mazur, J. E.; Evans, D. S.

    2002-05-01

    Nitric oxide (NO) densities measured at altitudes between 97 and 150 km have been acquired using the UVS sensor onboard the Student Nitric Oxide Explorer (SNOE) spacecraft during the years 1998-2001. These data are compared with energetic electron fluxes (E>25 keV) measured concurrently using a sensitive sensor system (LICA) onboard the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) spacecraft. Geomagnetic storm intervals are examined to determine altitude and latitude variations of NO density as it compares to energetic electron precipitation. A broader statistical analysis is then carried out using daily averages of peak NO densities (at 106 km altitudes) and electron intensities measured by SAMPEX/LICA and by the TED sensor system onboard the NOAA/Polar Orbiting Environmental Satellite (POES) spacecraft. We also use the PIXIE instrument onboard POLAR to obtain global views of 2-12 keV x-rays emanating from the upper atmosphere. This gives a broad synoptic measure of relatively low-energy electron precipitation into the atmosphere. Latitude versus time displays of the UVS, PIXIE, LICA and TED data show excellent temporal and spatial correlations of the data sets. More detailed comparisons help us to assess spectral and local time relationships between auroral particle inputs and lower thermospheric chemical responses. These results are potentially quite important since past modeling has shown that particle inputs are significant for changing the chemistry and subsequent dynamics of the atmosphere.

  2. Relativistic electron acceleration and decay time scales in the inner and outer radiation belts: SAMPEX

    NASA Technical Reports Server (NTRS)

    Baker, D. N.; Blake, J. B.; Callis, L. B.; Cummings, J. R.; Hovestadt, D.; Kanekal, S.; Klecker, B.; Mewaldt, R. A.; Zwickl, R. D.

    1994-01-01

    High-energy electrons have been measured systematically in a low-altitude (520 x 675 km), nearly polar (inclination = 82 deg) orbit by sensitive instruments onboard the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX). Count rate channels with electron energy thresholds ranging from 0.4 MeV to 3.5 MeV in three different instruments have been used to examine relativistic electron variations as a function of L-shell parameter and time. A long run of essentially continuous data (July 1992 - July 1993) shows substantial acceleration of energetic electrons throughout much of the magnetosphere on rapid time scales. This acceleration appears to be due to solar wind velocity enhancements and is surprisingly large in that the radiation belt 'slot' region often is filled temporarily and electron fluxes are strongly enhanced even at very low L-values (L aprroximately 2). A superposed epoch analysis shows that electron fluxes rise rapidly for 2.5 is approximately less than L is approximately less than 5. These increases occur on a time scale of order 1-2 days and are most abrupt for L-values near 3. The temporal decay rate of the fluxes is dependent on energy and L-value and may be described by J = Ke-t/to with t(sub o) approximately equals 5-10 days. Thus, these results suggest that the Earth's magnetosphere is a cosmic electron accelerator of substantial strength and efficiency.

  3. SAMPEX observations of energetic hydrogen isotopes in the inner zone

    NASA Technical Reports Server (NTRS)

    Looper, M. D.; Blake, J. B.; Cummings, J. R.; Mewaldt, R. A.

    1996-01-01

    We report observations of geomagnetically-trapped hydrogen isotopes at low altitudes, near the feet of field lines in the inner zone, made with the PET instrument aboard the SAMPEX satellite. We have mapped protons from 19 to 500 MeV, and have discovered a collocated belt of deuterons, which we have mapped from 18 to 58 MeV/nucleon. We found deuterium at about 1% of the level of the proton flux at the same energy per nucleon, and no tritium at energies of tens of MeV/nucleon with an upper limit of about 0.1% of the proton flux. Protons and deuterons showed similar time dependence, with fluxes approximately tripling from July 1992 to March 1996, and similar pitch-angle dependence. The high-L limits of the proton and deuteron belts as functions of energy were organized by rigidity, as was to be expected if these limits were set for both species by inability of particles to sustain adiabatic motion and stable trapping.

  4. Overview of the 1989 mission selections - A quality thrust in particle astrophysics

    NASA Technical Reports Server (NTRS)

    Jones, W. V.

    1990-01-01

    The particle astrophysics space missions that have been selected in 1989 in response to the NASA Announcement of Opportunity are surveyed. They include the low-energy missions Small Explorer/SAMPEX, Explorer/ACE, and Earth Observing System/POEMS and the high-energy missions Space Station Freedom/Astromag, Astromag/LISA, Astromag/WiZard, Astromag/SCIN-MAGIC, and HNC. The major issues in particle astrophysics that these missions will address are reviewed.

  5. Maps of hydrogen isotopes at low altitudes in the inner zone from SAMPEX observations.

    PubMed

    Looper, M D; Blake, J B; Mewaldt, R A

    1998-01-01

    The PET instrument aboard the SAMPEX satellite has provided us with long-term intra-calibrated observations of geomagnetically trapped protons and deuterons in the inner zone, suitable for use in constraining the low-altitude portions of radiation belt models being developed as successors to AP-8. These observations have been summarized elsewhere (Looper et al., 1996). Here we report a detection of geomagnetically-trapped tritum at energies from 14 to 35 MeV/nuc below L = 1.2, at about 1/8 the flux of deuterium previously reported at that location and at similar energy per nucleon. We also demonstrate the utility of the SAMPEX/PET observations for measuring the east-west anisotropy in the trapped particle flux at low altitudes, which is due to displacement of particle gyrocenters from the position of observation in a region of strong flux gradients. This anisotropy is implicitly ignored in omnidirectional radiation-flux models, but it can be important to mission planners considering how to distribute shielding over the surface of oriented spacecraft in low Earth orbit. PMID:11542886

  6. Low-altitude equatorial ions: A new look with SAMPEX

    NASA Astrophysics Data System (ADS)

    Greenspan, M. E.; Mason, G. M.; Mazur, J. E.

    1999-09-01

    We have used the Low-Energy Ion Composition Analyzer (LICA) instrument on the low altitude, polar orbiting SAMPEX spacecraft to survey energetic ions near the magnetic equator from late 1992 through 1998; that is, through the declining phase of Solar Cycle 22, solar minimum, and into the rise of Solar Cycle 23. This survey gives us a unique opportunity to examine both the long-term variation in the low-altitude equatorial ion population and short-term enhancements that occur during magnetic storms. During the survey period, 40 storms with minimum Dst<=100nT occurred: the majority were accompanied by increases in the equatorial ion flux. Although LICA detects ions with energies far above the bulk of the ring current ion population, the times of the maximum equatorial fluxes clustered around the time of minimum Dst, i.e., the time of maximum ring current energy content. The storm associated flux maxima were unevenly distributed in geographic longitude, with the maximum flux enhancements occurring at longitudes just west of the South Atlantic Anomaly. Except for an increase in 1994, the quiet time monthly average equatorial flux declined steadily from 1992 until early 1998; then it began to rise again. The monthly average equatorial ion fluxes had a very significant correlation with the Ap index during this period (R=0.54), indicating that geomagnetic activity dominated the long-term variation. During the survey, we also discovered enhancements in the equatorial ion flux that occurred shortly after the onsets of three recent, large solar energetic particle events. These enhancements began well before the commencements of the associated geomagnetic storms. The major ion species present were H, He, C, and O, therefore ruling out an ionospheric source. These ions could not have penetrated directly from interplanetary space to the magnetic equator, and we do not understand the mechanism that produces the SEP-associated enhancements.

  7. A Search for Heavy Hydrogen Isotopes in Cosmic-Ray Atmospheric Albedo With SAMPEX/PET

    NASA Astrophysics Data System (ADS)

    Looper, M. D.; Blake, J. B.; Mewaldt, R. A.

    2008-12-01

    Bidoli et al. (2003) reported observations of large abundances of deuterium and tritium relative to hydrogen below a few tens of MeV/nuc among the secondary particles escaping the atmosphere after the impact of primary cosmic rays. The SAMPEX satellite spent much of 1996-1998 spinning at 1 RPM, and since late 2007 it has been back in 1 RPM spin mode again; thus its sensors spend half their time looking downward, allowing atmospheric albedo particles to be observed directly. With the Proton/Electron Telescope (PET), hydrogen isotopes are measured in the energy range from about 18 MeV/nuc to 60 to 500 MeV/nuc depending on species. We have previously used PET to measure deuterium and tritium among the Earth's geomagnetically-trapped particle population; we will report here on the results of a search for these isotopes among atmospheric albedo during solar-activity minimum conditions.

  8. Energetic particle environment in near-Earth orbit.

    PubMed

    Klecker, B

    1996-01-01

    The hazard of exposure to high doses of ionizing radiation is one of the primary concerns of extended manned space missions and a continuous threat for the numerous spacecraft in operation today. In the near-Earth environment the main sources of radiation are solar energetic particles (SEP), galactic cosmic rays (GCR), and geomagnetically trapped particles, predominantly protons and electrons. The intensity of the SEP and GCR source depends primarily on the phase of the solar cycle. Due to the shielding effect of the Earth's magnetic field, the observed intensity of SEP and GCR particles in a near-Earth orbit will also depend on the orbital parameters altitude and inclination. The magnetospheric source strength depends also on these orbital parameters because they determine the frequency and location of radiation belt passes. In this paper an overview of the various sources of radiation in the near-Earth orbit will be given and first results obtained with the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) will be discussed. SAMPEX was launched on 3 July 1992 into a near polar (inclination 82 degrees) low altitude (510 x 675 km) orbit. The SAMPEX payload contains four separate instruments of high sensitivity covering the energy range 0.5 to several hundred MeV/nucleon for ions and 0.4 to 30 MeV for electrons. This low altitude polar orbit with zenith-oriented instrumentation provides a new opportunity for a systematic study of the near-Earth energetic particle environment. PMID:11540369

  9. Microburst measurements by SAMPEX HILT: Micro and Macro temporal coupling of electron decay

    NASA Astrophysics Data System (ADS)

    Kanekal, S. G.; Baker, D. N.; Fennell, J. F.; Klecker, B.; Summerlin, E. J.

    2012-12-01

    We use data collected by the HILT sensor on SAMPEX, to explore relationship between micro and macro temporal processes pertaining to relativistic electron decay. Electron microbursts are rapid short lived precipitation on millisecond time scales which have been suggested as a major loss mechanism of relativistic electrons. We identify and quantify electron microburst characteristics using high resolution measurements made by the HILT sensor. Relativistic electron fluxes can be observed to decay on macroscopic times scales of days as well. We have investigated the correlation between macroscopic electron lifetimes and electron microbursts by quantifying the microburst activity and measuring flux lifetimes. These investigations are carried out during the recovery periods of several geomagnetic storms. We report on the preliminary results our investigations of the interconnection between flux decay times and microbursts.

  10. Advantages of estimating rate corrections during dynamic propagation of spacecraft rates: Applications to real-time attitude determination of SAMPEX

    NASA Technical Reports Server (NTRS)

    Challa, M. S.; Natanson, G. A.; Baker, D. F.; Deutschmann, J. K.

    1994-01-01

    This paper describes real-time attitude determination results for the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), a gyroless spacecraft, using a Kalman filter/Euler equation approach denoted the real-time sequential filter (RTSF). The RTSF is an extended Kalman filter whose state vector includes the attitude quaternion and corrections to the rates, which are modeled as Markov processes with small time constants. The rate corrections impart a significant robustness to the RTSF against errors in modeling the environmental and control torques, as well as errors in the initial attitude and rates, while maintaining a small state vector. SAMPLEX flight data from various mission phases are used to demonstrate the robustness of the RTSF against a priori attitude and rate errors of up to 90 deg and 0.5 deg/sec, respectively, as well as a sensitivity of 0.0003 deg/sec in estimating rate corrections in torque computations. In contrast, it is shown that the RTSF attitude estimates without the rate corrections can degrade rapidly. RTSF advantages over single-frame attitude determination algorithms are also demonstrated through (1) substantial improvements in attitude solutions during sun-magnetic field coalignment and (2) magnetic-field-only attitude and rate estimation during the spacecraft's sun-acquisition mode. A robust magnetometer-only attitude-and-rate determination method is also developed to provide for the contingency when both sun data as well as a priori knowledge of the spacecraft state are unavailable. This method includes a deterministic algorithm used to initialize the RTSF with coarse estimates of the spacecraft attitude and rates. The combined algorithm has been found effective, yielding accuracies of 1.5 deg in attitude and 0.01 deg/sec in the rates and convergence times as little as 400 sec.

  11. Observations of geomagnetically trapped anomalous cosmic rays by SAMPEX

    SciTech Connect

    Selesnick, R.S.; Cummings, J.R.; Mewaldt, R.A.

    1996-07-01

    The first detailed measurements of a belt of geomagnetically trapped heavy ions that originated as interplanetary anomalous cosmic rays (ACRs) are being made by the polar orbiting satellite SAMPEX. The singly ionized interplanetary ACRs are trapped after losing electrons in the upper atmosphere. Their subsequent lifetime against energy loss by ionization of the atmosphere allows them to reach a substantially higher intensity than in interplanetary space. The ACR composition, which includes only elements with high first ionization potentials, is reflected in the trapped ACRs with some bias due to the trapping mechanism. The elements O, N, and Ne are present, while the lower atomic number elements, He and C, are either absent or substantially depleted relative to their interplanetary abundances. The trapping mechanism also determines the location of the ACR belt, which is confined to a narrow region near {ital L}=2, and the pitch-angle distribution of the trapped ACRs, which is nearly isotropic except for the well-defined loss cones. The intensities of the trapped and interplanetary ACRs have been measured by SAMPEX since its July, 1992 launch. Both have been steadily increasing with the approach of the minimum of the solar sunspot cycle. {copyright} {ital 1996 American Institute of Physics.}

  12. Comparison of Geomagnetically-shielded Solar Energetic Proton Fluxes Observed at Geostationary Orbit by GOES and in Low-earth Orbit by SAMPEX, POES and MetOp

    NASA Astrophysics Data System (ADS)

    Rodriguez, J. V.; Mazur, J. E.; Green, J. C.; Machol, J. L.

    2012-12-01

    On the current (13-15) and upcoming (R+) series of NOAA Geostationary Operational Environmental Satellites (GOES), solar protons are observed from each satellite in the eastward and westward directions. Solar protons that arrive at a given location in the inner magnetosphere have energies greater than their geomagnetic cutoffs, which depend on direction of arrival as well as the strength of geomagnetic disturbances. Protons arriving from the west at geostationary orbit (GEO) have much lower geomagnetic cutoff energies than protons arriving from the east. As a result, GOES westward observations of >4 MeV protons are representative of the interplanetary population near Earth and serve as the basis for NOAA's real-time solar radiation storm alerts. While the GOES westward observations are similar to the Solar, Anomalous and Magnetospheric Particle Explorer (SAMPEX) Proton-Electron Telescope (PET) proton observations in the polar cap (above invariant L = 10), GOES eastward observations more closely approximate the PET observations at invariant L = 4-4.5 in low earth orbit (LEO). Therefore, GOES may potentially provide a real-time, two-point estimate of the radial gradient of solar energetic protons between L = 6.6 and L = 4. However, the PET observations at L = 4-4.5 exhibit a much wider range of variability than the GOES eastward observations. Therefore, the purpose of this study is to determine how representative the GOES two-point gradient estimate is as a function of magnetic local time and geographic longitude. The study encompasses the largest solar proton events (SPE) in Solar Cycle 23 and to date in Solar Cycle 24. From April 1998 through December 2006, GOES 10 provides eastward GEO and SAMPEX PET provides LEO observations of large SPEs. The Solar Cycle 24 GEO observations are provided by GOES 13 and 15. From July 1998 to date, the Space Environment Monitors (SEM-2) on the NOAA Polar Operational Environmental Satellites (POES) and EUMETSAT MetOp-A provide SPE

  13. Sub-relativistic and relativistic electron precipitations above diffuse aurora: Conjugate observations of SAMPEX and the all sky TV camera at Syowa Station

    NASA Astrophysics Data System (ADS)

    Kurita, S.; Kadokura, A.; Miyoshi, Y.; Sato, Y.; Misawa, H.; Morioka, A.

    2014-12-01

    It has been widely accepted that diffuse auroras are generated by electron precipitations in the energy range from a few keV to tens keV. Recent simulation results based on the quasi-linear theory showed that the scattering by whistler-mode waves plays an important role in the production of precipitating electrons responsible for diffuse auroras. A test particle simulation on electron-whistler interactions shows that relativistic electrons can be scattered into the loss cone simultaneously with the electrons in the energy range from a few keV to tens keV. Thus, it is expected that relativistic electrons precipitate into the atmosphere in association with diffuse auroras if whistler-mode waves contribute to generation of diffuse auroras. To examine this hypothesis, we investigated conjugate observations of SAMPEX and the all sky camera at Syowa Station on the dawn side, where diffuse auroras are frequently observed. In this study, we show a case study that relativistic electron (> 1 MeV) precipitations observed by SAMPEX are associated with the diffuse aurora observed at Syowa Station. The SAMPEX observation shows that the enhancement of precipitating relativistic electrons is well correlated with that of precipitating > 150 keV and > 400 keV electrons, indicating that electrons in the energy range from a few keV to > 1 MeV precipitate into the atmosphere simultaneously in association with the diffuse aurora. It is observational evidence that whistler mode waves contribute to generation of diffuse auroras.

  14. Interactive methods for exploring particle simulation data

    SciTech Connect

    Co, Christopher S.; Friedman, Alex; Grote, David P.; Vay, Jean-Luc; Bethel, E. Wes; Joy, Kenneth I.

    2004-05-01

    In this work, we visualize high-dimensional particle simulation data using a suite of scatter plot-based visualizations coupled with interactive selection tools. We use traditional 2D and 3D projection scatter plots as well as a novel oriented disk rendering style to convey various information about the data. Interactive selection tools allow physicists to manually classify ''interesting'' sets of particles that are highlighted across multiple, linked views of the data. The power of our application is the ability to correspond new visual representations of the simulation data with traditional, well understood visualizations. This approach supports the interactive exploration of the high-dimensional space while promoting discovery of new particle behavior.

  15. Exploring the Standard Model of Particles

    ERIC Educational Resources Information Center

    Johansson, K. E.; Watkins, P. M.

    2013-01-01

    With the recent discovery of a new particle at the CERN Large Hadron Collider (LHC) the Higgs boson could be about to be discovered. This paper provides a brief summary of the standard model of particle physics and the importance of the Higgs boson and field in that model for non-specialists. The role of Feynman diagrams in making predictions for…

  16. Fully Explorable Horned Particles Hiding Charge

    NASA Astrophysics Data System (ADS)

    Guendelman, Eduardo I.; Vasihoun, Mahary

    2015-01-01

    We study a gauge field subsystem which is of a special non-linear form containing a square-root of the Maxwell term and which previously has been shown to produce a QCD-like confining gauge field dynamics in flat space-time. The condition of finite energy of the system or asymptotic flatness on one side of the horned particle implies that the charged object sitting at the throat expels all the flux it produces into the other side of the horned particle, which turns out to be of a "tube-like" nature. An outside observer in the asymptotically flat universe detects, therefore, apparently neutral object. The hiding of the electric flux behind the tube-like region of a horned particle is the only possible way that a truly charged particle can still be of finite energy, in a theory that in flat space describes confinement...

  17. A Versatile Applet to Explore the Wave Behaviour of Particles

    ERIC Educational Resources Information Center

    Fernandez Palop, J. I.

    2009-01-01

    A pedagogical tool that consists of a Java applet has been developed so that undergraduate students in physics can explore the wave behaviour of particles. The applet executes a simulation in which a two-dimensional wave packet moves towards a slit and an obstacle with variable widths. By changing three parameters, slit width, obstacle width and…

  18. From Low Altitude to High Altitude: Assimilating SAMPEX Data in Global Radiation Belt Models by Quantifying Precipitation and Loss

    NASA Astrophysics Data System (ADS)

    Tu, W.; Reeves, G. D.; Cunningham, G.; Selesnick, R. S.; Li, X.; Looper, M. D.

    2012-12-01

    Since its launch in 1992, SAMPEX has been continuously providing measurements of radiation belt electrons at low altitude, which are not only ideal for the direct quantification of the electron precipitation loss in the radiation belt, but also provide data coverage in a critical region for global radiation belt data assimilation models. However, quantitatively combining high-altitude and low-earth-orbit (LEO) measurements on the same L-shell is challenging because LEO measurements typically contain a dynamic mixture of trapped and precipitating populations. Specifically, the electrons measured by SAMPEX can be distinguished as trapped, quasi-trapped (in the drift loss cone), and precipitating (in the bounce loss cone). To simulate the low-altitude electron distribution observed by SAMPEX/PET, a drift-diffusion model has been developed that includes the effects of azimuthal drift and pitch angle diffusion. The simulation provides direct quantification of the rates and variations of electron loss to the atmosphere, a direct input to our Dynamic Radiation Environment Assimilation Model (DREAM) as the electron loss lifetimes. The current DREAM uses data assimilation to combine a 1D radial diffusion model with observational data of radiation belt electrons. In order to implement the mixed electron measurements from SAMPEX into DREAM, we need to map the SAMPEX data from low altitude to high altitudes. To perform the mapping, we will first examine the well-known 'global coherence' of radiation belt electrons by comparing SAMPEX electron fluxes with the energetic electron data from LANL GEO and GPS spacecraft. If the correlation is good, we can directly map the SAMPEX fluxes to high altitudes based on the global coherence; if not, we will use the derived pitch angle distribution from the drift-diffusion model to map up the field and test the mapping by comparing to the high-altitude flux measurements. Then the globally mapped electron fluxes can be assimilated into DREAM

  19. Autonomous Particle Recognition and Analysis of Carbon Flux Explorer Imagery

    NASA Astrophysics Data System (ADS)

    Hamilton, C. M.; Bishop, J. K.; Wood, T.

    2013-12-01

    The biologically mediated export, or sedimentation, of particulate organic carbon to ocean depths below 100 m is approximately 10 Pg C per year and is highly variable in space and time. Despite the need to understand the biological drivers for export and the depth dependence of carbon remineralization for carbon cycle prediction, there are scant observations of sedimentation dynamics in the upper 1000 m. The Carbon Flux Explorer (CFE) is a robotic ocean profiling system, which combines the Scripps Sounding Oceanographic Lagrangian Observer (SOLO) and the LBNL/Berkeley optical sedimentation recorder. The CFE is designed to conduct high-frequency (hourly) observations of particulate organic and inorganic carbon sedimentation to kilometer depths, absent of ships, in all sea conditions, be reprogrammable and adaptive once deployed, and relay data to shore in near real time via Iridium satellite links for seasons to years. The CFE operates by sequentially imaging settled particles at ~15 micrometer size resolution in transmitted, transmitted cross-polarized, and dark field illumination. At present, these images must be stored on the CFE until recovery. In other words, the CFE is deployable in the context of multi-month long process studies. Here we present progress on particle recognition and quantification methodology, which will enable a 100,000:1 compression of image data needed for efficient satellite telemetry and fully autonomous real-time operation. Our methodology includes corrective thresh-holding, cross imaging comparison, distinction of aggregates from organisms, and the classification of particle properties including particle fractal dimension. We also look at these findings in context of particle vertical velocity, float performance, and oceanic conditions. Data analysis examples drawing on recent CFE missions to California coastal and offshore waters and to the subarctic N Pacific ocean, some lasting 41 days, will be presented.

  20. Duskside Relativistic Electron Precipitation in the SAMPEX data set from 1992-2004

    NASA Astrophysics Data System (ADS)

    Comess, M. D.; Smith, D. M.; Millan, R. M.; Sample, J. G.

    2009-12-01

    Evidence for duskside relativistic electron precipitation (DREP) within the Earth's outer radiation belt has been seen in several sets of high altitude balloon data (MAXIS, MINIS, INTERBOA). The DREP events have a characteristically short timescale. They are the hardest X-ray events seen from balloons with typical energy around 1MeV. They always occur in the evening hemisphere between 12-24 MLT. These events appear to be intense enough that they may represent the dominant loss mechanism in the outer electron belt for relativistic electrons. However, such evidence has rarely been seen in satellite data as DREP have been hard to distinguish from other forms of precipitation such as band precipitation and microbursts. Statistical evidence for duskside relativistic electron precipitations (DREP) is presented based on a survey of data collected by SAMPEX from 1992-2004. Correlations among event duration, intensity, spectral hardness and duskside MLT are observed in this sample.

  1. The Mysterious Universe - Exploring Our World with Particle Accelerators

    SciTech Connect

    Brau, James E

    2010-11-23

    The universe is dark and mysterious, more so than even Einstein imagined. While modern science has established deep understanding of ordinary matter, unidentified elements ("Dark Matter" and "Dark Energy") dominate the structure of the universe, its behavior and its destiny. What are these curious elements? We are now working on answers to these and other challenging questions posed by the universe with experiments at particle accelerators on Earth. Results of this research may revolutionize our view of nature as dramatically as the advances of Einstein and other quantum pioneers one hundred years ago. Professor Brau will explain for the general audience the mysteries, introduce facilities which explore them experimentally and discuss our current understanding of the underlying science. The presentation is at an introductory level, appropriate for anyone interested in physics and astronomy.

  2. The Mysterious Universe - Exploring Our World with Particle Accelerators

    ScienceCinema

    Brau, James E [University of Oregon

    2014-06-25

    The universe is dark and mysterious, more so than even Einstein imagined. While modern science has established deep understanding of ordinary matter, unidentified elements ("Dark Matter" and "Dark Energy") dominate the structure of the universe, its behavior and its destiny. What are these curious elements? We are now working on answers to these and other challenging questions posed by the universe with experiments at particle accelerators on Earth. Results of this research may revolutionize our view of nature as dramatically as the advances of Einstein and other quantum pioneers one hundred years ago. Professor Brau will explain for the general audience the mysteries, introduce facilities which explore them experimentally and discuss our current understanding of the underlying science. The presentation is at an introductory level, appropriate for anyone interested in physics and astronomy.

  3. Prediction of solar particle events for exploration class missions

    SciTech Connect

    Heckman, G. ||

    1993-12-31

    Manned space missions beyond the Earth`s magnetosphere require forecasts of solar activity to insure that crews are safe enough to perform their duties and live normal lives after they complete their missions. Solar flares and associated activity produce temporary increases in the number of ionized particles in interplanetary space near Earth, Mars, and the Moon. These increases, called Solar Particle Events (SPE), typically last a few hours and are a source of radiation intense enough to degrade people`s ability to perform physical activity, to cause lingering after effects such as cancer and cataracts, and in extreme cases, to endanger lives. Crews on missions beyond the protective shield of Earth`s atmosphere and magnetic field can go into storm shelters or take protective chemicals if they have timely forecasts of SPEs. A forecast and observing system for SPEs and associated solar activity is already in place. In this paper, comparisons of forecasts and observations for the past several years are analyzed to identify strengths and shortcomings of the present program. This data indicates that forecasts made tens of minutes to a few hours in advance are rather reliable in forecasting whether SPEs will occur but are less reliable in forecasting the intensity of SPEs. Longer term forecasts, made one to three days in advance, would be useful for planning exploration trips away from protective shelters. Though such forecasts are moderately reliable for solar flares, they are less reliable in forecasting whether a SPE will follow.

  4. Extreme Ultraviolet Explorer attitude determination support with a multimission three-axis stabilized spacecraft flight dynamics support system

    NASA Astrophysics Data System (ADS)

    Harman, Richard; Lee, Michael

    The Extreme Ultraviolet Explorer (EUVE) was launched June 7, 1992 by an expendable Delta 2 launch vehicle. The Flight Dynamics Facility (FDF) at NASA Goddard Space Flight Center used a multimission three-axis stabilized spacecraft (MTASS) Flight Dynamics Support System (FDSS) to support the EUVE launch and mission operations. For EUVE, MTASS has been used to monitor attitude sensor performance, study OBC attitude determination performance, and study attitude perturbations. The current status of these efforts are summarized. After its successful implementation for EUVE, the Upper Atmosphere Research Satellite (UARS), and the Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX), MTASS has demonstrated multimission flight dynamics support systems can effectively bridge the gap between single-mission support systems of the past and future generic systems.

  5. Duskside relativistic electron precipitation as measured by SAMPEX: A statistical survey

    NASA Astrophysics Data System (ADS)

    Comess, Max D.; Smith, David M.; Selesnick, Richard S.; Millan, Robyn M.; Sample, John G.

    2013-08-01

    Evidence for duskside relativistic electron precipitation (DREP) within the Earth's outer radiation belt has historically been seen in a few sets of high altitude balloon data (MAXIS, MINIS, INTERBOA), and in satellite data. We present statistical evidence that the relativistic electron precipitation events from the outer radiation belt with e-folding energies > 0.5 MeV are concentrated in the dusk-to-midnight sector, based on a survey of data collected by the SAMPEX satellite from 1992 to 2004. A correlation between spectral hardness and duskside MLT is observed in our sample, the largest studied to date. Out of 9380 precipitation events within the bounce loss cone, 1048 are observed to have exponentially falling spectra with e-folding energies above 0.5 MeV ("hard events") and 1648 events below 0.2 MeV. Of the hard events, 81% occur within 12 h to 24 h MLT, compared to only 37% of events having e-folding energies below 0.2 MeV. With microbursts removed from this softer population the percentage of duskside events rises to 46%. The hard events occur at slightly elevated levels of geomagnetic activity (Ap and Dst) relative to softer nonmicroburst events, but these correlations are much weaker than for microbursts. The hard events are observed to peak in occurrence at L ~ 5.5, significantly higher than nonmicroburst softer events, even though the opposite might be expected from compression of the magnetosphere due to the more negative average Dst of the hard events. The hard events are most prevalent during the declining phase of the 11 year solar cycle.

  6. Exploring dynamics in living cells by tracking single particles.

    PubMed

    Levi, Valeria; Gratton, Enrico

    2007-01-01

    In the last years, significant advances in microscopy techniques and the introduction of a novel technology to label living cells with genetically encoded fluorescent proteins revolutionized the field of Cell Biology. Our understanding on cell dynamics built from snapshots on fixed specimens has evolved thanks to our actual capability to monitor in real time the evolution of processes in living cells. Among these new tools, single particle tracking techniques were developed to observe and follow individual particles. Hence, we are starting to unravel the mechanisms driving the motion of a wide variety of cellular components ranging from organelles to protein molecules by following their way through the cell. In this review, we introduce the single particle tracking technology to new users. We briefly describe the instrumentation and explain some of the algorithms commonly used to locate and track particles. Also, we present some common tools used to analyze trajectories and illustrate with some examples the applications of single particle tracking to study dynamics in living cells. PMID:17703064

  7. Advances in the Exploration of Particle Dark Matter Signals

    NASA Astrophysics Data System (ADS)

    Fornengo, Nicolao

    2011-10-01

    The particle physics interpretation of the missing-mass, or dark-matter, problem of cosmological and astrophysical nature is going to be posed under deep scrutiny in the next years. From the particle physics side, accelerator physics will deeply test theoretical ideas of new physics beyond the Standard Model, where a particle physics candidate to dark matter is often naturally obtained. From the astrophysical side, many probes are already providing a great deal of independent information on the signals which can be produced by the galactic or extra-galactic dark matter. The ultimate hope is in fact to be able to disentangle a dark matter signal from the various sources of backgrounds and to extract a coherent picture of new physics from the accelerator physics, astrophysics and cosmology side. A very ambitious and far-reaching project, indeed!

  8. Exploring multifunctional potential of commercial ferrofluids by magnetic particle hyperthermia

    NASA Astrophysics Data System (ADS)

    Sakellari, Despoina; Mathioudaki, Stella; Kalpaxidou, Zoi; Simeonidis, Konstantinos; Angelakeris, Makis

    2015-04-01

    In this work we examine a selection of commercially available magnetic iron oxide nanoparticles as candidates for magnetic particle hyperthermia applications combining their primary modality with additional heat triggered actions. Contrary to lab-made magnetic nanoparticles, commercial ferrofluids may be rapidly pushed through the medical approval processes since their applicability has already been addressed successfully (i.e., formulation, reproducibility, toxicity and quality assurance) in conjunction with the strong companies‧ drive in the fast delivery of the new therapy to the patient. Four samples are under study with variable hydrodynamic diameters from two companies (Micromod and Chemicell) consisting of iron-oxide magnetic nanoparticles. The tunable magnetic heating characteristics of the ferrofluids were correlated with particle, field and colloidal solution features. Our work revealed a size-dependent magnetic heating efficiency together with fast thermal response, features that are crucial for adequate thermal efficiency combined with minimum treatment duration and show the potential of such materials as multifunctional theranostic agents.

  9. Exploring Kupffer's Vescicle Through Self Propelled Particle Simulations

    NASA Astrophysics Data System (ADS)

    Lundy, Kassidy; Dasgupta, Agnik; Amack, Jeff; Manning, M. Lisa

    Early development is an important stage in the formation of functional, relatively healthy organisms. In zebrafish embryos, a transient organ in the tailbud called Kupffer's Vescicle (KV) is responsible for the initial left-right (L-R) asymmetry that results in asymmetric organ and tissue placement in the adult zebrafish. Originating as a collection of symmetrically organized monociliated cells, the KV experiences a shift in cell shapes over time that leaves more cells on the anterior or top side of the KV. This arrangement helps to generate a stronger counter-clockwise fluid flow across the anterior side of the organ, which is required for L-R asymmetry. In seeking to understand the source of the shape changes occurring within the KV, we simulate a Self Propelled Particle (SPP) model that includes parameters for cell polarization and speed. We model the KV as a large particle moving in a straight line with constant velocity to mimic the physical forces of the notochord acting on this organ, and we model the surrounding tailbud cells as smaller, slower active particles with an orientation that changes over time due to rotational noise. Our goal is to calculate the forces exerted on the KV by the surrounding tissue, to see if they are sufficient to explain the shape changes we observe in the KV that lead to L-R asymmetry.

  10. Chromatin dynamics during interphase explored by single-particle tracking.

    PubMed

    Levi, Valeria; Gratton, Enrico

    2008-01-01

    Our view of the structure and function of the interphase nucleus has changed drastically in recent years. It is now widely accepted that the nucleus is a well organized and highly compartmentalized organelle and that this organization is intimately related to nuclear function. In this context, chromatin-initially considered a randomly entangled polymer-has also been shown to be structurally organized in interphase and its organization was found to be very important to gene regulation. Relevant and not completely answered questions are how chromatin organization is achieved and what mechanisms are responsible for changes in the positions of chromatin loci in the nucleus. A significant advance in the field resulted from tagging chromosome sites with bacterial operator sequences, and visualizing these tags using green fluorescent protein fused with the appropriate repressor protein. Simultaneously, fluorescence imaging techniques evolved significantly during recent years, allowing observation of the time evolution of processes in living specimens. In this context, the motion of the tagged locus was observed and analyzed to extract quantitative information regarding its dynamics. This review focuses on recent advances in our understanding of chromatin dynamics in interphase with the emphasis placed on the information obtained from single-particle tracking (SPT) experiments. We introduce the basis of SPT methods and trajectory analysis, and summarize what has been learnt by using this new technology in the context of chromatin dynamics. Finally, we briefly describe a method of SPT in a two-photon excitation microscope that has several advantages over methods based on conventional microscopy and review the information obtained using this novel approach to study chromatin dynamics. PMID:18461483

  11. Chromatin dynamics during interphase explored by single particle tracking

    PubMed Central

    Levi, Valeria; Gratton, Enrico

    2009-01-01

    Our view of the structure and function of the interphase nucleus has drastically changed in the last years. It is now widely accepted that the nucleus is a well organized and highly compartmentalized organelle and that this organization is intimately related to nuclear function. In this context, chromatin -initially considered a randomly entangled polymer- has also been shown to be structurally organized in interphase and its organization was found to be very important to gene regulation. Relevant and not completely answered questions are how chromatin organization is achieved and what mechanisms are responsible for changes in the positions of chromatin loci in the nucleus. A significant advance in the field resulted from tagging chromosome sites with bacterial operator sequences, and visualizing these tags using green fluorescent protein fused with the appropriate repressor protein. Simultaneously, fluorescence imaging techniques significantly evolved during the last years allowing the observation of the time evolution of processes in living specimens. In this context, the motion of the tagged locus was observed and analyzed to extract quantitative information regarding its dynamics. This review focuses on recent advances in our understanding of chromatin dynamics in interphase with the emphasis placed on the information obtained from single particle tracking (SPT) experiments. We introduce the basis of SPT methods and trajectories analysis, and summarize what has been learnt by using this new technology in the context of chromatin dynamics. Finally, we briefly describe a method of SPT in a two-photon excitation microscope that has several advantages over methods based on conventional microscopy and review the information obtained by using this novel approach to study chromatin dynamics. PMID:18461483

  12. The Cause of the Hardest Electron Precipitation Events Seen by SAMPEX: a Statistical Survey of Circumstantial Evidence

    NASA Astrophysics Data System (ADS)

    Smith, D. M.; Casavant, E. P.; Comess, M. D.; Selesnick, R.; Millan, R. M.; Sample, J. G.; Liang, X.; Bowers, G. S.; Bortnik, J.; Clausen, L. B. N.

    2015-12-01

    We used spectral information from SAMPEX/PET during the period 1992-2004 to find the spectrally hardest sub-population of MeV electron precipitation events (e-folding energy > 400 keV). Contrary to our expectations based on the model of this class of events as precipitation by electromagnetic cyclotron (EMIC) waves, we find no enhanced plasma density during these events using IMAGE/EUV, we find the peak in magnetic local time (MLT) shifted several hours from the peak of EMIC waves at geosynchronous orbit, and we find that the hardest precipitation events do not correlate with high solar wind proton density as EMIC waves do. We will present first results of a comparison of the hardest SAMPEX events with a data-driven model of EMIC wave occurrence. We will also discuss an alternate model for these hard events: current-sheet scattering (loss of the first adiabatic invariant at field inhomogeneities near midnight). The MLT distribution of the hard precipitation events already provides some circumstantial evidence for this model: as the e-folding energy softens from 700 keV to below 400 keV, the average MLT moves smoothly from about 20h to midnight (see Figure). This is consistent with a picture of electrons lost to current-sheet scattering, which would be expected to scatter the highest-energy electrons (with the largest cyclotron radii) first as the population drifts from dusk to midnight, where the inhomogeneities are thought to be most effective and can reach to lower energies.

  13. Relativistic electron precipitations in association with diffuse aurora: Conjugate observation of SAMPEX and the all-sky TV camera at Syowa Station

    NASA Astrophysics Data System (ADS)

    Kurita, Satoshi; Kadokura, Akira; Miyoshi, Yoshizumi; Morioka, Akira; Sato, Yuka; Misawa, Hiroaki

    2015-06-01

    It has been believed that whistler mode waves can cause relativistic electron precipitations. It has been also pointed out that pitch angle scattering of ˜keV electrons by whistler mode waves results in diffuse auroras. Thus, it is natural to expect relativistic electron precipitations associated with diffuse auroras. Based on a conjugate observation between the SAMPEX spacecraft and the all-sky TV camera at Syowa Station, we report, for the first time, a case in which relativistic electron precipitations are associated with diffuse aurora. The SAMPEX observation shows that the precipitations of > 1 MeV electrons are well accompanied with those of > 150 and > 400 keV electrons. This indicates that electrons in the energy range from several keV to > 1 MeV precipitate into the atmosphere simultaneously. Our result supports the idea that whistler mode waves contribute to both generation of diffuse auroras and relativistic electron precipitations.

  14. Particle Removal by Electrostatic and Dielectrophoretic Forces for Dust Control During Lunar Exploration Missions

    NASA Technical Reports Server (NTRS)

    Calle, C. I.; Buhler, C. R.; McFall, J. L.; Snyder, S. J.

    2009-01-01

    Particle removal during lunar exploration activities is of prime importance for the success of robotic and human exploration of the moon. We report on our efforts to use electrostatic and dielectrophoretic forces to develop a dust removal technology that prevents the accumulation of dust on solar panels and removes dust adhering to those surfaces. Testing of several prototypes showed solar shield output above 90% of the initial potentials after dust clearing.

  15. Exploring cytoplasmic dynamics in zebrafish yolk cells by single particle tracking of fluorescent nanodiamonds

    NASA Astrophysics Data System (ADS)

    Chang, Cheng-Chun; Zhang, Bailin; Li, Che-Yu; Hsieh, Chih-Chien; Duclos, Guillaume; Treussart, François; Chang, Huan-Cheng

    2012-02-01

    Fluorescent nanodiamonds (FNDs) have recently developed into an exciting new tool for bioimaging applications. The material possesses several unique features including high biocompatibility, easy bioconjugation, and perfect photostability, making it a promising optical nanoprobe in vitro as well as in vivo. This work explores the potential application of this novel nanomaterial as a photostable, nontoxic tracer in vivo using zebrafish as a model organism. We introduced FNDs into the yolk of a zebrafish embryo by microinjection at the 1-cell stage. Movements of the injected particles were investigated by using single particle tracking techniques. We observed unidirectional and stop-and-go traffic as part of the intricate cytoplasmic movements in the yolk cell. We determined a velocity in the range of 0.19 - 0.40 μm/s for 40 particles moving along with the axial streaming in the early developmental stage (1 to 2 hours post fertilization) of the zebrafish embryos.

  16. Haze Particles and Condensation in Pluto's Atmosphere Explored through Microphysical Modeling

    NASA Astrophysics Data System (ADS)

    Barth, E. L.

    2014-12-01

    To explore scenarios involving condensation in Pluto's atmosphere, a 1-D microphysics model based on the Community Aerosol and Radiation Model for Atmospheres (CARMA) has been developed. CARMA has been used successfully many times to explore the vertical distribution, size, shape, and composition of particles in Titan's atmosphere, and in particular, to predict the appearance of methane condensate layers which were observed at the Huygens' landing site. Physical processes in CARMA include nucleation, condensation, evaporation, sedimentation, and coagulation. In Pluto's atmosphere, most of the condensation would require the presence of a troposphere with at least a few kilometers vertical extent. However, if photochemical production proceeds similarly to the case of Titan's atmosphere, there are possibilities for condensation at higher altitudes as well. A number of sensitivity tests will be presented, including variations in the abundance, size, and shape of haze particles; evaluating the onset of homogeneous methane nucleation; exploring the size distribution of the resulting methane ice particles; and the effects of condensation of other photochemically produced trace species as well.

  17. The effects of heavy particle irradiation on exploration and response to environmental change.

    PubMed

    Casadesus, G; Shukitt-Hale, B; Cantuti-Castelvetri, I; Rabin, B M; Joseph, J A

    2004-01-01

    Free radicals produced by exposure to heavy particles have been found to produce motor and cognitive behavioral toxicity effects in rats similar to those found during aging. The present research was designed to investigate the effects of exposure to 56Fe particles on the ability of male Sprague-Dawley rats to detect novel arrangements in a given environment. Using a test of spatial memory previously demonstrated to be sensitive to aging, open field activity and reaction to spatial and non-spatial changes were measured in a group that received a dose of 1.5 Gy (n=10) of 56Fe heavy particle radiation or in non-radiated controls (n=10). Animals irradiated with 1.5 Gy of 56Fe particles exhibited some age-like effects in rats tested, even though they were, for the most part, subtle. Animals took longer to enter, visited less and spent significantly less time in the middle and the center portions of the open field, independently of total frequency and duration of activity of both groups. Likewise, irradiated subjects spend significantly more time exploring novel objects placed in the open field than did controls. However, irradiated subjects did not vary from controls in their exploration patterns when objects in the open field were spatially rearranged. Thus, irradiation with a dose of 1.5 Gy of 56Fe high-energy particle radiation elicited age-like effects in general open field exploratory behavior, but did not elicit age-like effects during the spatial and non-spatial rearrangement tasks. PMID:15803625

  18. The effects of heavy particle irradiation on exploration and response to environmental change

    NASA Astrophysics Data System (ADS)

    Casadesus, G.; Shukitt-Hale, B.; Cantuti-Castelvetri, I.; Rabin, B. M.; Joseph, J. A.

    2004-01-01

    Free radicals produced by exposure to heavy particles have been found to produce motor and cognitive behavioral toxicity effects in rats similar to those found during aging. The present research was designed to investigate the effects of exposure to 56Fe particles on the ability of male Sprague-Dawley rats to detect novel arrangements in a given environment. Using a test of spatial memory previously demonstrated to be sensitive to aging, open field activity and reaction to spatial and non-spatial changes were measured in a group that received a dose of 1.5 Gy ( n=10) of 56Fe heavy particle radiation or in non-radiated controls ( n=10). Animals irradiated with 1.5 Gy of 56Fe particles exhibited some age-like effects in rats tested, even though they were, for the most part, subtle. Animals took longer to enter, visited less and spent significantly less time in the middle and the center portions of the open field, independently of total frequency and duration of activity of both groups. Likewise, irradiated subjects spend significantly more time exploring novel objects placed in the open field than did controls. However, irradiated subjects did not vary from controls in their exploration patterns when objects in the open field were spatially rearranged. Thus, irradiation with a dose of 1.5 Gy of 56Fe high-energy particle radiation elicited age-like effects in general open field exploratory behavior, but did not elicit age-like effects during the spatial and non-spatial rearrangement tasks.

  19. The effects of heavy particle irradiation on exploration and response to environmental change

    NASA Technical Reports Server (NTRS)

    Casadesus, G.; Shukitt-Hale, B.; Cantuti-Castelvetri, I.; Rabin, B. M.; Joseph, J. A.

    2004-01-01

    Free radicals produced by exposure to heavy particles have been found to produce motor and cognitive behavioral toxicity effects in rats similar to those found during aging. The present research was designed to investigate the effects of exposure to 56Fe particles on the ability of male Sprague-Dawley rats to detect novel arrangements in a given environment. Using a test of spatial memory previously demonstrated to be sensitive to aging, open field activity and reaction to spatial and non-spatial changes were measured in a group that received a dose of 1.5 Gy (n=10) of 56Fe heavy particle radiation or in non-radiated controls (n=10). Animals irradiated with 1.5 Gy of 56Fe particles exhibited some age-like effects in rats tested, even though they were, for the most part, subtle. Animals took longer to enter, visited less and spent significantly less time in the middle and the center portions of the open field, independently of total frequency and duration of activity of both groups. Likewise, irradiated subjects spend significantly more time exploring novel objects placed in the open field than did controls. However, irradiated subjects did not vary from controls in their exploration patterns when objects in the open field were spatially rearranged. Thus, irradiation with a dose of 1.5 Gy of 56Fe high-energy particle radiation elicited age-like effects in general open field exploratory behavior, but did not elicit age-like effects during the spatial and non-spatial rearrangement tasks. Published by Elsevier Ltd on behalf of COSPAR.

  20. Particle astrophysics - The NASA cosmic ray program for the 1990s and beyond

    NASA Technical Reports Server (NTRS)

    Jones, W. V. (Editor); Kerr, Frank J. (Editor); Ormes, Jonathan F. (Editor)

    1990-01-01

    Various papers on particle astrophysics are presented. Individual topics addressed include: the NASA cosmic ray (CR) program for the 1990s and beyond, SAMPEX Mission overview, the Advanced Composition Explorer, Positron Electron Magnet Spectrometer for the Eos Mission, Heavy Nucleus Collector for Space Station, the Astromag Facility, Large Isotope Spectrometer for Astromag, the Solar Probe Mission, the Mercury Dual Orbiter Mission, CRs in the heliosphere, origin of high-energy Galactic CRs, CR studies with the Gamma-Ray Observatory, gamma-ray astronomy at 1 TeV, experimental search for point sources above 1 TeV, the UMC Extensive Air Shower Array, status of the MACRO experiment. Also discussed are: CRs above 1 TeV/n and neutrino astronomy, abundance of ultraheavy nuclei in solar energetic particles, CR studies with an interstellar probe, isotopic composition of CR nuclei beyond the iron peak, experimental studies of CR isotopic composition up to Zr-40, use of accelerators in particle astrophysics, development of long-duration ballooning in Antarctica, Lunar-Based Heavy Nucleus Detector, neutrino astronomy on the moon, gamma rays at airplane altitudes, source composition of CRs.

  1. Exploration of Strongly Coupled Plasma Dynamics and Equilibrium Using the Particle-in-Cell Methodology

    NASA Astrophysics Data System (ADS)

    Rose, D. V.; Welch, D. R.; Genoni, T. C.; Mehlhorn, T. A.; Campbell, R. B.

    2008-03-01

    Particle-based numerical simulations are required to study the dynamics and evolution of inhomogeneous nonequilibrium multispecies strongly coupled plasmas. Molecular dynamics (MD) and particle-in-cell (PIC) techniques and been compared previously [K. Y. Sanbonmatsu, et al., J. Phys. IV (France) 10, Pr5-259 (2000)], with the PIC methodology demonstrating the capability of improved accuracy over the MD simulations at high resolution. However, the PIC simulations were significantly slower, limiting their utility. Here we explore several schemes to improve the computational speed of such calculations including non-iterative, implicit EM field solvers and subgrid models. The simulations are compared directly with the results of Sanbonmatsu, et al., and a new theoretical analysis of the hypernetted chain model where all inter-species correlations are retained [V. Schwarz, et al., Contrib. Plasma Phys. 47, 324 (2007)].

  2. The effects of heavy particle irradiation on exploration and response to environmental change

    NASA Astrophysics Data System (ADS)

    Casadesus, G.; Shukitt-Hale, B.; Cantuti-Castelvetri, I.; Rabin, B.; Joseph, J.

    Free radicals produced by exposure to heavy particles have been found to produce motor and behavioral toxicity effects in rats similar to those found during aging. The present research was designed to investigate the effects of exposure to 56Fe particles on the ability to detect novel arrangements in a given environment of male Sprague-Dawley rats. Using a test of spatial memory previously demonstrated to be sensitive to aging, open-field activity and reaction to spatial and non-spatial changes were measured in a group that received a dose of 1.5 Gy (n=10) of 56Fe heavy particle radiation or in non- radiated controls. Animals irradiated with 1.5 Gy of56Fe particles exhibited some age-like effects in animals tested, even though they were for the most part, subtle. Animals took longer to enter, visited less and spent significantly less time in the middle and the center portions of the open-field independently of total frequency and duration of activity of both groups. Likewise, irradiated subjects reacted significantly more to novel objects placed in the open-field than did controls. However, irradiated subjects did not vary from controls in their exploration patterns when objects in the open-field were spatially rearranged. Thus, irradiation with a dose of 1.5 Gy of 56Fe high-energy particle radiation elicited age-like effects in general open-field exploratory behavior, but did not elicit age- like effects during the spatial and non-spatial rearrangement tasks. Supported by N.A.S.A. Grant NAG9-1190.

  3. Dynamics Explorer measurements of particles, fields, and plasma drifts over a horse-collar auroral pattern

    NASA Technical Reports Server (NTRS)

    Sharber, J. R.; Hones, E. W., Jr.; Heelis, R. A.; Craven, J. D.; Frank, L. A.; Maynard, N. C.; Slavin, J. A.; Birn, J.

    1992-01-01

    As shown from ground-based measurements and satellite-borne imagers, one type of global auroral pattern characteristic of quiet (usually northward IMF) intervals is that of a contracted but thickened emission region of a pattern referred to as 'horse-collar' aurora (Hones et al., 1989). In this report we use the Dynamics Explorer data set to examine a case in which this horse-collar pattern was observed by the DE-1 auroral imager, while at the same time DE-2, at lower altitude, measured precipitating particles, electric and magnetic fields, and plasma drifts. Our analysis shows that, in general, there is close agreement between the optical signatures and the particle precipitation patterns. In many instances, over scales ranging from tens to a few hundred kilometers, electron precipitation features and upward field-aligned currents are observed at locations where the plasma flow gradients indicate negative V-average x E. The particle, plasma, and field measurements made along the satellite track and the 2D perspective of the imager provide a means of determining the configuration of convective flows in the high-latitude ionosphere during this interval of northward IMF. Recent mapping studies are used to relate the low-altitude observations to possible magnetospheric source regions.

  4. The Advanced Composition Explorer Shock Database and Application to Particle Acceleration Theory

    NASA Technical Reports Server (NTRS)

    Parker, L. Neergaard; Zank, G. P.

    2015-01-01

    The theory of particle acceleration via diffusive shock acceleration (DSA) has been studied in depth by Gosling et al. (1981), van Nes et al. (1984), Mason (2000), Desai et al. (2003), Zank et al. (2006), among many others. Recently, Parker and Zank (2012, 2014) and Parker et al. (2014) using the Advanced Composition Explorer (ACE) shock database at 1 AU explored two questions: does the upstream distribution alone have enough particles to account for the accelerated downstream distribution and can the slope of the downstream accelerated spectrum be explained using DSA? As was shown in this research, diffusive shock acceleration can account for a large population of the shocks. However, Parker and Zank (2012, 2014) and Parker et al. (2014) used a subset of the larger ACE database. Recently, work has successfully been completed that allows for the entire ACE database to be considered in a larger statistical analysis. We explain DSA as it applies to single and multiple shocks and the shock criteria used in this statistical analysis. We calculate the expected injection energy via diffusive shock acceleration given upstream parameters defined from the ACE Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) data to construct the theoretical upstream distribution. We show the comparison of shock strength derived from diffusive shock acceleration theory to observations in the 50 keV to 5 MeV range from an instrument on ACE. Parameters such as shock velocity, shock obliquity, particle number, and time between shocks are considered. This study is further divided into single and multiple shock categories, with an additional emphasis on forward-forward multiple shock pairs. Finally with regard to forwardforward shock pairs, results comparing injection energies of the first shock, second shock, and second shock with previous energetic population will be given.

  5. The Advanced Composition Explorer Shock Database and Application to Particle Acceleration Theory

    NASA Technical Reports Server (NTRS)

    Parker, L. Neergaard; Zank, G. P.

    2015-01-01

    The theory of particle acceleration via diffusive shock acceleration (DSA) has been studied in depth by Gosling et al. (1981), van Nes et al. (1984), Mason (2000), Desai et al. (2003), Zank et al. (2006), among many others. Recently, Parker and Zank (2012, 2014) and Parker et al. (2014) using the Advanced Composition Explorer (ACE) shock database at 1 AU explored two questions: does the upstream distribution alone have enough particles to account for the accelerated downstream distribution and can the slope of the downstream accelerated spectrum be explained using DSA? As was shown in this research, diffusive shock acceleration can account for a large population of the shocks. However, Parker and Zank (2012, 2014) and Parker et al. (2014) used a subset of the larger ACE database. Recently, work has successfully been completed that allows for the entire ACE database to be considered in a larger statistical analysis. We explain DSA as it applies to single and multiple shocks and the shock criteria used in this statistical analysis. We calculate the expected injection energy via diffusive shock acceleration given upstream parameters defined from the ACE Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) data to construct the theoretical upstream distribution. We show the comparison of shock strength derived from diffusive shock acceleration theory to observations in the 50 keV to 5 MeV range from an instrument on ACE. Parameters such as shock velocity, shock obliquity, particle number, and time between shocks are considered. This study is further divided into single and multiple shock categories, with an additional emphasis on forward-forward multiple shock pairs. Finally with regard to forward-forward shock pairs, results comparing injection energies of the first shock, second shock, and second shock with previous energetic population will be given.

  6. Exploring methods for compositional and particle size analysis of noble metal nanoparticles in Daphnia magna.

    PubMed

    Krystek, Petra; Brandsma, Sicco; Leonards, Pim; de Boer, Jacob

    2016-01-15

    The identification and quantification of the bioaccumulation of noble metal engineered nanoparticles (ENPs) by aquatic organisms is of great relevance to understand the exposure and potential toxicity mechanisms of nanoscale materials. Four analytical scenarios were investigated in relation to various sized and composed noble metal (gold (Au), platinum (Pt) and silver (Ag)) ENPs during acute, short-term exposure of Daphnia (D.) magna. Next to the total elemental quantification of absorbed ENPs by D. magna, especially information on the size and particle distribution of ENPs in D. magna is of relevance. Dissolution of the exposed biological material prior to measurement by asymmetric flow field flow fractionation coupled to inductively coupled plasma mass spectrometry (AF4-ICPMS) is challenging because the ENPs must stay stable regarding to particle size and composition. Next to dissolution of exposed D. magna by tetra methyl ammonium hydroxide (TMAH), a new enzymatic dissolution approach was explored by using trypsin. The presence of various sized and composed ENPs has been confirmed by AF4-ICPMS but the chosen dissolution medium was crucial for the results. TMAH and trypsin led to comparable results for medium-sized (50nm) noble metals ENPs in exposed D. magna. But it was also shown that the dissolution of biological materials with smaller (<5nm) ENPs led to different results in particle size and elemental concentration depending on the selected dissolution medium. A significant uptake of Au and Pt ENPs by D. magna or adsorption to particles occurred because only 1-5% of the exposed ENPs remained in the exposure medium. PMID:26592609

  7. Solar cycle dynamics of solar, magnetospheric, and heliospheric particles, and long-term atmospheric coupling: SAMPLEX

    NASA Technical Reports Server (NTRS)

    Mason, G. M. (Principal Investigator); Hamilton, D. C.; Blake, J. B.; Mewaldt, R. A.; Stone, E. C.; Baker, D. N.; VonRosenvinge, T. T.; Callis, L. B.; Klecker, B.; Hovestadt, D.; Scholer, M.

    1996-01-01

    This report summarizes science analysis activities by the SAMPEX mission science team during the period during the period July 1, 1995 through July 1, 1996. Bibliographic entries for 1995 and 1996 to date (July 1996) are included. The SAMPEX science team was extremely active, with 20 articles published or submitted to refereed journals, 18 papers published in their entirety in Conference Proceedings, and 53 contributed papers, seminars, and miscellaneous presentations. The bibliography at the end of this report constitutes the primary description of the research activity. Science highlights are given under the major activity headings of anomalous cosmic rays, solar energetic particles, magnetospheric precipitating electrons, trapped H and He isotopes, and data analysis activities.

  8. Development of the Plastic Scintillator Detector Array for the Prototype of the Dark Matter Particle Explorer

    NASA Astrophysics Data System (ADS)

    Zhang, Yongjie; Sun, Zhiyu; Yu, Yuhong; Zhou, Yong; Fang, Fang; Chen, Junling

    2016-07-01

    The scientific object of Dark Matter Particles Explorer(DAMPE) is the measurement of electrons and photons in the range of 5GeV~10TeV and the flux of nuclei up to 500TeV with excellent resolution , and the realization of measurements will identify possible Dark Matter(DM) signature and help deepen our understanding of the origin and propagation of high energy cosmic ray respectively. Plastic Scintillator Detector Array (PSD), which adopts perpendicular structure with two layers and each layer consists of 15 scintillator strips, is one sub-detector of DAMPE for detecting heavy ions and distinguishing photons and electrons. In this paper, the design and some test results of PSD are to be described.

  9. Exploration

    USGS Publications Warehouse

    Wilburn, D.R.; Porter, K.E.

    1999-01-01

    This summary of international nonfuel mineral exploration activities for 1998 draws on available data from literature, industry and US Geological Survey (USGS) specialists. Data on exploration budgets by region and commodity are reported, significant mineral discoveries and exploration target areas are identified and government programs affecting the mineral exploration industry are discussed. Inferences and observations on mineral industry direction are drawn from these data and discussions.

  10. Results of the Alpha-Particle-X-Ray Spectrometer on Board of the Mars Exploration Rovers

    NASA Technical Reports Server (NTRS)

    Geller, R.; Zipfel, J.; Brueckner, J.; Dreibus, G.; Lugmair, G.; Rieder, R.; Waenke, H.; Klingelhoefer, G.; Clark, B. C.; Ming, D. W.

    2005-01-01

    The Mars Exploration Rovers Spirit and Opportunity landed at Gusev crater and Meridiani Planum. The Alpha Particle X-ray Spectrometer (APXS) is part of the instrument suite on both rovers. It is equipped with six 244Cm sources which provide x-ray excitation with alpha-particles (PIXE) and x-ray radiation (XRF). This combination allows x-ray spectroscopy of elements from Na to Br in the energy range of 0.9 to 16 keV. X-ray detectors with a high energy resolution of 160 eV at Fe K allow us to separate even closely spaced energy peaks, such as Na, Mg, Al and Si. The APXS is attached to the rover s arm and provides in-situ measurements of the chemical composition of soils, surfaces of rocks and outcrops and their abraded surfaces. This abstract gives an overview of APXS results obtained during the first year of operation on both landing sites.

  11. Demonstration of a Particle Impact Monitoring System for Crewed Space Exploration Modules

    NASA Technical Reports Server (NTRS)

    Opiela, J. N.; Liou, J.-C.; Corsaro, R.; Giovane, F.; Anz-Meador, P.

    2011-01-01

    When micrometeorite or debris impacts occur on a space habitat, crew members need to be quickly informed of the likely extent of damage, and be directed to the impact location for possible repairs. The goal of the Habitat Particle Impact Monitoring System (HIMS) is to develop a fully automated, end-to-end particle impact detection system for crewed space exploration modules, both in space and on the surfaces of Solar System bodies. The HIMS uses multiple thin film piezo-polymer vibration sensors to detect impacts on a surface, and computer processing of the acoustical signals to characterize the impacts. Development and demonstration of the HIMS is proceeding in concert with NASA's Habitat Demonstration Unit (HDU) Project. The HDU Project is designed to develop and test various technologies, configurations, and operational concepts for exploration habitats. This paper describes the HIMS development, initial testing, and HDU integration efforts. Initial tests of the system on the HDU were conducted at NASA?s 2010 Desert Research and Technologies Studies (Desert-RATS). Four sensor locations were assigned near the corners of a rectangular pattern. To study the influence of wall thickness, three sets of four sensors were installed at different layer depths: on the interior of the PEM wall, on the exterior of the same wall, and on the exterior of a layer of foam insulation applied to the exterior wall. Once the system was activated, particle impacts were periodically applied by firing a pneumatic pellet gun at the exterior wall section. Impact signals from the sensors were recognized by a data acquisition system when they occurred, and recorded on a computer for later analysis. Preliminary analysis of the results found that the HIMS system located the point of impact to within 8 cm, provided a measure of the impact energy / damage produced, and was insensitive to other acoustic events. Based on this success, a fully automated version of this system will be completed and

  12. The relationships between high latitude convection reversals and the energetic particle morphology observed by the Atmosphere Explorer

    NASA Technical Reports Server (NTRS)

    Heelis, R. A.; Winningham, J. D.; Hanson, W. B.; Burch, J. L.

    1980-01-01

    Simultaneous measurements of the auroral zone particle precipitation and the ion convection velocity by Atmosphere Explorer show a consistent difference between the location of the poleward boundary of the auroral particle precipitation and the ion convection reversal. The difference of about 1.5 degrees of invariant latitude is such that some part of the antisunward convection lies wholly within the auroral particle precipitation region. The nature of the convection reversals within the precipitation region suggests that in this region the convection electric field is generated on closed field lines that connect in the magnetosphere to the low latitude boundary layer.

  13. The Orion Exploration Flight Test Post Flight Solid Particle Flight Environment Inspection and Analysis

    NASA Technical Reports Server (NTRS)

    Miller, Joshua E.

    2016-01-01

    Orbital debris in the millimeter size range can pose a hazard to current and planned spacecraft due to the high relative impact speeds in Earth orbit. Fortunately, orbital debris has a relatively short life at lower altitudes due to atmospheric effects; however, at higher altitudes orbital debris can survive much longer and has resulted in a band of high flux around 700 to 1,500 km above the surface of the Earth. While large orbital debris objects are tracked via ground based observation, little information can be gathered about small particles except by returned surfaces, which until the Orion Exploration Flight Test number one (EFT-1), has only been possible for lower altitudes (400 to 500 km). The EFT-1 crew module backshell, which used a porous, ceramic tile system with surface coatings, has been inspected post-flight for potential micrometeoroid and orbital debris (MMOD) damage. This paper describes the pre- and post-flight activities of inspection, identification and analysis of six candidate MMOD impact craters from the EFT-1 mission.

  14. Experimental Exploration of Electrostatic Charge on Particle Pair Relative Velocity in Homogeneous and Isotropic Turbulence

    NASA Astrophysics Data System (ADS)

    Hammond, Adam; Dou, Zhongwang; Tripathi, Anjan; Liang, Zach; Meng, Hui

    2015-11-01

    Study of droplet collision and cloud formation should consider the effects of both turbulence and electrostatic charge on particle dynamics. We present the first experimental observation of radial relative velocity (RV) of charged particles in homogeneous and isotropic turbulence (HIT). Charges on particles were generated through triboelectric effect between the inner wall of the chamber and the particles. To measure charge distribution, a particle-laden head-on impinging flow mimicking our HIT chamber conditions was built and holographic particle tracking was applied to quantify particle charges by measuring their displacements in an electric field. Particles were observed to have opposite charges. Next, in our HIT chamber, we measured particle RV by a novel 4-frame particle tracking velocimetry technique with and without charges on particles, wherein charges were neutralized by coating the interior of the HIT chamber with conductive carbon paint. We compared RV under the same turbulence conditions between charged particles and neutral particles and observed that when particles were oppositely charged, their mean inward RV increased at small separation distances. This result is consistent with recent theory and simulations (Lu and Shaw, Physics of Fluids, 2015). This work was supported by the National Science Foundation through a Collaborative Research Grant CBET-0967407.

  15. Exploring the wake of a dust particle by a continuously approaching test grain

    NASA Astrophysics Data System (ADS)

    Jung, Hendrik; Greiner, Franko; Asnaz, Oguz Han; Carstensen, Jan; Piel, Alexander

    2015-05-01

    The structure of the ion wake behind a dust particle in the plasma sheath of an rf discharge is studied in a two-particle system. The wake formation leads to attractive forces between the negatively charged dust and can cause a reduction of the charge of a particle. By evaluating the dynamic response of the particle system to small external perturbations, these quantities can be measured. Plasma inherent etching processes are used to achieve a continuous mass loss and hence an increasing levitation height of the lower particle, so that the structure of the wake of the upper particle, which is nearly unaffected by etching, can be probed. The results show a significant modification of the wake structure in the plasma sheath to one long potential tail.

  16. Exploring the wake of a dust particle by a continuously approaching test grain

    SciTech Connect

    Jung, Hendrik Greiner, Franko; Asnaz, Oguz Han; Piel, Alexander; Carstensen, Jan

    2015-05-15

    The structure of the ion wake behind a dust particle in the plasma sheath of an rf discharge is studied in a two-particle system. The wake formation leads to attractive forces between the negatively charged dust and can cause a reduction of the charge of a particle. By evaluating the dynamic response of the particle system to small external perturbations, these quantities can be measured. Plasma inherent etching processes are used to achieve a continuous mass loss and hence an increasing levitation height of the lower particle, so that the structure of the wake of the upper particle, which is nearly unaffected by etching, can be probed. The results show a significant modification of the wake structure in the plasma sheath to one long potential tail.

  17. Stochastic Set-Based Particle Swarm Optimization Based on Local Exploration for Solving the Carpool Service Problem.

    PubMed

    Chou, Sheng-Kai; Jiau, Ming-Kai; Huang, Shih-Chia

    2016-08-01

    The growing ubiquity of vehicles has led to increased concerns about environmental issues. These concerns can be mitigated by implementing an effective carpool service. In an intelligent carpool system, an automated service process assists carpool participants in determining routes and matches. It is a discrete optimization problem that involves a system-wide condition as well as participants' expectations. In this paper, we solve the carpool service problem (CSP) to provide satisfactory ride matches. To this end, we developed a particle swarm carpool algorithm based on stochastic set-based particle swarm optimization (PSO). Our method introduces stochastic coding to augment traditional particles, and uses three terminologies to represent a particle: 1) particle position; 2) particle view; and 3) particle velocity. In this way, the set-based PSO (S-PSO) can be realized by local exploration. In the simulation and experiments, two kind of discrete PSOs-S-PSO and binary PSO (BPSO)-and a genetic algorithm (GA) are compared and examined using tested benchmarks that simulate a real-world metropolis. We observed that the S-PSO outperformed the BPSO and the GA thoroughly. Moreover, our method yielded the best result in a statistical test and successfully obtained numerical results for meeting the optimization objectives of the CSP. PMID:26890944

  18. The magic nature of (132)Sn explored through the single-particle states of (133)Sn.

    PubMed

    Jones, K L; Adekola, A S; Bardayan, D W; Blackmon, J C; Chae, K Y; Chipps, K A; Cizewski, J A; Erikson, L; Harlin, C; Hatarik, R; Kapler, R; Kozub, R L; Liang, J F; Livesay, R; Ma, Z; Moazen, B H; Nesaraja, C D; Nunes, F M; Pain, S D; Patterson, N P; Shapira, D; Shriner, J F; Smith, M S; Swan, T P; Thomas, J S

    2010-05-27

    Atomic nuclei have a shell structure in which nuclei with 'magic numbers' of neutrons and protons are analogous to the noble gases in atomic physics. Only ten nuclei with the standard magic numbers of both neutrons and protons have so far been observed. The nuclear shell model is founded on the precept that neutrons and protons can move as independent particles in orbitals with discrete quantum numbers, subject to a mean field generated by all the other nucleons. Knowledge of the properties of single-particle states outside nuclear shell closures in exotic nuclei is important for a fundamental understanding of nuclear structure and nucleosynthesis (for example the r-process, which is responsible for the production of about half of the heavy elements). However, as a result of their short lifetimes, there is a paucity of knowledge about the nature of single-particle states outside exotic doubly magic nuclei. Here we measure the single-particle character of the levels in (133)Sn that lie outside the double shell closure present at the short-lived nucleus (132)Sn. We use an inverse kinematics technique that involves the transfer of a single nucleon to the nucleus. The purity of the measured single-particle states clearly illustrates the magic nature of (132)Sn. PMID:20505723

  19. The magic nature of 132Sn explored through the single-particle states of 133Sn

    SciTech Connect

    Jones, K. L.; Adekola, Aderemi S; Bardayan, Daniel W; Blackmon, Jeff C; Chae, K. Y.; Chipps, K.; Cizewski, J. A.; Erikson, Luke; Harlin, Christopher W; Hatarik, Robert; Kapler, R.; Kozub, R. L.; Liang, J Felix; Livesay, Jake; Ma, Zhanwen; Moazen, Brian; Nesaraja, Caroline D; Nunes, F. M.; Pain, S. D.; Patterson, N. P.; Shapira, Dan; ShrinerJr., J. F.; Smith, Michael Scott; Swan, T. P.; Thomas, J. S.

    2010-05-01

    Atomic nuclei have a shell structure1 in which nuclei with magic numbers of neutrons and protons are analogous to the noble gases in atomic physics. Only ten nuclei with the standard magic numbers of both neutrons and protons have so far been observed. The nuclear shell model is founded on the precept that neutrons and protons can move as independent particles in orbitals with discrete quantum numbers, subject to a mean field generated by all the other nucleons. Knowledge of the properties of single-particle states outside nuclear shell closures in exotic nuclei is important2 5 for a fundamental understanding of nuclear structure and nucleosynthesis (for example the r-process, which is responsible for the production of about half of the heavy elements). However, as a result of their short lifetimes, there is a paucity of knowledge about the nature of single-particle states outside exotic doubly magic nuclei. Here we measure the single-particle character of the levels in 133Sn that lies outside the double shell closure present at the short-lived nucleus 132Sn. We use an inverse kinematics technique that involves the transfer of a single nucleon to the nucleus. The purity of the measured single-particle states clearly illustrates the magic nature of 132Sn.

  20. Exploring the relationship between critical state and particle shape for granular materials

    NASA Astrophysics Data System (ADS)

    Yang, J.; Luo, X. D.

    2015-11-01

    The relationship between critical state and particle shape corresponds to the most fundamental aspect of the mechanics of granular materials. This paper presents an investigation into this relationship through macro-scale and micro-scale laboratory experiments in conjunction with interpretation and analysis in the framework of critical state soil mechanics. Spherical glass beads and crushed angular glass beads of different percentages were mixed with a uniform quartz sand (Fujian sand) to create a sequence of mixtures with varying particle shape. On the micro-scale, particle shape was accurately measured using a laser scanning technique, and was characterized by aspect ratio, sphericity and convexity; a new shape index, taken as the average of the three shape measures and referred to as overall regularity, was proposed to provide a collective characterization of particle shape. On the macro-scale, both undrained and drained triaxial tests were carried out to provide evidence that varying particle shape can alter the overall response as well as the critical states in both stress space and volumetric compression space. The mixtures of Fujian sand and spherical glass beads were found to be markedly more susceptible to liquefaction than the mixtures of Fujian sand and crushed angular glass beads. The change in liquefaction susceptibility was shown to be consistent with the change in the position of the critical state locus (CSL) in the compression space, manifested by a decrease in the intercept and gradient of the CSL due to the presence of spherical glass beads. Quantitative relationships have been established between each of the critical state parameters and each of the shape parameters, thereby providing a way to construct macro-scale constitutive models with intrinsic micro-scale properties built in.

  1. Facile synthesis of methotrexate intercalated layered double hydroxides: particle control, structure and bioassay explore.

    PubMed

    Tian, De-Ying; Liu, Zhen-Lei; Li, Shu-Ping; Li, Xiao-Dong

    2014-12-01

    To study the influence of particle size on drug efficacy and other properties, a series of methotrexate intercalated layered double hydroxides (MTX/LDHs) were synthesized through the traditional coprecipitation method, using a mixture of water and polyethylene glycol (PEG-400) as the solvent. To adjust the particle size of MTX/LDHs, the dropping way, the volume ratio of water to PEG-400 and different hydrothermal treatment time changed accordingly, and the results indicate that the particle size can be controlled between 90 and 140 nm. Elemental C/H/N and inductive coupled plasma (ICP) analysis indicated that different synthesis conditions almost have no effect on the compositions of the nanohybrids. X-ray diffraction (XRD) patterns manifested the successful intercalation of MTX anions into the LDH interlayers, and it's also found out that different volume ratios of water to PEG-400 and variable dropping way can affect the crystallinity of the final samples, i.e., the volume ratio of 3:1 and pH decreasing are proved to be optimum conditions. Furthermore, both antiparallel monolayer and bilayers adopting different orientations are suggested for four samples from XRD results. Fourier transform infrared spectroscopy (FTIR) investigations proved the coexistence of CO3(2-) and MTX anions in the interlayer of the nanohybrids. MTX/LDH particles exhibited hexagonal platelet morphology with round corner and different dropping ways can affect the morphology greatly. Moreover, a DSC study indicated that longer time treatment can weaken the bond between the MTX anions and LDH layers. The kinetic release profiles told us that larger MTX/LDH particles have enhanced the ability of LDH layers to protect interlayer molecules. At last, the bioassay study indicated that the nanohybrids with larger diameters have higher tumor suppression efficiency. PMID:25491832

  2. Exploring conformational modes of macromolecular assemblies by multi-particle cryo-EM

    PubMed Central

    Spahn, Christian M.T.; Penczek, Pawel A.

    2009-01-01

    Summary Single particle cryo-electron microscopy (cryo-EM) is a technique aimed at structure determination of large macromolecular complexes in their unconstrained, physiological conditions. The power of the method has been demonstrated in selected studies where for highly symmetric molecules the resolution attained permitted backbone tracing. However, most molecular complexes appear to exhibit intrinsic conformational variability necessary to perform their functions. Therefore, it is now increasingly recognized that sample heterogeneity constitutes a major methodological challenge for cryo-EM. To overcome it dedicated experimental and particularly computational multi-particle approaches have been developed. Their applications point to the future of cryo-EM as an experimental method uniquely suited to visualize the conformational modes of large macromolecular complexes and machines. PMID:19767196

  3. Exploring Atmospheric Aerosol Chemistry with Advanced High-Resolution Mass Spectrometry and Particle Imaging Methods

    NASA Astrophysics Data System (ADS)

    Nizkorodov, S.

    2014-12-01

    Physical and chemical complexity of atmospheric aerosols presents significant challenges both to experimentalists working on aerosol characterization and to modelers trying to parameterize critical aerosol properties. Multi-modal approaches that combine state-of-the-art experimental, theoretical, and modeling methods are becoming increasingly important in aerosol research. This presentation will discuss recent applications of unique high-resolution mass spectrometry and particle imaging tools developed at two Department of Energy's user facilities, the Environmental Molecular Science Laboratory (EMSL) and Advanced Light Source (ALS), to studies of molecular composition, photochemical aging, and properties of laboratory-generated and field aerosols. Specifically, this presentation will attempt to address the following questions: (a) how do NO2, SO2, and NH3 affect molecular level composition of anthropogenic aerosols?; (b) what factors determine viscosity/surface tension of organic aerosol particles?; (c) how does photolysis affect molecular composition and optical properties of organic aerosols?

  4. Dynamics Explorer measurements of particles, fields, and plasma drifts over a horse-collar auroral pattern

    NASA Technical Reports Server (NTRS)

    Sharber, J. R.; Hones, E. W., Jr.; Heelis, R. A.; Craven, J. D.; Frank, L. A.; Maynard, N. C.; Slavin, J. A.; Birn, J.

    1992-01-01

    As shown from ground-based measurements and satellite-borne imagers, one type of global auroral pattern characteristic of quiet (usually northward IMF) intervals is that of a contracted but thickened emission region in which the dawn and dusk portions can spread poleward to very high latitudes, (the type of a pattern referred to as a 'horse-collar' aurora by Hones et al., 1989). In this report we use a DE data set to examine a case in which this horse-collar pattern was observed by the DE-1 auroral imager while at the same time the DE-2, at lower altitude, measured precipitating particles, electric and magnetic fields, and plasma drifts. There is close agreement between the optical signatures and the particle precipitation patterns. The particle, plasma, and field measurements made along the satellite track and the 2-D perspective of the imager provide a means of determining the configuration of convective flows in the high-latitude ionosphere during this interval of northward IMF. Recent mapping studies are used to relate the low-altitude observations to possible magnetospheric source regions.

  5. Natural gold particles in Eucalyptus leaves and their relevance to exploration for buried gold deposits

    PubMed Central

    Lintern, Melvyn; Anand, Ravi; Ryan, Chris; Paterson, David

    2013-01-01

    Eucalyptus trees may translocate Au from mineral deposits and support the use of vegetation (biogeochemical) sampling in mineral exploration, particularly where thick sediments dominate. However, biogeochemistry has not been routinely adopted partly because biotic mechanisms of Au migration are poorly understood. For example, although Au has been previously measured in plant samples, there has been doubt as to whether it was truly absorbed rather than merely adsorbed on the plant surface as aeolian contamination. Here we show the first evidence of particulate Au within natural specimens of living biological tissue (not from laboratory experimentation). This observation conclusively demonstrates active biogeochemical adsorption of Au and provides insight into its behaviour in natural samples. The confirmation of biogeochemical adsorption of Au, and of a link with abiotic processes, promotes confidence in an emerging technique that may lead to future exploration success and maintain continuity of supply. PMID:24149278

  6. Exploring turbulent energy dissipation and particle energization in space plasmas: the science of THOR mission

    NASA Astrophysics Data System (ADS)

    Retinò, Alessandro

    2016-04-01

    The Universe is permeated by hot, turbulent magnetized plasmas. They are found in active galactic nuclei, supernova remnants, the intergalactic and interstellar medium, as well as in the solar corona, the solar wind and the Earth's magnetosphere. Turbulent plasmas are also found in laboratory devices such as e.g. tokamaks. Our comprehension of the plasma Universe is largely based on measurements of electromagnetic radiation such as light or X-rays which originate from particles that are heated and accelerated as a result of energy dissipation in turbulent environments. Therefore it is of key importance to study and understand how plasma is energized by turbulence. Most of the energy dissipation occurs at kinetic scales, where plasma no longer behaves as a fluid and the properties of individual plasma species (electrons, protons and other ions) become important. THOR (Turbulent Heating ObserveR - http://thor.irfu.se/) is a space mission currently in Study Phase as candidate for M-class mission within the Cosmic Vision program of the European Space Agency. The scientific theme of the THOR mission is turbulent energy dissipation and particle energization in space plasmas, which ties in with ESA's Cosmic Vision science. The main focus is on turbulence and shock processes, however areas where the different fundamental processes interact, such as reconnection in turbulence or shock generated turbulence, are also of high importance. The THOR mission aims to address fundamental questions such as how plasma is heated and particles are accelerated by turbulent fluctuations at kinetic scales, how energy is partitioned among different plasma components and how dissipation operates in different regimes of turbulence. To reach the goal, a careful design of the THOR spacecraft and its payload is ongoing, together with a strong interaction with numerical simulations. Here we present the science of THOR mission and we discuss implications of THOR observations for space

  7. Relativistic magnetic reconnection in collisionless ion-electron plasmas explored with particle-in-cell simulations

    NASA Astrophysics Data System (ADS)

    Melzani, Mickaël; Walder, Rolf; Folini, Doris; Winisdoerffer, Christophe; Favre, Jean M.

    2014-10-01

    Magnetic reconnection is a leading mechanism for magnetic energy conversion and high-energy non-thermal particle production in a variety of high-energy astrophysical objects, including ones with relativistic ion-electron plasmas (e.g., microquasars or AGNs), a regime where first principle studies are scarce. We present 2D particle-in-cell (PIC) simulations of low β ion-electron plasmas under relativistic conditions, i.e., with inflow magnetic energy exceeding the plasma restmass energy. We identify outstanding properties: (i) For relativistic inflow magnetizations (here 10 ≤ σe ≤ 360), the reconnection outflows are dominated by thermal agitation instead of bulk kinetic energy. (ii) At high inflow electron magnetization (σe ≥ 80), the reconnection electric field is sustained more by bulk inertia than by thermal inertia. It challenges the thermal-inertia paradigm and its implications. (iii) The inflows feature sharp transitions at the entrance of the diffusion zones. These are not shocks but results from particle ballistic motions, all bouncing at the same location, provided that the thermal velocity in the inflow is far lower than the inflow E × B bulk velocity. (iv) Island centers are magnetically isolated from the rest of the flow and can present a density depletion at their center. (v) The reconnection rates are slightly higher than in non-relativistic studies. They are best normalized by the inflow relativistic Alfvén speed projected in the outflow direction, which then leads to rates in a close range (0.14-0.25), thus allowing for an easy estimation of the reconnection electric field.

  8. Exploring the Origin of High-Energy Particle Beams in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Chilingarian, Ashot A.

    2014-11-01

    High-energy processes in the magnetosphere and atmosphere such as thunderstorm ground enhancements (TGEs), terrestrial gamma ray flashes (TGFs), and transient luminous events (TLEs) and recently discovered relativistic electron acceleration in the Earth's outer radiation belt trigger various dynamic processes in the Earth's environments and have broad astrophysical relevance. Investigation of the accelerated structures in the geospace plasmas can shed light on particle acceleration to much higher energy in the similar structures of space plasmas in the most distant objects in the universe. The Earth's broad environment is a real laboratory for high-energy astrophysics.

  9. CeREs, A Compact Radiation Belt Explorer to study charged particle dynamics in geospace

    NASA Astrophysics Data System (ADS)

    Kanekal, S. G.; Summerlin, E. J.; Christian, E. R.; Crum, G.; Desai, M. I.; Evans, A.; Dumonthier, J.; Jamison, T.; Jones, A. D.; Livi, S. A.; Ogasawara, K.; Paschalidis, N.; Suarez, G.; Patel, D.

    2015-12-01

    The CeREs 3U CubeSat, set to be launched in mid-2016, will study the physics of the acceleration and loss of radiation belt electrons, particularly loss due to electron microbursts. CeRES will also observe solar electrons and protons entering the magnetosphere via the open field-line polar caps. CeREs is expected to be in a low earth high inclination orbit and carries onboard the Miniaturized Electron pRoton Telescope (MERiT). The MERiT instrument measures electrons and protons ranging in energy from 5 keV to >10 MeV with high time resolution of ~5ms in multiple differential energy channels. MERiT is particle telescope using a stack of solid-state detectors and space-facing avalanche photo diodes.We will describe the CeRES spacecraft, science goals and the MERiT instrument.

  10. The single-particle structure around ^132Sn explored through the (d,p) reaction

    NASA Astrophysics Data System (ADS)

    Jones, Kate

    2007-04-01

    The nuclear shell model^1, originally developed by Maria Geoppert Mayer in 1949 (Nobel Prize 1963) has been used extensively to explain the structure of nuclei. The atomic shell model describes the increased stability observed when an electron shell is filled. Correspondingly, nuclei with magic numbers of protons or neutrons (2, 8, 20, 28, 50, 82, 126) display additional stability. Only ten nuclei to date have been observed which have these standard magic numbers for both neutrons and protons, of these, half are stable or very long-lived. Many changes have been observed in nuclei as we move away from the valley of stability and it is important, both to nuclear structure physics and to understanding the synthesis of nuclei in the cosmos, to understand how these changes affect single-particle states.One exotic doubly-magic nucleus which can be produced with sufficient intensity to perform reactions on it is ^132Sn. Recent calculations^2 have shown that the structure around ^132Sn may affect the freeze out of the rapid neutron capture (r-)process, believed to occur in supernovae, which is responsible for the production of about half the nuclear species heavier than iron. By adding a neutron to a beam of ^132Sn via a transfer reaction, it is possible to study single-particle states beyond the double-shell closure. I will present results from a recent measurement of ^133Sn via the ^132Sn(d,p) reaction in inverse kinematics. [1] Maria Goeppert Mayer, Science 145 999 (1964). [2] R. Surman and J. Engel, Phys. Rev. C 64, 035801 (2001).

  11. Estimation Of Organ Doses From Solar Particle Events For Future Space Exploration Missions

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Cucinotta, Francis A.

    2006-01-01

    Radiation protection practices define the effective dose as a weighted sum of equivalent dose over major organ sites for radiation cancer risks. Since a crew personnel dosimeter does not make direct measurement of the effective dose, it has been estimated with skin-dose measurements and radiation transport codes for ISS and STS missions. If sufficient protection is not provided near solar maximum, the radiation risk can be significant due to exposure to sporadic solar particle events (SPEs) as well as to the continuous galactic cosmic radiation (GCR) on future exploratory-class and long-duration missions. For accurate estimates of overall fatal cancer risks from SPEs, the specific doses at various blood forming organs (BFOs) were considered, because proton fluences and doses vary considerably across marrow regions. Previous estimates of BFO doses from SPEs have used an average body-shielding distribution for the bone marrow based on the computerized anatomical man model (CAM). With the development of an 82-point body-shielding distribution at BFOs, the mean and variance of SPE doses in the major active marrow regions (head and neck, chest, abdomen, pelvis and thighs) will be presented. Consideration of the detailed distribution of bone marrow sites is one of many requirements to improve the estimation of effective doses for radiation cancer risks.

  12. Relationships between field-aligned currents, electric fields and particle precipitation as observed by dynamics Explorer-2

    NASA Technical Reports Server (NTRS)

    Sugiura, M.; Iyemori, T.; Hoffman, R. A.; Maynard, N. C.; Burch, J. L.; Winningham, J. D.

    1983-01-01

    The relationships between field-aligned currents, electric fields, and particle fluxes are determined using observations from the polar orbiting low-altitude satellite Dynamics Explorer-2. It is shown that the north-south electric field and the east-west magnetic field components are usually highly correlated in the field-aligned current regions. This proportionality observationally proves that the field-aligned current equals the divergence of the height-integrated ionospheric Pedersen current in the meridional plane to a high degree of approximation. As a general rule, in the evening sector the upward field-aligned currents flow in the boundary plasma sheet region and the downward currents flow in the central plasma sheet region. The current densities determined independently from the plasma and magnetic field measurements are compared. Although the current densities deduced from the two methods are in general agreement, the degree and extent of the agreement vary in individual cases.

  13. Relationships between field-aligned currents, electric fields, and particle precipitation as observed by Dynamics Explorer-2

    NASA Technical Reports Server (NTRS)

    Sugiura, M.; Iyemori, T.; Hoffman, R. A.; Maynard, N. C.; Burch, J. L.; Winningham, J. D.

    1984-01-01

    The relationships between field-aligned currents, electric fields, and particle fluxes are determined using observations from the polar orbiting low-altitude satellite Dynamics Explorer-2. It is shown that the north-south electric field and the east-west magnetic field components are usually highly correlated in the field-aligned current regions. This proportionality observationally proves that the field-aligned current equals the divergence of the height-integrated ionospheric Pedersen current in the meridional plane to a high degree of approximation. As a general rule, in the evening sector the upward field-aligned currents flow in the boundary plasma sheet region and the downward currents flow in the central plasma sheet region. The current densities determined independently from the plasma and magnetic field measurements are compared. Although the current densities deduced from the two methods are in general agreement, the degree and extent of the agreement vary in individual cases.

  14. Gold grade variation and particle microchemistry in exploration pits of the Batouri gold district, SE Cameroon

    NASA Astrophysics Data System (ADS)

    Vishiti, A.; Suh, C. E.; Lehmann, B.; Egbe, J. A.; Shemang, E. M.

    2015-11-01

    The Batouri area hosts lode-gold mineralization under several-m-thick lateritic cover. Pitting to bed rock on a geochemical Au anomaly defined from previous reconnaissance soil sampling identified five horizons ranging from saprock at the base to laterite at the top. Analysis of bulk samples from each horizon by fire assay shows that most of the horizons are barren although 119 ppb and 48 ppb Au values were obtained from one laterite horizon and one saprolite horizon, respectively, from two separate pits. All the horizons were panned and particulate gold was also recovered only from these two horizons. The gold grains from both horizons are morphologically and compositionally indistinguishable with rare quartz, pyrite and galena inclusions. The grains have irregular, sub-rounded, bean to elongated shapes and they show a remarkable core-rim zonation. Electron microprobe analysis of the grains recorded high gold content in the rims (86.3-100 wt%) and along fissures within the grains (95.1-100 wt%). The cores are relatively Ag rich (11.8-14 wt% Ag) while the rims (0.63-13.7 wt% Ag, most of the values fall within the lower limit of this range) and fissures (0.03-5.02 wt% Ag) are poor in Ag. The low Ag concentration in the rims and along fissures is attributed to preferential leaching of Ag; a process recognized in gold grains and platiniferous alloys from alluvia. The core composition of the grains is similar to that of primary gold composition in the bedrock. These results show that gold in the soil is relic particulate gold derived from the primary source with no evidence of secondary gold precipitation in the weathering cycle. In all the pits no horizon was systematically enriched in gold suggesting there has been no chemical remobilization of gold in this environment. Rather the dispersion of gold here is in the particulate form. Therefore combining particulate gold features with assay data is relevant to exploration in such tropical environments.

  15. Health Risks of Space Exploration: Targeted and Nontargeted Oxidative Injury by High-Charge and High-Energy Particles

    PubMed Central

    Li, Min; Gonon, Géraldine; Buonanno, Manuela; Autsavapromporn, Narongchai; de Toledo, Sonia M.; Pain, Debkumar

    2014-01-01

    Abstract Significance: During deep space travel, astronauts are often exposed to high atomic number (Z) and high-energy (E) (high charge and high energy [HZE]) particles. On interaction with cells, these particles cause severe oxidative injury and result in unique biological responses. When cell populations are exposed to low fluences of HZE particles, a significant fraction of the cells are not traversed by a primary radiation track, and yet, oxidative stress induced in the targeted cells may spread to nearby bystander cells. The long-term effects are more complex because the oxidative effects persist in progeny of the targeted and affected bystander cells, which promote genomic instability and may increase the risk of age-related cancer and degenerative diseases. Recent Advances: Greater understanding of the spatial and temporal features of reactive oxygen species bursts along the tracks of HZE particles, and the availability of facilities that can simulate exposure to space radiations have supported the characterization of oxidative stress from targeted and nontargeted effects. Critical Issues: The significance of secondary radiations generated from the interaction of the primary HZE particles with biological material and the mitigating effects of antioxidants on various cellular injuries are central to understanding nontargeted effects and alleviating tissue injury. Future Directions: Elucidation of the mechanisms underlying the cellular responses to HZE particles, particularly under reduced gravity and situations of exposure to additional radiations, such as protons, should be useful in reducing the uncertainty associated with current models for predicting long-term health risks of space radiation. These studies are also relevant to hadron therapy of cancer. Antioxid. Redox Signal. 20, 1501–1523. PMID:24111926

  16. Biking with Particles: Junior Triathletes' Learning about Drafting through Exploring Agent-Based Models and Inventing New Tactics

    ERIC Educational Resources Information Center

    Hirsh, Alon; Levy, Sharona T.

    2013-01-01

    The present research addresses a curious finding: how learning physical principles enhanced athletes' biking performance but not their conceptual understanding. The study involves a model-based triathlon training program, Biking with Particles, concerning aerodynamics of biking in groups (drafting). A conceptual framework highlights several…

  17. Explore the high-density QCD medium via particle correlations in pPb collisions at CMS

    SciTech Connect

    Li, Wei

    2015-01-15

    The observation of a long-range, near-side two-particle correlation (“ridge”) in very high multiplicity proton–proton and proton–lead collisions has opened up new opportunity of studying novel QCD phenomena in small collision systems. In 2013, high luminosity pPb data were collected by the CMS experiment at the LHC. New results of two- and multi-particle correlations in pPb collisions from CMS are presented over a wide event multiplicity and transverse momentum range. A direct comparison of pPb and PbPb systems is provided. Physics implications, especially in the context of color glass condensate and hydrodynamics models are also discussed.

  18. Two Years of Chemical Sampling on Meridiani Planum by the Alpha Particle X-Ray Spectrometer Onboard the Mars Exploration Rover Opportunity

    NASA Technical Reports Server (NTRS)

    Bruckner, J.; Gellert, R.; Clark, B.C.; Dreibus, G.; Rieder, R.; Wanke, H.; d'Uston, C.; Economou, T.; Klingelhofer, G.; Lugmair, G.; Ming, D.W.; Squyres, S.W.; Yen, A.; Zipfel, J.

    2006-01-01

    For over two terrestrial years, the Mars Exploration Rover Opportunity has been exploring the martian surface at Meridiani Planum using the Athena instrument payload [1], including the Alpha Particle X-Ray Spectrometer (APXS). The APXS has a small sensor head that is mounted on the robotic arm of the rover. The chemistry, mineralogy and morphology of selected samples were investigated by the APXS along with the Moessbauer Spectrometer (MB) and the Microscopic Imager (MI). The Rock Abrasion Tool (RAT) provided the possibility to dust and/or abrade rock surfaces down to several millimeters to expose fresh material for analysis. We report here on APXS data gathered along the nearly 6-kilometers long traverse in craters and plains of Meridiani.

  19. Structural exploration and properties of (H2O)4+ cluster via ab initio in combination with particle swarm optimization method

    NASA Astrophysics Data System (ADS)

    Lv, Zhen-Long; Cheng, Yan; Chen, Xiang-Rong; Cai, Ling-Cang

    2015-05-01

    As a microscopic model to study ionized water, cationic water clusters are hot research subjects in these days, which also has many unique properties compared with their neutral counterparts. Here, the isomers of (H2O)4+ cluster were searched by using particle swarm optimization method with the help of quantum chemical calculations. Eighteen stable candidates were obtained after optimization performed at the MP2/aug-cc-pVDZ level. Their relative Gibbs free energies below 350 K, the infrared spectra of the five lowest energy isomers and the electronic characteristics of the representative isomers were investigated. For these isomers, the effect of the zero point vibrational energies, the relationship between the schemes of the isomers and their energies, and the constituents of the most important orbitals were studied, which provide us with much information for further studying this kind of clusters.

  20. Responsive Poly (ɛ-carbobenzyloxy-L-lysine)-based Colloidal Particles: Exploring and Characterizing the Inverse α-Helix to Random Coil Transition in m-Cresol

    NASA Astrophysics Data System (ADS)

    Rosu, Cornelia; Turksen-Selcuk, Sibel; Soto-Cantu, Eric; Russo, Paul S.

    2012-02-01

    Like other synthetic polypeptides, poly (ɛ-carbobenzyloxy-L-lysine), PCBL, exhibits unique properties that make it a good candidate for a broad range of applications and fundamental investigations. This work explores one particular feature found in PCBL in the single solvent, m-cresol: a sharp, reversible coil-to-helix transition at 27^oC. In nature, such polypeptides undergo similar transitions while attached to living cells. Tethering PCBL polymers to spherical silica particles enables the study of effects such as polypeptide chain length, grafting density and core particle curvature in a fundamental way. This can be accomplished in a single, organic solvent without interference from strong pH and salt effects. This presentation will concern steps taken to make such studies a reality. Methods to characterize grafting density have been established, good control has been exerted over the core size and, by some synthetic routes, also the molecular weight of the PCBL chains in the shell. The coil-to-helix transition is observed for some particles but not all.

  1. An exploration of SciDB in the context of emerging technologies for data stores in particle physics and cosmology

    NASA Astrophysics Data System (ADS)

    Malon, D.; van Gemmeren, P.; Weinstein, J.

    2012-06-01

    Traditional relational databases have not always been well matched to the needs of data-intensive sciences, but efforts are underway within the database community to attempt to address many of the requirements of large-scale scientific data management. One such effort is the open-source project SciDB. Since its earliest incarnations, SciDB has been designed for scalability in parallel and distributed environments, with a particular emphasis upon native support for array constructs and operations. Such scalability is of course a requirement of any strategy for large-scale scientific data handling, and array constructs are certainly useful in many contexts, but these features alone do not suffice to qualify a database product as an appropriate technology for hosting particle physics or cosmology data. In what constitutes its 1.0 release in June 2011, SciDB has extended its feature set to address additional requirements of scientific data, with support for user-defined types and functions, for data versioning, and more. This paper describes an evaluation of the capabilities of SciDB for two very different kinds of physics data: event-level metadata records from proton collisions at the Large Hadron Collider (LHC), and the output of cosmological simulations run on very-large-scale supercomputers. This evaluation exercises the spectrum of SciDB capabilities in a suite of tests that aim to be representative and realistic, including, for example, definition of four-vector data types and natural operations thereon, and computational queries that match the natural use cases for these data.

  2. An eastward propagating compressional Pc 5 wave observed by AMPTE/CCE in the postmidnight sector. [Active Magnetospheric Particle Tracer Explorers

    NASA Technical Reports Server (NTRS)

    Takahashi, K.; Mcentire, R. W.; Zanetti, L. J.; Lopez, R. E.; Kistler, L. M.

    1987-01-01

    This paper presents a detailed analysis of a compressional Pc 5 wave observed in the postmidnight sector on July 21, 1986, using data from the magnetometer, the charge-energy-mass spectrometer, and the medium-energy particle analyzer aboard the AMPTE/Charge Composition Explorer (CCE) spacecraft. The Pc 5 wave exhibited harmonically related transverse and compressional magnetic oscillations, modulation of the flux of medium energy protons, and a large azimuthal wave number, i.e., properties that are similar to those of compressional Pc5 waves observed previously at geostationary orbit. The unique observations recorded by the AMPTE/CCE included the occurrence of the wave in the postmidnight sector, its sunward propagation with respect to the spacecraft, and the left-handed polarization of the perturbed magnetic field. In spite of the morphological uniqueness observed, the excitation of the July 21 event is considered to be due to the same type of instability as operates at geostationary orbit.

  3. Application of RVA and Time-Lapse Photography to Explore Effects of Extent of Chlorination, Milling Extraction Rate, and Particle-Size Reduction of Flour on Cake-Baking Functionality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three factors (extent of chlorination, milling extraction rate and particle-size reduction) in the cake-bakeing functionality of Croplan 594W flour were explored by Rapid Visco-Analyzer (RVA) and time-lapse photography. The extent of chlorination and milling extraction rate showed dramatic effects,...

  4. The Alpha Particle X-Ray Spectrometer APXS on the Rosetta lander Philae to explore the surface of comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Klingelhoefer, Goestar; Girones Lopez, Jordi; Schmanke, Dirk; Markovski, Cristina; Brückner, Johannes; d'Uston, Claude; Economu, Tom; Gellert, Ralf

    2015-04-01

    The Rosetta Mission was launched in 2004 with the main objectives to gain a better understanding of the origin and formation of comets and the solar system. After 10 years of cruise Rosetta rendevouded with the comet 67P/Churyumov-Gerasimenko in 2014 to study the nucleus of the comet and its environment. Rosetta consists of an orbiter and a lander (Philae) with 11 and 9 scientific experiments respectively. It did what has never been attempted before, orbiting and landing on a comet. After orbit insertion in August 2014, the main spacecraft will follow the comet for several months to investigate its surface. Subsequently, Philae has been deployed for a safe landing. As part of the lander payload the APXS will measure in situ the chemical composition of the comet's surface and it's changes during the journey of the comet around the sun. The data obtained with the APXS will be used to characterize the surface of the comet, to determine the chemical composition of the dust component, and to compare the dust with known meteorite types. APXS combines an alpha mode for alpha backscattering spectroscopy and an x-ray mode for alpha particle/x-ray induced x-ray spectroscopy (XRF) in one single instrument, being low in mass (640g) and power consumption (1.5 W in operating mode) [4]. The comet surface will be irradiated by a Curium 244 source exciting characteristic x-rays of the elements present in the surface material. The alpha mode will allow detection of elements like C and O and groups of elements with a higher Z. The x-ray-SD-detector will allow the detection of most of the elements from Na up to Ni and above. The design of the Rosetta APX spectrometer is based on the experience gained with the APXS built for Russian and American Mars missions: Mars 96 spacecraft and Mars Pathfinder, MPF [1]. Two APXS were also built for the Mars Exploration Rovers mission of the NASA, MER [2-3]. Acknowledgements This project is funded by the German Space Agency DLR under contracts 50

  5. Effects of Extent of Chlorination, Extraction Rate, and Particle Size Reduction on Flour and Gluten Functionality Explored by Solvent Retention Capacity (SRC) and Mixograph

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chlorination is an essential soft wheat flour treatment for production of high-ratio cakes in the USA, frequently coupled with a post-milling treatment to reduce flour particle size. The effects of extent of chlorination, extraction rate, and particle size reduction on flour and gluten functionalit...

  6. Competing source and loss mechanisms due to wave-particle interactions in Earth's outer radiation belt during the 30 September to 3 October 2012 geomagnetic storm

    NASA Astrophysics Data System (ADS)

    Turner, D. L.; Angelopoulos, V.; Li, W.; Bortnik, J.; Ni, B.; Ma, Q.; Thorne, R. M.; Morley, S. K.; Henderson, M. G.; Reeves, G. D.; Usanova, M.; Mann, I. R.; Claudepierre, S. G.; Blake, J. B.; Baker, D. N.; Huang, C.-L.; Spence, H.; Kurth, W.; Kletzing, C.; Rodriguez, J. V.

    2014-03-01

    Drastic variations of Earth's outer radiation belt electrons ultimately result from various competing source, loss, and transport processes, to which wave-particle interactions are critically important. Using 15 spacecraft including NASA's Van Allen Probes, THEMIS, and SAMPEX missions and NOAA's GOES and POES constellations, we investigated the evolution of the outer belt during the strong geomagnetic storm of 30 September to 3 October 2012. This storm's main phase dropout exhibited enhanced losses to the atmosphere at L* < 4, where the phase space density (PSD) of multi-MeV electrons dropped by over an order of magnitude in <4 h. Based on POES observations of precipitating >1 MeV electrons and energetic protons, SAMPEX >1 MeV electrons, and ground observations of band-limited Pc1-2 wave activity, we show that this sudden loss was consistent with pitch angle scattering by electromagnetic ion cyclotron waves in the dusk magnetic local time sector at 3 < L* < 4. At 4 < L* < 5, local acceleration was also active during the main and early recovery phases, when growing peaks in electron PSD were observed by both Van Allen Probes and THEMIS. This acceleration corresponded to the period when IMF Bz was southward, the AE index was >300 nT, and energetic electron injections and whistler-mode chorus waves were observed throughout the inner magnetosphere for >12 h. After this period, Bz turned northward, and injections, chorus activity, and enhancements in PSD ceased. Overall, the outer belt was depleted by this storm. From the unprecedented level of observations available, we show direct evidence of the competitive nature of different wave-particle interactions controlling relativistic electron fluxes in the outer radiation belt.

  7. A model for the behaviour of the Solar Energetic Particle Events inside Magnetic Clouds

    NASA Astrophysics Data System (ADS)

    Medina, J.; Hidalgo, M. A.

    2006-12-01

    The modulation effects of the solar ejecta over the solar energetic particle event SEPe fluxes (0,5-100 MeV) provided by solar flares have recently been highlighted. Especially important is the behaviour of these fluxes inside MCs where, in spite of the low magnetic field intensities of these interplanetary structures (about 30 nT), a decrease in the population of the energetic particles is observed. In the present work it is shown a simple theoretical model we have developed to analyse the behaviour of those fluxes inside the magnetic clouds (MCs) using, as a starting point, our previous magnetic field model for MCs. The experimental data from ACE, GOES, SAMPEX, SOHO, Ulysses and WIND satellites are presented, both from MC coincident with SEPe and not coincident. This work has been supported by the Spanish Comisión Internacional de Ciencia y Tecnología (CICYT), grant ESP2005-07290-C02-01 and ESP2006-08459 and Madrid Autonomous Community / University of Alcala grant CAM-UAH 2005/007. This work is performed inside COST Action 724.

  8. A program of data synthesis from the ALSEP/CPLEE ALSEP/SIDE, and Explorer 35 magnetometer to investigate lunar terminator and nightside particle fluxes and surface interactions

    NASA Technical Reports Server (NTRS)

    Reasoner, D. L.

    1976-01-01

    Lunar nightside electron fluxes were studied with the aid of the ALSEP/CPLEE and other instruments. The flux events were shown to be due to (a) electrons propagating upstream from the earth's bow shock, (b) electrons thermalized and scattered to the lunar surface by disturbances along the boundary of the lunar solarwind cavity, and (c) solar wind electrons scattered to the lunar surface by lunar limb shocks and/or compressional disturbances. These electrons were identified as a cause of the high night surface negative potentials observed in tha ALSEP/SIDE ion data. A study was also made of the shadowing of magnetotail plasma sheet electrons by interactions between the lunar body and the ambient magnetic field and by interactions between charged particles and lunar remnant magnetic fields. These shadowing effects were shown to modify lunar surface and near-lunar potential distributions.

  9. Wind-driven particle mobility on Mars: Insights from Mars Exploration Rover observations at "El Dorado" and surroundings at Gusev Crater

    USGS Publications Warehouse

    Sullivan, R.; Arvidson, R.; Bell, J.F.; Gellert, Ralf; Golombek, M.; Greeley, R.; Herkenhoff, K.; Johnson, J.; Thompson, S.; Whelley, P.; Wray, J.

    2008-01-01

    The ripple field known as 'El Dorado' was a unique stop on Spirit's traverse where dust-raising, active mafic sand ripples and larger inactive coarse-grained ripples interact, illuminating several long-standing issues of Martian dust mobility, sand mobility, and the origin of transverse aeolian ridges. Strong regional wind events endured by Spirit caused perceptible migration of ripple crests in deposits SSE of El Dorado, erasure of tracks in sandy areas, and changes to dust mantling the site. Localized thermal vortices swept across El Dorado, leaving paths of reduced dust but without perceptibly damaging nearly cohesionless sandy ripple crests. From orbit, winds responsible for frequently raising clay-sized dust into the atmosphere do not seem to significantly affect dunes composed of (more easily entrained) sand-sized particles, a long-standing paradox. This disparity between dust mobilization and sand mobilization on Mars is due largely to two factors: (1) dust occurs on the surface as fragile, low-density, sand-sized aggregates that are easily entrained and disrupted, compared with clay-sized air fall particles; and (2) induration of regolith is pervasive. Light-toned bed forms investigated at Gusev are coarse-grained ripples, an interpretation we propose for many of the smallest linear, light-toned bed forms of uncertain origin seen in high-resolution orbital images across Mars. On Earth, wind can organize bimodal or poorly sorted loose sediment into coarse-grained ripples. Coarse-grained ripples could be relatively common on Mars because development of durable, well-sorted sediments analogous to terrestrial aeolian quartz sand deposits is restricted by the lack of free quartz and limited hydraulic sediment processing. Copyright 2008 by the American Geophysical Union.

  10. The Energetic Particles: Acceleration, Composition, and Transport (EPACT) investigation on the WIND spacecraft

    NASA Astrophysics Data System (ADS)

    von Rosenvinge, T. T.; Barbier, L. M.; Karsch, J.; Liberman, R.; Madden, M. P.; Nolan, T.; Reames, D. V.; Ryan, L.; Singh, S.; Trexel, H.; Winkert, G.; Mason, G. M.; Hamilton, D. C.; Walpole, P.

    1995-02-01

    The Energetic Particles: Acceleration, Composition, and Transport (EPACT) investigation is designed to make comprehensive observations of solar, interplanetary, and galactic particles over wide ranges of charge, mass, energy, and intensity using a combination of 8 different particle telescopes. This paper summarizes the scientific goals of EPACT and provides a detailed description of the instrument design and capabilities. Electrons are measured from 0.2 to 10 MeV, primarily providing time markers for injections of solar particles. Hydrogen is measured from 1.4 to 120 MeV, and Helium is measured from 0.04 to 500 MeV nucl-1. The collection powers and energy ranges for heavier nuclei up to iron are ideal for observations of quiet-time populations such as particles accelerated by interplanetary shocks and the anomalous cosmic rays (thought to be accelerated at the boundary of the heliosphere). The large collection power available is also ideal for observations of3He,4He, and heavier nuclei in impulsive3He-rich solar events. There is even the possibility of observing ultra heavy nuclei (Z>30) in large solar events for the first time. Finally, there is a telescope designed to measure isotopes from He (3.4 55 MeV nucl-1) to Fe (12 230 MeV nucl-1), which is intended for solar particles, the anomalous cosmic rays and galactic cosmic rays. The overall capabilities of EPACT provide scientifically interesting measurements over all phases of the solar cycle. There will also be important opportunities for combined studies with other spacecraft, such as SAMPEX, Ulysses, and Voyagers 1 and 2.

  11. The Alpha Particle X-Ray Spectrometer APXS on the Rosetta lander Philae to explore the surface of comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Girones-Lopez, Jordi; Schmanke, Dirk; Klingelhoefer, Goestar; Maul, Jasmine; Brueckner, Johannes; Duston, Claude; Gellert, Ralf; Klingelhöfer, Göstar

    The Rosetta Mission was launched in 2004 with the main objectives to gain a better under-standing of the origin and formation of comets and the solar system. After 10 years of cruise the comet 67P/Churyumov-Gerasimenko will be reached in 2014 and the lander Philae will be deployed on the surface. As a part of the lander payload the APXS will measure in situ the chemical composition of the comet's surface and it's changes during the journey of the comet towards the sun. APXS combines an alpha mode for alpha backscattering spectroscopy and an x-ray mode for alpha particle/x-ray induced x-ray spectroscopy (XRF) in one single instrument, being low in mass and power consumption. The comet surface will be irradiated by a Curium 244 source exciting characteristic x-rays of the elements present in the surface material. The alpha mode will allow detection of elements like C and O and groups of elements with higher Z. The x-ray-SD-detector will allow the detection of most of the elements from Na up to Ni and above. During the long duration travel to the comet checkouts and software updates of the Rosetta probe and its payload are performed at regular intervals. These are used to opti-mise and improve the quality of the x-ray and alpha-spectra of the APXS. Soon the Rosetta probe will go into a 3 year long hibernation mode. It will awake when approaching it's target, providing us with new exiting data that will shed light on state, evolution and origin of comets and the solar system. Acknowledgements: This project is funded by the German Space Agency DLR under contracts 50 QP 0404 and 50 QP 0902. References: G. Klingelhüfer, J. Brückner, C. d'Uston, R. Gellert, and R. Rieder, The Rosetta Alpha Particle X-ray Spectrometer (APXS), Space Science Reviews, Vol.128 (2007) 383-396; doi:10.1007/s11214-006-9137-3

  12. Exploring laser-wakefield-accelerator regimes for near-term lasers using particle-in-cell simulation in Lorentz-boosted frames

    NASA Astrophysics Data System (ADS)

    Martins, S. F.; Fonseca, R. A.; Lu, W.; Mori, W. B.; Silva, L. O.

    2010-04-01

    Plasma-based acceleration offers compact accelerators with potential applications for high-energy physics and photon sources. The past five years have seen an explosion of experimental results with monoenergetic electron beams up to 1GeV on a centimetre-scale, using plasma waves driven by intense lasers. The next decade will see tremendous increases in laser power and energy, permitting beam energies beyond 10GeV. Leveraging on the Lorentz transformations to bring the laser and plasma spatial scales together, we have reduced the computational time for modelling laser-plasma accelerators by several orders of magnitude, including all the relevant physics. This scheme enables the first one-to-one particle-in-cell simulations of the next generation of accelerators at the energy frontier. Our results demonstrate that, for a given laser energy, choices in laser and plasma parameters strongly affect the output electron beam energy, charge and quality, and that all of these parameters can be optimized.

  13. Elucid—exploring the local universe with the reconstructed initial density field. I. Hamiltonian Markov chain Monte Carlo method with particle mesh dynamics

    SciTech Connect

    Wang, Huiyuan; Mo, H. J.; Yang, Xiaohu; Lin, W. P.; Jing, Y. P.

    2014-10-10

    Simulating the evolution of the local universe is important for studying galaxies and the intergalactic medium in a way free of cosmic variance. Here we present a method to reconstruct the initial linear density field from an input nonlinear density field, employing the Hamiltonian Markov Chain Monte Carlo (HMC) algorithm combined with Particle-mesh (PM) dynamics. The HMC+PM method is applied to cosmological simulations, and the reconstructed linear density fields are then evolved to the present day with N-body simulations. These constrained simulations accurately reproduce both the amplitudes and phases of the input simulations at various z. Using a PM model with a grid cell size of 0.75 h {sup –1} Mpc and 40 time steps in the HMC can recover more than half of the phase information down to a scale k ∼ 0.85 h Mpc{sup –1} at high z and to k ∼ 3.4 h Mpc{sup –1} at z = 0, which represents a significant improvement over similar reconstruction models in the literature, and indicates that our model can reconstruct the formation histories of cosmic structures over a large dynamical range. Adopting PM models with higher spatial and temporal resolutions yields even better reconstructions, suggesting that our method is limited more by the availability of computer resource than by principle. Dynamic models of structure evolution adopted in many earlier investigations can induce non-Gaussianity in the reconstructed linear density field, which in turn can cause large systematic deviations in the predicted halo mass function. Such deviations are greatly reduced or absent in our reconstruction.

  14. Heavy-ion isotopic anomalies in He-3 rich solar particle events

    NASA Astrophysics Data System (ADS)

    Mason, G. M.; Mazur, J. E.; Halmilton, D. C.

    1994-04-01

    We have measured the approximately 1 MeV/nucleon heavy-ion mass composition during a series of (3)He-rich solar particle events during 1992 July using the University of Maryland instrument on the SAMPEX spacecraft. In addition to enhancements of He-3/He-4 of approximately 103 to 104 larger than coronal values, these events also showed typical enhancements of heavy nuclei of up to a factor of approximately 10 compared with large solar particle events. Over the energy range of approximately 0.4 - 4.0 MeV/nucleon the spectra of both he isotopes as well as heavier ions C, N, O, Ne, Mg, Si, S, Ca+Ar, and Fe were found to be power laws in enegy per nucleon with nearly identical spectral indices, indicating that both the He and heavier ions were accelerated by the same mechanism. We obtain upper limits of approximately 15 for possible enrichments of neutron-rich isotopes of C, N, O, and Fe compared to large solar particle events; however, we find Ne-22/Ne-20 = 0.29 +/- 0.10, an enhancement of a factor of 3-4 compared with large solar particle event abundances. We also find evidence of enrichments of approximately 2-3 for Mg-25/Mg-24 and Mg-26/Mg-24, although the uncertainties are large. Thus while at least one of the heavy elements shows isotopic enhancements of neutron-rich isotopes, the mechanisms that produce the extremely large He-3 enrichments apparently do not produce similarly dramatic isotopic anomalies in the heavy nuclei. These observations constrain possible acceleration models and may indicate that the particles are energized in solar coronal locations enhanced in heavy ions.

  15. Biomorphic Explorers

    NASA Technical Reports Server (NTRS)

    Thakoor, Sarita

    1999-01-01

    This paper presents, in viewgraph form, the first NASA/JPL workshop on Biomorphic Explorers for future missions. The topics include: 1) Biomorphic Explorers: Classification (Based on Mobility and Ambient Environment); 2) Biomorphic Flight Systems: Vision; 3) Biomorphic Explorer: Conceptual Design; 4) Biomorphic Gliders; 5) Summary and Roadmap; 6) Coordinated/Cooperative Exploration Scenario; and 7) Applications. This paper also presents illustrations of the various biomorphic explorers.

  16. Participatory Exploration

    NASA Video Gallery

    Kathy Nado delivers a presentation on Participatory Exploration on May 25, 2010, at the NASA Exploration Enterprise Workshop held in Galveston, TX. The purpose of this workshop was to present NASA'...

  17. Exploration Geophysics

    ERIC Educational Resources Information Center

    Savit, Carl H.

    1978-01-01

    Expansion of activity and confirmation of new technological directions characterized several fields of exploration geophysics in 1977. Advances in seismic-reflection exploration have been especially important. (Author/MA)

  18. Particle acceleration by the sun

    NASA Technical Reports Server (NTRS)

    Lin, R. P.

    1986-01-01

    A review is given of the analysis of new observations of energetic particles and energetic secondary emissions obtained over the solar maxium (approx. 1980) by the Solar Maximum mission, Hinotori, the international Sun-Earth Explorer, Helios, Explorer satellites, and Voyager spacecraft. Solar energetic particle events observed in space, He(3)- rich events, solar gamma rays and neutrons, and solar neutrinos are discussed.

  19. News Competition: School team launches a rocket Conference: Norway focuses on physics teaching Science on Stage: Canadian science acts take to the stage Particle Physics: Teachers get a surprise at CERN Teaching: Exploring how students learn physics University: Oxford opens doors to science teachers Lasers: Lasers shine light on meeting Science Fair: Malawi promotes science education

    NASA Astrophysics Data System (ADS)

    2010-11-01

    Competition: School team launches a rocket Conference: Norway focuses on physics teaching Science on Stage: Canadian science acts take to the stage Particle Physics: Teachers get a surprise at CERN Teaching: Exploring how students learn physics University: Oxford opens doors to science teachers Lasers: Lasers shine light on meeting Science Fair: Malawi promotes science education

  20. Exploration Geochemistry.

    ERIC Educational Resources Information Center

    Closs, L. Graham

    1983-01-01

    Contributions in mineral-deposit model formulation, geochemical exploration in glaciated and arid environments, analytical and sampling problems, and bibliographic research were made in symposia held and proceedings volumes published during 1982. Highlights of these symposia and proceedings and comments on trends in exploration geochemistry are…

  1. Generation and Loss of New Inner Belts Associated with Solar Energetic Particle Events: A Perspective from Multiple-Satellite Observations

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Larsen, B. A.; Friedel, R. H.

    2012-12-01

    It is puzzling to observe that some Solar Energetic Particle (SEP) events can generate new proton belts in the inner-belt region but not others. One hypothesis is that the new proton belt is the consequence the double-action from a SEP followed by an interplanetary shock: The former loads a seed population of protons at low L-shells and electric field impulses caused by the latter quickly transport those protons even closer to the Earth and adiabatically accelerate them to very high energies. Regarding the loss, it is often observed that the new proton belt suddenly disappear during a moderate geomagnetic storm, and the popular explanation is due to strengthened scattering from the build-up of the ring current. Here we plan to test the above two theories from multiple-point observations from LEO and HEO satellites, which provide particle measurements, in addition to the OMNI upstream solar wind data and geosynchronous observations. Comparing to HEO, LEO measurements from the NOAA POES fleet and SAMPEX provide particle distributions with a high time-resolution and wide energy coverage. Particle and field data from Polar and THEMIS are also to be used in this study. In accordance with the belt-generation hypothesis, we expect for the generation of a new electron inner-belt along with the new proton belt but with a different energy spectrum due to different sources and acceleration processes. As for the loss process, we will look into in-situ magnetic field measurements to compare with global magnetic field models so as to confirm effects of stretching field lines. By adding electron measurements to the analysis, we expect to help differentiate adiabatic effects from others. Through both case and statistical studies, this work will provide a more thorough test on existing hypothesis and possibly new insights on the generation and loss of SEP-caused proton belts by combing various types of observations from multiple space missions.

  2. Explorer 24

    NASA Technical Reports Server (NTRS)

    1964-01-01

    'This satellite, Explorer 24, was a 12-foot-diameter inflatable sphere developed by an engineering team at Langley. It provided information on complex solar radiation/air-density relationships in the upper atmosphere.' Explorer satellites were inflatable satellites--or satelloons, like Echo, and were developed as a follow-on program. They were intended as a vehicle to study the density of air in the upper atmosphere. Explorer 24 was launched in November 1964. Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, NASA SP-4308, pp. 191-192.

  3. Aerial Explorers

    NASA Technical Reports Server (NTRS)

    Young, Larry A.; Pisanich, Greg; Ippolito, Corey

    2005-01-01

    This paper presents recent results from a mission architecture study of planetary aerial explorers. In this study, several mission scenarios were developed in simulation and evaluated on success in meeting mission goals. This aerial explorer mission architecture study is unique in comparison with previous Mars airplane research activities. The study examines how aerial vehicles can find and gain access to otherwise inaccessible terrain features of interest. The aerial explorer also engages in a high-level of (indirect) surface interaction, despite not typically being able to takeoff and land or to engage in multiple flights/sorties. To achieve this goal, a new mission paradigm is proposed: aerial explorers should be considered as an additional element in the overall Entry, Descent, Landing System (EDLS) process. Further, aerial vehicles should be considered primarily as carrier/utility platforms whose purpose is to deliver air-deployed sensors and robotic devices, or symbiotes, to those high-value terrain features of interest.

  4. Exploring Venus

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2008-01-01

    With a temperature higher than the inside of your oven and atmospheric pressure equal to that a kilometer under the ocean, the surface of Venus is one of the most hostile environments in the solar system, and Venus exploration presents a challenge to technology. This lecture presents mission trade-offs and discusses a proposed mission concept for rover and aircraft based exploration of the surface and atmosphere of Venus. Several approaches to the technology, electronics, mechanical parts, and power systems, are discussed.

  5. Particle separation

    DOEpatents

    Moosmuller, Hans; Chakrabarty, Rajan K.; Arnott, W. Patrick

    2011-04-26

    Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

  6. Particle separation

    NASA Technical Reports Server (NTRS)

    Moosmuller, Hans (Inventor); Chakrabarty, Rajan K. (Inventor); Arnott, W. Patrick (Inventor)

    2011-01-01

    Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

  7. Exploring Television.

    ERIC Educational Resources Information Center

    Kuhns, William

    "Exploring Television" is an inquiry/discovery textbook designed to help students to understand, analyze, criticize, evaluate, and judge the experiences they have had in front of the television set. The text consists of three main parts. "The Medium" inquires into the radio-movie origins of television and prompts research into the networks and…

  8. Exploring Size.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    1995-01-01

    "Exploring" is a magazine of science, art, and human perception that communicates ideas museum exhibits cannot demonstrate easily by using experiments and activities for the classroom. This issue concentrates on size, examining it from a variety of viewpoints. The focus allows students to investigate and discuss interconnections among apparently…

  9. Geospace Exploration: ERG project

    NASA Astrophysics Data System (ADS)

    Miyoshi, Yoshizumi; Kasaba, Yasumasa; Shiokawa, Kazuo; Hirahara, Masafumi; Nagatsuma, Tsutomu; Takashima, Takeshi; Seki, Kanako; Kumamoto, Atsushi; Asamura, Kazushi; Kojima, Hirotsugu; Ono, DTakayuki; Matsuoka, Ayako; Fujimoto, Masaki

    2012-07-01

    The ERG (Energization and Radiation in Geospace) is a geospace exploration mission in Japan for the solar maximum and subsequent declining phase of solar cycle 24. The mission is especially focusing on the relativistic electron acceleration mechanism in the context of the cross-energy coupling via wave-particle interactions as well as the dynamics of space storms. The interplay among different plasma/particle populations of the inner magnetosphere; plasmasphere, ring current/plasma sheet, and radiation belts is a key to understand the energetic particle accelerations. The cross-regional coupling such as magnetosphere-ionosphere via FAC and the potential electric fields causes the spontaneous variations of the ambient fields. The ERG project consists of the satellite observation team, the ground-based observation team, and integrated-data analysis/simulation team, as well as the science working team and the project science team. The SPRINT-B/ERG satellite of ISAS/JAXA will be launched into inner magnetosphere in FY2014-2015. The comprehensive instruments for plasma/particles, field and waves are installed in the SPRING-B/ERG satellite to elucidate the electron acceleration processes. The newly developed system will directly measure the flow of the Poynting flux between particles and waves in the wave-particle interactions. The Japanese ground-network teams including magnetometer, SuperDARN radar, optical imager, VLF, etc. join the ERG project, which are very powerful tool for geospace remote sensing. The integrated data analysis and simulation team is now developing the simulation tools which can be compared directly with the observations. In this talk, we will present the current status of the ERG project and possible collaborations with other geospace satellite missions such as THEMIS, RBSP and RESONANCE etc. as well as the ground-based observations and simulation studies.

  10. Exploration Update

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Delores Beasley, NASA Public Affairs, introduces the panel who consist of: Scott "Doc" Horowitz, Associate Administrator of Exploration Systems from NASA Headquarters; Jeff Henley, Constellation Program Manager from NASA Johnson Space Flight Center; and Steve Cook, Manager Exploration Launch Office at NASA Marshall Space Flight Center. Scott Horowitz presents a short video entitled, "Ares Launching the Future". He further explains how NASA personnel came up with the name of Ares and where the name Ares was derived. Jeff Henley, updates the Constellation program and Steve Cook presents two slide presentations detailing the Ares l crew launch vehicle and Ares 5 cargo launch vehicle. A short question and answer period from the news media follows.

  11. Space Exploration

    NASA Technical Reports Server (NTRS)

    Davis, Jeffrey R.

    2006-01-01

    This abstract covers a one hour presentation on Space Exploration. The audience is elementary students; therefore there are few words on the slides, mostly pictures of living and working in space. The presentation opens with a few slides describing a day in the life of a space explorer. It begins with a launch, discussions of day-night cycles, eating, exercising, housekeeping, EVA, relaxation, and sleeping. The next section of the presentation shows photos of astronauts performing experiments on the ISS. Yokomi Elementary School launched this fall with the most advanced educational technology tools available in schools today. The science and technology magnet school is equipped with interactive white boards, digital projectors, integrated sound systems and several computers for use by teachers and students. The only elementary school in Fresno Unified with a science focus also houses dedicated science classrooms equipped specifically for elementary students to experience hands-on science instruction in addition to the regular elementary curriculum.

  12. Particle generator

    DOEpatents

    Hess, Wayne P.; Joly, Alan G.; Gerrity, Daniel P.; Beck, Kenneth M.; Sushko, Peter V.; Shlyuger, Alexander L.

    2005-06-28

    Energy tunable solid state sources of neutral particles are described. In a disclosed embodiment, a halogen particle source includes a solid halide sample, a photon source positioned to deliver photons to a surface of the halide, and a collimating means positioned to accept a spatially defined plume of hyperthermal halogen particles emitted from the sample surface.

  13. Alpha Particle

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Term that is sometimes used to describe a helium nucleus, a positively charged particle that consists of two protons and two neutrons, bound together. Alpha particles, which were discovered by Ernest Rutherford (1871-1937) in 1898, are emitted by atomic nuclei that are undergoing alpha radioactivity. During this process, an unstable heavy nucleus spontaneously emits an alpha particle and transmut...

  14. Dynamics explorer guest investigator

    NASA Technical Reports Server (NTRS)

    Sojka, J. J.

    1985-01-01

    The use of Dynamics Explorer (DE) data sets to model the auroral inputs for the time dependent ionospheric model (TDIM) is reported. The modelling requires DE-1 SAI images and simultaneous DE-2 LAPI particle data. The data sets allow the large scale relative auroral variations and local absolute energy flexes and characteristics energies to be defined. The images enabled global scale auroral modelling with 12 min. time resolution and the LAPI data presented a detailed energy flux and characteristic energy calibration of the image model. The auroral model is used as an input to the TDIM and studies ionospheric storms.

  15. Unstable particles near threshold

    NASA Astrophysics Data System (ADS)

    Chway, Dongjin; Jung, Tae Hyun; Kim, Hyung Do

    2016-07-01

    We explore the physics of unstable particles when the mother particle's mass is approximately the sum of the masses of its daughter particles. In this case, the conventional wave function renormalization factor used for the narrow width approximation is ill-defined. We propose a simple resolution of the problem that allows the use of the narrow width approximation by defining the wave function renormalization factor and the branching ratio in terms of the spectral density. We test new definitions by calculating the cross section in the Higgs portal model and a significant improvement is obtained. Meanwhile, no single decay width can be assigned to the unstable particles and non-exponential decay occurs at all time scales.

  16. Exploring Science Through Polar Exploration

    NASA Astrophysics Data System (ADS)

    Pfirman, S. L.; Bell, R. E.; Zadoff, L.; Kelsey, R.

    2003-12-01

    Exploring the Poles is a First Year Seminar course taught at Barnard College, Columbia University. First Year Seminars are required of incoming students and are designed to encourage critical analysis in a small class setting with focused discussion. The class links historical polar exploration with current research in order to: introduce non-scientists to the value of environmental science through polar literature; discuss issues related to venturing into the unknown that are of relevance to any discipline: self-reliance, leadership, preparation, decisions under uncertainty; show students the human face of science; change attitudes about science and scientists; use data to engage students in exploring/understanding the environment and help them learn to draw conclusions from data; integrate research and education. These goals are met by bringing analysis of early exploration efforts together with a modern understanding of the polar environment. To date to class has followed the efforts of Nansen in the Fram, Scott and Amundsen in their race to the pole, and Shackleton's Endurance. As students read turn-of-the-century expedition journals, expedition progress is progressively revealed on an interactive map showing the environmental context. To bring the exploration process to life, students are assigned to expedition teams for specific years and the fates of the student "expeditions" are based on their own decisions. For example, in the Arctic, they navigate coastal sea ice and become frozen into the ice north of Siberia, re-creating Nansen's polar drift. Fates of the teams varied tremendously: some safely emerged at Fram Strait in 4 years, while others nearly became hopelessly lost in the Beaufort Gyre. Students thus learn about variability in the current polar environment through first hand experience, enabling them to appreciate the experiences, decisions, and, in some cases, the luck, of polar explorers. Evaluation by the Columbia Center for New Media, Teaching

  17. Particle Detectors

    NASA Astrophysics Data System (ADS)

    Grupen, Claus; Shwartz, Boris

    2011-09-01

    Preface to the first edition; Preface to the second edition; Introduction; 1. Interactions of particles and radiation with matter; 2. Characteristic properties of detectors; 3. Units of radiation measurements and radiation sources; 4. Accelerators; 5. Main physical phenomena used for particle detection and basic counter types; 6. Historical track detectors; 7. Track detectors; 8. Calorimetry; 9. Particle identification; 10. Neutrino detectors; 11. Momentum measurement and muon detection; 12. Ageing and radiation effects; 13. Example of a general-purpose detector: Belle; 14. Electronics; 15. Data analysis; 16. Applications of particle detectors outside particle physics; 17. Glossary; 18. Solutions; 19. Resumé; Appendixes; Index.

  18. Geochemical Exploration of the Moon.

    ERIC Educational Resources Information Center

    Adler, Isidore

    1984-01-01

    Provides information based on explorations of the Apollo program about the geochemistry of the moon and its importance in developing an understanding of formation/evolution of the solar system. Includes description and some results of orbital remote sensing, lunar x-ray experiments, gamma-ray experiments, alpha-particle experiments, and the Apollo…

  19. Space Earthquake Perturbation Simulation (SEPS) an application based on Geant4 tools to model and simulate the interaction between the Earthquake and the particle trapped on the Van Allen belt

    NASA Astrophysics Data System (ADS)

    Ambroglini, Filippo; Jerome Burger, William; Battiston, Roberto; Vitale, Vincenzo; Zhang, Yu

    2014-05-01

    During last decades, few space experiments revealed anomalous bursts of charged particles, mainly electrons with energy larger than few MeV. A possible source of these bursts are the low-frequency seismo-electromagnetic emissions, which can cause the precipitation of the electrons from the lower boundary of their inner belt. Studies of these bursts reported also a short-term pre-seismic excess. Starting from simulation tools traditionally used on high energy physics we developed a dedicated application SEPS (Space Perturbation Earthquake Simulation), based on the Geant4 tool and PLANETOCOSMICS program, able to model and simulate the electromagnetic interaction between the earthquake and the particles trapped in the inner Van Allen belt. With SEPS one can study the transport of particles trapped in the Van Allen belts through the Earth's magnetic field also taking into account possible interactions with the Earth's atmosphere. SEPS provides the possibility of: testing different models of interaction between electromagnetic waves and trapped particles, defining the mechanism of interaction as also shaping the area in which this takes place,assessing the effects of perturbations in the magnetic field on the particles path, performing back-tracking analysis and also modelling the interaction with electric fields. SEPS is in advanced development stage, so that it could be already exploited to test in details the results of correlation analysis between particle bursts and earthquakes based on NOAA and SAMPEX data. The test was performed both with a full simulation analysis, (tracing from the position of the earthquake and going to see if there were paths compatible with the burst revealed) and with a back-tracking analysis (tracing from the burst detection point and checking the compatibility with the position of associated earthquake).

  20. Geoelectrical exploration

    NASA Astrophysics Data System (ADS)

    Barseem, Mostafa Said; El Lateef, Talaat Ali Abd; Ezz El Deen, Hosny Mahomud; Abdel Rahman, Abd Allah Al Abaseiry

    2015-12-01

    Sinai development is a goal of successive governments in Egypt. The present study is a geoelectrical exploration to find appropriate solutions of the problems affecting the land of a Research Station in Southeast Al Qantara. This research station is one of the Desert Research Center stations to facilitate the development of desert land for agriculture by introducing applied research. It suffers from some problems which can be summarized in the shortage of irrigation water and water logging. The appropriate solutions of these problems have been delineated by the results of 1D and 2D geoelectrical measurements. Electrical resistivity (ER) revealed the subsurface sedimentary sequences and extension of subsurface layers in the horizontal and vertical directions, especially, the water bearing layer. Additionally it helped to choose the most suitable places to drill productive wells with a good condition.

  1. Particle astrophysics

    NASA Technical Reports Server (NTRS)

    Sadoulet, Bernard; Cronin, James; Aprile, Elena; Barish, Barry C.; Beier, Eugene W.; Brandenberger, Robert; Cabrera, Blas; Caldwell, David; Cassiday, George; Cline, David B.

    1991-01-01

    The following scientific areas are reviewed: (1) cosmology and particle physics (particle physics and the early universe, dark matter, and other relics); (2) stellar physics and particles (solar neutrinos, supernovae, and unconventional particle physics); (3) high energy gamma ray and neutrino astronomy; (4) cosmic rays (space and ground observations). Highest scientific priorities for the next decade include implementation of the current program, new initiatives, and longer-term programs. Essential technological developments, such as cryogenic detectors of particles, new solar neutrino techniques, and new extensive air shower detectors, are discussed. Also a certain number of institutional issues (the funding of particle astrophysics, recommended funding mechanisms, recommended facilities, international collaborations, and education and technology) which will become critical in the coming decade are presented.

  2. Particle therapy

    SciTech Connect

    Raju, M.R.

    1993-09-01

    Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics.

  3. Particle astrophysics

    NASA Astrophysics Data System (ADS)

    Sadoulet, Bernard; Cronin, James; Aprile, Elena; Barish, Barry C.; Beier, Eugene W.; Brandenberger, Robert; Cabrera, Blas; Caldwell, David; Cassiday, George; Cline, David B.

    The following scientific areas are reviewed: (1) cosmology and particle physics (particle physics and the early universe, dark matter, and other relics); (2) stellar physics and particles (solar neutrinos, supernovae, and unconventional particle physics); (3) high energy gamma ray and neutrino astronomy; (4) cosmic rays (space and ground observations). Highest scientific priorities for the next decade include implementation of the current program, new initiatives, and longer-term programs. Essential technological developments, such as cryogenic detectors of particles, new solar neutrino techniques, and new extensive air shower detectors, are discussed. Also a certain number of institutional issues (the funding of particle astrophysics, recommended funding mechanisms, recommended facilities, international collaborations, and education and technology) which will become critical in the coming decade are presented.

  4. Magnetic particles

    NASA Technical Reports Server (NTRS)

    Chang, Manchium (Inventor); Colvin, Michael S. (Inventor)

    1989-01-01

    Magnetic polymer particles are formed by swelling porous, polymer particles and impregnating the particles with an aqueous solution of precursor magnetic metal salt such as an equimolar mixture of ferrous chloride and ferric chloride. On addition of a basic reagent such as dilute sodium hydroxide, the metal salts are converted to crystals of magnetite which are uniformly contained througout the pores of the polymer particle. The magnetite content can be increased and neutral buoyancy achieved by repetition of the impregnaton and neutralization steps to adjust the magnetite content to a desired level.

  5. Dynamics Explorer guest investigator

    NASA Technical Reports Server (NTRS)

    Sojka, Jan J.

    1991-01-01

    A data base of satellite particle, electric field, image, and plasma data was used to determine correlations between the fields and the particle auroral boundaries. A data base of 8 days of excellent coverage from all instruments was completed. The geomagnetic conditions associated with each of the selected data periods, the number of UV image passes per study day that were obtained, and the total number of UV images for each day are given in tabular form. For each of the days listed in Table 1, both Vector Electric Field Instrument (VEFI) electric potential data and LAPI integrated particle energy fluxes were obtained. On the average, between 8 and 11 passes of useful data per day were obtained. These data are displayed in a format such that either the statistical electric field model potential or the statistical precipitation energy flux could be superimposed. The Heppner and Maynard (1987) and Hardy et al. (1987) models were used for the electric potential and precipitation, respectively. In addition, the auroral image intensity along the Dynamics Explorer-2 satellite pass could be computed and plotted along with the LAPI precipitation data and Hardy et al. (1987) values.

  6. [Exploring Aeronautics

    NASA Technical Reports Server (NTRS)

    Robinson, Brandi

    2004-01-01

    This summer I have been working with the N.A.S.A. Project at Cuyahoga Community College (Tri-C) under the title of Exploring Aeronautics Project Leader. The class that I have worked with is comprised of students that will enter the eighth grade in the fall of 2004. The program primarily focuses upon math proficiency and individualized class projects. My duties have encompassed both realms. During the first 2-3 weeks of my internship, I worked at NASA Glenn Research Center (GRC) researching, organizing, and compiling information for weekly Scholastic Challenges and the Super Scholastic Challenge. I was able to complete an overview of Scholastic Challenge and staff responsibilities regarding the competition; a proposal for an interactive learning system, Quizdom; a schedule for challenge equipment, as well as a schedule listing submission deadlines for the staff. Also included in my tasks, during these first 2-3 weeks, were assisting Tammy Allen and Candice Thomas with the student application review and interview processes for student applicants. For the student and parent orientation, I was assigned publications and other varying tasks to complete before the start of the program. Upon the commencement of the program, I changed location from NASA GRC to Tri-C Metro Campus, where student classes for the Cleveland site are held. During the duration of the program, I work with the instructor for the Exploring Aeronautics class, kkkk, assisting in classroom management, daily attendance, curriculum, project building, and other tasks as needed. These tasks include the conducting of the weekly competition, known as Scholastic Challenge. As a Project Leader, I am also responsible for one subject area of the Scholastic Challenge aspect of the N.A.S.A. Project curriculum. Each week I have to prepare a mission that the participants will take home the following Monday and at least 10 questions that will be included in the pool of questions used for the Scholastic Challenge

  7. Project Explorer

    NASA Technical Reports Server (NTRS)

    Dannenberg, K. K.; Henderson, A.; Lee, J.; Smith, G.; Stluka, E.

    1984-01-01

    PROJECT EXPLORER is a program that will fly student-developed experiments onboard the Space Shuttle in NASA's Get-Away Special (GAS) containers. The program is co-sponsored by the Alabama Space and Rocket Center, the Alabama-Mississippi Section of the American Institute of Aeronautics and Astronautics, Alabama A&M University and requires extensive support by the University of Alabama in Huntsville. A unique feature of this project will demonstrate transmissions to ground stations on amateur radio frequencies in English language. Experiments Nos. 1, 2, and 3 use the microgravity of space flight to study the solidification of lead-antimony and aluminum-copper alloys, the growth of potassium-tetracyanoplatinate hydrate crystals in an aqueous solution, and the germination of radish seeds. Flight results will be compared with Earth-based data. Experiment No. 4 features radio transmission and will also provide timing for the start of all other experiments. A microprocessor will obtain real-time data from all experiments as well as temperature and pressure measurements taken inside the canister. These data will be transmitted on previously announced amateur radio frequencies after they have been converted into the English language by a digitalker for general reception.

  8. The Nuclear Astrophysics Explorer

    NASA Technical Reports Server (NTRS)

    Matteson, J. L.; Teegarden, B. J.; Gehrels, N.; Mahoney, W. A.

    1989-01-01

    The Nuclear Astrophysics Explorer was proposed in 1986 for NASA's Explorer Concept Study Program by an international collaboration of 25 scientists from nine institutions. The one-year feasibility study began in June 1988. The Nuclear Astrophysics Explorer would obtain high resolution observations of gamma-ray lines, E/Delta E about 1000, at a sensitivity of about 0.000003 ph/sq cm s, in order to study fundamental problems in astrophysics such as nucleosynthesis, supernovae, neutron star and black-hole physics, and particle acceleration and interactions. The instrument would operate from 15 keV to 10 Mev and use a heavily shielded array of nine cooled Ge spectrometers in a very low background configuration. Its 10 deg FWHM field of view would contain a versatile coded mask system which would provide two-dimensional imaging with 4 deg resolution, one-dimensional imaging with 2 deg resolution, and efficiendt measurements of diffuse emission. An unshielded Ge spectrometer would obtain wide-field measurements of transient gamma-ray sources. The earliest possible mission would begin in 1995.

  9. Particle preconcentrator

    DOEpatents

    Linker, K.L.; Conrad, F.J.; Custer, C.A.; Rhykerd, C.L. Jr.

    1998-12-29

    An apparatus and method are disclosed for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents. 3 figs.

  10. Particle preconcentrator

    SciTech Connect

    Linker, K.L.; Conrad, F.J.; Custer, C.A.; Rhykerd, C.L. Jr

    2000-07-11

    An apparatus and method are disclosed for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a previous screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  11. Particle preconcentrator

    SciTech Connect

    Linker, Kevin L.; Conrad, Frank J.; Custer, Chad A.; Rhykerd, Jr., Charles L.

    1998-01-01

    An apparatus and method for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  12. Particle preconcentrator

    SciTech Connect

    Linker, Kevin L.; Conrad, Frank J.; Custer, Chad A.; Rhykerd, Jr., Charles L.

    2005-09-20

    An apparatus and method for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  13. Particle preconcentrator

    SciTech Connect

    Linker, Kevin L.; Conrad, Frank J.; Custer, Chad A.; Rhykerd, Jr., Charles L.

    2000-01-01

    An apparatus and method for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  14. Exploring Quarks, Gluons and the Higgs Boson

    ERIC Educational Resources Information Center

    Johansson, K. Erik

    2013-01-01

    With real particle collision data available on the web, the amazing dynamics of the fundamental particles of the standard model can be explored in classrooms. Complementing the events from the ATLAS experiment with animations of the fundamental processes on the quark and gluon level makes it possible to better understand the invisible world of…

  15. Detectors for Particle Radiation

    NASA Astrophysics Data System (ADS)

    Kleinknecht, Konrad

    1999-01-01

    This textbook provides a clear, concise and comprehensive review of the physical principles behind the devices used to detect charged particles and gamma rays, and the construction and performance of these many different types of detectors. Detectors for high-energy particles and radiation are used in many areas of science, especially particle physics and nuclear physics experiments, nuclear medicine, cosmic ray measurements, space sciences and geological exploration. This second edition includes all the latest developments in detector technology, including several new chapters covering micro-strip gas chambers, silicion strip detectors and CCDs, scintillating fibers, shower detectors using noble liquid gases, and compensating calorimeters for hadronic showers. This well-illustrated textbook contains examples from the many areas in science in which these detectors are used. It provides both a coursebook for students in physics, and a useful introduction for researchers in other fields.

  16. Exploring Mars

    NASA Astrophysics Data System (ADS)

    Breuil, Stéphanie

    2016-04-01

    Mars is our neighbour planet and has always fascinated humans as it has been seen as a potential abode for life. Knowledge about Mars is huge and was constructed step by step through numerous missions. It could be difficult to describe these missions, the associated technology, the results, the questions they raise, that's why an activity is proposed, that directly interests students. Their production is presented in the poster. Step 1: The main Mars feature and the first Mars explorations using telescope are presented to students. It should be really interesting to present "Mars Canals" from Percival Lowell as it should also warn students against flawed interpretation. Moreover, this study has raised the big question about extra-terrestrial life on Mars for the first time. Using Google Mars is then a good way to show the huge knowledge we have on the planet and to introduce modern missions. Step 2: Students have to choose and describe one of the Mars mission from ESA and NASA. They should work in pairs. Web sites from ESA and NASA are available and the teacher makes sure the main missions will be studied. Step 3: Students have to collect different pieces of information about the mission - When? Which technology? What were the main results? What type of questions does it raise? They prepare an oral presentation in the form they want (role play, academic presentation, using a poster, PowerPoint). They also have to produce playing cards about the mission that could be put on a timeline. Step 4: As a conclusion, the different cards concerning different missions are mixed. Groups of students receive cards and they have to put them on a timeline as fast as possible. It is also possible to play the game "timeline".

  17. Geotail mission to explore earth's magnetotail

    NASA Astrophysics Data System (ADS)

    Nishida, A.; Uesugi, K.; Nakatani, I.; Mukai, T.; Fairfield, D. H.; Acuna, M. H.

    1992-10-01

    The Geotail satellite mission is a cooperative venture of NASA and ISAS of Japan for exploration of the magnetotail region of the earth's magnetosphere. Geotail will deepen understanding into fundamental processes, such as those of energy transfer from the solar wind to the magnetosphere, magnetotail particle acceleration, tail energy release onset, the transport of particles between the tail and the inner magnetosphere, the bow shock, and wave-particle interactions. Attention is given to both Geotail spacecraft and mission design.

  18. Elementary particles

    NASA Astrophysics Data System (ADS)

    Fritzsch, Harald; Heusch, Karin

    Introduction -- Electrons and atomic nuclei -- Quantum properties of atoms and particles -- The knives of Democritus -- Quarks inside atomic nuclei -- Quantum electrodynamics -- Quantum chromodynamics -- Mesons, baryons, and quarks -- Electroweak interactions -- Grand unification -- Conclusion.

  19. Magnetic particles

    NASA Technical Reports Server (NTRS)

    Chang, Manchium (Inventor); Colvin, Michael S. (Inventor); Rembaum, Alan (Inventor); Richards, Gil F. (Inventor)

    1987-01-01

    Metal oxide containing polymers and particularly styrene, acrylic or protein polymers containing fine, magnetic iron oxide particles are formed by combining a NO.sub.2 -substituted polymer with an acid such as hydrochloric acid in the presence of metal, particularly iron particles. The iron is oxidized to fine, black Fe.sub.3 O.sub.4 particles which deposit selectively on the polymer particles. Nitrated polymers are formed by reacting functionally substituted, nitrated organic compounds such as trinitrobenzene sulfonate or dinitrofluoro benzene with a functionally coreactive polymer such as an amine modified acrylic polymer or a protein. Other transition metals such as cobalt can also be incorporated into polymers using this method.

  20. Elementary Particles

    ERIC Educational Resources Information Center

    Parham, R.

    1974-01-01

    Presents the text of a speech given to a conference of physics teachers in which the full spectrum of elementary particles is given, along with their classification. Also includes some teaching materials available on this topic. (PEB)

  1. Auroral particles

    NASA Technical Reports Server (NTRS)

    Evans, David S.

    1987-01-01

    The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries.

  2. MESSENGER: Exploring Mercury's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Slavin, James A.

    2008-01-01

    The MESSENGER mission to Mercury offers our first opportunity to explore this planet's miniature magnetosphere since Mariner 10's brief fly-bys in 1974-5. Mercury's magnetosphere is unique in many respects. The magnetosphere of Mercury is the smallest in the solar system with its magnetic field typically standing off the solar wind only - 1000 to 2000 km above the surface. For this reason there are no closed dri-fi paths for energetic particles and, hence, no radiation belts; the characteristic time scales for wave propagation and convective transport are short possibly coupling kinetic and fluid modes; magnetic reconnection at the dayside magnetopause may erode the subsolar magnetosphere allowing solar wind ions to directly impact the dayside regolith; inductive currents in Mercury's interior should act to modify the solar In addition, Mercury's magnetosphere is the only one with its defining magnetic flux tubes rooted in a planetary regolith as opposed to an atmosphere with a conductive ionosphere. This lack of an ionosphere is thought to be the underlying reason for the brevity of the very intense, but short lived, approx. 1-2 min, substorm-like energetic particle events observed by Mariner 10 in Mercury's magnetic tail. In this seminar, we review what we think we know about Mercury's magnetosphere and describe the MESSENGER science team's strategy for obtaining answers to the outstanding science questions surrounding the interaction of the solar wind with Mercury and its small, but dynamic magnetosphere.

  3. Halloween 2003 Solar Storm and the Effects on Earth's Radiation Belts

    NASA Video Gallery

    This scientific visualization relies on data from the SAMPEX mission, which observed particles in the Radiation Belts during a large solar storm in October 2003. The movie clearly shows just how mu...

  4. Multiswarm Particle Swarm Optimization with Transfer of the Best Particle

    PubMed Central

    Wei, Xiao-peng; Zhang, Jian-xia; Zhou, Dong-sheng; Zhang, Qiang

    2015-01-01

    We propose an improved algorithm, for a multiswarm particle swarm optimization with transfer of the best particle called BMPSO. In the proposed algorithm, we introduce parasitism into the standard particle swarm algorithm (PSO) in order to balance exploration and exploitation, as well as enhancing the capacity for global search to solve nonlinear optimization problems. First, the best particle guides other particles to prevent them from being trapped by local optima. We provide a detailed description of BMPSO. We also present a diversity analysis of the proposed BMPSO, which is explained based on the Sphere function. Finally, we tested the performance of the proposed algorithm with six standard test functions and an engineering problem. Compared with some other algorithms, the results showed that the proposed BMPSO performed better when applied to the test functions and the engineering problem. Furthermore, the proposed BMPSO can be applied to other nonlinear optimization problems. PMID:26345200

  5. Instrumentation for interstellar exploration

    NASA Astrophysics Data System (ADS)

    Gruntman, M.

    The time has arrived for designing, building, and instrumenting a spacecraft for a dedicated foray into interstellar space surrounding our star, the Sun. This region was probed in the past by remote techniques and it will be explored in situ by the Interstellar Probe mission. The mission will significantly advance our understanding of the nature of the local interstellar medium and explore the distant frontier of the solar system by revealing the details of the interaction between the Sun and Galaxy. This mission will also be an important practical step toward interstellar flight of the future. Reaching interstellar space in reasonable time requires high escape velocities and will likely be enabled by non-chemical propulsion such as nuclear-powered electric propulsion or solar sailing. Unusually high spacecraft velocities, enormous distances from the Sun, and non-chemical propulsion will significantly influence the design of the mission, spacecraft and scientific instrumentation. We will review measurement objectives of the first mission into interstellar space and outline constrains on the instrumentation. Measurement of particles, fields, and dust in the interstellar medium will be complemented by search for complex molecules and remote sensing capabilities in various spectral bands. A "look" back at our solar system will also be a glimpse of wh at a flyby mission of the distant future would encounter in approaching another star. The instrumentation for interstellar exploration presents numerous challenges. Mass, telemetry, and power constraints would place a premium on miniaturization and autonom . There are, however,y physical limits on how small the sensors could be. New instrument concepts may be required to achieve the desired measurement capabilities under the stringent constraints of a realistic interstellar mission.

  6. Instrumentation for interstellar exploration

    NASA Astrophysics Data System (ADS)

    Gruntman, Mike

    2004-01-01

    The time has arrived for designing, building, and instrumenting a spacecraft for a dedicated foray into the galactic environment surrounding our star, the sun. This region was probed in the past by remote techniques and it will be explored in situ by the NASA's planned Interstellar Probe mission. The mission will significantly advance our understanding of the nature of the local interstellar medium and explore the distant frontier of the solar system by revealing the details of the interaction between the sun and the Galaxy. This mission will also be an important practical step toward interstellar flight of the future. Reaching interstellar space in reasonable time requires high escape velocities and will likely be enabled by non-chemical propulsion such as nuclear-powered electric propulsion or solar sailing. Unusually high spacecraft velocities, enormous distances from the Sun, and non-chemical propulsion will significantly influence design of the mission, spacecraft, and scientific instrumentation. We will review measurement objectives of the first dedicated mission into interstellar space and outline constraints on the instrumentation. Measurement of particles, fields, and dust in the interstellar medium will be complemented by search for complex organic molecules and remote sensing capabilities in various spectral bands. A "look" back at our solar system will also be a glimpse of what a truly-interstellar mission of the distant future would encounter in approaching a target star. The instrumentation for interstellar exploration presents numerous challenges. Mass, telemetry, and power constraints would place a premium on miniaturization and autonomy. There are, however, physical limits on how small the sensors could be. New instrument concepts may be required to achieve the desired measurement capabilities under the stringent constraints of a realistic interstellar mission.

  7. The return of the anomalous cosmic rays to 1 Au in 1992

    NASA Technical Reports Server (NTRS)

    Mewaldt, R. A.; Cummings, A. C.; Cummings, J. R.; Stone, E. C.; Klecker, B.; Hovestadt, D.; Scholer, M.; Mason, G. M.; Mazur, J. E.; Hamilton, D. C.

    1993-01-01

    New observations of low energy (approximately 1 to 200 MeV/nuc) cosmic rays measured by three newly launched experiments on Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) during 1992 and 1993 show the strong presence of anomalous cosmic ray (ACR) nitrogen and oxygen, well before the approaching solar minimum. When compared with ACR temporal variations over the past two solar cycles we find that the 1992-1993 fluxes are approximately 5 to 10 times their level at corresponding neutron monitor counting rates in 1969-1970 and 1985.

  8. Particle Sizer

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Microspheres are tiny plastic beads that represent the first commercial products manufactured in orbit. An example of how they are used is a new aerodynamic particle sizer designated APS 33B produced by TSI Incorporated. TSI purchased the microspheres from the National Bureau of Standards which certified their exact size and the company uses them in calibration of the APS 33B* instrument, latest in a line of TSI systems for generating counting and weighing minute particles of submicron size. Instruments are used for evaluating air pollution control devices, quantifying environments, meteorological research, testing filters, inhalation, toxicology and other areas where generation or analysis of small airborne particles is required. * The APS 33B is no longer being manufactured. An improved version, APS 3320, is now being manufactured. 2/28/97

  9. Carbon particles

    DOEpatents

    Hunt, Arlon J.

    1984-01-01

    A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

  10. Explosive formation of coherent particle jets

    NASA Astrophysics Data System (ADS)

    Frost, David; Ruel, Jean-Frederic; Zarei, Zouya; Goroshin, Sam; Gregoire, Yann; Zhang, Fan; Milne, Alec; Longbottom, Aaron

    2013-06-01

    A high-speed jet of solid particles may be formed by detonating an explosive layer lining the outside of a conically-shaped volume of particles. Experiments have been carried out to determine the velocity history and the coherency of a particle jet formed using this shaped-charge arrangement. Important parameters include the cone angle, the ratio of the masses of the explosive and particles, and the particle size and density. Dense particles (e.g., iron) form thin, stable, coherent jets, whereas lighter particles (e.g., glass or Al) lead to more diffuse jets. The jet velocities observed experimentally were close to the predictions from a Gurney velocity formulation for conical geometry. The effects of cone angle and particle density on the jet formation and development were explored with calculations using a multimaterial hydrocode. The simulations indicate that the converging shock and Mach disk within the particle bed have a strong influence on the uniformity of the particle density field. With iron particles, the particle volume remains coherent whereas for glass particles, during the particle acceleration phase, the shock interactions within the particle bed cause the particles to be concentrated in a thin shell surrounding a low density region.

  11. Particle blender

    DOEpatents

    Willey, Melvin G.

    1981-01-01

    An infinite blender that achieves a homogeneous mixture of fuel microspheres is provided. Blending is accomplished by directing respective groups of desired particles onto the apex of a stationary coaxial cone. The particles progress downward over the cone surface and deposit in a space at the base of the cone that is described by a flexible band provided with a wide portion traversing and in continuous contact with the circumference of the cone base and extending upwardly therefrom. The band, being attached to the cone at a narrow inner end thereof, causes the cone to rotate on its arbor when the band is subsequently pulled onto a take-up spool. As a point at the end of the wide portion of the band passes the point where it is tangent to the cone, the blended particles are released into a delivery tube leading directly into a mold, and a plate mounted on the lower portion of the cone and positioned between the end of the wide portion of the band and the cone assures release of the particles only at the tangent point.

  12. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

    ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

  13. Particle astrophysics

    SciTech Connect

    Sadoulet, B. |

    1992-12-31

    In the last few years, particle astrophysics has emerged as a new field at the frontier between high energy astrophysics, cosmology, and particle physics. Two spectacular achievements of this new field in the last decade have been the establishment of neutrino astronomy with the detection of solar neutrinos by two independent experiments and the spectacular observation of the neutrinos from the supernova SN1987A. In addition, the field has produced tantalizing hints of new physics beyond the standard models of astrophysics and particle physics, generating enthusiastic attempts to confirm these potential effects. This new field involves some two hundred experimentalists and a similar number of theorists, most of them coming from particle and nuclear physics, and as scientist will see, their effort is to a large extent complementary to accelerator based high energy physics. This review attempts, at the beginning of this workshop, to capture the excitement of this new field. Summary talks will describe in more detail some of the topics discussed in the study groups.

  14. Minimal relativistic three-particle equations

    SciTech Connect

    Lindesay, J.

    1981-07-01

    A minimal self-consistent set of covariant and unitary three-particle equations is presented. Numerical results are obtained for three-particle bound states, elastic scattering and rearrangement of bound pairs with a third particle, and amplitudes for breakup into states of three free particles. The mathematical form of the three-particle bound state equations is explored; constraints are set upon the range of eigenvalues and number of eigenstates of these one parameter equations. The behavior of the number of eigenstates as the two-body binding energy decreases to zero in a covariant context generalizes results previously obtained non-relativistically by V. Efimov.

  15. Astrobiology and Venus exploration

    NASA Astrophysics Data System (ADS)

    Grinspoon, David H.; Bullock, Mark A.

    life. Life, once established in the early oceans of Venus, may have migrated to the clouds which, on present day Venus, may represent a habitable niche. Though highly acidic, this aqueous environment enjoys moderate temperatures, surroundings far from chemical equilibrium, and potentially useful radiation fluxes. Observations of unusual chemistry in the clouds, and particle populations that are not well characterized, suggest that this environment must be explored much more fully before biology can be ruled out. A sulfur-based metabolism for cloud-based life on Venus has recently been proposed (Schulze-Makuch et al., 2004). While speculative, these arguments, along with the discovery of terrestrial extremophile organisms that point toward the plausibility of survival in the Venusian clouds, establish the credibility of astrobiological exploration of Venus. Arguments for the possible existence of life on Mars or Europa are, by convention and repetition, seen as more mainstream than arguments for life elsewhere, but their logical status is similar to plausibility arguments for life on Venus. With the launch of COROT in 2006 and Kepler in 2008 the demographics of Earth-sized planets in our galaxy should finally become known. Future plans for a Terrestrial Planet Finder or Darwin-type space-based spectrograph should provide the capability of studying the atmospheric composition and other properties of terrestrial planets. One of the prime rationales for building such instruments is the possibility of identifying habitable planets or providing more generalized observational constraints on the habitable zones of stellar systems. Given the prevalence of CO2 dominated atmospheres in our own solar system, it is quite likely that a large fraction of these will be Venus-like in composition and evolutionary history. We will be observing these planets at random times in their evolution. In analogy with our own solar system, it is just as likely that we will find representatives of

  16. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  17. PET - A proton/electron telescope for studies of magnetospheric, solar, and galactic particles

    NASA Technical Reports Server (NTRS)

    Cook, Walter R.; Cummings, Alan C.; Cummings, Jay R.; Garrard, Thomas L.; Kecman, Branislav; Mewaldt, Richard A.; Selesnick, Richard S.; Stone, Edward C.; Baker, Daniel N.; Von Rosenvinge, Tycho T.

    1993-01-01

    The Proton/Electron Telescope (PET) on SAMPEX is designed to provide measurements of energetic electrons and light nuclei from solar, galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from about 1 to about 30 MeV and H and He nuclei from about 20 to about 300 MeV/nuc, with isotope resolution of H and He extending from about 20 to about 80 MeV/nuc. As SAMPEX scans all local times and geomagnetic cutoffs over the course of its near-polar orbit, PET will characterize precipitating relativistic electron events during periods of declining solar activity, and it will examine whether the production rate of odd nitrogen and hydrogen molecules in the middle atmosphere by precipitating electrons is sufficient to affect O3 depletion. In addition, PET will complement studies of the elemental and isotopic composition of energetic heavy (Z greater than 2) nuclei on SAMPEX by providing measurements of H, He, and electrons. Finally, PET has limited capability to identify energetic positrons from potential natural and man-made sources.

  18. Exploring the Universe.

    ERIC Educational Resources Information Center

    Aviation/Space, 1982

    1982-01-01

    Highlights National Aeronautics and Space Administration's (NASA) space exploration studies, focusing on Voyager at Saturn, advanced Jupiter exploration, infrared observatory, space telescope, Dynamics Explorers (satellites designed to provide understanding of earth/sun energy relationship), and ozone studies. (JN)

  19. Exploration Technology Development & Demonstration

    NASA Video Gallery

    Chris Moore delivers a presentation from the Exploration Technology Development & Demonstration (ETDD) study team on May 25, 2010, at the NASA Exploration Enterprise Workshop held in Galveston, TX....

  20. Solar Eruptions and Energetic Particles

    NASA Astrophysics Data System (ADS)

    Gopalswamy, Natchimuthukonar; Mewaldt, Richard; Torsti, Jarmo

    Coronal mass ejections (CMEs) are the most energetic events in the heliosphere. During solar cycle 23, the close connection between CMEs and solar energetic particles (SEPs) was studied in much greater detail than was previously possible, including effects on space weather. This book reviews extensive observations of solar eruptions and SEPs from orbiting and ground-based systems. From SOHO and ACE to RHESSI and TRACE, we now have measurements of unprecedented sensitivity by which to test assumptions and refine models. Discussion and analysis of: • Coronal mass ejections and energetic particles over one solar cycle • Implications of solar eruptions for space weather and human space exploration • The elemental, isotopic, and ionic charge state composition of accelerated particles • Complex interconnections among CMEs, flares, shocks, and energetic particles will make this book an indispensable resource for scientists working on the Sun-Earth connection, including space physicists, magnetospheric physicists, atmospheric physicists, astrophysicists, and aeronomists.

  1. Tumbling in Turbulence: How much does particle shape effect particle motion?

    NASA Astrophysics Data System (ADS)

    Variano, E. A.; Andersson, H. I.; Zhao, L.; Byron, M.

    2014-12-01

    Natural particles suspended in surface water are often non-spherical. We explore the ways in which particle shape effects particle motion, focusing specifically on how particle rotation is divided into spinning and tumbling components. This, in turn, will effect particle collision, clustering, and settling rates. We focus on idealized axisymmetric particles shaped as rods, discs, and spheroids. They are chosen so as to explain the physics of aspherical-particle motion that will be relevant for natural particles such as plankton, sediment, or aggregates (e.g. oil-mineral aggregates, clay flocs, or bio-sediment aggregates held together by TEP). Our work begins with laboratory measurements of particle motion in a turbulence tank built to mimic the flow found in rivers, estuaries, and the ocean surface mixed layer. We then proceed to direct numerical simulation of particle-flow interactions in sheared turbulence similar to that which is found in the surface water of creeks and rivers. We find that shape has only a very weak effect on particle angular velocity, which is a quantity calculated with respect the global reference frame (i.e. east/north/up). If we analyze rotation in a particle's local frame (i.e. the particle's principle axes of rotation), then particle shape has a strong effect on rotation. In the local frame, rotation is described by two components: tumbling and spinning. We find that rod-shaped particles spin more than they tumble, and we find that disc-shaped particles tumble more than they spin. Such behavior is indicative of how particles respond the the directional influence of vortex tubes in turbulence, and such response has implications for particle motion other than rotation. Understanding particle alignment is relevant for predicting particle-particle collision rates, particle-wall collision rates, and the shear-driven breakup of aggregates. We discuss these briefly in the context of what can be concluded from the rotation data discussed above.

  2. Particle Physics

    NASA Astrophysics Data System (ADS)

    Cooper, Necia Grant; West, Geoffrey B.

    1988-06-01

    Preface; Introduction; Part I. Theoretical Framework: 1. Scale and dimension - From animals to quarks Geoffrey B. West; 2. Particle physics and the standard model Stuart Raby, Richard C. Slansky and Geoffrey B. West; QCD on a Cray: the masses of elementary particles Gerald Guralnik, Tony Warnock and Charles Zemach; Lecture Notes - From simple field theories to the standard model; 3. Toward a unified theory: an essay on the role of supergravity in the search for unification Richard C. Slansky; 4. Supersymmetry at 100 GeV Stuart Raby; 5. The family problem T. Goldman and Michael Martin Nieto; Part II. Experimental Developments: 6. Experiments to test unification schemes Gary H. Sanders; 7. The march toward higher energies S. Peter Rosen; LAMPF II and the High-Intensity Frontier Henry A. Thiessen; The SSC - An engineering challenge Mahlon T. Wilson; 8. Science underground - the search for rare events L. M. Simmons, Jr; Part III. Personal Perspectives: 9. Quarks and quirks among friends Peter A. Carruthers, Stuart Raby, Richard C. Slansky, Geoffrey B. West and George Zweig; Index.

  3. Exploring Baryons for Dark Matter

    NASA Astrophysics Data System (ADS)

    Goradia, Shantilal

    There is on-going research for the detection of WIMP's based on a speculative idea of supersymmetry, which attempts to unify the fundamental forces of nature, including gravity. The detection of WIMP's is expected to find a solution to the issue of dark matter. We continue to hold and support our view of the millennium that gravity is not a fundamental force of Nature. We are therefore exploring baryons as the particles to address the issue of dark matter. We poster present our analyses to support our proposal.

  4. Dynamics explorer interdisciplinary scientist investigations

    NASA Technical Reports Server (NTRS)

    Kozyra, Janet U.; Nagy, A. F.

    1994-01-01

    This document is a final report on research activities and accomplishments that occurred during the funding period of 10-1-90 through 1-30-94. The focus of our interdisciplinary investigation during the Dynamics Explorer Mission was on the complex coupling processes that tap the magnetic-storm energy, stored in the ring current particle reservoir, and transport this energy into the subauroral, midlatitude and even equatorial ionospheric regions. The transport of energy through the inner magnetosphere and into the underlying ionospheric regions is a critical element in our understanding of the impact of solar and magnetic disturbances on upper atmospheric and ionospheric regions equatorward of the auroral zone.

  5. Astrobiology and Venus exploration

    NASA Astrophysics Data System (ADS)

    Grinspoon, David H.; Bullock, Mark A.

    life. Life, once established in the early oceans of Venus, may have migrated to the clouds which, on present day Venus, may represent a habitable niche. Though highly acidic, this aqueous environment enjoys moderate temperatures, surroundings far from chemical equilibrium, and potentially useful radiation fluxes. Observations of unusual chemistry in the clouds, and particle populations that are not well characterized, suggest that this environment must be explored much more fully before biology can be ruled out. A sulfur-based metabolism for cloud-based life on Venus has recently been proposed (Schulze-Makuch et al., 2004). While speculative, these arguments, along with the discovery of terrestrial extremophile organisms that point toward the plausibility of survival in the Venusian clouds, establish the credibility of astrobiological exploration of Venus. Arguments for the possible existence of life on Mars or Europa are, by convention and repetition, seen as more mainstream than arguments for life elsewhere, but their logical status is similar to plausibility arguments for life on Venus. With the launch of COROT in 2006 and Kepler in 2008 the demographics of Earth-sized planets in our galaxy should finally become known. Future plans for a Terrestrial Planet Finder or Darwin-type space-based spectrograph should provide the capability of studying the atmospheric composition and other properties of terrestrial planets. One of the prime rationales for building such instruments is the possibility of identifying habitable planets or providing more generalized observational constraints on the habitable zones of stellar systems. Given the prevalence of CO2 dominated atmospheres in our own solar system, it is quite likely that a large fraction of these will be Venus-like in composition and evolutionary history. We will be observing these planets at random times in their evolution. In analogy with our own solar system, it is just as likely that we will find representatives of

  6. Intact capture of hypervelocity particles

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    1986-01-01

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  7. Intact capture of hypervelocity particles

    NASA Astrophysics Data System (ADS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  8. Rheology behavior and optimal damping effect of granular particles in a non-obstructive particle damper

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Chen, Tianning; Wang, Xiaopeng; Fang, Jianglong

    2016-03-01

    To explore the optimal damping mechanism of non-obstructive particle dampers (NOPDs), research on the relationship between the damping performance of NOPDs and the motion mode of damping particles in NOPDs was carried out based on the rheological properties of vibrated granular particles. Firstly, the damping performance of NOPDs under different excitation intensity and gap clearance was investigated via cantilever system experiments, and an approximate evaluation of the effective mass and effective damping of NOPDs was performed by fitting the experimental data to an equivalent single-degree-of-freedom (SDOF) system with no damping particles. Then the phase diagrams which could show the motion mode of damping particles under different excitation intensity and gap clearance were obtained via a series of vibration table tests. Moreover, the dissipation characteristic of damping particles was explored by the discrete element method (DEM). The study results indicate that when NOPDs play the optimal damping effect the granular Leidenfrost effect whereby the entire particle bed in NOPDs is levitated above the vibrating base by a layer of highly energetic particles is observed. Finally, the damping characteristics of NOPDs was explained by collisions and frictions between particle-particle and particle-wall based on the rheology behavior of damping particles and a new dissipation mechanism was first proposed for the optimal damping performance of NOPDs.

  9. NASA's spacecraft data system

    NASA Technical Reports Server (NTRS)

    Cudmore, Alan; Flanegan, Mark

    1993-01-01

    The NASA Small Explorer Data System (SEDS), a space flight data system developed to support the Small Explorer (SMEX) project, is addressed. The system was flown on the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX) SMEX mission, and with reconfiguration for different requirements will fly on the X-ray Timing Explorer (XTE) and the Tropical Rainfall Measuring Mission (TRMM). SEDS is also foreseen for the Hubble repair mission. Its name was changed to Spacecraft Data System (SDS) in view of expansions. Objectives, SDS hardware, and software are described. Each SDS box contains two computers, data storage memory, uplink (command) reception circuitry, downlink (telemetry) encoding circuitry, Instrument Telemetry Controller (ITC), and spacecraft timing circuitry. The SDS communicates with other subsystems over the MIL-STD-1773 data bus. The SDS software uses a real time Operating System (OS) and the C language. The OS layer, communications and scheduling layer, application task layer, and diagnostic software, are described. Decisions on the use of advanced technologies, such as ASIC's (Application Specific Integrated Circuits) and fiber optics, led to technical improvements, such as lower power and weight, without increasing the risk associated with the data system. The result was a successful SAMPEX development, integration and test, and mission using SEDS, and the upgrading of that system to SDS for TRMM and XTE.

  10. Microfabricated particle focusing device

    DOEpatents

    Ravula, Surendra K.; Arrington, Christian L.; Sigman, Jennifer K.; Branch, Darren W.; Brener, Igal; Clem, Paul G.; James, Conrad D.; Hill, Martyn; Boltryk, Rosemary June

    2013-04-23

    A microfabricated particle focusing device comprises an acoustic portion to preconcentrate particles over large spatial dimensions into particle streams and a dielectrophoretic portion for finer particle focusing into single-file columns. The device can be used for high throughput assays for which it is necessary to isolate and investigate small bundles of particles and single particles.

  11. MESSENGER: Exploring Mercury's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Krimigis, Stamatios M.; Acuna, Mario H.; Anderson, Brian J.; Baker, Daniel N.; Koehn, Patrick L.; Korth, Haje; Levi, Stefano; Mauk, Barry H.; Solomon, Sean C.; Zurbuchen, Thomas H.

    2005-01-01

    The MESSENGER mission to Mercury offers our first opportunity to explore this planet s miniature magnetosphere since the brief flybys of Mariner 10. Mercury s magnetosphere is unique in many respects. The magnetosphere of Mercury is among the smallest in the solar system; its magnetic field typically stands off the solar wind only - 1000 to 2000 km above the surface. For this reason there are no closed drift paths for energetic particles and, hence, no radiation belts. The characteristic time scales for wave propagation and convective transport are short and kinetic and fluid modes may be coupled. Magnetic reconnection at the dayside magnetopause may erode the subsolar magnetosphere allowing solar wind ions to impact directly the regolith. Inductive currents in Mercury s interior may act to modify the solar wind interaction by resisting changes due to solar wind pressure variations. Indeed, observations of these induction effects may be an important source of information on the state of Mercury s interior. In addition, Mercury s magnetosphere is the only one with its defining magnetic flux tubes rooted in a planetary regolith as opposed to an atmosphere with a conductive ionospheric layer. This lack of an ionosphere is probably the underlying reason for the brevity of the very intense, but short-lived, - 1-2 min, substorm-like energetic particle events observed by Mariner 10 during its first traversal of Mercury s magnetic tail. Because of Mercury s proximity to the sun, 0.3 - 0.5 AU, this magnetosphere experiences the most extreme driving forces in the solar system. All of these factors are expected to produce complicated interactions involving the exchange and re-cycling of neutrals and ions between the solar wind, magnetosphere, and regolith. The electrodynamics of Mercury s magnetosphere are expected to be equally complex, with strong forcing by the solar wind, magnetic reconnection at the magnetopause and in the tail, and the pick-up of planetary ions all

  12. Explore with Us

    NASA Technical Reports Server (NTRS)

    Morales, Lester

    2012-01-01

    The fundamental goal of this vision is to advance U.S. scientific, security and economic interest through a robust space exploration program. Implement a sustained and affordable human and robotic program to explore the solar system and beyond. Extend human presence across the solar system, starting with a human return to the Moon by the year 2020, in preparation for human exploration of Mars and other destinations. Develop the innovative technologies, knowledge, and infrastructures both to explore and to support decisions about the destinations for human exploration. Promote international and commercial participation in exploration to further U.S. scientific, security, and economic interests.

  13. Exploration and Mining Roadmap

    SciTech Connect

    none,

    2002-09-01

    This Exploration and Mining Technology Roadmap represents the third roadmap for the Mining Industry of the Future. It is based upon the results of the Exploration and Mining Roadmap Workshop held May 10 ñ 11, 2001.

  14. A Trigonometric Exploration.

    ERIC Educational Resources Information Center

    DiDomenico, Angelo S.

    1992-01-01

    Gives an example of an open exploration using trigonometric relationships in which the law of cosines can be deduced from the law of sines. Discusses the characteristics and value of the exploration process. (MDH)

  15. Geometrical scaling for identified particles

    NASA Astrophysics Data System (ADS)

    Praszalowicz, Michal

    2013-12-01

    We show that recently measured transverse momentum spectra of identified particles exhibit geometrical scaling (GS) in scaling variable τ=(( where m=√{m2+pT2}-m. We explore consequences of GS and show that both mid rapidity multiplicity and mean transverse momenta grow as powers of scattering energy. Furthermore, assuming Tsallis-like parametrization of the spectra we calculate the coefficients of this growth. We also show that Tsallis temperature is related to the average saturation scale.

  16. Particle Theory & Cosmology

    SciTech Connect

    Shafi, Qaisar; Barr, Steven; Gaisser, Thomas; Stanev, Todor

    2015-03-31

    investigations in cosmology, specifically on supergravity and GUT infl models, primordial gravity waves, dark matter models. The origin of baryon and dark matter in the universe has been explored by Professors Barr and Shafi The research program of Professors Gaisser and Stanev address current research topics in Particle Astrophysics, in particular atmospheric and cosmogenic neutrinos and ultra-high energy cosmic rays. Work also included use of LHC data to improve tools for interpreting cascades generated in the atmosphere by high-energy particles from the cosmos. Cosmogenic neutrinos produced by interactions of ultra-high energy cosmic rays as they propagate through the cosmic microwave background radiation provides insight into the origin of the highest energy particles in nature. Overall, the research covered topics in the energy, cosmic and intensity frontiers.

  17. Exploration cost-cutting

    SciTech Connect

    Huttrer, J.

    1996-12-31

    This presentation by Jerry Huttrer, President, Geothermal Management Company, discusses the general state of exploration in the geothermal industry today, and mentions some ways to economize and perhaps save costs of geothermal exploration in the future. He suggests an increased use of satellite imagery in the mapping of geothermal resources and the identification of hot spots. Also, coordinating with oil and gas exploration efforts, the efficiency of the exploration task could be optimized.

  18. Birth Control Explorer

    MedlinePlus

    ... Relationships STIs Media Facebook Twitter Tumblr Shares · 5 Birth Control Explorer Sort by all methods most effective methods ... MORE You are here Home » Birth Control Explorer Birth Control Explorer If you’re having sex —or if ...

  19. Explorations in Statistics: Regression

    ERIC Educational Resources Information Center

    Curran-Everett, Douglas

    2011-01-01

    Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This seventh installment of "Explorations in Statistics" explores regression, a technique that estimates the nature of the relationship between two things for which we may only surmise a mechanistic or predictive connection.…

  20. Lunar Exploration Architectures

    NASA Astrophysics Data System (ADS)

    Perino, Maria Antonietta

    The international space exploration plans foresee in the next decades multiple robotic and human missions to Moon and robotic missions to Mars, Phobos and other destinations. Notably the US has since the announcement of the US space exploration vision by President G. W. Bush in 2004 made significant progress in the further definition of its exploration programme focusing in the next decades in particular on human missions to Moon. Given the highly demanding nature of these missions, different initiatives have been recently taken at international level to discuss how the lunar exploration missions currently planned at national level could fit in a coordinate roadmap and contribute to lunar exploration. Thales Alenia Space - Italia is leading 3 studies for the European Space Agency focus on the analysis of the transportation, in-space and surface architectures required to meet ESA provided stakeholders exploration objectives and requirements. Main result of this activity is the identification of European near-term priorities for exploration missions and European long-term priorities for capability and technology developments related to planetary exploration missions. This paper will present the main studies' results drawing a European roadmap for exploration missions and capability and technology developments related to lunar exploration infrastructure development, taking into account the strategic and programmatic indications for exploration coming from ESA as well as the international exploration context.

  1. High frequency gyrokinetic particle simulation

    SciTech Connect

    Kolesnikov, R. A.; Lee, W. W.; Qin, H.; Startsev, E.

    2007-07-15

    The gyrokinetic approach for arbitrary frequency dynamics in magnetized plasmas is explored, using the gyrocenter-gauge kinetic theory. Contrary to low-frequency gyrokinetics, which views each particle as a rigid charged ring, arbitrary frequency response of a particle is described by a quickly changing Kruskal ring. This approach allows the separation of gyrocenter and gyrophase responses and thus allows for, in many situations, larger time steps for the gyrocenter push than for the gyrophase push. The gyrophase response which determines the shape of Kruskal rings can be described by a Fourier series in gyrophase for some problems, thus allowing control over the cyclotron harmonics at which the plasma responds. A computational algorithm for particle-in-cell simulation based on this concept has been developed. An example of the ion Bernstein wave is used to illustrate its numerical properties, and comparison with a direct Lorentz-force approach is presented.

  2. Asteroid exploration and utilization: The Hawking explorer

    NASA Technical Reports Server (NTRS)

    Carlson, Alan; Date, Medha; Duarte, Manny; Erian, Neil; Gafka, George; Kappler, Peter; Patano, Scott; Perez, Martin; Ponce, Edgar; Radovich, Brian

    1991-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources which may exist on asteroids could have enormous potential for aiding and enhancing human space exploration as well as life on Earth. With the possibly limitless opportunities that exist, it is clear that asteroids are the next step for human existence in space. This report comprises the efforts of NEW WORLDS, Inc. to develop a comprehensive design for an asteroid exploration/sample return mission. This mission is a precursor to proof-of-concept missions that will investigate the validity of mining and materials processing on an asteroid. Project STONER (Systematic Transfer of Near Earth Resources) is based on two utilization scenarios: (1) moving an asteroid to an advantageous location for use by Earth; and (2) mining an asteroids and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plane for humans to utilize asteroid resources. The report concentrates specifically on the selection of the most promising asteroids for exploration and the development of an exploration scenario. Future utilization as well as subsystem requirements of an asteroid sample return probe are also addressed.

  3. Capability 9.1 Exploration

    NASA Technical Reports Server (NTRS)

    Eckelkamp, Rick; Blacic, Jim

    2005-01-01

    The exploration challenge are: To build an efficient, cost effective exploration infrastructure, To coordinate exploration robots & crews from multiple. earth sites to accomplish science and exploration objectives. and To maximize self-sufficiency of the lunar/planetary exploration team.

  4. Effect of particle hardness on the penetration behavior of fabrics intercalated with dry particles and concentrated particle-fluid suspensions.

    PubMed

    Kalman, Dennis P; Merrill, Richard L; Wagner, Norman J; Wetzel, Eric D

    2009-11-01

    The penetration behavior of Kevlar fabric intercalated with dry particles and shear thickening fluids (STF), highly concentrated fluid-particle suspensions, is presented. In particular, the role of particle hardness is explored by comparing fabric treatments containing SiO(2) particles, which are significantly harder than Kevlar, to treatments containing softer poly(methyl methacrylate) (PMMA) particles. The fabric testing includes yarn pull-out, quasi-static spike puncture, and ballistic penetration resistance, performed on single fabric layers. It was found that both dry particle and STF treatments resulted in improvements in fabric properties relative to neat or poly(ethylene glycol) (PEG) treated fabrics. On comparison of treatments with different particle hardness, the SiO(2) materials performed better in all tests than comparable PMMA materials, although the SiO(2) treatments caused yarn failure in pull-out testing, reducing the total pull-out energy. In addition, resistance to yarn pull-out was found to be substantially higher for STF-treated fabrics than for dry particle treated fabrics. However, both dry particle addition and STF treatments exhibited comparable enhancements in puncture and ballistic resistance. These observations suggest that viscous stress transfer, friction, and physical entrainment of hard particles into filaments contribute to the demonstrated improvements in the properties of protective fabrics treated with shear thickening fluids. PMID:20356133

  5. Exploration Blueprint: Data Book

    NASA Astrophysics Data System (ADS)

    Drake, Bret G.

    2007-02-01

    The material contained in this report was compiled to capture the work performed by the National Aeronautics and Space Administration's (NASA's) Exploration study team in the late 2002 timeframe. The "Exploration Blueprint Data Book" documents the analyses and findings of the 90-day Agency-wide study conducted from September - November 2002. During the summer of 2002, the NASA Deputy Administrator requested that a study be performed with the following objectives: (1) Develop the rationale for exploration beyond low-Earth orbit (2) Develop roadmaps for how to accomplish the first steps through humans to Mars (3) Develop design reference missions as a basis for the roadmaps 4) Make recommendations on what can be done now to effect this future This planning team, termed the Exploration Blueprint, performed architecture analyses to develop roadmaps for how to accomplish the first steps beyond LEO through the human exploration of Mars. The previous NASA Exploration Team activities laid the foundation and framework for development of NASA's Integrated Space Plan. The reference missions resulting from the analysis performed by the Exploration Blueprint team formed the basis for requirement definition, systems development, technology roadmapping, and risk assessments for future human exploration beyond low-Earth orbit. Emphasis was placed on developing recommendations on what could be done now to effect future exploration activities. The Exploration Blueprint team embraced the "Stepping Stone" approach to exploration where human and robotic activities are conducted through progressive expansion outward beyond low-Earth orbit. Results from this study produced a long-term strategy for exploration with near-term implementation plans, program recommendations, and technology investments. Specific results included the development of a common exploration crew vehicle concept, a unified space nuclear strategy, focused bioastronautics research objectives, and an integrated human

  6. Exploration Blueprint: Data Book

    NASA Technical Reports Server (NTRS)

    Drake, Bret G. (Editor)

    2007-01-01

    The material contained in this report was compiled to capture the work performed by the National Aeronautics and Space Administration's (NASA's) Exploration study team in the late 2002 timeframe. The "Exploration Blueprint Data Book" documents the analyses and findings of the 90-day Agency-wide study conducted from September - November 2002. During the summer of 2002, the NASA Deputy Administrator requested that a study be performed with the following objectives: (1) Develop the rationale for exploration beyond low-Earth orbit (2) Develop roadmaps for how to accomplish the first steps through humans to Mars (3) Develop design reference missions as a basis for the roadmaps 4) Make recommendations on what can be done now to effect this future This planning team, termed the Exploration Blueprint, performed architecture analyses to develop roadmaps for how to accomplish the first steps beyond LEO through the human exploration of Mars. The previous NASA Exploration Team activities laid the foundation and framework for development of NASA's Integrated Space Plan. The reference missions resulting from the analysis performed by the Exploration Blueprint team formed the basis for requirement definition, systems development, technology roadmapping, and risk assessments for future human exploration beyond low-Earth orbit. Emphasis was placed on developing recommendations on what could be done now to effect future exploration activities. The Exploration Blueprint team embraced the "Stepping Stone" approach to exploration where human and robotic activities are conducted through progressive expansion outward beyond low-Earth orbit. Results from this study produced a long-term strategy for exploration with near-term implementation plans, program recommendations, and technology investments. Specific results included the development of a common exploration crew vehicle concept, a unified space nuclear strategy, focused bioastronautics research objectives, and an integrated human

  7. Emergent flux from particle collisions near a Kerr black hole

    SciTech Connect

    Banados, Maximo; Hassanain, Babiker; Silk, Joseph; West, Stephen M.

    2011-01-15

    The escape fraction at infinity is evaluated for massless particles produced in collisions of weakly interacting particles accreted into a density spike near the particle horizon of an extremal Kerr black hole, for the case of equatorial orbits. We compare with the Schwarzschild case, and argue that in the case of extremal black holes, redshifted signatures can be produced that could potentially explore the physics of particle collisions at center of mass energies that extend beyond those of any feasible terrestrial accelerator.

  8. A novel clustering approach to positron emission particle tracking

    NASA Astrophysics Data System (ADS)

    Wiggins, Cody; Santos, Roque; Ruggles, Arthur

    2016-03-01

    A novel approach to positron emission particle tracking is presented based on determining regions of space with high density of line of response crossing via clustering. The method is shown to be able to accurately track multiple particles in systems where the number of particles is unknown and in which particles can enter and leave the field of view of the scanning system. This method is explored in various environments and its parametric dependence is studied.

  9. Distribution of lead in single atmospheric particles

    NASA Astrophysics Data System (ADS)

    Murphy, D. M.; Hudson, P. K.; Cziczo, D. J.; Gallavardin, S.; Froyd, K. D.; Johnston, M. V.; Middlebrook, A. M.; Reinard, M. S.; Thomson, D. S.; Thornberry, T.; Wexler, A. S.

    2007-03-01

    Three independent single particle mass spectrometers measured Pb in individual aerosol particles. These data provide unprecedented sensitivity and statistical significance for the measurement of Pb in single particles. This paper explores the reasons for the frequency of Pb in fine particles now that most gasoline is unleaded. Trace amounts of Pb were found in 5 to 25% of 250 to 3000 nm diameter particles sampled by both aircraft and surface instruments in the eastern and western United States. Over 5% of particles at a mountain site in Switzerland contained Pb. Particles smaller than 100 nm with high Pb content were also observed by an instrument that was only operated in urban areas. Lead was found on all types of particles, including Pb present on biomass burning particles from remote fires. Less common particles with high Pb contents contributed a majority of the total amount of Pb. Single particles with high Pb content often also contained alkali metals, Zn, Cu, Sn, As, and Sb. The association of Pb with Zn and other metals is also found in IMPROVE network filter data from surface sites. Sources of airborne Pb in the United States are reviewed for consistency with these data. The frequent appearance of trace Pb is consistent with widespread emissions of fine Pb particles from combustion sources followed by coagulation with larger particles during long-range transport. Industrial sources that directly emit Pb-rich particles also contribute to the observations. Clean regions of the western United States show some transport of Pb from Asia but most Pb over the United States comes from North American sources. Resuspension of Pb from soil contaminated by the years of leaded gasoline was not directly apparent.

  10. Distribution of lead in single atmospheric particles

    NASA Astrophysics Data System (ADS)

    Murphy, D. M.; Hudson, P. K.; Cziczo, D. J.; Gallavardin, S.; Froyd, K. D.; Johnston, M. V.; Middlebrook, A. M.; Reinard, M. S.; Thomson, D. S.; Thornberry, T.; Wexler, A. S.

    2007-06-01

    Three independent single particle mass spectrometers measured Pb in individual aerosol particles. These data provide unprecedented sensitivity and statistical significance for the measurement of Pb in single particles. This paper explores the reasons for the frequency of Pb in fine particles now that most gasoline is unleaded. Trace amounts of Pb were found in 5 to 25% of 250 to 3000 nm diameter particles sampled by both aircraft and surface instruments in the eastern and western United States. Over 5% of particles at a mountain site in Switzerland contained Pb. Particles smaller than 100 nm with high Pb content were also observed by an instrument that was only operated in urban areas. Lead was found on all types of particles, including Pb present on biomass burning particles from remote fires. Less common particles with high Pb contents contributed a majority of the total amount of Pb. Single particles with high Pb content often also contained alkali metals, Zn, Cu, Sn, As, and Sb. The association of Pb with Zn and other metals is also found in IMPROVE network filter data from surface sites. Sources of airborne Pb in the United States are reviewed for consistency with these data. The frequent appearance of trace Pb is consistent with widespread emissions of fine Pb particles from combustion sources followed by coagulation with larger particles during long-range transport. Industrial sources that directly emit Pb-rich particles also contribute to the observations. Clean regions of the western United States show some transport of Pb from Asia but most Pb over the United States comes from North American sources. Resuspension of Pb from soil contaminated by the years of leaded gasoline was not directly apparent.

  11. Explosive formation of coherent particle jets

    NASA Astrophysics Data System (ADS)

    Frost, D. L.; Ruel, J.-F.; Zarei, Z.; Goroshin, S.; Gregoire, Y.; Zhang, F.; Milne, A.; Longbottom, A.

    2014-05-01

    A coherent jet of particles may be generated by accelerating a conical volume of particles by detonating a layer of explosive lining the outside of the cone. Experiments have been carried out to determine the dependence of the velocity history and coherency of the jet on the particle properties and the ratio of the masses of the particles and explosive. Steel particles form thin, coherent jets, whereas lighter glass particles lead to more diffuse jets. For steel particles, the cone angle had little effect on the coherency of the jet. The efficiency of the conversion of chemical to kinetic energy is explored by comparing the experimental jet velocity with the velocity predicted from a formulation of the Gurney method for a conical geometry. The effect of particle density and cone angle on the jet formation and development was also investigated using a multimaterial hydrocode. The simulations give insight into the extent of the deformation of the particle bed in the early stages of explosive particle dispersal.

  12. Electrostatic particle collection in vacuum

    NASA Astrophysics Data System (ADS)

    Afshar-Mohajer, Nima; Damit, Brian; Wu, Chang-Yu; Sorloaica-Hickman, Nicoleta

    2011-09-01

    Lunar grains accumulate charges due to solar-based ionizing radiations, and the repelling action of like-charged particles causes the levitation of lunar dust. The lunar dust deposit on sensitive and costly surfaces of investigative equipment is a serious concern in lunar explorations. Inspired by electrostatic precipitators (ESPs), the Electrostatic Lunar Dust Collector (ELDC) was proposed for collecting already charged lunar dust particles to prevent the lunar dust threat. As the conditions for terrestrial counterparts are not valid in the lunar environment, equations developed for terrestrial devices yield incorrect predictions in lunar application. Hence, a mathematical model was developed for the ELDC operating in vacuum to determine its collection efficiency. The ratios of electrical energy over potential energy, kinetic energy over potential energy and the ratio of ELDC dimensions were identified to be the key dimensionless parameters. Sensitivity analyses of the relevant parameters showed that depending on ELDC orientation, smaller particles would be collected more easily at vertical orientation, whereas larger particles were easier to collect in a horizontal ELDC configuration. In the worst case scenario, the electrostatic field needed to be 10 times stronger in the vertical mode in order to adequately collect larger particles. The collection efficiency was very sensitive to surface potential of lunar dust and it reached the maximum when surface potential was between 30 and 120 V. Except for regions of the lunar day side with surface potential close to zero, providing 1 kV ( E = 20 kV m -1) with the ELDC was more than enough for collecting all the particles in the most critical orientation. The needed field strength was about 4000 times less than that for repelling 1-μm size particles already settled on the surfaces. The analysis shows that the ELDC offers a viable solution for lunar dust control due to its effectiveness, ease of cleaning and low voltage

  13. NASA's Exploration Architecture

    NASA Technical Reports Server (NTRS)

    Tyburski, Timothy

    2006-01-01

    A Bold Vision for Space Exploration includes: 1) Complete the International Space Station; 2) Safely fly the Space Shuttle until 2010; 3) Develop and fly the Crew Exploration Vehicle no later than 2012; 4) Return to the moon no later than 2020; 5) Extend human presence across the solar system and beyond; 6) Implement a sustained and affordable human and robotic program; 7) Develop supporting innovative technologies, knowledge, and infrastructures; and 8) Promote international and commercial participation in exploration.

  14. Technology Drives Exploration

    NASA Video Gallery

    NASA is investing in the future by advancing its capabilities and developing transformative technologies required to reach the challenging destinations that await exploration. The Space Technology ...

  15. The Cosmic Background Explorer.

    ERIC Educational Resources Information Center

    Gulkis, Samuel; And Others

    1990-01-01

    Outlines the Cosmic Background Explorer (COBE) mission to measure celestial radiation. Describes the instruments used and experiments involving differential microwave radiometers, and a far infrared absolute spectrophotometer. (YP)

  16. NASA Exploration Design Challenge

    NASA Video Gallery

    From the International Space Station, astronaut Sunita Williams welcomes participants to the NASA Exploration Design Challenge and explains the uncertainties about the effects of space radiation on...

  17. Explorer Program: X-ray Timing Explorer

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This booklet describes the X-ray Timing Explorer (XTE), one in a series of Explorer missions administered by the National Aeronautics and Space Administration's (NASA) Office of Space Science and managed by the NASA Goddard Space Flight Center (GSFC). The X-ray astronomy observatory is scheduled for launch into low-Earth orbit by Delta 2 expendable launch vehicle in late summer of 1995. The mission is expected to operate for at least 2 years and will carry out in-depth timing and spectral studies of the X-ray sources in the 2 to 200 kilo-electron Volt (keV) range. XTE is intended to study the temporal and broad-band spectral phenomena associated with stellar and galactic systems containing compact objects, including neutron stars, white dwarfs, and black holes.

  18. The exploration metaphor

    NASA Technical Reports Server (NTRS)

    Mcgreevy, Michael W.

    1991-01-01

    NASA's experience in planetary exploration has demonstrated that the desktop workstation is inadequate for many visualization situations. The primary mission displays for the unmanned Surveyor missions to the moon during the mid-1960's, for example, were environmental images assembled on the inside surfaces of spherical shells. Future exploration missions will greatly benefit from advances in digital computer and display technology, but there remain unmet user interface needs. Alternative user interfaces and metaphors are needed for planetary exploration and other interactions with complex spatial environments. These interfaces and metaphors would enable the user to directly explore environments and naturally manipulate objects in those environments. Personal simulators, virtual workstations, and telepresence user interfaces are systems capable of providing this integration of user space and task space. The Exploration Metaphor is a useful concept for guiding the design of user interfaces for virtual environments and telepresence. To apply the Exploration Metaphor is to assert that computing is like exploration, and to support objects, operations, and contexts comparable to those encountered in the exploration of natural environments. The Exploration Metaphor, under development for user interfaces in support of NASA's planetary exploration missions and goals, will also benefit other applications where complex spatial information must be visualized. Visualization methods and systems for planetary exploration are becoming increasingly integrated and interactive as computing technology improves. These advances will benefit from virtual environment and telepresence interface technology. A key development has been the processing of multiple images and other sensor data to create detailed digital models of the planets and moons. Data from images of the Earth, Mars, and Miranda, for example, have been converted into 3D models, and dynamic virtual fly-overs have been

  19. Magnetometer-only attitude and rate determination for a gyro-less spacecraft

    NASA Technical Reports Server (NTRS)

    Natanson, G. A.; Challa, M. S.; Deutschmann, J.; Baker, D. F.

    1994-01-01

    Attitude determination algorithms that requires only the earth's magnetic field will be useful for contingency conditions. One way to determine attitude is to use the time derivative of the magnetic field as the second vector in the attitude determination process. When no gyros are available, however, attitude determination becomes difficult because the rates must be propagated via integration of Euler's equation, which in turn requires knowledge of the initial rates. The spacecraft state to be determined must then include not only the attitude but also rates. This paper describes a magnetometer-only attitude determination scheme with no a priori knowledge of the spacecraft state, which uses a deterministic algorithm to initialize an extended Kalman filter. The deterministic algorithm uses Euler's equation to relate the time derivatives of the magnetic field in the reference and body frames and solves the resultant transcendental equations for the coarse attitude and rates. An important feature of the filter is that its state vector also includes corrections to the propagated rates, thus enabling it to generate highly accurate solutions. The method was tested using in-flight data from the Solar, Anomalous, and Magnetospheric Particles Explorer (SAMPEX), a Small Explorer spacecraft. SAMPEX data using several eclipse periods were used to simulate conditions that may exist during the failure of the on-board digital sun sensor. The combined algorithm has been found effective, yielding accuracies of 1.5 deg in attitude (within even nominal mission requirements) and 0.01 degree per second (deg/sec) in the rates.

  20. Explorations in Statistics: Power

    ERIC Educational Resources Information Center

    Curran-Everett, Douglas

    2010-01-01

    Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This fifth installment of "Explorations in Statistics" revisits power, a concept fundamental to the test of a null hypothesis. Power is the probability that we reject the null hypothesis when it is false. Four things affect…

  1. We Are the Explorers

    NASA Video Gallery

    Why do we explore? Simply put, it is part of who we are, and it is something we have done throughout our history. In NASA’s new video, “We Are the Explorers,” we take a look at that tradition...

  2. Mars exploration planning

    NASA Technical Reports Server (NTRS)

    Eppler, Dean B.; Buoni, Corinne; Niehoff, John

    1993-01-01

    Mars exploration planning is discussed which is based on three scientific objectives: to understand Mars' geologic and geophysical evolution; to understand the present state and past evolution of Martian climate, and to determine the state of present biological activity and past life. The plan assumes a 25-year planning horizon, from 1995-2020, and includes both broad-scale and local exploration capabilities.

  3. Why Man Explores

    NASA Technical Reports Server (NTRS)

    1976-01-01

    This NASA Educational Publication was prepared from a transcript of a panel discussion held on July 2, 1976, in conjunction with the Viking Missions to Mars. The members of the Why Man Explores panel were selected as authorities in classical disciplines relating to exploration.

  4. Planetary Exploration in ESA

    NASA Technical Reports Server (NTRS)

    Schwehm, Gerhard H.

    2005-01-01

    A viewgraph presentation on planetary exploration in the European Space Agency is shown. The topics include: 1) History of the Solar System Material; 2) ROSETTA: The Comet Mission; 3) A New Name For The Lander: PHILAE; 4) The Rosetta Mission; 5) Lander: Design Characteristics; 6) SMART-1 Mission; 7) MARS Express VENUS Express; 8) Planetary Exploration in ESA The Future.

  5. Dynamics explorer data analysis

    NASA Technical Reports Server (NTRS)

    Reiff, Patricia H.

    1993-01-01

    Work in the following areas is discussed: plasma physics of the auroral acceleration region; electrodynamic coupling as a function of substorm phase and interplanetary magnetic field (IMF) direction; and particle injection in the magnetospheric cusp.

  6. Exploration Laboratory Analysis - ARC

    NASA Technical Reports Server (NTRS)

    Krihak, Michael K.; Fung, Paul P.

    2012-01-01

    The Exploration Laboratory Analysis (ELA) project supports the Exploration Medical Capability (ExMC) risk, Risk of Inability to Adequately Treat an Ill or Injured Crew Member, and ExMC Gap 4.05: Lack of minimally invasive in-flight laboratory capabilities with limited consumables required for diagnosing identified Exploration Medical Conditions. To mitigate this risk, the availability of inflight laboratory analysis instrumentation has been identified as an essential capability in future exploration missions. Mission architecture poses constraints on equipment and procedures that will be available to treat evidence-based medical conditions according to the Space Medicine Exploration Medical Conditions List (SMEMCL). The SMEMCL provided diagnosis and treatment for the evidence-based medical conditions and hence, a basis for developing ELA functional requirements.

  7. Investigation of Drag and Heat Transfer for Martian Dust Particles

    NASA Astrophysics Data System (ADS)

    Ozawa, T.; Suzuki, T.; Takayanagi, H.; Fujita, K.

    2011-05-01

    A Mars non-stop dust sample return project has been going on in a Mars exploration mission at Japan Aerospace Exploration Agency. In the project, sampling of Martian dust particles is planned between 35 and 45 km, and thus, the survivability of micron-size particles during traveling through a hot-temperature shock is crucial. In this work, the dust particle heating was investigated from macroscopic and microscopic viewpoints. Drag and heat transfer coefficients calculated by the direct simulation Monte Carlo method were found to agree well with Koshmarov and Svirshevskii and free-molecule models at both altitudes, and particle heating estimations calculated by these models were validated.

  8. Diffraction of entangled particles by light gratings

    NASA Astrophysics Data System (ADS)

    Sancho, Pedro

    2015-04-01

    We analyze the diffraction regime of the Kapitza-Dirac effect for particles entangled in momentum. The detection patterns show two-particle interferences. In the single-mode case we identify a discontinuity in the set of joint detection probabilities, associated with the disconnected character of the space of non-separable states. For Gaussian multi-mode states we derive the diffraction patterns, providing an example of the dependence of the light-matter interaction on entanglement. When the particles are identical, we can explore the relation between exchange and entanglement effects. We find a complementary behavior between overlapping and Schmidt's number. In particular, symmetric entanglement can cancel the exchange effects.

  9. Particles with changeable topology in nematic colloids.

    PubMed

    Ravnik, Miha; Čopar, Simon; Žumer, Slobodan

    2015-09-01

    We show that nematic colloids can serve as a highly variable and controllable platform for studying inclusions with changeable topology and their effects on the surrounding ordering fields. We explore morphing of toroidal and knotted colloidal particles into effective spheres, distinctively changing their Euler characteristic and affecting the surrounding nematic field, including topological defect structures. With toroidal particles, the inner nematic defect eventually transitions from a wide loop to a point defect (a small loop). Trefoil particles become linked with two knotted defect loops, mutually forming a three component link, that upon tightening transform into a two-component particle-defect loop link. For more detailed topological analysis, Pontryagin-Thom surfaces are calculated and visualised, indicating an interesting cascade of defect rewirings caused by the shape morphing of the knotted particles. PMID:26291540

  10. Particles with changeable topology in nematic colloids

    NASA Astrophysics Data System (ADS)

    Ravnik, Miha; Čopar, Simon; Žumer, Slobodan

    2015-09-01

    We show that nematic colloids can serve as a highly variable and controllable platform for studying inclusions with changeable topology and their effects on the surrounding ordering fields. We explore morphing of toroidal and knotted colloidal particles into effective spheres, distinctively changing their Euler characteristic and affecting the surrounding nematic field, including topological defect structures. With toroidal particles, the inner nematic defect eventually transitions from a wide loop to a point defect (a small loop). Trefoil particles become linked with two knotted defect loops, mutually forming a three component link, that upon tightening transform into a two-component particle-defect loop link. For more detailed topological analysis, Pontryagin-Thom surfaces are calculated and visualised, indicating an interesting cascade of defect rewirings caused by the shape morphing of the knotted particles.

  11. Lagrangian coherent structures and inertial particle dynamics

    NASA Astrophysics Data System (ADS)

    Sudharsan, M.; Brunton, Steven L.; Riley, James J.

    2016-03-01

    In this work we investigate the dynamics of inertial particles using finite-time Lyapunov exponents (FTLE). In particular, we characterize the attractor and repeller structures underlying preferential concentration of inertial particles in terms of FTLE fields of the underlying carrier fluid. Inertial particles that are heavier than the ambient fluid (aerosols) attract onto ridges of the negative-time fluid FTLE. This negative-time FTLE ridge becomes a repeller for particles that are lighter than the carrier fluid (bubbles). We also examine the inertial FTLE (iFTLE) determined by the trajectories of inertial particles evolved using the Maxey-Riley equations with nonzero Stokes number and density ratio. Finally, we explore the low-pass filtering effect of Stokes number. These ideas are demonstrated on two-dimensional numerical simulations of the unsteady double-gyre flow.

  12. Particle Tracks in Aerogel

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In an experiment using a special air gun, particles are shot into aerogel at high velocities. Closeup of particles that have been captured in aerogel are shown here. The particles leave a carrot-shaped trail in the aerogel. Aerogel was used on the Stardust spacecraft to capture comet particles from Comet Wild 2.

  13. Experimental drag histories of shocked spherical particles

    NASA Astrophysics Data System (ADS)

    Prestridge, Katherine; Orlicz, Greg; Martinez, Adam

    2015-11-01

    The horizontal shock tube (HST) facility at Los Alamos is used to investigate the drag forces on micrometer-sized particles dispersed in air when they are accelerated by a shock. Eight-frame, high-speed particle tracking velocimetry/accelerometry (PTVA) diagnostics are implemented to measure the trajectory of individual particles with high spatial and temporal resolution, and a shadowgraphy system is used to measure the shock position on each image. We present experiments over a range of Reynolds numbers, Mach numbers, particle sizes, and particle densities that explore the drag forces on solid, spherical, non-deforming particles. Experimental drag coefficients are calculated from eight dynamic measurements of particle position versus time, for Mach 1.3 and Mach 1.2 experiments. Experimental results show drag coefficients significantly larger than those predicted by the standard drag model for solid, spherical particles. These results are consistent with measurements made by Rudinger (1970) and Sommerfeld (1985). We will present experimental results and analysis of unsteady drag as a function of particle Reynolds number, Mach number and Stokes number.

  14. Health effects of residential wood smoke particles: the importance of combustion conditions and physicochemical particle properties

    PubMed Central

    Kocbach Bølling, Anette; Pagels, Joakim; Yttri, Karl Espen; Barregard, Lars; Sallsten, Gerd; Schwarze, Per E; Boman, Christoffer

    2009-01-01

    Background Residential wood combustion is now recognized as a major particle source in many developed countries, and the number of studies investigating the negative health effects associated with wood smoke exposure is currently increasing. The combustion appliances in use today provide highly variable combustion conditions resulting in large variations in the physicochemical characteristics of the emitted particles. These differences in physicochemical properties are likely to influence the biological effects induced by the wood smoke particles. Outline The focus of this review is to discuss the present knowledge on physicochemical properties of wood smoke particles from different combustion conditions in relation to wood smoke-induced health effects. In addition, the human wood smoke exposure in developed countries is explored in order to identify the particle characteristics that are relevant for experimental studies of wood smoke-induced health effects. Finally, recent experimental studies regarding wood smoke exposure are discussed with respect to the applied combustion conditions and particle properties. Conclusion Overall, the reviewed literature regarding the physicochemical properties of wood smoke particles provides a relatively clear picture of how these properties vary with the combustion conditions, whereas particle emissions from specific classes of combustion appliances are less well characterised. The major gaps in knowledge concern; (i) characterisation of the atmospheric transformations of wood smoke particles, (ii) characterisation of the physicochemical properties of wood smoke particles in ambient and indoor environments, and (iii) identification of the physicochemical properties that influence the biological effects of wood smoke particles. PMID:19891791

  15. Exploring Black Hole Dynamics

    NASA Astrophysics Data System (ADS)

    Chung, Hyeyoun

    2015-10-01

    This thesis explores the evolution of different types of black holes, and the ways in which black hole dynamics can be used to answer questions about other physical systems. We first investigate the differences in observable gravitational effects between a four-dimensional Randall-Sundrum (RS) braneworld universe compared to a universe without the extra dimension, by considering a black hole solution to the braneworld model that is localized on the brane. When the brane has a negative cosmological constant, then for a certain range of parameters for the black hole, the intersection of the black hole with the brane approximates a Banados-Teitelboim-Zanelli (BTZ) black hole on the brane with corrections that fall off exponentially outside the horizon. We compute the quasinormal modes of the braneworld black hole, and compare them to the known quasinormal modes of the three-dimensional BTZ black hole. We find that there are two distinct regions for the braneworld black hole solutions that are reflected in the dependence of the quasinormal modes on the black hole mass. The imaginary parts of the quasinormal modes display phenomenological similarities to the quasinormal modes of the three-dimensional BTZ black hole, indicating that nonlinear gravitational effects may not be enough to distinguish between a lower-dimensional theory and a theory derived from a higher-dimensional braneworld. Secondly, we consider the evolution of non-extremal black holes in N=4, d=2 supergravity, and investigate how such black holes might evolve over time if perturbed away from extremality. We study this problem in the probe limit by finding tunneling amplitudes for a Dirac field in a single-centered background, which gives the decay rates for the emission of charged probe black holes from the central black hole. We find that there is no minimum to the potential for the probe particles at a finite distance from the central black hole, so any probes that are emitted escape to infinity. If

  16. Virtual Energetic Particle Observatory (VEPO)

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Lal, Nand; McGuire, Robert E.; Szabo, Adam; Narock, Thomas W.; Armstrong, Thomas P.; Manweiler, Jerry W.; Patterson, J. Douglas; Hill, Matthew E.; Vandergriff, Jon D.; McKibben, Robert B.; Lopate, Clifford; Tranquille, Cecil

    2008-01-01

    The Virtual Energetic Particle Observatory (VEPO) focuses on improved discovery, access, and usability of heliospheric energetic particle and ancillary data products from selected spacecraft and sub-orbital instruments of the heliophysics data environment. The energy range of interest extends over the full range of particle acceleration from keV energies of suprathermal seed particles to GeV energies of galactic cosmic ray particles. Present spatial coverage is for operational and legacy spacecraft operating from the inner to the outer heliosphere, e.g. from measurements by the two Helios spacecraft to 0.3 AU to the inner heliosheath region now being traversed by the two Voyager spacecraft. This coverage will eventually be extended inward to ten solar radii by the planned NASA solar probe mission and at the same time beyond the heliopause into the outer heliosheath by continued Voyager operations. The geospace fleet of spacecraft providing near-Earth interplanetary measurements, selected magnetospheric spacecraft providing direct measurements of penetrating interplanetary energetic particles, and interplanetary cruise measurements from planetary spacecraft missions further extend VEPO resources to the domain of geospace and planetary interactions. Ground-based (e.g., neutron monitor) and high-altitude suborbital measurements can expand coverage to the highest energies of galactic cosmic rays affected by heliospheric interaction and of solar energetic particles. Science applications include investigation of solar flare and coronal mass ejection events. acceleration and transport of interplanetary particles within the inner heliosphere, cosmic ray interactions with planetary surfaces and atmospheres, sources of suprathermal and anomalous cosmic ray ions in the outer heliosphere, and solar cycle modulation of galactic cosmic rays. Robotic and human exploration, and eventual habitation, of planetary and space environments beyond the Earth require knowledge of radiation

  17. Virtual Energetic Particle Observatory (VEPO)

    NASA Astrophysics Data System (ADS)

    Cooper, J. F.; Lal, N.; McGuire, R. E.; Szabo, A.; Narock, T. W.; Armstrong, T. P.; Manweiler, J. W.; Patterson, J. D.; Hill, M. E.; Vandergriff, J. D.; McKibben, R. B.; Lopate, C.; Tranquille, C.

    2008-12-01

    The Virtual Energetic Particle Observatory (VEPO) focuses on improved discovery, access, and usability of heliospheric energetic particle and ancillary data products from selected spacecraft and sub-orbital instruments of the heliophysics data environment. The energy range of interest extends over the full range of particle acceleration from keV energies of suprathermal seed particles to GeV energies of galactic cosmic ray particles. Present spatial coverage is for operational and legacy spacecraft operating from the inner to the outer heliosphere, e.g. from measurements by the two Helios spacecraft to 0.3 AU to the inner heliosheath region now being traversed by the two Voyager spacecraft. This coverage will eventually be extended inward to ten solar radii by the planned NASA solar probe mission and at the same time beyond the heliopause into the outer heliosheath by continued Voyager operations. The geospace fleet of spacecraft providing near-Earth interplanetary measurements, selected magnetospheric spacecraft providing direct measurements of penetrating interplanetary energetic particles, and interplanetary cruise measurements from planetary spacecraft missions further extend VEPO resources to the domain of geospace and planetary interactions. Ground-based (e.g., neutron monitor) and high-altitude suborbital measurements can expand coverage to the highest energies of galactic cosmic rays affected by heliospheric interaction and of solar energetic particles. Science applications include investigation of solar flare and coronal mass ejection events, acceleration and transport of interplanetary particles within the inner heliosphere, cosmic ray interactions with planetary surfaces and atmospheres, sources of suprathermal and anomalous cosmic ray ions in the outer heliosphere, and solar cycle modulation of galactic cosmic rays. Robotic and human exploration, and eventual habitation, of planetary and space environments beyond the Earth require knowledge of radiation

  18. Lunar Daylight Exploration

    NASA Technical Reports Server (NTRS)

    Griffin, Brand Norman

    2010-01-01

    With 1 rover, 2 astronauts and 3 days, the Apollo 17 Mission covered over 30 km, setup 10 scientific experiments and returned 110 kg of samples. This is a lot of science in a short time and the inspiration for a barebones, return-to-the-Moon strategy called Daylight Exploration. The Daylight Exploration approach poses an answer to the question, What could the Apollo crew have done with more time and today s robotics? In contrast to more ambitious and expensive strategies that create outposts then rely on pressurized rovers to drive to the science sites, Daylight Exploration is a low-overhead approach conceived to land near the scientific site, conduct Apollo-like exploration then leave before the sun goes down. A key motivation behind Daylight Exploration is cost reduction, but it does not come at the expense of scientific exploration. As a goal, Daylight Exploration provides access to the top 10 science sites by using the best capabilities of human and robotic exploration. Most science sites are within an equatorial band of 26 degrees latitude and on the Moon, at the equator, the day is 14 Earth days long; even more important, the lunar night is 14 days long. Human missions are constrained to 12 days because the energy storage systems required to operate during the lunar night adds mass, complexity and cost. In addition, short missions are beneficial because they require fewer consumables, do not require an airlock, reduce radiation exposure, minimize the dwell-time for the ascent and orbiting propulsion systems and allow a low-mass, campout accommodations. Key to Daylight Exploration is the use of piloted rovers used as tele-operated science platforms. Rovers are launched before or with the crew, and continue to operate between crew visits analyzing and collecting samples during the lunar daylight

  19. On the Interaction Between Highly Energetic Charged Particles and the Lunar Regolith

    NASA Astrophysics Data System (ADS)

    Jordan, A. P.; Stubbs, T. J.; Zeitlin, C.; Spence, H. E.; Schwadron, N. A.; Zimmerman, M. I.; Farrell, W. M.

    2012-03-01

    In this study we explore how galactic cosmic rays and solar energetic particles contribute to deep dielectric charging within the lunar regolith and how these particles affect lunar surface charging in tenuous plasma environments.

  20. Human Exploration of Mars

    NASA Astrophysics Data System (ADS)

    Gwynne, Owen; McKay, Chris; Zubrin, Robert

    1991-06-01

    Novel approaches to the human exploration of Mars are considered with emphasis on a space suit design, extraterrestrial surface mobility, and water supply. A possible way of transporting personnel on the surface of Mars uses a suborbital rocket that will hop from one site to the next, refuelling each time it lands and giving the Martian explorers effective global mobility. Telepresence could be used to avoid limiting the people on Mars to a small exploration area as a result of a lack of transportation infrastructure. Drawings and photographs are included.

  1. Explorer I Architects

    NASA Technical Reports Server (NTRS)

    1958-01-01

    The three men responsible for the success of Explorer 1, America's first Earth satellite which was launched January 31, 1958. At left is Dr. William H. Pickering, former director of JPL, which built and operated the satellite. Dr. James A. van Allen, center, of the State University of Iowa, designed and built the instrument on Explorer that discovered the radiation belts which circle the Earth. At right is Dr. Wernher von Braun, leader of the Army's Redstone Arsenal team which built the first stage Redstone rocket that launched Explorer 1.

  2. Tomographic PIV: particles versus blobs

    NASA Astrophysics Data System (ADS)

    Champagnat, Frédéric; Cornic, Philippe; Cheminet, Adam; Leclaire, Benjamin; Le Besnerais, Guy; Plyer, Aurélien

    2014-08-01

    We present an alternative approach to tomographic particle image velocimetry (tomo-PIV) that seeks to recover nearly single voxel particles rather than blobs of extended size. The baseline of our approach is a particle-based representation of image data. An appropriate discretization of this representation yields an original linear forward model with a weight matrix built with specific samples of the system’s point spread function (PSF). Such an approach requires only a few voxels to explain the image appearance, therefore it favors much more sparsely reconstructed volumes than classic tomo-PIV. The proposed forward model is general and flexible and can be embedded in a classical multiplicative algebraic reconstruction technique (MART) or a simultaneous multiplicative algebraic reconstruction technique (SMART) inversion procedure. We show, using synthetic PIV images and by way of a large exploration of the generating conditions and a variety of performance metrics, that the model leads to better results than the classical tomo-PIV approach, in particular in the case of seeding densities greater than 0.06 particles per pixel and of PSFs characterized by a standard deviation larger than 0.8 pixels.

  3. Exploring the Nature of Contact Freezing

    NASA Astrophysics Data System (ADS)

    Kiselev, A. A.; Hoffmann, N.; Duft, D.; Leisner, T.

    2012-12-01

    The freezing of supercooled water droplets upon contact with aerosol particles (contact nucleation of ice) is the least understood mechanism of ice formation in atmospheric clouds. Although experimental evidences suggest that some aerosols can be better IN in the contact than in the immersion mode (that is, triggering ice nucleation at higher temperature), no final explanation of this phenomena currently exists. On the other hand, the contact freezing is believed to be responsible for the enhanced rate of secondary ice formation occasionally observed in LIDAR measurements in the cold mixed phase clouds. Recently we have been able to show that the freezing of supercooled droplets electrodynamically levitated in the laminar flow containing mineral dust particles (kaolinite) is a process solely governed by a rate of collisions between the supercooled droplet and the aerosol particles. We have shown that the probability of droplet freezing on a single contact with aerosol particle may differ over an order of magnitude for kaolinite particles having different genesis and morphology. In this presentation we extend the study of contact nucleation of ice and compare the IN efficiency measured for DMA-selected kaolinite, illite and hematite particles. We show that the freezing probability increases towards unity as the temperature decreases and discuss the functional form of this temperature dependence. We explore the size dependence of the contact freezing probability and show that it scales with the surface area of the particles, thus resembling the immersion freezing behavior. However, for all minerals investigated so far, the contact freezing has been shown to dominate over immersion freezing on the short experimental time scales. Finally, based on the combined ESEM and electron microprobe analysis, we discuss the significance of particle morphology and variability of chemical composition on its IN efficiency in contact mode.

  4. Titanic: A Statistical Exploration.

    ERIC Educational Resources Information Center

    Takis, Sandra L.

    1999-01-01

    Uses the available data about the Titanic's passengers to interest students in exploring categorical data and the chi-square distribution. Describes activities incorporated into a statistics class and gives additional resources for collecting information about the Titanic. (ASK)

  5. Academics explore humidity's benefits.

    PubMed

    Mortimer, Dave

    2008-11-01

    The effects of humidification on hospital superbugs are being explored by some of the UK's top academics, in what Dave Mortimer, national sales manager for Vapac Humidity Control, explains are the UK's first such studies. PMID:19044148

  6. Explore and Discover

    NASA Video Gallery

    Train to improve your aerobic and anaerobic fitness by carrying weighted objects in this activity. The Train Like an Astronaut project uses the excitement of exploration to challenge students to se...

  7. Mars Human Exploration Objectives

    NASA Technical Reports Server (NTRS)

    Briggs, Geoff

    1998-01-01

    This paper reviews the objectives and other considerations of Human exploration of Mars. The objectives of human exploration of Mars are: (1) to learn how Mars is similar to, and different from, Earth; (2) to explore possible life, past and present; (3) to discover what Mars is like now from the perspective of Geoscience and geologic history; and (4) how did Mars form and how did its formation differ from Earth. Considerations of human Martian exploration involve: (1) having a capable base laboratory; (2) having long range transportation; (3) having operational autonomy of the crew, and the requirement of the crew to possess a range of new cognitive processes along with easy communications with terrestrial colleagues; and finally (4) creating the human habitat along with human factors which involve more than just survivability.

  8. Mars Exploration Rover Mission

    NASA Technical Reports Server (NTRS)

    Cohen, Barbara A.

    2008-01-01

    This viewgraph presentation reviews the Mars Exploration Rover Mission. The design of the Rover along with the Athena science payload is also described. Photographs of the Gusev Crater and Meridiani rocks are also shown.

  9. More Electrostatic Explorations.

    ERIC Educational Resources Information Center

    Stewart, Gay; Gallai, Ditta

    1998-01-01

    Presents worksheet activities that enable students to explore the concept of electrostatic induction and learn the meaning of grounding. Students build two classic devices, the electrophorus and the leaf electroscope. (DDR)

  10. Abdominal exploration - series (image)

    MedlinePlus

    ... surgical exploration of the abdomen, also called an exploratory laparotomy, may be recommended when there is abdominal ... blunt trauma"). Diseases that may be discovered by exploratory laparotomy include: inflammation of the appendix (acute appendicitis) ...