Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Particle data analysis”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Interplanetary Magnetic Field Guiding Relativistic Particles

The origin and the propagation of relativistic solar particles (0.5 to few Ge V) in the interplanetary medium remains a debated topic. These relativistic particles, detected at the Earth by neutron monitors have been previously accelerated close to the Sun and are guided by the interplanetary magnetic field (IMF) lines, connecting the acceleration site and the Earth. Usually, the nominal Parker spiral is considered for ensuring the magnetic connection to the Earth. However, in most GLEs the IMF is highly disturbed, and the active regions associated to the GLEs are not always located close to the solar footprint of the nominal Parker spiral. A possible explanation is that relativistic particles are propagating in transient magnetic structures, such as Interplanetary Coronal Mass Ejections (ICMEs). In order to check this interpretation, we studied in detail the interplanetary medium where the particles propagate for 10 GLEs of the last solar cycle. Using the magnetic field and the plasma parameter measurements (ACE/MAG and ACE/SWEPAM), we found widely different IMF configurations. In an independent approach we develop and apply an improved method of the velocity dispersion analysis to energetic protons measured by SoHO/ERNE. We determined the effective path length and the solar release time of protons from these data and also combined them with the neutron monitor data. We found that in most of the GLEs, protons propagate in transient magnetic structures. Moreover, the comparison between the interplanetary magnetic structure and the interplanetary length suggest that the timing of particle arrival at Earth is dominantly determined by the type of IMF in which high energetic particles are propagating. Finally we find that these energetic protons are not significantly scattered during their transport to Earth.

Masson, S.↗
NASA NTRS1988

Complete positive ion, electron, and ram negative ion measurements near Comet Halley (COPERNIC) plasma experiment for the European Giotto Mission

Participation of U.S. scientists on the COPERNIC (COmplete Positive ions, Electrons and Ram Negative Ion measurements near Comet Halley) plasma experiment on the Giotto mission is described. The experiment consisted of two detectors: the EESA (electron electrostatic analyzer) which provided three-dimensional measurements of the distribution of electrons from 10 eV to 30 keV, and the PICCA (positive ion cluster composition analyzer) which provided mass analysis of positively charged cold cometary ions from mass 10 to 210 amu. In addition, a small 3 deg wide sector of the EESA looking in the ram direction was devoted to the detection of negatively charged cold cometary ions. Both detectors operated perfectly up to near closest approach (approx. 600 km) to Halley, but impacts of dust particles and neutral gas on the spacecraft contaminated parts of the data during the last few minutes. Although no flight hardware was fabricated in the U.S., The U.S. made very significant contributions to the hardware design, ground support equipment (GSE) design and fabrication, and flight and data reduction software required for the experiment, and also participated fully in the data reduction and analysis, and theoretical modeling and interpretation. Cometary data analysis is presented.

Lin, Robert P.↗
NASA NTRS2016

Using CubeSats to Monitor Debris Flux

Recent updates to NASA's Orbital Debris Engineering Model (ORDEM 3.0) include a population of small particles (1-2 mm in size) composed of high-density materials (e.g., steel) that drive much of the predicted risk for satellites in the 700-1000 km altitude regime. This modeled population was based on the analysis of returned surfaces of the Shuttle, which flew below 600 km altitude. The cessation of Shuttle missions, plus the lack of in situ data above 600 km means that a data source is being sought to either confirm or modify this high-density population. One possible data source would be a database of anomalous sporadic changes in spacecraft orbit/orientation that might be due to momentum transfer from small particles too small to seriously damage the spacecraft. Because the momentum imparted from an impact would be tiny, it would most likely show up in the orbital behavior of cubesats and other small satellites. While such small satellites were few in number, this was not a particularly attractive option, but now with the proliferation of cubesats in multiple orbit planes and altitudes, the possible collecting area has increased significantly. This presentation will discuss the physics of momentum-transferring impacts from hypervelocity collisions, and make predictions about rates, directions, and locations of such impacts. In addition, it will include recommendations for satellite users on what kind of data might be worth archiving and investigating.

Matney, Mark↗
NASA NTRS2005

Lunar and Planetary Science XXXVI, Part 13

Contents include the following: A Fast, Non-Destructive Method for Classifying Ordinary Chondrite Falls Using Density and Magnetic Susceptibility. An Update on Results from the Magnetic Properties Experiments on the Mars Exploration Rovers, Spirit and Opportunity. Measurement Protocols for In Situ Analysis of Organic Compounds at Mars and Comets. Piping Structures on Earth and Possibly Mars: Astrobiological Implications. Uranium and Lead in the Early Planetary Core Formation: New Insights Given by High Pressure and Temperature Experiments. The Mast Cameras and Mars Descent Imager (MARDI) for the 2009 Mars Science Laboratory. MGS MOC: First Views of Mars at Sub-Meter Resolution from Orbit. Analysis of Candor Chasma Interior Layered Deposits from OMEGA/MEX Spectra. Analysis of Valley Networks on Valles Marineris Plateau Using HRSC/MEX Data. Solar Abundance of Elements from Neutron-Capture Cross Sections. Preliminary Evaluation of the Secondary Ion/Accelerator Mass Spectrometer, MegaSIMS. Equilibrium Landforms in the Dry Valleys of Antarctica: Implications for Landscape Evolution and Climate Change on Mars. Continued Study of Ba Isotopic Compositions of Presolar Silicon Carbide Grains from Supernovae. Paleoenviromental Evolution of the Holden-Uzboi Area. Stability of Magnesium Sulfate Minerals in Martian Environments. Tungsten Isotopic Constraints on the Formation and Evolution of Iron Meteorite Parent Bodies. Migration of Dust Particles and Volatiles Delivery to the Inner Planets. On the Sitting of Trapped Noble Gases in Insoluble Organic Matter of Primitive Meteorites. Trapping of Xenon Upon Evaporation-Condensation of Organic Matter Under UV Irradiation: Isotopic Fractionation and Electron Paramagnetic Resonance Analysis. Stability of Water on Mars. A Didactic Activity. Analysis of Coronae in the Parga Chasma Region, Venus. Photometric and Compositional Surface Properties of the Gusev Crater Region, Mars, as Derived from Multi-Angle, Multi-Spectral Investigation of Mars Express HRSC Data. Mapping Compositional Diversity on Mars: Spatial Distribution and Geological Implications. A New Simulation Chamber for Studying Planetary Environments. Folded Structure in Terra Sirenum. Mars. Nitrogen-Noble Gas Static Mass Spectrometry of Genesis Collector Materials. Neon Isotope Heterogeneity in the Terrestrial Mantle: Implication for the Acquisition of Volatile Elements in Terrestrial Planets. The Cosmic Clock, the Cycle of Terrestrial Mass Extinctions.

Source record↗
NASA NTRS2015

ANTARES Constrains a Blazar Origin of Two IceCube PeV Neutrino Events

Context. The source(s) of the neutrino excess reported by the IceCube Collaboration is unknown. The TANAMI Collaboration recently reported on the multiwavelength emission of six bright, variable blazars which are positionally coincident with two of the most energetic IceCube events. Objects like these are prime candidates to be the source of the highest-energy cosmic rays, and thus of associated neutrino emission. Aims. We present an analysis of neutrino emission from the six blazars using observations with the ANTARES neutrino telescope. Methods. The standard methods of the ANTARES candidate list search are applied to six years of data to search for an excess of muons - and hence their neutrino progenitors - from the directions of the six blazars described by the TANAMI Collaboration, and which are possibly associated with two IceCube events. Monte Carlo simulations of the detector response to both signal and background particle fluxes are used to estimate the sensitivity of this analysis for di erent possible source neutrino spectra. A maximum-likelihood approach, using the reconstructed energies and arrival directions of through-going muons, is used to identify events with properties consistent with a blazar origin. Results. Both blazars predicted to be the most neutrino-bright in the TANAMI sample (1653-329 and 1714-336) have a signal flux fitted by the likelihood analysis corresponding to approximately one event. This observation is consistent with the blazar-origin hypothesis of the IceCube event IC 14 for a broad range of blazar spectra, although an atmospheric origin cannot be excluded. No ANTARES events are observed from any of the other four blazars, including the three associated with IceCube event IC20. This excludes at a 90% confidence level the possibility that this event was produced by these blazars unless the neutrino spectrum is flatter than -2.4.

general↗
NASA NTRS1972

Charged particle and magnetic field research in space

Research completed and in progress is described, related publications and reports are listed, and abstracts of papers and talks on results of the research are given. The charged particle research centered on OGO-5 and OGO-6 electron spectrometer data, and theoretical radiation belt studies. Work on the ATS-1 magnetometer project included development of production data reduction programs, development of spectral analysis procedures, and scientific studies of ULF waves at synchronous orbit. The magnetic fields research also included work on the Mariner project and theoretical studies on the solar wind.

Source record↗
NASA NTRS1976

Observations of Mercury's magnetic field

Magnetic-field observations made during the third encounter of Mariner 10 with Mercury are discussed along with implications of an intrinsic field for the planetary interior. The data obtained confirm the presence of characteristic bow-shock, magnetosheath, and magnetosphere regions surrounding the planet and also indicate that Mercury occupies a much larger portion of its magnetosphere than does earth. Combined plasma, charged-particle, and magnetic-field data establish that the origin of the field is intrinsic to the planet rather than associated with an induction process due to solar-wind flow. Spherical harmonic analysis of the field data shows that the internal field of the planet is well described by a centered dipole with a moment of 5.0 by 10 to the 22nd power gauss-cu cm and oriented within 12 deg of the normal to the orbital plane in the same sense as earth. Surface intensities are deduced to be between about 300 and 800 gammas. It is concluded that an active dynamo is a more likely candidate than fossil magnetization for the origin of the field.

Ness, N. F.↗
NASA NTRS1984

Post-mission Viking data anaysis

Three Mars data analysis projects from the Viking Mars program were identified initially, and three more came into being as the work proceeded. All together, these six pertained to: (1) the veritical distribution of scattering particles in the Martian atmosphere at various locations in various seasons, (2) the physical parameters that define photometric properties of the Martian surface and atmosphere, (3) patterns of dust-cloud and global dust-storm development, (4) a direct comparison of near-simultaneous Viking and ground-based observations, (5) the annual formation and dissipation of polar frost caps, and (6) evidence concerning possible present-day volcanism or venting. A list of publications pertaining to the appropriate projects is included.

Baum, W. A.↗
NASA NTRS1986

Lead, platinum and other heavy elements in the primary cosmic radiation: HEAO-3 results

An observation of the abundances of cosmic-ray lead and platinum-group nuclei using data from the HEAO-3 Heavy Nuclei Experiment (HNE) which consisted of ion chambers mounted on both sides of a plastic Cherenkov counter (Binns et al., 1981) is reported. Further analysis with more stringent selections, inclusion of additional data, and a calibration at the LBL Bevalac, have allowed the determination of the abundance ratio of lead and the platinum group of elements for particles that had a cutoff rigidity R(c) 5 GV. The observed ratio for Pb/Pt is distinctly lower than that predicted by any of the standard models for cosmic ray sources. It is possible that the difference is not an indication that the cosmic ray source composition is greatly different from that of the solar system, but rather that there is less Pb in the solar system and in the r-process than is assumed in the standard models.

Waddington, C. J.↗
NASA NTRS1995

A study of the radiation environment on board the space shuttle flight STS-57

A joint NASA-Russian study of the radiation environment inside a SPACEHAB 2 locker on space shuttle flight STS-57 was conducted. The shuttle flew in a nearly circular orbit of 28.5 deg inclination and 462 km altitude. The locker carried a charged particle spectrometer, a tissue equivalent proportional counter (TEPC), and two area passive detectors consisting of combined NASA plastic nuclear track detectors (PNTD's) and thermoluminescent detectors (TLD's), and Russian nuclear emulsions, PNTD's, and TLD's. All the detector systems were shielded by the same shuttle mass distribution. This makes possible a direct comparison of the various dose measurement techniques. In addition, measurements of the neutron energy spectrum were made using the proton recoil technique. The results show good agreement between the integral LET spectrum of the combined galactic and trapped particles using the tissue equivalent proportional counter and track detectors between about 15 keV/micron and 200 keV/micron. The LET spectrum determined from nuclear emulsions was systematically lower by about 50%, possibly due to emulsion fading. The results show that the TEPC measured an absorbed dose 20% higher than TLD's, due primarily to an increased TEPC response to neutrons and a low sensitivity of TLD's to high LET particles under normal processing techniques. There is a significant flux of high energy neutrons that is currently not taken into consideration in dose equivalent calculations. The results of the analysis of the spectrometer data will be reported separately.

Badhwar, G. D.↗
NASA NTRS2005

NASA Ames Arc Jets and Range, Capabilities for Planetary Entry

NASA is pursuing innovative technologies and concepts as part of America's Vision for Space Exploration. The rapidly emerging field of nanotechnology has led to new concepts for multipurpose shields to prevent catastrophic loss of vehicles and crew against the triple threats of aeroheating during atmospheric entry, radiation (Solar and galactic cosmic rays) and Micrometorid/Orbital Debris (MMOD) strikes. One proposed concept is the Thermal Radiation Impact Protection System (TRIPS) using carbon nanotubes, hydrogenated carbon nanotubes, and ceramic coatings as a multi-use TPS. The Thermophysics Facilities Branch of the Space Technology Division at NASA Ames Research Center provides testing services for the development and validation of the present and future concepts being developed by NASA and national and International research firms. The Branch operates two key facilities - the Range Complex and the Arc Jets. The Ranges include both the Ames Vertical Gun Range (AVGR) and the Hypervelocity Free Flight (HFF) gas guns best suited for MMOD investigations. Test coupons can be installed in the AVGR or HFF and subjected to particle impacts from glass or metal particles from micron to _ inch (6.35-mm) diameters and at velocities from 5 to 8 kilometers per second. The facility can record high-speed data on film and provide damage assessment for analysis by the Principle Investigator or Ames personnel. Damaged articles can be installed in the Arc Jet facility for further testing to quantify the effects of damage on the heat shield s performance upon entry into atmospheric environments.

Fretter, Ernest F.↗
NASA NTRS2014

Gene Expression Profiling of Lung Tissue of Rats Exposed to Lunar Dust Particles

The purpose of the study is to analyze the dynamics of global gene expression changes in the lung tissue of rats exposed to lunar dust particles. Multiple pathways and transcription factors were identified using the Ingenuity Pathway Analysis tool, showing the potential networks of these signaling regulations involved in lunar dust‐induced prolonged proflammatory response and toxicity. The data presented in this study, for the first time, explores the molecular mechanisms of lunar dust induced toxicity. This work contributes not only to the risk assessment for future space exploration, but also to the understanding of the dust‐induced toxicity to humans on earth.

Zhang, Ye↗
NASA NTRS2017

Aerosol Sampling Experiment on the International Space Station

The International Space Station (ISS) is a unique indoor environment which serves as both home and workplace to the astronaut crew. There is currently no particulate monitoring, although particulate matter requirements exist. An experiment to collect particles in the ISS cabin was conducted recently. Two different aerosol samplers were used for redundancy and to collect particles in two size ranges spanning from 10 nm to hundreds of micrometers. The Active Sampler is a battery operated thermophoretic sampler with an internal pump which draws in air and collects particles directly on a transmission electron microscope grid. This commercial-off-the-shelf device was modified for operation in low gravity. The Passive Sampler has five sampling surfaces which were exposed to air for different durations in order to collect at least one sample with an optimal quantity of particles for microscopy. These samples were returned to Earth for analysis with a variety of techniques to obtain long-term average concentrations and identify particle emission sources. Results are compared with the inventory of ISS aerosols which was created based on sparse data and the literature. The goal of the experiment is to obtain data on indoor aerosols on ISS for future particulate monitor design and development.

Aerosol↗
NASA NTRS1990

Pitch angle distributions of energetic ions in the lobes of the distant geomagnetic tail

A model is presented which accounts for observed pitch angle distributions of energetic ions in the lobes of the deep geomagnetic tail. Energetic (greater than 35 keV) ion data from the ISEE-3 spacecraft obtained during 1982-1983, when the spacecraft made a series of transversals of the distant geomagnetic tail (X sub GSE greater than -238 R sub E) is considered. Analysis indicates that under usual conditions the lobe pitch angle distribution is highly peaked at pitch angles closely perpendicular to the magnetic field direction while also showing a small downtail anisotropy. It is noted, however, that during periods of solar particle enhancements the lobe distributions become much more clearly isotropic. The proposed model successfully reproduces these features of the data and also accounts for the more isotropic ion population observed in the lobe during solar particle events, when the terrestrial component of the magnetosheath source may be considered negligeable in comparison to the enhanced solar component.

Owen, C. J.↗
NASA NTRS2004

Differential Velocity between Solar Wind Protons and Alpha Particles in Pressure Balance Structures

Pressure balance structures (PBSs) are a common high-plasma beta feature in high-latitude, high-speed solar wind. They have been proposed as remnants of coronal plumes. If true, they should reflect the observation that plumes are rooted in unipolar magnetic flux concentrations in the photosphere and are heated as oppositely directed flux is advected into and reconnects with the flux concentration. A minimum variance analysis (MVA) of magnetic discontinuities in PBSs showed there is a larger proportion of tangential discontinuities than in the surrounding high-speed wind, supporting the hypothesis that plasmoids or extended current sheets are formed during reconnection at the base of plumes. To further evaluate the character of magnetic field discontinuities in PBSs, differential streaming between alpha particles and protons is analyzed here for the same sample of PBSs used in the MVA. Alpha particles in high-speed wind generally have a higher radial flow speed than protons. However, if the magnetic field is folded back on itself, as in a large-amplitude Alfven wave, alpha particles will locally have a radial flow speed less than protons. This characteristic is used here to distinguish between folded back magnetic fields (which would contain rotational discontinuities) and tangential discontinuities using Ulysses high-latitude, high-speed solar wind data. The analysis indicates that almost all reversals in the radial magnetic field in PBSs are folded back field lines. This is found to also be true outside PBSs, supporting existing results for typical high-speed, high-latitude wind. There remains a small number of cases that appear not to be folds in the magnetic field and which may be flux tubes with both ends rooted in the Sun. The distinct difference in MVA results inside and outside PBSs remains unexplained.

Yamauchi, Yohei↗
NASA NTRS1973

Noctilucent cloud sampling by a multi-experiment payload.

Two multi-experiment payloads were launched into noctilucent cloud displays above Kiruna, Sweden, on the nights of July 31 and Aug. 1, 1971. The payloads were part of the continuing Pandora II cosmic dust collection series and included: (1) Pandora 2 dust collection with in-flight shadowing photoelectric polarimeters to measure scattered light at 4100 and 5400 A, a plasma detector and an ion probe, and piezoelectric microphones. These payloads attempted to investigate noctilucent clouds by four simultaneous and independent techniques. The photometric data indicate that the first payload passed through a cloud, while the second payload did not. These results are confirmed by the particle collection experiment which indicates a higher collection on the first payload. Analysis of the chemical composition of the collected particles indicates an unusual amount of high atomic number elements.

Hallgren, D. S.↗
NASA NTRS1987

A program to study antiprotons in the cosmic rays: Arizona collaboration

The Low Energy AntiProton (LEAP) experiment was designed to measure the primary antiproton flux in the 200 MeV to 1 GeV kinetic energy range. A superconducting magnetic spectrometer, a time-of-flight (TOF) detector, and a Cherenkov counter are the main components of LEAP. An additional scintillation detector was designed and constructed to detect the passage of particles through the bottom of the Cherenkov counter. The LEAP package was launched on August 22, 1987, and enjoyed a 27 hour flight, with 23 hours of data at high altitude. Preliminary plans for data analysis include using the Micro-Vax at the University of Arizona for data reduction of the Cherenkov and S2 signals.

Bowen, Theodore↗
NASA NTRS1989

Abundances from solar flare line spectroscopy

Updating and improvement of computer codes used in the abundance analyses of solar-flare gamma-ray data are described. These modifications are itemized in detail. The abundance analysis technique was then applied to data obtained by the Gamma-Ray Spectrometer of the Solar Maximum Mission spacecraft for the 27 April 1981 solar flare to set constraints on the interacting-particle angular distribution. The results are presented. Research in several other areas was also performed and they are discussed.

Murphy, Ronald J.↗