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Sample records for particle explorer sampex

  1. 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.

  2. SAMPEX science pointing with velocity avoidance. [solar anomalous and magnetospheric particle explorer

    NASA Technical Reports Server (NTRS)

    Frakes, Joseph P.; Henretty, Debra A.; Flatley, Thomas W.; Markley, F. L.; San, Josephine K.; Lightsey, E. G.

    1992-01-01

    The Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) science pointing mode is presented with the additional constraint of velocity avoidance. This constraint has been added in light of the orbital debris and micrometeoroid fluxes that have been revealed by the Long Duration Exposure Facility (LDEF) recovered in January 1990. These fluxes are 50-100 times higher than the flux tables that were used in the September 1988 proposal to NASA for the SAMPEX mission. The SAMPEX Heavey Ion Large Telescope (HILT) sensor includes a flow-through isobutane proportional counter that is susceptible to penetration by orbital debris and micrometeoroids. Thus, keeping the HILT sensor pointed away from the velocity vector, the direction of maximum flux, will compensate for the higher than expected fluxes. Using an orbital debris model and a micrometeoroid model developed at the Johnson Space Center (JSC), and a SAMPEX dynamic simulator developed by the Guidance and Control Branch at the Goddard Space Flight Center (GSFC), an 'optimal' minimum ram angle (the angle between the HILT boresight and the velocity vector) of 90 degrees has been determined. It is optimal in the sense of minimizing the science pointing performance degradation while providing approximately an 89 percent chance of survival for the HILT sensor over a three year period.

  3. An overview of the solar, anomalous, and magnetospheric particle explorer (SAMPEX) mission

    SciTech Connect

    Baker, D.N. . Lab. for Extraterrestrial Physics); Mason, G.M. . Dept. of Physics); Figueroa, O.; Colon, G.; Watzin, J.G.; Aleman, R.M. . Engineering Directorate)

    1993-05-01

    The scientific objective of the NASA Small-class Explorer Mission SAMPEX are 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[degree] 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. 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.

  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. High Latitude Energetic Particle Boundaries: The SAMPEX Database

    NASA Astrophysics Data System (ADS)

    Kanekal, S. G.; Baker, D. N.

    2006-11-01

    The size of the polar cap or the open field line region depends, upon the difference in reconnection rates at the dayside between the IMF and the geomagnetic field, and those occurring in the magnetotail. The dayside merging adds flux to the open field region increasing the polar cap size and the magnetic flux in the lobes of the tail, thereby causing energy to be stored in the magnetosphere. Night side reconnection, geomagnetic storms and substorms dissipate this energy removing flux and shrink the polar cap. The dynamics of the polar cap can therefore be useful in the study of the energy dynamics of the magnetosphere. Energetic particles delineate magnetospheric regions, since their motions are governed by the geomagnetic field. Convection and corotation electric fields control the drift of low energy particles whereas magnetic field gradient and curvature are the dominant factors for higher energy (> ~30 keV) particles. High latitude energetic particle boundaries are related to the polar cap and therefore useful in determining the size of the open field line regions We will provide a long database of energetic particle boundaries in the polar regions using instruments aboard SAMPEX, the first of the Small explorer (SMEX) spacecraft. It was launched on July 3, 1992 into a low earth polar orbit. There are four particle detectors, HILT, LICA, PET and MAST on board which point toward the zenith over the poles of the Earth. These detectors measure electrons, protons and ions ranging in energy from tens of keV to a few MeV. This database will comprise the latitudinal (geographic, magnetic and invariant) and longitudinal (geographic and magnetic local time) positions of energetic particle boundaries in the polar regions. The database will cover a time period from launch to about mid 2004. It will therefore cover a significant portion of the solar cycles 22 and 23. Together with interplanetary data obtainable from public databases, such as the NASA OMNI database the

  7. SAMPEX special pointing mode

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis; Flatley, Thomas W.; Leoutsakos, Theodore

    1995-01-01

    A new pointing mode has been developed for the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) spacecraft. This pointing mode orients the instrument boresights perpendicular to the field lines of the Earth's magnetic field in regions of low field strength and parallel to the field lines in regions of high field strength, to allow better characterization of heavy ions trapped by the field. The new mode uses magnetometer signals and is algorithmically simpler than the previous control mode, but it requires increased momentum wheel activity. It was conceived, designed, tested, coded, uplinked to the spacecraft, and activated in less than seven months.

  8. 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.

  9. 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.

  10. SAMPEX science pointing with velocity avoidance

    NASA Astrophysics Data System (ADS)

    Frakes, Joseph P.; Henretty, Debra A.; Flatley, Thomas W.; Markley, F. L.; San, Josephine K.; Lightsey, E. G.

    The Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) science pointing mode is presented with the additional constraint of velocity avoidance. This constraint has been added in light of the orbital debris and micrometeoroid fluxes that have been revealed by the Long Duration Exposure Facility (LDEF) recovered in January 1990. These fluxes are 50-100 times higher than the flux tables that were used in the September 1988 proposal to NASA for the SAMPEX mission. The SAMPEX Heavey Ion Large Telescope (HILT) sensor includes a flow-through isobutane proportional counter that is susceptible to penetration by orbital debris and micrometeoroids. Thus, keeping the HILT sensor pointed away from the velocity vector, the direction of maximum flux, will compensate for the higher than expected fluxes. Using an orbital debris model and a micrometeoroid model developed at the Johnson Space Center (JSC), and a SAMPEX dynamic simulator developed by the Guidance and Control Branch at the Goddard Space Flight Center (GSFC), an 'optimal' minimum ram angle (the angle between the HILT boresight and the velocity vector) of 90 degrees has been determined. It is optimal in the sense of minimizing the science pointing performance degradation while providing approximately an 89 percent chance of survival for the HILT sensor over a three year period.

  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.; 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.

  12. 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.

  13. 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.

  14. Measurements of the isotopic composition of solar energetic particles with the MAST instrument aboard the SAMPEX spacecraft

    NASA Astrophysics Data System (ADS)

    Williams, Daniel Leroy

    We report measurements of the isotopic composition of solar energetic particles (SEP) as observed in two gradual solar energetic particle events which began on 30 October and 2 November of 1992. These measurements were taken by the Mass Spectrometer Telescope (MAST), a charged-particle telescope on board the SAMPEX satellite in a polar, low-Earth orbit. The elements measured are carbon, nitrogen, oxygen, neon, magnesium and silicon, which are observed over an energy interval of ~15 to 70 MeV per nucleon. These are the first isotopic measurements of silicon, and only the second measurements of the other elements in individual SEP events.SAMPEX has access to interplanetary fluxes of energetic particles during the high latitude portions of its orbit. This access depends on the rigidity of the particles and therefore on their charge to mass ratio. Fortunately, the polar orbit of SAMPEX allows measurement of SEP charge states using the geomagnetic filtering technique, and a previous study reported measurements of the ionic charge states in the same two SEP events studied in this work. This was the first time that charge states of SEPs at these high energies have been measured, and it allows rigidity-dependent biases in the elemental and isotopic composition to be investigated in the present study. This is particularly important since acceleration/transport processes depend on rigidity, and because the observed composition is also affected by the Earth's magnetic field.The MAST instrument measures both elemental and isotopic composition using the [...] technique, which resulted in a typical mass resolution of ~0.24 amu. It was found that during times of high counting rates, the measured mass distributions exhibited high-mass tails. Through computer simulation of the instrument and its particle environment, it was found that these tails are caused by [...] MeV protons which hit the instrument hodoscope in coincidence with the heavy ions of interest. By choosing only data

  15. SAMPEX payload operation control center implementation

    NASA Technical Reports Server (NTRS)

    Mandl, Daniel; Koslosky, Jack; Mahmot, Ron; Rackley, Michael; Lauderdale, Jack

    1993-01-01

    The Solar Anomolous and Magnetospheric Explorer (SAMPEX) satellite was launched in July 1992. It was the first in the NASA Small Explorer (SMEX) series. In building the real-time control center facility, several new mission support challenges had to be met: CCSDS telemetry and command format, 900 Kbps telemetry data, and shorter turn-around time for control center development than previous missions. The SAMPEX Payload Operations Control Ccnter (POCC) was also the first control center for a new satellite to be based on the Transportable Payload Operations Control Center (TPOCC) system architecture and methodology. This approach has both guided the implementation of the SAMPEX control center and provided some of the building blocks. By using the TPOCC architecture to build the SAMPEX POCC, the real-time operations area was miniaturized into one room, whereas previous missions needed multiple large rooms. The development cost of the SAMPEX POCC was reduced from previous missions and will provide for further cost savings in the future SMEX satellites. This paper describes the system as built and some of the enhancements in progress to create this teleoperations environment.

  16. 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.

  17. 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.

  18. Solar Anomalous and Magnetospheric Particle Explorer attitude control electronics box design and performance

    NASA Technical Reports Server (NTRS)

    Chamberlin, K.; Clagett, C.; Correll, T.; Gruner, T.; Quinn, T.; Shiflett, L.; Schnurr, R.; Wennersten, M.; Frederick, M.; Fox, S. M.

    1993-01-01

    The attitude Control Electronics (ACE) Box is the center of the Attitude Control Subsystem (ACS) for the Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) satellite. This unit is the single point interface for all of the Attitude Control Subsystem (ACS) related sensors and actuators. Commands and telemetry between the SAMPEX flight computer and the ACE Box are routed via a MIL-STD-1773 bus interface, through the use of an 80C85 processor. The ACE Box consists of the flowing electronic elements: power supply, momentum wheel driver, electromagnet driver, coarse sun sensor interface, digital sun sensor interface, magnetometer interface, and satellite computer interface. In addition, the ACE Box also contains an independent Safehold electronics package capable of keeping the satellite pitch axis pointing towards the sun. The ACE Box has dimensions of 24 x 31 x 8 cm, a mass of 4.3 kg, and an average power consumption of 10.5 W. This set of electronics was completely designed, developed, integrated, and tested by personnel at NASA GSFC. SAMPEX was launched on July 3, 1992, and the initial attitude acquisition was successfully accomplished via the analog Safehold electronics in the ACE Box. This acquisition scenario removed the excess body rates via magnetic control and precessed the satellite pitch axis to within 10 deg of the sun line. The performance of the SAMPEX ACS in general and the ACE Box in particular has been quite satisfactory.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

    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.

  20. 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.

  1. 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.

  2. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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.

  5. 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).

  6. 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.

  7. SAMPEX observations of the South Atlantic anomaly secular drift during solar cycles 22-24

    NASA Astrophysics Data System (ADS)

    Jones, A. D.; Kanekal, S. G.; Baker, D. N.; Klecker, B.; Looper, M. D.; Mazur, J. E.; Schiller, Q.

    2017-01-01

    It is observed that charged particle intensities are very high near the South Atlantic anomaly (SAA) and are a potential hazard to spacecraft passing through the region. In this study, we examine the secular drift of the SAA location at ˜400-600 km altitude over nearly two solar cycles, using particle count rates to trace the geomagnetic field lines in the region near the SAA. We use data from the Low-Energy Ion Composition Analyzer sensor on board the SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) spacecraft to measure both the longitudinal and latitudinal drifts of the SAA. We find that the longitudinal drift rate is 0.20 ± 0.04° west per year and that the latitudinal drift rate is 0.11 ± 0.01° south per year. These measurements are compared with the IGRF12 (International Geomagnetic Reference Field) model calculations based on an analysis of magnetic field minima in the region of the SAA. Our results, which are in good agreement with model results and prior measurements when declining spacecraft altitude is taken into account, have important space weather implications.

  8. Preliminary SEU analysis of the SAMPEX MIL-STD-1773 space-flight data

    NASA Astrophysics Data System (ADS)

    Crabtree, Christina M.; LaBel, Kenneth A.; Stassinopoulos, E. G.; Miller, Jay T.

    1993-09-01

    The Small Explorer Data System (SEDS) relies heavily on new technologies in the electrical designs. Among the key technologies utilized are fiber optics. The effects of the harsh space radiation environment on these spacecraft components can be quite severe. This paper takes a preliminary look at the single event upset (SEU) data seen during the early portion of SAMPEX flight (launched in July 1992) versus the ground test predictions. The new technologies are addressed along with the error handling abilities of the fiber optic system (MIL-STD-1773). The predicted SAMPEX radiation environment is discussed as well as the methodology of SEU rate prediction utilizing both cosmic ray and proton concerns. A comparison of the flight data to ground test predictions is discussed along with information concerning the significance of where and when the SEUs have occurred.

  9. 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.

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

    PubMed

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

    1996-11-01

    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.

  11. 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.

  12. 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.

  13. 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.

  14. The causes of the hardest electron precipitation events seen with SAMPEX

    NASA Astrophysics Data System (ADS)

    Smith, David M.; Casavant, Eric P.; Comess, Max D.; Liang, Xinqing; Bowers, Gregory S.; Selesnick, Richard S.; Clausen, Lasse B. N.; Millan, Robyn M.; Sample, John G.

    2016-09-01

    We studied the geomagnetic, plasmaspheric, and solar wind context of relativistic electron precipitation (REP) events seen with the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), Proton Electron Telescope (PET) to derive an exponential folding energy E0 for each event. Events with E0< 400 keV peak near midnight, and with increasing E0, the peak magnetic local time (MLT) moves earlier but never peaks as early as the MLT distribution of electromagnetic ion cyclotron (EMIC) waves in the outer belt, and a distinct component near midnight remains. Events with E0>750 keV near dusk (1400 < MLT < 2000) show correlations with solar wind dynamic pressure and proton density, AE index, negative Dst index, and an extended plasmasphere, all supporting an EMIC wave interpretation. Events with 500 keV 500 keV ("hard REP"), we estimate that roughly 45% of the whole population has the distributions of geomagnetic and solar wind parameters associated with EMIC waves, while 55% does not. We hypothesize that the latter events may be caused by current sheet scattering (CSS), which can be mistaken for EMIC wave scattering in that both simultaneously precipitate MeV electrons and keV protons. Since a large number of MeV electrons are lost in the near-midnight hard REP events, and in the large number of E0< 400 keV events that show no dusk-like peak at all, we conclude that CSS should be studied further as a possibly important loss channel for MeV electrons.

  15. 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.

  16. 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.

  17. 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.

  18. Characteristics of Duskside Relativistic Electron Precipitation measured with SAMPEX

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    We will present spectral data from the Proton/Electron Telescope (PET) on SAMPEX that show relativistic electron precipitation with the hardest spectra concentrated in the dusk sector, as observed with a much smaller data set from balloons (Duskside Relativistic Electron Precipitation, or DREP). This is roughly consistent with the favored model of scattering by electromagnetic ion cyclotron (EMIC) waves as the precipitation mechanism. To further test the EMIC wave hypothesis, we compare the local-time distribution of the SAMPEX DREPs with the distribution of EMIC waves studied with GOES at geosynchronous orbit and find a significant shift between the two local time peaks. This statistical comparison is complementary to case studies that show, e.g., DREP occurring simultaneously with proton precipitation, in support of the EMIC hypothesis. We will also show IMAGE EUV data giving the plasmaspheric density at the times and locations of SAMPEX DREP events, testing the expectation that the DREP correspond to enhanced densities (strong plumes) relative to randomly-selected times. Finally, we will show the distribution of the timing of DREP relative to geomagnetic storms and the dependence of the probability of DREP on Kp and the phase of the solar cycle.

  19. 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.

  20. Observations of geomagnetically trapped anomalous cosmic rays by SAMPEX

    SciTech Connect

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

    1996-07-25

    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 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.

  1. 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.}

  2. 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

  3. 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.

  4. The DArk Matter Particle Explorer mission

    NASA Astrophysics Data System (ADS)

    Chang, J.; Ambrosi, G.; An, Q.; Asfandiyarov, R.; Azzarello, P.; Bernardini, P.; Bertucci, B.; Cai, M. S.; Caragiulo, M.; Chen, D. Y.; Chen, H. F.; Chen, J. L.; Chen, W.; Cui, M. Y.; Cui, T. S.; D'Amone, A.; De Benedittis, A.; De Mitri, I.; Di Santo, M.; Dong, J. N.; Dong, T. K.; Dong, Y. F.; Dong, Z. X.; Donvito, G.; Droz, D.; Duan, K. K.; Duan, J. L.; Duranti, M.; D'Urso, D.; Fan, R. R.; Fan, Y. Z.; Fang, F.; Feng, C. Q.; Feng, L.; Fusco, P.; Gallo, V.; Gan, F. J.; Gan, W. Q.; Gao, M.; Gao, S. S.; Gargano, F.; Gong, K.; Gong, Y. Z.; Guo, J. H.; Hu, Y. M.; Huang, G. S.; Huang, Y. Y.; Ionica, M.; Jiang, D.; Jiang, W.; Jin, X.; Kong, J.; Lei, S. J.; Li, S.; Li, X.; Li, W. L.; Li, Y.; Liang, Y. F.; Liang, Y. M.; Liao, N. H.; Liu, Q. Z.; Liu, H.; Liu, J.; Liu, S. B.; Liu, Q. Z.; Liu, W. Q.; Liu, Y.; Loparco, F.; Lü, J.; Ma, M.; Ma, P. X.; Ma, S. Y.; Ma, T.; Ma, X. Q.; Ma, X. Y.; Marsella, G.; Mazziotta, M. N.; Mo, D.; Miao, T. T.; Niu, X. Y.; Pohl, M.; Peng, X. Y.; Peng, W. X.; Qiao, R.; Rao, J. N.; Salinas, M. M.; Shang, G. Z.; Shen, W. H.; Shen, Z. Q.; Shen, Z. T.; Song, J. X.; Su, H.; Su, M.; Sun, Z. Y.; Surdo, A.; Teng, X. J.; Tian, X. B.; Tykhonov, A.; Vagelli, V.; Vitillo, S.; Wang, C.; Wang, Chi; Wang, H.; Wang, H. Y.; Wang, J. Z.; Wang, L. G.; Wang, Q.; Wang, S.; Wang, X. H.; Wang, X. L.; Wang, Y. F.; Wang, Y. P.; Wang, Y. Z.; Wen, S. C.; Wang, Z. M.; Wei, D. M.; Wei, J. J.; Wei, Y. F.; Wu, D.; Wu, J.; Wu, S. S.; Wu, X.; Xi, K.; Xia, Z. Q.; Xin, Y. L.; Xu, H. T.; Xu, Z. L.; Xu, Z. Z.; Xue, G. F.; Yang, H. B.; Yang, J.; Yang, P.; Yang, Y. Q.; Yang, Z. L.; Yao, H. J.; Yu, Y. H.; Yuan, Q.; Yue, C.; Zang, J. J.; Zhang, C.; Zhang, D. L.; Zhang, F.; Zhang, J. B.; Zhang, J. Y.; Zhang, J. Z.; Zhang, L.; Zhang, P. F.; Zhang, S. X.; Zhang, W. Z.; Zhang, Y.; Zhang, Y. J.; Zhang, Y. Q.; Zhang, Y. L.; Zhang, Y. P.; Zhang, Z.; Zhang, Z. Y.; Zhao, H.; Zhao, H. Y.; Zhao, X. F.; Zhou, C. Y.; Zhou, Y.; Zhu, X.; Zhu, Y.; Zimmer, S.

    2017-10-01

    The DArk Matter Particle Explorer (DAMPE), one of the four scientific space science missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Sciences, is a general purpose high energy cosmic-ray and gamma-ray observatory, which was successfully launched on December 17th, 2015 from the Jiuquan Satellite Launch Center. The DAMPE scientific objectives include the study of galactic cosmic rays up to ∼ 10 TeV and hundreds of TeV for electrons/gammas and nuclei respectively, and the search for dark matter signatures in their spectra. In this paper we illustrate the layout of the DAMPE instrument, and discuss the results of beam tests and calibrations performed on ground. Finally we present the expected performance in space and give an overview of the mission key scientific goals.

  5. 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…

  6. 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…

  7. Quantification of the precipitation loss of radiation belt electrons observed by SAMPEX

    NASA Astrophysics Data System (ADS)

    Tu, Weichao; Selesnick, Richard; Li, Xinlin; Looper, Mark

    2010-07-01

    Based on SAMPEX/PET observations, the rates and the spatial and temporal variations of electron loss to the atmosphere in the Earth's radiation belt were quantified using a drift diffusion model that includes the effects of azimuthal drift and pitch angle diffusion. The measured electrons by SAMPEX can be distinguished as trapped, quasi-trapped (in the drift loss cone), and precipitating (in the bounce loss cone). The drift diffusion model simulates the low-altitude electron distribution from SAMPEX. After fitting the model results to the data, the magnitudes and variations of the electron lifetime can be quantitatively determined based on the optimum model parameter values. Three magnetic storms of different magnitudes were selected to estimate the various loss rates of ˜0.5-3 MeV electrons during different phases of the storms and at L shells ranging from L = 3.5 to L = 6.5 (L represents the radial distance in the equatorial plane under a dipole field approximation). The storms represent a small storm, a moderate storm from the current solar minimum, and an intense storm right after the previous solar maximum. Model results for the three individual events showed that fast precipitation losses of relativistic electrons, as short as hours, persistently occurred in the storm main phases and with more efficient loss at higher energies over wide range of L regions and over all the SAMPEX-covered local times. In addition to this newly discovered common feature of the main phase electron loss for all the storm events and at all L locations, some other properties of the electron loss rates, such as the local time and energy dependence that vary with time or locations, were also estimated and discussed. This method combining model with the low-altitude observations provides direct quantification of the electron loss rate, a prerequisite for any comprehensive modeling of the radiation belt electron dynamics.

  8. Quantification of the Precipitation Loss of Radiation Belt Electrons Observed by SAMPEX

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    Based on SAMPEX/PET observations, the rates and the spatial and temporal variations of electron loss to the atmosphere in the Earth’s radiation belt were quantified using a Drift-Diffusion model that includes the effects of azimuthal drifts and pitch angle diffusion. The measured electrons detected by SAMPEX can be distinguished as trapped, quasi-trapped (in the drift loss cone), and precipitating (in the bounce loss cone). The Drift-Diffusion model simulates the low-altitude electron distribution from SAMPEX. After fitting the model results to the data, the magnitudes and variations of the electron lifetime can be quantitatively determined based on the optimum model parameter values. Three magnetic storms of different types of magnitude were selected to estimate the various loss rates of ~0.5 to 3 MeV electrons during different phases of the storm and at L shells ranging from L=3.5 to L=6.5 (L represents the radial distance in the equatorial plane under a dipole field approximation). They are a small storm and a moderate storm in the current solar minimum and an intense storm right after the previous solar maximum. Model results for the three individual events showed that fast precipitation losses of energetic radiation belt electrons, as short as hours, persistently occurred in the storm main phases and with more efficient loss at higher energies, over wide range of L regions and over all the SAMPEX covered local times. In addition to this newly discovered common feature of the main phase electron lifetimes for all the storm events and at all L locations, some other properties of the electron loss rates that vary with time or locations, were also estimated and discussed. This method combining model with the low-altitude observations provides direct quantification of the electron loss rate, a prerequisite for any comprehensive modeling of the radiation belt electron dynamics.

  9. A third radiation zone at relativistic energies observed by SAMPEX HILT during the Bastille Day event

    NASA Astrophysics Data System (ADS)

    Kim, K. C.; Shprits, Y.; Blake, J. B.

    2015-12-01

    During July 2000 geomagnetic storm, known as the Bastille Day storm, SAMPEX HILT observed a strong injection of ~1 MeV electrons into the inner radiation zone (below 2 RE) during the storm main phase. Then during the recovery phase electrons are clearly diffusing inwards and forming a pronounced split-structure encompassing a narrow newly formed slot region around L=3. SAMPEX observations are first compared with electron and proton observations on NOAA POES and HEO to validate that the observed unusual dynamics is not caused by contamination by protons. In this study, we perform the time-dependent 3D Versatile Electron Radiation Belt (VERB) simulations of 1 MeV electron flux evolution and have compared the results with the SAMPEX HILT observations. The result shows that the overall time evolution of the observed split structure is in a good agreement with our model simulations. We find that this new belt at energy of ~1 MeV is resulted from scattering by plasmaspheric hiss to the Earth's atmosphere.

  10. Quantification of the Precipitation Loss of Radiation Belt Electrons Observed by SAMPEX (Invited)

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    Based on SAMPEX/PET observations, the fluxes and the spatial and temporal variations of electron loss to the atmosphere in the Earth’s radiation belt were quantified using a drift-diffusion model that includes the effects of azimuthal drift and pitch angle diffusion. The measured electrons by SAMPEX can be distinguished as trapped, quasi-trapped (in the drift loss cone), or precipitating (in the bounce loss cone), and the model simulates the low-altitude electron distribution from SAMPEX. After fitting the model results to the data, the magnitudes and variations of the electron loss rate can be estimated based on the optimum model parameter values. In this presentation we give an overview of our method and published results, followed by some recent improvements we made on the model, including updating the quantified electron lifetimes more frequently (e.g., every two hours instead of half a day) to achieve smoother variations, estimating the adiabatic effects at SAMPEX’s orbit and their influence on our model results, and calculating the error bar associated with each quantified electron lifetime. This method combining a model with low-altitude observations provides direct quantification of the electron loss rate, as required for any accurate modeling of the radiation belt electron dynamics.

  11. 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…

  12. 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…

  13. NASA's Small Explorer spacecraft - Flight proven, high performance, reliable, and still small

    NASA Technical Reports Server (NTRS)

    Watzin, James G.

    1993-01-01

    NASA's Small Explorer (SMEX) project has developed a series of highly capable small satellites that are being used to support astrophysics and space physics investigations. These satellites, while both small and economical, give up nothing in performance and versatility to the larger satellites developed over the past 15 years within the Explorer program. Innovative engineering and new technology advances have increased the potential scientific return of the SMEX spacecraft to a level comparable to larger carriers. The design has struck a balance between mission risk and cost that has allowed for the development of an extremely capable spacecraft. The first SMEX mission, Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX), has been in orbit since July 1992 and is continuing to perform well. It has proven the merits of this design approach. This paper describes the fundamental strategies and technologies used in developing the design. It outlines the key elements of the system architecture and describes the capabilities and merits of the major subsystems. Major design trade-offs are highlighted. Emphasis is placed on the innovative attitude control system which was developed for the SAMPEX mission. The paper also describes the unique SMEX approach to mission operations.

  14. 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

  15. Low Altitude Validation of Geomagnetic Cutoff Models Using SAMPEX Data

    NASA Astrophysics Data System (ADS)

    Young, S. L.; Kress, B. T.

    2011-12-01

    Single event upsets (SEUs) caused by MeV protons are a concern for satellite operators so AFRL is working to create a tool that can specify and/or forecast SEU probabilities. An important component of the tool's SEU probability calculation will be the local energetic ion spectrum. The portion of that spectrum due to trapped energetic ion population is relatively stable and predictable; however it is more difficult to account for the transient solar energetic particles (SEPs). These particles, which can be ejected from the solar atmosphere during a solar flare or filament eruption or can be energized by coronal mass ejection (CME) driven shocks, can penetrate the Earth's magnetosphere into regions not normally populated by energetic protons. The magnetosphere will provide energy dependent shielding that also depends on its magnetic configuration. During magnetic storms that configuration is modified and the SEP cutoff latitude for a given particle energy can be suppressed up to ~15 degrees equatorward exposing normally shielded regions. As a first step to creating the satellite SEU prediction tool, we are comparing the Smart et al. (Advances in Space Research, 2006) and CISM-Dartmouth (Kress et al., Space Weather, 2010) geomagnetic cutoff tools. While they have provided some of their own validations in the noted papers, our validation will be done consistently between models allowing us to better compare the models.

  16. Interactive data exploration and particle tracking for general circulation models

    NASA Technical Reports Server (NTRS)

    Rosenbaum, R. I.; Peskin, R. L.; Walther, S. S.; Zinn, H. P.

    1995-01-01

    The SCENE environment for interactive visualization of complex data sets is discussed. This environment is used to create tools for graphical exploration of atmospheric flow models. These tools may be extended by the user in a seamless manner, so that no programming is required. A module for accurately tracing field lines and particle trajectories in SCENE is presented. This is used to examine the flowfield qualitatively with streamlines and pathlines and to identify critical points in the velocity field. The paper also describes a visualization tool for general circulation models on which the primary features of the environment are demonstrated.

  17. 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.

  18. The AMPTE CCE Spacecraft. [Active Magnetospheric Particle Tracer Explorer Charge Composition Explorer

    NASA Technical Reports Server (NTRS)

    Dassoulas, J.; Peterson, M. R.; Margolies, D. L.

    1985-01-01

    The flight segment of the Active Magnetospheric Particle Tracer Explorers (AMPTE) Program consisted of three separate spacecraft which were launched 'piggyback' into orbit aboard a Delta 3924 launch vehicle, from Cape Canaveral, FL, on August 16, 1984. The three spacecaft are the Charge Composition Explorer (CCE), built for NASA by the Applied Physics Laboratory of the Johns Hopkins University (APL/JHU); the Ion Release Module (IRM), built in the Federal Republic of Germany; and the United Kingdom Subsatellite (UKS), built in the United Kingdom. This paper describes the CCE Spacecraft design, development, and early performance in orbit.

  19. The AMPTE CCE Spacecraft. [Active Magnetospheric Particle Tracer Explorer Charge Composition Explorer

    NASA Technical Reports Server (NTRS)

    Dassoulas, J.; Peterson, M. R.; Margolies, D. L.

    1985-01-01

    The flight segment of the Active Magnetospheric Particle Tracer Explorers (AMPTE) Program consisted of three separate spacecraft which were launched 'piggyback' into orbit aboard a Delta 3924 launch vehicle, from Cape Canaveral, FL, on August 16, 1984. The three spacecaft are the Charge Composition Explorer (CCE), built for NASA by the Applied Physics Laboratory of the Johns Hopkins University (APL/JHU); the Ion Release Module (IRM), built in the Federal Republic of Germany; and the United Kingdom Subsatellite (UKS), built in the United Kingdom. This paper describes the CCE Spacecraft design, development, and early performance in orbit.

  20. 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.

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

    ScienceCinema

    Brau, James E [University of Oregon

    2016-07-12

    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. 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.

  3. Evidence for Duskside Relativistic Electron Precipitation in the SAMPEX data set in the bounce loss cone

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    We performed an analysis of the SAMPEX archival dataset using spectra computed from the PET (proton electron telescope) detector. A listing of thousands of events from 1998 to 2004 in the bounce loss cone was compiled, where events were initially selected on the basis of having the HILT SSD count rate sufficiently above background, then were subject to further screening. There were found two distinct populations of events, those with soft e-folding spectra less than 200 keV and those with hard e-folding spectra of 500 keV or greater. Although the events with harder energy spectra were fewer in number, the event distribution was seen to be clearly dominated by events occurring on the dusk side (12-24 MLT). These duskside events appear to share characteristics of x-ray bremsstrahlung events observed by balloons and they are typically centered about 1-2 L shell outside of the plasmapause according to the O'Brien and Moldwin (2004) plasmapause model. We will show both detailed data from individual events and a statistical summary of the results. Based on previous balloon observations, EMIC waves have been suggested as a possible scattering mechanism for duskside precipitation. These waves are expected to scatter relativistic electrons in the high density region near the plasmapause. We will examine the location of several case study events relative to the plasmaspheric plume using data from IMAGE EUV.

  4. 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.

  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 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.

  7. Solar Energetic Particle Spectral Breaks

    SciTech Connect

    Mewaldt, R.A.; Cohen, C.M.S.; Labrador, A.W.; Cummings, A.C.; Leske, R.A.; Stone, E.C.; Mason, G.M.; Desai, M.I.; Looper, M.L.; Mazur, J.E.; Haggerty, D.E.; Maclennan, C.G.; Li, G.; Wiedenbeck, M.E.

    2005-08-01

    The five large solar particle events during October-November 2003 presented an opportunity to test shock acceleration models with in-situ observations. We use solar particle spectra of H to Fe ions, measured by instruments on ACE, SAMPEX, and GOES-11, to investigate the Q/M-dependence of spectral breaks in the 28 October 2003 event. We find that the break energies scale as (Q/M)b with b {<=} 1.56 to 1.75, somewhat less than predicted. We also conclude that SEP spectra >100 MeV/nucleon are best fit by a double power-law shape.

  8. Energetic particles and currents - results from Dynamics Explorer

    SciTech Connect

    Burch, J.L.

    1988-05-01

    The suprathermal plasma instruments on DE 1 and DE 2 (high-altitude plasma instrument, low-altitude plasma instrument, and energetic ion composition spectrometer) have provided new data on the distribution functions and composition of plasmas at altitudes from a few hundred to about 23,000 km. Of particular interest are the results that have been obtained on the injection and transport of plasma in the polar cusp, on the upward acceleration of ionospheric ions and electrons, and on the charge carriers of the various high-latitude Birkeland current systems (using independent measurements of the currents by the magnetic field instruments MAG-A and MAG-B). These results and other contributions of the Dynamics Explorer hot plasma and magnetic field measurements to the present understanding of magnetosphere-ionosphere coupling are reviewed in this paper. 90 references.

  9. Energetic particles and currents - Results from Dynamics Explorer

    NASA Astrophysics Data System (ADS)

    Burch, J. L.

    1988-05-01

    The suprathermal plasma instruments on DE 1 and DE 2 (high-altitude plasma instrument, low-altitude plasma instrument, and energetic ion composition spectrometer) have provided new data on the distribution functions and composition of plasmas at altitudes from a few hundred to about 23,000 km. Of particular interest are the results that have been obtained on the injection and transport of plasma in the polar cusp, on the upward acceleration of ionospheric ions and electrons, and on the charge carriers of the various high-latitude Birkeland current systems (using independent measurements of the currents by the magnetic field instruments MAG-A and MAG-B). These results and other contributions of the Dynamics Explorer hot plasma and magnetic field measurements to the present understanding of magnetosphere-ionosphere coupling are reviewed in this paper.

  10. 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

  11. 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.

  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. Exploring results of the possibility on detecting cosmic ray particles by acoustic way

    NASA Technical Reports Server (NTRS)

    Jiang, Y.; Yuan, Y.; Li, Y.; Chen, D.; Zheng, R.; Song, J.

    1985-01-01

    It has been demonstrated experimentally and theoretically that high energy particles produce detectable sounds in water. However, no one has been able to detect an acoustic signal generated by a high energy cosmic ray particle in water. Results show that transient ultrasonic signals in a large lake or reservoir are fairly complex and that the transient signals under water may arise mainly from sound radiation from microbubbles. This field is not explored in detail. Perhaps, the sounds created by cosmic ray particles hide in these ultrasonic signals. In order to develop the technique of acoustic detection, it is most important to make a thorough investigation of these ultrasonic signals in water.

  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. Study of the continuous/diffuse aurora using particle observations from the Dynamics Explorer satellites

    NASA Astrophysics Data System (ADS)

    Sharber, J. R.; Winningham, J. D.

    1988-10-01

    The continuous/diffuse (C/D) aurora and related auroral studies are used as the primary data observations from instruments on the Dynamics Explorer satellites. These satellites carried particle detection instrumentation referred to as the High Altitude Plasma Instrument (HAPI) on the DE-1 and the Low Altitude Plasma Instrument (LAPI) on DE-2, and together provided high resolution spectral and angular measurements of electron and positive ions at altitudes between 500 km and 4 R sub E above the auroral region. The objectives of the research are: (1) to provide a thorough description of the particle populations which produce the quiet and activated continuous/diffuse aurora, (2) to attempt to determine what mechanisms act within the plasma sheet and on supra-auroral field lines to precipitate the continuous/diffuse auroral particles, (3) to attempt to find a simple and effective way to model the effects of this aurora and (4), added during the first year of the contract, applying the Dynamics Explorer database to selective investigations of of the high-latitude auroral regions. Research has included a description of quiet and disturbed diffuse auroral particles, a study of particles and waves in the diffuse aurora, an attempt to determine the mechanisms of the precipitation, and studies of polar arcs, ionization, and convection in the high-latitude regions.

  16. Some design characteristics of the AMPTE turn and orbit change maneuvers. [Active Magnetospheric Particle Tracer Explorers

    NASA Technical Reports Server (NTRS)

    Kechichian, J. A.; Kwong, D. D.

    1985-01-01

    The maneuvers carried out by the Active Magnetospheric Particle Tracer Explorers (AMPTE) including the Charge Composition Explorer (CCE) and the Ion Release Module (IRM) spacecraft are analyzed. Analytic and graphical methods are developed in order to carry out sensitivity analyses that helped design the nominal maneuvers, by taking into account errors in burn initiating time, motor performance, and spin axis pointing. A tradeoff analysis between errors in timing and Delta V magnitude is shown for the IRM orbit transfer, and a technique that allows for the determination of the attitude of spinner spacecraft by way of the observed Doppler shift resulting from an unbalanced turn is investigated.

  17. 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.

  18. 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.

  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. 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.

  1. Exploring Galactic Particle Accelerators with the All-sky Medium Energy Gamma-Ray Observatory (AMEGO)

    NASA Astrophysics Data System (ADS)

    Hays, Elizabeth A.

    2017-08-01

    Observations with the Fermi Large Area Telescope have raised new questions about particle accelerators within the Galaxy, including supernova remnants, pulsar wind nebulae, and novae. What is the origin and mechanism of the extreme, rapid variability seen in the Crab Nebula and how does it connect to longer time-scale hard X-ray variability? Do other young PWNe show this behavior near the synchrotron cutoff energy, which more commonly falls in the MeV band? How does the gamma-ray emission routinely detected from a nova relate to the properties of the binary system and the particle acceleration process occurring in the outburst? Can prompt gamma signals from novae be detected to probe the onset of the thermonuclear runaway explosion? MeV observations will also provide an important extension below the pion decay feature in LAT-detected supernova remnants as well as providing sensitivity to the youngest SNRs in the Galaxy and the LMC. We will explore the impact of medium-energy gamma-ray observations on characterizing known acceleration regions and exploring new, currently inaccessible phenomena.

  2. 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.

  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. 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.

  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 forwardforward shock pairs, results comparing injection energies of the first shock, second shock, and second shock with previous energetic population will be given.

  6. 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.

  7. 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.

  8. FATES: a flexible analysis toolkit for the exploration of single-particle mass spectrometer data

    NASA Astrophysics Data System (ADS)

    Sultana, Camille M.; Cornwell, Gavin C.; Rodriguez, Paul; Prather, Kimberly A.

    2017-04-01

    Single-particle mass spectrometer (SPMS) analysis of aerosols has become increasingly popular since its invention in the 1990s. Today many iterations of commercial and lab-built SPMSs are in use worldwide. However, supporting analysis toolkits for these powerful instruments are outdated, have limited functionality, or are versions that are not available to the scientific community at large. In an effort to advance this field and allow better communication and collaboration between scientists, we have developed FATES (Flexible Analysis Toolkit for the Exploration of SPMS data), a MATLAB toolkit easily extensible to an array of SPMS designs and data formats. FATES was developed to minimize the computational demands of working with large data sets while still allowing easy maintenance, modification, and utilization by novice programmers. FATES permits scientists to explore, without constraint, complex SPMS data with simple scripts in a language popular for scientific numerical analysis. In addition FATES contains an array of data visualization graphic user interfaces (GUIs) which can aid both novice and expert users in calibration of raw data; exploration of the dependence of mass spectral characteristics on size, time, and peak intensity; and investigations of clustered data sets.

  9. Solar Energetic Particles Events and Human Exploration: Measurements in a Space Habitat

    NASA Astrophysics Data System (ADS)

    Narici, L.; Berrilli, F.; Casolino, M.; Del Moro, D.; Forte, R.; Giovannelli, L.; Martucci, M.; Mergè, M.; Picozza, P.; Rizzo, A.; Scardigli, S.; Sparvoli, R.; Zeitlin, C.

    2016-12-01

    Solar activity is the source of Space Weather disturbances. Flares, CME and coronal holes modulate physical conditions of circumterrestrial and interplanetary space and ultimately the fluxes of high-energy ionized particles, i.e., solar energetic particle (SEP) and galactic cosmic ray (GCR) background. This ionizing radiation affects spacecrafts and biological systems, therefore it is an important issue for human exploration of space. During a deep space travel (for example the trip to Mars) radiation risk thresholds may well be exceeded by the crew, so mitigation countermeasures must be employed. Solar particle events (SPE) constitute high risks due to their impulsive high rate dose. Forecasting SPE appears to be needed and also specifically tailored to the human exploration needs. Understanding the parameters of the SPE that produce events leading to higher health risks for the astronauts in deep space is therefore a first priority issue. Measurements of SPE effects with active devices in LEO inside the ISS can produce important information for the specific SEP measured, relative to the specific detector location in the ISS (in a human habitat with a shield typical of manned space-crafts). Active detectors can select data from specific geo-magnetic regions along the orbits, allowing geo-magnetic selections that best mimic deep space radiation. We present results from data acquired in 2010 - 2012 by the detector system ALTEA inside the ISS (18 SPEs detected). We compare this data with data from the detector Pamela on a LEO satellite, with the RAD data during the Curiosity Journey to Mars, with GOES data and with several Solar physical parameters. While several features of the radiation modulation are easily understood by the effect of the geomagnetic field, as an example we report a proportionality of the flux in the ISS with the energetic proton flux measured by GOES, some features appear more difficult to interpret. The final goal of this work is to find the

  10. The impact of solar particle events on radiation risk for human explorers of Mars

    NASA Astrophysics Data System (ADS)

    Gorguinpour, Camron Saul

    This project has examined one specific issue facing human explorers at Mars -- radiation dose from solar particle events (SPEs). While the issue is specific, the work involved in carrying out this study has been truly multidisciplinary. From space physics to modeling the Martian atmosphere to assessing radiation risk to humans, a lot of ground is covered. At each point along the way, efforts were made to clarify the science and assumptions used to derive quantitative estimates and draw meaningful conclusions. The data and analyses provided in this project represent the most comprehensive study of SPE's at a planetary body other than Earth. The analysis includes dose estimates from galactic cosmic radiation. The specific aims of this project are to: (1) Establish a methodology for estimating the fluence of energetic particles at Mars from SPEs; (2) Establish a predictive model to estimate the frequency of SPE occurrence and cumulative SPE fluence received at Mars, as a function of the Solar Cycle; (3) Develop a model to estimate the fluence of energetic particles from SPEs on the Martian surface; (4) Estimate and assess the radiation dose on the Martian surface from SPEs, as compared to galactic cosmic radiation (GCR); and (5) Assess the viability of various types of shielding and mission profiles to mitigate the radiation risk to human explorers on the Martian surface. Some of the conclusions drawn from this study include: (1) The MCP detector onboard MGS ER (and presumably other spacecraft) can serve as an effective detector for high-energy ionizing radiation. (2) Though more work is necessary, it is possible to estimate future solar activity at Earth and Mars based on current solar observations. (3) Spectral information from SPE's at Mars is required to thoroughly assess the radiation environment on the Martian surface. (4) An unshielded astronaut on the Martian surface may face long-term and acute radiation risk from SPE's, depending on the likelihood of their

  11. 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.

  12. particles

    NASA Astrophysics Data System (ADS)

    Xia, Yu; Chen, Zhihong; Zhang, Zhengguo; Fang, Xiaoming; Liang, Guozheng

    2014-05-01

    We explore a facile and nontoxic hydrothermal route for synthesis of a Cu2ZnSnS4 nanocrystalline material by using l-cysteine as the sulfur source and ethylenediaminetetraacetic acid (EDTA) as the complexing agent. The effects of the amount of EDTA, the mole ratio of the three metal ions, and the hydrothermal temperature and time on the phase composition of the obtained product have been systematically investigated. The addition of EDTA and an excessive dose of ZnCl2 in the hydrothermal reaction system favor the generation of kesterite Cu2ZnSnS4. Pure kesterite Cu2ZnSnS4 has been synthesized at 180°C for 12 h from the reaction system containing 2 mmol of EDTA at 2:2:1 of Cu/Zn/Sn. It is confirmed by Raman spectroscopy that those binary and ternary phases are absent in the kesterite Cu2ZnSnS4 product. The kesterite Cu2ZnSnS4 material synthesized by the hydrothermal process consists of flower-like particles with 250 to 400 nm in size. It is revealed that the flower-like particles are assembled from single-crystal Cu2ZnSnS4 nanoflakes with ca. 20 nm in size. The band gap of the Cu2ZnSnS4 nanocrystalline material is estimated to be 1.55 eV. The films fabricated from the hierarchical Cu2ZnSnS4 particles exhibit fast photocurrent responses under intermittent visible-light irradiation, implying that they show potentials for use in solar cells and photocatalysis.

  13. 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

  14. Environmental test of the BGO calorimeter for DArk Matter Particle Explorer

    NASA Astrophysics Data System (ADS)

    Hu, Yi-Ming; Chang, Jin; Chen, Deng-Yi; Guo, Jian-Hua; Zhang, Yun-Long; Feng, Chang-Qing

    2016-11-01

    DArk Matter Particle Explorer (DAMPE) is the first Chinese astronomical satellite, successfully launched on Dec. 17 2015. As the most important payload of DAMPE, the BGO calorimeter contains 308 bismuth germanate crystals, with 616 photomultiplier tubes, one coupled to each end of every crystal. Environmental tests have been carried out to explore the environmental adaptability of the flight model of the BGO calorimeter. In this work we report the results of the vibration tests. During the vibration tests, no visible damage occurred in the mechanical assembly. After random or sinusoidal vibrations, the change of the first order natural frequency of BGO calorimeter during the modal surveys is less than 5%. The shift ratio of Most Probable Value of MIPs changes in cosmic-ray tests are shown, the mean value of which is about -4%. The comparison of results of cosmic-ray tests before and after the vibration shows no significant change in the performance of the BGO calorimeter. All these results suggest that the calorimeter and its structure have passed through the environment tests successfully. Supported by National Natural Science Foundation of China (11203090, 11003051, 11273070) and Strategic Priority Research Program on Space Science of Chinese Academy of Sciences (XDA04040202)

  15. Experimental Results of the Solar Energetic Particle Evens Inside Magnetic Clouds

    NASA Astrophysics Data System (ADS)

    Medina, J.; Hidalgo, M. A.

    2006-08-01

    The modulation effects of the solar ejecta over the solar energetic particle evens (0.5-100 MeV) 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. The experimental data from ACE, SAMPEX, SOHO, Ulysses and WIND satellites are presented, both from MC coincident with Solar particles evens (left figure) and not coincident (right figure). A simple model is proposed to explain this phenomenon. This work is performed inside COST Action 724.

  16. 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.

  17. Exploring uptake and biodistribution of polystyrene (nano)particles in zebrafish embryos at different developmental stages.

    PubMed

    van Pomeren, M; Brun, N R; Peijnenburg, W J G M; Vijver, M G

    2017-09-01

    In ecotoxicology, it is continuously questioned whether (nano)particle exposure results in particle uptake and subsequent biodistribution or if particles adsorb to the epithelial layer only. To contribute to answering this question, we investigated different uptake routes in zebrafish embryos and how they affect particle uptake into organs and within whole organisms. This is addressed by exposing three different life stages of the zebrafish embryo in order to cover the following exposure routes: via chorion and dermal exposure; dermal exposure; oral and dermal exposure. How different nanoparticle sizes affect uptake routes was assessed by using polystyrene particles of 25, 50, 250 and 700nm. In our experimental study, we showed that particle uptake in biota is restricted to oral exposure, whereas the dermal route resulted in adsorption to the epidermis and gills only. Ingestion followed by biodistribution was observed for the tested particles of 25 and 50nm. The particles spread through the body and eventually accumulated in specific organs and tissues such as the eyes. Particles larger than 50nm were predominantly adsorbed onto the intestinal tract and outer epidermis of zebrafish embryos. Embryos exposed to particles via both epidermis and intestine showed highest uptake and eventually accumulated particles in the eye, whereas uptake of particles via the chorion and epidermis resulted in marginal uptake. Organ uptake and internal distribution should be monitored more closely to provide more in depth information of the toxicity of particles. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  18. 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.

  19. Exploration

    USGS Publications Warehouse

    Wilburn, D.R.

    1997-01-01

    This summary of international nonfuel mineral exploration activities for 1996 uses 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 minerals industry direction are drawn from these data.

  20. 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.

  1. Exploration

    USGS Publications Warehouse

    Wilburn, D.R.

    2001-01-01

    Part of an annual review of mines and mineral resources in the U.S. An overview of nonfuel-mineral exploration in 2000 is presented. Principal exploration target was gold exploration in Latin America, Australia, and the U.S. There was a decrease of 18 percent in the exploration budget for gold as compared with the budget for 1999. Statistical information on nonfuel-mineral exploration worldwide is presented, analyzed, and interpreted.

  2. 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.

  3. Exploration

    USGS Publications Warehouse

    Wilburn, D.R.

    2000-01-01

    This summary of international nonfuel mineral exploration activities for 1999 draws upon available data from literature, industry and US Geological Survey (USGS) specialists. The report documents data on exploration budgets by region and commodity and identifies significant mineral discoveries and exploration target areas. It also discusses government programs affecting the mineral exploration industry. And it presents inferences and observations on mineral industry direction based on these data and discussions.

  4. Exploration

    USGS Publications Warehouse

    Wilburn, D.R.

    1998-01-01

    This summary of international nonfuel mineral exploration activities for 1997 draws upon available data from literature, industry and US Geological Sulvey (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.

  5. 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.

  6. Particle and Joule heating of the neutral polar thermosphere in cusp region using atmosphere Explorer-C satellite measurements

    NASA Technical Reports Server (NTRS)

    Griffis, M.; Nisbet, J. S.; Bleuler, E.

    1981-01-01

    It is pointed out that thermospheric heating in the auroral zone and polar cap is of great importance to the variations in the high-latitude neutral wind and the resulting global temperature and densities. The considered investigation is concerned with relating in a quantitative manner the energy inputs from the Joule heating and particle inputs with the thermospheric responses, taking into account the cusp region, and the region of the eastward auroral electrojet. The data used in the investigation were obtained by the Atmosphere Explorer C satellite in late December 1974. Attention is given to electric fields derived from ion drift measurements, electric field strength and particle energy flux measured by the low energy electron experiment for AE-C orbit 4708, electron density contours, Joule heating contours, and height integrated Joule heating and particle energy flux.

  7. Exploration

    USGS Publications Warehouse

    Wilburn, D.R.

    2005-01-01

    The worldwide budget for nonferrous, nonfuel mineral exploration was expected to increase by 58 percent in 2004 from the 2003 budget, according to Metals Economics Group (MEG) of Halifax, Nova Scotia. The increase comes two years after a five-year period of declining spending for mineral exploration (1998 to 2002). Figures suggest a subsequent 27 percent increase in budgeted expenditures from 2002 to 2003. For the second consecutive year, all regional exploration budget estimates were anticipated to increase.

  8. Solar Energetic Particle Spectral Breaks

    NASA Astrophysics Data System (ADS)

    Mewaldt, R.; Cohen, C.; Mason, G.; Desai, M.; Labrador, A.; Lee, M.; Li, G.

    2008-05-01

    A new generation of instruments during solar cycle 23 made it possible to measure solar energetic particle (SEP) energy spectra for many species over a broad energy interval (~0.1 to ~100 MeV/nucleon). These observations revealed that most large SEP events have power-law spectra below a few MeV/nucleon with rather hard spectral indices, followed by spectral steepening at higher energies. These spectral breaks are ordered by species - the spectra of lighter elements break at higher energy/nucleon than those for heavier species. To understand the charge-to-mass (Q/M) dependence of these spectral breaks, we have located the breaks for a range of species (e.g., H, He, C, N, O, Ne, Mg, Si, and Fe) and correlated the break locations with either measured or average Q/M ratios. As of this writing there are results for 13 large SEP events, based on data from ACE, GOES, SAMPEX, and STEREO, and charge state data from SAMPEX and ACE. We find that the location of the breaks is generally well-represented by a power-law in Q/M. This power-law fit can be related to the Q/M- dependence of the interplanetary diffusion coefficient and to the turbulence spectrum of the interplanetary magnetic field. We find that the slope of the deduced turbulence spectra are correlated with Fe/O and the proton fluence. These results support the idea that proton-amplified Alfven waves are generated in large SEP events, as expected for acceleration at parallel shocks.

  9. Exploring the particle nature of dark matter with the All-sky Medium Energy Gamma-ray Observatory (AMEGO)

    NASA Astrophysics Data System (ADS)

    Caputo, Regina; Meyer, Manuel

    2017-08-01

    The era of precision cosmology has revealed that ~80% of the matter in the universe is dark matter. Two leading candidates, motivated by both particle and astrophysics, are Weakly Interacting Massive Particles (WIMPs) and Weakly Interacting Sub-eV Particles (WISPs) like axions and axionlike particles. Both WIMPs and WISPs have distinct gamma-ray signatures. Data from the Fermi Large Area Telescope (Fermi-LAT) continues to be an integral part of the search for these dark matter signatures spanning the 50 MeV to >300 GeV energy range in a variety of astrophysical targets. Thus far, there are no conclusive detections; however, there is an intriguing excess of gamma rays associated with Galactic center (GCE) that could be explained with WIMP annihilation. The angular resolution of the LAT at lower energies makes source selection challenging and the true nature of the detected signal remains unknown. WISP searches using, e.g. supernova explosions, spectra of blazars, or strongly magnetized environments, would also greatly benefit from increased angular and energy resolution, as well as from polarization measurements. To address these, we are developing AMEGO, the All-sky Medium Energy Gamma-ray Observatory. This instrument has a projected energy and angular resolution that will increase sensitivity by a factor of 20-50 over previous instruments. This will allow us to explore new areas of dark matter parameter space and provide unprecedented access to its particle nature.

  10. 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.

  11. Exploration

    USGS Publications Warehouse

    Wilburn, D.R.

    2002-01-01

    Exploration budgets fell for a fourth successive year in 2001. These decreases reflected low mineral commodity prices, mineral-market investment reluctance, company failures and a continued trend of company mergers and takeovers.

  12. 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.

  13. 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.

  14. Exploring postsaddle nuclear dissipation with light-particle multiplicity at high energy

    NASA Astrophysics Data System (ADS)

    Wang, N.; Ye, W.

    2013-05-01

    Based on the stochastic Langevin equation coupled with a statistical decay model, we study the effects of deformation on the accuracy of extracting saddle-to-scission friction (β) by analyzing prescission neutron yields measured in heavy compound nuclei 248Fm, 252Fm, 256Fm, and 251Es. It is shown that accounting for the effect can appreciably reduce the value of β needed to fit data, and a friction value of (11-13)×1021 s-1 is obtained. Furthermore, we find that at low energy the sensitivity of light charged particles (LCPs) to β almost disappears, but the sensitive dependence of neutrons and LCPs on friction is substantially enhanced with increasing excitation energy. Our findings suggest that to obtain precise information of saddle-to-scission nuclear dissipation with particle emission, besides taking into account deformation effects in theoretical calculations, in experiments it is best to populate heavy fissioning systems with high energy.

  15. A Field-Particle Correlation Technique to Explore the Collisionless Damping of Plasma Turbulence

    NASA Astrophysics Data System (ADS)

    Klein, Kristopher

    2016-10-01

    The nature of the dominant mechanisms which damp turbulent electromagnetic fluctuations remains an unanswered question in the study of a variety of collisionless plasma systems. Proposed damping mechanisms can be generally, but not exclusively, classified as resonant, e.g. Landau and cyclotron damping, non-resonant, e.g. stochastic ion heating, and intermittent, e.g. energization via current sheets or magnetic reconnection. To determine the role these mechanisms play in turbulent plasmas, we propose the application of field-particle correlations to time series of single spatial point observations of the type typically measured in the solar wind. This correlation, motivated by the form of the collisionless Vlasov equation, is the time averaged product of the factors comprising the nonlinear field-particle interaction term. The correlation both captures the secular transfer of energy between fields and perturbed plasma distributions by averaging out the conservative oscillatory energy transfer, and retains the velocity space structure of the secular transfer, allowing for observational characterization of the damping mechanism. Field-particle correlations are applied to a set of nonlinear kinetic numerical simulations of increasing complexity, including electrostatic, gyrokinetic, and hybrid Vlasov-Maxwell systems. These correlations are shown to capture the secular energy transfer between fields and particles and distinguish between the mechanisms accessible to the chosen system. We conclude with a discussion of the application of this general technique to data from current and upcoming spacecraft missions, including MMS, DSCOVR, Solar Probe Plus and THOR, which should help in determining which damping mechanisms operate in a variety of heliospheric plasmas. This work was performed in collaboration with Gregory Howes, Jason TenBarge, Nuno Loureiro, Ryusuke Numata, Francesco Valetini, Oreste Pezzi, Matt Kunz, Justin Kasper, and Chris Chen, with support from Grants

  16. 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.

  17. 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.

  18. The Ionic Charge of Solar Energetic Particles with Energies of 0.3-70 MeV per Nucleon

    NASA Astrophysics Data System (ADS)

    Oetliker, M.; Klecker, B.; Hovestadt, D.; Mason, G. M.; Mazur, J. E.; Leske, R. A.; Mewaldt, R. A.; Blake, J. B.; Looper, M. D.

    1997-03-01

    With the three particle sensors Low Energy Ion Composition Analyzer (LICA), Heavy Ion Large Area Proportional Counter Telescope (HILT), and Mass Spectrometer Telescope (MAST) on board the polar-orbiting Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) satellite, the ionic charge of solar energetic particles (SEP) was measured over a wide energy range from 0.3 to 70 MeV per nucleon. For each sensor, the evaluation was performed separately. The results obtained with LICA (0.3-10 MeV per nucleon) and MAST (15-70 MeV per nucleon) were published earlier by Mason et al. and Leske et al., respectively. In this work we present the results of the HILT sensor (7-50 MeV per nucleon) and discuss the combined results of the three instruments. With HILT, the mean ionic charge of SEP was measured for carbon, nitrogen, oxygen, neon, magnesium, silicon, sulfur, argon, calcium, and iron in the energy range 7-50 MeV per nucleon during two consecutive large SEP events in 1992 October-November. The mean ionic charge was inferred from the rigidity-dependent geomagnetic flux cutoff. The coronal temperatures deduced from the mean ionic charges are well in accordance with the value of ~2 × 106 K except for neon and magnesium, as previously reported. The data measured with the three sensors, LICA, HILT, and MAST, agree well and are in accordance with data previously measured at energies below 3 MeV per nucleon (Luhn et al.), except for iron, where we observed a significant energy dependence of the mean charge over the energy range 0.3-70 MeV per nucleon.

  19. 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

  20. 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.

  1. Exploring Ty1 retrotransposon RNA structure within virus-like particles

    PubMed Central

    Purzycka, Katarzyna J.; Legiewicz, Michal; Matsuda, Emiko; Eizentstat, Linda D.; Lusvarghi, Sabrina; Saha, Agniva; Grice, Stuart F. J. Le; Garfinkel, David J.

    2013-01-01

    Ty1, a long terminal repeat retrotransposon of Saccharomyces, is structurally and functionally related to retroviruses. However, a differentiating aspect between these retroelements is the diversity of the replication strategies used by long terminal repeat retrotransposons. To understand the structural organization of cis-acting elements present on Ty1 genomic RNA from the GAG region that control reverse transcription, we applied chemoenzymatic probing to RNA/tRNA complexes assembled in vitro and to the RNA in virus-like particles. By comparing different RNA states, our analyses provide a comprehensive structure of the primer-binding site, a novel pseudoknot adjacent to the primer-binding sites, three regions containing palindromic sequences that may be involved in RNA dimerization or packaging and candidate protein interaction sites. In addition, we determined the impact of a novel form of transposon control based on Ty1 antisense transcripts that associate with virus-like particles. Our results support the idea that antisense RNAs inhibit retrotransposition by targeting Ty1 protein function rather than annealing with the RNA genome. PMID:23093595

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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.

  4. 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

  5. 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.

  6. 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).

  7. 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.

  8. 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.

  9. An update on the Active Magnetospheric Particle Tracer Explorers (AMPTE) program

    NASA Technical Reports Server (NTRS)

    Mcentire, Richard W.

    1987-01-01

    The principles involved in the AMPTE mission's active experiments are discussed together with the role of the AMPTE satellites (the Germany's Ion Release Module, IRM, the United Kingdom Subsatellite, and the U.S Charge Composition Explorer, CCE) in and the results of the ion-release experiments. The AMPTE orbit profile is described, with the times of solar-wind and magnetotail ion releases (two barium and two lithium releases were carried out as the IRM precessed through the magnetosheath) shown schematically. In addition to the results on the Van Allen radiation belts obtained through the ion-release experiments, studies of the radiation belts with the new generation of sensors aboard the CCE and IRM are described.

  10. 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.

  11. 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.

  12. 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.

  13. Using satellite-based measurements to explore spatiotemporal scales and variability of drivers of new particle formation

    EPA Science Inventory

    New particle formation (NPF) can potentially alter regional climate by increasing aerosol particle (hereafter particle) number concentrations and ultimately cloud condensation nuclei. The large scales on which NPF is manifest indicate potential to use satellite-based (inherently ...

  14. Collection efficiency of α-pinene secondary organic aerosol particles explored via light-scattering single-particle aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Shipley Robinson, Ellis; Onasch, Timothy B.; Worsnop, Douglas; Donahue, Neil M.

    2017-03-01

    We investigated the collection efficiency and effective ionization efficiency for secondary organic aerosol (SOA) particles made from α-pinene + O3 using the single-particle capabilities of the aerosol mass spectrometer (AMS). The mean count-based collection efficiency (CEp) for SOA across these experiments is 0.30 (±0.04 SD), ranging from 0.25 to 0.40. The mean mass-based collection efficiency (CEm) is 0.49 (±0.07 SD). This sub-unit collection efficiency and delayed vaporization is attributable to particle bounce in the vaporization region. Using the coupled optical and chemical detection of the light-scattering single-particle (LSSP) module of the AMS, we provide clear evidence that delayed vaporization is somewhat of a misnomer for these particles: SOA particles measured as a part of the AMS mass distribution do not vaporize at a slow rate; rather, they flash-vaporize, albeit often not on the initial impact with the vaporizer but instead upon a subsequent impact with a hot surface in the vaporization region. We also find that the effective ionization efficiency (defined as ions per particle, IPP) decreases with delayed arrival time. CEp is not a function of particle size (for the mobility diameter range investigated, 170-460 nm), but we did see a decrease in CEp with thermodenuder temperature, implying that oxidation state and/or volatility can affect CEp for SOA. By measuring the mean ions per particle produced for monodisperse particles as a function of signal delay time, we can separately determine CEp and CEm and thus more accurately measure the relative ionization efficiency (compared to ammonium nitrate) of different particle types.

  15. The exploration of pharmacokinetic and pharmacodynamic data using interactive three-dimensional graphs, a tool borrowed from particle physics.

    PubMed

    Pollak, P T

    1990-01-01

    Computerized interactive 3-dimensional graphical displays were originally developed to aid in the exploration of multidimensional data from particle physics experiments. This technique can be equally well applied to speed the analysis of multivariate pharmaco-kinetic and pharmacodynamic data. The application of this technique to the results of a drug study demonstrated its effectiveness in providing a rapid overview of the data and in displaying new perspectives on the multivariate data, helping to identify sources of variability within the study. Multiple concentration-time curves from a given administration period can be distinguished within a single plot, using visual cues provided by rotating the display. Simultaneous comparison of large numbers of curves allows rapid evaluation of intersubject variability. Comparing the concentration-time curves from a single subject, each in succession, quickly identifies sources of intra-subject variability. Manipulating the display by a fourth dimensional parameter shows the degree of relationship between the concentration-time curves and associated dynamic variables. Exploratory analysis using such kinematic display software, provides a rapid, visually concrete impression of the relationships present in kinetic and dynamic data before the application of standard statistical routines.

  16. Study of the continuous/diffuse aurora using particle observations from the Dynamics Explorer satellites. Final technical report, 1 January 1985-17 October 1988

    SciTech Connect

    Sharber, J.R.; Winningham, J.D.

    1988-10-17

    The continuous/diffuse (C/D) aurora and related auroral studies are used as the primary data observations from instruments on the Dynamics Explorer satellites. These satellites carried particle-detection instrumentation referred to as the High Altitude Plasma Instrument (HAPI) on the DE-1 and the Low Altitude Plasma Instrument (LAPI) on DE-2, and together provided high-resolution spectral and angular measurements of electron and positive ions at altitudes between 500 km and 4 earth radii above the auroral region. The objectives of the research are: (1) to provide a thorough description of the particle populations which produce the quiet and activated continuous/diffuse aurora, (2) to attempt to determine what mechanisms act within the plasma sheet and on supra-auroral field lines to precipitate the continuous/diffuse auroral particles, (3) to attempt to find a simple and effective way to model the effects of this aurora and (4), added during the first year of the contract, applying the Dynamics Explorer database to selective investigations of of the high-latitude auroral regions. Research has included a description of quiet and disturbed diffuse auroral particles, a study of particles and waves in the diffuse aurora, an attempt to determine the mechanisms of the precipitation, and studies of polar arcs, ionization, and convection in the high-latitude regions.

  17. Exploring the Different Roles of Particle Size in Photoelectrochemical and Photocatalytic Water Oxidation on BiVO4.

    PubMed

    Tan, Hui Ling; Amal, Rose; Ng, Yun Hau

    2016-10-11

    Water oxidation on visible-light-active bismuth vanadate (BiVO4) has commonly been demonstrated to be viable in powder suspension (PS) and particulate photoelectrochemical (PEC) systems. Here, we demonstrate that particle size reduction, which is known to be efficacious in promoting charge carrier extraction and boosting surface active sites, has an opposite effect on BiVO4's photoactivity in the two systems. With three BiVO4 samples of distinctive particle sizes, smaller BiVO4 particle size is shown to be beneficial for enhancing PEC photocurrent generation, but deleterious for photocatalytic O2 evolution on suspended BiVO4. Such contrary effect of particle size in the PEC and PS systems is revealed to be due to the different governing factors of the systems: charge transport in the former and charge separation in the latter. Smaller particle size was found to enrich the interparticle and the particle/FTO substrate contacts which improve charge transport and charge collection efficiency in BiVO4 particulate electrode. On the contrary, larger particle size is necessary for improved photocatalytic O2 evolution because of increased crystallinity and greater band bending, which are essential for charge separation.

  18. MHD-Test Particle Modeling of Prompt 10 MeV Electron Injection Events

    NASA Astrophysics Data System (ADS)

    Hudson, M. K.; Mueller, H. R.; Kress, B. T.; Merkin, V.; Blake, J. B.

    2006-05-01

    An extreme example of impulsive acceleration by radial transport of outer zone electrons into L=2.5 occurred on March 24, 1991, due to a high speed interplanetary shock produced by a Coronal Mass Ejection (CME). The magnetopause was compressed inside the orbit of geosynchronous spacecraft, producing new electron and proton radiation belts with energies > 10 MeV in the normally depleted slot region. Radial transport and energization of electrons occurred on a particle drift time scale of minutes due to the induction electric field launched by rapid magnetopause compression. The new > 10 MeV electron (and proton) belts produced inside geosynchronous orbit on the time scale of interplanetary shock passage persisted for years, as observed by the low altitude SAMPEX satellite in polar orbit, launched in 1992, viewing radiation belt particle precipitation into the atmosphere. A second example of this mechanism has been identified in the SAMPEX PET data at > 10 MeV with the passage of an interplanetary shock on February 21, 1994. While SAMPEX observes precipitation into the loss cone with delay relative to shock passage and storm sudden commencement, the event is clearly seen in situ at L = 2.5 in data from HEO spacecraft 1994-026, with 12 hour orbital resolution. Guiding center test particle simulations have been performed using MHD fields driven by upstream solar wind parameters measured by IMP 8 for the February 21, 1994 injection. It is fortunate that solar wind measurements were available for this storm, unlike March 1991, since it produced the second largest ground-based measurement of dBz/dt of the past solar cycle, mapping to an equatorial plane perturbation and corresponding azimuthal electric field responsible for prompt injection on an electron drift timescale in the March 1991 case, lacking corresponding solar wind input. Results for February 21, 1994 and March 24, 1991 relativistic electron injection events will be compared, along with the 2003 Halloween

  19. Charged-particle telescope experiment on Clementine.

    PubMed

    Baker, D N; Kanekal, S; Blake, J B; Adams, J H

    1995-01-01

    The charged-particle telescope (CPT) onboard the Clementine spacecraft measured the fluxes of energetic protons emitted in solar energetic particle events. Protons in the energy range from 10 to 80 MeV were of greatest interest for radiation effects such as total dose and single event upsets. Energetic electrons were also of interest for spacecraft charging and their contribution to total dose. The lower-energy CPT electron channels (25-500 keV) were mainly of geophysical interest. While orbiting the moon, the CPT observed the wake created by the moon when it blocked the flow of energetic particles in the magnetotail region. The CPT provided opportunities to observe energetic electron bursts during magnetic storms and magnetospheric substorms. CPT data are particularly useful in multispacecraft studies of interplanetary disturbances and their interaction with the magnetosphere. The proton channels on the CPT provided data on solar energetic protons and storm-time protons associated with the passage of an interplanetary shock at 0903 UT on Feb. 21, 1994. Results are compared with those from GOES-7, SAMPEX, and GEOTAIL.

  20. Exploring the effects of particle size and shape on ejecta production in response to low-velocity impacts

    NASA Astrophysics Data System (ADS)

    Dove, A.; Barsoum, C.; Colwell, J. E.

    2016-12-01

    Understanding and predicting the complex behavior of granular material on planetary surfaces requires a combination of complementary experimental and numerical simulations. Such an approach allows us to use experimental results to empirically model the behavior of complex systems, and feed these results into simulations that can be run over a broader range of conditions. Studies of the response of granular systems, particularly planetary regolith and regolith simulants, to low-energy impacts is relevant to surface layers on planetary bodies, including asteroids, small moons, planetesimals, and planetary ring particles. Knowledge of the velocities and mass distributions of dust knocked off of planetary surfaces is necessary to understand the evolution of the upper layers of the soil, and to develop mitigation strategies for transported dust. In addition, the fine particles in the regolith pose an engineering and safety hazard for equipment, experiments, and astronauts working in severe environments. We will present the results of extended testing with a number of combinations of impactor and particle composition and morphology. A spherical glass or brass impactor is used for all experiments, which impacts a particle bed at a few m/s. This study includes three main particle material types - acrylic (used for comparison with initial modeling and previous experiments), glass, and stainless steel. We directly compare the results of these experiments by using 2mm spherical particles of each material type. Additionally, we vary the glass particle sizes between 1-3mm in order to analyze the effect of size on the cratering and ejecta properties. Finally, we varied the stainless steel particle shape from spherical to elongated cylinders with 2mm diameter and 2, 4, and 6 mm lengths. Here, we will focus on the experimental portion of this work - future results will elaborate upon the simulation validation. Interpretation of these results was informed by initial comparisons

  1. Health risks of space exploration: targeted and nontargeted oxidative injury by high-charge and high-energy particles.

    PubMed

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

    2014-03-20

    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. 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. 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. 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.

  2. Exploring the variability of aerosol particle composition in the Arctic: a study from the springtime ACCACIA campaign

    NASA Astrophysics Data System (ADS)

    Young, G.; Jones, H. M.; Darbyshire, E.; Baustian, K. J.; McQuaid, J. B.; Bower, K. N.; Connolly, P. J.; Gallagher, M. W.; Choularton, T. W.

    2015-10-01

    Single-particle compositional analysis of filter samples collected on-board the FAAM BAe-146 aircraft is presented for six flights during the springtime Aerosol-Cloud Coupling and Climate Interactions in the Arctic (ACCACIA) campaign (March-April 2013). Scanning electron microscopy was utilised to derive size distributions and size-segregated particle compositions. These data were compared to corresponding data from wing-mounted optical particle counters and reasonable agreement between the calculated number size distributions was found. Significant variability in composition was observed, with differing external and internal mixing identified, between air mass trajectory cases based on HYSPLIT analyses. Dominant particle classes were silicate-based dusts and sea salts, with particles notably rich in K and Ca detected in one case. Source regions varied from the Arctic Ocean and Greenland through to northern Russia and the European continent. Good agreement between the back trajectories was mirrored by comparable compositional trends between samples. Silicate dusts were identified in all cases, and the elemental composition of the dust was consistent for all samples except one. It is hypothesised that long-range, high-altitude transport was primarily responsible for this dust, with likely sources including the Asian arid regions.

  3. Exploring the role of turbulent acceleration and heating in fractal current sheet of solar flares­ from hybrid particle in cell and lattice Boltzmann virtual test

    NASA Astrophysics Data System (ADS)

    Zhu, B.; Lin, J.; Yuan, X.; Li, Y.; Shen, C.

    2016-12-01

    The role of turbulent acceleration and heating in the fractal magnetic reconnection of solar flares is still not clear, especially at the X-point in the diffusion region. At virtual test aspect, it is hardly to quantitatively analyze the vortex generation, turbulence evolution, particle acceleration and heating in the magnetic islands coalesce in fractal manner, formatting into largest plasmid and ejection process in diffusion region through classical magnetohydrodynamics numerical method. With the development of physical particle numerical method (particle in cell method [PIC], Lattice Boltzmann method [LBM]) and high performance computing technology in recently two decades. Kinetic simulation has developed into an effectively manner to exploring the role of magnetic field and electric field turbulence in charged particles acceleration and heating process, since all the physical aspects relating to turbulent reconnection are taken into account. In this paper, the LBM based lattice DxQy grid and extended distribution are added into charged-particles-to-grid-interpolation of PIC based finite difference time domain scheme and Yee Grid, the hybrid PIC-LBM simulation tool is developed to investigating turbulence acceleration on TIANHE-2. The actual solar coronal condition (L≈105Km,B≈50-500G,T≈5×106K, n≈108-109, mi/me≈500-1836) is applied to study the turbulent acceleration and heating in solar flare fractal current sheet. At stage I, magnetic islands shrink due to magnetic tension forces, the process of island shrinking halts when the kinetic energy of the accelerated particles is sufficient to halt the further collapse due to magnetic tension forces, the particle energy gain is naturally a large fraction of the released magnetic energy. At stage II and III, the particles from the energized group come in to the center of the diffusion region and stay longer in the area. In contract, the particles from non energized group only skim the outer part of the

  4. 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

  5. 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…

  6. 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…

  7. 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.

  8. Using satellite-based measurements to explore spatiotemporal scales and variability of drivers of new particle formation

    NASA Astrophysics Data System (ADS)

    Sullivan, R. C.; Crippa, P.; Hallar, A. G.; Clarisse, L.; Whitburn, S.; Van Damme, M.; Leaitch, W. R.; Walker, J. T.; Khlystov, A.; Pryor, S. C.

    2016-10-01

    New particle formation (NPF) can potentially alter regional climate by increasing aerosol particle (hereafter particle) number concentrations and ultimately cloud condensation nuclei. The large scales on which NPF is manifest indicate potential to use satellite-based (inherently spatially averaged) measurements of atmospheric conditions to diagnose the occurrence of NPF and NPF characteristics. We demonstrate the potential for using satellite-based measurements of insolation (UV), trace gas concentrations (sulfur dioxide (SO2), nitrogen dioxide (NO2), ammonia (NH3), formaldehyde (HCHO), and ozone (O3)), aerosol optical properties (aerosol optical depth (AOD) and Ångström exponent (AE)), and a proxy of biogenic volatile organic compound emissions (leaf area index (LAI) and temperature (T)) as predictors for NPF characteristics: formation rates, growth rates, survival probabilities, and ultrafine particle (UFP) concentrations at five locations across North America. NPF at all sites is most frequent in spring, exhibits a one-day autocorrelation, and is associated with low condensational sink (AOD × AE) and HCHO concentrations, and high UV. However, there are important site-to-site variations in NPF frequency and characteristics, and in which of the predictor variables (particularly gas concentrations) significantly contribute to the explanatory power of regression models built to predict those characteristics. This finding may provide a partial explanation for the reported spatial variability in skill of simple generalized nucleation schemes in reproducing observed NPF. In contrast to more simple proxies developed in prior studies (e.g., based on AOD, AE, SO2, and UV), use of additional predictors (NO2, NH3, HCHO, LAI, T, and O3) increases the explained temporal variance of UFP concentrations at all sites.

  9. 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.; hide

    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.

  10. Exploring the mechanism and kinetics of Fe-Cu-Ag trimetallic particles for p-nitrophenol reduction.

    PubMed

    Yuan, Yue; Yuan, Donghai; Zhang, Yunhong; Lai, Bo

    2017-11-01

    Preparation conditions of Fe-Cu-Ag trimetallic particles were optimized by single-factor and response surface methodology (RSM) batch experiments to obtain high-reactive Fe(0)-based materials for p-nitrophenol (PNP) removal. Under the optimal conditions (i.e., Fe(0) dosage of 34.86 g L(-1), theoretical Cu mass loading of 81.87 mg Cu/g Fe, theoretical Ag mass loading of 1.15 mg Ag/g Fe, and preparation temperature of 52.1 °C), the actual rate constant (kobs) of PNP reduction in 5 min was 1.64 min(-1), which shows a good agreement between the model prediction (1.85 min(-1)) of RSM and the experimental data. Furthermore, the high reactivity of Fe(0)-based trimetals was mainly attributed to the plating order of transition metals (i.e., Ag and Cu). Furthermore, we propose a new theory that the pyramid trimetallic structure of Fe-Cu-Ag could improve the electron transport and create active sites with high electron density at the surface (Ag layer) that could enhance the generation of surface-bonded atomic hydrogen ([H]abs) or the direct reduction of pollutant. Moreover, Fe-Cu-Ag trimetallic particles were characterized by SEM, EDS, and XPS, which also could confirm the proposed theory. In addition, the leached Cu(2+)(<10 μg L(-1)) and Ag(+) (below detection limits) in Fe-Cu-Ag system could be neglected completely, which suggests that Fe-Cu-Ag is reliable, safe, and environment friendly. Therefore, Fe-Cu-Ag trimetallic system would be promising for the removal of pollutants from industrial wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. A small spacecraft mission with large accomplishments

    NASA Astrophysics Data System (ADS)

    Baker, Daniel N.; Mason, Glenn M.; Mazur, Joseph E.

    2012-08-01

    A remarkable era of space research will end soon when, after 20 years of space-based observations, the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) spacecraft will reenter Earth's atmosphere. This will result from the resurgence of the Sun's activity and the related increase of atmospheric drag produced by increasing solar ultraviolet radiation. The best estimate is that SAMPEX will succumb to drag forces (and burn up on reentry) in late September 2012, but this could occur as early as August or as late as December 2012 [see Baker et al., 2012]. SAMPEX has been a pacesetting mission since its inception. It was selected in 1989 for flight as NASA's first spacecraft in the "Small Explorer" (SMEX) program [Baker et al., 1993]. The SMEX program was intended both to accomplish forefront science (at a very affordable cost) as well as to provide a training ground in the best space development practices for a new generation of scientists, engineers, and managers. As its full name suggests, SAMPEX was always intended to perform multiple duties and was geared toward making measurements in space of moderate to very high energy particles [see Baker et al., 1993]. A few of the key contributions made by the SAMPEX program are summarized below.

  12. Quantifying the contribution of microbursts to global electron loss

    NASA Astrophysics Data System (ADS)

    Jones, A. D.; Kanekal, S. G.; Baker, D. N.; Schiller, Q.; Li, W.; Wilson, L. B., III

    2016-12-01

    Electron microbursts, rapid bursts of precipitation, are considered to be an important loss mechanism in the radiation belts. Recent studies have suggested that microbursts can potentially empty the radiation belts on time scales of about a day. We use the Heavy Ion Large Telescope (HILT) instrument and the Proton Electron Telescope (PET) on board the Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) satellite to measure e-folding decay times of global electron fluxes and quantify microburst activity during the global flux decay periods. Furthermore, we use measurements by the Cluster II mission to characterize chorus wave activity occurring in conjunction with SAMPEX microbursts to explore the causal connection between the two.

  13. 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

    USDA-ARS?s Scientific Manuscript database

    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,...

  14. The Gamma-Ray Large-Area Space Telescope: An Astro-Particle Mission to Explore the High-Energy Gamma-Ray Sky

    SciTech Connect

    Spandre, Gloria; /INFN, Pisa

    2009-05-12

    The Gamma Ray Large Area Space Telescope (GLAST) is a space mission that will detect photons from the gamma ray sky, in the rich yet poorly explored high energy band between 20MeV and 1TeV. Main instrument on board is the Large Area Telescope (LAT), a gamma-ray pair-conversion telescope, that will measure direction and energy of incoming photons by means of a very large (11.000 sensors), low pitch (228 {micro}m) Silicon strip Tracker and an imaging CsI e.m. calorimeter, supported in the rejection of charged particles background by an outer, segmented Anti-Coincidence Detector built with plastic scintillators. The superior angular resolution of the LAT, coupled to its very large field of view, results in a sensitivity advance of a factor 30 or more with respect to previously flown instruments. This will allow GLAST to locate currently unresolved gamma ray sources and to detect potential new classes of sources. Study of the residual gamma ray background will have a crucial role in connection to cosmological models, supersymmetric dark matter and relics of exotic particle decay searches. An accurate spectroscopy of all gamma ray emitters will be possible with the high energy resolution of the calorimeter, improving our knowledge of the mechanisms that power the cores of blazars and AGNs, and enabling tens of different pulsar emission models. The GLAST mission will have the instrumental capabilities to locate and analyze sources of cosmic rays and investigate on their acceleration mechanism. As for transient phenomena studies, like the spectacular GRBs, known to be the most energetic natural events, GLAST is in a prominent position. This is due to the minimum detection dead time (<100 {micro}s), typical of the silicon detectors used for the LAT tracker, and to the increased field of view and alert capabilities of the second GLAST instrument, the Gamma Burst Monitor (GBM), essentially conceived as a fast transients trigger for the more accurate observations from the LAT

  15. Modelling the Properties of Rock Coatings Observed by the Mars Exploration Rovers' Alpha Particle X-ray Spectrometer and Hypthesized Environments of Formation

    NASA Astrophysics Data System (ADS)

    Perrett, G.; Clark, B. C.; Squyres, S. W.; Campbell, J. L.

    2016-12-01

    Rock coatings on Mars have been of interest to the scientific community since in situ exploration of the martian surface began in the late 1970s [1-3]. The presence of rock coatings on Mars was speculative until the positive identification of a dark coating on the Adirondack-class rock Mazatzal by the MER Rover Spirit [4]. There has since been evidence for additional rock coatings at both MER and MSL rover sites [5]. These coatings are primarily Cl-rich, which suggests aqueous activity, and their formation may be common in the martian equatorial region [6]. An important objective to better understanding these coatings and their influence on geochemical data sets is to determine their thickness and various other properties [3]. For this work additional coated rocks have been identified in the MER alpha particle X-ray spectrometer (APXS) data set [7]. Using the APXS bulk chemistry for both brushed (dust-free) and abraded (coating-free) measurements on the identified targets the thicknesses, area coverage, and coating compositions have been modelled. The modelling results for the well-studied Mazatzal coating will be compared to previous studies that report thickness [8] and compositional enrichments [4] and environments of formation will be hypothesized. The formation age of the Mazatzal coating is poorly constrained but it could have conceivably formed over a period spanning much of martian history. References: [1] Binder, A.B. et al. (1977), Journal of Geophysical Research, 82:28, 4439-4451;[2] Strickland, E.L. et al. (1979), 10th LPSC, 3, 3055-3077;[3] Guinness, E.A. et al. (1996), 27th LPSC, 27, 471-472;[4] Haskin, L. A. et al. (2005), Nature, 436, 66-69;[5] Lanza, N. et al (2016), Geophysical Research Letters, 43;[6] Clark, B.C. and R. Gellert (2016), 79th Annual Meeting of the Meteoritical Society, #6079;[7] http://pds-geosciences.wustl.edu/missions/mer/mer_apxs_oxide.htm;[8] Fleischer, I. et al (2008), Hyperfine Interact, 186, 193-198.

  16. 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

  17. Design Concept for the High Energy Particle Sensor (HEPS) for NPOESS

    NASA Astrophysics Data System (ADS)

    Connell, J.; Lopate, C.; McKibben, R. B.; Bodet, D. L.; Frost, C.; Gaidos, J.; Needell, J. J.; Widholm, M.

    2005-12-01

    The High Energy Particle Sensor (HEPS), an instrument in the Space Environment Sensor Suite (SESS) on the National Polar-orbiting Operational Environmental Satellite System (NPOESS), will measure protons and He from 10 MeV/n to > 300 MeV/u and heavier ions through Ni at corresponding energies with a geometrical factor of ~1 cm2 ster. It will thus provide useful data on Solar Energetic Particles (SEP), Galactic Cosmic Rays (GCR) and Anomalous Cosmic Rays (ACR). In particular, HEPS is designed so as not to saturate at the highest fluxes of SEPs thus far observed. With the NPOESS polar orbit, HEPS can use the geomagnetic field to study the charge states of the different particle populations, as previously demonstrated on the SAMPEX mission. For example, GRCs are fully stripped, ACRs are mainly singly charged while SEPs are partially stripped. The charge state of SEPs is a diagnostic of the ion source population. HEPS will be based on the Angle Detecting Inclined Sensors (ADIS) system. A prioritized sample of events will be pulse-height analyzed and processed on-board. Owing to the simplicity of the ADIS analysis, events will be identified by charge and binned on-board by the HEPS central processor unit for telemetry to the ground. HEPS will have single element resolution with sigma < 0.25 e.

  18. Natural inflation: Particle physics models, power-law spectra for large-scale structure, and constraints from the Cosmic Background Explorer

    NASA Astrophysics Data System (ADS)

    Adams, Fred C.; Bond, J. Richard; Freese, Katherine; Frieman, Joshua A.; Olinto, Angela V.

    1993-01-01

    We discuss the particle physics basis for models of natural inflation with pseudo Nambu-Goldstone bosons and study the consequences for large-scale structure of the nonscale-invariant density fluctuation spectra that arise in natural inflation and other models. A pseudo Nambu-Goldstone boson, with a potential of the form V(φ)=Λ4[1+/-cos(φ/f)], can naturally give rise to an epoch of inflation in the early Universe, if f~MPl and Λ~MGUT. Such mass scales arise in particle physics models with a gauge group that becomes strongly interacting at the grand unified theory scale. We work out a specific particle physics example based on the multiple gaugino condensation scenario in superstring theory. We then study the cosmological evolution of and constraints upon these inflation models numerically and analytically. To obtain sufficient inflation with a probability of order 1 and a high enough post-inflation reheat temperature for baryogenesis, we require f>~0.3MPl. The primordial density fluctuation spectrum generated by quantum fluctuations in φ is a non-scale-invariant power law P(k)~kns, with ns~=1-(M2Pl/8πf2) leading to more power on large length scales than the ns=1 Harrison-Zeldovich spectrum. (For the reader primarily interested in large-scale structure, the discussion of this topic is presented in Sec. IV and is intended to be nearly self-contained.) We pay special attention to the prospects of using the enhanced power to explain the otherwise puzzling large-scale clustering of galaxies and clusters and their flows. We find that the standard cold dark matter (CDM) model with 0<~ns<~0.6 could in principle explain these data. However, the microwave background anisotropies recently detected by the Cosmic Background Explorer (COBE) imply such low primordial amplitudes for these CDM models (that is, bias factors b8>~2 for ns<~0.6) that galaxy formation would occur too late to be viable and the large-scale galaxy velocities would be too small. In fact, combining the

  19. 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.

  20. Solar Energetic Particle Trapping During Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Hudson, M.; Kress, B.; Blake, J. B.; Mazur, J.

    2007-12-01

    The prompt trapping of Solar Energetic Particles (SEPs) in the inner magnetosphere inside of L = 4 has been reported, including protons and heavier ions, in association with high speed interplanetary shocks and Storm Sudden Commencements (SSCs). These observations include the Bastille Day 2000 CME-driven storm as well as two in November 2001, which produced a long-lived new proton belt, as well as trapping of heavy ions up to Fe in all three cases. A survey of such events around the most recent solar maximum, including high altitude measurements from Polar, HEO and ICO satellites along with low altitude measurements from SAMPEX, indicates similarities to the well-studied March 24, 1991 SSC event. In this event, electrons and protons in drift resonance with a magnetosonic impulse were transported radially inward, requiring a source population which is multi-MeV at geosynchronous. A requirement for such shock-induced acceleration is a high-speed CME- shock at 1 AU, which launches a perturbation with comparable velocity inside the magnetosphere. Secondly, there must be a source population which is drift-resonant with the impulse. The CME-shock itself is a source of solar energetic particles, both protons and heavy ions, with higher fluxes and harder spectra associated with faster moving CMEs. A 3D Lorentz integration of SEP trajectories in electric and magnetic fields taken from the Lyon-Fedder-Mobarry (LFM) global MHD model, using solar wind input parameters from spacecraft measurements upstream from the bow shock, has been carried out for two November, 2001 SEP trapping events, and a CME-shock associated with the Halloween 2003 storm period, 29 October, which transported outer zone electrons and trapped solar energetic electrons into around L = 2.5, with little effect on SEPs. These results indicate that an enhancement in solar wind dynamic pressure for these events plays a role in the observed injection of ions (and electrons) to low L-values, as does the extent of

  1. Fast injection of the relativistic electrons into the inner zone and the formation of the split-zone structure during the Bastille Day storm in July 2000

    NASA Astrophysics Data System (ADS)

    Kim, Kyung-Chan; Shprits, Yuri Y.; Blake, J. Bernard

    2016-09-01

    During the July 2000 geomagnetic storm, known as the Bastille Day storm, Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX)/Heavy Ion Large Telescope (HILT) observed a strong injection of 1 MeV electrons into the slot region (L 2.5) during the storm main phase. Then, during the following month, electrons were clearly seen diffusing inward down to L = 2 and forming a pronounced split structure encompassing a narrow, newly formed slot region around L = 3. SAMPEX observations are first compared with electron and proton observations on HEO-3 and NOAA-15 to validate that the observed unusual dynamics was not caused by proton contamination of the SAMPEX instrument. The time-dependent 3-D Versatile Electron Radiation Belt (VERB) simulation of 1 MeV electron flux evolution is compared with the SAMPEX/HILT observations. The results show that the VERB code predicts overall time evolution of the observed split structure. The simulated split structure is produced by pitch angle scattering into the Earth atmosphere of 1 MeV electrons by plasmaspheric hiss.

  2. 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.

  3. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-06-01

    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.

  5. Teaching German Modal Particles.

    ERIC Educational Resources Information Center

    Rosler, Dietmar

    1982-01-01

    Believes modern linguistics has done little to explore German modal particles because by focusing on sentences as the basic category for linguistic thinking these words did not seem to matter. Describes model which gives students experience with these particles in meaningful communication. (Author/BK)

  6. Teaching German Modal Particles.

    ERIC Educational Resources Information Center

    Rosler, Dietmar

    1982-01-01

    Believes modern linguistics has done little to explore German modal particles because by focusing on sentences as the basic category for linguistic thinking these words did not seem to matter. Describes model which gives students experience with these particles in meaningful communication. (Author/BK)

  7. 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

  8. Exploring sialic acid receptors-related infection behavior of avian influenza virus in human bronchial epithelial cells by single-particle tracking.

    PubMed

    Wang, Zhi-Gang; Liu, Shu-Lin; Zhang, Zhi-Ling; Tian, Zhi-Quan; Tang, Hong-Wu; Pang, Dai-Wen

    2014-07-09

    Human respiratory tract epithelial cells are the portals of human infection with influenza viruses. However, the infection pathway of individual avian influenza viruses in human respiratory cells remains poorly reported so far. The single-particle tracking technique (SPT) is a powerful tool for studying the transport mechanism of biomolecules in live cells. In this work, we use quantum dots to label avian influenza H9N2 virus and elaborate on the infection mechanism of the virus in human bronchial epithelial (HBE) cells using a three-dimensional SPT technique. We have found that the H9N2 virus can infect HBE cells directly and the virus infection follows an actin filament- and microtubule-dependent process with a three-stage pattern. The transport behaviors show a high degree of consistency between the sialic acid receptors and the influenza virus. Real-time SPT provides dynamic evidence of the sialic acid receptors-related infection behavior of the avian influenza virus in live cells. The study of the influence of sialic acid receptors on virus infection may contribute to a better understanding of the cross-species transmission of the avian influenza virus. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. ELUCID—Exploring the Local Universe with the Reconstructed Initial Density Field. I. Hamiltonian Markov Chain Monte Carlo Method with Particle Mesh Dynamics

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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 -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-1 at high z and to k ~ 3.4 h Mpc-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.

  10. 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.

  11. 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.

  12. Active Magnetospheric Particle Tracing Explorers (AMPTE).

    DTIC Science & Technology

    1985-02-07

    0 0C0D 0 0 0 C3 01) 00 0 O C60 -, 0 ~ 0 *" r, C- ’r) SZ9 LO SSZ h WWI 31dWtj h861 Ill d3S h8 Nnu 01*8 U01 D lISWAI 0 I.nI7 cmc fs ow Jn m...3lO3NJOWdAO NOWi)T13 -00 SZ LO SSZ hG WWI 3idWU hG61 @II d3S ~ZOlh ZO 86Z tiG Nflw 900wu1 t*1OI AD Jli!SW3AINl in =r M N -0 CD OD W~ CO Ifr M N -0 ----- 00...AiIS3AINl CD I ~ II 1111 1 lCD * 13 (D 0npW fd W P ic 3c (V - * 00 9S 60 h9Z hQ 1W 31dWUh910d3 zzOthe zO 96 he NAu SOOfWI b314D 3O )dISWJ3AiNf fLn V M’ N

  13. Particle separation

    DOEpatents

    Moosmuller, Hans [Reno, NV; Chakrabarty, Rajan K [Reno, NV; Arnott, W Patrick [Reno, NV

    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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. Exploration review

    USGS Publications Warehouse

    Wilburn, D.R.

    2007-01-01

    This summary of international mineral exploration activities for 2006 draws upon available information from literature, industry and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analysis of the mineral industry based upon these data.

  19. Exploration review

    USGS Publications Warehouse

    Wilburn, D.R.; Bourget, M.R.

    2010-01-01

    This summary of international mineral exploration activities for the year 2009 draws upon information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on industry exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analyses of exploration activities by the mineral industry based upon these data.

  20. Exploration review

    USGS Publications Warehouse

    Wilburn, D.R.

    2009-01-01

    This summary of international mineral exploration activities for 2008 draws upon available information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry, and presents analyses of exploration activities by the mineral industry based upon these data.

  1. Exploration review

    USGS Publications Warehouse

    Wilburn, D.R.; Vasil, R.L.; Nolting, A.

    2011-01-01

    This summary of international mineral exploration activities for the year 2010 draws upon available information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analyses of exploration activities performed by the mineral industry.

  2. 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.

  3. 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.

  4. Particle separator

    DOEpatents

    Hendricks, Charles D.

    1990-01-01

    Method and apparatus (10) are provided for separating and classifying particles (48,50,56) by dispersing the particles within a fluid (52) that is upwardly flowing within a cone-shaped pipe (12) that has its large end (20) above its small end (18). Particles of similar size and shape (48,50) migrate to individual levels (A,B) within the flowing fluid. As the fluid is deflected by a plate (42) at the top end of the pipe (12), the smallest particles are collected on a shelf-like flange (40). Ever larger particles are collected as the flow rate of the fluid is increased. To prevent particle sticking on the walls (14) of the pipe (12), additional fluid is caused to flow into the pipe (12) through holes (68) that are specifically provided for that purpose. Sticking is further prevented by high frequency vibrators (70) that are positioned on the apparatus (10).

  5. 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.

  6. 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.

  7. 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.

  8. New Estimates of Inferred Ionic Charge States for Solar Energetic Particle Events with ACE and STEREO

    NASA Astrophysics Data System (ADS)

    Labrador, A. W.; Sollitt, L. S.; Cohen, C. M.; Cummings, A. C.; Leske, R. A.; Mason, G. M.; Mewaldt, R. A.; Stone, E.; von Rosenvinge, T. T.; Wiedenbeck, M. E.

    2012-12-01

    Solar energetic particle (SEP) mean ionic charge states can depend on source temperatures and populations (e.g. seed populations) and conditions during acceleration and transport such as stripping. Multi-spacecraft observations of charge states from widely separated spacecraft may reveal evidence for seed populations that vary with longitude. In this presentation, we report new estimates of inferred high energy ionic charge states using the Sollitt et al. (2008) method that fits SEP energy-dependent decay times for SEP event elements to derive mean charge states. In the method, intensity decay times during SEP events are fitted for each element for various energies, and then the energy dependence of the decay times is fitted for each element. Finally, charge-to-mass ratios relative to that of a calibration element (carbon in this case) are obtained, and when Q(C)=5.9 is assumed for calibration, mean charge states for other elements can be inferred. Previously, ACE/SIS and ACE/ULEIS data were applied to three SEP events (Nov. 6, 1997; Nov. 4, 2001; Apr. 21, 2002) with this method, and last year, we reported new results for the Dec. 6, 2006 SEP event compatible with SAMPEX/MAST results. Additional work continues to generalize and extend the software to use publicly available online data from ACE and the two STEREO spacecraft. Energy ranges are those covered by the instruments on ACE (e.g. reference element C at <.1 MeV/nuc from ULEIS to ~64 MeV/nuc from SIS) and on STEREO (e.g. C at 3.2 - 33 MeV/nuc from LET). Initial candidate SEP events for multi-spacecraft charge state estimates are those of Mar. 8, 2011, Mar. 21, 2011, Jan. 24, 2012, and Mar. 4, 2012. Results from events observed by single spacecraft may also be reported.

  9. 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.

  10. 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.

  11. Particle preconcentrator

    DOEpatents

    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

    DOEpatents

    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.

  13. 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.

  14. Exploration Review

    USGS Publications Warehouse

    Wilburn, D.R.; Stanley, K.A.

    2013-01-01

    This summary of international mineral exploration activities for 2012 draws upon information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analyses of exploration activities performed by the mineral industry. Three sources of information are reported and analyzed in this annual review of international exploration for 2012: 1) budgetary statistics expressed in U.S. nominal dollars provided by SNL Metals Economics Group (MEG) of Halifax, Nova Scotia; 2) regional and site-specific exploration activities that took place in 2012 as compiled by the USGS and 3) regional events including economic, social and political conditions that affected exploration activities, which were derived from published sources and unpublished discussions with USGS and industry specialists.

  15. Participatory Exploration

    NASA Image and Video Library

    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'...

  16. 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)

  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. Exploration review

    USGS Publications Warehouse

    Wilburn, D.R.; Rapstine, T.D.; Lee, E.C.

    2012-01-01

    This summary of international mineral exploration activities for the year 2011 draws upon available information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. This summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents surveys returned by companies primarily focused on precious (gold, platinum-group metals and silver) and base (copper, lead, nickel and zinc) metals.

  19. Exploration review

    USGS Publications Warehouse

    Wilburn, D.R.

    2008-01-01

    This summary of international mineral exploration activities for the year 2007 draws upon available information from industry, literature and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analysis of the mineral industry based upon these data.

  20. Exploration review

    USGS Publications Warehouse

    Wilburn, D.R.

    2006-01-01

    This summary of international mineral exploration activities for the year 2005 draws upon available information from literature, industry and U.S. Geological Survey (USGS) specialists. It provides data on exploration budgets by global region and mineral commodity and identifies significant mineral discoveries and exploration target areas. It also discusses government programs affecting the mineral exploration industry and presents analysis of the mineral industry based on these data.

  1. Modeling of dielectrophoretic particle motion: Point particle versus finite-sized particle.

    PubMed

    Çetin, Barbaros; Öner, S Doğan; Baranoğlu, Besim

    2017-06-01

    Dielectrophoresis (DEP) is a very popular technique for microfluidic bio-particle manipulation. For the design of a DEP-based microfluidic device, simulation of the particle trajectory within the microchannel network is crucial. There are basically two approaches: (i) point-particle approach and (ii) finite-sized particle approach. In this study, many aspects of both approaches are discussed for the simulation of direct current DEP, alternating current DEP, and traveling-wave DEP applications. Point-particle approach is implemented using Lagrangian tracking method, and finite-sized particle is implemented using boundary element method. The comparison of the point-particle approach and finite-sized particle approach is presented for different DEP applications. Moreover, the effect of particle-particle interaction is explored by simulating the motion of closely packed multiple particles for the same applications, and anomalous-DEP, which is a result of particle-wall interaction at the close vicinity of electrode surface, is illustrated. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. 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.

  3. 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.

  4. Auroral particles

    NASA Astrophysics Data System (ADS)

    Evans, David S.

    1987-06-01

    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.

  5. 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.

  6. Exploration review

    USGS Publications Warehouse

    Wilburn, D.R.

    2004-01-01

    The worldwide budget for nonfuel mineral exploration was expected to increase by 27 percent in 2003 from the 2002 budget, according to the Metals Economics Group (MEG) of Halifax, Nova Scotia. The increase comes after five years of declining spending for mineral exploration.

  7. 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…

  8. 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.

  9. Stable particles

    SciTech Connect

    Samios, N.P.

    1993-12-31

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc.

  10. 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

  11. SAMPEX measurements of heavy ions trapped in the magnetosphere

    SciTech Connect

    Cummings, J.R.; Cummings, A.C.; Mewaldt, R.A.; Selesnick, R.S.; Stone, E.C. ); Rosenvinge, T.T. von ); Blake, J.B. )

    1993-12-01

    New observations of >15 MeV/nuc trapped heavy ions with Z [ge] 2 have been made by the S AMPEX spacecraft in low polar orbit. The composition of these ions, which are located primarily around L = 2, is dominated by He, N, O, and Ne. The N, O, and Ne ions are apparently trapped anomalous cosmic rays,'' while the origin of the trapped He flux is presently uncertain. These ions can affect the rate of single-event upsets (SEUs) in spacecraft hardware.

  12. Particle Geophysics

    NASA Astrophysics Data System (ADS)

    Tanaka, Hiroyuki K. M.

    2014-05-01

    Geophysics research has long been dominated by classical mechanics, largely disregarding the potential of particle physics to augment existing techniques. The purpose of this article is to review recent progress in probing Earth's interior with muons and neutrinos. Existing results for various volcanological targets are reviewed. Geoneutrinos are also highlighted as examples in which the neutrino probes elucidate the composition of Earth's deep interior. Particle geophysics has the potential to serve as a useful paradigm to transform our understanding of Earth as dramatically as the X-ray transformed our understanding of medicine and the body.

  13. 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

  14. 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.

  15. Airborne Particles.

    ERIC Educational Resources Information Center

    Ojala, Carl F.; Ojala, Eric J.

    1987-01-01

    Describes an activity in which students collect airborne particles using a common vacuum cleaner. Suggests ways for the students to convert their data into information related to air pollution and human health. Urges consideration of weather patterns when analyzing the results of the investigation. (TW)

  16. 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.

  17. 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.

  18. Space Exploration

    NASA Technical Reports Server (NTRS)

    McGrath, Melissa A.

    2007-01-01

    Space exploration is an endeavor that has universal appeal, is far reaching in its consequences, crossing borders and spanning intellectual disciplines from art to literature to mathematics, with a purpose and reach that can potentially unite. To enhance awareness and strengthen cooperation within the space community, and provide inspiration for new activities, Dr. McGrath will provide a brief glimpse into a few of the exciting space exploration activities currently being undertaken by NASA.

  19. 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.

  20. 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.

  1. Particle classifier

    SciTech Connect

    Etkin, B.

    1987-04-14

    This patent describes a classifier for particulate material comprising a housing having an inlet to receive a classifying air flow flowing in a given direction, collection means downstream of the inlet to receive material classified by the air flow, and material introduction means intermediate the inlet and the collection means to introduce particles entrained in a secondary air stream into the housing in a direction other than the given direction. The material introduction means includes a material outlet aperture in a wall of the housing extending generally perpendicular to the given direction, conveying means to convey material and the secondary air stream to the material outlet and diverting means to divert the secondary air stream to a direction generally parallel to the classifying air flow flowing in the given direction. The diverting means includes a surface extending downstream from the outlet and adjacent thereto and being dimensioned to divert the secondary airstream by a Coanda effect generally parallel to the given direction and thereby segregate the secondary air/stream from the particles and permit continued movement of the particles along predictable trajectories.

  2. 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.

  3. 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…

  4. 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…

  5. 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…

  6. Exploring Fractals.

    ERIC Educational Resources Information Center

    Dewdney, A. K.

    1991-01-01

    Explores the subject of fractal geometry focusing on the occurrence of fractal-like shapes in the natural world. Topics include iterated functions, chaos theory, the Lorenz attractor, logistic maps, the Mandelbrot set, and mini-Mandelbrot sets. Provides appropriate computer algorithms, as well as further sources of information. (JJK)

  7. Exploring Fractals.

    ERIC Educational Resources Information Center

    Dewdney, A. K.

    1991-01-01

    Explores the subject of fractal geometry focusing on the occurrence of fractal-like shapes in the natural world. Topics include iterated functions, chaos theory, the Lorenz attractor, logistic maps, the Mandelbrot set, and mini-Mandelbrot sets. Provides appropriate computer algorithms, as well as further sources of information. (JJK)

  8. Exploring maps

    USGS Publications Warehouse

    ,

    1993-01-01

    Exploring Maps is an interdisciplinary set of materials on mapping for grades 7-12. Students will learn basic mapmaking and map reading skills and will see how maps can answer fundamental geographic questions: "Where am I?" "What else is here?" "Where am I going?"

  9. 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.

  10. Martian Particle

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image of Martian soil was taken by the Phoenix Lander's atomic force microscope on Sol 74 of the mission, which began on May 25, 2008. This image of a flat, smooth-surfaced particle is consistent with the appearance of soil from Earth containing the mineral phyllosilicate.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

  11. 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…

  12. 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…

  13. Human Exploration of Phobos

    NASA Technical Reports Server (NTRS)

    Abercromby, Andrew F. J.; Chappell, Steven P.; Gernhardt, Michael L.; Lee, David E.; Howe, A. Scott

    2015-01-01

    This study developed, analyzed, and compared mission architectures for human exploration of Mars' Moons within the context of an Evolvable Mars Campaign. METHODS: All trades assumed conjunction class missions to Phobos (approximately 500 days in Mars system) as it was considered the driving case for the transportation architecture. All architectures assumed that the Mars Transit Habitat would remain in a High Mars Orbit with crewmembers transferring between HMO and Phobos in a small crew taxi vehicle. A reference science / exploration program was developed including performance of a standard set of tasks at 55 locations on the Phobos surface. Detailed EVA timelines were developed using realistic flight rules to accomplish the reference science tasks using exploration systems ranging from jetpacks to multi-person pressurized excursion vehicles combined with Phobos surface and orbital (L1, L4/L5, 20km Distant Retrograde Orbit) habitat options. Detailed models of propellant mass, crew time, science productivity, radiation exposure, systems and consumables masses, and other figures of merit were integrated to enable quantitative comparison of different architectural options. Options for pre-staging assets using solar electric propulsion (SEP) vs. delivering all systems with the crew were also evaluated. Seven discrete mission architectures were evaluated. RESULTS: The driving consideration for habitat location (Phobos surface vs. orbital) was radiation exposure, with an estimated reduction in cumulative mission radiation exposure of up to 34% (vs. Mars orbital mission) when the habitat is located on the Phobos surface, compared with only 3-6% reduction for a habitat in a 20km DRO. The exploration utility of lightweight unpressurized excursion vehicles was limited by the need to remain within 20 minutes of Solar Particle Event radiation protection combined with complex GN&C systems required by the non-intuitive and highly-variable gravitational environment. Two

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

    NASA Image and Video Library

    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...

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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…

  1. 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…

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Exploring ESASky

    NASA Astrophysics Data System (ADS)

    De Marchi, Guido; ESASky Team

    2017-06-01

    ESASky is a science-driven discovery portal for all ESA space astronomy missions. It also includes missions from international partners such as Suzaku and Chandra. The first public release of ESASky features interfaces for sky exploration and for single and multiple target searches. Using the application requires no prior-knowledge of any of the missions involved and gives users world-wide simplified access to high-level science-ready data products from space-based Astronomy missions, plus a number of ESA-produced source catalogues, including the Gaia Data Release 1 catalogue. We highlight here the latest features to be developed, including one that allows the user to project onto the sky the footprints of the JWST instruments, at any chosen position and orientation. This tool has been developed to aid JWST astronomers when they are defining observing proposals. We aim to include other missions and instruments in the near future.

  8. 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.

  9. 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.

  10. PET: a proton/electron telescope for studies of magnetospheric, solar, and galactic particles

    SciTech Connect

    Cook, W.R.; Cummings, A.C.; Cummings, J.R.; Garrard, T.L.; Kecman, B.; Mewaldt, R.A.; Selesnick, R.S.; Stone, E.C. ); Baker, D.N.; Rosenvinge, T.T. von ); Callis, L.B. ); Blake, J.B.

    1993-05-01

    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 [approximately]1 to [approximately]30 MeV and H and He nuclei from [approximately]20 to [approximately]300 MeV/nuc, with isotope resolution of H and He extending from [approximately]20 to [approximately]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 O[sub 3] depletion. In addition, PET will complement studies of the elemental and isotopic composition of energetic heavy (Z > 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.

  11. Global ENA Imaging of the Jovian Magnetosphere: A Tool for Global Exploration of the Giant Accelerator of Energetic Particles and Their Interaction with the Torus Region and Moons (Invited)

    NASA Astrophysics Data System (ADS)

    Brandt, P. C.; Mitchell, D. G.; Mauk, B. H.; Paranicas, C.; Krupp, N.

    2010-12-01

    The Europa-Jupiter System Mision (EJSM) has required a synergistic approach within the JGO-JEO constellation to unravel fundamental and universal magnetospheric processes, by using powerful combinations of in-situ and global imaging measurement. The Japanese Space Agency is also considering a possible Jupiter Magnetospheric Orbiter (JMO), enabling triple point measurements and multi-point imaging to ensure simultaneous and continuous observations - a key requirement for revealing how the magnetosphere couples to the ionosphere as well as to the plasma sources. Energetic Neutral Atom (ENA) imaging is so far the only technique capable of obtaining global images of the magnetospheric energetic ion population in the ~3-300 keV range, which otherwise would have remained invisible. ENA cameras on Cassini and the terrestrial IMAGE mission have revealed global, explosive acceleration processes and their connection to the ionosphere, aurorae and radio emissions. Therefore, the technique is considered to be game-changing and one of the required measurement techniques in the payload definition for both JGO and JMO. In this presentation we discuss how ENA imaging can make use of the synergistic approach of EJSM to explore global acceleration, MI-coupling, relation to aurorae and radio emissions, transport, solar wind control, constrain torus neutral gas evolution and provide global context for moon-magnetosphere interactions in the Jovian magnetosphere. We use past measurements and a data-derived model to simulate ENA images through a realistic camera response function along the JGO orbit and explore the scientific value added by in-situ and imaging measurements from JMO. The presentation is concluded by summarizing the critical technical requirements of ENA cameras, such as energy and mass range, geometrical factor and background/foreground rejection that must be met in order to operate in the harsh Jovian environment while achieving the highest priority science objectives.

  12. 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.

  13. 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.

  14. 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.

  15. [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

  16. [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

  17. 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.

  18. 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.

  19. Space Exploration

    NASA Technical Reports Server (NTRS)

    Gallagher, Dennis

    2017-01-01

    New range Passage Tomb may be the first structure with known astronomical significance. It was built around 3,200 B.C. in Ireland. It's central passage allows light end-to-end for about 2 weeks around winter solstice. The Sun, Moon, Planets, and Stars held significance in early times due to the seasons, significance for food crops, and mythology. Citation: Corel Photography and Windows to the Universe The Greek may be among the first to pursue analytical interpretations of what they saw in the sky. In about 280 B.C. Aristarchus suggested Earth revolves around the Sun and estimated the distance between. Around 130 B.C. Hipparchus developed the first accurate star map. Today still seek to understand how the universe formed and how we came to be and are we alone. Understanding the causes and consequences of climate change using advanced space missions with major Earth science and applications research. center dotFire the public imagination and inspire students to pursue STEM fields. Train college and graduate students to create a U.S. technical workforce with employees that embody the values of competence, innovation, and service. center dotDrive the technical innovations that enable exploration and become the engine of National economic growth. center dotPartner domestically and internationally to leverage resources to extend the reach of research.

  20. 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.

  1. 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".

  2. Geospace exploration project: Arase (ERG)

    NASA Astrophysics Data System (ADS)

    Miyoshi, Y.; Kasaba, Y.; Shinohara, I.; Takashima, T.; Asamura, K.; Matsumoto, H.; Higashio, N.; Mitani, T.; Kasahara, S.; Yokota, S.; Wang, S.; Kazama, Y.; Kasahara, Y.; Yagitani, S.; Matsuoka, A.; Kojima, H.; Katoh, Y.; Shiokawa, K.; Seki, K.; Fujimoto, M.; Ono, T.; ERG project Group

    2017-06-01

    The ERG (Exploration of energization and Radiation in Geospace) is Japanese geospace exploration project. The project focuses on relativistic electron acceleration mechanism of the outer belt and dynamics of space storms in the context of the cross-energy coupling via wave-particle interactions. The project consists of the satellite observation team, the ground-based network observation team, and integrated-data analysis/simulation team. The satellite was launched on December 20 2016 and has been nicknamed, “Arase”. This paper describes overview of the project and future plan for observations.

  3. Shock driven multiphase flow with particle evaporation

    NASA Astrophysics Data System (ADS)

    Dahal, Jeevan; McFarland, Jacob

    2016-11-01

    The computational study of the shock driven instability of a multiphase system with particle evaporation is presented. The particle evaporation modifies the evolution of the interface due to the addition of the vapor phase to the gas. The effects can be quantitatively measured by studying various gas parameters like density, temperature, vorticity and particle properties like diameter and temperature. In addition, the size distribution of particles also modifies the development of instability as the larger size particles damp the evolution of interface in comparison to the smaller size particles. The simulation results are presented to study these effects using FLASH developed at the FLASH Center at the University of Chicago. The capabilities of FLASH for particle modeling were extended using the Particle in Cell (PIC) technique for coupling of mass, momentum, and energy between the particle and carrier gas. A seeded cylinder of gas with particles having either a single radius or a distribution of radii was studied. The enstrophy production and destruction mechanisms were explored to understand the reason for change in vorticity with particle size.

  4. 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.

  5. Particle physics -- Future directions

    SciTech Connect

    Chris Quigg

    2001-11-29

    Wonderful opportunities await particle physics over the next decade, with the coming of the Large Hadron Collider at CERN to explore the 1-TeV scale (extending efforts at LEP and the Tevatron to unravel the nature of electroweak symmetry breaking) and many initiatives to develop our understanding of the problem of identity: what makes a neutrino a neutrino and a top quark a top quark. Here I have in mind the work of the B factories and the Tevatron collider on CP violation and the weak interactions of the b quark; the wonderfully sensitive experiments at Brookhaven, CERN, Fermilab, and Frascati on CP violation and rare decays of kaons; the prospect of definitive accelerator experiments on neutrino oscillations and the nature of the neutrinos; and a host of new experiments on the sensitivity frontier. We might even learn to read experiment for clues about the dimensionality of spacetime. If we are inventive enough, we may be able to follow this rich menu with the physics opportunities offered by a linear collider and a (muon storage ring) neutrino factory. I expect a remarkable flowering of experimental particle physics, and of theoretical physics that engages with experiment. I describe some of the great questions before us and the challenges of providing the instruments that will be needed to define them more fully and eventually to answer them.

  6. Dynamics of Carroll particles

    NASA Astrophysics Data System (ADS)

    Bergshoeff, Eric; Gomis, Joaquim; Longhi, Giorgio

    2014-10-01

    We investigate particles whose dynamics are invariant under the Carroll group. Although a single, free such Carroll particle has no non-trivial dynamics (the Carroll particle does not move), we show that non-trivial dynamics exists for a set of interacting Carroll particles. Furthermore, we gauge the Carroll algebra and couple the Carroll particle to these gauge fields. It turns out that for such a coupled system, even a single Carroll particle can have non-trivial dynamics.

  7. 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.

  8. The Advanced Composition Explorer

    NASA Technical Reports Server (NTRS)

    Stone, E. C.; Burlaga, L. F.; Cummings, A. C.; Feldman, W. C.; Frain, W. E.; Geiss, J.; Gloeckler, G.; Gold, R. E.; Hovestadt, D.; Krimigis, S. M.

    1989-01-01

    The Advanced Composition Explorer (ACE) was recently selected as one of two new Explorer-class missions to be developed for launch during the mid-1990's. ACE will observe particles of solar, interplanetary, interstellar, and galactic origins, spanning the energy range from that of the solar wind (approx. 1 keV/nucleon) to galactic cosmic ray energies (several hundred MeV/nucleon). Definitive studies will be made of the abundance of nearly all isotopes from H to Zn (1 less than or = Z less than or = 30), with exploratory isotope studies extending to Zr (Z = 40). To accomplish this, the ACE payload includes six high-resolution spectrometers, each designed to provide the optimum charge, mass, or charge-state resolution in its particular energy range, and each having a geometry factor optimized for the expected flux levels, so as to provide a collecting power a factor of 10 to 1000 times greater than previous or planned experiments. The payload also includes several instruments of standard design that will monitor solar wind and magnetic field conditions and energetic H, He, and electron fluxes. The scientific objectives, instrumentation, spacecraft, and mission approach that were defined for ACE during the Phase-A study period are summarized.

  9. 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

  10. 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.

  11. 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.

  12. Design and Implementation of Embedded Computer Vision Systems Based on Particle Filters

    DTIC Science & Technology

    2010-01-01

    Keywords: Design space exploration Particle filters Reconfigurable platforms a b s t r a c t Particle filtering methods are gradually attaining significant...design space exploration of complete particle filtering systems that can be used across different applications. Exploration of the hardware/software co...even less attention devoted to efficient design space exploration through exploitation of reconfigurability and interactions among the various

  13. 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.

  14. 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

  15. 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.; hide

    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

  16. 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

  17. Outline of the Active Magnetospheric Particle Tracer Explorers (AMPTE) mission

    NASA Technical Reports Server (NTRS)

    Bryant, D. A.; Krimigis, S. M.; Haerendel, G.

    1985-01-01

    This paper is intended as an introduction to a series of papers describing the three satellites of the AMPTE mission and their instrumentation. The aims and scientific context of the program are given together with a comparison of the general characteristics of the three spacecraft and their orbits. There is a brief resume of the studies performed so far, and a statement of future plans, together with a calendar of completed and planned experiments and measurements.

  18. Lagrangian coherent structures and inertial particle dynamics.

    PubMed

    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.

  19. 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.

  20. Particle capture device

    DOEpatents

    Jayne, John T.; Worsnop, Douglas R.

    2016-02-23

    In example embodiments, particle collection efficiency in aerosol analyzers and other particle measuring instruments is improved by a particle capture device that employs multiple collisions to decrease momentum of particles until the particles are collected (e.g., vaporized or come to rest). The particle collection device includes an aperture through which a focused particle beam enters. A collection enclosure is coupled to the aperture and has one or more internal surfaces against which particles of the focused beam collide. One or more features are employed in the collection enclosure to promote particles to collide multiple times within the enclosure, and thereby be vaporized or come to rest, rather than escape through the aperture.

  1. Laser particle sorter

    DOEpatents

    Martin, J.C.; Buican, T.N.

    1987-11-30

    Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

  2. Laser particle sorter

    DOEpatents

    Martin, John C.; Buican, Tudor N.

    1989-01-01

    Method and apparatus for sorting particles, such as biological particles. A first laser defines an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam interrogates the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam intersects the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis.

  3. Snap-in of particles at curved liquid interfaces

    NASA Astrophysics Data System (ADS)

    Li, Chao; Moradiafrapoli, Momene; Marston, Jeremy

    2016-11-01

    The contact of particles with liquid interfaces constitutes the first stage in the formation of a particle-laden interface, the so-called "snap-in effect". Here, we report on an experimental study using high-speed video to directly visualize the snap-in process and the approach to the equilibrium state of a particle at a curved liquid interface (i.e. droplet surface). We image the evolution of the contact line, which is found to follow a power-law scaling in time, and the dynamic contact angle during the snap-in. Both hydrophilic and hydrophobic particles are explored and we match the lift-off stage of the particles with a simple force balance. We also explore some multi-particle experiments, eluding to the dynamics of particle-laden interface formation.

  4. Astrobiology and Venus Exploration

    NASA Astrophysics Data System (ADS)

    Grinspoon, D. H.; Bullock, M. A.

    2005-12-01

    Venus has not traditionally been considered a promising target for Astrobiological exploration. We propose that Venus should be central to such an exploration program for several reasons. 1) Putting Earth life in context: Venus is the only other Earth-sized terrestrial planet that we know of, and certainly the only one we will have the opportunity to explore in the foreseeable future. Many geological and meteorological processes otherwise active only on Earth at present are currently active on Venus. For example, active volcanism is most likely responsible for maintaining the global cloud cover (Bullock and Grinspoon, 2001). Understanding the divergence of Earth and Venus is central to understanding the limits of habitability in the inner regions of habitable zones around solar-type stars. Thus Venus presents us with a unique opportunity for putting the bulk properties, evolution and ongoing geochemical processes of Earth in a wider context. 2) The possibility of extant life: Venus almost surely once had warm oceans. The evaporation of these oceans, and subsequent escape of hydrogen, most likely resulted in an oxygenated atmosphere. The duration of this phase is poorly understood, but during this time the terrestrial planets were not isolated. Rather, due to frequent impact transport, they represented a continuous environment for early microbial 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

  5. Sounding rockets explore the ionosphere

    SciTech Connect

    Mendillo, M. )

    1990-08-01

    It is suggested that small, expendable, solid-fuel rockets used to explore ionospheric plasma can offer insight into all the processes and complexities common to space plasma. NASA's sounding rocket program for ionospheric research focuses on the flight of instruments to measure parameters governing the natural state of the ionosphere. Parameters include input functions, such as photons, particles, and composition of the neutral atmosphere; resultant structures, such as electron and ion densities, temperatures and drifts; and emerging signals such as photons and electric and magnetic fields. Systematic study of the aurora is also conducted by these rockets, allowing sampling at relatively high spatial and temporal rates as well as investigation of parameters, such as energetic particle fluxes, not accessible to ground based systems. Recent active experiments in the ionosphere are discussed, and future sounding rocket missions are cited.

  6. Particle Tracks in Aerogel

    NASA Image and Video Library

    2005-11-03

    In an experiment using a special air gun, particles are shot into aerogel at high velocities. Closeup of particles leaving a carrot-shaped trail in the aerogel are shown here. Aerogel was used on NASA Stardust spacecraft.

  7. Charged Particle Flux Sensor

    NASA Technical Reports Server (NTRS)

    Gregory, D. A.; Stocks, C. D.

    1983-01-01

    Improved version of Faraday cup increases accuracy of measurements of flux density of charged particles incident along axis through collection aperture. Geometry of cone-and-sensing cup combination assures most particles are trapped.

  8. Composite powder particles

    NASA Technical Reports Server (NTRS)

    Parker, Donald S. (Inventor); MacDowell, Louis G. (Inventor)

    2009-01-01

    A liquid coating composition including a coating vehicle and composite powder particles disposed within the coating vehicle. Each composite powder particle may include a magnesium component, a zinc component, and an indium component.

  9. Particle exposures and infections

    EPA Science Inventory

    Particle exposures increase the risk for human infections. Particles can deposit in the nose, pharynx, larynx, trachea, bronchi, and distal lung and, accordingly, the respiratory tract is the system most frequently infected after such exposure; however, meningitis also occurs. Ci...

  10. Solar Neutral Particles

    NASA Image and Video Library

    This animation shows a neutral solar particle's path leaving the sun, following the magnetic field lines out to the heliosheath. The solar particle hits a hydrogen atom, stealing its electron, and ...

  11. Particle physics: Axions exposed

    NASA Astrophysics Data System (ADS)

    Lombardo, Maria Paola

    2016-11-01

    Physicists are hunting for a particle called the axion that could solve two major puzzles in fundamental physics. An ambitious study calculates the expected mass of this particle, which might reshape the experimental searches. See Letter p.69

  12. Particle exposures and infections

    EPA Science Inventory

    Particle exposures increase the risk for human infections. Particles can deposit in the nose, pharynx, larynx, trachea, bronchi, and distal lung and, accordingly, the respiratory tract is the system most frequently infected after such exposure; however, meningitis also occurs. Ci...

  13. A multimission three-axis stabilized spacecraft flight dynamics ground support system

    NASA Technical Reports Server (NTRS)

    Langston, J.; Krack, K.; Reupke, W.

    1993-01-01

    The Multimission Three-Axis Stabilized Spacecraft (MTASS) Flight Dynamics Support System (FDSS) has been developed in an effort to minimize the costs of ground support systems. Unlike single-purpose ground support systems, which attempt to reduce costs by reusing software specifically developed for previous missions, the multimission support system is an intermediate step in the progression to a fully generalized mission support system in which numerous missions may be served by one general system. The benefits of multimission attitude ground support systems extend not only to the software design and coding process, but to the entire system environment, from specification through testing, simulation, operations, and maintenance. This paper reports the application of an MTASS FDSS to multiple scientific satellite missions. The satellites are the Upper Atmosphere Research Satellite (UARS), the Extreme Ultraviolet Explorer (EUVE), and the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX). Both UARS and EUVE use the multimission modular spacecraft (MMS) concept. SAMPEX is part of the Small Explorer (SMEX) series and uses a much simpler set of attitude sensors. This paper centers on algorithm and design concepts for a multimission system and discusses flight experience from UARS.

  14. A multimission three-axis stabilized spacecraft flight dynamics ground support system

    NASA Astrophysics Data System (ADS)

    Langston, J.; Krack, K.; Reupke, W.

    1993-02-01

    The Multimission Three-Axis Stabilized Spacecraft (MTASS) Flight Dynamics Support System (FDSS) has been developed in an effort to minimize the costs of ground support systems. Unlike single-purpose ground support systems, which attempt to reduce costs by reusing software specifically developed for previous missions, the multimission support system is an intermediate step in the progression to a fully generalized mission support system in which numerous missions may be served by one general system. The benefits of multimission attitude ground support systems extend not only to the software design and coding process, but to the entire system environment, from specification through testing, simulation, operations, and maintenance. This paper reports the application of an MTASS FDSS to multiple scientific satellite missions. The satellites are the Upper Atmosphere Research Satellite (UARS), the Extreme Ultraviolet Explorer (EUVE), and the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX). Both UARS and EUVE use the multimission modular spacecraft (MMS) concept. SAMPEX is part of the Small Explorer (SMEX) series and uses a much simpler set of attitude sensors. This paper centers on algorithm and design concepts for a multimission system and discusses flight experience from UARS.

  15. Axionlike particle assisted strongly interacting massive particle

    NASA Astrophysics Data System (ADS)

    Kamada, Ayuki; Kim, Hyungjin; Sekiguchi, Toyokazu

    2017-07-01

    We propose a new realization of strongly interacting massive particles (SIMPs) as self-interacting dark matter, where SIMPs couple to the standard model (SM) sector through an axionlike particle. Our model overcomes major obstacles accompanying the original SIMP model, such as a missing mechanism of kinetically equilibrating SIMPs with the SM plasma as well as marginal perturbativity of the chiral Lagrangian density. Remarkably, the parameter region realizing σself/mDM≃0.1 - 1 cm2/g is within the reach of future beam dump experiments such as the Search for Hidden Particles experiment.

  16. Solar flare particle radiation

    NASA Technical Reports Server (NTRS)

    Lanzerotti, L. J.

    1972-01-01

    The characteristics of the solar particles accelerated by solar flares and subsequently observed near the orbit of the earth are studied. Considered are solar particle intensity-time profiles, the composition and spectra of solar flare events, and the propagation of solar particles in interplanetary space. The effects of solar particles at the earth, riometer observations of polar cap cosmic noise absorption events, and the production of solar cell damage at synchronous altitudes by solar protons are also discussed.

  17. Classical confined particles

    NASA Technical Reports Server (NTRS)

    Horzela, Andrzej; Kapuscik, Edward

    1993-01-01

    An alternative picture of classical many body mechanics is proposed. In this picture particles possess individual kinematics but are deprived from individual dynamics. Dynamics exists only for the many particle system as a whole. The theory is complete and allows to determine the trajectories of each particle. It is proposed to use our picture as a classical prototype for a realistic theory of confined particles.

  18. 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.

  19. Anatomy of Particle Diffusion

    ERIC Educational Resources Information Center

    Bringuier, E.

    2009-01-01

    The paper analyses particle diffusion from a thermodynamic standpoint. The main goal of the paper is to highlight the conceptual connection between particle diffusion, which belongs to non-equilibrium statistical physics, and mechanics, which deals with particle motion, at the level of third-year university courses. We start out from the fact…

  20. When is a Particle?

    ERIC Educational Resources Information Center

    Drell, Sidney D.

    1978-01-01

    Gives a new definition for the concept of the elementary particle in nuclear physics. Explains why the existance of the quark as an elementary particle could be an accepted fact even though it lacks what traditionally identifies a particle. Compares this with the development which took place during the discovery of the neutrino in the early…

  1. Particle charge spectrometer

    NASA Technical Reports Server (NTRS)

    Fuerstenau, Stephen D. (Inventor)

    2004-01-01

    An airflow through a tube is used to guide a charged particle through the tube. A detector may be used to detect charge passing through the tube on the particle. The movement of the particle through the tube may be used to both detect its charge and size.

  2. Anatomy of Particle Diffusion

    ERIC Educational Resources Information Center

    Bringuier, E.

    2009-01-01

    The paper analyses particle diffusion from a thermodynamic standpoint. The main goal of the paper is to highlight the conceptual connection between particle diffusion, which belongs to non-equilibrium statistical physics, and mechanics, which deals with particle motion, at the level of third-year university courses. We start out from the fact…

  3. When is a Particle?

    ERIC Educational Resources Information Center

    Drell, Sidney D.

    1978-01-01

    Gives a new definition for the concept of the elementary particle in nuclear physics. Explains why the existance of the quark as an elementary particle could be an accepted fact even though it lacks what traditionally identifies a particle. Compares this with the development which took place during the discovery of the neutrino in the early…

  4. High energy particle astronomy.

    NASA Technical Reports Server (NTRS)

    Buffington, A.; Muller, R. A.; Smith, L. H.; Smoot, G. F.

    1972-01-01

    Discussion of techniques currently used in high energy particle astronomy for measuring charged and neutral cosmic rays and their isotope and momentum distribution. Derived from methods developed for accelerator experiments in particle physics, these techniques help perform important particle astronomy experiments pertaining to nuclear cosmic ray and gamma ray research, electron and position probes, and antimatter searches.

  5. High energy particle astronomy.

    NASA Technical Reports Server (NTRS)

    Buffington, A.; Muller, R. A.; Smith, L. H.; Smoot, G. F.

    1972-01-01

    Discussion of techniques currently used in high energy particle astronomy for measuring charged and neutral cosmic rays and their isotope and momentum distribution. Derived from methods developed for accelerator experiments in particle physics, these techniques help perform important particle astronomy experiments pertaining to nuclear cosmic ray and gamma ray research, electron and position probes, and antimatter searches.

  6. Selectively-informed particle swarm optimization

    PubMed Central

    Gao, Yang; Du, Wenbo; Yan, Gang

    2015-01-01

    Particle swarm optimization (PSO) is a nature-inspired algorithm that has shown outstanding performance in solving many realistic problems. In the original PSO and most of its variants all particles are treated equally, overlooking the impact of structural heterogeneity on individual behavior. Here we employ complex networks to represent the population structure of swarms and propose a selectively-informed PSO (SIPSO), in which the particles choose different learning strategies based on their connections: a densely-connected hub particle gets full information from all of its neighbors while a non-hub particle with few connections can only follow a single yet best-performed neighbor. Extensive numerical experiments on widely-used benchmark functions show that our SIPSO algorithm remarkably outperforms the PSO and its existing variants in success rate, solution quality, and convergence speed. We also explore the evolution process from a microscopic point of view, leading to the discovery of different roles that the particles play in optimization. The hub particles guide the optimization process towards correct directions while the non-hub particles maintain the necessary population diversity, resulting in the optimum overall performance of SIPSO. These findings deepen our understanding of swarm intelligence and may shed light on the underlying mechanism of information exchange in natural swarm and flocking behaviors. PMID:25787315

  7. Selectively-informed particle swarm optimization

    NASA Astrophysics Data System (ADS)

    Gao, Yang; Du, Wenbo; Yan, Gang

    2015-03-01

    Particle swarm optimization (PSO) is a nature-inspired algorithm that has shown outstanding performance in solving many realistic problems. In the original PSO and most of its variants all particles are treated equally, overlooking the impact of structural heterogeneity on individual behavior. Here we employ complex networks to represent the population structure of swarms and propose a selectively-informed PSO (SIPSO), in which the particles choose different learning strategies based on their connections: a densely-connected hub particle gets full information from all of its neighbors while a non-hub particle with few connections can only follow a single yet best-performed neighbor. Extensive numerical experiments on widely-used benchmark functions show that our SIPSO algorithm remarkably outperforms the PSO and its existing variants in success rate, solution quality, and convergence speed. We also explore the evolution process from a microscopic point of view, leading to the discovery of different roles that the particles play in optimization. The hub particles guide the optimization process towards correct directions while the non-hub particles maintain the necessary population diversity, resulting in the optimum overall performance of SIPSO. These findings deepen our understanding of swarm intelligence and may shed light on the underlying mechanism of information exchange in natural swarm and flocking behaviors.

  8. Cutting Silica Aerogel for Particle Extraction

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Brownlee, D. E.; Glesias, R.; Grigoropoulos, C. P.; Weschler, M.

    2005-01-01

    The detailed laboratory analyses of extraterrestrial particles have revolutionized our knowledge of planetary bodies in the last three decades. This knowledge of chemical composition, morphology, mineralogy, and isotopics of particles cannot be provided by remote sensing. In order to acquire these detail information in the laboratories, the samples need be intact, unmelted. Such intact capture of hypervelocity particles has been developed in 1996. Subsequently silica aerogel was introduced as the preferred medium for intact capturing of hypervelocity particles and later showed it to be particularly suitable for the space environment. STARDUST, the 4th NASA Discovery mission to capture samples from 81P/Wild 2 and contemporary interstellar dust, is the culmination of these new technologies. In early laboratory experiments of launching hypervelocity projectiles into aerogel, there was the need to cut aerogel to isolate or extract captured particles/tracks. This is especially challenging for space captures, since there will be many particles/tracks of wide ranging scales closely located, even collocated. It is critical to isolate and extract one particle without compromising its neighbors since the full significance of a particle is not known until it is extracted and analyzed. To date, three basic techniques have been explored: mechanical cutting, lasers cutting and ion beam milling. We report the current findings.

  9. Spatially resolved chemical imaging of individual atmospheric particles using nanoscale imaging mass spectrometry: insight into particle origin and chemistry

    DOE PAGES

    Ghosal, Sutapa; Weber, Peter K.; Laskin, Alexander

    2014-01-14

    Knowledge of the spatially resolved composition of atmospheric particles is essential for differentiating between their surface versus bulk chemistry and understanding particle reactivity and the potential environmental impact. Here, we demonstrate the application of nanometer-scale secondary ion mass spectrometry (CAMECA NanoSIMS 50 ion probe) for 3D chemical imaging of individual atmospheric particles without any sample pre-treatment, such as sectioning of particles. Use of NanoSIMS depth profile analysis enables elemental mapping of particles with nanometer spatial resolution over a broad range of particle sizes. We have used this technique to probe the spatially resolved composition of ambient particles collected during amore » field campaign in Mexico City. Particles collected during this campaign have been extensively characterized in the past using other particle analysis techniques and hence offer a unique opportunity for exploring the utility of depth-resolved chemical imaging in ambient particle research. The particles that we examined in our study include those collected during a pollution episode related to urban waste incineration as well as background particles from the same location before the episode. Particles from the pollution episode show substantial intra-particle compositional variability typical of particles resulting from multiple emission sources. In contrast, the background particles have relatively homogeneous compositions with enhanced presence of nitrogen, oxygen, and chlorine at the particle surface. We also observed the surface enhancement of nitrogen and oxygen species is consistent with the presence of surface nitrates resulting from gas–particle heterogeneous interactions and is indicative of atmospheric ageing of the particles. The results presented here illustrate 3D characterization of ambient particles for insight into their chemical history.« less

  10. Spatially resolved chemical imaging of individual atmospheric particles using nanoscale imaging mass spectrometry: Insighs into particle origin and chemistry

    SciTech Connect

    Ghosal, Sutapa; Weber, Peter K.; Laskin, Alexander

    2014-04-21

    Knowledge of the spatially-resolved composition of atmospheric particles is essential for differentiating between their surface versus bulk chemistry, understanding particle reactivity and the potential environmental impact. We demonstrate the application of nanometer-scale secondary ion mass spectrometry (Cameca NanoSIMS 50 ion probe) for 3D chemical imaging of individual atmospheric particles without any sample pre-treatment, such as the sectioning of particles. Use of NanoSIMS depth profile analysis enables elemental mapping of particles with nanometer spatial resolution over a broad of range of particle sizes. We have used this technique to probe spatially resolved composition of ambient particles collected during a field campaign in Mexico City. Particles collected during this campaign have been extensively characterized in the past using other particle analysis techniques and hence offer a unique opportunity for exploring the utility of depth resolved chemical imaging in ambient particle research. 1 Particles examined in this study include those collected during a pollution episode related to urban waste incineration as well as background particles from the same location prior to the episode. Particles from the pollution episode show substantial intra-particle compositional variability typical of particles resulting from multiple emission sources. In contrast, the background particles have relatively homogeneous compositions with enhanced presence of nitrogen, oxygen and chlorine at the particle surface. The observed surface enhancement of nitrogen and oxygen species is consistent with the presence of surface nitrates resulting from gas-particle heterogeneous interactions and is indicative of atmospheric ageing of the particles. The results presented here illustrate 3D characterization of ambient particles for insights into their chemical history.

  11. Spatially resolved chemical imaging of individual atmospheric particles using nanoscale imaging mass spectrometry: insight into particle origin and chemistry

    SciTech Connect

    Ghosal, Sutapa; Weber, Peter K.; Laskin, Alexander

    2014-01-14

    Knowledge of the spatially resolved composition of atmospheric particles is essential for differentiating between their surface versus bulk chemistry and understanding particle reactivity and the potential environmental impact. Here, we demonstrate the application of nanometer-scale secondary ion mass spectrometry (CAMECA NanoSIMS 50 ion probe) for 3D chemical imaging of individual atmospheric particles without any sample pre-treatment, such as sectioning of particles. Use of NanoSIMS depth profile analysis enables elemental mapping of particles with nanometer spatial resolution over a broad range of particle sizes. We have used this technique to probe the spatially resolved composition of ambient particles collected during a field campaign in Mexico City. Particles collected during this campaign have been extensively characterized in the past using other particle analysis techniques and hence offer a unique opportunity for exploring the utility of depth-resolved chemical imaging in ambient particle research. The particles that we examined in our study include those collected during a pollution episode related to urban waste incineration as well as background particles from the same location before the episode. Particles from the pollution episode show substantial intra-particle compositional variability typical of particles resulting from multiple emission sources. In contrast, the background particles have relatively homogeneous compositions with enhanced presence of nitrogen, oxygen, and chlorine at the particle surface. We also observed the surface enhancement of nitrogen and oxygen species is consistent with the presence of surface nitrates resulting from gas–particle heterogeneous interactions and is indicative of atmospheric ageing of the particles. The results presented here illustrate 3D characterization of ambient particles for insight into their chemical history.

  12. Spatially resolved chemical imaging of individual atmospheric particles using nanoscale imaging mass spectrometry: Insights into particle origin and chemistry

    NASA Astrophysics Data System (ADS)

    Ghosal, S.; Weber, P. K.; Laskin, A.

    2014-12-01

    Knowledge of the spatially-resolved composition of atmospheric particles is essential for differentiating between their surface versus bulk chemistry, understanding particle reactivity and the potential environmental impact. We demonstrate the application of nanometer-scale secondary ion mass spectrometry (Cameca NanoSIMS 50 ion probe) for 3D chemical imaging of individual atmospheric particles without any sample pre-treatment, such as the sectioning of particles. Use of NanoSIMS depth profile analysis enables elemental mapping of particles with nanometer spatial resolution over a broad of range of particle sizes. We have used this technique to probe spatially resolved composition of ambient particles collected during a field campaign in Mexico City. Particles collected during this campaign have been extensively characterized in the past using other particle analysis techniques and hence offer a unique opportunity for exploring the utility of depth resolved chemical imaging in ambient particle research. Particles examined in this study include those collected during a pollution episode related to urban waste incineration as well as background particles from the same location prior to the episode. Particles from the pollution episode show substantial intra-particle compositional variability typical of particles resulting from multiple emission sources. In contrast, the background particles have relatively homogeneous compositions with enhanced presence of nitrogen, oxygen and chlorine at the particle surface. The observed surface enhancement of nitrogen and oxygen species is consistent with the presence of surface nitrates resulting from gas-particle heterogeneous interactions and is indicative of atmospheric ageing of the particles. The results presented here illustrate 3D characterization of ambient particles for insights into their chemical history.

  13. Radiation Belt Electron Enhancements: History and Prospects for RBSP

    NASA Astrophysics Data System (ADS)

    Baker, Daniel N.; Kanekal, Shrikanth; Elkington, Scot

    2012-07-01

    Energetic electron data from low-altitude Earth-orbiting spacecraft show both a long historical record of the Van Allen radiation belts and the specific effects of powerful storms such as the 2003 Halloween storms. The fluxes of 2-6 MeV electrons measured by the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) from July 1992 to the current time are presented in this talk. Data demonstrate intense electron acceleration events (associated with high-speed solar wind), for example, in 1993-95 for 3SAMPEX electron data for 2003 and throughout 2004 and 2005 show the shifted position of the outer Van Allen zone and the filling of the slot region (L<3). A persistent new belt of electrons was produced in the wake of the Halloween storms and this was clearly seen for L<2 for several years. We note that recent SAMPEX data demonstrate that in 2008 and 2009, the radiation belts virtually disappeared due to very weak solar wind driving conditions associated with the recent profound solar activity minimum period. Building on this historical record, we describe the expected results from the Relativistic Electron-Proton Telescope (REPT) instrument that will be launched onboard the Radiation Belt Storm Probes mission. Key areas of likely scientific progress using REPT will be addressed.

  14. 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)

  15. 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)

  16. Progress in the Analysis of Complex Atmospheric Particles.

    PubMed

    Laskin, Alexander; Gilles, Mary K; Knopf, Daniel A; Wang, Bingbing; China, Swarup

    2016-06-12

    This article presents an overview of recent advances in field and laboratory studies of atmospheric particles formed in processes of environmental air-surface interactions. The overarching goal of these studies is to advance predictive understanding of atmospheric particle composition, particle chemistry during aging, and their environmental impacts. The diversity between chemical constituents and lateral heterogeneity within individual particles adds to the chemical complexity of particles and their surfaces. Once emitted, particles undergo transformation via atmospheric aging processes that further modify their complex composition. We highlight a range of modern analytical approaches that enable multimodal chemical characterization of particles with both molecular and lateral specificity. When combined, these approaches provide a comprehensive arsenal of tools for understanding the nature of particles at air-surface interactions and their reactivity and transformations with atmospheric aging. We discuss applications of these novel approaches in recent studies and highlight additional research areas to explore the environmental effects of air-surface interactions.

  17. Progress in the Analysis of Complex Atmospheric Particles

    SciTech Connect

    Laskin, Alexander; Gilles, Mary K.; Knopf, Daniel A.; Wang, Bingbing; China, Swarup

    2016-06-16

    This manuscript presents an overview on recent advances in field and laboratory studies of atmospheric particles formed in processes of environmental air-surfaces interactions. The overarching goal of these studies is to advance predictive understanding of atmospheric particle composition, particle chemistry during aging, and their environmental impacts. The diversity between chemical constituents and lateral heterogeneity within individual particles adds to the chemical complexity of particles and their surfaces. Once emitted, particles undergo transformation via atmospheric aging processes that further modify their complex composition. We highlight a range of modern analytical approaches that enable multi-modal chemical characterization of particles with both molecular and lateral specificity. When combined, they provide a comprehensive arsenal of tools for understanding the nature of particles at air-surface interactions and their reactivity and transformations with atmospheric aging. We discuss applications of these novel approaches in recent studies and highlight additional research areas to explore environmental effects of air-surface interactions.

  18. Progress in the analysis of complex atmospheric particles

    SciTech Connect

    Laskin, Alexander; Gilles, Mary K.; Knopf, Daniel A.; Wang, Bingbing; China, Swarup

    2016-06-01

    This study presents an overview of recent advances in field and laboratory studies of atmospheric particles formed in processes of environmental air-surface interactions. The overarching goal of these studies is to advance predictive understanding of atmospheric particle composition, particle chemistry during aging, and their environmental impacts. The diversity between chemical constituents and lateral heterogeneity within individual particles adds to the chemical complexity of particles and their surfaces. Once emitted, particles undergo transformation via atmospheric aging processes that further modify their complex composition. We highlight a range of modern analytical approaches that enable multimodal chemical characterization of particles with both molecular and lateral specificity. When combined, these approaches provide a comprehensive arsenal of tools for understanding the nature of particles at air-surface interactions and their reactivity and transformations with atmospheric aging. We discuss applications of these novel approaches in recent studies and highlight additional research areas to explore the environmental effects of air-surface interactions.

  19. Progress in the Analysis of Complex Atmospheric Particles

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Gilles, Mary K.; Knopf, Daniel A.; Wang, Bingbing; China, Swarup

    2016-06-01

    This article presents an overview of recent advances in field and laboratory studies of atmospheric particles formed in processes of environmental air-surface interactions. The overarching goal of these studies is to advance predictive understanding of atmospheric particle composition, particle chemistry during aging, and their environmental impacts. The diversity between chemical constituents and lateral heterogeneity within individual particles adds to the chemical complexity of particles and their surfaces. Once emitted, particles undergo transformation via atmospheric aging processes that further modify their complex composition. We highlight a range of modern analytical approaches that enable multimodal chemical characterization of particles with both molecular and lateral specificity. When combined, these approaches provide a comprehensive arsenal of tools for understanding the nature of particles at air-surface interactions and their reactivity and transformations with atmospheric aging. We discuss applications of these novel approaches in recent studies and highlight additional research areas to explore the environmental effects of air-surface interactions.

  20. Progress in the analysis of complex atmospheric particles

    SciTech Connect

    Laskin, Alexander; Gilles, Mary K.; Knopf, Daniel A.; Wang, Bingbing; China, Swarup

    2016-06-01

    This study presents an overview of recent advances in field and laboratory studies of atmospheric particles formed in processes of environmental air-surface interactions. The overarching goal of these studies is to advance predictive understanding of atmospheric particle composition, particle chemistry during aging, and their environmental impacts. The diversity between chemical constituents and lateral heterogeneity within individual particles adds to the chemical complexity of particles and their surfaces. Once emitted, particles undergo transformation via atmospheric aging processes that further modify their complex composition. We highlight a range of modern analytical approaches that enable multimodal chemical characterization of particles with both molecular and lateral specificity. When combined, these approaches provide a comprehensive arsenal of tools for understanding the nature of particles at air-surface interactions and their reactivity and transformations with atmospheric aging. We discuss applications of these novel approaches in recent studies and highlight additional research areas to explore the environmental effects of air-surface interactions.

  1. Primordial Particles; Collisions of Inelastic Particles

    NASA Astrophysics Data System (ADS)

    Sagi, George

    2011-03-01

    Three-dimensional matter is not defined by Euclidian or Cartesian geometries. Newton's and Einstein's laws are related to the motions of elastic masses. The study of collisions of inelastic particles opens up new vistas in physics. The present article reveals how such particles create clusters composed of various numbers of particles. The Probability of each formation, duplets, triplets, etc. can be calculated. The particles are held together by a binding force, and depending upon the angles of collisions they may also rotate around their center of geometry. Because of these unique properties such inelastic particles are referred to as primordial particles, Pp. When a given density of Pp per cubic space is given, then random collisions create a field. The calculation of the properties of such primordial field is very complex and beyond the present study. However, the angles of collisions are infinite in principle, but the probabilities of various cluster sizes are quantum dependent. Consequently, field calculations will require new complex mathematical methods to be discovered yet.

  2. Particle Accelerators in China

    NASA Astrophysics Data System (ADS)

    Zhang, Chuang; Fang, Shouxian

    As the special machines that can accelerate charged particle beams to high energy by using electromagnetic fields, particle accelerators have been widely applied in scientific research and various areas of society. The development of particle accelerators in China started in the early 1950s. After a brief review of the history of accelerators, this article describes in the following sections: particle colliders, heavy-ion accelerators, high-intensity proton accelerators, accelerator-based light sources, pulsed power accelerators, small scale accelerators, accelerators for applications, accelerator technology development and advanced accelerator concepts. The prospects of particle accelerators in China are also presented.

  3. An Overview of Particle Sampling Bias

    NASA Technical Reports Server (NTRS)

    Meyers, James F.; Edwards, Robert V.

    1984-01-01

    The complex relation between particle arrival statistics and the interarrival statistics is explored. It is known that the mean interarrival time given an initial velocity is generally not the inverse of the mean rate corresponding to that velocity. Necessary conditions for the measurement of the conditional rate are given.

  4. Visions: The coming revolutions in particle physics

    SciTech Connect

    Chris Quigg

    2002-04-11

    Wonderful opportunities await particle physics over the next decade, with the coming of the Large Hadron Collider to explore the 1-TeV scale (extending efforts at LEP and the Tevatron to unravel the nature of electroweak symmetry breaking) and many initiatives to develop the understanding of the problem of identity and the dimensionality of spacetime.

  5. Exploration Technology Development & Demonstration

    NASA Image and Video Library

    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....

  6. Fluidization of spherocylindrical particles

    NASA Astrophysics Data System (ADS)

    Mahajan, Vinay V.; Nijssen, Tim M. J.; Fitzgerald, Barry W.; Hofman, Jeroen; Kuipers, Hans; Padding, Johan T.

    2017-06-01

    Multiphase (gas-solid) flows are encountered in numerous industrial applications such as pharmaceutical, food, agricultural processing and energy generation. A coupled computational fluid dynamics (CFD) and discrete element method (DEM) approach is a popular way to study such flows at a particle scale. However, most of these studies deal with spherical particles while in reality, the particles are rarely spherical. The particle shape can have significant effect on hydrodynamics in a fluidized bed. Moreover, most studies in literature use inaccurate drag laws because accurate laws are not readily available. The drag force acting on a non-spherical particle can vary considerably with particle shape, orientation with the flow, Reynolds number and packing fraction. In this work, the CFD-DEM approach is extended to model a laboratory scale fluidized bed of spherocylinder (rod-like) particles. These rod-like particles can be classified as Geldart D particles and have an aspect ratio of 4. Experiments are performed to study the particle flow behavior in a quasi-2D fluidized bed. Numerically obtained results for pressure drop and bed height are compared with experiments. The capability of CFD-DEM approach to efficiently describe the global bed dynamics for fluidized bed of rod-like particles is demonstrated.

  7. Adhesive particle shielding

    DOEpatents

    Klebanoff, Leonard Elliott; Rader, Daniel John; Walton, Christopher; Folta, James

    2009-01-06

    An efficient device for capturing fast moving particles has an adhesive particle shield that includes (i) a mounting panel and (ii) a film that is attached to the mounting panel wherein the outer surface of the film has an adhesive coating disposed thereon to capture particles contacting the outer surface. The shield can be employed to maintain a substantially particle free environment such as in photolithographic systems having critical surfaces, such as wafers, masks, and optics and in the tools used to make these components, that are sensitive to particle contamination. The shield can be portable to be positioned in hard-to-reach areas of a photolithography machine. The adhesive particle shield can incorporate cooling means to attract particles via the thermophoresis effect.

  8. Laser cooling and trapping of atoms and particles

    NASA Astrophysics Data System (ADS)

    Chu, Steven

    1992-01-01

    The program was to explore the use of light to manipulate atoms and other particles. Particularly, the cooling and trapping of atoms, the manipulation of biological molecules, and the creations of new devices based on these techniques.

  9. 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

  10. Comparison of Solar Energetic Particle Flux Mapping Models

    NASA Astrophysics Data System (ADS)

    Young, S. L.; Roth, C. M.; Brodowski, C. M.; Kress, B. T.; Johnston, W. R.; Huston, S. L.; McCollough, J. P., II; Wilson, G.; Selesnick, R.

    2015-12-01

    Previous work using the Tsyganenko-Sitnov 2005 (TS05) magnetic field model combined withthe Dartmouth-CISM (DC) cutoff code to map GOES-7 SEM observations to CRRES locationshas demonstrated that, for reasonably static magnetospheric conditions, solar energetic particleobservations at GOES-7 can be mapped relatively accurately to locations inside of geosynchronouswhere L > 4.5. Also a good correlation with observations continues to approximately L = 3.5. Aprevious comparison of the TS05-DC combination with two other cutoff models found it to be themost accurate of the set when compared to SAMPEX observations in a LEO orbit. However, theTS05-DC combination requires significant computational resources compared to other models soit is important to quantify the difference in accuracy for operational purposes. In this study wecharacterize the Smart and Shea (SS) cutoff code and the Selesnick-Neal-Ogliore (SNO) model andcompare them to the TS05-DC cutoff model.

  11. Diffraction of entangled particles by light gratings

    SciTech Connect

    Sancho, Pedro

    2015-04-15

    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. - Highlights: • Kapitza–Dirac diffraction of entangled particles shows multiparticle interference. • There is a discontinuity in the set of joint detection patterns of entangled states. • We find a complementary behavior between overlapping and Schmidt’s number. • Symmetric entanglement can cancel the exchange effects.

  12. Fuzzy Logic Particle Tracking

    NASA Technical Reports Server (NTRS)

    2005-01-01

    A new all-electronic Particle Image Velocimetry technique that can efficiently map high speed gas flows has been developed in-house at the NASA Lewis Research Center. Particle Image Velocimetry is an optical technique for measuring the instantaneous two component velocity field across a planar region of a seeded flow field. A pulsed laser light sheet is used to illuminate the seed particles entrained in the flow field at two instances in time. One or more charged coupled device (CCD) cameras can be used to record the instantaneous positions of particles. Using the time between light sheet pulses and determining either the individual particle displacements or the average displacement of particles over a small subregion of the recorded image enables the calculation of the fluid velocity. Fuzzy logic minimizes the required operator intervention in identifying particles and computing velocity. Using two cameras that have the same view of the illumination plane yields two single exposure image frames. Two competing techniques that yield unambiguous velocity vector direction information have been widely used for reducing the single-exposure, multiple image frame data: (1) cross-correlation and (2) particle tracking. Correlation techniques yield averaged velocity estimates over subregions of the flow, whereas particle tracking techniques give individual particle velocity estimates. For the correlation technique, the correlation peak corresponding to the average displacement of particles across the subregion must be identified. Noise on the images and particle dropout result in misidentification of the true correlation peak. The subsequent velocity vector maps contain spurious vectors where the displacement peaks have been improperly identified. Typically these spurious vectors are replaced by a weighted average of the neighboring vectors, thereby decreasing the independence of the measurements. In this work, fuzzy logic techniques are used to determine the true

  13. MESSENGER: Exploring Mercury's Magnetosphere

    NASA Astrophysics Data System (ADS)

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

    2007-08-01

    The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (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. 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 beneath the solid surface 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 recycling of neutrals and ions among 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, and pick-up of planetary ions all playing roles in the generation of field-aligned electric currents. However, these field

  14. 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

  15. 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.

  16. A particle astrophysics magnet spectrometer facility for Space Station

    NASA Technical Reports Server (NTRS)

    Ormes, J. F.; Israel, M. H.; Mewaldt, R.; Wiedenbeck, M.

    1987-01-01

    Planning for and design tradeoff studies related to the particle astrophysics magnet spectrometer known as Astromag are presented. This facility is being planned for the Space Station Freedom and address questions regarding the origin and acceleration of cosmic rays, explore the synthesis of elements by making detailed measurements of cosmic ray isotopic composition, and search for evidence of antimatter and other cosmologically significant particles. This work was supported by an international study team which includes particle physicists and cosmic ray physicists.

  17. A Pragmatic Constraint on Particle Conversion in Japanese.

    ERIC Educational Resources Information Center

    Horie, Kaoru; Saito, Noriko

    The grammatical phenomenon in Japanese known as Ga-No conversion is examined. In this phenomenon, the nominative particle "ga" can be converted to genitive particle "no" in embedded sentences with a nominal head such as a relative clause or complementary clause. A pragmatic constraint to this conversion that has not previously been explored is…

  18. Microbial partitioning to settleable particles in stormwater.

    PubMed

    Characklis, Gregory W; Dilts, Mackenzie J; Simmons, Otto D; Likirdopulos, Christina A; Krometis, Leigh-Anne H; Sobsey, Mark D

    2005-05-01

    The degree to which microbes in the water column associate with settleable particles has important implications for microbial transport in receiving waters, as well as for microbial removal via sedimentation (i.e. detention basins). The partitioning behavior of several bacterial, protozoan and viral indicator organisms is explored in three urban streams under both storm and dry weather conditions. The fraction of organisms associated with settleable particles in stormwater is estimated through use of a centrifugation technique which is calibrated using suspensions of standard particles (e.g., glass, latex). The fraction of organisms associated with settleable particles varies by type of microbe, and the partitioning behavior of each organism generally changes between dry weather and storm conditions. Bacterial indicator organisms (fecal coliforms, Escherichia coli, enterococci) exhibited relatively consistent behavior, with an average of 20-35% of organisms associated with these particles in background samples and 30-55% in storm samples. Clostridium perfringens spores exhibited the highest average level of particle association, with storm values varying from 50% to 70%. Results related to total coliphage partitioning were more variable, with 20-60% associated with particles during storms. These estimates should be valuable in surface water quality modeling efforts, many of which currently assume that all microbes exist as free (unattached) organisms.

  19. Gaussian particle flow implementation of PHD filter

    NASA Astrophysics Data System (ADS)

    Zhao, Lingling; Wang, Junjie; Li, Yunpeng; Coates, Mark J.

    2016-05-01

    Particle filter and Gaussian mixture implementations of random finite set filters have been proposed to tackle the issue of jointly estimating the number of targets and their states. The Gaussian mixture PHD (GM-PHD) filter has a closed-form expression for the PHD for linear and Gaussian target models, and extensions using the extended Kalman filter or unscented Kalman Filter have been developed to allow the GM-PHD filter to accommodate mildly nonlinear dynamics. Errors resulting from linearization or model mismatch are unavoidable. A particle filter implementation of the PHD filter (PF-PHD) is more suitable for nonlinear and non-Gaussian target models. The particle filter implementations are much more computationally expensive and performance can suffer when the proposal distribution is not a good match to the posterior. In this paper, we propose a novel implementation of the PHD filter named the Gaussian particle flow PHD filter (GPF-PHD). It employs a bank of particle flow filters to approximate the PHD; these play the same role as the Gaussian components in the GM-PHD filter but are better suited to non-linear dynamics and measurement equations. Using the particle flow filter allows the GPF-PHD filter to migrate particles to the dense regions of the posterior, which leads to higher efficiency than the PF-PHD. We explore the performance of the new algorithm through numerical simulations.

  20. Electrohydrodynamics of a particle-covered drop

    NASA Astrophysics Data System (ADS)

    Ouriemi, Malika; Vlahovska, Petia

    2014-11-01

    We study the dynamics of a drop nearly-completely covered with a particle monolayer in a uniform DC electric field. The weakly conducting fluid system consists of a silicon oil drop suspended in castor oil. A broad range of particle sizes, conductivities, and shapes is explored. In weak electric fields, the presence of particles increases drop deformation compared to a particle-free drop and suppresses the electrohydrodynamic flow. Very good agreement is observed between the measured drop deformation and the small deformation theory derived for surfactant-laden drops (Nganguia et al., 2013). In stronger electric fields, where drops are expected to undergo Quincke rotation (Salipante and Vlahovska, 2010), the presence of the particles greatly decreases the threshold for rotation and the stationary tilted drop configuration observed for clean drop is replaced by a spinning drop with either a wobbling inclination or a very low inclination. These behaviors resemble the predicted response of rigid ellipsoids in uniform electric fields. At even stronger electric fields, the particles can form dynamic wings or the drop implodes. The similar behavior of particle-covered and surfactant-laden drops provides new insights into understanding stability of Pickering emulsions. Supported by NSF-CBET 1437545.

  1. CLASHING BEAM PARTICLE ACCELERATOR

    DOEpatents

    Burleigh, R.J.

    1961-04-11

    A charged-particle accelerator of the proton synchrotron class having means for simultaneously accelerating two separate contra-rotating particle beams within a single annular magnet structure is reported. The magnet provides two concentric circular field regions of opposite magnetic polarity with one field region being of slightly less diameter than the other. The accelerator includes a deflector means straddling the two particle orbits and acting to collide the two particle beams after each has been accelerated to a desired energy. The deflector has the further property of returning particles which do not undergo collision to the regular orbits whereby the particles recirculate with the possibility of colliding upon subsequent passages through the deflector.

  2. Methods for forming particles

    DOEpatents

    Fox, Robert V.; Zhang, Fengyan; Rodriguez, Rene G.; Pak, Joshua J.; Sun, Chivin

    2016-06-21

    Single source precursors or pre-copolymers of single source precursors are subjected to microwave radiation to form particles of a I-III-VI.sub.2 material. Such particles may be formed in a wurtzite phase and may be converted to a chalcopyrite phase by, for example, exposure to heat. The particles in the wurtzite phase may have a substantially hexagonal shape that enables stacking into ordered layers. The particles in the wurtzite phase may be mixed with particles in the chalcopyrite phase (i.e., chalcopyrite nanoparticles) that may fill voids within the ordered layers of the particles in the wurtzite phase thus produce films with good coverage. In some embodiments, the methods are used to form layers of semiconductor materials comprising a I-III-VI.sub.2 material. Devices such as, for example, thin-film solar cells may be fabricated using such methods.

  3. Precision gap particle separator

    DOEpatents

    Benett, William J.; Miles, Robin; Jones, II., Leslie M.; Stockton, Cheryl

    2004-06-08

    A system for separating particles entrained in a fluid includes a base with a first channel and a second channel. A precision gap connects the first channel and the second channel. The precision gap is of a size that allows small particles to pass from the first channel into the second channel and prevents large particles from the first channel into the second channel. A cover is positioned over the base unit, the first channel, the precision gap, and the second channel. An port directs the fluid containing the entrained particles into the first channel. An output port directs the large particles out of the first channel. A port connected to the second channel directs the small particles out of the second channel.

  4. Particle Swarm Optimization

    NASA Technical Reports Server (NTRS)

    Venter, Gerhard; Sobieszczanski-Sobieski Jaroslaw

    2002-01-01

    The purpose of this paper is to show how the search algorithm known as particle swarm optimization performs. Here, particle swarm optimization is applied to structural design problems, but the method has a much wider range of possible applications. The paper's new contributions are improvements to the particle swarm optimization algorithm and conclusions and recommendations as to the utility of the algorithm, Results of numerical experiments for both continuous and discrete applications are presented in the paper. The results indicate that the particle swarm optimization algorithm does locate the constrained minimum design in continuous applications with very good precision, albeit at a much higher computational cost than that of a typical gradient based optimizer. However, the true potential of particle swarm optimization is primarily in applications with discrete and/or discontinuous functions and variables. Additionally, particle swarm optimization has the potential of efficient computation with very large numbers of concurrently operating processors.

  5. The Sisyphus particle detector

    NASA Technical Reports Server (NTRS)

    Soberman, R. K.

    1974-01-01

    The particle measurement subsystem planned for the MJS 77 mission is described. Scientific objectives with respect to Saturn's rings are as follows: (1) measure particles outside the visible rings, including particulates orbiting in more distant rings and particles scattered out of visible rings, (2) measure meteoroid environment in vicinity of Saturn, and (3) develop an understanding of the dynamics of the rings with respect to their collisional interaction with the environment.

  6. Detecting Space Dust Particles

    NASA Technical Reports Server (NTRS)

    Kinard, William H.; Humes, Donald H.; Kassel, Philip C., Jr.; Wortman, Jim; Singer, S. Fred; Stanley, John

    1988-01-01

    Technique records times specific craters formed in targets exposed in space and permits determination of direction in which impacting particles traveled at times of impacts. MOS capacitor is short-circuited by impact of particle striking at high speed. After recovery of targets from space, compositions of impacting particles established through post-flight laboratory analyses of residual materials in craters. On earth technique has industrial and military uses in detection of fragments driven by explosions. Studies of orbital dynamics of particles produced by solid-propellant rocket-motor firings in space made using technique.

  7. Vaporizing particle velocimeter

    NASA Technical Reports Server (NTRS)

    Weinstein, Leonard M. (Inventor)

    1992-01-01

    A velocimeter measures flow characteristics of a flow traveling through a chamber in a given direction. Tracer particles are entrained in the flow and a source of radiant energy produces an output stream directed transversely to the chamber, having a sufficient intensity to vaporize the particles as they pass through the output stream. Each of the vaporized particles explodes to produce a shock wave and a hot core, and a flow visualization system tracks the motion of the hot cores and shock waves to measure the velocity of each tracer particle and the temperature of the flow around the tracer.

  8. Review of Particle Physics

    NASA Astrophysics Data System (ADS)

    Beringer, J.; Arguin, J.-F.; Barnett, R. M.; Copic, K.; Dahl, O.; Groom, D. E.; Lin, C.-J.; Lys, J.; Murayama, H.; Wohl, C. G.; Yao, W.-M.; Zyla, P. A.; Amsler, C.; Antonelli, M.; Asner, D. M.; Baer, H.; Band, H. R.; Basaglia, T.; Bauer, C. W.; Beatty, J. J.; Belousov, V. I.; Bergren, E.; Bernardi, G.; Bertl, W.; Bethke, S.; Bichsel, H.; Biebel, O.; Blucher, E.; Blusk, S.; Brooijmans, G.; Buchmueller, O.; Cahn, R. N.; Carena, M.; Ceccucci, A.; Chakraborty, D.; Chen, M.-C.; Chivukula, R. S.; Cowan, G.; D'Ambrosio, G.; Damour, T.; de Florian, D.; de Gouvêa, A.; DeGrand, T.; de Jong, P.; Dissertori, G.; Dobrescu, B.; Doser, M.; Drees, M.; Edwards, D. A.; Eidelman, S.; Erler, J.; Ezhela, V. V.; Fetscher, W.; Fields, B. D.; Foster, B.; Gaisser, T. K.; Garren, L.; Gerber, H.-J.; Gerbier, G.; Gherghetta, T.; Golwala, S.; Goodman, M.; Grab, C.; Gritsan, A. V.; Grivaz, J.-F.; Grünewald, M.; Gurtu, A.; Gutsche, T.; Haber, H. E.; Hagiwara, K.; Hagmann, C.; Hanhart, C.; Hashimoto, S.; Hayes, K. G.; Heffner, M.; Heltsley, B.; Hernández-Rey, J. J.; Hikasa, K.; Höcker, A.; Holder, J.; Holtkamp, A.; Huston, J.; Jackson, J. D.; Johnson, K. F.; Junk, T.; Karlen, D.; Kirkby, D.; Klein, S. R.; Klempt, E.; Kowalewski, R. V.; Krauss, F.; Kreps, M.; Krusche, B.; Kuyanov, Yu. V.; Kwon, Y.; Lahav, O.; Laiho, J.; Langacker, P.; Liddle, A.; Ligeti, Z.; Liss, T. M.; Littenberg, L.; Lugovsky, K. S.; Lugovsky, S. B.; Mannel, T.; Manohar, A. V.; Marciano, W. J.; Martin, A. D.; Masoni, A.; Matthews, J.; Milstead, D.; Miquel, R.; Mönig, K.; Moortgat, F.; Nakamura, K.; Narain, M.; Nason, P.; Navas, S.; Neubert, M.; Nevski, P.; Nir, Y.; Olive, K. A.; Pape, L.; Parsons, J.; Patrignani, C.; Peacock, J. A.; Petcov, S. T.; Piepke, A.; Pomarol, A.; Punzi, G.; Quadt, A.; Raby, S.; Raffelt, G.; Ratcliff, B. N.; Richardson, P.; Roesler, S.; Rolli, S.; Romaniouk, A.; Rosenberg, L. J.; Rosner, J. L.; Sachrajda, C. T.; Sakai, Y.; Salam, G. P.; Sarkar, S.; Sauli, F.; Schneider, O.; Scholberg, K.; Scott, D.; Seligman, W. G.; Shaevitz, M. H.; Sharpe, S. R.; Silari, M.; Sjöstrand, T.; Skands, P.; Smith, J. G.; Smoot, G. F.; Spanier, S.; Spieler, H.; Stahl, A.; Stanev, T.; Stone, S. L.; Sumiyoshi, T.; Syphers, M. J.; Takahashi, F.; Tanabashi, M.; Terning, J.; Titov, M.; Tkachenko, N. P.; Törnqvist, N. A.; Tovey, D.; Valencia, G.; van Bibber, K.; Venanzoni, G.; Vincter, M. G.; Vogel, P.; Vogt, A.; Walkowiak, W.; Walter, C. W.; Ward, D. R.; Watari, T.; Weiglein, G.; Weinberg, E. J.; Wiencke, L. R.; Wolfenstein, L.; Womersley, J.; Woody, C. L.; Workman, R. L.; Yamamoto, A.; Zeller, G. P.; Zenin, O. V.; Zhang, J.; Zhu, R.-Y.; Harper, G.; Lugovsky, V. S.; Schaffner, P.

    2012-07-01

    This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements from 644 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 112 reviews are many that are new or heavily revised including those on Heavy-Quark and Soft-Collinear Effective Theory, Neutrino Cross Section Measurements, Monte Carlo Event Generators, Lattice QCD, Heavy Quarkonium Spectroscopy, Top Quark, Dark Matter, Vcb & Vub, Quantum Chromodynamics, High-Energy Collider Parameters, Astrophysical Constants, Cosmological Parameters, and Dark Matter.A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov/.The 2012 edition of Review of Particle Physics is published for the Particle Data Group as article 010001 in volume 86 of Physical Review D.This edition should be cited as: J. Beringer et al. (Particle Data Group), Phys. Rev. D 86, 010001 (2012).

  9. Ice particle collisions

    NASA Astrophysics Data System (ADS)

    Sampara, Naresh; Turnbull, Barbara; Hill, Richard; Swift, Michael

    2017-04-01

    Granular interactions of ice occur in a range of geophysical, astrophysical and industrial applications. For example, Saturn's Rings are composed of icy particles from micrometers to kilometres in size - inertial and yet too small to interact gravitationally. In clouds, ice crystals are smashed to pieces before they re-aggregate to for snow floccules in a process that is very much open to interpretation. In a granular flow of ice particles, the energy spent in collisions can lead to localized surface changes and wetting, which in turn can promote aggregation. To understand the induced wetting and its effects, we present two novel experimental methods which provide snippets of insight into the collisional behaviour of macroscopic ice particles. Experiment 1: Microgravity experiments provide minute details of the contact between the ice particles during the collision. A diamagnetic levitation technique, as alternative to the parabolic flight or falling tower experiments, was used to understand the collisional behaviour of individual macroscopic icy bodies. A refrigerated cylinder, that can control ambient conditions, was inserted into the bore of an 18 Tesla superconducting magnet and cooled to -10°C. Initial binary collisions were created, where one 4 mm ice particle was levitated in the magnet bore whilst another particle was dropped vertically from the top of the bore. The trajectories of both particles were captured by high speed video to provide the three-dimensional particle velocities and track the collision outcome. Introducing complexity, multiple particles were levitated in the bore and an azimuthal turbulent air flow introduced, allowing the particles to collide with other particles within a coherent fluid structure (mimicking Saturn's rings, or an eddy in a cloud). In these experiments, a sequence of collisions occur, each one different to the previous one due to the changes in surface characteristics created by the collisions themselves. Aggregation

  10. Bioactivation of particles

    DOEpatents

    Pinaud, Fabien; King, David; Weiss, Shimon

    2011-08-16

    Particles are bioactivated by attaching bioactivation peptides to the particle surface. The bioactivation peptides are peptide-based compounds that impart one or more biologically important functions to the particles. Each bioactivation peptide includes a molecular or surface recognition part that binds with the surface of the particle and one or more functional parts. The surface recognition part includes an amino-end and a carboxy-end and is composed of one or more hydrophobic spacers and one or more binding clusters. The functional part(s) is attached to the surface recognition part at the amino-end and/or said carboxy-end.

  11. Restoring particle phenomenology

    NASA Astrophysics Data System (ADS)

    Valente, Giovanni

    2015-08-01

    No-go theorems are known in the literature to the effect that, in relativistic quantum field theory, particle localizability in the strict sense violates relativistic causality. In order to account for particle phenomenology without particle ontology, Halvorson and Clifton (2002) proposed an approximate localization scheme. In a recent paper, Arageorgis and Stergiou (2013) proved a no-go result that suggests that, even within such a scheme, there would arise act-outcome correlations over the entire spacetime, thereby violating relativistic causality. Here, we show that this conclusion is untenable. In particular, we argue that one can recover particle phenomenology without having to give up relativistic causality.

  12. Dielectrophoretic particle-particle interaction under AC electrohydrodynamic flow conditions.

    PubMed

    Lee, Doh-Hyoung; Yu, Chengjie; Papazoglou, Elisabeth; Farouk, Bakhtier; Noh, Hongseok M

    2011-09-01

    We used the Maxwell stress tensor method to understand dielectrophoretic particle-particle interactions and applied the results to the interpretation of particle behaviors under alternating current (AC) electrohydrodynamic conditions such as AC electroosmosis (ACEO) and electrothermal flow (ETF). Distinct particle behaviors were observed under ACEO and ETF. Diverse particle-particle interactions observed in experiments such as particle clustering, particles keeping a certain distance from each other, chain and disc formation and their rotation, are explained based on the numerical simulation data. The improved understanding of particle behaviors in AC electrohydrodynamic flows presented here will enable researchers to design better particle manipulation strategies for lab-on-a-chip applications.

  13. Recent Research on Lunar Exploration

    NASA Astrophysics Data System (ADS)

    Jun, M.

    2002-01-01

    exploration. There are several kinds of rare gas in the lunar soil such as 3He. 3He is the 'clear' nuclear source for the nuclear energy output. It must accelerate economic development if people can know the distribution and content of the useful elements in lunar soil. The scientific goal of the Chinese lunar exploration is based on to search the lunar useful elements and to understand the lunar conditions. The Scientific detecting method and the payloads of lunar exploration are mentioned. They include the lunar observation and space environment probing in the lunar orbit. content using remote sensing methods. The scientific goal is to gain the lunar map of the content of the lunar useful elements, and to determine the distribution of the different lunar rock. It needs Optical Remote Sensor System (CCD Camera) and μ-Detector (elements Analysis). soil's thickness and the distribution and content of the rare gas in the lunar soil withμ-Detector (elements Analysis)and Micro-Wave Detector system (probing the lunar surface). Micro-Wave Detector system, the LASER meter and the neutron detector if people want to look for any status of H2O on the moon, especially on the south pole of moon. surface and the inside core, The Durpler meter, the electron reflex spectrum meter and the magnetometer are all needed. high-energy particle detector, low energy particle detector can monitor the flux of the solar cosmic-ray and the solar wind, and the magnetometer can describe the change of the magneto-field.

  14. Introduction of Electrostatically Charged Particles into Metal Melts

    NASA Astrophysics Data System (ADS)

    Kudryashova, Olga; Vorozhtsov, Sergey; Stepkina, Maria; Khrustalev, Anton

    2017-09-01

    One of the possible methods to produce composite alloys with improved mechanical characteristics is the modification of metal melts using submicron- or nanosized particles. Different methods, like ultrasonic or vibration processing, have been used to introduce these particles into the metal melt. The introduction of particles into a metal melt is prevented by the poor wettability of the liquid metal. The present study explores the use of electrostatic charge for increasing the wettability of the particles and preventing their agglomeration. The wettability of electrostatically charged particles by the metal melt under the impact of ultrasound has been studied. The relationships between the impact time and the physical and chemical properties of the particles and the melt along with the characteristics of the acoustic radiation have been studied. It was experimentally demonstrated that the introduction of electrostatically charged particles into the metal melt reduces the porosity and the crystal grain size.

  15. 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.

  16. Solar Energetic Particles

    NASA Astrophysics Data System (ADS)

    Király, Péter

    Energetic particles recorded in the Earth environment and in interplanetary space have a multitude of origins, i.e. acceleration and propagation histories. At early days practically all sufficiently energetic particles were considered to have come either from solar flares or from interstellar space. Later on, co-rotating interplanetary shocks, the termination shock of the supersonic solar wind, planetary bow shocks and magnetospheres, and also coronal mass ejections (CME) were recognized as energetic particle sources. It was also recognized that less energetic (suprathermal) particles of solar origin and pick-up ions have also a vital role in giving rise to energetic particles in interplanetary disturbances. The meaning of the term "solar energetic particles" (SEP) is now somewhat vague, but essentially it refers to particles produced in disturbances fairly directly related to solar processes. Variation of intensity fluctuations with energy and with the phase of the solar cycle will be discussed. Particular attention will be given to extremes of time variation, i.e. to very quiet periods and to large events. While quiet-time fluxes are expected to shed light on some basic coronal processes, large events dominate the fluctuation characteristics of cumulated fluence, and the change of that fluctuation with energy and with the phase of the solar cycle may also provide important clues. Mainly ISEE-3 and long-term IMP-8 data will be invoked. Energetic and suprathermal particles that may never escape into interplanetary space may play an important part in heating the corona of the sun.

  17. Interactive Terascale Particle Visualization

    NASA Technical Reports Server (NTRS)

    Ellsworth, David; Green, Bryan; Moran, Patrick

    2004-01-01

    This paper describes the methods used to produce an interactive visualization of a 2 TB computational fluid dynamics (CFD) data set using particle tracing (streaklines). We use the method introduced by Bruckschen et al. [2001] that pre-computes a large number of particles, stores them on disk using a space-filling curve ordering that minimizes seeks, and then retrieves and displays the particles according to the user's command. We describe how the particle computation can be performed using a PC cluster, how the algorithm can be adapted to work with a multi-block curvilinear mesh, and how the out-of-core visualization can be scaled to 296 billion particles while still achieving interactive performance on PG hardware. Compared to the earlier work, our data set size and total number of particles are an order of magnitude larger. We also describe a new compression technique that allows the lossless compression of the particles by 41% and speeds the particle retrieval by about 30%.

  18. Detecting Contaminant Particles Acoustically

    NASA Technical Reports Server (NTRS)

    Wyett, L. M.

    1986-01-01

    Apparatus "listens" for particles in interior of complex turbomachinery. Contact microphones are attached at several points on pump housing. Acoustic transducer also attached to housing to excite entire pump with sound. Frequency of sound is slowly raised until pump resonates. Microphones detect noise of loose particles scraping against pump parts. Such as machining chips in turbopumps or other machinery without disassembly.

  19. Pileup per particle identification

    DOE PAGES

    Bertolini, Daniele; Harris, Philip; Low, Matthew; ...

    2014-10-09

    We propose a new method for pileup mitigation by implementing “pileup per particle identification” (PUPPI). For each particle we first define a local shape α which probes the collinear versus soft diffuse structure in the neighborhood of the particle. The former is indicative of particles originating from the hard scatter and the latter of particles originating from pileup interactions. The distribution of α for charged pileup, assumed as a proxy for all pileup, is used on an event-by-event basis to calculate a weight for each particle. The weights describe the degree to which particles are pileup-like and are used tomore » rescale their four-momenta, superseding the need for jet-based corrections. Furthermore, the algorithm flexibly allows combination with other, possibly experimental, probabilistic information associated with particles such as vertexing and timing performance. We demonstrate the algorithm improves over existing methods by looking at jet pT and jet mass. As a result, we also find an improvement on non-jet quantities like missing transverse energy.« less

  20. Icy Particle Spray

    NASA Image and Video Library

    2010-11-18

    Images obtained by NASA EPOXI mission spacecraft show an active end of the nucleus of comet Hartley 2. Icy particles spew from the surface. Most of these particles are traveling with the nucleus; fluffy nowballs about 3 centimeters to 30 centimeters.

  1. Particle fuel diversion structure

    SciTech Connect

    Eshleman, R. D.

    1985-07-30

    A particle fuel burning furnace has an upper combustion chamber for holding a pile of particle fuel and burning the same from the bottom thereof. The furnace also includes a lower combustion chamber for after-burning combustible gases given off by the burning of solid fuel in the upper chamber and a series of spaced apart vertically-extending passageways arranged in a row and interconnecting the upper and lower chambers for communicating the combustible gases from the upper to the lower chamber. A first improved feature relates to a particle fuel delivery control device which operates an auger for filling the upper chamber with particle fuel to a desired level. A beam of light is transmitted and reflected between a photoelectric cell and reflector respectively of the device. When the particle fuel pile has grown in height during filling to the desired level the light beam is interrupted and filling is terminated. A second improved feature relates to a particle fuel diversion structure positioned in spaced relationship above and overlying the row of passageways. The structure forms a horizontal slot which extends laterally from the passageways which prevents particles of fuel from falling through the passageways and relocates the flame which burns the particle fuel pile from the bottom to a region away from the passageways.

  2. Ambient Tropospheric Particles

    EPA Science Inventory

    Atmospheric particulate matter (PM) is a complex mixture of solid and liquid particles suspended in ambient air (also known as the atmospheric aerosol). Ambient PM arises from a wide-range of sources and/or processes, and consists of particles of different shapes, sizes, and com...

  3. Pileup per particle identification

    SciTech Connect

    Bertolini, Daniele; Harris, Philip; Low, Matthew; Tran, Nhan

    2014-10-09

    We propose a new method for pileup mitigation by implementing “pileup per particle identification” (PUPPI). For each particle we first define a local shape α which probes the collinear versus soft diffuse structure in the neighborhood of the particle. The former is indicative of particles originating from the hard scatter and the latter of particles originating from pileup interactions. The distribution of α for charged pileup, assumed as a proxy for all pileup, is used on an event-by-event basis to calculate a weight for each particle. The weights describe the degree to which particles are pileup-like and are used to rescale their four-momenta, superseding the need for jet-based corrections. Furthermore, the algorithm flexibly allows combination with other, possibly experimental, probabilistic information associated with particles such as vertexing and timing performance. We demonstrate the algorithm improves over existing methods by looking at jet pT and jet mass. As a result, we also find an improvement on non-jet quantities like missing transverse energy.

  4. RESEARCH IN PARTICLE PHYSICS

    SciTech Connect

    Kearns, Edward

    2013-07-12

    This is the final report for the Department of Energy Grant to Principal Investigators in Experimental and Theoretical Particle Physics at Boston University. The research performed was in the Energy Frontier at the LHC, the Intensity Frontier at Super-Kamiokande and T2K, the Cosmic Frontier and detector R&D in dark matter detector development, and in particle theory.

  5. Ambient Tropospheric Particles

    EPA Science Inventory

    Atmospheric particulate matter (PM) is a complex mixture of solid and liquid particles suspended in ambient air (also known as the atmospheric aerosol). Ambient PM arises from a wide-range of sources and/or processes, and consists of particles of different shapes, sizes, and com...

  6. Particle impact location detector

    NASA Technical Reports Server (NTRS)

    Auer, S. O.

    1974-01-01

    Detector includes delay lines connected to each detector surface strip. When several particles strike different strips simultaneously, pulses generated by each strip are time delayed by certain intervals. Delay time for each strip is known. By observing time delay in pulse, it is possible to locate strip that is struck by particle.

  7. Anisotropic Particles in Turbulence

    NASA Astrophysics Data System (ADS)

    Voth, Greg A.; Soldati, Alfredo

    2017-01-01

    Anisotropic particles are common in many industrial and natural turbulent flows. When these particles are small and neutrally buoyant, they follow Lagrangian trajectories while exhibiting rich orientational dynamics from the coupling of their rotation to the velocity gradients of the turbulence field. This system has proven to be a fascinating application of the fundamental properties of velocity gradients in turbulence. When particles are not neutrally buoyant, they experience preferential concentration and very different preferential alignment than neutrally buoyant tracer particles. A vast proportion of the parameter range of anisotropic particles in turbulence is still unexplored, with most existing research focusing on the simple foundational cases of axisymmetric ellipsoids at low concentrations in homogeneous isotropic turbulence and in turbulent channel flow. Numerical simulations and experiments have recently developed a fairly comprehensive picture of alignment and rotation in these cases, and they provide an essential foundation for addressing more complex problems of practical importance. Macroscopic effects of nonspherical particle dynamics include preferential concentration in coherent structures and drag reduction by fiber suspensions. We review the models used to describe nonspherical particle motion, along with numerical and experimental methods for measuring particle dynamics.

  8. Petascale Flow Simulations Using Particles and Grids

    NASA Astrophysics Data System (ADS)

    Koumoutsakos, Petros

    2014-11-01

    How to chose the discretization of flow models in order to harness the power of available computer architectures? Our group explores this question for particle (vortex methods, molecular and dissipative particle dynamics) and grid based (finite difference, finite volume) discretisations for flow simulations across scales. I will discuss methodologies to transition between these methods and their implementation in massively parallel computer architectures. I will present simulations ranging from flows of cells in microfluidic channels to cloud cavitation collapse at 14.5 PFLOP/s. This research was supported by the European Research Council, the Swiss National Science Foundation and the Swiss National Supercomputing Center.

  9. Computer Models Simulate Fine Particle Dispersion

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Through a NASA Seed Fund partnership with DEM Solutions Inc., of Lebanon, New Hampshire, scientists at Kennedy Space Center refined existing software to study the electrostatic phenomena of granular and bulk materials as they apply to planetary surfaces. The software, EDEM, allows users to import particles and obtain accurate representations of their shapes for modeling purposes, such as simulating bulk solids behavior, and was enhanced to be able to more accurately model fine, abrasive, cohesive particles. These new EDEM capabilities can be applied in many industries unrelated to space exploration and have been adopted by several prominent U.S. companies, including John Deere, Pfizer, and Procter & Gamble.

  10. Particle size reduction of propellants by cryocycling

    SciTech Connect

    Whinnery, L.; Griffiths, S.; Lipkin, J.

    1995-05-01

    Repeated exposure of a propellant to liquid nitrogen causes thermal stress gradients within the material resulting in cracking and particle size reduction. This process is termed cryocycling. The authors conducted a feasibility study, combining experiments on both inert and live propellants with three modeling approaches. These models provided optimized cycle times, predicted ultimate particle size, and allowed crack behavior to be explored. Process safety evaluations conducted separately indicated that cryocycling does not increase the sensitivity of the propellants examined. The results of this study suggest that cryocycling is a promising technology for the demilitarization of tactical rocket motors.

  11. HIGH ENERGY PARTICLE ACCELERATOR

    DOEpatents

    Courant, E.D.; Livingston, M.S.; Snyder, H.S.

    1959-04-14

    An improved apparatus is presented for focusing charged particles in an accelerator. In essence, the invention includes means for establishing a magnetic field in discrete sectors along the path of moving charged particles, the magnetic field varying in each sector in accordance with the relation. B = B/ sub 0/ STAln (r-r/sub 0/)/r/sub 0/!, where B/sub 0/ is the value of the magnetic field at the equilibrium orbit of radius r/sub 0/ of the path of the particles, B equals the magnetic field at the radius r of the chamber and n equals the magnetic field gradient index, the polarity of n being abruptly reversed a plurality of times as the particles travel along their arcuate path. With this arrangement, the particles are alternately converged towards the axis of their equillbrium orbit and diverged therefrom in successive sectors with a resultant focusing effect.

  12. Review of particle physics

    DOE PAGES

    Olive, K. A.

    2016-10-01

    The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders,more » Probability and Statistics. As a result, among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation.« less

  13. Review of particle physics

    SciTech Connect

    Olive, K. A.

    2016-10-01

    The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. As a result, among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation.

  14. Imaging alpha particle detector

    DOEpatents

    Anderson, David F.

    1985-01-01

    A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  15. Imaging alpha particle detector

    DOEpatents

    Anderson, D.F.

    1980-10-29

    A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  16. Elementary particles and cosmology

    NASA Astrophysics Data System (ADS)

    Dobrolyubov, M. I.; Ignatev, A. Yu.; Shaposhnikov, M. E.

    1988-12-01

    A series of lectures is devoted to actual problems which arise at the junction of elementary particle physics and cosmology. A brief review is given to the standard theory of hot universe and scenario of inflationary universe, modern state of the problem of baryon universe asymmetry and possible new mechanisms of this asymmetry formation. The possibility of construction of cosmological models on the basis of supersymmetric theories is considered: qualitative evaluation of the modern density of relic particles, cosmological restrictions for the mass of the lightest particle, astrophysical restrictions for the coupling constant of weakly interacting particles and matter are given. A perspective direction of search for light particles in light hadron decays is mentioned.

  17. Particle Analysis Pitfalls

    NASA Technical Reports Server (NTRS)

    Hughes, David; Dazzo, Tony

    2007-01-01

    This viewgraph presentation reviews the use of particle analysis to assist in preparing for the 4th Hubble Space Telescope (HST) Servicing mission. During this mission the Space Telescope Imaging Spectrograph (STIS) will be repaired. The particle analysis consisted of Finite element mesh creation, Black-body viewfactors generated using I-DEAS TMG Thermal Analysis, Grey-body viewfactors calculated using Markov method, Particle distribution modeled using an iterative Monte Carlo process, (time-consuming); in house software called MASTRAM, Differential analysis performed in Excel, and Visualization provided by Tecplot and I-DEAS. Several tests were performed and are reviewed: Conformal Coat Particle Study, Card Extraction Study, Cover Fastener Removal Particle Generation Study, and E-Graf Vibration Particulate Study. The lessons learned during this analysis are also reviewed.

  18. Review of particle physics

    SciTech Connect

    Olive, K. A.

    2016-10-01

    The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. As a result, among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation.

  19. DEM Particle Fracture Model

    SciTech Connect

    Zhang, Boning; Herbold, Eric B.; Homel, Michael A.; Regueiro, Richard A.

    2015-12-01

    An adaptive particle fracture model in poly-ellipsoidal Discrete Element Method is developed. The poly-ellipsoidal particle will break into several sub-poly-ellipsoids by Hoek-Brown fracture criterion based on continuum stress and the maximum tensile stress in contacts. Also Weibull theory is introduced to consider the statistics and size effects on particle strength. Finally, high strain-rate split Hopkinson pressure bar experiment of silica sand is simulated using this newly developed model. Comparisons with experiments show that our particle fracture model can capture the mechanical behavior of this experiment very well, both in stress-strain response and particle size redistribution. The effects of density and packings o the samples are also studied in numerical examples.

  20. 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.

  1. 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.

  2. 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…

  3. 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…

  4. Birth Control Explorer

    MedlinePlus

    ... Relationships STIs Media Facebook Twitter Tumblr Shares · 472 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 ...

  5. [Space Exploration Initiative

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Future Mars exploration missions and operations are discussed using computer animation along with proposed vehicles and equipment, for example, a Mars surface land rover. There is a Presidential Address by President George Bush where he discusses future goals for space exploration. This video also outlines the Outreach Program, which offers the public the chance to suggest new ideas for space research and exploration.

  6. Emergence and Utility of Nonspherical Particles in Biomedicine

    PubMed Central

    Fish, Margaret B.; Thompson, Alex J.; Fromen, Catherine A.; Eniola-Adefeso, Omolola

    2016-01-01

    The importance of the size of targeted, spherical drug carriers has been previously explored and reviewed. Particle shape has emerged as an equally important parameter in determining the in vivo journey and efficiency of drug carrier systems. Researchers have invented techniques to better control the geometry of particles of many different materials, which have allowed for exploration of the role of particle geometry in the phases of drug delivery. The important biological processes include clearance by the immune system, trafficking to the target tissue, margination to the endothelial surface, interaction with the target cell, and controlled release of a payload. The review of current literature herein supports that particle shape can be altered to improve a system’s targeting efficiency. Non-spherical particles can harness the potential of targeted drug carriers by enhancing targeted site accumulation while simultaneously decreasing side effects and mitigating some limitations faced by spherical carriers. PMID:27182109

  7. Radial Concentration of Particles within an Evolving Protoplanetary Disk

    NASA Astrophysics Data System (ADS)

    Hughes, Anna L.; Armitage, P. J.

    2010-10-01

    Recent theories of planetesimal formation contend that formation via gravitational and or fluid instabilities may occur in regions of enhanced solids content. While settling of solids toward a protoplanetary disk midplane is probably an important component of such concentration, because of disk turbulence it is insufficient to drive collapse into larger bodies. The next logical concentration mechanism is then global concentration of solids via radial drift of particles, and this has been explored to a degree with promising results. Here we combine radial drift of particles with radial diffusion, which acts to counteract the effects of inward particle flux. We use a stocastic model to track the radial mass distribution of a particle ensemble within an evolving protoplanetary disk using a range of particle sizes, and explore the feasibility of globally concentrating solids to a degree that could lead to enhanced planetesimal formation.

  8. Polarization dependent particle dynamics in simple traps

    NASA Astrophysics Data System (ADS)

    Yifat, Yuval; Sule, Nishant; Figliozzi, Patrick; Scherer, Norbert F.

    2016-09-01

    Optical trapping has proved to be a valuable research tool in a wide range of fields including physics, chemistry, biological and materials science. The ability to precisely localize individual colloidal particles in a three-dimensional location has been highly useful for understanding soft matter phenomena and inter-particle interactions. It also holds great promise for nanoscale fabrication and ultra-sensitive sensing by enabling precise positioning of specific material building blocks. In this presentation we discuss our research on the effect of the polarization state of the incident laser on the trapping of nanoscale particles. The polarization of the incident light has a pronounced effect on particle behavior even for the simple case of two plasmonic silver nano-particles in a Gaussian trap,. When the incident light is linearly polarized, the particles form an optically induced dimer that is stably oriented along the direction of polarization. However, nanoparticle dimers and trimmers exhibit structural instabilities and novel dynamics when trapped with focused beams of circularly polarized light. The observed dynamics suggest electrodynamic and hydrodynamic coupling. We explore the electrodynamic phenomena experimentally and theoretically and discuss further examples of polarization controlled trapping.

  9. Designing Jammed Materials from the Particle Up

    NASA Astrophysics Data System (ADS)

    Miskin, Marc

    2015-03-01

    Identifying which microscopic features produce a desired macroscopic behavior is a problem at the forefront of materials science. This task is materials design, and within it, new challenges have emerged from tailoring packings of particles jammed into a rigid state. For these materials, particle shape is a key parameter by which the response of a packing can be tuned. Yet designing via shape faces two unique complications: first there is no general theory that calculates the response of an aggregate given a particle shape, and second, there is no straightforward way to explore the space of all particle geometries. This talk summarizes recent results that address these challenges to design jammed materials from the particle up. It shows how simulations, experiments, and state-of-the-art optimization engines come together to form a complete system that identifies extreme materials. As examples, it will show how this system can create particle shapes that form the stiffest, softest, densest, loosest, most dissipative and strain-stiffening aggregates. Finally, it will discuss the how these results relate to the general task of materials design and the exciting possibilities associated with optimizing, tuning and rationally constructing new breeds of jammed materials.

  10. Particle Acceleration by Cme-driven Shock Waves

    NASA Technical Reports Server (NTRS)

    Reames, Donald V.

    1999-01-01

    In the largest solar energetic particle (SEP) events, acceleration occurs at shock waves driven out from the Sun by coronal mass ejections (CMEs). Peak particle intensities are a strong function of CME speed, although the intensities, spectra, and angular distributions of particles escaping the shock are highly modified by scattering on Alfven waves produced by the streaming particles themselves. Element abundances vary in complex ways because ions with different values of Q/A resonate with different parts of the wave spectrum, which varies with space and time. Just recently, we have begun to model these systematic variations theoretically and to explore other consequences of proton-generated waves.

  11. Motion of particles near a magnetized tidal charged black hole

    NASA Astrophysics Data System (ADS)

    Sharif, M.; Kousar, Lubna

    2017-07-01

    This paper is devoted to study the effects of tidal charge on the motion of both neutral as well as charged particles around a magnetized tidal charged black hole. We analyze the innermost stable circular orbits and conditions for escape velocity. In order to discuss stability of orbits, we explore Lyapunov exponent and effective force on the particle. The center of mass energy of the interacting particles is studied in the presence/absence of external magnetic field. We conclude that the external magnetic field as well as tidal charge has a great influence on the particle's motion.

  12. 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.

  13. Asteroid exploration and utilization: The Hawking explorer

    NASA Astrophysics Data System (ADS)

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

    1991-12-01

    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.

  14. A PC-based magnetometer-only attitude and rate determination system for gyroless spacecraft

    NASA Technical Reports Server (NTRS)

    Challa, M.; Natanson, G.; Deutschmann, J.; Galal, K.

    1995-01-01

    This paper describes a prototype PC-based system that uses measurements from a three-axis magnetometer (TAM) to estimate the state (three-axis attitude and rates) of a spacecraft given no a priori information other than the mass properties. The system uses two algorithms that estimate the spacecraft's state - a deterministic magnetic-field only algorithm and a Kalman filter for gyroless spacecraft. The algorithms are combined by invoking the deterministic algorithm to generate the spacecraft state at epoch using a small batch of data and then using this deterministic epoch solution as the initial condition for the Kalman filter during the production run. System input comprises processed data that includes TAM and reference magnetic field data. Additional information, such as control system data and measurements from line-of-sight sensors, can be input to the system if available. Test results are presented using in-flight data from two three-axis stabilized spacecraft: Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) (gyroless, Sun-pointing) and Earth Radiation Budget Satellite (ERBS) (gyro-based, Earth-pointing). The results show that, using as little as 700 s of data, the system is capable of accuracies of 1.5 deg in attitude and 0.01 deg/s in rates; i.e., within SAMPEX mission requirements.

  15. Review of Particle Properties

    NASA Astrophysics Data System (ADS)

    Hagiwara, K.; Hikasa, K.; Nakamura, K.; Tanabashi, M.; Aguilar-Benitez, M.; Amsler, C.; Barnett, R. M.; Burchat, P. R.; Carone, C. D.; Caso, C.; Conforto, G.; Dahl, O.; Doser, M.; Eidelman, S.; Feng, J. L.; Gibbons, L.; Goodman, M.; Grab, C.; Groom, D. E.; Gurtu, A.; Hayes, K. G.; Herna`Ndez-Rey, J. J.; Honscheid, K.; Kolda, C.; Mangano, M. L.; Manley, D. M.; Manohar, A. V.; March-Russell, J.; Masoni, A.; Miquel, R.; Mönig, K.; Murayama, H.; Navas, S.; Olive, K. A.; Pape, L.; Patrignani, C.; Piepke, A.; Roos, M.; Terning, J.; Törnqvist, N. A.; Trippe, T. G.; Vogel, P.; Wohl, C. G.; Workman, R. L.; Yao, W.-M.; Armstrong, B.; Gee, P. S.; Lugovsky, K. S.; Lugovsky, S. B.; Lugovsky, V. S.; Artuso, M.; Asner, D.; Babu, K. S.; Barberio, E.; Battaglia, M.; Bichsel, H.; Biebel, O.; Bloch, P.; Cahn, R. N.; Cattai, A.; Chivukula, R. S.; Cousins, R. D.; Cowan, G.; Damour, T.; Desler, K.; Donahue, R. J.; Edwards, D. A.; Elvira, V. D.; Erler, J.; Ezhela, V. V.; Fasso`, A.; Fetscher, W.; Fields, B. D.; Foster, B.; Froidevaux, D.; Fukugita, M.; Gaisser, T. K.; Garren, L.; Gerber, H.-J.; Gilman, F. J.; Haber, H. E.; Hagmann, C.; Hewett, J.; Hinchliffe, I.; Hogan, C. J.; Höhler, G.; Igo-Kemenes, P.; Jackson, J. D.; Johnson, K. F.; Karlen, D.; Kayser, B.; Klein, S. R.; Kleinknecht, K.; Knowles, I. G.; Kreitz, P.; Kuyanov, Yu. V.; Landua, R.; Langacker, P.; Littenberg, L.; Martin, A. D.; Nakada, T.; Narain, M.; Nason, P.; Peacock, J. A.; Quinn, H. R.; Raby, S.; Raffelt, G.; Razuvaev, E. A.; Renk, B.; Rolandi, L.; Ronan, M. T.; Rosenberg, L. J.; Sachrajda, C. T.; Sanda, A. I.; Sarkar, S.; Schmitt, M.; Schneider, O.; Scott, D.; Seligman, W. G.; Shaevitz, M. H.; Sjöstrand, T.; Smoot, G. F.; Spanier, S.; Spieler, H.; Spooner, N. J. C.; Srednicki, M.; Stahl, A.; Stanev, T.; Suzuki, M.; Tkachenko, N. P.; Valencia, G.; van Bibber, K.; Vincter, M. G.; Ward, D. R.; Webber, B. R.; Whalley, M.; Wolfenstein, L.; Womersley, J.; Woody, C. L.; Zenin, O. V.

    2002-07-01

    This biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 2205 new measurements from 667 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. This edition features expanded coverage of CP violation in B mesons and of neutrino oscillations. For the first time we cover searches for evidence of extra dimensions (both in the particle listings and in a new review). Another new review is on Grand Unified Theories. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.

  16. Apparatus for measuring particle properties

    DOEpatents

    Rader, D.J.; Castaneda, J.N.; Grasser, T.W.; Brockmann, J.E.

    1998-08-11

    An apparatus is described for determining particle properties from detected light scattered by the particles. The apparatus uses a light beam with novel intensity characteristics to discriminate between particles that pass through the beam and those that pass through an edge of the beam. The apparatus can also discriminate between light scattered by one particle and light scattered by multiple particles. The particle`s size can be determined from the intensity of the light scattered. The particle`s velocity can be determined from the elapsed time between various intensities of the light scattered. 11 figs.

  17. Biomimetic particles as therapeutics.

    PubMed

    Meyer, Randall A; Sunshine, Joel C; Green, Jordan J

    2015-09-01

    In recent years, there have been major advances in the development of novel nanoparticle- and microparticle-based therapeutics. An emerging paradigm is the incorporation of biomimetic features into these synthetic therapeutic constructs to enable them to better interface with biological systems. Through the control of size, shape, and material consistency, particle cores have been generated that better mimic natural cells and viruses. In addition, there have been significant advances in biomimetic surface functionalization of particles through the integration of bio-inspired artificial cell membranes and naturally derived cell membranes. Biomimetic technologies enable therapeutic particles to have increased potency to benefit human health.

  18. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-01-01

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  19. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-09-02

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  20. Biomimetic Particles as Therapeutics

    PubMed Central

    Green, Jordan J.

    2015-01-01

    In recent years, there have been major advances in the development of novel nanoparticle and microparticle-based therapeutics. An emerging paradigm is the incorporation of biomimetic features into these synthetic therapeutic constructs to enable them to better interface with biological systems. Through the control of size, shape, and material consistency, particle cores have been generated that better mimic natural cells and viruses. In addition, there have been significant advances in biomimetic surface functionalization of particles through the integration of bio-inspired artificial cell membranes and naturally derived cell membranes. Biomimetic technologies enable therapeutic particles to have increased potency to benefit human health. PMID:26277289

  1. 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.

  2. Solitary waves in particle beams

    SciTech Connect

    Bisognano, J.J.

    1996-07-01

    Since space charge waves on a particle beam exhibit both dispersive and nonlinear character, solitary waves or solitons are possible. Dispersive, nonlinear wave propagation in high current beams is found to be similar to ion-acoustic waves in plasmas with an analogy between Debye screening and beam pipe shielding. Exact longitudinal solitary wave propagation is found for potentials associated with certain transverse distributions which fill the beam pipe. For weak dispersion, the waves satisfy the Korteweg-deVries (KdV) equation, but for strong dispersion they exhibit breaking. More physically realizable distributions which do not fill the beam pipe are investigated and shown to also satisfy a KdV equation for weak dispersion if averaging over rapid transverse motion is physically justified. Scaling laws are presented to explore likely parameter regimes where these phenomena may be observed experimentally.

  3. Discrete particle swarm optimization with scout particles for library materials acquisition.

    PubMed

    Wu, Yi-Ling; Ho, Tsu-Feng; Shyu, Shyong Jian; Lin, Bertrand M T

    2013-01-01

    Materials acquisition is one of the critical challenges faced by academic libraries. This paper presents an integer programming model of the studied problem by considering how to select materials in order to maximize the average preference and the budget execution rate under some practical restrictions including departmental budget, limitation of the number of materials in each category and each language. To tackle the constrained problem, we propose a discrete particle swarm optimization (DPSO) with scout particles, where each particle, represented as a binary matrix, corresponds to a candidate solution to the problem. An initialization algorithm and a penalty function are designed to cope with the constraints, and the scout particles are employed to enhance the exploration within the solution space. To demonstrate the effectiveness and efficiency of the proposed DPSO, a series of computational experiments are designed and conducted. The results are statistically analyzed, and it is evinced that the proposed DPSO is an effective approach for the studied problem.

  4. Discrete Particle Swarm Optimization with Scout Particles for Library Materials Acquisition

    PubMed Central

    Lin, Bertrand M. T.

    2013-01-01

    Materials acquisition is one of the critical challenges faced by academic libraries. This paper presents an integer programming model of the studied problem by considering how to select materials in order to maximize the average preference and the budget execution rate under some practical restrictions including departmental budget, limitation of the number of materials in each category and each language. To tackle the constrained problem, we propose a discrete particle swarm optimization (DPSO) with scout particles, where each particle, represented as a binary matrix, corresponds to a candidate solution to the problem. An initialization algorithm and a penalty function are designed to cope with the constraints, and the scout particles are employed to enhance the exploration within the solution space. To demonstrate the effectiveness and efficiency of the proposed DPSO, a series of computational experiments are designed and conducted. The results are statistically analyzed, and it is evinced that the proposed DPSO is an effective approach for the studied problem. PMID:24072983

  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. Dynamics of magnetic nano-particle assembly

    NASA Astrophysics Data System (ADS)

    Kondratyev, V. N.

    2010-11-01

    Ferromagnetically coupled nano-particle assembly is analyzed accounting for inter- and intra- particle electronic structures within the randomly jumping interacting moments model including quantum fluctuations due to the discrete levels and disorder. At the magnetic jump anomalies caused by quantization the magnetic state equation and phase diagram are found to indicate an existence of spinodal regions and critical points. Arrays of magnetized nano-particles with multiple magnetic response anomalies are predicted to display some specific features. In a case of weak coupling such arrays exhibit the well-separated instability regions surrounding the anomaly positions. With increasing coupling we observe further structure modification, plausibly, of bifurcation type. At strong coupling the dynamical instability region become wide while the stable regime arises as a narrow islands at small disorders. It is shown that exploring correlations of magnetic noise amplitudes represents convenient analytical tool for quantitative definition, description and study of supermagnetism, as well as self-organized criticality.

  7. Introduction to Particle Acceleration in the Cosmos

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Horwitz, J. L.; Perez, J.; Quenby, J.

    2005-01-01

    Accelerated charged particles have been used on Earth since 1930 to explore the very essence of matter, for industrial applications, and for medical treatments. Throughout the universe nature employs a dizzying array of acceleration processes to produce particles spanning twenty orders of magnitude in energy range, while shaping our cosmic environment. Here, we introduce and review the basic physical processes causing particle acceleration, in astrophysical plasmas from geospace to the outer reaches of the cosmos. These processes are chiefly divided into four categories: adiabatic and other forms of non-stochastic acceleration, magnetic energy storage and stochastic acceleration, shock acceleration, and plasma wave and turbulent acceleration. The purpose of this introduction is to set the stage and context for the individual papers comprising this monograph.

  8. Introduction to Particle Acceleration in the Cosmos

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Horwitz, J. L.; Perez, J.; Quenby, J.

    2005-01-01

    Accelerated charged particles have been used on Earth since 1930 to explore the very essence of matter, for industrial applications, and for medical treatments. Throughout the universe nature employs a dizzying array of acceleration processes to produce particles spanning twenty orders of magnitude in energy range, while shaping our cosmic environment. Here, we introduce and review the basic physical processes causing particle acceleration, in astrophysical plasmas from geospace to the outer reaches of the cosmos. These processes are chiefly divided into four categories: adiabatic and other forms of non-stochastic acceleration, magnetic energy storage and stochastic acceleration, shock acceleration, and plasma wave and turbulent acceleration. The purpose of this introduction is to set the stage and context for the individual papers comprising this monograph.

  9. Particle entry into the equatorial magnetosphere.

    NASA Technical Reports Server (NTRS)

    Fritz, T. A.; Barfield, J. N.; Smith, P. H.; Hoffman, R. A.; Konradi, A.

    1973-01-01

    Explorer-45 data are reviewed which concern the behavior and dynamics of protons associated with the storm-time and quiet-time extraterrestrial ring current at the equatorial plane. The quiet-time proton energy spectrum exhibits a peak in the interval between 100 and 200 keV. During storm conditions, the intensities of the higher energy protons decrease while the intensities of protons from 10 to 100 keV are greatly enhanced, making them the dominant contributor to the storm-time particle energy density. It is shown that during magnetic storms, the ratio of the particle energy density to the magnetic field energy density reaches values greater than unity, and that the plasmasphere has a strong influence on the characteristics of particle injection.

  10. Electron Micro Bursts as a Mechanism of Electron Loss Via Wave-Particle Interactions

    NASA Technical Reports Server (NTRS)

    Kanekal, Shrikanth; Baker, Daniel N.; Fennell, Joseph; Klecker, Berndt; Summerlin, Errol J.

    2012-01-01

    Electron microbursts are rapid fluctuations of electron fluxes occurring on time scales of milliseconds. They are thought be due to scattering into the loss cone by plasma waves of various types from chorus to the recently observed large amplitude whistlers. They may be a major process of loss of realtivistic electrons from the Earth's outer radiation belts. One of the key issues that new mission s such as RBSP will address is to understand the loss of relativistic electrons. The SAMPEX mission launched in 1992 and still collecting data has the HILT sensor onboard with the capability of measuring> 1 MeV electrons with a high time resolution of 20 milliseconds suited admirably for the study of microbursts. We will use the data collected by the HILT for over a decade to characterize the relationship between electron microbursts and macroscopic electron decay lifetimes. With the launch of RBSP it is expected that SAMPEX will continue to collect data and overlap with RBSP. The latter will provide valuable information regarding plasma waves which coupled with low altitude measurements of microbursts may help elucidate details of the physics of electron loss from the radiation belt.

  11. 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

  12. Diffusion in Jammed Particle Packs.

    PubMed

    Bolintineanu, Dan S; Grest, Gary S; Lechman, Jeremy B; Silbert, Leonardo E

    2015-08-21

    Using random walk simulations we explore diffusive transport through monodisperse sphere packings over a range of packing fractions ϕ in the vicinity of the jamming transition at ϕ(c). Various diffusion properties are computed over several orders of magnitude in both time and packing pressure. Two well-separated regimes of normal "Fickian" diffusion, where the mean squared displacement is linear in time, are observed. The first corresponds to diffusion inside individual spheres, while the latter is the long-time bulk diffusion. The intermediate anomalous diffusion regime and the long-time value of the diffusion coefficient are both shown to be controlled by particle contacts, which in turn depend on proximity to ϕ(c). The time required to recover normal diffusion t* scales as (ϕ-ϕ(c))(-0.5) and the long-time diffusivity D(∞)∼(ϕ-ϕ(c))0.5, or D(∞)∼1/t*. It is shown that the distribution of mean first passage times associated with the escape of random walkers between neighboring particles controls both t* and D(∞) in the limit ϕ→ϕ(c).

  13. Quadrupole Induced Resonant Particle Transport

    NASA Astrophysics Data System (ADS)

    Gilson, Erik; Fajans, Joel

    1999-11-01

    We have performed experiments that explore the effects of a magnetic quadrupole field on a pure electron plasma confined in a Malmberg-Penning trap. A model that we have developed describes the shape of the plasma and shows that a certain class of resonant particles follows trajectories that take them out of the plasma. Even though the quadrupole field destroys the cylindrical symmetry of the system, our theory predicts that if the electrons are off resonance, then the lifetime of the plasma will not be greatly affected by the quadrupole field. Our preliminary experimental results show that the shape of the plasma and the plasma lifetime agree with our model. We are investigating the scaling of this behavior with various experimental parameters such as the plasma length, density, and strength of the quadrupole field. In addition to being an example of resonant particle transport, this effect may find practical applications in experiments that plan to use magnetic quadrupole neutral atom traps to confine anti-hydrogen created in double-well positron/anti-proton Malmberg-Penning traps. (ATHENA Collaboration.)

  14. Quadrupole Induced Resonant Particle Transport

    NASA Astrophysics Data System (ADS)

    Gilson, Erik; Fajans, Joel

    1998-11-01

    We have performed experiments that explore the effects of a magnetic quadrupole field on a pure electron plasma confined in a Penning-Malmberg trap. A model that we have developed describes the shape of the plasma and shows that a certain class of resonant particles follows trajectories that take them out of the plasma. Even though the quadrupole field destroys the cylindrical symmetry of the system, our theory predicts that if the electrons are off resonance, then the lifetime of the plasma will not be greatly affected by the quadrupole field. Our preliminary experimental results show that the shape of the plasma and the plasma lifetime agree with our model. We are investigating the scaling of this behavior with various experimental parameters such as the plasma length, density, and strength of the quadrupole field. In addition to being an example of resonant particle transport, this effect may find practical applications in experiments that plan to use magnetic quadrupole neutral atom traps to confine anti-hydrogen created in double-well positron/anti-proton Penning-Malmberg traps. (ATHENA Collaboration.)

  15. Particle Physics Masterclass

    ScienceCinema

    Helio Takai

    2016-07-12

    Students from six local high schools -- Farmingdale, Sachem East, Shoreham, Smithtown East, Ward Melville, and William Floyd -- came to Brookhaven National Laboratory to experience research with particle physicist Helio Takai. They were among more than 6,

  16. Particle Pollution Designations

    EPA Pesticide Factsheets

    This area provides information on the process EPA, the states, and the tribes follow to designate areas as attainment (meeting) or nonattainment (not meeting) the particle pollution air quality standards.

  17. Elementary particle theory

    SciTech Connect

    Marciano, W.J.

    1984-12-01

    The present state of the art in elementary particle theory is reviewed. Topics include quantum electrodynamics, weak interactions, electroweak unification, quantum chromodynamics, and grand unified theories. 113 references. (WHK)

  18. Particle chemistry impactor experiment

    NASA Astrophysics Data System (ADS)

    Pueschel, R. F.; Snetsinger, K. G.; Ferry, G. V.; Goodman, J. K.; Verma, S.

    1990-01-01

    Polar stratospheric cloud (PSC) particles are collected on impactors and studied with regard to physical and chemical properties to help explain the importance of heterogeneous chemical reactions for stratospheric ozone depletion. The nitric, hydrochloric, and sulfuric acid content of stratospheric aerosol particles collected at 18 km altitude was determined. It is suggested that nitric acid is a component of polar stratospheric clouds. This is important for two reasons: (1) it proves that chlorine activation takes place at the surface of PSC particles by converting chemically inert chlorine nitrate to chlorine radicals that can react with ozone; and (2) if the PSC particles are large enough to settle out from the stratosphere, the possibility of nitric acid removal can result in the denitrification of the stratosphere.

  19. Research in particle theory

    SciTech Connect

    Mansouri, F.; Suranyi, P; Wijewardhana, L.C.R.

    1991-10-01

    In the test particle approximation, the scattering amplitude for two-particle scattering in (2+1)-dimensional Chern-Simons-Witten gravity and supergravity was computed and compared to the corresponding metric solutions. The formalism was then extended to the exact gauge theoretic treatment of the two-particle scattering problem and compared to 't Hooft's results from the metric approach. We have studied dynamical symmetry breaking in 2+1 dimensional field theories. We have analyzed strong Extended Technicolor (ETC) models where the ETC coupling is close to a critical value. There are effective scalar fields in each of the theories. We have worked our how such scalar particles can be produced and how they decay. The {phi}{sup 4} field theory was investigated in the Schrodinger representation. The critical behavior was extracted in an arbitrary number of dimensions in second order of a systematic truncation approximation. The correlation exponent agrees with known values within a few percent.

  20. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  1. Particle Physics Masterclass

    SciTech Connect

    Helio Takai

    2009-04-10

    Students from six local high schools -- Farmingdale, Sachem East, Shoreham, Smithtown East, Ward Melville, and William Floyd -- came to Brookhaven National Laboratory to experience research with particle physicist Helio Takai. They were among more than 6,

  2. Accelerating Particles with Plasma

    ScienceCinema

    Litos, Michael; Hogan, Mark

    2016-07-12

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  3. Elementary particle physics

    NASA Technical Reports Server (NTRS)

    Perkins, D. H.

    1986-01-01

    Elementary particle physics is discussed. Status of the Standard Model of electroweak and strong interactions; phenomena beyond the Standard Model; new accelerator projects; and possible contributions from non-accelerator experiments are examined.

  4. Particle Size Analysis.

    ERIC Educational Resources Information Center

    Barth, Howard G.; Sun, Shao-Tang

    1989-01-01

    Presents a review of research focusing on scattering, elution techniques, electrozone sensing, filtration, centrifugation, comparison of techniques, data analysis, and particle size standards. The review covers the period 1986-1988. (MVL)

  5. The packing of particles

    SciTech Connect

    Cumberland, D.J.; Crawford, R.J.

    1987-01-01

    The wide range of information currently available on the packing of particles is brought together in this monograph. The authors' interest in the subject was initially aroused by the question of whether there is an optimum particle size distribution which would maximise the packing density of particles - a question which has attracted the interest of scientists and engineers for centuries. The densification of a powder mass is of relevance in a great many industries, among them the pharmaceutical, ceramic, powder metallurgy and civil engineering industries. In addition, the packing of regular - or irregular - shaped particles is also of relevance to a surprisingly large number of other industries and subject areas, i.e. the foundry industry, nuclear engineering, chemical engineering, crystallography, geology, biology, telecommunications, and so on. Accordingly, this book is written for a wide audience.

  6. Electromagnetic particle simulation codes

    NASA Technical Reports Server (NTRS)

    Pritchett, P. L.

    1985-01-01

    Electromagnetic particle simulations solve the full set of Maxwell's equations. They thus include the effects of self-consistent electric and magnetic fields, magnetic induction, and electromagnetic radiation. The algorithms for an electromagnetic code which works directly with the electric and magnetic fields are described. The fields and current are separated into transverse and longitudinal components. The transverse E and B fields are integrated in time using a leapfrog scheme applied to the Fourier components. The particle pushing is performed via the relativistic Lorentz force equation for the particle momentum. As an example, simulation results are presented for the electron cyclotron maser instability which illustrate the importance of relativistic effects on the wave-particle resonance condition and on wave dispersion.

  7. Particle Size Analysis.

    ERIC Educational Resources Information Center

    Barth, Howard G.; Sun, Shao-Tang

    1989-01-01

    Presents a review of research focusing on scattering, elution techniques, electrozone sensing, filtration, centrifugation, comparison of techniques, data analysis, and particle size standards. The review covers the period 1986-1988. (MVL)

  8. Streams of Charged Particles

    NASA Image and Video Library

    2011-04-28

    This graphic shows the different streams of charged particles inside the bubble around our sun and outside, in the unexplored territory of interstellar space. The heliosheath, where NASA two Voyager spacecraft are now traveling, is shown in red.

  9. Particle chemistry impactor experiment

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Snetsinger, K. G.; Ferry, G. V.; Goodman, J. K.; Verma, S.

    1990-01-01

    Polar stratospheric cloud (PSC) particles are collected on impactors and studied with regard to physical and chemical properties to help explain the importance of heterogeneous chemical reactions for stratospheric ozone depletion. The nitric, hydrochloric, and sulfuric acid content of stratospheric aerosol particles collected at 18 km altitude was determined. It is suggested that nitric acid is a component of polar stratospheric clouds. This is important for two reasons: (1) it proves that chlorine activation takes place at the surface of PSC particles by converting chemically inert chlorine nitrate to chlorine radicals that can react with ozone; and (2) if the PSC particles are large enough to settle out from the stratosphere, the possibility of nitric acid removal can result in the denitrification of the stratosphere.

  10. Alpha-particle diagnostics

    SciTech Connect

    Young, K.M.

    1991-01-01

    This paper will focus on the state of development of diagnostics which are expected to provide the information needed for {alpha}- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence {alpha}-particle birth profile, (2) measurement of the escaping {alpha}-particles and (3) measurement of the confined {alpha}-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by {alpha}-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.

  11. Magnetic Particle Process Improvement

    SciTech Connect

    Hubert, R.R.

    2002-08-13

    The magnetic particle testing process is performed to find linear, surface and near surface discontinuities in ferromagnetic test materials. A wet fluorescent method is used at Honeywell Federal Manufacturing & Technologies (FM&T). This method employs a liquid carrier mixed with iron oxide particles in suspension, and the particles used in the method are coated with a fluorescent dye to make them visible under a black light. The process in its current state employs the use of a tank of liquid solution of a mineral oil carrier with iron oxide particles in suspension. The change to the use of an aerosol delivery system with the same material reduces the amount of waste involved in the process while preserving the sensitivity of the testing, shortens the flowtime for the test, and saves labor and material costs.

  12. 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.

  13. Big Bang Day: 5 Particles - 5. The Next Particle

    ScienceCinema

    None

    2016-07-12

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 5. The Next Particle The "sparticle" - a super symmetric partner to all the known particles could be the answer to uniting all the known particles and their interactions under one grand theoretical pattern of activity. But how do researchers know where to look for such phenomena and how do they know if they find them? Simon Singh reviews the next particle that physicists would like to find if the current particle theories are to ring true.

  14. Big Bang Day: 5 Particles - 5. The Next Particle

    SciTech Connect

    2009-10-08

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 5. The Next Particle The "sparticle" - a super symmetric partner to all the known particles could be the answer to uniting all the known particles and their interactions under one grand theoretical pattern of activity. But how do researchers know where to look for such phenomena and how do they know if they find them? Simon Singh reviews the next particle that physicists would like to find if the current particle theories are to ring true.

  15. International exploration by independent

    SciTech Connect

    Bertragne, R.G.

    1992-04-01

    Recent industry trends indicate that the smaller U.S. independents are looking at foreign exploration opportunities as one of the alternatives for growth in the new age of exploration. Foreign finding costs per barrel usually are accepted to be substantially lower than domestic costs because of the large reserve potential of international plays. To get involved in overseas exploration, however, requires the explorationist to adapt to different cultural, financial, legal, operational, and political conditions. Generally, foreign exploration proceeds at a slower pace than domestic exploration because concessions are granted by a country's government, or are explored in partnership with a national oil company. First, the explorationist must prepare a mid- to long-term strategy, tailored to the goals and the financial capabilities of the company; next, is an ongoing evaluation of quality prospects in various sedimentary basins, and careful planning and conduct of the operations. To successfully explore overseas also requires the presence of a minimum number of explorationists and engineers thoroughly familiar with the various exploratory and operational aspects of foreign work. Ideally, these team members will have had a considerable amount of on-site experience in various countries and climates. Independents best suited for foreign expansion are those who have been financially successful in domestic exploration. When properly approached, foreign exploration is well within the reach of smaller U.S. independents, and presents essentially no greater risk than domestic exploration; however, the reward can be much larger and can catapult the company into the 'big leagues.'

  16. PARTICLES OF DIFFERENCE.

    SciTech Connect

    SCHWARTZ,S.E.

    2000-09-21

    It is no longer appropriate, if it ever was, to think of atmospheric aerosols as homogeneous spheres of uniform composition and size. Within the United States, and even more globally, not only the mass loading but also the composition, morphology, and size distribution of atmospheric aerosols are highly variable, as a function of location, and at a given location as a function of time. Particles of a given aerodynamic size may differ from one another, and even within individual particles material may be inhomogeneously distributed, as for example, carbon spherules imbedded in much larger sulfate particles. Some of the particulate matter is primary, that is, introduced into the atmosphere directly as particles, such as carbon particles in diesel exhaust. Some is secondary, that is, formed in the atmosphere by gas-to-particle conversion. Much of the material is inorganic, mainly sulfates and nitrates resulting mainly from energy-related emissions. Some of the material is carbonaceous, in part primary, in part secondary, and of this material some is anthropogenic and some biogenic. While the heterogeneity of atmospheric aerosols complicates the problem of understanding their loading and distribution, it may well be the key to its solution. By detailed examination of the materials comprising aerosols it is possible to infer the sources of these materials. It may be possible as well to identify specific health impairing agents. The heterogeneity of aerosol particles is thus the key to identifying their sources, to understanding the processes that govern their loading and properties, and to devising control strategies that are both effective and efficient. Future research must therefore take cognizance of differences among aerosol particles and use these differences to advantage.

  17. BRL Particle Sizing Interferometer

    DTIC Science & Technology

    1982-07-01

    and m" is the index of refraction. Thus, the same visibility function as for Class I particles still applies. However, the fringe period is scaled ...amplitudes of the probability density plot are relative. The largest amplitude is chosen to fit a convenient scale on the paper. The first column indicates...the numerical integration,it is difficult to discern or physically visualize the scaling laws which relate visibility to particle index-of-refraction

  18. PARTICLES OF DIFFERENCE.

    SciTech Connect

    SCHWARTZ,S.E.

    2000-09-21

    It is no longer appropriate, if it ever was, to think of atmospheric aerosols as homogeneous spheres of uniform composition and size. Within the United States, and even more globally, not only the mass loading but also the composition, morphology, and size distribution of atmospheric aerosols are highly variable, as a function of location, and at a given location as a function of time. Particles of a given aerodynamic size may differ from one another, and even within individual particles material may be inhomogeneously distributed, as for example, carbon spherules imbedded in much larger sulfate particles. Some of the particulate matter is primary, that is, introduced into the atmosphere directly as particles, such as carbon particles in diesel exhaust. Some is secondary, that is, formed in the atmosphere by gas-to-particle conversion. Much of the material is inorganic, mainly sulfates and nitrates resulting mainly from energy-related emissions. Some of the material is carbonaceous, in part primary, in part secondary, and of this material some is anthropogenic and some biogenic. While the heterogeneity of atmospheric aerosols complicates the problem of understanding their loading and distribution, it may well be the key to its solution. By detailed examination of the materials comprising aerosols it is possible to infer the sources of these materials. It may be possible as well to identify specific health impairing agents. The heterogeneity of aerosol particles is thus the key to identifying their sources, to understanding the processes that govern their loading and properties, and to devising control strategies that are both effective and efficient. Future research must therefore take cognizance of differences among aerosol particles and use these differences to advantage.

  19. The Least Particle Theory

    NASA Astrophysics Data System (ADS)

    Hartsock, Robert

    2011-10-01

    The Least Particle Theory states that the universe was cast as a great sea of energy. MaX Planck declared a quantum of energy to be the least value in the universe. We declare the quantum of energy to be the least particle in the universe. Stephen Hawking declared quantum mechanics to be of no value in todays gross mechanics. That's like saying the number 1 has no place in mathematics.

  20. Safe biodegradable fluorescent particles

    DOEpatents

    Martin, Sue I.; Fergenson, David P.; Srivastava, Abneesh; Bogan, Michael J.; Riot, Vincent J.; Frank, Matthias

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  1. ELEMENTARY PARTICLE INTERACTIONS

    SciTech Connect

    EFREMENKO, YURI; HANDLER, THOMAS; KAMYSHKOV, YURI; SIOPSIS, GEORGE; SPANIER, STEFAN

    2013-07-30

    The High-Energy Elementary Particle Interactions group at UT during the last three years worked on the following directions and projects: Collider-based Particle Physics; Neutrino Physics, particularly participation in “NOνA”, “Double Chooz”, and “KamLAND” neutrino experiments; and Theory, including Scattering amplitudes, Quark-gluon plasma; Holographic cosmology; Holographic superconductors; Charge density waves; Striped superconductors; and Holographic FFLO states.

  2. On Characterizing Particle Shape

    NASA Technical Reports Server (NTRS)

    Ennis, Bryan J.; Rickman, Douglas; Rollins, A. Brent; Ennis, Brandon

    2014-01-01

    It is well known that particle shape affects flow characteristics of granular materials, as well as a variety of other solids processing issues such as compaction, rheology, filtration and other two-phase flow problems. The impact of shape crosses many diverse and commercially important applications, including pharmaceuticals, civil engineering, metallurgy, health, and food processing. Two applications studied here include the dry solids flow of lunar simulants (e.g. JSC-1, NU-LHT-2M, OB-1), and the flow properties of wet concrete, including final compressive strength. A multi-dimensional generalized, engineering method to quantitatively characterize particle shapes has been developed, applicable to both single particle orientation and multi-particle assemblies. The two-dimension, three dimension inversion problem is also treated, and the application of these methods to DEM model particles will be discussed. In the case of lunar simulants, flow properties of six lunar simulants have been measured, and the impact of particle shape on flowability - as characterized by the shape method developed here -- is discussed, especially in the context of three simulants of similar size range. In the context of concrete processing, concrete construction is a major contributor to greenhouse gas production, of which the major contributor is cement binding loading. Any optimization in concrete rheology and packing that can reduce cement loading and improve strength loading can also reduce currently required construction safety factors. The characterization approach here is also demonstrated for the impact of rock aggregate shape on concrete slump rheology and dry compressive strength.

  3. Statistics of indistinguishable particles.

    PubMed

    Wittig, Curt

    2009-07-02

    The wave function of a system containing identical particles takes into account the relationship between a particle's intrinsic spin and its statistical property. Specifically, the exchange of two identical particles having odd-half-integer spin results in the wave function changing sign, whereas the exchange of two identical particles having integer spin is accompanied by no such sign change. This is embodied in a term (-1)(2s), which has the value +1 for integer s (bosons), and -1 for odd-half-integer s (fermions), where s is the particle spin. All of this is well-known. In the nonrelativistic limit, a detailed consideration of the exchange of two identical particles shows that exchange is accompanied by a 2pi reorientation that yields the (-1)(2s) term. The same bookkeeping is applicable to the relativistic case described by the proper orthochronous Lorentz group, because any proper orthochronous Lorentz transformation can be expressed as the product of spatial rotations and a boost along the direction of motion.

  4. Particle Accelerators Test Cosmological Theory.

    ERIC Educational Resources Information Center

    Schramm, David N.; Steigman, Gary

    1988-01-01

    Discusses the symbiotic relationship of cosmology and elementary-particle physics. Presents a brief overview of particle physics. Explains how cosmological considerations set limits on the number of types of elementary particles. (RT)

  5. Particle Accelerators Test Cosmological Theory.

    ERIC Educational Resources Information Center

    Schramm, David N.; Steigman, Gary

    1988-01-01

    Discusses the symbiotic relationship of cosmology and elementary-particle physics. Presents a brief overview of particle physics. Explains how cosmological considerations set limits on the number of types of elementary particles. (RT)

  6. Experimental investigation of suspended particles transport through porous media: particle and grain size effect.

    PubMed

    Liu, Quansheng; Cui, Xianze; Zhang, Chengyuan; Huang, Shibing

    2016-01-01

    Particle and grain size may influence the transportation and deposition characteristics of particles within pollutant transport and within granular filters that are typically used in wastewater treatment. We conducted two-dimensional sandbox experiments using quartz powder as the particles and quartz sand as the porous medium to study the response of transportation and deposition formation to changes in particle diameter (ds, with median diameter 18, 41, and 82 μm) and grain diameter (dp, with median diameter 0.36, 1.25, and 2.82 mm) considering a wide range of diameter ratios (ds/dp) from 0.0064 to 0.228. Particles were suspended in deionized water, and quartz sand was used as the porous medium, which was meticulously cleaned to minimize any physicochemical and impurities effects that could result in indeterminate results. After the experiments, the particle concentration of the effluent and particle mass per gram of dry sands were measured to explore changes in transportation and deposition characteristics under different conditions. In addition, a micro-analysis was conducted to better analyse the results on a mesoscopic scale. The experimental observation analyses indicate that different diameter ratios (ds/dp) may lead to different deposit formations. As ds/dp increased, the deposit formation changed from 'Random Deposition Type' to 'Gradient Deposition Type', and eventually became 'Inlet Deposition Type'.

  7. Quantum particle interacting with a metallic particle: Spectra from quantum Langevin theory

    NASA Astrophysics Data System (ADS)

    Loh, W. M. Edmund; Ooi, C. H. Raymond

    2017-01-01

    The effect of a nearby metallic particle on the quantum optical properties of a quantum particle in the four-level double Raman configuration is studied using the quantum Langevin approach. We obtain analytical expressions for the correlated quantum fields of Stokes and anti-Stokes photons emitted from the system and perform analysis on how the interparticle distance, the direction of observation or detection, the strengths of controllable laser fields, the presence of surface plasmon resonance, and the number density of the quantum particle affect the quantum spectra of the Stokes and anti-Stokes fields. We explore the physics behind the quantum-particle-metallic-nanoparticle interaction within the dipole approximation, that is, when the interparticle distance is much larger than the sizes of the particles. Our results show the dependence of the spectra on the interparticle distance in the form of oscillatory behavior with damping as the interparticle distance increases. At weaker laser fields the enhancement of quantum fields which manifests itself in the form of a Fano dip in the central peak of the spectra becomes significant. Also, the quantum-particle-metallic-nanoparticle coupling, which is affected by the size of the metallic nanoparticle and the number density of the quantum particle, changes the angular dependence of the spectra by breaking the angular rotational symmetry. In the presence of surface plasmon resonance the oscillatory dependence of the spectra on the interparticle distance and angles of observation becomes even stronger due to the plasmonic enhancement effect.

  8. The Coming Revolutions in Particle Physics

    NASA Astrophysics Data System (ADS)

    Quigg, Chris

    2006-12-01

    Wonderful opportunities await particle physics over the next decade, with new instruments and experiments poised to explore the frontiers of high energy, infinitesimal distances, and exquisite rarity. I will review the insights of the decade just past and show how they lead us to the brink of a new period of rapid and profound discovery. We expect answers to questions that speak to our understanding of the everyday world: why are there atoms? why chemistry? why stable structures? and even what makes life possible? We are probing the meaning of identity for the fundamental particles: what makes an electron an electron, a neutrino a neutrino, and a top quark a top quark? Important clues, including the remarkable neutrality of atoms, lead us to investigate the unity of the two main classes of matter, the quarks and leptons. Gravity and particle physics, long separate disciplines, are enjoying a stimulating reunion, and we are learning how to investigate—with experiments—new conceptions of spacetime. We look forward to the Large Hadron Collider at CERN to explore the a new and critical energy scale of one trillion electron volts. If we are inventive enough, we may be able to follow the LHC's rich menu with the physics opportunities offered by a linear electron-positron collider, a (muon storage ring) neutrino factory, and experiments that use natural sources. I expect a remarkable flowering of experimental particle physics, and of theoretical physics that engages with experiment.

  9. Optical force and torque on dipolar dual chiral particles

    NASA Astrophysics Data System (ADS)

    Rahimzadegan, A.; Fruhnert, M.; Alaee, R.; Fernandez-Corbaton, I.; Rockstuhl, C.

    2016-09-01

    On the one hand, electromagnetic dual particles preserve the helicity of light upon interaction. On the other hand, chiral particles respond differently to light of opposite helicity. These two properties on their own constitute a source of fascination. Their combined action, however, is less explored. Here, we study on analytical grounds the force and torque as well as the optical cross sections of dual chiral particles in the dipolar approximation exerted by a particular wave of well-defined helicity: A circularly polarized plane wave. We put emphasis on particles that possess a maximally electromagnetic chiral and hence dual response. Besides the analytical insights, we also investigate the exerted optical force and torque on a real particle using the example of a metallic helix that is designed to approach the maximal electromagnetic chirality condition. Various applications in the context of optical sorting but also nanorobotics can be foreseen considering the particles studied in this contribution.

  10. Particle dynamics near Kerr-MOG black hole

    NASA Astrophysics Data System (ADS)

    Sharif, M.; Shahzadi, Misbah

    2017-06-01

    This paper explores the dynamics of both neutral and charged particles orbiting near a rotating black hole in scalar-tensor-vector gravity. We study the conditions for the particle to escape at the innermost stable circular orbit. We investigate the stability of orbits through the effective potential and Lyapunov exponent in the presence of a magnetic field. The effective force acting on particle is also discussed. We also study the center of mass energy of particle collision near the horizon of this black hole. Finally, we compare our results with the particle motion around Schwarzschild, Kerr and Schwarzschild-MOG black holes. It is concluded that the external magnetic field, spin parameter and dimensionless parameter of the theory have strong effects on the particle dynamics in modified gravity.

  11. Colloidal suspensions of C-particles: Entanglement, percolation and microrheology

    NASA Astrophysics Data System (ADS)

    Hoell, Christian; Löwen, Hartmut

    2016-05-01

    We explore structural and dynamical behavior of concentrated colloidal suspensions made up by C-shape particles using Brownian dynamics computer simulations and theory. In particular, we focus on the entanglement process between nearby particles for almost closed C-shapes with a small opening angle. Depending on the opening angle and the particle concentration, there is a percolation transition for the cluster of entangled particles which shows the classical scaling characteristics. In a broad density range below the percolation threshold, we find a stretched exponential function for the dynamical decorrelation of the entanglement process. Finally, we study a setup typical in microrheology by dragging a single tagged particle with constant speed through the suspension. We measure the cluster connected to and dragged with this tagged particle. In agreement with a phenomenological theory, the size of the dragged cluster depends on the dragging direction and increases markedly with the dragging speed.

  12. Diffusion of micrometer-sized soft particles in confinement

    NASA Astrophysics Data System (ADS)

    Jordan, Benjamin; Aptowicz, Kevin

    We investigate the diffusion of micrometer sized poly(N-isopropylacrylamide) (PNIPAM) gel particles in confinement. The influence of confinement on the transport of small particles is becoming increasingly important for microfluidics and bio-fluidics. Analytical solutions to this problem are limited to very unique geometries or gross approximations. Computational methods have provided more insight into the problem as well as experimental investigations. However, most research has focused on the hard-sphere problem. In this work, we will explore the diffusion of soft particles in confinement. The dynamics of the particles confined between two parallel walls is captured with video-microscopy. In addition, we use a recently developed technique to measurement confinement of particles in-situ with a precision of 1%. This poster will present some preliminary results of how confinement affects the diffusion of these soft particles. We acknowledge support from Grant DMR-1206231.

  13. Four-way coupled simulations of small particles in turbulent channel flow: The effects of particle shape and Stokes number

    NASA Astrophysics Data System (ADS)

    Zhao, F.; George, W. K.; van Wachem, B. G. M.

    2015-08-01

    This paper investigates the effects of particle shape and Stokes number on the behaviour of non-spherical particles in turbulent channel flow. Although there are a number of studies concerning spherical particles in turbulent flows, most important applications occurring in process, energy, and pharmaceutical industries deal with non-spherical particles. The computation employs a unique and novel four-way coupling with the Lagrangian point-particle approach. The fluid phase at low Reynolds number (Reτ = 150) is modelled by direct numerical simulation, while particles are tracked individually. Inter-particle and particle-wall collisions are also taken into account. To explore the effects of particles on the flow turbulence, the statistics of the fluid flow such as the fluid velocity, the terms in the turbulence kinetic energy equation, the slip velocity between the two phases and velocity correlations are analysed considering ellipsoidal particles with different inertia and aspect ratio. The results of the simulations show that the turbulence is considerably attenuated, even in the very dilute regime. The reduction of the turbulence intensity is predominant near the turbulence kinetic energy peak in the near wall region, where particles preferentially accumulate. Moreover, the elongated shape of ellipsoids strengthens the turbulence attenuation. In simulations with ellipsoidal particles, the fluid-particle interactions strongly depend on the orientation of the ellipsoids. In the near wall region, ellipsoids tend to align predominantly within the streamwise (x) and wall-normal (y) planes and perpendicular to the span-wise direction, whereas no preferential orientation in the central region of the channel is observed. Important conclusions from this work include the effective viscosity of the flow is not affected, the direct dissipation by the particles is negligible, and the primary mechanism by which the particles affect the flow is by altering the turbulence

  14. Four-way coupled simulations of small particles in turbulent channel flow: The effects of particle shape and Stokes number

    SciTech Connect

    Zhao, F.; Wachem, B. G. M. van; George, W. K.

    2015-08-15

    This paper investigates the effects of particle shape and Stokes number on the behaviour of non-spherical particles in turbulent channel flow. Although there are a number of studies concerning spherical particles in turbulent flows, most important applications occurring in process, energy, and pharmaceutical industries deal with non-spherical particles. The computation employs a unique and novel four-way coupling with the Lagrangian point-particle approach. The fluid phase at low Reynolds number (Re{sub τ} = 150) is modelled by direct numerical simulation, while particles are tracked individually. Inter-particle and particle-wall collisions are also taken into account. To explore the effects of particles on the flow turbulence, the statistics of the fluid flow such as the fluid velocity, the terms in the turbulence kinetic energy equation, the slip velocity between the two phases and velocity correlations are analysed considering ellipsoidal particles with different inertia and aspect ratio. The results of the simulations show that the turbulence is considerably attenuated, even in the very dilute regime. The reduction of the turbulence intensity is predominant near the turbulence kinetic energy peak in the near wall region, where particles preferentially accumulate. Moreover, the elongated shape of ellipsoids strengthens the turbulence attenuation. In simulations with ellipsoidal particles, the fluid-particle interactions strongly depend on the orientation of the ellipsoids. In the near wall region, ellipsoids tend to align predominantly within the streamwise (x) and wall-normal (y) planes and perpendicular to the span-wise direction, whereas no preferential orientation in the central region of the channel is observed. Important conclusions from this work include the effective viscosity of the flow is not affected, the direct dissipation by the particles is negligible, and the primary mechanism by which the particles affect the flow is by altering the turbulence

  15. 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.

  16. Particle segregation during explosive dispersal of binary particle mixtures

    NASA Astrophysics Data System (ADS)

    Frost, David L.; Loiseau, Jason; Marr, Bradley J.; Goroshin, Samuel

    2017-01-01

    The explosive dispersal of a layer of solid particles surrounding a spherical high explosive charge generates a turbulent, multiphase flow. The shock-compacted particle layer typically fractures into discrete fragments which move radially outwards on ballistic trajectories. The fragments shed particles in their wakes forming jet-like structures. The tendency to form jets depends on the mass-ratio of the particles to explosive and the type of particles. Brittle or soft, ductile particles are more susceptible to forming jets during compaction and dispersal, whereas particles that are comprised of material with moderate hardness, high compressive strength and high toughness are much less prone to forming jets. Experiments have been carried out to determine the degree of particle segregation that occurs during the explosive dispersal of a uniform, binary mixture containing both "jetting" (silicon carbide) and "non-jetting" (steel) particles with various mass fractions of each particle type. During the dispersal of mixtures that contain predominantly non-jetting (steel) particles, the steel particles form a stable layer whereas the jetting (silicon carbide) particles rapidly segregate and form jets which are confined within the shell of steel particles. As the fraction of silicon carbide particles increases, the jet structures dominate the particle motion and the steel particles are entrained into the jet structures.

  17. Tortuosity of porous particles.

    PubMed

    Barrande, M; Bouchet, R; Denoyel, R

    2007-12-01

    Tortuosity is often used as an adjustable parameter in models of transfer properties through porous media. This parameter, not reducible to classical measured microstructural parameters like specific surface area, porosity, or pore size distribution, reflects the efficiency of percolation paths, which is linked to the topology of the material. The measurement of the effective conductivity of a bed of particles saturated with an electrolyte is a simple way to evaluate tortuosity. Nevertheless, it received only little attention because of the real difficulties in both getting reliable results and interpreting data. Notably, the discrimination between the contribution of interparticle and intraparticle porosities to the tortuosity is not resolved. To our knowledge, there is no model able to fit the experimental data of the tortuosity of a suspension, and a fortiori of a particle bed, in the whole porosity range. Only empirical expressions have been proposed, but they do not allow deriving intratortuosity of a porous particle. For a dilute system, Maxwell's equation predicts the effective conductivity of suspensions of spherical particles as a function of the bulk electrolyte conductivity and of particle conductivity. The intraparticle tortuosity can be derived from the particle conductivity obtained from the Maxwell equation applied to data at infinite dilution of particles. Then, by assuming that the Maxwell equation is a first-order approximation of the conductivity as a function of porosity, we propose an explicit relation of the tortuosity tau of a suspension of porous particles, obtained by conductivity measurement, as tau = tau(epsilon, epsilon(p), tau(p)), where epsilon is the total porosity of the suspension, tau(p) is the intraparticle tortuosity, and epsilon(p) is the particle porosity. This relationship fits the experimental data in the whole porosity range and can be used to determine tau(p) from an experiment at only one porosity. Finally, the obtained

  18. The Effect of Particle Properties on Hot Particle Spot Fire Ignition

    NASA Astrophysics Data System (ADS)

    Zak, Casey David

    The ignition of natural combustible material by hot metal particles is an important fire ignition pathway by which wildland and wildland-urban-interface spot fires are started. There are numerous cases reported of wild fires started by clashing power-lines or from sparks generated by machines or engines. Similarly there are many cases reported of fires caused by grinding, welding and cutting sparks. Up to this point, research on hot particle spot fire ignition has largely focused on particle generation and transport. A small number of studies have examined what occurs after a hot particle contacts a natural fuel bed, but until recently the process remained poorly understood. This work describes an investigation of the effect of particle size, temperature and thermal properties on the ability of hot particles to cause flaming ignition of cellulosic fuel beds. Both experimental and theoretical approaches are used, with a focus on understanding the physics underlying the ignition process. For the experimental study, spheres of stainless steel, aluminum, brass and copper are heated in a tube furnace and dropped onto a powdered cellulose fuel bed; the occurrence of flaming ignition or lack thereof is visually observed and recorded. This procedure is repeated a large number of times for each metal type, varying particle diameter from 2 to 11 mm and particle temperature between 575 and 1100°C. The results of these experiments are statistically analyzed to find approximate ignition boundaries and identify boundary trends with respect to the particle parameters of interest. Schlieren images recorded during the ignition experiments are also used to more accurately describe the ignition process. Based on these images, a simple theoretical model of hot particle spot fire ignition is developed and used to explore the experimental trends further. The model under-predicts the minimum ignition temperatures required for small spheres, but agrees qualitatively with the experimental

  19. NASA Exploration Design Challenge

    NASA Image and Video Library

    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...

  20. 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)

  1. 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)

  2. Venus Exploration Power Technologies

    NASA Astrophysics Data System (ADS)

    Surampudi, R.; Bugga, K.; Grandidier, J.; Cutts, J. A.; Beauchamp, P. M.

    2017-02-01

    Venus with its severe temperatures and pressures presents formidable challenges for powering in situ exploration vehicles. This paper describes possible approaches for both power generation and energy storage.

  3. Technology Drives Exploration

    NASA Image and Video Library

    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 ...

  4. Optimal exploration systems

    NASA Astrophysics Data System (ADS)

    Klesh, Andrew T.

    This dissertation studies optimal exploration, defined as the collection of information about given objects of interest by a mobile agent (the explorer) using imperfect sensors. The key aspects of exploration are kinematics (which determine how the explorer moves in response to steering commands), energetics (which determine how much energy is consumed by motion and maneuvers), informatics (which determine the rate at which information is collected) and estimation (which determines the states of the objects). These aspects are coupled by the steering decisions of the explorer. We seek to improve exploration by finding trade-offs amongst these couplings and the components of exploration: the Mission, the Path and the Agent. A comprehensive model of exploration is presented that, on one hand, accounts for these couplings and on the other hand is simple enough to allow analysis. This model is utilized to pose and solve several exploration problems where an objective function is to be minimized. Specific functions to be considered are the mission duration and the total energy. These exploration problems are formulated as optimal control problems and necessary conditions for optimality are obtained in the form of two-point boundary value problems. An analysis of these problems reveals characteristics of optimal exploration paths. Several regimes are identified for the optimal paths including the Watchtower, Solar and Drag regime, and several non-dimensional parameters are derived that determine the appropriate regime of travel. The so-called Power Ratio is shown to predict the qualitative features of the optimal paths, provide a metric to evaluate an aircrafts design and determine an aircrafts capability for flying perpetually. Optimal exploration system drivers are identified that provide perspective as to the importance of these various regimes of flight. A bank-to-turn solar-powered aircraft flying at constant altitude on Mars is used as a specific platform for

  5. System for forming janus particles

    DOEpatents

    Hong, Liang [Midland, MI; Jiang, Shan [Champaign, IL; Granick, Steve [Champaign, IL

    2011-01-25

    The invention is a method of forming Janus particles, that includes forming an emulsion that contains initial particles, a first liquid, and a second liquid; solidifying the first liquid to form a solid that contains at least a portion of the initial particles on a surface of the solid; and treating the exposed particle sides with a first surface modifying agent, to form the Janus particles. Each of the initial particles on the surface has an exposed particle side and a blocked particle side.

  6. The Particle Puzzle

    NASA Image and Video Library

    This video explores the complexity of atmospheric aerosols: how they impact climate and how researchers study them. Glory's Aerosol Polarimetry Sensor and Cloud Camera will provide an unprecedented...

  7. 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.

  8. Proton: the particle.

    PubMed

    Suit, Herman

    2013-11-01

    The purpose of this article is to review briefly the nature of protons: creation at the Big Bang, abundance, physical characteristics, internal components, and life span. Several particle discoveries by proton as the experimental tool are considered. Protons play important roles in science, medicine, and industry. This article was prompted by my experience in the curative treatment of cancer patients by protons and my interest in the nature of protons as particles. The latter has been stimulated by many discussions with particle physicists and reading related books and journals. Protons in our universe number ≈10(80). Protons were created at 10(-6) -1 second after the Big Bang at ≈1.37 × 10(10) years beforethe present. Proton life span has been experimentally determined to be ≥10(34) years; that is, the age of the universe is 10(-24)th of the minimum life span of a proton. The abundance of the elements is hydrogen, ≈74%; helium, ≈24%; and heavier atoms, ≈2%. Accordingly, protons are the dominant baryonic subatomic particle in the universe because ≈87% are protons. They are in each atom in our universe and thus involved in virtually every activity of matter in the visible universe, including life on our planet. Protons were discovered in 1919. In 1968, they were determined to be composed of even smaller particles, principally quarks and gluons. Protons have been the experimental tool in the discoveries of quarks (charm, bottom, and top), bosons (W(+), W(-), Z(0), and Higgs), antiprotons, and antineutrons. Industrial applications of protons are numerous and important. Additionally, protons are well appreciated in medicine for their role in radiation oncology and in magnetic resonance imaging. Protons are the dominant baryonic subatomic particle in the visible universe, comprising ≈87% of the particle mass. They are present in each atom of our universe and thus a participant in every activity involving matter.

  9. Particles causing lung disease.

    PubMed Central

    Kilburn, K H

    1984-01-01

    The lung has a limited number of patterns of reaction to inhaled particles. The disease observed depends upon the location: conducting airways, terminal bronchioles and alveoli, and upon the nature of inflammation induced: acute, subacute or chronic. Many different agents cause narrowing of conducting airways (asthma) and some of these cause permanent distortion or obliteration of airways as well. Terminal bronchioles appear to be particularly susceptible to particles which cause goblet cell metaplasia, mucous plugging and ultimately peribronchiolar fibrosis. Cancer is the last outcome at the bronchial level and appears to depend upon continuous exposure to or retention of an agent in the airway and failure of the affected cells to be exfoliated which may be due to squamous metaplasia. Alveoli are populated by endothelial cells, Type I or pavement epithelial cells and metabolically active cuboidal Type II cells that produce the lungs specific surfactant, dipalmytol lecithin. Disturbances of surfactant lead to edema in distal lung while laryngeal edema due to anaphylaxis or fumes may produce asphyxia. Physical retention of indigestible particles or retention by immune memory responses may provoke hyaline membranes, stimulate alveolar lipoproteinosis and finally fibrosis. This later exuberant deposition of connective tissue has been best studied in the occupational pneumoconioses especially silicosis and asbestosis. In contrast emphysema a catabolic response, appears frequently to result from leakage or release of lysosomal proteases into the lung during processing of cigarette smoke particles. The insidious and probably most important human lung disease due to particles is bronchiolar obstruction and obliteration, producing progressive impairment of air flow. The responsible particle is the complex combination of poorly digestive lipids and complex carbohydrates with active chemicals which we call cigarette smoke. More research is needed to perfect, correct and

  10. Alpha-particle microdosimetry.

    PubMed

    Chouin, Nicolas; Bardies, Manuel

    2011-07-01

    With the increasing availability of alpha emitters, targeted α-particle therapy has emerged as a solution of choice to treat haematological cancers and micrometastatic and minimal residual diseases. Alpha-particles are highly cytotoxic because of their high linear energy transfer (LET) and have a short range of a few cell diameters in tissue, assuring good treatment specificity. These radiologic features make conventional dosimetry less relevant for that context. Stochastic variations in the energy deposited in cell nuclei are important because of the microscopic target size, low number of α- particle traversals, and variation in LET along the α-particle track. Microdosimetry provides a conceptual framework that aims at a systematic analysis of the stochastic distribution of energy deposits in irradiated matter. The different quantities of microdosimetry and the different methods of microdosimetric calculations were described in the early eighties. Since then, numerous models have been published through the years and applied to analyse experimental data or to model realistic therapeutic situations. Major results have been an accurate description of the high toxicity of α-particles, and the description of the predominant effect of activity distribution at the cellular scale on toxicity or efficacy of potential targeted α-particle therapies. This last factor represents a major limitation to the use of microdosimetry in vivo because determination of the source - target distribution is complicated. The future contributions of microdosimetry in targeted α-particle therapy research will certainly depend on the ability to develop high-resolution detectors and on the implementation of pharmaco-kinetic models at the tumour microenvironment scale.

  11. Proton: The Particle

    SciTech Connect

    Suit, Herman

    2013-11-01

    The purpose of this article is to review briefly the nature of protons: creation at the Big Bang, abundance, physical characteristics, internal components, and life span. Several particle discoveries by proton as the experimental tool are considered. Protons play important roles in science, medicine, and industry. This article was prompted by my experience in the curative treatment of cancer patients by protons and my interest in the nature of protons as particles. The latter has been stimulated by many discussions with particle physicists and reading related books and journals. Protons in our universe number ≈10{sup 80}. Protons were created at 10{sup −6} –1 second after the Big Bang at ≈1.37 × 10{sup 10} years beforethe present. Proton life span has been experimentally determined to be ≥10{sup 34} years; that is, the age of the universe is 10{sup −24}th of the minimum life span of a proton. The abundance of the elements is hydrogen, ≈74%; helium, ≈24%; and heavier atoms, ≈2%. Accordingly, protons are the dominant baryonic subatomic particle in the universe because ≈87% are protons. They are in each atom in our universe and thus involved in virtually every activity of matter in the visible universe, including life on our planet. Protons were discovered in 1919. In 1968, they were determined to be composed of even smaller particles, principally quarks and gluons. Protons have been the experimental tool in the discoveries of quarks (charm, bottom, and top), bosons (W{sup +}, W{sup −}, Z{sup 0}, and Higgs), antiprotons, and antineutrons. Industrial applications of protons are numerous and important. Additionally, protons are well appreciated in medicine for their role in radiation oncology and in magnetic resonance imaging. Protons are the dominant baryonic subatomic particle in the visible universe, comprising ≈87% of the particle mass. They are present in each atom of our universe and thus a participant in every activity involving matter.

  12. Particle Filter with Nudging in Soil Hydrology

    NASA Astrophysics Data System (ADS)

    Berg, D.; Bauser, H. H.; Roth, K.

    2015-12-01

    The Ensemble Kalman Filter (EnKF) is widely employed in soil hydrology but is challenged by the characteristics of the processes there. These are highly nonlinear and state variables occasionally show sharp fronts and discontinuities across layer boundaries. This leads to sometimes strongly non-gaussian probability distributions, which is at odds with the EnFK's basic assumption. Therefore, we explore particle filters, which are able to handle such situations. However, standard particle filters with resampling suffer from the curse of dimensionality. They are thus not applicable to high-dimensional systems as they are encountered with soil water dynamics. A particle filter that may be able to lift this curse was proposed by van Leeuwen (2010). He introduced a nudging term based on the freedom of the proposal density. This particle filter has been applied in oceanography and showed promising results. While oceanography focuses on state estimation, soil hydrology in addition aims at parameter estimation. Therefore, we test the applicability of this filter for a one-dimensional test case, where we estimate states and parameters simultaneously. We generate synthetic data that correspond to water content measurements as they would be available from time domain reflectometry (TDR) probes. The results are compared with the true parameters and water contents. Finally, the performance of this filter (with different nudging terms) is compared with an EnKF and a particle filter without nudging.

  13. A relationship between maximum packing of particles and particle size

    NASA Technical Reports Server (NTRS)

    Fedors, R. F.

    1979-01-01

    Experimental data indicate that the volume fraction of particles in a packed bed (i.e. maximum packing) depends on particle size. One explanation for this is based on the idea that particle adhesion is the primary factor. In this paper, however, it is shown that entrainment and immobilization of liquid by the particles can also account for the facts.

  14. Review of Particle Physics

    NASA Astrophysics Data System (ADS)

    Olive, K. A.; Particle Data Group; et al.

    2016-10-01

    The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation. The complete Review is published online in a journal and on the website of the Particle Data Group (http://pdg.lbl.gov). The printed PDG Book contains the Summary Tables and all review articles but no longer includes the detailed tables from the Particle Listings. A Booklet with the Summary Tables and abbreviated versions of some of the review articles is also available. Contents Abstract, Contributors, Highlights and Table of ContentsAcrobat PDF (150 KB) IntroductionAcrobat PDF (456 KB) Particle Physics Summary Tables Gauge and Higgs bosonsAcrobat PDF (155 KB) LeptonsAcrobat PDF (134 KB) QuarksAcrobat PDF (84 KB) MesonsAcrobat PDF (871 KB) BaryonsAcrobat PDF (300 KB) Searches (Supersymmetry, Compositeness, etc.)Acrobat PDF (91 KB) Tests of conservation lawsAcrobat PDF (330 KB) Reviews, Tables, and Plots Detailed contents for this sectionAcrobat PDF (37 KB) Constants, Units, Atomic and Nuclear PropertiesAcrobat PDF (278 KB) Standard Model and Related TopicsAcrobat PDF (7.3 MB) Astrophysics and CosmologyAcrobat PDF (2.7 MB) Experimental Methods and CollidersAcrobat PDF (3.8 MB) Mathematical Tools or Statistics, Monte Carlo, Group

  15. Review of Particle Physics

    NASA Astrophysics Data System (ADS)

    Patrignani, C.; Particle Data Group

    2016-10-01

    The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation. The complete Review is published online in a journal and on the website of the Particle Data Group (http://pdg.lbl.gov). The printed PDG Book contains the Summary Tables and all review articles but no longer includes the detailed tables from the Particle Listings. A Booklet with the Summary Tables and abbreviated versions of some of the review articles is also available. Contents Abstract, Contributors, Highlights and Table of ContentsAcrobat PDF (150 KB) IntroductionAcrobat PDF (456 KB) Particle Physics Summary Tables Gauge and Higgs bosonsAcrobat PDF (155 KB) LeptonsAcrobat PDF (134 KB) QuarksAcrobat PDF (84 KB) MesonsAcrobat PDF (871 KB) BaryonsAcrobat PDF (300 KB) Searches (Supersymmetry, Compositeness, etc.)Acrobat PDF (91 KB) Tests of conservation lawsAcrobat PDF (330 KB) Reviews, Tables, and Plots Detailed contents for this sectionAcrobat PDF (37 KB) Constants, Units, Atomic and Nuclear PropertiesAcrobat PDF (278 KB) Standard Model and Related TopicsAcrobat PDF (7.3 MB) Astrophysics and CosmologyAcrobat PDF (2.7 MB) Experimental Methods and CollidersAcrobat PDF (3.8 MB) Mathematical Tools or Statistics, Monte Carlo, Group

  16. 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

  17. Particle physics and cosmology

    SciTech Connect

    Kolb, E.W.

    1986-10-01

    This series of lectures is about the role of particle physics in physical processes that occurred in the very early stages of the bug gang. Of particular interest is the role of particle physics in determining the evolution of the early Universe, and the effect of particle physics on the present structure of the Universe. The use of the big bang as a laboratory for placing limits on new particle physics theories will also be discussed. Section 1 reviews the standard cosmology, including primordial nucleosynthesis. Section 2 reviews the decoupling of weakly interacting particles in the early Universe, and discusses neutrino cosmology and the resulting limits that may be placed on the mass and lifetime of massive neutrinos. Section 3 discusses the evolution of the vacuum through phase transitions in the early Universe and the formation of topological defects in the transitions. Section 4 covers recent work on the generation of the baryon asymmetry by baryon-number violating reactions in Grand Unified Theories, and mentions some recent work on baryon number violation effects at the electroweak transition. Section 5 is devoted to theories of cosmic inflation. Finally, Section 6 is a discussion of the role of extra spatial dimensions in the evolution of the early Universe. 78 refs., 32 figs., 6 tabs.

  18. Cosmology and Particle Physics

    NASA Astrophysics Data System (ADS)

    Steigman, G.

    1982-01-01

    The cosmic connections between physics on the very largest and very smallest scales are reviewed with an emphasis on the symbiotic relation between elementary particle physics and cosmology. After a review of the early Universe as a cosmic accelerator, various cosmological and astrophysical constraints on models of particle physics are outlined. To illustrate this approach to particle physics via cosmology, reference is made to several areas of current research: baryon non-conservation and baryon asymmetry; free quarks, heavy hadrons and other exotic relics; primordial nucleosynthesis and neutrino masses. In the last few years we have witnessed the birth and growth to healthy adolescence of a new collaboration between astrophysicists and particle physicists. The most notable success of this cooperative effort has been to provide the framework for understanding, within the context of GUTs and the hot big-bang cosmology, the universal baryon asymmetry. The most exciting new predictions this effort has spawned are that exotic relics may exist in detectable abundances. In particular, we may live in a neutrino-dominated Universe. In the next few years, accummulating laboratory data (for example proton decay, neutrino masses and oscillations) coupled with theoritical work in particle physics and cosmology will ensure the growth to maturity of this joint effort.

  19. Energetic Particles Investigation (EPI)

    NASA Astrophysics Data System (ADS)

    Fischer, H. M.; Mihalov, J. D.; Lanzerotti, L. J.; Wibberenz, G.; Rinnert, K.; Gliem, F. O.; Bach, J.

    1992-05-01

    The EPI instrument operates during the pre-entry phase of the Galileo Probe. The main objective is the study of the energetic particle population in the inner Jovian magnetosphere and in the upper atmosphere. This will be achieved through omnidirectional measurements of electrons, protons, alpha-particles and heavy ions (Z greater than 2) and recording intensity profiles with a spatial resolution of about 0.02 Jupiter radii. Sectored data will also be obtained for electrons, protons, and alpha-particles to determine directional anisotropies and particle pitch angle distributions. The detector assembly is a two-element telescope using totally depleted circular silicon surface-barrier detectors surrounded by cylindrical tungsten shielding. The lower energy threshold of the particle species investigated during the Probe's pre-entry phase is determined by the material thickness of the Probe's rear heat shield which is required for heat protection of the scientific payload during entry into the Jovian atmosphere. The EPI instrument is combined with the Lightning and Radio Emission Detector and both instruments share one interface of the Probe's power, command, and data unit.

  20. RESONATOR PARTICLE SEPARATOR

    DOEpatents

    Blewett, J.P.

    1962-01-01

    A wave guide resonator structure is described for use in separating particles of equal momentum but differing in mass and having energies exceeding one billion electron volts. The particles are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high-energy accelerator. In this wave guide construction, the particles undergo preferential deflection as a result of the presence of an electric field. The boundary conditions established in the resonator are such as to eliminate an interfering magnetic component, and to otherwise phase the electric field to obtain a traveling wave such as one which moves at the same speed as the unwanted particle. The latter undergoes continuous deflection over the whole length of the device and is, therefore, eliminated while the wanted particle is deflected in opposite directions over the length of the resonator and is thus able to enter an exit aperture. (AEC)

  1. Large Particle Titanate Sorbents

    SciTech Connect

    Taylor-Pashow, K.

    2015-10-08

    This research project was aimed at developing a synthesis technique for producing large particle size monosodium titanate (MST) to benefit high level waste (HLW) processing at the Savannah River Site (SRS). Two applications were targeted, first increasing the size of the powdered MST used in batch contact processing to improve the filtration performance of the material, and second preparing a form of MST suitable for deployment in a column configuration. Increasing the particle size should lead to improvements in filtration flux, and decreased frequency of filter cleaning leading to improved throughput. Deployment of MST in a column configuration would allow for movement from a batch process to a more continuous process. Modifications to the typical MST synthesis led to an increase in the average particle size. Filtration testing on dead-end filters showed improved filtration rates with the larger particle material; however, no improvement in filtration rate was realized on a crossflow filter. In order to produce materials suitable for column deployment several approaches were examined. First, attempts were made to coat zirconium oxide microspheres (196 µm) with a layer of MST. This proved largely unsuccessful. An alternate approach was then taken synthesizing a porous monolith of MST which could be used as a column. Several parameters were tested, and conditions were found that were able to produce a continuous structure versus an agglomeration of particles. This monolith material showed Sr uptake comparable to that of previously evaluated samples of engineered MST in batch contact testing.

  2. DMSwarm: Particles in PETSc

    NASA Astrophysics Data System (ADS)

    May, Dave A.; Knepley, Matthew G.

    2017-04-01

    Whilst specific details of particle methods are as diverse as the applications in which they are utilized within, such methods have a number of common requirements. Specifically these entail: the need to attach data (or fields) to each point; support for the advection of points within some domain; dynamic insertion and deletion of points; collection type operations to gather nearby points; and methods to interpolate and restrict data back and forth between a set of points and a background mesh. Despite the commonality of these requirements, to date, few computational libraries provide high level support for particle methods in either a sequential, or parallel (MPI) computing environment. In this presentation, we describe the recently introduced implementation DMSwarm within the Portable, Extensible Toolkit for Scientific computing (PETSc) which provides a fully parallel solution for pure particle methods (e.g. DEM, SPH, EFG) and for particle-mesh methods (e.g. PIC, FLIP, MPM, GIMP). Particle-In-Cell (PIC) methods with geodynamic simulation tools are ubiquitous. To illustrate the functionality provided by DMSwarm, we present results from viscous flow calculations using a finite element PIC method applied to study Rayleigh-Taylor instabilities using both structured and unstructured meshes. Our results are derived from standard examples provided with the PETSc source distribution and serve as an entry-point for new users to learn how to incorporate DMSwarm into their geodynamic software.

  3. Lorentz force particle analyzer

    NASA Astrophysics Data System (ADS)

    Wang, Xiaodong; Thess, André; Moreau, René; Tan, Yanqing; Dai, Shangjun; Tao, Zhen; Yang, Wenzhi; Wang, Bo

    2016-07-01

    A new contactless technique is presented for the detection of micron-sized insulating particles in the flow of an electrically conducting fluid. A transverse magnetic field brakes this flow and tends to become entrained in the flow direction by a Lorentz force, whose reaction force on the magnetic-field-generating system can be measured. The presence of insulating particles suspended in the fluid produce changes in this Lorentz force, generating pulses in it; these pulses enable the particles to be counted and sized. A two-dimensional numerical model that employs a moving mesh method demonstrates the measurement principle when such a particle is present. Two prototypes and a three-dimensional numerical model are used to demonstrate the feasibility of a Lorentz force particle analyzer (LFPA). The findings of this study conclude that such an LFPA, which offers contactless and on-line quantitative measurements, can be applied to an extensive range of applications. These applications include measurements of the cleanliness of high-temperature and aggressive molten metal, such as aluminum and steel alloys, and the clean manufacturing of semiconductors.

  4. 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.

  5. Composite Technology for Exploration

    NASA Technical Reports Server (NTRS)

    Fikes, John

    2017-01-01

    The CTE (Composite Technology for Exploration) Project will develop and demonstrate critical composites technologies with a focus on joints that utilize NASA expertise and capabilities. The project will advance composite technologies providing lightweight structures to support future NASA exploration missions. The CTE project will demonstrate weight-saving, performance-enhancing bonded joint technology for Space Launch System (SLS)-scale composite hardware.

  6. We Are the Explorers

    NASA Image and Video Library

    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...

  7. 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…

  8. 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.

  9. 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.

  10. Venus Exploration to 2050

    NASA Astrophysics Data System (ADS)

    Cutts, J. A.; Grimm, R. E.; Gilmore, M.

    2017-02-01

    Venus should be an Earth-like planet due to its similar size and position in the solar system, but it has developed very differently. The Venus Exploration Assessment Group (VEXAG) has formulated long-range plans to explore our puzzling sister planet.

  11. 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…

  12. Big Bang Day: 5 Particles - 3. The Anti-particle

    ScienceCinema

    None

    2016-07-12

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 3. The Anti-particle. It appears to be the stuff of science fiction. Associated with every elementary particle is an antiparticle which has the same mass and opposite charge. Should the two meet and combine, the result is annihilation - and a flash of light. Thanks to mysterious processes that occurred after the Big Bang there are a vastly greater number of particles than anti-particles. So how could their elusive existence be proved? At CERN particle physicists are crashing together subatomic particles at incredibly high speeds to create antimatter, which they hope will finally reveal what happened at the precise moment of the Big Bang to create the repertoire of elementary particles and antiparticles in existence today.

  13. Big Bang Day: 5 Particles - 3. The Anti-particle

    SciTech Connect

    2009-10-07

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 3. The Anti-particle. It appears to be the stuff of science fiction. Associated with every elementary particle is an antiparticle which has the same mass and opposite charge. Should the two meet and combine, the result is annihilation - and a flash of light. Thanks to mysterious processes that occurred after the Big Bang there are a vastly greater number of particles than anti-particles. So how could their elusive existence be proved? At CERN particle physicists are crashing together subatomic particles at incredibly high speeds to create antimatter, which they hope will finally reveal what happened at the precise moment of the Big Bang to create the repertoire of elementary particles and antiparticles in existence today.

  14. 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.

  15. Quantum electrodynamics analysis of optical binding in counterpropagating beams and effect of particle size.

    PubMed

    Rodriguez, Justo

    2008-10-01

    A general expression for optical binding energy between particles of any size, in counterpropagating beams with and without interference, is derived using quantum electrodynamics. The effect of particle size on the optically induced interparticle energy surface, which has been the subject of recent research, is explored. Significant changes in this surface when particle size approaches the wavelength of the optical field are revealed. Finally, optically induced particle arrays that may be fabricated with these potentials are briefly discussed.

  16. SEDS MIL-STD-1773 fiber optic data bus: Proton irradiation test results and spaceflight SEU data

    SciTech Connect

    LaBel, K.A.; Stassinopoulos, E.G.; Miller, J.T. ); Marshall, P. ); Dale, C. ); Crabtree, C.M. ); Gates, M.M. )

    1993-12-01

    The Small Explorer Data System (SEDS) was launched in July of 1992 as part of the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX) mission. The SEDS utilizes NASA's first MIL-STD-1773 Fiber Optic Multiplexed Data Bus (or 1773 bus) to communicate with other spacecraft subsystems in the space environment. The 1773 bus is the fiber optic version of the MIL-STD-1553 Data Bus, a electronic wire bus used in many avionics applications. The authors present proton test and space flight single event effect data for NASA's first fiber optic data bus. Bit error rate predictions based on a new proton direct ionization model agree well with flight data for proton belt and solar flare effects.

  17. Charged particle accelerator grating

    DOEpatents

    Palmer, R.B.

    1985-09-09

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams onto the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  18. Carbon-particle generator

    DOEpatents

    Hunt, A.J.

    1982-09-29

    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.

  19. Precision wood particle feedstocks

    DOEpatents

    Dooley, James H; Lanning, David N

    2013-07-30

    Wood particles having fibers aligned in a grain, wherein: the wood particles are characterized by a length dimension (L) aligned substantially parallel to the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L; the L.times.H dimensions define two side surfaces characterized by substantially intact longitudinally arrayed fibers; the W.times.H dimensions define two cross-grain end surfaces characterized individually as aligned either normal to the grain or oblique to the grain; the L.times.W dimensions define two substantially parallel top and bottom surfaces; and, a majority of the W.times.H surfaces in the mixture of wood particles have end checking.

  20. Particle fuel bed tests

    SciTech Connect

    Horn, F.L.; Powell, J.R.; Savino, J.M.

    1985-01-01

    Gas-cooled reactors, using packed beds of small diameter coated fuel particles have been proposed for compact, high-power systems. The particulate fuel used in the tests was 800 microns in diameter, consisting of a thoria kernel coated with 200 microns of pyrocarbon. Typically, the bed of fuel particles was contained in a ceramic cylinder with porous metallic frits at each end. A dc voltage was applied to the metallic frits and the resulting electric current heated the bed. Heat was removed by passing coolant (helium or hydrogen) through the bed. Candidate frit materials, rhenium, nickel, zirconium carbide, and zirconium oxide were unaffected, while tungsten and tungsten-rhenium lost weight and strength. Zirconium-carbide particles were tested at 2000 K in H/sub 2/ for 12 hours with no visible reaction or weight loss.